Unraveling Heat Integration Opportunities in SOFC–Ethanol Reformer Systems across Steam Reforming, Partial Oxidation, and Autothermal Reforming Pathways

Heat integration is essential to enhance the efficiency of solid oxide fuel cell (SOFC) systems coupled with ethanol reformers, being fundamental to enable their use in onboard applications and distributed power systems. However, a unified, system-level comparison of steam reforming (SR), partial oxidation (POX), and autothermal reforming (ATR) within a single modeling and analysis of heat integration opportunities has been lacking. This study addresses this gap by developing a simulation framework that combines a validated lumped SOFC model with a flowsheet simulation environment to systematically assess the thermal behavior of SOFC-reformer configurations. A design of experiments approach, based on a face-centered central composite design, was employed to generate discrete simulation data, which were subsequently analyzed using analysis of variance (ANOVA) and response surface methodology (RSM). This enabled the construction of metamodels linking key process variables such as reformer and SOFC temperatures, operating pressure, water-to-ethanol, and oxygen-to-ethanol molar ratios to system responses such as electrical efficiency and thermal duties. Results show that the SOFC consistently acts as a net heat source, producing surplus heat relative to the reformer demand, while the temperature gradient between components favors internal recovery. Conditions close to the SR regime were found to maximize the electrical efficiency (up to 36%) and minimize external heating requirements. Based on these insights, a heat exchanger network (HEN) was proposed by using the Pinch method and validated in the flowsheet simulation. The proposed HEN fully satisfied the heating requirements of the system, eliminating the need for hot utilities and improving electrical efficiency from 36 to 52%. Overall, the study demonstrates that thermally integrated SOFC-ethanol reformer systems can achieve self-sustaining operation under steady-state conditions. The proposed unified modeling framework provides new insights into the thermodynamic coupling between ethanol reformers and SOFCs, highlighting ethanol as a viable renewable fuel and advancing the design of compact, fuel-flexible energy technologies for high-efficiency, and clean power generation.