Characteristics of Biomass. Needs

Transcription

1 Characteristics of Biomass Combustion in a CFB Boiler Jong-Min Lee, Dong-Won Kim, Jae-Sung Kim Green Growth Laboratory Korea Electric Power Research Institute Needs Limited supply of domestic anthracite Fuel Type Coal Consumption Boiler Type Tonghae CFB Boiler Anthracite coal 4,900 ton/d (1.47 mil. ton/d) Circulating Fluidized Bed Capacity 400 MWe (200 MWe 2) Steam Capacity 1,300 ton/h (660 ton/h 2) Operation Unit 1: from Sept. 30, 1998 Unit 2: from Sept. 30, 1999 Year OR(%) Soaring of coal price CO2 reduction 1

2 Problems are... Pouring money into power plant, and emission of CO 2! Solution is... Fuel Diversification Low grade coal Biomass Objectives Evaluation of Feasibility of & Biomass for Complementary Fuel in a Commercial CFB Boiler. 2

3 /Biomass Distribution Waste Generation (Unit: 1,000ton/y) Biomass Potential (Unit: TOE) (M) : Municipal Waste ( I ) : Industrial Waste Plant 2,854(M) 648( I ) 765(M) 283( I ) 3,929(M) 361(I) Plant 584(M) 33( I ) Tonghae CFB 711(M) 121( I ) 545(M) 92( I ) 689(M) 118( I ) 577(M) 131( I ) 468(M) 239( I ) 493(M) 103( I ) 937(M) 193( I ) 946(M) 122( I ) 783(M) 278( I ) 383(M) 287( I ) 1,421(M) 310( I ) Fuel Analyses Spec. Korean Anth. Wood Pellet Size (mm) < 6 < 50 < 50 Calorific value [HHV] (kcal/kg) Proximate Analysis (wt.%) 4,599 4,182 4,226 Moisture FC VM Ash C H Ash (wt.%) Spec. Korean Anth. Wood pellet SiO Al2O Fe2O CaO MgO Na2O K2O Ultimate Analysis (wt.%) O N S SO TiO Others Ash Cl Wood Pellet Ash IDT ( o C) 1,450 1,025 1,257 3

4 Experimental Preparation /wood pellet feeding site /wood pellet feeding system TGA Analyses Korean Anthracite Wood Pellet X [-] o C/min 10 o C/min 20 o C/min 30 o C/min Temperature [ o C] Weight Loss (X) [-] Weight Loss (X) Derivative Weight Loss (dx/dt) st 2nd 3rd region region region Wood Pellet 5 o C/min Temperature [ o C] Derivative Weight Loss (dx/dt) [ 1/min] 4

5 Effect on Temperature (Bituminous coal) Temper rature [ o C] Furnace Temp. Outlet-Left Outlet-Center Outlet-Right t All Data Regression MS 2.37 FC VM Ash Bituminous Coal Ratio [%] Backpass Gas Flow Gas Flow Coal Silo [ o C] Cyclone Outlet - Left Cyclone Outlet - Center Cyclone Outlet - Right All Data Regression Cyclone Solid Flow Boiler Solid Flow Temperature FBHE Windbox FBAC Primary Bituminous Coal Ratio [%] Effect on Temperature (/Wood pellet) Temperature [ o C] Furnace Lower Part Furnace Upper Part Furnace Exit Cyclone Exit Temperature [ o C] Furnace Lower Part Furnace Upper Part Furnace Exit Cyclone Exit Wood Pellet Co-Combustion Ratio [%] 5

6 Effect on Pressure () [mmh 2 O] op [mmh 2 O] Total Pressure Drop Total Pressure Drop Lower Part Pressure Drop Lower Part Pressure Dr Backpass Gas Flow Cyclone Solid Flow Gas Flow Boiler Coal Silo Middle Part Pressure Dr rop [mmh 2 O] Middle Part Pressure Drop Upper Part Pressure Drop p [mmh 2 O] Upper Part Pressure Drop Primary FBHE Solid Flow Windbox FBAC Effect on Emissions (NOx, SO 2, Limestone, etc) SO 2 & NOx Emission [ppm, 6% O 2 ] S SO 2 NO x Limestone Limestone Feeding Rate [t/h] O2 & NOx Emission [ppm, 6% O2] S SO 2 NO x Limestone Limestone Feeding Rate [t/h] Wood Pellet Co-Combustion Ratio [%] 6

7 Effect on Emissions (Cl & Dioxins) HCl Emission [ppm] Chlorine in Chlorine in Ash HCl in Flue Gas Amount of Chlorine [kg/day] Dioxins [ng-teq/sm 3 ] Regulation limit Wood pellet Effect on Eluted HMs Conditions () 0 % 1 % 3 % 5 % Regulation F/A B/A F/A B/A F/A B/A F/A B/A Pb (mg/l) ND ND ND 0.02 ND 3.0 Cu (mg/l) ND ND As (mg/l) ND ND Hg (mg/l) ND ND ND ND ND ND ND ND Cd (mg/l) ND ND ND ND ND ND ND ND 0.3 Cr 6+ (mg/l) ND ND 0.09 ND 0.11 ND 0.16 ND 1.5 CN - (mg/l) ND ND ND ND ND ND ND ND 1.5 Conditions 0 % 1 % 3 % 5 % Regulation (Wood pellet) F/A B/A F/A B/A F/A B/A F/A B/A Pb (mg/l) ND ND ND ND ND ND ND ND 3.0 Cu (mg/l) ND ND ND 1.0 As (mg/l) ND ND Hg (mg/l) ND ND ND ND ND ND ND ND Cd (mg/l) ND ND ND ND ND ND ND 0.3 Cr 6+ (mg/l) ND ND ND ND ND ND 0.16 ND 1.5 CN - (mg/l) ND ND ND ND ND ND ND 1.5 7

8 Effect on EP performance ( & Biomass) SI-TR output () SI-TR output (Biomass) Power Generation Improvement low [MW/ t/h] Power Gen./Coal F Wood Pellet Actual Power Gen./Coal Flow Power Gen./Coal Flow based on Heating Value Bituminous Coal Ratio [%] Bituminous coal Co-combustion ratio 0% 1% 3% 5% Power Generation(MW) Coal consumption(t/h) Heating value of fuel (kcal/kg) 4,842 4,968 4,966 4,844 Supplying heating value (Gcal/h) Power Generation/Supplying heating value (MWh/Mcal)

9 Conclusions Co-firing of & Biomass with Korean anthracite in Tonghae CFB boiler increased temperatures of the furnace exit decreased emission level of SO 2 unchanged emission level of Nox HCl emissions were below 1 ppm and captured by limestone Dioxin i emissions i were about ~ ng-teq/sm 3 caused unstable operation of EP over 5% co-firing &Biomass would be supplementary fuels in the CFB Boiler. 9