IM-5 zeolite for steam catalytic cracking of naphtha to produce propene and ethene. An alternative to ZSM-5 zeolite

Steam catalytic cracking of naphtha in smaller FCC units can be considered an option to produce more ethene and propene. These units will operate at high reaction temperatures and in the presence of steam. The profitability of these units could be improved with the use of new catalysts with higher activity and hydrothermal stability, without compromising the selectivity to light olefins. We have explored the possibilities of IM-5 zeolite for high temperature steam catalytic cracking (SCC) of a naphtha, as an alternative to commonly used ZSM-5 zeolite. So, we compare the catalytic activity, the effect of operating variables of the process and the yields of interest products between the two zeolites, the IM-5 zeolite and the best of ZSM-5 zeolites studied previously for SCC reaction. Furthermore, we study post-synthesis treatment of zeolite with phosphorous containing precursors to enhance the hydrothermal stability, and the effect of it on the catalytic activity and the yield of products. It can be seen as the use of the zeolite proposal improve the catalytic activity with respect to the best of ZSM-5 zeolite in SCC process, without compromising the yield to products of interest. Furthermore, the incorporation of phosphorous has a large effect on hydrothermal stability of zeolite, showing this zeolite as an important competitor to the ZSM-5 zeolite for steam catalytic cracking of naphtha.
Financial support by the Ministerio de Ciencia e Innovacion of Spain (MICINN) [Programa Nacional (Project MAT2006-14274-C02-01) and Programa Consolider-Ingenio 2010 (Project MULTICAT)] is gratefully acknowledged.