Biomass application in circulating fluidized bed coal firing boiler

Speaker Larry Tsai

Personal Information Work experience

Yuen Foong Yu packing Inc. XinWu mill Manager project department Yuen Foong Yu packing Inc. XinWu mill senior staff maintain department Yuen Foong Yu packing Inc. XinWu mill chief co-gen section Yuen Foong Yu packing Inc. XinWu mill deputy chief stoke preparation

section Project experience

Project manager for Yuen Foong Yu packing Inc. Yangzhou mill co-gen power plant phase 1 and Phase 2

Project manager for Yuen Foong Yu packing Inc. Cheng Kong mill coal firing boiler

Project manager for Chung Hwa pulp Inc. Chiutong mill co-gen power plant Education

Advanced degree Yuan Ze university master major in mechanical engineer

Secondary degree Chung Yuan major in chemical engineer

Biomass co-firing system in Europe

CO-firing power plant

What is fluidized bed?

Which kind of fuel can use in CFB boiler?

Typical properties of solid fuel

CFB boiler construction (conventional type)

CFB boiler construction (compact type)

How to work in CFB boiler

CFB boiler operation condition

CFB boiler power plant

FGD

CEMS

FGD

CaCO3

sand

ESP+bag filter coal

25%NH4OH SNCR

wood chip or Wood pellet

SCR(20 m3)

SOx NOx Dust Velocity CO

Flue gas temp. distribution in CFB boiler

850

850

850

420

150

FGD

ESP + bag filter

Air pollution control device for CFB

CaCO3 CaO+CO2+1/2O2

CaO

SO2

CaO+SO2+1/2O2CaSO4 CaSO4

NOx 150ppm(6%O2)

25%NH4OH

SNCR

NH4OHNH3+H2O 4NO+4NH3+O24N2+6H2O 6NO2+8NH37N2+12H2O SLIP

NH3

SCR NH4OHNH3+H2O 4NO+4NH3+O24N2+6H2O 6NO2+8NH37N2+12H2O

NOx

70ppm(6%O2)

SO2 80ppm(6%O2)

Summary for CFB boiler

Why choose a CFB boiler for co-firing system ? Fuel flexibility and multi-fuel firing, Low SO2 emissions due to efficient sulfur capture with limestone in the

furnace, Low NOx emission due to low combustion temperature and air-staging, Low CO and CxHy emission due to turbulent conditions and good

mixing, Secondary flue gas clean-up systems typically not needed, Stable operating conditions and good turn-down ratio, Support firing is not needed except during start-up periods, Increased capacity possible within the same footprint as old boilers, No need for fuel preparation (e.g. pulverizing).

Challenges of biomass co-firing Risk for biomass storage and transfer

High moisture and low bulk density Risk for high temperature corrosion and de-fluidize

Slagging and fouling on heat exchange surface Sintering in combustion chamber Slagging and fouling cause flue gas channel become narrow and

flue gas velocity increase. It cause erosion increase. High amount of alkali and chloride oxide component in flying

ash decrease melting point of ash and cause high temperature corrosion

High density inpurity material in biomass cause de-fluidized, if it cant discharge from bottom ash system smoothly.

Sintering matter from Combustion chamber

Slagging on furnace and ECO

Slagging on superheater

Superheater corrosion

Biomass & waste handling system

Reclaimer for biomass feeding system

Screw conveyor for biomass storage

Biomass pretreatment process

Pelletize for wood chip system

Moisture less than 90%

The relation of boiler efficiency & co-firing ratio

Why co-firing can reduce CO2 emission ?

Steam temp. & corrosion relative

Cogeneration power plant process

130 tons/hr 130 bar(A) 536

220

338

426 464 540

Ash composition of different fuel

Why SO2 and Alumininsilicates can reduce corrosion?

Alumininsilicates can react with alkalis liberating HCl Al2Si2O72H2O Al2O3 2SiO2 Al2O3 2SiO2+2KCl+H2O K2O Al2O3 2SiO2+2HCl

Sulphation of alkali chloride 2KCl +SO2+1/2O2+H2O K2SO4+2HCl

Gas effect

Mechanism of high temp. corrosion

Co-firing with coal can reduce corrosion

Economics sensitivity analysis electricity production cost vs. full load operation hours

biomass firing boiler

Intrex superheater

Biomass firing boiler of grip

Step grid

Open grid

Step gird for fluidized bed boiler

BFB boiler open grid

Step gird in CFB boiler

SNCR+SCR

Flue gas + NH3 slip

Catalyst

420

25% NH4OH

850

NH4OHNH3+H2O 4NO+4NH3+O24N2+6H2O 6NO2+8NH37N2+12H2O

ESP + bag filter

Johnson Matthay Honeycomb Catalyst

SCR

CaCO3

SO2 CaO

CaSO4 CaCO3 CaO+CO2+1/2O2

CaO+SO2+1/2O2CaSO4

850

CFB boiler de-sulfur, temp. and Ca/S relation

Biomass application in circulating fluidized bed coal firing boilerPersonal Information Biomass co-firing system in EuropeCO-firing power plantWhat is fluidized bed?Which kind of fuel can use in CFB boiler?Typical properties of solid fuelCFB boiler construction (conventional type)CFB boiler construction (compact type)How to work in CFB boilerCFB boiler operation conditionCFB boiler power plantFlue gas temp. distribution in CFB boiler Air pollution control device for CFBSummary for CFB boilerChallenges of biomass co-firingSintering matter from Combustion chamberSlagging on furnace and ECOSlagging on superheater Superheater corrosionBiomass & waste handling systemReclaimer for biomass feeding system 23Screw conveyor for biomass storageBiomass pretreatment processPelletize for wood chip system The relation of boiler efficiency & co-firing ratioWhy co-firing can reduce CO2 emission ?Steam temp. & corrosion relativeCogeneration power plant process Ash composition of different fuelWhy SO2 and Alumininsilicates can reduce corrosion? Mechanism of high temp. corrosionCo-firing with coal can reduce corrosionEconomics sensitivity analysis electricity production cost vs. full load operation hours biomass firing boilerIntrex superheaterBiomass firing boiler of gripStep gird for fluidized bed boilerBFB boiler open gridStep gird in CFB boilerSNCR+SCR Johnson Matthay Honeycomb CatalystSCR CFB boiler de-sulfur, temp. and Ca/S relation