NEW EQUATION FOR CORRELATING EXPERIMENTAL DATA WITH TWO VARIABLES

The equation mostly used for correlating experimental data is normal polynomial:f(x,t) = c 0(t) +c 1(t)x+c 2(t)x 2+…+c n(t)x n.However correlation with this polynomial is undesirable when the curved surface formed by experimental data is not smooth or the correlating range of correlation is too large.In this paper, a new correlating equation for this purpose is proposed.There are no undetermined coefficients in the new equation. When this new equation is used for correlating different kinds of experimental data (curved surface), smaller errors will always be obtained in comparison with the normal polynomial

钴钼基水煤气变换催化剂及其催化反应工艺

介绍了国内外CO变换催化剂的发展及其在不同变换工艺中的应用,阐述了Co-M o基催化剂的催化机理与硫化方法。通过综合分析中温变换、中温变换串联低温变换、中温变换串联两段低温变换和全程低温变换4种代表性的工艺流程,提出了高效节能型的全程低温变换工艺将是变换技术的发展方向,开发适应全程低温变换工艺的高活性和高稳定性的Co-M o基变换催化剂及其预硫化技术是今后的主要研究目标

Effects of composite oxide supports on catalytic performance of Ni-based catalysts for CO methanation

采用改良的粉末混合法制备了系列经过其它金属氧化物改性的nIO/Al2O3催化剂,并运用X射线衍射、透射电子显微镜、n2低温物理吸附-脱附、程序升温还原、程序升温脱附、拉曼以及X射线光电子能谱对催化剂进行了表征.结果显示,在300~700OC经MgO修饰的nIO/Al2O3催化剂上CO甲烷化反应活性比nIO/zrO2-Al2O3和nIO/SIO2-Al2O3的高.另一金属氧化物的加入削弱了nIO/Al2O3催化剂中nI-Al间相互作用,形成更多的活性nI物种,从而促进了反应的进行.Metal-oxide-modified NiO/Al2O3 catalysts for methanation of CO were prepared using a modified grinding-mixing method and characterized using X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, temperature-programmed reduction by H2, temperature-programmed desorption by H2, Raman spectroscopy, and X-ray photoelectron spectroscopy.The results show that the activity of an MgO-modified NiO/Al2O3 catalyst is better than those of NiO/ZrO2-Al2O3 and NiO/SiO2-Al2O3 in the reaction temperature range 300–700 °C.The incorporation of a metal oxide into NiO/Al2O3 was found to weaken Ni–Al interactions, leading to generation of large numbers of active Ni species, and this was confirmed to be responsible for the improvement in the performances of the catalysts in the methanation reaction.supportedbytheNationalBasicResearchProgramofChina(973Program;2010CB226903)~

Influence of copper content on structural features and performance of pre-reduced LaMn_(1-x)Cu_xO_3 (0≤x<1) catalysts for methanol synthesis from CO_2/H_2

A series of pre-reduced LaMn1-xCuxO3 (0≤x<1) catalysts for methanol synthesis from CO2 hydrogenation were prepared by a sol-gel method. The catalytic performances were strongly dependent on the copper content. XRD investigation revealed that the single perovskite structure could be preserved after being reduced, when the substitution for Mn by Cu was less than 50%. The Cu-doped (x=0.5) LaMnO3 was much more active than the other catalysts for reaction, showing CO2 conversion up to 11.33% and methanol selectivity close to 82.14%. The structural features of samples (x≤0.5) were studied. It was determined that copper existed as Cu+ species under reduction conditions. H2 was adsorbed on Cu+ sites and CO2 was activated on the medium CO2 active species in the lattice. The strong interaction between Cu+ and Mn inhibited the further reduction from Cu+ to Cu0 and made the fine dispersion of medium basic site to adsorb CO2, contributing to reactivity

催化剂积炭失活宏观反应动力学的研究

针对催化剂使用中积炭失活的一般性特点 ,借鉴库存集成电路长期稳定性预测研究结果 ,对现有的催化剂失活反应动力学方程进行了修正 ,并以渣油加氢脱硫反应为例加以验证 .修正后的失活反应动力学微分方程为 -da/dt=kdad·tm,其积分式为a =1+(d - 1)kdm +1tm + 1-1d -1.当m =0时 ,便成为常规的失活反应动力学方程 ;当m≠ 0时 ,可将反应时间t视为一种虚拟反应组分

甲醇对稠油热裂解降黏过程的影响

将甲醇引入稠油热裂解降黏过程,在高压反应釜中模拟井下开采稠油的温度和压力,考察了甲醇添加量、反应时间和反应温度对稠油降黏率的影响。实验结果表明,最佳反应条件为甲醇添加量(基于100g稠油)4mL、反应温度150℃、反应时间4h。在此条件下,稠油降黏率达到36.49%,而在相同反应温度和时间下,不加甲醇时的稠油降黏率仅为15.67%,表明甲醇对稠油热裂解降黏过程有促进作用。对反应后得到的甲醇相进行气相色谱分析,分析结果显示,甲醇相中存在硫化物,几乎不含烃类物质,甲醇溶解了稠油热裂解生成的硫化物,促进了稠油热裂解反应的进行,从而降低了稠油的黏度

化工专业开设新产品开发课程必要性与教学心得

本文从化工专业本科生培养目标的角度,论述了化工专业开设化工新产品开发课程的必要性,并结合化工企业技术产品创新的特点,阐述了化工新产品开发管理在化工企业研发中的重要性

Hydrothermal modification of alumina carrier

采用低温水热处理技术对-γAl2O3载体进行改性,通过XRD、SEM、BET及NH3-TPD等测试表征技术对改性后的氧化铝进行表征。研究结果表明,低温水热处理-γAl2O3时,-γAl2O3部分再水合生成湃铝石,焙烧后形成γ--ηAl2O3,此双结构氧化铝表面形态为均匀分散的球形细小颗粒,双结构氧化铝载体制备的催化剂表面酸性能与常规-γAl2O3制备的催化剂相比,强酸中心的酸强度减弱,弱酸中心的酸强度增强。γ-Al_2O_3 carrier was modified by hydrothermal treatment and characterized by XRD,BET,SEM and NH_3-TPD techniques.The results showed that γ-alumina transform to bayerite after hydrothermal treatment at lower temperature,while γ-η-alumina formed after calcination.Uniformly-dispersed fine spherical grains exist the surface of the doubly-structured alumina.Compared with untreated γ-Al_2O_3,strength of the strong acidic sites declined while that of weak acidic sites increased.国家重点基础研究发展计划(973计划)资助项目(2004CB217805

载体焙烧温度对Co-Mo/MgO-Al_2O_3变换催化剂性能的影响

通过X射线衍射、N2吸附-脱附、程序升温脱附、程序升温还原和电子顺磁共振方法研究了焙烧温度对MgO-Al2O3载体物化结构和Co-Mo/MgO-Al2O3变换催化剂性能的影响.结果表明,在600～800oC范围内焙烧的复合氧化物以MgAl2O4-xMgO-yAl2O3无定形形式存在,载体表面存在较多的中强酸-碱位,相应的负载催化剂具有较高的水煤气变换活性.在氧化态催化剂中存在较多八面体结构的Mo物种,而硫化态催化剂中含有较多氧硫包围的Mo物种.这些钼物种与催化剂的活性紧密相关

微波场中NaA分子筛膜合成规律的研究

采用微波加热技术,常压回流条件下,在多孔氧化铝载体上制备出连续NaA分子筛膜,详细考察了放置方式、碱度、钠离子浓度以及合成次数对膜形成的影响.XRD和SEM表征结果显示,竖立放置和平置在顶部有利于提高膜的连续程度;高的碱度和高的钠离子浓度都不利于形成连续膜,反而溶解膜层;凝胶体系更易抑制转晶;在较短的合成时间里,多次合成有利于形成连续致密膜