Numerical Analysis of Flare Gas Recovery Ejector
03 Aug 2014-
TL;DR: In this paper, the mass and momentum equations for fluid flow were solved using commercial software CFX (v14.5) for a horizontal flow, multiphase ejector used for recovery of these flared gases.
Abstract: Flaring and venting contributes significantly to greenhouse gas emissions and environmental pollution in the upstream oil and gas industry. Present work focuses on a horizontal flow, multiphase ejector used for recovery of these flared gases. The ejector typically handles these gases being entrained by high pressure well head fluid and a comprehensive understanding is necessary to design and operate such recovery system. A CFD based analysis of the flow through the ejector has been reported in this paper. The flow domain was meshed and the mass and momentum equations for fluid flow were solved using commercial software CFX (v14.5). Euler-Euler multiphase approach was used to model different phases. The entrainment behavior of the ejector was investigated and compared for different fluid flow conditions. It was observed that for a fixed primary fluid flow rate, the entrained or secondary flow rate decreased linearly with an increase in pressure difference between exit and suction pressure. The higher was primary flow rate, the greater was the suction created ahead of the primary nozzle and greater was the amount of energy added to the entrained fluid.Copyright © 2014 by ASME
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TL;DR: In this article, the relative motion correlations for dispersed two-phase flows of bubbles, drops, and particles were developed from simple similarity criteria and a mixture viscosity model, and satisfactory agreements were obtained at wide ranges of the particle concentration and Reynolds number.
Abstract: Drag coefficient and relative motion correlations for dispersed two-phase flows of bubbles, drops, and particles were developed from simple similarity criteria and a mixture viscosity model. The results are compared with a number of experimental data, and satisfactory agreements are obtained at wide ranges of the particle concentration and Reynolds number. Characteristics differences between fluid particle systems and solid particle systems at higher Reynolds numbers or at higher concentration regimes were successfully predicted by the model. Results showed that the drag law in various dispersed two-phase flows could be put on a general and unified base by the present method.
1,685 citations
TL;DR: In this paper, a theory is proposed which describes the transfer process of momentum and heat in a two-phase bubble flow in channels, and the eddy diffusivity to express the turbulent structure of the liquid phase is subdivided into the two components, one for the inherent wall turbulence independent of bubble agitation and the other for the additional turbulence caused by bubbles.
489 citations
TL;DR: In this paper, the authors studied the effect of the angle of converging section on the entrainment rate of the secondary fluid in an ejector with a given projection ratio (L TN / D T ).
94 citations
TL;DR: In this paper, the authors used a computational fluid dynamics (CFD) model to understand the hydrodynamic characteristics with reference to the ejector geometry and provided a basis for quantifying the effects of operating conditions on ejector performance.
81 citations
TL;DR: A semi-empirical model has been developed to predict the liquid entrainment rate taking into account, (1) the compressible nature of air, (2) pressure drop for two phase flow and (3) losses due to changes in cross sectional area.
Abstract: In the present work, experimental investigations have been carried out on ejectors employing gas (air) as a motive fluid and liquid (water) as the entrained fluid. A semi-empirical model has been developed to predict the liquid entrainment rate taking into account, (1) the compressible nature of air, (2) pressure drop for two phase flow and (3) losses due to changes in cross sectional area. The effects of gas velocity, liquid level in the suction chamber, nozzle diameter, throat height and throat diameter on the liquid entrainment, entrainment ratio and pressure drop have been investigated. It has been observed that the liquid entrainment rate increases with an increase in the liquid level in the suction chamber. It was also found to increase with an increase in the gas velocity. The ratio of throat cross-sectional area to the nozzle cross-sectional area (area ratio) was found to be a critical parameter. The results have been explained on the basis of pressure profiles. The values of liquid entrainment rate predicted from the semi-empirical model were found to be in good agreement with the experimental measurements.
17 citations