High-Temperature Membrane for Water Removal in in-Situ Process

Abstract

Water is a main by-product of many chemical processes, such as the production of hydrocarbons from synthesis gas, condensation reactions, and oxidative dehydrogenation. In most cases, water must be removed before or during product purification. Current water removal technologies, including direct condensation, azeotropic distillation, and vacuum or reactive distillation, are energy intensive. We are investigating use of in-situ water removal membranes to circumvent the energy-intensive conventional approaches for separating water at low temperatures and pressures. The water removal membranes would provide a continuous flux of water at constant temperature and pressure while avoiding the energy-consuming steps of conventional separation methods. Large energy losses associated with water removal could be avoided, and process efficiency significantly improved. Water is undesirable as a primary by-product at the reaction site because it could lower the reaction rate by decreasing the catalyst activity. Removal of water at the reaction site, therefore, can prevent catalyst deactivation, and it also can increase the reaction yield by shifting the equilibrium conversion to the desired products. Because the existing polymer-based membrane technologies have a temperature limitation, we are developing ceramic membranes for separating steam under process conditions over a wide temperature range (200-900ºC). Preliminary results of the steam permeation rate measurement with dense ceramic membranes made of ionic conductor will be presented in this talk.