Conversion of low-rank coal and sewage sludge into syngas for H2SO4 production and straw hydrolysis.

Abstract

This study investigates the potential of using sewage sludge and low-rank coal for the sustainable production of sulfuric acid, which can then be used for the hydrolysis of straw through ASPEN PLUS simulation. Pyrolysis and gasification processes were used to convert sewage sludge and low-rank coal into syngas, which were then purified and oxidized to produce H2SO4 and NH3 gas. The pyro-gasification enhanced syngas yield. The effects of key process parameters such as temperature, steam-to-biomass ratio, equivalence ratio, and feedstock composition on the yield and composition of syngas and H2SO4 coupled with minor parameters like pressure were investigated. The simulation was conducted over the temperature and pressure range of 400 - 900°°C and 70 - 150kPa respectively. While the steam-to-biomass ratio and equivalence ratio were respectively varied from 0.66 - 1.65 and 0.14 - 0.35. Part of the 1012.88kg/h of H2SO4 produced was used to hydrolyze straw, producing glucose as a valuable feedstock for biorefineries. About 3989.10kg/h of NH3 was produced. Results showed that the use of sewage sludge and low-rank coal as feedstocks for syngas production can be a sustainable and cost-effective alternative to traditional fossil fuels. The resulting H2SO4 can also be used for various other applications, such as in the production of fertilizers and detergents. Overall, this study agrees with the literature, demonstrates the potential of integrating biomass and waste resources for the sustainable production of high-value chemicals and fuels, and contributes to the field of sustainable chemical and energy production while addressing environmental and economic considerations.