This work presents a three-dimensional computational fluid dynamics (CFD) study of a two-phase flow field in a gas-liquid cylindrical cyclone (GLCC) using CFX4.3™, a commercial code based on the finite volume method. The numerical analysis was made for air-water mixtures at near atmospheric conditions, while both liquid and gas flow rates were changed. The two-phase flow behavior is modeled using an Eulerian-Eulerian approach, considering both phases as an interpenetrating continuum. This method computed the inter-phase phenomena by including a source term in the momentum equation to consider the drag between the liquid and gas phases. The gas phase is modeled as a bimodal bubble size distribution to allow for the presence of free- and entrapment gas, simultaneously. The results (free surface shape and liquid angular velocity) show a reasonable match with experimental data. The CFD technique here proposed demonstrates to satisfactorily reproduce angular velocities of the phases and their spatial distribution inside the GLCC. Computed results also proved to be useful in forecasting bubble and droplet trajectories, from which gas carry under (GCU) and liquid carry over might be estimated. Nevertheless, moderate differences found between the computed GCU and experimental measurements suggest that new adjustments may be done to the numerical model to improve its accuracy.

A modified mechanistic model is formulated to predict the pressure drop in horizontal slug flow for two-phase flow (viscous liquid and air). The model is evaluated by using accurate PDVSA INTEVEP experimental data for liquid with viscosity of 480 cP. A comparison between the modified model and experimental data shows that the absolute average relative error in pressure drop prediction is less than 6%. Introduction Venezuela has the world largest heavy oil reserves. PDVSA has launched several projects to develop the technology for optimum exploitation and production schemes. Special attention have been focused on multiphase flow along the production system, which includes horizontal & multilateral wells, vertical wells (tubing & annular flow), pipelines and production networks. Multiphase flow is characterized for the existence of flow patterns. There are different types of them, where the most common one is called slug flow, see Fig 1. Therefore, proper production system design requires of reliable pressure drop models for slug flow. Current pressure drop models for slug flow, have been developed and validated for low viscosity oils. Fluid properties affect the slug flow characteristics as well as the behavior of the pressure losses. Available pressure drop models estimate the pressure gradient with average errors about 30% as can be seen in Fig 2. This uncertainty might affect CAPEX and OPEX up to 10%. The interest of this work is to develop a rigorous pressure drop model that can be applied for both light and heavy oils. The model should be validated initially with lab data and then with field data. Due to the lack of high quality laboratory data for pressure drop in heavy oils, PDVSA INTEVEP built a multiphase production laboratory. The experimental facility and the slug flow model will be described next. Experimental Setup Test facility description Experiments were carried out in a 2-in test loop facility at PDVSA INTEVEP. Lube oil (480 cP) and air were testing fluids.

This work presents a three-dimensional CFD study of a two-phase flow field in a Gas-Liquid Cylindrical Cyclone (GLCC) using CFX4.3™, a commercial code based on the finite volume method. The numerical analysis was made for air-water mixtures at near atmospheric conditions, while both liquid and gas flow rates were changed. The two-phase flow behavior is modeled using an Eulerian-Eulerian approach, considering both phases as an interpenetrating continuum. This method computed the inter-phase phenomena by including a source term in the momentum equation to consider the drag between the liquid and gas phases. The gas phase is modeled as a bimodal bubble size distribution to allow for the presence of free- and entrapment gas, simultaneously. The results (free surface shape and liquid angular velocity) show a reasonable match with experimental data. The CFD technique here proposed, demonstrates to satisfactorily reproduce angular velocities of the phases and their spatial distribution inside the GLCC. Computed results also proved to be useful in forecasting bubble and droplet trajectories, from which gas carry under (GCU) and liquid carry over (LCO) might be estimated. Nevertheless, moderate differences found between the computed GCU and experimental measurements, suggests that new adjustments may be done to the numerical model to improve its accuracy.

The liquid-vapor and solld-llquid-vapor equilibria of the binary systems ethylene-n-elcosane and ethylene-n-dotrlacontane are studied, with particular attention being paid to the critical end points of the n-paraffin-rich branches of the S-L-V loci. Pressure, temperature, liquid-phase composition, and molar volume are reported. These data are discussed In comparison with existing ethylene-hydrocarbon phase equilibria data, taken by us and other investigators, from both a systematic and correlational viewpoint.

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