气固循环流化床能量最小多尺度环核(EMMS/CA)模型

通过对核区和环区分别建立相应的流体速度表达式改进了能量最小多尺度 (EMMS)径向流动模型 ,使模拟计算结果更趋合理 .将EMMS模型和环核 (CA)模型结合起来 ,建立了能量最小多尺度环核 (EMMS/CA)模型 ,通过EMMS模型的解可以使求解困难的CA模型得到封闭解 .运用该模型可以计算气固循环流化床中空隙率、流体速度、颗粒速度、滑移速度等动力学参数的二维分布 .模型计算值与文献报道的实验值符合较好     

循环流化床环-核流结构模型研究进展

循环流化床(CFB)反应器由于其良好的传质传热性能及操作的灵活性,广泛地应用于石油化工行业。文中就CFB反应器环核流结构模型的建模研究进展进行的总结;总结了CFB提升管反应器环核流结构模型中的充分发展段平均固含率、空隙率径向分布及边壁厚度(核半径预测)等相关数学模;此外对进一步的改进工作进行了展望。     

下行床气粒流动行为的Eulerian-Lagrangian模拟

采用计算流体力学和离散单元方法耦合模型（CFD-DEM）对二维下行床内的气粒流动行为进行了全床数值模拟。模拟结果展示了下行床典型操作条件下特有的气固动态流动结构：沿流动方向存在明显的入口控制区、过渡区和（完全）发展区;颗粒聚团并不是出现在浓度相对较高的入口区,而是在过渡区之后的发展过程中逐渐形成较多的、松散的动态聚团结构。下行床发展段呈现典型的近壁浓环结构,这与实验结果基本一致。考察了颗粒之间以及颗粒与壁面之间的碰撞参数对下行床内气固流动结构的影响,发现完全弹性碰撞颗粒体系在入口区呈现最快速的颗粒分散;而对本文研究的操作条件,颗粒碰撞参数对发展段时均流体力学行为只产生轻微的影响。     

提升管-下行床耦合反应器模拟

采用轴径向二维扩散模型对提升管-下行床耦合反应器催化裂化反应进行了数学模拟,并与提升管及下行床进行了对比.结果表明,在下行床之前耦合一段适当长度的提升管不仅可以保证原料具有较高的转化率,而且可以保证目的产品的选择性较高,缩短达到相同产品收率所需的下行床长度.这种耦合反应器充分利用了提升管与下行床各自的优势,并可以根据具体的原料及产品需求调整进料的位置以改变提升段与下行段的长度比例,实现柔性操作.     

环隙式离心萃取器内部两相流动研究进展

环隙式离心萃取器是集成液-液混合与液-液分离于一体的高性能萃取设备,其广泛应用于核工业、化工环保、有色冶金、生物医药等领域。离心萃取器具有优异的水力学特性和传质特性,这主要得益于其环隙中的泰勒涡流以及转鼓内的离心分离流等特殊流动。本文主要依据离心萃取器结构和两相流动特点,综述了环隙内气-液界面变化规律、气泡流动特性、液-液两相流型、液滴流动特性,以及转鼓内的气-液界面等方面的研究进展,还总结了环隙螺旋隔板、转鼓径向叶片等结构的优化对于两相流动、混合或分离效果的影响。在后续研究中,可以从离心萃取过程中的液滴分散和聚并机理、三相流动测试及模拟、结构的模型化设计方法等方面开展更加深入的研究。     

大型乙苯脱氢轴径向反应器的研究与开发(Ⅰ) 流体力学特性

乙苯脱氢轴径向反应器是一种催化床上部采用催化剂自封结构的新颖径向反应器 ,其催化床中的流体流动是复杂的二维流动 .在催化床的表征体积元上应用连续性方程和Ergen方程描述了其流动 ,应用有限差分法通过数学模拟得出了轴径向反应器流场 ,其结果在Φ30 0 0× 10 0 0 0的冷模装置得到了验证 .以大型乙苯脱氢轴径向反应器为背景 ,讨论了流向和触媒封高对流场的影响 ,得出径向段主要以径向流动为主 ,在催化剂封区以轴向、径向二维流动为主 ;催化剂封高是影响流场的主要因素 ,对于向心流动δ在 0 .7附近是Q_a/Q与Q_r/Q相同的等比流量点 ,对于离心流动在δ为 1.1处 ,是Q_a/Q和Q_r/Q相同的等比流量点 .δ小于此值 ,是以轴向流动为主径向流动为次的二维流动区 ;δ大于此值 ,是轴向流动为次径向流动为主的二维流动区 ;与离心流动型相比 ,向心流动型轴径向床有明显的限流作用     

R&D OF LARGE AXIAL-RADIAL REACTOR FOR ETHYLBENZENE DEHYDROGENATION(Ⅰ) HYDRODYNAMICS STUDY

乙苯脱氢轴径向反应器是一种催化床上部采用催化剂自封结构的新颖径向反应器 ,其催化床中的流体流动是复杂的二维流动 .在催化床的表征体积元上应用连续性方程和Ergen方程描述了其流动 ,应用有限差分法通过数学模拟得出了轴径向反应器流场 ,其结果在Φ30 0 0× 10 0 0 0的冷模装置得到了验证 .以大型乙苯脱氢轴径向反应器为背景 ,讨论了流向和触媒封高对流场的影响 ,得出径向段主要以径向流动为主 ,在催化剂封区以轴向、径向二维流动为主 ;催化剂封高是影响流场的主要因素 ,对于向心流动δ在 0 .7附近是Q_a/Q与Q_r/Q相同的等比流量点 ,对于离心流动在δ为 1.1处 ,是Q_a/Q和Q_r/Q相同的等比流量点 .δ小于此值 ,是以轴向流动为主径向流动为次的二维流动区 ;δ大于此值 ,是轴向流动为次径向流动为主的二维流动区 ;与离心流动型相比 ,向心流动型轴径向床有明显的限流作用     

Mn Salophen/A12O3高压催化环己烯合成环己烯酮

介绍了催化荆MnSalophen/A12O3的制备方法,并对其结构进行了表征.然后以自制的MnSalophen/A12O3为催化剂,以分子氧为氧化剂,研究了催化剂用量、反应时间、反应温度以及反应压力对环己烯转化率和环己烯酮收率的影响.结果表明,在催化剂用量:50 mg,反应时间:8 h,反应温度:100℃,反应压力:1.5 MPa的条件下,环己烯酮的收率可达50.3%.     

环戊烷/2.2-甲基丁烷萃取精馏技术开发

以大庆油田化工集团生产的环戊烷产品为研究对象,通过软件计算和实验数据比较,筛选出环戊烷/2,2-甲基丁烷萃取精馏溶剂DMF和SRKM热力学模型,采用SRKM热力学模型和PRO/II8.0等软件,开发出了剂油比为6的3000t.a-1环戊烷萃取精馏分离的工艺,环戊烷产品纯度不低于99.2%。     

气固下行流化床反应器Ⅱ气固两相的流动规律

气固下行流化床反应器气固两相流动过程是比较复杂的，沿轴向气固两相运动可分为第一加速、第二加速和恒速３个运动段，沿径向局部气体速度、颗粒速度和颗粒浓度都具有不同程度的不均匀性。而这种不均匀性是由气固两相顺重力场湍动运动所决定的。和循环床提升管相比，下行管反应器气固两相沿径向分布的不均匀性得到有效地改善，气固可以实现超短接触操作，因而是一种新型高效气固超短接触反应器     

Design of a Glass Impactor for an Annular Denuder/Filter Pack System

A glass impactor for an annular denuder/filter pack system was developed, to further the application of denuder technology in sampling atmospheric gases and particles. The glass impactor consists of an entrance section containing the inlet tube, the acceleration jet, and the impaction plate, which is mounted at the entrance to the annular denuder. The impaction plate is a removable porous glass disk which can be impregnated with mineral oil to minimize bounce-off of the collected particles during sampling. Calibration tests showed that the impactor has a 50% aerodynamic particle cutoff size of 2.1 μm, at a flow of 10 L min^?1. Particle loss experiments were conducted. Total losses on surfaces inside the impactor, annular denuder, and filter pack, determined for particle sizes ranging between 1.50 and 2.77 μm, were lower than 3%. Co-located air sampling was conducted using the glass impactor and the Harvard impactor. Mass concentrations determined using the Harvard impactor were about 10% higher than for the glass impactor because the glass impactor has a slightly lower aerodynamic particle cutoff point, while sulfate concentrations obtained from the two systems were in excellent agreement.     

聚丙烯/聚乙烯共混物环状型坯挤出膨胀和垂伸的研究

利用双螺杆挤出机将聚丙烯分别与不同熔体流动速率的聚乙烯进行共混,通过环状型坯挤出,研究了共混物的型坯膨胀和垂伸情况。结果表明,聚丙烯与较高熔体流动速率的聚乙烯共混后,其型坯直径膨胀的变化范围较宽,垂伸较明显。     

Annular Pulse Column Development Studies

Abstract

The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there, is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein.

The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases.

The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other.     

连续环状离子交换色谱分离技术

本文介绍了一种新型制备色谱分离技术──连续环状离子交换色谱ＣＡＣ，建立了二维稳定连续环状离子交换色谱的数学模型。在一定条件下经过适当转化，二维稳态ＣＡＣ过程可转化为一维非稳定色谱过程。分别改变ＣＡＣ进料浓度、进料流速及冲洗流速等操作条件，测定了ＣＡＣ对果葡糖的分离性能。同时，用固定床线性色谱理论对ＣＡＣ进行预测，其预测值与实验结果较好地相吻合。实验得出，连续环状离子交换色谱对果葡糖具有较好的分离性能。     

Effect of Cylinder Rotation on Flow Characteristics of the Annular Region in Annular Centrifugal Extractor

The flow patterns in the annular region of a 50 mm annular centrifugal extractor (ACE) were studied using phase particle image velocimetry (PIV), by which the distributions of radial velocity, axial velocity, vorticity, turbulent kinetic energy (TKE), and micromixing time of a fluid under different rotating Reynolds numbers were investigated. In the center of the annular region, both the radial and axial velocities of the fluid are close to zero, regardless of the rotating Reynolds number changes. The TKE of the fluid along the radial direction is small at center and large on the edge. The results show that the mixing process mainly occurs at the region near the outer cylinder’s sidewall, and the mixing time in this region is less than that in the internal annular region. Besides, the whole mixing efficiency is proportional to the rotational speed when the speed is below a certain level, and then gradually reaches a plateau when the speed is further increased.     

Continuous Spin Detonation in Annular Combustors

An acetylene-oxygen mixture is burned in two annular chambers 100 mm in diameter in the spin detonation regime with supercritical and subcritical differences of oxygen pressure in the annular slot. By varying the flow rates of components of the mixture, width of the slot for oxidizer injection, point of fuel injection, and initial ambient pressure, the regions of existence and the structure of transverse detonation waves are studied, and the limits of existence of continuous detonation in terms of pressure in the chamber are determined. The losses of the total pressure in the flow in oxygen-injection slots and in fuel-injector orifices are estimated.__________Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 4, pp. 99–109, July–August, 2005.     

A Rigorous Model for Annular Chromatography

Modeling of annular chromatography is refined to incorporate the influence of axial and annular dispersion. Annular and axial dispersion coefficients are measured simultaneously in an annular chromatograph using an experimental technique based on the introduction of a non‐adsorbable tracer. The annular dispersion coefficient is found to be one order of magnitude lower than the axial one. Nevertheless, annular dispersion has a more pronounced effect on total dispersion when steep concentration profiles are present. A criterion to judge whether annular dispersion is negligible is developed. If the circumferential velocity is at least 0.88 times higher than the interstitial velocity, lateral dispersion can be omitted. Based on this criterion it can be concluded that the impact of annular dispersion decreases with the radius of the annulus. Therefore, it is preferable to build annular chromatographs with a large radius and a thin annulus rather than using a small radius and a thick annulus.     

Annular bed reactor-methanation of carbon dioxide

Catalytic methanation of carbon dioxide has been studied in a new type of annular bed reactor. In this new design, the central core is packed with large inert spheres; the catalyst occupies the annular space between the inert spheres and the wall. A first-generation model, representing insothermal operation of the annular bed, prepicts improved conversion for the packed compared to the unpacked-core reactor.     

Annular Centrifugal Contactors for Solvent Extraction

Abstract

Annular centrifugal contactors suitable for laboratory use in solvent extraction work have been designed and tested for both hydraulic performance and mass-transfer efficiency. The 2-cm contactors have nominal flow rates of 80 mL/min and mass-transfer efficiencies of at least 85% as measured by the extraction of uranium. These contactors work well for organic-to-aqueous (O/A) flow ratios greater than 0.8. Multistage units allow proposed flow sheets to be tested on a continuous basis in the laboratory. Scale-up to larger plant-size units is straightforward.     

Annular expansion for enhanced orientation and mechanical properties of extruded amorphous PPESK/PES pipes

With the discovery of deeper oil fields, conventional metal pumping pipes have been proven to be ineffective in meeting the requirements for deep well oil production due to their high weights and limited corrosion resistance. Therefore, in this study, a composite of Poly(phthalazinone ether sulfone ketone) (PPESK) and polyethersulfone (PES) was used to fabricate nonmetal pipes. To enhance the mechanical properties of the PPESK/PES pipes, a self-designed annular expansion pipe extruder head was used. The circumferential burst stress and axial tensile strength of the PPESK/PES pipes subjected to 30° expansion were 73.0% and 48.9% higher than those of the unexpanded sample, respectively. When annular expansion was integrated into the extrusion of PPESK/PES/carbon fiber pipes, the axial tensile strength and circumferential burst stress were 45.9% and 88.8% higher than those of the unexpanded sample, respectively. Results of polarized infrared testing and metallographic microscopic examinations demonstrated that molecular chains present a regular orientation at a certain angle to the extrusion direction, under the effect of annular expansion extrusion. These findings highlight the efficiency of annular expansion in promoting the large-scale production of pipes.