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浆态床二甲醚合成中V2O5、Sm2O3对脱水组分γ-Al2O3的修饰作用
引用本文:谭猗生,,解红娟,崔海涛,韩怡卓,钟 炳.浆态床二甲醚合成中V2O5、Sm2O3对脱水组分γ-Al2O3的修饰作用[J].燃料化学学报,2005,33(5):602-606.
作者姓名:谭猗生    解红娟  崔海涛  韩怡卓  钟 炳
作者单位:1. State Key Laboratory of Coal Conversion , Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; 2. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
基金项目:国家高技术研究发展计划(2002AA529070).
摘    要:采用等容浸渍法制备改性脱水催化剂,通过H2-TPR、Pyridine-IR、还原态NH3-TPD、XRD等表征手段,以及目标反应浆态床CO+H2合成二甲醚,研究了催化剂的还原性能以及酸中心分布与反应性能之间的关系。H2-TPR结果表明,在脱水催化剂γ-Al2O3、V2O5/γ-Al2O3和Sm2O3/γ-Al2O3上不出现还原峰,V2O5、Sm2O3的加入改善了复合催化剂中Cu的还原性能,促进了甲醇催化剂的还原。Pyridine-IR表明,V2O5和Sm2O3的加入对L酸、B酸的量影响不大。还原态NH3-TPD说明V2O5和Sm2O3的加入改变了酸中心的分布,增加了弱酸中心的比率。XRD结果发现,V2O5和Sm2O3均匀分散在γ-Al2O3上,没有新的物种生成。二甲醚合成目标反应的结果表明,改性后催化剂的反应活性增强,合成反应中CO转化率、二甲醚的选择性都得到提高。V2O5和Sm2O3的添加增加了弱酸中心数量,促进了脱水活性,从而提高了复合催化剂合成二甲醚的活性和选择性。

关 键 词:浆态床  脱水催化剂  V2O5  Sm2O3  
文章编号:0253-2409(2005)05-0602-05
收稿时间:01 17 2005 12:00AM
修稿时间:05 25 2005 12:00AM

Effect of V2O5/Sm2O3 modification on alumina performance for slurry phase dimethyl ether synthesis
Tan YiSheng;Jie GongJuan;Cui HaiTao;Han YiZhuo;Zhong Bing.Effect of V2O5/Sm2O3 modification on alumina performance for slurry phase dimethyl ether synthesis[J].Journal of Fuel Chemistry and Technology,2005,33(5):602-606.
Authors:Tan YiSheng;Jie GongJuan;Cui HaiTao;Han YiZhuo;Zhong Bing
Abstract:Dimethyl ether (DME) is one of the best indirect liquefied products of coal. It can be used not only as the automobile fuel substitute for diesel engine, but also as the household fuel substitute for LPG. Because the oil resources in China can not meet the needs of the fast economic growth, DME is more likely to become a new generation of clean fuel. For DME synthesis in slurry phase, the stability of the catalyst is a key problem. For better understanding the deactivation mechanism of the catalyst, the experiments were designed as several individual reactions involved in the one step synthesis process, such as methanol synthesis, methanol dehydration and water gas shift reaction. Each reaction was carried out at the simulated reaction conditions like DME synthesis. In this paper, γ-alumina modified by V2O5 or Sm2O3 as the dehydration component of the composite catalyst for dimethyl ether synthesis was prepared by incipient wetness impregnation method. The DME synthesis catalysts were obtained by physically mixing the methanol catalyst and the equal granular size modified γ-Al2O3 at a weight ratio of 2∶1. The DME synthesis performances of the composite catalysts were evaluated in an agitated autoclave slurry reactor. Effluent gases were analyzed by on-line gas chromatographs using carbon sieve column and a thermal conductivity detector (TCD) for hydrogen, carbon monoxide and methane, GDX-401 column and a flame ionization detector (FID) for hydrocarbons, methanol and DME. The catalysts were characterized by H2-TPR, Pyridine-IR, reductive NH3-TPD and XRD. The H2-TPR results showed that CuO in the composite catalysts can be easily reduced with addition of V2O5 or Sm2O3. Pyridine IR and reductive NH3-TPD indicated that the amounts of Brnsted acidic sites and Lewis acidic sites change much less when the γ-Al2O3 is modified. The ratio of the weak acidic sites to the strong acidic sites increases with the introduction of V2O5 and Sm2O3. XRD patterns revealed that either V2O5 or Sm2O3 disperses well on γ-Al2O3 and there is no new compound formed. In DME synthesis reaction, it was found that the γ-Al2O3 modified by V2O5 or Sm2O3 shows higher activity and DME selectivity compared to the unmodified one.
Keywords:slurry phase  dehydration catalyst  V2O5  Sm2O3
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