Partitioning of arsenic in slurry feed entrained-flow gasifier with wet gas cooling cleaning system

Slurry feed entrained-flow gasifier has been applied more and more in waste treatment. However, the data on the distribution and emission of arsenic (As) in such gasifiers are very limited. The fate of As in gasification system is closely related to the conditions of gasifier and subsequent gas treatment processes. In this paper, the partitioning of As in slurry feed entrained-flow gasifier with wet gas cooling cleaning system is determined. The influence of feedstock and process water are studied. It is shown that co-gasification waste with coal and the redox condition of process water have little effect on the overall distribution of As. 91.7–94.5% of As is distributed to flash wastewater under water-oxidizing condition and 85.5–99.7% of As partitions into the wastewater under water-reducing condition. Less than 4% of As enters the raw syngas. Under the condition of waste addition and reducing water, As has the risk of being released into the atmosphere with the exhaust gas (8.4–57.0 μg/Nm3). According to the data detected under water-oxidizing condition, the concentration of As in clarified water is 0.367–1.195 ppm, and that in clarifier solid is 34.06–159.84 ppm. Therefore, the reuse of clarified water as process water of wet gas treatment system and clarifier solid as feedstock of gasifier may lead to As recycling in the gasification system.