摘要
基于湿法脱硫中试台,开展湿法脱硫塔内含灰浆液对系统过程化学影响。试验表明:石膏、飞灰的当量脱硫能力仅相当于新鲜脱硫剂的0.4、1%。吸收塔内浆液飞灰浓度为0%、1.5%、3.0%、6.0%时,飞灰对系统脱硫效率均具有一定的促进作用,且pH值越低,效应越明显。与空白工况相比,pH值为5.6~6.0,效率增幅分别为0.37%、0.55%、0.75%;pH值为5.0~5.5,对应增幅为0.75%、0.91%、1.23%。系统脱硫时间有随着浆液中飞灰含量增加而逐渐缩短的趋势,pH值降至5.4时,系统脱硫持续时间分别为156、148、130、100 min。低pH值下飞灰溶解浸出大量的Fe~(3+)、Mn~(2+),石膏浆液催化氧化性能加强,SO_3~(2-)浓度显著越低。总体而言,浆液中SO_3~(2-)含量与浆液pH值呈正向相关,而与浆液中飞灰含量负向相关。
Based on the pilot plant of limestone-gypsum wet flue gas desulfurization,the efficiency of desulfurization,acidification and desulfurization reaction,consumption of limestone,CaCO_3in gypsum and oxidation of SO_3~(2-)with different mass concentration of fly ash in slurry were studied.Results showed that the equivalent desulfurization capacity of gypsum and fly ash is only 0.4%and 1%of that of fresh desulfurizer.When the fly ash concentration is 0%,1.5%,3.0%and 6.0%,the fly ash in slurry can promote the efficiency of desulfurization.Compared with the blank condition,the efficiency increases are 0.75%,0.91%,and 1.23%with the pH value of 5.6~6.0 and 0.37%,0.55%and 0.75%while the pH value is 5.0~5.5,respectively.After adding fly ash,the desulfurization reaction time of the slurry was shortened with different p H values.The higher the pH value,the more obvious the effect.SO_3~(2-)content in gypsum slurry is positively correlated with pH value,but negatively correlated with fly ash content in slurry.The lower the pH value,the higher the precipitation of Mn~(2+),Fe~(3+),the stronger the catalytic oxidation ability,and the lower the concentration of SO_3~(2-)in the slurry.
引文
[1]李东梅,董雪峰,郭阳,等.电厂湿法脱硫系统石膏脱水困难的影响因素[J].热力发电,2011,40(10):4-8.Li Dongmei,Dong Xuefeng,Guo Yang,et al.Analysis of affecting factors on difficult dehydration of gypsum used for wet desulphurization in power plants[J].Thermal Power2011,40(10):4-8.
[2]杜晓光,马筠,吴颖庆,等.火电厂燃煤及固体产物中危害元素的测定方法、迁移规律及对环境影响研究[J].热力发电2015,39(11):16-22.Du Xiaoguang,Ma Yun,Wu Yingqing,et al.Study on determination method of hazardous elements in fuel coal and other solid by-products in thermal power plants,their migration rules during combustion,and their influence upon environment[J].Thermal Power,2015,39(11):16-22.
[3]梁磊.火电厂脱硫系统石膏脱水困难案例分析及对策[J]中国电力,2013,46(1):99-102.Liang Lei.Case analysis and solutions of gypsum dewatering for FGD systems of power plants[J].Electric Power2013,46(1):99-102.
[4]黄昶,黄汝玲,郑仙荣,等.钙基水合改性飞灰吸附剂脱除模拟烟气中SO2的实验研究[J].科学技术与工程,2017,17(23):108-114.Huang Chang,Huang Ruling,Zheng Xianrong,et al.The study on the adsorption performance of SO2with activated fly ash from the simulated flue gas[J].Science Technology and Engineering,2017,17(23):108-114.
[5]林军,王凡,张凡,等.蒸汽活化石灰-飞灰的烟气脱硫实验研究[J].应用基础与工程科学学报,2006,14(2):174-180.Lin Jun,Wang Fan,Zhang Fan,et al.Experimental study of semi-dry FGD by means of fly ash activation[J].Journal of Basic Science and Engineering,2006,14(2):174-180.
[6]钱枫,裘晓鹏,李晓岩.飞灰/石灰吸着剂制备及其脱硫脱硝性能的研究[J].环境科学与技术,2009,32(2):56-59.Qian Feng,Qiu Xiaopeng,Li Xiaoyan.Performance of fly ash/lime sorbents for simultaneous removing SO2and NOx from flue gas[J].Environmental Science&Technology,2009,32(2):56-59.
[7]吴忠标,余世清.飞灰和废大理石烟气脱硫的传质-反应研究[J].环境科学学报,2002,22(6):768-772.Wu Zhongbiao,Yu Shiqing.Mass transfer-reaction study on flue gas desulfurization with fly ash and waste marble[J].Acta Scientiae Circumstantiae,2002,22(6):768-772.
[8]余世清,吴忠标.飞灰及其混合脱硫剂浆液脱硫特性的实验研究[J].环境污染与防治,2002,24(6):335-338.Yu Shiqing,Wu Zhongbiao.Study on desulfurization performance of fly ash and its mixture absorbent slurry[J].Environmental Pollution and Control,2002,24(6):335-338.
[9]赵永椿,张军营,张富强,等.燃煤高钙灰的组成及其演化机制的研究[J].中国电机工程学报,2007,27(29):12-16.Zhao Yongchun,Zhang Junying,Zhang Fuqiang,et al.Evolution Mechanism and Chemical Composition of High Calcium Fly Ashes From Coal Combustion[J].Proceedings of the CSEE,2007,27(29):12-16.
[10]张盈文,金晶,刘娓,等.湿法脱硫系统中飞灰对SO2氧化特性的影响[J].煤炭转化,2015,38(2):75-78.Zhang Yingwen,Jin Jing,Liu Wei,et al.Effect of fly ash on oxidation of SO2in a wet flue-gas desulfurization system[J].Coal Conversion,2015,38(2):75-78.
[11]张东平,李乾军,刘献锋,等.湿法烟气脱硫石膏-飞灰浆液的浸出与传质特性[J].动力工程学报,2011,31(10):761-767.Zhang Dongping,Li Qianjun,Liu Xianfeng,et al.Mass transfer and leaching behavior of gypsum-fly ash slurry for wet flue gas desulphurization[J].Journal of Chinese Society of Power Engineering,2011,31(10):761-767.
[12]李春雨,董越,齐勇,等.石灰石-石膏湿法脱硫系统结垢及飞灰影响特性研究[J].环境工程,2014,32:513-517.Li Chunyu,Dong Yue,Qi Yong,et al.The investigation of scaling characteristics of limestone-gypsum wet flue gas desulfurization and the influence of fly ash on scaling[J].Environmental Engineering,2014,32:513-517.
[13]蒋路漫,周振,俞杰,等.烟气脱硫中亚硫酸钙铁锰复合催化氧化优化[J].环境工程学报,2017,12(11):6332-6338.Jiang Luman,Zhou Zhen,Yu Jie,et al.Optimization for FeMn catalyzed sulfite oxidation in flue gas desulfurization[J].Chinese Journal of Environmental Engineering,2017,12(11):6332-6338.
[14]马双忱,杨静,张立男,等.湿法脱硫浆液的氧化控制缺陷及对策[J].化工进展,2016,35(8):2547-2552.Ma Shuangchen,Yang Jing,Zhang Linan,et al.Defects and countermeasures of slurry oxidation control in the Wet-FGD[J].Chemical industry and engineering progress,2016,35(8):2547-2552.
[15]陈洪涛,施依娜,陆俊超,等.石灰石-膏湿法烟气脱硫系统中锰元素的行为方式研究[J].华东电力,2010,38(10):1611-1614.Chen Hongtao,Shi Yina,Lu Junchao,et al.Study on manganese element behavior in limestone-gypsum wet flue gas desulfurization system[J].East China Electric Power,2010,38(10):1611-1614.