加压下规整填料塔内气液两相流返混的实验研究:气相返混系数

规整填料因具有生产能力大、分离效率高、压降低、操作弹性大、持液量低等诸多优点 ,目前已被广泛应用于精馏、吸收及萃取等多种化工单元操作中 .通常只在常压或减压条件下操作 ,而在高压或大液相负荷下 ,因流体物性的变化及流动状态的改变 ,使塔内产生严重的返混 ,塔效率显著降低 .因此 ,研究加压下规整填料塔内流体的流动状态具有重要意义 .对于加压下填料塔内气相返混的研究 ,中国台湾的ＴａｎＣｈｕｎｇ -Ｓｕｎｇ[1] 在低实验气速 (0 .0 0 2～ 0 .1ｃｍ·ｓ- 1)下做过初步的研究 ,其实验填料为散堆填料 .Ｋｕｒｔｚ[2 ] 在这方面的研究…     

0.7～1.9MPa下Mellapak 350Y填料传质性能的测定

引　言最近十几年以来 ,规整填料已广泛应用于新建的蒸馏塔以及老塔的改造中 .在常、减压操作中 ,与板式塔相比 ,在相同的分离效率下填料塔具有压降更低和处理能力更大的优点 .但在高压蒸馏操作中 ,液体的喷淋密度非常大 ,其范围在 2 0～ 10 0ｍ3·ｍ- 2 ·ｈ- 1,单位塔截面积上液体负荷的增加使得填料对液体的自分布能力减弱 ,液体易产生偏流、沟流等不均匀流动 .随着压力增大 ,充了气的液相、高的汽液相密度比值、高的汽液相黏度比值等因素都会使填料床层的持液量加大 ,空隙率降低 ,其结果使规整填料处理能力受到制约 .在高压条件下 ,规整…     

高效规整填料的工业应用

随着新型填料的开发和应用,采用填料的效果要优于采用板式塔,这在许多装置的大型塔设备中已经得到很多应用。与板式塔相比较,填料塔具有效率高、压降和持液量小、放大效应不明显等特点,特别适用于分离高沸点或热敏性物质的蒸馏等过程。规整填料在石油化工等领域中得到了广泛的应用,成为提高产品产量、改进分离效果、节能降耗以及稳定操作的重要技术措施。     

规整填料塔气液传质基础理论研究进展

填料塔中气液两相的流体流动与分布、返混、传质问题一直是影响填料塔传质性能的重要因素,对规整填料塔内的气液两相流动与分布、返混、气液两相在常压和高压下的传质特性、Marangoni效应以及计算流体力学(CFD)在规整填料塔中的应用等方面的国内外研究进展进行了综述.     

化肥厂节能和规整填料

精馏过程节能问题已引起民广泛关注。采用规整填料代替和改造板式塔和散堆填料是有效的节能手段。文章对规整填料,散堆填料和塔板性能进行了比较,计算了塔设备的能耗,并鲁举了精馏塔的应用实便。     

高通量催化精馏规整填料的流体力学性能

介绍了一种可应用于催化精馏工艺的高通量催化精馏规整填料(HCCP),并对其流体力学性能进行了研究与讨论。以空气-水物系为介质在内径为400 mm的冷模精馏塔内进行实验,测量了该填料的干湿塔压降、持液量等流体力学性能。高通量催化精馏规整填料在结构方面进行了改进,使催化剂装填量可控,实验结果表明:填料在降低塔内压降、增加通量方面具有明显优势。最后对实验数据进行回归,获得经验关联式;实验测量值与公式计算结果吻合较好,这表明,数据回归获得的关联式可用于预测一定操作条件下填料的流体力学性能,用于工业实践及设备放大。     

高压下高比表面丝网规整填料传质性能的测试

引言 20世纪70年代以来,填料塔已广泛地应用于精馏、吸收、解吸和萃取等工业分离过程.     

填料塔基础理论研究新进展

规整填料塔具有效率高、压降低、放大效应不明显等优点,其成功应用有赖于对二相流动与传质的深入认识。文中综述了规整填料塔内的气液二相流动与分布、返混、气液二相在常压和高压下的传质特性、M arangon i效应以及计算流体力学(CFD)在规整填料塔中的应用等方面的国内外研究进展。填料塔内液体的分布与返混的研究较多,气相的流动分布与返混特性的研究较少,高压传质、M arangon i效应,特别是利用计算流体力学(CFD)模拟填料塔内的液体流动与传质等已逐渐成为研究的热点。     

规整填料和散堆填料传质性能比较

通过对苯 -甲苯精馏传质系数的计算 ,比较了规整填料 ( 2 5 0 Y)和散堆填料 ( 5 0 #鲍尔环 )的传质性能。结果表明 ,规整填料的传质性能优于散堆填料。这一优势主要得益于前者的比表面积远大于后者。若以传质系数 k L、k G来比较 ,新型散堆填料要强于规整填料。如何提高规整填料单位面积的传质强度是新型规整填料发展的重要方向     

规整填料塔精馏的Marangoni效应

选用 6种代表性物系对陶瓷板波纹和不锈钢丝网规整填料进行全回流精馏实验 ,考察Marangoni效应对规整填料液体流动分布及传质的影响 .结果表明 :对纯有机体系 ,Marangoni效应影响较小 ;而对有机物的水溶液 ,Marangoni效应严重影响着填料的润湿和传质效率     

规整填料在高压精馏条件下的传质性能

Performance of Mellapak 250Y and 350Y corrugated structured packing in distillation applications at pressures ranging from 0.3 to 2.0MPa is analysed by using HTU-NTU method.These data are obtained in distillation column with 0.15m diameter operated with n-butane/n-pentane system at total reflux.In considering the axial backmixing effects.the height of an overall gas phase transfer unit,HTUOG,is divided into two parts.One part represents the height of an overall gas phase transfer unit,without backmixing, designated as HUTOG,and the other part,designated as the height of a backmixing unit(HBUO),accounts for the backmixing effects.The HTUOG is evaluated from the measured concentration profile of n-butane in liquid phase.The HBUO obtained experimentally is correlated in terms of the properties of the materials being separated and the equivalent diameter of the structured packing.Our result shows that HBUO varies from 0.12 to 0.34m as pressure increases from 1.0 to 1.9MPa.It indicates that the overall efficiency of the structured packing decreas gradually at high pressure,as a result of the vapor backmixing.     

孔板波纹填料的结构参数对其性能的影响

在内径Φ30 0mm的填料塔中研究了孔板波纹填料的结构参数对液相轴向混合特性、流体力学和传质性能的影响 .研究结果表明 ,轴向返混参数随开孔率、倾角的增加及盘高的减小而增加 ,填料层压降随开孔率、盘高的增加及倾角的减小而降低 ,传质单元高度随倾角的增加、盘高的减小而降低 ,开孔率对传质单元高度的影响有一个适宜值 .通过对实验数据的回归分析得出了轴向返混参数、填料层压降及传质单元高度的关联式 .该研究结果对孔板波纹填料的开发与设计具有参考价值     

加压下板波纹规整填料塔中液相混合行为

采用脉冲示踪法测量了在0．3MPa、0．5MPa和0．6MPa压力下以及在一系列液速和气速下250Y型孔板波纹规整填料内液相的混合行为。应用时域最小二乘法由实验数据得到了液相的轴向返混系数和轴向有效流速等参数,并以y=aReL^e10^cReG10^dp的形式对轴向Peclet准数进行了关联。本研究补充了目前缺乏的加压操作下规整填料液相混合行为的数据。     

规整填料内气液两相流动与传质的计算传质学模型

Detailed investigation of flow behavior in structured packing distillation columns is of great importance in accurate prediction of process efficiency and development of more efficient and optimal equipment internals. In this study, a three-dimensional two-phase flow model based on VOF method for simulating the hydrodynamics and mass-transfer behavior in a typical representative unit of the structured packing is developed. In the proposed model, the model is used for the closure of turbulent mass transfer equation. By solving the proposed model, the velocity distribution, phase fraction profile and concentration field are obtained. Using these data, the total liquid holdup, the wetted area and the separation efficiency [height equivalent to a theoretical plate (HETP)] are estimated. For testing the model validation, the simulated HETPs are compared with our previous experimental data obtained in a 150 mm-diameter column containing Mellapak 350Y operating at the pressures of 0.6-1.8 MPa. The compari-son shows that they are in satisfactory agreement, with an average absolute deviation (AAD) of 25.4%.     

在高压下规整填料中的流动实验研究

Both distillation performance and hydrodynamic study for backmixing by tracer technique were carried out in a high-pressure packed column with 0.15 m inner diameter over a wide range of operating conditions. Isobutane and n-pentane are employed as test mixture in the distillation experiment and air/water is used for the hydrodynamic study. The column is installed with Mellapak 350Y structured packing and the total packing height is 2.0 m. With the increasing operating pressure, the separation efficiency increases slightly while the F-factor corresponding to the maximum efficiency at each pressure is descending. It is noted that, at all operating pressures, with the increase of F-factor, the packing efficiency is slightly higher up to the flooding point. The application of SRP model to high-pressure distillation gives much lower values of HTUOG than those obtained experimentally. An additional term, the height of mixing unit, is introduced to correct the SRP model and improve its accuracy at high pressure. From the tracer experiments, the height of mixing unit for gas phase was found to be larger than that for the liquid phase. From this viewpoint, it is believed that the gas phase backmixing gives more unfavorable influence on the separation efficiency in comparison with liquid phase.     

孔板波纹填料结构参数对液相轴向混合的影响

在内径300mm的填料塔中,以空气-水-氯化钾为物系,研究了孔板波纹填料的结构参数对液相轴向混合特性的影响。研究结果表明,轴向返混参数Pe随开孔率、倾角β的增加及盘高H的减小而增加。该研究结果对孔板波纹填料的开发与设计具有参考价值。     

混合池模型推算气液返混对精馏效率的影响

精馏操作过程中 ,气液返混现象对精馏传质效率有重要影响。为预测其影响规律 ,文内针对含有错流塔板且气相预混合的精馏塔 ,提出了气液返混发生时计算精馏效率的混合池模型。所得计算结果与实验数据的比较说明模型是可靠的。在此基础上 ,根据计算结果 ,探讨了不同情况下气液相返混对精馏效率的影响 ,发现气体返混和液体返混的发生均导致板效率下降 ,且过程的汽提因子和点效率越大 ,板效率随返混的发生而下降的速度越快。     

Characterization of a New Structured Packing by Computational Fluid Dynamics

The novel wire gauze structured packing PACK‐1300Y with high specific surface area was characterized by computational fluid dynamics. The main features of PACK‐1300Y were investigated including the dry and wet pressure drop as well as the height equivalent to a theoretical plate (HETP). Moreover, the flow structure of this packing was described via numerical simulations. To evaluate the amount of HETP and dry and wet pressure drop, 3D computational fluid dynamic modeling with respect to the Eulerian‐Eulerian multiphase approach was applied. The average relative errors were determined between the findings achieved from computational fluid dynamic simulation and experimental findings for mass transfer efficiency and wet and dry pressure drop, respectively.     

塑料异型矩鞍填料的流体力学及传质性能研究

在内径300 mm塔中,以空气-氨-水为物系,对开发出的一种新型塑料散装填料———异型矩鞍填料的流体力学及传质性能进行了研究。获得了该填料的几何特性、流体力学性能及传质性能数据,并通过对实验数据的回归分析,得出了填料层压降Δp/Z、泛点填料因子F及气相总传质单元高度HOG的关联式。研究结果表明,塑料异型矩鞍填料具有通量大、压降低、气液分布均匀及传质性能优良等优点。     

从浓度分布评价填料塔性能

精馏塔性能的优劣通常可以用在塔顶和塔底取样,然后计算其分离效率的方法来判断,但这种方法只可以判断出精馏设备效率的高低,却几乎无法找出造成设备效率不够理想或低效的原因．不良初始分布、壁流、沟流和溪流、端效应以及气相或液相返混等现象都可以造成填料塔效率的下降,而