High-temperature corrosion due to lead chloride mixtures simulating fireside deposits in boilers firing recycled wood

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Kinnunen H, Lindberg D, Lauren T, Uusitalo M, Bankiewicz D, Enestam S, Yrjas P
Publisher: ELSEVIER SCIENCE BV
Publication year: 2017
Journal: Fuel Processing Technology
Journal acronym: FUEL PROCESS TECHNOL
Volume number: 167
Start page: 306
End page: 313
Number of pages: 8
ISSN: 0378-3820


Abstract

One of the biggest operational concerns in recycled wood combustion, is the risk for formation of low melting, corrosive deposits. The deposits present on low-temperature heat transfer surfaces (material temperature < 400 degrees C) are composed of alkali metals, chlorine, sulphur, heavy metals or, as is often the case, a mixture of these. K2SO4 is commonly regarded as non-corrosive, but there have been indications that K2SO4 may worsen the PbCl2 induced corrosion. Consequently, a more detailed study with these compounds was of very high interest. This paper reports the results obtained from 24-hour isothermal laboratory corrosion tests with PbCl2 mixed with either K2SO4 or SiO2. The tests were carried out at 350 degrees C using low alloy steel (16Mo3). The interaction between PbCl2 and K2SO4 was investigated in a furnace with a temperature gradient.As a result, a mixture of PbCl2 and K2SO4 is more corrosive than PbCl2 mixed with SiO2. Corrosion was noticed below the deposit's first melting temperature. However, for a mixture of FeCl2, KCl and PbCl2, the first melting temperature is below 350 degrees C which could explain the high oxidation rate observed below the first melting temperature of the deposit. A solid phase or a mixture of phases with the composition of K3Pb2(SO4)(3)Cl was observed in the tests with SEM/EDX for the first time. (C) 2017 Elsevier B.V. All rights reserved.


Keywords

Furnace wall, Lead potassium chloride, Superheater, Waste wood combustion

Last updated on 2019-19-06 at 04:30