Gas Processors Association Europe

Joseph Kugler, Air Products Air Products and Chemicals, Inc, USA

The desire to increase single train LNG production while staying within the constraints of proven and available equipment has led to the development of the AP-X® process cycle.  This cycle uses multiple large scale turbo-expander/compressors (companders) in a nitrogen refrigeration loop for the final stage of LNG sub-cooling.

Four 7-MW companders operate in parallel in each of six process trains. Dry gas face seals are used to minimize loss of the nitrogen refrigerant to atmosphere.  High capacity oil thrust bearings allow application of a simple, intrinsically safe, passive thrust balance arrangement.  A common lube oil system is used for all 4 companders.  A CCC control system manages load sharing and surge protection.

Challenges and achievements throughout the design, installation, commissioning and final on-stream operation are reviewed.