Electrical heating and cooling by cold water in a jacketed vessel

[engineer12311986]

I am a bit confused on the options for a jacket vessel.
My process requires heating and cooling. I know I have the option of electrical heating vs. steam heating, and for cooling I will use cold water.

If I want to use electrical heating in the jacket, how does that work? Do I have one set of coils that heat via electricity and other set that carries cold water? Or can I have one set of coils that can at one time be a source of heat and at another time be filled with cold water?

By the way, this is for an agitated jacketed vessel for manufacturing shampoo. Thanks!

 

[jmw]

I thought that by jacketed you meant the tank was double walled for the heating/cooling medium in the cavity but if you are asking about coils then I assume that you mean it is an insulated tank.

In the pharmaceutical industry, for example, the same jacket (coils) are used for both heating and cooling.
The reaction is initiated and maintained by steam flow.
When the reaction is to be quenched they use changeover valves to switch from steam flow to the tank over to water/glycol.
Of course, this is managed by using some form of detection to detect when the steam (or hot water) is switched over to coolant and they monitor the water glycol concentration in the return to the hotwell to detect when the changeover valves are leaking and allowing steam to condense into the water/glycol.

JMW

http://www.ViscoAnalyser.com

 

[gerhardl]

Use steam if there is any size at all of your production. This is a known technology, and you can buy all necessary components off the normal manufacturing market, or perhaps used vessels.

Take a look at the basic physics and see the many-fold increased heat transport capacity of heat by steam compared to hot water. Compare amount of steam to amount of water, and compare time of heat transfer from water at x degrees, to total heat amount from steam at y degrees, but freeing far more energy when condensing.

Doing the heating correct by steam you could produce faster, and increase your capacity or utilize downsized equipment.

If you after this still is sticking to electricity I will guess your warming methode is depending on how much heat your batch can have locally.

If the process run wild (coagulates) at local overheating, you will want to spread the heat around outside the vessel, if not, you could look at coils directly submerged for heating (if practical and possible for cleaning and corrosion etc.)

The best would probably bee to use an electrical water heater as used in ships, placed outside your jacket and pump circulate through your jacket with an extra insulated reservoir vessel for the hot water in the circuit.

The answer to your question then would be yes: you can by a simple isolation valve arrangement use the same coils or jacket around the tank both for hot and cold water.

 

[moltenmetal]

If indeed this thing has a jacket and the jacket is the only means to heat/cool the fluid in question, AND your operating temperature is below 100 C, your best solution will be a tempered heat transfer medium flowing in the jacket. Otherwise, you're talking about switching the jacket over from from condensate to cooling water and back again etc.- lots of inconvenience, slow response and a serious risk of scale formation in your equipment over time if your cooling water isn't so good.

The best way to do this is to build or buy a little closed loop tempering circuit. You need a pump, a storage tank, a heater and a cooler, and appropriate controls.

If your tempering fluid can be water, what you'll want to use is condensate. Heating can be via either live steam injection or via a steam/water heat exchanger, or via an electric immersion heater in a pipe shell or stabbed into the storage/expansion tank. Cooling can be via a water/cooling water exchanger or an air cooler. You'll want the exchanger to be in the flowing line rather than trying to put a coil in your expansion/storage tank: the latter will respond too slowly and waste too much cooling water. If you're going to use live steam, you need to consider the overflow condensate.