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针对生物质中Cl和碱金属含量高的特点,研究生物质与煤混燃过程中Hg的氧化机制。使用化学热力学软件Chemical Equilibrium with Applications(CEA)建立C/H/O/N/S/Cl/K/Na模型,分析碱金属元素K、Na与非金属元素Cl和S的反应,发现1100K以下Cl仍然主要以HCl形式存在,SO2的含量逐渐减少,碱金属主要以碱金属硫酸盐(A2SO4)的形式存在,这对Hg的氧化反应变得更为有利,同时随着生物质的添加,这种趋势更为明显。同时使用动力学软件Chemkin4.1构建了Hg/C/H/O/N/S/Cl/K/Na的化学和气相平衡模型,进一步研究了生物质与煤混燃过程中对Hg氧化的影响。计算结果表明,生物质与煤之比越高,对Hg的氧化越有利,生物质中高含量的Cl是促进Hg氧化最主要的因素,而K、Na的存在对Hg的氧化有进一步的促进作用,这进一步证实了热力学计算结果。
In view of the high content of Cl and alkali metals in biomass, the oxidative mechanism of Hg during biomass co-combustion with coal was studied. The C / H / O / N / S / Cl / K / Na model was established by Chemical Equilibrium with Applications (CEA) software to analyze the reaction of alkali metal elements K and Na with nonmetal elements Cl and S. Still exists mainly in the form of HCl, the content of SO2 is gradually reduced, and the alkali metal is mainly in the form of alkali sulfate (A2SO4), which makes the oxidation reaction of Hg more favorable. At the same time, with the addition of biomass, The trend is even more obvious. At the same time, the chemical and gas phase equilibrium models of Hg / C / H / O / N / S / Cl / K / Na were constructed using the kinetic software Chemkin4.1 to further study the effect of Hg oxidation during the co- . The results show that the higher the ratio of biomass to coal, the more favorable the oxidation of Hg, the higher content of Cl in biomass is the most important factor to promote Hg oxidation, while the presence of K and Na further promote the oxidation of Hg , Which further confirmed the thermodynamic calculation results.