What is in this article?:
- Turning Up The Heat On Thermal Processes
- No-Compromise Improvement
Ceramic materials can significantly improve gas-to-gas shell and tube heat exchangers’ performance and operating cost.
- Ceramic versus metal
- Defining material characteristics
- Silicon carbide and other forms
A view inside a seven-tube test fixture, while testing seals for pressurized tubes. The tubes can be seen glowing a 1,800°F.
Gas-to-gas shell and tube heat exchangers and ceramic materials … none of these is too exciting, but when successfully combined into one product they can significantly improve your process and positively impact your bottom line.
We’re all familiar with heat exchangers; there is at least one in every car. You’ll see them spewing steam on the side of the road in the summertime. They are more typically referred to as radiators, but in fact they are heat exchangers. While simple and comparatively cheap, radiators get the job done. And if you are lucky, you will never have to drain the nauseously sweet smelling and slimy fluid from one to replace a worn out or damaged radiator.
But, when that same technology is applied to a demanding industrial process, replacing or rebuilding heat exchangers becomes a capital expense that hits your bottom line, time and time again.
Similarly, if you have ever cooked on a pizza stone or changed your own spark plug, you’ve used or at least been exposed to ceramic materials. Now, the ceramics to be described here are different in composition, shape, and application, but of the same category of refractory materials.
Ceramics are used in numerous applications: They allow us to run thermal processes at higher temperatures and in severely corrosive and abrasive environments. They can be great thermal conductors, but also great thermal and electric insulators. Compared to metal, a properly selected ceramic will outperform in any thermal application while reducing or eliminating concerns of corrosion, erosion, oxidation and thermal degradation. Replacing metal components with ceramics can significantly reduce downtime due to material failure, while increasing efficiency and process operating temperatures.
Metal heat exchangers have been around for over a century, and are proven devices in many industries. As processes and technology have improved, the metal heat exchanger has been pushed to its limits and beyond. The costly exotic materials that must be used at higher temperature, and often times corrosive environments, drive up costs and still sacrifice durability in these harsh environments.
Due to the wide variation in these processes, metals also are very difficult to select. For instance, a metal that has great creep strength at elevated temperatures may be very poor at resisting certain acid attacks. Another metal that has good resistance to acids may not perform in an erosive environment. Often, compromises have to be made for the materials of construction in metal heat exchangers.