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

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.