整体式甲烷燃烧催化剂的活性研究

研究了以Co、Cr、Mn、Fe和Ni的单一或混合氧化物为活性组分的整体式催化剂在甲烷燃烧反应中的活性。整体式催化剂直径为 10mm ,长 15mm ,测试温度范围为 30 0 - 70 0℃。结果显示 ,单一氧化物中Co、Cr和Mn的活性较好 ,Fe和Ni的活性较差 ;混合氧化物催化剂均表现出较高的活性 ,但以含Co、Cr、Mn的 3组分混合氧化物催化剂为更佳。同时考察了空速、烷氧比、稀释气、温度等因素对甲烷燃烧反应的影响。在烷氧比为 1:4,稀释气含量约为 6 0 % ,反应温度 6 5 0℃ ,大空速下甲烷转化率较高。     

整体型海绵镍催化剂催化甲烷部分氧化制合成气

利用电沉积法制得的海绵镍制备了整体型海绵镍催化剂,并将其应用于甲烷部分氧化制合成气反应。考察了原料气配比、反应温度、空速、催化剂床层高径比等工艺条件对整体型海绵镍催化剂催化甲烷部分氧化制合成气反应的影响,并对催化剂进行了扫描电镜(SEM)和X射线衍射(XRD)表征。根据研究结果确定优化的工艺条件为:反应温度950℃,空速1.35×105h-1,原料气配比n(CH4)∶n(O2)=1.5,催化剂床层高径比0.75。在此工艺条件下的反应结果:CH转化率约90%,H选择性约80%,CO选择性约90%。     

Catalytic Materials Based on Hydrotalcite-Like Aluminum,Magnesium, Nickel,and Cobalt Hydroxides for Partial Oxidation and Dry Reforming of Methane to Synthesis Gas

Partial oxidation of methane and dry methane reforming to synthesis gas in the presence of catalysts based on hydrotalcite-like hydroxo salts [AlMg₂Ni _x Co _y (OH)_6.08][(NO₃) _n H₂O], where x = 0, 0.02, 0.04 and y = 0, 0.02, 0.04 with a total Ni and/or Co content of no more than 2 wt % have been first studied. It has been shown that the Ni-containing catalysts provide a synthesis gas yield of 90 and 97% in the case of partial oxidation and dry reforming of methane, respectively; in the presence of these catalysts, a trace amount of carbon nanotubes is formed; the catalyst sample containing both nickel and cobalt does not lead to the formation of any carbon nanotubes during dry reforming of methane.     

合成气完全甲烷化催化剂研究

制备了一系列金属镍催化剂并对其用于合成气完全甲烷化的催化活性进行了研究,结果表明:当NiO担载量在20%以上可以保证催化剂在高温高空速条件下具有很好的活性。Al2O3担载型镍催化剂引入金属Mg、La有利于提高催化剂的活性和稳定性。担载型NiOLa2O3MgO/Al2O3催化剂(wNiO=24%),装填两段反应器,经过两段反应后,CO平均转化率为99.97%,H2平均转化率99.83%,CH4平均选择性为98.44%。催化剂连续运行1000h性能稳定。     

Selective oxidation of methane into synthesis gas at short contact times on low-loading platinum-ruthenium catalysts

The results of the study of Pt-Ru/2% Ce/(θ + α)-Al₂O₃ catalysts with various Pt/Ru ratios used in the process of selective methane oxidation into synthesis gas at short contact times are presented. The optimal catalyst preparation conditions have been found for the process. It has been revealed that the methane conversion at 1173 K and a contact time of 4.0-3.0 ms varies from 96 to 100% and the selectivities for hydrogen and CO are 100 and 95–100%, respectively. At a Pt: Ru molar ratio of 2: 1 or 1: 1 and τ = 3.5 ms, the maximum (100%) degree of the conversion of methane into synthesis gas via the direct route is observed; the selectivity for H₂ and CO is 100%, and the total content of the noble metals is O ≥ 0.2%.     

锂和镧的添加对NiO/Al_2O_3甲烷部分氧化积炭的影响

采用ＮＨ３－ＴＰＤ技术考察了ＮｉＯ／Ａｌ２Ｏ３表面酸性，发现Ｌｉ和Ｌａ的添加使催化剂的表面酸性强度和酸性中心数目低于相应的ＮｉＯ／Ａｌ２Ｏ３。同时利用ＴＧ、ＴＰＯ－ＭＳ、ＸＰＳ等技术考察了ＮｉＯ／Ａｌ２Ｏ３和ＬｉＮｉＬａＯ／Ａｌ２Ｏ３上的甲烷部分氧化制合成气积炭情况。发现Ｌｉ和Ｌａ的添加显著提高了催化剂的抗积炭能力。ＬｉＮｉＬａＯ／Ａｌ２Ｏ３上甲烷部分氧化反应寿命实验表明，反应连续进行２００ｈ，ＣＨ４转化率一直保持不变，这说明Ｌｉ和Ｌａ的添加还可以提高ＮｉＯ／Ａｌ２Ｏ３的热稳定性。     

The mechanism of carbon dioxide hydrogenation on copper and nickel catalysts

The mechanism of the reaction of CO₂ with H₂ on copper and nickel catalysts was studied by means of isotope, non-steady-state, and steady-state methods. Staged schemes of the process were proposed. The slow step of CO formation on the test catalysts is the reaction of the adsorbed carboxylate complex with a hydrogen atom. It was shown that hydrogen adsorption on the copper catalyst is dissociative in character. A formyl complex and hydrogen are involved in the slow step of methane formation on the nickel catalyst. It was found that the methane formation proceeds via a consecutive scheme through CO.     

甲烷部分氧化制合成气的研究——不同Ni担载量催化剂的反应活性考察

在微型固定床反应器中,考察了不同担载量的镍系催化剂对甲烷部分氧化制合成气的催化反应行为的影响。结果表明：ｗ（Ｎｉ） ＝ ５ ％ 催化剂上的甲烷部分氧化的活性和ＣＯ 选择性最佳,在８２０ ℃时,该体系能获得９１－３ ％ 的ＣＨ４ 转化率,９７－２ ％ 的ＣＯ 选择性。在实验温度７５０ ～８７０ ℃内,随着反应温度的升高,该催化剂上的催化活性和ＣＯ 选择性均增加。在８７０ ℃时,ＣＨ４ 转化率为９４－３ ％ ,ＣＯ 选择性为９７－６ ％ 。用ＴＰＲ、ＸＲＤ 表征该系列催化剂的物化特性,将ＴＰＲ 和ＸＲＤ 的表征结果（ ｗ（Ｎｉ） ＝ ５ ％ 的催化剂没有ＮｉＯ 晶相,而 ｗ（Ｎｉ） ＝ ８ ％ ～１８ ％ 的催化剂有该晶相） 及反应温度与Ｎｉ 担载量进行关联,可解释反应结果。     

甲烷－CO_2制取合成气研究现状评述

介绍和评述了国内外对甲烷－ＣＯ２转化反应制取合成气的动态。其中包括充分利用甲烷和ＣＯ２的意义、转化反应的研究历史、体系动力学研究、反应机理、催化剂的选择、镍催化剂积炭失活以及助剂的影响等。指出了该研究的发展趋势。     

甲烷－CO_2制取合成气研究现状评述

介绍和评述了国内外对甲烷－ＣＯ２转化反应制取合成气的动态。其中包括充分利用甲烷和ＣＯ２的意义、转化反应的研究历史、体系动力学研究、反应机理、催化剂的选择、镍催化剂积炭失活以及助剂的影响等。指出了该研究的发展趋势。     

Partial oxidation of methane to synthesis gas: Novel catalysts based on neodymium–calcium cobaltate–nickelate complex oxides

Novel catalysts based on neodymium–calcium cobaltate–nickelate complex oxides for the partial oxidation of methane to synthesis gas have been synthesized and studied using catalyst precursors with the general formula NdCaCo_1–xNi _x O _n (x = 0, 0.2, 0.4, 0.6, 0.8, 1) prepared by the solid state synthesis method. It has been shown that the synthesized samples form a series of solid solutions with a K₂NiF₄ structure at x ≤ 0.8 or a rhombically distorted K₂NiF₄ structure at x = 1. The products of conversion of the resulting precursors in a methane–oxygen mixture at high temperatures have shown high methane conversions and synthesis gas yields. The highest values of these parameters have been achieved in the presence of catalysts synthesized by the reduction of NdCaCo_0.4Ni_0.6O _n and NdCaNiO _n precursors. The complete replacement of cobalt with nickel has led to an increase in the synthesis gas yield; however, it has been found that the resulting catalyst is prone to carbonization. It has been determined that an optimum nickel to cobalt ratio in the catalyst composition provides the formation of a carbonization-resistant catalyst.     

粉末模压法制备甲烷部分氧化制合成气反应镍金属催化剂

普通的负载型镍基催化剂,在甲烷部分氧化制合成气反应条件下,存在活性组分易烧结、易流失等缺陷。本文采用粉末模压法制备金属镍催化剂,并研究了催化剂的制备条件及其影响因素。制备的催化剂体现了良好的催化活性,在原料气配比n(CH4)/n(O2)=2.0、反应温度950℃、空速1.4×105h-1时,CH4转化率为89.64%、O2几乎完全反应,H2和CO选择性分别为82.71%和88.90%。     

Methane conversion to valuable chemicals over nanostructured Mo/ZSM-5 catalysts

Results of the ongoing study of nonoxidative methane dehydroaromatization (DHA) over Mo/ZSM-5 catalysts have been analyzed. The effects of the composition, preparation procedure, pretreatment, and the CH₄ DHA reaction conditions on the physicochemical and catalytic properties of Mo/ZSM-5 catalysts have been discussed. The data on Mo-containing active sites, the methane DHA reaction mechanism, and the nature of carbonaceous deposits have been considered. The principal causes of the deactivation of Mo/ZSM-5 catalysts and means of their regeneration have been revealed. Approaches to the improvement of the methane DHA process and trends of its further development have been detailed.     

甲烷部分氧化制甲醛──不同种类含硅化合物催化剂的研究

用纯氧作氧化剂，研究了甲烷在各种含硅化合物催化剂上的直接氧化反应。结果表明，不同的含硅化合物对部分氧化产物甲醛有不同的活性，在最佳条件下，用１号催化剂，ＣＨ２Ｏ产率最高可达２．１４％（４９．７２ｇ／ｍ３．ｈ）。对各种含硅化合物催化剂的红外和热重分析发现，不同催化剂上所含─ＯＨ量不同，这可能是催化剂活性差异的原因。     

Synthesis Gas Production by Partial Oxidation of Methane and Dry Reforming of Methane in the Presence of Novel Ni–Co/MFI Catalysts

Catalysts based on Ni, Co, and NiCo supported on MFI zeolites for the partial oxidation of methane and dry reforming of methane to synthesis gas have been synthesized and studied. The total metal content in the catalysts is 2 wt %. A commercial zeolite with a binder (alumina) and a binder-free zeolite synthesized by an accelerated microwave-assisted hydrothermal method are used as supports. The synthesis gas yield is 97% in the presence of Ni and NiCo catalysts supported on the MFI zeolite synthesized by the microwaveassisted hydrothermal method. The simultaneous presence of Ni and Co in the catalyst makes the sample resistant to coking during dry reforming of methane, whereas the Ni catalyst is characterized by the formation of a significant amount of carbon fibers.     

Selective Hydrogenation of Maleic Anhydride to Succinic Anhydride Over Nickel-palladium Catalysts

Hydrogenation of maleic anhydride (MA) to succinic anhydride (SA) over Ni-Pd bimetallic catalysts prepared by impregnation method has been studied at different Pd contents, pressures and temperatures. Catalytic activity was greatly influenced by the Pd content, pressure and temperature. Use of 5wt%Ni-0.02wt%Pd/clay catalyst, the 100% conversion for MA and 100% selectivity for SA were obtained for MA hydrogenation at normal pressure. The catalysts were characterized by an array of techniques, including X-ray diffraction (XRD) and H₂ temperature-programmed reduction (TPR). XRD and TPR studies showed that nickel was present as Ni²⁺ species on the support, and that there was no elemental nickel (Ni⁰) and Ni₂O₃ in the unreduced samples. XRD and TPR also showed that Pd was as amorphous existence on the catalysts.     

担载型过渡金属催化剂上CH_4+CO生成CH_3CHO反应的初步研究

利用程序升温脉冲反应、恒温脉冲反应及探针分子的表面反应技术,较系统地考察了担载型过渡金属催化剂上甲烷直接羰基化制乙醛的反应.研究发现,通过采用总反应分解法操作,即首先使甲烷在过渡金属表面分解.然后引入CO使其与甲烷分解产生的表面碳物种反应,实现甲烷的直接羰基化.这种操作能够克服甲烷直接羰基化反应的热力学限制,将总反应转化为两个可在较温和条件下发生的反应,首次实现了CH_4 +CO→CH_3CHO的反应.本文还探讨了不同催化剂上甲烷的吸附条件以及CO与甲烷分解所产生的表面碳物种间的反应行为.结果表明,Pd、Ni基金属催化剂表现出较为优越的催化性能.探针分子CH_3I的表面反应结果显示甲烷分解产生的CH(?)(ad)(x≤3)物种可能是该反应的活性中间体.     

二氧化碳加氢甲烷化镍锰基催化剂的研究

研究了锰组分的添加含量及制备方法对Ni/g-Al2O3催化剂上二氧化碳加氢合成甲烷的影响,并用XRD,TPR,BET等手段进行表征。研究结果表明,在常压、400℃、n(H2):n(CO2)=4:1、空速为6000h-1条件下,采用共浸渍法制备Mn-Ni/g-Al2O3催化剂,n(Mn):n(Ni)=1:2时催化剂活性达到最高,CO2转化率达到77.92%,甲烷选择性超过96%。表征结果显示,添加的锰组分较好地分布在催化剂表面,并使镍晶粒细化,增强了镍物种与载体的相互作用,催化剂更易于还原,催化活性显著提高。     

镍改性HZSM-5催化剂上甲醇芳构化反应性能的研究

采用浸渍法制备Ni改性的HZSM-5催化剂,采用BET,XRD,Py-FTIR,NH3-TPD等分析手段对催化剂进行表征。以纯甲醇为原料,在固定床微反装置上,考察不同Ni负载量改性HZSM-5催化剂对甲醇芳构化（MTA）反应性能的影响。实验结果表明：Ni的引入使催化剂产生了比较稳定的新L酸位;随着Ni负载量的增加,Ni/HZSM-5催化剂的总酸量增加,尤其是弱酸酸量;MTA反应的芳烃总收率随着Ni负载量的增加呈现先减少后增加然后又减少的趋势;Ni的引入可能改变了HZSM-5催化剂上MTA反应的路径,由氢转移芳构化向脱氢芳构化转变;生成的芳烃主要以C7~C9芳烃为主,C6和C10+芳烃相对较少;副产物甲烷和COx收率则随Ni负载量的增加而增加,这可能与Ni促进了甲醇的甲烷化反应有关。     

低镍S Zorb催化剂的研究

分别以醋酸镍和硝酸镍为镍源,采用浸渍方法制备不同镍负载量的吸附脱硫催化剂,在小型固定流化床反应器对催化剂的脱硫性能进行评价,考察不同镍源及镍负载量对催化剂脱硫性能及辛烷值保留能力的影响。结果表明:在相同镍负载量的情况下,采用醋酸镍为镍源比采用硝酸镍为镍源制备的催化剂具有更大的比表面积和金属分散度、更高的初始脱硫活性和平衡活性及辛烷值保留能力。