Kinetic analysis utilizing a recirculating flow reactor system

A system which recirculates reactants from a stirred vessel through a remote reactor is described. Highly reproducible kinetic measurements are achieved for liquid phase reactions in general and those requiring isolation in particular. Typical reactions which require isolation involve high pressure, intense radiation, explosive mixtures, etc. The conversion history within the vessel is related to reaction rate through a mathematical model which facilitates interpretation of kinetic data. The stirred vessel is modeled as a perfectly uniform reservoir coupled to the arbitrary reaction element by two transfer lines modeled as time delays. The analysis includes the effects of a parabolic velocity profile attendant to the use of low circulation rates or high viscosities. Analytical solutions are obtained for limiting cases and the model system simulated on an analog computer. The results are compared to experimental data on a radiation induced vinyl polymerization     

A fully automated liquid-liquid extraction system utilizing interface detection

The development of the Abbott Liquid-Liquid Extraction Station was a result of the need for an automated system to perform aqueous extraction on large sets of newly synthesized organic compounds used for drug discovery. The system utilizes a cylindrical laboratory robot to shuttle sample vials between two loading racks, two identical extraction stations, and a centrifuge. Extraction is performed by detecting the phase interface (by difference in refractive index) of the moving column of fluid drawn from the bottom of each vial containing a biphasic mixture. The integration of interface detection with fluid extraction maximizes sample throughput. Abbott-developed electronics process the detector signals. Sample mixing is performed by high-speed solvent injection. Centrifuging of the samples reduces interface emulsions. Operating software permits the user to program wash protocols with any one of six solvents per wash cycle with as many cycle repeats as necessary. Station capacity is eighty, 15 ml vials. This system has proven successful with a broad spectrum of both ethyl acetate and methylene chloride based chemistries. The development and characterization of this automated extraction system will be presented.     

Behavior of three-way catalyst in a hybrid drive system

The dynamic behavior of a Pt-Rh/CeO₂-Al₂O₃ three-way catalyst (TWC) under pulsed flow operation conditions (intermittent mode), such as occur in a newly developed hybrid drive system, has been studied experimentally in a laboratory apparatus with simulated exhaust gas. The parallel hybrid system is based on the combination of an Otto-cycle engine with an electric motor and a flywheel providing a short-term energy storage. This configuration permits intermittent charging of the flywheel by the combustion engine which runs only during about 10% of the driving time. Each exhaust gas pulse (duration typically ca. 3 s) is proceeded by an air pulse, which results from the filling of the engine cylinders with air at start up and shut off. Experimental studies indicated that the air pulses have a negative impact on the performance of the catalytic converter, reducing the inherent benefits resulting from the intermittent operation mode of the combustion engine. Forced asymmetric λ-cycling during exhaust pulse was found to be most beneficial for improving catalyst performance. A simple reduced kinetic model derived from a Langmuir-Hinshelwood model for CO oxidation, which was extended by introducing CO and O₂ equivalents to mimic the complex exhaust gas, was used to describe the dynamic behavior of the TWC. The model proved to be useful for finding the optimal λ-cycling conditions. Experiments with the real Otto-cycle engine exhaust proved that the reduced kinetic model is suitable for use in a closed loop λ-control.     

A novel optical aerosol detector utilizing an optic fiber with conductive polymer coating

The detection of atmospheric aerosol particles is becoming an important issue in many fields such as environmental science, occupational medicine, semiconductor industry and material science. In the present paper, we utilized the conductive polymer, polypyrrole (PPy), as a sensitive membrane for detecting aerosol particles optically. A polymer optical fiber reflectance probe is constructed by depositing the PPy nanofilm at the end face of the fiber. The sensor principle relies on the change in the refractive index of the PPy nanofilm upon its interaction with aerosol nanoparticles and on the electrostatic induction between aerosol particles and the PPy nanofilm, which leads to a change in the reflected intensity. For preliminary evaluation of optical aerosol detector, three types of aerosol particles, NaCl, black carbon (BC) and polystyrene latex (PSL), are selected. The fabricated fiber optic reflectance probe using the PPy nanofilm shows distinct variations in the reflected light intensity depending on the type of aerosol particle and its properties. The proposed sensing approach may promote the use of conductive polymers in optical techniques for the detection of atmospheric aerosols.     

转鼓闭式造粒技术研究

磷复肥转鼓造粒是采用粉体配料、团聚造粒的方法。本文为提高转鼓一次造粒合格粒子的比例和改善操作环境提供了新技术     

一种新型蛋白质沉淀体系——加压CO2-乙醇-水体系

将有机溶剂抗溶剂与高压气体等电沉淀技术结合起来,提出了一种新的蛋白质纯化方法.实验以加压CO₂为挥发性酸,乙醇为助沉淀剂,对BSA的等电沉淀进行了研究.由实验结果可知,本方法可使BSA处理浓度提高,CO₂操作压力降低,其中乙醇既具有促进沉淀的作用又具有降低BSA缓冲能力的作用.蛋白质稳定性测试结果表明,在实验操作条件下,BSA未发生不可逆的构象变化,能保持稳定.这些结果对该方法的进一步完善及其在蛋白质等生物活性成分分离纯化领域的应用具有借鉴作用.     

Spherical agglomeration in a conical drum

The spherical agglomeration process is a means of size enlargement in which agitated particles, suspended in a liquid, are bonded together by a second liquid, which will wet the solid surfaces and be immiscible with the suspending medium. A process is described in which agglomeration takes place in a cone shaped vessel, rotating horizontally about its symmetric axis. The cone configuration of the agglomerator imparts a longitudinal impulse to the charge, which is most effective on the largest particles. This causes a size classification within the cone, with the largest agglomerates congregating at the base. The result is the continuous production of uniformly sized, highly spherical pellets. The factors affecting agglomerate growth and size are outlined and discussed.     

Paint primer system utilizing polyvinyl fluoride film

A new generation of polyvinyl fluoride film has been specifically developed for use as a primer surface for automotive components which cannot otherwise be decorated with regular OEM paints, or where improved adhesion between the paint and the part is desired. Special film surface modifications provide for excellent adhesion between the film and a broad range of OEM and refinish paints. Lab and proving ground testing demonstrate solid performance throughout the exposure cycles required by FBMS 1–38. Current applications include vinyl and aluminum parts. The polyvinyl fluoride film is applied by lamination to extruded plastic or to coil stock using acrylic and acrylic/epoxy adhesives with proven outdoor durability. For parts subject to aggressive gravel attack, or where bonding to plastic parts is desired simply by heat fusion, a laminate of polyvinyl fluoride with a thin plastic face sheet can be used. Paints are applied according to normal operating procedures. This includes baking temperatures up to 300°F subject to the dimensional stability of the part. The chemical resistance of polyvinyl fluoride allows the use of virtually any chemical or solvent without attack to the film.     

Gelimat混料加工装置

据美国 Draiswerke公司介绍 ,该公司利用热动力学原理开发的全自动加工控制 Gelimat混料加工装置 ,可在极短的时间内对多项加工参数进行调整改动。　　Gelimat混料加工装置可在几秒钟内完成搅拌、混合、加热混料等一系列操作过程 ,因此 ,聚合物的加热过程极短 ,可防止聚合物的降解。物料受热可在5～ 2 0秒钟即达到熔融温度 ,然后再输送到成型区。　　 Gelimat混料装置可用于加工 PE、UHMWPE、PP、PVC、PVDC、ABS以及几乎所有的热塑性树脂和热固性树脂 (包括合金、高填充或纯树脂 )。Draiswerke公司称 ,价廉的回收料可以熔融或与木…     

A novel system for self-validating adhesive joints

A self-validating adhesive system is proposed in which ‘zero volume unbonds’ or ‘kissing’ bonds, which are undetectable by NDE techniques, may be filled and bonded by a secondary component in the adhesive during cure. The system shows the principal criteria required for such a smart system, and has been shown to enhance the strength of a bonded joint without undue deterioration in durability or water uptake.     

A custom ink‐jet printing system using a novel pretreatment method

A low‐cost and environmental‐friendly direct dye‐based ink‐jet printing system was developed. A novel ink‐jet pretreatment method was employed, in which the cationic fixing agent, Matexil FC‐ER, was applied as the colourless fixing ink and applied only on image areas of the fabric by ink‐jet printer. It was found that this new pretreatment method could more effectively enhance the colour strength and improve the wash fastness (greyscale ≥ 3) when compared with traditional exhaust application. The cross‐staining of non‐image areas of fabric was also apparently decreased using this new method. The light fastness of ink‐jet pretreated samples was slightly reduced as the presence of Matexil FC‐ER made dyes more sensitive to light.     

A novel cyanate ester resin/microcapsules system

Poly(urea‐formaldehyde) microcapsules filled with epoxy resins(MCEs) were applied to bisphenol A dicyanate ester (BADCy) resin to develop a novel BADCy/MCEs system. The effects of MCEs on the viscosity and the reactivity of BADCy were investigated. The mechanical properties and the hot water resistance of cured BADCy/MCEs systems were evaluated. The morphologies of the cured systems were characterized using a scanning electron microscope. The thermal property of cured systems was investigated using thermogravimetric analysis. The results indicate that MCEs may influence the reaction of BDACy. The proper addition of MCEs can significantly improve the mechanical property and the hot water resistance of cured BADCy resin. MCEs have a negative influence on the initial thermal decomposition temperature (T_d) of cured BADCy resin. POLYM. COMPOS., 2010. © 2008 Society of Plastics Engineers.     

Rate acceleration of Diels–Alder reactions utilizing a fluorous micellar system in water

A fluorous micellar system in water has been created to produce a large interfacial area between these media that retains substrates, effectively facilitating intermolecular Diels–Alder reactions due to repulsion effects from both media. Because LiFOS functioned not only as a surfactant but also as a supporting electrolyte, an electrochemical approach could be introduced to evaluate the rate acceleration effects. The measurement of the particle size distribution of the fluorous micelles clearly supported these evaluations.     

Oil agglomeration as a pretreatment for coal liquefaction

Laboratory experiments demonstrated that a variety of distillate coal liquefaction recycle oils were satisfactory agents for cleaning Illinois no. 6 bituminous coal by oil agglomeration. Ash rejection up to 41% with 98% organic recovery was attained with conventionally cleaned coal, and ash rejection up to 67% with 90% organic recovery with run-of-mine coal. Agglomerates of > 1 mm average diameter were produced under a variety of conditions. Similar results were obtained in the scaled-up production of 268 kg of agglomerates. Oils with lower hydrogen aromaticities and higher hydrogen contents performed better than more aromatic oils. Fe, Ti and Mg were selectively enriched in the ash of the product coal, while Ca, Si, and Al were selectively rejected. The mineral pyrite was rejected only ≈ 30–40% as extensively as the bulk of the ashforming minerals. The coal cleaned by oil agglomeration performed similarly to the feed coal in batch donor liquefaction tests. In continuous hydroliquefaction tests, run-of-mine coal cleaned by oil agglomeration performed substantially better than coal cleaned to the same ash level by conventional means, because of the selective enrichment of catalytic iron minerals.     

Modelling of multiple-mechanism agglomeration in a crystallization process

A three-level agglomeration model coupled with crystal growth is developed. It accounts for Brownian, laminar, and turbulent agglomeration. The desupersaturation profiles, the particle size distributions, the average sizes, and variances (or standard deviations), as well as the instantaneous agglomeration degrees for each mechanism, can be calculated as functions of time. The model is applied to the crystallization of an amorphous solid into a crystalline polymorph in a batch crystallizer. A runaway phenomenon is detected for agglomeration when crystals are switching over from the Brownian regime to the laminar one: this switchover significantly affects the desupersaturation curve and the crystal shapes.     

提高混炼质量的新型传动系统

为了使橡胶混炼设备能够适应新材料新工艺的快速发展，在现今不稳定的商业投资环境下，选择一种高度灵活性的传动系统，既能使设备保有先进性，又能很快得到投资回报，可谓为一种不可多得的投资理念，Haqqlunds公司生产的带液压电机传动系统，可使相切型密炼机的产品质量远远好于采用传统的固定速度，速比密炼机的产品质量，也可使啮合型密炼机充分利用所配置的传动功率，还可广泛用于开炼机，双螺杆压片机和压延机，业已证明，其工作可靠，维修便宜。     

15万t/a转鼓复合肥装置改造总结

通过对阳煤丰喜肥业(集团)有限责任公司15万t/a转鼓复合肥装置的改造,总结转鼓复合肥设计及生产中的注意事项,包括原料配料系统、筛分设备、除尘设备、包膜滚筒、冷却设备存在的问题及改造措施。改造后,颗粒强度由12 N提高到20 N,订单量由4万~5万t/a提高至12万t/a,年节约费用298.76万元。