Thermochemistry of alkali interactions with refractory adsorbents

Shadman, Farhang; Punjak, W.A.

doi:10.1016/0040-6031(88)80069-8

Cited by 18 publications

(12 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alkali capture, especially the Na-capture reaction by kaolin, has been widely studied, primarily because of its application for cleaning Na-species from hot flue gases in combined cycle gas turbine (CCGT) power plants − and for dealing with ash-related problems in combustion of Na-rich low rank coals in power plant boilers. ,− However, when it comes to biomass combustion, K-capture reaction is of greater concern, but it has been studied to a less extent …”

Section: Introductionmentioning

confidence: 99%

Potassium Capture by Kaolin, Part 1: KOH

Wang¹,

Jensen²,

Wu³

et al. 2018

Energy Fuels

View full text Add to dashboard Cite

 Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

show abstract

Section: Introductionmentioning

confidence: 99%

Potassium Capture by Kaolin, Part 1: KOH

Wang¹,

Jensen²,

Wu³

et al. 2018

Energy Fuels

View full text Add to dashboard Cite

show abstract

“…Al-Si-type additives are mostly the first choice in the literatures [61,62,[67][68][69]72] due to their strong ability for converting vapor/liquid-phase KCl and KSiO 3 to potassium aluminum silicates (e.g., KAlSiO 4 , KAlSi 2 O 6 , KAlSi 3 O 8 , etc.) with high melting-points (>1100 °C) by the reactions indicated in Equation (3).…”

Section: Addition Of Combustion Additivesmentioning

confidence: 99%

“…Use of additives to tackle the ash-related issues is mainly based on the idea of converting the vaporized inorganic species to less volatile forms, thus enhancing the melting temperature of ash residues via chemical reactions and physical interactions (i.e., absorption/dilution) [41,62,67,68] and reducing the formation of fine particles or water-soluble alkalis [84][85][86]. So far, dozens of different additives have been tested and used to increase the melting points of the alkali compounds (e.g., KCl, K 2 O, KSiO 3 , etc.)…”

Section: Addition Of Combustion Additivesmentioning

confidence: 99%

“…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%

See 1 more Smart Citation

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

et al. 2012

View full text Add to dashboard Cite

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.

show abstract

“…Aluminosilicate additives have attracted lots of scientific and industrial interests for capturing alkali salts. − Kaolin and coal fly ash (CFA) are among the most investigated aluminosilicates. The short residence time in PF boilers demands very fine particles of fuel and additives, so additive particles of micrometer’s size should be suspended in a gas environment containing vaporized alkali to simulate PF boiler conditions in experiments.…”

Section: Introductionmentioning

confidence: 99%

Modeling Potassium Capture by Aluminosilicate, Part 2: Coal Fly Ash

Hashemi

Wang²,

Jensen

et al. 2021

Energy Fuels

View full text Add to dashboard Cite

By use of coal fly ash as an additive in pulverized biomass fuel boilers, harmful alkali species can be bound in alkali alumina silicates that are less harmful. In this study, potassium scavenging by coal fly ash (CFA) at conditions of pulverized-fuel (PF) boilers was modeled. Under the investigated conditions, evaporated potassium salts were captured with suspended CFA particles. Two modeling approaches were investigated, shrinking core model (SCM) and uniform conversion model (UCM). Both approaches simulated the impacts of chemical kinetics, diffusion of gaseous salts around the additive particles, and thermodynamic equilibrium on potassium conversion. Moreover, the SCM included the diffusion resistance in a product layer around the particle. The models have been evaluated against entrained flow-reactor (EFR) measurements from the literature for capturing KOH, KCl, K2CO3, and K2SO4 by CFA. Chemical kinetic rate coefficients for the reaction between the potassium salts and CFA have been derived from the EFR data measured at relatively lower temperatures of 800–900 °C. The porosity properties of the reacted CFA were also estimated in the present work. The effects of temperature, salt concentration, and CFA particle size on the model prediction have been examined and evaluated against the experimental data. The results indicated that in most conditions, the SCM prediction is more reliable, probably due to the inclusion of diffusion resistance of a product layer around the particle. Comparing the SCM with experimental data shows that the model can reasonably predict the reaction of CFA with potassium salts at conditions investigated here: 800–1450 °C, salt to additive ratios of 0.05–0.96, and for CFA particles of 6–34 μm.

show abstract

Thermochemistry of alkali interactions with refractory adsorbents

Cited by 18 publications

References 2 publications

Potassium Capture by Kaolin, Part 1: KOH

Potassium Capture by Kaolin, Part 1: KOH

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

Modeling Potassium Capture by Aluminosilicate, Part 2: Coal Fly Ash

Contact Info

Product

Resources

About