Deactivation and regeneration of Ni catalyst during steam reforming of model biogas: An experimental investigation

•Reforming of biogas containing H2S on Ni catalyst is experimentally investigated.•Catalyst deactivation investigated for 20, 50, and 100 ppm H2S at 700 and 800 °C.•Catalyst regeneration attempted by three different techniques.•Faster regeneration times than previous reports are observed.•Sulfur saturation coverage is independent of H2S concentration at low temperature.

This paper presents detailed study of biogas reforming. Model biogas with different levels of H2S is subjected to reforming reaction over supported Ni catalyst in a fixed bed reactor at 700 °C and 800 °C. In order to understand the poisoning effects of H2S the reactions have been initially carried out without H2S in the feed stream. Three different H2S concentrations (20, 50 and 100 ppm) have been considered in the study. The H2O to CH4 ratio is maintained in such as way that CO2 also participates in the reforming reaction. After performing the poisoning studies, regeneration of the catalyst has been studied using three different techniques i) removal of H2S from the feed stream ii) temperature enhancement and iii) steam treatment. Poisoning at low temperature is not recoverable just by removal of H2S from the feed stream. However, poisoning at high temperature is easily reversed just by removal of H2S from the feed stream. Unlike some previous reports by Li et al. (2010) and Rostrup-nielsen (1971) [1,2], catalyst regeneration is achieved in shorter time frames for all the regeneration techniques attempted.