LNG cold and cryogenic recovery
Using the cold released when LNG or liquid air warms up.
Recovery and reuse · Pressure, motion and waste fuels · No. 135
- Recovery and reuse
- Waste energy: Cold
LNG arrives at minus 162 C, and most terminals simply warm it with seawater, throwing a fortune in cold away.
Chart: Illustration: LNG cold and cryogenic recovery
Where it comes from
Chart: Map of where it comes from
Every kilogram of LNG releases about 830 kJ of cold as it turns back into gas. Because it is 180 to 190 degrees below ambient, that cold is thermodynamically valuable.
Three things to know
- Seawater vaporisers destroy most of the cold's work potential; even in Japan not much more than 25% is captured.
- Dahej's theoretical cold is about 5.2 TWh a year, roughly 590 MW on average, if it were all put to use.
- Liquid air storage pays back in about 20 years alone, but about 3 to 10 years when paired with LNG cold or waste heat.
The journey
- 1 LNG tankerLiquid gas at about minus 162 C
- 2 RegasificationWarmed and expanded about 600 times
- 3 Cold captureExchangers pass cold to an intermediate fluid
- 4 Cold usersPower cycle, air separation, cold stores
- 5 Grid gasWarm gas sent out to customers