Bold text'Bold text'Batch distillation^[1] refers to the use of distillation, the separation of components in a system by volatilities, in batches. I.e., a mixture is separated into its component fractions, before the still is charged and the process repeated. This is in contrast with continuous distillation which allows the feedstock to be added and the distillate drawn off without interruption. Continuous distillation is a distillation process, which does not require interruption for adding raw material. ...

Batch distillation has always been an important part of the production of seasonal, uncertain or low capacity and high-purity chemicals. It is a very frequent separation process in the pharmaceutical industry and in waste-water units. A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... Separation may refer to a several different subjects: In chemistry, separation refers to the separation process. ...

Batch rectifier

The simplest and most frequently used batch distillation configuration is the batch rectifier. The batch rectifier consists of a pot (or reboiler), rectifying column, a condenser, some means of splitting off a portion of the condensed vapour (distillate) as reflux, and one or more receivers.

Image File history File links Batchrectifier4. ...

The pot is filled with liquid mixture and heated. Vapour flows upwards in the rectifying column and condenses at the top. Usually, the entire condensate is initially returned to the column as reflux. This contacting of vapour and liquid considerably improves the separation. Generally, this step is named start-up. After some time, a part of the overhead condensate is withdrawn continuously as distillate and it is accumulated in the receivers, and the other part is recycled into the column as reflux. Diagram of typical reflux apparatus. ...

Batch stripper

The other simple batch distillation configuration is the batch stripper. The batch stripper consists of the same parts as the batch rectifier. However, in this case, the pot is located at the top of a stripping column. After the start-up, during operation, the high boiling constituents are primarily separated from the system. The liquid in the pot is depleted in the high boiling constituents, and enriched in low boiling ones. This mode of batch distillation is very seldom applied to industrial processes.

Image File history File links Batchstripper3. ...

Middle vessel column

A third feasible batch column configuration is the middle vessel column. The middle vessel column consists of both a rectifying and a stripping section and the pot is located by the middle of the column.

Image File history File links Middlevessel3. ...

Feasibility

Generally the feasibility studies of the batch distillation is based on the analysis of the following maps:

• Residue Curve map,
• still path map,
• distillate path map and
• different column profile maps.

At the feasibility methods the following basic simplifying assumptions are involved: // [edit] Residue curve - Residue curve map Triangular diagrams are often used to describe the equilibrium relationships for ternary mixtures. ...

• an infinite stage number,
• an infinite reflux ratio,
• a negligible tray hold-up (excluding the decanter and the still),
• a quasi-steady state in the column,
• a constant molar overflow.

Bernot et al.^[2] used the batch distillation regions to determine the sequence of the fractions. According to Ewell and Welch ^[3], a batch distillation region gives the same fractions upon rectification of any mixture lying within it. Bernot et al.^[2] examined the still and distillate paths for the determination of the region boundaries under high number of stages and high reflux ratio, named maximal separation. Pham and Doherty in pioneering work^[4] described the structure and properties of residue curve maps for ternary heterogeneous azeotropic mixtures. In their model, the possibility of the phase separation of the vapour condensed is not taken into consideration yet. The singular points of the residue curve maps determined by this method were used to assign batch distillation regions by Rodriguez-Donis et al.^[5][6] and Skouras et al.^[7][8]. Modla et al.^[9] pointed out that this method may give misleading results for the minimal amount of entrainer. Lang and Modla^[10] the method of Pham and Doherty and suggested a new, general method for the calculation of residue curves and for the determination of batch distillation regions of heteroazeotropic distillation.

Lelkes et al.^[11] published a feasibility method for the separation of minimum boiling point azeotropes by continuously entrainer feeding batch distillation. This method has been applied for the use of a light entrainer in the batch rectifier and stripper by Lang et al. (1999)^[12] and it applied for maximum azeotropes by Lang et al.^[13]. Modla et al.^[9] extended this method for batch heteroazeotropic distillation under continuous entrainer feeding.

See also

• Azeotrope
• Azeotropic distillation
• Distillation
• Extractive distillation
• Fractional distillation
• Heteroazeotrope
• Steam distillation

This article needs more context around or a better explanation of technical details to make it more accessible to general readers and technical readers outside the specialty, without removing technical details. ... In chemistry, azeotropic distillation is any of a range of techniques used to break an azeotrope in distillation. ... Laboratory distillation set-up using a Liebig condenser, without a fractionating column. ... Extractive Distillation is defined as distillation in the presence of a miscible, high boiling, relatively non-volatile component, the solvent, that forms no azeotrope with the other components in the mixture. ... Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. ... A heteroazeotrope is an azeotrope where the vapour phase coexists with two liquid phases. ... Laboratory set-up for steam distillation Steam distillation is a special type of distillation (a separation process) for temperature sensitive materials like natural aromatic compounds. ...

References

1. ^ Kister, Henry Z. (1992). Distillation Design, 1st Edition, McGraw-Hill. ISBN 0-07-034909-6.
2. ^ ^a b Bernot C., M. Doherty, M. and M. F. Malone, Patterns of composition change in multicomponent batch distillation, Chem. Eng. Sci., 45, 1207, (1990)
3. ^ Ewell, R. H. and L. M. Welch, Rectification in Ternary Systems Containing Binary Azeotropes, Industrial Engineering Chemistry, 37, 1224,(1945)
4. ^ Pham, H. N. and M. F. Doherty, Design and synthesis of heterogeneous azeotropic distillations II. Residue curve maps, Chem. Eng. Sci., 45, 1987-1843, (1990)
5. ^ Rodriguez-Donis I, V. Gerbaud and X. Joulia, Feasibility of Heterogeneous Batch Distillation Processes, AIChE Journal, 48 (6), 1168, (2002)
6. ^ Rodriguez-Donis Y., J. A. Equijarosa, V. Gerbaud and X. Joulia, Heterogeneous Batch-extractive Distillation of Minimum Boiling Azeotropic Mixtures, AIChE Journal, 49 (12), 3074, (2003)
7. ^ Skouras S., V. Kiva and S. Skogestad, Feasible separations and entrainer selection rules for heteroazeotropic batch distillation, Chemical Engineering Science, 60, 2895, (2005)
8. ^ Skouras S., S. Skogestad and V. Kiva, Analysis and Control of Heteroazeotropic Batch Distillation, AIChE Journal, 51 (4), 1144-1157, (2005)
9. ^ ^a b Modla G., P. Lang , B. Kotai and K. Molnar, Batch Heteroazeotropic Rectification of a Low Relative Volatility Mixture under Continuous Entrainer Feeding, AIChE Journal, 49 (10), 2533, (2003)
10. ^ * Lang P. and Modla G., Generalised method for the determination of heterogeneous batch distillation regions, Chem. Eng. Sci., 61, 4262-4270, (2006)
11. ^ Lelkes Z., P. Lang, P. Moszkowicz, B. Benadda and M. Otterbein, Batch extractive distillation: the process and the operational policies, Chem. Eng. Sci., 53,1331 (1998)
12. ^ Lang, P., Lelkes Z., Otterbein M., Benadda B., Modla G. ”Feasibility studies for batch extractive distillation with a light entrainer”, Comp. Chem. Eng., 23, S93-S96, (1999).
13. ^ Lang P., G. Modla, B. Benadda and Z. Lelkes, Homoazeotropic Distillation of Maximum Azeotropes in a Batch Rectifier with Continuous Entrainer Feeding: I. Feasibility Studie, Comp. Chem. Eng., 24, 1465, (2000)

Distillation Design provides complete coverage of the design of industrial distillation columns for the petroleum refining, chemical and petrochemical plants, natural gas processing, pharmaceutical, food and alcohol distilling industries. ...

Further reading