The multiphase separators are generally the first and largest process equipment in an oil production platform. This primary separation step is a key element in the oil and gas production facilities in that downstream equipment, such as compressors, are completely dependent on the efficient performance of these multiphase separators. The literature on this critical unit operation, multiphase separators, abounds with macro studies and design methodologies for two‐ and three‐phase vertical and horizontal separators. There are very few studies that provide the micro details of the actual separation process. In fact, the popular classic methods for separator design, mostly due to a lack of a usable mathematical model for estimation of droplet ‘separation velocities’, do result in a conservative design and would specify extremely oversized separators. In order to reflect the current situation and address recent findings, this study will review the important literature on design and CFD simulation of multiphase separators. This review will show the benefits that CFD analyses can provide in optimising the design of new separators and solving problems with existing designs. © 2011 Canadian Society for Chemical Engineering

A realistic computational fluid dynamics (CFD) simulation of a field three-phase separator has been developed. This realistic CFD simulation provides an understanding of both the microscopic and macroscopic features of the three-phase separation phenomenon. For simulation purposes, an efficient combination of two multiphase models of the commercial CFD software, Fluent 6.3.26 (ANSYS 2006a), was implemented. The flow-distributing baffles and wire mesh demister were also modeled using the porous media model. Furthermore, a useful approach to estimating the particle size distribution in oilfield separators was developed. The simulated fluid-flow profiles are realistic and the predicted separation efficiencies are consistent with oilfield experience.

Synthesis of the optimum conventional (with non-sharp separations) distillation column sequence (DCS) is a challenging problem, in the field of chemical process design and optimization, due to its huge search space and combinatorial nature. In this paper, a novel procedure for the synthesis of optimum Conventional Distillation Column Sequence is proposed. The proposed method is based on evolutionary algorithms. The main criterion used to screen alternative DCS's is the Total Annual Cost (TAC). In order to estimate the TAC of each DCS alternative all columns that exist in the DCS are designed using short-cut methods. The performance of the proposed method and other alternatives are compared based on the results obtained for four standard benchmark problems used by researchers working in this area. Based on the results of the comparison, the proposed method outperforms the other methods and is also more flexible than other existing methods.La synthèse de la séquence de colonne de distillation (SCD) traditionnelle optimale (caractérisée par des séparations non tranchantes) représente un problème difficileà régler, dans le domaine de la conception et de l'optimisation de procédés chimiques, en raison de son immense espace de recherche et de sa nature combinatoire. Ce document propose une procédure nouvelle en vue de la synthèse de la séquence de colonne de distillation traditionnelle optimale. La méthode proposée est fondée sur des algorithmesévolutionnistes. Le critère principal utilisé pour présélectionner les autres possibilités de SCD est le coût total annuel (CTA). Pour estimer le CTA de chaque option de SCD, toutes les colonnes qui existent dans la SCD sont conçues en utilisant des méthodes abrégées. On compare ensuite le rendement de la méthode proposée et des autres possibilités en s'appuyant sur les résultats obtenus dans le cadre de quatre problèmes d'évaluation standard utilisés par les chercheurs oeuvrant dans ce domaine. En s'appuyant sur les résultats de la comparaison, la méthode proposée donne un meilleur rendement que les autres méthodes et estégalement plus souple que les autres méthodes qui existent.

Synthesis of the optimum distillation column sequence (DCS), which incorporates a huge search space composed of both conventional and complex arrangements, is a highly complicated combinatorial problem in the field of chemical process design and optimisation. In this study, a novel procedure for the synthesis of optimum DCS proposed by Boozarjomehry et al. [Boozarjomehry et al., Can. J. Chem. Eng. 87, 477–492 (2009)] is expanded to include the complex distillation arrangements. The method is based on evolutionary algorithms, and the total annual cost (TAC) is the main criterion used to screen alternatives. Efficient procedure has been proposed for encoding mechanism to include and classify various complex arrangements together with conventional distillation columns. All columns existing in each DCS alternative are designed using the most recommended short‐cut methods to estimate the TAC of the DCS. Four standard benchmark case studies are carried out to clearly demonstrate the excellent performance of the proposed method. The produced results for these problems indicate that the proposed method outperforms the other existing approaches in terms of flexibility, accuracy and comprehensiveness. © 2011 Canadian Society for Chemical Engineering

This paper provides details of comprehensive computational-fluiddynamics (CFD)-based studies performed to overcome the separation inefficiencies experienced in a large-scale three-phase separator. It will be shown that the classic design methods are too conservative and would result in oversized separators. In this study, effective CFD models are developed to estimate the phaseseparation parameters that are integrated into an algorithmic design method to specify a realistic optimum separator. The CFD simulations indicated that noticeable residence times are required for liquid droplets to penetrate through the interfaces, and liquid droplets would be entrained again from the liquid/liquid-interface vicinity by the continuous liquid phase.