Performance and energy cost evaluation of an integrated NH3-based CO2 capture-capacitive deionization process

Abstract

A capacitive deionization (CDI) device was proposed for NH3-based CO2 absorption-desorption process, to reduce the stripper regeneration energy. A rate-based model, RateFrac, was developed for the absorber, along with an equilibrium-based model, RadFrac, for the stripper. The model was verified, and the results have shown good agreement with experimental data. The CO2 capture process, which is integrated with CDI, was simulated and compared with a non-CDI CO2 capture process based on regeneration energy. Operating parameters such as flow rate, lean CO2 loading, and ammonia concentration in the lean solvent were used to analyze the integrated model. Stripper regeneration energy can be reduced by as much as 37.5% by using the CDI setup. Moreover, energy cost estimation was performed using two heat sources (natural gas and coal). CDI saved a maximum of 31% of the energy costs for a natural gas-fired boiler and 12.3% of the energy costs for a coal-based boiler.