Catalytic transformation of H2S for H2 production

Hydrogen sulfide (H2S) gas is a by-product from natural gas refining, hydrodesulfurization of various fossil fuels, and syngas cleaning from pyrolysis and gasification. Catalytic pyrolysis of H2S provides an alternative and effective pathway to recover both H-2 and sulfur. Catalysts from hydrotalcite of Zn-Al, Zn-Ni-Al, and Zn-Fe-Al were employed for H2S pyrolysis and compared with TiO2 and MoS2 at atmospheric pressure and temperatures in the range of 923-1123 K. Kinetic analysis was carried out in a packed bed reactor which revealed the effect of H2S partial pressures to be of the order of 0.8-1 with respect to H2S. The developed novel catalysts showed improved performance with significantly reduced activation energy compared to TiO2 by 30 kl/mol as well as higher H2S conversion during pyrolysis (17% at 1173 K) than with MoS2 catalyst, even at high H2S partial pressure which is necessary for viable hydrogen production. The new approach showed an alternate economical and efficient pathway of catalyst design to obtain high activity and stability for simultaneous H-2 energy and pure sulfur recovery from unwanted H2S resources. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.