Sulfur Poisoning and Tolerance of Methanol Synthesis Catalysts

Abstract

Summary A series of CuO / ZnO / AI2O3 catalysts with different Cu/Zn ratios were tested for methanol synthesis activities to evaluate sulfur poisoning and tolerance by pulsing H2S. Their steadystate activities and sulfur contents were compared with those of commercially poisoned catalysts. The reason for the lower sulfur tolerance of commercially poisoned catalysts relative to catalysts poisoned under laboratory conditions and some insights related to poison mechanism are discussed. XRD and SEM examinations indicate that most of the sulfur is taken up in the forms of zinc sulfide and sulfate in the methanol catalysts accounting for the beneficial effect of ZnO-rich catalysts on sulfur tolerance. The finding of a subsulfate of Cu and Zn (e.g. Cu1.5ZnSO4(OH)3) suggests that the copper is also attacked by sulfur under certain conditions.