A new dry tray pressure drop model of float valve trays

Abstract

An accurate prediction of the dry pressure drop is very important for consideration of valve trays and for calculations in distillation field. Therefore, in this article, a series of hydraulic experiments were first conducted to reveal that the intermediate state during the valve opening process is closely related to the dry tray pressure drop under great valve weight. Then, a rigorous force analysis was made to show that Euler number is related only to the valve's position at the balance points for a certain valve type. Third, a new model for prediction of the dry tray pressure drop-which considers for the first time the influence of the intermediate state-was developed and then simplified for the purpose of convenient utilizations. Finally, the new model and its simplified form were tested by comparisons with the experimental results. The agreements are good, with the mean deviations being <5%.

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

“…Finally, the pressure drop produces a stepwise increase. This change is evident when the mass of the valve exceeds 32 g . Third phase: when the float valve is fully open, the pressure drop increases rapidly as the gas velocity increases.…”

“…However, the gas hole velocity at the CBP in Banik's data is considerably different from those in the work of others. Normally, the gas velocity of the balance point should be proportional to the valve weight because at the balance point, the weight of the valve is exactly equal to the force of gas acting on the valve. Although the valve weight in Banik's experiment is close to the weight used in the current experiment, the CBP data of Banik is significantly greater than the experimental values of the others.…”

“…Although the valve weight in Banik's experiment is close to the weight used in the current experiment, the CBP data of Banik is significantly greater than the experimental values of the others. Furthermore, we calculate the gas velocity at the CBP under different valve weights by using the method proposed in the literature . Then, we compare the results with the CBP value obtained from the experimental data.…”

A fundamental model for valve tray vapor cross‐flow channeling calculation

“…Wang 17 found three valve states, namely, closed, inclined, and open states, on the tray operating at dry tray, while the states of the valve with liquid existing were not similar to those operating at dry tray, and the states are listed as follows,…”

Prediction of gas–liquid interfacial area in valve trays

“…Valve trays grafted with some special structures are widely used as contactors for distillation/absorption columns because of their high tray efficiency, relatively low pressure drop, and large operation range (enhanced performance). 2 However, previous research on hydrodynamics and mass transfer has mainly focused on sieve trays, [3][4][5][6][7][8][9][10] and little attention has been centered on valve trays. [11][12][13][14][15] Therefore, high-accuracy models should be developed on the basis of theoretical research regarding the actual flow characteristics of gas-liquid in valve trays to calculate the hydraulic and mass transfer rates.…”