BANSILAL RAMNATH AGARWAL CHARITABLE TRUST’S

VISHWAKARMA INSTITUTE OF TECHNOLOGY

PUNE- 411037
(An Autonomous institute Affiliated to University of Pune)

Project Report
On

Design Of Heat Exchanger for Manufacturing

of Hydrochloric Acid

Under The Guidance of

Prof. Dr. Hemlata Uday Karne

Presented By: CH-B2- Group 9

12020121 30 Patil Rushikesh

11910969 33 Parth Patle
12020195 36 Puri Ashutosh
12020172 42 Rankhamb Shubham
12020015 48 Sanap Rajkumar
 Contents

1. Introduction

2. Literature Survey

3. Manufacturing process

4. Design

5. Conclusion

6. References
 Introduction
Hydrogen chloride (HCl), a compound of the elements hydrogen and chlorine,
a gas at room temperature and pressure. A solution of the gas in water is
called hydrochloric acid. Hydrogen chloride may be formed by the direct
combination of chlorine (Cl2) gas and hydrogen (H2) gas; the reaction is rapid at
temperatures above 250 °C (482 °F). The reaction, represented by the equation
H2 + Cl2 → 2HCl, is accompanied by evolution of heat and appears to be
accelerated by moisture. Hydrogen chloride is commonly prepared both on a
laboratory and on an industrial scale by the reaction of a chloride, generally that
of sodium (NaCl), with sulfuric acid (H2SO4). It is also produced by the reaction
of some chlorides (e.g., phosphorus trichloride, PCl 3, or thionyl chloride,
SOCl2) with water and as a by-product of the chlorination of many organic
substances (e.g., methane or benzene).

Hydrochloric acid is prepared by dissolving gaseous hydrogen chloride in

water. Because of the corrosive nature of the acid, ceramic, glass, or sometimes
tantalum apparatus is commonly used. Hydrochloric acid is usually marketed as
a solution containing 28–35 percent by weight hydrogen chloride, commonly
known as concentrated hydrochloric acid. Anhydrous liquid hydrogen chloride
is available, but because heavy and expensive containers are required to store it,
the use of hydrogen chloride in this form is limited.

Hydrochloric acid is present in the digestive juices of the human stomach.

Excessive secretion of the acid causes gastric ulcers, while a marked deficiency
of it impairs the digestive process and is sometimes the primary cause of
deficiency anemias. Exposure to 0.1 percent by volume hydrogen chloride gas
in the atmosphere may cause death in a few minutes. Concentrated hydrochloric
acid causes burns and inflammation of the skin.

Hydrochloric acid (HCl) is a versatile chemical that has a number of different

industrial uses. Some examples are hydrometallurgical processing (e.g.,
production of alumina and/or titanium dioxide), chlorine dioxide synthesis,
hydrogen production, activation of petroleum wells, and miscellaneous
cleaning/etching operations including metal cleaning (e.g., steel pickling). Also
known as muriatic acid, HCl is used by masons to clean finished brick work.
Hydrochloric acid is also a common ingredient in many reactions and is the
preferred acid for catalyzing organic processes. One example is a carbohydrate
reaction promoted by hydrochloric acid, analogous to those in the digestive
tracts of mammals. Hydrochloric acid may be manufactured by several different
processes; however, over 90 % of the HCl produced in the U.S. is a by-product
of the chlorination reaction. Some examples of chlorination reactions are the
production of dichloromethane, trichloroethylene, perchloroethylene, and vinyl
chloride.

Chlorine and hydrochloric acid works are taken together because chlorine is
often generated as an intermediate in the manufacture of hydrochloric acid. The
classis mercury cell electrolysis produces both chlorine and hydrogen and these
are then mixed and burnt to form hydrochloric acid gas, hydrochloric acid gas
can also be formed from the use of chlorides in chemical processes, especially
when a chloride and an acid react together. In all cases, the hydrochloric acid
gas is absorbed in water to form liquid hydrochloric with an acid strength of 33-
35 percent. Air pollution problems can also arise when chlorine or hydrochloric
acid are used in other processes. Chlorine works are defined as works in which
chlorine is made or used in any manufacturing processes. Hydrochloric acid
works are defined as works where hydrogen chloride gas is evolved either
during the preparation of liquid hydrochloric or for use in any manufacturing
process, or as the result of the use of chlorides in a chemical process.
 Literature Survey

Transfer of heat from one fluid to another is an important operation for most of
chemical industry. To achieve a particular engineering objective, it is very
important to apply certain principles so that the product development is done
economically. This economic is important for the design and selection of good
heat transfer equipment. Such equipment’s for efficient transfer of heat are
called as heat exchangers. Thus heat exchangers facilitate the exchange of heat
between the fluids that are different temperature while keeping them from
mixing with each other. Heat exchangers find widespread use in power
generation, chemical processing, electronics cooling, air-conditioning,
refrigeration, and automotive applications. These heat exchangers had become
the essential requirement of the current society as they do not cause any harmful
effects to the environments. The cost involved in this energy extraction is also
very less and economical. There are different types of heat exchangers with
different designs, materials and have been customized to meet specific needs.
Out of this Shell and Tube heat exchanger without doubt, one of the most
widely used heat exchanger. Shell and tube heat exchangers are commonly used
in the chemical and process industries. These devices are available in a wide
range of configurations as defined by the Tubular Exchanger Manufacturers
Association (TEMA). The applications of single-phase shell-and-tube heat
exchangers are quite large because these are widely in chemical, petroleum,
power generation and process industries. In essence, a shell and tube exchanger
is a pressure vessel with many tubes inside of it. One process fluids flows
through the tubes of the exchanger while the other flows outside of the tubes
within the shell.

I. Classification: -
This TEMA-type designation comprises three capital letters. The letter
describes the stationary head type at the front end of the apparatus, according to
the first column of Fig 1: five different alternatives are possible. The second
letter describes the heat exchanger shell, selected from the seven types shown in
the middle column of Fig. 1. Finally, the third letter, chosen from the eight
alternatives shown in the third column of Fig. 1, describes the stationary or
floating head type at the rear end. For example, an AES TEMA-type S&THX is
an exchanger with a channel and removable cover front head, a one-pass shell,
and a floating head with backing device rear end. The three most common types
of shell-and tube exchangers are Fixed tube-sheet design (L, M, and N type rear
header) This is a very popular version as the heads can be removed to clean the
inside tubes.

Fig. 1 Shell & Tube Heat Exchanger

The front head piping must be unbolted to allow the removal of front head, if
this is undesired this can be avoided by applying a type a front head. It is not
possible to clean the outside surface of the tubes as these are inside the fixed
part. Chemical cleaning can be used. B. U-tube design (front header and M type
rear header) It permits unlimited thermal expansion the tube bundle can be
removed for cleaning and small bundle to shell clearance can be achieved C.
Floating-head type (P, S, T, W type rear headers). A floating head is excellent
for applications where the difference in temperature between the hot and cold
fluid causes unacceptable stresses in the axial direction of the shell and tubes.
The floating head can move.
Manufacturing Process:

Hydrochloric acid is manufactured by following methods:

1) From various chlorination reaction: C6H6 +Cl2 → H6H5Cl + HCl

2) From salt and sulphuric acid: 2 NaCl + H2SO4 → 2 HCl + Na2SO4
3) From Synthesis process: H2 + Cl2 → 2 HCl

From Salt and Sulphuric Acid:

Fig. 1 Manufacturing of HCl from Salt & Sulphuric Acid

Process Description:

Reactions: NaCl + H2SO4 → NaHSO4 + HCl

NaHSO4 + NaCl → Na2SO4 + HCl

 Both reactions involve the displacement of volatile acid from salt. The
equilibrium can be displaced in desired direction by choice of condition i.e.
promoting volatilization of HCI.
 The high temperature process is superior to vacuum for this purpose. To
promote reaction rate, it is desirable to have temperature sufficiently high to
keep at least one of the reacting component in liquid condition.
 There is no difficulty in first stage of decomposition but second stage
required temperature of about 400°C to liquefy NaHSO 4. The higher limit to
temperature is the attack of corrosive relative mass on furnace. The sludge
i.e. Na₂SO4 is collected from bottom of the furnace.
 The product and unconverted H₂SO4 is send to further processing in which
there is recovery of H₂SO4 by cooling tower and HCI is recovered as main
product from absorber.

Synthesis Process:

 The process generates hydrogen chloride by burning chlorine in a few per

cent excess of hydrogen, chlorine and hydrogen are obtained as by-products
during the manufacture of caustic soda (electrolysis of NaCl solution).
 Process Description:
 Dry hydrogen is made to bum in acid-resisting burner fitted in a combustion
chamber lined with silica bricks. Dry chlorine is passed into the combustion
chamber when hydrogen burns in an atmosphere of chlorine to give to give
HCl.
 The gas is passed through a Cooler cooled by water spray and then through
Absorber through which water flows down in controlled quantities.
 The absorber is also cooled by a spray of cold water to remove the heat of
absorption of HCI in water. The solution of HCI flows into Storage tank
below.
 An exhaust fan on the extreme right pumps out the waste gases which escape
in the atmosphere.
 Design :-

 Calculation

Shell Side
Temperature   Tube Side Temperature  

Temperature   Unit Temperature   Unit

       
28
T1 0 °C t1 25 °C
19
T2 5 °C t2 75 °C

Uni
Pressure   Unit Pressure t
       
P2 4.3 Bar P1 2.3 Bar

Mass flow rate of sulphuric acid + Salt = 100000 kg/hr 27.77777778 kg/sec
37665.3
Mass flow rate of steam =   4 kg/hr 10.46259553 kg/sec

DT1= T1 - t2 205 °C

DT2= T2 - t1 170 °C
Assum
e
Outer diameter
= 20 mm 0.02 m
Inner diameter= 16 mm 0.016 m
Length
= 4.88 m  
Radius
=   0.01 m    

Cp for sulphuric acid = 1.34 KJ/Kg.°C

Cp for H20 = 4.2 KJ/Kg.°C

Q = M* CP *
DT  
Q= 3163.889 W

Coolong Water flow

= Q/Cp * DT
   
Kg/H
  37665.34 r

DTlm= (DT1-DT2)/LN(DT1/DT2)
   
DTlm= 186.9543 °C  

Q = U*A*Tlm*Ft  
A= Q /( U*(Tlm*Ft))  
   
A= 914.1403588 m2

Assuming,

W/K
U= 550 m^2
Ft = 0.85  
R= 1.7
S= 0.588235294

Tubes

Outer diameter = 20mm 0.02 m

Inner diameter=16mm 0.016 m
Tube length =   4.88 m

Actual Available Length

= 4.83 m
         

0.05 m would be in the tube

sheet

3013.74
No. of tubes = 2 3014

Tringular pitch

Pt= 1.25 pitch

Tube bundal
dia Db = Dod (NT/K1)^(1/n1)

K1 = 0.249
n1 = 2.207

Db = 1.415883 m 1415 mm

Shell
Additional Clearance = 68 mm  
     
148
Total Dia. of Shell = 3 mm  
Simulation in DWSIM
Heat exchanger 1-

Fig. 3 Feed Inlet (First Heat Exchanger)

Fig. 4 Hot Water Inlet

Fig. 5 Hot Water Outlet

Fig. 6 Feed Outlet

Fig. 7 Heat Exchanger Specification
 Fig. 8 First Heat Exchanger

Table No. 1

Fig. 9 Second Heat Exchanger

Table No. 2

Fig. 10 Third Heat Exchanger

Table No. 3

Conclusion

In the manufacturing process, heat exchangers are used to recover heat from
two process fluids. Shell-and tube heat exchangers are the most commonly used
heat exchangers in process industries due to their comparatively quick
production and adaptability to diverse operating conditions. Nowadays,
however, a variety of companies are looking for more competitive and less time
Consuming alternatives for building heat exchangers for shells and tubing.
According to literature and industrial studies, there is a need for successful
design solutions for manufacturing HCL. The construction of exchanger
requires a vast number of geometric and operational variables as part of the
quest for an exchanger geometry that satisfies the necessity for heat duty and a
series of design constraints. Typically the reference geometric configuration of
the equipment is selected first and the permissible pressure drop value is set.
The values of the design variables are then specified on the basis of the design
requirements and the assumption of certain mechanical and thermodynamic
parameters in order to provide a satisfactory coefficient of heat transfer leading
to an acceptable use of the heat exchanger surface.

The construction of heat exchanger, i.e. thermal and mechanical design, was
carried out by means of DWSIM specifications, both manually and using
software. It is noticed that the construction of exchanger accomplished by both
methods is very straightforward, basic advancement and time-consuming as a
modern heat exchanger.

References

1. Dryden's Outlines Of Chemical Technology by Rao

2. Nptel, “Lecture 1: Heat Exchangers Classifications,” Chem. Eng. Des. - II,
2006.
3. I. Horvath, “HEAT EXCHANGER DESIGN.,” Glas. Int., 1983, doi:
10.13182/nse66-a12015184.
4. K. Thulukkanam, Heat Exchanger Design Handbook. 2013.