By replacing a large, fragile graphite package with a robust chamber profile in an optimal design, Gas Storage Denmark avoids leaks and is now back in operation within half a working day when maintenance is carried out. This is 75 percent faster than before.
More often than necessary, Gas Storage Denmark experienced leaks from a glycol heater that ensures the separation of condensate from the natural gas distributed from two national underground gas storage facilities. The leaks from this secondary system are not critical, neither in terms of safety nor the gas supply task, but they entail many unnecessary and time-consuming maintenance work. Replacing the previous seal was an arduous task that required not so few people: Graphite seals with a diameter of 1.4 meters are quite unstable and easily damaged.
The glycol heater (a heat exchanger) operates at low pressure and low temperatures up to 200 °C. In addition to the packaging size, which was difficult to handle, it was obvious that another type of seal should solve the task better. The product expert from Betech recommended an application-specific chamber profile (a fluted metal seal) coated with Sigma® 500, a high-end PTFE quality from Flexitallic®.
No fewer than 52 flange bolts make it difficult to install the bolts through the usual circular bolt holes in the gasket. Therefore, the new cam profile is designed with oval holes that facilitate the installation process. The technical support also included other critical parts of the sealing system: all the bolts, nuts and washers were replaced with new ones, and the flanges were refurbished to ensure flat, parallel surfaces.
Finally, the correct torque and tightening method were reviewed with the maintenance team.
The leaks have stopped and the service interval has been significantly extended following the refurbishment of the flanges, the replacement of the bolts, and the use of a type of seal that is more suitable for the application. Additionally, an intelligent seal design makes handling and installation much easier, and significantly reduces downtime. Maintenance work can now be carried out in a third of the time previously required.
