NON-UNIFORM HEAT DISTRIBUTION BEFORE THE APPLICATION
153°C AVERAGE SURFACE TEMPERATURE REDUCTION AFTERWARDS
Figure 3 IR images before (left) and after (right) in interheater #1
and removal of the tarps, a high emissivity tube coating (TC) was applied. After refractory preparation, additional cleaning, and blowdown, the tubes adjacent to the walls were protected from overspray. The result after both tube and refractory application can be found in Figure 2 . The application took only nine days, including all steps and phases. IR inspection results To accurately predict the anticipated outcomes following the application of high emissivity coatings, an infrared inspec- tion was conducted on all process tubes. This assessment was coupled with collecting process data related to heater performance. Post-application, a significant reduction in tube surface temperatures and BWTs was anticipated for
all heaters. This reduction was expected to enhance radi- ant efficiency, enabling the potential for fuel savings or an increase in capacity under the same firing rate. Figure 3 demonstrates a substantial reduction in tube surface temperatures (averaging more than 100°C) fol- lowing the turnaround, particularly in the context of fuel savings. Furthermore, the temperature distribution along the length of the tubes became more uniform. The deter- mination of tube metal temperature via IR thermography is notably more reliable after coating application, as the oxi- dation scale is eliminated, and the coating’s emissivity and temperature gradient are well-defined. Visual inspection results Following the completion of the project, a visual inspection
Figure 4 Uncoated cell (left) vs coated (right)
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Revamps 2023
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