Process tubes are designed for a specific pressure and temperature.
Process tubes are located in all kind of heaters and furnaces (see below type of heaters/furnaces) in the petrochemical industry to guide a gas or liquid through the radiant section. The gas or liquid absorbs enough heat to continue the process inside the process tubes.
If the process tubes are exposed to too high temperatures, overheating may occur, resulting in hot spots at the process tubes.
Types of heaters and furnaces:
• Cracking furnace
• Crude distillation unit
• Delayed coker
• Hot oil / Thermal oil / Heat transfer furnace
• Platforming furnace
• Primary reformer
• Vacuum Distillation Furnace
• Visbreaker unit
Causes of local overheating
One of the causes could be a lower gas or liquid flow rate than designed flow rate, in combination with high firing rates.
Also an improper burner flame orientation or local flame impingement on a section of the process tubes can be a cause of local overheating.
Consequences of hot spots on process tubes:
• Coke deposits inside of the process tubes.
• In worst case, emergency shutdown.
• Increase of pressure drop.
• Lifetime expectancy reduction of the process tubes.
• Possible tube burst.
How to detect hot spots on the process tubes?
Determination of the hot spots is only possible by the using a thermal camera. It’s important that the local overheating should be solved as soon as possible.
Our solution to prevent hotspots
Our Refrex® Heatshields are designed to prevent hot spots on process tubes.
The Refrex® fabric is made out of endless high temperature fibers, able to withstand the conditions in petrochemical heaters and furnaces.
The advantages of our Refrex® Heatshields are:
• Suitable up till 1.370°C.
• Reflection of almost 60% of the radiation, which results in a lower skin temperature.
• Designed with different combinations of Refrex® fabrics, including inside insulation to meet your requirements.
• Produced to fit almost every shape of process tubes, elbows, return bends and even support brackets and hangers.
• Fast delivery, as we keep the required base materials in stock.
• Provided with Refrex® tie-cords for a quick and easy installation on site and quick removal for i.e. inspection of the process tubes.