【作者】 杨建涛；

【导师】 汪大翚； 施耀；

【作者基本信息】 浙江大学 ， 环境工程， 2010， 博士

【摘要】 工业的迅猛发展以及人们对生活质量的要求越来越高,恶臭污染（尤其含硫恶臭气体嗅阈值低、毒性大）治理日益受到重视。脉冲电晕低温等离子体技术具有工艺流程简单、效率高和适用范围广等优点在治理含硫恶臭气体方面已成为研究的热点之一。本文研究了反应器串、并联模式以及活性炭纤维吸附协同脉冲电晕降解硫化氢的过程。采用脉冲电晕在介质阻挡（DBD）反应器对乙硫醇和甲硫醚降解及副产物产生进行了研究,对降解机理和反应动力学进行了探讨。论文取得了以下主要结论:1.采用反应器串联和并联模式相对于单一反应器模式,在相同的充电电压下,其放电特性为峰值电压降低、脉冲上升前沿变缓、脉冲宽度增加。在充电电压小于9kV,串联模式和并联模式反应器阻抗比由4.5降低到2.9,电源的能量效率提高约10%。在充电电压分别为13kV和14kV时,串、并联模式H₂S去除率接近100%,而单一模式则只达到88%和91%。处理进口浓度为200mg/m³的H₂S,串、并联模式及单一模式能量消耗指标分别,为43J/L、51J/L、68J/L,且串联模式与并联模式产生的O₃浓度有所降低。2.采用脉冲电晕-活性炭纤维协同降解硫化氢,在相同充电电压下,复合系统中H₂S的去除率比单一脉冲电晕反应器有很大提高,复合系统的能耗（EC值,降解1分子污染物所需能量）比单一脉冲电晕有所降低,而能量利用率（EY值）有所提高。相对于单一活性炭纤维,在脉冲电晕作用下,ACF对硫化氢的穿透时间最大延长16倍;ACF对硫化氢的降解吸附容量在6kV时提高4.2倍,对O₃的吸附分解容量也提高1.6倍;活性炭纤维能够控制脉冲电晕反应器中生成的副产物如SO₂、O₃和NO_x。3.脉冲电晕-活性炭纤维协同体系在充电电压为6kV时H₂S的去除率比单一脉冲电晕时提高15%,并且H₂S的去除率达到88%时,与单一脉冲电晕在7kV时硫化氢的降解率相当,能耗指标EC值减少21eV/molecules,EY值提高1.7mg/kJ;组合系统比单一脉冲电晕能耗节省26.5%。4.脉冲电晕在DBD反应器中,重复频率、峰值电压提高,甲硫醚（CH₃SCH₃）和乙硫醇（C₂H₅SH）的去除率增大,在适当条件下最终其去除率都能接近100%,但能量利用率在重复频率100pps时最大,分别达到0.338mg/kJ和0.223mg/kJ。增大污染物初始浓度和气体流量,在相同的峰值电压下CH₃SCH₃和C₂H₅SH的去除率都有所降低,但绝对去除量和EY却增大。气体湿度对CH₃SCH₃的去除率有重大影响,增大湿度CH₃SCH₃去除率提高很大,在相对湿度超过30%时,峰值电压达到起晕电压时CH₃SCH₃基本得到去除,能量利用率可达到2.87mg/kJ。O₂含量为5%时,在相同的峰值电压下CH₃SCH₃的去除率最高,能量利用率EY值最大,在27.3kV时达到0.295mg/kJ。增大或者减小O₂含量,能量利用率都降低。5.CH₃SCH₃的初始浓度增大,O₃、NO_x的生成浓度降低;SO₂的浓度随CH₃SCH₃的初始浓度增大而增大,但其生成SO₂的选择性S_B却有所降低;气体湿度为6%,14%时,对O₃的生成有促进作用,对NO_x的生成影响不大;提高气体湿度,SO₂生成浓度增大,但S_B降低。在相同峰值电压下,SO₂生成浓度随O₂含量的增大而增大,O₂含量大,硫元素的氧化较为彻底,生成SO₂的S_B增大。6.通过产物分析,对CH₃SCH₃和C₂H₅SH的降解机理进行了初步推测,认为在脉冲电晕放电处理污染物时,自由基的反应是主要的中间步骤。通过对CH₃SCH₃降解动力学模型进行拟合,认为其降解过程符合没有自由基终止的动力学模型。更多还原

【Abstract】 The pollution and control techniques of odors are received increasing attention with the industrial developing and the living quality required more and more highly, especially the sulfide odors are with lower odor threshold value and larger toxicity. Pulsed corona（non-thermal plasma） technique is of focus on the treatment of sulfide odors,which has high destruction efficiency,simply installed and widely applicable. In this paper,serial and parallel reactors,activated carbon fibers（ACF） adsorption are used to treat H₂S.And we studied to decompose the dimethyl sulfide and ethanethiol in DBD reactor,discussed the byproduces decomposition mechanisms and kinetics. The main conclusions of this work are drawn:1.The peak voltage decreases,pulse rise time becomes slower and pulse width increases at the same of discharge voltage with serial and parallel reactors compared with single reactor.At low discharge voltage（＜9 kV）,the impedance ratio decreases from 4.5 to 2.9,and energy yield improves about 10%with serial and parallel modes. H₂S removal efficiency reaches nearly 100%at discharge voltage 13 kV and 14 kV with serial modes and parallel modes,respectively,while H₂S removal efficiency is only 88%and 91%at the same discharge voltage with single mode.When the removal amounts of H₂S is 200 mg/m³,the energy consumption index is 43 J/L,51 J/L,68 J/L with single,parallel and serial modes,respectively.O₃ concentration increases at the same of discharge voltage with serial and parallel modes.2.Decomposition of H₂S was carried out by the combination of pulse corona and ACF.The addition of ACF improves effectively H₂S removal efficiency,the EC value reduces and EY value increases at the same of discharge voltage.Compared to single ACF adsorption,the breakthrough time of ACF for H₂S is prolonged the most of 16 times with pulsed corona,the adsorption and decomposition capacity improves 4.2 times for H₂S and 1.6 times for O₃ at 6 kV,During pulse corona reactor,the byproducts,such as O₃,SO₂,NO_x can be controlled and aren’t detected before the breakthrough time of ACF for H₂S.3.The H₂S removal efficiency is up to 88%,and improves 15%at 6 kV in synergetic system of pulse corona and ACF adsorption compared with single pulsed corona,which is equivalent with single pulse corona at 7 kV.The EC value reduces 21 eV/molecules and EY value increases 1.7 mg/kJ,the energy consumptionm at 6 kV reduces 26.5%. 4.The removal efficiencies of CH₃SCH and C₂H₅SH increase with the pulsed frequency and peak voltage increasing in DBD reactor,and can reach 100%at appropriate conditions.But the energy yields are the most and achieve 0.338 mg/kJ, 0.223 mg/kJ at 100 pps,respectively.When the initial concentrations and flow rate increase,the removal efficiencies of CH₃SCH and C₂H₅SH decrease at the same peak voltage.However,the absolute removal amounts and energy yield rise.The gas humidity has great effect on the CH₃SCH₃ removal efficiency;furthermore the removal efficiency improves effectively with the humidity increasing.The CH₃SCH₃ achives to remove completely and EY gets 2.87 mg/kJ at the critical corona voltage when the gas humidity exceeds 30%.When the O₂ content is 5%,the CH₃SCH₃ removal efficiency reaches the most and the energy yield is the most of 0.295 mg/kJ at the same voltage.The energy yield reduces when the O₂ content both increases and decreases.5.The O₃,NO_x,concentration decrease and SO₂ concentration increases with CH₃SCH₃ initial concentration increasing,but the SO₂ selectivity（S_B） slows down. The gas humidity is 6%and 14%,which promotes the production of O₃ and has little effect on NO_x.The SO₂ concentration improves with initial concentration increasing, but SO₂ selectivity becomes lower.At the same peak voltage,O₂ content improves the production of SO₂,the SO₂ selectivity increases because the S element is oxidized relatively completely.6.By means of products analysis,the decomposition mechanisms of CH₃SCH₃ and C₂H₅SH are considered that the free radical reaction is major intermediate process. Through the kinetics model fitting of CH₃SCH₃ decomposition,it is considered that CH₃SCH₃ decomposition conforms to no significant radical terminations model.更多还原