Natural nitrogen separation

Gas separation Hollow-fibre for high-volume applications with low-flux, low-selectivity membranes in which concentration polarisation is easily controlled (nitrogen from air) Spiral-wound when fluxes are higher, feed gases more contaminated, and concentration polarisation a problem (natural gas separations, vapour permeation). 

Natural nitrogen contains 0.365 percent N. Methods that have been used for separating N on a small scale are listed in Table 12.6. 

Other membrane-based gas-separation applications that developed in the late 1980s and the 1990s include the separation of carbon dioxide from natural gas, separation of organic vapors from air and nitrogen, and dehydration of air. Table 7.3 lists the major companies involved in the industry and their principal markets. Currently, total industry sales are estimated to be about US 200 million. Of all the industrial membrane-separation processes, gas separation is... 

Helium is separated from helium-bearing natural gases usually, but not always, in the process of removing nitrogen to improve the fuel value of the... 

The separation of nitrogen from natural gas reHes on the differences between the boiling points of nitrogen (77.4 K) and methane (91.7 K) and involves the cryogenic distillation of a feed stream that has been preconditioned to very low levels of carbon dioxide, water vapor, and other constituents that would form soHds at the low processing temperatures. 

Helium and Natural-Gas Systems Separation Helium is produced primarily by separation of hehum-rich natural gas. The hemim content of the natural gas from plants operated by the U.S. Bureau of Mines normally has varied from 1 to 2 percent while the nitrogen content of the natural gas has varied from 12 to 80 percent. The remainder of the natural gas is methane, ethane, and heavier hydrocarbons. 

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