固体添加剂对煤气化过程中痕量元素的控制研究

基于改进的地球化学富集因子(MGEF)，采用氢化物发生器和原子荧光光谱法联用(HD-AFS)和电感耦合等离子发射光谱法(ICP-AES)测定了原煤和气化产生的灰焦中AS、Cd、Co、Cr、Cu、Mn、Hg、Pb、V、Se、Sr、Zn12种痕量元素含量，研究了石灰石、白云石、碳酸钠3种固体添加剂对痕量元素的控制规律，发现不同添加剂对痕量元素具有不同的抑制效果．向煤中添加石灰石和白云石后，几乎所有痕量元素在灰焦中的MGEF都增加．石灰石分解形成的CaO对AS、Co、Cr、Se、Zn的吸附既有物理吸附，也有化学吸附；对Cd、Cu、Hg、Pb、V、Sr的吸附主要是物理吸附，并且CaO对Cd、Cu、V的吸附能力大于Hg、Pb、Sr．白云石对AS、Co、Cr、Hg、Pb、V、Zn的抑制效果比石灰石好，但对Cu、Se、Sr抑制效果不及石灰石．向煤中添加碳酸钠后，灰焦中AS、Cd、Cr、Pb、Se的MGEF减少，Zn的MGEF增加，Co、Cu、Hg、V、Sr的MGEF变化不大．

Effects of solid additives on the control of trace elements during coal gasification

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.