Electrification of distillation processes through discretely heat integrated distillation columns (D-HIDiC) is an effective approach to enhance energy efficiency and lower carbon emissions. For separating systems with high temperature lift, multi-stage compression and inter-stage cooling are necessary to link the high-pressure rectifier and low-pressure stripper. Traditionally, heat recovery employs pumparound loops, but this study introduces liquid injection as a more efficient and innovative alternative. Simulation results using methanol/water separation indicate that liquid injection reduces both reboiler duty and compression power, achieving up to 50% primary energy savings compared with conventional distillation columns. Unlike continuous heat exchange in conventional HIDiC (C-HIDiC), D-HIDiC simplifies heat integration, avoiding complex hardware and energy penalties. Comparative analysis across multiple configurations, including SuperHIDiC, confirms the potential of D-HIDiC with liquid injection to fully electrify distillation, eliminate steam utility, and significantly support sustainable industrial operations.

A prescreening and decomposition method is presented to analyse heat exchanger networks for retrofitting. The method, called Path Analysis, selects and analyses fractions from the existing network, either by heuristics or by an algorithm. By comparison of all fractions, the critical parts of the network that should be adapted can be identified. The adaptations can be done independent of the remaining network. Thus Path Analysis enables a considerable reduction of the effort in retrofit design. Meanwhile the simplest network adaptations are favoured.

Path Analysis is applied to several cases. The results for an aromatics case are presented. Using the right software tools, the engineering effort can be reduced considerably, compared with existing methods. Solutions tend to be less complex, while the profitability is sometimes higher than was expected from global analysis. With Path Analysis the retrofit design using new multi-stream heat exchangers proved to be straightforward.