随着褐煤作为动力用煤重要性的提高以及人们对重金属污染的重视，富含含氧官能团的褐煤使Cr向有机态富集导致燃烧过程中Cr的转化行为发生重大改变，特别是O2/CO2燃烧反应气氛改变及炉内喷钙技术的使用，造成大量剧毒Cr(VI)排放的危险，因此研究褐煤O2/CO2燃烧Cr的迁移及氧化路径成为控制Cr(VI)的关键问题。但是高浓度HCl/SO2/H2O和Ca/Mg/Na/K/Fe矿物同时存在的复杂反应体系中Cr的均相非均相反应机理，及对生成Cr(VI)的促进和抑制作用的耦合过程还缺乏深入认识。本项目针对上述问题，研究我国褐煤中Cr的赋存分布及燃烧过程中的反应动力学机理。通过实验与模拟相结合的方法，揭示Cr的氧化路径并获得不同因素与Cr反应的动力学数据，建立模型模拟复杂反应体系下Cr(VI)生成的促进与抑制作用的耦合过程，提出Cr(VI)生成控制思路，为有效控制褐煤燃烧Cr(VI)的排放奠定理论基础。

Organic-Cr is the main Cr species in lignite due to its high content of oxygen-containing functional groups. The behavior of organic Cr is quite different with that of inorganic Cr in the high-rank coals, especially under oxy-fuel combustion, the change of combustion atmosphere and the utilization of limestone furnace-injection technique cause a large number of toxic Cr(VI) emission. The oxidation and transformation mechanism of Cr during lignite oxy-fuel combustion is a critical component for Cr(VI) control. However, the homogeneous and heterogeneous reaction mechanisms of Cr in the system of high concentrations of HCl/SO2/H2O together with Ca/Mg/Na/K/Fe coal-minerals are still unclear. Moreover, no relevant investigation has revealed the effect of competitive reactions on promotion and inhibition of Cr(VI) formation during lignite combustion. This proposed project is to investigate the content distributions/species of Cr in Chinese lignites and the kinetics/model of Cr transformation during combustion upon experiments and simulation calculations. Based on the studies of Cr oxidation mechanisms and the kinetics data of Cr reacted with different compounds, a model is developed to simulate and reveal the promotion and inhibition effects on Cr(VI) formation during lignite combustion. Finally, the control methods of Cr(VI) are proposed, which will lay a theoretical foundation for effective control of Cr(VI) during lignite combustion.