Modelling, simulation and optimization of a solid residues downdraft gasifier: Application to the co-gasification of municipal solid waste and sugarcane bagasse

摘要

This work modelled a downdraft gasifier with air in the co-gasification of municipal solid waste (MSW) and sugarcane bagasse using a kinetic, one-dimensional and steady state approach. A central composite design was carried out to assess the impact of the co-gasification ratio (CGR), defined as the MSW mass fraction in the feeding biomass, the biomass moisture content and the equivalence ratio. As a result, polynomial models were obtained for syngas composition, lower heating value (LHV), energy efficiency and sum of CO and H_2 molar fractions on wet basis. The models were considered robust since the coefficient of determination R~2 ranged from 0.96082 to 0.99345. The impact of each chosen factor was investigated to maximize the energy efficiency and the sum of CO and H_2 molar fractions. The optimal case, with CGR 50%, a biomass moisture of 5.0% and an equivalence ratio of 0.18, resulted in a syngas molar fraction of 3.63, 30.51, 7.53, 19.76 and 0.77% for H_2O, CO, CO_2, H_2 and CH_4, respectively, corresponding to a LHV of 6.74 MJ/Nm~3 and an energy efficiency of 39.93%. By the end, the process showed great potential to produce a syngas rich in CO and H_2.