Influence of low-temperature pyrolysis pretreatment on the co-combustion performance of coal and waste polyvinyl chloride/tire

Co-combustion of coal and municipal solid waste (MSW) is an effective method to utilize MSW and reduce CO2 emission from coal-fired power plant. However, several undesired properties of MSW (such as poor homogeneity, poor grindability, high moisture content, high chlorine content) limits the extensive application of cocombustion technology. In this study, the low-temperature pyrolysis pretreatment of typical MSW (PVC/tire) was innovatively proposed before co-combustion with coal. The H/C atomic ratio of PVC char and tire char was similar to common sub-bituminous coal and bituminous coal. After pyrolysis, large amounts of chlorine and sulfur were eliminated from PVC and tire. The graphitized structure of PVC was formed whereas the graphitized structure of tire was weakened. The ignitability, burnout characteristics and combustion reactivity of coal were improved after the addition of PVC, tire, PVC char and tire char. The comprehensive combustion characteristic index of various mixtures was also increased after pyrolysis. The highest comprehensive combustion characteristic indexes of PVC char and tire char were obtained at 325 degrees C and 350 degrees C, respectively. Obvious synergistic effects among the individual components were observed during co-combustion. The activation energy of coal was greatly decreased after the addition of PVC, tire, PVC char and tire char.