Chemical Engineering & Technology, Vol.41, No.7, 1359-1367, 2018
Remixing Analysis of Four-Product Dividing-Wall Columns
Dividing-wall columns can separate multicomponent mixtures and offer large energy savings over conventional column sequences. The separation of a mixture of four alcohols was studied in a Kaibel column and a fully extended Petlyuk column or Sargent arrangement, respectively. The flow paths of intermediates are different so that the Sargent arrangement could save more energy. Remixing of intermediates is unavoidable in the Kaibel column because each of them cannot detour all around both ends of the dividing wall. The Sargent arrangement exhibits the desired detouring paths and the remixing of intermediates is alleviated but still occurs in the prefractionator and the middle column. Finally, an alternative configuration of the Sargent arrangement is proposed which presents a better thermodynamic efficiency.