Helium high purity, recovery

For gas separation membranes, for example, He, O2, and N2 gas transport properties of CA/poly(methyl methacrylate) (PMMA) blends have been measured [108]. This article reported that CA/PMMA blends exhibited phase separation with limited intermiscibility between the components, but they were possibly useful as membrane materials to produce high-purity helium gas streams combined with high helium recovery. 

Neon and helium accumulate in the condenser of the high pressure column. They can be purged from the system from time to time and sent to a separate purification unit for recovery of neon from nitrogen and helium. The purification involves adsorption and distillation to obtain a high purity neon. The quantity of helium produced in this way is too small to be economically attractive and it is discarded. Neon is produced with a very high purity. 

Helium or nitrogen may be used as the carrier gas with packed columns and excellent recoveries of triacylglycerols have been obtained with both, although the former is to be preferred when feasible, as better resolutions are attainable at high flow-rates. Nitrogen is used most often for reasons of cost, but it is essential that it be of very high purity as traces of oxygen or water will destroy liquid phases at elevated temperatures. 

Helium occurs naturally as a minor constituent (<5%) of some natural gas streams. It is usually recovered by a two-sicp process the first recovers a crude helium concentrate (about S0%) from the natural gas, and the second purifies the helium to a high purity product (>99.99% for Grade A Helium). Several hybrid proce.sses for accomplishing both steps of the helium recovery and purification operation have been evaluated by Choe et al. (1988). 

All industry relies on the recovery of natural resources, and the cryogenic industry is no exception. For instance, helium, critical to the cryogenic industry, is a very limited natural resource. It is found as a minor component in some natural gas supplies of Kansas, Texas, Wyoming, and Arizona and would normally be wasted, vented to the atmosphere from gas burners. Since 1917, the U.S. Bureau of Mines has separated helium from natural gas. The early use of the high-purity helium was primarily in noncryogenic gaseous... 

---