Chemical Engineering and Processing 64 (2013) 17–23 Contents lists available at SciVerse ScienceDirect Chemical Engineering and Processing: Process Intensification jo u rn al hom epage: www.elsevier.com/locate/cep Hydrodynamic characteristic of Conical Cap tray: Experimental studies on dry and total pressure drop, weeping and entrainment Taleb Zarei, Rahbar Rahimi ∗ , Ali Zarei, Mortaza Zivdar Department of Chemical Engineering, University of Sistan and Baluchestan, Zahedan 98164-161, Iran a r t i c l e i n f o Article history: Received 26 April 2012 Received in revised form 24 September 2012 Accepted 25 November 2012 Available online 12 December 2012 Keywords: Conical Cap tray Hydrodynamics Pressure drop Weeping Entrainment a b s t r a c t 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 commer- cial 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 (m 3 /h)/m of weir length and gas flow in terms of F s in the range of 0.2–1.5 m/s (kg/m 3 ) 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 Con- Cap tray were provided using regression analysis method. Standard deviations of correlations, R 2 , 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. © 2012 Elsevier B.V. All rights reserved. 1. Introduction In recent years, many efforts have been made to improve trays of distillation columns to obtain better efficiency, capacity and lower pressure drop that encountered in commercial operation. Distil- lation has become the target of efficiency increasing efforts, by improving the equipment, or by combining it in an effective way with other separations or reactions. The ultimate developments in these respect are centrifugal devices [1]. Examples are Swirltube, ConSep [2–4] and Ultra-Frac [5,6] trays. Bravo and Kusters [2] men- tioned that centrifugal trays are the new millennium technology for tray design. In these ultra-capacity trays, vapor and liquid travel co-currently in the contacting modules. Therefore, there is not liq- uid concentration gradient along with the flow of liquid on the tray deck and contact time is usually short and most of these high capacity trays cannot deliver the same efficiency as well-design conventional trays such as sieve, valve and bubble cap trays [7]. In this paper, we introduce geometry of our newly designed tray referred to as Conical Cap tray or abbreviated as ConCap tray that has a special designed conical cap. That resembles a bubble cap tray. Its merits were explained by comparing its hydrodynamics behavior with a valve and a bubble cap trays. ∗ Corresponding author. Tel.: +98 5412440418. E-mail address: rahimi@hamoon.usb.ac.ir (R. Rahimi). Sieve and valve trays and their modifications [8,9] represent the most commonly used trays for gas–liquid contacting devices, so in this research the hydraulic of the ConCap tray was compared with the experimental study on the valve tray. Because of similarity between the ConCap tray and the bubble cap tray in the gas pass way, the round bell shaped bubble cap correlation data [10,11] were used for comparing hydrodynamics of the ConCap and bubble cap trays. Many studies of hydraulics and efficiency have been conducted on sieve and valve trays in academic and industrial laboratories and most of the studies on proprietary trays have been conducted by Fractionation Research Inc. (FRI). The industrial results are in most cases unavailable. Further, most academic distillation researches are done on small diameter columns while the size of the equip- ment is an important parameter when data relevant to equipment capacity are to be considered [12]. Hydraulic performance data measured using air/water and air/isoparaffins have provided the basis for the design of thousands of columns [13]. In this study, the design of pilot plant in com- mercial scale for hydraulic experimentation is presented. Pressure drop, weeping, uniformity of weeping and entrainment were mea- sured and investigated. The experiments were done at different gas and liquid flow rates. The dry and total pressure drop, entrainment and weeping data were obtained for commercial-scale ConCap and valve trays. The hydrodynamic results of the ConCap tray were com- pared with the valve and bubble cap trays. The results of the ConCap 0255-2701/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.cep.2012.11.010