伞罩型脱硫除尘塔NaClO_2同时脱硫脱硝实验研究
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摘要
本文介绍了我国SO2和NOx的排放状况,通过对目前我国火电厂现状的概述,说明了研发新型同时脱硫脱硝工艺的重要性,并介绍了目前国内外主要的同时脱硫脱硝方法；研究了伞罩型脱硫除尘塔(Dedusting and Desulphurization Tower with Umbrella Plates,DDTUP)的同时脱硫脱硝性能,首次把湿法同时脱硫脱硝工艺与拥有我国自主知识产权的脱硫塔型相结合；并简要的介绍了伞罩型脱硫除尘塔的设计结构、运行机理和主要优点。
利用NaClO2为吸收剂,通过模拟火电厂的工况条件,在伞罩型脱硫除尘塔内进行了同时脱硫脱硝实验研究。通过实验研究发现,NaClO2的初始浓度、吸收液的初始pH、烟气入口气速、SO2和NOx的初始浓度,液气比等对同时脱除效率有较大的影响。综合考虑经济性因素和实验分析结果,得出了伞罩型脱硫除尘塔的同时脱硫脱硝的最佳实验条件。在最佳实验条件下,伞罩型脱硫除尘塔的脱硫效率能够达到85%以上,同时脱硝效率达到67%。
在查阅了大量同时脱硫脱硝机理文献的基础上,系统地总结了SO2和NOx在NaClO2中的反应过程和吸收机理,发现NaClO2在pH 3-4之间产生的黄绿色ClO2气体具有很强的氧化能力,并且说明了NaClO2溶液脱硝原理主要源于ClO2把NO氧化成NO2,而NO2的进一步吸收通过N2O3和N2O4的水解完成。探讨了提高溶液初始pH对于减少ClO2等气体造成的二次污染的作用,首次提出了反应最佳初始pH条件应该在5左右。
在前人研究的基础上,进一步分析了SO2在NaClO2中的传质机理。分析发现,SO2在NaClO2中的吸收过程主要受气膜控制。并推导出了SO2在NaClO2中的总吸收速率公式。结果显示,SO2的吸收速率主要跟SO2的流量,入口SO2分压,以及SO2在NaClO2中的浓度有关。
The present situation of air pollution in China and simultaneous removal technologies of SO2 and NOx were consulted and reviewed in this paper. The importance of developing new technology of simultaneous removal of SO2 and NOx were showed clearly by summarizing the current status of thermal power plant in China. And the major methods of simultaneous removal of SO2 and NOx was introduced.The simultaneous desulphurization and denitrification performance in the Dedusting and Desulphurization Tower with Umbrella Plates (DDTUP) was studied in this paper.
The simultaneous desulfurization and denitrification from flue gas using desulphurization tower with self-owned intellectual property rights was reported for the frist time in China. The structural design, the operating mechanism and the chief advantages of the DDTUP were briefly introduced.Based on simulating thermal power plant conditions, experiments on removal of SO2 and NO by using NaC102 solution were carried out. The following results found that the initial concentration of NaC102, the ratio of liquid to gas, the initial gas speed,the initial pH value and the initial concentration of SO2 and NOx had important effects on the performance of the removal efficiencies. The optimal experimental conditions of the simultaneous desulfurization and denitrification using DDTUP were acertained by analyzing the experimental results and considering the economic factors. Under the optimal conditions, the simultaneous removal efficiencies of SO2 and NO by NaC102 solution reached 85% and 67%, respectively.
The mechanism of the simultaneous desulfuration and denitration using NaC102 was systematically summarized by analyzing a amount of literature about it. The yellow-green ClO2 gas which was made by NaC102 at the pH 3-4 was found having a strong oxidation. The denitrification of the NaC102 solution was showed depending crucially on ClO2 oxidation which could oxidate NO to NO2, and the further absorption of NO2 was counted as the via hydrolysis of the N2O3 and N2O4 Furthermore,reducing secondary pollution such as ClO2 by increasing the initial pH value was discussed.And the optimal initial pH value was found to be around 5 in this research for the first time.
Based on the former research, the mass transfer mechanism of SO2 in the NaClO2 solution was analyzed thoroughly. By analysis, SO2 absorption process in NaC102 was a gas controlled reaction. And the computational method of the total absorption rate of SO2 in NaC102 solution was obtained. The following results found that the total absorption rate of SO2 related to the flow rate of SO2, the inlet partial pressure of SO2 and the concentrationof SO2 in the NaC102 solution.
利用NaClO2为吸收剂,通过模拟火电厂的工况条件,在伞罩型脱硫除尘塔内进行了同时脱硫脱硝实验研究。通过实验研究发现,NaClO2的初始浓度、吸收液的初始pH、烟气入口气速、SO2和NOx的初始浓度,液气比等对同时脱除效率有较大的影响。综合考虑经济性因素和实验分析结果,得出了伞罩型脱硫除尘塔的同时脱硫脱硝的最佳实验条件。在最佳实验条件下,伞罩型脱硫除尘塔的脱硫效率能够达到85%以上,同时脱硝效率达到67%。
在查阅了大量同时脱硫脱硝机理文献的基础上,系统地总结了SO2和NOx在NaClO2中的反应过程和吸收机理,发现NaClO2在pH 3-4之间产生的黄绿色ClO2气体具有很强的氧化能力,并且说明了NaClO2溶液脱硝原理主要源于ClO2把NO氧化成NO2,而NO2的进一步吸收通过N2O3和N2O4的水解完成。探讨了提高溶液初始pH对于减少ClO2等气体造成的二次污染的作用,首次提出了反应最佳初始pH条件应该在5左右。
在前人研究的基础上,进一步分析了SO2在NaClO2中的传质机理。分析发现,SO2在NaClO2中的吸收过程主要受气膜控制。并推导出了SO2在NaClO2中的总吸收速率公式。结果显示,SO2的吸收速率主要跟SO2的流量,入口SO2分压,以及SO2在NaClO2中的浓度有关。
The present situation of air pollution in China and simultaneous removal technologies of SO2 and NOx were consulted and reviewed in this paper. The importance of developing new technology of simultaneous removal of SO2 and NOx were showed clearly by summarizing the current status of thermal power plant in China. And the major methods of simultaneous removal of SO2 and NOx was introduced.The simultaneous desulphurization and denitrification performance in the Dedusting and Desulphurization Tower with Umbrella Plates (DDTUP) was studied in this paper.
The simultaneous desulfurization and denitrification from flue gas using desulphurization tower with self-owned intellectual property rights was reported for the frist time in China. The structural design, the operating mechanism and the chief advantages of the DDTUP were briefly introduced.Based on simulating thermal power plant conditions, experiments on removal of SO2 and NO by using NaC102 solution were carried out. The following results found that the initial concentration of NaC102, the ratio of liquid to gas, the initial gas speed,the initial pH value and the initial concentration of SO2 and NOx had important effects on the performance of the removal efficiencies. The optimal experimental conditions of the simultaneous desulfurization and denitrification using DDTUP were acertained by analyzing the experimental results and considering the economic factors. Under the optimal conditions, the simultaneous removal efficiencies of SO2 and NO by NaC102 solution reached 85% and 67%, respectively.
The mechanism of the simultaneous desulfuration and denitration using NaC102 was systematically summarized by analyzing a amount of literature about it. The yellow-green ClO2 gas which was made by NaC102 at the pH 3-4 was found having a strong oxidation. The denitrification of the NaC102 solution was showed depending crucially on ClO2 oxidation which could oxidate NO to NO2, and the further absorption of NO2 was counted as the via hydrolysis of the N2O3 and N2O4 Furthermore,reducing secondary pollution such as ClO2 by increasing the initial pH value was discussed.And the optimal initial pH value was found to be around 5 in this research for the first time.
Based on the former research, the mass transfer mechanism of SO2 in the NaClO2 solution was analyzed thoroughly. By analysis, SO2 absorption process in NaC102 was a gas controlled reaction. And the computational method of the total absorption rate of SO2 in NaC102 solution was obtained. The following results found that the total absorption rate of SO2 related to the flow rate of SO2, the inlet partial pressure of SO2 and the concentrationof SO2 in the NaC102 solution.
引文
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[2]付融冰,张慧明.中国能源的现状[J].能源环境保护,2005,9(1)：38-42
[3]叶荣泗.今日中国电力工业[M].北京：外文出版社,2004：34-35
[4]国家发改委.国家发展和改革委员会煤炭工业“十一五”发展规划[R],2007：5-6
[5]国家统计总局.中华人民共和国2006年国民经济和社会发展统计公报[R].2006：18
[6]姜艳萍、王国清.中国环境污染状况和对策[M].北京：中国环境科学出版社,1993：17-36
[7]朱法华.火电建设面临的环保形势与任务分析[J].环境科学研究,2005,18(4)： 21-29
[8]肖荣欣,李钟伟,程烨环.浅谈煤中硫对环境的影响[J].环境研究与监测,2006,19(4)：55-56
[9]国家环保总局.两控区酸雨和二氧化硫污染防治“十五”计划[R].2004：6-10
[10]王书肖、陆永琪.燃煤二氧化硫污染控制技术手册[M].北京：化学工业出版社,1996：99-147
[11]谢国勇,刘振宇,刘有智.用CuO/γ-A12O3催化剂同时脱除烟气中的SO2和NO[J].催化学报.2004,25(1)：33-38
[12]Onda K. Electric discharge removal of SO2 and NOx from combustion flue gas bypulsed corona discharge[J]. Energy Conversion and Management,1997, 38(10):1377-1378
[13]陆诗建,杨向平,杨帅.烟道气脱硫脱硝一体化技术进展[J].油气田环境保护,2009,19(3)：1-4
[14]Kaczur, Jerry J. Oxidation chemistry of chloric acid in NOX/SOX and air toxic metal removal from gas streams[J]. Environmental Progress,1996,15(4): 245-354
[15]Adewuyi, Yusuf G., He Xiangdong. Simultaneous absorption and oxidation of NO and SO2 by aqueous solutions of sodium chlorite[J]. Chemical Engineering Communications,1999,174:21-51
[16]彭会清,胡海祥,赵根成,等.烟气中硫氧化物和氮氧化物控制技术综述[J].广西电力,2003,(4)：64-68
[17]J.A.Rodriguez, M.Perez, T.Jirsak, et al. DeNO_x Reactions on MgO(100), Zn_xMg-(1-x)O(100), Cr_xMg_(1-x)O(100), and Cr2O_3(0001):Correlation between Electronic and Chemical Propertiesof Mixed-Metal Oxides[J]. The journal of physical chemistry,2001,105(23):56-67
[18]李燕.电子束烟气脱硫脱硝技术[J].西山科技,2002,6(增刊)：3-5
[19]汤宗慧,徐光.电子束半干法烟气净化技术[J].华东电力,2003,8：9-10
[20]Kawamura K., J. Atom Energy Socz[M]. Japan,1972:54-56
[21]Kawamura K.. Radiat. PhysChem[M]. Japan,1979:179-180
[22]Robert.J.G., Dennis.J.H., The development and application of biosensing devices for bioreactor monitoring and control[J]. Chemical Engineering Progress,1985,81(10):213-320
[23]魏培平,董丽敏,杨嘉祥.脉冲电晕等离子体脱硫、脱氮研究[J].哈尔滨师范大学学报,2001,17(6)：68-72
[24]Onda K. Electric discharge removal of SO2 and NOx from combustion flue gas by pulsed corona discharge[J]. Energy Conversion and Management,1997, 38(10-13):1377-1378
[25]Chang S.G. Kinetics of Reaction in a wet Flue Gas Simutaneous Desulfurization and Denirification System In Flue Gas Desulfurtration[J]. ACS Symp,1982,182:1211-1255
[26]姚玉英,陈常贵,柴诚敬.化工原理(下册)[M].天津大学出版社,2002：100-102
[27]刘凤,赵毅,王亚君,等.酸性NaC102溶液同时脱硫、脱硝的实验研究[J].动力工程,2008,28(3)：425-429
[28]王琼,胡将军,邹鹏.NaC102湿法烟气脱硫脱硝技术的研究[J].江西电力,2004,28(6)：14-16
[29]黄云翔.氯酸钠,亚氯酸钠和ClO2的制造与应用[J].广州化工,1997,25(3)： 15-20
[30]黄云翔.国内外亚氯酸钠生产应用概况[J].氯碱工业,1994,12：28-30
[31]柴玉星.NaClO2漂白工艺的优化[J].山东纺织科技,1999,5：42-43
[32]杜方尧,陈曙明.针织物亚氯酸钠漂白工艺的改进[J].针织工业,2004,4(2)： 61-62
[33]诸爱士,蒋家新,苏晓霞.亚氯酸钠制备ClO2及其杀菌效果研究[J].食品工业科技,2006,1：174-177
[34]贺启环,谢惠芳.稳定性ClO2溶液中ClO2存在形态的研究[J].工业水处理,2001,21(4)：8-10
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