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Fossil-fueled power plants are a major source of carbon dioxide (CO2) emission and the membrane process is a promising technology for CO2 removal and mitigation. This study aims to develop optimal membrane-based carbon capture systems to enhance the sustainability of fossil-fuel power plants by reducing their energy consumption and operating costs. The multi-stage membrane process is numerically modeled using Aspen Custom Modeler based on the solution-diffusion mechanism and then the effects of important operating and design parameters are investigated. Multi-objective process optimization is then carried out by linking Aspen Plus with MATLAB and using an evolutionary technique to determine optimal operating and design conditions. The results show that, as the CO2 concentration in the feed gas increases, the CO2 capture cost significantly decreases and CO2 removal is enhanced, although the process energy demand slightly increases. The best possible trade-offs between objective functions are reported and analyzed, which confirm the considerable potential for improving the sustainability of the process. The CO2 capture cost and energy penalty of the process is as low as 13.1 $/tCO2 and 10% at optimal design and operating conditions. This study provides valuable insight into membrane separation and can be used by decision-makers for the sustainable improvement of fossil-fueled power plants. [ABSTRACT FROM AUTHOR]

• A rigorous dynamic model is developed to investigate the dynamic performance of a single-stage counter-current membrane system. • Undershoot and overshoot behaviors are detected by decreasing and increasing the inlet pressure, respectively. • The membrane module responds slowly to step-changes in feed composition and retentate recycling. • Reducing the feed pressure increase the required membrane area to achieve the separation target. Renewable energy sources and fossil-fueled power plants integrated with carbon capture technologies are expected to play an important role in sustainable energy supply in the future. In this regard, this study aims to improve the flexibility of membrane-based CO 2 capture units as a promising technology for CO 2 capturing by analyzing the system's transient behavior. A rigorous dynamic model for a single-stage membrane separation system is developed, which includes differential equations of transport phenomena across the membrane, mass balances, and pressure distributions. The model is utilized to investigate the dynamic performance of a single-stage counter-current membrane module for separating CO 2 from the flue gas of a power plant, including up to 13 vol% of carbon dioxide. Step-changes in feed pressure, feed flow rate, feed composition, and retentate recycling are considered for the analysis. The results show that by step increase in feed pressure from 5 to 8 barg, undershoot behavior is detected, and the membrane module requires about 7 s to reach a steady-state condition. In contrast, by step decrease in feed pressure, there is an overshoot, and the module requires 11 s for new steady. Also, the membrane module responds slowly to step-changes in feed composition and retentate recycling (∼20 s) compared to other step-changes in operating conditions. This paper provides new insights into the dynamics analysis of the membrane process as well as the flexible operation of membrane-based carbon capture systems. [ABSTRACT FROM AUTHOR]