Recycling municipal solid waste utilizing gasification technology: a case study

Reliable, affordable, and clean energy supply is of considerable importance for the society, economy, and the environment. Renewable energy sources can provide several times the world’s energy demand. Biomass energy is considered a promising clean energy option for the reduction in greenhouse gas emissions and energy dependency. Among feasible technologies, biomass gasification has been considered as an enabling technology for municipal solid waste (MSW) conversion systems. The synthesis gas produced in waste-to-energy gasification of MSW can lead to their increased role in electricity generation in the future and reduces waste disposal costs. In this study, a thermodynamic equilibrium model was developed based on the downdraft fixed-bed gasifier to evaluate the effect of waste moisture content on synthesis gas composition. Besides, the equilibrium temperature of the gasifier and heating value of synthesized gas from the downdraft fixed-bed gasifier have been analyzed. Municipal solid waste of Tehran is considered as the main feed of the proposed system. The modeling results showed reasonable agreement with the experiment. The effect of operating condition on fuel moisture content and gasifier temperature was investigated. The effect of fuel moisture content on syngas compositions was also studied. The hydrogen content in the synthesis gas composition increases slightly initially to 17.9% (in moisture content 18%) but then starts reducing again. Besides, the effect of reactor temperature on synthesis gas composition was investigated.