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How to screen high temperature steels for optimal use in biofuel-heated burners for residential boilers: Role of alkali

R. Pompe ; C. Pettersson ; Jan-Erik Svensson (Institutionen för kemi- och bioteknik, Oorganisk miljökemi) ; Lars-Gunnar Johansson (Institutionen för kemi- och bioteknik, Oorganisk miljökemi)
NACE - International Corrosion Conference Series. Corrosion 2011, Houston, United States, 13-17 March 2011 (0361-4409). p. 12p. (2011)
[Konferensbidrag, refereegranskat]

Hot parts of burners for residential boilers are subject to irregular heating cycles up to 800 °C and higher, simultaneously exposed to alkali salts, variable oxygen partial pressure - and thermal shock. Fundamental hot corrosion studies under well-controlled conditions, in combination with simple ranking tests simulating the effect of ash deposited on the alloy surface, have been performed. The investigation included four types of high-alloyed steel and two types of ash from wood and bark pellets. The work was complemented with field studies of selected damaged parts. Two mechanisms involving interaction of potassium as well as carbon under intermittent oxygen-deficient conditions with chromium from the alloys have been corroborated. A simple ranking test procedure has also been designed. It proved relevant as a screening method only after incorporating a mild thermal shock in the heat treatment sequence. A significant difference in corrosive effect, particularly on a lower chromium-alloy like 304 L, has been observed for the ash derived from the wood and bark pellets, respectively.

Nyckelord: Alkali corrosion, High temperature corrosion-resistant alloys, Pellet ash, Residential boilers, Screening, Thermal shock



Denna post skapades 2015-05-06. Senast ändrad 2016-07-21.
CPL Pubid: 216628

 

Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Oorganisk miljökemi (2005-2014)

Ämnesområden

Kemi

Chalmers infrastruktur