Characteristics of energy savings in an ideal heat-integrated distillation column (HIDiC)

Distillation columns are major energy consumers in the chemical and petrochemical industries. In order to reduce energy consumption, considerable studies have been carried out and many distillation columns have been proposed. A heat-integrated distillation column (HIDiC) is constructed in such a manner that its rectifying and stripping sections are separated, while connected through a compressor and a throttling valve. Separation is benefited by heat integration between the two sections. To provide the driving forces for heat transfers from the rectifying to the stripping sections, the former must be operated at a higher pressure than the latter. The HIDiC is expected to be more energy efficient than conventional columns, while at the expenses of some energy to raise up the pressure of the rectifying section. In this paper, it is shown by thermodynamical consideration that the HIDiC has high potential of energy loss reduction compared with conventional columns. The effects of pressure difference on energy saving are analyzed, and possibility of energy saving is found in some case studies