电位分析法用于湿法脱硫浆液氧化控制的理论研究  

Theoretical study on potentiometric analysis applied to oxidation control of wet desulfurization slurry

作　　者：房孝维 何育东[1] 宦宣州 李兴华[1] 陶明[1] 王泽[2] FANG Xiaowei;HE Yudong;HUAN Xuanzhou;LI Xinghua;TAO Ming;WANG Ze(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China;State Key Laboratory of Multi-Phase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]西安热工研究院有限公司,陕西西安710054 [2]中国科学院过程工程研究所,北京100190

出　　处：《热力发电》2023年第8期81-86,共6页Thermal Power Generation

基　　金：中国华能集团有限公司总部科技项目(HNKJ21-HF182)。

摘　　要：氧化还原电位(ORP)分析法已逐渐应用于石灰石-石膏湿法脱硫浆液氧化控制领域,但目前缺乏相应的理论研究。首先基于密度泛函理论及酸解离平衡计算得到了浆液氧化过程中各电对标准电极电位E^(θ)(O_(2)(aq))/H_(2)O及E^(θ)(S(Ⅵ)/S(Ⅳ)),并获得了各反应的标准电动势;然后,以浆液氧化主反应2HSO_(3)^(-)+O_(2)→2H++2SO_(4)^(2-)为基础,基于Nernst方程建立反应体系电动势理论计算模型,并通过实验研究发现,反应体系电动势实测值ORP与理论计算值EMF相差较大,表明Nernst方程不适用于浆液氧化体系;最后,通过逐步回归法建立了实测ORP与pH值、ln(c(Ca^(2+)))、ln(c(HSO_(3)^(-)))及ln(c(O_(2)))之间良好的多元线性拟合关系,该结果表明浆液氧化进程不仅与ORP有关,同时受pH值、钙离子及溶解氧浓度控制,因此以ORP为湿法脱硫浆液氧化控制指标时,应同时兼顾pH值、钙离子及溶解氧浓度的影响。Oxidation reduction potential(ORP)analysis method has been gradually used in the field of limestone-gypsum wet desulfurization slurry oxidation control,but there is a lack of corresponding theoretical research.In this paper,firstly,the standard electrode potentials of each pair in the slurry oxidation process,E^(θ)(O_(2)(αq))/H_(2)O and E^(θ)(S(Ⅵ)/S(Ⅳ)),were obtained based on density functional theory and acid dissociation equilibrium calculation;and the standard electromotive force of each reaction was calculated.Then,based on the main reaction of slurry oxidation,2HSO_(3)^(-)+O_(2)→2H++2SO_(4)^(2-),the theoretical calculation model of the electromotive force of the reaction system was established by the Nernst equation.It was found that the measured ORP of the electromotive force of the reaction system was quite different from that by theoretical calculation,which meant the Nernst equation was not suitable for the slurry oxidation system.Finally,a good multivariate linear fitting relationship between the measured ORP,pH,ln(c(Ca^(2+))),ln(c(HSO_(3)^(-)))and ln(c(O_(2)))was established by the stepwise regression.The results indicated that the process of slurry oxidation was not only related to the single indicator of ORP,but also controlled by pH,calcium ion and dissolved oxygen concentration.When ORP is used as the oxidation control indicator of wet desulfurization slurry,the influence of pH,calcium ion and dissolved oxygen concentration should be taken into account at the same time.

关 键 词：湿法脱硫 浆液氧化控制 电位分析法:Nernst方程 逐步回归 

分 类 号：X773[环境科学与工程—环境工程]