Effects of oil shale on PM10 formation during Zhundong coal gasification under entrained flow gasification conditions

Zhundong coal usually causes severe fine particulate (PM10) emissions and ash deposition problems during its utilization, and additives rich in silicon and aluminum can effectively mitigate these problems. Oil shale has high contents of silicon and aluminum, which can be used to lower the formation of PM10 during Zhundong coal gasification. In this study, the effect of oil shale on PM10 formation during Zhundong coal gasification was investigated in a flat-flame burner. The results showed that the particle size distributions of PM10 were bimodal with the addition of oil shale. The yields of PM10 and Na release rates were lowered with increasing addition ratio of oil shale. Besides, the presence of organic matter in oil shale inhibited the Na release and weakened the collision and coagulation between Na and other particles. Oil shale reduces Na release via four pathways: (I) Si, Al-based minerals react with Na vapor to generate aluminosilicates; (II) Organic matter released from oil shale blocks coal pores and prevents the release of Na; (III) The pore-rich shale coke formed from oil shale pyrolysis has strong adsorption effect on Na; and (IV) Na was embedded in the lattice of organic macromolecules and retained in the organic products. These results confirmed the feasibility of oil shale on the PM10 reduction in the Zhundong coal gasification.