共查询到19条相似文献,搜索用时 140 毫秒
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脉冲电晕等离子体作用下甲烷偶联反应--Ⅰ.无氧气氛下 总被引:2,自引:0,他引:2
在常温常压下,对脉冲电晕等离子体应用于甲烷无氧气氛下脱氢偶联反应进行了研究.考察了脉冲电压极性和等离子体注入能量对甲烷脱氢偶联反应的影响,并引入能量效率对等离子体能量与甲烷脱氢偶联反应的耦合进行了讨论.结果表明,正电晕的能量效率高于负电晕.在正电晕条件下,当脉冲重复频率为 66 Hz和能量密度为 1788kJ/mol时,甲烷转化率可达44.6%, C_2烃单程收率可达31.6%,其中乙炔单程收率达30.1%.甲烷转化率与能量密度P/F的关系满足-ln(1—X)=k(P/F).在实验考察的能量范围内,C_2烃收率与能量密度P/F呈顺变关系,但能量效率随能量密度的增加而降低. 相似文献
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电晕放电二氧化碳冷等离子体转化特性研究 总被引:5,自引:3,他引:2
在常压、室温条件下利用电晕放电使二氧化碳通过冷等离子体反应分解为一氧化碳和氧气,由四极质谱在线定量在分析产物组成。考察反应条件(电晕类型、能量密度、气体流量等)对反应转化率的影响,分析了该反应的能量效率。当放电功率为40W、CO2流量为30mL.min^-1时,正电晕等离子体CO2分解反应的转化率为15.2%;CO2,专座经率随体系能量密度的增加上升,随反应时间的增加而增大,当CO2流量为90mL.min^-1、正电晕放电功率为37.6W时,反应体系的能量效率为5.89%。实验发现,正电晕放电时CO2的转化率高负电晕的转化率。 相似文献
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采用刀片式不锈钢电极放电反应器,以Ar气为稀释气,研究了等离子体作用下甲烷转化制C2烃的工艺条件。考察了CH4流量、高频电源输入电压和电极间距等参数对甲烷转化率、C2烃选择性、收率和反应表观能耗的影响。结果表明,增加CH4流量,表观能耗随之降低;当输入电压和电极间距较小时,甲烷转化率随输入电压和电极间距的增大而增大,但输入电压和电极间距过大时,C2烃收率明显下降,积碳严重。在CH4流量14 mL/min、Ar气流量60 mL/min、高频电源输入电压22 V、电流0.44 A、电极间距4 mm的优化条件下,甲烷最高转化率为43.1%,C2烃收率、选择性和表观能耗分别为40.1%、93.2%和2.41 MJ/mol。C2烃中不饱和烃的体积分数可达95%以上。 相似文献
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在常温、常压下,较系统地研究了CO2在脉冲电晕等离子体条件下的活化与转化,考察了反应器参数、脉冲成形电容、应用电压、气体流量、电晕极性对二氧化碳转化的影响。在本实验条件下,最佳反应器的有效长度为125mm,内径为22mm。二氧化碳转化率和一氧化碳产率随应用电压的增加而增加。另外,随着应用电压的增加,脉冲反应器的能量利用效率反而降低。随着气体流量的增大,二氧化碳的转化率及一氧化碳的产率下降。γ-Al2O3的存在大大促进了二氧化碳的转化,CO2的最高转化率达23%。由于γ-Al2O3在物化性质方面的特性,γ-Al2O3的存在对二氧化碳的转化有重要的作用。研究表明:脉冲电晕放电-催化转化CO2为CO是可行的。 相似文献
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TS分子筛的催化氧化性能研究 Ⅱ.丙烯的环氧化 总被引:3,自引:1,他引:3
研究了TS分子筛用于过氧化氢氧化丙烯制环氧丙烷的催化过程,考察了TS分子筛的组成、预处理条件、分子筛中氧化钛的存在对催化环氧化反应的影响.研究表明,TS-1的活性优于TS-2,分子筛中TiO2的存在会加快过氧化氢的分解,降低产物环氧丙烷的收率.对操作工艺条件的研究表明,反应液以中性为好,偏酸或偏碱都会使产物水解产生丙二醇,降低产物的选择性.在28℃、0.4MPa的条件下反应1h,过氧化氢的转化率和环氧丙烷的选择性可分别达到>70%和>95%. 相似文献
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大气压旋转螺旋状电极辉光放电等离子体催化甲烷偶联 总被引:2,自引:0,他引:2
采用新研制的具有旋转螺旋状电极的大气压辉光放电等离子体反应器催化甲烷偶联制碳二烃. 实验采用铜电极和不锈钢电极分别考察了输入电场峰值电压和甲烷、氢气进料流量等参数对甲烷转化率和碳二烃收率、选择性的影响. 在长时间连续反应无明显积碳的情况下, 最佳试验结果是电极材料为金属铜, 进料流量为60 mL•min-1, V(CH4 )/V(H2)=1的条件下, 输入电场峰值电压为2.3 kV时, 甲烷转化率为70.64%, 碳二烃单程收率及其选择性分别为69.85%和 99.14%. 相似文献
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作为一种重要的化工原料,环氧丙烷年产量近千万吨,然而目前工业上制备环氧丙烷的方法仍然面临着成本高、副产物多以及污染严重等问题。直接氧气氧化法进行丙烯环氧化因为具有原子经济、环保等优点受到了越来越多的关注。但是,催化过程中丙烯的α-H和环氧丙烷都具有很高的活性,使得在高转化率的条件下提升环氧丙烷选择性成为一个巨大的挑战。研究者们发现相较于其他币族金属,Cu基催化剂表现出更优异的丙烯直接环氧化反应性能。本综述总结梳理了近年来关于Cu基催化剂催化丙烯直接环氧化反应的研究成果,聚焦于Cu基催化剂改性方法,并对Cu基催化剂依然存在的问题和挑战进行深入探讨。 相似文献
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In non‐catalytic direct conversion of propylene with oxygen to propylene oxide by using dielectric barrier discharge under conditions of room temperature and atmospheric pressure, the selectivity to propylene oxide from propylene was >30% at propylene conversion ranging from 3.91% to 81.72%. 相似文献
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等离子体-催化剂耦合作用下CO2的甲烷化研究 总被引:3,自引:0,他引:3
常温常压下,利用脉冲电晕等离子体与Ni/γ-AI2O3催化剂协同作用CO2加氢转化生成甲烷,考察了催化剂担载量、放电参数、工艺参数等对反应的影响,并探讨了其反应机理。结果表明,在等离子体与催化剂协同作用下,CO2加氢生成CH4,CO2转化率在催化剂一定担载量范围内随担载量的增加而增加;脉冲电压峰值、重复频率、进气方式、空速等反应有重要影响;相同条件下,等离子体-催化法优于化学催化法。 相似文献
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Lee Dae-Won Lee Jung-Hyun Chun Bae-Hyeock Lee Kwan-Young 《Plasma Chemistry and Plasma Processing》2003,23(3):519-539
The direct hydroxylation of benzene using molecular oxygen by atmospheric pulse DC corona discharge was investigated. The conversion of benzene increased with the increase of oxygen content and input voltage but the selectivity of phenol decreased due to the formation of polymerized products. The reactivity was also influenced by the kind and content of background inert gas. By using argon as background gas, we could get 2.2% of phenol yield at 60°C and 1 atm with energy consumption of 50 W. The strategy of reductive oxidation, which added hydrogen to the reactant, was not favorable to the phenol formation in this reaction system. The polymerized product showed the oligomeric character and the analysis of its chemical structure with FT–IR was presented. 相似文献
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The plasma technology served as a tool in unconventional catalysis has been used in natural gas conversion, because the traditional catalytic methane oxidative coupling reaction must be performed at high temperature on account of the stability of methane molecule. The focus of this research is to develop a process of converting methane to C2 hydrocarbons with non-equilibrium plasma technology at room temperature and atmospheric pressure. It was found that methane conversion increased and the selectivity of C2 hydrocarbons decreased with the voltage. The optimum input voltage range was 40-80 V corresponding to high yield of C2 hydrocarbons. Methane conversion decreased and the selectivity of C2 hydrocarbons increased with the inlet flow rate of methane. The proper methane flow rate was 20-40 ml/min (corresponding residence time 10-20 s). The experimental results show that methane conversion was 47% and the selectivity of C2 hydrocarbons was 40% under the proper condition using atmospheric DBD cold plasma technology. It was found that the breakdown voltage of methane VB was determined by the type of electrode and the discharge gap width in this glow discharge reactor. The breakdown voltage of methane VB,min derived from the Paschen law equation was established. 相似文献
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《Journal of Energy Chemistry》2010,(4)
The plasma technology served as a tool in unconventional catalysis has been used in natural gas conversion,because the traditional catalytic methane oxidative coupling reaction must be performed at high temperature on account of the stability of methane molecule.The focus of this research is to develop a process of converting methane to C2 hydrocarbons with non-equilibrium plasma technology at room temperature and atmospheric pressure.It was found that methane conversion increased and the selectivity of C2 hydrocarbons decreased with the voltage.The optimum input voltage range was 40-80 V corresponding to high yield of C2 hydrocarbons.Methane conversion decreased and the selectivity of C2 hydrocarbons increased with the inlet flow rate of methane.The proper methane flow rate was 20-40 ml/min (corresponding residence time 10-20 s).The experimental results show that methane conversion was 47% and the selectivity of C2 hydrocarbons was 40% under the proper condition using atmospheric DBD cold plasma technology.It was found that the breakdown voltage of methane VB was determined by the type of electrode and the discharge gap width in this glow discharge reactor.The breakdown voltage of methane VB,min derived from the Paschen law equation was established. 相似文献
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Yun Yang 《Plasma Chemistry and Plasma Processing》2003,23(2):283-296
The direct non-oxidative conversion of methane to higher hydrocarbons in non-thermal plasma, namely dielectric barrier discharge and corona discharge, has been investigated experimentally at atmospheric pressure. In dielectric barrier discharge, the methane is mainly converted to ethane and propane with small amounts of unsaturated and higher hydrocarbons. While in corona discharge, methane was activated mainly to acetylene with small amount of other higher hydrocarbons. Decreasing the gas flow or increasing power input will improve the methane conversion and product yields. It is found that the methane conversion and main product yield against the input specific energy were special functions in both dielectric barrier discharge and corona discharge, independent of the reactor size, and whether fixing flow rate or power input and changing the power input or flow rate. The corona discharge is a promising alternative method for methane conversion to produce acetylene and hydrogen at low temperature. 相似文献
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Sergey Kudryashov Andrey Ochered’ko Andrey Ryabov Galina Shchyogoleva 《Plasma Chemistry and Plasma Processing》2011,31(5):649-661
Oxidation of propylene with oxygen, air and a mixture of nitrogen–oxygen in a barrier discharge is investigated. The selectivity
towards formation of propylene oxide in pure oxygen is shown to be as high as 45 wt% and the propylene conversion ratio is
found to be 12.9 wt%. In the oxidation with air, the propylene oxide selectivity is 23 wt%, while the conversion is 7.5 wt%.
The values of propylene conversion and selectivity towards formation of propylene oxide in a barrier discharge are consistent
with those obtained by the thermocatalytic methods for production of propylene oxide. 相似文献