A Novel Energy-Efficient Process for Production of Nitrogen from Air via a Reaction-Driven Membrane Reactor

Gaseous nitrogen has a wide variety of applications in industry. Currently, nitrogen is produced by energy intensive cryogenic fractional distillation of liquefied air, pressure swing adsorption (PSA), and membranes. In this paper, a novel process was proposed and experimentally verified for production of nitrogen. In this process, oxygen in air is extracted through a dense oxygen-permeable membrane, which is then reacted with methane. By optimizing the air and methane flow rate, the process can produce nearly pure nitrogen as well as a syngas (a mixture of CO and H-2). At 800 degrees C, the reactor produced nitrogen at a rate of 9.2 mL cm(-2).min(-1) with purity over 99%, and methane was reformed to syngas with CH4 throughput conversion over 90%, H-2 selectivity of 92%, and CO selectivity of 92%. The syngas can be burned to generate heat or used as intermediate chemicals for production of liquid fuels and hydrogen. Since the membrane reactor is driven by the energy released by the reaction and does not consume high grade energy electricity, it has a much higher overall energy efficiency than the current industrial nitrogen separation processes.