Performance of Zinc Ferrite Sorbent in Simulated Hot Coal Gas from the KRW Process Development Unit

摘要

The series of tests carried out, in which simulated oxygen- and air-blown coal gas from the KRW process development unit was passed through zinc ferrite sorbent in a laboratory-scale unit, has demonstrated that the sorbent can function in the regime of gas composition and temperature planned for pilot-scale tests, lowering H sub 2 S concentration to a few ppM by weight. There is evidence that at 1200 exp 0 F and above, wustite is formed in both oxygen- and air-blown cases, resulting in a lower sorbent conversion to sulfide before hydrogen sulfide breakthrough. Thus, operation above 1200 exp 0 F and at lower steam concentrations in the gases than those employed in these tests is not recommended. The amount of zinc carry over, less than 1 ppM in the gas, is thought to be acceptable. This level would be an order of magnitude smaller (based on zinc vapor equilibrium) at the higher pressure of operation of the KRW process development unit. There is a relatively small drop in sorbent surface area at the temperatures investigated but, in the absence of long-term cumulative effects, this will probably be tolerable. Also, sorbent crush strength is not altered markedly by the sulfidation process. In fact, sulfidized sorbent generally has a higher crush strength than fresh sorbent. Virtually no carbon deposition occurred during the tests and the reactor differential pressure remained constant at a low level. 6 refs., 25 figs., 18 tabs. (ERA citation 10:050735)