nfl bathinda training file

NATIONAL FERTILIZERS LIMITED

SBSSTC, Ferozepur

INDUSTRIAL TRAINING REPORT

(Four Months)

PUNJAB TECHNICAL UNIVERSITY

SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE

AWARD OF THE DEGREE O F

BACHELOR OF TECHNOLOGY

SUBMITTED BY

Rahul Chadha Roll No. 1250718 (Batch 2012)

AUGUST – DECEMBER 2015

Mechanical Engineering

Shaheed Bhagat Singh State Technical Campus

Moga Road, Ferozepur-152004

mailto:[email protected]

http://www.sbscet.ac.in/

http://www.sbscet.ac.in/

i

DECLARATION

Signature of the STUDENT (Roll No.: . . . . . . . . . . . . )

This is to certify that the above statement made by the candidate is correct to the best of

my/our knowledge.

Signature of the TRAINING & PLACEMENT OFFICER, ME

The INDUSTRIAL TRAINING Viva-Voce Examination of RAHUL CHADHA has been held on

. . . . . . . . . . . . and accepted.

Signature of the EXTERNAL EXAMINER

Signature of the HEAD, DEPARTMENT OF ME

iii

ABSTRACT

The main idea behind the establishment of NFL, Bathinda is to manufacture and marketing of Urea

and Neem Coated Urea.

For the production it has five sections :

1. Ammonia Plant

2. Urea Plant

3. Captive Power Plant

4. Steam Generation Plant

5. Off-sites and Utilities

Place: Bathinda Rahul Chadha

Date: 3 August, 2015

iv

AKNOWLEDGEMENT

The industrial training in an industry/project site is an essential part of curriculum for completion

of degree. I am grateful to authorities at National Fertilizer Limited, Bathinda for permitting me

to undergo six month industrial training in their esteemed organization. During this training I have

learnt a lot for which I pay heartiest gratitude to Mr. Kulwant Singh (Sr. Manager of HRD) ,

Mr. Rajesh Maurya (Deputy Manager) and staff member of NFL Bathinda who helped in all

respects in fulfilling my cherished desired of getting a successful industrial training .

Place: Bathinda Rahul Chadha

Date: 3 AUGUST, 2015

v

CONTENTS

Declaration………………………………………………….......……………………………………i

Certificate………………………………………………………......…………………………....….ii

Abstract…………………………………………………………......……………….………...........iii

Acknowledgements……………………………………………………......…….……….………....iv

List of Figures………………………………………………….....………….…………….............vii

List of Tables…………………………………………………….....………………….……...…..viii

Abbreviations………………………………………………………......………………….….….....ix

Chapter 1: Introduction to organization……………………………………......…………….……...1

1.1 Brief introduction of Organization………………………………......…………………1

1.2Salient features of Bathinda Unit…………………………………......……………...…2

Chapter 2: Production sections……………………………………………….....……...……….......3

2.1 Ammonia Plant………………………………………………….....……...……….…..3

2.2 Urea Plant…………………………………………………………......……...…....…...8

2.3 Captive Power Plant……………………………………………………...….....….....11

2.4 Steam Generation Plant………………………………………………...…….............17

2.5 Off-sites and Utilities………………………………………………………….....…..20

2.6 Pumps………………………………………………………………………….....…..22

2.7 Compressor……………………………………………………………………......…25

2.8 Maintenance………………………………………………………………….......…..28

Chapter 3: Project Review………………………………………………………………..….....….30

3.1 Objective…………………………………………………………………..…....….…30

3.2 Review…………………………………………………………………..…….....…...30

3.3 Observations deduced ………………………………………………..………......…..30

Chapter 4: Project Work…………………………………………………………..……....…….…31

4.1Study of Turbine, Nozzle ,Condenser and Turbo-Generator…….....….…………......31

4.2Study of Feed water heater and Feed water Control station……..…………….....…35

4.3Study of Boilers…………………………………………………..……………....….37

Chapter 5: Results and Discussions…………………………………………..……………....……39

5.1 Observations…………………………………………………..………...……....……39

5.2 Layout of Captive Power Plant and Steam Generation Plant..………..……….....…..40

vi

Chapter 6: Cautions during Problems...............................................................................................41

6.1 High Condenser Level..................................................................................................41

6.2 Polish water failed from DM plant...............................................................................41

6.3 TG Vibration High........................................................................................................41

6.4 Steam Temperature is low.............................................................................................42

6.5 Exhaust temperature High/Vacuum low.......................................................................42

Chapter 7: Conclusion.......................................................................................................................43

Bibliography.....................................................................................................................................44

vii

List of figures:

Fig 1.1 Production Performance........................................................................................................2

Fig 2.1 Block diagram of Ammonia Plant..........................................................................................7

Fig 2.2 Block diagram of Urea Synthesis...........................................................................................9

Fig 2.3 Urea Synthesis......................................................................................................................10

Fig 2.4 Water tube Boiler..................................................................................................................13

Fig 2.5. Shows General concept of power generation by Steam turbine..........................................14

Fig. 2.6 Cooling Tower.....................................................................................................................21

Fig 2.7 Rotary Pump.........................................................................................................................22

Fig 2.8 Centrifugal Pump..................................................................................................................23

Fig 2.9 Reciprocating Pump.............................................................................................................24

Fig 2.10 Reciprocating Compressor.................................................................................................26

Fig 2.11 Axial Flow compressor.....................................................................................................27

Fig 4.1 Steam passing through turbine.............................................................................................31

Fig 4.2 Shows steam processed through Turbine to boiler...............................................................32

Fig 4.3 shows 3D view of nozzle partitions and buckets placing.....................................................33

Fig 4.4 Sectional view of condenser.................................................................................................33

Fig 4.5Feed water heater...................................................................................................................35

Fig 4.6 feed water control station layout..........................................................................................36

Fig 4.7 sectional view of boiler........................................................................................................37

Fig. 4.8 Economizer..........................................................................................................................38

Fig. 5.1 Layout of Captive Power Plant and Steam Generation Plant.............................................40

viii

List of tables:

Table 2.1 Shows the sections of Ammonia Plant and its features.....................................................3

Table 2.2 Shows Compressor in Ammonia Plant and its features......................................................4

Table2.3 Showing configurations of turbine.....................................................................................15

Table 4.1 TG operating parameters before and after Overhauling ..................................................34

Table 5.1 Boiler operation requirements...........................................................................................39

Table 5.2 Temperature of steam/water.............................................................................................39

Table 5.3Spray water quantity..........................................................................................................39

ix

List of abbreviations used:

TG- Turbo-Generator

H.P heater- High Pressure heater

L.P heater- Low Pressure heater

H.T.S.H- High Temperature Superheater

I.TS.H- Intermediate Temperature Superheater

L.T.S.H- Low Temperature Superheater

Press.- Pressure

Temp. – Temperature

CV- Control Valve

SV-Spring Valve

FWT- Feed Water Tank

BFW- Boiler Feed Water

4 Months Industrial Training

Shaheed Bhagat Singh State Technical Campus, Ferozepur 1

Chapter 1

Introduction to organization

1.1 Brief introduction of Organization:

NFL, a Schedule „A‟ & a Mini Ratna (Category-1) Company, having its registered office at New

Delhi was incorporated on 23rd August 1974. Its Corporate Office is at NOIDA (U.P). It has an

authorized capital of ₹1000 crore and a paid up capital of ₹490.58 crore out of which Government

of India‟s share is 90% and 10% is held by financial institutions & others.

NFL has five gas based Urea plants viz Nangal & Bathinda in Punjab, Panipat in Haryana and two

plants at Vijaipur in District Guna, Madhya Pradesh. The above plants at Panipat, Bathinda &

Nangal which were earlier based on fuel oil (LSHS) have recently been converted on Natural Gas,

an eco-friendly fuel. Vijaipur plants of the company were also revamped for energy savings &

capacity enhancement during 2012-13, thus increasing its total annual capacity from 20.66 LMT

from 17.29 LMT, an increase of 20%. The company has a total annual installed capacity of 35.68

LMT and is the 2nd largest producer of Urea in the country with a share of about 16% of total Urea

production in the country. The products being manufactured and sold by NFL under brand name

„KISAN' include Urea, Neem Coated Urea, Bio-Fertilizers (solid & liquid). Besides manufacturing

of fertilizers, the company is also producing allied Industrial products like Nitric Acid, Ammonium

Nitrate & Ammonium Nitrite, Sodium Nitrite, Sodium Nitrate etc. The company is also

endeavoring trading of imported fertilizers like DAP, MoP etc. The Company is also in the process

of setting up a Bentonite Sulphur plant at its Panipat Unit to cater the requirement sulphur deficient

soil. NFL has a wide marketing network across major part of India comprising of a Central

Marketing Office at NOIDA, three Zonal Offices at Bhopal, Lucknow & Chandigarh, 12 State

Offices and 38 Area Offices. NFL has been mandated to revive the closed plants of Fertilizer

Corporation of India Limited (FCIL) at Ramagundam in collaboration with M/s EIL and M/s FCIL

by setting up a Urea plant of annual capacity of 12.71 LMT for which a Joint Venture (JV)

Company has been formed as Ramagundam Fertilizers & Chemicals Limited (RFCL). Currently,

various pre-project activities are in full swing.Presently, company has a total manpower of 3843

employees.



1.2Salient features of Bathinda Unit

Installed Capacity: 511500 MTPA

Capital Investment: 349.41 Crores

Initial

Commencement of

Production:

October 1, 1979

Commencement of

Production on Gas

after Revamp:

March 11, 2013

1.2 Process

Ammonia: HTAS Steam Methane Reforming (SMR) Technology

Urea: Mitsu Toastsu total Recycle C Improved

Raw material: Coal , LNG/ RLNG, Power, Water

Captive Power

Plant: 2 x 15 M

Fig.1.1 Production Performance



Chapter 2

Production sections

2.1 Ammonia Plant

The ammonia plant NFL Bathinda is based on partial oxidation of fuel oil. The Ammonia Plant

has the following processing units:-

Table 2.1 Shows the sections of Ammonia Plant and its features

Sr. No. Unit/section Supplier Features

1. Air separation unit M/S HITACHI

JAPAN

Mol. Sieve and

activated alumina gel

bed for CO2 &

moisture removal, cold

recovery from the

products in plate and

fin type heat

exchangers and

conventional double

column for distillation

2. Gasification M/S TEC under

process licence from

m/S SHELL

INTERNATIONAL

Refractory gasifiers of

series 700.

3. Recti sol(de-

sulphurisation)

M/S TEC under

process license from

M/S LURGI

Selective absorption of

H2S and CO2 by low

temperature methanol

4. Recti

sol(decarbonisation)

M/S TEC under


M/S LURGI

Total rergeneration

ofpartial steam only



5. CO shift M/S TECH Double bed high

temperature CO shift

converter.

6. Absorption

refrigeration

M/S BORSIG Part of heatis supplied

by the converted gas

from shift converter.

7. Nitrogen wash unit M/S HITACHI Mol. Sieve adsorbers

for removal of

methanol and CO2

8. Ammonia Synthesis M/S TEC under


M/S HALDOR

TOPSOE

Topsoe S-100 radial

flow basket, waste

heat recovery of the

converter exit gases in

BFW economizers

The compressor of ammonia plant has the following major equipment:-

Table 2.2 Shows Compressor in Ammonia Plant and its features

Sr. no. Section Supplier Features

1. Air compressor M/S MITSUI JAPAN 1,40,000NM3/hr

capacity 15.45 KW

turbine

2. Nitrogen compressor -do- 30,000 NM3/hr

capacity 6.9 MW

turbine6.9

3. Oxygen compressor Compressor-DEMAG

Turbine-AEG

24,970 N3/hr capacity

6.59 MW turbine

4. Synthesis compressor BHEL Hyderabad 1,10,000 NM3/hr

capacity 2.8MW

turbine

Against the rated capacity of 900Te/day , plant has produced a record production of 1011Te and

has been constantly running above 105% for past few years. The harmless gases like CO2 and are



vented through a cold flare outlet of 80m height. The toxic gases are burnt so that there

combustion products are not harmful to the environment.

2.1.1 Process description of Ammonia Plant:

Various process involved for the production of Ammonia are as follows:

i) Air Separatioin Unit (A.S.U.):

Air has following composition:

Nitrogen 78.03%

Oxygen 20.93%

Argon 0.93%

Carbon 0.93%

It is provided for getting oxygen and nitrogen required for production of NH3 from air is the first

section from atmosphere and is pre-cooled. Then further cooled in air chiller. Then moisture and

dust etc. are removed by passing through alumunia molecular seves. Final products i.e. N2 and O2

are obtained when air is rectified in the rectifying column. Product O2 is the first compressed and

then led to reactors in shell gasification process. For partial oxidation of food stock for producing

raw gas is separated toH2, H2S and CO2, CO2 is send to the urea plant, H2S is sent to sulphur

recovery plant. On the other hand N2 and H2 are given to N.W.U. in the ratio of 1:3 to get pure

synthesis gas to manufacture NH3.

ii) Shell Gasification and Carbon Recovery:

Lines of O2 feedback and stream led to the gasifier column where in the presence of high

temperature of the order 13500 C produce raw gas containing CO, H2S, HCN, heat is generated in

this unit. This heat is not washed but utilized to produce steam in the waste boiler.Some unburnt

carbon is also present along with other gases in raw gas, as it can check the line. It is removed by

stages water wash and there is final scrubbing stage. HCN is also removed in this stage.



iii) De-Sulphurisation:

Sulphur compound are removed in this section because otherwise these poison the catalyst present

in the next section. Methanol has a property of absorbing different gases at different temp.

Absorption process is carried out at low temp. and high pressure, H2O and COS are removed in the

raw gas to only 0.1 PPM in this unit by absorbing with MeOH. MeOH is regenerated by N2 by

stripping and H2S is sent to sulphur recovery plant.

iv) Shift Converter:

In this unit get CO2 and H2 from CO and steam at high temp. by passing the gas catalyst as per the

following reaction:

CO(g) +H2O(steam) ......... H2 + CO2

In this industrial method of producing H2 as per le chatlier principle for high concentration of

product excess is to be introduced and temp. should kept low and reaction rate is high. So

compromise is made and temp. is around 350-500 oC. Fe is used as catalyst in reaction.

v) CO2 Removal:

In this unit we get a mixture of gas(H2, CO2) from shift conversion and CO2 is removed from H2

by absorbing CO2 with methanol of low temp. This mixture of MeOH and CO2 is stripped by N2

where CO2 is regenerated and send to UREA PLANT, in this unit we get 98% of H2 and send to

N.W.U.

vi) Nitrogen Wash Unit (N.W.U.):

Even a little of CO still remains in raw gas after the shift convertor process. This is removed in

N.W.U. where liquid N2 is sprayed on raw gas of 98% H2 from the top of the tank. Before leaving

this section, purified H2 gas is mixed with N2 in the ratio 3:1 and forms an admixture without

reaction, it is called synthesis gas.



Fig. 2.1 Block diagram of Ammonia Plant

vii) Ammonia Synthesis Section

The synthesis gas from N.W.U. is compressed from 37 kg/cm2 to 230 kg/cm

2 in the centrifugal

type synthesis compressor. Then the gas enters the synthesis hot exchanger with hot effluent gas

from synthesis economizer. At the outlet of the compressor the gas contains 16% ammonia.

N2 + 3H2 …………… 2NH3



2.2 Urea Plant:

2.2.1 Conventional Process:

Mole Ratio:

NH3:CO2 4:1

H2O :CO2 0.54:1

%Conversion 70%

2.2.2 Reaction Condition:

Pressure:

CO2 250 kg/cm2

Carbonate 250 kg/cm2

Ammonia 250 kg/cm2

Temperature: 2000 C

2.2.3 Urea process classified into four sections:

i) Synthesis section.

ii) Decomposition section.

iii) Crystallization & Prilling section.

iv) Recovery section.

2.2.4 About Urea :

Urea is an Organic compound. Its chemical formula is NH2-CO-NH2

Properties of Urea:

Melting point at 1 atm: 132.47°C

Nitrogen content: 46.6 %

Color: white

Raw material requirement for Urea production

Liquid Ammonia (NH3)

Carbon Di-Oxide (CO2)



2.2.5 Advantages of Urea

1. Nitrogen content is highest among various nitrogenous fertilizers (46%).

2. Cheapest fertilizer from transportation point of view

3. CO2 which is one of the raw materials for the manufacture of urea is available at negligible cost

from ammonia plant.

4. It is not subject to fire or explosion hazard

5. It has got better flowing characteristics

6. As such it is not toxic and used in preparation of various types of medicines and in other

industries.

2.2.6 Urea Synthesis Reaction:

2NH3 liq. + CO2 = NH2-COO-NH4 + Heat (37.64 Kcal/mole) Fast & exothermic

Ammonium Carbonate

NH2-COO-NH4 = NH2-CO-NH2 +H20 - Heat (6.32 kcal/mole) slow & endothermic

Urea

Fig.2.2 Block diagram of Urea Synthesis



Carbon dioxide from battery limit at 1.02 Kg/cm2 is compressed to 30 Kg/cm2 in a 3-stage

centrifugal booster compressor which runs at 4730 kw and 7930 rpm. After first stage of

compression the compressed air goes to the intercooler and then to heat exchanger and comes back

for the second stage compression then again to the intercooler and then again to the heat

exchanger. The lubrication is provided by mobile oil.The compressed air at 30 Kg/cm2 is sent to

the 2-stage reciprocating kobe compressor in which air is firstly compressed to 90 Kg/cm2 to 250

Kg/cm2. Stage 1 consists of two cylinders and stage 2 consists of one cylinder. Now this

compressed carbon dioxide is sent for reactor.

Ammonia from battery limit is send for reciprocating pump which are 4 in number (4th being stand

by) to be compressed. Large pumping action of pumps is achieved by 400 Kw,3300V Electric

motor. The turbulent liquid is stabilized in spherical shaped resonator. now compressed NH3 is

sent to the reactor at around 200 Kg/cm2.

2.2.7 Reactor Outlet :

Carbamate pumps are required for pumping the recycle carbamate solution coming at the suction

pressure of 24 Kg/cm2 and discharge pressure of 260 Kg/cm2. These are 8 stage centrifugal pumps

with casing design pressure of 308 Kg/cm2. There are two such pumps out of which one is stand

by. In order to handle corrosive carbamate solution, all components are made up of austenitic and

ferritic duplex stainless steel. All the wearing parts are chromium plated.

Fig 2.3 Urea Synthesis



2.3 Captive Power Plant:

2.3.1 Introduction:

National Fertilizers Limited has set a Captive Power Plant (CPP) at their complex at BATHINDA,

to ensure availability of stable, uninterrupted power and stream to the Ammonia and Urea plant.

This will minimize the tripping of the Fertilizer Plant due to transit voltage dips and power

cuts.Since inception, Bathinda unit was drawing electric power from Punjab State Electricity

Board (P.S.E.B). Electricity is the main driving force after steam in the plant, being used for

moving auxiliary equipments.

The unit requires 27MW of power/hr when running at full load. There are two 15 MW turbo-

generators to generate power. Under normal running conditions of the plant and healthiness of the

P.S.E.B. grid, we generally run in synchronism with the grid merely drawing the power

corresponding to the minimum charges to be paid to state electricity board. In case of any

disturbance in the grid, our system gets isolated from the grid automatically.

With both generators running, we are able to feed power to the whole plant, thus production is not

affected. In case only one turbo generator is in line and grid cuts off, urea plant is cut off

automatically to balance the load with one generator. As soon as the grid becomes stable, the

generators are again synchronized with it.

The power generation of each generator can be varied with 2 MW to 15 MW maximum, provision

exists to run the generator on 10 % extra load continuously for one hour only. Operation of C.P.P.

is based upon microprocessor based computerized instrumentation which allows automatic

operation, start up, shut down of the whole or part of the plant.

Latest instrumentation has been used in this plant. It allows controlling process variables like

flow, pressure, temperature, power factor, voltage, frequency, etc.

There is operator interface unit (IOU) Like a TV screen on which various parameters can be

displayed and controlled. It allows fully automatic start-up, shut-down of boiler, turbine and other

auxiliaries.



2.3.2 Need for CPP:

It was thought to install a captive power plant in which electric power for our requirement shall be

generated in a COAL FIRED BOILER. The benefits envisaged were:

i) Any disturbance in the PSEB grid used to trip the whole plant. Lot of money was lost due to this

as each re-startup costs around 40 to 50 lakhs rupees. Moreover, frequent tripping‟s had an ill

effect on machines and equipments extending the re-startup period.

ii) Three boilers of 150Te/hr steam capacity were initially installed in SGP to keep 25 boilers

running and one stand by as designed steam requirement was less than 300Te/hr. but in actual

operation steam requirement was more and all three boilers had to be run and there was no

breathing time for their maintenance.

iii) As new boiler was to be installed for CPP, its capacity was so designed that it could export

around 60Te of steam for process requirement so that only boilers of SGP would be run keeping

the 3rd

as stand by.

With these points in mind CPP was installed. The functioning of CPP can be sub-divided into

parts:

2.3.4 Boiler Requriement:

For generation of high pressure superheated steam.

2.3.5 Boiler:

The basic principle of this boiler is the same as discussed earlier for SGP boiler that is formation of

steam by heating boiler feed water inside furnace fired by coal and heavy oil, utilization of heat of

the gases and venting these gases at a safe height. Main differences between the two boilers are:

SGP boiler is tangentially fired where as CPP boiler is front fired with 6 coal burners and 6 oil gun

fixed inside the coal housing. SGP boiler can be loaded up to 30% load with oil firing only

whereas CPP boiler can be fully loaded with oil alone. Height of combustible zone in CPP boiler is

more and it has residence time of 1.5 sec where SGP boiler has 1.0 sec.Mills used for

pulverizations of coal in SGP are negative pressure bowl mills whereas in CPP ball tube mill are

used which are positive pressure mills. Due to more residence time and better pulverization the

efficiency of CPP boiler is about 4% higher. Boiler feed water required for steam generation can

be fully generated in CPP itself. A part of the steam generated is exported for process use in

ammonia plant and rest is utilized for power generation in turbo generators as described below:



Fig 2.4 Water tube Boiler

2.3.6 Descripton of the boiler:

Mitsuy Relay Type Boiler

Maximum evaporation 2, 30,000kg/hr

Design process for boiler 124 kg/cm2G

Steam temp at outlet 4950C

Heating surface 1250M2

2.3.7 Turbo-Generator Requirement:

To generate power, using steam from the boiler.Operation of CPP is based upon microprocessor

based computerized instrumentation which allows automatic operation, start up, shut down of the

whole or the part of the plant.

2.3.8 Power Generation:

In C.P.P., two generators of 15MW capacity generate a voltage of 11KV, which is fed to the two

transformers in the yard. The rating of the transformers is 31.5/25 KVA, these two values depend

upon the cooling which we provide, as here 25KVA capacity is when cooling is oil natural air

natural and 31.5KVA capacity is when cooling is oil natural air forced. Both these transformers



step up the voltage level to 132KV. From the transformers the three phases pass through the

lightning arrestors (LA). After this, they pass on to the isolator. After this the two lines pass on to

the TRANSMISSION pole called DOUBLE CIRCUIT TRANSMISSION. Then these lines go to

the M.R.S. i.e. main receiving station.

2.3.9 Turbine:

M/S SGP of AUSTRIA supplies the turbine used. It is condensing cum extraction turbine designed

as single casing reaction turbine with single control stage and high pressure (HP), mild pressure

(MP) and low-pressure (LP) reaction parts.

The turbine is fed with high-pressure steam at 100kg from boiler and flows through various control

valves for normal and emergency operation. It gets high velocity through the nozzle group and

then passes over the impellers fixed on to the rotor and fixed diffusers thus rotating the turbine.

The enthalpy of steam is utilized in steps. Steam is also extracted from various stages. HP1 at

10.4kg/cm2, HP2 at 8.1kg/cm

2, feed water bleed at 4.3kg/cm

2 and LP bleed at 0.9kg/cm

2.The

exhaust steam from the turbine is condensed in a condenser maintained under vacuum to extract

maximum steam enthalpy.

The output of the turbine depends on flow of steam and heat difference that is on condition of

steam at the main steam valve and the pressure at the turbine outlet or condenser pressure. The

turbine is connected to the generator through speed reducing gears.The exhaust steam is condensed

in a condenser using cooling water.

Fig 2.5. Shows General concept of power generation by

Steam turbine



The resulting condensate can be fed back to LP heater but is normally sent to the polishing water

plant. As shall be clear from the attached block diagram various bleeds from the turbine are

utilized for heating purpose. HP1 and HP2 are used for heating boiler feed water in HP1 and HP2

heaters. Feed water bleeds is used for heating the feed water tank and LP bleed is used for heating

the polish water make up to the feed water tank.

A lubrication system is also there to lubricate the various bearings of the turbine, gears and

generator. Normally the oil pump driven by the turbine shaft supplies oil but auxiliary motor

driven pumps are used for start up and during shutdown.

A turning gear has been provided for slow cooling of turbine rotor. Latest instrumentation has been

used in this plant. Bailey‟s net work-90 microprocessor based instrumentation system is being

used.

The NETWORK 90 SYSTEM is a distributed process control system. Using a series of integrated

control nodes.

The network 90 system allows controlling process variables like flow, pressure and temperature

according to a control configuration.

There is operator interface unit (OIU) like a TV screen on which various parameters can be

displayed and controlled. It allows fully automatic start-up/shut-down of boiler, turbine and other

auxiliaries.

2.3.10 Description of Turbine:-

A simple tabular data shows the description and configurations of turbine currently operated in the

plant:

Table2.3 Showing configurationof turbine

Make Simmering Graz Panker, Austria

Type Multifunction (28 stages)

Capacity 65 T/H at 15 MW

RPM 6789 at 50 Hz

Critical speed 3200-3600 RPM



2.3.11 Genrator:

CPP is having two number turbo generators of capacity 15MW each. The generators are type SAT

three phase, 50Hz, 11kV, 984amps, at 0.8 power factor rating supplied by M/S JEUMONT

SCHNEIDER OF FRANCE. These are totally enclosed self ventilated type with two lateral airs to

water coolers for cooling. The alternators are able to bear 10% overload for one hr with an increase

in temp. of 100C while maintaining the voltage as near as possible to the rated one. The excitation

is compound and brush less with exciter rotor and Rectifier Bridge mounted on the extended main

shaft on non driving end. The excitation is controlled automatically with automatic voltage

regulator and a PLC controller. All protection relays installed for protection of generator are solid

state having high accuracy, quick response and low power consumption. Under normal running

conditions of the plant and healthiness of the PSEB grid, we generally run in synchronism with the

grid merely drawing the power corresponding to minimum charges to be paid to state electricity

board. In case of any disturbance in the grid measured by higher low frequency, high rate of

change of frequency, low voltage etc. our system gets isolated from the grid automatically. With

both generators running, we are able to feed power to the whole plant, thus production is not

affected.

2.3.12 Uninterrupted Power Supply: -

The uninterruptible power supply system is connected between a critical load, such as digital

drives & automation, distributed digital process control system, telecom equipment, programmable

logic controller, mission critical applications, computer and its three phase mains power supply

under all rated load and input supply conditions.

The system offers the user with the following advantages: -

i) Increased power supply: -

ii) The UPS has its own internal voltage and frequency regulator circuits which ensure that its

output is maintained within close tolerances independent of voltage and frequency variations on

the mains power lines.



2.4 Steam Generation Plant

Steam Generation plant is mainly installed for production of steam and then distributed to various

parts of the plant. Here this section of plant installed in National Fertilizers Limited, Bathinda unit

produces and supplies steam at 100 Kg / cm2

pressure and nearly 480°C temperature to Ammonia

Plant.In today‟s world steam has gained importance in Industries. It may be used for power

processes and heating purposes as well.

2.4.1 Benefits of Steam:

i) It is colorless, odourless and tasteless.

ii) Very economical

iii) Non-polluting

iv) Can be used as heat exchanger.

v) It can be easily distributed to various sections of plant.

2.4.2 Steam generation in Plant:

Steam is generated in Boilers (Water tube boilers mounted on common base fitted with mountings

and fittings) and then distributed to other parts of plants. For governing the quantity of fuel to be

burned and for maintaining the required pressure their are many automatic fuel feeders,

equipments and auxiliaries like pressure gauge etc.

In the Boilers used at National Fertilizers Limited (Bathinda unit); coal, oil natural gas are used as

a fuel for production of steam.

NFL , Bathinda is using steam for two purposes ; first and the main reason is for running prime

mover and other reason is to exchange heat in the processes taking place their.

There are three boilers capable of producing steam at the rate of 150 Tonnes/hr installed in CPP

which were supplied and erected by BHEL.

Generally two boilers are enough to meet the requirements but third boiler is simultaneously

running because if steam load consumption increases then the third boiler plays its part in order to

avoid any faulty condition.



2.4.3 Fuel Used:

There are presently two fuel are used for the steam generation:

i) Coal :

To obtain steam of desired Temperature and pressure, coal is burned to give major source of

heat.Initially coal is stored at Coal Handling plant brought from coal sites.

It is this section of plant where coal is crushed by crushers in order to make small pieces of coal,

then after crushing it the coal pieces rare passed through heavy electromagnet where iron is

separated from coal if present.

Coal is then sent to Bunkers from where it goes to Grinding mill. Grinding mill is grinding coal

into powder form.Conveyor Belts are being used in the whole plant for transportation of Coal.

The powder form of coal is sent to the Boilers through pump as pump sucks the coal from grinding

mills and throws it into the boiler for combustion.

ii) Oil :

As the Boilers are designed to work on both Coal as well as Fuel Oil so fuel oil can also be

pumped to Boiler for combustion.

Generally coal alone is not burnt Initially but Fuel Oil (LSHS) is mixed coal and then sent to the

furnace for combustion in order to get desired temperature .

2.4.4 Steam Requirement at Plant:

As National Fertilizers Ltd, Bathinda unit has its own Steam Generation Plant where steam is

produced which is used for driving Turbo Compressors, Heating Purposes, for various reactions

taking place in the plant itself.

Steam is mainly consumed in the Ammonia Plant as nearly 6 to 7 tonne of steam is required to

produce 1 tonne of Ammonia. High Pressure Turbines are being used where high pressure and

temperature is to be maintained so SGP section plays a important role for maintaining the said

condition. There are three boilers (VU-40 type supplied by M/S BHEL) of 150 tonne/hr capacity

.These boilers are Water Tube Boilers i.e. water is inside the tubes and hot air surrounds it when

coal is burnt, this makes the water in the tubes boil and steam formation takes place. In the

beginning coal is burnt with fuel oil in order to get desired temperature.



2.4.5 Water and Steam System:

As the steam being used should be free from impurities like minerals, silica, oxygen, Iron etc. in

order to insure Safe and Efficient working of Steam turbines and Boilers. For this purpose Raw

Water is physically and chemically treated and finally supplied to Steam Generation Plant from

Ammonia plant. This water is called Boiler Feed water which is further heated to 240º C by the

flue Gases and taken to Steam Drum. Steam Drum Acts as storage tank and also separates water

from the steam at 315º C and 106 kg/cm2 pressure water then enters the Ring Header formed at on

the bottom of outside the furnace and rises by gravity through water wall tubes on the all the four

sides, taken heat from furnace and enters steam drum as a mixture of steam and water.

2.4.6 Flue Gas System:

The products of combustion in the furnace consist of carbon-di-oxide, nitrogen, ash, oxygen and

sulphur-di-oxide. After leaving the furnace the heat

Of these gases called FLUE GASES, is utilized at various levels.

First the steam from steam drum is heated in two super heaters to get the required temperatures of

4950C and then feed water in BANK TUBES is also heated and the gases leave bank tubes at

around 4970C next the heat is utilized to heat feed water in the ECONOMIZER and gases are

cooled down to 3200C. These gases are further cooled down to 150

0C in ROTARY AIR HEATER

where the air is required for combustion and conveying the coal is heated up. Temperature is not

reduced further because at lower temperature oxides of sulphur present in flue gases are converted

to ACID which damages the down stream equipments. These gases then pass through ELECTRO

STATIC PRECIPITATOR (ESP) where ash is removed.



2.5 Offsites and Utilies (O&U):

The O & U group of plants consist of the following sections : -

i) Raw Water Plant.

ii) D.M. Water Plant.

iii) Instrument .Air Compressor House.

iv) Cooling Tower.

i) Raw Water Filtering Plant:

This water treatment plant has a design capacity to treat 2400 NM3/hr of raw water into portable

occasional over lead of 20%. The plant consists essentially of flash Mixers Clarifloculators, rapid

gravity filters and a chemical House comprising of Alum tanks, lime tanks and a chlorine room

etc.The raw water from the pumping main is received by the inlet of the RCC Ventury flume. In

the ventury flume the calculated amount of alum solution is closed for mixing with the raw water.

The chemically treated water then flows to clarifloculators. The pludge thus formed after chemical

treatment settles down in the clarifloculator where from it is expelled out while the clear water

overflows to the launder leading to filter beds. The filter water is disinfected with the addition of

chlorine and then collected in filter eater sump.

ii) D.M. Water Plant

D.M. water plant was supplied by M/s Ion Exchange (India) Ltd. It consists of cation units,

Degasser Towers, An-ion units. Mixed bed units No.l&2. Filtered water coming from raw water

filtration plant is received in filter water reservoir. From reservoir filter water passes through a

strongly acidic cat-ion exchange resin where cat-ions like Ca, Ng & Na are removed, the water

passes through degasser tower where dissolved, Ce2 is removed.

Then water passes through Anion exchange resin and Anion like CI, S, Se4 and silica, are removed

in this unit. Free from cations and anions water passes through mixed bed unit No.l, where further

removal of cations and anions takes place. Then treated water coming out from MB, unit goes to

DM water tank.Return condensate from Ammonia and Urea Plants is collected in D.M. water tank

after treatment in cat-ion unit No.2. Then D.M. water is pumped from DM water tank to mixed bed

No.2(MB) for further polishing and collected in polish water tank, which is supplied to boilers

through Ammonia Plant.



iii) Instrument Compressor House:

The purpose of this section is to supply instrument air and service air to all the plants. The

instrument air compressor house consists of three instrument air compressors and one service air

compressor. One is kept in line generally. The compressed air from instrument air compressors at

9.3 kg/cm2 absolute pressure passes through two sets of dryer, which is filled with silica-gel for

removal of moisture. Air coming out from dryer is sent to instrument air feeder for supplying to

different plants through instrument air receiver in order to drive various valves and instruments.

iv) Cooling Towers:

The cooling water system provided in NFL, Bathinda is closed re-circulating system supplying

cooling water to various consumers in the plant. The system mainly consists of cooling towers,

cooling water re-circulation pumps, supply & return headers and cooling water treatment facility.

There are three cooling water systems : -

i) C.W. system supplies cooling water to Ammonia Plant.

ii)Urea Plant and Boilers, Instrument -Air Compressor, Caustic dissolving facilities & Sulphur

recovery Plant.

Iii) C.W. system supplies cooling water to Crystallization section of Urea Plant.

Fig. 2.6 Cooling Tower



2.6 Pumps:

Mechanical equipments used to propel liquid under pressure from one location to another through

piping. It basically increases the liquid pressure as the liquid circulates through the pump.

2.6.1 Types of pumps :

There are basically three types of pumps namely:

i) Centrifugal Pump

ii) Reciprocating Pump

iii) Rotary Pump

i) Rotary Pumps:

Rotary pumps are used for moving extremely heavy or viscous commodities such as grease,

asphalt, heavy fuel oils and sometimes heavy crude oils. There are three main types of rotary

pumps: gears, cams and screw

Fig.2.7 Rotary Pump



ii) Centrifugal Pumps:

These create centrifugal force which creates rise in pressure to move the liquid by forcing it into a

rotating impeller and literally throwing it out the discharge nozzle, producing a smooth, non-

pulsating flow in the piping system.

Problem with centrifugal pumps is CAVITATION.

When the liquid passes from the pump section to the eye of the impeller, the velocity increases and

pressure decreases. There are also pressure losses due to shock and turbulence as the liquid strikes

the impeller. The centrifugal force of the impeller vanes further increases the velocity and

decreases the pressure of the liquid. The vaporization occurs when this pressure drops to

atmospheric pressure. The vapor pressure occurs right at the impeller inlet where a sharp pressure

drop occurs. The impeller rapidly builds up the pressure which collapses vapors bubbles causes

cavitation and damage the pump internals. This is avoided by maintaining NPSH (net positive

suction head).

Fig. 2.8 Centrifugal Pump



ii) Reciprocating Pump

Reciprocating pump has plungers that go back and forth like a car‟s pistons to displace liquid,

forcing it violently out of the discharge nozzle. They operate at much lower rpm and each

plunger‟s thrust causes pulsation in suction and discharge piping. The pump is taking in liquids at

the same rate at which it is discharging liquid, and by the same reciprocating action, thereby

causing the suction line to pulsate too. This pulsating action causes the pipe to pulsate too and

thereby if not held down, it will eventually fatigue.

Fig.2.9 Reciprocating Pump

2.5.3 Pump Maintenance:

Effective problem identification and problem avoidance requires a rigorous investigation process.

When a pump failure occurs, it is very tempting to remove the pump, replace the defective parts

(or the entire pump), install the new or rebuilt unit, and get the unit back on line as quickly as

possible. However if several checks are not made during the removal and disassembly process,

important clues as to the cause of the problem will be overlooked. Below is a recommended

checklist that should be done when any pump is removed from service to assist in identifying the

source of the failure. In fact, it may not be a bad idea to perform many of these checks on an

annual basis.



2.7 Compressor:

Compressors, in simple words, can be described as a mechanical devices used to increase the

pressure of air or gas. Compressors provide sufficient pressure for gases and vapors. In most

piping installations, compressors are used primarily for the creation of highly pressurized air for

different parts of the plant, such as utility air, pneumatic valves. Compressors can develop pressure

as high as 20,000 psig.

There is a wide range of compressors ranging from reciprocating to rotary. Filters, separators,

receivers, silencers and coolers are pieces of equipment that make up a whole compressor unit. The

compressor units are elevated above the grade level and are provided with an enclosed are to keep

the unit dry.

Two major problems associated with compressor units are :

unwanted foreign material in the system and liquid retention. Both can cause serious damage to

the unit.

Sufficient room around the compressor unit must be provided for maintenance and operation,

including access to valving and piping.

2.7.1 Types of Compressors

i) Centrifugal Compressor :

Centrifugal compression is a force converted to pressure when a gas is ejected by an impeller at

increasing velocity. These are specified for large quantities of vapors. Pressure diffential may be

small or large. There are two basic types of centrifugal compressors. VERTICALLY SPLIT case

types are used for high pressures; HORIZONTALLY SPLIT case type for low to moderately high

pressures. Centrifugal compressors may have upto ten stages of compression within one casing. If

more than ten stages are needed two or more compressors can be coupled together and powered by

a common driver. This is called tandem drive.



ii) Reciprocating Compressor:

These are generally specified for lower volumes than centrifugal compressors. With several stages

of compression, extremely high pressures may be developed. Because of their reciprocating action,

these machines cause piping to pulsate, to vibrate and generally to fatigue if it is not properly

designed.

Fig.2.10 Reciprocating Compressor



iii) Aial Flow Compressor:

Axial compressors consist of rotating and stationary components. A shaft drives a central drum,

retained by bearings, which has a number of annular airfoil rows attached usually in pairs, one

rotating and one stationary attached to a stationary tubular casing. A pair of rotating and stationary

airfoils is called a stage. The rotating airfoils, also known as blades or rotors, accelerate the fluid.

The stationary airfoils, also known as stators or vanes, convert the increased rotational kinetic

energy into static pressure through diffusion and redirect the flow direction of the fluid, preparing

it for the rotor blades of the next stage.The cross-sectional area between rotor drum and casing is

reduced in the flow direction to maintain an optimum Mach number using variable geometry as the

fluid is compressed.

Fig. 2.11 Axial Flow compressor



2.8 Maintenance:

2.8.1 Maintenance Objective:

1. To achieve minimum breakdown and to keep the plant in good working condition at lowest

possible cost.

2. Machines and other facilities should be kept in such a condition which permits them to be used

at their optimum capacity without any interruption or hindrance.

3. Availability of the machines, building and services required by other sections of the factory for

the performance of their functions at optimum return on investment be in material, machinery or

personnel.

2.8.2 Responsibilities of Maintenance Engineer:

i) Inspection:

Its concerned with the routine schedule checks of the plant facilities to examine their condition

and to check for needed repairs. Frequency of inspections depends upon the intensity of the use of

the equipment. Inspection section makes certain that every working equipment receives proper

attention.

ii) Engineering:

It involves alterations an improvements in existing equipments to minimize breakdowns. It also

includes inventorying outside technical assistance.

iii) Repair:

It includes carrying out corrective repairs to alleviate unsatisfactory conditions. Such a repair is

usually of emergency nature.

iv) Overhaul:

It includes planned , scheduled reconditioning of plant facilities such as machinery etc. It also

involves replacement, reconditioning, reassembly, etc.



2.8.3 Actions Performed by Maintenance Department

i) Condition monitoring

ii) Spare procurement

iii) Inventory control

iv) Import substitution

v) Development of manpower

vi) Analysis of history such action should be taken of behavior of the machine and its

vii) Replacement of worn out component .

viii) Repair of cracks or restore the original operational other repairable capacity of the machine

damages and prevent further damage.

ix) Modification of design affect improvements to reduce the frequency of attention or location of

the reduced cost of maintaining equipment.

x) Capital replacement of the machine when the age of the existing machine requirements of

quality and quantity of output and emergence of better machines make it economical to dislodge

the present and install a new machine.

2.8.4 Maintenance Priorities:

Emergency: Necessary to stop serious loss or violation, automatic approval, start within 24

hr., schedule or unscheduled.

Urgent: Necessary to ensure production reliability and/or prevent quality loss, approval

required, schedule for specific date within 3 days.

Normal: Necessary to improve quantity or quality of product and/or increase production

reliability, approval required, scheduled, starts within 7 days.

Future: Work not covered by others priorities, approval required, scheduled, starts within 30

days.

Shutdown: Work that can be postponed or can be completed when a unit is shut down,

approval required, scheduled during shutdown. Unscheduled equipment breakdowns, requiring

corrective maintenance, occur in all plants an usually warrant an “emergency” or “urgent”

priority.



Chapter 3

Project Review

3.1 Objective:

To study the process of steam generation in Steam Plant and Captive Power Plant.

3.2 Review:

In Steam Generation Plant we study the various phases through which steam is generated to

produce electricity for NFL Plant. We study these under the guidance of Mr. Rajesh Maurya

(Deputy Manager) and Mr. Devinder Kumar (S.O. SG) who clear the path to understand the whole

production system. The study of these plant includes:

Study of Turbine, Nozzle, Generators

Study of H.P heater, L.P heater and Feed water Control station

Study of Boilers

3.3 Observations deduced:

This project includes various observation deduced as a spectator in the industry.Some of the main

observation deduced are:

Minimum and maximum temperature requirement for plant working

Minimum and maximum pressure conditions that can bear out by the plant.

Boiler , L.P heater, H.P heaters and Feed water control Station brief working conditions with

precaution to be taken during emergency conditions.

In the end we express our sincere thanks to most co-operative staff members because of this

project study became successful.



Chapter 4

Project work

4.1 Study of Turbine, Nozzle, Condenser and Turbo-Generator:

Here is the description of the Turbines , nozzle and generator which are currently operated in

NFL, Bathinda unit.

4.1.1 Study of Turbine & Nozzle:

Simply speaking, a turbine is like a windmill. A turbine, however, is much more complex with

hundreds of rotating blades, called buckets, and stationary nozzles. The blades are arranged in

groups, which are also known as stages. Steam enters the first stage, then passes from stage to

stage, giving up energy and thus drops in pressure as the steam moves through the stages. This

movement causes the rotor to turn.

Unlike the simple diagram you just saw, a turbine has multiple nozzles and blades that have curved

entrances and exits. These blades are also known as buckets. The graphic on the left is a detailed

drawing of the nozzle partition and buckets, and the graphic on the right is a cross-section of a

turbine showing how they are arranged on the shaft.

In an actual turbine, the steam flow begins when the high-pressure steam leaving the boiler enters

the turbine at speeds over 1000 miles per hour and temperatures of approximately 1000 degrees

Fahrenheit. This high-temperature, high-pressure steam enters through the inlet control valves,

which control the steam flow into the turbine. The steam then travels through the first-stage

nozzles, and strikes the first row of buckets.

Fig 4.1 Steam passing through turbine



At this point the pressure is decreasing as the steam is redirected through the nozzles. The

expanding steam continues to flow through the rows of nozzles and buckets, each time striking the

buckets which causes the main shaft to rotate and produce power. By the time the steam is ready to

leave the turbine, almost all of its usable energy has been removed. The pressure drops from inlet

to exhaust can range from 300 PSI to over 3000 PSI and can vary considerably dependent upon the

turbine and boiler design.

Fig 4.2 Shows steam processed through Turbine to boiler.

Fig 4.3 shows 3D view of nozzle partitions and buckets placing



4.1.2 Study of Condenser:

The condenser is where the steam leaving the turbine (also known as the exhaust steam) is

condensed by cooling water. The condenser is basically a box made of heavy steel that is attached

to the exhaust opening of the turbine. It contains a bank of small tubes through which cold water

flows. Therefore the steam leaving the turbine exhaust enters the condenser where it

comes in contact with these cold tubes and is returned to its liquid state.

The condensing of the steam creates a vacuum that reduces the atmospheric back pressure. In a

turbine, vacuum is measured in inches of mercury (Hg), with 29.92 inches of mercury being a

perfect vacuum. This is more efficient because without a vacuum the exhaust steam encounters

resistance from the atmosphere and thus requires more work. By removing this resistance the

turbine has more power and the flow of the steam is no longer impeded. The condensed steam

collects in the hot well, which is a reservoir at the bottom of the condenser, and is pumped back to

the boiler where the cycle begins again.

Fig. 4.4 Sectional view of condenser



4.1.3 Study of Turbo-Generator:

There are two generators of 15MW at NFL, Bathinda unit. A turbo generator is the combination of

a turbine directly connected to an electric generator for the generation of electric power. Large

steam-powered turbo generators provide the majority of the electricity.

For base loads diesel generators are usually preferred, since they offer better fuel efficiency,

but on the other hand diesel generators have a lower power density and hence, require more

space.

The efficiency of larger gas turbine plants can be enhanced by using a combined cycle, where

the hot exhaust gases are used to generate steam which drives another turbo generator.

Table 4.1 TG operating parameters before and after Overhauling

Sr.No. Parameters Date (Before O/H) (After O/H)

1 Turbine Load MW 8.0 8.0

2 Steam Consm. Te/Hr 42 37.0

3 Steam Cons. Te/MWh 5.25 4.63

4 W.C.Press. Kg/Cm2 24.8 28.36

Temp. Deg.C 404 405

5 HP-2 press Kg/Cm2 11.6 10.9

Temp. Deg.C 345 339

6 HP-1 press. Kg/Cm2 NA NA

Temp Deg.C NA NA

7 LP bleed Pr./ Kg/Cm2 0.11 -0.03

Temp. Deg.C *281 (not

correct)

212

8 FWT bleed Pr. Kg/Cm2 3.95 3.1

Temp Deg.C 271 261.8

9 Exhaust Press. Kg/Cm2 -0.91 -0.94

Temp. Deg.C 47 41.36

10 Axial thrust MM 0.15/0.13 0.17/0.18



4.2 Study of Feed water heaters and Feed water Control station:

This section includes the whole feed water system comprising of feed water heater and feed water

control station.

4.2.1 Feed water heaters:

A feed water heater is a power plant component used to pre-heat water delivered to

a steam generating boiler. Preheating the feed water reduces the irreversibilities involved in steam

generation and therefore improves the thermodynamic efficiency of the system. This reduces plant

operating costs and also helps to avoid thermal shock to the boiler metal when the feed water is

introduced back into the steam cycle. In a steam power plant feed water heaters allow the feed

water to be brought up to the saturation temperature very gradually. This minimizes the inevitable

irreversibilities associated with heat transfer to the working fluid (water). Closed feed water

heaters are typically shell and tube heat exchangers where the feed water passes throughout the

tubes and is heated by turbine extraction steam. These do not require separate pumps before and

after the heater to boost the feed water to the pressure of the extracted steam as with an open

heater. However, the extracted steam must then be throttled to the condenser pressure, an

isenthalpic process that results in some entropy gain with a slight penalty on overall cycle

efficiency. Basically, two types of Feed water heater are used at NFL Bathinda are H.P heater and

L.P heater.

Fig 4.5Feed water heater

https://en.wikipedia.org/wiki/Power_plant

https://en.wikipedia.org/wiki/Steam

https://en.wikipedia.org/wiki/Boiler

https://en.wikipedia.org/wiki/Thermodynamic_efficiency

https://en.wikipedia.org/wiki/Thermal_shock



4.2.2 Feed water control Station:

All the feed water heater processing is monitored and controlled by the Feed water control station.

Water-level controls continuously monitor the level of water in a steam boiler in order to control

the flow of feed water into the boiler and to protect against a low water condition which may

expose the heating surfaces with consequent damage.. The probes will be fitted in pads or

standpipes on the crown of the shell or drum and enclosed in a protection tube which will extend to

below the lowest water level. With water tube boilers the control of the water level needs to be

precise and sensitive to fluctuating loads due to the high evaporative rates and relatively small

steam drums and small water content.

Three element control using the followings is applied during the normal operation :

Drum level

Main steam flow

Feed water flow

In order to handle the situation, the steam flow rate should also be considered for drum level

control. It can be done by adding the steam flow rate as a feed forward signal to the output of the

level controller. Hence, the supply of the feed water flow is compensated for changes in the steam

flow rate demand. With this strategy as the steam flow rate changes the demand for the feed water

flow rate also changes in the right direction and minimizes the effect of shrink and swell on the

drum level.

Fig 4.6 feed water control station layout



4.3 Boiler:

The NFL, Bathinda Plant uses water tube boiler for steam generation.

Steam generation steps in boiler:

i) The steam flow in the boiler begins when water enters thedrum from the economizer then travels

to the furnace where it is heated.

ii) A water-steam mixture is generated in the furnace water wall tubes and returns to the drum

through a series of headers and connecting pipes.

iii) Steam leaving the steam drum then passes through a bank of tubes known as the superheater

where the steam is heated further.

iv) The steam is then sent to the high-pressure turbine section.

Fig. 4.7 sectional view of boiler

4.3.1 Boiler Auxiliaries:

There are five main boiler auxiliaries:

i) Superheater

ii) Air preheater

iii) Reheater

iv) Economizer



i) Superheater:

A superheater is a device used to convert saturated steam or wet steam into dry steam used in

steam engines or in processes, such as steam reforming. There are three types of superheaters

namely: radiant, convection, and separately fired. A superheater can vary in size from a few tens of

feet to several hundred feet (a few metres to some hundred metres).

ii) Air-Preheater:

An air preheater (APH) is a general term used to describe any device designed to heat air before

another process with the primary objective of increasing the thermal efficiency of the process.

They may be used alone or to replace a recuperative heat system or to replace a steam coil.

iii) Reheater:

They are the same as the super-heaters but as their exit temperature is a little bite less than super-

heaters and their pressure is 20%-25% less than the super-heater, they can stand less quality

material alloys.

iv) Economizer:

An economizer serves a similar purpose to a feedwater heater, but is technically different. Instead

of using actual cycle steam for heating, it uses the lowest-temperature flue gas from the furnace

(and therefore does not apply to nuclear plants) to heat the water before it enters the boiler proper.

This allows for the heat transfer between the furnace and the feedwater to occur across a smaller

average temperature gradient (for the steam generator as a whole). System efficiency is therefore

further increased when viewed with respect to actual energy content of the fuel.

Fig. 4.8 Economizer



Chapter 5

Results and Discussions

5.1 Observations:

During the study of Captive Power Plant and Steam Generation Plant under which the various

operating components are bounded to be kept in the maximum and minimum range so as the plant

should work under optimum conditions. Here is the list of observation found during the working

condition of plant are as follows: Table 5.1 Boiler operation requirements

Sr. no. Operations Observations

1 Evaporation capacity 230 T/hr

2 Design Pressure Drum 124 Kg/cm2

3 Operating Pressure Drum 115.5 Kg/cm2

4 Superheater system pressure drop 10.5 Kg/cm2

5 Operating Pressure Superheater 105 Kg/cm2

6 Economizer Pressure drop 3.2 Kg/cm2

Table 5.2 Temperature of steam/water

Sr. no. Operation Observations

1 Drum operation 322oC

2 Entering low temperature superheater 322oC

3 Leaving low temperature superheater 383oC

4 Entering L.T.H.S after de-superheating 347oC

5 Leaving L.T.H.S temperature 435oC

6 Entering high temperature superheater 414oC

C Leaving high temperature superheater 495oC

8 Entering economizer water 200oC

9 Leaving economizer 259oC

Table 5.3Spray water quantity

Sr. no. Operation Observations

1 First spray water quantity between L.T.H.S & I.T.H.S 14.5 Ton/hr

2 Second spray water quantity between I.T.H.S & H.T.H.S 6.60 Ton/hr



5.2 Layout of Captive Power Plant and Steam Generation Plant

Fig. 5.1 Layout of Captive Power Plant and Steam Generation Plant



Chapter 6

Cautions during Problems

This chapter includes the measure and list of procedure to be followed to prevent accident and

component losses. Here is the list of five main and common problems may occur during the

general working of the plant.The set of procedure for :

6.1 High Condenser Level:

i) Decrease the TG Load

ii) Open the SV-118/218 (conform its opening from local.)

iii) Open the local drain.

iv) Open Bypass of CV-100/200.

v) Check for malfunctioning of either CV-100/200 DM side outlet valve .

vi) Or it may be maintained by openning recirculation valve at 4.5M.(in case CV 100/200 is open).

vii) 2ND

Condensate pump may be started.

6.2 Polish water failed from DM plant:

i) Open condenste re-circulation valve (4.5M) to LP OF TG-1,TG-2.

ii) Close main condensate valve (Common).

iii) Maintain the FWT level either by regulating BFW pump.

iv) Flow or throttling condensate outlet valve.

6.3 TG Vibration High:

i) Check for Gland Steam low temperature.

ii) Open Gland Steam Drain.

iii) TG load may be reduced.

iv) Check lubricating oil temperature.



6.4 Steam Temperature is low:

i) Decrease TG load

ii) Bypass low temperature and watchout for trip.(TG vibrations)

iii) In case of abnormal vibrations trip TG.

6.5 Exhaust temperature High/Vacuum low:

i) Open condenser re-circulation of CV-101/201 & make up for quenching.

ii) Check cooling water flow temperature.

iii) Decrease the TG load as the situation demands.



Chapter 7

Conclusion

The introduction of the system of a job training in industries added new dimension to the technical

education in the state of Punjab . Such a practical training not only focuses visions of the students

but also helps us to encounter heavy machinery and study its working . This goes a long way to

understand the engineering theory more vividly and grasp it easily. Efforts have been made to

study National Fertilizers Limited, Bathinda Unit. in systematic and proper way under the valuable

guidance of Mr. Rajesh Maurya(DM) and expressed this in the report little bit I have understood.

Working in an industry is quite different from college study. There is no prescribed book or

syllabus and whatever is to be learnt has to be from hands on experience on the job. I feel that

objectives of training are fully achieved and I have learnt a lot about functioning of an industry.



BIBILIOGRAPHY:

1. Official Website of NATIONAL FERTILIZERS LIMITED – www.nationalfertilizers.com

2. Official Websites of the TOYO Engineering which Started up NFL plant- www.toyoindia.com

3. Official Website of the HALDOR TOPSOE India Pvt. Ltd.– www.topsoe.com

4. My Mentor at NFL plant Mr. Rajesh Maurya & Mr. Kulwant Singh

nfl bathinda training file

Documents

urea plant

ammonia plant

steam generation plant

layout of captive power

successful industrial

month industrial training

bathinda rahul chadha

rahul chadha roll