heating/cooling control

[lotus7312]

Dear all,
I have one project to get a better control for a vessel during heating/cooling.
There are steam and water line for this vessel. Currently,steam is on for a few minites to reach to certain temperature. Then open water vavel and crack steam valve to maintain the target temperature.
My idea is to have a heater in water line. The heating medium is steam. Two control valve cascaded based on the vessel temperature: one is on the water line, one is on the heating medium of the heater. Is this idea good to achieve the target? Anyone have better and easier idea?
Any suggestions are appreciated.
Regards

 

[jdaden]

Hi lotus7312

A variation that works well is to have a bypass with flow control valve over the heater, and another flow control valve on the cold feed to the heater. You then control the temperature of the outlet by setting the ratio of the two flow rates, and you do not need to control the heating medium. In practice this method is fast, stable and controls within 1 deg C. A reminder: If you intend to exceed boiling point on the water side, remember to include a pump to raise the pressure substantially above the vapour pressure. Hope this helps.

 

[25362]

Don't block with valves the water line without a vent and RV to avoid overpressures developing on heating.
If you plan to mix steam and circulating cooling water beware of depositing insoluble salts.