Non-equilibrium thermodynamic analysis of adsorption carbon capture: Contributors, mechanisms and verification of entropy generation

Abstract Emissions of greenhouse gases should be reduced for the slowing of global warming. Carbon capture by adsorption, which is available to retrofit of existing power plants and to integration with renewable energy, is an effective technology to reduce CO2 emissions. However, the heavy energy consumption has already become a limitation to scale-up applications. Thermodynamic research, especially entropy analysis, could quantitatively clarify the irreversible loss and provide a guidance to the energy-saving design. Considering that classical thermodynamics is powerless in the description of significant kinetic characteristics of adsorption carbon capture, non-equilibrium thermodynamics is thus required, as it could provide a detailed analysis on the contributors and mechanisms of entropy sources. In this paper, the entropy source contributors of adsorption systems, which are composed of entropy generation of 9 irreversible factors for different adsorption cycles, were derived. An entropy research framework was proposed and illustrated through a case study of vacuum temperature swing adsorption (VTSA). The results are also compared with the classical exergy method, and the difference between the results of the two methods for entropy generation is 1.97%. This paper provides a thorough research framework for detailed thermodynamic analyses of adsorption carbon capture.