Realizing dynamic storage of carbon dioxide and waste heat recovery by integrating methane reforming with CSP-CaL system

Abstract

Until now, the concentrated solar power (CSP) with calcium looping (CaL) system developed by scholars has played a key role in the utilization of solar energy. However, a huge quantity of heat loss of heat exchange network and power demand of compressor limits the large-scale application of the system from a system perspective. In this work, we successfully solved the above problems by integrating the methane reforming (MR) subsystem with the energy storage (ES) and energy release (ER) units of the conventional CSP-CaL system to build two novel types of CSP-CaL-MR systems, respectively. Then an overall design and optimization strategy for both two CSP-CaL-MR systems based on the thermal dynamic properties was proposed. After considering parameters such as the efficiency of power generation, efficiency of hydrogen production, and overall energy consumption of the system, we comprehensively evaluated the two systems. The results showed that the CSP-CaL-MR (ES) system not only achieved dynamic storage of CO2, but also increased the efficiency of power generation by about 4% through abandoning the compressor used to store CO2 in the conventional CSP-CaL system. The CSP-Cal-MR (ER) system reduced the waste heat loss of the heat exchange network by 45% through balancing the mass flow of CO2, CaO and CaCO3/CaO at the hot and cold ends of the heat exchangers. Meanwhile, the supercritical carbon dioxide Brayton cycle integrated in the MR subsystem can output 4.13 MW of net power, which is equivalent to 20% of the 20.86 MW of net power output from the CSP-CaL subsystem.