反映工艺条件对管式反应器催化反应影响的转化率方程(英文)

根据幂指函数g(u)=ua+bu的特点,借用"虚拟反应组分"和"变动级数"的概念,提出了管式反应器系统中反应转化率与工艺条件的关系式XM=1-exp[-exp(A+B/Tr+CTr)Prnpo+np1prτr multiply from i=1 to m yinyo+ny1yi]为了验证该转化率方程的普适性,考察了二乙苯催化脱氢、乙苯加氢和噻吩加氢脱硫等,并利用Matlab软件分别对这三个催化体系的实验数据进行拟合.结果表明,此方程在较宽的范围内均能很好地反映温度、反应压力、空速和物料比对转化率的影响.预测结果与实验数据之间的总平均相对偏差均小于2%,说明该方程并不是针对某一特定的催化反应或催化剂,可用于大多数的管式反应器催化反应系统中

Effect of Calcination Temperature on the Structure and Catalytic Performance of K_2WO_4/Al_2O_3 Catalysts for Methanethiol Synthesis

通讯联系人. 电话/传真: (0592)2182368; 电子信箱: [email protected][中文文摘]研究了焙烧温度对溶胶-凝胶法制备的甲硫醇催化剂K2WO4/Al2O3的表面结构和催化性能的影响.表征结果显示,K2WO4在Al2O3上分散得较好,在450和550oC焙烧的催化剂颗粒大小均匀,无明显团聚现象.随着焙烧温度的升高,催化剂的比表面积减小,表面钨物种与Al2O3的相互作用减弱,与碱物种的相互作用增强,酸碱强度降低.K2WO4/Al2O3表面不含质子酸.催化剂活性与其比表面积及表面的共轭酸碱对密切相关.评价结果表明,在550oC焙烧而制得的催化剂活性最高.[英文文摘]The effect of calcination temperature on the surface morphology and catalytic performance of the K2WO4/Al2O3 catalyst prepared by the sol-gel method for the synthesis of methanethiol from methanol and hydrogen sulfide was investigated.Physicochemical characterization results of the catalyst showed that the K2WO4 is well dispersed on Al2O3,and the catalyst possesses uniform particle size after calcination at 450 or 550 oC.With increasing the calcination temperature,the specific surface area decreases,the interaction of W species with Al2O3 was weakened, but strengthened with basic species, leading to the decrease of surface acidity and basicity. No Brönsted acid was found on the catalyst surface. The catalytic activity of the catalyst is closely related with the specific surface area and the presence of conjugate acid-base pairs on the surface. Activity assay results show that the catalyst calcined at 550 oC exhibits the highest activity for the reaction.重庆紫光化工股份有限公司的经费资

Preparation and Characterization of Sinter-Resistant RhSm2O3/SiO2 Catalyst and Its Performance for Partial Oxidation of Methane to Syngas

以乙酰丙酮铑(Rh(acac)_3)和乙酰丙酮钐(Sm(acac)_3)为前驱体,用浸渍法制备了Rh/SiO_2和Rh-Sm_2O_3/SiO_; 2催化剂。采用原位红外光谱、热重分析、低温N_2吸附、X射线粉末衍射、高分辨透射电子显微镜、H_2-程序升温还原和X射线光电子能谱等实验技术对催; 化剂的制备过程,比表面积和物相以及Rh与Sm_2O_3间的相互作用进行了表征,并以甲烷部分氧化制合成气为目标反应对催化剂的稳定性进行了考察。研究; 表明:以Rh(acac)_3和Sm(acac)_3为前驱体采用简单的浸渍法即可制备出Rh平均粒径为2.3; nm且具有良好抗烧结性能的Rh-Sm_2O_3/SiO_2催化剂。在浸渍过程中乙酰丙酮化合物通过与SiO_2表面羟基形成氢键而负载于载体表面。S; m(acac)_3在SiO_2表面的单层负载量(质量分数)约为31%,对应于Sm_2O_3的质量分数约为15%,只要Sm(acac)_3的质量分; 数低于这一阈值,均可保证分解后生成的Sm_2O_3以高分散形式负载于SiO_2上,且不会因高温(800; °C)焙烧而团聚。高分散于SiO_2表面的Sm_2O_3与Rh之间存在强的相互作用,可显著提高Rh的分散度,防止其在高温反应条件下烧结,进而使低; Rh负载量的催化剂表现出良好的甲烷部分氧化制合成气反应活性和稳定性。Rh/SiO2 and Rh-Sm2O3/SiO2 catalysts were synthesized by the conventional impregnation method using rhodium acetylacetonate (Rh(acac)(3)) and samarium acetylacetonate (Sm(acac)(3)) as precursors. The preparation and catalytic properties, as well as the interaction between Rh and Sm2O3, were characterized in detail by in situ infrared spectroscopy (IR), thermogravimetric analysis (TG), N-2 physisorption (Brunauer-Emmett-Teller (BET) method), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), temperature-programmed reduction (H-2-TPR) and X-ray photoelectron spectroscopy (XPS). The performance of the catalysts for the partial oxidation of methane (POM) to syngas was also investigated. The results showed that a sinter-resistant Rh-Sm2O3/SiO2 catalyst with an average Rh particle size of similar to 2.3 nm could be synthesized using the conventional impregnation method with Rh(acac)(3) and Sm(acac)(3) as precursors. The surface silanol groups of SiO2 acted as the centers to interact with M(acac)(3) (M=Rh, Sm) molecules when SiO2 was impregnated in the M(acac)(3) solution, leading to the formation of a hydrogen-bonded M(acac)(3) layer on the SiO2 surface. In this experiment, the monolayer coverage of Sm(acac)(3) on the SiO2 surface was equal to a Sm(acac)(3) loading (mass fraction) of approximately 31%, which in turn corresponded to a Sm2O3 loading of approximately 15%. When a Sm(acac)(3)/SiO2 sample with Sm(acac)(3) loading below 31% was heated in air to approximately 360?, the monolayer Sm(acac)(3) species decomposed into highly dispersed Sm2O3 species on the SiO2 surface, which displayed superior stability against sintering at high temperature. No aggregation of the Sm2O3 species was observed even when the sample was heated to 800 degrees C in air. The strong interaction between the highly dispersed Sm2O3 and Rh plays a key role in increasing the dispersion of Rh species in the catalyst and preventing the Rh species from sintering under high temperature conditions. This factor should also be responsible for the superior activity and stability of the Rh-Sm2O3/SiO2 catalyst with extremely low Rh loading for the catalytic partial oxidation of methane to syngas.国家重点基础研究发展规划项目（2013CB933102）,国家自然科学基金（21473144,21373168）,国家基础科学人才培养基金项目（J1310024）及教育部创新研究团队项目（IRT_14R31）资

焙烧温度对甲硫醇催化剂K_2WO_4/Al_2O_3结构和性能的影响

研究了焙烧温度对溶胶-凝胶法制备的甲硫醇催化剂K2WO4/Al2O3的表面结构和催化性能的影响.表征结果显示,K2WO4在Al2O3上分散得较好,在450和550oC焙烧的催化剂颗粒大小均匀,无明显团聚现象.随着焙烧温度的升高,催化剂的比表面积减小,表面钨物种与Al2O3的相互作用减弱,与碱物种的相互作用增强,酸碱强度降低.K2WO4/Al2O3表面不含质子酸.催化剂活性与其比表面积及表面的共轭酸碱对密切相关.评价结果表明,在550oC焙烧而制得的催化剂活性最高

藏羚羊被毛纤维氨基酸含量分析

对藏羚羊被毛纤维氨基酸含量进行了测定,结果表明:藏羚羊粗毛中谷氨酸含量比绒毛高约3%,但组氨酸和胱氨酸含量仅为绒毛的66%和15.48%。藏羚羊被毛角蛋白氨基酸的组成与山羊、绵羊被毛纤维相同;但在各种氨基酸的含量比例上有一定的差异:藏羚羊绒毛的组氨酸含量为5.88%,比山羊绒和绵羊毛高约4%;胱氨酸含量为10.60%,高于其他所测山羊的绒和毛;碱性氨基酸与酸性氨基酸含量接近（14.87%,15.23%）;藏羚羊绒毛促螺旋蛋白（Paa）含量低于降螺旋蛋白（Daa）

SSZ-13和RUB-50分子筛上甲醇制烯烃的对比研究

对比研究了SSZ-13（CHA拓扑结构）和RUB-50（LEV拓扑结构）硅铝分子筛笼大小对甲醇制烯烃反应性能的影响,并采用X射线衍射、N2吸附-脱附、固体核磁共振、热重和紫外-可见光谱等技术对催化剂的结构及反应后的碳物种进行了表征.结果表明,笼尺寸较大的SSZ-13分子筛在反应中的稳定性和产物丙烯选择性均较高;而笼尺寸较小的RUB-50分子筛中乙烯的选择性较高.酸洗可以除去分子筛中大部分非骨架Al,且在一定程度上改变了分子筛的酸性,但没有显著改变产物中乙烯和丙烯的相对比例.另外,分子筛笼的大小决定了碳物种的体积,较小笼径的分子筛上可能生成较多的乙烯.因此,用于甲醇制烯烃的分子筛笼径大小对调变产物中乙烯和丙烯选择性十分重要

SSZ-13和RUB-50分子筛上甲醇制烯烃的对比研究

对比研究了SSZ-13（CHA拓扑结构）和RUB-50（LEV拓扑结构）硅铝分子筛笼大小对甲醇制烯烃反应性能的影响,并采用X射线衍射、N2吸附-脱附、固体核磁共振、热重和紫外-可见光谱等技术对催化剂的结构及反应后的碳物种进行了表征.结果表明,笼尺寸较大的SSZ-13分子筛在反应中的稳定性和产物丙烯选择性均较高;而笼尺寸较小的RUB-50分子筛中乙烯的选择性较高.酸洗可以除去分子筛中大部分非骨架Al,且在一定程度上改变了分子筛的酸性,但没有显著改变产物中乙烯和丙烯的相对比例.另外,分子筛笼的大小决定了碳物种的体积,较小笼径的分子筛上可能生成较多的乙烯.因此,用于甲醇制烯烃的分子筛笼径大小对调变产物中乙烯和丙烯选择性十分重要