超高碱值环烷酸钙的合成及添加剂间的相互作用

文中主要介绍了超高碱值环烷酸钙的合成工艺过程,合成产品的理化性质良好,红外光谱测定出产品胶体结构碱性中心CaCO3晶体状态为无定型.同时,采用相容性试验和复配试验考察了该剂与硫化烷基酚钙和超高碱值石油磺酸钙的相互作用.     

超高碱值环烷酸钙的研制

以环烷酸、氢氧化钙和二氧化碳为原料,二甲苯为溶剂,甲醇为促进剂,合成了超高碱值环烷酸钙,考察了溶剂、促进剂用量及二氧化碳的通入速度对超高碱值环烷酸钙合成过程的影响。结果表明,从合成产品本身的性质和工艺经济性考虑,溶剂的适宜用量为125~200 g,促进剂甲醇的适宜用量为12~25 g,二氧化碳通入速度为80~100 mL/min。在实验室优化工艺的基础上,进行了中型放大实验,产品质量稳定。     

旋转填充床传质及应用研究的新进展

旋转填充床(RPB)是一种新型高效的分离装置,该装置利用超重力场技术强化传质过程,在化工、环保、材料、生化等工业领域具有广泛的应用前景。本文概要地介绍了该装置的结构特点,国内外传质和应用研究的新进展。     

激光衍射法测试超高分子量聚乙烯粒度分布的影响因素研究

目前,激光衍射法测试超高分子量聚乙烯(UHMWPE)的粒度分布使用无水乙醇作为分散剂,由于无水乙醇具有危险性大、废液处置难等缺点,本文以水作为分散剂,以聚氧乙烯辛烷基苯酚醚为表面活性剂开展试验,研究了表面活性剂加入量、样品质量、搅拌速率、测试时间等因素对UHMWPE粒度分布测试结果的影响。研究表明,当表面活性剂的加入量为0.2～0.3 mL,样品质量为600～700 mg,搅拌速率为2 000～2 200 r/min,测试时间为15 s条件下,测试结果的重复性好且准确度高,适用于UHMWPE的粒度分布测试。     

聚乙二醇对旋转填充床制备La_(0.5)Pb_(0.5)MnO_3载体的影响

采用旋转填充床液液相共沉淀法制备了钙钛矿复合氧化物La0.5Pb0.5MnO3,以其作为载体制备了0.5%Pd(质量分数)/La0.5Pb0.5MnO3催化剂合成碳酸二苯酯。为了提高催化剂的活性,采用聚乙二醇(PEG)为分散剂对载体表面改性,通过XRD,SEM,BET手段对其物性进行表征,并对催化剂进行了活性评价。结果表明:PEG良好的空间位阻效应可以增加载体的分散度和比表面积,提高催化剂的活性。PEG10 000浓度为0.001 5 mol/L时效果最佳,载体比表面积达53.73 m2/g。反应温度65℃,总压5 MPa,p(CO)∶p(O2)=94∶6,反应3 h,DPC收率达13.30%。反应9 h,该条件下DPC收率可达21.90%。     

颗粒旋转对鼓泡流化床内气固两相流动特性影响的数值模拟

运用考虑颗粒自旋转流动对颗粒碰撞能量交换和耗散影响的颗粒动理学方法,建立鼓泡流化床气固两相Euler-Euler双流体模型,数值模拟流化床内气体颗粒两相流动特性。分析表明,颗粒平动温度与旋转温度之比是法向和切向颗粒弹性恢复系数和摩擦系数的函数。与不考虑颗粒旋转效应计算结果相比,考虑颗粒旋转效应后床内较容易形成气泡,颗粒自旋转运动将导致床内非均匀结构更明显。并且床层平均空隙率和床层膨胀高度增加,床中心区域颗粒轴向速度提高,床内颗粒平动温度下降。考虑颗粒旋转效应后预测的颗粒轴向速度和颗粒脉动速度与文献实验结果基本吻合。考虑颗粒旋转效应后获得的气泡直径更接近于前人经验关联式。     

超声场与添加剂对鼓泡塔中传质性能的影响?

利用超声场鼓泡塔和双电导探针气泡特征参数测量仪实时测定了加入不同种类和不同浓度添加剂前后鼓泡塔内氨气气含率与传质系数变化规律。实验结果表明：无添加剂时,超声频率为20-50-100 kHz组合,功率100 W时,鼓泡塔内气含率比无超声作用时增加了37%~74%,传质系数增大了39%~61%;气含率和传质系数随加入正辛醇浓度的增大呈现逐渐增长的趋势,当正辛醇浓度超过1.0%(V)时,气含率和传质系数趋于稳定;超声频率为20-50-100 kHz组合,超声功率100 W,正辛醇浓度为1.0%时鼓泡塔内气含率比无添加剂加入时增加了20%,传质系数增大了16%,可见超声场与添加剂协同作用有利强化气液相间分布、提高传质效果。     

精馏过程中转子对旋转填料床传质性能的影响

以甲醇水溶液为介质,在全回流、常压操作条件下,对3种转子的旋转填料床进行精馏实验。结果表明：旋转填料床的理论塔板数随超重力因子、气相动能因子和回流量的增大出现峰值,等板高度最小为9．5mm。转子Ⅲ的传质效率高于转子Ⅰ,低于转子Ⅱ。在实验基础上应用最小二乘法建立了转子Ⅰ的传质关联式。     

碱度对HABR反应器快速启动及运行过程的影响

HABR反应器的启动是HABR反应器高效稳定运行的关键,其影响因素很多.为了更好地实现HABR反应器的启动,提出了2种不同启动方法的对比,即未加碱度启动过程及投加碱度启动过程.结果表明,碱度的投加能够很好地保证HABR反应器的快速启动,这种启动方式出水pH稳定,COD去除率高.碱度控制一般以保证HABR沿程最低pH不低于6.0为准,6.5以上为佳.进水碱度的下限与反应器的进水浓度密切相关.在中高负荷COD条件下(10kg·m~(-3)·d~(-1)),保持HABR运行良好的最低碱度为600mg·L~(-1).     

带阻尼内构件鼓泡塔的研究(Ⅱ)——内构件对气液传质速率的影响

采用化学吸收法实验考察了鼓泡塔内部的阻尼内构件对气液传质速率的影响.结果表明.在流速最高的塔中心区域设置阻尼内构件不但可以改善流速分布.而且还能显著地促进气液传质.在合适的阻尼面积密度范围内,安装内构件后气液传质速率可提高10%～30%,其机理是内构件的存在强化了流体的局部湍动.将鼓泡塔内大尺度的平均流动动能转化为小尺度的局部湍动动能.     

纳米碳酸钙二次粒径对有机硅密封胶力学性能的影响

采用X射线衍射仪、扫描电子显微镜、激光粒度分布仪分析了纳米活性碳酸钙的相组成及粒子结构、形貌、粒径分布;研究了几种一次粒径相近、不同二次粒径的纳米活性碳酸钙对脱酮肟型单组分室温硫化(RTV)有机硅密封胶力学性能的影响。结果表明,一次粒径小的碳酸钙,经表面处理后的二次粒径不一定小;二次粒径比一次粒径对RTV有机硅密封胶的力学性能影响更大:随着二次粒径的减小(而非一次粒径的减小),RTV有机硅密封胶的拉伸强度、断裂伸长率和硬度都呈增加趋势。     

The Effect of Bed Temperature on Mass Transfer between the Bubble and Emulsion Phases in a Fluidized Bed

The rate of interphase mass transfer between the bubble and emulsion phases of a bubbling fluidized bed is of primary importance in all models for fluidized bed reactors. Many experimental studies have been reported, however, all these investigations have been carried out in fluidized beds operated at room temperature. In this work, the effect of the bed temperature on the interphase mass transfer is reported. Single bubbles containing argon – used as a tracer – were injected into an incipiently fluidized bed maintained at the required temperature. The change in argon concentration in the bubble was measured using a suction probe connected to a mass spectrometer. The effects of bed particle type and size, bubble size, and bed temperature on the mass transfer coefficient were examined experimentally. The interphase mass transfer coefficient was found to decrease with the increase in bed temperature and bubble size, and increase slightly with increase in particle size. Experimental data obtained in this study were compared with some frequently used correlations for estimation of the mass transfer coefficient.     

Dispersion and Mass Transfer Effects on the Performance of an Immobilized Lipase Packed Bed Reactor During the Hydrolysis of Rice Bran Oil

The performance of an immobilized packed bed reactor for the hydrolysis of rice bran oil has been investigated and can be well described by a dispersion model with an average standard deviation of 0.0388. Global mass transfer coefficients estimated using the model and experimental data ranged from 0.095‐0.482 min^?1, depending on substrate flow rates. A dimensionless mass transfer correlation between the Sherwood number and the Reynolds number was obtained as NSh = 3.96 ×NRe^2.07.     

悬浮物直径和含量对岩心渗透率的影响

通过定量滤膜调整现场污水的粒度分布,采取岩心流动试验模拟方法,研究了浓度和直径不同的悬浮物注入水对地层所造成的渗透率伤害。室内岩心流动实验结果表明：岩心的物理特征大致接近时,给定悬浮物粒径,颗粒浓度越大,引起的渗透率损失越大;悬浮颗粒浓度一定时,颗粒粒径越大,引起的渗透率损失越大;以渗透率伤害15％为界,确定渗透率70 mD左右的地层,注入水中悬浮物控制标准为粒度中值2．6μm,含量3 mg／L。     

Effect of the Equipment Configuration and Operating Conditions on Process Performance and on Physical Characteristics of the Product During Coating in Spouted Bed

The effects of the configuration and operating conditions on the performance of the spouted bed tablet coating process have been studied. The configuration parameters analyzed were the ratio between the draft tube diameter and the inlet orifice diameter, d_T/d_i, and the conical base angle, γ. To analyze the equipment performance the adhesion coefficient, η, and the increase rate of the tablet mass, K₁, were measured as a function of the mass flow rate of the coating material, W_s, of the ratio between the mass feed flow rate of coating suspension relative to mass feed flow rate of the spouting gas, W*_s/W*_g, of the air flow rate relative to minimum spouting, Q/Q_ms, and of the feed flow rate of atomising air, W_at. Procedures for the evaluation of the growth kinetics and for measuring the product uniformity are presented.     

Effect of Chemical Reaction and Mass Transfer on Ozonation of the Azo Dyes Reactive Black 5 and Reactive Orange 96

Ozonation of wastewater containing azo dye has been studied to evaluate the enhancement of ozone mass transfer from O₂O₃ gas into water with the presence of chemical reactions in a bubble column reactor. Experiments were performed at different initial dye concentrations and at various gas flow rates. C.I. Reactive Black 5 (RB 5) and C.I. Reactive Orange 96 (RO 96) have been chosen as representative model substances being found in wastewater from textile-finishing wastewater. Results show that the rate of ozone mass transfer increases with increasing initial dye concentration and gas flow rate. Consequently, an enhancement factor E for ozone mass transfer with chemical reaction could be calculated which increases with dye concentration. The chemical reaction between ozone and dye enhanced the mass transfer within the liquid film of the gas liquid boundary. The greatest enhancement factor for wastewater containing RO 96 of 2050 mgL^?1 is E = 15.4 compared with E = 9.1 for RB 5 of 3800 mgL^?1, both for gas flow rates of 19 Lh^?1. For lower gas flow rates, higher enhancement factors were observed, particularly for RO 96.     

聚合物对烷基苯磺酸钠与钙离子相互作用的影响

用浊度法研究了聚合物对烷基苯磺酸钠与钙离子的相互作用的影响,不同聚合物,如聚乙烯亚胺（ＰＥＩ）、聚乙烯吡咯烷酮（ＰＶＰ）和聚乙二醇（ＰＥＧ）在同一ｐＨ条件下的研究结果表明,ＰＥＩ比后两能更好地抑制ＬＡＳ钙盐的形成。同时一聚合物在不同ｐＨ条件下的研究发现,ＰＥＩ只有在一个适当的ｐＨ范围内,即自身具有适当的电荷密度,才能很好地发挥其上述作用。在体系中存在一定量的ＡＥＯ３条件下,也观察到了ＰＥＩ在抑制     

The Effect of Initiators and Reaction Conditions on the Polymer Syntheses by Atom Transfer Radical Polymerization

The controlled/“living” radical polymerization of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), and styrene by atom transfer radical polymerization (ATRP) is reported. The effect of initiators and reaction conditions on the ATRP results was investigated. Controlled polymerizations with predictable molecular weights were performed on MMA at 40^○C and 80^○C using a CuCl/bipyridine (bipy) catalyst system in conjunction with 1-bromoethyl benzene as the initiator. The addition of a polar solvent was necessary to decrease the polymerization rate and afford low polydispersity materials. The ATRP processes followed a first-order kinetics with respect to the monomer concentration. The molecular weights of the resulting polymers were very close to their calculated values and increased with the conversion. The ATRP results of styrene showed a similar trend and revealed that CuBr/bipy or CuBr/PMDETA was a more suitable catalyst system than CuCl/bipy. In addition, it was found that controlled polymerizations could be readily carried out both in a nonpolar solvent or in bulk. Furthermore, by using the bromine-terminated polymer as the macroinitiator, diblock copolymers of PSt-b-PMMA, PSt-b-PHEMA, PMMA-b-PSt, and PMMA-b-PHEMA could be obtained. Thermal analysis and X-ray diffraction studies confirmed the amorphous structures of the resulting polymers.     

The Effect of Type and Concentration of Nano-Particles on the Mass Transfer Coefficients: Experimental and Sherwood Number Correlating

Developments in the area of nano-fluids are ongoing specifically in the area of liquid-liquid extractions in different industries. In the present study, mass transfer coefficients have been obtained experimentally in a spray extraction column in the presence of different nano-particles to develop a new correlation for the prediction of the dispersed phase Sherwood number. The results have shown that the proposed correlation can estimate the experimental drop Sherwood number with high accuracy. Also, the conceptual effect of nano-particle hydrophobicity/hydrophilicity is quantified in correlation without which the experimental data could not be fitted with an acceptable accuracy.