Improve performance by increasing heat radiation from the outer tube? The reason I ask is that it seems to be really working hard during methanol recovery either from biodiesel or glycerin.

At the end of a couple hours of ingesting 150-160F methanol laden fumes the cooling water is reading about 100F or above. The temperature drop across the condenser from intake to exhaust is between 10 and 20 degrees F.

I've painted engines that I've built flat black to increase heat loss via the surface of the engine, I wonder, would it apply in this case as well?

If it's presently shiny silver then painting it black will significantly improve heat radiation. If it's dull tarnished copper then don't expect much improvement. It's directly related to the emissivity of the surface. You can Google to find relative emissivities of materials.

Ok, that's good to know. As it stands now the copper outer surface is rather tarnished. I guess a coat of Krylon flat black wouldn't hurt either.

Regardless of the heat loss, flat black will make it look cool.
Decreasing cooling water temperature, or increasing flow, will probably have a greater effect.

I got plenty of intimidation points at the dragstrip with my flat black painted engines.

Update:

I painted the outside of the condenser with flat black Krylon. Now this is rather empirical, but I did notice a higher temperature on the outside of the condenser in relation to the black tape I had on the outside previously for temperature measurement.

Also, the amount of methanol coming from the output seemed to be greater. I also noticed a greater delta T between the cooling water intake and exhaust. Before I was running about a 10 degree increase across the condenser, now I'm seeing a delta T of around 20 degrees.

So something is working. Not sure exactly what, but I'll take it. Everything was going swimmingly until the 600V contactor in my brainbox went south on me and now I have to wait until Sunday or Monday to wire in a replacement.

is it possible to replace the contactor( mechanical relay) with an SSR?

I replaced my HVAC relays last year. other than some bad solder joints (didn't clean the old switch post well enough) no problems..

an SSR should if rated correctly and cooled properly..last 1000X the switching cycles of a mechanical contactor.

just a thought

-dkenny

quote:

is it possible to replace the contactor( mechanical relay) with an SSR?

Yep, without question. They are more likely to fail in the closed position though. I would recommend using a highlimit control that will open a separate contactor to kill the heater.
If you are using a PID it will likely have a parameter to select the output from an SSR or contactor.
For the ultimate in reliability a mercury contactor is the most robust and unlikely to weld shut...
Jon

Update:

Turned out it wasn't the contactor, although it did need replacing. There was a wire that was grounding to the outside of the reactor tank. I've since rewired the unit externally with EMT and the appropriate fittings for safety.