Analytical Relationships for the Relative Gain for Distillation Control

Jafarey, Azmi; McAvoy, Thomas J.; Douglas, James M.

doi:10.1021/i160070a015

Cited by 24 publications

(19 citation statements)

References 6 publications

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“…In the (L, V ) structure the relative gain for the ( y -L ) pairing is given by has previously been derived by Jafarey et al (1979) with the use of the constant molar overflow assumption AD = AV -AL. As no limiting assumptions were made in the derivation above, the relationship is exact for any separation process, whether the assumption of constant molar overflow holds or not and regardless of, e.g., the type of outputs used.…”

Section: Relative Gain Analysismentioning

confidence: 99%

Transformations and consistency relations of distillation control structures

Häggblom

Waller

1988

AIChE Journal

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Rigorous analytical methods for consistent modeling of control structures for multivariable processes are presented. The continuous distillation process is used to illustrate the methods, but the basic ideas, and more specifically the transformations and consistency relations derived, are valid in general.If steady-state operating data and the process gains of an arbitrary control structure are known, it is possible to calculate the process gains of any feasible control structure. A general expression relating the process gains of different control structures is derived. In general, the process gains must also satisfy certain consistency relationships which can be derived from first principles, e.g., steady-state material balances.The usefulness of the results is illustrated by control structure transformations and reconciliation of process gains, by an application to process dynamics, by synthesis of noninteracting control loops, and by derivation of analytical relationships useful in relative gain analysis.

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Section: Relative Gain Analysismentioning

confidence: 99%

Transformations and consistency relations of distillation control structures

Häggblom

Waller

1988

AIChE Journal

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“…where is the relative gain of the undecoupled system. By using approximate analytical expressions for X (Jafarey et al, 1979), it is possible to relate X to column conditions such as feed composition, feed quality, product split, relative volatility, refiux ratio, and number of column trays. In choosing which three columns to study, relative gains in the neighborhood of 2 (low s), 10 (moderate s), and 50 (high s) were sought for the case where reflux and boilup Table II.…”

Section: Columns Studiedmentioning

confidence: 99%

Feasibility of Decoupling in Conventionally Controlled Distillation Columns

Weischedel¹,

McAvoy²

1980

Ind. Eng. Chem. Fund.

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Recent steady-state work on decoupling in distillation column control has raised a number of questions about the feasibility of such control. The work of Jafarey et al. suggests that at most one-way decoupling seems to be achievable in distillation columns. The work of McAvoy further indicates that no decoupling will be possible in columns with large gains. Several other studies, both simulational and experimental, have reported the successful implementation of two-way decoupling. In this paper the results of dynamic simulations are presented which clarify this controversy. These results show that decoupling cannot be achieved in some columns.

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“…The RGA has received much attention in the recent literature. Applications of the RGA to distillation (Jafarey, McAvoy and Douglas, 1979;McAvoy 1979;Wang, 1979;Kominek and Smith, 1979;Jafarey and McAvoy, 1978;Shinskey, 1977a;Nisenfeld and Stravinski, 1968); heat exchanger networks (Nisenfeld, 1973); and several other processes (Shinskey, 1979) have been presented. The RGA has also been used to discuss decoupler sensitivity (McAvoy, 1979;Shinskey, 1977b).…”

Section: Scopementioning

confidence: 99%

Prediction of Phase Equilibria in Sour Natural Gas Systems Using the Soave-Redlich-Kwong Equation of State

Evelein¹,

Moore²

1979

Ind. Eng. Chem. Proc. Des. Dev.

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A modified Soave-Redlich-Kwong equation of state, which utilizes empirical binary interaction parameters in the mixing rules for the a and b coefficients, has been used to correlate complex phase behavior for mixtures of hydrocarbons and nonhydrocarbons. The correlation has been shown in a previous article to predict complex phase behavior associated with the systems hydrogen sulfide-water and carbon dioxide-water. This paper presents an extension of the previous study to predict complex phase behavior such as azeotropism and three phase equilibria for light hydrocarbon systems containing the nonhydrocarbons nitrogen, carbon dioxide, and hydrogen sulfide. Interaction parameters are presented for all the binaries considered.

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Analytical Relationships for the Relative Gain for Distillation Control

Cited by 24 publications

References 6 publications

Transformations and consistency relations of distillation control structures

Transformations and consistency relations of distillation control structures

Feasibility of Decoupling in Conventionally Controlled Distillation Columns

Prediction of Phase Equilibria in Sour Natural Gas Systems Using the Soave-Redlich-Kwong Equation of State

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