Metal finishing Q&As since 1989

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Black Oxide tank heating problem

We have a Black oxide tank made of mild steel and we heat the solution with the under-fired method, using a commercial burner like the ones used for cooking
We know this is the simplest and oldest method of heating industrial process tanks utilizing gas and we want to improve the installation as well as reduce Gas usage.
I'm the maintenance employee and I'd like to know what method has been proved to be more friendlier to use and more efficient.
We heard there are small diameter immersion tube gas burners, do anyone use them? What are the advantages or what method is recommended.

Thank you for your help

Sergio

Sergio Hernandez
plating shop employee - Guadalajara, Mexico
September 15, 2011

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September 20, 2011

I do not like them as they tend to erode at the hottest part which is the entry point if you use a thru the wall installation.

I would switch to a heater like you find in gas grills. They are set for propane, but it is a minor mod to have them run on methane.

I added a outer wall for the heat to rise in close contact to the wall for additional heating from the same amount of gas.

Mine was a 12 x 18 x 30 inch local made tank.

James Watts
- Navarre, Florida

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Full length pipe burners are generally the best for even heating and skirting the tanks properly will cut your heat consumption almost in half. The distance from the skirt to the wall should be an inch or two with the skirt sealed at the top against the tank. Skirts normally hang an inch or two below the tank. The solution level should always be even or slightly higher than the top of the skirt to prevent warping the tank. Also your pipe burner should be below the skirt of your tank by a couple inches to prevent overheating the burner. A lot of people here convert their systems to natural gas to save money. Its is a simple air mix change to make them burn properly just like in a gas stove. I know some people that have gone to electric, in-tank heaters and they are nice to use with little steaming or heat give off which cuts back on ventilation but decidedly more expensive to operate.

Rod Henrickson
gunsmith - Edmonton, Alberta, Canada
September 22, 2011

adv.