Cryogenic turboexpander is considered;
as the heart of modern gas liquefier for its high
thermodynamic efficiency and high reliability. The
operating speed of small-sized turboexpander is usually
greater than 50,000 rpm. Such high rotational speed
brings constrain in the selection of the bearings. Oil-free
gas bearings is a novel approach to keep the process gas
contamination free. In the current research, a pair of gas
foil thrust bearings (GFTB) are designed and developed
for a vertical turboexpander used in nitrogen liquefier.
The rotational speed of the rotor is 80,000 rpm with an
axial load of 83 N in the direction of turbine wheel. The
author believes the detailed design and development
methodology will be helpful to the bearings designer
around the globe.