Dry gas sealing solutions for high-pressure compressor applications

Abstract

Although the use of dry gas seals (DGSs) in process centrifugal compressors has become an industry standard since the 1980s end users are still facing operational issues related to premature failures which incur significant maintenance and operational costs. It has been recognized that the majority of the failures are due to a lack of properly conditioned seal gas and this has driven more recent development of Gas Conditioning Units (GCUs) to deliver appropriate quantities of clean, superheated gas to the seal at the required pressure. However, there are a large number of operating units where retrofit of a GCU represents significant cost and engineering challenge. The aim of this paper is to share some recent experience of a DGS reliability improvement program that does not involve retrofitting a GCU. A basic introduction to DGS operating principles and an overview of DGS design and control issues is also included with a focus on tandem seals in high-pressure natural gas compression applications.