The flow-by capacitive ion separation (CIS) device was introduced into the NH3-based CO2 capture process for reducing the regeneration energy. Regeneration energy analysis of the NH3-based CO2 capture process integrated with the CIS device under different flow rates, NH3 concentrations and CO2 loadings of the rich solvent (Richout) flowing into the CIS device was performed. The flow rates, NH3 concentrations and CO2 loadings of Richout considered in this paper are 120-150 L/min, 2.0-3.0 mol/L, and 0.3-0.5, respectively. When choosing suitable operating parameters of the CIS device, the flow rate of the concentrated ion stream flowing out of the CIS device decreases. Therefore, the introduction of the CIS device into the NH3-based CO2 capture process can lead to a significant reduction of the regeneration energy, and the regeneration energy can be reduced by above 20%. Particularly, for the case that the NH3 concentration of Richout is 2.0 mol/L, the regeneration energy can be reduced by up to 35%. (C) 2017 Elsevier Ltd. All rights reserved.