Evaluation of gaseous emissions from thermal conversion of a mixture of solid municipal waste and wood chips in a pilot-scale heat generator

Abstract The objective of this study was to develop a novel pilot-scale system that combines pyrolysis and combustion processes, fed by a mixture of municipal solid waste (MSW) and wood chips (WC). The pyrolysis of MSW+WC (1:1) produces char and volatiles as fuels, which just the pyrolysis gas was used in a post-combustion chamber for heat generation. The gases evaluated were carbon monoxide (CO), nitrogen oxides (NO x ), sulfur dioxide (SO 2 ), BTEX (benzene, toluene, ethylbenzene and xylene) and polycyclic aromatic hydrocarbon (PAHs). Initially, the pyrolysis was performed by laboratory experiments and the physicochemical characterization of MSW+WC. The MSW+WC showed a heating value of 23.93 MJ kg −1 , which is higher than several bioenergy crops reported. The pyrolysis and post-combustion process were found to minimize the generation of hydrochloric acid (HCl), dioxins and furans as well as the volatile compounds. The gases concentrations emitted were (mg Nm −3 ): 35.83 of CO, 24.37 of SO 2 , 106.84 of NO x , and 4.88 × 10 −3 of BTEX, with a low PAH content. These values are below the legal emission standards established by United States Environmental Protection Agency (US EPA), Danish Environmental Protection Agency (Danish EPA), German Federal Emission Control Regulations (17.BlmSchV) and National Council for the Environment of Brazil (CONAMA 316/02).