板式塔工作状态下塔顶挠度的计算

板式塔在工作状态下,塔体受到横向载荷作用时,塔板发生倾斜,板上介质的液面仍保持水平,塔板上介质的质心将偏离塔体的轴线.每一层塔板上介质质心的变化都对塔体产生附加的偏心载荷,附加的载荷加剧了塔顶的挠度.推导了介质重心的偏心矩公式并利用力学的叠加原理和自编的计算程序,得到附加的偏心载荷对塔顶产生的附加挠度.分析和计算的结果...     

风载荷作用下板式塔塔顶附加挠度的影响因素

通过分析板上液层非等高情况下塔顶附加挠度的影响因素,利用自编的程序得到板式塔设备参数与塔顶附加挠度的关系曲线。对比最大挠度与许用挠度,当最大挠度接近许用挠度时,塔顶附加挠度不可忽略。研究塔顶附加挠度的影响因素表明,随着板上介质密度ρL、介质液面高度hL和塔板数n的增加,塔顶附加挠度增加;随着塔板直径D和塔壁厚度δe的增加,塔体刚度增加,塔顶附加挠度减小。板式塔参数对长径比较大高塔的塔顶附加挠度影响大于长径比较小的低塔,对低塔的影响可以忽略。降低风载荷作用下塔顶附加挠度最有效的办法是增加塔壁的厚度。     

倾斜塔板漏液的三维数值模拟及实验

塔体受到横向载荷作用,板式塔的塔板倾斜,塔板上液层出现非等高。在冷模试验塔装置中以空气-水为实验介质,对倾斜塔板的漏液性能进行了实验研究。实验表明,塔板倾斜方向与液相流动方向相同时,倾斜塔板漏液小于水平塔板,倾角越大漏液越少,塔板气相操作下限减小;塔板倾斜方向与液相流动方向相反时,倾斜塔板漏液大于水平塔板,倾角越大漏液越多,塔板气相操作下限增大。利用计算流体力学的双欧拉模型对倾斜塔板的漏液状态进行了三维数值模拟,模拟结果同实验结果吻合较好。模拟结果显示,倾斜塔板在液层非等高剖面上发生不均匀漏液,倾角大的塔板在液层薄的区域发生气相沟流现象。     

65台框架支承式塔设备自振周期的实测与分析

对６５台框架塔的自振周期和振型进行实测,发现基本振型与落地塔不同,塔体呈弯曲变形而框架部分呈剪切变形。根据实测自振周期进行数理统计分析提出自振周期经验公式。并用哈密顿原理,推导出计算振型的理论公式可供设计应用。     

倾斜塔板液相三维流场的数值模拟

由于塔体受到横向载荷作用,板式塔的塔板倾斜,塔板上的液体流动发生变化。采用VOF两相流模型,利用计算流体力学(CFD)商用软件FLUENT数值计算了直径0.38 m倾斜塔板上液相的三维流场分布,模拟计算过程中选用塔板上液体持有量作为流动达到准稳态的标准。在不同液体流量和塔板倾斜角度下,对比了塔板上液面高度的模拟计算值和冷模实验塔测量的实验数据,二者吻合较好,说明所建的数学模型可以很好地数值计算倾斜塔板液相的三维流场分布。模拟结果表明,塔板倾斜时,板上液体的回流区中心偏向塔板倾斜方向,与无倾斜的塔板相比,液流方向与塔板倾斜方向相同时的回流区增大,而液流方向与塔板倾斜方向相反时,回流区面积减小。     

旋入安装的塔板结构

对于Dg900～1500mm左右塔体又需要采用分节法兰联接的板式精馏塔来讲,在塔板设计时会遇到这样一个问题:如按设计规范应采用分块式塔板形式的结构。因为塔身是分节的,塔板不需要从人孔中置入,这样,塔板的分块就显得没有必要。若采用定距管整块式塔板结     

板式塔气液传质三维与一维塔板的比较分析

板式塔的气液传质三维塔板与传统的二维塔板比较有许多特点,通过比较它们的性能,突出分析了它们在处理能力上的差异.计算实例和使用实例都表明,在同样的质量要求下三维传质塔板比二维的可提高产量一倍左右.     

新结构95型塔板的流体力学性能

引　言传统的板式塔塔板开孔率有限 ,当处理量较大时 ,压降较高 ,板效率降低 .因此开发新型大通量高效率塔板具有重要的现实意义 .本研究通过改进降液管结构和板面设计 ,提高塔板的有效传质区面积 ,开发了一种新型大通量塔板——— 95型塔板 ,因该板的有效传质区面积约占全部塔板面积的95%而得名 .本文以水和空气体系对 95型塔板进行了流体力学和流动性能试验 ,同时与传统筛板进行了比较 ,对试验测定的数据进行了关联 .1　试验装置及筛板结构参数试验塔为一直径Φ1 0 0 0ｍｍ的不锈钢塔 .塔内设置两块塔板 ,上板为测试板 ,下板为气体分布板 …     

变截面塔基本振型自振周期实用计算法

本文通过大量计算实例,并运用数理统计方法,寻求到对各种不同高度,不同直径以及单阶、多阶,荷载,刚度均不相同情况下塔体其自振特性的内在规律性,并导出了基本振型下各种不同塔体的λ_1/(sum from ■=1 to n m_iδ_(ii))值为0.891,从而求得第一振型周期公式。本文通过实例计算与精确法对比,其误差均较小,一般均在5％以内。     

格栅穿流塔塔板压降的研究

在常温下以空气和水作为介质,对格栅穿流塔板的塔板压降进行实验研究,观察格栅穿流塔板在操作时的气液接触状态,考察了不同塔板开孔率塔板的空塔气速、喷淋密度对于干板压降、总板压降、载点气速的影响。结果表明,格栅穿流塔板的气液接触状态可以分成润湿区、鼓泡区,其中鼓泡区为合理操作区域。通过实验数据分析得到格栅穿流塔板干板压降关联式、鼓泡区格栅穿流塔板总板压降关联式和格栅穿流塔板气液负荷比与空塔气速的关联式。     

Generalization of AIChE and colburn models for tray efficiency

The most important investigations on liquid weeping and entrainment in plate columns with downcomers are reveiwed. The formulae for calculating column plate efficiency under conditions of liquid weeping and entrainment have been derived on the basis of mass balance equations. The presented model is a generalization of the models of AIChE and Colburn. Sample results are shown graphically. The effect of liquid entrainment on tray efficiency predicted by the model is in agreement with experimental data of FRI.     

Interaction between partitioning porous plate and rising bubbles in a trayed bubble column

In a trayed bubble column, the structure of the partitioning plate plays an important role on the bubble behavior. This study examined the effect of the opening ratio and pore size of the plate on the bubble break-up frequency and bubble size distribution. The sieve tray was used as the partitioning plate. The opening ratio was closely related to gas cap development. The stagnation of bubble flow and a gas cap were observed with an opening ratio less than 48.5%. The gas cap increased with decreasing opening ratio and increasing superficial gas velocity. The main effect of the sieve tray could be categorized into the additional drag force and bubble break-up depending on the sieve pore size. When the sieve pore size was smaller than the Sauter diameter of the bubble swarm, the movement of rising bubbles was interrupted by the drag force applied by the surrounding mesh lines. On the other hand, when the sieve pore size was larger than the Sauter diameter, the bubbles were affected by the additional bubble break-up. After the bubbles penetrated the sieve tray, the bubble size distribution shifted to a smaller one and the Sauter diameter decreased.     

EFFECT OF BAFFLE ON TRAY UNDER OSCILLATING CONDITION

Effect of baffle on a tray under oscillating conditions has been examined experimentally. To reduce the degree of liquid mixing and liquid channeling under oscillating conditions, it is necessary to install the baffles on tray.

Experiments were conducted with the air-water system, ft was found that the pressure drop change can be expressed as a sinusoidal function and the period coincides with tray oscillation. The degree of liquid mixing decreases when the baffles are installed on tray and it also decreases with the increase of liquid flow rate. The pressure drop increases with the installation of baffle on tray.

The suitable baffle number on tray is from 4 to 8 and in this region, the degree of liquid mixing reaches minimum and the liquid holdup takes a maximum value. @KEYWORDS: Tray, Oscillating, Liquid mixing, Baffle, Pressure drop, Liquid holdup.     

倒锥形填料筐精馏塔板的性能研究

提出了一种新型高效塔板——倒锥形填料筐新型精馏塔板(RTPLT),在冷模塔内对该塔板的流体力学性能和塔内液体停留时间分布情况进行了研究。由实验数据关联得到了干板压降、湿板压降和漏液率的经验式。结果表明:RTPLT具有塔板压降低、雾沫夹带小、处理能力大等优点,其塔内液体停留时间分布的主要因素是液体流量。     

Hydrodynamic and Mass Transfer Performances of a New SiC Foam Column Tray

The hydrodynamic performance of a novel SiC foam column tray (SFCT), made of thin slices of SiC foam material with a high specific surface area, is investigated. The performance parameters include pressure drop, entrainment, weeping, and clear liquid height. The tests are carried out with an air‐water system under atmospheric pressure. The mass transfer efficiency of the new SiC foam column tray is studied in a stainless‐steel plate column. The results provide some important parameters for the development of this innovative SiC foam tray.     

气体折流塔板流体力学和传质实验研究

对气体折流塔板的流体力学和传质进行了实验,找出了气液流动对塔板压降和传质的影响规律,通过气体折流塔板与传统筛板在流体力学与传质等方面的比较,找到了气体折流塔板的适用范围及相对于传统筛板的优点,为以后此塔板的应用提供了有效数据。     

上置加热管筛板蒸发器流体力学及蒸发性能

对筛板上方液层内置有水平加热管束的载气蒸发器的流体力学和蒸发性能进行了实验研究,并对实验结果进行了分析。结果表明,在气速一定时,筛板单板阻力随着液体流量的增大而提高;在液体流量一定,气速较大时筛板单板阻力不随气速而变化;随着液体温度的提高,筛板单板阻力明显减小;在相同条件下,上置管束的筛板单板阻力比普通筛板单板阻力明显增大。对于常温下的空气水体系,在相同条件下,加热管束通入加热蒸汽可使出口空气的湿含量提高8. 7%—12. 6%。随着加热管束通入蒸汽流量的增加,出口空气的湿含量进一步提高。     

立体传质塔板板上液相速度场的实验研究

在1 000 mm的冷模实验塔内采用热膜测速仪对立体传质塔板(CTST)的板上液相速度分布进行了实验研究。得到了CTST板上液相在平面上的速度分布特征;在液层高度方向,液相速度分布在塔板进口、出口和帽罩的底隙附近,分别具有不同的特点。考察了堰高、液体流量、板孔气速对板上液相流场的影响。测量结果表明,罩内气体的提升作用对板上液相流场影响较大,底隙附近的液体速度与进入塔板的液体速度之比随堰高和板孔气速的增大而增大,随着液体流量的增大,该比值减小到一定程度后略有回升。     

Periodic cycling of plate columns: Analytical solution

An analytical solution of the equations for periodic cycling of plate columns has been obtained in a closed form which is suitable for rapid calculation on a computer. The solution covers a wide range of parameters including the slope of the equilibrium and operating lines, plate efficiency, fraction of the liquid holdup transferred per cycle and the number of plates in the column. It is shown that under certain conditions improvements of more than 100% in the separating ability of plate columns are theoretically possible when the column is operated in the periodic cycling mode.