Study on the pollutant emission characteristics of the co-combustion of high S/Cl waste mixed with recycled papermaking waste

Abstract

Using solid waste to replace coal for power generation is one of the effective ways to reduce CO2 emissions, but the incineration of some high-sulfur and high-chlorine solid waste will lead to the increase of pollutant emissions. This paper proposed a new way to self-control pollutant emissions by co-incinerating different solid wastes with specific properties. In this work, the recycled papermaking waste residue (RPR) and sludge (RPS) with high calcium content were chosen to co-combustion with high-sulfur and high-chlorine solid waste, and the emission characteristics and control mechanism of pollutants under co-combustion were explored. The primary calcium compound in the recycled papermaking solid waste was CaCO3. When RPR and RPS were mixed at a ratio of 1: 1, HCl could be fully captured, resulting in the least emissions. Pollutant emissions was controlled by adding RPR and RPS to high-sulfur textile dyeing sludge and polyvinyl chloride. The sulfur-fixing efficiency rose from 65 % to 91 % and the chlorine-fixing efficiency rose from 69 % to 93 % with an increase in Ca/(S + 0.5Cl) from 1 to 3. As the reaction temperature rose from 700 °C to 1000 °C, the sulfur-fixing efficiency and chlorine-fixing efficiency initially increased and subsequently dropped. The CaCO3 in the material was rapidly decomposed at 800 °C, which accelerated the positive reaction rate with SO2 and HCl, so that the sulfur-fixing efficiency and chlorine-fixing efficiency reached the maximum, which were 89 % and 92 %, respectively. CaSO4 and CaClOH were the principal reaction products at the temperature range of 700 °C to 1000 °C.