Is your fired heater limited by bridge wall temperature, tube metal temperature or firing duty? The cause could be excessive fouling/scale formation on the radiant tubes.
Cetek’s Tube-Coat service addresses all these issues and brings the tubes back to an as-new condition. The High Emissivity Ceramic Coatings ensure that the tubes remain in this clean state for an extended period of time.
Cetek Ceramic Coatings provide a durable, protective, thin-film layer on the outer surfaces of process tubes, which prevents oxidation, corrosion, and carburization of the metal and maintains the tube thermal conductivity coefficient close to new tube conditions.
Oxidation and scale formation on the outer surfaces of process tubes reduces conductive heat transfer, resulting in low production rates and/or excessive fuel consumption. Cetek’s High Emissivity Ceramic Coating system ensures maximum conductive heat transfer for the process.
Layers of fouling/scale prevent accurate determination of tube metal temperature, reducing the reliability of those measurements. Because the thin layer of Ceramic Coating provides a consistent temperature differential between the outside surface and the metal tube, the reliability of tube metal temperature determination is improved significantly.
Cetek’s coatings provide significant benefits in the form of:
Oxidation and scale formation on the outer surfaces of process tubes reduces conductive heat transfer, resulting in low production rates and/or excessive fuel consumption.
Cetek’s High Emissivity Ceramic Coating system ensures optimum maximum conductive heat transfer for the process.
An industry trend to operate fired heaters more efficiently, at lower excess oxygen levels, to save fuel and reduce CO2 emissions has increased the potential for carburization of external surfaces of radiant section tubes.
This leads to grain boundary penetration of carbon, carbide formation, embrittlement of the surface, crack formation and loss of metal.
The result is a reduced service life of the radiant tubes.
Radiant tube external surfaces were protected from carburization by Cetek Ceramic Coatings in applications in major refineries in Asia Pacific and India.
In each case, the life of the coating was at least 10 years, during which time there was no evidence of carburization.
If process tube life is limited by wall thickness reduction caused by oxidation or carburization, Cetek’s High Emissivity Ceramic Coatings will overcome this limitation and extend tube life.
Measuring tube metal temperatures is vital to the reliable operation of fired heaters. The presence of oxidation and layers of scale on the tube surfaces interferes with the accurate determination using IR thermography, or optical pyrometers, since the external surface of the fouling layer could be significantly higher than the actual metal temperature.
Cetek’s high emissivity ceramic coatings prevent oxidation and scale formation and provide a consistent temperature gradient between the coating surface and the metal. This allows an accurate determination of the actual metal temperature and a return to reliable operation.
The coatings are applied by Cetek’s highly trained, experienced technicians, following thorough cleaning of the tube surfaces. Coating systems are available for every type of metal substrate and process temperature.
The coating application may be applied in-situ, to tubes already installed in heaters, or to new tubes at Cetek’s facility, or at a remote site. In the latter cases, coated tubes may be placed in storage until needed.
The coatings are inert, non-catalytic, and water-based, offering a complete environmentally safe process improvement.
The service is supported by a superior Health & Safety Program, yielding a safety record better than industry standards.
