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。     

CH4／CO2催化重整制合成气的研究进展

甲烷和二氧化碳反应催化重整制取合成气有效利用两种温室气体,对改善人类生存环境和缓解能源危机具有重要意义,近年来引起广泛研究者的关注。本文参阅了许多有关甲烷与二氧化碳催化重整制合成气的相关文献,概述了近年来在此研究中催化剂的选择、载体的作用、助剂的影响及催化剂积炭等方面的研究进展。     

二氧化碳重整甲烷制合成气研究进展

由于二氧化碳重整甲烷制合成气具有很多优点,因此引起了广泛的关注。本文综述了二氧化碳重整甲烷制取合成气的研究进展,介绍了二氧化碳重整甲烷热力学、甲烷和二氧化碳的活化、二氧化碳重整甲烷反应过程中的表面积碳和消碳和二氧化碳重整甲烷反应机理的研究现状,并进行了讨论和分析。     

甲烷二氧化碳催化重整制合成气研究进展

催化剂研究是实现甲烷二氧化碳重整制合成气工业化的关键。对近年来甲烷二氧化碳重整制合成气的催化剂研究进行综述。介绍了贵金属催化剂、非贵金属催化剂及碳化物催化剂在甲烷二氧化碳重整反应中的应用及反应机理,并对催化剂体系研究方向进行展望。     

甲烷二氧化碳催化重整制合成气的研究进展

甲烷、二氧化碳重整制合成气过程是近十几年来世界范围的研究热点之一。随着对该反应研究的不断深入,在催化剂的活性组分、载体及助剂等方面已经取得了一致性的意见,在仍存在争议的催化剂积炭失活及反应机理、速率控制步骤等方面还需进一步研究,寻找出更有效的方法。综述了甲烷二氧化碳催化重整制合成气的研究进展,介绍了催化剂的活性组分、载体、助剂及制备方法的研究现状,并对催化剂积炭过程和重整反应机理进行了讨论和分析。     

甲烷二氧化碳催化重整制合成气的研究进展和工艺技术

近几年随着我国科学技术和经济水平的不断发展和提升,随之而来的环境问题也日益严峻,而二氧化碳则是重要的一环,为此我国政府以及相关工作部门加强了对甲烷和二氧化碳催化重整制合成气的研究力度。在甲烷和二氧化碳催化重整的相关技术取得阶段成果的同时,在反应时涉及的难点部分:催化剂的活性组分、载体的研究以及助剂的研究取得了突破,这体现出对工业发展质量和速度的高度肯定,但重整过程中仍然存在催化剂积碳失活等问题。主要对重整过程进行了综述,对重整过程需要的催化剂活性组分、载体以及催化剂积碳行为进行了介绍,并对制备方法进行了讨论。     

天然气转化制备合成气研究进展

综述了目前转化利用天然气制备合成气的主要方法,包括甲烷水蒸气重整、甲烷部分氧化、甲烷二氧化碳重整、甲烷水蒸气重整与部分氧化耦合反应、甲烷部分氧化与二氧化碳重整耦合反应、甲烷水蒸气重整与二氧化碳重整耦合反应以及甲烷的三重整反应,重点介绍了前3种典型反应所用的催化剂,最后提出将这3种典型反应耦合使用,并辅以晶格氧工艺、等离子体技术、微波技术是未来甲烷转化制备合成气的发展趋势。     

甲烷与二氧化碳重整制合成气Ni与Co基催化剂的研究进展

综述了助剂、载体与催化剂制备方法对Ni基催化剂、Co基催化剂、Ni-Co基催化剂上甲烷与二氧化碳重整制合成气催化性能的影响,以及甲烷与二氧化碳重整催化反应机理的研究,展望了催化剂未来的发展方向。     

甲烷与二氧化碳重整制合成气Ni与Co基催化剂的研究进展

综述了助剂、载体与催化剂制备方法对Ni基催化剂、Co基催化剂、Ni-Co基催化剂上甲烷与二氧化碳重整制合成气催化性能的影响,以及甲烷与二氧化碳重整催化反应机理的研究,展望了催化剂未来的发展方向。     

甲烷和二氧化碳催化重整制合成气的研究进展

回顾合成气制备的向种途径；评述了甲烷二氧化碳催化重整制合成气的催化剂研究状况，并对催化剂炭和反应机理进行了简单的介绍。     

Power- and resource-saving process for producing methanol from natural gas

The processes for producing methanol from syngas and syngas from natural gas are simulated. A kinetic model for the reaction of steam-carbon dioxide reforming of methane that is in good agreement with the experimental data obtained for the ranges of gas hourly gas velocities of 1000 to 10000 h^?1, temperatures of 700 to 850°C, and pressures of 0.4 to 2.0 MPa is developed. A power-and resource-saving process flowsheet for the production of methanol at a variable pressure in the catalytic reactors is proposed. Methods of intensifying an industrial methanol synthesis process with an end-product output of 60000 tons per year are developed. It is shown that when the carbon dioxide formed in the reaction of steam reforming of methane is recycled to the feed, the methanol output can be increased up to 72000 tons per year.     

A novel process for converting coalmine-drained methane gas to syngas over nickel–magnesia solid solution catalysts

A novel process is developed in this paper for utilizing the coalmine-drained methane gas that is usually vented straight into the atmosphere in most coalmines worldwide. It is expected that low-cost syngas can be produced by the combined air partial oxidation and CO₂ reforming of methane, because this process utilizes directly the methane, air, and carbon dioxide in the coalmine-drained gas without going through the separation step. For this purpose, a nickel–magnesia solid solution catalyst was prepared and its catalytic performance for the proposed process was investigated. It was found that calcination temperature has significant influence on the catalytic performance due to the different extent of solid solution formation in the catalysts. A uniform nickel–magnesia solid solution catalyst exhibits higher stability than the catalysts in which NiO has not completely formed solid solution with MgO. Its catalytic activity and selectivity remain stable during 120 h of reaction. The product H₂/CO ratio is mainly dependent on the feed gas composition. By changing CO₂/air ratio of the feed gases, syngas with a H₂/CO ratio between 1 and 1.9 can be obtained. The influences of reaction temperature and nickel loading on the catalytic performance were also investigated.     

Catalytic activity of coal ash on steam methane reforming and water-gas shift reactions

The catalytic activity of Clarion 4A coal ash on water-gas shift, steam methane reforming and carbon dioxide methane reforming reactions was studied in an atmospheric fluidized bed over temperatures ranging from 370°C to 900°C. The rates of steam methane reforming and water-gas shift reactions over ash were found to be several times the corresponding non-catalytic reactions but were one order of magnitude lower than the reactions over commercial catalysts. Also, it was found that the ash affected the water-gas shift reaction more significantly than the steam methane reforming reaction probably because of the larger amount of iron oxide in the coal ash. However, there was no appreciable reaction for carbon dioxide reforming up to 900°C.     

甲烷水蒸汽催化转化的动力学模型

在常压下使用内循环式无梯度反应器研究了Z102镍催化剂上甲烷水蒸汽催化转化反应的动力学。实验条件如下:反应温度500—700℃,H_2O/CH_4=2.5—4.5（克分子比）,甲烷空速为2000—10000ml/h·g-cat。根据实验结果的分析,作者认为在反应过程中一氧化碳和二氧化碳是同时生成的,即甲烷水蒸汽催化转化反应可用平行反应模型来表示。所得到的一氧化碳及二氧化碳的生成速度方程分别为: rco=k,p_(CH_4)~(0.8)及 rco_2=k_2p_(CH_4)~(0.8) p_(H_2O)~(1.5)反应速度常数k_1及k_2与温度的关系均符合阿累尼乌斯方程。一些研究者认为在通常的操作条件下,甲烷水蒸汽催化转化反应过程中,水煤气变换反应很快就达到平衡,我们的实验数据计算证明这个见解是不妥的。     

热等离子体重整二氧化碳和甲烷制合成气的研究进展

合成气是一种非常重要的化工原料,近年来利用甲烷和二氧化碳重整制合成气成为了一个研究热点。本文讨论了等离子体重整的机理,重点介绍了不同重整方式,包括射流法、电弧法以及两者结合的方法在二氧化碳和甲烷重整中的应用。相对于冷等离子体,热等离子体重整更适合应用于工业放大生产,有较好的应用前景。     

Bench- and Pilot-Scale Studies of Reaction and Regeneration of Ni–Mg–K/Al2O3 for Catalytic Conditioning of Biomass-Derived Syngas

The National Renewable Energy Laboratory (NREL) is collaborating with both industrial and academic partners to develop technologies to help enable commercialization of biofuels produced from lignocellulosic biomass feedstocks. The focus of this paper is to report how various operating processes, utilized in-house and by collaborators, influence the catalytic activity during conditioning of biomass-derived syngas. Efficient cleaning and conditioning of biomass-derived syngas for use in fuel synthesis continues to be a significant technical barrier to commercialization. Multifunctional, fluidizable catalysts are being developed to reform undesired tars and light hydrocarbons, especially methane, to additional syngas, which can improve utilization of biomass carbon. This approach also eliminates both the need for downstream methane reforming and the production of an aqueous waste stream from tar scrubbing. This work was conducted with NiMgK/Al₂O₃ catalysts. These catalysts were assessed for methane reforming performance in (i) fixed-bed, bench-scale tests with model syngas simulating that produced by oak gasification, and in pilot-scale, (ii) fluidized tests with actual oak-derived syngas, and (iii) recirculating/regenerating tests using model syngas. Bench-scale tests showed that the catalyst could be completely regenerated over several reforming reaction cycles. Pilot-scale tests using raw syngas showed that the catalyst lost activity from cycle to cycle when it was regenerated, though it was shown that bench-scale regeneration by steam oxidation and H₂ reduction did not cause this deactivation. Characterization by TPR indicates that the loss of a low temperature nickel oxide reduction feature is related to the catalyst deactivation, which is ascribed to nickel being incorporated into a spinel nickel aluminate that is not reduced with the given activation protocol. Results for 100?h time-on-stream using a recirculating/regenerating reactor suggest that this type of process could be employed to keep a high level of steady-state reforming activity, without permanent deactivation of the catalyst. Additionally, the differences in catalyst performance using a simulated and real, biomass-derived syngas stream indicate that there are components present in the real stream that are not adequately modeled in the syngas stream. Heavy tars and polycyclic aromatics are known to be present in real syngas, and the use of benzene and naphthalene as surrogates may be insufficient. In addition, some inorganics found in biomass, which become concentrated in the ash following biomass gasification, may be transported to the reforming reactor where they can interact with catalysts. Therefore, in order to gain more representative results for how a catalyst would perform on an industrially-relevant scale, with real contaminants, appropriate small-scale biomass solids feeders or slip-streams of real process gas should be employed.     

Tri-reforming of CH4 using CO2 for production of synthesis gas to dimethyl ether

In general, there are three processes for production of synthesis gas; steam reforming, CO₂ reforming and partial oxidation of methane or natural gas. In the present work, we refer to tri-reforming of methane to synthesize syngas with desirable H₂/CO ratios by simultaneous oxy-CO₂-steam reforming of methane. In this study, we report the results obtained on tri-reforming of methane over the Ni/ZrO₂ based catalyst in order to restrain the carbon deposition and to evaluate the catalytic performance. Results of tri-reforming of CH₄ by three catalysts (Ni/Ce–ZrO₂, Ni/ZrO₂ and Haldor Topsoe R67-7H) are showed that the coke on the reactor wall and the surface of catalyst were reduced dramatically. It was found that the weak acidic site, basic site and redox ability of Ce–ZrO₂ play an important role in tri-reforming of methane conversion. Carbon deposition depends not only on the nature of support, but also on the oxidant as like steam or oxygen. Therefore, the process optimization by reactant ratios is important to manufacture the synthesis gas from natural gas and carbon dioxide.