MODELING SULFUR-DIOXIDE CAPTURE IN A PULVERIZED COAL COMBUSTOR

The formation and capture of sulfur dioxide in a pulverized coal combu stor is investigated. A two-dimensional, steady axisymmetric code, PCG C-2 (Pulverized Coal Gasification and Combustion-two Dimensional), ori ginally developed at Brigham Young University, has been used to simula te combustion of the pulverized coal. This paper represents part of a project to investigate simultaneously enhancing sulfur capture and par ticulate agglomeration in combustor effluents. Results from the code h ave been compared to experimental data obtained from MTCI's (Manufactu ring Technology and Conversion International) test pulse combustor, wh ich generates sound pressure levels of similar to 180 dB. The overall goal behind the pulse combustor program at MTCI is to develop combusto rs for stationary gas turbines that use relatively inexpensive coal-ba sed fuels. This study attempts to model the capture of sulfur dioxide when injected into a pulse combustor firing micronized coal. While thi s work does not presume to model the complex gas flow-field generated by the pulsating flow, the effects of the acoustic field are expressed by increased heat and mass transfer to the particles (coal/sorbent) i n question. A comprehensive calcination-sintering-sulfation model for single particles was used to model the capture of sulfur dioxide by li mestone sorbent. Processes controlling sulfation are external heat and mass transfer pore diffusion, diffusion through the product layer of CaSO4, sintering, and calcination. The model was incorporated into the PCGC-2 program. Comparisons of exit concentrations of SO2 showed a fa irly good agreement (within similar to 10 percent) with the experiment al results from MTCI.