碱金属对汞均相氧化影响的化学动力学耦合流体动力学数值模拟

Simulation of the Effect of Alkali Metals on Homogeneous Mercury Oxidation by Chemical Kinetics Coupled with Fluid Dynamics

针对生物质中氯、碱金属含量高的特点,在生物质与煤混燃的情况下,建立Hg/C/H/O/N/S/Cl/K/Na模型,结合化学动力学计算及敏感性分析,并运用Chemkin 4.1和Fluent 6.3软件实现化学动力学与流体动力学耦合,来模拟不同Cl2体积分数下汞的均相氧化,并探讨了生物质中的碱金属对汞均相氧化的影响.结果表明:Hg的氧化活性受到温度的限制,Hg的氧化主要发生在800K左右的温度区域,此时Hg的氯化活性是最强的,但此时K的氯化活性最弱,促进了HgCl2的生成;在有碱金属存在的情况下,碱金属与Cl2的反应对Hg氧化有抑制作用,但碱金属与SO2的反应对Hg氧化有促进作用.

Considering the features of high chlorine and high alkali metal content in biomass,a Hg/C/H/O/N/S/Cl/K/Na model was established for the co-combustion process of biomass and coal.Based on kinetic calculation and sensitivity analysis,the homogeneous mercury oxidation under different concentration of Cl2 was analyzed by applying Chemkin 4.1and Fluent 6.3software to realize the coupling of chemical kinetics and fluid dynamics,so as to subsequently study the effect of alkali metals on homogeneous mercury oxidation.Results show that the Hg oxidation activity is limited by temperature.Hg oxidation mainly occurs at the temperature around 800 K,when the Hg chlorination activity is the strongest,and the K chlorination activity is the weakest,in which case the generation of HgCl2 is promoted.Additionally,in the case that alkali metal exists,the reaction between alkali metal and Cl2 would inhibit Hg oxidation,and the reaction between alkali metal and SO2 would promote Hg oxidation.