Dense membranes for hydrogen separation and purification

Chapter 6 Dense Membranes for Hydrogen Separation and Purification..147... 

Tong, J., Matsumura, Y., Suda, H., and Haraya, K. Thin and dense Pd/Ce02/MPSS composite membrane for hydrogen separation and steam reforming of methane. Separation and Purification Technology, 2005, 46 (1-2), 1. 

An existing industrial application of the ultrapure hydrogen separated by dense Pd alloy membranes is for electronics industry. In the fabrication of silicon chips, hydrogen acts as a carrier to transport small quantities of vaporized chemical compounds required to "dope" the chip to the surface of the silicon wafer [Philpott and Coupland, 1988]. The hydrogen used must be of a very high purity. The membrane units are used not only for gas purification but also for hydrogen recovery from hydrogen>rich gas streams. 

Several gas purification technologies exist, but gas separation membranes have significant advantages in terms of simplicity, operating continuity, and efficiency [70]. Both dense and porous membranes may be used, but for hydrogen purification intended for fuel cells, the dense membranes are receiving the most attention as the purified hydrogen gas is virtually pollutant free [71]. 

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