Current Operational LNG Expanders

The liquefaction of Natural Gas requires a large amount of energy and many improvements were established since the first commercial natural gas liquefaction plant was built in 1917 in West Virginia. One of the main improvements for the efficiency is the increase in pressure. By compressing the incoming feed gas to a higher density the plant efficiency increases and the costs for the liquefaction reduces.

The Liquefied Natural Gas LNG is transported and stored at atmospheric pressure and it is necessary to expand the high pressure condensed LNG after the liquefaction to atmospheric pressure. This expansion is performed by cryogenic LNG expanders in current plants and by Joule-Thomson valves in older plants. The expansion across an LNG expander increases the output of the liquefied LNG and significantly reduces the costs for the liquefaction. The paper presents the design of the current operational LNG expanders.