Simulation and analysis of a peak regulation gas power plant with advanced energy storage and cryogenic CO2 capture
Na Wen, Hongbo Tan, Xiaoqiao Qin
Abstract
Flexible gas power plants are subject to energy storage, peak regulations, and greenhouse gas emissions. This study proposes an integrated power generation system that combines liquid air energy storage (LAES), liquefied natural gas (LNG) cold energy utilization, gas power systems, and CO2 capture and storage (CCS) technologies, named the LAES-LNG-CCS system. The off-peak electricity can be stored in liquid air. During the peak period, air and gas turbines generate supplementary electricity. Both LNG chemical energy and cold energy were considered: the former was used for gas power plants, and the latter was used for LAES regasification and CCS processes. Based on the thermodynamic analysis, we evaluated the effects of the recovery pressure, CCS pressure, and combustion temperature on the system power consumption and efficiency. The results demonstrated that the system recovery pressure, CCS pressure, and combustion temperature had the greatest effects on system power generation. Round-trip efficiency (RTE) was significantly affected by combustion temperature. The largest exergy loss occurred in the gas power plant. The optimal system operating ranges of the system recovery pressure, CCS pressure, and combustion temperature were 6−10 MPa, 0.53−0.8 MPa, and 1,503−1,773 K, where the RTEs and ηEx,RS reached 55%−58.98% and 74.6%−76%, respectively. The proposed system can simultaneously achieve the synergistic functions of large-scale energy storage, multilevel energy utilization, peak regulation, and carbon emission reduction. It can also be widely used in advanced distributed energy storage applications in the future.