Potassium Capture by Kaolin, Part 1: KOH

Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao; Frandsen, Flemming; Sander, Bo; Glarborg, Peter

doi:10.1021/acs.energyfuels.7b03645

Cited by 36 publications

(102 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[28]. In the raw kaolinite, Si atoms were assigned to a Q 3 Table 3, more than 80% of kaolinite-characterized Si was converted for flash calcination. The formation of mullite-characterized Si appeared at 1200 • C, in agreement with the result of XRD.…”

Section: Coordination Change Of Si and Almentioning

confidence: 99%

“…Coal, biomass and solid waste contain Na, K, Pb, Cd and other alkali/heavy metals. During combustion, gasification and other processes, these semi-volatile metals are prone to cause the problems such as boiler slagging, ash deposition of heat transfer area, high-temperature corrosion, and emissions of heavy metals and ultra-fine particles [1][2][3][4][5]. Kaolinite can adsorb alkali/heavy metal vapor at high temperatures, and then be captured by dust removal equipment [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…The furnace temperatures for coal combustion and waste incineration are 1200-1500 • C and 800-1200 • C respectively, indicating that kaolinite would change to meta-kaolinite and even mullite in the furnace according to the transformation temperature mentioned above [3]. According to the theoretical calculation, Wang et al found that the structural distortion of kaolinite for dehydroxylation has a decisive influence on its performance of metal vapor adsorption [9,10].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dehydroxylation and Structural Distortion of Kaolinite as a High-Temperature Sorbent in the Furnace

Cheng

Xing

et al. 2019

Minerals

View full text Add to dashboard Cite

As a high-temperature sorbent, kaolinite undergoes the flash calcination process in the furnace resulting in the dehydroxylation and structural distortion, which are closely related to its heavy metal/alkali metal adsorption characteristics. We investigated the flash calcination of kaolinite by the experiments using a drop tube furnace and by the characterization of flash-calcined products using thermogravimetric-differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD), Fourier Transform Infrared Spectrometer (FTIR)and nuclear magnetic resonance (NMR). There were three kinds of hydroxyl groups in kaolinite during flash calcination at 800–1300 °C, E-type (~50%, easy), D-type (~40%, difficult) and U-type (~10%, unable) according to the removal difficulty. The hydroxyl groups activation was believed to be the first step of the removal of E-type and D-type hydroxyl groups. The kinetics model of dehydroxylation groups at 900–1200 °C was established following Arrhenius equation with the activation energy of 140 kJ/mol and the pre-exponential factor of 1.32 × 106 s−1. At 800 °C, the removal of E-type hydroxyl groups resulted in the conversion of a part of VI-coordinated Al in kaolinite to V-coordinated Al and the production of meta-kaolinite. When the temperature rose up to 1200 °C, mullite was produced and a part of V-coordinated Al converted to IV-coordinated Al and VI-coordinated Al. Finally, the adsorption characteristics of kaolinite was discussed according to the results of dehydroxylation and structural distortion.

show abstract

Section: Coordination Change Of Si and Almentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dehydroxylation and Structural Distortion of Kaolinite as a High-Temperature Sorbent in the Furnace

Cheng

Xing

et al. 2019

Minerals

View full text Add to dashboard Cite

show abstract

“…A large number of studies have indicated that the main source of element K in heating surface deposits is gas phase K in biomass combustion [4,5,[8][9][10]. In this study, with the condition of combustion temperature (800 °C) and low Cl content in fuel, K probably enters the gas phase mainly in the form of KOH in place of KCl and K2SO4.…”

Section: Migration and Deposition Of Alkali Metalmentioning

confidence: 77%

“…The dominant elements in biomass ash are Ca, K, Cl and S [2,3]. During combustion, K element in biomass fuel is released to the gas phase in the form of KCl, KOH and K 2 SO 4 [4][5][6][7][8][9][10]. These potassium-containing compounds cause severe slagging due to their low melting temperature [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Ash Deposition Dynamic Process in an Industrial Biomass CFB Boiler Burning High-Alkali and Low-Chlorine Fuel

Zhang

Luo

et al. 2020

Energies

View full text Add to dashboard Cite

The circulating fluidized bed (CFB) boiler is a mainstream technology of biomass combustion generation in China. The high flue gas flow rate and relatively low combustion temperature of CFB make the deposition process different from that of a grate furnace. The dynamic deposition process of biomass ash needs further research, especially in industrial CFB boilers. In this study, a temperature-controlled ash deposit probe was used to sample the deposits in a 12 MW CFB boiler. Through the analysis of multiple deposit samples with different deposition times, the changes in micromorphology and chemical composition of the deposits in each deposition stage can be observed more distinctively. The initial deposits mainly consist of particles smaller than 2 μm, caused by thermophoretic deposition. The second stage is the condensation of alkali metal. Different from the condensation of KCl reported by most previous literatures, KOH is found in deposits in place of KCl. Then, it reacts with SO2, O2 and H2O to form K2SO4. In the third stage, the higher outer layer temperature of deposits reduces the condensation rate of KOH significantly. Meanwhile, the rougher surface of deposits allowed more calcium salts in fly ash to deposit through inertial impact. Thus, the elemental composition of deposits surface shows an overall trend of K decreasing and Ca increasing.

show abstract

Additives as a fuel-oriented measure to mitigate inorganic particulate matter (PM) emissions during small-scale combustion of solid biofuels

Gollmer

Höfer

Kaltschmitt

2018

Biomass Conv. Bioref.

View full text Add to dashboard Cite

Potassium Capture by Kaolin, Part 1: KOH

Cited by 36 publications

References 74 publications

Dehydroxylation and Structural Distortion of Kaolinite as a High-Temperature Sorbent in the Furnace

Dehydroxylation and Structural Distortion of Kaolinite as a High-Temperature Sorbent in the Furnace

Investigation of Ash Deposition Dynamic Process in an Industrial Biomass CFB Boiler Burning High-Alkali and Low-Chlorine Fuel

Additives as a fuel-oriented measure to mitigate inorganic particulate matter (PM) emissions during small-scale combustion of solid biofuels

Contact Info

Product

Resources

About