Chemical cleaning is an effective measure to solve the frequent over temperature problem of superheater. By taking the T91 heat exchange tube of final stage superheater of a supercritical 660 MW unit as the research object

both theoretical analysis on actual operation of the boiler and numerical simulation using ANSYS software were carried out to investigate the heat transfer process of the final stage superheater's tube. Moreover

the wall temperature distribution of the final superheater tube before and after the chemical cleaning were studied. The results show that

higher boiler load and thicker oxide scale caused higher tube temperature. Chemical cleaning can significantly improve heat transfer performance of the tube and effectively reduce temperature difference between and among the final stage superheater tube panels.