LNG Expanders for Small Scale LNG Liquefaction Plants

Small scale liquefaction plants for natural gas operate at low flow and at high pressure to produce LNG at competitive costs. The same type of turbomachinery that is used in regular liquefaction plants, like compressors, gas expanders, pumps and liquid expanders, is also installed in small scale plants. All turbomachinery with centrifugal design have a low efficiency if the pressure difference is high at low flow rate, increasing the costs for the liquefaction. To achieve competitive liquefaction costs, the design of the liquid and two-phase LNG expanders is of non-centrifugal design and is presented in this paper.