Co-Combustion tests of coal and biomass using a pilot ... · Co-Combustion tests of coal and...
Transcript of Co-Combustion tests of coal and biomass using a pilot ... · Co-Combustion tests of coal and...
Co-Combustion tests of coal and biomass using a pilot-scale oxy-fuel
CFB
Yewen Tan, Lufei Jia and Yinghai Wu
Presented at the 3rd IEA Oxyfuel Combustion Conference, September 15, 2013
Oxy-CFB Advantages Fuel flexibility: coal, petcoke, biomass, waste and
co-firing In-situ sulfur capture with limestone Lower requirement for flue gas recycle when
external heat exchanger is used to cool return solids
Easier retrofit for existing CFB units Operation flexibility Co-firing biomass with CCS will have negative
CO2 emission levels
CanmetENERGY Oxy-FBC Research Facilities
A mini CFB test bed: 50 kW, can also be used for calcium/chemical looping cycle studies A pilot-scale CFB test bed: 0.8 MW Several TGAs and tube furnaces Analytical instruments
The 0.8 MWth Pilot-Scale CFB Can operate in air-firing and oxy-firing modes
with smooth transition between them Various fuel feed stocks can be used along
with limestone addition Internal diameter: 40 cm, height: 8 m Four movable water cooled tubes can used
for combustor temperature adjustment External heat exchanger currently being built Tested inlet O2 concentration is up to 30% All auxiliary gas streams are switched to RFG
during oxy-fuel tests
0.8MWth oxy-fuel pilot scale CFBC
Operating Procedure Warm up with natural gas using sand as bed material
until 800 C Start feeding test fuel Ramping up test fuel feed rate while cutting back on
NG until air-firing of test fuel is established Transition from air-firing to oxy-firing by cutting back
air flow while increasing flow rates of oxygen and recycled flue gas
Perform oxy-fuel test Transition back from oxy-firing to air-firing System shut down
Coal and Wood Pellets Analyses Wood pellet Lignite Bituminous Sub-bituminous
Proximate analysis
Moisture 9.52 13.23 6.7 6.08
Ash 0.38 11.33 14.18 24.72
Volatile 76.46 33.86 25.10 26.87
Fixed carbon 13.64 41.58 54.02 42.33
Ultimate analysis
Carbon 44.7 54.6 66.34 52.2
Hydrogen 5.36 3.50 3.64 3.05
Nitrogen 0.12 0.81 1.59 0.79
Sulphur <0.05 0.63 0.56 0.30
Oxygen (diff) 39.91 15.92 7.00 12.85
LHV, MJ/kg 17.49 20.74 25.28 19.98
Test Conditions Bituminous Sub-bituminous Lignite
Coal%/Wood
%
50/50 65/35 80/20 65/35 80/20 65/35
Fuel feed rate,
kg/hr
79.6±4.3 73.4±3.6 63.2±2.8 87.3±0.3 81.3±1.5 88.1±0.3
O2 in feed
gas, %
24.4±0.4 24.1±0.6 23.9±0.4 24.9±0.3 24.9±0.5 24.1±0.5
O2 flow rate,
kg/hr
118.2±4.2 116.9±5.6 100.1±4.8 126.9±4.1 117.1±5.0 115.8±5.3
O2 in flue gas,
%
2.1±0.8 2.6±1.1 1.5±0.9 2.8±0.4 4.0±0.8 2.2±0.9
CO2 in flue
gas, %
85.2±3.1 85.3±4.2 80.0±6.2 92.2±0.5 92.7±0.9 92.6±3.0
Flue gas
recycle ratio,
wt.%
68.3 68.8 65.2 72.6 75.7 70.0
Freeboard
temperature, °C
920 895 893 905 913 874
Superficial
velocity, m/s
4.9 4.7 4.3 4.7 4.7 4.4
Sulfur capture
ratio, %
Issues with SO2 analyzer 76.1 85.7 88.7
Concentrations of O2 and CO2 for 35% wood and 65% Genesee coal
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9 10
Elapsed Time, h
O2
and
CO
2, %
O2 CO2
Concentrations of CO, NO and SO2 for 35% wood and 65% Genesee coal
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 1 2 3 4 5 6 7 8 9 10
Elapsed Time, h
CO
an
d N
O,
pp
m
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
SO
2, %
CO NO SO2
Concentrations of O2 and CO2 for 35% wood and 65% Boundary Dam coal
0
10
20
30
40
50
60
70
80
90
100
8 9 10 11 12 13 14 15 16
Elapsed time, h
O2
and
CO
2, %
O2 CO2
Combustor freeboard temperature as a function of the amount of co-fired wood pellet in bituminous coal
0
100
200
300
400
500
600
700
800
900
1000
0 2 4 6 8 10 12 14
Time, hour
Tem
per
atu
re, d
eg. C
35% wood50% wood20% wood
Measured SO3 concentrations
Bituminous coal Measured SO3 concentrations, ppmv
20% wood, 80% coal <0.16
35% wood, 65% coal 2.23
50% wood, 50% coal 1.12
Genesee
100% coal 2.27
20% wood, 80% coal 2.76
35% wood, 65% coal 1.86
Emissions of VOCs for bituminous and wood mixture, (µg/m3) Wood% / bituminous%
VOC 20/80 35/65 50/50 0/100 Dichlorodifluoromethane (FREON 12) < 0.3 < 0.3 < 0.3 < 0.35
Chloromethane 6.25 3.29 5.84 22.0 Vinyl Chloride 0.24 < 0.2 < 0.2 < 0.2 Bromomethane 1.07 4.85 3.45 1.94 Chloroethane 0.22 < 0.15 < 0.15 < 0.16
Trichlorofluoromethane (FREON 11) < 0.15 < 0.16 < 0.17 < 0.18 Acetone (2-Propanone) < 0.67 2.12 0.87 1.23 1,1-Dichloroethylene < 0.15 < 0.16 < 0.17 < 0.2
Iodomethane < 0.22 2.58 0.96 0.35 Carbon Disulfide 13.5 4.31 3.48 4.75
Methylene Chloride(Dichloromethane) < 0.3 < 0.32 < 0.33 < 0.35 1,1-Dichloroethane < 0.18 < 0.19 < 0.2 NA
trans-1,2-Dichloroethylene < 0.15 < 0.16 < 0.17 NA cis-1,2-Dichloroethylene < 0.15 < 0.16 < 0.17 NA
Chloroform < 0.16 < 0.18 < 0.18 < 0.18 1,2-Dichloroethane < 0.1 < 0.11 < 0.12 < 0.1
Methyl Ethyl Ketone (2-Butanone) < 0.54 < 0.58 < 0.59 < 0.7 1,1,1-Trichloroethane < 0.21 < 0.23 < 0.23 < 0.2 Carbon Tetrachloride < 0.24 < 0.26 < 0.26 < 0.35
Benzene 1360 55.8 45.6 31.1 1,1,2-Trichloroethane < 0.24 < 0.26 < 0.26 < 0.16 1,2-Dichloropropane < 0.16 < 0.18 < 0.18 < 0.4
Trichloroethylene < 0.16 < 0.18 < 0.18 < 0.5 Dibromomethane < 0.15 < 0.16 < 0.17 1.94
Bromodichloromethane < 0.16 < 0.18 < 0.18 < 0.2 cis-1,3-Dichloropropene < 0.15 < 0.16 < 0.17 < 0.35
trans-1,3-Dichloropropene < 0.1 < 0.11 < 0.12 < 0.2 Dibromochloromethane < 0.13 < 0.15 < 0.15 < 0.4 Methyl Isobutyl Ketone < 0.3 < 0.32 < 0.33 < 0.2
Methyl Butyl Ketone (2-Hexanone) < 0.45 < 0.49 < 0.5 < 0.4 Toluene 42.6 4.59 2.10 < 0.18
Ethylene Dibromide < 0.15 < 0.16 < 0.17 < 0.2 Tetrachloroethylene < 0.27 < 0.29 < 0.3 < 0.1
Chlorobenzene < 0.16 1.20 0.40 < 0.16 1,1,1,2-Tetrachloroethane < 0.15 < 0.16 < 0.17 < 0.4
Ethylbenzene < 0.21 < 0.23 0.28 < 0.5 m / p-Xylene < 0.22 0.79 0.69 1.94
Styrene < 0.18 < 0.19 < 0.2 < 0.2 o-Xylene < 0.22 < 0.24 < 0.25 < 0.35
Bromoform < 0.21 < 0.23 < 0.23 < 0.2 1,1,2,2-Tetrachloroethane < 0.21 < 0.23 < 0.23 < 0.2
1,2,3-Trichloropropane < 0.22 < 0.24 < 0.25 < 0.2 1,3-Dichlorobenzene < 0.3 < 0.32 < 0.33 < 0.4
Emissions of metals for bituminous and wood mixture, (µg/m3)
Wood% / bituminous% Element 20/80 35/65 50/50
Al 80.6 < 57 < 53 Sb < 2.5 < 2.8 < 2.6 As < 2.5 < 2.8 < 2.6 Ba < 15 < 17 < 16 Be < 0.5 < 0.6 < 0.5 B 148 144 167 Cd 1.8 1.4 0.92 Ca 400 362 250 Cr < 1 < 1.4 < 1.3 Co < 0.5 < 0.6 < 0.5 Cu < 2 < 2.8 < 2.6 Fe < 150 < 170 < 158 Pb < 1.2 < 1.4 < 1.3 Mg 99.4 56.8 < 26 Mn < 2 < 2.8 NA Mo < 2.5 < 2.8 < 2.6 Ni 7.4 2.9 < 2.6 P < 25 < 28 < 26 K < 200 < 227 NA Se < 5 < 5.7 < 5.3 Ag < 1.2 < 1.4 < 1.3 Na 250 206 165 Sr < 1.5 < 1.7 < 1.6 Tl < 2.5 < 2.8 < 2.6 Ti 4.4 7.2 4.1 U < 2.5 < 2.8 < 2.6 V < 2.5 < 2.8 < 2.6 Zn 18.1 15.6 < 2.6 Hg 0.25 0.29 0.11
Conclusions
Stable oxy-cofiring conditions were achieved over relatively long operation hours The effect of wood pellets on CFB
freeboard temperature is minimal Stack sampling showed that SO3
concentrations were very low on our facility
Conclusions
Stack samplings for volatile organic compounds and metals also revealed low emission rates for both pollutants Test results confirmed one of the main
advantages of oxy-fuel CFB, which is its fuel flexibility
Future Work
Install the external heat exchanger Conduct high O2 concentration tests Initiating pressurized oxy-CFB work Fundamental research on specific
aspects of oxy-CFB combustion