Operation characteristics of 1 ton/day-scale coal gasifier with additional stage

摘要

A one-stage coal gasifier was modified to accommodate the two stages of coal feeding. Operating characteristics were compared between the one-stage and two-stage gasification in terms of syngas composition, carbon conversion, shape and inner structure of produced slags, characteristics of particle size distribution in entrained fines, and effects on particulate removal facilities. Temperature at the second stage of the gasifier resulted in lower values, which confirms the performance of the second stage as a reduction area by endothermic reactions. The results suggest that the 10-20% increase in coal feeding to the second stage might not cause much loss in carbon conversion. Produced slag and the performance of metal filters and water scrubber were similar with the earlier results from one-stage gasification tests. The two-stage gasification appears to help in increasing the cold gas efficiency for the certain operating range. Two-stage gasification had an impact on the 0.1-1 urn size of entrained fines, which appear to be cenospheres that occur during the rapid quenching in temperature.