Comparison of two methods of iridium impregnation into HZSM-5 in the methanol to propylene reaction

In this paper, the effects of two methods of iridium impregnation into HZSM-5 on catalyst stability, selectivity for propylene and byproducts in the conversion of methanol to propylene (MTP) were investigated in a continuous flow isotherm fixed-bed reactor. XRD, BET surface area, NH(3)-TPD and ICP-AES analytical techniques were applied to define the physical and chemical characteristics of zeolites. The reaction was conducted at 480 degrees C and 1 bar with WHSV = 1 h(-1), and with an equal weight percent of methanol and water in the feed. The results revealed that iridium impregnation into HZSM-5 powder led to enhanced propylene selectivity (8%) and catalyst stability while iridium impregnation into extruded HZSM-5 drastically decreased catalyst lifetime. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.