基于地方特色开发的化工过程模拟实验——以变压精馏为例

基于六盘水地区海拔高、气压低的特点，开设了具有地方特色的变压精馏过程模拟实验，低压塔设定为六盘水地区大气压值。以变压精馏分离乙酸甲酯-甲醇共沸物为例，通过相图确定精馏序列及工艺流程，讨论了进料位置、回流比和塔板数等变量对年度总费用TAC的影响，对于学生掌握化工技术和经济分析具有良好的教学效果。同时，对于培养人才的工程实践能力和服务地方产业提供了有效的保障。     

内部热耦合精馏系统节能研究

针对传统精馏塔系统和内部热耦合精馏塔系统两种不同的精馏系统,以苯―甲苯物系和丙烯―丙烷物系两种理想的二组分物系分别作为研究对象,以系统的热力学效率、公用工程费用和节能百分率作为研究评价基准,模拟并研究分析压缩比、进料热状态等参数对传统精馏塔和内部热耦合精馏塔节能效果的影响,两种不同的理想物系下内部热耦合精馏系统之间的差异,并分析内部热耦合精馏节能的影响因素,为内部热耦合精馏塔内部节能研究提供参考。     

面向丙烯/丙烷吸附分离的金属有机骨架材料的高通量计算筛选

丙烯、丙烷作为分子尺寸相近的共沸物,其分离一直是化工领域研究热点。金属有机骨架(MOFs)材料因其高度可调的孔道结构,在丙烯/丙烷分离应用上已展现出诱人潜能。本文基于Core MOF 2019数据库,采用巨正则蒙特卡洛基高通量计算筛选技术,获得了分离性优异的MOFs结构,发现其拥有适中的丙烯吸附量和较弱的丙烷吸附能力,且骨架孔径为3.70～4.10?、孔隙率中等(0.35～0.44),并揭示了孔道中心吸附位的选择性与丙烯/丙烷分离系数间关系。本研究阐明了高丙烯/丙烷分离性的骨架材料的结构和性能特征,为设计MOFs实现丙烯/丙烷的高效分离提供理论指导和数据支撑。     

丙烷甲醇制烯烃共反应的热力学和动力学分析

通过计算和实验研究相结合的方法研究丙烷甲醇共进料制烯烃反应热力学及动力学过程.热力学过程采用Gibbs最小自由能法模拟丙烷甲醇制烯烃反应体系的平衡组成,同时结合响应面分析法建立了温度、压力、丙烷甲醇进料摩尔比对产物中丙烯的摩尔分数的函数关系,通过回归方程分析最佳工艺范围.热力学分析了反应条件对平衡产物的影响,随着反应温度升高,平衡产物丙烯的质量分数先增高后降低;平衡产物中丙烯的质量分数随着丙烷甲醇进料中丙烷摩尔比增高而增高,但是实际的反应状态和催化剂也是相关的,因此研究了存在催化剂情况下,丙烷脱氢和丙烷甲醇共进料反应的活化能.反应活化能动力学实验表明,通过添加少量甲醇可以降低耦合过程中丙烷脱氢表观活化能.     

负载型聚酰亚胺-ZrO2杂化膜的制备、表征与应用

 以硅藻土-莫来石陶瓷膜管为支撑体,以SiO2膜为过渡层,采用溶胶-凝胶法制备了负载型聚酰亚胺-ZrO2杂化膜(PI-ZrO2/SiO2/K-M),并采用TG-DTA,IR,BET,SEM,渗透测定和微反技术对杂化膜进行了表征和测试. 结果表明,杂化膜的成膜状况良好,厚度约为1.2 μm,平均孔径约为3 nm; 杂化膜的N2渗透通量大于1.5 μmol/(m2·Pa·s),对丙烯/丙烷的分离因子可达1.5. 以Pd-Cu/MoSiO为催化剂,以PI-ZrO2/SiO2/K-M膜管为反应器,在400 ℃下CO2氧化丙烷脱氢制丙烯反应的转化率可达11.5%,丙烯选择性为95.7%,明显高于同温度下的常规催化反应.     

乙醇水溶液与二乙氧基甲烷的萃取分离

目前DEM与乙醇水溶液的分离均采用精密精馏法[1],由于DEM的沸点与乙醇水溶液的共沸点接近,很难得到98%以上的DEM,本文以二甘醇为萃取剂,以UNIQUAC方程为模型[6],采用微机模拟逆流萃取分离结果,并进行逆流萃取试验。1　逆流萃取模拟计算以UNIQUAC方程为模型,采用二甘醇为逆流图1　液液萃取工艺流程Fig.1　liquid liquidextractiontechnicalchart萃取剂模拟计算DEM与乙醇水溶液的分离结果,工艺流程如图1所示,塔顶为萃余相③,含高纯度的DEM,塔底为富含乙醇和水的萃取相②,萃取相送精馏塔分离,精馏塔底溶剂循环使用,塔顶可得到…     

CO2消除镓氢物种提升Ga2O3/SiO2丙烷脱氢反应性能

丙烯是一种基础石油化工原料,在全球石油化工生产中占有重要地位.以丙烯为原料可生产许多石油化学品,如丙烯腈、环氧丙烷和聚丙烯等.经济快速发展带动了丙烯下游衍生物产业的发展,进而增加了对丙烯的需求量,因此尽管近年来丙烯产能逐年上升,丙烯产量与需求量之间仍存在较大缺口.传统的丙烯生产路径主要是石脑油蒸汽裂解和重质油催化裂化.然而,随着石油资源的短缺和页岩气的发展,丙烷脱氢作为一种直接生产丙烯的技术,成为丙烯生产领域的研究热点.近年来,镓基催化剂由于其较少的积碳和较高的催化活性受到了越来越多的关注.镓基催化剂在丙烷脱氢反应中的活性位点也得到了更多研究.在镓基催化剂中,镓氧化物具有丙烷脱氢活性,而丙烷脱氢反应过程中产生的镓氢(Gaδ+-Hx)物种不稳定,且会造成丙烯选择性降低,导致丙烯产率降低.因此,反应过程中原位消除镓氢物种对于提高丙烷脱氢反应性能具有非常重要的意义.本文将CO2作为温和氧化剂引入Ga2O3/SiO2催化的丙烷脱氢反应中,促进不利的中间产物Gaδ+-Hx的转化,再生丙烷脱氢的活性位点Ga3+-O,从而提高催化性能.原位红外光谱实验结果表明,CO2可有效消除Gaδ+-Hx.在不同反应温度下,引入CO2可显著提高Ga2O3/SiO2催化丙烷脱氢的转化率,特别是选择性.反应4.5 h时,3Ga2O3/SiO2催化丙烷脱氢的选择性从93％降低到89％;引入CO2后,丙烯选择性可提高到并维持在93％.Ga2O3负载量由3 wt％提高到10 wt％时,引入CO2仍可促进反应性能.当CO2:C3H8由0.5增加到3时,引入CO2带来的反应性能提升基本相同.同时,引入CO2大大减少反应过程中产生的积碳.本文对镓基催化剂丙烷脱氢活性中心的认识和提高丙烷脱氢反应性能提供了新方向.     

Te掺杂对MoPO/SiO2催化剂上丙烷选择氧化制丙烯醛反应的影响

 考察了Te的添加及Te含量对MoPO/SiO2催化剂催化丙烷选择氧化制丙烯醛反应性能的影响. MoPO/SiO2催化剂对丙烷选择氧化制丙烯醛反应的中间产物丙烯选择性较高,而Te的添加促进了丙烯向丙烯醛的转化. N2吸附、XRD、Raman、XPS、H2-TPR、丙烷脉冲、NH3-TPD和Py-IR等实验结果表明,催化剂添加Te后虽然比表面积有所下降,但单位比表面积上的酸量增加,催化剂低温可还原性得到改善,从而有利于丙烷的转化. Te可能有利于丙烯α-H的脱除和/或烯丙基的插氧反应.     

Li含量对Li/MgO丙烷氧化脱氢制烯烃反应催化性能的影响

采用浸渍法制备了不同Li含量的Li/MgO催化剂,并通过TG-DTA、N_2吸附及XRD等手段对其进行了表征;对丙烷在Li/MgO催化剂表面的两种吸附状态所占据的空间体积大小进行了计算,研究了Li含量对其丙烷氧化脱氢制烯烃反应催化性能的影响。结果表明,随着Li/MgO催化剂中Li含量的增加,丙烷转化率与乙烯、甲烷、乙烷和COx的选择性均先增加,在Li物质的量分数为3%时达到最高,然后随Li含量增加而降低,而丙烯选择性则出现相反的变化趋势。丙烷在Li/MgO催化剂上的吸附和反应同时受动力学和热力学两个因素的制约;Li负载量不同,反应活性位Li+O-分散状态也不同,导致产物分布发生变化。活性位分散度高时受热力学因素影响,有利于生成丙烯;活性位分散度低时受吸附动力学影响,更趋向于生成乙烯等其他产物。     

固相球磨法制备丙烷氧化脱氢V2O5/NiO催化剂

以不同温度焙烧制备的NiO和V2O5为前驱物,采用固相球磨法制备了V2O5/NiO催化剂,考察了前驱物的焙烧温度对该催化剂丙烷氧化脱氢制丙烯反应性能的影响,并采用x射线衍射、N2物理吸附、电感耦合等离子体原子发射光谱、透射电子显微镜、H2程序升温还原和x射线光电子能谱等对催化剂进行了表征.结果表明,固相球磨法制备的V2O5/NiO催化剂表现出较好的丙烷氧化脱氢制丙烯催化性能,当以400℃焙烧的氧化物为前驱体时,V2O5/NiO催化剂表面含有较多的未完全还原氧物种Oδ-,因而表现出了较高的丙烯选择性.在475℃反应时,丙烷转化率可达20.1%,丙烯选择性达到71.2%.     

国产硅藻土吸附尿激酶机理的研究

在常温下, 尿激酶在浙江土和吉林土表面的吸附等温线分别为V型和II型; 焙烧后两者皆转为III型。吸附等温线类型与硅藻土表面结构、孔结构、表面ζ电位有关。在400℃焙烧的硅藻土等电点值最低, 吸附量最大; 改性后, 吸附量也发生改变。本文还测定了尿激酶在硅藻土表面的吸附形态, 其吸附等温线方程符合0/(1-0)=(Kc)^1/β, 并讨论了平衡常数K和尿激酶吸附功能链段数β随温度的变化。     

DFT Study on the Effect of Hydrogen-bond Formation on the Adsorption of Aminotriazines on Graphene

DFT calculations have been performed to explore the aminotriazine adsorption on graphene surfaces.Relative energies,equilibrium geometries and electronic structures of monomer and dimer of aminotriazine molecules adsorbed at the surface were investigated and analyzed in details.It was found that the hydrogen atoms in the NH2 group of aminotriazine molecules are directed toward the graphene surface,and the adsorption energy increases as the NH2 group is added.The adsorbed aminotriazine molecules facilely form a dimer through the hydrogen bonding interactions,and the two aromatic rings of optimized structure of 2-amino-1,3,5-triazine(B) dimmer(denoted by B2) and melamine(D) dimmer(denoted by D2) are parallel to the graphene sheet.The large deviation of the averaged adsorption energy of B2 and D2 compared to monor adsorption may reflect the increase of π-π repulsion and the effect of hydrogen bond formation.The electronic structure analyses reveal that the formation of hydrogen bonds in melamine dimer has great influence on the adsorption mode at the graphene surface.     

Investigations on the influence of the substrate on the crystal structure of sputtered LiCoO2

The influence of the uppermost substrate layer on the structural properties of sputtered lithium cobalt oxide (LiCoO₂) is discussed in this work. For this purpose, bare, oxidized, and platinum-coated silicon wafers, as well as stainless steel and titanium sheets, were used as substrates. The resulting crystal structure of LiCoO₂ deposited on these substrates was analyzed and discussed. The LiCoO₂ thin films were deposited by RF magnetron sputtering with different film thicknesses. A subsequent annealing step at 700 °C was performed to induce the crystallinity of LiCoO₂. The crystal orientation was determined by X-ray diffraction. The obtained results show a strong dependency of LiCoO₂'s crystal structure on the surface the film is deposited on. However, the strong influence of the film thickness reported in previous publications could not be observed. If LiCoO₂ is deposited on the substrates with a metallic surface, a strong (003) preferential orientation is obtained for a wide range of film thicknesses. In contrast, sputtering of LiCoO₂ on bare and on oxidized silicon wafers results in a (101) dominated crystal structure for the different film thicknesses. These experiments show the importance of the characterization of LiCoO₂'s crystal structure in the intended battery setup.     

La传感器在测定铝液凝固过程中La活度研究

微量稀土加入铝或铝合金中，如果加入方法、数量、时间得当，可明显改善材料的多项性能．稀土对铝及铝合金的影响规律和作用机理，已取得了一些进展，但对稀土铝合金的热力学性质，尤其是溶解态稀土的研究少有报导［‘，2］．本工作采用L即．95C。。。。FZ。。多晶作为固体电解     

第三相界面对高分子共混物粗化过程的影响研究

共混物相分离的机理已有研究［１］．但对共混物分散相的粗化过程的研究则不多见．１９７７年，Ｃａｈｎ等［２］预言第三相界面与低分子共混物之间存在的浸润作用对相分离过程应有较大影响．近年Ｔａｎａｋａ等［３］的研究结果表明，在几何空间受限的条件下，含有小分子...     

Study on the stability of the serotonin and on the determination of its acidity constants

The present work aimed at describing the spectral behaviour of the serotonin and to evaluate its acidity constants using three different methods, using two spectrophotometry titrations and a third method that involved point-by-point analysis, which permitted to monitor closely and determine the evolution of the serotonin species in solution as a function of time. The three methods allowed estimation of three acidity constants associated to the same number of functional groups that form part of the molecule. The results given by the point-by-point analysis were: log(beta1) = 24.95 +/- 0.12; log(beta2) = 20.20 +/- 0.10; log(beta3) = 10.89 +/- 0.018.     

Effect of the temperature on the thermodynamic characteristics of the ion-exchange separation of substances on ionites

The basic results on the effect of temperature on the equilibrium and thermodynamic characteristics of ion-exchange systems and the use of this effect in developing reagentless methods for ion-exchange separation are considered.     

Simulation Analysis on the Profiles of Droplets Wetting on the Substrates

To study the structural characteristics and physical properties of droplets sitting on the inclined substrates and cylindrical surfaces, wetting experiments are conducted in different cases. The profile curves of the droplets are recorded and extracted by a CCD camera and image processing, respectively. Contact angles are figured out by fitting the profile curves and taking the derivative at the front and rear triple points. Based on the experimental results, a Surface Evolver is employed to simulate the morphological changes by minimizing the total energy of the system. Furthermore, theoretical shapes and feature parameters, including the heights and the spreading distances of the droplets, which are hard to obtain by normal experimental measurements are provided. The contact-angle hysteresis when the heavy droplet sitting on the inclined substrate is discussed. Meanwhile, the evolutions of the contour of the three-phase contact line are predicted when heavy droplets spread on the convex and concave cylindrical surfaces, respectively. This study provides a finite-element analysis method to describe the surface properties of molten droplets on different substrates, and the simulation results agree well with the experimental results.