Examination of Methods of Dry Gas Seal Supply, Regulation, and Monitoring

Abstract

Compressor Dry Gas Seal Failure is a common issue that affects Turbomachinery train availability. Since most turbomachinery trains are un-spared critical assets, unscheduled shutdowns have a major impact to the operating facility. As operators look to extend equipment run time, the quality and delivery of the primary seal gas supplied to the dry gas seal is vital to the long term operation. In case of a failure, automated trips can be applied to mitigate catastrophic failures but in many cases the machinery engineer needs to make an operations decision due to changing seal performance and needs to answer the following questions: • Is gas delivered to the seal at required volume and quality at all operating conditions? • How is the seal monitored? • What is the data telling me? • What is causing the abnormal indication? • What action should be taken? This tutorial examines the two main philosophies for delivering seal gas, comparing them with two calculated examples before describing a recommend primary vent monitoring setup and the associated instrumentation. The tutorial concludes with several examples based off real world failures to further illustrate the monitoring and diagnostic abilities of the dry gas seal system.