Method for water removal from corrosive gas streams

Abstract

A process and apparatus for the removal of water from corrosive halogen gases, particularly chlorine- or bromine-containing gases, down to .ltoreq.100 ppb water concentration are described. The critical component is a high silica zeolite, preferably high silica mordenite, which in a variety of physical forms is capable of dehydrating such gases to .ltoreq.100 ppb or .ltoreq.50 ppb without being detrimentally affected by the corrosive nature of the gases in the presence of water. The high silica zeolite is produced by the removal of alumina from a natural or synthetic zeolite while retaining the desirable zeolite structure, to a silica:alumina ratio of from 20-2000:1. Metal cations which may be depleted by the alumina removal may be replaced by solution impregnation. Halogen- or halide-containing gases, or those with equivalent corrosion properties, may be dehydrated without deterioration of the high silica zeolite. The high silica zeolite is retained in a corrosion-resistant container which is installed in a gas supply line, such as to a gas- or vapor-deposition manufacturing unit. The invention provides final dehydration to corrosive halogen gas streams intended for gas- or vapor-deposition formation of high purity electronic, optical, prosthetic or similar products, and can be used in combination with upstream preliminary dehydration process and/or solid particulate removal units.

Dependencies are inferred from the claim text.