nfl-bathinda final.docx

8/10/2019 NFL-Bathinda Final.docx

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INTRODUCTION

NFL Schedule - A & Mini Ratna Category 2004-2005. - ICompany, is a market leader in the fertilizer Industry in India

With 17.0% share in Urea production during 2004-2005.

PERCENTAGE SHARE OF NFL IN

UREA PRODUCTION

IN THE COUNTRY (2004-2005)


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NFL was incorporated on 23rd August,

1974 with two manufacturing Units at

Bathinda and Panipat. Subsequently, on

the reorganization of Fertilizer group o

Companies in 1978, the Nangal Unit o

Fertilizer Corporation of India came under

the NFL fold. The Company expanded its

installed capacity in 1984 by installing and

commissioning of its Vijaipur gas based

Plant in Madhya Pradesh.

NFL Corporate office: Noida

The Vijaipur Plant was a land mark achievement in project management in India.

The plant was completed well within time and approved project cost. In recognition of

this achievement, the project was awarded the First Prize in Excellence in Project

Management by Govt. of India. Subsequently the Vijaipur plant doubled its capacity to

14.52 lakh MTs by commissioning Vijaipur Expansion Unit i.e. Vijaipur-II in 1997. The

plant annual capacities have now been re-rated w.e.f. 1.4.2000 from 7.26 lakh MT of

Urea to 8.64 lakh MT for Vijaipur-I & Vijaipur-II Plants each.

Three of the Units are strategically located in the high consumption areas of Punjab and

Haryana. The Company has an installed capacity of 35.49 lakh MTs of Nitrogenous

Fertilizers and has recorded an annual sales turnover of Rs.3,474 crores during 2004-05.

The Companys strength lies in its sizeable presence, professional marketing and strong

distribution network nationwide.

NFL, a profitable public sector undertaking operates under the administrative control

of Deptt. of Fertilizers in the Ministry of Chemicals & Fertilizers.

Kisan Urea and Kisan Khad NFLs popular brands are sold over a large marketing

territory spanning the length and breadth of the country. The Company also
http://www.nationalfertilizers.com/urea.htmhttp://www.nationalfertilizers.com/urea.htmhttp://www.nationalfertilizers.com/khad.htmhttp://www.nationalfertilizers.com/khad.htmhttp://www.nationalfertilizers.com/khad.htmhttp://www.nationalfertilizers.com/urea.htm


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manufactures and markets Biofertilizers and a wide range of industrial products like

Methanol, Nitric Acid, Sulfur, Liquid Oxygen, Liquid Nitrogen etc. The Company has

developed Neem coated Urea which on demonstration has improved the crop yield by 4-

5%. The Company is focusing its thrust to widen the marketing operations of Neem

coated Urea.

NFL over the years has developed a team of dedicated professionals in the areas

of production, maintenance, project management, safety and environment control. These

professionals are sought after in the Industry both in India & abroad for their Specialized

Services.

NFL is known in the industry for its work culture; value added human resources,safety, environment, concern for ecology and its commitment to social upliftment. All

NFL plants have been certified for ISO-9002 for conforming to international quality

standards and International Environmental Standard i.e. ISO-14001. With the

certification of Corporate Office/Marketing operations under ISO-9001:2000, NFL has

become the first Fertilizer Company in the country to have its total business covered

under ISO-9001 Certification.

The System of marketing of Urea has undergone a change w.e.f. 1.4.2003 when

company has been allowed to market 25% of its produce outside ECA during Kharif

2003. This percentage of sale outside ECA was raised to 50% in Rabi 2003-04, The

same portion prevails for 2004-05 and Kharif 2005.

Need for NFL the National Fertilizers Limited (Public Undertaking) was thought to plan

two modern large capacity single steam nitrogenous fertilizers plant in order to meet the

increasing demands.

On 23 rd August 1974, NFL was formed and registered to set up two modern large

capacity Nitrogenous Fertilizers plants.


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NFL, Bathinda (Punjab)

NFL, Panipat (Haryana)

each with the capacity of 5-11 lakh tones /annum.

As to set up any plant there are some essential conditions that support the existence

and working of plants for years, so Bathinda was basically selected as one of the site of

Fuel based plant as per consumption point of view since Punjab is mainly agriculture

based state.

" Feed in " at Bathinda was achieved on 7 th Dec. 1984 and from this project

ammonia was successfully produced on 28 th May 1979 and urea on 2 nd June 1979.NFL

was incorporated on 23 rd August 1974 in order to implement this project contract wereentered into with M/s " TOYO ENGINEERING CORPORATION " a well known

Japanese Engg. Company and Engg. India Ltd (EIL), a public sector and Engg.

Organization .This contract becomes effective on September 26, 1974 with a guaranteed

Feed in on the Bathinda Fertilizers project to implement within 36 months from the

zero date.

Due to the power requirements and some other factors, later on it was planned to

set up its own power house known as Captive Power Plant (CPP) with 2 turbo generators

of 15 MW each.

National Fertilizers Limited (N.F.L.) is the largest manufacturer of nitrogenous

fertilizers in the Northern India. It is presently operating four large fertilizers plants, two

of which are located at Nangal and Bathinda in the Punjab State, one at Panipat in

Haryana and one at Guna in M.P. While plants at Nangal and Panipat are fuel-oil based,

and at Bathinda and Guna are gas-oil based. The overall installed capacity of NFL plants

is 10.42 lakh MT per annum.


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Strategically Located - Urea Plants

Leading Producer of Nitrogenous Fertilizers in the Country.

Capital Cost, Feed Stock & Plants Capacity

Plants Capital Cost(Rs.Crore)

Feed Stock Existing Capacity

MT/Year (Lakh MT/Yr.)

Ammonia Urea CAN Bio-Fert.

Nangal-I 91.26 Naptha 0.66 - 3.181 -

Nangal-II 299.19 F.Oil/LSHS 2.97 4.785** - -

Panipat 338.41 F.Oil/LSHS 2.97 5.115 - -

Bathinda 349.41 F.Oil/LSHS 2.97 5.115 - -

Vijaipur-I 516.00 Natural Gas 5.016* 8.646* - -

Vijaipur-II 1071.00 Natural Gas 5.016* 8.646* - -

Indore 1.42 Strains - - - 100

Total 2666.55 19.602 32.307 3.181 100


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PRODUCTS OF NFL

National Fertilizers is producing Kisan Urea, Kisan Khad and Ankur on

commercial scale. NFL is also marketing number of Industrial products produced as By-

Products during the formation of Kisan Urea, Kisan Khad and Ankur in its plant itself.

FERTILIZERS PRODUCTS

Kisan Urea:

Kisan Khad:

INDUSTRIAL PRODUCTS (BY PRODUCTS)

Nitric Acid (HNO3)

Anhydrous ammonia (NH3)

Ammonium Nitrate (NH4NO3)

Nitrogen (N2)

Carbon dioxide (CO2)

Sodium Nitrate

Oxygen (O2)

Carbon (C) from slurry

IMPLEMENTATION AND PROJECT COST OF NFL BATHINDAUNIT

As NFL, Bathinda unit was planned to complete in 36 months from the Zero date

26 Sep.1974, so contract for completing this task was given to the well known Japanese


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company Toyo Engineering corporation limited and Indian Consultancy Companies as

well.

The overall approval cost of Bathinda Unit was Rs. 240.47 Crores with a foreign

exchange component which was mainly from Japanese Yen.

REQUIREMENTS OF RAW MATERIAL / INPUTS

Fuel Gas 850 MT / Day

Coal 1680 MT / Day

Water 13 MGD

Power 28 MW

PROJECT s BENEFITS

Increased Food Output

Employment to nearly 800 persons

Both Central and State Government has been benefited by way of excise duties and otherlocal taxes on Raw materials and other products.

Scope for marketing by-products such as CO 2 , Nitrogen , Oxygen , Carbon etc.

NFL won many major awards related to Safety , Productivity , Pollution control , Longest

accident free period .

- An OHSAS-18001 certified unit .

- An ISO-9002 and ISO-14001 certified unit .


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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 / cm 2 pressure and nearly 480C temperature to Ammonia

Plant.

In todays world steam has gained importance in Industries. It may be used for power

processes and heating purposes as well.

BENEFITS OF STEAM

It is colourless, odourless and tasteless.

Very economical.

Non polluting.

Can be used as heat exchanger.

It can be easily distributed to various sections of plant.

Steam is generated in Boilers(Water tube boilers mounted on common base fittedwith 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 b BHEL. Generally two boilers are

enough to meet the requirements but third boiler is simultaneously running because if


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steam load consumption increases then the third boiler play its part in order to avoid any

faulty condition.

FUELS USED

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.

Fuel Gas : As the Boilers are designed to work on both Coal as well as Fuel Gas so fuel gas can also be p

Generally coal alone is not burnt Initially but Fuel Gas is mixed coal and then sent to the

furnace for combustion in order to get desired temperature .Flue gases produced whichare very hot surrounds the water tubes (Tubes carrying water).When hot flue gases

surrounds the water tubes, the temperature of water in tubes starts rising ,as a result

Steam is generated.

WHY AND WHERE STEAM IS REQUIRED

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 tonnes of steam is

required to produce 1 tonne of Ammonia. High Pressure Turbines are being used where


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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.

FIRING SYSTEM

As coal brought from various sites is in form of big pieces of various sizes , so first

it is reduced in smaller pieces known as pulverized coal which is then further grinded

using BOWL MILLS so that it burns completely in the furnace to give proper

combustion.

Coal received from material handling plant is stored in coal bunker and is fed to

bowl mill through a coal feeder .Hot air is also supplied in the mill for heating the coal

and conveying it to furnace through a fan called EXHAUSTER FAN which takes suction

from the mill and maintains it under negative pressure. Oversize and un grind able

material like stones are thrown out by the mill. Pulverized fuel i.e mixture of coal and air

is supplied to Coal Burner through Exhauster. Coal burners are arranged tangentially onall the four corners of the rectangular furnace at three elevation levels. Thus there are

total 12 Burners. In between these, three elevations Gas Burners and Start Up

Burners/Igniters are arranged at two elevations. Thus there are 8 Gas Burners and 8

Igniters.

Igniters use LPG .

The Furnace is a cubical suspended enclosure with water tubes forming its four

walls. The furnace is designed with sufficient volume to provide for complete and

efficient combustion at all loads without flame impingent by the reaction of carbon

present in coal and the oxygen present in the air to form Carbon-Di-Oxide.

C + O 2 CO 2 + Heat


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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 240 C by the flue Gases and taken to Steam Drum. Steam

Drum Acts as storage tank and also separates water from the steam at 315 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 .

FLUE GAS SYSTEM

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

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 495 0C and then feed water in BANK TUBES is also heated and the gasesleave bank tubes at around 497 0C next the heat is utilized to heat feed water in the

ECONOMIZER and gases are cooled down to 320 0C. 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. These gases then pass through ELECTRO STATIC

PRECIPITATOR (ESP) where ash is removed. From ESP these gases pass on to

INDUCED DRAFT FAN which maintains draft in the furnace and finally the gases are

let off to the atmosphere through a chimney about 80mtr high.


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MAIN EQUIPMENT

ECONOMIZER

The main function of Economizer is to preheat the boiler water before it is

introduced into the steam drum. It recovers some of the heat from the flue gases leaking

out of the boiler. The economizer is located in the second pass of the boiler above the air

heater. Each section is composed of number of parallel tubes circuit which is arranged in

the horizontal rows. All tubes circuit originated from inlet header and discharge at outlet

header.

Feed water is supplied to inlet water header via free of stop and check valves. The feed

water flow is upward through the economizer that is in counter flow to the hot flue gases.

Any chance of steam generation within the economizer is eliminated by the upward water

flow that is led to the drum via the economizer outlet link.

SUPER-HEATER

The main function of the super-heater is to superheat the steam. Super heater is

located at the outlet of the furnace.

OPERATION

Before lighting off the unit, open wide inlet and outlet header drains, vents links

drains and main steam line drains. Close all the drains prior to lighting off when the

headers and links appear free of water drain that senses as a starting drain header drain

and is kept open after the unit is on line.


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DE SUPER-HEATER

Mainly the function of De super heater is to reduce the temperature of the steam. De

super heater are provided in super heater connecting links to permit reduction of steam

temp. When necessary and to maintain the temperature at design values within the limits

of the nozzle capacity. Reduction in the steam temperature is accomplished by injecting

spray water into the path of the steam; the spray water source is the boiler feed water

system. It is essential that the spray water should be chemically pure and free of

suspended and dissolved solids. Containing only approved volatile organic treatment

materials in order to prevent the chemical deposition in the super heater.

DRUM

It is necessary to separate the saturated steam from the steam water mixture for

circulation type boiler. This performance is achieved by steam separators arranged in the

drum.


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CAPTIVE POWER PLANT

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


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

auxiliaries.

NEED FOR C.P.P.

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:

1. 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.

2. 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. 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 2 boilers of SGP would be run keeping the 3 rd as stand

by.

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

into parts:

BOILER AND ITS AUXILIARIES : For generation of high pressure superheated

steam.

TURBO-GENERATOR AND ITS AUXILIARIES: To generate power, using

steam from the boiler.


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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.

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:


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DESCRIPTION

MITSUI RILEY TYPE BOILER

Maximum evaporation 2,30,000 kg/hr

Design process for boiler 124kg/cm 2G

Steam temp at outlet 495 0C

Heating surface 1250m 2

FUEL COAL SYSTEM

The purpose of fuel coal system is to pulverize coal to dry coal and to convey the

pulverized coal from ball tube mill to burners by primary air for coal firing.

Fuel coal system consists of three systems:

coal supply system.

primary air system.

seal air system.

COAL SUPPLY SYSTEM

PRIMARY AIR SYSTEM

The primary air system performs two functions. It provides the proper amount of air

required to convey the pulverized coal to the burners and the heat necessary to dry coal so

it can be pulverized and burned efficiently. The details of primary air fan are:-

Coal bunkers

Coalfeeders

Crushersdryers

Ball tubemill


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Make MEIDEN

Degree of protection IP 55

No of poles 4

Frequency 50Hz

RPM 1475

Power factor 0.89

Insulation class F

Rated power 195kW

Type of construction IEC-34

Normal temp rise limit 70 0C

SEAL AIR SYSTEM

The seal air is distributed to the components by the sealing of the mill system by the

sealing air fan. The sealing air fan takes suction from silencer and discharges it to a

common header. The controller for each mill system provides a constant differential

pressure to protect against coal leaking into the bearings and seals. This system should be

in service before being placed in operation.

CRUSHER DRYER SYSTEM

Crusher-dryer performs the CRUSHING function. Metered coal from the feeders blends

with a properly heated amount of air from the primary air fan and enter the crusher dryer.

The non clogging pre crushing flash dryer operates continuously at constant speed.

Rotating hammers drive the incoming coal against a breaker plate and adjustable crusher

block, increasing the surface area of the coal and mixing it with the incoming preheated

air.


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BALL TUBE MILL

Grinding the coal to the proper fineness is done by ball tube mill. The crushed coal and

air mixture from the crusher dryers enter the mill through the mill inlet boxes on both

ends of the mill. The mill barrel rotating at constant speed, contains thousands of

kilograms of various sizes of hardened steel balls which cascade down upon the entering

coal and pulverize it to talcum powder consistency. The heated primary air, entering with

coal, not only completes the drying process, but now conveys the coal dust from the mill

through the mill output boxes to the classifiers on both ends of the mill. The

specifications of the ball tube mill are as:-

Make MEIDEN

Degree of protection IP 55

Insulation class F

No of poles 4

Voltage 3300V

Frequency 50Hz

Current 98A

Power factor 0.89Type of construction IEC-34

Power rating 445kW

Connection Y

Temp. risk limit normal 70 0C

RPM 1430

The pulverized coal from the BTM is fed to the boilers with the help of primary air fans.

The coal is burnt in the boiler to generate steam to move the turbines. The forced and

induced draft fans are used to assist in the combustion of fuel and steam production.

These two major types of fans supporting the units operation.


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FORCED DRAFT FAN

The forced draft fans supply the proper amount of secondary air required to support the

combustion of the fuel delivered to the boiler. The details of the FD fan are:

Make MEIDEN

Rating Continuous

Insulation class F

Rated power 320kW

Voltage 3300V

Power factor 0.85

Current 71A

RPM 980

Poles 6

Connection Y

CAPTIVE POWER PLANT


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INDUCED DRAFT FAN

The induced draft fans control the furnace draft by drawing the gases of combustion

through the boiler, regenerative air heaters, delivering them to the stack. Thus the FD fan

provides combustion air for the furnace while the ID fan removes flue gases from furnace

through chimney. The details of the ID fan are:

Make MEIDEN

Rating continuous

Insulation class F

Rated power 295kW

Voltage 3300V

Power factor 0.83

Current 67.5A

RPM 735

Poles 8

Connection Y

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.


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TURBINE

The turbine used is supplied by M/S SGP of AUSTRIA. 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. HP 1 at 10.4kg/cm 2, HP 2 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

vaccum 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. The resultingcondensate 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. HP 1 and HP 2 are used for heating boiler feed water in HP 1

and HP 2 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.


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Latest instrumentation has been used in this plant. Baileys 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.

DESCRIPTION

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


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UREA PLANT

In this plant 1500 metric tons of uncoated pilled urea per stream day are produced by

signal train wing

The plant can be divided into four sections:

Synthesis Section

Decomposition Section

Recovery & Crystallization

Prilling section

Different steps being carried out in these sections for urea production can be described as

follows:

SYNTHESIS SECTION

In MITSUI TOATSU TOTAL RECYCLE C IMPROVED PROCESS liquid

Ammonia is recycled since it is easier to handle but require equipments like Rectification

Column storage tanks etc. and higher capacity liquid Ammonia pumps.

In this section, urea is synthesized in urea is synthesized in urea reactor CO2 is

received from Ammonia Plant at a pressure of 0.2 kg/cm2 and 20oC and is compressed in

a Centrifugal booster compressor, UGB-101 to 32 kg/cm2 in a 3 stage unit. The

Compressor supplied by M/s BHEL has a normal capacity of 25256 NM3/hr and has 2 barrels 2 M.C.L. 805 and MCL 455. The drive of the Compressor is a extraction and

condensing type of steam turbine supplied by M/s BHEL. The turbine is driven by 40K

super-heated steam and has a rated output of 5792 KW.


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U R E A S Y N T H E S I S

2NH 3 + CO 2= NH 2 COO NH 4 H = - 37.64 Kcals.(i)

NH 2COO NH 4= NH 2 CO NH 2 + H 2O, H = 6.32 Kcals..(ii)

Where as reaction (i) is exotheromic and rapidly goes to completion (ii) is

endothermic and is always incomplete. The overall reaction is exothermic and hence heat

has to be removed continuously for the equilibrium reaction to proceed. The conversion

of ammonium carbamate to urea depends upon:

i) Reaction temp. and pr.

ii) Mol ratio of NH 3/CO 2, H2O/CO 2 of the feed reactants.

iii) Residence time

The conversion increases with the increase of temp. NH 3/CO 2 ratio and residence

time and decreases with H 2O/CO 2 ratio since the presence of water tends to shift reaction

(ii) in the backward direction. The Pr. employed depends on the reaction temp. and has

to kept higher than the dissociation pressure of ammonium carbamate at that temp.

Further since the dehydration of ammonium carbamate to urea takes place in Liq. phaseonly, the Pr. employed must also be higher than the Vap. Pr. of ammonium carbamate

which is rather high.

Higher ratio of NH 3/CO 2 increases conversion and helps to minimize corrosion. As

this ratio increases the load on recovery section increases since excess NH 3 over

stoichiometric requirement has to be recovered and recycled back to reactor. This excess

Ammonia can either be recycled as (a) Liq. NH 3 or (b) carbamate, in which case it

becomes necessary to inject CO 2 into carbamate condensers.

The compressed CO 2 is washed with water in a packed bed tower called methanol

Absorber for removal of entertained methanol in CO 2 which is normally 1000 ppm. The

washed CO 2 is further compressed to a pressure of 260 kg/cm in a two stage compressor,


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UGB-102 supplied by M/s KOBE STEEL, JAPAN. This reciprocating Compressor has a

normal capacity of 26260 Nm/hr and is driven by a 2.2 MW Synchronized motor. Anti

corrosion air at the rate of 65 Nm/hr is fed to CO 2 at the suction of Centrifugal CO2

Booster Compressor.

Liquid Ammonia at 11 C and 18 kg/cm pressure is received in the Ammonia

Reservoir, UFA-401 from the Horton Sphere. Ammonia Booster Pump UGA-404 A & B

booster the pressure of the feed pumps UGA-101 A D. The Ammonia Feed Pumps are

of URACA MAKE driven by 3.3 kV/450 KW and have capacity of 53.2 m/hr., 178

RPM and 89% efficiency. The ammonia feed pumps deliver the liquid ammonia at 260

kg/cm to Ammonia Pre-heater. The pre-heated ammonia at 65 C is fed to the Urea

Reactor at bottom.

The Recycled Carbamate solution of CO 2 concentration, 7.5 Lit per 25 ML, at 105 C

and 260 kg/cm pressure is delivered to the Urea Reactor at bottom by Recycle

Carbamate Solution Pumps UGA-102 A & B. These pumps are centrifugal type and are

driven by backpressure steam turbine, supplied by M/s EBARA of Japan and have

capacity of 81 m/hr.

The three feeds i.e. CO2 liquid Ammonia and Recycled pump solution are fed to a Ti

lined multi wall Urea Reactor. The Urea Reactor is a multi wall shell having wall

thickness of 37mm x 4 = 148mm as thickness. Ti liner thickness is 6mm from bottom to

7900mm, 5mm upto 3950mm, 4mm for next 3950mm and 3mm for rest height. Top and

bottom dish end cladded Layer Urea Reactor. The Urea Reactor is a 12-layered C.S.

vessel with Ti Liner thickness of 5 mm, 4 mm and 3 mm for the 1/6, 1/6 and 2/3rd of

total height of the Reactor from Bottom. The Reactor top temperature is maintained at

200 C maximum. The effluents from Urea Reactor from top are let down to 17.5 kg/cm

pressure through a pressure control valve PCV-101 and fed to the high pressure

Decomposer at 124 C.


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DECOMPOSITION SECTION

MISTSUI TOATSU TOTAL RECYCLE C IMPROVED PROCESS is a conventional

process.

The decomposition reaction, NH 4 COO NH 2-------2NH 3 + CO 2 is favoured by lower

pr. of system or by low partial pr. of one of the reaction products i.e NH3 and CO2.

Conventional Process mean the process where decomposition is affected by lowering in

pressure in successive stages followed by indirect heating whereas the processes where

decomposition takes place by lowering the partial pr. of either NH 3 or CO 2 followed by

indirect heating are called STRIPPING PROCESSES.

The Reactor effluents at 17.5 kg/cm and 124 C enters the upper part of High

Pressure Decomposer UDA-201 having 4 sieve trays at upper and falling film heater at

lower section. The flashed gases go up and liquid flows down through sieve trays. On

trays the high temperature gas from Reboiler, U-EA-201 and falling film heater contacts

with the liquid flowing down. The sensible heat of gas and heat of condensation of water

vapour are used to evaporate the excess ammonia and to decompose the carbamate.

This helps in minimizing water evaporation and thus reducing water recycle to

reactor. The Reboiler further heats the liquid by 12 kg/cm steam to release excess

ammonia and carbamate as gases. The temp. at middle is maintained at 151 C by a

temperature control valve TCV 201. The temp. at bottom is maintained at 165 C

through TCV-202. The falling film heater is used to minimize residence time in order to

reduce Biuret formation and hydrolysis of urea.

Anti corrosive air is fed to high Pr. Decomposer and Reboiler through air compressor

UGB-201 @ 2,500 ppm as air. Overhead gases from HD are absorbed in HAC (High

Pressure Absorber Cooler). The bottom liquid flows to L.D. (Low Pressure decomposer)

at 2.5 K, 145 C Upper Part, having 4 sieve trays. A similar phenomenon occurs in the

low Pr. Decomposer. The Reboiler UEA-202 provides heat using 7 kg/cm steam for


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decomposition and hot stream from H.D. heats up solution from LD in a Exchanger

before entering the upper part. The t emperature is maintained at 130 C at middle by

TCV-203. Small amount of CO 2 is fed below packed bed for improved stripping of

decomposed gases. The over head gases from low Pr. Decomposer are absorbed in low

Pressure Absorber U-EA-402. Bottom liquid flows to 3rd stage of Decomposer called

Gas Separator U-DA-203. The upper part o f gas Separator operates at 106 C, 0.3 K and

lower part with packed bed operates at 92 C and atmospheric pressure. The sensible heat

of solution from low pressure decomposer is enough for evaporating the over head gases.

In the lower part air, containing trace amount of NH and CO 2 is blown under the packed

bed, by off gas recycle blower UGB-401. The Urea solution is concentrated to 70 72%

and sent to crystallization section.

CRYSTALLIZATION AND PRILLING SECTION

The Urea solution obtained from the last Decomposition stage i.e. Gas Separator contains

27% H 2O since for every mole of urea one mole of H 2O is formed. Urea has to be

concentrated to 99.5% before prilling.

MTC C- IMPROVED PROCESS employes Crystallisation remelt Prilling route

and uses spray nozzles for prilling. The prilling tower is of induced draft type.

The solution from Gas Separator enters lower part of Crystallizer, U-FA-201. The

upper part is vacuum concentrator with two stage ejectors and Barometric condenser.

In Vacuum concentrator, operating at 75 m m Hg and 60 C, water is evaporated and

supersaturated urea solution comes down through barometric low into the crystallizer,

where Urea crystals grow. The heat required for water evaporation comes from:

i) Sensible heat of feed urea solution.

ii) The heat of urea crystallization


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iii) Heat recovered by urea slurry circulated through High Pressure Absorber.

The Crystallizer is operated at 60 C and atmospheric pressure, so that slurry

leaving the bottom contains about 30-35% urea crystal by weight.

Hot water from hot water pump is used in jackets of crystallizer and pipe to avoid

crystal build up on vessel walls, which may cause choking otherwise.

The urea slurry is pumped from Crystallizer bottom to Centrifuges U-CF-201 A-E

(1000 rpm, 43 Te/hr of slurry ) maintaining minimum recirculation to Crystallizer to

prevent chocking of lines.

Biruate remains with mother liquor, which after separation from the urea crystals in

the centrifuges is recycled back to the system. Because of excess ammonia in reactor

biurate, thus recycled is converted back to Urea.

NH 2CO NH CO NH 2 + NH 3 ------- 2 NH 2 CO NH 2

(Biuret )

Urea crystals separated from slurry with 2 4 % moisture are discharged to

fluidising dryer UFF-301 at 110 C. The mother liquor flows down to Mother Liquor

Tank, provided with steam coils. Mother Liquor is pumped back to crystallizer via LCV-

207. A part of mother liquor going to low Pr. absorber has been cut off and instead dust

chamber overflow solution has been lined up.

Air is blown from Blower U-GB-301 ( 82360 NM3/hr) and heated to 110 C in air

heater. This hot air dries the crystals to 0.1 to 0.3% moisture content. Dried crystals are

conveyed by a pneumatic duct to cyclones at the prilling tower top. The collected

crystals are melted in melter ( 137 C ) and Urea melt is sprayed through 12 Nos. acoustic

granulators. Prills are cooled in fluidizing bed called CFD, installed a the Prilling Tower

Bottom. Air/cyclone is scrubbed for urea dust in dust separators (2 Nos.). Air containing


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Urea dust from P.T. column is scrubbed with water and passed through 144 sets of

polyurethane filters before exhaust to atmosphere to reduce air pollution.

INSIDE PRILLING TOWER

RECOVERY SECTION

The gases from Gas separator are condensed in off gas condenser UEA-406 to 62 C

and enter the bottom of off gas Absorber DA-402 (OGA). Condensed liquid flows down

to off Gas Absorber Tank UFA- 203. After cooling to 36 C, liquid is sent to top portion

of OGA as absorbent. OGA bottom fluid is recycled as absorbent at OGA middle

position (2nd bed).

Air from top of OGA is blown to gas Separator by GB-401 Blower. The gases from

Low Pr. Decomposer are absorbed in Low Pr. Absorber (EA-402) bubbling a Sparger.

Dust Chamber over flow solution (10-15% Urea) is used as absorbent. Low Pr. AbsorberTemp. is controlled at 45 C and CO2 concentration 2.2 Lit/25 ml.


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Solution from L.A. is pumped by GA-402 A/B to High Pr. Absorber (DA-401)

middle through mixing cooler where liquid ammonia is mixed and serves as medium in

the absorber.

The gases from HD top are bubbled through a sparger in High Pr. Absorber cooler

EA-401, where 65% of CO 2 is absorbed. Remaining gases from HAC go to HA and are

cooled down to 80 C max. in middle cooler at the bottom of H.A. 35% CO 2 is absorbed

in packed bed by a mixture of lean carbamate from Low Pr. Absorber through FCV-401

and liquid ammonia from GA-404 A/B (Temp. 60 C max) through FCV-402. The

scrubbed gas then passes through five Nos. of bubble cap trays in order to absorb residual

CO 2 by a mixture of aqueous ammonia (GA-405 A/B) and liquid ammonia (GA-404

A/B) through FCV-403. Ammonia gas from High Pr. Absorber, Temp. 50 C is pure andcondensed in five Nos.of condensers (EA-404 A-E) and purge condenser EA-403.

Liquid Ammonia flows down to Ammonia Reservoir FA-401. Non-condensable gases

(inerts mostly) flows to Ammonia Recovery Absorber (EA-405 1 to IV). Recovery loop

pressure is controlled by PCV-405 (16.5 17.5 K) at top of EA-405 IV. Cold steam

condensate is fed (FCV-408) for absorption. Aqueous ammonia is with drawn from

Recovery Absorber Bottom by GA-405 A/B.


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IMPROVEMENTS CARRIED OUT FOR AUGMENTATION OF

PLANT CAPACITY

Urea plant at Bathinda has a rated capacity of 1550 Te/day. With retro fittings and

innovative operational practices, the plant is being run at 105-110% on consistent basis.

The retro fittings carried out are listed as under:-

1) CO 2 Booster Compressor

1. The capacity was increased by 3200 Nm/hr by increasing the suction pressure

from 0.08 kg/cm to 0.18 kg/cm.

2. The suction header from Ammonia Plant has been provided with insulation so as

to deliver the CO 2 gas to Booster suction a t a temperature approximately 6 C

lower than the normal value.

2) Ammonia Booster Pumps

Impeller dia of the booster pump was increased from 284 mm to 310 mm and the

motor rating changed from 52 KW to 72.5 KW, the delivery flow of the booster pumps

increased by 10%.

3) Ammonia Recovery System

1. The capacity of ammonia pump UGA-405 was increased from 8.0 m/hr to 18

m/hr.

2. The material of construction of recovery absorbers tubes changed from carbon

steel to S.S.


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4) Prilling Section

1. The conventional spray nozzles for molten urea changed to Accoustic

Granulators. This has improved the product quality considerably.

2. Secondary air flow increased by removing obstructions on air path.

3. Water spray system provided for cooling ambient air during summer months at

the inlet of CFD Blower.

The innovative operational practices introduced is :

Utilisation of Dust Chamber Over-flow solution

The process route of utilization of dust chamber over flow solution via gas separator

has been changed to via low-pressure absorber. This has contributed in increase in

production of about 9 Te/day.

WATER AND POLLUTION

AIR POLLUTION

The sources of air pollution in urea plant is the air from prilling tower which is the

process of cooling of molten urea being sprayed from the top of the tower gets

entertained with urea dust. In order to contain the urea dust emissions in the Exit air, the

air is scrubbed with water and subsequently passes through 144 polyurethane filters

before being discharged to atmosphere. The normal emission level in the exit air is 30-40

mg/Nm against the prescribed norms of 50 mg/Nm.


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LIQUID POLLUTANTS

The sources of liquid pollutants in Urea Plant are :-

i) Dust Chamber over-flow solution

The over-flow dust chamber is being completely utilized after introduction of

innovative operational practice mentioned above.

ii) Dilute urea solution during start-up and shut-down of plant

To take care of the dilute urea solution during start-up and shut down of the plant 3

SS Tanks of 100 m, 100 m and 200 m capacity have been provided. The three tanks

are equipped with steam coils for concentration of the Urea solution. The solution, thus

stored, is reprocessed after the plant conditions are normalized.

iii) C.F.D. Washing

The frequency of CFD Washing is 1 months during summer months and threemonths during winter months. The washed water from CFD containing urea is stored in a

pacca solution pit of 250 m capacity. This pit has been provided with a pump and the

stored solution is reprocessed during normal operation of the plant.

iv) Leaks from pumps and effluents generated during flushing of strainers:

The pollutants generated are diverted to a effluent pit.

The effluent is subsequently sent to the Bio Urea Hydrolyser in the Effluent

Treatment Plant for Hydrolysis of the Urea.


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HYDROLYSIS OF UREA

In aqueous solution, urea is sufficiently stable upto 80 C. Above that temp. it

changes into Ammonium isocyonote and subsequently into ammonium carbonate.

CO (NH 2)2 = NH 4 NCO

NH 4 NCO + 2 H 2O = (NH 4)2CO 3

Which changes into ammonium hydro-carbonate and this ultimately dissociates into

ammonia and carbon-di-oxide.

(NH 4)2 CO 3 = NH 4 HCO 3 + NH 3

NH 4 HCO 2 = CO 2 + H 2O + NH 3

The overall hydrolysis reaction is shown by the equation:

(NH 4)2 CO 3 + H 2O 180 C 2NH 3 + CO 2

NFL has been the market leader for manufacturing and marketing of Urea. The

capacity utilization during the year 2004-2005 has been 106.2%.


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OFFSITES AND UTILITIES PLANTS

D.M. WATER PLANT

Water in its natural form contains a no. of dissolved salts such as sulphates, chlorides

and Nitrates of calcium Magnesium and Sodium. If water is used as such in Boilers for

raising steam, these salts will form scale on the tubes , which in addition to heat losses

leads to many other problems. Hence, removal of these salts from the water becomes

quite essential. ION exchange resins are used for this purpose of salts removal.

The deminerlising water plant of NFL Bathinda was supplied by M/s ION

Exchange (India) Ltd. Delhi.

It consisted of Four units each of Cation, Anion, Primary Mixed bed, and Six

secondary Mixed Bed and three units of condensate cation. At the time of setting up of

captive power plant, another stream to augment the existing capacity of Polish Water

generation was installed by M/s BPMEL. It consisted of one unit each of cation, Anion,

Primary Mixed Bed, two secondary mixed beds and two condensate cations.

Filtered water is received from Raw Water Filtration Plant into two filtered water

reservoirs Feed water pumps discharge water from these reservoirs to cation units. There

are total five feed water pumps each having a capacity of 130 m/hr and four cation units.

Three of these are charged with 13125 litres of cation resin and fourth unit is having

11900 of resin. Cationic lons like Na+, Ca++ and Mg++ present in the water are removed

in the CATION UNITS Once exhausted, these units are regenerated with the counter

current flow of dilute sulphuric acid.

The present day resins are made of cross linked polystyrene and cross linking is

done by Di-vinyl Benzene.


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Cationic resins are made of sulphonated Polystyrene SO 3 H+ can be represented as RH+ .

Anionic resin is similarly made but is chloromethylated and then aminated. The final

product is quarternary ammonium compound a strong base and is represented by ROH.

C A T I O N U N I T

In the cation unit free H+ lon of the resin is replace by Ca++ . Mg++ or Na+ lons

as per the following reactions:

RH + NaCl = RNa + HCl

2RH + Mg SO 4 = R 2Mg+H 2SO 4

2RH + Ca (HCO 3)2 = R 2Ca + 2 CO 2 + 2 H 2O

Neutral salts are converted to respective mineral acid and alkaline salt spilt into

CO 2 gas. The outlet water will have a low pH.

D E G A S S E R

From the cation units water move to degasser. Here free CO 2 content of the

water is stripped off with the help of air by passing the water over rasching ring packed

bed. Water from Degasser is received into three Nos. degassed water sumps each having

a capacity of 40m. From these sumps degassed water pumps discharge water into anion

units. There are total five Nos. of pumps and each having a capacity of 150 m/hr.


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ANION UNITS

Anionic impurities of water besides CO2 and Silica are removed in the Anion

Units. There are total four nos. of Anion Units. Two; units are having 7920 Ltrs. Of

resin while rest of the two are having 5965 and 8400 Ltrs. Of resin. Anions present in the

water get removed as per the following reactions :

2 ROH + H 2SO 4 = R 2 SO 4+2H 2O

ROH+HCl = RCl+H 2O

2 ROH + H 2SiO 3 = R 2 SiO 3 + 2 H 2O

Once the unit gets exhausted, it is regenerated with counter current flow of 4%

NaOH solution.

M I X E D B E D U N I T S (PRIMARY)

Certain amount of sodium and silica ions gets slipped from cation and anion units.Very large volume of resin is required to check these leakage if tackled individually.

Hence, these are removed in mixed bed units. It consists of a bed of mixed cation and

anion resins which acts as infinite pairs of cation and anion units.

A mixed bed unit will produce water of conductivity around 0.5 micro mho/cm. This

water is stored in DM water tanks. These are two Nos. of DM water tanks each having a

capacity of 1500 m. 1400 Ltrs. Each of cation and anion resin is charged in three mixed

bed units while in fourth unit this quantity is 1800 Ltrs.


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C O N DE N S A T E C A T I O N U N I T S

Steam condensate is received from Ammonia, Urea and CPP. It contains lonic

and colloidal iron. Colloidal iron is removed in colloidal filters while ionic iron is

removed in condensate cation units. Condensate coming from Ammonia and Urea Plants

is first cooled to around 45OC in condensate cooler. There are total five Nos. of

condensate cation units. Three units are charged with 1810 Ltrs. Of resin while two are

charged with 4200 Ltrs. Of resin. After polishing the condensate it is stored in DM

Water Tanks.

SECONDARY MIXED BED UNITS

DM Water from DM water tank is pumped to secondary mixed bed units with the

help of DM water pumps, for achieving the desired level of purity of water there are total

5 Nos. of pumps and each having a capacity of 190 M3/hr.in the secondary mixed bed

units final traces of impurities are removed again with the help of mixed bed of cation

and anion resins. There are total six Nos. of these units. Four of these are charged with

1400 Ltrs. Of cation resin and 2200 Ltrs.of ANION Resin while rest of the two are

charged with 1600 Ltrs.and 2600 Ltrs.of cation and anion resins. After passing throughsecondary mixed bed units polish water of following specifications is obtained.

PH : 7 +_ 0.2

Conductivity : 0.2 Micro mhos/cm

Total iron as Fe : 0.015 mg/lit

Silica : 0.015 mg/lit

Hardness : Nil.

Polish water thus obtained is stored in Polish Water Tanks. There are two polish

water tanks each having a capacity of 1500 M3. It is pumped to Ammonia Plant and

Captive Power Plant with the help of five Nos. Polish water pumps each having a

capacity of 220 M3/hr.


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FLOW DIAGRAM OF DEMINERALIZATION OF WATER

COOLING WATER SYSTEMS

The cooling water systems provided at NFL Bathinda are closed recirculating type

supplying cooling water to various consumers in the plant. There are total three systems

supplying cooling water to different sections as mentioned:


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Emergency cooling water pump is in continuous service for ammonia storage area. It

takes suction normally from CT -2; however, provision is there so that it can take suction

from CT-1

DESIGN BASIC

Barometric pr. 971 millibars

Dry bulb temp. 39 0C

Wet bulb temp 28 0C

Degree of approach 5 0C

Relative humidity 81.1% at 31.4 0C

Various other design conditions for all three cooling water systems are given below;

SI no. System Consumer

1. CT-1 Ammonia plant

2. CT-2 Urea plant, boilers,

instrument air

compressors, service air

compressors, caustic

dissolving facility and

sulphur recovery plant

3. CT-3 Crystallization section of

urea plant

4. Emergency pumps (

can be connected

with CT-1 or CT-2)

Ammonia storage area,

instrument air

compressors emergency

diesel set


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INSTRUMENT AIR COMPRESSOR HOUSE

There are four compressors of reciprocating type. Air is sucked from atmosphere and

fed to L.P. stage. Air is compressed at 2.4 Kg & sends to H.P. stage after passing through

intercooler where air compressed up to 9Kg. This air is cooled to - 15 C. It is oil and dust

free.

PERFORMANCE:

TYPE KIRLOSKAR, HITACHI

MODEL TC-BTD-AH

CYLINDER BORE X No.

FIRST STAGE 487mm

SECOND STAGE 267mm

STROKE 200mm

SPEED 590RPM

CAPACITY

At suction conditions 1884mc/Hr At 600 RPM

Suction pressure 0.99 Kg/cm


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BAGGING PLANT

The Bagging Plant can be divided into two main sections:

1. Storage System

2. Reclamation System

Under Storage system, 3 conveyors, come, namely; PJD-101, PJD-102, PJD-103,

PJD-103 is the over head conveyor inside silo. One tripper is provided over PJD-103

which can be placed at any convenient position depending upon the requirement. By

means of the tripper, the material can be poured over any vibrofeeder desired. Tripper is

designated as PJD-104.

The reclaimation system comprises six electro magnetic vibrofeeders, seven No.

of belts conveyors namely PJDs 106, 107,109, 109A Seven No. of weighing machines,

stitching machines & loading platform namely A-0 A-1,A-2, B-1, B-2, C-1 and C-2. In

addition to these there are 3 bunkers / platform, one empty bag storage and one filled

bags storage. By operating flap gate No. 102, the material can be directly fed to PJD-107

without taking it to silo.

The plant has a capacity to load 2250 Te/day of packed material either in Road

Wagons or Road Trucks or in both. The loading platforms can accommodate seven

trucks at a time or three and half BCN Type wagons or 7 CRT type wagons.

The weighing machines are microprocessor based and have speed of 12 to 14

bags per minute. The machines run with an accuracy of +- 50 grams. The system of

counter checking of weight of filled bags is rigorously followed to ensure correct

weightment.


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The plant is provided with a Central Control Room from where the system is

started or stopped. The two systems of Storage and Reclaiming are separately provided

with safety inter-locks to trip the belts in case one belt in the link trips.

The Urea silo is designed to accommodate 30 days production. For reclaiming

Urea from silo, front end Pay Loaders are used.

The plant is also provided with an empty bag Storage and over-head E.O.T. crane

for shifting the bags from the storage to the loading platform.

The filled bags storage is provided for stacking the filled Urea Bags.

Both jute and HDPE bags are used for filling of product Urea. The stitching

thread used is poly thread is used.

The consumption of bags is approximately 104 lakhs per annum and of thread

41600 KMs.

Normally two operators, one Heavy Equipment Operator, 7 stitchers, 7 fillers and

28 loaders besides sealman and weight checking staff are deployed every shift. The Shift

Engineer coordinates the operational activities of the plant and also coordinates with the

Transportation Section for the movement of finished goods.

The spilled urea or the urea from the ruptured bags is recycled back to the system

by 2 bucket elevators, which transport the material from the loading platform to the

Conveyor PJD-109.

Normally Loco-motive is used for shunting of Rail wagons. However, a winch is

also provided to take care of exigencies when the loco-motive is not available.


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PROJECT REPORT

Project Overview:The project gives the brief overview of the project and the main aim is to study about

the description of existing VS new boilers and its accessories.

BRIEF DESCRIPTION OF BOILERS AT BATHINDA UNIT

The Steam generation plants at Bathinda unit have identical 3 nos pulverized coal tired

boilers (VU-40 BHEL make) at each place with design capacity of I50 Te / hr of steam at

pressure 105 ata & temperature 495 C. These boilers were commissioned in 1978.

The Fourth boiler supplied by MES (MITSUI ENGINEERING & SHIPBUILDING CO.

LTD.), Japan is designed to operate at MCR load (230 TPH) either with combination of

coal & FO or FO exclusively. The boiler was commissioned in 1988. Fuel Oil is

continuously used at optimum level as support fuel.

DETAILS OF EXISTING BOILERS: MES Make Boiler: The Boiler (Mitsui-Riley RX type) is of two drums type with

welded wall, radiant and conventional super heaters and economizer. The firing

system is balanced draft type with forced draft fan and induced draft fan and main

fuels are pulverized coal and FO / LSHS. The boiler is of natural circulation type.

MES make boilers are equipped with DCS system (Bailey Japan (now ABB)make Network 90 with MFC 01 controllers and ABBs PPB system as HMI)

for control of process parameters, electrical drives. BMS system is integrated into

the same DCS. Trip interlock is realized through solid-state electronic system of

M/s Bailey. All field instruments are electronic microprocessor.


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EXISTING BOILER PARAMETERS

Unit No. 4

Make MES, Japan

Boiler capacity (TPH) 230 SG

Super heated steam outlet pressure 105 kg /cm

Super heated steam outlet temperature 495 5 c

Fuel Case I Variable Coal + Fixed FO

Case II Variable FO up to 100% MCR

No of Burners 14

Main Burners 6 Dual Fuel Burners (Coal + Oil)

Pilot Burners 6 (with LDO Firing)

Start up Burners 2 (With LDO Firing)

Year of Commissioning 1988

TECHNICAL DATA OF 210 T / HR. CAP. FRONT FIRED

PULVERISED FUEL FEED MESS BOILER.

EXISTING TECHNICAL DATA

BOILER / FURNACE UNIT

Type Of Unit 1 Two drum natural circulation top supported.

Type Of FURNACE Dry bottom front firing.

Steam temperature control 2 stage spray control.

DRUM

Design Code IBR with amendments up to 1985

Design Pressure (kg/cm2g) Steam Drum Water Drum

124.0 124.5

Overall length (Meters) 9.3 8.5

(shell plate length) (7.2) (6.9)

a. Number of Drums 1 1


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b. Drum centre to centre distance 6.5

Internal diameter (mm) 1630/1676 1181/1219

(tube / shell plate side)

Thickness of shell plate 148.7/102.8 108.8/71.2

(min nished thickness)(mm) (tube / shell plate)

Thickness of head plate 96 70

Material IBR IBR REG 234-C. S-47

(equivalent ASME) (ASME: SA-515 Gr.70)

Minimum tensile strength 47

at room temperature (kg/Sq. mm)

0.2 percent proof stress 19.2at design temperature (kg/Sq. mm)

STEAM SEPARATORS

Type Cyclone and dryer carton

Number 31 Cyclones and 32 dryer cartons.

Arrangement Double sided in line

Size overall diameter (mm) 255

BOILER BANK

1) Arrangement In line

2) No of gas passes 1

a. Heating surface (M2) Furnace 1250

Bank 1000

b. Furnace volume (M3) 990

HEADERS

Location Nos. Size Type Of Connection

OD(mm)


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a. Lower front Furnace 1 406.4 Welded

b. Lower rear Furnace 1 406.4 Welded

c. Lower sides Furnace 8 273.1 Welded

d. Upper sides Furnace 8 273.1 Welded

ECONOMISER

Type Bare Tube

Tube spacing(mm)

a. Vertical 88.9

(transverse to gas flow)

b. Horizontal 63.5

(Parallel to gas ow)

Tube arrangement In-line

Number of assemblies 28

(transverse row to gas ow)

Number of assemblies 44

(Parallel row to gas ow)

a. Direction of gas ow Down ow

b. Direction of water flow Up ow Tube material IBR IBR REG 36/42-C, S -41/51-S-C

(equivalent ASME) (ASME, SA-210 Gr. A1)

Size of tube OD (mm) 63.5

Heating surface m2 (approx) 1520

Header diameter, Length and thickness(mm) 2 73.1 4740, 30

SUPERHEATERS Design Code IBR with amendments up to 1985

Design pressure (kg/cm2g) 124 LTSH ITSH HTSH

a. Type Pendent Pendent

b. Number of assemblies 7 38 38 19



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c. Number of elements per 66 24 8 8

assembly

(parallel row to gas ow)

Flow Parallel Counter Combined

a. Tube diameter (mm) 44.45 63.5 57.15 50.8

b. Tube thickness (mm) 4.4 6.3 5.7 5.1

c. Transverse pitch (mm) 812.8 152.4 152.4 304.8

d. Longitudinal pitch (mm) 50.8 127 114.3 101.6

Material IBRREG ASME ASME IBRREG

(equiv. ASME} 56A-2.25 SA- SA- 56A- 2 .25

CRIMO 213 213 CRIMO

-39-S-C Gr. Gr. -39-S-C

(ASME SA-213 T11 T11 (ASME

SA-

Gr, T22) 213 Gr,

T22)

No of groups 7 38 38 19


Tubes per group 66 24 8 8


DESUPERHEATER FOR SUPERHEATER a. Type of De-superheater Water spray

b. Number 2 (1 SETS for 1st STAGE)

(1 SET for 2nd STAGE)

c. Material 11/4 Cr-1/2 M0 (ASTM A182 Gr. P11)


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d. Necessary piping, valves Yes

and ttings provided.

e. Size (mm) 1st stage 2nd stage

(inside DIA) 25.4 38

REGENRATIVE AIR HEATER

Type Ljungstrom

Bearing Type & Size Thrust bearing 780 mm

Basket material

-cold end Corrsion Resistant Low Alloy Steel

-Hot end Mild Steel

Arrangement Vertical

Number of passes 1

Effective height of Cold end Hot end

Baskets (mm) 300 1950 (2x975)

Heating surface total 12340

(approx) (m2)

STEAM COIL AIR PREHEATER

Type Fin Tube

Aux_ Steam Parameters

- Flow (kg/hr) 4010 (LSHS at 100% MCR)

- Temp (C) 300

- Pressure (kg/cm2) 11

Construction details Welding Type (Header to tube)Overall size (mm) 2815L x 655W x 4245H

Design Temperature (LSHS 30% MCR)

- inlet (C) 30

- Outlet (C) 100

Heat transfer area 814


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provided (m2)

Tube outside dia x approx. 16 x 2 x 38

Thickness x pitch

(mm x mm x mm)

FEEDERS

Type and Make Type: Gravimetric feeder

Make: Yamato scale Co., LtdCapacity max. 17 ton / h. feeder

Overall dimensions 4.1L X 2.0w X 1.8w (m)

Reference to dimensioned Ref. No. EO18

sketch

Construction materials Body: Carbon steel

Inner surface Stainless steel

Accessories provided Ref. No. EO18

Motor rating, type make ditto and 0.75 KW for weighing conveyor

0.40 KW for clean-out conveyor


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DETAILS OF PROPOSED FUEL CONVERSION WORK FUEL

CHANGEOVER FROM FO / LSHS TO NG / RLNG IN MES

BOILERS (BOILER #4)

The upgrade for fuel change over project of each plant broadly comprises of following

sub systems:

a. New Pulverized coal cum NG Fired Burners equipped with gas ignitor and flame

scanner.

b. Burner Register dampers (Manual operated / Auto operated Secondary air damper

along with actuators.

c. Modification of Wind box to install the new along with insulation and cladding.d. Burners throat refractory modification.

e. NG Piping from pressure reducing station to Boiler #4.

f. NG control station and field instruments for monitoring and safety shutdown.

g. NG train to burners with safety shut off valve.

h. NG piping for igniters / support firing.

i. New DCS system for BMS and boiler operation and control.

j. Cabling from field instruments of NG system to the new DCS panels.

DETAILS OF PROPOSED FUEL CONVERSION WORK FUEL

CHANGEOVER FROM FO / LSHS TO NG / RLNG IN MES

BOILERS (BOILER #4) INSTALLED AT BATHINDA

The upgrade for fuel change over project of each plant broadly comprises of following

sub systems:

a. New Pulverized coal cum NG fired Burners equipped with gas ignitor and flame

scanner.

b. Burner Register dampers (Manual operated) / Auto Operated Secondary air dampers

along with actuators.


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c. Modification of Wind box to install the new burners along with insulation and

cladding.

d. Burners throat refractory modification.

e NG Piping from pressure reducing station to Bolier #4.

f. NG control station and field instruments for monitoring and safety shutdown.

g NG train to burners with safety shut off valves.

h. NG piping for igniters / support firing.

i. New DCS system for BMS and Boiler operation and control

j. Cabling from field instruments of NG system to the new DCS panels.

RECEIVING, INSPECTION, HANDLING STORAGE AND

INSTALLATION INSTRUCTION OF NEW PC S TYPE

BURNERS

RECEIVING, INSPECTION AND HANDLING

Conrm receipt of all equipment on each Bill of Material. A systematic inventory

procedure for the storage area will facilitate retrieval and installation. Inspect the burners

for damage upon receipt and prior to off- loading to storage. Conrm the bracing is in

place and secure and that damage did not occur due to shifting in transit. Ln particular,

inspect the linkages, operator handles, and pilot taps to conrm no pieces are bent or

broken. Confirm the vane drive rings are properly arranged on the guides and have not

moved during shipment.

The PC S Type Burners are to be off-loaded into a suitable storage area using the lifting

lugs. These components are shipped on pallets which are intended to protect the

equipment during transport and storage, but the pallets are not suitable for lifting by

forklift. Do not lift the burners or ports using the barrel stiffener bars or any other burner

hardware except the lifting lugs.The burner weight is approximately 2200 kg, not including the actuator or burner elbow

The burners should be left attached to their pallets to prevent damage to linkages, drive

rings, etc. until immediately before lifting to install on the walls. lf for some reason the


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pallet must be removed ahead of time, blocking must be used to prevent damage to

components.

STORAGE

The PC S-Type Burners have the following short-term (3 months or less) storage

requirements:

a. The burners to be stored in such a manner as to protect them from water and dirt and to

avoid damage from collision and falling objects or debris. They are to be left on their

shipping pallets while in storage.

b. All electrical and electronic equipment are to be stored indoors in a semi- controlled

environment with a non-condensing atmosphere.

c. All small loose pieces (bolts, nuts, clips, etc.) will be adequately prepared and packed

for protection against rust and impact damage. These are to be stored in such a manner as

to protect them from water and dirt, and to avoid damage from collision and falling

objects or debris. These should be stored in their shipping containers until they are

needed for installation.

INSTALLATION INSTRUCTIONS

General

The following instructions describe procedures to remove PC fired burners and install PC

S-Type Burners. Removal instructions are provided for future reference, for the unusual

situation where removal is necessary to facilitate major maintenance or for burner

replacement due to catastrophic damage of some kind. Installation instructions are

provided as they combine with burner replacement. For initial burner installation as part

of new boiler construction, installation will generally commence with item F. Consult the

respective Erection Arrangement drawings for Erection Notes and further detailed

information. The Erector is to determine the most suitable means of removing the

existing burners and installing new burners. Each burner elevation and location needs to

be checked, taking into account access and interferences with platform steel, building


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steel, auxiliary equipment, steam piping, fuel piping, cable trays etc. The erector must

identify and install new burners in their appropriate locations by burner or port number,

as per General Arrangement drawings. Numbers are stencilled on each burner.

Very important point : Prior and during the erection I installation of the burners please

note to take Care regarding burner swirl orientation which is CW - Clockwise direction or

CCW - Counter Clockwise Direction as per the burner drawings. The direction of burner

orientation CW and CCW is to be ascertained by standing in front of the wind box on the

firing oor prior to installat ion and carrying out full welding. Follow welding

requirements in accordance with the drawings.

BURNER DATA

Size & Type of Burner 18" Coal Nozzle and 38" PC S-Type

Emission Guarantees by Burner NA

No. of Burners per boiler Six (4 Operating + 2 Standby)

Capacity of each Burner (%MCR) 25%

Type of air control & accessories Lead lag arrangement, FD fan Inlet guide

Vane

Burner Throat Dia, inch 38"

Type & No. of Gas spuds One No. Super Spud (Main Spud)

Construction of Spuds Fix SpudSwirler/ impeller information Impeller

Burner turndown (Coal) 1: 2.25

Burner turndown (NG/RLNG) 1:4

Q Fired per Burner, Mkcal/hr 40.0

Total Fuel (NG / RLNG) Fired, kg/hr 12550

Fuel (NGI RLNG) Fired per Burner, kg/hr 3138

Minimum Fuel (NG / RLNG) Fired per Burner,

kg/hr

785

Burner Inlet Pressure during maximum Fuel

(NG/ RLNG)Firing, kg/cm2

0.7

Burner Inlet Pressure during minimum Fuel

(NG / RLNG) Firing kg/cm2

0.05


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Main NG Header Pressure Very High Trip

kg/cm2

1.5

Main NG Header Pressure Very High

Alarm,Kg/cm2

1.4

Main NG Header Pressure Very Low Trip

Kg/cm2

0.01

Main NG Header Pressure Very Low

Alarm,kg/cm2

0.02

NOTES:

4 Burners (any two levels) may be operated during PC firing.

Performance of PC Burners is subjected to Pulverized Coal size at the burner inlet as

below

99% passing through 50 mesh

75% passing through 200 mesh

Any four Burners in two elevation (Bottom & Middle) suggested to be operated during

solo NG ring for the load range of 70% to 100% MCR. Based on the actual performance

of the Boiler on solo NG firing (particularly the SH performance) the operation

philosophy will be finalised and provided.

NEW PC-S TYPE BURNERS

INTRODUCTION

The burners are of Babcock & Wilcox (USA) design. Type PC "S Type" with Central

NG Gun Gas Spud, total 6 Nos. burners installed on each boiler, mounted two abreast

endosed in the existing wind box which is mounted on the boiler front wall. the burners

are dual fuel fired capable of firing Pulverized coal and Natural Gas up to 100% MCRSteam generation. The offered burner is proven and in operation world over supplied by

Babcock & Wilcox(USA). The burners are Designed. Engineered and Manufactured by

Thermax Limited Pune under the technology transfer agreement between the two

companies The indnidual burners are designed to operate only as follows:

a. Individual burners on Solo Pulterised Coal or Natural Gas firing.


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b. Burners can be fired in combination firing mode with Natural Gas and Pulverised Coal

together. Individual burners on Variable Pulverised Coal firing and Variable Natural Gas

Firing (During Pulverised Coal firing the burners shall start in a pair only of the

designated elevation selected by the operator)

The burners have the capability to fire Pulverized coal equivalent to 100% steam

generation by operating any 4 numbers (any two levels) with 25% NG support firing

through the main NG burners i.e. Minimum 6.25% each burner capacity. It is always

advice to keep the pilot burners firing NG in operation till PC firing is stabilised.

Each PC S Type" bu rner is equipped to fire pulverized coal up to maximum rated burner

input of 40.0 Mkcal/hr At this input the unit can be operated at maximum rated load withany two of the three mills in service while supplying pulverised coal to four (04) burners.

The burners are installed and located in a common wind box. where secondary air

admitted to the wind box is equally available to all the burners.

Each burner is equipped with an FPS gas-fired igniter.

GENERAL INFORMATION & DESCRIPTIONS

GENERAL INFORMATION

The PC S Type burner offers more reliable field performance through improvements in

mechanical and functional design The PC S Type burner is ideally suited for front wall

fired units The PC S Type burner provides for independent control of air flow and air

turbulence to each burner. Secondary air flow to the burner is controlled by the positioing

of an adjustable sliding damper installed at the entrance to the air sleeve.

TO Provide proper mixing of the fuel and air swirl is imparted by means of adjustable

spin vanes located in the air sleeve The burner orientations are as follows;

CW Clockwise burner.

CCW Counter clockwise burner


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The orientation of the burner depends on the direction of opening of spin vanes. If the

spin vanes are opening in the clockwise direction then the burner is CW and vice versa as

viewed from boiler front/firing floor. An air flow monitor located in the air sleeve

upstream of the spin vanes, allow for air measurement to individual burners and

facilitates balancing of air flow on multi burner applications. Thus it provides a local

indication of relative secondary air flow to facilitate sliding disk adjustment to balance

SA among the burners. Hence individual burner combustion air differential pressures

(Differential Pressure) "DP" can be measured in mmwc.

SECONDARY AIR DISTRIBUTION AND CONTROL .

Secondary air is provided from two FD fans (Existing) and is preheated initially in two

Steam coil air preheaters (Existing) and later in common Regenerative Air Heater(Existing) Flow control of this air is provided by FD fan inlet Vane. Secondary air, along

with primary air, is controlled to satisfy theoretical and excess air requirements for good

combustion throughout the operating range during coal firing. The secondary air flow

shall always be kept at 30% of the MCR air flow flowing through all the burners nearly

equally during tho first light up or cold start of the boiler on NG firing with a single

burner In addition. total boiler airflow is always maintained at or above 30% of full load

air flow ensuring the total boiler airflow is always throughput which shall not be reduced

below the purge flow rate of the boiler regardless of load.

Hot secondary air (SA) entry from the air heaters flows toward the furnace through

bottom portion of the wind box of the unit. Hot SA duct is equipped with an air flow

(Existing) measuring device. The secondary air flow is subsequently distributed to the

burners.

The SA is freely admitted to the burner wind box and available to all burners in that wind

box, SA flow to each burner is regulated by an automated pneumatic actuator device

which controls the burner adjustable sliding air damper at the entrance to the air sleeve.

SA enters the burner past the sliding air damper, continues through the burner throat

adjustable spin vanes located in the airsleeve and exits through the burner throat into the

furnace To provide proper mixing ol the fuel and air, swirl is imparted by means of

adjustable spin vanes located in the air sleeves.


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COAL FlRlNG 0PERATlON AND ADJUSTMENTS (EXISTING NFL SCOPE)

The Pulveriser / Mill primary air damper controls the primary air flow rate to the burners,

while the coal feeder controls fuel flow. The burner line isolation valves are intended to

isolate the pulveriser and related equipment from hot furnace gases and provide rapid and

positive fuel shut off. These valves should always be either fully Opon or fully cloud,

They should never be used to adjust coal rate to the burners. The ratio of primary air to

coal shall be [email protected] C, as well as the temperature of the mixture, is established to

satisfy several pulveriser and burner requirements,

Normal coal/air temperature exiting the pulveriser is about 79.50 C. Excessively hightemperatures lend to cause choking in the burner nozzle, and increase the Possibility of

nozzle fires. Low temperatures can result in Insufficient drying of the coal, pulveriser

choking and poor combustion. Operating with high primary airflow will tend to decrease

coal fineness, adversely affecting combustion and increasing unburned carbon, High PA

also increases erosion and can cause flame instability. Low primary air flow may result in

plugged burner lines, burner line fires, dribble at the pulveriser, and poor coal distribution

discharging from the coal nozzle.

Natural Gas fired igniters are provided on the main burners and are of Continuous duty

equivalent to 10,0% capa city of main burner These ignit ers are must to be kept in

continuous services firing natural gas throughout the main PC burner operation on

pulverized coal while the pulverised coal is being delivered from each pulveriser and

burner, These igniters are firing natural gas as a support flame to the main pulversied fuel

in order to be self sustaining and stabilize the main flames of pulverised coal at

conditions when flames may not be self-sustaining. Flame stability, while firing coal, is

impacted by several factors. Primary air flow and coal / air temperature have already

been discussed. ln addition, the ignition properties of the coal are of prime importance.

Key factors include the quantity and quality of volatile matter; and the quantity of inert

matter (ash and moisture). Coals with lower volatile matter and/or increased inert matter

will result in reduced flame stability. Boiler load and load on the particular pulveriser will


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also Impact stability, as will the firing pattern of burners in service. Below 40% of the

respective capacity of the pulveriser the flames are not expected to be self sustaining and

Stable. Flame stability has to be assessed during early operation on coal. These

assessments have to include reduced load conditions on the boiler and on individual

pulveriser/burners, Flame scanners are also installed on the main PC fired Burners which

are intended to safeguard operation and prevent burner operation without stable and

satisfactory flames.

Control of the fuel to active burners and airflow to burners is best accomplished by

properly adjusted automatic combustion controls. Conditions may arise where automatic

Operation is not possible or not desirable for both the fuel and air. In these cases, operate

with both in manual operation Always operate with the fuel and air controls in the same

mode either both on manual or both on automatic.Combustion system tuning is performed to determine the optimum operating for the PC S

Type burners, The PC S Type burner spin vane settings are to be finalized for all burners

during early operation ring pulverized coal. The final settings should be flirty uniform

tor all burners. The burner air dampers are positioned by automated linear actuators for

appropriate Cooling or light off position, and operating position. with specific settings

determined for each burner. Coal and air distribution to the furnace and resultant ow

patterns through the furnace, change in correspondence to which pulversiers are in

service.

Tuning it performed varying which pulverisers are in service to determine and

nfl-bathinda final.docx

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