A small amount of CO2 in syngas (CO/H2) is beneficial to methanol synthesis over Cu-based catalysts. To obtain more information on the CO2 effect, a series of binary Cu-based catalysts including Cu/ZnO and Cu/MgO were prepared and evaluated under feed gas (CO/H2/Ar) with or without CO2. Evaluation results show that when CO2 was added, the CO conversion of Cu0.6ZnO0.3 catalyst jumped from -4% to -68%, while the activity of Cu/MgO catalyst decreased from -15% to -0% (230 degrees C, 4 MPa, 8000 h-1 with 78.5% H2, 12.75% CO, 1.75% CO2 and 7% Ar). In situ X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were employed to examine the states of catalysts under different treatment conditions. The migration and transformation of metal species on the catalysts surface should be a reason that caused the opposite change of catalysts activity with and without CO2.

对自主研制的甲醇合成催化剂进行工艺参数优化,同时根据实验结果对合成气条件下甲醇合成的反应机理进行探讨.实验采用16通道反应器,考察反应温度和接触时间对合成甲醇反应速率的影响,确定适宜的催化剂工艺条件.结果表明,在较长接触时间下,随着温度的升高,CO转化率、H2转化率和甲醇相对含量先升高后降低,CO2转化率降低.在较低温度下,CO2转化率随接触时间延长基本不变,表明甲醇中碳元素主要来自于CO,而CO2浓度处于水汽变换反应与加氢形成甲醇反应之间的平衡状态.

反相微乳液法是一种合成金属纳米颗粒的有效方法,以十六烷基三甲基溴化铵(CTAB)、正戊醇、环己烷、金属盐溶液构建反相微乳液体系,制备了一系列用于合成甲醇的纳米铜基催化剂,并分别对其结构、形貌和活性进行了表征.结果 表明,催化剂制备过程中的老化温度、碱浓度、H2O/CTAB的摩尔比以及盐溶液的浓度对催化剂的粒径和活性均有一定的影响,为甲醇合成催化剂的新型制备方法提供了借鉴.

Aluminum is an essential ingredient in the ternary Cu/ZnO/Al2O3 catalyst for methanol synthesis from syngas. This work investigated the effect of Al-containing precursors on Cu/ZnO/Al2O3 catalysts during catalyst preparation. A series of Cu0.6Zn0.3Al0.1 catalysts with various Al-containing precursors, including Cu-Zn-Al hydrotalcite, aluminum hydroxide and Zn-Al hydrotalcite, were prepared by co-precipitation and fractional-precipitation, respectively. The catalysts were characterized with XRD, TG, XRF, N2 physisorption, N2O chemisorption, SEM, TEM/EDS and TPR. Results show that the Al-containing precursor has an important effect on the Cu substitution by Zn in malachite lattice, leading to various performances of the obtained catalysts. The catalyst with Al existing as aluminum hydroxide performed high Cu substitution in the co-precipitated zinc malachite, and exhibits better catalyst performance compared to its counterparts. Aluminum hydroxide can be a suitable Al-containing precursor for preparing the Cu/Zn/Al methanol-synthesis catalyst.

Aluminum is an important ingredient in the ternary Cu/ZnO/Al2O3 catalyst for methanol synthesis from syngas. The objective of this work is to investigate the effect of Al addition methods on the property of Cu/ZnO/Al2O3 catalyst. A series of Cu0.6Zn0.3Al0.1 catalysts with various Al-containing precursors were prepared by co-precipitation and fractional-precipitation methods. The catalyst samples were characterized by XRD, TG-MS, XRF, N2 physisorption and TPR. Results show that the Al addition methods have strong effect on the substitution of Cu by Zn in the subcarbonate lattice, leading to various performances of the obtained catalysts. Al addition with fractional precipitation performed higher substitution of Cu than that with the traditional co-precipitation method. And thus, it can be a promising method for preparing the Cu/ZnO/Al2O3 methanol synthesis catalyst.