Investigation into the interaction of biomass waste with industrial solid waste during co-pyrolysis and the synergetic effect of its char gasification

Abstract

In this work, the interaction between waste cypress sawdust (WCS) and coal liquefaction residue (CLR), a type of industrial solid waste, during co-pyrolysis was studied by thermogravimetry-mass spectrometry (TG-MS) and pyrolysis-gas chromatography mass spectrometry (Py-GC/MS). The gasification reaction characteristics of co-pyrolysis char were also evaluated. The results showed that both promoting and inhibiting effects existed in the co-pyrolysis process of WCS and CLR. When the pyrolysis temperature was less than 420 °C, the catalysis of minerals was conducive to the pyrolysis reaction. At higher temperatures, the polycondensation and carbonization produced by the interaction between the components inhibited the release of volatiles. The gasification reactivity of co-pyrolysis char was better than that of individual WCS and CLR chars. The synergistic effect was most obvious when the blending ratio of WCS to CLR was 3:1. In the gasification process of co-pyrolysis char, the WCS component with better reactivity preferentially reacted to form an abundant pore structure, which exposed more reactive sites and promoted the diffusion and mass transfer of gasification agent. Moreover, alkali and alkaline earth metal species in WCS and iron bearing minerals in CLR can catalyze the gasification reaction, contributing to the synergistic effect. Therefore, the addition of a suitable solid waste to biomass waste can improve the energy efficiency and simultaneously achieve solid waste utilization.