Method and apparatus for removing trace impurities from a gas using superactivated carbon material

摘要

Trace impurities such as organic compounds and carbon monoxide are reduced to sub-ppb levels in gases such as nitrogen, helium and argon, by gas purifying systems that contain an ultra-low emission (ULE) carbon material. Ultra-low emission (ULE) carbon materials can be made from commercially available carbon materials in the form of pellets, extrudates and beads and is capable of removing impurities from a gas stream down to parts-per-billion (ppb) and sub-ppb levels without concurrently emitting other impurities such as moisture or carbon dioxide to the purified gas stream. The carbon material is superactivated by heating the carbon to temperatures from 300° to about 800° degrees C. in an ultra-dry, inert gas stream. The ultra-low emission (ULE) carbon material is handled and stored in an environment that minimizes contamination from moisture and other oxygenated species in order to maintain its ppb and sub-ppb impurity removal and low emission properties. The ultra-low emission (ULE) carbon material can be used as "stand-alone" purifier material or in combination with other scavenging materials that are capable of removing large quantities of impurities such as oxygen and moisture that are not removed or only marginally removed by the ultra-low emission (ULE) carbon material.