Letter 33068

Teflon coating of heat exchangers [Maine]  

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I am doing my project on coating a heat exchanger with Teflon to make it corrosion resistant. The heat exchanger will be used in oil & gas or petroleum industry.

The conditions are: approx. 160 o C temperature, untreated water, H2S gas inside the tube while water is outside the tube to cool the gas. The pressure inside the tube is around 1282 psi. The heat exchanger weighs around 4.5 ton.

Could anybody please tell me whether I can use Teflon coating for such application and if I can then what process I can use? Thanks Cathy

Catherine Hunt
Student - Auburn, Maine, U.S.A

For safety reasons it would not be a good idea to coat pipes with a thin layer of Teflon which might separate from the basis and loose its imperviousness and expose the metal. Thick coatings as well as solid Teflon would impede the primary function of a heat exchanger due to the poor heat transfer of all plastics. In summary, I think you selected a very difficult application or project.

Guillermo Marrufo
Monterrey, NL, Mexico

If you are allowed to change the focus of your assignment, anodized aluminum makes great heat exchangers, especially in water cooled applications. "The Surface Treatment and Finishing of Aluminum and Its Alloys" goes into the details of why it works so well; second volume, mid-way or so...

The oxide coating formed by anodizing would also increase corrosion resistance.

Jim Gorsich Accurate Anodizing Inc. Compton, CA, USA

Well...some companies are making all-Teflon heat exchangers. I wonder how they dealt with the heat transfer issues. But I think if coating is thin enough then heat transfer wouldn't be a problem. And if coating is done well then it will protect it fairly.

Catherine Hunt
- Auburn, Maine, U.S.A

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