Effects of solid additives on the control of trace elements during coal gasification
固体添加剂对煤气化过程中痕量元素的控制研究

Based on the Modified Geochemical Enrichment Factor (MGEF), the concentrations of As, Cd, Co, Cr, Cu, Mn, Hg, Pb, V, Se, Sr, Zn, twelve elements in coal and coal char were analyzed by using HG-AFS and ICP-AES. Limestone, dolomite and sodium carbonate, three kinds of solid additives were studied on the controlling law to the trace elements during coal gasification. Different additives showed different performances in the control of trace elements. The adsorbable capacity of coal char to all of trace elements was enhanced when coal was mixed with limestone and dolomite. Chemical adsorption and physical adsorption of lime, which was decomposed product of limestone under high temperature, were equally important for As, Co, Cr, Se and Zn. The effects of limestone on Cd, Cu, Hg, Pb, V and Sr were merely caused by physical adsorption of CaO. And the adsorbable capacities to Cd, Cu, V were much stronger than those to Hg, Pb, Sr. Dolomite had stronger adsorbable capacity to most of the elements (except Cu, Se, Sr) than limestone. Na_2CO_3 decreased the MGEFs of As, Cd, Cr, Pb and Se while increased the MGEFs of Zn in coal char. And Na_2CO_3 had little effect on the MGEFs of Co, Cu, Hg, V and Sr in coal char.