催化学报 ›› 2006, Vol. 27 ›› Issue (6): 515-521.

• 研究论文 • 上一篇    下一篇

氧化铝的改性及其在合成气直接制二甲醚反应中的应用

毛东森1,2,杨为民2,张斌2,卢冠忠1   

  1. 1 上海应用技术学院化学工程系, 上海 200235; 2 中国石油化工股份有限公司上海石油化工研究院, 上海 201208
  • 收稿日期:2006-06-25 出版日期:2006-06-25 发布日期:2010-08-28

Modification of Alumina and Its Application in the Direct Synthesis of Dimethyl Ether from Syngas

MAO Dongsen1,2*, YANG Weimin2, ZHANG Bin2, LU Guanzhong1   

  1. 1 Department of Chemical Engineering, Shanghai Institute of Technology, Shanghai 200235, China; 2 Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, China
  • Received:2006-06-25 Online:2006-06-25 Published:2010-08-28

摘要: 采用浸渍法制备了经硼、磷和硫的含氧酸根阴离子改性的γ-Al2O3, 以其为甲醇脱水活性组分,与铜基甲醇合成活性组分CuO-ZnO-Al2O3组成双功能催化剂,并在连续流动加压固定床反应器上考察了催化剂对合成气直接制二甲醚反应的催化性能. 结果表明, SO2-4改性可以显著提高γ-Al2O3的甲醇脱水活性,从而提高产物中二甲醚的选择性和一氧化碳的转化率. 此外,还详细研究了SO2-4改性条件如SO2-4含量、焙烧温度及前驱物种类的影响. 结果表明,当SO2-4含量为10%, 焙烧温度为550 ℃时,二甲醚的选择性及一氧化碳的转化率最高; SO2-4前驱物的种类对其改性效果的影响很小.

关键词: 合成气, 二甲醚, 双功能催化剂, 甲醇, 脱水, 氧化铝, 改性

Abstract: A series of γ-Al2O3 samples modified with borate, phosphate, and sulfate were prepared by the impregnation technique and physically mixed with a methanol synthesis component (CuO-ZnO-Al2O3) at a mass ratio of 1∶2 to form hybrid catalysts. The direct synthesis of dimethyl ether (DME) from syngas was carried out over the prepared hybrid catalysts under pressurized fixed-bed continuous flow conditions. The results indicated that the modification of γ-Al2O3 with SO2-4 could significantly enhance the activity for methanol dehydration and hence remarkably increase the selectivity for DME and the conversion of CO. The effects of SO2-4 content, calcination temperature, and type of SO2-4 precursor on the performance of the SO2-4/γ-Al2O3 hybrid catalyst were further investigated. The results revealed that the selectivity for methanol decreased when the content of SO2-4 increased from 5% to 10%, resulting in the increase in both the selectivity for DME and the conversion of CO. However, when the SO2-4 content was further increased to 15%, although the activity for methanol dehydration was increased continuously, the selectivity for DME decreased slightly due to the increased formation of byproducts hydrocarbons and CO2. Moreover, when the calcination temperature of SO2-4/γ-Al2O3 increased from 350 to 550 ℃, both the CO conversion and the DME selectivity increased gradually, resulting from the decreased formation of CO2. Nevertheless, a further increase in calcination temperature of SO2-4/γ-Al2O3 to 750 ℃ resulted in a significant decline in both DME selectivity and CO conversion because of the decreased activity for methanol dehydration. On the other hand, the type of SO2-4 precursors exerted no noticeable influence on the performance of the prepared hybrid catalysts.

Key words: syngas, dimethyl ether, hybrid catalyst, methanol, dehydration, alumina, modification