Department of Chemical Engineering Seminar Series Distributed Ammonia Manufacturing

At the University of Minnesota, I have been working on designing a sustainable small scale Haber-Bosch process, powered by wind-generated electricity. The electricity generated by the stranded wind is used to split water to produce hydrogen, and to separate nitrogen from the air by pressure swing adsorption. Once produced, hydrogen and nitrogen are fed to a Haber-Bosch reactor to synthesize carbon-neutral ammonia. Our analysis of this small process shows that its performance is governed by three characteristic times: those for chemical reaction, for ammonia removal by condensation, and for unreacted gas recycle. As the process is currently operated, the reaction time is the largest of the three, thus the small process is currently controlled by the chemical kinetics. However, we have not focused to improve the reaction chemistry because a century of intensive effort to improve the catalyst has only resulted in minor improvements in the reaction kinetics. We have focused instead on designing a novel reactive-separation process that reduces the constraints of the reversible reaction.