Carbonation heat recovery via dry reforming to improve the techno-economic performance of the Ca-Cu looping post-combustion CO2 capture

Abstract

Calcium looping process has presented great potential realizing low-energy-consumption CO2 capture since high-grade thermal energy can be recovered. However, in current calcium looping configurations, the carbonation heat is recovered for steam generation, resulting in the significant exergy destruction. This study presents a novel Ca-Cu looping process with thermochemical recuperation to address the significant exergy destruction during carbonation heat recovery. System integration is carried out for the typical flue gas decarbonization. Results indicate that the proposed system present superior performance than that in the reference system without thermochemical recuperation. The specific primary energy consumption for CO2 avoided decreases from 2.29 MJLHV/kg CO2 in the reference system to 1.68 MJLHV/kg CO2 in the proposed system. Energy analysis and exergy analysis reveal that carbonation heat recovery via thermochemical recuperation and efficient utilization of the increased chemical energy contribute to reduction of energy consumption. The research also examines how operating conditions impact the thermodynamic efficiency. An optimized primary energy consumption for CO2 avoidance of 1.58 MJLHV/kg CO2 can be achieved through the response surface method. Besides, the cost of CO2 avoided can achieved at 37.52 €/t CO2, which is more economically feasible with that of the conventional calcium looping technology.

Keywords

• Ca-Cu looping
• Dry reforming
• Thermochemical recuperation
• CO2 recycling
• Post-combustion CO2 capture