Place:
Supercritical Boiler North America
Challenge:
Seal a leaking boiler attemperator valve packing operating at 4500psi-300f. The issue with all attemperation valves is the nature of the continual movement of the valve. This makes sealing them difficult and keeping them sealed long term even more difficult. The rams are often cut, and this damages the injected sealant with every movement of the valve. It was summer and the plant was making 800 megawatts from this unit. Because they were at full demand the attemperation valve was in daily movement.
Solution:
RJ Stacey with years of experience and thousands of these types of repairs developed our own proprietary sealant blends. The key was a sealant which had the bridging abilities to span the leak path gap and had self-healing properties that allowed for the movement within the packing gland when the valve cycled. First RJ Stacey technicians met with plant operations to determine the proper sealant choice based on water chemistry, valve type, leak severity, and other compatibility factors. Then they inspect the valve and locate proper injector placement, next the appropriate sealant was injected.
Results/Benefits:
The leak was sealed without affecting operations and lasted several months of service in a leak-free condition. The plant was relieved of the safety hazard the leaking valve was presenting. Additionally, the injector we used on this repair was a 3/16-18 bolt pattern design we have custom made for RJ Stacey. This allows for very simple removal and seal weld of the injector location at a later date. Also, the proprietary sealants used had no effect whatsoever on chemistry or any mechanical function downstream.
