Dear ALL,

I am designing a Pilot Plant (about 1 kilo/day capacity). I need to heat streams going to a reactor to 250 deg F. I am looking to use oil to heat the streams with regular S&T Heat Exchangers. I am looking for an electrical heater that uses oil (such Conoco HT) as heat transfer medium and is compact. Does any one have any experience in this field so that you could make some suggestions/recommendations? What other info is necessary to choose a suitable heater?

Thanks in advance, dogtop

For either flanged immersion heaters (to build your own hot oil system) or for complete hot oil systems, you can try Gaumer or CCI Thermal Technologies.  There are lots of others.  A Google search will point you to both of these.

For a complete pilot unit, consider Zeton (www.zeton.com) .  They're specialists in pilot- and demonstration-scale plants.

Is there a reason you want to use shell and tube exchangers utilizing hot oil to do this?

Chromolox and Armstrong both make electrical heaters suitable for gas and liquid service, why not just use them directly and cut out the exchangers and hot oil equipment?

TD2K's recommendation makes all the logical sense in the world.  This is what I and others have done in the past in developing pilot plant data or assembling pilot units.

Without a doubt, Chromolox comes into the picture with vast experience and know-how.  I've used their heater for over 40 years - without a complaint or care.  They furnish design tips, recommendations, and formulas.  Their hardware is by far, one of the most reputable in the industrial applications field.  If you follow TD2K's tip you can't go wrong, in my opinion.

TD2K, My safety people has recommended I do what I described. Safety is first! Thank you for your suggestions and concerns.
Thanks to ALL for their suggestions and tips.
dogtop

A few other manufacturers of oil circulating heaters (TCU's actually): HEAT, Inc., Budzar, Mokon. All reliable and helpful vendors. You might just have a conversation with a couple of them.

Dogtop,

One kilogram per day is an extremely small production rate.

We would consider this bench scale not pilot plant.

Is this batch or continuous?

I will assume it is batch and you are heating a liquid with say a heat capacity of 1 (a hydrocarbon would be less) from ambient then your total heat load is:

Q= m*Cp*?T =2.2*1*(250-70) = 396 BTUs per day which is miniscule for a hot oil heating system.

With a desired temperature of 250°F 100 psig saturated steam has a temperature of 338°F and 50 psig saturated steam has a temperature of 287°F

Can you use steam to heat your material?  Do you have steam at your facility?

For the heat exchanger I would jacket a 1/4" stainless tube with a 1" pipe and make a tiny heat exchanger to heat the material as it flows to the reactor. A second thought is to just heat a small jacketed reaction vessel and only heat after the material has been added to the reactor.

The cost of a hot oil system may be more than your whole project.

Steam is safer by far than hot oil.  Dowtherm G, a popular heat transfer oil, has a fire point of 262°F.  If it leaks out of a flange or screwed connection and the fluid is above the fire point it catches on fire as soon as it comes in contact with air.

The fire point is the temperature at which the flame becomes self-sustained so as to continue burning the liquid (at the flash point, the flame does not need to be sustained). The fire point is usually a few degrees above the flash point.

The recirculating tanks in hot oil systems are normally blanketed with inert gas for fire protection.

I hope this helps.

Rocky Costello, P.E.
www.rccostello.com

Yes I certainly would be curious to know if this is batch or continuous myself. Coming from the fine chemical arena, I automatically assumed he was talking about a batch reactor with a volume say, 50L, which is typical for a batch yield of 1 kg of a solid product such as a crystalline pharmaceutical.

Rocky, I did want to reply to a couple of things. The fire point is in fact the point at which a flammable mixture of the vapors in air will undergo sustained combustion, ONCE IGNITED by some ignition source. But the point at which a substance will spontaneously ignite on contact with air is the Autoignition Temperature (AIT). This is much higher than 262°F for Dowtherm.

The reason many hot oil systems are blanketed with nitrogen is because many sythentic heat transfer fluids oxidize and form sludge in the presence of oxygen at high temperatures.

Dear ALL,

As ALL of you might surmise, this is a SECRET process. However, I can disclose that it is, indeed, continuous. The reactor is about 1 to 2 liters capacity. I cannot use water, steam, or anything that has H2O in their molecule. It is a high yield reaction. No, I do not need 50L to make 1 kilo of useful material.

Thanks for all your contributions. Certainly it has given me more things to think about.

Happy Holidays,

dogtop