异丁烷脱氢过程催化剂结焦与焦性质研究

在固定床反应装置上,采用YBD型Cr/Al_2O_3催化剂催化异丁烷脱氢,通过热分析技术研究结焦催化剂,考察反应条件对催化剂结焦量及焦性质的影响。结果表明,Cr/Al_2O_3催化剂对异丁烷脱氢有较好的催化活性,当反应温度580℃,空速800 h^(-1)时,异丁烷转化率60%以上,异丁烯选择性90%以上,异丁烯收率约60%。反应温度、空速以及异丁烯对结焦催化剂的焦含量有明显影响,当反应温度超过580℃,随着原料气中异丁烯含量的增加,催化剂的结焦量迅速增加。     

不同孔径硅胶上异丁烷脱氢性能研究

采用Cr₂O₃为活性组分,K₂O为助催化剂,以不同孔径硅胶为载体,制备异丁烷脱氢催化剂,在连续微反-色谱装置上对催化剂的反应性能进行考察,结果表明,A型硅胶与B和C型硅胶相比具有更好的脱氢性能,在负载Cr₂O₃质量分数为20%和K₂O质量分数为2%时,600 ℃条件下,异丁烷转化率为24.00%,异丁烯选择性为80.94%,SEM分析表明,高温下催化剂A和B不够稳定,催化剂C的稳定性较好。     

氢-水蒸气稀释条件下脱氢催化剂的性能

为了扩大异丁烯的来源,解决甲基叔丁基醚的生产原料问题,文中研究了使用氢气和氢气-水蒸气为稀释剂的情况下,Pt-Sn-K/Al2O3催化剂上异丁烷脱氢生成异丁烯的行为.实验发现:提高反应温度,2种稀释条件下异丁烷的转化率均得到提高,但在氢气-水蒸气稀释条件下异丁烷转化率的增长幅度更大;与单一氢气稀释相比,氢气-水蒸气混合...     

异丁烷脱氢Pt系催化剂研究进展

介绍异丁烷脱氢制备异丁烯Pt系催化剂的研究进展,表明催化剂的活性中心、载体和助剂对异丁烷脱氢反应性能影响较大。催化剂活性中心的积炭覆盖和烧结是催化剂失活的直接原因;载体的酸性有助于调变积炭的形成速率,而活性中心与助剂的交互作用可促使积炭的表面迁移;活性中心与载体的交互作用有利于减少活性中心的烧结。     

Pt系异丁烷脱氢催化剂研究进展

综述了Pt系异丁烷脱氢的研究状况,探讨了铂系催化剂的活性中心,重点总结了载体、助剂、失活这几方面对铂系催化剂的反应性能的影响,并对铂系催化剂的研究前景进行了展望.     

钾对Pt-Sn/Al2O3催化剂表面酸性及异丁烷脱氢性能的影响

考察了不同K含量对Pt -Sn/Al2O3催化剂异丁烷脱氢制异丁烯的影响,并通过比表面-孔分布测定、扫描电镜、吡啶吸附-红外等一系列表征手段探讨了K对Pt -Sn/Al2O3催化剂物理结构及表面酸性的影响.结果表明,加入K能有效降低催化剂表面的酸量,且主要表现在强L酸量的降低;随着K含量的增多,催化剂表面酸量减少,异丁...     

VOx／SiO2催化剂上异丁烷催化脱氢制异丁烯

研究了使用负载法制备的VOx／SiO2催化剂上的异丁烷催化脱氢制异丁烯的反应。使用XRD和Raman光谱技术表征了催化剂的表面结构,考察了催化剂的钒氧化物负载量、反应温度和H2／n-C4H10比对反应性能的影响。研究结果表明：钒氧化物最大单层覆盖量为9％左右,大于9％催化剂表面开始形成V2O5晶体,堵塞载体孔道,使催化剂活性位减少;V2O5负载量9％为最佳钒氧化物负载景;反应温度在590-620℃,氢烷比为1-3为最佳反应条件。同时C1-C3裂解收率受反应温度影响较大,而与氢烷比及钒氧化物负载量影响不大。     

PtSn负载量对PtSn/Al2O3催化剂上丙烷脱氢性能的影响

由丙烷直接催化脱氢制取丙烯已经成为增产丙烯的重要手段之一。以水热法制备Al_2O_3载体,采用等体积浸渍法制备不同PtSn负载量的PtSn/Al_2O_3催化剂。通过XRD、N2-吸附、拉曼光谱和H2-TPR等对其进行表征,并考察不同PtSn负载量对催化剂催化丙烷脱氢性能的影响。结果表明,在制备的催化剂中,Pt1.5Sn3/Al_2O_3具有最高的催化丙烷脱氢活性和稳定性,丙烷初始转化率高达55.6%,丙烯选择性98.1%。反应330 min后,丙烷转化率仅降约10%,选择性保持不变。     

Au-Pt-Sn异丁烷脱氢催化剂的制备

以异丁烷为原料制取异丁烯是解决异丁烯稀缺和异丁烷浪费的双赢方法,异丁烷脱氢主要问题是催化剂的研发。国内外大量研究以Pt-Sn为活性组分,但仍然存在转化率偏低和容易失活等问题,而负载型纳米Au催化剂在低温时对CO氧化表现出很高的催化活性。在原有Pt-Sn催化剂基础上,加入Au,采用等体积浸渍法制备Au-Pt-Sn催化剂,比较Au对异丁烷脱氢催化剂转化率和选择性的影响,使用小型固定床不锈钢反应器,常压、温度600 ℃、空速2 400 h^-1和临氢条件下评价其性能。发现加入一定量Au后,增强了催化剂活性,n(Au)∶n(Pt)=1.0时,异丁烯收率大于40%。考察催化剂再生前后效果差异,发现经过再生后,异丁烷转化率和选择性略低有下降,表明催化剂可以再生利用。     

新型丙烷脱氢催化剂制备及其活性评价

以MIL-101(Cr)为载体,异丙醇铝为铝前驱体,通过添加助剂钾制备新型Cr_2O_3/Al_2O_3脱氢催化剂。考察反应温度、气时空速及钾含量等因素对脱氢过程的影响。结果表明,该催化剂对丙烷脱氢过程表现出较好的催化活性。在反应温度615℃、进料量60 mL·min~(-1)、钾质量分数3.2%的条件下,丙烷转化率39.6%,丙烯选择性90.0%。     

Propane Dehydrogenation over a Commercial Pt-Sn/Al2O3 Catalyst for Isobutane Dehydrogenation: Optimization of Reaction Conditions

The applicability of a commercial Pt-Sn/Al₂O₃ isobutane dehydrogenation catalyst in dehydrogenation of propane was studied. Catalyst performance tests were carried out in a fixed-bed quartz reactor under different operating conditions. Generally, as the factors improving propane conversion decrease the propylene selectivity, the optimal operating condition to maximize propylene yield is expected. The optimal condition was obtained by the experimental design method. The investigated parameters were temperature, hydrogen/hydrocarbon (H₂/HC) ratio and space velocity, being changed in three levels. Constrains such as the susceptibility of the catalyst components to sintering or phase transformation were also taken into account. Activity, selectivity and stability of the catalyst were considered as the measured response factors, while the space-time-yield (STY) was considered as the variable to be optimized due to its commercial interest. A STY of 16 mol·kg^-1·h^-1 was achieved under the optimal conditions of T 620℃, H₂/HC 0.6 and, weight hourly space velocity (WHSV) 2.2 h^-1. Single carbon-carbon bond rupture was found to be the main route for the formation of lower hydrocarbon byproducts.     

异丁烷催化脱氢研究进展

异丁烷催化脱氢产物异丁烯可用于制备甲基叔丁基醚、丁基橡胶和聚异丁烯,也可用于合成甲基丙烯酸酯和异戊二烯等各种有机原料和精细化学品。从异丁烷催化脱氢反应机理、现有工艺和催化剂研究等方面综述了异丁烷催化脱氢的研究进展。催化剂研究主要包括催化剂的制备方法、制备条件、助催化剂的作用以及评价条件。     

Oxidative dehydrogenation of isobutane over pyrophosphates catalytic systems

The catalytic effect of metal pyrophosphates (i.e., Mn₂P₂O₇, Ni₂P₂O₇, CeP₂O₇, Mg₂P₂O₇, ZrP₂O₇, Ba₂P₂O₇, V₄(P₂O₇)₃ and Cr₄(P₂O₇)₃) on the oxidative dehydrogenation of isobutane to isobutene in the reaction temperature range of 400–600 °C has been investigated. CeP₂O₇ gives the highest isobutene yield and selectivity (71%), however, V₄(P₂O₇)₃ is the most active catalyst with an isobutane conversion of 33.5% at 500 °C. Increasing the reaction temperature results in higher isobutane conversions and lower isobutene selectivity. Reaction by-products are propylene, CO, CO₂ and traces of methane and ethylene. No oxygenate products are formed under the used reaction conditions. The sum of selectivities of CO, CO₂ and methane is approximately equal to that of propylene, indicating their formation from total oxidation of C₁ species accompanying the isobutane crack reactions. Working at temperatures higher than 550 °C, the homogeneous gas phase reactions become significant and the oxygen conversion reaches 100%. This revised version was published online in July 2006 with corrections to the Cover Date.     

添加Ni对Cu基催化剂乙炔选择性加氢性能的影响

采用等体积浸渍法制备了Cu/Al_2O_3及Cu-Ni/Al_2O_3催化剂,将其应用于乙炔选择性加氢反应。结果表明,与Cu/Al_2O_3催化剂相比,Cu-Ni/Al_2O_3催化剂的加氢活性及乙烯选择性(当反应出口尾气中乙炔物质的量分数减少到0.003%时)明显提高。通过对Cu与Ni的浸渍顺序考察发现,先浸渍Ni制得的Cu-Ni/Al_2O_3催化剂活性有所下降,但乙烯选择性提高;通过对Ni含量的考察发现,当Ni质量分数为2%时,催化剂性能最佳。