Abstract:

In order to improve the utilization efficiency of LNG cold energy,based on the exergy analysis of the LNG ( Liquefied Natural Gas) cold energy utilization in a low-temperature cold storage and with a binary mixture of a methane-to-ethane mass ratio of 65: 35 as the working fluid,a Rankine cycle utilizing cold energy to generate power is integrated with the refrigeration process of the cold storage utilizing the LNG cold energy so as to not only keep a constant necessary supply of cold energy for the cold storage but also convert the deep cryogenic exergy of LNG in the cold storage to power by the Rankine cycle. Meanwhile,the influences of some parameters of the Rankine cycle on the power generation efficiency are also analyzed. The results show that the proposed integration system not only meets the cold energy requirements of the cold storage but also generates a power of approximately 15. 5 kW·h per ton of LNG,and the exergy efficiency of the LNG cold utilization in the system increases from 38. 5% to 54. 0%.

Key words: liquefied natural gas, cold energy utilization, cold storage, cryogenic power generation, integration, optimization