尿素/飞灰混合浆液同时脱硫脱氮反应热力学分析  

Thermodynamic analysis on the reaction to the desulfurization and denitrification via the urea/fly ash mix-solution

作　　者：史晓君[1] 李瑛[1] 

机构地区：[1]昆明理工大学冶金与能源工程学院,昆明650093

出　　处：《安全与环境学报》2014年第4期196-202,共7页Journal of Safety and Environment

摘　　要：为实现烟气同时脱硫脱氮,从热力学角度对尿素/飞灰混合浆液同时脱硫脱氮的机理进行了分析;通过XRF测定了飞灰中主要成分的质量分数,并用XRD表征判断尿素和飞灰混合前后的主要成分是否改变;根据测试分析结果和气液反应规律,计算各反应达到平衡时SO2和NOx的分压及反应的吉布斯自由能变,从反应机理方面说明飞灰中主要成分对混合浆液同时脱硫脱氮反应的影响,并确定了相关反应的可行性及适宜温度区间。结果表明,飞灰添加到尿素中对脱硫反应有促进作用,对脱氮反应没有抑制作用,从各反应吉布斯自由能判断,反应是可行的,因此,尿素/飞灰混合浆液同时脱硫脱氮是可行的,且适宜的反应温度为298~380 K。This paper is engaged in a thermodynamic analysis of the reaction to the simultaneous desulfurization and denitrification via the urea/fly ash mixsolution as well as an investigation of the corre sponding reaction mechanism. As is known, the above said reactions tend to take place in the mixed solution of urea/fly ash. In our inves tigation, we have adopted XRF to detect the contents of main compo nents in the fly ash. At the same time, we have also used the XRD pattern to determine the main chemical compositions in the fly ash and the mixture of the mixed solution with the urea. The reason for us to do so is that the detected results can help to identify the main chemical compositions participating in the reactions and the changes that take place in the related transformation during the thermodynamic process. And, in turn, the detected results can be taken as a ground foundation for establishing the related formulae of the desulfurization and denitrification. In our investigation, we have also worked out the partial pressure of SO2 and NOx based on the detected results and the reaction regularity between the gas and liquid. In addition, we have also found the equilibrium between the different partial pressure of SO2 and NOx and the related reactions of the said compositions. It says that with the increase of the temperature, it is possible for the different partial pressures of SO2 and NO~ in the reactions to reach e quilibrium when the corresponding reactions arrive at their own re spective equilibrium state. In addition, the variation value of Gibbs free energy in different equilibriums at different temperatures can alsobe worked out. Moreover, considering the partial pressure in different reactions and the mechanism of reactions, it would be possible to de termine the impact caused by the main components in the fly ash on flue gas desuffurization or denitrification. Furthermore, considering the variation value of Gibbs free energy and the thermodynamic prin ciples, it will also be possible to determine the fe

关 键 词：环境工程学 烟气脱硫脱氮 尿素 飞灰 分压 吉布斯自由能 

分 类 号：X773[环境科学与工程—环境工程]