Power plant FUEL FIRING SYSTEM india.pptx

presentation on power plantFUEL FIRING SYSTEM.pptx

1. FUEL FIRING SYSTEM: COAL FEEDER, PULVERISER, OIL FIRING SYSTEM,BURNERS BARH BY: BHAIYA KAMALENDU Sr Manager(operation)

2. 2 What is COMBUSTION ?

3. 3 3 REQUIREMNTS FOR COMBUSTION

4. 4 3 Ts of Combustion TIME All combustion requires sufficient Time which depends upon type of Reaction TEMPERATURE Temperature must be more than ignition temperature TURBULENCE Proper turbulence helps in bringing the fuel and air in intimate contact and gives them enough time to complete reaction.

5. 5 What are the various types of combustion? There are three types of combustion: -- Perfect -- Complete  -- Incomplete   Perfect Combustion is achieved when all the fuel is burned using only the theoretical amount of air, but perfect combustion cannot be achieved in a boiler. Complete Combustion is achieved when all the fuel is burned using the minimal amount of air above the theoretical amount of air needed to burn the fuel. Complete combustion is always our goal. With complete combustion, the fuel is burned at the highest combustion efficiency with low pollution.  Incomplete Combustion occurs when all the fuel is not burned, which results in the formation of soot and smoke.

6. 6 Optimising Excess Air In practice Excess Air over Stoichiometric air is needed for complete combustion Less Air  Incomplete combustion & Smoke More Air  Heat loss through stack CO 2 or O 2 values will indicate excess air level Typical Excess Air Level for Oil Fuel is 25 –30 % CO 2 % 14.5 - 15 % O 2 % 2 - 3 %

7. OIL FIRING A coal fired unit incorporates oil burners to a firing capacity of 30% of boiler load for the following reasons: a) To provide necessary ignition energy to light-up coal burner. b) To stabilize the coal flame at low boiler/burner loads. c) As a safe start-up fuel and for controlled heat input during light-up.

8. 8 Oil The various types of oils used as fuel are Furnace oil, LSHS, H.P.S., L.D.O, Kerosene, Diesel etc The properties of liquid fuels of importance are water content, density, specific gravity, Viscosity, Calorific value, Sulphur, Ash and carbon residue

9. MAJOR COMPONENT OF OIL FIRING OILGUN IGNITOR HONV: Heavy oil nozzle valve ASNV: Atomizing steam nozzle valve Scavenging valve HOTV: Heavy oil trip valve LOTV: light oil trip Valve HFO/LDO pumps HORV: Heavy oil recirculation valve

10. Fuel Oil System LDO/HFO is used as fuel oil. 20 numbers of LDO /HFO burners are supplied. LDO capacity is 30% of BMCR requirement of heat capacity to cater to Steam generator. The atomizing medium of light oil is air, which is supplied from service air system to an individual boiler supply line. The atomizing air has to be maintained at burner 5.5-7kg/cm2g. LDO pressure is main tained at 8-10 Ksc HEA ingitors are used to ignite LDO. Capacity maximum : 30 % M C R tot a l in 5 elevation Number of oil guns : 20 (4 per elevation) Location of oil gun : AB BC DE FG HJ

11. IGNITER ARRANGEMENT

12. IGNITOR high energy spark type igniter for direct ignition of the atomized oil during oil burner light off. Spark rate of 4 sparks per second. The igniter is also brought into service when the oil gun is purged to remove oil from the gun on a controlled shutdown or when being manually purged. Advance retract mechanism: Pneumatic type with single solenoid - Safe state: Retracted - Igniter spark time (during normal firing): 15 s Igniter spark time (during purge): 30 s

13. FLAME SCANNERS Each oil burner and each PF burner are equipped with its dedicated flame scanner optimised to detect the flame from its own burner. Same flame scanner for Oil flame and coal flame with different detection electronics The flame scanner is suitable for operation in ambient temperature up to 85 degC . The flame scanner is supplied with cooling air from scanner air fan. The cooling air serves to protect the electronics and It shields the components from hot and/or aggressive gases and dusts.

14. AIR COOLED OIL GUN OIL GUN SUPPLIES ATOMISED OIL TO FURNACE. OIL GUN IS AIR COOLED. OIL GUN IS ALWAYS IN FIRING POSITION. SAME OIL GUN FOR LIGHT OIL AND HEAVY OIL

15. WINDBOX ARRANGEMENT

16. PULVERISED FUEL FIRING SYSTEM In a pulverised fuel firing system the coal is reduced to a fine powder with the help of grinding mill and then projected into combustion chamber with help of hot air. The amount of air which is used to carry the coal and to dry it before entering into combustion chamber is known as primary air. The amount of air required (Secondary air) to complete the combustion is supplied separately to the combustion chamber. The resulting turbulence in the combustion chamber helps for uniform mixing of fuel and air through combustion. The efficiency of pulverised fuel firing system mostly depends on the size of the powder.

17. WHY PULVERISED FUEL The economic motives for the introduction and development of pulverized fuel firing are: Efficient utilization of cheaper low grade coals . Better response to automatic control Flexibility in firing with ability to meet fluctuating loads. Ability to use high combustion air temperature; increasing the overall efficiency of boiler. High surface area

18. PULVERISER AND FEEDERS

19. MILL CONSTRUCTION AND WORKING

20. Features of Bowl Mills Grinding chamber Classifier mounted above it Pulverization takes place in rotating bowl Rolls rotating free on journal do the crushing Heavy springs provide the pressure between the coal and the rolls Rolls do not touch the grinding rings Tramp iron and foreign material discharged.

21. Role of Mills Produces Pulverized coal 80% of which passes through 200 mesh Air mixed with Pulverized coal (PF) is carried to the coal nozzle. PF from coal nozzle is directed towards the centre of boiler burning zone Pre-heated secondary air enters boiler and surrounds the PF and help in combustion

22. Mill Designation Furnace Mill J Mill H Mill G Mill F Mill E Mill A Mill B Mill C Mill D 1 2 3 4

23. MILL PERMISSIVES MILL OFF SWGR AVAILABLE SEAL AIR MILL DP OK IGNITION PERMIT AVAILABLE MILL LUB OIL SYSTEM READY MILL DISCHARGE VALVE OPEN MILL OUTLET TEMP NOT HIGH COLD AIR GATE OPEN NO UNSUCCESSFUL START TRAMP IRON VALVE OPEN PRIMARY AIR PERMIT BUNKER OUTLET GATE OPEN FEEDER I/L GATE OPEN BUNKER ISOLATIN GATE OPEN NO TRIP CONDITION

24. COAL ELEVATION LOGIC PULVERISER LOGIC This logic takes the count of total no. of pulverisers in service at any point of time No. of FD Fans and PA fans in service. With PA Fan ‘ON’ and PA Header Pressure adequate, it gives “PA permit” to start the Pulverizer . In case of PA Header Pressure going low-low or PA/ FD fans trips, it ensures the shut down of Pulverizers from top elevation to bottom elevation in a timed sequence.

25. IGNITION PERMIT FOR MILL PRIOR TO START ANY MILL THE MILL IGNITION ENERGY MUST BE ADEQUATE TO SUPPORT COAL FIRING MINIMUM 3 OUT OF 4 HONVs OF ELEV. AB OPEN OR MILL- ‘A’ OR “C” IN SERVICE WITH>50% LOADING AND BOILER LOAD IS > 30%

26. MILL PROTECTIONS MASTER FUEL TRIP FSSS LUB OIL TRIP MILL DISCHARGE V/V NOT OPEN IGNITION ENERGY NOT AVAILABLE EPB PRESSED SEAL AIR MILL DP LOW BUNKER ISOLATING GATE NOT OPEN LOSS OF PRIMARY AIR FSSS MILL BEARING TEMP VERY HIGH MOTOR BEARING TEMP VERY HIGH

27. MILL COMPONENTS HAG:- Hot air gate HAD:- Hot air Damper (Control the total air to the Mill. CAG:- Cold air gate CAD: Cold air Damper (controls the Mill outlet temperature) Mill lube oil system Seal air system Mill instrumentation Mill outlet temperature Air inlet temp, Motor Bearing and winding temp Air flow Oil level Oil flow Oil pressure Motor vibration

28. PULVERISER SEAL AIR

29. MILL REJECT SYSTEM Mill reject are dense, difficult-to-grind foreign material Rejects are moved by rotating scraper assemblies, to an opening in the millside floor. The rejected foreign material falls out of the pulverizer and enters the pyrite system. Rejects are removed in auto in either Timer mode or Probe mode P V 1 Mill scraper chamber Reject box PV2 P V 4 Denseveyor P V 3

30. Mill PARAMETERS

31. Raw coal Feeder Coal feeder supply coal to the mill. Feeder control the rate of coal feeding to the mill. Received coal from bunker Load cells to measure weight Tacho generator to measure speed Eddy current clutch/ VFD drive for speed control

32. FEEDER MODES OF OPERATION GALVIMETRIC MODE:- Both belt scale and belt speed in service in service feed rate = weight(kg/m)*belt speed(m/s) # weight found out by load cell. ##feed rate corrected by changing belt speed VOLUMETRIC MODE :- Only belt speed in service. Feed rate= volume(m3)*density(kg/m3) *belt speed(m/s)/span

33. FEEDER INSTRUMENTS LOAD CELL COAL ON BELT FEEDER INLET VALVE DISCHARGE VALVE DISCHARGE PLUGGED SWITCH INDUCTION MOTOR. EDDY CURRENT CLUTCH/ VFD DRIVE COC MOTOR SHEAR PIN (COC) SEAL AIR VALVE

34. FEEDER PERMISSIVE PULV IGN AVAL PULV READY FEEDER SPEED TO MINIMUM NO MFT FDR IN REMOTE PULV ON FEEDER SEAL AIR VLV OPEN MILL AIR FLOW ADEQUATE>70 T/HR MILL OUTLET TEMP ADEQUATE> 60 C

35. PULV OFF NO COAL FLOW TRIP MFT ELEV NO IGNITION ENERGY FEEDER TRP FROM PANEL MILL OFF COMMAND FEEDER PROTECTION

36. THANK YOU