Characteristics of push valve centrifugal tray; a novel tray with pipe type downcomer

ABSTRACT

The intention of providing this paper is to conduct an experimental investigation into the hydrodynamics of the push valve centrifugal tray, which has a new configuration, in order to retrofit the purpose of a stripper oil sweeting of Lavan oil manufacture. Experiments were performed on the commercial scale column by an air-water simulator rig. Two different pilot plants with 1.2 m and 3 m diameter have been used for experiments. Dry pressure drop, total pressure drop, and weeping data are presented on the commercial scale 1.2 m diameter column. The results compared with a sieve tray. Some correlations for the pressure drop and the weeping are presented. A pilot plant with a large diameter, 3 m, was also installed to predict the pressure drop with the exact characterization as the stripper column of Lavan oil manufacture to predict its pressure drop. The experiments were carried out in two different outlet weir heights, 0, 3 cm, and 2- and 4%-holes areas at various operating conditions. This article also introduced a new downcomer and tray design of the centrifugal tray. Experiments and industrial reports of this type of centrifugal tray show that it can be used in revamping and retrofit projects.

KEYWORDS:

• Centrifugal tray
• push valve
• hydraulics
• weeping
• dry pressure drop
• total pressure drop

Novelty statement

In this article, a novel gas liquid contactor was investigated that is introduced as Push valve centrifugal tray. Centrifugal trays can increase the capacity of the tray above the “system limit” due to the use of centrifugal force as an additional factor in the gas-liquid phase separation. The Push valve centrifugal tray which was considered in this research is recommended as high efficiency and capacity contact devices. This tray successfully installed in some actual distillation towers. The mechanism of the tray and the downcomer is presented. Additional to the using from centrifugal force, downcomer design is also effective in new tray design. A novel pipe type downcomer design is also presented which is located in the center of the tray. Experiments performed on the commercial scale column by an air-water simulator rig. Pressure drop, weeping and entrainment were measured and investigated in various weir and hole area percentages. The experiments were done at different gas and liquid flow rates.

Nomenclature

AT	=	Total hole area, m2
Fr	=	Froude number
Fs	=	F-factor = $V_S\sqrt{{\rho }_G}$, (m/s(kg/m3)0.5)
g	=	Acceleration due to gravity, m/s2
hcl	=	Clear liquid height, m
QL	=	Liquid flow, (lit/min)
Uh	=	Hole gas velocity, total gas flow rate per total hole area, m/s
WF	=	Weep flux, (m3/s)/m2
$\mathrm{\Delta }$PD	=	Dry pressure drop, cm H2O
$\mathrm{\Delta }$PT	=	Tray pressure drop, cm H2O
${\rho }_G$	=	Gas density, kg/m3
${\rho }_L$	=	Liquid density, kg/m3

Acknowledgments

Technical and financial support from Azar Energy Company is gratefully Acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author.