An Improved Combined Power System Utilizing Cold Energy of LNG

In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energy of liquefied natural gas(LNG) could be fully utilized as well. A system simulation and thermodynamic analysis were carried out,the Kalina cycle was reorganized by changing the concentration of "basic composition",so that a better thermal matching in the heat exchanger could be obtained and the irreversibility of the system was decreased. It was found that the Kalina cycle generally used in the bottom of combined power cycle could also be used to recover the cold energy of LNG. The results show that the exergy efficiency of 42.97% is obtained. Compared with the previous system attained the exergy efficiency of 39.76%,the improved system has a better performance.