The paper contains a survey of digesters and other pressure vessels, e.g. hot liquor tanks, accumulators and impregnation vessels, made of solid duplex stainless steel and installed in pulp cooking plants. Pressure vessels in the bleach plants, i.e. oxygen delignification reactors, peroxide and extraction reactors, are also covered by this study. In total more than 200 such pressure vessels have been identified at 43 plants in 17 countries ,all made of type 2205 material.

Most of these pressure vessels can be found in Finland and Sweden. It was possible to source information on service performance from close to 50% of the installations. Not one single case of materials related problem was reported but several very positive comments were given. The oldest installation found was two kraft pulp digesters which had been in service since 1988.

Some experience from other installations than pressure vessels, e.g. pulp storage towers and a bleach plant wash filter, was also reported.