Kinetics of Mn-based sorbents for hot coal gas desulfurization: Task 2, Exploratory experimental studies: Single pellet tests; Rate mechanism analysis. Quarterly report, June 15, 1996--September 15, 1996

Abstract

Currently, the Morgantown Energy Technology Center, Department of Energy (DOE/METC) is actively investigating alternative hot fuel gas desulfurization sorbents for application to the Integrated Gasification Combined Cycle (IGCC). A sorbent must be highly active towards sulfur at high temperatures and pressures, and under varying degrees of reducing atmospheres. Also, it must regenerate nearly ideally to maintain activity over numerous cycles. Furthermore, regeneration must yield a sulfur product which is economically recoverable directly or indirectly. Several metal oxides have been investigated as regenerable sorbents for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot fuel gases. MnO was shown to have an intrinsic reaction rate approximately one order of magnitude greater than the rate or reaction with either CaO or ZnO and two orders of magnitude greater than the reaction rate with V{sub 2}0{sub 3}. Manganese also shows desulfurization potential in the temperature range of 600-700{degrees}C where metal oxides currently known to be reactive with H{sub 2}S are unsatisfactorily. In response to stability difficulties of single and binary metal oxide sorbents, increasing effort is being directed towards incorporation of an inert component into sorbent formulation as witnessed by the various Zn-titanates. Primarily, the inert component increases pore structure integrity while stabilizing the active metal oxide against reduction. This report will address testing of Mn-based sorbents in an ambient pressure fixed-bed reactor. Steady-state H{sub 2}S concentrations and breakthrough times will be presented.