Simultaneous removal of H{sub 2}S and NH{sub 3} in coal gasification processes. Progress report, October 1, 1995--December 31, 1995

The objective of this project is to develop successful combination of an NH{sub 3} decomposition catalyst with the mixed-metal oxide sorbent so that the sorbent-catalyst activity remains stable for NH{sub 3} decomposition in addition to H{sub 2}S removal under cyclic slufidation-regeneration conditions in the temperature range of 550-800{degrees} C (1022-1472{degrees}) F and pressures up to 20 atm. The project consists of the following three tasks: (1) sorbent-catalyst preparation and characterization; (2) experimental testing; and (3) cyclic testing. Under task 2, activities of the HART 48 and 49 sorbent-catalysts containing Mo were tested using the simulated coal gas. The H{sub 2}S removal ability is shown in Figures 3 & 4 and its ammonia decomposition activity is shown in Figures 1 & 2. Figures 3 & 4 show that H{sub 2}S breakthrough profiles as a function of time. The pre-breakthrough H{sub 2}S level was below 60 ppm. Nearly complete sorbent conversion (100%) was observed at breakthrough. The HART 48 & 49 sorbent-catalysts showed moderate catalytic activity (50- 55% average conversion) for ammonia decomposition. Initially, up to 150 min all the sorbent-catalysts showed a very high activity (>90%). The decline in activity after 250 min, is mainly due to the posioning of the catalyst by H{sub 2}S