Installation and operation of titanium liners in FGD ductwork and stacks
D. Peacock
CICIND REPORT Vol. 12, No. 1, 1996
Order No: CR-086
The paper discusses the advantages and limitations of titanium as a chimney liner material. An important limitation described in detail is its unsuitability for conditions where active fluorides or hot concentrated reducing acids can be generated, e.g. in incinerators. Titanium can not be welded to steel, so "Resista-Clad" had been developed to permit application by wall-papering to a carbon steel base. "Resista-Clad" comprises thin titanium sheets, supplied attached to a backing strip of carbon steel, capable of being welded to the base liner.
The paper also describes the selection and application procedures for the titanium lining applied to the existing three elliptical concrete liners in the 260m tall chimney during retrofitting FGD at Drax Power Station - the largest in the world. Prior to retrofitting FGD, the liners had been protected for a number of years by a fluorelastomer coating (Colebrand CXL2000), but it was thought this material would be unsuitable in an FGD environment..
The material and design selection for Drax involved examination (described in detail) of the performance of titanium liners at various power stations in the USA. A technique was developed for mechanical attachment of each titanium plate to these concrete liners, applied as tiling on a bedding grout of fluopolymeric mastic. Lining the first flue (involving 8000 sheets of titanium) took just 23 days. This was reduced to 19 days for the final flue - an important consideration, as the necessary outage of this base load station was very expensive.