Two-stage regeneration of zinc ferrite desulfurization sorbent

摘要

The Morgantown Energy Technology Center (METC) of the US Department of Energy (DOE) is interested in the potential of using a two-step process for regenerating the zinc ferrite desulfurization sorbent. In the first regeneration step, a gas mixture consisting of 12 percent SO(sub 2), 2 percent O(sub 2), and 86 percent N(sub 2) is used to convert zinc and iron sulfides to their sulfate forms using a sorbent bed inlet temperature of about 850(degrees)F (454(degrees)C). For the second step, the temperature is raised to about 1400(degrees)F (760(degrees)C), and the sulfates are decomposed to oxides with the concurrent release of sulfur dioxide. The same gas composition used for first step is also used for the second step. The proposed technique would require no steam and also has the advantage of producing a regeneration gas rich in sulfur dioxide. In a commercial operation, recirculating regeneration gas would be supplemented with air as required to supply the necessary oxygen. A bleed stream from regeneration (concentrated SO(sub 2) gas in nitrogen) would constitute feed to sulfur recovery.