High Gas Purification Research Articles

Progress and perspectives in high-purity substance production for semiconductor industry

Abstract In the last decade, novel approaches for post-synthesis processes of separation and high purification of gases are gaining larger acceptance in industry. The market is competing with consolidated operations such as cryogenic distillation. The key for new approaches of distillation, membranes and crystallization in challenging and harsh environments is the development of new tough, high-performance materials that are characterized by higher energy efficiency compared with conventional cryogenic distillation. This review highlights the most promising fields of research in high purification and separation of gases by considering the elevated pressure and thermal distillations, membrane cascades, purification in synthesis by use of catalytic technologies, crystallization and hydride methods based on them.

High purification of gases for removal of highly permeable impurities in membrane units comprised of two or three in-series modules

A mathematical model of the process of gas purification to remove highly permeable impurities with a low concentration in membrane units composed of two or three in-series modules has been considered. Expressions have been obtained for the degree of separation defined as the ratio of the impurity concentration in the feed gas to that in the retentate. The degree of separation depends on the recovery of impurities, membrane area ratios in the modules, and the effective selectivity.

High purification of gases by the hybrid gas hydrate-membrane method

A combination of membrane separation with gas hydrate crystallization has been proposed for enhancing the efficiency of separation and purification of gass. A mathematical model of a hybrid gas hydrate-membrane method has been derived. The results of calculation of the degree of separation by this method for different process conditions are presented. It has been shown that the use of gas hydrate crystallization in membrane technology can preclude the concentration of impurities in the high-pressure compartment of a membrane element and thereby significantly improve the gas separation and purification efficiency.

Ultrapurification of gases in a continuous membrane column cascade

The high purification of gases from easily penetrating impurities by a cascade of a continuous membrane column type has been investigated experimentally and theoretically. The equations for the separation power of cascades in the case of high purification of gases from low level impurities has been obtained. The efficiency of a continuous membrane column cascade is compared with exergetic efficiency of a multistage symmetric cascade in the case of non-mixed flows at different concentrations.