基于TiO_2表面紫外光催化降解高浓度SF_6的实验与仿真研究
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摘要
SF_6具有较高的温室效应潜在值(global warming potential, GWP),未经处理排放到大气中会对环境产生影响。电力工业中SF_6的应用越来越广泛,废气排放量也高速增长。为减少电力工业中SF_6废气对环境的污染,基于TiO_2表面在紫外光照射下具有催化效应这一特性,设计了一套实验平台,研究了不同数量的Ti O_2催化剂和有H_2O参与时对常温常压下高浓度SF_6降解效果的影响,并通过仿真分析了SF_6气体分子在TiO_2表面的断键分解过程。研究结果表明:TiO_2作为催化剂能够有效提高SF_6的降解率。其中,未加TiO_2时SF_6在紫外光照3 h后的降解率仅为1.25%,加入8个TiO_2片时相同条件下3h降解率达到8.98%,降解产物主要有SO_2F_2、SiF_4、SF4以及SO_2;在此基础上,在SF_6气体中混入H_2O能把降解率提高到27.22%,降解产物主要有SO_2F_2、SiF_4、SF4、Si H_4、HF和SO_2。仿真计算结果表明TiO_2催化降解SF_6过程是把所需的能量细分为几个小的能量吸收过程,从能量吸收的角度解释了TiO_2催化降解SF_6的优势。研究结果可为SF_6的降解提供参考。
SF_6 has a high global warming potential(GWP), and will be harmful to the environment if the SF_6 is discharged into the atmosphere without treatment. The SF_6 is more extensively applied in the power industry and the exhaust emissions are also increasing rapidly. In order to reduce the environmental pollution of SF_6 exhaust gas in power industry, we designed a set of experimental platform based on the catalytic effect of TiO_2 surface under ultraviolet irradiation to study the effects of different amounts of TiO_2 and H_2 O participation on the degradation of high concentrations of SF_6 at normal temperature and pressure. At the same time, the process of catalytic decomposition of SF_6 gas molecule on TiO_2 surface was analyzed by simulation. The results show that TiO_2, as a catalyst, can effectively increase the degradation rate of SF_6.The degradation rate of SF_6 after ultraviolet irradiation for 3 hours in the absence of TiO_2 was only 1.25% and the degradation rate reached 8.98% with 8 pieces of TiO_2 added, and the main degradation products were SO_2 F_2, SiF_4, SF_4,and SO_2. Besides, H_2 O addition in SF_6 gas can increase the degradation rate to 27.22%. The main degradation products are SO_2 F_2, SiF_4, SF_4, SiH_4, HF, and SO_2. The simulation calculation results show that the TiO_2 catalytic degradation of SF_6 is to subdivide the required energy into several small energy absorption processes which explains the advantages of TiO_2 catalytic degradation of SF_6 from the perspective of energy absorption. The study can provide a reference for the degradation of SF_6.
SF_6 has a high global warming potential(GWP), and will be harmful to the environment if the SF_6 is discharged into the atmosphere without treatment. The SF_6 is more extensively applied in the power industry and the exhaust emissions are also increasing rapidly. In order to reduce the environmental pollution of SF_6 exhaust gas in power industry, we designed a set of experimental platform based on the catalytic effect of TiO_2 surface under ultraviolet irradiation to study the effects of different amounts of TiO_2 and H_2 O participation on the degradation of high concentrations of SF_6 at normal temperature and pressure. At the same time, the process of catalytic decomposition of SF_6 gas molecule on TiO_2 surface was analyzed by simulation. The results show that TiO_2, as a catalyst, can effectively increase the degradation rate of SF_6.The degradation rate of SF_6 after ultraviolet irradiation for 3 hours in the absence of TiO_2 was only 1.25% and the degradation rate reached 8.98% with 8 pieces of TiO_2 added, and the main degradation products were SO_2 F_2, SiF_4, SF_4,and SO_2. Besides, H_2 O addition in SF_6 gas can increase the degradation rate to 27.22%. The main degradation products are SO_2 F_2, SiF_4, SF_4, SiH_4, HF, and SO_2. The simulation calculation results show that the TiO_2 catalytic degradation of SF_6 is to subdivide the required energy into several small energy absorption processes which explains the advantages of TiO_2 catalytic degradation of SF_6 from the perspective of energy absorption. The study can provide a reference for the degradation of SF_6.
引文
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[19]KUDO A,MISEKI Y.Heterogeneous photocatalyst materials for water splitting[J].Chemical Society Reviews,2009,38(1):253-278.
[20]MAEDA K.Photocatalytic water splitting using semiconductor particles:history and recent developments[J].Journal of Photochemistry&Photobiology C Photochemistry Reviews,2011,12(4):237-268.
[21]CHEN X,MAO S S.Titanium dioxide nanomaterials:synthesis,properties,modifications,and applications[J].Chemical Reviews,2007,107(7):2891-2959.
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[23]ZHANG J,ZHANG Y,LEI Y,et al.Photocatalytic and degradation mechanisms of anatase TiO2:a HRTEM study[J].Catalysis Science&Technology,2011,1(2):273-278.
[24]KIM J H,CHO C H,SHIN D H,et al.Abatement of fluorinated compounds using a 2.45 GHz microwave plasma torch with a reverse vortex plasma reactor[J].Journal of Hazardous Materials,2015,294:41-46.
[25]杨宇玲,郭新良,崔兆仑,等.紫外吸收光谱法检测SF6分解产物中的H2S[J].高电压技术,2018,44(8):2573-2579.YANG Yuling,GUO Xinliang,CUI Zhaolun,et al.Determination of H2S in SF6 decomposition products by ultraviolet absorption spectrometry[J].High Voltage Engineering,2018,44(8):2573-2579.
[26]DELLEY B.An all-electron numerical method for solving the local density functional for polyatomic molecules[J].Journal of Chemical Physics,1990,92(1):508-517.
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[28]DELLEY B.Hardness conserving semilocal pseudopotentials[J].Physical Review B,2002,66(15):155125.
[29]YANG Y,EVANS J,RODRIGUEZ J A,et al.Fundamental studies of methanol synthesis from CO2 hydrogenation on Cu(111),Cu clusters,and Cu/ZnO(0001[combining macron])[J].Physical Chemistry Chemical Physics,2010,12(33):9909-9917.
[30]ZUO Z J,LI N,LIU S Z,et al.Initial stages of oxidation for Cu-based catalysts using density functional theory[J].Applied Surface Science,2016,366:85-94.
[31]RAMOS M,DíAZ C,MARTíNEZ A E,et al.Dissociative and non-dissociative adsorption of O2 on Cu(111)and Cu ML/Ru(0001)surfaces:adiabaticity takes over[J].Physical Chemistry Chemical Physics,2017,19(16):10217-10221.
[32]YE J,LIU C,GE Q.DFT study of CO2 adsorption and hydrogenation on the In2O3 surface[J].The Journal of Physical Chemistry C,2012,116(14):7817-7825.
[2]FANG X,HU X,JANSSENS-MAENHOUT G,et al.Sulfur hexafluoride(SF6)emission estimates for china:an inventory for 1990-2010and a projection to 2020[J].Environmental Science&Technology,2013,47(8):3848-3855.
[3]SULBAEK ANDERSEN M P,KYTE M,ANDERSEN S T,et al.Atmospheric chemistry of(CF3)2CF-CN:a replacement compound for the most potent industrial greenhouse gas,SF6[J].Environmental Science&Technology,2017,51(3):1321-1329.
[4]杨师斌.六氟化硫气体的危害与预防[J].重庆工商大学学报(自然科学版),2009,26(1):22-26.YANG Shibin.The harm and prevention of sulfur hexafluoride gas[J].Journal of Chongqing Technology and Business University(Natural Science Edition),2009,26(1):22-26.
[5]李兴文,赵虎.SF6替代气体的研究进展综述[J].高电压技术,2016,42(6):1695-1701.LI Xingwen,ZHAO Hu.Review of research progress in SF6 substitute gases[J].High Voltage Engineering,2016,42(6):1695-1701.
[6]汤昕,廖四军,杨鑫.SF6混合/替代气体绝缘性能的研究进展[J].绝缘材料,2014,47(6):18-22.TANG Xin,LIAO Sijun,YANG Xin.Research progress in insulating property of SF6 mixing/substituting gases[J].Insulating Materials,2014,47(6):18-22.
[7]肖淞,李祎,张晓星,等.CF3I及微氧条件下放电分解组分形成机理[J].高电压技术,2017,43(3):727-735.XIAO Song,LI Yi,ZHANG Xiaoxing,et al.Discharge decomposition components forming mechanism of CF3I under micro-aerobic condition[J].High Voltage Engineering,2017,43(3):727-735.
[8]ULLAH R,RASHID A,RASHID A,et al.Dielectric characteristic of dichlorodifluoromethane(R12)gas and mixture with N2/air as an alternative to SF6 gas[J].High Voltage,2017,2(3):205-210.
[9]刘英卫,钟世强,祁炯,等.六氟化硫气体回收处理技术及设备[J].电力设备,2008,9(8):14-17.LIU Yingwei,ZHONG Shiqiang,QI Jiong,et al.Sulfur hexafluoride gas recycling technology and equipment[J].Electric Power Equipment,2008,9(8):14-17.
[10]DERVOS C T,VASSILIOU P.Sulfur hexafluoride(SF6):global environmental effects and toxic byproduct formation[J].Journal of the Air&Waste Management Association,2000,50(1):137-141.
[11]张晓星,胡雄雄,肖焓艳.介质阻挡放电等离子体降解SF_6的实验与仿真研究[J].中国电机工程学报,2017,37(8):2455-2464.ZHANG Xiaoxing,HU Xiongxiong,XIAO Hanyan.Experimental and simulation study on degradation of SF6 by dielectric barrier discharge plasma[J].Proceedings of the CSEE,2017,37(8):2455-2464.
[12]夏胜国,何俊佳.非平衡等离子体燃烧强化[J].高电压技术,2007,33(10):109-113.XIA Shengguo,HE Junjia.Non-thermal plasma combustion enhancement[J].High Voltage Engineering,2007,33(10):109-113.
[13]FUJISHIMA A,HONDA K.Electrochemical photolysis of water at a semiconductor electrode[J].Nature,1972,238(5358):37.
[14]YAMADA Y,TAMURA H,TAKEDA D.Photochemical reaction of sulfur hexafluoride with water in low-temperature xenon matrices[J].The Journal of Chemical Physics,2011,134(10):104302.
[15]沈燕.强温室气体SF6、SF5CF3与CF4的等离子体降解与光降解过程的研究[D].上海:复旦大学,2008.SHEN Yan.Plasma degradation and photodegradation of strong greenhouse gas SF6,SF5CF3 and CF4[D].Shanghai,China:Fudan University,2008.
[16]SONG X,LIU X,YE Z,et al.Photodegradation of SF6 on polyisoprene surface:implication on elimination of toxic byproducts[J].Journal of Hazardous Materials,2009,168(1):493-500.
[17]HUANG L,DONG W,ZHANG R,et al.Investigation of a new approach to decompose two potent greenhouse gases:Photoreduction of SF6 and SF5CF3 in the presence of acetone[J].Chemosphere,2007,66(5):833-840.
[18]CARP O,HUISMAN C L,RELLER A.Photoinduced reactivity of titanium dioxide[J].Progress in Solid State Chemistry,2004,32(1/2):33-177.
[19]KUDO A,MISEKI Y.Heterogeneous photocatalyst materials for water splitting[J].Chemical Society Reviews,2009,38(1):253-278.
[20]MAEDA K.Photocatalytic water splitting using semiconductor particles:history and recent developments[J].Journal of Photochemistry&Photobiology C Photochemistry Reviews,2011,12(4):237-268.
[21]CHEN X,MAO S S.Titanium dioxide nanomaterials:synthesis,properties,modifications,and applications[J].Chemical Reviews,2007,107(7):2891-2959.
[22]CHEN X,LIU L,PETER Y Y,et al.Increasing solar absorption for photocatalysis with black hydrogenated titanium dioxide nanocrystals[J].Science,2011,331(6018):746-750.
[23]ZHANG J,ZHANG Y,LEI Y,et al.Photocatalytic and degradation mechanisms of anatase TiO2:a HRTEM study[J].Catalysis Science&Technology,2011,1(2):273-278.
[24]KIM J H,CHO C H,SHIN D H,et al.Abatement of fluorinated compounds using a 2.45 GHz microwave plasma torch with a reverse vortex plasma reactor[J].Journal of Hazardous Materials,2015,294:41-46.
[25]杨宇玲,郭新良,崔兆仑,等.紫外吸收光谱法检测SF6分解产物中的H2S[J].高电压技术,2018,44(8):2573-2579.YANG Yuling,GUO Xinliang,CUI Zhaolun,et al.Determination of H2S in SF6 decomposition products by ultraviolet absorption spectrometry[J].High Voltage Engineering,2018,44(8):2573-2579.
[26]DELLEY B.An all-electron numerical method for solving the local density functional for polyatomic molecules[J].Journal of Chemical Physics,1990,92(1):508-517.
[27]PERDEW J P,BURKE K,ERNZERHOF M.Generalized gradient approximation made simple[J].Physical Review Letters,1996,77(18):3865.
[28]DELLEY B.Hardness conserving semilocal pseudopotentials[J].Physical Review B,2002,66(15):155125.
[29]YANG Y,EVANS J,RODRIGUEZ J A,et al.Fundamental studies of methanol synthesis from CO2 hydrogenation on Cu(111),Cu clusters,and Cu/ZnO(0001[combining macron])[J].Physical Chemistry Chemical Physics,2010,12(33):9909-9917.
[30]ZUO Z J,LI N,LIU S Z,et al.Initial stages of oxidation for Cu-based catalysts using density functional theory[J].Applied Surface Science,2016,366:85-94.
[31]RAMOS M,DíAZ C,MARTíNEZ A E,et al.Dissociative and non-dissociative adsorption of O2 on Cu(111)and Cu ML/Ru(0001)surfaces:adiabaticity takes over[J].Physical Chemistry Chemical Physics,2017,19(16):10217-10221.
[32]YE J,LIU C,GE Q.DFT study of CO2 adsorption and hydrogenation on the In2O3 surface[J].The Journal of Physical Chemistry C,2012,116(14):7817-7825.