COMBINED USE OF AN ELECTRONIC ANTIFOULING TECHNOLOGY AND BRUSH PUNCHING FOR SCALE REMOVAL IN A WATER-COOLED PLAIN TUBE

The objective of the present study was to investigate the benefit of the combined use of an electronic antifouling (EAF) technology and brush punching for scale removal in a shell-and-tube heat exchanger. Two fouling experiments were conducted with new plain tubes: one without an EAF treatment and the other with it. Scale inside the two tubes was produced in a recirculation-flow system with an artificially hardened water of 7.5 mol/m^3. Afterpassing tap water through each tube for 4 days, the fouling resistance in the tube with the EAF treatment was measured and found to be 46% less than in the one without the EAF treatment. Subsequent brush punching of the tube for the case with the EAF treatment cleaned almost all of the remaining scale, thus recovering the initial overall heat transfer coefficient values, resulting in zero fouling resistance. However, for the case without the EAF treatment, brush punching was not effective in removing scale. Both the present experiment and earlier SEMphotographs support the benefit of the combined use of the EAF technology and brush punching on scale removal in heat exchangers.