Plant Design and Economics

https://www.objectivebooks.com/2017/06/chemical-
reaction-engineering-objective.html
Lecture 1
 Syllabus
Unit 1: Introduction Unit 3: Optimum Design Strategy for
Process Equipment and Plant Layout
Introduction to Plant Design Standard and special equipment
 Process flow sheets development Material of construction for equipment
Types of flow sheets Specification sheet
Tools of the process design Choice of equipment such as reactor
Selection of process Mass transfer equipment
Factors affecting process selection Heat transfer equipment
Types of project design Factors affecting plant location
Pilot plant Principle of plant layout
Safety factors Use of scale models
Unit 2: Process Auxiliaries and Utilities
Process Auxiliaries:
Piping design, layout, support for piping
insulation, types of valves, process control
& instrumentation control system design
Process Utilities:
Process water, boiler feed water, water
treatment & disposal, steam, compressed air
and vacuum system
Unit 4: Cost Estimation & Depreciation
Cost Estimation:
Factors involved in project cost estimation,
Total fixed & working capital, Types &
methods of estimation of total capital
investment, Estimation of total product cost,
Cost index factors involved
Depreciation:
Types & methods of determination of
depreciation, Evaluation of depreciation

Unit 5: Profitability and Project Planning

Profitability
Alternative investment & replacement
methods for profitability evaluation, Break-
Even Point, Economic consideration in
process and equipment design, Rate of
return, Payback period, Inventory control
Project Planning & Scheduling:
Introduction, PERT & CPM, Bar chart
 Unit 1
Introduction to Plant Design Journey of a finished product

Inception of Idea or a need

Process Creation/Process synthesis

Identification of best process Literature Review

Select processing mode

Raw Material and product specifications
Batch or Continuous
Process Flow Diagram

Piping and Instrumentation Diagram

Equipment Design and Specification

Economics Evaluation

Plant layout
Utility requirement

Plant location
Unit 1 Introduction to Plant Design

Role of a chemical Engineer :

As a chemical engineer you will have to :
Design, Develop , Construct , Operate (D2CO)
a chemical engineering process in which a
material undergo a change in a best possible
manner, in safe manner.

For that you have to choose a equipments their

best connection, best operation of the process
and overall the operation of the process has to
be economically viable ,safe ,reliable , and
profitable.
Unit 1 Introduction to Plant Design

How to separate ethanol water mixture ?

Which type of reactor to be used for catalytic cracking?
Which type of column to be used for CO2 or NH3 adsorption in
water?

Now development or expansion or revision of existing plant require the knowledge of

engineering principle and theories, combined with a practical understanding of the limits
imposed by environment , safety, and health concern.

One important purpose of chemical engineering is to create new material wealth that are
useful to mankind and society by chemical and biochemical transformation and or
separation of materials.
Unit 1 Introduction to Plant Design

A chemical engineer in other words works on creation of manufacturing process to

fulfill a particular need or to give solution to existing problem. The need may be
public need or commercial opportunity.

Problem of CO2 capture , Search of renewable energy, increase the conversion in

particular reaction.

All you have to do is CREATE a new facility

Inception of the basic idea for creation of new thing may be raised
 From sales department: it may be need of customer.
 To meet the competing market .
 After the evaluation of the process at laboratories scale .
 From process department to modify existing process to create new process that
may be more profitable .

So journey of development of new product starts at conceptual level and ends in the
form of fabrication and construction of plant.
Introduction to Plant Design

Plant Design: Plant design includes all

engineering aspects involved in the In some literature the meaning of
development of a new manufacturing or term Plant Design is limited to
modification of existing process either something directly related to a
expansion or revision in a Chemical and plant such as plant location ,
biochemical plant. plant layout, plant auxiliaries
It involves : services.
Economics Evaluation
Design of Industrial pieces of equipment
Developing a plant layout
Plant location
General services facilities
Process Design

Process Design: Process design establishes

Selection of Process
The sequence of chemical and physical operations
Operating conditions
Calculation of duties
Major specification
Materials of construction of all process equipment
General arrangement of equipment needed to ensure proper functioning of the plant
Iine sizes
principal instrumentation.
Process design is intended to include:

1. Flow sheet development.

2. Process material and heat balances.
3. Auxiliary services material and heat balances (utilities requirements).
4. Chemical engineering performance design for specific items of equipments
required for a flow sheet.
5. Instrumentation as related to process performance.
6. Preparation of specifications (specification sheets) in proper form for use by the
project team as well as for the purchasing function.
7. Evaluation of bids and recommendation of qualified vendor.
Thank you
 Lecture 2
General Design Consideration Date : 12/07/2021

Summary of last class

Plant Design
Process Design
Different activities performed in Process design
Discussed few examples to explain the elements of process design
Few more examples of how need /problem based solution evolved

Production of Phthalic anhydride :

• Oxidation of Naphthalene in concentrated H2SO4 in presence of Mercury sulphate
• Catalytic vapor phase oxidation of Naphthalene in air in presence of Vanadium oxide
catalyst
• Today naphthalene feed stock has been superseded by the use of O-xylene
• In O-xylene process , O-xylene oxidation occurs in presence of V2O5 +TiO2 and
alternatively MoO3 and CaO. MnO are used

C6H4(CH3)2 + 3 O2 → C6H4(CO)2O + 3 H2O 70% selectivity

10% of Maleic anhydride is also produced

C6H4(CH3)2 + 7+1/2 O2 → C4H2O3 + 4 H2O + 4 CO2

Production of Sodium Carbonate:
Leblanc process (1880)
2NaCl + H2SO4 → Na2SO4 + 2HCl,
Na2SO4 + 2C → Na2S + 2CO2
Na2S + CaCO3 → Na2CO3 + CaS (black ash) HCl and CaS are two waste generated
Solvay process (1900)
NaCl + NH3 + CO2 + H2O → NaHCO3 + NH4Cl
2NaHCO3 → Na2CO3 + H2O + CO2
2NH4Cl + CaO → 2NH3 + CaCl2 + H2O CaCl2 is the only waste products

By 1900, 90% of sodium carbonate was produced by the Solvay process, and the last
Leblanc process plant closed in the early 1920s
NaOH Production :
Saturated NaCl is electrolysed : Graphite anode, steel cathode
 Diaphragm electrolytic cell (10-12% NaOH)
 Mercury electrolytic cell (50-70% NaOH)
Water soften process
Temporary hardness of water may be removed by adding Ca(OH)2
Temporary and permanent hardness of water may be removed
• by adding Na2CO3
• By distillation
• By Zeolite softening
• Sodium hexametaphosphate
• Reverse Osmosis
Calgon can be used to remove permanent hardness
General Design Consideration

The development of complete plant design involves consideration of many different topics:

Health
Safety
Loss prevention
Environmental consideration
Plant location
Plant Layout
Plant Operation
Plant Control
Utilities
Structural Design
Material handling
Material storage

The overall economics picture generally dictate s whether the proposal facility
will receive management approval
Health and Safety Hazardous

Potential health hazardous from a material used in chemical process is a function of

inherent toxicity and time of exposure (Short term and long term exposure )

1. Safety Hazard:
Material having immediate injury after exposure comes in the category of Safety
Hazard
Examples : Styrene leakage in May 2020 at LG polymers plant in Vishakhapatnam,
Bhopal gas tragedy ,MIC leakage

2. Industrial health and hygiene hazard :

Material having whose effect is apparent after long term exposure
Measurement of toxicity :

1. LD50
For the short term effect toxicity is expressed as LD50
2. Threshold Limit Value (TLV)
For long term effect : Permissible exposure limit PEL of concentration for the long
term effect is set by threshold limit value (TLV)
Publication of TLV:
TLV limit published by : Occupational Safety and Health administration (OSHA
In India : Directorate General Factory Advise Service and Labor Institute (DGFALI)
Control of Health hazard : They must be recognized and evaluated : Material Supply
Data Sheet (MSDS)
 Safety

Every attempt should be made to incorporate facilities for health and safety protection
of plant personnel in the original design these includes :
protected walkways , platforms , stairs , work areas.

Safety Regulation

Safety Regulation in India published by Ministry of Labor and employment to provide

A safe and healthful working conditions and to prepare hman resource
1. The Factories Act, 1948
2. The Factories Act, 1948
3. The Mines Act, 1952
4. The Dock Workers (Safety, Health & Welfare) Act, 1986
5. The Dock Workers (Safety, Health & Welfare) Act, 1986

These acts are amended time to time……………….

 Loss prevention

Loss : Financial loss associated with an accident

cost of repairing replacement of damaged facility
Loss of earning from lost production
Prevention :The process designer must be aware of these loses that may occur due
to various hazards and risk involves with hazards and should try to reduce the
hazard to an acceptable limit
Loss prevention :
1. Identification and assessment of the major hazards
2. Control of the hazards by most appropriate means : containment , substitution ,
improved maintenance etc.
3. Control of the process : prevention of hazard conditions in process operation by
using automatic control system , relief value , interlocks , alarm etc.
4. Limitation of loss when an incident occurs
Identification and assessment of the major hazards
 Hazards and operability study (HAZOP study )
 Fault Tree analysis FTA
 Failure mode and effect analysis FMEA
 Safety index
 Safety audit
Environmental Protection

Environmental Protection
• Environmental Impact Statement
• Environmental Impact Assessment
• Prevention of Air, Water, Soil and Solid Waste
Various governmental agencies issue regulations to prevent environmental pollution
a designer must be aware of all these
Environmental regulations and Acts by Indian Government
Today’s Absent no. 3,4,5,8,9,14,15,16,20,23,31,38,
44 60,62,65,67,71,93,96
Lecture 3
Selection of air pollution equipment

1. Particulate matter s :
Separated by mechanical forces :
Equipments used are :
•Cyclone separator
• Mechanical collector such as Impingement and Dynamic separator
•Electrostatic separator.

2. Gaseous pollutants : separated by chemical and physical forces

Methods used are:

Absorption : Gas liquid absorption in packed, plate or spray tower

Adsorption : Adsorption of gas on dry adsorbent such act activated carbon, molecular
sieves .
Condensation: It is carried out only when solvent concentration is very high and solvent is
worth recovery.
Incineration : If gas stream has no recovery value incineration is used
 Direct flame
 Catalytic oxidation
 Selection of equipment for the removal of particulates from air

Particles diameter and stream velocity determines the separation efficiency of a

equipment , Therefore, appropriate equipment should be selected

Selection of appropriate control device requires consideration of pollutants being handled

and feature of the control device.
Cost
Water treatment techniques

There are two way we can deal with waste water

1. Recovery of the waste

2. Treatment of waste

• One of the function of designer is to decide which treatment process or combination

of processes will best perform the necessary task of cleaning up the waste water
effluent evolved.

This treatment can be

1. Physical
2. Chemical
3. Biological

Solid waste management

Recycling and chemical conversion , Incineration, Pyrolysis , landfill

 Plant Location

Geographic location of a final plant can have a strong influence on the success of
An individual industry.
Various actor involve in selection of Plant location are
Raw materials availability
Market
Energy availability
Climate
Transportation facility
Water supply
Waste Disposal
Labor Supply
Taxation and legal restriction
Site characteristics
Flood and fire protection
Community factor
 Plant Layout

•It is the arrangement of processing area, storage area and handling area in a most
efficient way.
•It is the arrangement of processing units and layout of equipments in a single
processing unit

•Plant layout play an important role in determining in construction and manufacturing

cost and thus must be planned carefully.

•At what design stage do we prepare a plant layout?

•It is done after completion of process flow diagram and before detailed piping,
structural and electrical design begin

•There are various factor we need to consider before preparing a plant layout
 Structural Design

One of the important aspects of Structural Design is foundation design for process
equipment and vibrating machines,

Purpose of foundation is ???

Types of foundation depends upon the types of load and soil characteristics
It is therefore important to know the soil Characteristics at plant site before
structural design can be begin

Must calculate bearing pressure of land :

the Allowable bearing pressure for rock 30*10E5 kg/m2, Soft clay it is 10E4kg/m2

•Maintenance difficulties encountered with floor roof should be given particular attention
in a structural design.

•Corrosive effects of the process , cost of construction, and climatic conditions must be
considered when choosing structural design.
Material Storage

Adequate storage facilities for raw materials , intermediate products , final products
recycle materials , off grade materials , and fuel are essential to the operation of process
Plant.

liquids is generally handled by closed spherical or cylindrical tanks to prevent the escape
of volatiles and minimize contamination.

Floating roof tanks : with vapor pressures which are below atmospheric pressure at
the storage temperature
Vapor-tight tank: Liquids with vapor pressures above atmospheric must be stored in vapor-
tight tanks capable of withstanding internal pressure.

Gases are stored at atmospheric pressure in wet- or dry-seal gas holders.

•Pumping the gas into underground strata is the cheapest method available.
•High-pressure gas is stored in spherical or horizontal cylindrical pressure
vessels

Solid materials are stored in weather-tight tanks with sloping floors or in outdoor bins and
mounds.
Solid products are often packed directly in bags, sacks, or drums.
 Lecture 4
MATERIALS HANDLING 16/7/2021
MATERIALS HANDLING within the plant

Materials-handling equipment

Class of liquids, solids, and gases

Continuous Batch
Liquids and gases : pumps and blowers; in pipes, flumes, and ducts; and in containers such
as drums, cylinders, and tank cars.
Solids : conveyors, bucket elevators, chutes, lift trucks, and pneumatic
systems.
MATERIALS HANDLING outside plant

Pipeline design : The design and specification of the pipeline

Local and federal regulations must be strictly followed in the design and specification of the
pipeline.
Transportation by rail, ship, truck, or air transportation,

Receiving or shipping facilities should be provided in the design

 MATERIALS HANDLING

The selection of materials-handling equipment : depends upon the cost and the work
to be done.

Factors that‘ must be considered in selecting such equipment include:

1. Chemical and physical nature of material being handled

2. Type and distance of movement of material
3. Quantity of material moved per unit time
4. Nature of feed and discharge from materials-handling equipment
5. Continuous or intermittent nature of materials handling

The existence of special hazards, including corrosion, fire, heat damage, explosion,
pollution, and toxicity will frequently influence the design.

The most difficult hazards is corrosion. This is generally overcome by the use of a
high-first-cost, corrosion resistant material
 UTILITIES
1. Power
2. Steam
3. Water
Power
Fuel-burning plants and hydroelectric installations
Agitators, pumps, hoists, blowers, compressors, and similar equipment are usually
operated by electric motors

When a design engineer is setting up the specifications for a new plant, a decision must
be made on whether to use purchased power or have the plant set up its own power
unit.
The engineer should recognize the different methods for transmitting power and
must choose the ones best suited to the particular process under development
Steam
Steam is generated from whatever fuel is the cheapest, usually at pressures
of 450 psig (3100 kPa) or more
 Water

Water for industrial purposes can be obtained from one of two general sources: the
plant’s own source or a municipal supply.

Before a company agrees to go ahead with any new project, it must ensure itself of
a sufficient supply of water for all industrial purposes

PATENT CONSIDERATIONS

An engineer, therefore, should have a working knowledge of the basic practices and
principles of patent law.?
A new design should be examined to make certain no patent infringements are involved.
Maintenance

Sufficient space for maintenance work on equipment and facilities must be provided in
the plant layout, and the engineer needs to consider maintenance and its safety
requirements when making decisions on equipment.

A close-coupled motor pump utilizing a high speed motor may require less space and
lower initial cost than a standard motor combined with a coupled pump. However, if
replacement of the impeller and shaft becomes necessary, the repair cost with a close-
coupled motor pump is much greater than with a regular coupled pump.

A compact system of piping, valves, and equipment may have a lower initial cost and be
more convenient for the operators’ use, but maintenance of the system may require
costly and time-consuming.
 PROCESS DESIGN DEVELOPMENT

A principle responsibility of the chemical engineer is the design, construction,

and operation of chemical plants.
A. Development of design database
The engineer must continuously search for additional information: kinetic data,
Thermodynamic data, thermo physical properties

1. Literature survey : several literature indexes are extremely helpful in searching the
current literature Recent publications
Chemical abstract
Engineering index
Applied science and Technology Index
Perry’s Chemical Engineering Handbook
Unit Operation handbook
Hand book of reactive chemical hazards
Standard handbook of hazardous waste treatment and disposal
Kirk-Othmer Encyclopedia of Chemical technology
Toxic chemical release inventory
Chemical market reporter
2. Operation of existing process plants, and laboratory and pilot-plant data
 B. Process Creation
This part of design involves synthesis of various configuration of processing operation
that will produce a product in a reliable safe and economical manner with high yield
and minimum by-product

This involves use of heuristics or rule of thumb ,

Decision tree analysis and mathematical programming

C. Process mode

Process mode : decide a processing mode batch or continuous mode before flow sheet
development
Continuous mode : Petroleum , plastics , solvents , commodity chemicals
Batch mode : Specialty chemical , Pharma products , electronics materials

55,60,62,64,66,71,72,76,93,101,103, absent no, 3,17,23,25,28,29,35,38,43,44 64

16 / 7 2021
D. Raw Material and Product specifications
Once the operational mode is finalized, designer should establish a number of
specifications, That can be define the state condition of raw materials and product.
Such as Flow rate , compositions, phase, form (particles size distribution),
Temperature, Pressure etc.
D. Process synthesis steps
It involves the selection of processing operations to convert the raw material to
product s. The basic processing operations are used to eliminate property difference
between inlet out let streams
Process Flow Sheet synthesis

Process Flow Sheet Processing mode Decision on raw materials

and by products

Assembling different configurations of these

Principle operations
process operations
How do you select mangoes, if you want to prepare mango shake ? Any Criteria ??
It is easy to select mango…
But selection of best process out of many or in other words elimination of the process
alternatives is not as simple as selection mango..we need some criteria.
 Raw Material 1 Configuration 1

Raw Material 2 Configuration 2

Raw Material 3 Configuration 3 Product and

by -product
Raw Material 4 Configuration 4

Raw Material 5 Configuration 5

Each configuration has certain unit operations and unit process

But designing such a large no of process alternatives is very time consuming.

When design alternatives are suggested, they must be tested for fitness of purpose.
In other words, the design engineer must determine how well each design concept
(solutions) meets the identified need.
In the past this creative activity was normally performed from experience gained in similar
processing situations and use of heuristics or rule of thumb.

Each configuration may be examined based on some yard stick

What is that Yard stick : Least capital and operating cost + high yield + Environmentally
friendly +least hazardous + ease of start up …..etc.

Design engineer approaches in a very artistic way, in a very much similar to a painter :
suppress all other information except the most essential
Look only the cost of expensive equipment
Economic trade off to reduce the overall capital and operating cost

Not all alternatives can satisfy all criteria therefore we have to shortlist few best process,
There may be few methods work good on economics criteria :
For e.g. Method 1 , Method 2, Method3 are economically viable

These methods must be compared in order to select the one that is best situated. This
comparison certainly can be accomplished through the development of complete design
for each process.
However in many cases one or two potential solution can be eliminated by comparison of
essential variable items and detail design for each process will not require.
Following should be considered in a comparison of such types :

1. Technical Factors 2. Raw Material

a. Process flexibility a. Present and future availability
b. Continuous semi continuous batch operation b. Processing required
c. special control involved c. Storage requirements
d. Commercial yield
3. Waste products and by-
e. Technical difficulties involved
products
f. Energy requirements
a. Amount produced
g. Special auxiliaries required
b. Value of waste
h. Possibility of future developments
c. Potential market and use
i. Health and safety hazardous involved
d. Manner of discard
e. Environmental aspects
 6. Costs
4. Equipment a. Raw material
a. Availability b. Energy
b. Material of contraction c. Depreciation
c. Initial cost d. Other fixed charges
d. Maintenance and installation e. processing and overhead
costs f. Special labor requirement
e. Replacement requirements g. Real estate
f. Special designs h. Patent right
i. Environmental controls

7. Time factor
5. Plant Location a. Project completion deadline
a) Amount of land required b. Process development require
b) Transportation facilities c. Market time line
c) Proximity to market and raw material d. Value of money
sources
d) Availability of service and power 8. Process Consideration
facilities a. Technology availability
e) Availability of labor b. Raw Materials common with
f) Climate other processes
g) Legal restrictions and taxes c. Consistency of product within
company
d. General company objective
 Types of Process Design

Depending on the accuracy and detail required, design engineers generally classify design
in the following manner :

1. Order of magnitude designs

2. Study design or factored design
3. Preliminary design
4. Detailed estimate designs
5. Final process designs

First two methods are quick estimating procedure that are sometime require to calculate level
of investment required for a proposed project.
Preliminary designs
Preliminary designs are ordinarily used as a basis for determining whether further work
should be done on the proposed process. In preliminary design, designer use flow sheet
that was developed in the process creation step .
The design is based on approximate process methods.
A rough cost estimates are prepared.
Few details are included.
The time spent on calculations is kept at a minimum.
Various phases of preliminary design

Establish the bases for design : First step in preliminary design is establish the bases for
design such as : specifications of raw materials and products, expected annual operating
factor , temperature of cooling water, available steam pressure, fuel used, value of by
products, etc.
Generate a simplified flow diagram : Identify the number of processes that are involved
and unit operations required

Preliminary Material Balance : this can very quickly eliminate the some of the alternatives.

Complete Material and Energy balance : Evaluation of flow rate and stream conditions for
the remaining alternatives from complete material and energy balance . T, P , Compositions,
enthalpy , vapor –liquid composition, heat duties , of every stream are determined .

Equipments identifications and specifications : Prepare a summary of equipments and

their specifications in a tabular form ….
Utilities and labor requirement
Economics evaluation : Estimate capital investment and total product cost.
Final step : prepare a report to present the results of design work.
Detailed-estimate design

In this type of design, the cost and- profit potential of an established process is
determined by detailed analyses and calculations.

 Exact specifications are not given for the equipment.

Drafting-room work is minimized.

Firm process design

When the detailed-estimate design indicates that the proposed project should be a
commercial success, the final step before developing construction plans for the plant is
the preparation of a firm process design.

1,2,3,5,9,21,23,25,31,42, 55,66,67,68,71,86,90,103

19 7 21
Lecture 6
Detailed-estimate design
In this type of design, the cost and- profit potential of an established process is
determined by detailed analyses and calculations.

 Exact specifications are not given for the equipment.

Drafting-room work is minimized.

The following factors should be established within a narrow limits before a detailed
estimate design is developed.

1. Manufacturing process
2. Material and energy balance
3. Temperature and pressure ranges
4. Raw material and product specification
5. Yield ,reaction rate , time cycle
6. MOC
7. Utilities required
8. Plant site
When this information included in the design, the results permits accurate estimation of
required capital investment, manufacturing costs, and potential profit.

Consideration should be given to the types of building , heating , ventilation , lighting ,

power , drainage , waste disposal , safety facilities, Instrumentation
Firm process design

When the detailed-estimate design indicates that the proposed project should be a
commercial success, the final step before developing construction plans for the plant is
the preparation of a firm process design.

The final process design is prepared for construction and purchasing from detailed
estimate design.
Detail drawing for fabrication of the equipment
Equipment specification
Material specification
Complete plant layout
Printouts and instructions for construction are developed
Piping diagram
Detail Specifications for
Warehouses , Laboratories, Guardhouses , Fencing, Change house , Transportation
are prepared
 SCALE-UP IN DESIGN

Pilot-plant tests

When accurate data are not available in the literature.

When past experience does not give an adequate design basis.

Pilot-plant tests is necessary in order to design effective plant equipment.

The results of these tests must be scaled up to the plant capacity.

A chemical engineer, therefore should be acquainted with the limitations of scale-up

methods and should know how to select the essential design variables.
 Pilot-plant data are almost always required for the design of filters unless specific
information is already available for the type of materials and conditions involved.

Heat exchangers, distillation columns pumps, and many other types of conventional
equipment can usually be designed adequately without using pilot-plant data.

Safety Factors
Safety Factors represents the amount of overdesign that would be used to account for not
only the change in the operating performance with time , but also the uncertainties in the
design process .

The indiscriminate application of safety factor can be very detrimental to a design.

Each equipment should be design to carry out its necessary function, then if uncertainties
are involved a releasable safety factor can be applied.
Criteria for safety factor :
In general design work, the magnitudes of safety factors are dictated by
 Economic or market considerations
The accuracy of the design data and calculations
Potential changes in the operating performance
Background information available on the overall process
and the amount of conservatism used in developing the individual components of the
design.

Each safety factor must be chosen on basis of the existing conditions, and the chemical
engineer should not hesitate to use a safety factor of zero if the situation warrants it.
20/7/2021
absent no. 3,,6,15,16,23,,8,47, 60,66,68,70,96,104
 Construction and Operation

When a definite decision to proceed with the construction of a plant is made, there is
usually an immediate demand for a quick plant startup.

 Timing is important in plant construction.

 Long delays may be encountered in the fabrication of major pieces of equipment, and
deliveries often lag far behind the date of ordering.

These factors must be taken into consideration when developing the final plans

Project Evaluation and Review Technique (PERT) or the Critical Path Method
(CPM) are used to evaluate and track the progress of the plant.

 The chemical engineer should always work closely with construction personnel during
the final stages of construction and purchasing designs.

Factors which might delay construction are given first consideration

Construction of the plant may be started long before the final design is 100 percent
complete.
Correct design sequence is then essential in order to avoid construction delays.

During construction of the plant, the chemical engineer should visit the plant site
to assist in interpretation of the plans and learn methods for improving future
designs.

The engineer should also be available during the initial startup of the plant and
the early phases of operation.

By close teamwork between design, construction, and operations personnel, the
final plant can develop from the drawing-board stage to an operating unit that can
function both efficiently and effectively.
 FLOW DIAGRAMS

The chemical engineer uses flow diagrams to show the sequence of equipment
and unit operations in the overall process, to simplify visualization of the
manufacturing procedures, and to indicate the quantities of materials and energy
transfer.

These diagrams may be divided into three general types:

(1) Qualitative
(2) Quantitative
(3) Combined-detail.

A qualitative flow diagram indicates the flow of materials, unit operations involved,
equipment necessary, and special information on operating temperatures and pressures.

A quantitative flow diagram shows the quantities of materials required for the process
operation.
Preliminary flow diagrams are made during the early stages of a design project.

As the design proceeds toward completion, detailed information on flow quantities and
equipment specifications becomes available, and combined- detail flow diagrams can be
prepared.

This type of diagram shows the qualitative flow pattern and serves as a base reference
for giving equipment specifications, quantitative data, and sample calculations.

A combined-detail flow diagram shows the location of temperature and pressure

regulators and indicators, as well as the location of critical control valves and special
instruments.

Each piece of equipment is shown and is designated by a defined code number.

For each piece of equipment, accompanying tables give essential information, such as
specifications for purchasing, specifications for construction, type of fabrication,
quantities and types of chemicals involved, and sample calculations.
23 7 2021
8,16,35,38,44,49, 60,66,70,74,79,101,103
 Flow Sheet Synthesis and development 26/ 07/2021

Flow Sheet: a schematic representation of a chemical process

Steps in preparation of flow sheet :

Process synthesis, development, evaluation and selection of the most appropriate

processing arrangement of a chemical process.

Selection of the flow sheet is one of the most important steps in the design of a
chemical plant , because only from the most optimal flow sheet can the most profitable
safe and environmentally sound final design be obtained
Development of Flow Sheet

Design procedure

1. Hierarchical method: based on heuristic approach or past experience , common

sense, identify all alternatives and let alone analyzing them.
2. Algorithmic method : based on mathematical programming procedure that include
optimization techniques

Hierarchical method has been used with resalable success for the development of
flow sheet of more routine process BUT with considerably smaller success in more
complex process .

Algorithmic method has had similar experiences in flow sheet, however recent
computerization made it more easier to design a more complex chemical processes.
Hierarchical method

A generalized steps in a hierarchical scheme for flowsheet synthesis and development :

Process Information >Input out diagram >Function Diagram >Operation diagram>

Flow-sheet

Process Information:

Technical and patent literature fro information about the product

 Study market conditions
 Pricing of the product
 Key properties data
 Pilot plant data if the process is new
Input out diagram

It shows all material input and out put streams with a stoichiometric balance
Before input output you must do :
Examine all reaction path > economics analysis > eliminate those for which raw
material cost exceeds that of the product or and those which are infeasible.
Function Diagram

For each particular chemical reaction path , indicate all major functions of the
process and material flow to and from these functions , this step involves the
identification of the major functions or sub processes that must be achieved by the
process
Reaction box : each reaction
Preprocessing box : for material preprocessing
Separation box :
Finishing box : for converting each product in final from
Operation diagram

In this step technology to be used to accomplish each of the operations is

selected.
Preprocessing technology is chosen
Types of reactor
Ranges of T, P, X, S estimated
Purification and separation techniques are determined : phase separation ,
stripping , distillation , membrane separation , extraction , or other technology to
be used
26 7 21
Absent no. 3,8,14,21,23,30,31,33,34,44,45,50 66,67,70,74,79,104
Flow-sheet

The final steps in defining a flow-sheet are to estimate key equipment performance
parameters , improve the mass balances , estimate approximate energy balance , define
the separation trains, and develop heat integration opportunities.

Performance parameter for reactor: conversion and yield form the design basis
Select the conversion at this stage of flow sheet evaluation ….

Mass and energy balance : mass balance initiated by selecting conversion basis and
HE, Separation train (series of separation unit ) are evaluated afterwards.

Energy balance follows mass balance using thermodynamic properties from the literature

Separation operation must be sufficiently defined that their energy requirement can be
estimated if they are to be included in the heat integration.
Eg operating pressure and reflux ratio of distillation column must be specified
Separation trains
Most separation processes results in two product streams
Therefore to separate a mixture containing c components in to c pure products , require
C-1 no of distinct separation operations . Thus separating a multi component mixture into
its various pure components require a train of separation train.

This separation may require a different Separation technology after their selection a
sequence is to be established.

General rule of thumb for sequencing

1. When possible , reduce the separation load by stream splitting and blending
2. Difficult separations are best saved for last
3. Remove high concentration components early In the sequence
4. Remove components not normally present in the process soon after use
5. Avoid wide excursions in temperature and pressure , particularly since cooling at above
ambient is relatively inexpensive and heating is more expensive while cooling at
temperature below ambient is very expensive.
Some more heuristics specific for distillation
1. Remove thermally unstable corrosive or reactive components early in the sequence
2. Remove the final products one by one , starting with most volatile and contining in
order of decreasing volatility
3. Remove the components present in the largest amounts early
4. Sequence in order of decreasing relative volatility , that is do more difficult separations
later
5. Sequence in order of increasing product purity requirements
6. Sequence so that distillate and bottom product flow rates are as equal as possible

Heat Exchange

Since there are process equipment and streams that require heating as well as cooling ,
Opportunities nearly always exist for exchanging heat and reducing utilities required.
Therefore, initial heat integration opportunity must be searched
The Flow-sheet Importance

Shows the arrangement of the equipment selected to carry out the process.
 Shows the streams concentrations, flow rates & compositions.
 Shows the operating conditions.
 During plant start up and subsequent operation, the flow sheet from a basis for
comparison of operating performance with design. It's also used by operating
personnel for the preparation of operating manual and operator training.

Flowsheet Presentation

1- Block diagram
1. Represent the process in a simplified form.
2. No details involved.
3. Don’t describe how a given step will be achieved.
 When is it used?
1. In survey studies.
2. Process proposal for packaged steps.
3. Talk out a processing idea.

2- Pictorial Flow Sheet

The equipments are normally drawn in a stylized pictorial form. For tender
documents or company brochures actual scale drawing of the equipment are
sometimes used.
 Types of pictorial flow-sheets

a) Process Flow Diagram (PFD)

A PFD is a simplified flow diagram of a single process unit, a utility unit, a complete
process module.

The purpose of a PFD is to provide a preliminary understanding of the process system

indicating only the main items of equipment, the main pipelines and the essential
instruments, switches and control valves.

A PFD also indicates operating variables, such as mass flow, temperatures and
pressures, which are tabulated at various points in the system.

The PFD is a document containing information on:

1. Process conditions and physical data of the main process streams.

2. Main process equipment with design data.
3. Main Process lines.
4. Mass (material) balance.
If the PFD doesn’t contain any data about the flow rates, it is called a qualitative flowsheet, while if
the flow rates are involved the PFD is called a combined flowsheet in which qualitative information
and quantitative data are combined on the basis of one flowsheet.
b) Piping and Instrumentation Diagram (P & ID) (mechanical flow diagram)

A P&ID diagram shows the arrangement of the process equipment, piping, pumps,
instruments, valves and other fittings. It should include:

1. All process equipment identified by an equipment number.

2. All pipes identified by a line size, material code and line number.
3. All valves with an identified size and number.
4. Fittings.
5. All pumps identified by a suitable code number.
6. All control loops and instruments.

c) Utility Flowsheet (Process Engineering Utility Flow Diagram (PEUFD))

Used to summarize and detail the interrelationship of utilities such as air, water
(various types), steam (various types), heat transfer mediums, process vents and
purges, safety relief blow-down, etc., to the basic process.
The amount of detail is often too great to combine on other sheets, so separate
sheets are prepared.
The PEUFD is a document containing information on:
Main distribution or arrangement of each individual utility system, expect
electrical systems.
30 7 2021
66,79,95,99
absent no. 6,17,23,31,35,45
 What is capital ?
Where it Come form?
And Where can we use capital ?

Capital is "a stock of accumulated wealth

Capital is savings that may be used as the owner decides

 One use of the savings is investment; that is, to use the savings ". . . to promote the
production of other goods, instead of immediate enjoyment…

This slide is not relevant to Students

Investment in an Industrial plant

A large sum of money required before a industrial plant can be in operation

Money is require :
To purchase and install the required machinery and equipment.
To procure land
To generate service facilities
To complete plant erection
In piping, controls, and other services
To pay the expenses involved in the plant operation before sales revenue
becomes available.
Now WAIT A WHILE AND THINK
Why to know about cost and investment ???????

IT IS BECAUSE :
An plant design is acceptable only when a plant that can produce a
product which will sell at a profit.
Since net profit equals total income minus all expenses, it is
essential that the chemical engineer be aware of the various types of costs associated
with each manufacturing step.
Capital Investment in an Industrial plant

Total capital investment (TCI)

Fixed-capital investment (FCI) Working capital investment (WC)

Manufacturing fixed- 1. Start-up cost.

Nonmanufacturing fixed- capital 2. Initial catalyst
capital investment
investment (indirect cost) charges.
(direct cost)
3. Raw materials and
Land
construction overhead

intermediates in the
Expenses for: Construction of processing,
process.
Process equipments administrative buildings and other
4. Finished product
Site preparation offices
inventories.
Piping Warehouses
5. Funds to cover
Instruments Laboratories,
outstanding accounts
Insulation Transportation
from customers
Foundations Shipping, and receiving facilities
Auxiliary facilities Utility and waste disposal facilities,
Shops, and other permanent parts
of the plant
Fixed-Capital Investment for physical equipment and facilities in the plant

Working Capital Investment :Working capital is the additional investment needed,

over and above the fixed capital, to start the plant up and operate it to the point when
income is earned. It is kept with the owner to pay salaries, raw materials and products
on hand, and handle other special items.

Working capital can vary from as low as 5 per cent of the fixed capital for a simple, single-
product; to as high as 30 per cent for a process producing a diverse range of product
grades for a sophisticated market, such as synthetic fibres.

A typical figure for petrochemical plants is 15 per cent of the fixed capital.

Most of the working capital is recovered at the end of the project

Some definitions of profit
Gross profit before depreciation

The difference between the income from sales(si ) and operating costs(Co ) is the gross
profit before depreciation charge = si – co

Gross profit after depreciation

Gross profit after depreciation(G2) =si – coj- dj

Net Profit Income tax = ɸ (si – coj - dj)

Net Profit=G2 - income tax Income tax : 30-35% of G2

Net flow back to the reservoir ɸ : Fixed income tax rate

Aj = (si – coj - dj) (1- ɸ) + ɸ dj0

Example : if revenue from sales =100 and Operation cost is 20 and

Depreciation is 10 then

Gross profit= 100-20= 80

Gross profit after depreciation 80-10=70, income tax =70 *0.3=21
net profit after tax => 70-21=49
Cash Flow diagram
1. Sources of Equipment

2. Price Fluctuations

3. Company Policies
Safety regulations
Accounting procedures
Company policies with reference to labor unions

4. Operating Time and Rate of

Production
Operating Time and Rate of Production

One of the factors that has a major effect on the profits is the fraction of time a
process is in operation.

If equipment stands idle for an extended period, there may

not be investment in raw materials and labor costs but cost
maintenance, protection, and depreciation, continues. And
at the same time no revenue

Some time must be allowed periodically to perform scheduled routine maintenance;

however, downtime should be kept to a necessary minimum, as it is one of the chief
sources of poor profitability in process plants.
cont….

Sales demand, rate of production, and operating time are closely interrelated.

The ideal plant should operate under a time schedule that gives the
maximum production rate consistent with market demand, safety,
maintainability, and economic operating conditions.

In this way, the total cost per unit of production is

minimized because the variable costs averaged
over time are low.

If the production capacity of the process is greater than the sales demand,
the operation can be operated continuously at reduced capacity or
periodically at full capacity.
cont….

Figure : shows the effect on costs and profits based on the rate of production.
ESTIMATION OF CAPITAL INVESTMENT

Most estimates of capital investment are based on the cost of the equipment required.

The most significant errors in capital investment estimation are generally due to omissions
of equipment, services, or auxiliary facilities rather than to gross errors in costing.

Breakdown of fixed-capital investment items for a chemical process

 Types of Capital Cost Estimates

Predesign cost estimates

Firm estimates

Study estimate
Detailed estimate

Order-of-magnitude estimat Definitive estimate

Preliminary estimate
 Types of Capital Cost Estimates

An estimate of the capital investment for a process may vary from a pre-design
estimate based on little information except the magnitude of the proposed project
to a detailed estimate prepared from complete drawings and specifications.
A. Predesign cost estimates

Order-of-magnitude estimate {ratio estimate) based on similar previous cost data;

probable accuracy of estimate over ±30 percent.

Study estimate (factored estimate) based on knowledge of major items of equipment;

probable accuracy of estimate up to ±30 percent.

Preliminary estimate (budget authorization estimate or scope estimate) based on

sufficient data to permit the estimate to be budgeted; probable accuracy of estimate
within ±20 percent.
B. Firm estimates

Definitive estimate (project control estimate) based on almost complete data but
before completion of drawings and specifications; probable accuracy of estimate
within ±10 percent.

Detailed estimate (contractor's estimate) based on complete engineering drawings,

specifications, and site surveys; probable accuracy of estimate within ±5 percent.
COST INDEXES

Most cost data that are available for making a preliminary or predesign estimate are
only valid at the time they were developed. Because prices may have changed
considerably with time due to changes in economic conditions, some method must
be used for updating cost data applicable at a past date to costs that are
representative of conditions at a later time

A cost index is an index value for a given time showing the cost at that time relative
to a certain base time. If the cost at some time in the past is known, the equivalent
cost at present can be determined by multiplying the original cost by the ratio of the
present index value to the index value applicable when the original cost was
obtained,

Cost indexes can be used to give a general estimate, but no index can take into account
all factors, such as special technological advancements or local conditions.

The common indexes permit fairly accurate estimates if the period involved is less than
10 years.
Different Cost Index

 Marshall and Swift all-industry and process-industry equipment indexes

 Engineering News- Record construction index
 Nelson-Farrar refinery construction index
 Chemical Engineering plant cost index
 Purchased Equipment
The cost of purchased equipment is the basis of several predesign methods for estimating
capital investment.
Sources of equipment prices, methods of adjusting equipment prices for capacity, and
methods of estimating auxiliary process equipment are therefore essential to the
estimator in making reliable cost estimates.

There are three major category of process equipment (1) processing equipment, (2) raw
materials handling and storage equipment, and (3) finished-products handling and
storage equipment

Estimating Equipment Costs by Scaling

It is often necessary to estimate the cost of a piece of equipment when cost data are
not available for the particular size or capacity involved. Predictions can be made by
using the power relationship known as the six-tenths factor rule.
If the new piece of equipment is similar to one of another capacity for which cost
data are available
 According to this rule, if the cost of a given unit b at one capacity is known, the cost
of a similar unit a with X times the capacity of the first is X 6 times the cost of the
initial unit.

Cost of equipment a = (cost of equipment b )X0.6

Problem :
The purchased cost of a 0.2-m3, glass-lined, jacketed reactor (without drive) was
$10,000 in 1991. Estimate the purchased cost of a similar 1.2-m3, glass-lined, jacketed
reactor (without drive) in 1996. Use the annual average Chemical Engineering plant
cost index to update the purchase cost of the reactor.
Value of exponent for different equipment
 Purchased-Equipment Delivery

Purchased-equipment prices are usually quoted as f.o.b. (free on board, meaning that
the purchaser pays the freight). Clearly freight costs depend upon many factors, such
as the weight and size of the equipment, distance from source to plant, and method of
transport.
For predesign estimates, a delivery allowance of 10 percent of the purchased
equipment cost is recommended.

Purchased-Equipment Installation

Installation of process equipment involves costs for labor, foundations, supports,

platforms, construction expenses, and other factors directly related to the erection of
purchased equipment.
It varies from 25 to 55 percent of the delivered purchased-equipment cost

Equipment installation costs and piping costs.

Instrumentation and Controls

Instrument costs, installation labor costs, and expenses for auxiliary equipment and
materials constitute the major portion of the capital investment required for
instrumentation.

Total instrumentation and control cost depends on the amount of control required
and may amount to 8 to 50 percent of the total delivered equipment cost.
For the normal solid-fluid chemical processing plant, a value of 26 percent of the
delivered purchased-equipment cost is recommended.

Piping
The cost for piping covers labor, valves, fittings, pipe, supports, and other items involved
in the complete erection of all piping used directly in the process. This includes raw
material, intermediate-product, finished-product, steam, water, air, sewer, and other
process piping. Since process-plant piping can run as high as 80 percent of delivered
purchased-equipment cost or 20 percent of the fixed-capital investment
Electrical Systems
The electrical systems consist off our major components, namely, power wiring,
lighting, transformation and service, and instrument and control wiring. In most
chemical plants the installed cost of electrical systems is estimated to be 15 to 30
percent of the delivered purchased-equipment cost or between 4 and 8 percent of
the fixed-capital investment.
Buildings

The cost of buildings, including services, consists of expenses for labor, materials,
and supplies involved in the erection of all buildings connected with the plant. Costs
for plumbing, heating, lighting, ventilation, and similar building services are
included.
Yard Improvements
Costs for fencing, grading, roads, sidewalks, railroad sidings, landscaping, and similar
items are all considered part of yard improvements. The cost for these items in most
chemical plants approximates 10 to 20 percent of the purchased-equipment cost.

Service Facilities
Utilities for supplying steam, water, power, compressed air, and fuel are part of the
service facilities of a chemical process plant.
Waste disposal, fire protection, and miscellaneous service items, such as shop, first aid,
and cafeteria equipment and facilities, require capital investments that are included under
the general heading of service facilities cost.

The total cost ::: ranges from 30 to 80 percent of the purchased-equipment cost with 55
percent representing an average for a normal solid-fluid processing plant.
23 8 2021
3,16,43,44,47,49 60,68,70,92,95,96,101,106
Health, Safety, and Environmental Functions

Over time, the requirements for occupational health and safety and environmental
functions in plants have increased substantially.

There do not seem to be general guidelines for estimating these expenditures at

this time.

It is highly recommended that they all be considered in the design of a plant.

These functions should not be mere add-ons, but should be integrated into the
process design itself.

Pollution prevention and pollutant minimization techniques should be part of the

design strategy.
Land

The cost for land and the accompanying surveys depends on the location of the
property and may vary by a cost factor per acre as high as 30 to 50 between a rural
district and a highly industrialized area.

Engineering and Supervision

The costs for construction design and engineering, including internal or licensed software,
computer-based drawings, accounting, construction and cost engineering,
travel, communication etc. , constitute the capital investment for engineering and
supervision.
This cost is normally considered an indirect cost in fixed-capital investment and is
approximately 30 percent of the delivered-equipment cost or 8 percent of the fixed-
capital investment for the process plant.
Legal Expenses

It is occur largely in
Land purchases
 Equipment purchase 1 to 3 percent of fixed-capital investment
 Construction contracts

And in proving compliance with government, environmental, and safety requirements also
constitute major sources of legal costs.

Construction Expenses:
Temporary construction and operation
 Construction tools and rentals
Home office personnel located at the construction site
Construction payroll
8 to 10 percent of the fixed-capital investment
travel and living
Taxes and insurance
Contingencies

A contingency amount for unexpected events and changes that inevitably increase
the cost of the project.
Events, such as storms, floods, transportation accidents, strikes, price changes,
small design changes, errors in estimation, and other unforeseen expenses, will
occur even though they cannot be predicted.

5 to 15 percent of the fixed-capital investment , with 8 percent being considered a

reasonable average value
 METHODS FOR ESTIMATING CAPITAL INVESTMENT

Method A: Detailed-Item Estimate

A detailed-item estimate requires careful determination of each individual item

Equipment and material needs are determined from completed drawings and
specifications and are priced either from current cost data or preferably from firm
delivered quotations.

Estimates of installation costs are determined from accurate labor rates, efficiencies,
and employee-hour calculations.

Complete site surveys and soil data must be available to minimize errors in site
development and construction cost estimates.

Accuracy in the ±5 percent ran

Method B: Unit Cost Estimate

It also requires detailed estimates of purchased price obtained either from quotations or
index-corrected cost records and published data

•Equipment installation labor is evaluated as a fraction of the delivered-equipment

cost.

•Costs for concrete, steel, pipe, electrical systems, instrumentation, insulation, etc., are
obtained by takeoffs from the drawings and applying unit costs to the material and
labor needs.
•A unit cost is also applied to engineering employee-hours, number of drawings, and
specifications.

• A factor for construction expense, contractor's fee, and contingency is estimated

from previously completed projects and is used to complete
this type of estimate.
where Cn is the new capital investment, E the delivered purchased-equipment cost, EL
the delivered-equipment labor cost.

fx the specific material unit cost, Mx the specific material quantity in compatible units,

fy the specific material labor unit cost per employee-hour,

ML’ the labor employee-hours for the specific material,

fe the unit cost for engineering, He the engineering employee-hours,

fd the unit cost per drawing or specification, dn the number of drawings or specifications
fF the construction or field expense factor (always greater than 1).
Depending on the detail included, a unit cost estimate should give ±10 to 20 percent
accuracy.

24 8 21
Absent no. 44,47 60,76,103,104,106
 Method C: Percentage of Delivered-Equipment Cost

This method for estimating the fixed-capital and total capital investment requires
determination of the delivered equipment cost.

The other items included in the total direct plant cost are then estimated as percentages
of the delivered-equipment cost.

The additional components of the capital investment are based on average percentages
of the total direct plant cost, total direct and indirect plant costs, or total capital
investment. This is summarized in the following cost equation:

Estimating by percentage of delivered-equipment cost is commonly used for

preliminary and study estimates.
The expected accuracy is in the ±20 to 30 percent range.
Method D: Lang Factors for Approximation of Capital Investment

Used quite frequently to obtain order-of magnitude cost estimates.

The cost of a process plant may be obtained by multiplying the equipment cost by some
factor to approximate the fixed or total capital investment.

These factors vary depending upon the type of process plant being considered.

Greater accuracy of capital investment estimates can be achieved in this method by using
not one but a number of factors.

One approach is to use different factors for different types of equipment.

Another approach is to use separate factors for installation of equipment, foundations,

utilities, piping, etc.,
where E' is the purchased equipment on an f.o.b. basis

fl : the indirect cost factor that is always greater than 1 (normally taken as 1.4),
fF: the cost factor for field labor,
fp: the cost factor for piping materials,
Fm : the cost factor for miscellaneous items, including the materials cost for insulation,
instruments, foundations, structural steel, building, wiring, painting, and the cost of
freight and field supervision,

Ei: the cost of equipment already installed,

A the incremental cost of corrosion-resistant alloy materials,

e the total heat exchanger cost (less incremental cost of alloy),

fv the total cost of field-fabricated vessels (less incremental cost of alloy), p the total
pump plus driver cost (less incremental cost of alloy), and
t the total cost of tower shells (less incremental cost of alloy).
Absent no. 56,66,72,79,92,95
17,28,29,31,44,47,50
Method E: Power Factor Applied to Plant/Capacity Ratio

Order-of-magnitude estimates relates the fixed-capital investment of a new process plant

to the fixed-capital investment of similar previously constructed plants by an exponential
power ratio.
The fixed-capital investment of the new facility is equal to the fixed-capital
investment of the constructed facility C (adjusted by a cost index ratio), multiplied
by the ratio R, defined as the capacity of the new facility divided by the capacity of
the old facility, raised to a power x.
This power has been found to average between 0.6 and 0.7 for many process
facilities.

where fe is the cost index ratio at the time of cost Cn to that at the time of C.
Method G: Turnover Ratio

A rapid evaluation method suitable for order-of magnitude estimates is known as

the turnover ratio method. The turnover ratio is defined as the ratio of gross annual
sales to fixed-capital investment.

The reciprocal of the turnover ratio is sometimes called the capital ratio or the investment
ratio
For a chemical industry, as a very rough rule of thumb, the ratio can be approximated as
0.5.
 ESTIMATION OF REVENUE

A complete cost estimate

Determination of the Determination ESTIMATION OF

capital investment revenue generated TOTAL PRODUCT COST

Revenue comes from sale of the product or products produced by the plant

The total annual revenue from product sales is the sum of the unit price of each product
multiplied by its rate of sales.

A plant is designed for a specific rate of production of the major product.

In conducting an economic analysis of a process, the engineer must establish production
rates, as a fraction or percentage of the design capacity, for each year of process
operation.

It is common in preliminary economic studies to use 50 percent for the first year of
operation because, during the start-up period, production rates are very low, the length
of the start-up period is uncertain, and the time of the year for the beginning of start-up
is unknown.

After the first year, it is common to use the design annual capacity of the plant as the
production and sales rate for each subsequent year.

This downtime allowance is typically 10 to 20 percent, based on a 24 h/day, 7

days/week, 52 weeks/ year production for continuous processes.

Product prices are best established by a market study. For established products, price
information is available in sources such as the Chemical Market Reporter.
Other sources of revenue may include sale of obsolete equipment, recovery of
working capital, and sale of other capital items.

ESTIMATION OF TOTAL PRODUCT COST

The third major component of an economic analysis is the total of all costs of operating
the plant, selling the products, recovering the capital investment, and contributing to
corporate functions such as management and research and development.

These costs usually are combined under the general heading of total product cost. The
latter, in turn, is generally divided into two categories:
Manufacturing costs and General expenses.

Manufacturing costs are also referred to as operating or production costs.

Further subdivision of the manufacturing costs is somewhat dependent upon the

interpretation of variable, fixed, and overhead costs.

31 8 2021
2,3,8,15,17,18,20,28,31,34,38,43,44 59,60,64,66,101,106,
A suggested checklist of all the costs involved in chemical processing operations
Total product costs are commonly calculated on one of three bases:

Daily basis
Unit of product basis
 Annual basis

Annual cost is probably the best choice for the purpose of economic analyses

(1) Smooth out the effect of seasonal variations

(2) Include plant on-stream time or equipment operation,
(3) Permit more rapid calculation of operating costs at less than full capacity,
and
(4) provide a convenient way of considering large expenses that occur
infrequently such as annual planned maintenance shutdowns.
 Source of information for total product cost estimates

The best source of information for total product cost estimates is data from similar or
identical projects.

A quick, reliable estimates of manufacturing costs and general expenses can be

obtained from existing records.

 Adjustments for increased costs due to inflation must be made, and differences in
plant site and geographic location must be considered.
Methods for estimating total product cost in the absence of specific information

Manufacturing Costs
All expenses directly connected with the manufacturing operation or the physical
equipment of a process plant itself are included in the manufacturing costs.
These expenses, as considered here, are divided into three classifications:
1) Variable production costs
2) Fixed charges
(3) Plant overhead costs.

Variable production costs include expenses directly associated with the

manufacturing operation. These costs are incurred for the most part only when the
plant operates,

This type of cost involves expenditures for raw materials (including transportation,
unloading, etc.), direct operating labor, supervisory and clerical labor directly applied
to the manufacturing operation, utilities, plant maintenance and repairs, operating
supplies, laboratory supplies, royalties, catalysts, and solvents.
Fixed charges

Fixed charges are expenses which are practically independent of production

rate.

Expenditures for depreciation, property taxes, insurance, financing (loan

interest), and rent are usually classified as fixed charges.
These charges, except for depreciation, tend to change due to inflation.

Depreciation is established by tax regulations, it may differ from year to year, but
it is not affected by inflation.
 Plant overhead costs

Plant overhead costs are for hospital and medical services

General plant maintenance and overhead

 Safety services,
 Payroll overhead including social security and other retirement plans, medical and life
insurance, and vacation allowances,
 Packaging
Restaurant and recreation facilities
Salvage services
 Control laboratories
Property protection
Plant superintendence
Warehouse and storage facilities
Special employee benefits

These costs are similar to the basic fixed charges since they do not vary widely with
changes in production rate.
Variable production costs

Cost of Raw Materials

The ratio of the cost of raw materials to total product cost varies considerably
for different types of plants. In chemical plants, raw material costs are usually
in the range of 10 to 60 percent of the total product cost.

Absent roll 3 9 2021

2,15,35,62,66,72,84,92
Direct price quotations from prospective suppliers are desirable for the raw materials.

Published prices are used if direct price quotations are not available .

For preliminary cost analyses, market prices are often used for estimating raw material
costs.

Chemical prices are usually quoted on an f.o.b. (free-on-board) basis.

 Any transportation charges should be included in the raw material costs when
available; 10 percent of the raw material cost,( but are highly variable).

One of the most important steps of the design process is to calculate accurate
material balances for the process
Usually the basis for a process design/Raw materail is the production rate of a key
product, that is, an output.
Operating Labor charge

Operating Labor In general, operating labor may be divided into skilled and
unskilled labor.

Hourly wage rates for operating labor in different industries at various locations can
be obtained from the Bureau of Labor publication entitled Monthly Labor Review.

For chemical processes, operating labor usually amounts to about 10 to 20 percent

of the total product cost.
Operating Labor requirement

If a flow-sheet and drawings of the process are available, the operating labor may be
estimated from an analysis of the work to be performed.

Consideration must be given to such items as the type and arrangement of

equipment, multiplicity of units, amount of instrumentation and control for the
process, and company policy in establishing labor requirements.

Second way of estimating labor requirements

 Function of plant capacity: It is based on adding the various principal
processing
. steps on the flowsheet
Operating Supervision and Clerical Assistance

A certain amount of direct supervisory and clerical assistance is always required for a
manufacturing operation.

The necessary amount of this type of labor is closely related to the total amount of
operating labor, complexity of the operation, and product quality standards.

The cost for direct supervisory and clerical labor averages about 15 percent of the cost for
operating labor. For reduced capacities, supervision usually remains fixed at the 100
percent capacity rate.
Utilities
The cost for utilities, such as steam, electricity, process and cooling water, compressed air,
natural gas, fuel oil, refrigeration, and waste treatment and disposal, varies widely
depending on the amount needed, plant location, and source.

The required types of utilities are established by the flowsheet conditions; their amount
can sometimes be estimated in preliminary cost analyses from available information
about similar operations.
Maintenance and Repairs
Annual costs for equipment maintenance and repairs may range from 2 to 20 percent of
the equipment cost.
Charges for plant buildings average 3 to 4 percent of the building cost.
In the process industries, the total plant cost per year for maintenance and repairs
ranges from 2 to 10 percent of the fixed-capital investment, with 7 percent being a
reasonable value.
For operating rates less than plant capacity, the maintenance and repair cost is
generally estimated as
 85 percent of that at 100 percent capacity for a 75 percent operating rate

 75 percent of that at 100 percent capacity for a 50 percent operating rate.

Operating Supplies
Consumable items such as charts, lubricants, test chemicals, custodial supplies, and
similar supplies cannot be considered as raw materials or maintenance and repair
materials, and these are classified as operating supplies.
The annual cost for these types of supplies is about 15 percent of the total cost for
maintenance and repairs.

Laboratory Charges
The cost of laboratory tests for control of operations and for product quality control is
covered in this manufacturing cost.

This expense is generally calculated by estimating the employee-hours involved and

multiplying this by the appropriate rate. For quick estimates, this cost may be taken as
10 to 20 percent of the operating labor.
Patents and Royalties

Patents cover many products and manufacturing processes.

To use patents owned by others, it is necessary to pay for patent rights or a royalty
based on the amount of material produced.

Even when the company involved in the operation obtained the original patent, a
certain amount of the total expense involved in the development and procurement of
the patent rights should be borne by the plant as an operating expense.

A rough approximation of patent and royalty costs for patented processes is 0 to 6

percent of the total product cost, costs specific to the patent position in question are
always preferred.

Catalysts and Solvents

Costs for catalysts and solvents can be significant and should be estimated based
on the catalyst and solvent requirements and prices for the particular process.
6 9 21
Absent no. 28,31,34,37,38, 67,72,95,98,99
Fixed Charges

Costs that change little or not at all with the amount of production are designated
as fixed costs or fixed charges.

 These include costs for depreciation, local property taxes, insurance, and loan
interest.

Expenses of this type are a direct function of the capital investment and financing
arrangement.

They should be estimated from the fixed-capital investment.

Rent is usually taken as zero in preliminary estimates.

As a rough approximation, these charges amount to about 10 to 20 percent of the

total product cost.
Depreciation

The equipment, buildings, and other material objects comprising a manufacturing

plant require an initial investment that must be paid back, and this is done by
charging depreciation as a manufacturing expense.

Depreciation rates are very important in determining the amount of income tax

Tax and depreciation

The Internal Revenue Service, under Govt. of India tax law, determines the rate at
which depreciation may be charged for various types of industrial facilities.

In the most widely used method of depreciation calculation (MACRS), the amount
of depreciation changes year by year.
Some definitions of profit
Gross profit before depreciation

The difference between the income from sales(si ) and operating costs(Co ) is the gross
profit before depreciation charge = si – co

Gross profit after depreciation

Gross profit after depreciation(G2) =si – coj- dj

Net Profit Income tax = ɸ (si – coj - dj)

Net Profit=G2 - income tax Income tax : 30-35% of G2

Net flow back to the reservoir ɸ : Fixed income tax rate

Aj = (si – coj - dj) (1- ɸ) + ɸ dj0

Example : if revenue from sales =100 and Operation cost is 20 and

Depreciation is 10 then

Gross profit= 100-20= 80

Gross profit after depreciation 80-10=70, income tax =70 *0.3=21
net profit after tax => 70-21=49
Financing

Interest is considered to be the compensation paid for the use of borrowed capital.

A fixed rate of interest is established at the time the capital is borrowed; therefore,
interest is a definite cost if it is necessary to borrow the capital used to make the
investment for a plant.

Although the interest on borrowed capital is a fixed charge, there are many persons who
claim that interest should not be considered as a manufacturing cost, but that it should
be listed as a separate expense under the general heading of management or financing
cost.

Local Taxes

The magnitude of local property taxes depends on the particular locality of the plant
and the regional laws.

Annual property taxes for plants in highly populated areas are ordinarily in the range of
2 to 4 percent of the fixed-capital investment.

In less populated areas, local property taxes are about 1 to 2 percent of the fixed-
capital investment.
Property Insurance

Insurance rates depend on the type of process being carried out in the manufacturing
operation and on the extent of available protection facilities. These rates amount to
about 1 percent of the fixed-capital investment per year.

Rent

Annual costs for rented land and buildings amount to about 8 to 12 percent of
the value of the rented property.

In preliminary estimates, rent is usually not included

The costs component of manufacturing cost discussed so far are directly related to
the production operation.

Many other expenses are always involved if the complete

plant is to function as an efficient unit
 Plant Overhead Costs

The expenditures required for routine plant services are included in plant overhead costs.
Nonmanufacturing machinery, equipment, and buildings are necessary for many of the
general plant services,

Medical, Safety and protection, General plant overhead, Payroll overhead, Packaging,
Restaurant, Recreation, Control laboratories, Plant superintendence, Storage facilities

The fixed charges and direct costs for these items are part of the plant overhead costs.

These charges are closely related to the costs for all labor directly connected with the
production operation. The plant overhead cost for chemical plants is about 50 to 70 percent
of the total expenses for operating labor, supervision, and maintenance.
 General Expenses

In addition to the manufacturing costs, other general expenses are involved in the
operations of a company.
These general expenses may be classified as
(1) Administrative expenses
(2) Distribution and marketing expenses
(3) Research and development expenses

Administrative Costs
The expenses connected with executive and administrative activities

Salaries and wages for administrators, secretaries, accountants, computer support staff,
engineering, and legal personnel etc.

Costs for office supplies and equipment, outside communications, administrative

buildings, and other overhead items related to administrative activities.

The administrative costs may be approximated as 15 to 25 percent of operating labor.

 Distribution and Marketing Costs

No manufacturing operation can be considered a success until the products

have been sold or put to some profitable use.

The general expenses are incurred in the process of selling and distributing
the various products are:

 Salaries, wages, supplies, and other expenses for sales offices

Traveling expenses for sales representatives

Shipping expenses
Cost of containers
Advertising expenses
Technical sales service
Distribution and marketing costs vary widely for different types of plants depending on the
particular material being produced , plant location, and company policies.

These costs for most chemical plants are in the range of 2 to 20 percent of the total product
cost.
The higher figure usually applies to a new product or to one sold in small quantities to a
large number of customers.

The lower figure applies to large-volume products, such as bulk chemicals.

Research and Development Costs

New methods and products are constantly being developed in the chemical industries as a
result of research and development.

Any progressive company that wishes to remain in a competitive industrial position incurs
research and development expenses.

• Research and development costs include:

1. Salaries and wages for all personnel

2. Fixed and operating expenses for all machinery
and equipment
3. Costs for materials and supplies, and
consultants' fees.
 •In some industries, such as pharmaceuticals, research may be the largest
component of the total product cost.

• In the chemical industry, these costs amount to about 5 percent of total product
cost.

CONTINGENCIES

Unforeseen events, such as strikes, storms, floods, price variations, and other
contingencies, may have an effect on the costs for a manufacturing operation
07 9 21
38,43 92,95,96
 10 9 21
Summary of the cost estimation

We started with Classification of Capital investment Discussed about Cash

flow analysis •Cash flow by tree diagram
•Cumulative cash flow diagram
•Factors affecting capital investment
• source of equipment
•Price fluctuations
•Company policies
•Operating time and rate of production
•Government policies

Estimation of Capital investment

Types of capital investment

•Order of magnitude estimate

•Study estimate
•Preliminary estimate (budget authorization estimate or
scope estimate)
•Definitive estimate (project control estimate)
•Detailed estimate (contractor's estimate)
Cont…..
COST INDEXES

•Marshall and Swift installed-equipment indexes

•Nelson-Farrar refinery construction
•Chemical Engineering plant cost index
•Eng. News-Record construction index

•Indian Construction cost index CIDC in 1998 was 100

•Whole sale price index WPI for machinery and equipment by Ministry of Commerce
and Industry
•Railway serive price index
•Postal service price index WPI for Machinery and Equipment
•Banking service price index FY 2013 103.6
•Air service price index FY 2019 111.3
•Port service price index
•Insurance service price index
Fixed-capital investment for multipurpose plants or large additions to existing facilities

Direct costs Indirect costs

1. Purchased equipment 15-40 1. Engineering and supervision 4-20
2. Purchased-equipment installation 6-14 2. Construction expenses 4-17
3. Instrumentation and controls (installed) 3. Legal expenses 1-3
2-12 4. Contractor's fee 2-6
4. Piping (installed) 4-17 5. Contingency 5-15
5. Electrical systems (installed) 2-10
6. Buildings (including services) 2-18
7. Yard improvements 2-5 Grass-roots plants: A complete plant
8. Service facilities (installed) 8-30 erected on a new site.
9. Land 1-2
Large battery limit
 Estimating Equipment Costs by Scaling

Six-tenths factor rule

Cost of equipment of X times capacity = (cost of equipment)X0.6

METHODS FOR ESTIMATING CAPITAL INVESTMENT

We have discussed Seven methods

Method A: Detailed-Item Estimate

Method B: Unit Cost Estimate
Method C: Percentage of Delivered-Equipment Cost
Method D: Lang Factors for Approximation of Capital Investment
Method E: Power Factor Applied to Plant/Capacity Ratio
Method F: Investment Cost per Unit of Capacity
Method G: Turnover Ratio

The choice of any one method depends upon the amount of detailed information
available and the accuracy desired.
Summary Cont…

ESTIMATION OF REVENUE

ESTIMATION OF TOTAL PRODUCT COST

TOTAL PRODUCT COST = costs of operating the plant+ selling the products + recovering
the capital investment + contributing to corporate functions such as management and
research and development.

TOTAL PRODUCT COST = Manufacturing costs + General expenses

Manufacturing costs are also referred to as operating or production costs

Manufacturing Costs= Variable Production cost + Fixed charges + Plant

overhead costs

General expenses= Administrative expenses+ Distribution and marketing

expenses+ Research and development
Problem 1
The purchased and installation costs of some pieces of equipment are given as a
function of weight rather than capacity. An example of this is the installed costs
of large tanks. The 1990 cost for an installed aluminum tank weighing 45,000 kg
was $640,000. For a size range from 90,000 to 450,000 kg, the installed cost
weight exponent for aluminum tanks is 0.93. If an aluminum tank weighing
300,000 kg is required, what capital investment is needed in the year 2000?

Problem 2
The 1990 cost for an installed 304 stainless steel tank weighing 135.000 kg was
$1,100,000. The installed cost weight exponent for stainless steel tanks is 0.88 for
a size range from 100,000 to 300,000 kg. What weight of installed stainless steel
tank could have been obtained for the same capital investment as in problem 1.

Problem 3
The purchased cost of equipment for a solid processing plant is $500,000. The
plant is to be constructed as an addition to an existing plant. Estimate the total
capital investment and the fixed-capital investment for the plant. What
percentage and amount of the fixed-capital investment are due to cost for
engineering and supervision, and what percentage and amount for the
contractor's fee?
Problem 4
The purchased-equipment cost for a plant which produces pentaerythritol (solid-fluid
processing plant) is $300,000. The plant is to be an addition to an existing formaldehyde
plant. The major part of the building cost will be for indoor construction. The
contractor's fee will be 7 percent of the direct plant cost. All other costs are close to the
average values found for typical chemical plants. On the basis of this information,
estimate the total direct plant cost, the fixed-capital investment, and the total capital
investment.

Problem 5
Estimate by the turnover ratio method the fixed-capital investment required in 2000 for
a proposed sulfuric acid plant (battery-limit) which has an annual capacity of 1.3 x 108
kg/yr of 100 percent sulfuric acid (contact-catalytic process), using the data from Table
6-11, when the selling price for the sulfuric acid is $86 per metric ton. The plant will
operate 325 days/year. Repeat the calculation, using the cost capacity exponent method
with data from Table 6-11. 6-10 The total capital investment for a chemical plant is $1
million, and the working capital is $100,000. If the plant can produce an average of 8000
kg of final product per day during a 365-day year, what selling price in dollars per
kilogram of product would be necessary to give a turnover ratio of 1.0?
 Depreciation

Depreciation: Decrease in the cost of service or equipment

Physical depreciation

Wear and tear corrosion , due to accident aging etc

Functional depreciation
Technological advancement
Decrease in demand of service rendered by the property ,
Shift in population abandonment of the enterprise ,
Change in public requirement
 Depreciable asset

Except land Eth is depreciable such as physical facility and Yard Improvement

Purpose of Depreciation
To ascertain the true profit of the business
To show the true presentation of financial positions
To provide fund for replacement of asset
To show the assets as its reasonable value in the balance sheet

Factor affecting the amount of depreciation

Original cost of the asset

The useful life of the asset
Estimated scrape value o the asset
Selecting an appropriate method of depreciation

Depreciation affect both profit and tax and therefore only those method recommended by the
Govt can be used to calculate the Depreciation
 Some Definitions

Current Value: Value at the time of evaluation

Service Life : the period over which the use of property is economically feasible

Book Value : difference between original cost of the property and all depreciation charge
up to a time

Salvage value : value of equipment after retirement

 24 9 21
28,31, 37,38,44,49
66,68,71,72,,74,92,95,101
Q.1 The purchased cost of a shell-and-tube heat exchanger (floating-head and
carbon-steel tubes) with 100 nr of heating surface was $4200 in 1990. What will
be the 1990 purchased cost of a similar heal exchanger with 20 m2 of heating
surface if the purchased cost capacity exponent is 0.60 for surface areas ranging
from 10 to 40 m2? If the purchased cost capacity exponent for this type of
exchanger is 0.81 for surface areas ranging from 40 to 200 nr, what will be the
purchased cost of a heat exchanger with 100 nr of heating surface in 2000?
The total capital investment for a chemical plant is $1 million, and the working
capital is $100,000. If the plant can produce an average of 8000 kg of final
product per day during a 365-day year, what selling price in dollars per kilogram
of product would be necessary to give a turnover ratio of 1.0?
A process plant making 5000 kg/day of a product selling for $1.75/kg has annual
variable production costs of $2 million at 100 percent capacity and fixed costs
of $700,000. What is the fixed cost per kilogram at the breakeven point? If the
selling price of the product is increased by 10 percent, what is the dollar
increase in net profit at full capacity if the income tax rate is 35 percent of gross
earnings?
A new storage tank can be purchased and installed for $10,000. The estimated
service life of this tank is 10 years. It has been proposed that an available tank with
the capacity equivalent to the new tank be used instead of buying the new tank. If
the latter tank were repaired, it would have a service life of 3 years before similar
repairs would be needed again. Neither tank has any scrap value. Money is worth 6
percent compounded annually. On the basis of equal capitalized costs for the two
tanks, how much can be spent for repairing the existing
tank?
Profitability, Alternative Investments, and Replacements
  A new project, such as constructing and operating
a new chemical plant, requires a commitment of
capital funds

Earning a rewarding profit is perhaps the most

important factors to decided the investment.
Other factors weighing into such a decision include :
Availability of capital
Market position
health, safety, and environmental concerns
A proposed investment must be evaluated for its economic
feasibility

1. Design study must be carried out

2. The design study produces specifications from which cost estimates can be made
3. These cost estimates, in turn, become the data for evaluating the economic
consequences of the project.

Design study Specifications Cost estimates Economic consequences

PROFITABILITY STANDARDS

A profitability standard is a quantitative measure of profit with respect to the

investment required to generate that profit.

Profit is the goal of any investment,

maximizing profit is an inadequate profitability standard. The profit must be judged
relative to the investment.

For example
Two equally sound investment opportunities are available. One of these requires a $
100,000 capital investment and will yield a profit of $ 10,000 per year, while the
second requires $1 million of capital investment and will yield a profit of $25,000 per
year.

While the second investment provides a greater yearly profit than the first, the
annual rate of return on that investment is only ($25,000/$l,000,000)(100), or 2.5
percent, while it is 10 percent for the first investment. If
PROFITABILITY STANDARDS

1. Cost of Capital

Any project must earn at least that rate just to repay these external capital sources

2. Minimum Acceptable Rate of Return Or minimum attractive rate of return, or MARR)

The minimum acceptable rate of return (mar) is a rate of earning that must be achieved
by an investment in order for it to be acceptable to the investor.

The mar generally is based on the highest rate of earning on safe investments that is
available to the investor, such as corporate bonds, government bonds, and loans.

Cost of Capital Establish MARR Adjust MARR with risk associated

with other investment

Commensurate MARR with risk

MARR and risk table
 METHODS FOR CALCULATING PROFITABILITY

A. The methods that do not consider the time value of money include

Rate of Return on Investment,

Payback Period,

Net return..

B. The methods that consider the time value of money involve

Discounted Cash Flow Rate of Return

Net Present Worth

Return on Investment (ROI)

This profitability measure is defined as the ratio of profit to investment. Although any
of several measures of profit and investment can be used, the most common are net
profit and total capital investment.

Np the annual net profit, and T the total capital investment.

Gross profit, before income taxes, or cash fiw is sometimes used in place of net
profit. Fixed-capital investment can be used rather than total investment.
 Net profit usually is not constant from year to year for a project; total investment
also changes if additional investments are made during project operation.

An ROI calculated can be compared directly with a mar value supplied or selected from
Table 8-1.

 If the ROI equals or exceeds the minimum acceptable rate of return mar, then the
project offers an acceptable rate of return.

 If it does not, then the conclusion is that the project is not desirable for the
investment of either borrowed or corporate funds.
 Payback Period

Payout period is the length of time necessary for the total return to equal the capital
investment.

The initial fixed-capital investment and annual cash flw are usually used in this calculation,

where PBP is the payback period in years,

V is the manufacturing fixed-capital investment,

Ax the nonmanufacturing fixed-capital investment,

V + Ax is the fixed-capital investment, and Aj the annual cash flow

This PBP represents the time required for the cash flow to equal the original fixed-capital
investment
It is subject to the fact that the cash flow usually changes from year to year,
thereby raising the question of which annual values to use.

V + Ax is approximately equal to and (Aj)ave is equal to Np

Absent no. 8,14,23,28,42,43

62,63,79,93,95,96,101
Standard and special equipment

From selection considerations the equipment's are classified as

a) Standard equipment's.
b) Special equipment's.

Though there is no difference between these two but a equipment is common in

use is called standard equipment while other is called special equipment.
Standard Equipments
These are designed to meet the wide demand of the equipment users and to sell in
large quantities at comparatively low prices.

A standard machine is the result of years of experience and therefore has

considerable reliability in the operation.

A standard machine performs at fairly great difference in output and speed.

Availability and delivery of these are easy and fast and unit cost of production is less.

These are manufactured commonly and easily available from the dealers.
Special Equipments
These are generally manufactured to perform specialized operations. Such equipment's
results in low wage cost and low capital costs per unit of output, when the plant
operates at high capacity.

The equipment size of such equipment is comparatively high and there is the risk of loss
of investment in the equipment when radical design changes occur or the character of
the demand changes.

Availability and delivery of these equipment's is difficult and delayed.

Special order has to be placed to get such equipment. These are fabricated as per
requirement.

Unit cost of production is high.

The equipment used in the chemical processes industries can be divided into two
classes:

Proprietary
Nonproprietary

Proprietary equipment, such as pumps, compressors, filters, centrifuges and dryers,

is designed and manufactured by specialist firms.

Nonproprietary equipment is designed as special, one-off items for particular

processes, for example, reactors, distillation columns, and heat exchangers.
Something important to know

Unless employed by one of the specialist equipment manufacturers, the chemical

engineer is not normally involved in the detailed design of proprietary equipment.

The chemical engineer's job will be to select and specify the equipment needed for a
particular duty; consulting with the vendors to ensure that the equipment supplied is
suitable.

Chemical engineers may be involved with the vendor's designers in modifying

standard equipment for particular applications; for example, a standard tunnel dryer
designed to handle particulate solids may be adapted to dry synthetic fibers.
 Many factors have to be considered when selecting engineering materials, but for
chemical process plant the overriding consideration is usually the ability to resist
corrosion

The material selected must have sufficient strength and be easily worked.

The most economical material that satisfies both process and mechanical requirements
should be selected;

This will be the material that gives the lowest cost over the working life of the plant,
allowing for maintenance and replacement.
Mechanical properties that are important in the selection of materials:

The most important characteristics to be considered when selecting a material of

construction are:
1. Mechanical properties
(a) Strength tensile strength
(b) Stiffness elastic modulus (Young’s modulus)
(c) Toughness fracture resistance
(d) Hardness wear resistance
(e) Fatigue resistance
(f) Creep resistance

2. The effect of high and low temperatures on the mechanical properties

3. Corrosion resistance
4. Any special properties required; such as, thermal conductivity, electrical resistance,
magnetic properties
5. Ease of fabrication forming, welding, casting
6. Availability in standard sizes plates.
7. Cost
Tensile strength

The tensile strength (tensile stress) is a measure of the basic strength of a material. It is
the maximum stress that the material will withstand, measured by a standard tensile test.

Stiffness

Stiffness is the ability to resist bending and buckling. It is a function of the elastic modulus
of the material and the shape of the cross-section of the member (the second moment of
area)

Toughness

Toughness is associated with tensile strength, and is a measure of the material’s

resistance to crack propagation.

Hardness

Hardness The surface hardness, as measured in a standard test, is an indication of a

material’s ability to resist wear.
 Fatigue

Fatigue failure is likely to occur in equipment subject to cyclic loading; for example,
rotating equipment, such as pumps and compressors, and equipment subjected to
pressure cycling.

Creep

Creep is the gradual extension of a material under a steady tensile stress, over a
prolonged period of time. It is usually only important at high temperatures; for
instance, with steam and gas turbine blades.

Effect of temperature on the mechanical properties

The tensile strength and elastic modulus of metals decrease with increasing temperature.

For example, the tensile strength of mild steel (low carbon steel, C < 0.25 per cent) is 450
N/mm2 at 25oC falling to 210 at 500oC, and the value of Young’s modulus 200,000 N/mm2
at 25oC falling to 150,000 N/mm2 at 500oC.
 Change in Properties of Material with Change in Temperature

At low temperatures, less than 10oC, metals that are normally ductile can fail in a brittle
manner.

Serious disasters have occurred through the failure of welded carbon steel vessels at low
temperatures.

The phenomenon of brittle failure is associated with the crystalline structure of metals.

Metals with a body-centred-cubic (bcc) lattice are more liable to brittle failure than those
with a face-centred-cubic (fcc) or hexagonal lattice.

For low-temperature equipment, such as cryogenic plant and liquefied-gas storages,

austenitic stainless steel (fcc) or aluminium alloys (hex) should be specified
Classification of corrosion
1. General wastage of material uniform corrosion.
2. Galvanic corrosion dissimilar metals in contact.
3. Pitting localised attack.
4. Intergranular corrosion.
5. Stress corrosion.
6. Erosion corrosion.
7. Corrosion fatigue.
8. High temperature oxidation.
9. Hydrogen embrittlement.
Galvanic Corrosion

If dissimilar metals are placed in contact, in an electrolyte, the corrosion rate of the anodic
metal will be increased, as the metal lower in the electrochemical series will readily act as a
cathode.

Pitting

Pitting is the term given to very localised corrosion that forms pits in the metal surface

Intergranular corrosion

Intergranular corrosion is the preferential corrosion of material at the grain (crystal)

boundaries.

Effect of stress on corrosion

Corrosion rate and the form of attack can be changed if the material is under stress.
Generally, the rate of attack will not change significantly within normal design stress
values.
 High-temperature oxidation

 Corrosion is normally associated with aqueous solutions but oxidation can occur in dry
conditions.

Carbon and low alloy steels will oxidise rapidly at high temperatures and their use is
limited to temperatures below 500oC.

Chromium is the most effective alloying element to give resistance to oxidation, forming
a tenacious oxide film.

Chromium alloys should be specified for equipment subject to temperatures above 500oC
in oxidizing atmospheres.
Hydrogen Embrittlement

Hydrogen embrittlement is the name given to the loss of ductility caused by the
absorption (and reaction) of hydrogen in a metal.

It is of particular importance when specifying steels for use in hydrogen reforming
plant.

Alloy steels have a greater resistance to hydrogen embrittlement than the plain
carbon steels.
 Selection for Corrosion Resistance material

In order to select the correct material of construction, the process environment to which the
material will be exposed must be clearly defined.

Additional to the main corrosive chemicals present, the following factors must be considered:

1. Temperature affects corrosion rate and mechanical properties.

2. Pressure.
3. pH.
4. Presence of trace impurities stress corrosion.
5. The amount of aeration differential oxidation cells.
6. Stream velocity and agitation erosion-corrosion.
7. Heat-transfer rates differential temperatures.
8. The conditions that may arise during abnormal operation, such as at start-up and
shutdown, must be considered, in addition to normal, steady state, operation.
Ferrous Metals and Alloys

Non Ferrous Metals and Alloys

Inorganic Nonmetals

Organic Nonmetals
Ferrous Metals and Alloys
Pig iron : Pig iron is the product of smelting iron ore

Wrought iron

Cost Iron

Gray Cast Iron

White cast Iron

Alloy cost Iron

High Silicon Iron

High Silicon Iron with Mb

Steel : Fe+ C (0.05 %- 2.0%) +S+Si+Mn

Low Steel /Mild Steel 0.05 %-0.3% C

Medium carbon steel : 0.3% to 0.5% C

High Carbon Steel : C 0.5%to 1%
Alloy steel

Ni : Corrosion and High temperature resistance

Cr : Corrosion and High temperature resistance
Si:
Mn : Abrasion resistance and tough iron
Mo: adds corrosion resistance and high temperature strength
W: to improve the cutting efficiency, hardness, and speed of tools
Be:
V: During the heat treatment of steel, vanadium addition can increase its ability to
temper and increase the hardness of high-speed steel

Co: increases hardness and promotes greater wear resistance

Ti: tantalum increases the ductility, strength and melting point of steel
Si/ Mn: Elasticity

Ni/Cr/Ti: Creep Resistance

Low Alloy steel

Small % (<10)of Ni , Cr, Mo, Mn,

High alloy steel

1. Straight Cr steel Cr 13-17%

C: 0.08% Plates
C: 0.1%: Forging
C: 0.2% : casting
C: 0.15% : Bolting

1. Cr-Ni-steel : Stainless steel : Cr: 18-25% ,, Ni 8%- 20% C: 0.03-0.25%

 The general mechanical properties, corrosion resistance, and typical areas of use of
some of the materials commonly used in the construction of chemical plant

The multitude of alloys used in chemical plant construction is known by a variety of trade
names, and code numbers designated in the various national standards.

1. Iron and steel

Low carbon steel (mild steel) is the most commonly used engineering material.

It is cheap; is available in a wide range of standard forms and sizes; and can be easily
worked and welded.

It has good tensile strength and ductility.

The carbon steels and iron are not resistant to corrosion, except in certain specific
environments, such as concentrated sulphuric acid and the caustic alkalies. ‘

They are suitable for use with most organic solvents, except chlorinated solvents; but traces
of corrosion products may cause discoloration.
2. Stainless steel

The stainless steels are the most frequently used corrosion resistant materials in the
chemical industry.
There are more than 70 standard types of stainless steel and many special alloys.

 To impart corrosion resistance the chromium content must be above 12 per cent, and
the higher the chromium content, the more resistant is the alloy to corrosion in oxidizing
conditions.

Nickel is added to improve the corrosion resistance in non-oxidizng environments.

Types

They can be divided into three broad classes according to their microstructure:

1. Ferritic: 13- 20 per cent Cr, < 0.1 per cent C, with no nickel

2. Austenitic: 18- 20 per cent Cr, > 7 per cent Ni

3. Martensitic: 12 -10 per cent Cr, 0.2 to 0.4 per cent C, up to 2 per cent Ni
The uniform structure of Austenite (fcc, with the carbides in solution) is the structure
desired for corrosion resistance, and it is these grades that are widely used in the chemical
industry.

Type 304, Type 304L, Type 321, Type 347, Type 316, Type 316L,

Mechanical properties

The austenitic stainless steels have greater strength than the plain carbon steels,
particularly at elevated temperatures

The austenitic stainless steels, unlike the plain carbon steels, do not become brittle at low
temperatures.
High alloy content stainless steels

Super austenitic, high nickel, stainless steels, containing between 29 to 30 per cent nickel
and 20 per cent chromium, have a good resistance to acids and acid chlorides.

They are more expensive than the lower alloy content, 300 series, of austenitic stainless
steels.

Duplex, and super-duplex stainless steels, contain high percentages of chromium.

They are called duplex because their structure is a mixture of the austenitic and ferritic
phases.

They have a better corrosion resistance than the austenitic stainless steels and are less
susceptible to stress corrosion cracking.

The chromium content of duplex stainless steels is around 20 per cent, and around 25 per
cent in the super-duplex grades.

The super-duplex steels where developed for use in aggressive off-shore environments
Nickel

 Nickel has good mechanical properties and is easily worked.

The pure metal (>99 per cent) is not generally used for chemical plant,
Its alloys being preferred for most applications.

The main use is for equipment handling caustic alkalies at temperatures above that at
which carbon steel could be used; above 70oC.

 Nickel is not subject to corrosion cracking like stainless steel.

Monel

Monel, the nickel-copper alloy with the metals in the ratio 2 : 1, is probably, after the
stainless steels, the most commonly used alloy for chemical plant.

 It is easily worked and has good mechanical properties up to 500oC.

It is more expensive than stainless steel but is not susceptible to stress-corrosion
cracking in chloride solutions.

 Monel has good resistance to dilute mineral acids and can be used in reducing
conditions, where the stainless steels would be unsuitable.

It may be used for equipment handling, alkalies, organic acids and salts, and sea
water
Nonferrous Metals and Alloys
Inconel

Inconel (typically 76 per cent Ni, 7 per cent Fe, 15 per cent Cr) is used primarily for acid
resistance at high temperatures. It maintains its strength at elevated temperature and is
resistant to furnace gases, if sulphur free.

The Hastelloys

The trade name Hastelloy covers a range of nickel, chromium, molybdenum, iron alloys
that were developed for corrosion resistance to strong mineral acids, particularly HCl.

The corrosion resistance, and use, of the two main grades,

Hastelloy B (65 per cent Ni, 28 per cent Mo, 6 per cent Fe)

Hastelloy C (54 per cent Ni, 17 per cent Mo, 15 per cent Cr, 5 per cent Fe),
Copper and Copper Alloys

Pure copper is not widely used for chemical equipment.

It has been used traditionally in the food industry, particularly in brewing.

Copper is a relatively soft, very easily worked metal, and is used extensively for small-bore
pipes and tubes.
The main alloys of copper are
Brasses, alloyed with zinc
Bronzes, alloyed with tin

Copper is attacked by mineral acids, except cold, dilute, unaerated sulphuric acid.

It is resistant to caustic alkalies, except ammonia, and to many organic acids and salts.

The brasses and bronzes have a similar corrosion resistance to the pure metal.

Their main use in the chemical industry is for valves and other small fittings, and for heat-
exchanger tubes and tube sheets.
Aluminium and its alloys

Pure aluminium lacks mechanical strength but has higher resistance to corrosion than its
alloys.

The main structural alloys used are the Duralumin (Dural) range of aluminium-copper.
alloys (typical composition 4 per cent Cu, with 0.5 per cent Mg).

The pure metal can be used as a cladding on Dural plates, to combine the corrosion
resistance of the pure metal with the strength of the alloy.

The corrosion resistance of aluminium is due to the formation of a thin oxide film (as with
the stainless steels). It is therefore most suitable for use in strong oxidising conditions.

It is attacked by mineral acids, and by alkalies; but is suitable for concentrated nitric acid,
greater than 80 per cent.

It is widely used in the textile and food industries,

It is also used for the storage and distribution of demineralised water.
Lead and Alloys

Pure lead has low creep and fatigue resistance, but its physical properties can be improved
by the addition of small amounts of silver, copper, antimony, or tellurium.

The excellent corrosion resistance properties of lead are caused by the formation of
protective surface coatings.

If the coating is one of the highly insoluble lead salts, such as sulfate, carbonate, or
phosphate, good corrosion resistance is obtained.

Little protection is offered, however, if the coating is a soluble salt, such as nitrate, acetate,
or chloride.

Lead shows good resistance to sulfuric acid and phosphoric acid, but is susceptible to attack
by either acetic or nitric acid.
 Inorganic Nonmetals

Glass, stoneware, brick, and cement materials are common examples of inorganic
nonmetals used as materials of construction.

Low structural strength.

They are often used in the form of linings or coatings bonded to metal supports.

For example, glass-lined equipment has many applications in the chemical industries.

Glass and Glassed Steel

Glass has excellent resistance and is subject to attack only by hydrofloric acid and hot
alkaline solutions.

It is particularly suitable for processes which have critical contamination levels.

A disadvantage is its brittleness and damage by thermal shock.

 Stoneware and Porcelain

Materials of stoneware and porcelain are about as resistant to acids and chemicals as
glass, but with the advantage of greater strength.

Porcelain enamels are used to coat steel

Brick and Cement Materials

Brick-lined construction can be used for many severely corrosive conditions, where
high alloys would fail.

Acid-proof refractories can be used up to 9000C.

 Organic Nonmetals

In comparison with metallic materials, the use of organic non-metallics is limited to

relatively moderate temperatures and pressures.

Plastics, for example, are less resistant to mechanical abuse and have high expansion
rates, low strengths (thermoplastics), and only fair resistance to solvents.

Desirable properties of Organic Nonmaterial's : they are lightweight, are good thermal
and electrical insulators, are easy to fabricate and install, and have low friction factors.

Plastics
plastics have excellent resistance to weak mineral acids and are
unaffected by inorganic salt solutions—areas where metals are not entirely
suitable.

Since plastics do not corrode in the electrochemical sense, they offer another
advantage over metals: Most metals are affected by slight changes in pH, minor
impurities, or oxygen content, while plastics will remain resistant to these same
changes.
 Tetrafloroethylene (TFE)

One of the most chemical-resistant plastic commercially available today is

tetrafloroethylene, orTFE (Tefin).

This thermoplastic is practically unaffected by all alkalies and acids except florine and
chlorine gas at elevated temperatures and molten metals

It retains its properties up to 260C.

Chlorotrifloroethylene:

CTFE (Kel-F) also possesses excellent corrosion resistance to almost all acids and alkalies up
to 175C.
 FEP

FEP a copolymer of tetraflorethylene and hexafloropropylene, has similar properties to

TFE except that it is not recommended for continuous exposures at temperatures above
200C.

FEP can be extruded on conventional extrusion equipment, while TFE parts must be
fabricated by complicated powdered-metallurgy techniques.

Polyvinylidene floride:

Polyvinylidene floride, or PVF2 (Kynar), has excellent resistance to alkalies and acids to 150oC.

Perfloroalkoxy

Perfloroalkoxy , or PFA, on the other hand, can tolerate temperatures up to 300oC while
exhibiting the general properties and chemical resistance of FEP.
Unplasticized polyvinyl chlorides

Unplasticized polyvinyl chlorides (type I) have excellent resistance to oxidizing acids

except when concentrated, and to most nonoxidizing acids.

Resistance is also good when exposed to weak and strong alkaline solutions.

Resistance to chlorinated hydrocarbons is not good, but can be greatly improved with the
substitution of a polyvinylidene known as Saran.

Acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene (ABS) polymers have good resistance to nonoxidizing

and weak acids but are not satisfactory with oxidizing acids.

Upper temperature limit is about 65C. Resistance to weak alkaline solutions is excellent.

They are not satisfactory with aromatic or chlorinated hydrocarbons but have good
resistance to aliphatic hydrocarbons.
Acetals

Acetals have excellent resistance to most organic solvents but are not satisfactory for
use with strong acids and alkalies.

Polypropylene
The chemical resistance of polypropylene is about the same as that of polyethylene, but
it can be used at 120C.

Polyphenylene sulfide

Polyamide
 Thermosetting materials

Phenolic plastics
Among the thermosetting materials are phenolic plastics filled with carbon, graphite,
and silica.

Relatively low cost, good mechanical properties, and chemical resistance (except against
strong alkalies) make phenolics popular for chemical equipment.

Furan plastics
Furan plastics, filled with asbestos, have much better alkali resistance than phenolic
asbestos. They are more expensive than the phenolics but also offer somewhat
higher strengths.
 Composite material

Polyester resins, reinforced with fiberglass

General-purpose polyester resins, reinforced with fiberglass, have good strength and
good chemical resistance, except to alkalies.

Some special materials in this class, based on bisphenol, are more alkali-resistant.
Temperature limit for polyesters is 95C.

Epoxies reinforced with fiberglass

Epoxies reinforced with fiberglass have very high strengths and resistance to heat.

Chemical resistance of the epoxy resin is excellent in nonoxidizing and weak acids
but poor with strong acids.
Rubber and Elastomers

Natural and synthetic rubbers are used as linings or as structural components for
equipment in the chemical industries.

By adding the proper ingredients, natural rubbers with varying degrees of hardness and
chemical resistance can be produced.

Hard rubbers are chemically saturated with sulfur.

The vulcanized products are rigid and exhibit excellent resistance to chemical attack by
dilute sulfuric acid and dilute hydrochloric acid.
Natural rubber is resistant to dilute mineral acids, alkalies, and salts; but oxidizing
media, oils, benzene, and ketones will attack it.

Chloroprene or neoprene rubber is resistant to attack by ozone, sunlight, oils,

gasoline, and aromatic or halogenated solvents.

Styrene rubber has chemical resistance similar to that of natural rubber.

Nitrile rubber is known for resistance to oils and solvents.

Butyl rubber's resistance to dilute mineral acids and alkalies is exceptional;

resistance to concentrated acids, except nitric and sulfuric, is good.

Silicone rubbers, also known as polysiloxanes, have outstanding resistance to high

and low temperatures as well as against aliphatic solvents, oils, and greases.
Carbon and Graphite

Generally, impervious graphite is completely inert to all but the most severe oxidizing
conditions.

This property, combined with excellent heat transfer, has made impervious carbon
and graphite very popular in heat exchangers, as brick lining, and in pipe and pump
systems.

One limitation of these materials is low tensile strength.

Threshold oxidation temperatures are 350oC for carbon and 400oC for graphite.
1. Identifeition
2. Function
3. Operation
4. Materials handled
5. Design data
6. Utilities
7. Controls
8. Insulation
9. Tolerances
10.Comments and drawings
 Optimum Design and Design Strategy

The factors affecting the economic performance of the design include

The types of processing technique used
Processing equipment used
Arrangement and sequencing of the processing equipment used in the design
The actual physical parameters for the equipment
The operating conditions for the equipment are of prime concern and import.

In engineering process design, the criteria for optimality can ultimately be reduced to a
consideration of costs or profits.
When a design variable is changed, often some costs increase and others decrease.

“Under these conditions, the total cost may go through a minimum at one value of the
particular design variable, and this value is the optimum value of that variable.”

An example illustrating the principles

of an optimum economic design is
 DEFINING THE OPTIMIZATION PROBLEM

A. Optimum design analysis begins with the establishment of the optimization task.

B. This requires the selection of an economic criterion that is to be the objective

function.
C. Next, the process is examined to determine variables and constraints that affect
process performance and the objective function.

Once the optimization basis is determined, it is necessary to determine process

variables in the design that is to be optimized.

Process variables are the variables that affect the values of the objective functions.

The process variables are scrutinized and divided into decision and dependent
variables.
The following equation shows the effect of the variables x and y on the
total cost for a particular operation:

Determine the values of x and y that will give the least total cost.
 The investment for piping and pipe fittings can amount to an important part of the
total investment for a chemical plant.

For any given set of flow conditions, the use of an increased pipe diameter will cause
an increase in the fixed charges for the piping system and a decrease in the pumping
charges.

Pumping Costs

For any given operating conditions involving the flow of an incompressible fluid through
a pipe of constant diameter, the total mechanical energy balance
The annual pumping cost when the flow is turbulent
Fixed Charges for Piping System

For most types of pipe, the purchase cost for pipe may be represented by

Optimum Economic Pipe Diameter

Page no 405
 Selection of Reactors

The selection of the best reactor type for a given process is subject to a number of
major considerations.

(1) Temperature and pressure of the reaction;

(2) Need for removal or addition of reactants and products;
(3) Required pattern of product delivery (continuous or batchwise);

(4) Catalyst use considerations, such as the requirement for solid catalyst particle
replacement and contact with fluid reactants and products;

(5) Relative cost of the reactor

(6) Limitations of reactor types as discussed in the previous section. Other considerations
such as available space, safety, and related factors can be important and should not be
overlooked.
The explicit guidelines for reactor selection are not available, there are some general
rules of thumb that can be followed in the selection process of an appropriate reactor for
a given reaction.

These are briefly summarized here:

1. For conversions up to 95 percent of equilibrium the performance of five or more CSTRs

connected in series approaches that of a PER.

2. CSTRs are usually used for slow liquid-phase or slurry reactions.

3. Batch reactors are best suited for small-scale production, very slow reactions, those which
foul, or those requiring intensive monitoring or control.

4. The typical size of catalytic particles is approximately 0.003 m for fixed-bed reactors,
0.001 m for slurry reactors, and 0.0001 m for fluidized-bed reactors.

5. Larger pores in catalytic particles favor faster, lower-order reactions; conversely, smaller
pores favor slower, higher-order reactions.
Heat-Transfer Equipment
 PIPING IN FLUID TRANSPORT PROCESSES

The American National Standards Institute (ANSI) and the American Petroleum Institute
(API) have established detailed standards for the most widely used components of
piping systems. Lists of these standards as well as specifications for pipe and fitting
materials can be found in the ANSI B31 code sections.

Iron and steel pipes are specifiy according to wall thickness by a standard formula for
schedule number as designated by the American Standards Association (ASA)
 Selection of Piping Materials

General aspects that need to be evaluated when selecting piping materials are

(1) Possible exposure to fire with respect to the loss in strength or combustibility of the pipe
and supports

(2) Susceptibility of the pipe to brittle failure or thermal shock failure when exposed to fire

(3) Ability of thermal insulation to protect the pipe from fire

(4) Susceptibility of the pipe and joints to corrosion or adverse electrolytic effect

(5) Suitability of packing, seals, gaskets, and lubricants used on joints and connections

(6) Refrigeration effect during sudden loss of pressure with volatile fluids

(7) Compatibility with the fluid handled.

 The schedule number is defined by the ASA as the approximate value of

where Ss is the safe working stress and ps the safe working pressure, defined by

Here t is the minimum wall thickness in m, Dm the mean diameter in m, and Ps and Ss
in kPa.

For temperatures up to 120oC, the recommended safe working stress is 62,000 kPa for
lap-welded steel pipe and 49,000 kPa for butt-welded steel pipe.

Thus, if the schedule number is known, the safe working pressure can be estimated
directly
 Pipe sizes

Pipe sizes are based on the approximate diameter and are reported as nominal pipe
sizes.

Although the wall thickness varies depending on the schedule number, the outside
diameter of any pipe having a given nominal size is constant and independent of the
schedule number.

This permits the use of standard fittings and threading tools on pipes of different
schedule numbers.

Tubing specifications are based on the actual outside diameter with a designated wall
thickness. Conventional systems, such as the Birmingham wire gauge (BWG), are used
to indicate the wall thickness.
Pipe auxiliaries

Threaded fittings, flanges, valves, flowmeters, steam traps, and many other
auxiliaries are used in piping systems to connect sections of pipe, change the
directions of flow, or obtain desired conditions in a flow system.

 Flanges are usually employed for piping connections when the pipe diameter is
0.075 m or larger,

While screwed fittings are commonly used for smaller sizes.

 In the case of cast-iron pipe used as underground water lines, bell-and-spigot

joints are ordinarily employed rather than flanges.
The auxiliaries in piping systems must have sufficient structural strength to resist
the pressure or other strains encountered in the operation, and the design
engineer should provide a wide safety margin when specifying the ratings of these
auxiliaries.

Fittings, valves, steam traps, and similar items are often rated on the basis of safe
operating pressure.
 Piping support

Piping support plays a very crucial role in the proper functioning

of the piping systems.

Pipe support carries the pipe weight with contents.

To maintain the integrity of the piping system

Piping Loads

Piping Loads generated due to Weight, Pressure, Temperature, or Occasional Event

has to be transmitted from pipe to supporting structures with the help of
appropriate pipe supports.

Proper pipe support knowledge during the layout stage is advantageous.

Difference between Pipe Support and Pipe Restraint

Pipe supports are used to support the piping system by carrying the vertical
load whereas pipe restraints limit the movements of the pipe so take care of
the horizontal loads.

Simple Rest is pipe support but Guide and line stops are pipe restraints.

All pipe restraints come in combination with piping supports.

Pipe support and restraints combinedly can be said pipe support systems.
Purpose or Functions of piping support

The various functions that pipe support serves are as follows:

To prevent Pipe stresses in excess to allowable.

To eliminate the Leakages in joints.
To absorb Excessive Line Vibrations.
To counter the undesirable effects of Seismic, wind, water hammer, slug, and other
dynamic loadings.
To remove unintentional disengagement (lift-off) of piping from its supports.
To prevent excessive pipe sag (Normally more than 10 mm for process piping and 2.5
mm for power piping; 12.5 mm for GRE/GRP piping)
To eliminate exposure of elements to temperature extremes, outside their design
limit.
To limit undesirable line movements to protect sensitive equipment against
overloading.
To redirect pipe thermal movements to the favourable direction
To reduce excessive loading in support itself
To sustain Hydraulic thrust

The hydraulic thrust in the pipeline is

present at certain points such as pressure-
reducing valve, relief valve, bellows, etc.

If the control valve has a large pressure

differential and the line size is more, then
this force can be very high.
Piping support terminologies and definitions

Brace or Bracing Support- A device primarily intended to resist displacement of

piping due to forces other than thermal expansion and gravity.

Anchor Support or Fixed Support- A rigid restraint providing substantially full fixation
is termed as an anchor. Anchor support restricts all six degrees of freedom and does
not allow the pipe to move in any direction. Normally Full Welded or Bolted supports
are called anchor supports. Full Anchor supports are rarely used in piping systems.

Stop- A device that permits rotation but prevents translatory movements of piping. A
line stop or axial stop prevents pipe movement in the axial direction of the pipe. It is
also known as a stopper.

Guide- A device that prevents the rotation of one or more axis is called a guide (Fig.
10). Guide supports prevents Lateral pipe movements.

Hold Down Support- A device that holds the pipe in position disallowing vertical
upwards movement or allows decided upward movement. Hold down supports
prevent pipe dis-engagement from the Support structure.
Hanger- A support by which piping is suspended from a structure that functions by carrying
the piping load in tension.

Resilient support- A support that includes one or more largely elastic members to carry
pipe sustain + thermal loads at the same time allowing pipe thermal movement in the
desired direction.

Rest Support or Sliding support- A device that is provided below piping to take gravity
loads, offering no resistance other than frictional to horizontal motion. Rest supports do
not allow the pipe to sag or move downward.

Rigid support- A support providing stiffness in at least one direction.

Damping element- A device that increases damping of a system offering high resistance
against rapid displacement, caused by dynamic loading while permitting essentially free
movement.

Adjustable Support– An adjustable support (Fig. 9) can be adjusted at the site during plant
operation. These supports are normally provided for pipe and equipment alignment
purposes.

Dummy Leg – Basically an extension pipe welded to an elbow, to provide support either as
a resting, anchor, etc.
Types of Piping Supports

The following types of piping supports are most popular in the oil and gas,
petrochemical industry.

Hanger Supports – 1) Variable Hanger 2) Constant Hanger 3) Rigid Hanger.

Dynamically Loaded Supports – 1) Struts 2) Snubbers 3) Sway Brace 4) Energy

absorbers 5) Pipe Clamps 6) Pipe whip / Hold down restraints.

Pipe Bearing Components – 1) Pipe Saddle 2) Pipe Shoe 3) Pipe Trunnion 4) Wear
Pad.

Threaded Members – 1) welding nut 2) welded beam attachment 3) Clevis 4)

Turnbuckle 5) Tie rod 6) Stud bolt, nut, locknut, spring washers, etc.

Slide Bearing Plates – Teflon, Stainless steel, graphite.

Pipe Codes and standards

The American Petroleum Institute (API) Standards

API 5L – Specification for Line Pipe
API 6D – Pipe Line Valves, End Closures, Connectors and Swivels
API 6F – Recommended Practice for Fire Test for valves
API 593 – Ductile Iron Plug Valves – Flanged Ends
API 598 – Valve Inspection and Test
API 600 – Steel Gate Valves
API 601 – Metallic Gaskets for Refinery Piping
API 602 – Compact Design Carbon Steel Gate Valves
API 604 – Ductile Iron Gate Valves – Flanged Ends
API 605 – Large Diameter Carbon Steel Flanges
API 607 – Fire Test for Soft Seated Ball Valves
API 609 – Butterfly Valves
API 1104 – Standard for Welding Pipeline and Facilities
The American National Standards Institute (ANSI) Standards

ASME B31.1 – Power Piping

ASME B31.2 – Fuel Gas Piping
ASME B31.3 – Process Piping
ASME B31.4 – Pipeline Transportation Systems for Liquid Hydrocarbons and Other
Liquids
ASME B31.5 – Refrigeration Piping and Heat Transfer Components
ASME B31.8 – Gas Transmission and Distribution Piping Systems
ASME B31.8S- Managing System Integrity of Gas Pipelines
ASME B31.9 – Building Services Piping
ASME B31.11 – Slurry Transportation Piping Systems
Advantages of Working with Code and Standards

They establish a commonality in engineering criteria, terms, principles,

practices, materials, processes, etc.
They help user establish a standard way of working.
They ensure built in safety, reliability and continuity.
They minimize mismatches and promote interchangeability.
They economize the system, reduce inventory and ensure readily available
backup from market.
They help in accumulation of knowledge.
They help in avoiding reinventing the wheel again.
Indian Standards
Bureau of Indian Standards (BIS) have so far not developed an Indian Standard for the
design of Piping Systems
ANSI Standards ASME 31.1 and 31.3 are widely used for the design. These standards
also accept materials covered in other standards. Unlike American Standards, Indian
Standards cover dimensions and material specifications under the same standard
number.
IS 210 : Grey Iron Castings
IS 226 : Structural Steel (superseded by IS 2062)
IS 554 : Dimensions of Pipe Threads
IS 778 : Specification for Copper Alloy Gate, Globe and Check Valves
IS 780 : Specification for Sluice Valves – 50 NB to 300 NB
IS 1239 (Part I and II) : Specification for Mild Steel tubes and fittings
IS 1363 : Hexagonal Bolts, Screws and nuts – Grade C
IS 1364 : Hexagonal Bolts, Screws and nuts – Grade A and B
IS 1367 : Technical supply conditions for threaded steel fastners
IS 1536 : Centrifugally Cast Iron Pipes
IS 1537 : Vertically Cast Iron Pipes
IS 1538 : Cast Iron Fittings
IS 1870 : Comparison of Indian and Overseas Standards
IS 1879 : Malleable Iron Pipe Fittings
IS 1978 : Line Pipe, IS 1979 : High Test Line Pipe
IS 2002 : Steel Plates
IS 2016 : Plain Washers
IS 2041 : Steel Plates for Pressure Vessels used at moderate and low temperature
IS 2062 : Steel for general structural purposes
IS 2379 : Color Code for Identification of Pipelines
IS 2712 : Compressed Asbestos Fiber Jointing
IS 2825 : Code for Unfired Pressure Vessels
IS 2906 : Specification for Sluice Valves – 350 NB to 1200 NB
IS 3076 : Specification for LDPE Pipes
IS 3114 : Code of Practice for laying pipes
IS 3516 : Cast Iron flanges and flanged fittings for Petroleum Industry
IS 3589 : Seamless or ERW Pipes (150 NB to 2000 NB)
IS 4038 : Specifications for Foot Valves
IS 4179 : Sizes for pressure vessels and leading dimensions
IS 4853 : Radiographic Examination of Butt Weld Joints in pipes
IS 4864 to IS 4870 : Shell Flanges for vessels and equipments
IS 4984 : Specification for HDPE Pipes
IS 4985 : Specification for PVC Pipes
IS 5312 : Specification for Check Valves
IS 5572 : Classification of Hazardous area for Electrical Installation
IS 5822 : Code of practice for laying welded steel pipes
IS 6157 : Inspection and Testing of Valve
IS 6286 : Seamless and Welded pipes for Subzero temperatures
IS 6392 : Steel Pipe Flanges
IS 6630 : Seamless alloy steel pipes for high temperature service
IS 6913 : Stainless Steel tubes for food and beverage industry
IS 7181 : Horizontally cast iron pipes
IS 7240 : Code of Practice for Cold Insulation
IS 7413 : Code of Practice for Hot Insulation
IS 7719 : Metallic spiral wound gaskets
IS 7806 : Stainless Steel Castings
IS 7899 : Alloy Steel castings for pressure services
IS 8008 : Specification for molded HDPE Fittings
IS 8360 : Specification for fabricated HDPE Fittings
IS 9890 : Ball Valves for general purposesIS 10221 : Code of Practice for coating and
wrapping of underground MS pipelines
IS 10592 : Eye wash and safety showers
IS 10605 : Steel Globe Valves for Petroleum Industries
IS 10611 : Steel Gate Valves for Petroleum Industries
IS 10711 : Size of Drawing Sheets
IS 10805 : Foot Valves
IS 10989 : Cast / Forged Steel Check Valves for Petroleum Industry
IS 10990 : Technical drawings – Simplified representation of pipelines
IS 11790 : Code of Practice for preparation of Butt welding ends for valves, flanges
and fittings
IS 11791 : Diaphragm Valves for general purposes
IS 11792 : Steel Ball Valves for Petroleum Industry
IS 12709 : Specifications for GRP pipes
IS 13049 : Specifications for Diaphragm type float operated valves
IS 13095 : Butterfly Valves
IS 13257 : Ring type joint gasket and grooves for flanges
 MECHANICAL DESIGN OF PIPING SYSTEMS

Wall thickness: pipe schedule

The pipe wall thickness is selected to resist the internal pressure, with an allowance for
corrosion. Processes pipes can normally be considered as thin cylinders; only high
pressure pipes, such as high-pressure steam lines, are likely to be classified as thick
cylinders and must be given special consideration.
Pipe sizes

Pipe sizes are based on the approximate diameter and are reported as nominal pipe
sizes. Although the wall thickness varies depending on the schedule number, the
outside diameter of any pipe having a given nominal size is constant and independent
of the schedule number. This permits the use of standard fittings and threading tools
on pipes of different schedule numbers.
8 11 21
3,14,18,21,29,35,46,47,49 ,59,65,66,69,70,71,79,85,92,,96
 PUMPING OF FLUIDS

Pumps are used to transfer fluids from one location to another.

The pump accomplishes this transfer by increasing the pressure of the fluid and, thereby,
supplying the driving force necessary for flow.

Power must be delivered to the pump from an external source.

Selection of Pumps

Selection of a pump for a specific service requires knowledge of the

Liquid to be handled,
Total dynamic head required,
Suction and discharge heads,
liquid corrosion characteristics

And, the temperature, viscosity, vapor pressure, and density of the fluid.

Special attention will need to be given to those cases where solids are contained in
the liquid
The different types of pumps commonly employed in industrial operations can be
classified as

(1) Centrifugal pumps (including turbine and axial pumps)

(2) Positive displacement pumps
(3) Jet pumps,
(4) Electromagnetic pumps.

Centrifugal Pumps

This pump is the type most widely used in the chemical industr for transferring all
kinds of liquids. Such pumps range in capacity from 0.5 to 2 x 104 m3/h and can
provide discharge heads from a few meters to approximately 4.9 x 103 m (equivalent
to a pressure of 48 MPa).
9 11 2021

Absent no. 2,5,14,15,20,31,35,37,43,47 52,66,71,75,79,85,88,92,93,104

https://unacademy.com/lesson/chemical-
technology-previous-year-questions-11-
20/3OHFV8Q7

https://unacademy.com/lesson/chemical-
technology-previous-year-questions-91-
100/N9LFNI22
12 11 2021

Absent no. 2,13,14,35,37,42 66,67,71,76,93,95,96,103

16 11 2021
Ab.
53,55,60,64,68,70,75,78,81,85,89,101,102,103
,104,106