LNG冷能用于冷库制冷性能模拟研究

为使LNG冷能在冷库系统中得到有效利用,从LNG冷能梯级利用的角度出发,设计一种新型LNG冷能制冷的冷库系统,在LNG换热器端和冷库末端实现对LNG冷能的梯级利用,并通过HYSYS模拟对其进行热力学分析和经济性分析.结果表明:该冷库系统COP为1.82,火用效率为80.2%;LNG换热器火用损最大,约占系统总火用损的78.9%,且随LNG进口温度升高而减小;系统COP和火用效率均随LNG进口温度及气化压力升高而增大;该系统投资回收期为4.77 a,具有较好的经济效益.LNG冷能为冷库系统冷量来源提供新的选择,在LNG进口端增设蓄冷设备和加压泵均能提高系统COP和火用效率.

Simulation study on performance of the cold storage using LNG cold energy

To use LNG cold energy in cold storage system effectively, a new cold storage system using LNG cold energy was designed from the perspective of cascade utilization of LNG cold energy, which achieved cascade utilization of LNG cold energy in the LNG exchanger and the cold storage terminal. In addition, the thermodynamics and economy performance of the system were simulated and analyzed by HYSYS, respectively. Results indicated that COP of the cold storage system was 1.82 and the exergy efficiency was 80.2%. Besides, the exergy loss of LNG exchanger was the largest, which constituted 79.8% of the total exergy loss in the system, and it decreased with the LNG inlet temperature rising. Moreover, as the LNG inlet temperature and gasification pressure increased, both COP and exergy efficiency of the cold storage system rose. The system had good economic benefits, with the payback period of 4.77 years. It was quite obvious that LNG cold energy was a new cold energy source for cold storage system and adding cold-storage equipment and pressure pump in LNG inlet terminal could improve COP and exergy efficiency.