Catalytic pyrolysis-gasification of contaminated municipal wastes: Catalyst regeneration

The aim of this work is to investigate the effect of the catalyst regeneration during thermo-catalytic conversion of municipal solid waste and municipal plastic waste by pyrolysis-gasification. Ni/ZSM-5 catalyst was used to affect the product yields and composition for 10 cycles in the pyrolysis-gasification reaction. The Ni/ZSM-5 catalyst was tested without regeneration, however, to investigate the effect of catalyst regeneration, the Ni/ZSM-5 catalyst was also regenerated after each use. The composition of the gas products was analysed by GC-FID and GC-TCD methods, where the concentration of hydrogen, carbon-monoxide, carbon-dioxide, methane and other volatile hydrocarbons had been detected and changes was discussed. Regarding the pyrolysis oil, the single ring and polyaromatic content had been analysed by HPLC. The surface properties and the morphology of the used catalyst was also studied to follow the catalyst deactivation. Based on the results, the BET surface of the used catalyst decreased by 31.0% through the consecutive repeated applications, when municipal solid waste was utilized and the catalyst was not regenerated. However, it decreased only by 16.2% when the catalyst was regenerated between the repeated applications. When municipal plastic waste was pyrolyzed, the decrease were 15.3% and 8.0%, respectively. In order to compare the main properties and the effects of the regenerated and non-regenerated catalysts during the pyrolysis-gasification process, a comparative analysis was made, while a SWOT analysis was studied on the step of regeneration. • MSW and MPW were investigated in pyrolysis-gasification with Ni/ZSM-5 in 10 cycles • Regeneration of the catalyst can maintain the activity high for a longer period • Raw material has a great effect on the products and catalyst activity • The yields of the generated synthesis gas and single ring aromatics were analysed • The feasibility of regeneration was considered by comparative- and SWOT analysis