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

摘要

This paper presents detailed study of biogas reforming. Model biogas with different levels of H_2S is subjected to reforming reaction over supported Ni catalyst in a fixed bed reactor at 700 ℃ and 800 ℃. In order to understand the poisoning effects of H_2S the reactions have been initially carried out without H_2S in the feed stream. Three different H_2S concentrations (20, 50 and 100 ppm) have been considered in the study. The H_2O to CH_4 ratio is maintained in such as way that CO_2 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 H_2S from the feed stream ⅱ) temperature enhancement and ⅲ) steam treatment. Poisoning at low temperature is not recoverable just by removal of H_2S from the feed stream. However, poisoning at high temperature is easily reversed just by removal of H_2S from the feed stream. Unlike some previous reports by Li et al. (2010) and Rostrup-nielsen (1971) , catalyst regeneration is achieved in shorter time frames for all the regeneration techniques attempted.