A novel process of CO2 reduction coupled with municipal solid waste gasification by recycling flue gas during co-disposal in cement kilns

Waste-to-energy is one of the most effective methods to save energy and reduce carbon emissions in the cement industry. In this study, a novel process of CO2 reduction coupled with municipal solid waste gasification by recycling flue gas during co-disposal in cement kiln is proposed. The model of MSW gasification by recycling flue gas is developed in Aspen Plus based on Gibbs free energy minimization. Meanwhile, the techno-economic-environmental analysis of the proposed process is also evaluated via taking clinker production capacity of 5000 tones/day as the objective. Results indicate that the low heating value of syngas, the cold gasification efficiency, and total exergy efficiency are respectively 4.42 MJ/m3, 91.96%, and 82.33%, indicating a high energy conversion efficiency is obtained during MSW gasification by recycling flue gas from cement kiln. Moreover, the net present value, internal rate of return, and payback period of the proposed process are in sequence as 86.73 M$, 82.21%, and 2.67 years, assuming the coal price is 150 $/ton. The proposed process can reduce about 172.11 kg eq.CO2/ton clinker compared to the traditional cement clinker generation.