Adaptability And Thermodynamic Efficiency Of Thermally Coupled Distillation

Distillation, which is presently being applied to the industrial level in crude oil refine, chemical engineering and natural gas processing, is one of the most widely used separation technology in present industry and almost the largest energy consumption unit operation. Therefore, it is very important to have the investigation of the energy saving in the distillation process under the circumstance of energy source deficiency.Thermally coupled distillation column consists of two towers, and it is a kind of complex columns. It has much less irreversible energy loss and higher Thermodynamic Efficiency in distillation process because of the reversible mixed property. It both conserves energy and saves the equipment investment, but also has other merits, thus it has the extremely attractive prospects for development. Therefore, it attracts many eyes from academic and industry circles.Thermally coupled distillation columns can reduce energy consumption and capital investment comparing to conventional distillation consequences for separation of ternary and multi components mixtures with the application of Aspen Plus software, rigorous simulations were firstly performed to the thermally coupled distillation columns for ternary hydrocarbon mixture separation, focusing on how middle component fractional recovery influences overall expense under the conditions of different feed compositions and diverse relative volatilities.Thermodynamic efficiency calculations and energy requirements have been performed for the separation of ternary mixtures of hydrocarbons in both 2 kinds of conventional and 3 kinds of thermally coupled distillation sequences.When ternary mixtures were considered, energy savings achieved in the thermally coupled distillation sequences were between 10 and 50% in comparison to the two conventional distillation sequences. Regarding thermodynamic efficiency, thermally coupled distillation sequences presented the highest values in almost all of the cases considered. When the Ease of Separation Index is around 1 or less than 1, When the Ease of Separation Index is around 1 or less than 1, thermally coupled distillation columns are better. And when the middle component composition is higher, thermally coupled distillation columns is better.