Mechanistic and kinetic studies of high-temperature coal gas desulfurization sorbents

Abstract

During this quarter work on zinc titanate materials as sorbents for fuel gas desulfurization continued. On the basis of the completed parametric studies of reduction and sulfidation (effects of H{sub 2}, H{sub 2}O, see quarterly reports {number sign}7, 8), ZnO and Zn-Ti-O materials were evaluated in terms of reduction-sulfidation kinetic differences. Comparative Arrhenius plots of the initial reduction and sulfidation rates are shown for the sorbents ZnO, Z2T-a (2Zn:1Ti) and Z2T3-a (2Zn:3Ti). The reduction rate is shown for a gas containing (mol) 10%H{sub 2}-3%H{sub 2}O-87%N{sub 2}, while sulfidation is for 2%H{sub 2}S-98%N2. The point at which the initial reduction rate becomes faster than sulfidation rate is 848,872 and 942{degree}C, respectively, for ZnO, Z2T-a and Z2T3-a. Therefore, Zn-Ti-O solids can be used for the desulfurization of coal-derived fuel gas at higher temperatures than single ZnO. To determine the regenerability of Zn-Ti-O solids and their sulfidation performance after regeneration, two cycles of consecutive sulfidation-regeneration were performed with ZnO and Z2T-a. 2 figs.