Performance characterization of a novel Fe-based sorbent for anaerobic gas desulfurization finalized to high temperature fuel cell applications

Abstract A novel sorbent (SCX) composed of mixed iron oxides and hydroxides was studied to assess its suitability for H 2 S removal from biogas finalized to high temperature fuel cell systems. From an industrial point of view, the potential usage of this product would have a beneficial impact on operational costs, since it is less expensive than activated carbons. Moreover, it is a non-hazardous landfilled product with a reduced environmental impact and it can be easily regenerated. Sorbent SCX was tested in different operative conditions, evaluating the influence on sorption capacity of gas hourly space velocity (GHSV), gas composition (inlet H 2 S concentration, gas matrix, humidity), reactor temperature and filter geometry. As main outcomes, the experimentation highlighted: i) a hyperbolic increase in adsorption capacity as GHSV decreased, ii) a parabolic performance enhancement with increasing temperature and iii) a negative effect of humidity. Moreover, a comparison with commercial activated carbons typically used for the same purpose (Cu–Cr or KOH–KI treated) was performed, identifying the optimal operative parameters to obtain higher H 2 S sorption capacity for SCX sorbent. Specifically, SCX showed its potential in terms of H 2 S removal for GHSV lower than 330 h −1 , values of particular interest for many practical applications. In this case, an improved removal capability is obtained with respect to the ones exhibited by the considered carbons. Moreover, quantitative evaluations provided for unitary installed power (1 kW e fuel cell-based systems) highlighted the possibility to have more compact (volume reduction of about 50%) and cheaper (cost reduction up to six times) filters.