齿边浮阀塔板水力学模型

基于齿边浮阀塔板流体力学性能实验数据开发了水力学模型。介绍了齿边浮阀的结构特点,该浮阀塔板克服了F1型浮阀塔板的许多缺点,例如液面梯度较大,返混程度比较高,浮阀易旋转、磨损、脱落等。然后根据其所做的水力学性能研究的实验数据进行回归得到水力学模型,包括干板压降、湿板压降、雾沫夹带、漏液,并对模型计算的数据和实验数据进行了比较。结果表明:塔板压降的误差比较小,雾沫夹带和漏液的误差相对大一点,但该模型能较好地反映出齿边浮阀塔板的水力学性能,可以为以后水力学计算提供参考。     

新型浮阀塔板研究进展

介绍了在传统圆盘形浮阀、条形浮阀及固定阀塔板基础上研究开发的新型浮阀塔板。分析了各种新型浮阀塔板的结构特点、流体力学性能和传质性能,并比较了各种新型浮阀塔板的优缺点,概述了在不同生产工况下浮阀塔板的选择。     

组合导向浮阀塔板的雾沫夹带实验及CFD模拟

对组合导向浮阀塔板进行了水力学实验，测定了2块直径1m、不同浮阀排布的组合导向浮阀塔板的雾沫夹带和相关水力学数据。根据实验塔板的结构和尺寸参数建立几何模型，采用Fluent 6.3.26软件对板上气液两相流动进行CFD模拟，考察了塔板上的气液两相流动状况。清液层高度和雾沫夹带的模拟结果与实验结果吻合较好，验证了模拟的准确性。对两块不同浮阀排布的组合导向浮阀塔板的雾沫夹带和板上液体反向流进行了分析，结果表明在适当位置用导向能力更强的梯形浮阀代替矩形浮阀可有效降低雾沫夹带率和液体反向流比例，雾沫夹带率的实验值和模拟值分别降低了13.4%和10.6%，液体反向流比例降低了12.8%。研究结果表明，通过CFD模拟可望指导两种浮阀的合理排布和塔板的优化设计。     

国内浮阀塔板的现状及发展

针对国内石油化工企业大部分仍采用旧式浮阀塔板,存在板效率低的情况,综述了常用的几种浮阀塔板:F1型浮阀、L1条型浮阀、T形条阀、HTV船型浮阀及三角浮阀的结构、性能,国内使用情况,对几种类型进行比较。指出T形条阀和HTV船型浮阀塔板是值得推广应用的两种塔板,未经工业应用的三角浮阀塔板具有较好的发展前途。     

全周向通气条形导向浮阀塔板流体力学性能研究

应用空气-水系统,在直径1 200 mm的冷模塔内对上海唐华化工的新型条形浮阀塔板———全周向通气条形导向浮阀塔板进行了流体力学性能测量,并与F1浮阀进行了对比。实验表明,新型条形导向浮阀塔板的流体力学性能有了明显改善,相同条件下板压降比F1浮阀低20%左右,雾沫夹带较F1型浮阀小10%左右,漏液量较F1型浮阀稍大。     

组合导向浮阀塔板在常压塔的应用

新型组合导向浮阀塔板是在导向浮阀塔板基础上以矩形导向和梯形导向浮阀按照一定比例配比组合而成，在提高轻油收率方面效果明显。常压分馏塔通过采用新型组合导向浮阀塔板替代原有JF型浮阀塔板，使常压塔收率提高1．5％左右。     

波纹导向浮阀塔板的雾沫夹带研究

在直径1 000 mm、高6 m中试规模的不锈钢圆形塔内,采用空气-水物系进行冷模实验,对波纹导向浮阀塔板的雾沫夹带性能进行了研究,考察了液流强度、出口堰高等因素对其雾沫夹带的影响,并比较了带孔、不带孔波纹导向浮阀和F1型浮阀的雾沫夹带分率。结果表明,波纹导向浮阀塔板在不同的液流强度下都具备较好的操作弹性;带导向孔的波纹浮阀塔板的雾沫夹带率较无导向孔低,证明了浮阀上方开导向孔的优越性;在较大的空塔动能因子下,带导向孔波纹浮阀塔板的抗雾沫夹带性能明显优于F1型浮阀。     

导向梯形浮阀的升程对其塔板性能影响

为使导向梯形浮阀在工业应用时,选取浮阀升程有可靠的参考数据,针对导向梯形浮阀的升程这一结构参数进行试验研究。采用空气-水系统,在500 mm×500 mm的方形塔内,对不同浮阀的升程对导向梯形浮阀塔板的流体力学进行了实验研究,测定了塔板压降、泄漏和雾沫夹带。并应用空气-水-CO2系统,在不同的升程下测定了斜孔梯形浮阀塔板的传质效率。实验结果表明,导向梯形浮阀塔板的升程对其流体力学和传质性能有显著的影响,并在确定的条件下有最佳值。     

组合导向浮阀塔板的板效率研究

在直径为0.75 m的不锈钢塔内,以正庚烷-环己烷为物系,常压全回流条件下,进行了组合导向浮阀传质效率的研究,测试了该塔板的气、液相默弗里板效率和全塔效率,并和F1型浮阀塔板的全塔效率进行了对比。采用AIChE与Chen,Chuang 2种传质模型计算了组合导向浮阀塔板的点效率值。研究了AIChE与Molnar 2种计算涡流扩散系数的方法对默弗里板效率的影响。实验结果表明:在正常操作范围内组合导向浮阀塔板全塔效率高于F1型浮阀塔板。经比较实验值与模型值,发现采用Chen,Chuang预测点效率和Molnar方法计算涡流扩散系数所估计的默弗里板效率偏差在11%内。     

复合条形细分浮阀流体力学性能研究

采用空气-水系统在1200 mm的冷模塔内对一种新型浮阀塔板———复合条形细分浮阀(CRSV)的流体力学性能进行了实验研究。测定了塔板压降、塔板泄漏、塔板雾沫夹带等性能,并且在相同的实验条件下与标准的F1型浮阀进行了对比实验。实验结果表明:复合条形细分浮阀塔板比标准的F1型浮阀塔板压降可低10%—20%,雾沫夹带量低20%,低气速下泄漏量低15%—30%,这表明复合条形细分浮阀具有更好的操作弹性。     

齿边浮阀塔内气相流场的数值模拟和分析

A three-dimensional computational fluid dynamics （CFD） model for gas flow through a serrated valve tray was presented. The flow field, as well as the dry-pressure drop of the valve under the full-opening condition was simulated based on the proposed model by using FLUENT 6.0 software. Compared with the values of dry-pressure dro.p in different turbulent models, the.simulated.results using RNG κ-ε model are in reasonable agreement with experimental data, indicating that RNG κ-ε model is suitable in simulating gas flow through the serrated valve tray. Then the CFD model combining RNG κ-ε model was used to study the three-dimensional gas flow through the considered serrated valve tray. The simulated results showed that various eddies existed on the serrated valve tray, and both the eddy and the non-eddy areas were nearly equal. The existence of addendum can decrease the eddy area caused by gas passing through the lateral outlet slots. The size of eddies can be reduced by optimizing the distance between valves.     

Predicting valve tray efficiency

Existing literature models for predicting the mass transfer efficiencies of binary hydrocarbon, distillation columns employing moving valve trays are evaluated. Only four models for predicting valve tray efficiencies exist in the open literature. All of these models use data from valve trays. The last theoretical model was published in 1972, 42 years ago. By comparison, sieve tray efficiency models are numerous and recent. Sieve tray models were developed from large databases. There are no valve tray equivalents to the fundamental mechanistic models available for sieve trays. Despite the differences between valve and sieve trays, many of the phenomena on sieve and valve trays are similar. Consequently, sieve tray models can be employed to provide estimates for valve trays. In this work, using public FRI data on round moving valves, the performance of the Chen and Chuang sieve tray mechanistic model is compared to the performance of four valve tray models. It appears that, in the absence of fundamental (and qualified) valve tray models, the sieve tray models present a potential alternative for valve tray efficiency predictions.     

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%.     

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.     

浮阀塔板雾沫夹带的不均匀分布及其对传质效率的影响

本文给出了塔板雾沫夹带沿液流方向有不均匀分布时计算表观效率的模型并讨论了不同条件下的影响,当以雾沫夹带分布函数的一阶矩作为不均匀的特征参数时,获得了满意结果.文中还给出了F-1浮阀塔板上不均匀分布的实验关联式.     

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...     

Prediction of gas–liquid interfacial area in valve trays

An accurate prediction of gas–liquid interfacial area is very important for the design and optimization of column trays. However, the difference of the gas–liquid flow regimes operating at different scale trays significantly affect the interfacial area calculation. Therefore, in this study, an interfacial area model operating at small column was established using the Kolmogorov's isotropic turbulence hypothesis. According to the analyzes of the gas–liquid flow phenomena of different scale columns, an assumption that the similarity principle of flow characteristics of gas–liquid in full contact was proposed. Moreover, a new model that can be used to predict the gas–liquid interfacial area of a large column with exiting the nonideal flow was obtained through the extension of the small tray interfacial area model based on this principle. Finally, the new model was tested by comparisons with the experimental results of references. The prediction accuracy significantly improved with the maximum deviation of approximately 40%. © 2015 American Institute of Chemical Engineers AIChE J, 62: 905–915, 2016     

锯齿边窄条阀塔板流体力学和传质性能实验研究

详细分析了锯齿边窄条阀的锯齿边对传质性能的影响和锯齿边窄条阀的结构特点。在1000 mm×350 mm规格的实验塔中,以典型的水-空气冷模实验系统,对锯齿边窄条阀STV75塔盘和F1圆形浮阀塔盘进行了对比实验,测定了多种气液负荷下的压降、雾沫夹带、泄漏量等流体力学性能。利用氧解吸法,测定了塔板传质效率。实验结果和工业应用表明,在相同条件下,锯齿边窄条浮阀塔板比F1圆形浮阀塔板的板效率提高10%—20%、板压降降低100 Pa以上,雾沫夹带与泄漏与F1阀相当,是一种综合性能优良的新型浮阀。     

半椭圆固定阀塔板性能研究

应用空气–富氧水系统,在直径1 200 mm不锈钢塔内,对半椭圆固定阀塔板进行了实验室研究,研究结果表明:半椭圆固定阀塔板的压降略高于筛孔塔板,比F1浮阀塔板小得多,雾沫夹带率低于筛孔塔板和F1浮阀塔板,泄漏率比筛孔塔板低,比F1浮阀塔板高,传质效率优于筛孔塔板和F1浮阀塔板,是一种综合性能优异的塔板。     

Theoretical and experimental investigation on the characteristics of fly‐ash scrubbing in a fixed valve tray column

The goal of this study is to evaluate the performance of a fixed valve tray column designed to remove fly‐ash particles. A series of experiments were carried out at room temperature to demonstrate the collection efficiency of a fixed valve tray column at different gas and liquid superficial velocities. The fly‐ash particles removal characteristics of the fixed valve tray column were evaluated by measuring variations of concentration and size distribution of particles in the outlet. The mechanism of particle removal in this turbulent dispersion system was theoretically analyzed on the basis of diffusion, interception, sedimentation and impaction, and a model was proposed to predict the collection efficiency. The results show that the simulation results agree well with the experimental data. In contrast to most of the conventional models, the present model is capable of evaluating the effects of bubble hydrodynamics, system property, and operation conditions on the collection efficiency. The model is expected to guide effectively the design and operation of valve tray washing columns, which is widely applied nowadays. © 2012 American Institute of Chemical Engineers AIChE J, 59: 2168–2178, 2013