Abstract |
A series of fixed-bed coal gasification and pyrolysis tests have been performed in a laboratory-scale reactor of 6.6 cm inside diameter. Chemical analyses were conducted on the product gas, the aqueous condensate, the tar, and the solid residue from the tests. The effects of process variables, such as feed mode, catalytic treatment, pressure, mesh size, and coal type, upon byproduct and pollutant yields are described. The production of gaseous sulfur compounds, benzene and derivatives (BTX), phenolics (phenol, cresols, and xylenols), and tar have been measured, and the fate of trace elements such as arsenic, selenium, and lead has been determined. Byproduct production associated with the pyrolysis phase of gasification has been investigated with emphasis on the effects of particle size, residence time, and atmosphere. Experiments conducted with six U.S. coals ranging from lignite to anthracite are described. Continuous operation was found to result in greatly reduced tar and phenolic production. When the entire mass of coal was introduced at the beginning of the test, effluent stream compositions more closely approached those of larger scale, fixed-bed gasifiers. Initial work on this project was reported in PB-287720; three more recent reports were EPA-600/7-79-200 through EPA-600/7-79-202. |