Design-oriented thermodynamic analysis of novel heat-integrated C5 isomeride distillation scheme on pilot scale

Abstract

A novel heat-integrated distillation scheme on pilot scale for producing C5 foaming agent, a mixture of isopentane and pentane in a certain proportion, was proposed with the aid of process simulation. Compared with the conventional distillation scheme, C5 foaming agent was directly separated at the top of the original isopentane or pentane column in the novel scheme, instead of first refining the two isomerides to high purities and then mixing them into final products. This improvement reduced the difficulty of the separation and avoided meaningless exergy loss caused by re-mixing, which finally contributed to an energy-efficient design by a big margin. Moreover, the column grand composite curves(CGCCs)were used to modify all distillation columns, indicating that there is potential to improve the energy efficiency further. Therefore, double-effect, or heat-integrated distillation was also adopted. Energy and exergy analyses were then conducted to evaluate the effectiveness of the proposed scheme for the purpose of energy saving. The simulation results of the conventional distillation scheme were in agreement with its on-site counterpart. Analyses showed that the novel heat-integrated scheme reduced hot utility by 27.12%,, cold utility by 24.49%,, and total exergy loss by 23.95%,.