Thermogravimetric characteristics and combustion emissions of rubbers and polyvinyl chloride in N2/O2 and CO2/O2 atmospheres

► Understanding the rubber and plastic combustion in CO2/O2 is novel. ► Combustion characteristics between different materials were compared. ► Replacement of N2 by CO2 decreased the reactivity of the samples. ► Effects of heating time, temperature, atmosphere on emissions were studied. ► Replacement of N2 by CO2 reduced NOx or SO2 emissions at some temperatures. The thermogravimetric characteristics of tire rubber (TR), rubber mattress (RM) and polyvinyl chloride (PVC), representing the rubber and plastic materials of municipal solid waste (MSW) were compared under 80N2/20O2 and 80CO2/20O2 atmospheres. Replacement of N2 by CO2 reduced the weight loss rate of most peaks below 600°C, postponed the location of the peaks above 600°C, and resulted in less complete burnout, which indicated the combustion in CO2/O2 atmosphere decreased the reactivity of the samples. The emissions of TR, RM and PVC combustion in a tube reactor were analyzed by a flue gas analyzer. The concentrations of CO, H2, SO2 and NOx all increased initially and decreased afterwards along with the heating time. During 800–1000°C, NOx and SO2 emissions of all samples increased by the temperature, and decreased by the replacement of N2 by CO2. In both atmospheres, the subsequence of the NOx emission was TR>RM>PVC, and the subsequence of the SO2 emission was TR>PVC>RM. The effects of temperature and atmosphere on the CO and H2 emissions of two rubbers were different from those of PVC.