THE APPLICATION OF TRANSIENT THERMOGRAPHY TO THE INSPECTION OF PROTECTIVE COATINGS IN FGD PLANT

Corrosion and erosion resistant materials are being applied to protect the steelwork in the ducts and scrubber towers which comprise the Flue Gas Desulphurisation (FGD) plant currently under construction by PowerGen at Ratcliffe-on-Soar Power Station. Tens of thousands of square meters are being coated which presents a large challenge for existing inspection techniques. The use of thermal imaging cameras and heating sources which cause thermal energy to propagate through the coating to reveal underlying defects has been investigated in the laboratory, and on the FGD plant. The results show that the transient thermography technique can find areas of disbonding between coating and steel as well as small pores, and is therefore a solution which will provide a rapid, whole area inspection, thereby reducing the probability of an unplanned shutdown due to a coating failure.