Application of a fully thermally coupled distillation column for fractionation process in naphtha reforming plant

Naphtha reformate is extracted for aromatic compounds and the aromatics are separated into benzene, toluene and xylene in sequence. This separation is conducted using a series of binary-like columns. In this study, the first two columns of the separation process are replaced with a fully thermally coupled distillation column (FTCDC) also known as the Petlyuk column. Though feed of the process contains 18 components, the FTCDC developed for the separation of a ternary system is effectively implemented in the industrial-scale application. A structural design to determine the optimum structure of the column from the minimum tray configuration is utilized, and the minimum tray configuration is found from the stage-to-stage computation with ideal tray efficiency in equilibrium condition. The operating condition to yield a given set of product specifications is found from the HYSYS simulation. The performance of the FTCDC is compared with a conventional two-column process to indicate an energy saving of 13% and the investment cost reduction of 4%.