Integrated Heat Exchanger Network and Postcombustion Carbon Capture Synthesis for Decarbonizing Crude Oil Distillation under Multiperiod Operation

Abstract Conventional decarbonization through heat integration works by two mechanisms: process–process (PP) heat recovery, which lowers fuel usage but is limited by minimum temperature differences; and process–utility (PU) waste heat recovery, which offsets boiler demands by utilizing surplus heat. Building upon prior methodologies, this study proposes a systematic optimization approach for multiperiod heat exchanger network (MP-HEN) synthesis integrated with a postcombustion carbon capture (PCC) process to improve sustainability and reduce carbon emissions. The heat sink set is extended to include the stripper reboiler duty of the PCC column, which is regressed as a function of fired heater load derived from HEN fuel gas consumption. The regression is supported by a sequence of analyses based on rigorous N-methyldiethanolamine/piperazine (MDEA/PZ)-based PCC simulations. Carbon capture costs associated with variable reboiler duty are incorporated into the Total Annual Cost (TAC), enabling simultaneous economic and environmental optimization within a multiobjective optimization function. The PCC heat demand is supplied by recovered HEN waste heat and, when required, external hot utility input. Using a three-step decomposition algorithm, the method optimizes the HEN configuration, integrates PU heat transfer for carbon capture, and performs module simulations to validate overall system performance. An industrial-scale crude oil distillation preheat train case study demonstrates that the framework can effectively decarbonize the crude distillation system. Relative to the Base-WRDC benchmark, the integrated PCC-HEN solutions achieve a 38.1% CO2 reduction at 15 °C while maintaining a lower TAC. Relaxing the minimum approach temperature to 10 °C further increases the CO2 reduction to 65.0%.