1. ABSTRACT

A composite tube consists of a corrosion resistant outer layer (stainless steel or Ni-base alloy) and a pressure-vessel approved inner layer (carbon or low Cr-Mo steel). Examples of positions within waste incineration boilers where composite tubes are used are furnace wall, screen, evaporator and superheater. A number of field tests and full-scale installations of composite tubes have been evaluated and compared to tubes normally used in such applications. The experience indicates that composite tubes, compared with carbon or low alloyed tubing, prolong the tube lifetime with a factor between 2 and 20.