Sulfation of corrosive alkali chlorides by ammonium sulfate in a biomass fired CFB boiler

Broström, Markus; Kassman, Håkan; Helgesson, Anna; Berg, Mats; Andersson, Christer; Backman, Rainer; Nordin, Anders

doi:10.1016/j.fuproc.2007.06.023

Cited by 128 publications

(75 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The corrosivity of alkali chlorides towards stainless steels at high temperature is well documented [9][10][11][12][13][14][15][16]. Hence, several attempts have been made to mitigate corrosion in the boilers by changing the chemistry of the fireside environment so as to suppress the formation of alkali chloride deposits [5,6,[17][18][19]. These attempts have had some success.…”

Section: Introductionmentioning

confidence: 99%

The Effects of KCl, K2SO4 and K2CO3 on the High Temperature Corrosion of a 304-Type Austenitic Stainless Steel

et al. 2011

View full text Add to dashboard Cite

The oxidation of 304-type (Fe18Cr10Ni) austenitic stainless steel was investigated at 500 and 600°C in 5% O 2 ? 40% H 2 O. Prior to exposure the samples were sprayed with KCl, K 2 CO 3 or K 2 SO 4 , the amount of salt corresponding to 1.35 lmol K ? /cm 2 . For reference, salt-free samples were exposed in 5% O 2 ? 40% H 2 O and in 5% O 2 (N 2 was used as carrier gas). The oxidized samples were analyzed with SEM/EDX, XRD, IC and FIB. KCl and K 2 CO 3 strongly accelerate the corrosion of 304L while K 2 SO 4 has little influence on the corrosion rate and on the morphology of the corroded surface. KCl and K 2 CO 3 react with the chromium-rich oxide on the sample surface, forming K 2 CrO 4 . The resulting chromium depletion of the protective oxide causes rapid oxidation and the formation of a thick duplex scale consisting of an outer hematite layer and a inner layer made up of FeCrNi spinel-type oxide. The differences in the corrosivity of the three salts are directly connected to their ability to form chromate on the surface and, hence, to the relative stability of the corresponding leaving groups (HCl, CO 2 and SO 3 ).

show abstract

Section: Introductionmentioning

confidence: 99%

The Effects of KCl, K2SO4 and K2CO3 on the High Temperature Corrosion of a 304-Type Austenitic Stainless Steel

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The effectiveness of this method at reducing the corrosion rate and deposit was confirmed by Broström et al [99]. Henderson et al [101] have also pointed out the effectiveness of this treatment at reducing chloride-induced corrosion of superheater materials in wood-fired boilers.…”

Section: Additivesmentioning

confidence: 83%

“…Additives can reduce chlorine-induced corrosion during biomass combustion by two different routes: (i) prevention of gaseous KCl release or (ii) reaction with KCl forming less corrosive species [99]. Sulfur-containing additives are suitable to this purpose as they can react with alkali chlorides yielding less corrosive alkali sulfates.…”

Section: Additivesmentioning

confidence: 99%

See 1 more Smart Citation

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

2013

View full text Add to dashboard Cite

“…19,21 Thus, for the same sulfur dosage, a significantly higher sulfation degree on alkali chlorides can be obtained with a sulfate additive as compared to elemental sulfur or SO 2 . 21,31 In spite of the extensive experimental studies on the utilization of sulfate additives, 5,9,19,[21][22][23]34 investigations on the decomposition rate and products (e.g., the distribution between the produced SO 2 and SO 3 ) of these additives are scarce. In relation to this, no modeling work has been carried out to simultaneously simulate the decomposition of the sulfate additives and the sulfation of potassium chloride under biomass-fired boiler conditions.…”

Section: Introductionmentioning

confidence: 99%

Modeling of ferric sulfate decomposition and sulfation of potassium chloride during grate‐firing of biomass

Jespersen

Frandsen

et al. 2013

AIChE Journal

View full text Add to dashboard Cite

in Wiley Online Library (wileyonlinelibrary.com) Ferric sulfate is used as an additive in biomass combustion to convert the released potassium chloride to the less harmful potassium sulfate. The decomposition of ferric sulfate is studied in a fast heating rate thermogravimetric analyzer and a volumetric reaction model is proposed to describe the process. The yields of sulfur oxides from ferric sulfate decomposition under boiler conditions are investigated experimentally, revealing a distribution of approximately 40% SO 3 and 60% SO 2 . The ferric sulfate decomposition model is combined with a detailed kinetic model of gas-phase KCl sulfation and a model of K 2 SO 4 condensation to simulate the sulfation of KCl by ferric sulfate addition. The simulation results show good agreements with experiments conducted in a biomass grate-firing reactor. The results indicate that the SO 3 released from ferric sulfate decomposition is the main contributor to KCl sulfation and that the effectiveness of ferric sulfate addition is sensitive to the applied temperature conditions. V C 2013 American Institute of Chemical Engineers AIChE J, 59: [4314][4315][4316][4317][4318][4319][4320][4321][4322][4323][4324] 2013

show abstract

Sulfation of corrosive alkali chlorides by ammonium sulfate in a biomass fired CFB boiler

Cited by 128 publications

References 5 publications

The Effects of KCl, K2SO4 and K2CO3 on the High Temperature Corrosion of a 304-Type Austenitic Stainless Steel

The Effects of KCl, K2SO4 and K2CO3 on the High Temperature Corrosion of a 304-Type Austenitic Stainless Steel

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

Modeling of ferric sulfate decomposition and sulfation of potassium chloride during grate‐firing of biomass

Contact Info

Product

Resources

About