微波辐照下泡沫陶瓷担载镍催化剂上CH4/CO2重整制合成气反应

制备了吸波性良好的泡沫陶瓷担载镍的甲烷／二氧化碳重整催化剂,并考察了催化剂在微波场中的升温行为;研究了微波加热与常规加热对甲烷／二氧化碳重整制合成反应的影响,发现微波辐照下能有效地消除反应积炭;同时,在达到相同转化率和选择性时,微波加热方式下催化剂床层的温度远低于常规加热方式下催化床床层的温度;在微波加热方式下,８００℃反应时产物中Ｈ２／ＣＯ体积比接近于１。     

电场增强等离子催化反应由天然气合成碳二烃

本研究借助电场作用通过交流或直流等离子催化反应在常压、低下将天然气（甲烷）直接转一烃。甲烷被等离子场激活后直接和催化剂活性位作用生成乙烷、乙烯等碳二烃，由气相色谱在线分析其组成。考察了反应条件和催化剂的影响。得到了本实验较适宜反应条件下的碳二烃选择性在９０％以上的结果。     

氧对非平衡等离子体甲烷脱氢偶联反应的影响

氧对非平衡等离子体甲烷脱氢偶联反应的影响雷正兰陈栋梁刘万楹＊（中国科学院成都有机化学研究所天然气开放实验室６１００４１）甲烷偶联形成Ｃ２烃是甲烷直接转化的重要反应。非平衡等离子体条件下甲烷脱氢偶联是获得Ｃ２烃的一种新方法。不用催化剂，利用非平衡等离子...     

甲烷在微波等离子体下直接转化成C2烃

研究了非平衡微波等离子体中影响甲烷脱氢转化的几个因素，如功率、ＣＨ４／Ｈ２比和体系压力。在最佳条件下，甲烷转化率和乙炔的选择性分别达到７７．４６％和７４．０４％。     

微波场对固态氧离子导体上的甲烷氧化偶联的影响

研究了微波场下甲烷在具有δ－Ｂｉ２Ｏ３结构的固态氧离子导体上氧化偶联反应行为。与常规加热条件下的反应结果相比较，微波辐射下的反应有上特点：（１）在达到相同甲烷转化率时，微波辐照下所需床层温度要远低于常规加热条件下所需床层温度；（２）微波辐照下，甲烷氧化偶联产物中Ｃ２烃的选择性普遍较高，在低温区尤为突出。微波场下甲烷偶联产物乙烷、乙烯的再氧化得到一定程度的抑制，致使微波场下的甲烷氧化偶联反应通常有较     

微波—炭还原法处理一氧化氮的研究

报道了一种不需要催化剂而直接采用微波－炭还原技术处理一氧化氮（ＮＯ）的新方法。讨论了气体流量、反应温度、微波功率和施加微波时间对活性炭与一氧化氮发生还原反应的影响。比较了连续施加微波和间歇式施加微波方式下一氧化氮与活性炭发生化学反应转化为无公害的氮气（Ｎ２）和二氧化碳（ＣＯ２）的效率。研究结果表明，微波功率和反应器的类型及升温速率对一氧化氮与活性炭反应效率的影响较大。在连续施加微波时，一氧化氮与活     

脉冲电晕等离子体作用下甲烷“超平衡”转化制乙炔和氢

常温常压下将脉冲电晕等离子体作用于纯甲烷时, 其产物主要是乙炔和H₂. 当能量密度范围为194~1788 kJ/mol时, 可同时获得7%~30%的乙炔单程收率和6%~35%的H2单程收率. 该结果分别高于100 kPa, 1100 K温度下乙炔和H₂的热力学平衡收率(分别为5.1%和3.8%), 故脉冲电晕等离子体是在常温常压下实现甲烷“超平衡”转化制乙炔和氢的一种十分有效的手段. 在339~822 kJ/mol能量密度范围内, 脉冲电晕等离子体作用下纯甲烷转化产物的碳分布中, 乙炔占86%~89%, 乙烷和乙烯各仅占4%~6%, C₃约占2%, C₄约占1%. 将之与相同条件下纯乙烷、纯乙烯转化产物的碳分布比较可推知, 脉冲电晕等离子体作用下甲烷分子与荷能电子碰撞形成CH_x自由基后并行存在着三条形成乙炔的途径: 其一为直接形成乙炔; 其二为经初级产物乙烯脱氢形成乙炔; 其三为经初级产物乙烷脱氢形成次级产物乙烯再至乙炔.     

微波-炭还原法处理一氧化氮的研究

报道了一种不需要催化剂而直接采用微波-炭还原技术处理-氧化氮(NO)的新方法.讨论了气体流量、反应温度、微波功率和施加微波时间对活性炭与一氧化氮发生还原反应的影响.比较了连续施加微波和间歇式施加微波方式下一氧化氮与活性炭发生化学反应转化为无公害的氮气(N₂)和二氧化碳(CO₂)的效率.研究结果表明,微波功率和反应器的类型及升温速率对一氧化氮与活性炭反应效率的影响较大.在连续施加微波时,一氧化氮与活性炭反应率可达98％以上.此外,还对一氧化氮与活性炭反应后的产物进行了表征.     

微波场对固态氧离子导体上的甲烷氧化偶朕的影响

研究了微波场下甲烷在具有Bi2O3结构的固态氧离子导体上氧化偶联反应行为．与常规加热条件下的反应结果相比较,微波辐照下的反应有如下特点;（1）在达到相同甲烷转化率时,微波辐照下所需床层温度要远低于常规加热条件下所需床层温度;（2）微波辐照下,甲烷氧化偶联产物中C2烃的选择性普遍较高,在低温区尤为突出．微波场下甲烷偶联产物乙烷、乙烯的再氧化得到一定程度的抑制,致使微波场下的甲烷氧化偶联反应通常有较低的烯／烷比．     

光照和加热条件下Pt/TiO_2催化二氧化碳加氢(英文)

浸渍法制备了Pt负载量为0.5 to 2%的Pt/TiO2催化剂,考察它们在光照和加热条件下二氧化碳催化加氢性能.结果表明,二氧化碳加氢反应均可在Pt/TiO2的催化下进行,但在不同反应条件下加氢反应通过不同方式进行.在加热条件下,二氧化碳可转化为一氧化碳和甲烷,且在低温加热条件下一氧化碳是主产物(CO选择性为100%,250℃,0.5%Pt/TiO2).在1.5%Pt/TiO2催化剂上,当反应温度从250℃升高到450℃时,CH4的选择性由0增加到60.94%.同时,增加Pt的负载量也会导致CH4的选择性的增加.然而,在光照条件下,产物只有甲烷.CO2-TPD结果表明,二氧化碳通过羰基基团与作为吸附中心的Pt相连接.结合催化活性与表征结果,提出在光照条件下,反应可能以二氧化碳和氢气分别被光生电子活化反应生成甲酸中间体,随后经由甲酸加氢和脱水生成甲烷的机理进行.而在加热条件下,反应可能以二氧化碳首先吸附在催化剂表面形成羰基Pt物种,随后加氢生成一氧化碳,一氧化碳继续加氢生成甲烷的机理进行.     

正压、低温脉冲微波等离子体裂解天然气直接转化 制C2烃的研究

利用脉冲微波强化、扩展丝光等离子体反应装置,在常压和正压条件下,对低温脉冲微波等离子体裂解甲烷和氢气混合气制C2烃的反应进行了研究。考察了压力、微波功率、脉冲通/断时间以及氢气/甲烷比例、流量等参数对反应的影响。结果表明,在脉冲微波的作用下,常规高压放电形成的在空间呈非连续分布的丝状等离子体被强化和扩展成为连续分布的伞状等离子体,等离子体利用率和活性均得以大幅度提高;利用这种低温等离子体可以获得高的甲烷转化率,而且产物纯净,只有乙烯和乙炔;通过改变压力,还可能调节产物中C2H2/C2H4的物质的量比值,当气体总流量为300mL/min、物质的量比n(H2)/n(CH4)=2:1、压力为0.13MPa、微波峰值功率为120W、脉冲通/断比=400/400ms时,甲烷转化率可达59.2%,C2烃单程收率可达52%,其中乙炔单程收率达42.7%。     

Conversion of natural gas to C2 hydrocarbons via cold plasma technology

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.     

Conversion of Methane to C2 Hydrocarbons via Cold Plasma Reaction

Direct conversion of methane to C2 hydrocarbons via cold plasma reaction with catalysts has been studied at room temperature and atmospheric pressure. Methane can be converted into C2 hydrocarbons in different selectivity depending on the form of the reactor, power of plasma, flow rate of methane, ratio of N2/CH4 and nature of the catalysts. The selectivity to C2 hydrocarbons can reach as high as 98.64%, and the conversion of methane as high as 60% and the yield of C2 hydrocarbons as high as 50% are obtained. Coking can be minimized under the conditions of: proper selection of the catalysts, appropriate high flow rate of inlet methane and suitable ratio of N2 to CH4. The catalyst surface provides active sites for radical recombination.     

Highly effective methane conversion to aromatic hydrocarbons by means of microwave and rf-induced catalysis

Conversion of methane to higher hydrocarbon products, in particular, aromatic hydrocarbons has been achieved with good methane conversion and selectivity to aromatic products over heterogeneous catalysts using both high power pulsed microwave and rf energy. For example, under microwave irradiation > 85% conversion of methane and 60% selectivity to aromatics could be achieved. Cu, Ni, Fe and Al metallic materials are highly effective catalysts for the aromatization of methane via microwave heating; however, with a variety of supported catalysts the major products were C₂ hydrocarbons and the conversion of methane was low. The use of sponge, wire and net forms of these metal catalysts was found advantageous in effective methane conversion. The reactions are considered to be free radical in nature and to proceed through an intermediate stage involving formation of acetylene. The influence of catalyst nature and configuration, as well as the microwave and rf irradiation parameters on the reaction efficiency and product selectivity has been examined in both batch and continuous flow conditions.     

Conversion of natural gas to C_2 hydrocarbons through dielectric-barrier discharge plasma catalysis

The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 ml · min-1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons i     

Conversion of natural gas to C_2 hydrocarbons via cold plasma technology

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.     

Activation of methane in microwave plasmas at high pressure

Methane is converted to C2 products in a microwave plasma under pressure up to 400 torr at maximum plasma power of 100 W. Steam is introduced with methane into the plasma zone in order to suppress coke formation. Major products are C2 hydrocarbons. Small amounts of benzene are also formed. Very small amounts of some unusual highly unsaturated hydrocarbons are also formed. Oxygenated products are CO and CO₂. The conversion and yields are related to experimental variables by an empirical second order linear model. The conversion of methane ranges from 10 to 60%. The yield of C2 products ranges from 5 to 68%. The major C2 product is acetylene.     

Effect of La2O3／γ—Al2O3 Catalyst on the Activation of CH4 and CO2 to C2 Hydrocarbons under Non—equilibrium Plasma

In the reaction of methane and carbon dioxide to C2 hydrocabons under non-equilibrium plasma, methane conversion was decreased,but selectivity of C2 hydroxarbons was increased when using La2O3/γ-Al2O3 as catalyst. So the yield of C2 hydrocarbons was higher than using plasma alone. The synergism of La2O3/γ-Al2O3 and plasma gave methane conversion of 24.9% and C2 yield of 18.1%. The distribution of C2 hydrocarbons changed when Pd-La2O3/γ-Al2O3 was used as catalyst,the major C2 product was ethylene.     

滑动弧电极放电等离子体作用甲烷制C2烃的工艺

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。