CO在H_2/Cl_2/O_2/N_2混合气体中氧化的动力学模拟

Kinetic modeling of CO oxidation in H_2/Cl_2/O_2/N_2 mixture

利用详细的化学反应动力学模型研究了CO在H2/Cl2/O2/N2混合气体中的氧化反应,考查了混合气体中氯和氢的量之比、反应温度、停留时间和氧浓度等参数对CO氧化的影响,并用敏感性分性方法研究了不同条件下氯对CO氧化的抑制机理.结果表明,减小混合气体中氯和氢的量之比或提高反应温度是促进CO氧化的主要方法.在800℃以下氯对CO氧化的抑制作用主要表现为Cl+HO2=HCl+O2,进而减少了通过H+HO2=OH+OH生成的OH.在900℃以上,氯的抑制作用主要通过反应HCl+OH=H2O+Cl减小OH的浓度,同时Cl+CO=ClCO等的反应也减缓了CO2的生成速率;通过反应HCl+O=OH+Cl,减轻了氯对CO氧化的抑制作用.

A detailed kinetic model for CO oxidation in H2/Cl2/O2/N2 mixture was developed to investigate the dependance of CO conversion on various parameters such as chlorine to hydrogen mole ratio,reaction temperature,residence time and excess air. The inhibition mechanism of chlorine at different conditions was also discussed with sensitivity analysis. The results show that the most effective method to promote CO oxidation is to decreasing the mole ratio of chlorine to hydrogen or increasing the reaction temperature. At a temperature under 800 ℃,chlorine inhibits the cooxidation process mostly through Cl＋HO2 HCl＋O2,which decreases the OH formation through H＋HO2 OH＋OH. When the temperature exceeds 900 ℃,chlorine inhibits the cooxidation process through HCl＋OH H2O＋Cl,which decreases the OH concentration,while the reaction Cl＋CO ClCO decreases the CO2 formation rate as well. The inhibition effect is partly overcome through the reaction HCl＋O OH＋Cl.