Heat Transfer Fluids Valve Selection

[NCENG78]

We have a mixture of isolation valves in our plant for Hot Oil (CALFLO). Triple offset butterfly, globe (Y and std), and gate. For pure line stop valves would you chose Butterfly, Y globe, or Gate? Oil runs at 550F

 

[gerhardl]

Normal (main) selection criteria (for all types of valves, for all fluids):

1. All valves to qualify for all operational data.
2. All valves with references of longtime operation for similar fluid operational data.
3. Operational time and operational forces and cost(actuators?)acceptable.(ESD,waterhammer or prolonged OK?)
4. Flow resistanc loss resistance acceptable for single valves and the total system.
5. Final selection based on availability and price/lifetime cost. (Don't forget maintenance and factory downtime cost, spareparts and replacement cost if cheaper valves have shorter standtime).

Without this detailed knowledge of each single type, it is not possible to select one or the other. Experienced operators will often have preferences for types and brands. The reason will be found in practical experience based on the points above.

 

[moltenmetal]

The only time I would use Y globes as stop valves is in very small linesizes and where you may also want to use the stop valve for throttling/distribution balancing.

I have no experience with triple offset metal-seated butterfly valves. I suppose they have the opportunity to be cheaper than gate valves with similar overall performance in a low differential pressure service like hot oil, but below 2" where most of our hot oil valves lie, the gate is still king for pure blocking/isolation service.

Hot oil is notorious for packing leakage. Some of our clients insist on bellows sealed for this service to avoid constant packing adjustments on the grafoil packings of various valves, in which case their options are limited to rising stem rather than rotating stem products.