7 - ChemNet gasifier applications

Abstract

This chapter develops ChemNet CFD postprocessing to characterize the char gasification channels and syngas compositions for entrained-flow gasifiers. The first case study at the lab-scale characterizes the conversion efficiencies and syngas compositions for co-gasification of coal with natural gas. A case study at pilot-scale evaluates predicted syngas compositions with three diverse coals from a second stage gasifier in which coal slurry is injected into syngas from a first reactor stage at moderate temperatures. The predicted CH4 concentrations are nearly flawless for all three coals, provided that slurry feedrates conform with assumptions behind the calculated coal thermal histories. The simulations correctly identify hv bituminous as the most effective CH4 producer, by far, as well as the least and most productive gasifier test conditions. Even though volatiles reforming is a primary source of CH4 in syngas, the predominance of hydrogasification of hv bituminous char is primarily responsible for the CH4 superiority of the hv bituminous coal.