Multiple feed columns

If the feed is introduced at one point along the column shell, the column is divided into an upper section, which is often called the rectifying section, and a lower section, which is often referred to as the stripping section. In multiple-feed columns and in columns from... 

Absorbers and strippers are examples of multiple feed columns. In general, in multiple feed columns, the feeds are of different compositions and/or thermal conditions and are fed to different column trays. In certain processes, multiple products are taken from the column, each from a different tray, each with a distinct composition corresponding to the draw tray fluid composition. 

Reboiler Duty for a Multiple-Feed Column (Example 9.4)... 

Levy, S.G. and M.F. Doherty, Design and synthesis of homogeneous azeotropic distillations. 4. Minimum reflux calculations for multiple feed columns. Industrial Engineering Chemistry, Fundamentals, 1986, 25(2) 269 279. 

Levy, S. G., Doherty, M. F. (1986). Design and Synthesis of Homogeneous Azeotropic Distillation. 4. Minimum Reflux Calculations for Multiple-Feed Columns. Ind. Eng. Chem. Eundam., 25,269-79. 

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