(171c) Floating LNG Plants with Liquid Expander Applications

The future of the world LNG is in the offshore LNG area. This can be evidenced by the recent floating LNG efforts in the offshore area led by major oil companies. The major improvements of applying the Liquid Expanders in the land-based LNG plants are the increase of liquefaction efficiency and the reduction of equipment size and weight. In this paper we want to point out how do we maximize these benefits to benefit the floating LNG plants in the future.

The design of floating LNG liquefaction plants requires designers to incorporate additional parameters to the already well-known parameters of on-shore LNG plants. Those additional parameters are the minimization of weight and geometric dimensions, low positioned center of gravity to stabilize the floating LNG ship, the maximization of efficiency and life time of machineries, that increasing the time between the regular maintenance shut downs. In particular, rotating machineries have to be stabilized against the larger gyroscopic forces caused by the floating LNG ship movements.

The use of Liquid Expanders in floating LNG plants is the effective solution for the above listed parameters by increasing the LNG production output. Liquid Expanders replace the JT valves, reduce the total weight, have a low center of gravity, and are reliably rotating with high efficiency.

This paper describes the different designs for LNG plant Liquid Expanders, their operating characteristics, and compares the on-shore design with the off-shore floating LNG plant design. This paper also points out the important contributions of Liquid Expander to the LNG liquefaction efficiencies and reductions of the total weight and with their low center of gravity.