Nye Tray Versus Sieve Tray: Experimental Study on Hydrodynamic Parameters

The hydrodynamic parameters of a Nye tray were investigated by performing experiments in a tower with a diameter of 1.22 m. Air was used as the gas phase and water was used as the liquid phase. A number of parameters such as the dry pressure drop, the total pressure drop, the clear liquid height, the froth height, and the entrainment were measured. A tray stability factor was obtained using the amount of weeping, the clear liquid height, the dry pressure drop, and the Froude number. All experiments were repeated for the matching sieve tray under the same conditions. Ultimately, advantages and disadvantages were compared, and the results demonstrated that the Nye tray has a couple of advantages over the sieve tray, except that the sieve tray is slightly more stable.     

CFD and experimental studies of liquid weeping in the circular sieve tray columns

Sieve trays are widely used in fractionating devices like tray distillation towers existing in separation and purification industries. The weeping phenomenon that has a critical effect on the efficiency of tray towers was studied by a numerical model and some experiments. The experiments were carried out in a pilot scale column with the diameter of 1.22 m that includes two test trays and two chimney trays. Weeping rates and some hydraulic parameters were measured in sieve trays with the hole area of 7.04%. Furthermore, the total weeping rate and weeping rate in inlet and outlet halves of the test tray were determined. It was also used an Eulerian–Eulerian computational fluid dynamics (CFD) method for the present study. The model was able to predict the dry tray pressure drop, total pressure drop, clear liquid height, froth height, and weeping rate simultaneously. Furthermore, the obtained CFD results were in a good agreement with the experimental data in terms of pressure drop and the model properly predicted several hydraulic parameters like the liquid weeping behavior along the tray.     

高负荷导向垂直栅板的研究(Ⅰ)——实验测定及关联

本文提出了一高负荷帽罩单元(H型),在φ600实验塔中采用水-空气系统对其流体力学性能进行研究。实验测定了各种几何尺寸及流体力学条件对塔板压降、雾沫夹带量、清液层高度和漏液点气速等的影响,并加以讨论,得出了一些能用于设计计算的半经验方程式和曲线图。     

A Novel SiC Foam Valve Tray for Distillation Columns

The novel SiC foam valve tray was made of thin slices of SiC foam material with a high specific surface area. Hydrodynamic performances of the novel SiC foam valve tray were studied with air-water system at atmospheric pressure. These performance parameters included pressure drop, entrainment, weeping and clear liquid height. The mass transfer efficiency of the SiC foam valve tray was measured in laboratory plate column. Compared with the F1 float valve tray, the dry pressure drop was decreased about 25%, the entrainment rate was about 70% lower at high gas load, the weeping was much better, and the mass transfer efficiency was far higher. Thus, the overall performance of the novel SiC foam valve tray was better than that of F1 float valve tray.     

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 …     

Hydrodynamics and mass transfer performance analysis of flow-guided trapezoid spray packing tray

Distillation is the most common separation technology utilized in the petroleum and chemistry industries. Due to the wide usage of the distillation column, even a small improvement in performance may result in significant energy cost savings. Aiming to improve the hydrodynamics and mass transfer performance, the flow-guided trapezoid spray-packing tray (FTS-PT) was designed by combining flow-guided holes and trapezoidal caps with structured packing. And the experimental measurements of the FTS-PT, including pressure drop, clear liquid height, weeping, entrainment, and tray efficiency, were conducted in a 500 mm diameter plexiglass column with the air-water-oxygen system. Moreover, the performance of the FTS-PT was compared with that of new vertical sieve tray (New VST) and F1 valve tray. The results show that FTS-PT has a significant advantage in pressure drop, entrainment, and capacity. Furthermore, the calculation model of the pressure drop was derived and used for the FTS-PT with a relative deviation of less than 5%.     

喷射式并流填料塔板流体力学和传质性能

提出一种新型高效塔板——喷射式并流填料塔板（ＪＣＰＴ），介绍１２００ｍｍ冷模塔流体力学实验结果和２００ｍｍ热模塔传质效率，给出了适用于工业设计性能参数的计算关联式。通过与新垂直筛板（ＮＶＳＴ）的比较表明，ＪＣＰＴ具有雾沫夹带小、处理能力大、塔板效率高等特点，是一种具有广泛应用前景的新型高效塔板。     

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.     

三种固阀塔板的性能比较

为了研究固阀的尺寸大小对塔板性能的影响,采用空气-水系统,在直径1200mm不锈钢塔内,对3种结构相似、尺寸不同的固阀塔板,在不同堰高、不同溢流强度的条件下进行了流体力学与传质性能测试,测定了塔板压降、漏液、雾沫夹带与传质效率。实验结果表明:随着固阀尺寸的减小,雾沫夹带降低,传质效率增高;随着阀缝面积与阀孔面积比例的减小,干板压降与湿板压降增加,漏液减少;尺寸越小的固阀,综合性能越加优异。     

网孔塔板的流体力学

木文以空气-水系统在1200×400mm矩形装置内对网孔塔板的流体力学进行了试验研究。试验所采用的塔板参数和操作条件为:塔板开口宽度为3、3.5、4、4.5及4.7mm;塔板开孔率为9.9、12.3、13.2、14.9及15.4％; 挡沫板宽度为150、200、250、300mm;板间距为400、500、600、700及800mm;液流强度为20、30、45、60m~3/m·h;气体空塔速度为0.60—2.8m/s。测定了各有关参数对塔板压降、雾沫夹带和泄漏的影响,并对试验数据进行了关联,得出了计算塔板压降、雾沫夹带、泄漏、上限气速、下限气速及操作弹性等的关系式,以便用于网孔塔板的设计。     

混合箱塔板流体力学性能实验研究

研究开发了一种大通量高效率的混合箱塔板 ,它的非传质区仅占塔截面积的 5 %左右 ,在塔板上设计了用于提高气液传质效率的混合箱结构。在冷模试验塔内对混合箱塔板的压降、漏液、雾沫夹带以及降液管清液层高度等流体力学性能进行了试验 ,试验表明该塔板的漏液和雾沫夹带都比传统筛板有所减少 ,且通量大幅度提高     

Hydrodynamic characteristic of Conical Cap tray: Experimental studies on dry and total pressure drop,weeping and entrainment

This paper addresses an experimental investigation in the hydrodynamic behavior of a new type of cap trays called Conical Cap tray (ConCap tray). The hydrodynamics of the tray was investigated in a commercial scale air–water column with an internal diameter of 1.2 m. The experimental liquid loads were 29.9, 44.4, 60 and 74.4 (m³/h)/m of weir length and gas flow in terms of F_s in the range of 0.2–1.5 m/s (kg/m³)^0.5. The dry pressure drop, total pressure drop, weeping and entrainment for the ConCap tray and a valve tray were measured and compared. Correlations for pressure drop, weeping and entrainment of the ConCap tray were provided using regression analysis method. Standard deviations of correlations, R², are quoted. The ConCap tray was compared with a bubble cap tray using correlations. The pressure drop of the ConCap tray was less than the bubble cap and close to the valve tray. The weeping rate of the ConCap tray was less than the valve tray. Its entrainment is more than the valve tray and less than the bubble cap tray. Good turndown ratio is important characteristic of the ConCap tray which is achieved without having too much pressure drop.     

Experimental study and modeling of weeping rate in rectangular large-scale valve trays

Weeping is an important hydraulic parameter that needs to be considered for valve trays and for calculations in the distillation field. Therefore, the accurate prediction of weep rate is crucial for the optimal design of valve trays. First, the effects of gas and liquid loads and weir height on weep rate, tray pressure drop, and actual bubbling area were studied in a 1.5 m × 0.61 m cold simulator. Second, the weep modes on the valve tray were analyzed in detail. A theoretical model was then derived to calculate weeping. The model showed a clear relationship between the weep rate and the fractional bubbling area. The experimental data showed that the weir height substantially affected the orifice coefficient of the liquid passing through the valve. Finally, the relation between weir height and orifice coefficient was obtained by fitting the experimental data. The agreements were good, and the maximum deviations were approximately 25%.     

喷嘴孔VST的流体力学和传质性能研究

本文用空气-水系统,在φ1.2m的圆塔上研究了喷嘴孔垂直筛板塔盘(喷嘴孔VST)的流体力学性能,考察了各种几何因素和流体力学条件对塔板压降、漏液、气速下限、雾沫夹带和气速上限等参数的影响,获得了相应的关联式.在φ100mm的塔上,用乙醇-水系统测定了喷嘴孔VST的板效率,并与筛板搭进行了比较.     

CTST-F1复合塔板的实验研究

结合CTST和F1浮阀各自的优点,在CTST塔板的基础上组合得到了新型的CTST-F1复合塔板.以空气-水为物系,在直径为570 mm的有机玻璃冷模实验塔内,对CTST-F1复合塔板的清液层高度、板压降、雾沫夹带、漏液量等流体力学性能进行了实验测定,并与CTST塔板和F1浮阀塔板的性能进行了比较.由实验数据关联得到了复...     

Hydrodynamic characteristics of valve tray: Computational fluid dynamic simulation and experimental studies

In order to better understand the hydrodynamics of valve trays, air-water operation in an industrial scale tower with 1.2 m of diameter, consisting of two 14% valve trays, was studied. Experimental results of clear liquid height, froth height, average liquid holdup, dry pressure drop, total pressure drop, weeping and entrainment were investigated, and empirical correlations were presented. Then, a three-dimensional computational fluid dynamics (CFD) simulation in an Eulerian framework for valve tray with ANSYS CFX software was done. The drag coefficient, which was used in the CFD simulations, was calculated from the data obtained in the experiments. The simulation results were found to be in good agreement with experimental data at this industrial scale. The objective of the work was to study the extent to which experimental and CFD simulations must be used together as a prediction and design tool for industrial trays.     

立体并流板的流体力学和传质性能

新型立体连续传质液体并流塔板是将LLC-Tray与两种并流流型相结合开发而成的新型塔板。通过实验测定了新型塔板的干、湿板压降,雾沫夹带,漏液等流体力学性能和传质性能,并进行关联得到了相应公式。结果表明,新型塔板板压降较低,雾沫夹带较低,液体处理量相对LLCT提高30%。     

新型正交波纹板流体力学性能CFD模拟

介绍一种新型穿流塔板--正交波纹板。以欧拉-欧拉两相流模型为基础,建立了正交波纹板上气液两相流场的三维数学模型。CFD模型中主要考虑了气液两相间的曳力作用,相间动量传递源相采用Krishna计算方法。以清液层高度为指标,对CFD模型的可靠性进行了验证。在不同气液负荷下,对正交波纹板的压降、板上液相速度分布及塔内气液分布状况等流体力学性能进行了研究,并与淋降筛板进行对比,结果表明正交波纹板具有更高的操作弹性和更好的操作稳定性。     

Computational fluid dynamic simulation of MVG tray hydraulics

The flow pattern and hydraulics of a Mini V-Grid valve (MVG) tray is predicted by using computational fluid dynamics simulation. A 3-D CFD model in the Eulerian framework was used. The simulation results for MVG tray are compared with that of sieve tray. The sieve tray geometry and operating conditions are based on the Solari and Bell’s sieve tray [1]. The MVG tray differs from that of Solari and Bell’s sieve tray solely by the difference in design of available openings for the flow of gas. The simulation results show that the clear liquid height and the pressure drop of MVG tray are lower than that of sieve tray whereas the liquid velocity is higher and contacts of phases are good. The simulation results of sieve tray are in agreement with the experimental data of Solari and Bell [1].