During the processing of natural gas liquid ethane is pumps from 28 bar vessels to 76 bar vessels, and while under normal temperatures this can be done easily, Texas summers regularly reach temperatures where ethane vaporizes and creates product loss. Most seals for these systems use a liquid-lubricated seal, but under varying pressures these can warp and leak. Different variations of this type of seal use an inert gas between one or more pressurized faces to prevent leaks, but once the liquid reaches a higher vapor pressure the now gas breaches the seal.
Dry gas seals are simple albeit unconventional in liquid pumping situations. Seals are normally designed for non-contact operation, meaning any turning, ratcheting, or other operating situations can cause wear and eventual failure. Dry gas seals feature a crystalline layer simulating natural diamond to resist chipping and flaking. Furthermore by using an inert gas as the holding pressure, any vaporized ethane must combat a higher pressure to escape.
The increased structural resilience and absence of mechanical contact make these types of seals longer lasting, up to 5 years rather than 3 weeks in this circumstance.
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