GB1061393A - Separation of nitrogen from air - Google Patents

Abstract

Pure N2 is obtained by burning air with a fuel such as natural gas to give a mixture of N2, CO2 and H2O, and absorbing the CO2 and H2O in a solution which is regenerated by direct introduction of hot gaseous combustion products, and then recycled. In Fig. 1 (not shown) compressed air and fuel burn in pipe 15 which extends into water in vessel 16, maintained at 35 p.s.i.g. Gaseous products enter the bottom of packed tower 20, and a 10% solution of monoethanolamine at 100 DEG F. is fed to the top. N2 is withdrawn at 22 and dried with SiO2 gel or Al2O3. The solution containing CO2 and H2O is removed via heat exchanger 24 to stripper 26 where it is heated by the products of burning air and fuel in submerged burner 29, and gases are exhausted at 32. Regenerated solution is passed via heat exchangers 24 and 37 to tower 20. In a modified tower 201 (Fig. 2, not shown), gases enter at 38, regenerated solution at 39, and fresh solution at 40, and the combined solutions are removed at 42.ALSO:The solution used to absorb CO2 and H2O from a gaseous mixture with N2 is regenerated by direct introduction of hot gaseous combustion products. In Fig. 1 (not shown), compressed air and fuel burn-in pipe 15 which extends into water in vessel 16, maintained at 35 p.s.i.g. The gaseous products (N2, CO2 H2O) enter the bottom of packed tower 20, and a 10% solution of monoethanolamine at 100 DEG F. is fed to the top. N2 is withdrawn at 22 and dried with SiO2 gel or Al2O3. The solution containing CO2 H2O is removed via heat exchanger 24 to stripper 26 where it is heated by the products of burning air and fuel in submerged burner 29, and gases are exhausted at 32. Regenerated solution is passed via heat exchangers 24 and 37 to tower 20. In a modified tower 20\sv (Fig. 2, not shown), gases enter at 38, regenerated solution at 39, and fresh solution at 40, and the combined solutions are removed at 42.