Avoid Seal Contamination With Reliable Gas Supply

Causes, consequences and analyses of dry gas seal damages during operation and pressurized hold

By Daniel Goeble and Glenn Schmidt

Centrifugal process gas compressors are needed in the supply chain for oil production and refinement and are used in applications, such as carbon dioxide (CO2) reinjection, refining processes and petrochemical and chemical operations.

Backup compressors are usually not needed when compressors are applied, even though they are critical for the operation of a plant. This is due to the cost of duplicating this type of equipment. Process gas compressors, therefore, must fulfill very high requirements with regards to availability, reliability and safety.

Centrifugal process gas compressors are typically equipped with gas seals to prevent gas from escaping between the stationary compressor body and the rotating shaft. Compressors are normally shut down when high seal leakage occurs, indicating a seal failure. Shutting down on high-seal leakage helps meet safety and environmental requirements and avoid further damage to the equipment. As a consequence, gas seals were designed to fulfill safety and reliability requirements for the industry.

To meet these requirements, the effectiveness of gas seals is determined by the quality of gas supplied to the seal. From experience, we have identified the major root cause for high gas leakage to be contamination of the seal.

Contamination Of Dry Gas Seals

Through Process Gas The key elements within a dry gas seal are the seal faces and secondary sealing elements. A shaft sleeve, which is fixed to the compressor shaft, holds the rotating seat. The rotating seat is sealed against the shaft sleeve with a secondary sealing element, which is a special O-ring or polytetrafluoroethylene (PTFE) filled sealing device. . . .

Read the full story in the November issue of COMPRESSORTech².