甲烷制乙烯技术进展

介绍了当下几种主要的甲烷制乙烯的技术、原理及这几种技术的研究进展。甲烷制乙烯主要分为多步法和一步法,其中多步法包含甲烷经甲醇制乙烯、经合成气费托合成制乙烯;一步法包含甲烷氧化偶联制乙烯技术和甲烷直接无氧脱氢制乙烯技术。截至目前,甲烷经甲醇制烯烃已经成功工业化,甲烷氧化偶联制乙烯接近工业化,但仍需要加大工程化研发力度,争取早日实现工业化。     

甲烷液相部分氧化制甲醇中溶剂介质的研究进展

甲烷液相转化具有反应条件温和、能耗低、投资少等优点,研究甲烷液相部分氧化制甲醇对实现天然气的直接转化和利用具有极为重要的战略意义。本文介绍了甲烷液相部分氧化制甲醇反应中有关反应溶剂介质的研究进展,详细叙述了各种酸性介质、水以及乙腈溶剂在甲烷部分氧化制甲醇中的应用,总结了不同溶剂介质下的反应机理、催化剂、溶剂浓度等对甲烷转化的影响,探讨了溶剂在甲烷液相部分氧化中的作用,指出依据溶剂介质的性质和作用,开发环境友好、反应条件温和、转化效率高的优良新型溶剂是甲烷液相部分氧化制甲醇的重要研究方向。     

膜催化技术用于甲烷转化反应的研究进展

介绍了膜催化技术在甲烷转化反应中的应用,这些过程包括甲烷氧化偶联反应制乙烯,甲烷部分氧化制甲醇,甲烷水蒸气重整制合成气等,通过膜催化反应与传统催化反应的比较,揭示了膜催化技术的优点。     

微波场中的甲烷部分氧化制合成气

介绍了微波场中甲烷部分氧化制合成气反应的原理及特性,对甲烷部分氧化制合成气反应的催化剂在微波场中的性能进行了简要介绍和分析,表明了甲烷部分氧化的微波反应技术具有较好的工业应用前景。     

甲烷直接转化的研究现状与展望

介绍了甲烷直接转化的国内外研究现状,系统阐述了近年来甲烷直接氧化制甲醇、甲醛,氧化偶联制乙烯,甲烷的芳构化,甲烷无氧同系化的研究进展。对新型纳米结构催化剂,微波辅助下的催化转化,以离子液体为介质的反应系统研究甲烷直接转化的新领域作了介绍。     

天然气甲烷部分氧化制合成气的研究进展

甲烷部分氧化制合成气是高转化率、高选择性、高空速、低H2/CO、温和的放热反应,综述了近几年来甲烷部分氧化制合成气的催化剂、反应机理及活性中心的研究进展及反应中的存在问题。     

甲烷常压非催化部分氧化制合成气研究

考察了常压下甲烷非催化部分氧化制合成气过程中,甲烷转化率、气体产物产率以及积炭率随反应器温度、进气配比、原料气流量变化的影响。通过考察反应器温度对制备合成气过程的影响结果,分析了甲烷非催化部分氧化制合成气过程的反应机理。     

甲烷制乙烯技术研究进展

为了改变乙烯生产原料过分依赖于石油资源的状况,各国积极开展了对原油、生物资源、煤和甲烷等原料制乙烯新工艺的研究开发,乙烯生产原料多样化的趋势日渐明朗。对甲烷直接制乙烯技术——甲烷氧化偶联制乙烯和甲烷无氧催化制乙烯技术进行综述,并对其关键技术进行分析。     

甲烷氧化偶联反应制乙烯的研究进展

介绍了近年来甲烷氧化偶联制乙烯(OCM)过程的催化剂、反应机理、动力学及工程放大涉及的反应工艺、反应器等方面的研究进展,对甲烷氧化偶联法和传统裂解法的经济性进行了对比,指出目前甲烷氧化偶联制乙烯工艺的选择性和转化率还较低,因此成本上比裂解制乙烯要高。最后,对催化剂、工程放大、生产流程和分离方案等方面的研究中存在的问题进行了分析。     

碘催化氧化甲烷制甲醇催化剂

碘催化氧化甲烷制甲醇催化剂美国南加利福尼亚州大学洛克尔烃研究所研究人员发现 ,碘溶解在发烟硫酸中形成的溶液是甲烷低温氧化的有效催化剂。碘发烟硫酸溶液催化甲烷转化形成硫酸氢甲酯 ,后者再与水反应很容易生成甲醇。据称 ,这是迄今报道的在 2 0 0℃以下将甲烷转化成一种甲基产物的最简单的催化体系。其甲烷转化率在 40 %以上 ,硫酸氢甲酯选择性在 95 %以上 ,在已报道的数据中属最高的一类。而且 ,这种氧化体系与其他甲烷氧化体系不同 ,不需要过氧化氢等昂贵的催化剂碘催化氧化甲烷制甲醇催化剂     

Microbial aerobic oxidation of methane in paddy soil

The microbial aerobic oxidation activity of methane, the population of aerobic methane oxidizers and the factors influencing the activity of methane oxidation were investigated in three types of paddy rice soil in Zhejiang Province, China. Methane oxidation activity was different among Huangsong paddy soil developed from fluvo-aquic soil, Old huangjinni paddy soil developed from quaternary red clay and Qingzini paddy soil developed from coastal saline soil. The Huangsong paddy rice soil showed the highest activity of methane oxidation. Different methane oxidation activity and populations of methane-oxidizing bacteria were found in various Huangsong soil samples that had different plant-cover. Methane oxidation returned to the same level after these soil samples were incubated and induced by extra added methane. The population of methane oxidizing bacteria was at maximum within the peak-tillering, heading and flowering stages, during which the largest population of methanogenic bacteria also appeared. Temperatures from 25 to 35 °C and pH from 6 to 8 were the optimum conditions for aerobic oxidation of methane in paddy rice soil. Soil particle size also affected the activity of methane oxidation.     

化学链催化甲烷氧化反应研究进展

甲烷作为天然气的主要组成成分,其有效利用具有重要的现实意义。本文首先介绍了甲烷转化工艺,系统地比较了传统甲烷氧化与化学链催化甲烷氧化工艺,提出化学链重整技术作为一种应用于甲烷氧化反应的新技术,提供了一个多功能平台,以清洁及有效的方式转换燃料。然后,介绍了应用于此技术的催化剂研究现状,重点关注具有高储氧性能、催化性能以及低合成成本特点的钙钛矿复合氧化物,特别综述了利用机器学习方法高通量筛选钙钛矿氧化物催化剂的理论计算工作。最后,系统讨论了钙钛矿氧化物对化学链催化甲烷氧化反应性能的影响规律,依据实验和密度泛函理论计算研究结果,对催化剂颗粒尺寸、金属离子价态、氧空穴形成能以及氧浓度同催化性能之间的关系进行了分析,提出钙钛矿氧化物催化甲烷氧化反应的关键影响因素,为钙钛矿氧化物催化剂的筛选提供理论支撑。     

An investigation on the reaction mechanism for the partial oxidation of methane to synthesis gas over platinum

The partial oxidation of methane to synthesis gas has been investigated by admitting pulses of pure methane, pure oxygen and mixtures of methane and oxygen to platinum sponge at temperatures ranging from 973 to 1073 K. On reduced platinum the decomposition of methane results in the formation of surface carbon and hydrogen. No deposition of carbon occurs during the interaction of methane with a partly oxidised catalyst. Oxygen is present in three different forms under the conditions studied: platinum oxide, dissolved oxygen and chemisorbed oxygen species. Carbon monoxide and hydrogen are produced directly from methane via oxygen present as platinum oxide. Activation of methane involving dissolved oxygen provides a parallel route to carbon dioxide and water. Both platinum oxide and chemisorbed oxygen species are involved in the oxidation of carbon monoxide and hydrogen. In the presence of both methane and dioxygen at a stoichiometric feed ratio the dominant pathways are the direct formation of CO and H₂ followed by their consecutive oxidation. A Mars-van Krevelen redox cycle is postulated for the partial oxidation of methane: the oxidation of methane is accompanied by the reduction of platinum oxide, which is reoxidised by incorporation of dioxygen into the catalyst.     

覆盖层氧气消耗通量模型及甲烷氧化能力预测

填埋场覆盖层生物气扩散规律和甲烷氧化能力的评估是甲烷减排研究的重要组成部分。以数值模拟方法分析了氧气在覆盖层中的扩散规律,得到了指数方程形式的氧气扩散模型(R²范围0.8941～0.9975);通过检测有机碳和甲烷浓度变化进一步考察了模拟覆盖层不同深度的甲烷氧化能力,证实了在0.05～0.25 m范围内甲烷氧化活性最高;以Fick定律和轴向扩散模型推导了模拟覆盖层中氧气消耗通量模型,该模型计算得到的氧气消耗通量与覆盖层中微生物甲烷氧化经验方程相比无显著差异;结合以上模型推演出覆盖层甲烷消耗通量模型,与实际检测值相比,预测结果理想(R²=0.9983)。该成果可为揭示填埋场覆盖层生物气扩散规律、强化甲烷氧化能力以及预测甲烷排放提供新的思路和理论依据。     

Manganese oxide catalyzed methane partial oxidation in trifluoroacetic acid: Catalysis and kinetic analysis

Direct oxidation of methane to methanol has been studied for decades, and has yet to be commercialized. Three years ago, UOP LLC, a Honeywell Company, started a government co-sponsored project (NIST/ATP Award 70NANB4H3041) for selective liquid phase oxidation of methane to methanol. Recently we have discovered an efficient methane oxidation by manganese oxide. When used as stoichiometric oxidant, quantitative metal oxide-based yield was observed for methane oxidation. The spent catalyst activity can be 100% regenerated with air under basic conditions. A high methane-based yield (36%) with high selectivity (>95%) was achieved when manganese oxide was used in catalytic amount in the presence of air for methane oxidation. Our online GC analysis showed that catalytic methane oxidation occurs with two-stage reaction kinetics with constant reaction rate at the active stage, which can be explained by a low steady-state active catalyst concentration as observed by in situ UV–vis spectrometer.     

Biocatalytic methane oxidation

The kinetics of biocatalytic methane oxidation should be known to make use of this process in environmental biotechnology. Here, biocatalytic methane oxidation is described using multisubstrate kinetic models (studies were performed at 30°C). The dependence of the specific growth rate of microorganisms (biomass buildup per unit time divided by the amount of biomass) on the methane and oxygen concentrations in the culture liquid is best describable in terms of the Moser-Moser multisubstrate kinetic model. The methane and oxygen consumption coefficients and the carbon dioxide yield coefficient have been determined. These data are used to construct a mathematical model for heterogeneous biocatalytic methane oxidation. With this model, it is possible to predict the behavior of the biocatalytic system under given conditions.     

激光催化氧化甲烷合成化合物的研究进展

天然气储量丰富,日益成为重要的清洁能源之一,而从其主要成分甲烷合成高附加值化合物更是研究前沿。由于甲烷结构稳定,CH键能很高,因而活化甲烷需要的条件非常苛刻。本文首先介绍了普通光催化氧化甲烷合成化合物的反应原理、研究进展、催化反应器和存在不足,然后综述了激光催化氧化甲烷合成化合物的反应原理、研究进展和催化反应器。指出激光光源具有提高光催化剂量子效率和缩短催化反应时间等诸多优势,接下来在深入研究激光催化反应机理的基础上,通过设计科学合理的激光反应体系,并遴选高效的光催化剂,有望显著提升包括甲烷氧化在内的激光催化反应性能,从而具有重要的学术意义和实践价值。今后的重点研究方向是通过激光催化氧化的方法使甲烷在温和的条件下活化,并合成高附加值化合物。     

Some features of methane oxidation at high pressures

Some features of mechanism of homogeneous oxidation of methane under high pressures are discussed. The mechanism of formic acid formation is suggested. Commercial aspects of methanol production by methane direct oxidation are shortly outlined.