【作者】 程文；

【导师】 李振花；

【作者基本信息】 天津大学 ， 化学工艺， 2007， 硕士

【摘要】 石油资源的日益短缺使人们对储量丰富的天然气资源的开发利用越来越重视。作为天然气的主要成分甲烷,其转化利用成为天然气转化的关键。等离子体是一种十分有效的分子活化手段,非平衡等离子体利用其特殊的非平衡性在甲烷转化方面具有独特的优势。本文对非平衡等离子体强化甲烷转化制碳二烃的过程进行了研究。在刀刃状旋转电极反应器中,考察了添加气、反应器参数以及电源参数对反应的影响规律。研究表明:H2,N2和Ar的加入均有利于甲烷转化率的提高,同时H2还能有效的抑制积碳;较小的放电间距及不锈钢内电极有利于甲烷转化;电源参数对反应的影响最终可归结为电流的影响,脉冲参数对反应的影响并不明显。通过比较刀刃状旋转电极反应器与介质阻挡反应器的实验结果,对甲烷转化的反应机理进行了推测。所得结果为:在刀刃状旋转电极反应器中,甲烷分子大部分被解离为CH和C自由基,反应的主要产物是乙炔和少量乙烯,积碳较多;而在介质阻挡放电反应器中,甲烷大部分被解离为CH3自由基,反应的主要产物为乙烷和丙烷,几乎没有积碳产生;同种放电类型的反应器中,产物分布的整体趋势是一致的;刀刃状旋转电极反应器中甲烷转化速率要远大于介质阻挡反应器中的甲烷转化速率。另外,对滑动弧光放电等离子体用于甲烷转化进行了初步探索。实验结果表明滑动弧光反应器中能耗较低,适宜大流量气体的反应,对甲烷等离子体转化的工业化放大很有前途。更多还原

【Abstract】 With the gradually decrease of petroleum resources, more and more attention have been paid to the exploitation and application of natural gas. As the major component of nature gas, methane conversion became the highlight of natural gas utilization. It is well known that plasma is a very effective method to activate small molecules like methane and carbon dioxide. Furthermore, the low temperature plasma is predominantly utilized in methane conversion for its unique non-equilibrium character.In this thesis the process of methane conversion to C2 hydrocarbons with non-thermal plasma was studied. The effects of additive gases, parameters of the reactor and power supply were investigated in the multi-edge rotary electrode reactor. The results indicated that methane conversion was increased with the additive gases and the carbon deposited could also be effectively removed by hydrogen addition. Good results were obtained with small discharge distance and stainless steel inner electrode. The effects of parameters of power supply could be attributed to the electric current and the parameters of pulse have little effect on the reaction.The mechanism of methane conversion was proposed through comparing the results from the multi-edge rotary electrode reactor and dielectric barrier discharge (DBD) reactor. It was found that in the multi-edge rotary electrode reactor, methane was largely decomposed to CH and C radicals, which resulted in large amount of acetylene and a little ethane as products with lots of carbon deposited. While in the DBD reactor, methane was largely decomposed to CH3 radical which resulted in the main products of ethane and propane with little carbon deposited. With the same reactor type, the products distribution was almost constant. The methane conversion rate in the multi-edge rotary electrode reactor was much higher than that in DBD.Additionally, methane conversion in gliding arc discharge was elementary investigated. The results showed methane can be converted at lower input power and high gas flow rate, which shows an attractive outlook for the industrialization of methane conversion.更多还原