The behavior of inorganic material in biomass-fired power boilers: field and laboratory experiences

Baxter, Larry; Miles, T. R.; Jenkins, Bryan M.; Milne, Thomas A.; Dayton, David C.; Bryers, R. W.; Oden, L.L.

doi:10.1016/s0378-3820(97)00060-x

Cited by 582 publications

(389 citation statements)

References 6 publications

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“…In the gas phase, K is mainly present as KCl and KOH. KCl is dominant when the Cl content in the fuel mix is high [3,4]. Chlorine is mainly released as hydrogen chloride (HCl) or as metal chlorides, such as KCl.…”

Section: Introductionmentioning

confidence: 99%

The effect of oxygen and volatile combustibles on the sulphation of gaseous KCl

Kassman

Normann

Åmand

2013

Combustion and Flame

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a b s t r a c tSulphur/sulphate containing additives, such as elemental sulphur (S) and ammonium sulphate (NH 4 ) 2 SO 4 ), can be used for sulphation of KCl during biomass combustion. These additives convert KCl to an alkali sulphate and a more efficient sulphation is normally achieved for ammonium sulphate compared to sulphur. The presence of SO 3 is thus of greater importance than that of SO 2 . Oxygen and volatile combustibles could also have an effect on the sulphation of gaseous KCl. This paper is based on results obtained during co-combustion of wood chips and straw pellets in a 12 MW circulating fluidised bed (CFB) boiler. Ammonium sulphate was injected at three positions in the boiler i.e. in the upper part of the combustion chamber, in the cyclone inlet, and in the cyclone. The sulphation of KCl was investigated at three air excess ratios (k = 1.1, 1.2 and 1.4). Several measurement tools were applied including IACM (on-line measurements of gaseous alkali chlorides), deposit probes (chemical composition in deposits collected) and gas analysis. The position for injection of ammonium sulphate had a great impact on the sulphation efficiency for gaseous KCl at the different air excess ratios. There was also an effect of oxygen on the sulphation efficiency when injecting ammonium sulphate in the cyclone. Less gaseous KCl was reduced during air excess ratio k = 1.1 compared to the higher air excess ratios. The optimal position and conditions for injection of ammonium sulphate were identified by measuring KCl with IACM. A correlation was observed between the sulphation of gaseous KCl and reduced chlorine content in the deposits. The experimental observations were evaluated using a detailed reaction mechanism. It was used to model the effect of volatile combustibles on the sulphation of gaseous KCl by SO 3 . The calculations supported the proposition that the presence of combustibles at the position of SO 3 injection (i.e. AS) causes reduction of SO 3 to SO 2 .

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Section: Introductionmentioning

confidence: 99%

The effect of oxygen and volatile combustibles on the sulphation of gaseous KCl

Kassman

Normann

Åmand

2013

Combustion and Flame

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“…This is due to an aggressive environment that contains e.g. alkali salts and water combined with metal temperatures up to *550°C [1][2][3][4][5][6][7][8][9]. At such relatively low temperatures, chromia-forming alloys, such as FeCr and FeCrNi steels, are currently being used [10].…”

Section: Introductionmentioning

confidence: 99%

KCl-Induced Corrosion of an FeCrAl Alloy at 600 °C in O2 + H2O Environment: The Effect of Pre-oxidation

et al. 2014

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The present study investigates the influence of H 2 O and KCl on the high temperature corrosion of an FeCrAl alloy at 600°C. Polished samples were exposed to O 2 or O 2 ? H 2 O and to O 2 ? H 2 O with KCl applied. The samples were investigated using SEM/EDX, XRD, IC, AES and SIMS. It was found that KCl accelerates corrosion and that a rapidly growing iron-rich oxide forms with time. Chromate formation is shown to initiate the formation of a non-protective oxide scale. Pre-oxidising the alloy before exposure in the presence of KCl had a strongly beneficial effect on the corrosion.

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“…Burning biomass and waste results in a more corrosive fireside environment, e.g., it contains more alkali chloride than fossil fuels [1][2][3][4][5][6][7][8][9]. Consequently, the corrosion of critical components in a power boiler, e.g., the superheater tubes, is a major challenge.…”

Section: Introductionmentioning

confidence: 99%

Cyclic Corrosion and Chlorination of an FeCrAl Alloy in the Presence of KCl

et al. 2015

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The KCl-induced corrosion of the FeCrAl alloy Kanthal Ò APMT in an O 2 ? N 2 ? H 2 O environment was studied at 600°C. The samples were pre-oxidized prior to exposure in order to investigate the protective nature of alumina scales in the present environment. The microstructure and composition of the corroded surface was investigated in detail. Corrosion started at flaws in the pre-formed a-alumina scales, i.e. a-alumina was protective in itself. Consequently, KCl-induced corrosion started locally and, subsequently, spread laterally. An electrochemical mechanism is proposed here by which a transition metal chloride forms in the alloy and K 2 CrO 4 forms at the scale/gas interface. Scale de-cohesion is attributed to the formation of a sub-scale transition metal chloride.

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The behavior of inorganic material in biomass-fired power boilers: field and laboratory experiences

Cited by 582 publications

References 6 publications

The effect of oxygen and volatile combustibles on the sulphation of gaseous KCl

The effect of oxygen and volatile combustibles on the sulphation of gaseous KCl

KCl-Induced Corrosion of an FeCrAl Alloy at 600 °C in O2 + H2O Environment: The Effect of Pre-oxidation

Cyclic Corrosion and Chlorination of an FeCrAl Alloy in the Presence of KCl

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