The characteristic of biomass gas tar removal by a quench coupled with adsorption process

The effective removal of tar is one of the main obstacles to the large-scale industrialization of biomass gasification process. A quench coupled with multiple adsorption technology (QCADT) for the tar stagewise removal was developed and patented. Based on an experimental device of QCADT, the tar removal behavior as well as the removal mechanism was measured and analyzed respectively. The results show that, the tar has been removed cascadedly in accordance with the idea of QCADT, providing a residual tar concentration of less than 10 mg/Nm³. However, the measured results represent boundary differences to the tar classification in QCADT baesd on IUPAC (International Union of Pure and Applied Chemistry) pore size classification, leading to the residual heavier tar moving to the downstream stage and forming a competitive adsorption. Mesoporous and microporous units can hardly lower the dew point of the heavy tar. Mesopores play dominant role in the medium tar removal, which is the most difficult to be removed. The results of the tar dew point prove the effectiveness of the QCADT based on the correspondence of the tar classification, the tar molecular size and the pore size of the adsorbent.