Selection of automatic control valves for coal tar pitch systems
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Dear forum members, please discuss which type of automatic control valve is better for asphalt pipelines: sleeve valves, double-seat valves, or straight-through single-seat valves? Which one do you usually choose? Are there any that use automatically adjustable ball valves? How is their performance? I would appreciate your advice!
We are using eccentric rotating ball valves, and the results are excellent
Either a straight-through single-seat valve or an eccentric rotary valve will work just fine
Is there incomplete purging of the direct-through single-seat valve?
Blow for a longer period during purging, and then ensure proper heating of the control valve; it’s best to use heat transfer oil for this purpose, as it yields good results
I feel that while the type of control valve is certainly important, in terms of pipeline design, it is crucial to ensure good flowability of asphalt at the outlet of the control valve.
On the top floor, it’s advisable to set a leakage limit for the asphalt system control valves on the DCS; this way, there will still be some flow even when the valves are fully closed, ensuring that blockages do not occur
Thank you all for providing the information. I have another question: does the rotary eccentric control valve have near-percent characteristic, allowing for precise flow control? Especially in cases with cascade control of liquid level and temperature, where the control requirements are particularly high?
Our company uses rotary eccentricity control, which is also integrated with temperature and liquid level cascade control. It has worked very well; as long as the PID settings are adjusted properly, full automation is achieved
It is best to use insulated gate valves, as they are less prone to clogging