Distillation dividing wall columns

Kaibel, B. (2007). Distillation - dividing wall columns. Encyclopedia of Separation Science, pp. 1-9. Elsevier, Oxford. 

Distillation. There is a large inventory of boiling liquid, sometimes under pressure, in a distillation column, both in the base and held up in the column. If a sequence of columns is involved, then, as discussed in Chap. 5, the sequence can be chosen to minimize the inventory of hazardous material. If all materials are equally hazardous, then choosing the sequence that tends to minimize the flow rate of nonkey components also will tend to minimize the inventory. Use of the dividing-wall column shown in Fig. 5.17c will reduce considerably the inventory relative to two simple columns. Dividing-wall columns are inherently safer than conventional arrangements because they lower not only the inventory but also the number of items of equipment and hence lower the potential for leaks. 

If complex distillation columns are being considered, then these also can bring about significant reductions in capital cost. The dividing-wall column shown in Fig. 5.17 not only requires typically 20 to 30 percent less energy than a conventional arrangement but also can be typically 30 percent lower in capital cost than a conventional two-column arrangement. ... 

M. Serra, M. Perrier, A. Espuna, L. Puigjaner, 2000, Study of the Divided Wall Column Controlabillity Influenee of the Design and Operation, Comput. Chem. Eng., vol. 24, p. 901 C. Tryantafillou, R. Smith, 1992, The Design and Optimisation of Fully Thermally Coupled Distillation Columns, TransIChemE, part A, Chem. Eng. Res. Des., vol. 70(A5), p. 118... 

Another approach intensifies distillation by combining two columns into one, a so-called dividing wall column (Figure 3.8). This arrangement obviates a second separate column and its evaporator and condenser. The unit features a vertical wall in the middle part of the column, creating a feed and draw-off section in this part of the column. The dividing wall, which is designed to be gas- and liquid-sealed, permits... 

The bottoms stream from this column is stripped free of butenes in the top half of the rectifier (2). A side stream containing butadiene and a small amount of acetylenic compounds (C3 and C -acetylenes) is withdrawn from the rectifier and fed into the after-washer, the second extractive distillation column (3). In recent designs, the rectifier (2) and after-washer are combined using a divided wall column. 

Amminudin, K.A. and Smith, R. (2001) Design and optimization of fully thermally coupled distillation columns. Part 2 application of dividing wall columns in retrofit. Chemical Engineering Research and Design, 79, 716-724. 

Dejanovic, I., Matijasevic, LJ. and Olujic, i. (2010) Dividing wall column—A breakthrough towards sustainable distilling. Chemical Engineering and Processing, 49,559-580. 

Ennenbach, R, Kolbe, B. and Ranke, U. (2000) Divided-wall columns—a novel distillation concept... 

Eirico, M., Tola, G., Rong, B.G. et al. (2009) Energy saving and capital cost evaluation in distillation column sequences with a divided wall column. Chemical Engineering Research and Design, 87, 1649-1657. 

Lee, S.H., Shamsuzzoha, M., Han, M. et al. (2011a) Study of structural characteristics of a divided wall column using the sloppy distillation arrangement. Korean Journal of Chemical Engineering, 28, 348-356. 

Long, N.V.D. and Lee, M. (2014) Review of retrofitting distillation columns using thermally coupled distillation sequences and dividing wall columns to improve energy efficiency. Journal of Chemical Engineering of Japan, 47, 87-108. 

Slade, B., Stober, B. and Simpson, D. (2006) Dividing wall column revamp optimizes mixed xylenes production. Distillation Absorption IChemE., Symposium Series, 152, 1-10. 

The divided-wall column splits the middle section of a single vessel into two areas by inserting a vertical wall in the vessel at an appropriate position, not necessarily at the diameter. Feed is introduced into the prefractionator side of the wall. A sidestream is removed from the other side. The sidestream is mostly the intermediate boiling component of the ternary mixture. The lightest component goes overhead in the distillate product, and the heaviest component goes out in the bottoms product. 

In this chapter, we discuss both the steady-state design and the dynamic control of divided-wall columns. Aspen simulation tools are used. The industrially important ternary separation of benzene, toluene, and o-xylene (BTX) is used as anumerical example. The normal boiling points of these three components are 353, 385, and 419 K, respectively, so the separation is a fairly easy one with relative volatilities aa/ax/ax of about 1. I2.2I. The feed conditions are a flow rate of 3600 kmol/h, a composition of 30/30/40 mol% B/T/X, and a temperature of 358 K. Chao-Seader physical properties are used in the Aspen simulations. Product purities are 99mol%. All simulations use rigorous distillation column models in Aspen Plus. 

A. A. Kiss and D. Suszwalak, Enhanced bioethanol dehydration by extractive and azeotropic distillation in dividing-wall columns, Sep. Pur if. Technol. 86, 70 (2012). 

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