Economic feasibility of silica and palladium composite membranes for industrial dehydrogenation reactions

Abstract

This article addresses the economic feasibility of silica and palladium composite membranes for gaseous dehydrogenation reaction schemes. Unlike other methodologies addressed so far, this work presents the economic assessment of dehydrogenation reaction schemes using a conceptual design based simulation methodology for the comparative economic assessment of membrane reactors with conventional reactors. The suggested methodology is applied to two industrially prominent reaction schemes namely styrene (from ethylbenzene) and propylene (from propane) production using silica and palladium composite membrane reactors. Various sub-cases studied in this work include the influence of membrane area per reaction zone volume, reaction zone temperature, reaction and permeation zone pressure, membrane thickness and sweep gas flow rate on process economics. Based on this work, the propylene production scheme is evaluated to provide 60–70% excess profits using membrane reactors when compared with the conventional reactor based technology. However, the gross profit profiles for both conventional reactor and membrane reactor configurations have been found to be similar for styrene production case. For all cases, the cost contribution of membranes and other auxiliary equipment is estimated not to exceed 20% of the total costs. In addition, similar economic performance has been observed for both silica and palladium membranes. Based on these studies, it has been concluded that the industrial applicability of membrane reactors is economically suitable for those dehydrogenation reactions that enable significant conversion enhancement with respect to the conventional reactor technologies.