Design of a waste to energy process using steam gasification

Abstract

The past few years faced a sharp increase in plastic and biomass wastes. This rise has created many challenges about how to manage and process these wastes to useful products. Syngas, which is a mixture of hydrogen H2 and carbon monoxide, is a clean alternative to fossil fuels for energy recovery. For syngas production, various types of plastics and biomass wastes can be used through gasification processes. For this reason, this report presents first a summary of recent works on syngas production from different biomass and plastic wastes feedstock. It focuses basically on the steam gasification type. However, the gasification process was found to be associated with many challenges. It is primarily associated with high formation of tars and char. For this reason, some simulations on HSC software will be addressed in order to improve the gasification process. Cogasification has been proposed as one of the best techniques to optimize the produced syngas. It can promote and optimize syngas production over char and tars. This thesis focuses on a thermodynamic study on HSC software to show the effect of several parameters on product composition and mainly steam to carbon (S/C) ratio. Moreover, synergism effect is discussed as well during the cogasification. All in all, cogasification is a promising technique for maximum energy recovery from syngas. It allows for a higher yield of syngas with minimum tar formations. This step seems to hold a promising future for waste treatment and management.