Brief Overview of the Partial Oxidation of Methane to Synthesis Gas

A review of the main developments in the partial oxidation of methane to synthesis gas since the first paper in 1929 to the present day is given. The reaction is discussed from the view of the thermodynamics; the main catalysts studied for the reaction are summarised, and the reaction mechanism is discussed. The review is not comprehensive, but it is designed to provide a general background to the most important developments in the field.     

甲烷部分氧化制合成气的研究进展

综述了近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存在的主要问题。     

甲烷部分氧化制合成气催化剂的研究进展

综述了甲烷部分氧化制合成气的研究意义和现状，从金属活性组分，载体效应，载量选择，助剂添加和制备方法等因素对催化剂活性的影响及研究进行了系统。结合本课题组的研究结果及文献报道，分析了Ni基催化剂的失活特性，并提出使用等离子体技术对Ni基催化剂进行改笥处理，以提高其催化稳定性的技术展望。     

甲烷部分氧化制合成气催化剂的研究进展

甲烷部分氧化（POM）反应制合成气是化学利用甲烷的有效途径之一。研究表明,甲烷部分氧化反应的工艺有能耗低和反应速率较快等优点,而且所得的H2和CO的比例适于合成甲醇等工业化学品。在该工艺过程中,所需反应容器体积小,反应效率高,可大幅度降低制备合成气的成本。开发POM反应的高效催化剂是进一步提高反应效率、实现工业化的关键途径,因此,是当前国际催化领域研究的热门课题之一。本文主要介绍了传统的金属负载型催化剂和金属氧化物催化剂用于POM反应的研究进展。     

在助剂改性的Mo/SiO2催化剂上甲烷部分氧化合成甲醇

用L ₉(3⁴) 正交配置实验对2%Mo/SiO₂ 催化剂进行了改性研究, 发现Cr、Cu、Sn 和P 可改变催化剂的活性和选择性, 在Cr 为0.5% 时有较高的甲醇收率, 在450℃、常压下反应可使甲醇收率为2176%。XPS、FT -IR、TPR 和TPD 研究表明催化剂表面上的Mo 为+ 6 价, 且存在Mo-Si 作用键, 催化剂表面有大量的酸性中心和多种相互作用相。     

甲烷部分氧化制合成气镍基催化剂的研究进展

镍基催化剂是甲烷部分氧化制合成气研究最多、最有前途的催化剂.相对其他催化剂它具有较好的抗积碳性、稳定性且价格低廉.如何提高甲烷在部分氧化反应中的转化率是当前备受关注的重要研究课题.从镍基催化剂的载体、助剂、制备方法等方面的研究进行了综述.     

甲烷二氧化碳催化重整制取合成气的研究进展

近几十年来,甲烷二氧化碳催化重整反应引起了广泛的关注。综述了甲烷二氧化碳催化重整制取合成气的研究进展,介绍了催化剂的活性组分、载体、助催化剂及制备方法的研究现状和它们对催化剂活性和稳定性的影响情况,并对催化剂积炭的形成和消除、重整反应机理进行了讨论和分析。     

Oscillatory Behavior During the Partial Oxidation of Methane Over Nickel Foils

The study of the partial oxidation of methane over nickel foils has been carried out over a wide range of reactor temperatures (748-930 °C) and feed-gas compositions (Ar/CH₄/O₂), ranging from 30:29:1 to 30:12:18 cm³ min^-1 at atmospheric pressure. The product formation shows pronounced oscillations. A modified thermocouple was designed to measure the temperature while the interposed nickel foil worked as a catalyst. The oscillations have been attributed to the cyclic reduction and oxidation of the nickel surface in the specific reaction environment at elevated temperatures.     

Sonochemically Prepared high Dispersed Ru/TiO2 Mesoporous Catalyst for Partial Oxidation of Methane to Syngas

Highly dispersed Ru nanoparticles on mesoporous TiO₂ have been synthesized by a one-step ultrasound assisted polyol reduction procedure. The catalysts have been characterized by XRD, TEM and HR-TEM, EDX, BET and TPR methods. It has been demonstrated that the sonochemical method reduces the Ru⁺³ ions creating a narrow size distribution of metallic nanoparticles deposited on the mesoporous support without damaging its pore structure. The nanoparticles of Ru are highly dispersed and stable because of their incorporation into the mesopores, and the strong metal-support interaction. The catalytic properties of Ru/TiO₂(MSP) have been tested in the partial oxidation of methane, and high activity and selectivity towards CO and H₂ have been demonstrated.     

Partial Oxidation of Methane to Syngas in a Packed Bed Catalyst Membrane Reactor

The planar membrane reactor configuration was explored for partial oxidation of methane (POM) to syngas. A supported membrane composed of yttria‐stabilized zirconia and La_0.8Sr_0.2Cr_0.5Fe_0.5O_3‐δ was sealed to a stainless holder, and a Ni/Al₂O₃ catalyst bed was placed under the membrane plane with a small slit between them. This reactor configuration would facilitate the POM reaction via oxidation‐reforming mechanism: the oxidation reaction occurring at the membrane surface and the reforming reaction taking place in the catalyst bed. At 800°C and a methane feed rate of 32 mL min^?1, the reactor attained methane throughput conversion over 90%, CO and H₂ selectivity both over 95%, and an equivalent oxygen permeation rate 1.4 mL cm^?2 min^?1. The membrane and catalyst remained intact after the POM testing. The planar membrane reactor configuration explored in this study may lead to the development of a compact reactor for syngas production. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2170–2176, 2016     

Methane Oxidation Over M–8YSZ and M–CeO2/8YSZ (M = Ni, Cu, Co, Ag) Catalysts

The oxidation of methane has been studied by sequential flow reaction experiments over M–8YSZ and M–CeO₂/8YSZ (M=Ni, Cu, Co, Ag) catalysts as a function of CH₄/O₂ from 773 to 1073 K. Over Ni–8YSZ and Ni–CeO₂/8YSZ, methane pyrolysis is dominant leading to surface carbon formation at temperatures of 873 K and above. While the addition of ceria to Ni–8YSZ to produce Ni–CeO₂/8YSZ does not significantly affect the reaction kinetics, the activity of Cu–CeO₂/8YSZ, Co–CeO₂/8YSZ, and Ag–CeO₂/8YSZ are higher than their M–8YSZ counterparts. The activity of Co–CeO₂/8YSZ at high temperatures (973 K and above) is higher than Ni-8YSZ with selectivity towards partial methane oxidation and CO formation. Considering Ni-based catalysts are prone to deactivation due to surface carbon accumulation, Co–CeO₂/8YSZ, Cu–CeO₂/8YSZ, and Ag–CeO₂/8YSZ are possible alternative anode cermets for direct hydrocarbon oxidation solid-oxide fuel cells (SOFC).     

甲烷部分氧化制合成气反应的研究

用粒度为5mm的α－Al2O3、β-Al2O3、γ-Al2O3为载体，用浸渍法制备了10％（质量）Ni基催化剂。在固定床流动反应器中，在反应温度500－850℃，大空速和不同的CH4／O2摩尔比下，测定了该催化剂用于甲烷部分氧化制合成气的活性和CO选择性。500℃用H2对催化剂还2h后，进行活性测试结果,10%Ni／β-Al2O3、Ni／γ-Al2O3对POM反应无活性，只有10％Niα－Al2O3对POM反应有活性。TPR测试结果表明，这是由于10％Ni／β-Al2O3和Ni／γ-Al2O3催化剂在700℃以下未被还原所致。另外，合成气的生成速率和CO选择尾均随反应温度和空速的增大而增大，并在CH4／O2摩尔比2时有最大值。     

甲烷部分氧化反应的磷钨酸催化剂研究

以磷钨酸为催化剂和氧化剂,进行了无氧条件下的甲烷气固相部分氧化的实验研究,考察了磷钨酸催化剂的制备条件、载体影响以及反应温度对甲烷部分氧化反应的影响等.磷钨酸催化剂可有效催化甲烷部分氧化反应,甲烷首先转化生成醋酸甲酯,醋酸甲酯水解生成甲醇.制备的催化剂以SiO2为载体,采用载体质量15%(wt)的磷钨酸水溶液回流浸渍4 h、120℃干燥2 h、300℃焙烧4 h制得.甲烷部分氧化反应在0.10 MPa、267～280℃进行,甲烷转化率为26.61%,目的产物收率25.82%.     

Selective Oxidation of Methane to Syngas over NiO/Barium Hexaaluminate

The preparation, characterization and reactivity of NiO over barium hexaaluminate in the partial oxidation of methane is investigated. It is found that the prepared NiO supported catalysts are extremely active in the catalytic oxidation of methane, with 95% CH₄ conversion and 98% CO selectivity achieved at 850°C. Highly disperse nickel oxide interacting with the support clearly shows the efficient use of the active nickel phase. In particular, the special structure of the barium hexaaluminate prevents its lattice from being destroyed by Ni ions when the Ni loading is as high as 20 wt%. The layered aluminate type structure of the barium hexaaluminate support can accommodate Ni ions in the structure so that there exists interaction between Ni ions and support, which causes the supported catalysts to possess excellent stability and capability to suppress carbon deposition.     

甲烷部分催化氧化合成甲醇和甲醛

本文综述了由甲烷部分催化氧化制甲醇和甲醛研究中所用催化剂的制备条件及催化反应条件,并对用于该反应的催化剂开发和最佳合成工艺条件的选择指出了方向。     

甲烷催化部分氧化制合成气的研究进展

文章叙述了甲烷催化部分氧化制合成气研究的进展情况。介绍了两种主要的反应机理：间接反应机理和直接反应机理;对负载型镍系催化剂的研究现状进行了叙述,并简单介绍了非负载型催化剂;另外还对固定床、流化床、膜反应器以及一些新开发的反应器的特点进行了讨论。     

The Partial Oxidation of CH3OH to CO2 and H2 Over a Cu/ZnO/Al2O3 Catalyst

The partial oxidation of CH₃OH to CO₂ and H₂ over a Cu/ZnO/Al₂O₃ catalyst has been studied by temperature-programmed oxidation (TPO) using N₂O and O₂ as the oxidant. Post-reaction analysis of the adsorbate composition of the surface of the catalyst was determined by temperature-programmed desorption (TPD). The temperature dependence of the composition of the mixture of products formed by TPO was shown to depend critically on the partial pressure of the oxidant, with the highest partial pressure of oxygen used (10% O₂ in He, 101 kPa—the CH₃OH partial pressure was 17% throughout), producing marked non-Arrhenius fluctuations on temperature programming. Unsurprisingly, therefore, the adsorbate composition of the catalyst revealed by post-reaction TPD was also found to be determined by the partial pressure of the oxidant. Using high partial pressures of oxidant (5% and 10% O₂ in He, 101 kPa), the only adsorbate detected was the bidentate formate species adsorbed on Cu. Lowering the oxygen partial pressure to 2% in He (101 kPa) revealed a catalyst surface on which the bidentate formate on Cu was the dominant intermediate with the formate on Al₂O₃ also being present. A further lowering of the partial pressure of the oxidant, obtained by using N₂O as the oxidant (2% N₂O in He, 101 kPa), resulted in a surface on which the formate adsorbed on ZnO was the dominant adsorbate with only a small coverage of the Cu by the bidentate formate.     

Catalyst Design of Pt-Modified Ni/Al2O3 Catalyst with Flat Temperature Profile in Methane Reforming with CO2 and O2

Pt(0.3)/Ni(10)/Al₂O₃, prepared by a sequential impregnation method, exhibited a more excellent performance in methane reforming with CO₂ and O₂ in terms of the catalytic activity and the temperature profile of the catalyst bed than Pt(0.3) + Ni(10)/Al₂O₃ prepared by a coimpregnation method, Ni(10)/Al₂O₃, Pt(0.3)/Al₂O₃, and Pt(10)/Al₂O₃. It is thought that this is because the surface Pt atoms on Ni catalyst can contribute to the enhancement of the catalyst reducibility.     

Methane Conversion to Synthesis Gas by Partial Oxidation and CO2 Reforming over Supported Platinum Catalysts

Partial oxidation of methane and reforming of methane with CO₂ were carried out with Pt/Al₂O₃, PtZrO₂ and Pt/CeO₂ catalysts, in the temperature range of 350–900 °C. For partial oxidation, the catalysts showed similar stabilities, with the PtZr slightly more active. The reaction occurs in two simultaneous stages: total combustion of methane and reforming of the unconverted methane with steam and CO₂, with the O₂ conversion of 100% over the whole temperature range. For reforming with CO₂, the catalysts presented similar activities, but with distinct deactivation rates: while the PtAl deactivates very fast at 800 °C, due to deposition of inactive carbon, the PtZr and PtCe catalysts offer higher resistance to coke formation, due to the metal-support interactions and the higher mobility of oxygen in the oxide lattice.