13X Ex-Cu zeolite performance characterization towards H2S removal for biogas use in molten carbonate fuel cells

A 13X zeolite modified with Cu ions (13X Ex-Cu) by means of an innovative technique was employed as adsorbent for H2S removal from biogas, to obtain a desulfurized fuel suitable for molten carbonate fuel cell systems. Sorbent performance was characterized over a wide range of operating conditions typical of biogas mixtures (high H2S content - 200 and 1000 ppm(v); CH4 (60%)/CO2(40%) matrices) and compared to several conventional sorbents. A sensitivity performance analysis was conducted, varying parameters as space velocity, reactor temperature, gas matrix composition and particles size, finalized to identify the optimal conditions for the studied application. 13X Ex-Cu zeolite showed high potentiality for H2S uptake, specifically lowering space velocity, increasing reactor temperature and in presence of high methane concentration in the gas mixture, with adsorption capacity of 40 mg/g under specific and optimized conditions. By means of B.E.T. and XRD analyses, it was demonstrated that the obtained enhanced performance is due to the presence of a large amount of Cu2+ ions, guaranteed by the innovative synthesis procedure, able to realize an efficient physical-chemical adsorption mechanism. (C) 2018 Elsevier Ltd. All rights reserved.