FUEL HANDLING SYSTEM OPERATION

STAGE – I

O &M MANUAL

LIGNITE HANDLING SYSTEM

(LHS)

CHAPTER - I

1. LIGNITE HANDLING SYSTEM (LHS) – STAGE – I

1.1 GENERAL DESCRIPTION

Power Generation is one of the many mine-mouth operations at

the coal mine. Moving coal from Mine to Power station continuously as well

as adequately is the biggest task. Any failure in mining activities or and

fluctuating power demand at power station certainly affect the functions at

both ends. So , a system should be designed in between which must have

more than ordinary prominent feature of coal mining. Whether from

technological or economical point of view, the reliable and efficient handling

of coal at various stages is a matter of prime concern to a power station.

In Neyveli a soft, low calorific brown coal “LIGNITE” is being

mined and transported to Thermal Power Stations. A typical handling system

has been incorporated in Thermal Power Station-II for transporting lignite

excavated from Mine-II. Lignite handling system of TPS-II has been designed,

manufactured and supplied by M/S. BUCKAU-WALTHER, AKIENGES CELL

SCAFT, WEST GERMANY. It consists of 2 series namely A & B and each is

capable of handling maximum of 2800 T/hr. Lignite from Mine-II is received

at Junction Tower-II. The lignite can be diverted from JT-II either to crusher

house or to storage yard.

A crusher house has been installed in between Junction Tower-I

Transfer Tower-I, to screen and crush the lignite. Magnetic separators and

metal detectors are located at appropriate places to safeguard equipment’s

in LHS as well as lignite firing system in the Boilers. Separate bunker bays

with arrays of conveyors are provided for Stage-I and Stage-II Boilers.

1.2. RECEIVING SYSTEM

Receiving System consist of Junction Tower-II, Con-1(CC1 & CC2

Conveyors), con-2, & con-3. apart from conveyors 1,2,& 3 there are 2 parallel

conveyors namely 7A & 7B starting at Transit Tower-I (TT-I) passes through

Junction Towers-II (JT-II) and end at the top of Crusher House. Both 7A & 7B

conveyors are below Con-3.

Normally the Lignite from Mine-II is received through CC-I & CC-2

at Con-3 and sent to storage yard. In this case, the Con-3 receives the Lignite

and feed the Lignite to Con-2, in turn taken to storage yard through a

Stacker. The stacker is to be placed at the suitable place for storing the

lignite. Con-2 runs between the stock piles No.1 and No.2 . The stacker

moves on the rails and it can feed both stock pile No.1 and No.2. Con-3 is

short length shuttle conveyor. Storage yard consists of stock pile No.1 (4A

side) capacity being 80,000 tones on the southern side of conveyor-2 and

stock pile No.2 (4B side) capacity being 70,000 tones on the northern side of

the conveyor-2. Stock pile–1 includes the cover shed storage of 10,000

tones. Cover shed storage hall length is 85 meters. Height of stocking is

10.5 meters. Length of stock pile No.1 is 600 meters, stock pile No.2 is 515

meters length. In the closed storage area stacker will have slewing angle of

90 degree only. Minimum lignite bed thickness of 400mm is provided for

preventing the pebbles coming into contact with the bucket. It

also prevents the damage of reclaimer. Pebbles bed facilitates effective

water drainage during rainy season. Sump pumps are provided on both sides

of stockpiles to pump out water from stock piles. Total belt length of

conveyor-2 is 1450 mts.

A modification has been introduced in receiving system for

receiving lorry load from B& C plant. A conveyor 3.2 is provided for receiving

and transferring to stock yard through con-2 and stacker.

1.2.1. DESCRIPTION OF STACKER

1. Type B1800-19.9

2. Capacity 2800T/Hr(or)3730 M3/Hr

3. Max stacking height 13 Mts

4. Angle of repose 390 approx.

5. Rail type S 54

6. Slewing angle 1800

7. Track inclination 0.1 %

8. Travel speed 6&15 Mts/min.

9. Hoisting speed 5Mts/min.

10. Slewing speed 9Mts/min

11. Belt speed & size 4.20m/sec & 1800mm

12. Drive pulley 1000X2000 mm Brg

No.23148

13. Tail pulley 800X2000 mm Brg No.23140

14. Tipper discharge pulley 1000X2000 mm Brg No.23148

15. Splash lub gear box 200 kW coupling SX 290

16. Other pulleys 800X2000 mm

17. Slewing gearbox Bevel Planetary

18. Travel drive 4Nos 3KW/7KW

19. Rail gauge 4m

1.3. TRANSFER SYSTEM

1.3.1. DIRECT LOAD

If lignite is required to be diverted to boiler bunker directly, the

CC-2 can feed to Con-7B by positioning the con-3 at its east extreme called

“Direct Load”. In this condition con-3 need not run.

1.3.2. BIFURCATION

A new modification has been introduced in receiving system is

called Bifurcation. In this method the lignite receiving from Mine-II is being

transferred to boiler bunker (60%) and storage yard (40%) In this condition

Con-3 is positioned at bifurcation position. Travel limits are modified for this

purpose. Thus con-3 can be positioned and run as per our requirements.

Con-4A and 4B located along stock pile No.1 and 2 respectively.

Both conveyors 4A and 4B are equipped with reclaimers, one on each.

Reclaimers are mounted over rails of 6.0 meters gauge, Reclaimers can be

slewed to 1800

Conveyors 4A and 4B drive heads are located in transfer tower1

and 2 respectively (TT1 and TT-2). In TT-1 and TT-2 conveyors 6A and 6B are

positioned just below the drive heads of conveyors 4A and 4B respectively

and above conveyors 7A and 7B. Lignite can be fed from Con-4A to either

Con-7A or con-7B by altering the position of the Con-6A if Con-6A is

positioned at extreme right i.e. yard side lignite will be fed to Con-7B and

Con-6A will not run. If Con-6A is positioned at middle, lignite will be fed to

Con-7A. In this position

Con-6A will be in running condition. Similar arrangement exists from Con-4B

with Con-6B. During rainy season Con-6A & 6B can be positioned out

extreme on road side and water and slush lignite can be diverted out of the

system. This position is called throw off position. A similar arrangement exits

in conveyor-4B also. Reclaimer in conveyor-4A has a rail length of 600

meters and effective travel is 580 meters. Reclaimer in conveyor 4B has a

rail length of 515 meters and effective travel is 490 meters. Conveyor 4A

and 4B’s length is1300 meters. (Each belt length) Belt tension of Conveyors

4A , 4B and con-2 is adjusted by electrically operated winch.

Magnetic separators are installed above the drive heads of

conveyor CC-2, 4A, 4B, named as MS-1A, 5A, 5B, respectively. Another 2 no.

of Magnetic Separators named MS 7A & 7B are provided across con 7A & 7B

respectively. Metal detectors are also provided across con-7A and 7B to

detect ferrous materials and in turn to avoid the damages in crusher.

1.3.3. MACHINE RA AND RB DETAILS

There are two reclaimers called M/C-RA and M/C-RB. In each

machine contains platform, mast, bucket wheel boom, counter weight boom

and bucket wheel conveyor with transfer point. The slew movements of it

are introduced by two slew assemblies located on the superstructure

platform. The rotating connection between the superstructure and

undercarriage circular frame is formed by a roller race which safeguard the

machine against lifting and also absorb alternating axial and radial loading

with high tilting moment.

The bucket wheels with its conveyor area are mounted in the

bucket wheel boom. It can be raised or lowered by a hydraulic cylinder. The

bucket wheel body is of welded design with stiffener ribs welded in place and

with connecting lugs for fixing the buckets. There are 10 fitted buckets. The

buckets are formed by welding side plates, transition plates and welded

together to form a unit. The bottom of the bucket has a mat of chains or

rubber for better bucket emptying. All the buckets are connected to a rim

and which in turn connected to one end of hollow shaft assembly other end is

connected to bucket wheel gear box.

The main drive for bucket wheel is coupled by means of a fluid

coupling. This coupling serves as starting and safety coupling to protect the

drive and reclaimer from detrimental overloading.

The counter weight boom is a torsion resistant truss construction

whose lower fork shaped part is bolt connected to the hinge of pivot point of

the bucket wheel boom. The mass is also similar to counter weight boom

construction and it is also connected to bucket wheel boom.

Bucket wheel boom is buffed by a hydraulic cylinder installed

between bucket wheel boom and superstructure. Bucket wheel conveyor

with a belt conveyor is installed in the bucket wheel boom.

1.3.4. SPECIFICATION OF RECLAIMER

1. Type : SCH-ss-1000-12.3

2. Capacity : 2200 T /Hr(or)2800M 3

3. Angle of Repose : 39 0

4. Slewing angle : 180 0

5. Bucket capacity : 850 ltr. No of Bucket 10

6. Ring volume : 150 ltr.

7. Bucket wheel speed : 6.4 RPM.

8. Travel speed : 6 & 15 M / Min & 3 /7

KW

9. Slewing speed : 30 mtrs / min 11 Kw DC

10. Hoist /Lower speed : 5 mtrs / min

11. Bucket wheel power : 155 KW / 105 KW

12. Boom con. Power : 132 KW

13. Belt : EP 4 / 5 Gr 24

14. Drive pulley : 1000 X 1800 mm

15. Tail pulley : 800 X 180 mm

16. Travel drive : 8 Nos.

17. Rail gauge : 6 m.

1.4. CRUSHER HOUSE

In this house, lignite is sized and supplied to the units. Facilities

are also available to have an interchange between A and B series conveyors.

It is located in between Transfer Tower-II and main power house or junction

tower-I. The parallel conveyors 7A and 7B having upward inclination reach

the top floor of crusher house. The conveyors 7A and 7B feed lignite to 9A

and conveyor 9B respectively. Conveyors 9A and 9B are unidirectional

stationary conveyors and are running to a direction perpendicular to

conveyors 7A and 7B. Hence a 900 turn in flow path is made. The width of

these conveyors has been increased to avoid any spillage while transfer.

Conveyor 9A feeds lignite to Eccentric disc

screen (10A) where as 9B feed to another screen (10B). Due to lot of

problem in screen and crusher, and also to avoid single stream in crusher a

new modification has been introduced called “SCREEN AND CRUSHER BY-

PASS”. For this purpose travel provision has been made in con-9A. In this

condition con-9A can be traveled and positioned in con-12A bypassing the

screen and crusher. i.e. Con-9A load is directly goes to con-12A through

vertical chute. Con-12A and con-12B are shuttle conveyors, can be

positioned either to con-14A or to con-14B. Belt tension of con-14A/14B and

con-7A/7B is automatically adjusted by the counterweight provided in these

conveyors.

1.4.1. ECCENTRIC SCREEN

Two number eccentric disc screen of Type SRH 25/19 are

provided in the crusher house just below the discharge point of conveyors 9A

and 9B. These eccentric disc screen are designated as 10A and

10B’respecively and are having 2800 T / Hr. capacity each. They are

installed mainly to separate higher size lignite (more than 80 mm) and to

divert these coarser particles to crushers. Normally maximum lignite size is

assumed as 400 mm and corner to corner size is assumed as 600 mm.

1.4.2. JUNCTION TOWER

In this place lignite either from mine or from stockyard can

be diverted either to Stage-I or Stage-II boilers or to both. The lignite from

conveyors 14A/B can be diverted to II stage boilers with the help of

conveyors 17A/B . Con-17A can feed to the Con-18C and con-17B feed to the

con-18D. In this condition both the conveyors ie., Con-17A and Con17B

should run and

positioned to stage-II. If Con-17A positioned to Stage-I the conveyor running

is not necessary and fed to con-18A. A new conveyor has been introduced at

JT-1 called 17X. This conveyor has been positioned at four positions.

Position-I (Chute positioned to con-18B con-17X,not necessary to run).

Position-II (Con-17X running forward to feed the con-18A). Position-III (Con-

17X positioned to con-14A, and 17X running reverse direction to feed con-

18B). Position-IV-Idle position. 17X helps only for stage-I feeding from Con-

14A or Con-14B.

1.4.3. STAGE – I BUNKER CONVEYORS

Over the boiler bunkers, conveyors are arranged in 3 elevations.

The parallel conveyors – 18A / B receiving lignite from conveyor-14A / B,

accents to 37.9 meter level and feed lignite to the parallel conveyors- 20A/B

at 34.9 meter level. The conveyors-20A / B are intermediate

conveyors to transfer lignite to boiler 1and 3 bunkers of boiler-2. At 31.28

meter level, 4 reversible shuttle conveyors namely con-21A1/ A2 and 21B1

/B2 are moving on the rails. Out of four, two (i.e. 21A1 and 21B1) are used to

fill six bunkers ( 3A to 3F) of boiler and three bunkers (2A to 2C) of boiler 2,

the other two ( i.e. 21A2 /B2) used to fill up remaining 3 bunkers of boiler 2

(i.e. 2D to 2F) and six bunkers (1A to 1F) of boiler 1.

1.4.4. STAGE – II BUNKER CONVEYORS

Bunker bay of Stage- II units (ie) Unit 4 to 7 is located other side

of Junction Tower-I. Arrangement of conveyors are similar to that of Stage-I.

The conveyors available are namely 18C/D, 21C1/D1, 20C/D, and 21C2/D2.

Conveyors 21C1/D1 are rail mounted reversible shuttle conveyors. Conveyor

21C1/D1 receives lignite from 18C/D respectively where as conveyors

21C2/D2 gets lignite from 18C/D via., 20C/D respectively. Conveyors

21C1/D1 fed lignite to unit 4 & 5 and con21C2/D2 feeds to unit-6 & 7. Belt

tension of con-20A/B/C/D and 18C/D is adjusted automatically by the

counterweight provided in these conveyors. Dry fog type dust suppression

system is provided right from TT1 to JT2 at every transfer chutes and at

bunker for dust free atmosphere. Fire protection system is provided along

the 7A/B and 14 A/B galleries.

1.4.5. AUTOMATION OF BOILER BUNKER FILLING

Automatic bunker filling has been introduced in Stage-I and

Stage-II with this system bunker level can be monitored from control room

for both Stage-I and II. Closed circuit television has been provided to view

different vital locations.

1.5. MULSIFIER SYSTEM

Automatic mulsifier system has been provided along con-7A/B

and con-14A/B.

1.6. DUST SUPPRESSION SYSTEM

Dry fog type dust suppression system is provided right from TT-1

to bunker conveyor at every transfer chutes and at all bunkers for dust free

atmosphere.

Automation of boiler bunker filling has been introduced in Stage –

I and Stage –II. Dry fog type dust suppression system is provided right from

TT-1 to bunker conveyor at every transfer chutes and at all bunkers for dust

free atmosphere.

1.7. LIGNITE HANDLING SYSTEM (LHS) - OPERATION

1.7.1. LHS CONTROL ROOM

Operation of Lignite Handling System is done by control room

Executives manning each shift. All the units Stage-I and stage-II are filled

twice in each shift. The Control room executives co-ordinate with Mine-II

bunker for receiving lignite and stacking in the yard. The receiving system

consists of stacker, Conveyor-2, conveyor-3 and MS-1A which can all be

started from control room panel in control room. The machines (Stacker,

Reclaimer-A and reclaimer-B) are run by SME/Operators. The yard is

inspected in the beginning of the shift and lignite received on either RA or RB

side depending on the situation. Aim is to maintain full quantity in cover

shed in RA side and to maintain equal loads on both RA and RB sides. Before

asking the stacker operator to start the machine the following points need to

be checked.

1. Availability of stacker, conveyor-2, conveyor-3 and MS-1A

2. Whether the stacker rails are clear.

3. Whether any work is pending (pending LS’s)

4. Availability of load in Mine-II.

5. Whether it is desirable to divert load partially or fully to

boiler bunker. (Route-I direct load to boiler bunker, Route-II

Mine-II to Stacker, Route-III Internal transfer system from M/C ,

yard to bunker – Bifurcation i.e. around 60% to boiler bunker and

the rest to the yard.)

Only when the above checklist is gone thorough the control room

executives ask the operator to start stacker. Preceding conveyors are

started

from control room. As soon as MS-1A is started, CC-2 operator will get an

indication and will in turn start CC-2 conveyor. The operation of CC-2

conveyors and preceding conveyors and machines full under the control of

Mine-II. Pull cords/emergencies are available in machines and conveyors

sequence tripping. Interlock also exists.

The bunker filling system consists of shuttle conveyors, fixed

conveyors, crushers, disc screens and Reclaimer-A or B as the case may be.

The bunker conveyor can be started from control room in the automatic

bunker filling system. There is a provision to start the bunker conveyors and

conveyors in JT-1 manually from stage-I/or stage-II bunker. In both receiving

system and transfer system, gear box oil level, belt condition, roller

condition and any abnormal condition is to be watched continuously.

Stage-I and Stage-II bunker filling system is atomized. The

bunker conveyors can be positioned, travel taken and subsequent conveyors

can be started from LHS control room. Local operations are also possible.

Close circuit cameras are available which give comprehensive view of

different locations in the bunker, JT-1 and conveyor 14A/14B gallery.

Technicians and supervisors take care of local bunker position

monitoring. There are two streams namely A and B in Stage-I bunker bay.

Depending on the availability, one stream either A or B is selected in Stage-I

and one stream either D or C stream is selected in Stage-II, correspondingly,

for bunker filling. The first conveyor to be started is the shuttle conveyor in

the bunker. The filling sequence can be chosen depending upon the

requirement.

Subsequently conveyors in the down stream are started up to reclaimer.

After getting information regarding bunker position, the control room gives

necessary instruction to either RA/RB to stop loading. The position of the

shuttle conveyor in JT-1 are as follows.

(i) If “A” and “D” are chosen – 17A stage-I chute is

positioned and conveyor not running, 17B running and positioned

to stage-II , 17X idle and not running. (21A1A2 –20A-18A-17A-

14A) (21D1D2-20D-18D-17B-14B)

(ii) If “B” and “C” are chosen – 17A running and

positioned to stage-II, 17B idle, 17X-chute positioned and

conveyor not running. (21B1B2-20B-18B-17X-14B) (21C1C2-20C-

18C-17A-14A)

(iii) In case of emergency, 17X can be utilized

for filling Stage-I bunkers. The corresponding positions of 17X

are as follows.

Position-I 17X positioned to stage-I conveyor idle, chute only

positioned to Stage-I, B stream is running.

(21B1B2-20B-18B-17X-14B)

Position-II In case 14B is available and 18-B is out of

service, 17X can be positioned to 18A and conveyor

is run in forward direction 17A will be in idle condition

(21A1A2-20A-18A-17X). (position-II) –14B)

Position-III If 14A is available and 18B is available and 18A

is not available, 17X can be positioned in position-III

i.e. running in reverse direction. Both 17A and 17B

will be idle condition in this configuration

(21B1B2-20B-18B-17X-14A)

1.7.2. CRUSHER HOUSE

Shuttle conveyors 12A and 12B can be positioned either in 14A or

14B.    Travel can be taken either from control room or in local. 9A can be

positioned in such a way that both 10A and 11A could be by   passed and

load is directly fed to 12A. This is a newly introduced modification.

1.7.3. TT – 1 AND TT – 2

The shuttle conveyors 6A and 6B (in TT-1 and TT-2 respectively)

may be positioned to feed lignite either to 7A or 7B. The travel is possible

from control room or in local.

1.8. MAGNETIC SEPARATOR

Cross belt magnetic separators are fixed in CC-2 (MS-1A) in 7A

and 7B (MS-7A and MS-7B). There is an in line M.S. in 4A and 4B each. The

magnetic materials are separated in the magnetic separator.

1.9. METAL DETECTORS

The belt conveyor 7A and 7B are provided with metal detectors.

Once any foreign material is sensed, the system trips and a marker bag falls

into the conveyor. The location of the marker is the approximate location of

the foreign material. The unwanted material is removed manually and the

system is restored.

1.10. CONVEYOR

This is a new addition for handling lorry load. The conveyor has its tail end below the

ramp in which lorries unload the lignite. The drive head is connected to conveyor-2 and material is

stacked using stacker.

LIGNITE HANDLING SYSTEM-SPECIFICATION

CONVEYOR PARTICULARS

CapacityBelt

widthTroughing

angleBelt

SpeedConveyor

lengthMotor rating

Motor speed

UNITtonnes/

Hr.Mm Degrees m/sec. m kw rpm

CON-2 2800 1800 40 4.5 737 2X350 1500

CON-3 2800 1800 9 2.5 69 120 1500

CON-3.2 2800 1800 40 3.65 24.7 110 1500

CON-4A/B 2800 1800 40 3.59 730 420 1500

CON-6 A/B 2800 2000 15 3.65 13 37 1500

CON-7A/B 2800 1800 40 3.61 431 480 1500

CON-9A/B 2800 2400 15 2.49 6 30/37 1500

CON-12A/B 2800 2400 15 2.51 18 37 1500

CON-14A/B 2800 1800 40 3.61 344 630 1500

CON-17A/B 2800 1800 30 3.53 12 45 1500

CON-18A/B 2800 1800 40 3.57 81 160 1500

CON-20A/B 2800 1800 40 3.49 88 75 1500

21A1/A2/B1/B1 2800 1800 40 3.57 48 55 1500

CON-18C/D 2800 1800 40 3.57 93.875 160 1500

CON-20C/D 2800 1800 40 3.49 143.4 110 1500

21C1/C2/D1/D2 2800 1800 40 3.57 55.875 75 1500

10A/B 2800Disc screen &crusher

No Idler 32   37 1500

11A/B 2800Disc screen &crusher

No Idler 120/116   2x110 990

FUEL HANDLING SYSTEM OPERATION

STAGE – I

O &M MANUAL

CHAPTER – II

OIL HANDLING SYSTEM

CHAPTER – II

2. OIL HANDLING SYSTEM/STAGE – I

2.1. INTRODUCTION

Certain progress has been achieved in efforts to burn pulverized

fuel directly into a cold furnace. But the practice of cold starting with solid

fuels is yet to get established. Hence, in any pulverized fuel firing

system, oil fuel has to be utilized for initial lighting up to achieve gradual

build up of parameters over a time duration, till the furnace becomes warm

enough to sustain ignition and combustion of pulverized fuel as a continuous

reliable process.

In Neyveli Thermal Power Station – II steam generators,

provisions have been made in the furnace for firing furnace oil as well as

LSHS (Low Sulphur Heavy Stock) as Auxiliary (Secondary) fuels for initial

lighting up and to stabilize the combustion during fluctuating operating

conditions with the main (Primary) fuel i.e. Lignite. Operation of the boiler

with oil firing system is possible only upto 30 % of boiler load.

The oil fuel has number of favourable factors and hence led to its

easy adoption for the above purposes. They are as under:

1. Oil can be stored easily for long periods. The storage space

required is also less.

2. Easy transportation.

3. Easy in handling due to non requirement of equipment’s such as

conveyors, crushers etc

4. The fuel can be prepared easily for proper combustion.

Atomisation of oil fuel is more easier than pulverization of solid

fuels. The pulverizing mills etc can be avoided.

5. Easy ignition of fuel. The oil fuel can be ignited even at lower

temperatures.

6. Easier and finer control of the quantity of fuel input and hence,

the heat liberation rates in the furnace.

7. The oil fuels have comparatively high heating values and hence,

heat liberation per cubic metre of furnace volume is also high.

8. Due to high radiant heat factor of oil firing, volume of furnace is

lesser.

9. The amount of excess air required for complete combustion of

fuel is less. Thus the quantity of gases produced is also lesser.

This causes reduction in auxiliary power consumption.

10. Combustion efficiency is high. since quantity of gases produced

is less, one of the major heat losses, i.e. heat loss due to

outgoing flue gases is correspondingly reduced.

11. Absence of ash ensures clean heat transfer surfaces. There is no

need to provide elaborate ash disposal system.

12. Possibilities of ash erosion are very less. The plant also can be

maintained neatly due to the absence of ash.

13. In spite of the above advantages, it is well known that we don’t

employ it as a primary fuel due to scarce resources and high cost

due to import of crude oil raw material for the refineries.

2.2. DESCRIPTION

Oil fuels are to be handled carefully not only to achieve efficient

utilization but also to ensure safety against fire hazards and all consequent

losses. Awareness on fuel characteristics and their significance are hence

essential for operation engineers in any thermal power station.

2.3. CHARACTERISTICS OF FUEL OIL

2.3.1. DENSITY

The unit weight of liquid in kilograms per cubic metre (Kg/m3) is

the density of that liquid. This factor is reckoned for weight to volume

conversions and vice versa, and is also taken into account in design of oil

vessels, fixing of oil prices etc.

2.3.2. SPECIFIC GRAVITY

The ratio of density of any liquid to the density of water is the

specific gravity of that liquid.

2.3.3. API GRAVITY

The oil industry employees the API gravity scale, devised jointly

by the American Petroleum Institute and the National Bureau of Standards.

The relationship between the API gravity and specific gravity is an arbitrary

one shown by the formula.

Deg. API gravity = 141.5 - 131.5

Sp. Gravity at 60 0 F

2.3.4. HEATING VALUE

The heating value of a fuel of any type is the amount of heat

liberated by its complete combustion. Two different values for any fuel oil

namely gross (high) heating value and Net (low) heating value are normally

specified. The difference between the gross and the net heating value is the

latent heat of evaporation of the water vapour formed during combustion.

When determining the net heating value, the water remains in the gaseous

state and the latent heat is not recovered because the vapour is not

condensed. Variations in heating values between different fuels may be due

to any of the following factors.

1. Difference in percentage of carbon and hydrogen content

(Ultimate analysis) will cause variations, since more the

hydrogen in an oil, more is the heat it produces.

2. The type and percentage of various hydrocarbons in oil will

cause differences.

3. Sediment and particularly water decreases the heating value of a

fuel.

4. The percentage of ash in a fuel will cause some loss of heat.

5. If there is a large amount of sulphur, there will be a decrease in

the percentage of carbon and hydrogen present, with a resultant

lowering of the heating value.

6. When oxygen is present, it will combine with the hydrogen of the

fuel to form water vapour even before the secondary air or

oxygen supplied for combustion can reach the hydrogen. This

results in decreasing available hydrogen thus decreasing the

heating value.

2.3.5. VISCOSITY

The viscosity of an oil is the measure of its resistance to flow.

The viscosity is determined by the amount of time in seconds required for a

certain amount of oil at a definite temperature to flow through a

standardized orifice tube. This tube is surrounded by an oil bath, kept at the

temperature of the test. When oil is heated the viscosity decreases as the oil

thins out.

The instrument used to determine the viscosity of oil is called the

viscometer. Saybolt viscometer is usually used, having two types’ universal

and furol. The only difference between the two is the size of the opening at

the bottom of the outlet tube through which flow of the oil is to be measured.

Another instrument nowadays used is kinematics viscometer. A greater

degree of accuracy is obtained by this instrument. While running the test,

the kinematics viscometer has a constant head or height of oil, while in a

saybolt instrument; the head is not constant but decreases as the volume of

oil in the viscosity tube drains. The saybolt viscosity is reported in seconds

measured while the kinematic viscosity is report in centistokes.

Basically the methods of the testing for both saybolt and

kinematic viscosity are the same. The efflux of a certain volume of oil is

timed in seconds. The viscosity gives a good guidance for proper handling

and burning of oil.

The following difficulties are encountered with an oil of too high

viscosity.

1. Difficulty in pumping from the tank to the burner, at times it is

impossible to pump highly viscous oil.

2. If too thick and viscous, insufficient oil may reach the burners

causing erratic and spasmodic operation.

3. Flash back from the burner, as the oil comes in spurts .

4. Trouble in starting the burner due to insufficient quantity of oil

available at the burner.

5. Poor atomization. Too viscous oil will result in poor combustion.

This is chiefly due to absence of preheating or insufficient

preheating resulting in poor  atomization.

6. High viscosity oil can have more amount of carbon  residue and due

to poor combustion causes by the condition referred earlier.

Carbonization of burner tips and carbon deposit of fire chamber

walls may result.

On the other hand oil of very low viscosity results in increased

consumption of oil leading to incomplete combustion. Apart from

uneconomic operation, the furnace chamber is likely to become dirty with

soot accumulation due to heavy smoking.

Hence, for proper and efficient combustion, an oil should have a

reasonable optimum viscosity level that ensures effective atomization.

When fuels are heated, vapours are produced which may flash in

the proximity of an external flame at a certain temperature which is known

as the flash point of the oil. If the heating is continued further the

vaporization may become continuous and intense at a certain temperature to

cause a sustained burning and not just a flash. This temperature is called

the fire point.

Generally the light oils have lower flash points except in a few

cases. The flash point may also change due to the blending adopted, the

extent of refining or contamination. A flash point of 50o C to 60o C at the

preheated stage is a desirable value for any fuel oil. If oil is to be used

without preheating a flash point of 40 0 C may be accepted. On low flash

point oils, preheating should be regulated with care, since excessive heating

may give rise to the evolution of large volume of vapours within the burner

itself i.e. before the furnace, the tip of the burner nozzle.

2.3.6. POUR POINT

A disturbing feature of most oils is their ability to get into a

semisolid or solid state on cooling restraining its flow. The temperature at

which oil will just start to flow from such a state under prescribed test

conditions is referred to as the pour point of the oil. In the standard test

conducted to determine this, a specimen quantity of oil is heated and cooled.

At every interval of 5 0c temperature, the fluidity of the

oil corresponding to a temperature is noted. The pour point is taken as the

one, 5 0c above the temperature at which flow stops. The pour point is only a

guideline indicator, as what may be expected in a certain service application

of oil. When large quantities of oil are stored in

storage tanks, a very low pour point of an oil may not be a problem. Even

when the oil is at the pour point, flow of oil may not be there on a suction line

due to large amount of wax or solidified mass of oil blocking the screen or

strainer. Hence the different conditions that exist in the storage, pipe lines

etc are also the factors to be reckoned regarding the flow of oil.

To ensure satisfactory handling of oil in cold weather, a low pour

point is desirable. Oil of low pour point may also get into a semisolid or solid

state in cold weather. The conditions can be easily overcome if heating coils

are provided. Where they are not provided, air agitation can be adopted as a

means.

Problems created by low pour point are:

1. Inability of the oil to be handled by pumps.

2. Clogged strainers and lines.

3. Spitting and erratic combustion due to the interrupted and

insufficient flow of oil in a random pattern.

4. Smoking in the furnace, carbon deposits at the burners.

FUEL HANDLING SYSTEM OPERATION

STAGE – I

O &M MANUAL

CHAPTER – III

CONSTITUENTS OF FUEL OIL

AND

THEIR CHARACTERISTICS

CHAPTER – III

3. CONSTITUENTS OF FUEL OIL AND THEIR

CHARACTERISTICS

3.1. CARBON

Carbon that is present in oil or produced by it is classified under

four types.

1. The chemical compounds that are present in an oil and is

determined by chemical analysis and termed as Fixed Carbon.

2. Free carbon is the elemental carbon that has participated or has

been knocked loose from the chemical hydrocarbon due high

temperatures and pressures during the cracking of an oil. This

free carbon will be found floating and suspended within oil. The

amount of free carbon in oil is generally small and yields for

combustion and presents no problems.

3. Formation of carbon takes place on burner tips and walls of the

furnace due to the incomplete combustion of the fuel. This is

pure carbon and can be burnt away slowly when the combustion

is satisfactory.

4. Carbon residue comes under the fourth type. When oil vapour is

evolved, on heating a sample of oil, burnt under prescribed test

conditions, a certain amount of carbonaceous residue settles

down. Tests are conducted to find the value of carbon residue

related to a particular oil fuel.

When the right grade of fuel oil is used in a particular unit with proper

preheat (i.e. proper atomizing temperature) ensuring conditions of correct air

to fuel

ratio, the problem of carbon residue in combustion does not arise. However

the high carbon residue of a grade of oil or the carbon residue formed on

other conditions may present number of problems as detailed under.

1. Carbon residue that builds up on the burner tips may eventually

close the tip opening.

2. Use of wrong grade of oil can cause build up of carbon residue on

the walls of small combustion chambers, ultimately leading to

hot spots affecting the waterwalls.

3. If the preheating temperatures are too high, carbonization at the

burner tips results due to the carbon residue settling there.

Incomplete combustion oil, leakages through the burner and

flame impingement on combustion chamber walls are also some of the

causes leading to carbon deposits.

3.2. HYDROGENHydrogen is a desired element in any fuel since the heating value

of hydrogen is about 4.25 times of carbon. Hydrogen is present in the fuel in

different proportion with carbon but its percentage affects specific gravity i.

e. increasing carbon percentage reveals lowering the specific gravity. As

more hydrogen is present in any fuel more heating value is obtained.

Hydrogen mostly associated with volatile matter affects the use of fuel.

3.3. SULPHURSulphur next to Carbon and Hydrogen comes as the third

important element in an oil. Even a small percentage of Sulphur present in a

fuel oil causes number of problems. Sulphur is visually present in

combination with Carbon, Hydrogen, Oxygen or Nitrogen as different

compounds.

The most serious problem due to Sulphur is corrosion caused by

its combustion products, namely Sulphur dioxide and Sulphur trioxide in

contact with moisture affecting boiler tubes and surfaces. In the heat treating

and forging furnaces either the Sulphur gases are absorbed by the metals or

the acids react with the metals.

The more Sulphur presents in oil the less is its heating value.

3.4. WATER AND SEDIMENT

Water and sediment present in oil causes the following

difficulties.

1. Complete stoppage of operation and combustion.

2. Erratic and unsteady combustion.

3. Sparking and Spitting of the flame.

4. Flash-back of the flame.

5. Blocking and plugging of burner tips and screens.

6. Loss of heat released.

7. Erosion of burner tips and mechanical parts.

3.5. ASH

The reactions and effects of the presence of ash in oil are as

under.

1. Ash can be erosive eroding burner tips and pump parts,

valves ands delicate combustion control instruments.

2. Ash will accumulate on boiler tubes and heating surfaces,

causing a loss of heat transfer.

3. The molten ash can be absorbed into the porous refractory

surfaces. With varying loads and temperatures, it expands and

contracts, causing the refractory to spell and breakdown. This

problem is generally caused by sodium and vanadium

compounds in the ash.

At Thermal Power Station-II furnace oil of the following

specification is used.

3.6. SPECIFICATION OF FURNACE OIL – (IS:1593

QUALITY)

Carbon : 86%

Hydrogen : 11-12%

Sulphur : 4.5% by mass max.

N2 & O2 : 1% max.

Ash : 0.1%

Moisture : Traces

Density at 15o C : 0.94

Kinematic viscosity : 23 centistokes at 100o

C

Flash point : 66 – 122o C

Fire point : 132o C

Pour point : 17 – 27o C

Sediments : 0.25%

Acidity : NIL

Gross calorific value : 10,200 – 10,280

Kcal/Kg

Water content by volume ; 1%

FUEL HANDLING SYSTEM OPERATION

STAGE – I

O &M MANUAL

CHAPTER – IV

DISCRIPTION

OF

OIL HANDLING SYSTEM

CHAPTER – IV

4. DESCRIPTION OF OIL HANDLING SYSTEM

The activities of the Oil Handling System take place in the fuel

oil pump house, consisting of two sections which are commonly referred to

as

1. Decanting Pump House

2. Pressurising Pump House

The fuel oil received through lorries are transferred to the oil

storage tanks, located outside by the oil pumps in the decanting pump

house. From the above tank, oil is conveyed to the boiler operating floor of

the unit by the pumps in the pressurizing pump house.

4.1. DECANTING PUMP HOUSE

Both the sections of the fuel oil pump house are in southern side

of the boiler house. A decanting bus (300mm dia) has been erected and has

32 decanting points . Each decanting line has an isolating valve and a

flexible hose which can be connected to the lorries. Oil charged in the

decanting bus is taken through a single line (400mm dia) to the suction

header common for 4 decanting pumps inside the decanting pump house.

The decanting pumps are located at a lower elevation and there

is approximately 2.5 meters head difference between the lorry bottom and

the decanting pump suction line. This gives a positive suction for the

decanting pump, facilitating easy charging of the suction side of the pump.

The decanting pump is of 110 M3 / hr capacity and is capable of

developing a pressure of 4 Kg/Cm2 . They are of Double opposing screw type.

In the suction line of each pump there is an isolating valve, a strainer(Filter)

and a pressure gauge. The strainer has provision for steam heating. Isolating

valves are provided in the steam inlet line and condensate drain line of the

strainer. A stem trap is also provided in the condensate outlet line to

prevent steam escaping out. A drain line with a valve is provided to drain

the oil in the strainer for cleaning purpose.

To avoid any possible clogging of oil in the pump the decanting

pump has been provided with a steam jacket. Steam at 6 KSc and 210o C is

used for the above purpose. The pump has a relief valve which will open in

case of pressure rise (above 4Kg/Cm2) and diverts the oil from the delivery to

the suction side of the pump.

In the discharge side of the pump, there is a non return valve, a

hand operated isolating valve and a pressure gauge. The discharge lines of

the all four pumps join in a common discharge header (3oomm dia) through

which oil goes to the storage tanks. This line divides into 2 and each line of

300mm dia is provided with an individual isolating valve and drain

arrangements and joins at the top of the fuel oil tank. The elevation

difference between this line joining the tank and the decanting pump centre

line is 15.7 mts. All the oil lines have steam tracing provision.

4.2. FUEL OIL TANKS

Two fuel oil tanks each of storage capacity of 1900M3 are erected

inside an earthen bund, with volume equal to the storage capacities of both

the tanks put together(3800 M3). The diameter of the tank is 15 Mts. and the

height is 12.5 Mts. In the bottom of each tank, there are two water drain off

points placed diametrically opposite. Apart from them there is also a drain

provision. Suction for the fuel oil pressurizing pump is taken off from the

tank at an elevation of 0.5 Mts. from the bottom of the tank and this gives a

positive suction of 1.75 Mts. to the fuel oil pressurizing pumps.

4.3. FLOOR COIL HEATER IN FUEL OIL TANK

Since LSHS oil is being employed, the fuel oil tanks have been

provided with floor coil heaters. The floor coil heater is a steam coil heater in

which steam at 16 KSc and 230o C is supplied through tubes of 60 mm

diameter and 6.3 mm thickness. The oil can be heated upto 80o C in this

heater.

The heater is constructed in four coils with individual support.

Each coil consists of three loops and twelve loops counted from one end to

another covers almost the entire floor area of the tank. The coils are given a

slope that steam entry is at a higher elevation nearer to the centre of the

tank and condensate outlets are at a lower elevation and further from the

centre of the tank.

Steam at 16 KSc pressure and 230o C temperature is supplied

from a header through a line with isolating valves and pneumatic diaphragm

operated valve. A bypass line with isolating valve is provided for the

pneumatic

valve. This line branches off into four and each branch with its own isolating

valve supplies steam to a coil. The condensate outlets each with a steam

trap and isolation valves and bypass are connected together and taken to a

yard condensate collection tank. This tank is of 4.5 M3 capacity. Condensate

from fuel oil suction heaters and trace heating system are also fed into the

above tank. It has provisions for an overflow pipe, a drain and an air vent.

The drained condensate is allowed to go as waste.

4.4. SUCTION HEATER

At the outlet of each oil storage tank, a fuel oil suction heater is

provided. It is horizontally placed on the southern side of the tank. The oil is

heated upto 90o C before it goes to the fuel oil pressurizing pump suction.

This is a shell and tube type heater having 197 ‘U’ tubes of 19 mm

diameter(Outer) and 14 BWG thickness. Steam at 16 KSc pressure and 230o

C temperature is passed through the tubes. Oil passes through the 2607 mm

long shell of 731 mm OD and 10 mm thick.

The oil inlet and outlet of the heater are provided with isolation

valves. A bypass line with a valve is there to bypass the heater when it is

isolated. A shell drain and a channel drain are also there for draining the oil

from the heater as and when necessary.

Steam supply to suction heater is through a pneumatic

diaphragm operated valve, which is operated by a signal from a temperature

controller placed at the suction heater outlet. Isolating valves are provided

on both sides

of this pneumatic regulating valve. It has a bypass arrangement and a drain

provision also. The steam supplied gets condensed and is let out through a

steam trap with necessary isolating valves and bypass. A safety valve is

provided in the steam chest on the condensate outlet side.

The oil outlets from both suction heaters join together and go as

a single line to the fuel oil pressurizing pump house.

4.5. PRESSURISING PUMP HOUSE:

There are six screw type oil pumps in the above oil pump house.

Two pumps each forming a pair is meant for one boiler, out of which one will

be in service and the other standby.

The oil outlet from the suction heaters of both the tanks form a

single line to find its way to the above oil pump house where it forms a

header. The suction lines of the six pumps are connected to the above

header.

A filter is provided in each suction line. Two isolating valves are

provided before and as well as after the filter for isolations of the filter for

cleaning purposes. After this the two suction lines meant for a pair of pumps

of an unit are interconnected. Two more isolation valves are provided in each

suction line after the interconnection. This arrangement facilitates operation

of any of the two pumps and filters in combination thus rendering flexibility,

in the event of failure of either one of the pumps or the filters in the series.

Each filter has an air vent and a drain line.

The fuel oil pump has three screws one above the other. The

drive shaft is connected to the centre screw. The pump is capable of handling

19.4 Kilo Litres of fuel oil per hour and develops a pressure of 35 bar. A relief

valve which can be set to open at a pressure of 40 bar takes care of pressure

surges if any. A drain has been provided in the pump base to collect the

leakage oil if any. This drain is ultimately led to the common drain tank.

Two valves are provided in the delivery of each pump. Discharge

lines of two pumps of one unit join together and three such discharge lines

go towards the valve manifold cluster on the western side of the fuel oil

pressurising pump house. In the valve cluster the three discharge lines from

three pairs of pumps are interconnected by interconnecting lines each with

two valves.

With this combustion arrangement, even if both pumps meant for

one unit fail, oil supply can be maintained to this unit using a pump meant

for any other unit. A recirculation line with a non-return valve and an

isolation valve is also provided in all the three delivery lines. These

recirculation lines join the common return line from the boilers. A main valve

is provided after the above connections and then this main recirculation line

divides into two.

Each of the above is provided with three isolation valves one

inside the pump house and the other two near the oil tanks. Two recirculation

line joins the inlet of the suction heater i.e. outside the tank. The three oil

supply lines discharge lines of the pumps one each going to the units, have

been further provided with an isolating valve before they leave the pump

house. The oil lines are led to the secondary heaters at 15 metre level of the

boiler house.

Steam tracing lines are provided for the all oil lines in the pump

house. The filters and pumps are provided with steam jacketing

arrangement.

The following instruments tapping are available in the fuel oil

pressurizing pump house.

1. A suction pressure indicator in the T - joint

2. A temperature indicator in each suction point before the suction

valves.

3. A differential pressure indicator across the filter to  indicate the

condition of the filter. A differential pressure switch gives alarm

in case of high differential pressure.

4. One pressure tapping in the suction just before the pump for

indication.

5. Two more tapping before the pump for pressure switches.

4.6 DRAIN TANK AND DRAIN PUMPAll the drain lines in the fuel oil pressurizing pump house are

connected to a drain oil tank of capacity 3m3 located at 2.7 Mts. below the

floor of the pump house. A screw pump similar to fuel oil pressurizing pump,

but with a capacity to pump 2.232 tonnes per hour at a pressure of 5 bar

takes suction from the drain oil tank and pumps the oil to the fuel oil storage

tank.

The drain oil tank has an inlet line with two valves. A level

indicator, a man hole, a drain and an air vent are provided in the tank. The

tank has steam heating provision. In the suction line of the pump a steam

jacketed filter is provided with two isolation valves before it. The discharge

lines of the pump has a non return valve and two isolating valves. It then

divides into two and joins the two fuel oil storage tanks.

FUEL HANDLING SYSTEM OPERATION

STAGE – I

O &M MANUAL

CHAPTER – V

TECHNICAL DATA

OF

PROCESS EQUIPMENTS & ACCESSORIES

CHAPTER – V

5. TECHNICAL DATA OF PROCESS EQUIPMENTS &

ACCESSORIES

5.1 DECANTING PUMP SUCTION STRAINER

Number of strainers : Four

Type : Simplex type

Flow rate : 110 M3 /hr

Operating pressure : 0.5 Kg/Cm2

Operating Temperature : 80o C

Design Pressure : 6 Kg/Cm2

Design Temperature. : 230o C

Viscosity at Operating : 750 CentipoiseTemperature

Specific gravity at operating Temp. : 0.92Max. Permissible pressure drop across

Strainer : 0.1 Kg/Cm2

Body material : Cast Steel ASTM A216-

WCB

Screen/basket material : Stainless Steel AISI  410

Hydrostatic test pressure, Shell side : 10 Kg/Cm2

Hydrostatic test Jacket side : 6 Kg/Cm2

Jacketing steam pressure : 3 to 4 Kg/Cm2 &

& Temperature 210o C

Gasket Material : Asbestos.

5.2. DECANTING PUMPNumber of pumps : Four

Type : Double Screw opposing type

Capacity : 110 M3/hr

Pressure : 4 Kg/Cm2

Design Velocity : 1000 CST

Max Permissible suction lift : 5.5 MLC

Flow temperature : 30o C

Make : TUSHACO pumps, India.

Jacketing steam : 6 Kg/ Cm2, 210o C.

5.2.1. DRIVE MOTORType : AMW 2255 4H 1

Voltage : 3 Phase, 415 Volts

Power : 37 KW

Speed : 1480 Rpm

Current : 63.5 Amps

Make : NGEF, India.

5.3. FUEL OIL STORAGE TANKSNumber of tanks : Two

Capacity : 1900 M3

Diameter : 15 M

Height : 12.5 M

Number of tanks : One

Capacity : 100 M3

Diameter : 5.0 M

Height : 5.4 M

5.4. FLOOR COIL HEATERNumber of Heaters : Two

Location : Storage tank bottom

Number of coils : Four

Number of loops per coil : Three

Heating Steam : 16 Kg/ Cm2, 230o C.

Oil temperature at outlet : 75-80o C.

5.5. FUEL OIL SUCTION HEATERNumber of Heaters : Two

Type : Shell & Tube type

5.5.1. SHELL SIDEShell size : Dia 731 x 10 x 2607 mm

Medium in Shell : Fuel oil

Design Pressure : 1.5 Kg/Cm2

Design Temperature. : 60o C

Hydrostatic test pressure : 2.25 Kg/Cm2

Number of passes : One

5.5.2. TUBE SIDENumber of tube : 197

Size of the tube : Dia 19 mm x 14 BWG

Number of passes : Two

Medium in tubes : Steam

Heating Steam : 16 Kg/ Cm2, 230o C.

Heat transfer area : 28.7 M2

Hydrostatic test pressure : 22.5 Kg/Cm2

5.6. FUEL OIL SUCTION FILTERS

Number of filters : Six

Type : BOLL & MECH filter bars

Flow rate : 5.6 Kg /Sec

Working pressure : 10 bar

Working Temperature : 80o C

Max. allowable pressure drop : 0.07 bar – Clean condition

0.2 bar – 50% choked condition.

Jacketing steam : 6 Kg/Cm2 & 210o C

5.7. FUEL OIL PRESSURISING PUMP

Number of pumps : Six

Type : SMH 440 R40 E6-S Screw

Pump

Make : All Weiler, AG, Germany

Capacity : 295-340 Litres/Min.

Delivery Pressure : 35 bar

Viscosity : 16-850 mm2/Sec

Speed : 1450 Rpm

Direction of rotation : Clockwise viewing from

Motor.

Max Permissible suction lift : 2.5 M 16 mm2/Sec

(For Min NPSH required) 4.0 M 380 mm2/Sec

5.5 M 850 mm2/Sec

5.8. DRIVE MOTOR:

Type : 11A4 G220-4AA 907- 22553

Voltage : 3 Phase, 415 Volts

Power : 35.5 KW

Speed : 1470 Rpm

Current : 64 Amps

Make : Siemens, Germany.

5.9. DRAIN OIL TANK

Number of tanks : Four One in FOPH

: One in each Boiler at 0M

Capacity : 3 M3

Diameter : 1.25 M

Length : 2.74 M

Operating Temperature : 130o C

Test Pressure : 2 Bar

Heater Type : Turn loop Steam heater

Heater Size : Dia 42.2 x 3.6 x 1.34 m2

Make : Wezel,GmbH,Germany

5.10. FILTER BEFORE DRAIN PUMP

Number of filters : Four, One in FOPH

One in each Boiler at 0M

Make : BOLL & Kirch filter bars,

Gmbh,

Germany

Type : Simplex

Working pressure : 10 bar

Working Temperature : 80o C

Volume : 11.5 dm3

Max. allowable pressure drop : 0.07 bar – Clean

condition

0.2 bar – 50% choked condn.

Jacketing steam : 6 Kg/Cm2 & 210o C

5.11. DRAIN OIL PUMPNumber of pumps : Four, One in FOPH

One in each Boiler at ‘0’ ML

Type : SNH 40 R4 6DS-GG Screw

Pump

Make : All Weiler, AG, Germany

Capacity : 40 Litres/Min.

Pressure : 3 to 4 bar

Viscosity : 16-350-850 mm2/Sec

Speed : 1450 Rpm

Max Permissible suction lift : 2.5 M 16 mm2/Sec

(For Min NPSH required) : 4.0 M 350 mm2/Sec

: 5.5 M 850 mm2/Sec

5.11.1. DRIVE MOTORVoltage : 3 Phase, 415 Volts

Power : 1.1 KW

Speed : 1450 Rpm

5.11.2. FUEL OIL SYSTEMOil Temperature : 50 to 90o C

Oil Pressure after Pump : 34 bar

FUEL HANDLING SYSTEM OPERATION

STAGE – I

O &M MANUAL

CHAPTER – VI

FUEL OIL FILTERS

AND

FUEL OIL PRESSURISING PUMP

CHAPTER - VI

6. FUEL OIL FILTERS

Parameters Suction Pressure oil

Drain Oil

Filter Filter

Filter

1. Oil Flow, Kg/Sec 5.6 5.37 0.61

2. Operating Pressure, bar 5 38 5

3. Operating Temperature, o C 80 130 80

4. Pressure drop for clean oil, 0.07 0.1 0.07bar

5. Pressure drop for 50% 0.2 0.22 0.2Contamination, bar

6. Filter diameter, mm 0.5 0.3 0.5

7. Filter Surface, M2 11762 7563 2330

8. Test Pressure, bar 35 52 15

Note: The permissible value of resistance across the filter is 0.8 bar. If

this value increases the filter must be cleaned. Resistance of the filter will

be checked wice in a shift. It the pressure drop of the filter rapidly increases,

this is the indication of contamination of oil system. When the pressure drop

falls suddenly, the filter is broken through.

6.1. PUTTING THE FILTER IN TO SERVICE

1. The pre heating steam for filters steam jacket is to be admitted for

warming up the filter.

2. After warming up, ensure closing of the drain.

3. The air vent of the filter should be opened.

4. Oil is to be admitted to the filter slowly by slightly opening the inlet

valve.

5. When oil starts coming out in the air vent the air vent should be

closed. Now the filter is in charged condition.

6. Inlet and outlet valves can now be opened fully.

6.2. FILTER CLEANING PROCEDUREWhen a filter becomes contaminated, the following procedure

must be followed.

1. The spare filter should be put into operation.

2. The inlet and outlet valves of the choked filter will have to be

closed.

3. The drain of that filter should be opened and any locked up

pressurised oil is to be released.

4. The heating stem system will have to be shut off.

5. The filter is to be removed and the filter is to be taken out and

cleaned (while cleaning the filter the cleaning medium should be

blown through from the “clean side” of the filter).

6. The cleaned filter unit should then be placed inside the filter

housing. After checking that the seals are good, the lid can be

placed keeping the air vent valve open.

7. The drain valve of the filter should be closed.

8. The heating up steam system can be put in operation and the filter

can be taken into service.

6.3. STARTING OF PRESSURISING OIL PUMPS

1. Ensure power supply and control supply to the pump.

2. The oil pipings and filter should be heated upto 50o C using trace

heating steam.

3. The fuel oil pressurising pump is also heated up slowly.

4. The oil pipings and filter should be charged up to the pump through

the suction side.

5. Both the valves on the suction side and the valves on the delivery

side of the pump are to be opened. It should be ensured that the

NRV on the delivery side is tight (when another pump is already

in operation)

6. The recirculation valve at the fuel oil pressurising pump house must

be kept opened, when oil is not taken to the boiler house.

7. The pump should be started and the discharge pressure is to be set

at 35 bar adjusting the recirculation valve.

6.4. STOPPING OF THE FUEL OIL PRESSURISING PUMP

1. The spare pump should be prepared and started.

2. The running pump is to be stopped and its delivery valve should

be closed.

3. If the pump is to be drained, the suction valve is to be closed and

the pressure is to be released.

4. The trace heating system of the pump should be isolated.

6.5. COMMISSIONING OF FUEL OIL PRESSURISING

PUMPS – OIL LINES

When all the pumps in the fuel oil pressurising pump house are

not working, the auxiliary system are also out of operation, the system will

have to be put into operation in the following sequence.

1. The trace heating system at the oil delivery line of the

boiler, to which oil is to be supplied, should be commissioned.

2. Ensure the power and control supply for oil system and steam

systems of the boiler.

3. The steam systems (a) auxiliary heating steam supply at 16

bar and (b) trace heating steam supply at 6 bar are to

be commissioned.

4. The fuel oil in the storage tanks should be heated up to at  least

75oC . The temperature of oil in the tank should not be  raised

above 80o C.

5. All the instrument lines connected to the oil system are to

be made ready and trace heating of these lines are also to

be  arranged.

6. The operation of the interlocks and protections of the

system should be checked in test condition.

7. The drain oil system in the fuel oil pressurising pump house

as well as in the boiler are to be kept ready.

8. First the oil lines up to filters are charged from the tank.

Then filters are charged and after that pump is charged.

9. Now the pump can be started as per the standard procedure.

10. Pressure should be decreased to 10 bar on the discharge side by

opening the recirculation valve at pressurising pump house.

11. The oil lines upto boiler house is then charge by slowly opening

the delivery valve in the oil line at pressurising pump house.

12. The manual regulation valve in the recirculation line before

secondary oil preheater is to be opened to put the oil

in  recirculation. Now the recirculation valve at

pressurising pump house can be closed.

13. The pressure in the oil piping shall be set to 20 – 22 bar

by adjusting the manual recirculation valve.

14. The pneumatically operated regulation valve can then be put into

operation after opening the isolation valves before and after that.

15. Valve PCV can be switched into automatic mode of operation and

the manual regulation valve shall now be closed.

The fuel oil system up to secondary heaters is now commissioned

and the oil will be under recirculation through the recirculation line before

secondary heaters.

6.6. ROUTINE CHECKS AND PRECAUTIONS DURING

NORMAL OPERATION

1. Screw pump should be started with the discharge valve in closed

condition in order to avoid a very fast pick up in the delivery

pressure and overloading of pumps.

2. Screw pump should be started only when it is completely

filled with oil. Dry operation results in the damage of the pump.

3. Temperature of the oil system should be in the range

between 50oC and 80oC.

4. Operation of each and every equipment in the pump

house should be checked at least twice in a shift.

5. The tightness of the piping will have to be inspected once in

a day.

6. The pressure difference across the filter should be checked.

If and when the pressure difference is near 0.8 bar the

filter should be cleaned.

7. Tightness of the stiffing boxes of the amatures should be

observed regularly and if necessary tightened then and there.

8. The manometers should be tested once in a month regarding the

cleanliness of the impulse lines etc.

9. Storage tanks should not be filled more than 95%. Level of

the tanks should be closely monitored.

10. It is forbidden to close both ends of any part of an oil

piping without drainage, since the oil pressure may get increased

by the trace heating system to a dangerous high value.

6.7. DECOMMISSIONING OF THE OIL SYSTEM

The oil system normally serves as a reserve in case of any load

fluctuations or flame pulsations during the regular operation of the boiler.

So, the complete oil system is decommissioned only in rare occasions.

In case, the oil piping or the connected filter and pump have to

be stopped for the purpose of any repair, then the remaining pipes and

equipments should remain filled up with the oil and the trace heating system

should also be kept in operation.

6.8. EMPTYING THE OIL PIPES

The oil lines may have to be emptied incase of a long break in

the operation or repairing of the oil-pipes. During such condition the

following procedure is to be adopted.

1. The drain oil tank should be emptied and made ready

for receiving the oil.

2. The trace heating system of the drain pipings should be put into

operation.

3. The pipe-stretch to be drained is to be isolated and pressure is to

be released. The emptying can be commenced immediately.

4. When the pipe drain the trace heating system for that

piping should be shut off.

5. If the oil pipe is to be disconnected for repairs, then after

draining the pipe, the pipe should be blown out by steam. Only

after such blowing out, the trace heating system is to be shut off.

NOTE

1. A part of the pipe which is to be blown should be connected to

one end of a stem hose, the other end steam hose should be

connected to the trace heating pipe. Blowing steam should be

taken away from the place of emptying.

2. Blowing shall be done until no oil is brought out by the steam.

3. The blowing off hose should be handled with utmost care. Since it

has no insulation and could cause dangerous accidents.

6.9. TROUBLE SHOOTING

SL. NO

TROUBLE POSSIBLE CAUSES REMEDY

1. The pump does not produce the design pressure

(a) The relief valve may be untight causing recirculation of oil back into the suction pipe.

(b) Any outlet valve or drain valve in the delivery side of the pump may be either in opened condition or passing.

(c) Insufficient pressure on the suction side.

(d) The oil may be too warm

(e) Flap valve of the spare pump may

have passing.

(f) Excess wearing out of the

pump rotor.

(a) The relief valve should be adjusted or repaired.

(b) The valves should be checked and closed tightly, passing valves should be attended at the earliest opportunity.

(c) Filter on the suction side should be checked and all the valves in the suction side should also be checked for full opening.

(d) oil temperature should be reduced below 80o C.

(e) Flap valve should be repaired.

(f) The rotor should be replaced by new one.

2 Oil is solidified in the oil pipe

(a) The steam traps in the trace heating system may be in choked condition.

(b) Low steam pressure in the tracing steam system

(a) The steam trap should be checked and adjusted.

(b) Steam pressure and temperature should be adjusted to the rated values.

3 Oil leaks from the oil system into the environment. The oil may mix up with water in the sewage canal

Leaks, if any in the system The oil must be collected and removed in the shortest possible time. It is forbidden to wash up the drip oil with petrol or other inflammable substance. Instead of them ,hot water or steam should be used for the removal of the oil.

4 Pressure in the oil system varies.

(a) The shut off device of any valve may become loose and swinging in.

(b) Water may enter into the oil system.

(a) If unusual sound is observed in any of the valves, it is to be opened fully. Otherwise it should be closed and repaired.

(b) The water should be drained at the deep points of the system. If

possible the water can be heated out of the system.

5Level of the oil tank is rapidly increasing or overflow occurs

(a) Any one of the valves in the pressurised oil pipe lines connected to the tank may be in opened condition.

(b) A large amount of water may get into the tank or any heating pipe coil punctures may also cause level rise

and oil in the tank may become foamy.

(a) Any such opening of valve should be located and closed.

(b) The heating steam coils should be closed one by one to locate the puncture if any. The punctured coil should be isolated immediately.

6.10. MEASURE OF SAFETY PRECAUTIONS FOR

ACCIDENT - PREVENTION

1. It is forbidden to store any inflammable substances or objects,

which are not relevant with operation and maintenance of

oil supply, in the oil supplying system.

2. Draining of the oil from the oil system into open air or rain-water

canal and sewage channel is forbidden, similarly blowing out

pipes into the above places.

3. Use of naked flame in the oil supply rooms and its

surroundings  is forbidden.

4. A 0.25M3 vessel fully filled with dry sand along with a spreader

should be kept in every room.

5. Necessary number of fire extinguishers should be kept in that

area.

6. A fire fighting system incorporated in this area should be checked

for its readiness.

7. It is forbidden to warm up solidified oil by means of a

naked flame.

8. Before doing any repair in the oil system the pressure must be

released from the piping system and from the equipment, then

they shall be drained and blown with steam.

9. During repair the fire-fighting regulation must be

strictly complied with.

10. Rules for works to be done in oily rooms with poor ventilation or

in tanks.

The work should be done only be healthy workers.

The worker should have been properly trained in the work.

Oxygen respirator or a mask provided with an air pipe

should be provided.

Worker doing the job must be changed periodically.

Rescue facilities should be kept ready.

Tank inside welding should be done only on special class I

safety permission observing all necessary precautions.

FUEL HANDLING SYSTEM OPERATION

STAGE – II

O &M MANUAL

CHAPTER – VII

FUEL OIL FILTERS

AND

FUEL OIL PRESSURISING PUMP

CHAPTER - 7

7. FUEL OIL HANDLING SYSTEM/STAGE – II/LDO & FO

7.1. INTRODUCTION

Acute energy crisis eventually makes enormous trust on efforts

to invent an apt engineering for better utilization of raw materials available

in abundance viz. Coal. Attempts are in progress vigorously to discover

suitable techniques to burn coal directly in the coal furnace. As a result the

fuel oil firing system becomes adherent in the coal based power station. It

has become a practice to increase the capacity of oil firing system, beyond

that required for coal ignition to a capacity that enables the turbine to be

synchronized on fuel oil alone, as the size of the steam generators has grown

up. Fuel oil firing system indeed provides a moderate amount of

replacement of generating capacity in the event that an excessive number of

pulverizers are out of service due to unforeseen circumstances.

An elaborate facility has generally been installed in the power

station known as oil handling system, which should be designed to fulfill the

following basic requirements.

1. Quick and reliable decanting ability, whenever fuel oil has been

brought to site.

2. Safe and enough storage capacity of fuel oil.

3. Continuos pre heating facility for the fuel oil to a temperature, so

that fuel oil flows to the pressurizing pumps by gravity.

4. Maintaining desired fuel oil viscosity at constant value, so that

the real measurement of fuel oil flow ensures, not only efficient

atomization of fuel oil in the furnace, but also ensures correct air

fuel ratio for its complete combustion in the furnace and

5. Raising of fuel oil pressure so as to achieve proper atomisation

over a specified load range.

The fuel oil namely light diesel oil and furnace oil are the two

entities in the oil firing system of stage-II steam generators. A separate fuel

oil pump house fort Stage –II has been installed behind the stage-II water

treatment plant to handle both fuel oils.

7.2. FUEL OILS

Fuel oil is rather a complex hydrocarbon mixture containing

traces of sodium, calcium, magnesium, manganese, aluminium, vanadium,

nickel, copper, silica, iron, nitrogen and Organo metallic components, in

various forms through small percentages. Residual fuel oils are largely by

products of refinery operation and they are un-vapourised portion of

petroleum crude during the process of distillation. In India, residual fuel oils

are commonly known as furnace oil, conforming to medium viscosity grade-II

of IS specification 1593/83.

Diesel fuel oil is a fuel suitable for burning in diesel or

compression ignition engines. Two main diesel fuels oils are marketed in

India – High speed diesel oil & Light diesel oil. The later is a blend distillate

fuel with small proportion of residual fuel oil and it is found most suitable fuel

oil in the coal fired steam generators during start up. Both are marketed

confirming to Bureau of Indian Standards specifications 1460-1974.

The basic properties and constituents of the fuel oils being used

in stage-II steam generators are detailed as under.

FO LDO

Carbon residue % by weight : - 1.5

Total Sulphur, % by weight : 4.5 1.8

Ash, % by weight : 0.1 0.02

Water Content, % by Volume : Traces 0.25

Density, g/ml : 0.94 at 25oC 0. 88-92 at 75o C

Kinematic viscosity centistokes : 23at 100o C 2.5 – 1.57 at 38o C

Flash point, o C : 66 - 122 66

Fire point, o C : 132 130

Pour point, o C : 17 – 27 12 - 18

Sediments, % by weight : 0.25 0.1

Gross calorific value, Kcal/Kg : 10,200 – 10,280 10,000

7.3. LDO SYSTEM

7.3.1. LDO DECANTING

LDO is usually brought to site through oil tankers. They can be

connected to a decanting bus, laid in the southern side of stage – II fuel oil

pump house. It is having four decanting points and an air vent. The

decanting point, is nothing but a pipe with a hand operated isolation valve

and a flexible hose which are used for decanting operation. The decanting

bus carries oil to a common suction header by gravity which is located inside

the pump house. One air vent and a drain line are provided in the suction

header for smooth transferring operation of fuel oil from the tanker.

Two branches are emanating from the suction header and in

each branch there is an oil filter and a light oil transfer pump.

The oil filter is of simplex type having a screen with 250 microns

perforations. It enables trouble free pumping by separating foreign materials

present in the oil. The accumulation of contaminants in the oil filter can be

monitored with the help of

1. Differential pressure colour indicator and

2. Differential pressure indicator.

The normal colour/differential pressure is white/< 0.05 bar

respectively. When the filter gets clogged (50% clogging) the

colour/differential pressure will be red/>0.25 bar respectively. Isolation of

that filter can be done using hand operated valves provided on either side.

Draining and recharging the filter can be carried out, with the help of an air

vent and a drain provided at the top and bottom of the filter respectively.

Out of two LDO transfer pumps, normally one will be taken into

service and the other will be in standby. Each LDO transfer pump is located

after the corresponding filter unit. It is a screw type pump capable of

delivering 225 Lpm at a pressure of 4.5 Kg/Cm2. Each pump is driven by an

induction motor of rating 3 phase,415 V, 5.5 KW, 1430 Rpm & 11 Amps. In

order to monitor adequate oil flow to and away from the pump, pressure

indicators are provided at the suction and discharge side of the pump. A non

return valve and a hand operated discharge valve are installed at the

discharge side of each pump. These delivery lines are joined together and a

single delivery line carries oil towards LDO storage tanks. A drain is provided

in the common delivery line.

Two LDO storage tanks are installed in the eastern side of the

fuel oil pump house/ Stage – II. Each tank is of 5.0 M diameter and 6 M

height and is capable of storing 100 M3 of oil. The LDO delivery line from LDO

transfer pumps is branched into two lines near the tank and each one is

connected to the LDO storage tank at a higher elevation. A breather is

provided at the top of each tank. In order to ascertain oil level, a level

indicator, a level switch and afloat level indicator are provided in the tank. An

artificial bund (dykes) has been built around the tanks, with a holding

capacity of 200 M3 which is equal to the total capacities of both tanks. This

facility not only contains the oil of any oil leak/tank burst, but also enables

easy extinguishing of fire.

7.3.2. LDO SUPPLY TO BOILERS

LDO flows out from the LDO storage tank through a line in which

a hand operated isolation valve is provided. The LDO suction lines emanating

from two tanks are joined to form a single line near the LDO tank area. It is

extended to the pump house, where it is divided into two branches. In each

line a filter and a light oil pressurising pump are installed. Normally out of

two filters and two pumps any one filter and any one pump can be taken into

service. A drain is provided before the filters. It is used in case of doing any

maintenance in the LDO suction line.

The LDO suction filters are of simplex type having screen with 0.

5 mm perforations, to separate any solid contaminants in the oil. The

clogging of the filter can be found out, by checking pressure drop across the

oil filter for which a differential pressure, colour indicator and a differential

pressure

indicator and are installed across each filter. In order to drain as well as

charge the filter, an air vent and a drain are provided at the top and bottom

of the filter respectively. A tray is provided below the filter to collect drained

oil, which can be admitted to the drain oil line. A hand operated isolation

valve is provided, on either side of the filter for isolation purpose.

A line connects the outlet of both filters after their outlet valves

known as interconnection line. It is mainly used to connect any filter to any

pump so that without stopping running pump, reserve filter can be brought

into service. A branch is taken from the middle of the interconnection line to

oil scheme for flushing operation. In addition a drain is provided in this

interconnection line.

LDO pressurizing pumps are screw type pumps (SNH 120 ER 46 D

6.9 W12) having a capacity to discharge oil at the rate of 185 litres per

minute (11.1 Kl/hr.) and at a pressure of 35 bar. An in built relief

valve is provided in each screw pump, which is set to open, when the

delivery pressure is more than 35 bar. But it can be adjusted to a maximum

of 38 bar. The pump is driven by a motor of rating 3 phase, 415 volt, 18.5

Kw, 2940 rpm, 33 amps. A hand operated valve and a pressure indicator are

provided on either side of the pump. A NRV is installed before the pump

discharge valve. The discharge lines of the pumps are connected as a single

delivery line, carrying light diesel oil to the boiler area.

7.3.3. LDO RECIRCULATION LINE

A recirculation line is taken from the LDO delivery line in the

pump house. This is mainly intended to maintain required pressure

(25Kg/Cm2 ) in the delivery line and also to safeguard the delivery line in

case of undue pressure rise, due to non-utilization of LDO in the boilers, when

the LDO pump is in service. A pneumatically operated diaphragm type

pressure control valve is provided in this re-circulation line. Hand operated

isolation valves are provided at inlet and outlet of the control valve. A

bypass line with a hand operated valve is laid for this control valve. After

this arrangement a NRV is provided in the common line.

One pressure indicator, one pressure switch and one pressure

transmitter are provided in the LDO supply line to boilers. The pressure

transmitter will give necessary signal to the pressure control valve whenever

LDO pressure get varied. Indeed, the recirculation line diverts unused oil

back to the LDO tank. The re-circulation line extends to the storage tank

area, where it branches into two and each line is connected to the tank at a

higher elevation.

NOTE

LDO pressurising pump will not be in service normally. It will be

started as and when it is required.

FUEL HANDLING SYSTEM OPERATION

STAGE – II

O &M MANUAL

CHAPTER – VIII

FURNACE OIL SYSTEMS

CHAPTER - VIII

8. FURNACE OIL SYSTEMS

8.1. FURNACE OIL DECANTING

Furnace oil decanting and storage system, available in stage-I

fuel oil pump house. It is common for all seven boilers in TPS-II. But stage-II

fuel oil pump house facilitates pumping of furnace oil to stage-II boilers after

pre-heating. This heating facility ensures free flow of furnace oil from the

tanks to stage-II fuel oil pump house by gravity.

Furnace oil for stage-II boilers is taken from each tank through a

separate suction line. But this is located just opposite to that taken for

stage-I boilers in the same tank. In each suction line, there is a primary

heater known as suction heater, flanked by hand operated isolation valves.

8.2. SUCTION HEATER

Suction heater is a “U” type, hair pin type, oil on shell side

condensing type heater . It is having 197 ‘U’ tubes of 19 mm

diameter(Outer) and 14 BWG thickness. Steam flows through the tubes

where as, oil flows outside the tubes (i.e. inside the shell of 731 mm OD and

10 mm thick. The steam at 16 KSc pressure and 230o C temperature is

passed through the tubes through a pneumatically operated diaphragm type

control valve (TCV) which is operated by a signal from the temperature

switch mounted in the FO line carrying oil to the stage-II FOPH. Oil passes

through the 2607 mm long shell of 731 mm OD and 10 mm thick.

The oil inlet and outlet of the heater are provided with isolation

valves. A bypass line with a valve is there to bypass the heater, when it is

isolated. A shell drain and a channel drain are also there for draining the oil

from the heater as and when necessary.

Steam supply to suction heater is through a pneumatic

diaphragm operated valve, which is operated, by a signal from a temperature

controller, placed at the suction heater outlet. Isolating valves are provided

on both sides of this pneumatic regulating valve. It has a bypass

arrangement and a drain provision also. The steam supplied gets condensed

and is let out through a steam trap with necessary isolating valves and

bypass. A safety valve is provided in the steam chest of suction heater.

A bypass line to the suction heater from each tank, with a hand

operated valve is also taken and connected together with heater outlet line

to form a common outlet line. This line is used to draw oil whenever suction

heater is under maintenance. The oil outlets from both suction heaters join

together and go as a single line to the fuel oil pressurising pump house.

Trace heating system is laid, through-out the oil system for which

steam is obtained from a pressure reducing station 17 bar/10 bar. Auxiliary

steam tapped from the interconnection header, near unit-IV supplies steam

to this 17/10 PRS located inside the fuel oil pump house.

8.3. OIL PRESSURISING PUMPS

Oil line from oil tanks form a common suction header for two pair

of oil pressurizing pumps. One pair is meant for boilers 4 & 5 and the other

pair for the boiler 6 & 7. Arrangement in both streams are very similar. For

a pair of pump, two separate lines are taken from the suction header. In

each line there is a filter and pump. The filters are of simplex type 6”-150

lbs-RF having perforations of 500 microns. On either side of the pump and

filter, hand operated isolation valves are provided. An interconnection line is

provided in between the pump and filter connecting both lines of that pair. A

NRV is also provided in the discharge side of the pump. This interconnection

permits the use of any filter for any pump of that pair.

Each pressurizing pump is capable of delivering oil at the rate of

500 lpm at a pressure of 35 bar. The pump is driven by a motor, of three

phase, 415 Volt, 45Kw, 1478 rpm, 82 amps. The following instruments are

provided in the oil scheme.

1. Pressure and temperature before the filter.

2. Differential pressure indicator across the filter.

3. Pressure switch and pressure indicator before the pump.

4. Pressure indicator and pressure switch after the pump.

5. Temperature indicator after the pump.

The LDO line emanating from the interconnecting line after LDO

filters, is branched into two lines. Each line with a hand operated valve is

connected to the interconnection line provided after oil filters. This is

provided in both streams.

The discharge lines from the FO oil pumps of the pair, are

connected to form a single delivery line. This line feeds FO to oil preheating

station otherwise known as secondary oil preheating station. A re-circulation

line is taken, before the secondary oil heating station in each stream. A

pneumatically operated diaphragm valve is provided along with hand

operated isolation valves on either side in the re-circulation line. A line with

a hand operated valve is provided as a bypass for this diaphragm valve. A

NRV is also there in the re-circulation valve after the bypass line connection.

The re-circulation lines of both streams are connected to the return oil line

from the boilers and finally diverted to oil tanks.

8.4. SECONDARY HEATERS

There are two secondary oil preheaters in each stream, out of

which one will be in service, the other stand by. The pumped oil is preheated

from 85oC to 130oC in the secondary oil preheaters so that

1. Power required to pump oil becomes less.

2. Viscosity of oil gets reduced for better atomization

and combustion.

Two oil preheaters are arranged in parallel and located one over

the other. The heater is shell and tube type, consisting of 224 tubes of

diameter 20mm placed in a shell of diameter of 559mm. The heater is of six

pass design. Oil flows through the straight tubes of the heater and is heated

to 130oC by steam supplied to the shell portion around. A hand operated

valve is provided at the inlet and outlet of each heater in order to isolate the

heater as and when it is needed. One safety relief valve is provided at the oil

side of each heater. An air vent and drain line are provided in the oil side of

the heater.

Steam is drawn from steam line taken from the auxiliary steam

interconnecting bus. This steam is normally supplied to any one of the

heater. In this line there is a Y type strainer and a pneumatic diaphragm

control valve, flanked with hand operated valves. A bypass line with a valve

is also provided for this. After this the steam line is branched off into two

and each line with a hand operated isolating valve is connected to top of one

heater. A safety valve is installed in each branch to safeguard the shell

against undue pressure rise.

When the heater is in service, the steam heats oil and gets

condensed and it is collected through a drain line having a steam trap. Hand

operated valves are provided on either side of the steam trap. A bypass with

a valve is provided for the steam trap line. A NRV is also located in the drain

line after bypass line connection. The condensate line of both heaters are

taken to yard condensate tank.

The oil outlet lines from both heaters are connected to form

single delivery line carrying oil to boiler area. The following instruments are

installed in the re-circulation and heater zone.

1. Pressure switch after the heater.

2. Temperature switches after the heater.

3. Temperature indicator and temperature element after

the heater.

4. Auxiliary steam pressure indicator before the TCV

5. Auxiliary steam pressure indicator after the TCV

6. Auxiliary steam temperature indicator before the TCV

7. Auxiliary steam temperature indicator after the TCV

The oil line from one pair of oil heaters carries preheated to

boiler 4 & 5 and the line from other pair of heaters to boiler 6 & 7. the return

oil lines from all the boilers are connected together and a single line carries

return oil back to Stage – II fuel oil pump house. This return oil line is

connected to the recirculation lines of both streams and finally taken to the

oil tanks area, where the oil can be admitted at the inlet of any of the suction

heaters or to any one of oil tanks. Hand operated valves are provided

suitably for the above purpose.

8.5. DRAIN OIL SYSTEM

Oil drains are provided at various places in the LDO system and

FO oil system in order to drain oil from oil lines in case of necessity for

maintenance. The drained oil from oil lines is diverted to a drain oil tank.

Totally there are five drain oil tanks for stage – II out of which one is located

in stage – II fuel oil pump house. Remaining four are provided at the boiler at

the rate of one per boiler.

The drain oil tank in FOPH is located at - 6.4 ML in the floor of

the pump hose to help effective draining of oil from the lines. All drains

emanating from the oil system at FOPH join a common drain line and this line

with a valve is connected to the drain oil tank. The capacity of drain oil tank

is 1 M3. The tank is of size Dia 1000 mm x 1550 mm. Provision for steam

heating is available to maintain fluidity of oil while it is stored in the steam

pipe of Dia 48..3 x 3.7 mm with an heating area of 0.8 M2 is fitted inside the

tank for this purpose. The tank is fitted with a level indicator, two level

switches, a man hole, a drain and an air vent.

A drain oil pump is provided to pump the oil back to main tanks.

In the suction of the pump a filter is provided. Isolation valves are provided in

the suction side of the filter discharge side of the pump and also a NRV in the

discharge side of the pump. The drain oil pump has a capacity to deliver the

oil at the rate of 39 Lpm and at a pressure of 4.9 bar which is driven by a

motor of rating 3 phase, 415 V, 1.1 KW, 1415 Rpm, 2.65 Amps.

The discharge line from the pump joins the recirculation line

originating from the secondary heaters which in turn is connected to storage

tanks.

FUEL HANDLING SYSTEM OPERATION

STAGE – II

O &M MANUAL

CHAPTER – IX

OPERATION OF

LDO SYSTEM

CHAPTER - IX

9. OPERATION OF LDO SYSTEM

9.1. DECANTING OF LDO

1. Check that no line clear (LC) or Safety Permit is pending on the

LDO decanting system.

2. Ensure that all drains in the LDO system are closed.

3. Select the oil tank to which oil is to be transferred.

4. Note down the initial oil level in the tank.

5. Open the oil supply valve to the tank and ensure that oil supply

valve to the other tank is closed.

6. Ensure that valves of the filter and pumps are closed.

7. Ensure that all valves in decanting points are closed.

8. Open the air vent in the decanting bus.

9. Connect LDO bousers to the decanting bus through flexible

hoses.

10. Open decanting valve partially.

11. Close the air vent as soon as oil flows out from decanting bus.

12. Open decanting valves fully.

13. Select any one filter and pump.

14. Charge the filter.

15. Open discharge valve of the pump.

16. Start the pump.

17. Check the motor and pump for any vibration, abnormal

noise, spark etc.

18. As soon as the lorry is emptied stop the pump.

19. Close the discharge valve of the pump.

20. Close oil supply valve to the pump.

21. Close all decanting valves and disconnect bousers.

22. Measure final oil level in the tank.

9.2. OPERATION OF LDO SUCTION FILTER

1. Check the pressure drop across the filter which is in service.

2. If the pressure drop exceeds 0.22 bar, the standby pump and

filter is to be started.

3. Stop the running pump.

4. Close discharge valve of the pump.

5. Close hand operated isolating valves of the clogged filter.

6. Open drain valve of the filter and open air vent.

7. Dismantle cover of the casing and remove the filter

after complete emptying of oil.

8. Clean the filter element.

9. Insert the cleaned filter element.

10. Put cover and assemble filter.

11. Close the drain valve and open the air vent of the filter.

12. Open the inlet valve of the cleaned filter partially and slowly.

13. Close the filters air vent as soon as oil flows out through it.

14. Open outlet valve of the filter.

15. Now the cleaned filter is ready and can be kept as reserve.

9.3. OPERATION OF LDO PRESSURING PUMP

1. Ensure that no line clear or Safety permit is pending on the  LDO

pressurising pumping system.

2. Ensure that all drains in the LDO system are closed.

3. Select any one tank and check the oil level in the tank.

4. Open the tank outlet valve and check for closing of other tank

outlet valve.

5. Check for closing of LDO flushing to FO system.

6. Select any filter

7. If the filter is not already charged, close filter drain, open air

vent.

8. Open filter inlet valve partially.

9. Close the air vent as soon as oil comes out through it.

10. Open filter inlet valve and out let valves.

11. Now the filter is charged.

12. Select any one pump and open its suction and discharge valve.

13. Check the suction pressure of the pump.

14. Ensure the availability of instrument air supply to re-circulation

valve.

15. Open the inlet and outlet valves of the re-circulation valve.

16. Close the bypass of re-circulation valve.

17. Open the re-circulation valve to the tank.

18. Start the LDO pressurizing pump.

19. Check the motor for any spark, vibration, unusual noise, etc.

20. Check the pump for any vibration, unusual noise etc

21. Check the delivery pressure of the pump.

22. Ensure the operation of the re-circulation valve.

23. Verify the pressure of oil in the oil line to boilers.

24. Inform the respective boiler board engineer.

9.4. OPERATION OF LOD PRESSURING PUMP FILTER

1. Check the colour and differential pressure across the filter which

is in service.

2. If differential pressure exceeds 0.22 bar, the reserve filter is to be

taken into service.

3. Charge oil to reserve filter and then start the reserve pump.

4. For changing over to reserve filter only

5. Ensure the charged condition of the reserve filter

6. Open the inlet valve fully.

7. Close the suction valve of the reserve pump.

8. Open outlet valve of the reserve filter.

9. Close inlet and outlet valves of the clogged filter

10. Now reserve filter is in service.

11. Open the drain valve and then open air vent of clogged filter.

12. As soon as filter is drained, dismantle the casing cover and

remove the filter.

13. Clean the filter

14. Insert the filter element and assemble the casing cover.

15. Close the drain valve and open the air vent of the cleaned filter.

16. Open the inlet valve partially.

17. As soon as air is released completely, close the air vent.

18. Now the filter is charged and kept as reserve.

FUEL HANDLING SYSTEM OPERATION

STAGE – II

O &M MANUAL

CHAPTER – VII

OPERATION

OF

FURNACE OIL SYSTEM

CHAPTER - X

10. OPERATION OF FURNACE OIL SYSTEM

10.1. OPERATION OF SUCTION WATER

1. Ensure adequate stock of oil in the oil storage tanks.

2. Ensure the availability of trace heating steam (10 bar)

3. Ensure the availability of heating steam (17 bar)

4. Ensure the availability of instrument air supply to TCV in suction

heater.

5. Commission trace heating system of oil lines from tank to stage-II

FOPH.

6. Open air vent in the oil side of suction heater.

7. Open the inlet valve partially.

8. Once air is released, close the air vent.

9. Open the bypass valve of TCV and admit steam to the heater.

10. Commission the steam trap bypass drain.

11. Once water is drained completely, close the bypass and open

the steam trap valve.

12. Open inlet and outlet valve of TCV.

13. Close TCV bypass.

14. Open inlet valve of the heater fully.

15. Open the outlet valve.

16. Check the temperature control valve for its functioning.

17. Check the oil temperature in the oil line to FOPH.

10.2. OPERATION OF SUCTION FILTER

1. Select any one suction heater

2. Check the oil pressure and temperature before the filter.

3. Commission the trace heating system, jacketing steam etc.

4. Ensure closing of filter drain.

5. Open the air vent.

6. Open the inlet valve partially.

7. As soon as air is released, close the air vent.

8. Open the inlet valve fully.

9. Verify the differential pressure across the filter.

10. Open the outlet valve fully.

11. During running of FO system, check the differential

pressure across the filter.

12. If differential pressure across the filter is > 0.22 bar, then  take

the reserve filter in service.

13. Close the inlet and outlet valves of the filter.

14. Open the filter drain and air vent.

15. As soon as the oil is drained, dismantle the body cover.

16. Remove the filter element and clean.

17. Insert the cleaned filter element.

18. Assemble the cover and open the air vent.

19. Charge the filter.

20. Keep the filter as reserve.

10.3. OPERATION OF FUEL OIL PRESSURING PUMPS

1. Ensure commissioning of steam trace heating system

and electrical tracing  system.

2. Select any one pump.

3. Open the suction valve.

4. Check the suction pressure of the pump.

5. Open the delivery valve of the pump.

6. Start the pump.

7. Check the pump for its proper smooth running.

8. Check the delivery pressure of the pump.

9. Ensure the availability of instrument air supply.

10. Open the bypass valve of re-circulation valve.

11. Open the inlet and outlet valves of the re-circulation valve.

12. Check the re-circulation valve for its functioning.

10.4. OPERATION OF SECONDARY HEATERS1. Open the bypass line in the steam TCV.

2. Commission the steam trap by pass.

3. Ensure draining of water.

4. Open inlet and outlet valves of the steam trap.

5. Open inlet and outlet valves of TCV.

6. Observe the functioning of TCV.

7. Close the bypass line of TCV.

8. Open outlet valve of the secondary heater.

9. Check the re-circulation valve (PCV) for its operation.

10. Verify the temperature of oil at the heater outlet.

11. Check the pressure of oil at the heater inlet to find the operation of re-circulation valve

FUEL HANDLING SYSTEM OPERATION

STAGE – II

O &M MANUAL

CHAPTER – XI

TECHNICAL DATA

OF

PROCESS EQUIPMENTS & ACCESSORIES

CHAPTER - XI

11. TECHNICAL DATA PROCESS EQUIPMENTS &

ACCESSORIES

11.1. LDO TANKS

Number of tanks : 2

Capacity of the tank : 100m3

Diameter : 5.0M

Height : 6.0M.

11.2. LDO DECANTING PUMP – SUCTION FILTER

Number of filter : 2

Flow rate : 13.5Kl/Hr.

Size : NB 80/250 Microns

Manufacturer : M/s Sigma Industries,

Bombay

Differential pressure (clean) : 0.05 bar

Differential pressure (50%) : 0.22 bar

11.3. LDO DECANTING PUMPS

Number of pumps : 2

Capacity : 13.5 Kl/Hr. or 225 lpm

Delivery pressure : 4.5 Kg/Cm2

Type : TS 105/030

Make : TUSHACO Pumps

M/s Delta Corporation, Vapi

Drive :

3phase,415V,5.5Kw,1430rpm,

11 amps

Make : M/s Crompton Greaves Ltd.

11.4. LDO PRESSURIZING PUMPS – SUCTION FILTER

No. of filter : 2

Flow rate : 2.85 Kg/sec.

Working Pressure : 0.5 bar to 5 bar

Working temperature : 30oC

Type : 2 ½” – 150lbs – RF

Filter size : 1.65.1.220.500, Simplex,

500 Microns

Make : Boll & Kirch, Germany

Differential Pressure (Clean) : 0.05 Kg/Cm2

Differential Pressure (50%) : 0.22 Kg/Cm2

Body material : Carbon steel

Screen/Basket : Carbon steel/Aluminium

Wiremesh-Stainless

steel

Hydrostatic test pressure : 13 bar

Screen surface : 7563 Cm2

Gasket material : Rubber ‘Viton’

11.5. LDO PRESSURISING PUMPS

Number of pumps : Two

Capacity : 185 Lpm or 11.1 KL/hr

Discharge pressure : 35 bar

Type : SNH 120 ER 40 D 6.9 Wl2,

Screw pump.

Make : All weiler A.G.,Germany

Motor : 3phase,415V,18.5KW,

2940Rpm, 33 Amps

Type : 1MJ 6183-2CA90Z-BG180m

Make : Siemens, Germany.

11.6. FUEL OIL PRESSURISING PUMP SUCTION FILTER

Number of filters : Four

Flow rate : 8.5 Kg/Sec

Working pressure : 0.5 – 5 bar

Working temperature : 130o C

Type :

6”150lbsRF1.65.1.4.355.500.6”,

Simplex

Differential pressure (Clean) : 0.1 bar

Differential pressure (50 %) : 0.25 bar

Filter size : 500 microns

Make : Boll & Kirch, Germany

Body Material : Carbon Steel

Screen/Basket : C – Steel/Alu Wiremesh –

Stailess steel

Hydrostatic test pressure : 13 bar

Screen surface : 18575 Cm2

Jacketing steam : 10Kg/Cm2

Gasket material : Rubber ‘Viton’

11.7. FUEL OIL PRESSURIZING PUMPS

Number of pumps : 4

Capacity of the pump : 485-500 litres per minute

Delivery Pressure : 35 bar

Type : Screw pump

                                                      SMH 660 ER 40 E6.9 Y – W 12

– TOL 2.

Make : All Weiler A.G., Germany

Drive Motor : 3 phase, 415V, 45Kw, 1478 rpm,

78 amps.

Type : 1 MJ 6253 –4 CA90-Z,

BG250m

Make : Siemens, Germany

11.8. SECONDARY HEATERS

Number of heaters : 4

Manufacturer : OEL TECKNICK, GERMANY

Shell Side Tube Side

Diameter : 558.8 x 16mm ----

Length : 7150mm 6000mm

Number of tubes : ----- 224

Tube Diameter : ----- 20 x 2 mm

Volume : 900 litres 415 litres

Medium : Steam Fuel Oil

Design Pressure : 25 Ksc 40 Ksc

Design temperature : 300oC 150oC

Test Pressure : 37.5 Ksc 60 Ksc

Safety valve setting : 22 bar 40 bar

Operating Pressure : 18 Ksc 35 Ksc

Number of passes : 1 6

Temperature at inlet : 230oC 80-85oC

Temperature at outlet : 187oC 130oC

11.9. DRAIN OIL TANK

Number of tanks : 5 one in FOPH, one each in

4 -7 boiler (total 4)

Location : -6.4 m level in FOPH

Ground level in boilers

Capacity : 1m3

Size : dia 1000 x 1500 mm

Heating facility : By using steam

Heating tube : dia 48.3 x 3.7 mm

Heating area : 0.8 M2

11.10. DRAIN OIL PUMP FILTER

No. of filters : 1 + 4

Flow rate : 0.6 Kg/s

Working pressure : 10 bar

Working temperature : 130oC

Type : 1 ½” – 150 lbs – RF

1.65.1.4.160.250 Simplex

Filter size : 500 Microns

Make : Boll & Kirch, Germany

Differential Pressure (clean) : 0.1 bar

Differential pressure (50%) : 0.22 bar

Body Material : Carbon Steel

Screen/Basket : C – Steel/Alu Wiremesh–

Stailess steel

Hydrostatic test pressure : 13 bar

Screen surface : 2330 Cm2

Jacketing steam : 10 bar

Gasket material : Rubber ‘Viton’

11.11. DRAIN OIL PUMPS

Number of pumps : 1 + 4

Capacity of the pump : 0.62 Kg/s

Delivery Pressure : 5 bar

Type : Screw pump,

SMH 40 R 46 E6.0 W 72      

Make : All Weiler A.G., Germany

Drive Motor :

3phase,415V,1.1Kw,1450rpm,                                                        

2.65 amps.

Type : 1 MJ 5097 –4 CA90-Z, BG90L