Two-step hot coal gas desulphurization process integrated with direct production of elemental sulfur using iron-based sorbents: a preliminary study

The paper proposed a two-step desulphurization process using iron-based high temperature sorbents for removal of hydrogen sulfide from hot coal gases after coal gasification. The authors use the mixture of iron oxide with other metal oxides (e.g. Ce) supported by ash from a coalgangue- fired power plant to prepare high temperature desulphurization sorbents. The two-step desulphurization process is comprised of a first-stage desulphurization of removing majority of sulfur followed by a second-stage desulphurization to remove the remaining sulfur species. The process is integrated with effective sulfur recovery through direct elemental sulfur production during the regeneration of Fe/Ce based sorbents. Preliminary studies on sulfidation using a quartz fixed-bed reactor demonstrated that the Fe/Ce-based sorbents prepared in this study was able to remove >97% sulfur in the temperature range of 400-600°C. Simultaneous removal of organic and inorganic sulfur species was achieved.