Energy minimization of carbon capture and storage by means of a novel process configuration

Abstract

Carbon capture and storage is considered a key technology for decarbonizing the heat and power industries and achieving net zero emission targets. However, the significant energy requirements of the process as currently utilized hinders its widespread implementation. This work presents a novel process configuration by which the energy expenditures of carbon capture and storage can be minimized. This configuration is intended to enhance heat integration during the capture process through an innovative combination of three stripper modifications, namely lean vapor compression, a rich solvent split with vapor heat recovery and reboiler condensate heat recovery using a stripper inter-heater in a single flow-sheet. For carbon dioxide compression, a novel pressurization strategy involving carbon dioxide multi-stage compressors, a heat pump system and a supercritical carbon dioxide power cycle was designed and evaluated. The heat pump was used for carbon dioxide liquefaction while the supercritical carbon dioxide power cycle was employed to recover the intercooling heat. Through a comprehensive parametric investigation of the proposed configuration, the optimum value of the key operating parameters i.e., the split fraction, flash pressure, stripper inter-heater location, stripper inter-heater solvent flowrate, carbon dioxide liquefaction pressure and supercritical carbon dioxide cycle turbine pressure ratio were estimated. The performance of the proposed design at the optimized condition was quantified in terms of the reboiler heat duty, the carbon dioxide pressurization power and the equivalent work and compared to a baseline case post-combustion carbon capture and storage process. The proposed case reduced the reboiler heat duty from 3.36 GJ/TonneCO2 to 2.65 GJ/TonneCO2 and the electric power required for carbon dioxide compression from 16,691 kW to 14,708 kW. The results demonstrate that the new design can significantly reduce the reboiler duty, compression power and equivalent work by 21.1%, 11.88%, and 15.8%, respectively.