Dear Remy1234
I'm working in a Large LNG plant in Qatar for 21 years, it is difficult to give estimation of cost of LNG process plant since this depends on deferent factors:
1- size or capacity/production of the LNG plant
2- Scope of the plant and configurations and new technology used for mega trains using frame 9 turbine/compressors
3- Experience of LNG process designer who are well known in the filed from France, UK, Japan and Korea.
4- usually owners of LNG plants tends to bid for the lowest price during FEED and EPC phase of project and usually it is a Lump sum project.
I suggest that you consult with LNG Process and EPC contractors or designers.
Thamed57