Abstract:

In this paper, the exergy loss and saved energy in the cold energy utilization of liquefied natural gas （LNG） by means of such technologies as air separation, cryogenic comminution and cold warehouse are calculated and analyzed. Then, a principle of ＂parallel temperature and gradient utilization＂ is presented to integrate and optimize the cold energy utilization of LNG. The results show that, with the integration of the three above-mentioned technologies, the exergy lost of cold energy utilization of LNG decreases by more than 55.7%, as compared with that only with a single technology, and that the largest amount of energy saved in the cold energy utilization with the integrated system for per ton LNG reaches 349.0 kW·h, which is 1.56 times that only with the air separation equipment. It is thus concluded that the integration of the three above-mentioned technologies may greatly improve the utilization efficiency of LNG cold energy.

Key words: liquefied natural gas, cold energy utilization, integration, optimization