초록

High-purity nitrogen is recovered from combustion gas such as exhaust stack gases, by utilizing selective gas-permeable membranes to separate by rejection, nitrogen from the other gases present in the gas stream.

대표청구항 ▼

A process for the production of nitrogen, which comprises: (a) combusting a carbonaceous fuel to form a combustion gas comprising nitrogen, carbon dioxide, and oxygen; (b) treating the combustion gas to remove to the extent present particulates, the oxides of sulfur, and the oxides of nitrogen and c

A process for the production of nitrogen, which comprises: (a) combusting a carbonaceous fuel to form a combustion gas comprising nitrogen, carbon dioxide, and oxygen; (b) treating the combustion gas to remove to the extent present particulates, the oxides of sulfur, and the oxides of nitrogen and compressing the treated gas stream with or without water condensation in one or more stages of compression to a pressure sufficient to enable membrane separation of molecular nitrogen from carbon dioxide and oxygen; and (c) contacting the compressed, treated gas stream at a temperature of from about 70°to about 160°F. with at least one membrane preferentially selective to reject nitrogen to yield a permeate comprising carbon dioxide and oxygen and a residue concentrated in nitrogen, said membrane having an oxygen and/or carbon dioxide-to-nitrogen ratio of permeability of from about 2.0 to about 20.0 and there is formed a nitrogen enriched gas stream containing at least 90% by volume nitrogen and no more than about 1 to about 5% by volume oxygen.