A solution of Rachford-Rice equations for multiphase systems

Leibovici, Claude; Neoschil, Jean

doi:10.1016/0378-3812(95)02797-i

Cited by 71 publications

(58 citation statements)

References 3 publications

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“…1,2 On the other hand, three-phase split calculations are not yet mature enough for implementation in commercial compositional reservoir simulators, despite a large number of publications on the subject. [3][4][5][6] Michelsen and Møllerup 7 point out…”

Section: Introductionmentioning

confidence: 99%

Efficient and robust three‐phase split computations

2010

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The combination of successive substitution and the Newton method provides a robust and efficient algorithm to solve the nonlinear isofugacity and mass balance equations for two-phase split computations. The two-phase Rachford-Rice equation may sometimes introduce complexity, but the Newton and bisection methods provide a robust solution algorithm. For three-phase split calculations, the literature shows that the computed three-phase region is smaller than measured data indicate. We suggest that an improved solution algorithm for the three-phase Rachford-Rice equations can address the problem. Our proposal is to use a two-dimensional bisection method to provide good initial guesses for the Newton algorithm used to solve the three-phase RachfordRice equations. In this work, we present examples of various degree of complexity to demonstrate powerful features of the combined bisection-Newton method in threephase split calculations. To the best of our knowledge, the use of the bisection method in two variables has not been used to solve the three-phase Rachford-Rice equations in the past. V V C 2010 American Institute of Chemical Engineers AIChE J, 57: [2555][2556][2557][2558][2559][2560][2561][2562][2563][2564][2565] 2011

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Section: Introductionmentioning

confidence: 99%

Efficient and robust three‐phase split computations

2010

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“…[25] are used; in the case of a too early switch the code reverts to SSI. For SSI, RR equation is solved using the method of Leibovici and Neoschil [11]; for NR iterations, V is an independent variable and the RR equation is not directly solved (it is one of the error equations). No attempts were made to use convergence acceleration procedures such as dominant eigenvalue method, because they are risky for negative flashes, mainly near the CL [1].…”

Section: Convergence Locusmentioning

confidence: 99%

“…The negative flash is also important for flash calculations at different specifications (other than pressure and temperature, see Michelsen [6,7]), and for pseudo-component delumping [8][9][10]. The negative flash was extended to multiphase equilibrium calculations by Leibovici and Neoschil [11]. One of the most important negative flash applications and maybe the most important application of the convergence pressure concept is the calculation of the minimum miscibility pressure (MMP) in multicomponent hydrocarbon/injected gas systems [12,13] in the case of a pure condensing or vaporizing drive.…”

Section: Introductionmentioning

confidence: 99%

Calculation of convergence pressure/temperature and stability test limit loci of mixtures with cubic equations of state

Nichita¹,

Broseta²,

Montel³

2007

Fluid Phase Equilibria

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“…The algorithm of resolution of the Rachford-Rice equations applied to multiphase systems proposed by Leibovici and Neoschil [70] can be used in the phase equilibrium calculations. It is a very stable algorithm because of its continuity across phase boundaries leading to non-physical phase amounts for the unstable phases.…”

Section: Multiphase Flash Calculationsmentioning

confidence: 99%

“…The number of solid phases is a product of the multiphase flash calculation resulting from the instability caused by the non-ideality of the solid solutions. With this approach if p phases are present and the liquid phase is used as reference phase the phase fractions, ψ i , are obtained from the solution of a systems of (p-1) equations [70,71]. Given a fluid with a composition z i , for a generic phase k ( ) ( )…”

Section: Multiphase Flash Calculationsmentioning

confidence: 99%

Modelling Phase Equilibria in Systems with Organic Solid Solutions

Coutinho¹,

Pauly²,

Daridon³

2004

Computer Aided Chemical Engineering

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INTRODUCTIONThe formation of alloys of inorganic compounds has been known for centuries, yet it is not only on metallurgy and ceramics that metals and inorganic salts in general form mixed crystals. Reports on the formation of alloys, or solid solutions, of organic compounds, although still rare, have been appearing regularly in the last few years for aromatic compounds, such as substituted benzenes and naphtalenes [1][2][3], pyrene and anthracene [4][5][6], for carbohydrates [7], terpenes [8], neopentane derivatives [9-10] and fulerenes, besides solid solutions of C 60 with C 70 [11][12] solid solutions of C 60 in sulphur have been reported [13]. Nevertheless it is among the molecules with long n-alkyl chains such as n-alcohols Although the materials based on n-alkane alloys have been used for long as candles, waterproof coatings, pharmaceutical and cosmetics, and in spite of paraffin waxes being a valuable by-product of petroleum refining, the research on n-alkane solid solutions has been mainly prompted by its dark side: The damages and losses caused by wax precipitation from petroleum fluids. Every year wax deposition costs billions of dollars in preventive maintenance, remediation of pipeline blockages and losses of production [22,23]. Better computer models can help anticipate the problems allowing for preventive actions, optimization of actions and avoid losses by shutting down of production or by accident.The presentation of this chapter will focus on the prediction of the wax precipitation from petroleum fluids both at high pressures, in reservoir conditions, or at low pressures, as stock tank oil or fuels. In the final section the application of the model proposed to other systems of organic solid solutions will be discussed.

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A solution of Rachford-Rice equations for multiphase systems

Cited by 71 publications

References 3 publications

Efficient and robust three‐phase split computations

Efficient and robust three‐phase split computations

Calculation of convergence pressure/temperature and stability test limit loci of mixtures with cubic equations of state

Modelling Phase Equilibria in Systems with Organic Solid Solutions

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