Economic evaluation of small-scale LNG production system for shale gas recovery considering life cycle cost with availability

Abstract

This study propose a novel liquefaction system for the recovery of shale gas using cryogenic liquid nitrogen and conducts a Life Cycle Cost (LCC) analysis while considering the availability estimation. The system directly liquefies shale gas using the latent heat of liquid nitrogen and consisted of heat exchangers and expansion valves without compression and expansion engines. To verify the economics of the system compared to that of a conventional liquefaction system based on compression expansion cooling, the LCCs of the two systems are estimated. Because the two systems are subject to a significant difference in reliability and availability, the production loss caused by equipment failure is also reflected in the LCC. The result of LCC showed that the novel system is attractive when the price of liquid nitrogen is less than $60/ton. In addition, the absence of turbo-machines in the system results in less frequent and shorter repair times, which leads to significantly less production loss compared with the conventional system.