Simulated biomass tar removal mechanism and performance by a Quench Coupled with ABsorption Technology

Tar removal is one of the major limitations to the large-scale industrialization of biomass gasification technology. Quench Coupled with ABsorption Technology (QCABT) has been developed and patented to alleviate this obstacle. Cyclohexane and n-dodecane were used as the simulated light and heavy tars, respectively, and their removal performance and the mechanism of their removal by QCABT were evaluated. The results show that modified diesel is the preferred cyclohexane absorbent because of the resulting high removal rate. The concentration of n-dodecane can be reduced to about 15% in the quench scrubber, and is decreased to less than 1% in the absorber. QCABT exhibits both cooling and absorption effects in the quench scrubber upon the removal of cyclohexane, providing a total removal efficiency of 98%. The quenching temperature plays a dominant role in n-dodecane removal, and exhibits a beneficial linear relationship based on the Antoine equation. The mass ratio of the absorbent to the coolant couples the activities of the quench scrubber and the absorber. Varying tar sampling concentrations change the tar loading distributions in the quench scrubber and the absorber. The modified diesel can be regenerated effectively after being purged for 125 min at 50 °C.