Simultaneous removal of H{sub 2}S and NH{sub 3} in coal gasification processes. [Quarterly report], January 1, 1996--March 31, 1996

The objective of this study is to develop advanced high-temperature coal gas desulfurization mixed-metal oxide sorbents with stable ammonia decomposition materials at 550-800{degree} C (1022- 1472{degree} F). The specific objectives of the project are to: (1) develop a combined sorbent-catalyst materials shall be capable of removing hydrogen sulfide to less than 20 ppmv and ammonia by at least 90 percent (objective completed); (2) carry out comparative fixed-bed studies of absorption and regeneration with various formulations of sorbent-catalyst systems and select most promising sorbent-catalyst type (also completed); (3) conduct long-term (at least 30 cycles) durability and chemical reactivity in the fixed-bed with the superior sorbent-catalyst. Since HART-49 sorbent-catalysts showed a very promising catalyst activity for ammonia decomposition it was decided to run the multicycle runs using HART-49 sorbent-catalysts. Initially, up to 180 min the sorbent catalyst showed a very high activity ({gt}90{percent}). The decline in activity after 180 min is mainly due to the poisoning of the catalyst by H{sub 2}S. The pre-breakthrough H{sub 2}S level was below 20 ppm. Complete sorbent conversion was observed at breakthrough. The average conversion was increased from 54 to 70 {percent} as the temperature was increased from 500 to 770 {degree}C for HART-49 sorbent catalysts. Additional multicycle runs will be conducted using HART-51 sorbent-catalysts. 5 refs., 6 figs