Expanders Overview


Cryogenic Expander Post-Test

For many years, the traditional method to let down pressure in a liquid stream used a Joule-Thomson (J-T) valve. An improvement in the overall efficiency of this let-down process can be achieved by replacing the J-T valve with an expander. In doing so, and depending on the machine, the overall plant efficiency may increase up to 8%, reducing operating costs and increasing LNG production.


By using the technology and extensive experience from the proven Cryodynamics pump design, an extremely reliable and efficient expander was developed. The cryogenic expander is a radial inflow reaction with an induction generator mounted on an integral shaft. The entire unit, including the turbine and generator, are totally submerged in the cryogenic fluid. This design completely eliminates the need for dynamic seals, shaft couplings, generator support structure, and any concern for possible misalignment between the turbine and generator. By eliminating possible leakage from rotating seals, the design is extremely safe, especially when hazardous fluids are being handled.

To ensure reliability and increase mean time between overhauls, our expanders use the same