Emission Characteristics of Organic Pollutants during Coprocessing of Coal Liquefaction Residue in Texaco Coal–Water Slurry Gasifier

Field tests were conducted to research the emission characteristics and environmental risk of organic pollutants during coprocessing of coal liquefaction residue (CLR) in Texaco coal–water slurry gasifier. Changes of temperature, pressure, and syngas composition in the gasifier were recorded under blank condition (without mixing CLR in the slurry) and test condition (15% CLRs were mixed into the slurry). Also the toxicity equivalent concentration of 16 kinds of polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-<i>p</i>-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) and the concentration of volatile organic compounds (VOCs) in all the solid waste, liquid, and gas emissions under two conditions were analyzed. Results showed that, during the coprocessing process, the pressure and syngas production of the gasifier were essentially unaffected and the temperature in the gasifier increased 5–11 °C and promoted the formation of H₂ and CO. The concentration of PAHs in part of the gas emission, liquid emission, and solid waste increased 1.0–1.3 μg/m³, 19 ng/L, and 1.4–2.3 mg/kg, respectively, during the coprocessing process, but the total toxicity equivalent concentrations were still far lower than relevant standard limits; the emission of PAHs during coprocessing of CLR in Texaco coal–water slurry gasifier has low environmental risk. The concentration of PCDD/Fs in liquid emission and solid waste decreased 0.002 ng of total equivalent quantity (TEQ)/L and increased 0.0002 μg of TEQ/kg, respectively; the environmental risk was rather low. The concentrations of VOCs in gas samples were far below the blank condition under test condition and were mostly not detected or below the detection limits in the liquid emission and solid waste, and VOCs emission in the coprocessing process has low environmental risk