STUDY OF LC’s AND MCC’s AND THEIR

DISTRIBUTIONS

RASHTRIYA ISPAT NIGAM LIMITED (RINL)

VISHAKAPATNAM STEEL PLANT

VISHAKAPATNAM, ANDHRA PRADESH

NATIONAL INSTITUTE OF TECHNOLOGY SILCHAR,ASSAM

DEPARTMENT OF ELECTRICAL ENGINEERING

A report submitted as a part of the Industrial Orientation INTERNSHIP in the TPP Department,
Visakhapatnam Steel Plant, By

REDDY APPARAO KOWSHIK – Trainee No. – 100043181

CHENGALA SWARUPA – Trainee No. – 100043484
PANDI SAI CHAITANYA – Trainee No-100043051

Under the Esteemed Guidance of MR. GUMMALA.GADWIN(DEPUTYMANAGER CWTP(E] TPP)

RASHTRIYA ISPAT NIGAM LIMITED (RINL), VISAKHAPATNAM

(Duration: 19th May 2025 to 28th June 2025)

1
 INDEX

S. No. Chapter Title Page No.

1 Certificate 4

2 Declaration 5

3 Acknowledgment 6

4 Preface 7

5 Abstract 8

6 Overview of RINL Steel Plant 9

7 Thermal Power Plant 18

8 Overview of demineralisation plant 20

9 Motor control centers (MCC’s) 23

10 Load Control Panels (LC’s) 25

Deaeration plant –MCC’S - SHEMERS

11 27
12 CWTP, MCC-1, DM-section L&T switch gear 29

2
 Components

13 35
14 Boilers 37

15 Steam turbine 41

S. No. Chapter Title Page No.

16 Chilled water plant 46

17 Water demineralization 48

18 Safety devices and automation 49

19 Conclusion 55

3
 CERTIFICATION

This is to certify that the internship program entitled STUDY OF POWER

SYSTEM CONFIGURATION IN TPP OF VSP has been carried out by the following
students in partial fulfilment of requirements for the award of Bachelor of Technology in
Electrical Engineering at NATIONAL INSTITUTE OF TECHNOLOGY SILCHAR,ASSAM
. This is a Bonafide work carried out by them in the Vizag Steel Plant (VSP) under my
guidance and supervision, from 19th-May-2025 to 28thJune-2025.

REDDY APPARAO KOWSHIK – Trainee No. – 100043181

CHENGALA SWARUPA – Trainee No. – 100043484
PANDI SAI CHAITANYA – Trainee No-100043051

GUMMALA.GADWIN

(DEPUTYMANAGER CWTP(E] TPP)

THERMAL POWER PLANT VIZAG

STEEL PLANT
DECLARATION

We hereby declare that the internship report titled “Study of Power System Configuration in
TPP of VSP” is a bonafide work carried out by us. This report has been prepared
independently, based on the knowledge acquired during our internship, and using data

4
available from the Vizag Steel Plant (VSP). We affirm that this work has not been submitted
to any other institute or organization for any academic or professional purpose.

5
 ACKNOWLEDGEMENT

We hereby take this opportunity to express our sincere gratitude to the following
eminent personalities whose support and guidance helped us complete this project successfully
without any difficulty.

We would like to express our deep gratitude to Mr. M.PRABHAKAR , DGM

Manager, TPP Department, Visakhapatnam Steel Plant, for his valuable guidance, constant
encouragement, and insightful support throughout the course of this project. His explanations
of fundamental concepts, industry requirements, and yard management systems have been
instrumental in enhancing our technical understanding. MR. GUMMALA.GADWIN
(DEPUTYMANAGER CWTP(E] TPP)

We are immensely thankful for his support and facilitation during our industrial training. His
role in enabling this learning opportunity is highly appreciated.
We also extend our sincere thanks to the Learning and Development Centre
(L&DC) for their structured safety training sessions and continuous encouragement, which
were crucial in the successful completion of our internship.
Finally, we thank all those who contributed directly or indirectly in successfully
carrying out this work, including the staff, engineers, and colleagues who provided help,
insights, and cooperation during the project.

Submitted By:
REDDY APPARAO KOWSHIK – Trainee No. – 100043181
CHENGALA SWARUPA – Trainee No. – 100043484
PANDI SAI CHAITANYA – Trainee No-100043051

6
 PREFACE

This study project report titled “Study of Power System Configuration in Thermal Power
Plant (TPP) of Visakhapatnam Steel Plant (VSP)” has been undertaken as part of the
academic requirements of the Bachelor of Technology in Mechanical Engineering. The
objective of this project is to gain a detailed understanding of the power system layout, key
components, and interconnections that enable efficient power generation and distribution
within a large-scale thermal power facility.

Thermal power continues to play a vital role in meeting India’s growing energy demands,
and acquiring first-hand exposure to the system architecture of such plants is crucial for an
aspiring mechanical engineer. As part of this study, I had the opportunity to visit and analyze
the operations at the Thermal Power Plant of Visakhapatnam Steel Plant, with particular
focus on the De-Mineralisation (DM) Plant—a critical component in maintaining water
quality and ensuring the long-term reliability of boiler and turbine operations.

This visit provided valuable insights into the integration of various subsystems such as high-
pressure boilers, turbines, power distribution units, control instrumentation, and water
treatment processes. The practical exposure helped bridge the gap between classroom theory
and real-world industrial practices, deepening my understanding of power system
configuration and operational efficiency.

This report is a structured presentation of the technical knowledge acquired, observations

made during the site visit, and relevant system analysis. I hope it proves to be a useful
resource for students, academicians, and professionals interested in thermal power plant
operations and power system design.

ABSTRACT

This project report presents a comprehensive study of the power system configuration in the
Thermal Power Plant (TPP) of Visakhapatnam Steel Plant (VSP), with a special focus on the
De-Mineralisation (DM) Plant. Thermal power continues to be a major contributor to India’s
electricity generation, and understanding the structure, control, and operation of its power
systems is essential for students of Electrical Engineering.
The study explores the generation, transmission, and distribution aspects of the power system
within the TPP. Key components such as alternators, excitation systems, step-up transformers,
switchgear, protection systems, and control panels have been analyzed in detail. The
interconnection of these systems and their role in ensuring reliable power supply within the
industrial complex are discussed .

7
A special emphasis is placed on the De-Mineralisation Plant, which plays a critical
supporting role by supplying high-purity water required for steam generation and condenser
operations. The electrical infrastructure involved in the DM plant—such as motor controls,
automation systems, relay coordination, and instrumentation—has been studied as part of this
project to understand how it integrates with the broader power system. An industrial visit to
the TPP at VSP provided valuable practical insights into equipment specifications, SCADA
systems, and the safety protocols implemented in a high-demand industrial environment.
Theoretical concepts such as the single-line diagram of the plant, load flow, fault analysis, and
protection coordination are used to support the practical observations

8
 OVERVIEW OF RINLSTEEL PLANT

Fig 1: RINL STEEL PLANT

Visakhapatnam Steel Plant (VSP) is the integrated steel plant of Rastriya Ispat Nigam
Limited (RINL), located in Visakhapatnam, Andhra Pradesh. Established in 1971, VSP stands as a symbol
of India's industrial prowess and commitment to self-reliance in the steel sector.
The plant strikes every visitor with a profound sense of awe, wonder, and admiration, as it showcases
excellence in all aspects—technology, management, product quality, human resources, and
environmental stewardship—all set against the scenic backdrop of the Bay of Bengal and Gangavaram
Beach. The tall and massive structures of the plant not only reflect cutting-edge technological architecture
but also the vision behind India’s industrial transformation.

Historical Background:
The decision to establish a steel plant in Visakhapatnam was officially announced in Parliament by then Prime
Minister Smt. Indira Gandhi on 17th January 1971. VSP became the first coastal-based integrated steel
plant in India, located 16 km west of the city of destiny, Visakhapatnam. Its geographical location facilitates
easy access to raw materials and efficient export logistics.

Installed Capacity and Product Range:

Originally commissioned with a capacity of 3 million tonnes per annum (MTPA) of liquid steel and 2.656
MTPA of saleable steel, VSP is equipped with modern and automated technologies to ensure seamless
production and product excellence. The plant focuses on total automation and system integration for
enhanced operational efficiency.
The product portfolio includes:
• Wire Rod Coils
• Rebars
• Rounds and Forged Rounds
• Angles, Channels, and Beams (Structural Steel)
• Special Steels catering to niche industries
 9
These products conform to stringent international standards such as JIS, DIN, BIS, and BS, making them
highly competitive in both domestic and global markets.

Quality, Environmental, and Safety Certifications:

VSP has the distinction of being the first integrated steel plant in India to be certified with the following
three international standards:
• ISO 9001 – Quality Management
• ISO 14001 – Environmental Management
• OHSAS 18001 – Occupational Health and Safety Management
These certifications cover all facets of the plant’s operations including production, maintenance, services,
training, marketing, and even its procurement systems across India (including 4 regional marketing
offices, 20 branch offices, and 22 stockyards).

Environmental Commitment and Green Initiatives:

VSP has invested over ₹460 crores in Pollution Control and Environmental Management Systems,
which include:
• Effluent Treatment Plants (ETPs)
• Electrostatic Precipitators (ESPs)
• Dust suppression systems
• Real-time emission monitoring
In addition, the steel plant has transformed a once barren landscape into a lush green township by planting
over 3 million trees. These green initiatives make the VSP steel township one of the most environmentally
friendly industrial zones in the country.

10
 1. INTRODUCTION

ABOUT VISAKHAPATNAM STEEL PLANT:

Visakhapatnam Steel plant, the first coast-based steel plant, is located 16km southwest of the
City of Destiny, i.e. Visakhapatnam. Bestowed with modern technologies, VSP has an installed capacity
of 3 million tons per annum of liquid steel and 2.656 million tonnes of saleable steel. At VSP, there is
emphasis on total automation, seamless integration and efficient upgradation, which results in wide range
of long and structural products to meet the stringent demands of discerning customers within India and
abroad. VSP products meet exalting International Quality Standards such as JIS, DIN, BIS, BS etc.

VSP has become the first Integrated Steel Plant in the country to be certified to all three international
standards for quality (ISO-9001:2000), for Environment Management (1SO-14001) and for Occupational
Health and Safety (OHSAS-18001).The certificate covers quality systems of all operational, maintenance,
service units besides Purchase systems, training and Marketing functions, spreading over 4 regional
marketing offices, 20 branch offices and 22 stock yards located all over the country.

VSP, by successfully installing and operating efficiently Rs.460 crores worth of Pollution Control and
Environment Control Equipments and converting the barren landscape by planting more than 3 million
plants has made the Steel Plant, Steel Township and surrounding areas into a heaven of lush greenery.
This has made Steel Township a greener, cleaner and cooler place. VSP exports Quality Pig Iron and
Steel products to Sri Lanka, Myanmar, Nepal, Middle East, USA and South east Asia (pig iron).RINLVSP
was awarded "Star Trading House" status during 1997-2000 Having established a fairly dependable export
market, VSP plans to make a continuous presence in the export market. Having a total manpower of about
16,613. VSP has envisaged a labour productivity of 265 Tonnes per man year of Liquid Steel, which is
the best in the country and comparable with international levels.

Some of the salient State-of-the-art technologies in VSP are:

➢ 100% slag granulation at the BF Cast House ➢ 7-meter Coke Oven batteries with coke dry

quenching.

➢ The biggest blast furnaces in the country.

➢ Bell-less top charging system in Blast Furnace

➢ Suppressed combustion-L.D gas recovery system

➢ 100% continuous casting of liquid steel

➢ " Tempcore and Stelmor " cooling process in LMMM and WRM respectively.
➢ Extensive waste heat recovery systems
MAJOR PRODUCTION FACILITIES

11
 VSP has the following major production facilities:

- 5 coke oven batteries of 67 ovens each and 41.7 cu met Volume

- 2 Sinter machines of 312 sq. met area

- 3 Blast furnaces of 3200 cu met useful volume

- SMS with 3 LD converters of 150-ton capacity and 6 no’s of 4 strand continuous bloom casters

- Light and medium merchant mill of 7,10,000 tons per year capacity

- Wire rod mill of 8,50,000 tons per year capacity

- Medium Merchant & Structural mill of 8,50,000 tons per year capacity
In expanding VSP, establishing Blast furnace 3 and SMS 2 for the improvement of production

MAJOR DEPARTMENTS AT RINL VSP

➢ Raw Material Handling Plant

➢ Coke oven and coal chemical plant
➢ Sinter plant
➢ Blast Furnace
➢ Steel Melt Shop
➢ Rolling mills
➢ Light and medium machine mills
➢ Wire Rod Mill
➢ Medium Merchant and Structural Mill
➢ Thermal power plant

12
 ▪ RAW MATERIAL HANDLING PLANT(RMHP):

VSP annually requires quality raw materials viz. Iron Ore fluxes (Lime stone, Dolomite);
coking and non-coking coals etc. to the tune of 12-13 million Tons for producing 3 million Tons of Liquid
Steel. To handle such a large volume of incoming raw materials received from different sources and to ensure
timely supply of consistent quality of feed materials to different VSP consumers, Raw Material Handling
Plant serves a vital function. This unit is provided with elaborate unloading, blending, stacking & reclaiming
facilities viz. Wagon Tipplers, Ground & Track Hoppers, Stockyards Crushing Plants, Vibrating Screens,
Single/ Twin Boom Stackers, Wheel on Boom and Blender Reclaimers. In VSP peripheral unloading has
been adopted for the first time in the country. The Raw Material Handling Plant (RMHP) Department
procures the different raw materials from various sources.

Fig 2: RAW MATERIAL HANDLING PLANT

▪ COKE OVEN AND COAL CHEMICAL PLANT (CO & CCP):

The main function of this department is to convert the coal in to coke, which is received
from RMHP Department. Coke is a hard porous mass obtained by functional distillation of coal in absence
of air at a temperature above 125oC for a period of 16-18 hours.

It is used as a fuel and reducing agent for reduction of iron ore in blast furnace. Besides coke production,
several coal chemicals are being extracted in coal chemical plants. The coal chemicals are tar, benzyl, and
ammonia-based products. The coal is not consumed directly because coke helps in reducing the pollution.

13
 Fig 3: COKE OVEN BATTERIES

▪ SINTER PLANT (SP):

Sinter is a hard and porous lump obtained by agglomeration of Iron Ore fines, Coke breeze,
Limestone and Metallurgical Waste.
This department by not wasting the powder and small pieces of iron ore coal manganese, dolomite and
limestone makes Sinter Cakes and put it for reuse.
This increases the productivity of Blast Furnace, improves the quality of pig iron and decreases the

consumption of coke rate

Fig 4: SINTER PLANT

14
 ▪ BLAST FURNACE (BF):
Pig iron/hot metal is produced in the blast furnace. The furnace is named as blast furnace as
it runs with blast at high pressure with a temperature of 1150°C.Raw materials required for iron making are
iron ore, sinter, coke, and limestone. For one ton of hot metal production, 310 kg. iron ore, 1390 Kgs. sinter,
and 627 Kgs. of coke with some other additives.

VSP has two 3200 Cu. Meter BFs equipped with Paul Worth bell less top equipment with conveyor charging.
Rightly named as “Godavari” &” Krishna” after the two rivers of AP, the furnaces will help VSP in bringing
prosperity to the state of Andhra Pradesh. The two furnaces with their novel circular cast house and four tap
holes each can produce 9,720 tons of Hot metal daily or 3.4 million tons of low Sulphur Hot metal annually.

Fig 5: Blast Furnace

▪ STEEL MELT SHOP (SMS):

Steel is an alloy of Iron with carbon up to 1.8%. Hot metal produced in Blast Furnace contains
impurities like carbon, Sulphur, phosphorus, silicon, etc.; these impurities will be removed in steel making
by oxidation process. There are three LD converters to convert hot metal in to steel. 99.5 % Pure Oxygen
at 15-16 Kg/cm2.Pressure is blown in the converter trough Oxygen lance having Convergent and Divergent
copper nozzles at the blowing end Oxygen oxides the impurities present in the Hot Metal, which are formed
as slag with basic fluxes such lime. Different grades of steel of superior quality can be made by this or
process by controlling the oxygen blow or addition of various Ferro alloys special additives such as FeSi,
FeMn, SiMn etc.

15
 Fig 6: Steel Melt Shop

▪ ROLLING MILLS (RM):

Blooms cannot be used as they are in daily life. These blooms have to reduce in size and
properly shaped to fit for various jobs. Rolling is one of the mechanical processes to reduce larger size
sections in to smaller cones. The cast blooms are heated and rolled in to various long products of different
specifications at three high-capacity sophisticated high-speed rolling mills.

Fig 7: Rolling Mills

16
 ▪ LIGHT AND MEDIUM MERCHANT MILLS (LMMM):

LMMM comprises two units, namely Billet Mill and Bar Mill. The Billet Mill is facilitated
with 2 Walking Beam Furnaces and it is a continuous seven stand mill. In the Billet Mill 250 x 320 mm size
blooms are rolled into Billets of 125 x 125 mm size. Billets are supplied from this mill to Bar Mill of
LMMM, Wire Rod Mill and for sale.

Bar Mill is facilitated with tempcore heat treatment technology, automated bundling facilities and high
degree of automation. Bar Mill is a 2-strand continuous mill having a capacity of 7,10,000 tons per annum
and produces rounds and rebars of various sizes from 16 mm to 36 mm.

Fig 8: LMM Mills

17
 THERMAL POWER PLANT

Fig 9: Thermal power plant

The Thermal Power Plant (TPP) at Visakhapatnam Steel Plant (VSP) is an integral part of the facility’s
infrastructure, designed to ensure a reliable and continuous supply of power and process steam essential
for various steel production units. Thermal power generation is critical in a steel plant due to the high energy
requirements of processes like coke making, iron production, steel refining, and rolling operations. 1.
Purpose of the Thermal Power Plant
The TPP serves to:
• Generate electric power and high-pressure steam required for industrial processes within the steel
plant.
• Enhance energy efficiency by converting thermal energy from fuel combustion into usable electrical
and thermal energy.

• Maintain plant self-sufficiency in energy without depending on external grids. 2. Fuel Used in the

TPP
The TPP primarily uses thermal fuels such as:
• Pulverized coal
• Fuel oil
• Occasionally, a mix of industrial waste gases, when processed and treated properly
These fuels are burned in high-efficiency water-tube boilers to produce high-pressure stea

18
3. Boiler Systems
The TPP at VSP features modern, high-pressure boilers equipped with:
• Water walls and superheaters to ensure dry and high-temperature steam
• Economizers and air preheaters to improve thermal efficiency by recovering waste heat
• Automatic control systems for safe and optimized operation
The boilers follow the Rankine cycle principle, converting heat energy into mechanical and electrical energy
via steam.

4. Turbine Systems
High-pressure steam from the boilers is directed to steam turbines, where it expands and rotates the turbine
blades, converting thermal energy into mechanical energy. The turbine shaft is coupled with a generator, which
produces electricity.
The turbine system includes:
• Impulse and reaction blade stages
• Governing systems for speed and load control
• Lubrication and cooling systems

5. Condensation and Water Recycling

After energy extraction, the low-pressure steam is condensed using surface condensers. The condensed water
(condensate) is then treated, reheated, and pumped back to the boiler in a closed-loop system. This reduces
water consumption and increases system efficiency.

6. Water Treatment System

To protect boiler and turbine equipment, the TPP has a dedicated water treatment section that includes:
• Demineralization (DM) plants
• Deaerators to remove dissolved gases
• Chemical dosing systems to control pH, corrosion, and scaling

7. Control and Safety Systems

The TPP is operated using a Distributed Control System (DCS) and automation for:
• Monitoring boiler temperature, pressure, and flow
• Controlling turbine speed, load, and output
• Managing alarms, interlocks, and emergency shutdowns
The plant also has ID (Induced Draft) and FD (Forced Draft) fans, chimneys, and pollution control
devices such as electrostatic precipitators (ESPs) to comply with environmental standards.

19
 OVERVIEW OF DEMINERALIZATION PLANT

Fig 10: Demineralization Plant

A De-Mineralisation (DM) Plant is a specialized water treatment facility used in thermal power plants and
industrial processes to produce high-purity water by removing dissolved salts and minerals. In power plants,
especially those operating on steam cycles, demineralized water is essential for protecting high-temperature
equipment such as turbines, condensers, and heat exchangers from scaling, corrosion, and other waterrelated
damage. The reliability, efficiency, and lifespan of thermal power systems heavily depend on the quality of
feedwater, making DM Plants a critical component of plant infrastructure.

Raw water used in power generation typically contains impurities like calcium, magnesium, sodium,
chlorides, sulfates, and silica, which can lead to scaling and deposits in boilers and turbines. The DM process
removes these impurities through stages such as pre-filtration, cation and anion exchange, mixed-bed
polishing, and regeneration. Each stage uses specialized ion-exchange resins to replace undesirable ions with
hydrogen and hydroxide ions, effectively producing ultrapure water. The process is closely monitored and
controlled using conductivity, pH, and silica analyzers to ensure strict quality standards are met.

In large-scale industrial facilities like the Visakhapatnam Steel Plant (VSP), operated by Rashtriya Ispat
Nigam Limited (RINL), the DM Plant plays a vital supporting role in sustaining uninterrupted power
generation and steam supply.

20
The DM Plant at VSP is equipped with advanced treatment units including pressure sand filters, activated
carbon filters, strong acid cation exchangers, degassers, strong base anion exchangers, and mixed-bed
polishers. Chemical dosing systems are also integrated to control pH levels and remove dissolved oxygen
through deaeration. The entire process is automated and monitored using Distributed Control Systems (DCS)
and SCADA, enabling real-time tracking of flow rates, regeneration cycles, water conductivity, and plant
efficiency.

In addition to maintaining process reliability, the DM Plant contributes to the plant’s environmental and
safety goals. Efficient water reuse and chemical handling systems minimize wastewater discharge, while
automatic regeneration reduces manual intervention and exposure to chemicals. The operation of the DM
Plant is aligned with environmental standards and is supported by safety protocols for chemical storage,
handling, and emergency response.

By ensuring the availability of high-quality demineralized water, the DM Plant at VSP supports the
continuous and efficient operation of critical power systems. It minimizes downtime, reduces maintenance
costs, and plays a key role in sustaining energy-intensive steel production processes. The plant exemplifies
the integration of precision engineering, automation, and sustainable water management in modern industrial
infrastructure.

Moreover, the DM Plant at VSP is not only essential for operational efficiency but also plays a strategic role
in energy conservation and sustainability. By maintaining the purity of feedwater, the plant minimizes the
frequency of blowdowns in boilers, thereby reducing water wastage and heat loss. This leads to improved
thermal efficiency across the power generation cycle. Additionally, the integration of automated controls and
real-time monitoring ensures optimal chemical usage, reduced regeneration frequency, and lower
environmental impact. In a high-demand industrial setting like VSP, where power and steam requirements
are substantial and continuous, the DM Plant acts as a silent but indispensable pillar that safeguards the
integrity of the entire thermal power system.

DE-MINERALISATION (DM) PLANT

The De-Mineralisation (DM) Plant is a critical part of the utility infrastructure in a Thermal Power Plant
(TPP), ensuring the continuous supply of high-purity water for high-pressure boilers, steam turbines, and
other thermal systems. Impurities such as dissolved salts, minerals, and gases in raw water can lead to scale
formation, corrosion, and efficiency losses in thermal power cycles. To eliminate these issues, the DM plant
treats raw or clarified water through a series of chemical and physical processes that remove ionic
contaminants, producing demineralized water suitable for power generation systems.

DM Plant Process Flow:

The DM Plant typically consists of the following major treatment units:
1. Pre-Treatment:
o Pressure Sand Filter (PSF): Removes suspended solids and turbidity.
o Activated Carbon Filter (ACF): Removes organic matter, chlorine, and odors.
2. Ion Exchange Treatment:

21
 o Cation Exchange Unit: Exchanges positive ions (Ca²⁺, Mg²⁺, Na⁺) with H⁺ ions.
o Degasser Tower: Removes carbon dioxide (CO₂) from water after cation exchange. o Anion
Exchange Unit: Exchanges negative ions (Cl⁻, SO₄²⁻, NO₃⁻) with OH⁻ ions.
o Mixed Bed Polisher: Final polishing stage to achieve ultrapure water quality.
3. Chemical Dosing Units: o Antiscalant, pH control, and sodium bisulfite dosing as required.

Treated Water Quality Parameters:

Parameter Typical
Value
pH 6.8 – 7.2

Conductivity < 0.2 µS/cm

Silica (SiO₂) < 0.02 ppm

Total Dissolved Solids < 1 ppm

Sodium (Na⁺) < 0.01 ppm

DM Plant Features:
1. Automation: Operated through DCS/SCADA systems for real-time monitoring of flow rates,
conductivity, pH, and regeneration cycles.
2. Regeneration Process: Uses acid (HCl) and alkali (NaOH) for resin regeneration in cation and anion
units, respectively.
3. Safety Measures: Includes neutralization pits, backwash systems, and safety interlocks for chemical
handling.
4. Water Recovery Efficiency: Typically 95–98% depending on plant design.

DM Plant Importance in TPP:

• Prevents scale and corrosion in high-pressure boilers and turbines.
• Enhances thermal efficiency by maintaining water chemistry within safe operating limits.
• Reduces frequency of maintenance shutdowns and equipment degradation.
• Supports closed-loop water-steam cycle sustainability.
• Integral to achieving ISO 14001 environmental and operational standards.

22
 Motor Control Centers (MCCs)
Visakhapatnam Steel Plant (RINL) operates a captive thermal power plant that provides reliable power for
steel production. The plant includes a Demineralization (DM) Plant essential for purifying feedwater for
boilers. The deaeration unit within the DM plant plays a key role in removing dissolved oxygen and carbon
dioxide, which can cause severe corrosion. Motor Control Centers (MCCs) in this context are responsible for
operating and monitoring all motor-driven equipment within the deaeration plant.

Fig 11: MCC Room in VSP

Overview of the Deaeration Plant

The deaerator functions by heating feedwater and removing dissolved gases through mechanical and thermal
processes. Typically, it consists of a spray section, tray section, venting system, and a storage tank. It operates
under controlled temperature and pressure conditions to achieve low levels of dissolved oxygen. This ensures
long-term boiler health and improved efficiency. Sensors, valves, and pumps form the key controlled devices
within the system. Introduction to MCCs
Motor Control Centers are integral switchgear assemblies used for controlling electric motors. In the DM
plant’s deaeration unit, MCCs start and stop motors, monitor running conditions, and provide protection.
MCCs in Vizag Steel typically handle 415V, 3-phase AC loads and provide both local and remote operational
flexibility. These panels consist of feeders equipped with contactors, relays, breakers, and timers. MCC
Components and Their Functions
MCCs are divided into compartments: incomer section, busbar chamber, and outgoing feeders. The incomer
receives power through breakers; busbars distribute it to feeders. Each feeder powers a specific motor or
control device. Protective devices like thermal relays, MCBs, and earth fault relays ensure safe operation.
The panels also include status indicators, push buttons, and selector switches for user interaction.

Loads controlled by MCCs in Deaeration

The MCCs control a variety of loads: feedwater pumps, venting fans, chemical dosing pumps, and
motorized valves. Instrumentation like level sensors and pressure switches are also powered and monitored.
These loads are critical for plant operation, and any malfunction can disrupt the deaeration process. Control
is possible from both the MCC panels and the central SCADA system.

23
Power Supply and Distribution Strategy

MCCs are fed from the main substation or a Unit Auxiliary Transformer, stepping voltage down from
6.6/11kV to 415V. A dual-incomer setup ensures redundancy. Power cables are XLPE armored types; control
cables are shielded. Proper earthing and segregation ensure safe and interference-free distribution to all loads
within the plant.
Protection Schemes and Interlocks
The MCCs employ protection schemes like overload, short-circuit, and earth fault protection. Interlocks
prevent unsafe operations, such as starting a pump without valve confirmation. Automation via PLCs and
SCADA ensures alarms, status updates, and trip logging. These features improve reliability and operational
safety.
Maintenance, Inspection, and Safety Protocols
Regular inspections include torque testing, relay calibration, and insulation resistance checks.
Thermographic scanning identifies hot spots. Safety protocols include Lockout-Tagout (LOTO), PPE usage,
and signages. Panels are kept dry and clean to avoid failures. Staff are trained for emergency scenarios and
mock drills are conducted.
Conclusion and Suggestions
MCCs in the deaeration section are vital for safe and efficient operation. They control all critical motors and
provide operational safety through interlocks and protection. Upgrading to intelligent MCCs and
implementing predictive maintenance can further enhance reliability. Following proper maintenance
schedules and training ensures long-term plant performance.

Load Control Panels (LCs)

The Demineralization (DM) Plant at Vizag Steel Plant is a crucial unit in ensuring that feedwater used in
boilers is free from dissolved salts and minerals. Local Control Panels (LCs) play a vital role in on-field
operation and control of instrumentation and electrical devices such as valves, pumps, and transmitters. This
report focuses on the role, structure, function, and distribution of LCs in the DM plant, with a focus on
realtime control and plant automation.

Fig 12: LC Room in VSP

24
Overview of the DM Plant
The DM Plant includes multiple stages such as filtration, ion exchange, degasification, and deaeration. Each
stage requires precise monitoring and control of parameters like flow, pressure, conductivity, and pH. Local
Control Panels serve as the first point of interface for these operations by providing local status, control
switches, and signal conditioning hardware for field instruments.
Function of Local Control Panels
LCs serve as the interface between field instruments and central control. They provide signal isolation, status
indication, manual control switches, and relay logic. Each LC is designed for a specific group of equipment
(e.g., pump control panel, valve panel). These panels ensure redundancy and local troubleshooting ability
during SCADA failure.
Types of LCs Used in the DM Plant
Different types of LCs include Pump Starter Panels, Valve Control Panels, Instrumentation Panels, and
Junction Boxes. Panels are typically made from mild steel or stainless steel, and are equipped with terminal
blocks, contactors, control relays, selector switches, push buttons, and status lamps.

Typical Field Devices Controlled

Field devices controlled by LCs include motor-operated valves, pressure transmitters, conductivity analyzers,
dosing pumps, level switches, and local indicators. LCs collect analog and digital signals and forward them
to MCCs or DCS via signal converters or I/O cards.
Wiring, Signal, and Power Considerations
LCs use multi-core shielded cables for instrumentation signals and power cables for connected motors.
Separation of signal and power wiring is maintained to reduce electromagnetic interference. Each cable is
tagged, and proper grounding is done to ensure operator safety and signal integrity.
Control Logic and Interfacing
LCs contain hardwired logic or PLC-based controls for device interlocking. They interface with MCCs,
transmitters, and DCS panels via 4-20 mA signals, DI/DO signals, or RS-485 communication. Redundant
logic is often built for safety-critical functions.
Maintenance and Inspection of LCs
Regular inspection includes checking for terminal tightness, relay functionality, cable insulation, and signal
continuity. Preventive maintenance ensures no ingress of moisture or dust, and proper functioning of control
buttons and indicators. Documentation and labeling are also checked. Safety, Protection, and Compliance
LCs are installed in IP54/IP65 enclosures, with earthing provisions, fuses, MCBs, and surge protection.
Safety protocols include Lockout/Tagout, PPE use, and signage. LCs conform to standards such as IS/IEC
60204 and IEEE wiring codes.
Conclusion and Recommendations
Local Control Panels serve as the backbone of field-level control in the DM Plant. Their strategic
placement and design ensure reliable control and monitoring even during central system failures.
Recommendations include digitizing LCs with HMI displays, using smart relays, and standardizing
preventive maintenance to enhance reliability and integration with Industry 4.0 systems.
DEAERATION PLANT – MCC SIEMENS

25
1F1 – Empty
1F2 – P4 – Deareated DM water pump to rolling mills stand by – 45KW
1F3 – P1 – Deareated DM water pump to PP & BH – 90KW
2F1 – Empty
2F2 – P4 – 2 Deareated DM water pump to PP & BH – 45KW 2F3
– P1 – 2 Deareated DM water pump to PP & BH – 90KW
3F1 – Empty
3F2 – Spare , 63A
3F3 – P2 – 1 Deareated DM water pump to COBP & SMS – 45KW
3F4 – Deareated DM water pump to PP & BH – 90KW
4F1 – Incomer – 1 , 1250A
4F2 – Control & relay panel
5F1 – Bus coopler , 1250A 5F2
– Control panel
6F1 – Incomer – 2 , 1250A
6F2 – Control & relay panel
7F1 – Empty
7F2 – Spare , 63A
7F3 – P2 – 2 Deareated DM water pump to COBP & SMS – 45KW
7F4 – P1 – 3 Deareated DM water pump to PP & BH – 45KW
8F1 – Empty
8F2 – P2 – 3 Deareated DM water pump to PP & BH – 90KW
9F1 – Empty
9F2 – P4 – 1 Deareator DM water pump to rolling mills – 45KW
9F3 – P1 – 6 Deareated DM water pump to PP & BH – 90KW DEAREATION PLANT – MCC [Backside
panels] SIEMENS

1R1 – Empty
1R2 – P2 – 4 Deareated DM water pump , COBP – 45KW
IR3 – P3 – 3 Deareated DM water pump , BF – 30KW
2R1 – Empty
2R2 – P3 – 1 Deareated DM water pump , BF – 30KW

26
2R3 – Control suplly , 2KVA
2R4 – Instrumentation supply 2.5 KVA
3R1 – Bus duck
4R1 - Bus duck
4R2 - Bus duck
5R1 - Bus duck
5R2 - Bus duck
6R1 - Bus duck
6R2 - Bus duck
7R1 – Empty
7R2 – P4 – 4 Deareated DM water pump to rolling mills – 45KW
7R3 – Spare , 90KW
8R1 – Empty
8R2 – P3 – 2 Deareated DM water pump , BF – 30KW
8R3 – Control supply , 2KVA
8R4 – Instrumentation supply , 2.5 KVA
CWTP, MCC-1, DM-SECTION L&T SWITCH GEAR
MB – 2A – Filter Air Blower – 15KW
MB – 2B – Filter Air Blower – 15KW
MB – 4A – Nutrilization pit blower – 45KW
Effluent blower
Reserve – 415V
Instrumentation control panel , 240V , 1pi
M – 8A DM regeneration water pump – 15KW
M – 6B Degassed water pump – 45KW
M – 9A Acid tranfer pump – 1.5KW
Mag – 11 Acid Diluation tank
Mixed bed agitator – 0.75KW
Mag – 10A Acid diluation tank cation – 1.1KW
M – 6A Degassed water pump – 45KW
MB – 1a Degassed air blower – 5.5KW
MB – 1 Degassed air blower – 5.5KW

27
Mag – 12B Lime solution tank agitator – 2.2KW
Control suplly – 1MCC , 240V
Reverse
Auxillary equipment
I/C – 1 , Incomer – 1 , 1600A supply from panel no. 13 of section 1 of 57LC05
Bus coupler , 1600A
Auxillary equipment feeder
Incomer – 2 , 1600A supply from panel no. of section – 2 of LC05
Auxillary Equipment Feeder
MB – 1B Degasser air blower – 5.5 KW
MB – 1C Degasser air blower – 5.5 KW
Mag – 2B , lime solution tank agitator – 2.2 KW
MCC – Control supply – 2
Reserve
M – 9B Acid transfer pump – 1.5 KW
MB – 1 Degasser air blower – 5.5 KW
Mag – 10B Acid dilution tank cation – 2.2 KW
MB – 4B Nutrilization pit air blower – 45 KW
Reserve – 415V , 3 phase
Reserve – 240v , 1 phase
M – 8B , DM regeneration water pump – 15 KW
M – 6E , Degassed water pump – 45 KW
MB – 3A , Mixed bed air blower – 15 KW
MB – 3B , Mixed bed air blower – 15 KW M
– 6D , Degassed water pump – 45 KW

CWTP MCC-1, DM-SECTION [Backside panels] L&T

M – 7E , DM water pump – 55KW
M – 7D , DM water pump – 55KW
M – 10B , Alkaline transfer pump – 1.5KW
Reserve instrumentation control supply – 415V
Mag – 7 ¸ Alkaline measuring tank agitator – 0.75KW

28
M – 6 , Degassed water pump , future – 45KW
Mag – 12C , Lime solution pump agitator – 2.2KW
Reserve – 415V
11 – C , Effluent disposal pump KWH meter
M – 7C , DM water pump – 55KW
11 – D , Effluent disposal pump – 22KW
11 – C , Effluent disposal pump – 22KW
11 -B , Effluent disposal pump – 22KW
Mag-9, Alkaline solution tank agitator-2.2kw
11-A, Efficient disposal pump-22kw
Reserve-415v,3ohm
11-A Efficient disposal pump-kwh meter
M-7A, Dm water pump-55kw
M-10A, Alkaline transfer pump
Reserve , 415v, 3ohm
Mag-6, Alkaline measuring tank agitator- 0.75kw
M-6c, Degassed water pump-45kw
Reserve
M-7B, DM water pump-55kw

CWTP-MCCJ-DM Section (LPT SCOITCHGEAR]

0.75 KW MOTORS:
Mog-lla, Acid bilution, tank, Mixed Bed Agitator
Mog-7, alkaline measuring tomk Agitator Mag-
6, alkaline measuring tarik agitator.
1.1KW MOTORS
M-10A, Acid wiwtion tank Agitator cation'
1.5KW MOTORS:
M-9A, Acid Transfer pomp
M-9B, acid Transfer pump
M-10A, elkaline Transfer pomp
M-10B, Alkaline Transfer Pornp

29
2.2KW MOTORS
Mag-12B, Lime Sowtion tank Agitator
Mag-28, Lime solution cank Agitator
Mag-12C, Lime Solution pump Agitator
Mog-9, Alkaline solution tank Agitator
5.5 KW MOTORS:
MB-1A, Degassed air Blower
MB-1B, Degassed Air Blower
M8-1C, Degassed Air Blower
15KW MOTORS:
MB-2A, Filter Air Blower
MB-2B, Filter Air Blower
M-8A, DM Regeneration water pump
M-8B, DM Regeneration coater pump
MB-3A, Mixed Bed Air Blower
MB-3B, Mixed Bed Air Polower
22KW MOTORS:
11-A, Efficient Disposal pump
11-B, Efficient Disposal pump
11-C, Efficient Disposal pump 11-
D, Efficient Disposal pump
45KW MOTORS!
MB-4a, Nutrilisation fit Blower
MB-4B, Efficient Blower
M-6A, Degassed water pomp
M-6B, DEGassed water pomp
M-6C, Degassed water pump
M-6D, Degassed water pump
M-6E, Degassed water pump
CWTP MCC-II, COND. SOFTENING SECTION
M-14C
1. oil free conditioning Pump 9.3kw

30
2. Ag-1A, Alum Solution tank 2.2kw
3. Mag-2A, Acid Dilution tank Agitator - 1.5kw
4. M-4A, clarified water pump- 55kw
5. M-14B, Oil Free conditioning pump-9.3kw
6. M-1A, Alum Transfer pump 1.5kw
7.MP-2A, Alum Dosing pump 0.37k@
8 M-4B, clarified water pump 55kw
9. MP-4A, Sodium Sulphate pomp 0.37KW
10. AG-13A, Sodium sulphate tank Agitator-0.75K@
11. AG-3A, coog Aid Solution tank Agitator-0.75kw
12. M-40, clarified water pump 55kw
13. MP-3A, coag Aid Solution Dosing pump-0.37kw
14. M-2A, chlorinated water Booster pump - 1.1KLD
15. clarifier sub OBI
16. Instrumentation control supply-2, 240V, 19
17. Το 24or control Supply Bus.
18. Spare
19. Auxillary GQuip ment
20. Incomer-1, from panel No: 2, Comp No:6 Section-I, of 57LC5 1000A
21. Bos coopler 1OOO A
22. Auxillary Equipment
23. Incomer-2, from panel No:11, Comp No. 16 Section-3, of 57LC5 1000 A 24. Auxillary Equipment
25. MP-3B, Coog Aid Solution Dosing Pump -0.37KW
26. M-2B, chlorinated water Booster pump -1.1KW
27. clarifier sob DB-2
28. Reserve- 240v, 1flux
29. To 240v, contrd supply Bus
30. Reserve. –
31 MP-4B, sodium sulphate pump-0.31kw
32. AG-13B, Sodium Sulphate tank agitator-0.75kw
33 AG-3B, coag And solutions task agitator - 0.75kw
34. M-4E, clarified water pump - 55KW

31
35. MP-1B, Acid boring pomp 0.37kw
36. M-1B, alum transfer pump 1.5kw
37. M-2B, alum Dosing pump 0.37kw
38. M-40, clarified water pump - 55kw
39. M-14A, all free conditioning pump- 9.3 kw
40. AG-IB, Alum Solution tank Agitator - 2.2kw
41. Mag-2B, Acid wilution tank agitator 1.5kw
42. M-4c, clarified water pump - 55kw
CWTP MCC-II COND & SOFTENING SECTION
1. M-13B, contaminated Cond.pomp 15k
2. De watering pump
3. Reserve, 415V, 30
4. M-5B, clarified coater pump-37kw
5. M-9B, Sludge Disposal pump-7-5KW.
6. A6-1B, Flash mixer Agitator - 3.7kw
7. M-16B, soft water pump
8. M-18B, Brine Transfer pump- 1.1kw
9. Acid Dilution tank -0.75KW
10. oil Skimmer 0.75KW
11.Spare
12. M-15C, condition pump-22kw
13. M-15D, condition pump-22 kw
14. M-15A, condition pump-22Kw
15. M-17B, Soft water pump. Sms-30kw
16. M-17C, Soft water Pump-future-30KW
17. M-17A, Soft water pump- Sms 30kw
18. M-15B, condition pump- 22kw
19. M-15A, condition pump 22 κω
20. M-16A, Soft coater pump - S.SKCO
21. AG-4A, Flash mixer Agitator - 3.7KW
22. M-3A, Sludge Disposal pump-7.5kW
23. M-18A, Brine Transfer pump-1.1kW

32
24. Mag-8, Alkaline, measuring kank 0.75Kw
25. MP-10, Acid Dosing pump-0.37KW
26. Spare
27. M-13A, Back wash Recirculation pump
28. M-12, contaminated cord, pump-7.5kW Ammonia pump 1&3
29. Reserve, Dm tank fishing
30. M-59, clarified water pump-37KW

COMPONENTS

1. RAW WATER STORAGE AND SUPPLY SYSTEM

Function:
Stores the incoming raw water and supplies it to the treatment sections. This water is typically sourced from
river water or industrial supply lines.
Components:
• Raw Water Storage Tank
• Transfer Pumps
• Strainers and Flow Control Valves Working:
Raw water is pumped from storage tanks to the Pre-treatment section. Coarse impurities like suspended solids
are removed using strainers or multimedia filters.

2. PRE-TREATMENT SECTION
Purpose:
To remove suspended solids, turbidity, organic matter, and chlorine which can damage ion exchange resins.
Major Equipment:
• Pressure Sand Filter (PSF): Removes suspended particles down to 20–40 microns.
• Activated Carbon Filter (ACF): Removes organic impurities and chlorine from the water.
Working:
Water is first passed through the PSF, followed by the ACF. The output is clarified, dechlorinated water suitable
for ion exchange.

3. CAT ION EXCHANGER (CATION UNIT)

Purpose:
Removes positively charged ions (e.g. Ca²⁺, Mg²⁺, Na⁺, Fe²⁺) through exchange with hydrogen ions (H⁺).
Resin Type:
Strong Acid Cation Exchange Resin
Chemical Reaction: 2R-H+Ca2+→R2-
Ca+2H Regeneration:
Done using Dilute Hydrochloric Acid (HCl) or Sulfuric Acid (H₂SO₄).

4. DEGASSIFIER TOWER
Purpose:
Removes carbon dioxide (CO₂) formed during the cation exchange stage which would otherwise burden the
anion exchanger.

33
Working:
Water is sprayed into a tower packed with plastic media while air is blown counter-currently. CO₂ escapes
into the atmosphere. Chemical Reaction:
HCO3−+H+→H2CO3→CO2+H2O

5. ANION EXCHANGER
Purpose:
Removes negatively charged ions such as Cl⁻, SO₄²⁻, NO₃⁻, and silica (SiO₂) by exchanging them with
hydroxide ions (OH⁻).
Resin Type:
Strong Base Anion Resin
Chemical Reaction: R-
OH+Cl−→R-Cl+OH
Regeneration:
Using Dilute Caustic Soda (NaOH).

6. MIXED BED EXCHANGER (MB UNIT)

Purpose:
Acts as a polishing unit to further reduce the conductivity and achieve very high-purity water.
Resin Composition:
Mixed bed of cation and anion exchange resins in 1:2 ratio.
Working:
Simultaneous removal of both cations and anions. It is typically used downstream of the primary DM units.
Regeneration:
Cation and anion resins are separated hydraulically, regenerated individually, then remixed.

7. RESIN REGENERATION SYSTEM

Purpose:
Restores the ion exchange resins' capacity to remove ions.
Components:
• Acid Dosing Tank (for Cation Resin)
• Alkali Dosing Tank (for Anion Resin)
• Chemical Transfer Pumps
• Regeneration Waste Collection System Neutralization:
Waste streams are neutralized before disposal using neutralization pits or chemical dosing.

8. PRODUCT WATER STORAGE TANK

Function:
Stores high-purity DM water for dispatch to high-pressure boiler systems.
Specifications:
• Conductivity: < 0.1 µS/cm
• Silica: < 0.02 ppm
• pH: 6.5–7.5

9. CONTROLAND MONITORING SYSTEM

Purpose:
Ensures quality control, process automation, and alarms.

34
Instruments Used:
• Conductivity Meters
• Silica Analyzers
• pH Sensors
• SCADA/PLC-based Control Panels

10. DM WATER APPLICATIONS AT VIZAG STEEL PLANT

• Boiler Feed Water: Prevents scaling and corrosion.
• Turbine Cooling: Ensures high efficiency and longevity.
• Descaling Operations: Used in pickling and acid cleaning. Process Water in Steel
Manufacturing Units

BOILER
A boiler is a closed vessel in which water or other fluids are heated to generate steam or hot water. The steam
or hot water produced by the boiler can be used for various purposes, including heating, power generation,
cooking, sanitation, and industrial processes. Boilers are commonly used in residential, commercial, and
industrial settings.
The basic principle behind a boiler's operation involves heating a fluid to a high temperature, which generates
steam or hot water. This is typically achieved by burning fuels such as natural gas, oil, coal, or biomass in a
combustion chamber. The heat produced from the combustion process is transferred to the water or fluid,
raising its temperature. The resulting steam or hot water is then circulated through pipes and used for its
intended applications.

35
 Fig 13: CPP Boiler Boilers

come in various types, including:

1. Fire-tube Boilers: In this type of boiler, hot gases from the combustion process pass through tubes
that are immersed in water. The heat is transferred through the walls of these tubes to the water, generating
steam.
2. Water-tube Boilers: These boilers have water-filled tubes that are heated externally by hot gases from
the combustion process. The heat is transferred from the gases to the water within the tubes, producing steam.
Boilers play a crucial role in many industries and residential settings, contributing to heating, energy
production, and various industrial processes. Proper maintenance and safety precautions are essential when
operating boilers, as they involve high temperatures and pressure, which can be hazardous if not managed.

➢ TPP has 8 boilers, 6 in CPP1 out of which 5 are in working condition and 2 in CPP2(Captive Power
Plant).
➢ These are multi fuel fired stationary and high pressure, water tube boilers with single drum.
➢ The steam produced in these boilers at full load rating is supplied to the turbine generators which
produce power by expanding steam.
➢ 6 boilers at
➢ at CPP2 have a steam flow capacity of 223Nm³/Hr.
➢ Name Of the Boiler TPP have a steam flow capacity of 330Ton/Hr.

The 2 boilers located in CPP2:

• It is a Single Drum Boiler.
• It is placed at a height of 53m and it is naturally circulated as it flows from top to bottom.
• Pipes are suspended due to heating expansion twisting may occur so they are suspended.
• It is divided into two parts one end Forced Draft fan & other end Induced Draft fan to create a balanced
draft.

• 3-stage superheating will be done (Primary, Secondary, Tertiary).

• As COG and BFG used as Fuel it is called as Multi fuel.
• Wall Firing process will be there for heating the water hence called Wall Firing
• Economizers are used for enhancing efficiency.
• As BFG & COG are completely burnt there is no residue hence it is a dry bottom
• It is a Water Tube Boiler.

BoilerAccessories:
Boiler accessories are additional devices and components that enhance the functionality, efficiency, and
overall operation of a boiler system. Unlike boiler mountings, which are primarily focused on safety and basic
operation, accessories provide supplementary features and capabilities. Here are Some common examples of
boiler accessories:
1. Economizer: An economizer is a heat exchanger that preheats the feedwater using the waste heat from
the flue gases. This increases boiler efficiency by recovering heat that would otherwise be lost.

36
2. Air Preheater: Similar to an economizer, an air preheater preheats the combustion air using the heat
from the flue gases. This improves combustion efficiency and reduces fuel consumption.
3. Superheater: A superheater is a component that further heats the steam generated by the boiler. This
increases the temperature of the steam beyond its saturation point, improving energy transfer efficiency and
allowing for more work to be extracted from the steam.
4. Deaerator: A deaerator removes dissolved gases, such as oxygen and carbon dioxide, from the
feedwater before it enters the boiler. This helps prevent corrosion and scaling within the boiler.
5. Feed water Pump: A feedwater pump is used to supply water to the boiler. It ensures a steady flow of
water and maintains the required pressure for efficient operation.
6. Chemical Dosing System: This system introduces chemicals into the boiler water to prevent scaling.
corrosion, and the formation of deposits. Proper water treatment is essential for the longevity and efficient
operation of the boiler.
7. Draft Fans and Dampers: These accessories help control the airflow and draft within the boiler
system. They ensure proper combustion and heat transfer by maintaining the right balance of air and fuel.
8. Steam Separator: A steam separator is used to separate water droplets from steam before it enters the
distribution system. This ensures that only dry steam reaches the intended destination.

Boiler Mountings:
Boiler mountings are essential safety and operational components that are mounted directly on the boiler
shell to ensure safe and controlled operation. Unlike boiler accessories, which enhance performance and
efficiency, mountings are mandatory by boiler regulations and are critical to preventing accidents,
managing pressure, and maintaining optimal operation. They help monitor the working parameters of the
boiler and provide control during normal and emergency conditions.
Here are some common boiler mountings:
1. Safety Valve:
A safety valve is a critical component that automatically releases excess steam when boiler
pressure exceeds the safe limit. This prevents potential explosions and maintains pressure within safe
operating conditions. It is calibrated to open at a preset pressure level and close once the pressure
drops.
2. Water Level Indicator:
This device shows the current water level inside the boiler. It is typically a glass tube mounted
vertically on the boiler and connected to the water space. Maintaining the correct water level is
essential to avoid overheating and potential damage to boiler tubes.
3. Pressure Gauge:
A pressure gauge displays the steam pressure inside the boiler. It is usually a Bourdon-type
gauge, calibrated in psi, bar, or kg/cm². The operator uses it to monitor pressure and ensure it remains
within safe limits.
4. Steam Stop Valve:
This valve controls the release of steam from the boiler to the main steam pipe. It acts like a steam
switch, allowing or stopping the flow of steam to the engine, turbine, or process system.

37
5. Feed Check Valve:
The feed check valve allows feedwater to enter the boiler and prevents backflow from the boiler to the
feed line. It typically includes a non-return valve and a hand-operated control valve.
6. Blow-off Cock (or Blow-down Valve):
Used to remove sediment, sludge, and scale from the bottom of the boiler, the blow-off cock helps
maintain boiler cleanliness and reduces corrosion. It is operated periodically to discharge dirty water
and impurities.
7. Fusible Plug:
A fusible plug is a safety device that prevents damage due to low water levels. It contains a low
melting point alloy that melts when exposed to excessive heat, releasing steam or water into the
furnace and extinguishing the fire, preventing tube failure.
8. Manhole and Mudhole Doors:
These are access openings for internal inspection, cleaning, and maintenance of the boiler. Manholes
are large enough for a person to enter the boiler, while mudholes are smaller and usually located at
the bottom of the boiler to remove sludge and mud.

Fig 14: Boiler Water Circuit Overview

38
 Fig 15: Steam Boiler Diagram

STEAM TURBINE

i) Introduction
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam
and converts it into rotary motion. It plays a vital role in power generation, particularly in thermal power
plants, where steam produced in boilers is expanded in turbines to produce mechanical power, which is then
converted into electricity using an alternator. Steam turbines are preferred over reciprocating engines due to
their higher efficiency, reliability, and ability to handle high pressure and temperature conditions. The basic
working principle of a steam turbine is the conversion of the thermal energy of steam into kinetic energy by
expanding the steam through nozzles and then using that kinetic energy to rotate blades mounted on a shaft.

Classification of Steam Turbines

Steam turbines can be classified based on several criteria: a)
Based on the direction of steam flow:
• Axial Flow Turbine: Steam flows parallel to the axis of the rotor.
• Radial Flow Turbine: Steam flows in a radial direction perpendicular to the axis. b) Based on
the pressure of steam:
• High-Pressure Turbines
• Medium-Pressure Turbines
• Low-Pressure Turbines

39
c) Based on the principle of operation:
• Impulse Turbine: Steam expands completely in nozzles and hits the blades with high velocity, causing
rotation (e.g., De Laval turbine).
• Reaction Turbine: Expansion of steam takes place both in fixed and moving blades. The steam causes
a reactive force that drives the rotor (e.g., Parsons turbine).
d) Based on the number of stages:
• Single-stage Turbine
• Multi-stage Turbine
e) Based on steam conditions:
• Condensing Turbine
• Non-condensing (Back-pressure) Turbine
• Reheat Turbine
• Extraction Turbine

ii) Steam Turbine Construction and Blade Mechanism

A steam turbine consists of several critical components designed to handle high-speed rotation and thermal
stresses. The key parts include:
• Casing: The outer housing that contains steam and supports the internal components. It is usually made
of cast steel or alloy steel.
• Rotor (Shaft): A central rotating shaft on which turbine blades are mounted. It is connected to a
generator or mechanical load.
• Blades: These are mounted on the rotor and play a crucial role in converting steam energy into
mechanical energy. They are of two types:
o Fixed Blades (Nozzles): These direct and accelerate the steam.
o Moving Blades: These receive the steam impulse or reaction force and rotate the rotor.
In impulse turbines, blades change the direction of steam flow and absorb kinetic energy, while in reaction
turbines, steam expands in both fixed and moving blades, utilizing both pressure and velocity changes.
• Bearings: Support the rotor and help reduce friction during rotation.
• Seals: Prevent leakage of steam from high-pressure zones to low-pressure zones.
The efficiency and output of a steam turbine largely depend on the blade design and arrangement. Modern
turbines use advanced blade profiles and materials to withstand high temperatures, corrosion, and erosion.

iii) Governing of Steam Turbines

Governing refers to the method of controlling the speed and power output of the steam turbine in response to
changing load demands. It ensures safe, efficient, and stable operation by maintaining a constant speed despite
load fluctuations.

40
Types of Governing:
1. Throttle Governing: Controls steam flow by adjusting a throttle valve at the turbine inlet. Common
in smaller turbines; simple but causes pressure loss.
2. Nozzle Control Governing: Controls steam by opening or closing groups of nozzles. Used in impulse
turbines. Efficient due to minimal pressure loss.
3. Bypass Governing: Excess steam is directed to later turbine stages during load surges. Helps in load
balancing without disturbing initial stages.
4. Combination Governing: Uses throttle and nozzle control together for finer regulation and high
efficiency, especially in large power plants.

Components of the Governing System:

• Governor Valve
• Centrifugal or Electronic Governor
• Linkage Mechanism
• Sensors and Actuators (in modern systems)

Efficient governing prevents overspeed, enhances load handling, and contributes to the safe and stable
operation of turbines.

Fig 16: Internal Rotor of Steam Turbine

41
Fig 17: Guide Blades of a Steam Turbine

42
 Fig 18: CPPTurbine

Fig 19: Steam Flow

iv) Turbo Generators:

43
A turbo generator is a combination of a steam turbine and an electric generator, used to convert mechanical
energy produced by the turbine into electrical energy. It is a core component in thermal power plants, where
steam generated in boilers is used to drive turbines, which in turn drive generators to produce electricity.

Working Principle
The working of a turbo generator is based on Faraday’s Law of Electromagnetic Induction, which states that
when a conductor moves through a magnetic field, an electromotive force (EMF) is induced in it. In a turbo
generator:
1. High-pressure steam from the boiler is directed onto the blades of the steam turbine.
2. The turbine rotor spins at high speed (usually 3000 RPM in a 50 Hz system) due to the force of steam.
3. The rotating turbine is mechanically coupled to the generator rotor.
4. As the generator rotor spins inside a stator with windings, it creates a rotating magnetic field.
5. This changing magnetic field induces an alternating current (AC) in the stator windings, which is then
transmitted as electrical power.

Construction of Turbo Generator

A turbo generator consists of the following main parts:
• Turbine Section:
o Includes nozzles, rotor, blades, and casing.
o Converts thermal energy of steam into mechanical rotation.
• Generator Section:
o Rotor (Field Winding): Connected to the turbine and acts as an electromagnet. o Stator
(Armature): Stationary part with windings where electricity is induced. o Bearings: Support
the rotating shaft and reduce friction.
o Cooling System: Essential to remove heat generated due to high-speed rotation. Air, hydrogen,
or water cooling is commonly used.
o Excitation System: Provides DC power to the rotor to create a magnetic field.
Types of Turbo Generators:
1. Air-Cooled Turbo Generators: Used for small and medium capacities.
2. Hydrogen-Cooled Turbo Generators: Used for larger units due to hydrogen’s high heat-carrying
capacity and low resistance.
3. Water-Cooled Turbo Generators: Applied in very large power stations to enhance cooling efficiency.

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 CHILLED WATER PLANT

Chilled water plants that use cooling towers are a common setup for providing cooling to large buildings,
industrial facilities, and other applications where a significant amount of cooling is required. Cooling towers
are an integral part of these systems as they help dissipate the heat absorbed by the chilled water from the
building's air conditioning system. Here's how a chilled water plant with cooling towers works:
1. Chiller Operation and Chilled Water Generation: The process begins with a chiller, which cools
water to a low temperature. The chiller's evaporator absorbs heat from a water loop, producing chilled water.
2. Chilled Water Distribution: The chilled water is then pumped through a distribution system of pipes
to different areas of the building or facility that require cooling.
3. Cooling Towers: As the chilled water absorbs heat from the indoor spaces, its temperature increases.
This warmer chilled water is then sent to cooling towers.
4. Heat Exchange and Evaporation: In the cooling tower, a process called evaporation cooling takes
place. The warm chilled water is distributed over a series of fill material, which increases the surface area for
air and water interaction. Air is blown through the fill material, causing a portion of the water to evaporate.
This evaporation process removes heat from the remaining water, significantly reducing its temperature.
5. Heat Dissipation: The heat that was initially absorbed from the building is carried away by the air as
water evaporates. This cooled water, now referred to as "cooled return water," is then sent back to the chiller
plant to be reused in the cooling cycle.
6. Condenser Water Loop: In addition to the chilled water loop, there's a separate loop called the
condenser water loop. This loop collects hot water from the chiller's condenser, where the heat absorbed from
the building's air is released. The hot condenser water is sent to the cooling towers.
7. Cooling Tower Airflow: The cooling tower's fans draw ambient air through the fill material,
facilitating the heat exchange and evaporation process. The warm, moist air exit the cooling tower, and some
of the evaporated water may be visible as a plume of vapour.
8. Heat Rejection and Cycle Completion: As the hot condenser water flows through the cooling tower,
it releases heat to the surrounding air via evaporation and convection. The cooled condenser water then returns
to the chiller's condenser, completing the cycle.
In the boilers, the water from these cooling towers goes into the hot well which cools the water formed in the
condenser.

CHEMICALWATER TREATMENT

A chemical water treatment plant in boilers is a system designed to treat and condition water used in boilers
to prevent scale formation, corrosion, and other issues that can arise due to the presence of impurities and
minerals in the water. Proper water treatment is essential to ensure the efficient and safe operation of boilers,
as untreated water can lead to reduced efficiency, equipment damage, and even boiler failure.
The primary goals of a chemical water treatment plant for boilers are:
1. Scale Prevention
2. Corrosion Protection

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 3. pH Adjustment
4. Oxygen Scavenging
5. Control of Suspended Solids
6. Control of Alkalinity and Hardness
7. Biologica; Control
The specific chemicals and treatment methods used depend on the type of boiler, the quality of the feedwater,
and the operational requirements. Regular monitoring of water quality and treatment effectiveness is crucial
to ensure that the chemical water treatment plant is functioning as intended.
It's important to note that improper chemical treatment can have negative consequences, including increased
corrosion, equipment damage, and even safety hazards. Therefore, water treatment should be carried out by
trained professionals following industry standards and guidelines.

CONDENSATION:
Condensation is the process which involves the transformation of a substance from a gaseous state to a
liquid state as it loses heat. This occurs when a gas cools down and its molecules lose energy, causing them
to come closer together and form a liquid.
Key points about condensation include:
1. Temperature Reduction
2. Surface Nucleation
3. Cloud Formation
4. Phase Transition
Condensation is a common occurrence in everyday life, and it’s an essential process in various natural and
industrial contexts.

CONDENSATION OF WATER:
The condensation of water refers specifically to the process by which water vapor in the air transitions back
into liquid water as it cools down. This is a fundamental aspect of the water cycle, which involves the
continuous movement of water between the Earth's surface, the atmosphere, and back again.
The condensation of water is a crucial process that influences weather patterns, cloud formation, and the
distribution of water resources on Earth. It's intimately connected with other phases of the water cycle, such
as evaporation, sublimation, and precipitation, and it plays a vital role in maintaining the Earth's ecosystems
and climate.

WATER DEMINERALIZATION
Water demineralization, also known as deionization, is a process that removes mineral ions and impurities
from Water resulting in highly purified water with a very low concentration of dissolved solids. This process
is commonly used in various industries, laboratories, and applications where ultra-pure water is required.
The primary goal of water demineralization is to eliminate or reduce the presence of minerals, salts, and
other charged particles in water. This is often achieved through two main methods: ion exchange and
membrane filtration.
1. Ion Exchange: Ion exchange involves passing water through a resin bed containing ion exchange
resins. These resins are designed to attract and capture ions present in the water. Cations (positively charged
ions) and anions (negatively charged ions) are exchanged for hydrogen ions (H+) and hydroxide ions(OH-)

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respectively, as water passes through the resin bed. The result is water with significantly reduced
concentrations of minerals and ions.
2. Membrane Filtration: Membrane filtration methods’ such as reverse osmosis (RO) and
electrodialysis, use semipermeable membranes to selectively allow water molecules to pass through while
blocking larger ions and impurities. Reverse osmosis, in particular, is effective at
3. Chemical Processes: Many chemical reactions and processes require water with controlled levels of
ions to ensure accurate results.
It’s important to note that while water demineralization removes minerals and impurities, it also removes
beneficial minerals that are essential for human health. As a result, demineralized water is not suitable for
human consumption on its own, as it lacks essential electrolytes and minerals. In cases where water is
intended for drinking, additional treatment or re mineralization may be necessary to make it safe and
healthy for consumption.

Fig 20: DM water Flow

SAFETY DEVICES AND AUTOMATION

The Captive Power Plant (CPP) at RINL - Vizag Steel Plant plays a critical role in supplying
uninterrupted and efficient power to the integrated steel manufacturing units. Given the scale
and complexity of operations, stringent safety mechanisms and advanced automation
systems are employed to ensure safe, reliable, and optimized performance.

1. Safety Devices in CPP – Vizag Steel Plant

RINL-VSP employs a range of safety devices integrated into every aspect of CPP
operations, especially in high-pressure boiler and turbine units. a) Pressure Relief and
Safety Valves

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 • Installed on boilers and steam lines to automatically release excess pressure.
• Prevents equipment damage or explosions due to overpressure situations.
b) Flame Scanners and Safety Interlocks
• Used in boiler combustion chambers to detect flame presence.
• Automatically cut off fuel supply during flame failure to avoid gas accumulation and
explosion.
c) Boiler Drum Level Indicators with Alarms
• Continuously monitor the water level in the boiler drum.
• Low or high levels trigger alarms and interlock shutdowns to protect boiler tubes from
overheating or water carryover.
d) Emergency Shutdown System (ESD)
• Integrated into all critical equipment (boilers, turbines, generators).
• Triggers instant shutdown under unsafe conditions like over-speed, low lubrication
pressure, or high vibration.
e) Gas and Fire Detection Systems
• Since COG (Coke Oven Gas) and BFG (Blast Furnace Gas) are used as fuels, gas leak
detectors are installed.
• Fire detectors, flame sensors, and manual call points are provided throughout CPP.
• Water-based fire hydrant systems and CO₂ flooding systems are in place for fire
emergencies.

f) Turbine Protection Mechanisms

• Over-speed trip devices, bearing temperature sensors, and vibration monitors protect the
turbine from mechanical failure.
• Emergency oil injection systems ensure lubrication in case of pump failure.

2. Automation in CPP – Vizag Steel Plant

Automation systems at Vizag Steel’s CPP enhance operational reliability and efficiency
through centralized monitoring, real-time control, and diagnostics. a) Distributed Control
System (DCS)
• All boiler, turbine, and generator operations are controlled via a centralized DCS.

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 • Parameters such as steam pressure, fuel flow, drum level, turbine speed, and generator
output are continuously monitored.
• Offers auto/manual modes, alarm management, and historical data trending.
b) Programmable Logic Controllers (PLCs)
• Control specific sub-processes like fuel handling systems (coal conveyors, crushers), ash
handling, and pump operations.
• Enable quick logic-based decisions for smooth functioning and fault detection. c)
SCADA Integration
• CPP is integrated with the SCADA system of the main plant.
• Provides real-time data visualization, remote control capability, alarm logs, and
performance reports.
d) Turbine Control System (TCS)
• Ensures precise control of turbine load and speed.
• Provides trip signals during abnormal conditions like excessive vibrations, lubrication
failure, or generator faults.
e) Automatic Combustion Control (ACC)
• Manages the air-to-fuel ratio for efficient and clean combustion of COG and BFG.
• Coordinates with draft fans, dampers, and fuel flow valves for optimal boiler operation.

f) Predictive Maintenance and Condition Monitoring

• Vibration sensors, temperature probes, and oil analyzers help predict component wear
and potential failures.
• Facilitates condition-based maintenance, reducing downtime and
improving equipment longevity.

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ENVIRONMENTALAND POLLUTION CONTROL MEASURES

The Captive Power Plant (CPP) at Rashtriya Ispat Nigam Limited (RINL) – Vizag Steel Plant operates
with a strong commitment to environmental sustainability. As power generation involves the combustion of
fuels like Coke Oven Gas (COG) and Blast Furnace Gas (BFG), it is essential to implement robust
pollution control and environmental management practices. The CPP integrates modern technologies and
management strategies to minimize its environmental footprint and adhere to regulatory standards.

1. Air Pollution Control Measures

a) Electrostatic Precipitators (ESP)
• Installed in boiler exhaust systems to capture particulate matter (PM) before flue gases are released
into the atmosphere.
• Achieves dust collection efficiency of over 99%, minimizing fly ash emissions.
b) Flue Gas Desulphurization (FGD) System
• Used for removing sulfur dioxide (SO₂) from flue gases.
• Wet or dry scrubbing techniques reduce acid rain-causing pollutants.
c) Low-NOx Burners and Staged Combustion
• Reduces nitrogen oxides (NOx) formation during fuel combustion.
• NOx emissions are major contributors to smog and respiratory problems.
d) Stack Monitoring Systems
• Continuous Emission Monitoring Systems (CEMS) are installed on stacks to monitor SOx, NOx, CO,
and PM emissions.
• Helps maintain compliance with Central Pollution Control Board (CPCB) norms.

2. Water Pollution Control Measures

a) Effluent Treatment Plant (ETP)
• Treats wastewater from boilers, cooling towers, and other plant areas.
• Removes oil, suspended solids, and chemicals before discharge or reuse.
b) Zero Liquid Discharge (ZLD) Approach
• Maximizes water reuse through recycling and evaporation.
• Reduces the need for freshwater intake and prevents contamination of water bodies.
c) Cooling Tower Blowdown Management
• Cooling water systems are monitored to control scale and corrosion.

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 • Blowdown water is treated and reused wherever possible.

3. Solid Waste Management

a) Ash Handling System
• Dry and wet systems are used to handle bottom ash and fly ash from boilers.
• Ash is transported in a controlled manner to ash ponds or reused in construction (e.g., cement, bricks).
b) Sludge Disposal
• Sludge from water and effluent treatment plants is dewatered and disposed of in an environmentally
safe manner.
c) Waste Segregation and Recycling
• Metal scraps, insulation materials, and packaging waste are segregated and sent to recycling units.

4. Noise Pollution Control

• Acoustic enclosures are installed around high-noise equipment like turbines and compressors.
• Green belts and noise barriers help reduce ambient noise levels around the plant boundary.
• Periodic monitoring is carried out to ensure compliance with prescribed noise level norms.

5. Green Initiatives and Carbon Footprint Reduction

a) Waste Heat Recovery
• Heat from flue gases is recovered using economizers and preheaters to improve efficiency and reduce
fuel consumption.
b) Use of By-product Gases
• COG and BFG, which are by-products from steelmaking, are utilized as fuels, reducing dependence
on fossil fuels and lowering CO₂ emissions.
c) Tree Plantation and Green Belt Development
• Extensive afforestation and maintenance of green cover around the CPP.
• Acts as a natural barrier against air and noise pollution.
6. Environmental Monitoring and Compliance
• Continuous Ambient Air Quality Monitoring Stations (CAAQMS) are installed around the plant.
• Regular environmental audits and reports are submitted to regulatory authorities.
• Environmental Management System (EMS) in place as per ISO 14001 standards.

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 CONCLUSIONS

The Thermal Power Plant (TPP) at Vizag Steel Plant, particularly in relation to the Demineralization (DM)
plant, exemplifies an integrated and efficient power system configuration tailored to meet the rigorous
demands of steel manufacturing. This study highlights the seamless coordination of key components such as
the Rankine Cycle, boilers, turbines, and turbo-generators, all of which are essential for consistent and
reliable power generation.
The DM plant plays a vital support role by supplying high-purity water critical for boiler and turbine
operation, ensuring system longevity and efficiency. Detailed exploration of fuel handling systems,
combustion methods, and advanced control mechanisms demonstrates the plant's commitment to operational
excellence.
Furthermore, the integration of automation and real-time monitoring ensures optimal performance and safety.
Vizag Steel Plant’s adoption of robust pollution control systems and sustainable practices underscores its
commitment to environmental responsibility.
Overall, the power system configuration within the TPP at Vizag Steel Plant showcases a balanced approach
to engineering innovation, energy efficiency, and environmental stewardship—serving as a benchmark for
captive power systems in large-scale industrial operations

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