A 32-Month gasifier mechanistic study and downstream unit process development program for the pressurized ash-agglomerating fluidized bed gasification system: Quarterly report, July 1-September 30, 1986

Work at KRW this reporting period focused primarily on design of an external hot gas zinc ferrite desulfurization process (Task 1) and PDU testing of an in-bed desulfurization and alkali removal system (Task 2) to develop PDU-scale data. Under Task 1, work continued toward finalizing subsystem design specifications and releasing procurement packages for system components so that PDU modifications can begin no later than December 1985. In-bed desulfurization testing at the PDU thus far has provided the following operational and process performance insights: in-bed desulfurization with dolomite is operationally feasible without great effect on gasifier performance and carbon utilization; dolomite feed and withdrawal rates can be independently controlled to assure dolomite balance; sulfur removal greater than 90% can be achieved with a high-sulfur (4.6%) coal versus 86% with a lower sulfur (2.4%) coal; maximum carbon conversion efficiency of 93% was achieved during TP-036-3 (S.P. 7B). Carbon conversion efficiency was affected by performance of the fines recycle system. Analyses of data collected to date show that the primary parameters influencing desulfurization efficiency are: high bed dolomite concentration, low moisture content of the product gas, the mass input of sulfur, and gas residence time. 67 figs., 23 tabs.