Reduction of superheater corrosion by co-firing risky biomass with sewage sludge

“…Various technologies for reducing ash deposition as well as corrosion have been studied. These include: (1) [10,20,41,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76]; (2) co-firing bio-fuels with low fouling-tendency fuels [8,55,[77][78][79][80][81]; (3) pretreatment of the feedstock to reduce the alkali metals [82,83], and (4) modification of the boiler (e.g., modification of the re-heater and super-heater in order to allow for larger spacing, more soot-blowing and a decrease in the live steam temperature to less than 500 °C, etc.) [60].…”

Section: Technologies For Reducing Ash Deposition and Corrosionmentioning

confidence: 99%

“…As kaolinite and other aluminosilicates are abundantly present in most coals [87], it is likely that an alkali absorption mechanism is active during the co-combustion. Moreover, some biofuels such as sewage sludge contain different aluminum silicates, silica and alumina, which could increase biomass ashes sintering temperatures and reduce their fouling deposition in various studies [77][78][79][80].…”

Section: Co-firing Biomass With Low Fouling-tendency Fuelsmentioning

confidence: 99%

Ash Deposition in Biomass Combustion or Co-Firing for Power/Heat Generation

et al. 2012

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This paper presents a concise overview of ash deposition in combustion or co-firing of biomass (woody biomass, agricultural residues, peat, etc.) with other fuels for power/heat generation. In this article, the following five research aspects on biomass combustion ash deposition are reviewed and discussed: influence of biomass fuel characteristics, deposit-related challenges, ash deposition monitoring and analysis of ash deposits, mechanisms and chemistry of fly ash deposition, and key technologies for reducing ash deposition and corrosion in biomass-involved combustion.

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“…In particular, this means avoiding the build-up of deposits rich in alkali chlorides. It has been demonstrated that deposit formation and superheater corrosion can be counteracted by co-combustion with sulphur-containing fuels or additives [14][15][16][17][18][19][20][21]. With a sufficient concentration of sulphur in the fuel, the alkali chloride can be converted into a less corrosive alkali sulphate (K 2 SO 4 ).…”

Section: Introductionmentioning

confidence: 99%

“…With a sufficient concentration of sulphur in the fuel, the alkali chloride can be converted into a less corrosive alkali sulphate (K 2 SO 4 ). Coal, peat and municipal sewage sludge are examples of fuels suitable for co-combustion with biomass [14][15][16]21], whereas elemental sulphur (S) and ammonium sulphate ((NH 4 ) 2 SO 4 , AS) are commonly used sulphur-based additives [14,[18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Deposit chemistry and initial corrosion during biomass combustion – The influence of excess O₂ and sulphate injection

Viklund

Kassman

Åmand

2014

Materials & Corrosion

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Corrosion of superheater tubes is a serious problem during combustion of fuels with a high content of chlorine, such as waste and certain biomasses. The alkali chlorides are released to the flue gas and may condense on the heat exchanger tubes forming corrosive, chloride-rich deposits. In this work the effect of ammonium sulphate ((NH 4 ) 2 SO 4 ) injection on gaseous alkali chlorides, deposit chemistry and initial corrosion attack of superheater tubes during biomass combustion have been investigated. The investigation was carried out at three different sulphate injection rates (reference, low and high) and at three air excess ratios ( ¼ 1.1, 1.2 and 1.4). Short-term exposures of Sanicro 28 specimens, using temperature controlled probes, were used for deposit collection and to study the initial corrosion attack. The results showed reduced concentrations of potassium chloride in the flue gas when injecting ammonium sulphate and in particular in combination with high air excess ratios. A decrease of chlorine was also observed in the deposit, but the concentrations did not always correlate to the flue gas measurements. In particular, it was evident that a subsequent sulphation occurred on the tube surface at low air excess ratios. Metallography revealed that sulphation reactions on the tube surface, rather than in the flue gas, had a detrimental effect on the initial corrosion attack. As a consequence, the corrosion attack correlated more clearly to the KCl(g) concentration in the flue gas than the chlorine content in the deposit.

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Reduction of superheater corrosion by co-firing risky biomass with sewage sludge

Cited by 71 publications

References 17 publications

Corrosion in biomass combustion: A materials selection analysis and its interaction with corrosion mechanisms and mitigation strategies

Corrosion in biomass combustion: A materials selection analysis and its interaction with corrosion mechanisms and mitigation strategies

Ash Deposition in Biomass Combustion or Co-Firing for Power/Heat Generation

Deposit chemistry and initial corrosion during biomass combustion – The influence of excess O₂ and sulphate injection

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Reduction of superheater corrosion by co-firing risky biomass with sewage sludge

Cited by 71 publications

References 17 publications

Corrosion in biomass combustion: A materials selection analysis and its interaction with corrosion mechanisms and mitigation strategies

Corrosion in biomass combustion: A materials selection analysis and its interaction with corrosion mechanisms and mitigation strategies

Ash Deposition in Biomass Combustion or Co-Firing for Power/Heat Generation

Deposit chemistry and initial corrosion during biomass combustion – The influence of excess O2 and sulphate injection

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Product

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Deposit chemistry and initial corrosion during biomass combustion – The influence of excess O₂ and sulphate injection