fuel oil and fuel firing system

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A presentation on FUEL OIL & FUEL FIRING SYSTEM )

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Page 1: Fuel Oil and Fuel Firing System

A presentation on

FUEL OIL & FUEL FIRING SYSTEM)

Page 2: Fuel Oil and Fuel Firing System

Fuel Oil

Three liquid fuels used in power plantsHeavy Fuel Oil (HFO)LSHS (Low Sulfur Heavy stock)Light Diesel Oil(LDO)

Oil firing is preceded byLowering viscosity and increasing flowability on heating for better combustion in given turn down ratio.(125oC)Droplet formation on atomization (by steam/ compressed air/ mechanical pressurization) Combustion initiation by High energy spark ignition

Page 3: Fuel Oil and Fuel Firing System

Method of firing

Down shot firingFront fired

Single wallOpposed wall

Corner fired Tangential tilted

(-30o to +30o)Fluidized bed combustion

For Anthracite (Low VM)Bituminous (High/ medium VM)

Bituminous (Medium VM)

Lignite, peat, garbage (For low CV, high ash, high Sulphur)

Page 4: Fuel Oil and Fuel Firing System
Page 5: Fuel Oil and Fuel Firing System

Coal for combustionAnthraciteSemi-anthraciteBituminousSemi-BituminousLignitePeat

High CV, low VM High CV, low VM Medium CV, medium VM Medium CV, medium VM Low CV, high VM, high TM Very low CV, high VM & TM

Page 6: Fuel Oil and Fuel Firing System

Combustion air arrangement in furnace

Fuel air is supplied around coal nozzles (at velocity of 30-35 m/sec).

Secondary air is supplied in adjacent tiers of sec. air dampers from wind box (Hot air from Secondary APH)

Overfire/ Tempering air is supplied at the top of the burner zone for NOx control.

Gas recirculation is adopted for steam temperature control in oil/ gas fired units.Furnace draft is maintained at -5 mmwc with Forced and Induced draft fans (balanced draft)

Page 7: Fuel Oil and Fuel Firing System

Tangential corner fired boilers

Suitable for sub bituminous and bituminous coalMore uniform heat absorption in furnace wallsInherent feature of low NOx formation due air deficit region at centreAir plenum near walls reduce slagging and prevent fireside corrosion.Arrangement of steam temperature control by tilting the coal burners (-30o to +30o)

Page 8: Fuel Oil and Fuel Firing System
Page 9: Fuel Oil and Fuel Firing System

Flame visualization in tangential corner fired boilers

Burner tilt (UP) Burner tilt (Horizontal) Burner tilt (Down)

Page 10: Fuel Oil and Fuel Firing System

Optimization ofOptimization of total air supplytotal air supply

Boi

ler l

oss %

CO2%

Page 11: Fuel Oil and Fuel Firing System

Variation of CO with O2 in flue gas

Page 12: Fuel Oil and Fuel Firing System

Fuel Firing System

Burners Coal Fuel oil Light oil Igniters (HFO) (LDO) a)Quantity, 24 12 4 4 C)Atomization (Steam) (Air)

Page 13: Fuel Oil and Fuel Firing System

Heat loss Vs Excess air

40

30

20

10

20 40 60 80 100 % of excess air

Excess air for minimum loss

PF firing 20%Oil firing 10%

Page 14: Fuel Oil and Fuel Firing System

FUEL OIL SYSTEM

• STORAGE TANK DATA

• Description HFO Tank LDO Tank • Capacity(m3/hr) 2000 1000 • Numbers 2 1 • Tank size 16IDX12H 12IDX10H

Page 15: Fuel Oil and Fuel Firing System

UNLOADING PUMPS

• Description • Wagon unloading pumps• Service HFO/LSHS LDO • No's (4+2) (2+1) • Type Twin Screw Twin Screw • Capacity (150+25) (25+10)

Page 16: Fuel Oil and Fuel Firing System

FUEL OIL CHARACTERISTICS

Page 17: Fuel Oil and Fuel Firing System

LDO /HFO ANALYSIS

Page 18: Fuel Oil and Fuel Firing System

Combustion airTheoretical air for complete combustion is known as stoichiometric air.Excess air for completion of combustion (20% at MCR i.e. 3.6% O2)

Total combustion is divided asPrimary air For drying & pulverized coal transportationSecondary air Additional air for combustionRatio of SA/ PA = 2:1 (Approx)

%21%

2

2

OOExcessAir

Page 19: Fuel Oil and Fuel Firing System

QUESTIONS