Indirect heating of oil tank using elctrically heated steam pocket

[Widlof]

I have an application which requires heating of a tank of oil and solvent. This requires a low flux density and competitors are using a sealed pocket, mounted in the side of the tank. This pocket has an electric immersion heater in the bottom, is half filled with distilled water and "sealed for life". Can anybody tell me who manufactures this type of thing or if it is feasible to manufacture them ouselves. Heat input will vary from one project to another but I require around 6Kw for the first unit we are designing.

Thanks in advance, Mike

 

[MechEngNCPE]

I would not use an electrical heating element in the tank. Can you use steam jacketing? or hot glycol? It just makes more sense in this application.

 

[25362]

From past experience I suggest you contact Armstrong-Chemtec for this job.

 

[moltenmetal]

If you are using a laptop, you already have a more sophisticated version of such a thing: it's called a heat pipe. The heat source is your processor chip, and the heat sink is a distance away, next to the vent van. The fluid is usually methanol rather than water.

Yes, this can be constructed, but not without care. Obviously you need to calculate how high the steam pressure could go under the worst case heat removal conditions given your volume, area and how much water you charge the system with initially. Since you have no relief valve, you will be relying on overtemperature detection on the heater and/or intrinsic design to protect against rupture due to overpressure. If your steam pocket chamber is beyond 1.5 cubic feet and has a dimension beyond 6", it's an ASME vessel which requires a relief valve. And if your external environment is subject to corrosion or cracking mechanisms, the risk of a leak or catastrophic failure will always be there. With 6 kW of input energy, the amount of energy stored in the vapour/condensate will likely not be trivial.

If steam is available, it's preferable to use it, provided that you have a means to remove the condensate at pressures below atmospheric, i.e. presuming your condensing pocket surface will be below 100 C.

 

[unclesyd]

If you have steam available you might want to contact CSI about their ControTrace Heaters.

http://www.csiheat.com/products/controtrace/ct_for_tanks_vessels.aspx

 

[racookpe1978]

If you are going to electrically heat the steam from water, then use that steam to heat the vessel and recondense the steam, why not wrap the vessel with the electric heaters directly.

No issues with the pressure control, pressure vessel, leaks, relief valve, internal/external corrosion, etc. you mentioned the low flux (heat transfer) density, but electric heaters do not need an internal element (though most do to make the element more efficient) since even the under-floor heaters have such a low density.

 

[vpl]

competitors are using a sealed pocket...

Is it possible to get a link to a website or a picture as you obviously have something in mind.

Patricia Lougheed

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