The Migration Pattern of Chlorine during Co-pyrolysis Process for Herb Residue and Coal

Abstract Taking coal and herb residue as the research object, the thermal analysis of chlorine in the mixture of coal and herb residue was studied by dual-temperature tube furnace. Comparing the distribution of chlorine in solid, liquid as well as gases produced during pyrolysis, it could be seen that when the pyrolysis temperature and the sample ratio changed, the distribution of chlorine in the solid and gas phases varied greatly, but the change in the liquid phase was little. Their ranges of variation were 23.35%, 6.05% and 17.29% in solid, liquid and gas phase from 300 °C to 900 °C and they were 30.83%, 2.43% and 33.26% about the addition ratio of herb residue from 10 wt% to 90 wt%. When the addition of the herb residue was 0-70%, the content of chlorine in the coke increased with the increasing herb residue. When the addition of the herb residue reached 70%, it reached the maximum, which was 0.0806%. There was synergism between herb residue and coal. The content of chlorine in semi-coke (or coke) decreased with the increasing temperature at 300-900 °C. Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) were used to analyze the coke. It was found that the chlorine content in the coke obtained by the separate and mixed pyrolysis at different temperatures changed greatly.