Effect of oxy-fuel combustion with steam and biomass addition on coal burnout in an entrained flow reactor

Transcription

1 Effect of oxy-fuel combustion with steam and biomass addition on coal burnout in an entrained flow reactor J. Riaza, L. Álvarez, M.V. Gil, C. Pevida, J.J. Pis, F. Rubiera National Coal Institute (INCAR-CSIC)

2 Figure by courtesy of Vattenfall

3 Entrained Flow Reactor Fuel N 2 / O 2 / CO 2 / H 2 O To evaluate the effect of: Water vapour recirculation in the oxyfuel combustion (10 and 20 vol. %). Biomass blending with the coal under oxyfuel conditions in an entrained flow reactor (10 and 20 w.%). Exhaust gases NO Emissions Burnout

4 Entrained Flow Reactor Feeding system Injector Cooling air Fuel Feeding system N 2 / O 2 / CO 2 / H 2 O Characteristics Wall temperature: 1273 K Reactor zone length: 1.4 m Reactor diameter: 40 mm Residence time 2.5 sec Continuous coal feeding system Gas analysers: O 2, CO 2, NO X, SO 2, CO Flow straighteners Pre-heater Heating resistance Insulator Sampling probe Cooling water Quenching gas Gas analysers O 2 N 2 O CO 2 CO Cyclone Filter Suction pump NO SO 2

5 Sample Proximate Analysis Ultimate Analysis (wt%, db) (wt%, daf) Ash V.M. F.C.+ C H N S O+ HV semi-anthracite SAB BA Rank/Origin high-volatile bituminous coal high-volatile bituminous coal db: dry basis; daf: dry and ash free bases; *Calculated by difference. HHV (MJ/kg,db) OR olive residue µm

6 BIOMASS ADDITION + 10 % + 20 % WEIGHT WATER VAPOUR ADDITION

7 Burnout (%) 79%N2-21%O2 70%CO2-30%O2 79%CO2-21%O2 65%CO2-35%O SAB 90%SAB-10%OR 80%SAB-20%OR

8 Burnout (%) %N2-21%O2 70%CO2-30%O %CO2-21%O2 65%CO2-35%O , HV 90%HV-10%OR 80%HV-20%OR SAB 90%SAB-10%OR 80%SAB-20%OR

9 Fuel N 2 / O 2 / CO 2 21 % O 2-79% N 2 21 % O 2-79% CO 2 30 % O 2-70% CO 2 35 % O 2-65% CO 2 NO Emissions Exhaust gases

10 mg NO / g burned fuel %N2-21%O2 70%CO2-30%O2 79%CO2-21%O2 65%CO2-35%O SAB 90%SAB-10%OR 80%SAB-20%OR

11 mg NO / g burned fuel 10,00 9,7 79%N2-21%O2 70%CO2-30%O2 79%CO2-21%O2 65%CO2-35%O2 Sample N HV 1.9 SAB 2.1 OR 1.9 8,00 6,00 7,4 6,7 6,9 8,8 7,1 6,5 6,5 6,6 6,6 6,5 6,1 6,3 5,0 5,1 5,2 5,2 NH 3 HCN NO 4,00 4,2 4,0 3,9 3,6 2,00 2,6 2,2 2,4 0,00 HV 90% HV-10% OR 80% HV-20% OR SAB 90%SAB+10%OR 80%SAB+20%OR

12 BIOMASS ADDITION + 10 % + 20 % WEIGHT Dry recycle WATER VAPOUR ADDITION 0% H 2 O 10% H 2 O 20% H 2 O 21% O 2-79% N 2 21% O 2-69% N 2-10% H 2 O 21% O 2-59% N 2-20% H 2 O 21% O 2-79% CO 2 21% O 2-69% CO 2-10% H 2 O 21% O 2-59% CO 2-20% H 2 O 30% O 2-70% CO 2 30% O 2-60% CO 2-10% H 2 O 30% O 2-50% CO 2-20% H 2 O 35% O 2-65% CO 2 35% O 2-55% CO 2-10% H 2 O 35% O 2-45% CO 2-20% H 2 O Wet recycle

13 Burnout (%) HV HV+ 10%H2O HV+ 20%H2O BA BA+ 10%H2O BA+ 20%H2O 50 21%O2-79%N2 21%O2-79%CO2 30%O2-70%CO2 35%O2-65%CO2

14 mg NO / g burned fuel 10,00 9,7 8,00 6,00 4,00 2,00 0,00 7,7 7,4 6,7 6,9 6,7 6,9 6,8 6,3 6,5 6,6 6,4 6,1 5,9 6,0 5,5 5,6 5,0 5,2 4,8 HV HV+5%H2O HV+10%H2O HV+20%H2O BA BA+10%H2O BA+20%H2O 79%N2-21%O2 79%CO2-21%O2 70%CO2-30%O2 65%CO2-35%O2

15 Replacing N 2 by CO 2 caused a decrease in the burnout values. When the O 2 concentration was increased to 30% the burnout value was higher than in air conditions. A increase in the burnout value was observed after the addition of biomass. The emissions of NO during oxy-fuel combustion were lower than under air. However, they remained similar under all the oxy-fuel atmospheres with increasing O 2 concentrations. Emissions of NO were significantly reduced by the addition of biomass to the bituminous coal, although this effect was less noticeable in the case of the semianthracite. No significant effect was observed in the burnout after the addition of steam. In general the presence of steam reduce the emissions of NO

16 Effect of oxy-fuel combustion with steam and biomass addition on coal burnout in an entrained flow reactor Thanks for your attention! Acknowledgements CSIC (Project PIE E09). J.R. acknowledges funding from the Government of the Principado de Asturias. L.A and M.V.G. acknowledge funding from the CSIC JAE-Pre and CSIC JAE-Doc programs, respectively, co-financed by the European Social Fund.