A two-step process for removal of carbon dioxide and production of desalinated water using ammoniated saline water

Abstract

The emission of CO2 has been increasing steadily and reached the critical concentration of 400 ppm in 2013 for the first time. CO2 removal from the sources such as fossil-fuel power plants and similar sources is of paramount importance to these industries and to reduce the effect on global warming. A two-step process is investigated experimentally to remove CO2 from a synthetic mixture of natural gas containing it. The first-step of the process is based on the modified Solvay process and involves the chemical reaction between CO2 and ammonia in saline solution. This process can reduce CO2 by about 99% and at the same time reduce water salinity by 40%. The process produces sodium bicarbonate and ammonium chloride which is at high concentrations. The second step uses a membrane extraction method to reduce the concentration of ammonium chloride to produce treated water that can be used for irrigation purposes. This combined process is potentially more effective and less harmful than the conventional amine scrubbing process. This innovative process has been applied to the sweetening of natural gas in the laboratory that can be extended to similar sources. Simultaneous reduction of salinity to produce treated water is an additional benefit.