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We use a hot oil system. We are facing frequent failure of gaskets in it. The operating temperature is 330 dec C and pressure around 15 bar. we are currently using metallic spiral wound gasket. These leaks are resulting into unit shutdown or online sealing.
1. Do others have the same issue of gasket leaks in hot oil system?
2. What kind of gasket will resolve above issue?
3. Any special make of gasket?
4. Might changes in operating condition help?
 
Answers
19/06/2014 A: Raghavendra Sangam, Larsen and Toubro Ltd, rsangam0504@yahoo.co.in
In hot oil systems (Therminol 66 or Dowtherm or any such HTM) with the temperature and pressure as mentioned, it is the industry practice to avoid flange joints as much as possible. That woud be at design and construction stage. To manage the present problem:
(1) Replace the flange joints in the piping, if possible, in the next opportunity for a shut-down. If it is a valve flange, replace the valve with a welded-end valve that can be maintained with bonnet-opening.
(2) If the flange joint can not be replaced with a weld joint, ensure the piping and flange alignment is perfect and the flange surface is not damaged.
(3) Check the recommended/design specs of the SW gasket and whether the gaskets used are suitable for the service. 316 Ti Spiral, graphite fill with both inner and outer ring in the gasket should be sufficient.