Recently the demand of LNG has increased and will continue to increase in near future. To meet this demand exploration has gone into offshore with the Development of FLNG, with one of them having completed his first off take to an LNGC and several of them under Construction at the time this Technical paper is prepared.
One of the challenges lies in the correct selection of the driver for LNG refrigeration compressor on FLNG. Although both mechanical drive as well as electrical drive is applied on land based LNG plant, the situation is quite different in offshore as very limited experience is available and no electrical drive has been selected so far for FLNG facility.
The findings on drive selection and their economic and operational advantages are discussed in this paper.
Power generation system and refrigerant compressor system are very important systems to be evaluated together for the FLNG facility to achieve optimum solution.
FLNG has limited space, sensitive to motion, standalone power generation, inherent difficulty for providing maintenance support and limited operating staff. These factors are well known to FPSO/ FLNG providers and all of them will agree that driver should be simple, robust, reliable and cost effective.
We have three types of choices available for such large compressor i.e. steam turbine, gas turbine (GT) and Electric Motor (EM). Comparison focuses on the GT and EM along with their characteristics
FLNG facility does require standalone electric power generation on board. The electric power generation can be achieved either by GT generator set, steam turbine generator sets or gas engine sets. The power generation has impact on driver selection in terms of improving thermal efficiency, availability, inventory control and use of fuel.
There are several parameters which need to be considered for evaluation before finalizing the driver selection for Refrigeration compressor on FLNG. A case study previously developed under OTC-27731 (Associated Gas FLNG with One or Two Liquefaction Trains) is used to map these parameters to depict the reality of driver on small to mid-scale FLNG facility
Therefore, this paper will evaluate how to select correct driver system for refrigeration compressor considering all the factors. It will also provide useful guidelines for owners, field operators, designers and EPC contractors to arrive at right solution for their specific application.