Eiichi Kikuchi

Reverse-selective microporous membrane for gas separation.

Reverse-selective membranes, through which bigger molecules selectively permeate, are attractive for developing chemical processes utilizing hydrogen because they can maintain the high partial pressure of hydrogen required for their further downstream utilization. Although several of these chemical processes are operated above 473 K, membranes with outstanding reverse-selective separation performance at these temperatures are still to be reported. Herein, we propose a new adsorption-based reverse-selective membrane that utilizes a Na cation occluded in a zeolitic framework. The membrane developed in this work, a compact Na(+)-exchanged ZSM-5 (NaZSM-5) type zeolite membrane, enables us to selectively permeate and separate bigger polar molecules, such as methanol and water, from a stream containing hydrogen, above 473 K. On the other hand, a Na(+)-free, H(+)-exchanged ZSM-5 (HZSM-5) type zeolite membrane did not show separation properties at these temperatures. The microporous zeolite membrane developed in this study can be applied to a variety of chemical reaction systems to minimize energy consumption.

Review on Prospects for Energy Saving in Distillation Process with Microporous Membranes

Abstract This review describes prospects for energy saving in the chemical and petroleum industries and recommends that increasing efforts be exerted on the development of membrane-based separation systems. A preliminary estimate suggests that the simple addition of a membrane separation unit to an existing separation system or distillation unit can drastically reduce energy consumption by more than 70%. This review also describes state-of-the-art of zeolite-based separation membranes, which is the one of the most promising technologies among emerging separation methods.