Chemical and Physical Properties of Copper-Based Catalysts for CO Shift Reaction and Methanol Synthesis

The modern low-pressure methanol synthesis catalysts are based on copper-containing systems such as Cu/ZnO/Al₂O₃ and Cu/ZnO/Cr₂O₃ with various compositions. These catalysts are also highly active for the low-temperature CO shift reaction. For both reactions the nature of the active sites is still an open question.     

Low-Temperature Methanol Synthesis (LTMS) in Liquid Phase on Novel Copper-Based Catalysts

Novel Cu-Cr based catalysts with alumina promotion have been prepared and studied in low-temperature methanol synthesis (LTMS) in a slurry reactor. The new method of co-precipitation from the sol state gave better results than those of three other preparation methods. From the results of temperature programmed desorption and XRD, there were more active sites in the presence of alumina.     

以合成气合成甲醇催化剂及其进展

本文概念了甲醇合成催化剂以及新型催化剂的研究开发状况,介绍了各类甲醇合成催化剂,锌铬催化剂,铜基催化剂,耐硫催化以及目前国际上研究最热的液相甲醇合成催化剂,并论述了常用催化剂优缺点。     

甲醇汽油的几种理化性能指标分析

甲醇汽油在汽车节能减排方面有着重要的意义,甲醇汽油作为汽车替代燃料的应用也越来越广泛,然而,甲醇汽油在使用过程中对发动机有很大的影响。本文主要针对甲醇汽油的抗爆性、蒸发性、热值和腐蚀性四个方面进行分析。     

改进铜基甲醇催化剂升温还原方法及优化使用

对甲醇合成系统的铜基甲醇催化剂的升温还原方法进行了改进,提出了生产过程中的优化措施,从而达到了延长催化剂使用寿命的目的。     

Gold-Supported Catalysts for Medium Temperature-Water Gas Shift Reaction

Water gas shift (WGS) reaction can lead to a reduction of the CO content in the H₂-rich gas derived from HCs reforming to about 0.5–1%. Au-based catalysts supported on CeO₂ and CeO₂-based mixed oxides were prepared, characterized and tested for a potential application in a medium temperature WGS stage. In particular, catalytic activity tests performed with a realistic reformate stream (40% H₂, 20% H₂O, 11% CO₂, 5% CO in He) showed how a 3% Au catalyst supported on CeO₂ + ZrO₂ reached equilibrium conditions at about 400 °C at WSV = 0.333 NL min^?1 g _cat ^?1 .     

CO变换催化剂的研究进展

介绍了国内外CO中(高)温变换催化剂、低变催化剂及耐硫变换催化剂的现状及研究进展。高效节能型变换工艺将是变换工艺的发展方向,开发低温、高活性和稳定性的变换催化剂将相应成为研究的主要目标。     

铜基催化剂上甲醇合成的动态反应动力学

Adsorption, surface reaction and process dynamics on the surface of a commercial copper-based cata-lyst for methanol synthesis from CO/CO2/H2 were systematically studied by means of temperature programmed desorption (TPD), temperature programmed surface reaction (TPSR), in-situ Fourier transform-inferred spectroecopy(FTIR) and stimulus-response techniques. As a part of results, an elementary step sequence was suggested and a group of ordinary differential equations (ODEs) for describing transient conversations relevant to all species on the catalyst surface and in the gas phase in a micro-fixed-bed reactor was derived. The values of the parameters referred to dynamic kinetics were estimated by fitting the solution of the ODEs with the transient response data obtained by the stimulus-response technique with a FTIR analyzer as an on-line detector.     

甲醇水蒸气重整制氢催化剂性能的研究

研究共沉淀法制备Cu/Al2O3甲醇水蒸气重整制氢催化剂，考察催化剂组成和焙烧温度对催化剂性能的影响。结果表明当Cu质量分数为30．9％，焙烧温度为500℃时，催化剂性能最佳。并采用X射线衍射（XRD），程序升温还原（TPR）和热重分析等方法对催化剂表面性质进行探讨。     

Methanol Synthesis from CO2 Under Atmospheric Pressure over Supported Pd Catalysts

Pd/ZnO catalyst exhibits high activity and selectivity for methanol synthesis in the hydrogenation of CO₂ under atmospheric pressure. PdZn alloys are formed upon reduction of the Pd/ZnO catalyst at high temperatures. The catalytic activity and selectivity are greatly enhanced upon the formation of such PdZn alloys. The turnover frequency and selectivity of methanol formation are markedly larger than those of a Cu/ZnO type control catalyst.     

一氧化碳变换催化剂的应用与发展

介绍了CO变换催化剂的发展背景,对国内外CO高温变换催化剂和低温变换催化剂进行,综述。通过比较,发现高效节能型变换工艺将是变换工艺的发展方向,开发低温、高活性和稳定性的变换催化剂将相应成为研究的主要目标。     

Deactivation of Supported Copper Catalysts for Methanol Synthesis

Binary Cu/ZnO and Cu/Al₂O₃ as well as ternary Cu/ZnO/Al₂O₃ catalysts were investigated with respect to their catalytic activity and stability in methanol synthesis. In a rapid aging test, activity measurements were carried out in combination with the determination of the specific Cu surface area. A close correlation between the loss of catalytic activity and the decrease in specific Cu surface area was found due to sintering of the Cu particles. Differences in the deactivation behavior and the area-activity relationship of each catalyst system imply that the catalysts should be grouped in different classes.     

Deactivation of Copper Metal Catalysts for Methanol Decomposition, Methanol Steam Reforming and Methanol Synthesis

Laboratory and industrial results are reviewed to elucidate the general features of the deactivation of supported copper metal catalysts in various reactions involving methanol as reactant or product. Most catalyst types are based on Cu/ZnO formulations that contain stabilisers and promoters such as alumina, alkaline earth oxides and other oxides. These additional materials have several roles, including the inhibition of sintering and absorption of catalyst poisons. All copper catalysts are susceptible to thermal sintering via a surface migration process, and this is markedly accelerated by the presence of even traces of chloride. Care must be taken, therefore, to eliminate halides from copper catalysts during manufacture, and from reactants during use. Operating temperatures must be restricted, usually to below 300°C.In methanol synthesis involving modern promoted Cu/ZnO/Al₂ O₃ catalysts neither poisoning nor coking is normally a significant source of deactivation; thermal sintering is the main cause of deactivation. In contrast, catalyst poisoning and coking have been observed in methanol decomposition and methanol steam reforming reactions.     

Methanol Decomposition and Synthesis Over Palladium Catalysts

Palladium is generally active in the catalytic decomposition and synthesis of methanol. The activity of palladium is largely affected by its support. Cerium oxide is an effective support especially when the catalyst is prepared by the coprecipitation or depositionprecipitation method which leads to a strong interaction between palladium and the support. Cationic palladium species formed in the catalyst are probably active species for both decomposition and synthesis while formation of Pd-O-Ce bonding is rather important in the synthesis reaction.     

在工业催化剂上水煤气变换反应宏观动力学

用内循环式无梯度反应器,在不同的反应条件下,测定了B106及B109两种型号的原粒度工业变换催化剂的宏观反应速率.根据实验数据关联出两种催化剂都适用的宏观动力学方程,求定了相应的模型参数.该式可用以模拟工业变换反应器.此外,并由实验数据计算了各种情况下的有效因子.整个实验及计算结果表明,这两种催化剂对气体的内扩散阻力都是相当大的.     

Influence of Zirconia Promoter on Catalytic Properties of Cu–Cr–Si Catalysts for Methanol Synthesis at High CO Conversion in Slurry Phase

The low-temperature methanol synthesis was studied using novel Cu–Cr–Si catalysts promoted by zirconia at 115 °C and 3.0 MPa in slurry phase. Zirconia addition improved significantly the catalytic performance. From the characteristic results, copper and chromium were enriched on the catalyst surface and more Cu⁺ cations were stabilized by the zirconia promotion.     

球形和圆柱形变换催化剂宏观活性评价新方法

运用“ 催化反应单元” 概念提出了球形私圆柱形变换催化剂的宏观活性评价新方法, 即催化剂分层整齐排列各粒、各层间填充细小惰性颗粒的排列方式和消除了内外扩散影响的反应器结构以这种方法所做的活性评价试验结果置信度高, 其二级反应速率常数k_T有解析解, 可以此作为变换催化剂宏观活性评价标准与催化剂的填充层数无关.     

铜系一氧化碳低温变换催化剂的改进研究

在国产铜系一氧化碳低温变换催化剂基础上,进行了降低堆密度和副产甲醇量的研究,通过对制备催化剂技术路线的改进,选择了氨络合法来制备铜、锌、铝氧化物的混合物母体,Cu/Zn为1.0~1.8时催化剂综合性能较好,考察了制得的催化剂在活性、耐热性和甲醇的生成量,并与现有工业催化剂进行了对比。在汽气比0.33的条件下,本研究的LB型催化剂初活性达到77.8%,400℃耐热2h后,活性仍达63.7%,并且甲醇生成量都比较低,工业原料制备的样品,冷凝液中甲醇生成量初期910×10-6,耐热后甲醇生成量981×10-6,并且其堆密度为1.16Kg.L-1,达到国外同类催化剂先进水平。结果表明本研究低变催化剂性能达到了较先进的技术指标,能够在低水碳比条件下使用。