STUDIES ON REFORMING NATURAL GAS WITH CARBON DIOXIDE TO PREPARE SYNTHESIS GAS

采用固定床流动反应器和ＸＲＤ、ＴＰＲ等技术对添加了Ｌａ２Ｏ３助剂的Ｎｉ／αＡｌ２Ｏ３催化剂进行了研究。结果表明，经Ｌａ２Ｏ３改性后，催化剂的活性和稳定性得到提高，Ｌａ２Ｏ３的最佳含量为２％（ｗｔ）。脉冲试验结果表明，添加２％（ｗｔ）的Ｌａ２Ｏ３助剂，能够有效抑制甲烷脱氢性能，增加二氧化碳消碳活性。ＴＰＲ结果表明，添加Ｌａ２Ｏ３助剂，能够改变活性组分和载体之间的相互作用，增加镍的分散度，降低氧化镍的还原温度，提高重整反应的活性。     

甲烷干气重整反应进展(英文)

系统地回顾和总结了二氧化碳重整反应的研究进展和现状,包括催化剂活性组分、载体、助剂以及催化剂制各方法等因素对催化剂性能的影响,同时对催化剂活性组分与反应中间体的结构与性能、反应机理和动力学行为及催化剂失活特性进行了细致的分析。大量研究表明金属镍是最富潜力的干气重整催化剂活性组分,而催化剂积炭是决定该反应能否工业化的关键因素。探索抑制催化剂积碳失活的有效途径是二氧化碳重整过程开发成功的关键。甲烷二氧化碳（干气）重整反应的研究和开发将提供一条天然气有效利用与温室气体减排的有效途径。     

甲烷催化二氧化碳重整制合成气反应研究进展*

本文参阅了甲烷催化二氧化碳重整制合成气反应研究方面50 余篇文献, 概述了近年来在该研究中催化剂活性组分选择、载体效应、助剂的作用、催化剂积炭行为和重整反应机理等方面的研究进展。     

天然气二氧化碳转化制合成气的研究──催化剂抗积炭性能(英文)

采用脉冲色谱技术、ＸＲＤ、ＴＰＲ和ＸＰＳ等方法研究了在天然气二氧化碳转化制合成气反应中催化剂的抗积炭性能。实验结果表明,在Ｎ　Ａｌ２Ｏ３催化剂中添加ＣｅＯ２和ＭｇＯ助剂（催化剂记为Ｎｉ／ＡＲＭ）能有效抑制甲烷脱氢反应,提高二氧化碳消炭能力,增加催化剂的抗积炭性能。其主要原因是,添加ＣｅＯ２和ＭｇＯ助剂增加了活性组分镍的分散度,加强了活性组分和载体的相互作用。改性后的Ｎｉ／ＡＲＭ催化剂在１０２３Ｋ、二氧化碳／天然气／氧气比为２．４／０．１以及１１２３Ｋ、二氧化碳／天然气／氧气比为１．４／１／０．０５的条件下反应８００小时后活性不降低,产物中合成气（ＣＯ＋Ｈ２）摩尔百分含量始终保持在９４－９６％左右。说明该催化剂具有较高的活性、选择性和抗积炭性。     

甲烷与二氧化碳重整制取合成气反应的研究：ⅢSr（La）NiAl11O19积炭动力学

用热重（ＴＧＡ）方法，研究了ＬａＮｉＡｌ１１Ｏ１９和ＳｒＮｉ１１Ｏ１９催化剂上甲烷与二氧化碳重整反应的积炭动力学。实验结果表明，甲烷裂解是ＣＨ４＋ＣＯ２反应中主要的积炭反应，甲烷的二氧化碳重整反应的积炭速率随反应温度升高而增大，但春衰减速度也较快；ＣＨ４＋ＣＯ２反应的积炭速率相对甲烷分压的反应级数是１，相对二氧化碳分压的反应级数是一－０５；在ＳｒＮｉＡｌ１１Ｏ１９中掺入Ｌａ＾３＋离子，提高了催化剂     

K-La-Ni/Si-2催化低碳烷烃与二氧化碳重整制合成气(英文)

Ｎｉ／Ｓｉ２催化剂具有较好的低碳烷烃与二氧化碳重整制合成气的反应性能，添加Ｌａ２Ｏ３助剂和Ｋ２Ｏ助剂可提高催化剂活性和合成气收率，从而进一步改善催化剂的低碳烷烃与ＣＯ２重整制合成气的反应性能，研制的ＫＬａＮｉ／Ｓｉ２催化剂，用于天然气与ＣＯ２重整反应制合成气可达９７％的低碳烷烃转化率和９５％以上的合成气收率。     

甲烷在Ni/TiO_2催化剂表面的活化

考察了Ｎｉ／ＴｉＯ２催化剂甲烷部分氧化和二氧化碳重整制合成气的反应活性,实验表明,以ＴｉＯ２为载体的镍系催化剂对于甲烷部分氧化制合成气反应具有较好的活性,尤其对Ｈ２的选择性较高,对二氧化碳重整制合成气反应具有较好的低温反应活性．采用脉冲－质谱在线分析等技术,在无气相氧条件下向Ｎｉ／ＴｉＯ２催化剂脉冲ＣＨ４,发现甲烷在催化剂表面的活化（转化）及其氧化产物的选择性与金属催化剂表面氧的浓度密切相关．ＣＨ４与Ｎｉ／ＴｉＯ２催化剂作用过程中存在明显的氢溢流和氧溢流现象,可能是这种溢流效应使得Ｎ／ＴｉＯ２催化剂具有良好的反应活性和抗积碳性能．     

Ni／γ—Al2O3,Ni／MgO,Ni／SiO2催化剂上甲烷与二氧化碳重整反应的研究

采用ＸＲＤ，ＵＶ－ＤＲＳ，ＸＰＳ，ＴＰＲ，Ｈ２－Ｏ２滴定和吡啶吸附－红外光谱等技术，研究了负载于具有不同酸碱性的γ－Ａｌ２Ｏ３，ＳｉＯ２，Ｍｇｏ载体上的镍催化剂表面物理化学性质，及其对甲烷与二氧化碳重整制取合成气反应催化活性的影响。结果表明，在上述负载型镍催化剂上，影响重整反应活性和积炭量的主要原因不是催化剂表面酸碱性，而是金属镍在催化剂表面的分散度。     

La2O3—Ni／SrAl12O19催化剂上甲烷与二氧化碳重整反应的研究

采用ＸＲＤ，ＵＶ－ＤＲＳ，Ｈ２－Ｏ２滴定，ＴＰＲ，吡啶吸附红外光谱等技术，研究了Ｌａ２Ｏ３助剂对Ｌａ２Ｏ３－Ｎｉ／ＳｒＡｌ１２Ｏ１９催化剂的还原性，表面酸性，金属镍的分散度和抗烧结能力，以及对催化甲烷与二氧化碳重整制取合成气反应性能的影响。结果表明，在负载型的镍催化剂中，添加Ｌａ２Ｏ３助剂，能够削弱金属组分与载体之间的相互作用，降低催化剂的还原性，提高金属镍在催化剂表面的分散度和在反应过程中的抗烧     

MoO＿3／（TiO＿2－SiO＿2）催化剂的表面分散状态及催化性能的研究

用气相流动吸附法（ｇｒａｆｔｉｎｇ）制备复合载体，用浸渍法（ｉｍｐｒｅｇｎａｔｉｏｎ）制备ＭｏＯ３／（ＴｉＯ２－ＳｉＯ２）催化剂．应用ＬＲＳ和ＴＰＲ技术研究ＭｏＯ３在复合载体ＴｉＯ２－ＳｉＯ２表面的分散状态，发现ＴｉＯ２在ＳｉＯ２表面的分散可增强ＭｏＯ３与载体之间的相互作用，提高ＭｏＯ３在载体表面的分散阈值．催化剂的活性评价在固定床中压反应装置中进行，以６９％（ｗｔ）环己烷、２０％（ｗｔ）的环己烯、１０％（ｗｔ）的苯、１％（ｗｔ）的噻吩混合液为反应液，以噻吩、环己烯和苯的转化率作为催化剂的ＨＤＳ、ＨＹＤ、ＢＨＤ活性指标．结果表明，经ＴｉＯ２调变后，其ＨＤＳ、ＨＹＤ、ＢＨＤ活性都较原来高，对于不同ＭｏＯ３含量的ＭｏＯ３／（ＴｉＯ２－ＳｉＯ２），ＨＤＳ、ＨＹＤ催化性能测试发现，当ＭｏＯ３含量低于分散阈值时，其ＨＤＳ、ＨＹＤ活性随ＭｏＯ３含量线性上升，但在高于分散阈值后，几乎保持不变．该催化剂对苯几乎没有加氢活性，显示出很高的环己烯加氢选择性．通过分散阈值与其ＨＤＳ、ＨＹＤ活性的关系可知，分散阈值可作为优化加氢精制催化剂配比的一个重要参数，具有较强的实际意义     

STUDIES OF THE HOMOLOGATION OF METHANE ONSUPPORTED TRANSITION METAL CATALYSTS

Introduction0ncofthcintriguingpr0blcmsinhctcrogcncouscatal}'sisisthcactit'ationanddircctconversionofmcthancintoliquidfucIanduscful.h..i..l,lllMcthancactivationisvcry'difficultbccauscn1cthancisathcrmod}'namicalI}'stablccompoundt`ithanoblcgas-likcconfigurati0nThcvcry'strongtctrahcdralC-Hbonds(435kJ/mol)offcrnofiJnctionalgroups,magncticm0mcnts'orpolardistortionstofacilitatcchcmicalattackThismakcsmcthanelcssrcactivcthanncarl}'allitsconvcrsionproducts.Rccentl}'oxidativccouplinghasbecnconsidcrcda…     

担载型过渡金属催化剂上甲烷同系聚合反应的研究

本文利用瞬变应答反应技术较系统地考察了担载型过渡金属催化剂上甲烷同系聚合制C2以上烃的反应, 研究发现通过采用总反应分解法操作, 可以克服甲烷同系聚合反应的热力学限制, 使该反应能在较为温和的条件下得以进行。本文还系统地探讨了影响该反应的各种因素。523K 5wt% Pt/SiO2上甲烷的最佳转化可达9,91%。Pt, Co催化剂表现出较为优越的催化性能。甲烷在催化剂表面分解产生的CHx(ad)(0<=x<=3)物种可能是该反应的活性中间体。     

Enhanced methane decomposition over transition metal-based tri-metallic catalysts for the production of COx free hydrogen

In this study, COx-free hydrogen production via methane decomposition was studied over Cu–Zn-promoted tri-metallic Ni–Co–Al catalysts. The catalysts have been prepared by the constant pH co-precipitation method, and the nominal Ni metal loading was fixed at 50 wt % along with other metals at 10 wt% each. The catalyst activity for methane decomposition reaction was examined in a reactor between 400 °C and 700 °C and at atmospheric pressure. Different techniques such as N₂-physisorption, X-ray diffraction, H₂-TPR SEM, TEM, ICP-MS, TGA, and Raman spectroscopy were applied to characterize the catalysts. The relation between the catalyst composition and their catalytic activity has been investigated. The controlled synthesis has resulted in a series of catalysts with a high surface area. Ni–Co–Cu–Zn–Al was the most active and productive catalyst. Various characterizations indicate that the promotional effects of Cu–Zn interaction were the critical factor in catalysts' activity and stability. Ni–Co–Cu–Zn catalyst gave the highest methane conversion of 85% at 700 °C. Zn addition improves the stability of the catalyst by retaining the active metal size during the decomposition reaction. The catalyst was active for 80 h of stability study. The rapid deactivation of the Ni–Co catalyst was due to the sintering of the catalyst at 650 °C. Moreover, carbon species accumulated during the methane decomposition reaction depend on the catalysts' composition. Zn promotes the growth of reasonably long and thin carbon nanotubes, whereas the diameter of carbon nanotubes on unpromoted catalysts was large.     

Syngas production by combined carbon dioxide reforming and partial oxidation of methane over Ni/α-Al2O3 catalysts

Ni/α-Al2O3 catalysts were found to be active in the temperature range 600~900 ℃ for both CO2 reforming and partial oxidation of methane. The effects of Ni loading, reaction temperature and feed gas ratio for the combination of CO2 reforming and partial oxidation of CH4 over Ni/α-Al2O3 were investigated. Catalysts of xwt%Ni/α-Al2O3 (x = 2.5, 5, 8 and 12) were prepared by wet impregnating the calcined support with a solution of nickel nitrate. XRD patterns and activity tests have verified that the 5wt%Ni/α-Al2O3 was the most active catalyst, as compared with the other prepared catalyst samples. An increase of the Ni loading to more than 5 wt% led to a reduction in the Ni dispersion. In addition, by combining the endothermic carbon dioxide reforming reaction with the exothermic partial oxidation reaction, the loss of catalyst activity with time on stream was reduced with the amount of oxygen added to the feed.     

PROMOTING EFFECT OF RARE EARTH OXIDES ON Ni/Re_xO_y-Al_2O_3 CATALYST FOR PARTIAL OXIDATION OF METHANE TO SYNTHESIS GAS

IntroductionSynthesisgas(HZ CO)isproducedfrommethanemoshybysteamrefonningwhichsuffersfromlimitationssuchasveryhighenergyrequirements,complicatedequipmentandinstallations,highHZ/COproductratioandpoorselectivityforcarbonmonoxide.Recently,manyresearchershave…     

Ni/Al2O3催化甲烷裂解

分别通过浸渍法和共沉淀法制备了不同Ni负载量的Ni/Al2O3催化剂。考察了Ni负载量、制备方法以及反应温度对Ni/Al2O3催化甲烷裂解性能的影响。结果表明,在550℃,浸渍法制备的Ni/Al2O3催化剂,当Ni负载量为20%(质量分数)、Ni金属平均粒径为11.25 nm时,具有最佳的甲烷催化裂解效果,其每摩尔Ni的氢气产量和每克Ni碳产量分别为164 mol和15.30 g。催化剂制备方法对Ni/Al2O3甲烷催化裂解反应有显著影响,相同Ni负载量共沉淀法制备的Ni/Al2O3甲烷催化裂解总体效果要好于浸渍法制备的Ni/Al2O3,而且反应过程中生成的碳纤维较长,管径也较均一。550℃时,共沉淀法制备的Ni负载量为41.2%(质量分数)的Ni/Al2O3催化剂在反应至350 min时,仍保持着30%以上的转化率。     

Ni/Al2O3催化剂上甲烷部分氧化制合成气反应机理

用变应答／质谱在线检测技术研究了Ｎｉ／Ａｌ２Ｏ３催化剂上甲烷部分氧化制合成气的反应要理，研究结果指出，在常压９７３Ｋ条件下，Ｎｉ／Ａｌ２Ｏ３催化剂上甲烷部分氧化制合成气按直接氧化机理进行，Ｈ２和Ｃ烛甲烷部分氧化的一次产物，其主要反应可表示如下：１．ＣＨ４＋ｘＮｉ－ＮｉｘＣ＋２Ｈ２，２．Ｏ２＋２Ｎｉ－２ＮｉＯ，３．ＮｉｘＣ＋ＮｉＯ－ＣＯ＋（ｘ＋１）Ｎｉ。     

新型纳米介孔二氧化锆担载的镍基催化剂甲烷干气重整性能评价

采用固体反应．模板剂晶化法合成出纳米介孔二氧化锆，并以其为载体通过浸渍法制备了Ni基催化剂，考察了载体性质对催化剂活性和稳定性的影响．结果表明，以四方晶相纳米二氧化锆为载体的催化剂性能更佳，并对其影响因素进行了分析．     

Effect of MgO promoter on Ni-based SBA-15 catalysts for combined steam and carbon dioxide reforming of methane

A series of Ni/SBA-15 catalysts with Ni contents ranging from 5 wt% to 15 wt%, as well as another series of 10%Ni/MgO/SBA-15 catalysts, in which the range of the MgO content was from 1 wt% to 7 wt%, were prepared, and their catalytic performances for the reaction of combined steam and carbon dioxide reforming of methane were investigated in a continuous flow microreactor. The structures of the catalysts were characterized using the XRD, H2-TPR and CO2-TPD techniques. The results indicated that the CO selectivity for this reaction was very close to 100%, and the H2/CO ratio of the product gas could be controlled by changing the H2O/CO2 molar ratio of the feed gas. The simultaneous and plentiful existing of steam and CO2 had a significant influence on the catalytic performance of the 10%Ni/SBA-15 catalyst without modification. After reacting at 850 °C for 120 h over this catalyst, the CH4 conversion dropped from 98% to 85%, and the CO2 conversion decreased from 86% to 53%. However, the 10%Ni/3%MgO/SBA-15 catalyst exhibited a much better catalytic performance, and after reacting for 620 h, the CO2 conversion over this catalyst dropped from 92% to around 77%, while the CH4 conversion was not decreased. Oxidation of the Ni0 species as well as carbon deposition during the reaction were the main reasons for the deactivation of the catalyst without modification. On the other hand, modification by the MgO promoter improved the dispersion of the Ni0 species, and enhanced the CO2 adsorption affinity which in turn depressed the occurring of carbon deposition, and thus retarded the deactivation process.