Reduction of maintenance costs in highly corrosive processes

In many chemical processes, corrosion is a big problem. The tubes and valves suffer enormous wear and the maintenance cycles are getting shorter. The cost involved in these processes is enormous, due to the high frequency of change in the facilities. The problem is not only the internal corrosion but also the external corrosion by corrosive vapors.

Last week I participated in a course on valves and pipes and I want to share what I learned in these two days ref. to this topic.

Instead of changing tubes every 3 months due to leakage problems or blocked valves due to mechanical problems, I propose the following solution:

Pipes and valves coated with polymers.

These coatings of different qualities of Teflon (PTFE, PFA, FEP), Tefzel (ETFE) or PVDF protect the tube and extend the maintenance cycle in many cases up to years. During the course I had doubts regarding two point:

1. How does a tube like this reacts, if we have a negative pressure (vacuum)?

It depends on the technology which was used during the process of the coating. There are products, where a Teflon tube or other anticorrosive materials is placed inside the metal tube. If we now have a high temperature and simultaneously there is a vacuum, bubbles are created in the coating that reduce the section of the tube up to closing it. In the case of tubes of the company HiTech, the polymers are injected after a treatment of the walls. This is how we get a perfect Teflon glue. Before submitting the product, it is subjected to a vacuum and heat test for checking purposes.

2. What actions do we take if we have an acid diffusion through the coating?

To prevent this effect there are several countermeasures based on the experience of the manufacturer:

• Increase the thickness of the coating
• Increase the crystalline part of the Teflon to cover the micro-channels.
• Create a surface that is as smooth as possible during extrusion
• Right Polymer Selection

We have at your disposal different types of tubes, valves and accessories coated with different Polymers through different coating techniques:

If you are interested in this solution, please contact us and we will talk.

Thanks for your interest.