Impact of coal fly ash addition on ash transformation and deposition in a full-scale wood suspension-firing boiler

Wu, Hao; Bashir, Muhammad Shafique; Jensen, Peter Arendt; Glarborg, Peter; Sander, Bo

doi:10.1016/j.fuel.2013.06.018

Cited by 65 publications

(122 citation statements)

References 67 publications

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“…In addition to the oxides, potassium and calcium elements form carbonates and sulfates. The potassium retained in the ash was proposed to appear as hydroxide [2] and to a minor extent as chloride due to the low concentration of chlorine [41]. With the exception of Ca 3 (PO 4 ) 2 and CaSO 4 identified here, all other compounds identified in this study have been previously detected in ash samples by Wu et al [2].…”

Section: X-ray Diffractionmentioning

confidence: 46%

“…The reactivity of char was determined using a TG instrument (Netzsch, STA 449 F1) by loading 3 mg of sample in an Al 2 . The kinetic parameters of char samples were derived by the integral method presented by Coats and Redfern [34].…”

Section: Thermogravimetric Analysismentioning

confidence: 99%

“…The potassium retained in the ash was proposed to appear as hydroxide [2] and to a minor extent as chloride due to the low concentration of chlorine [41]. With the exception of Ca 3 (PO 4 ) 2 and CaSO 4 identified here, all other compounds identified in this study have been previously detected in ash samples by Wu et al [2]. The peaks at about 23 , 34.4 and 42.5 in the wheat straw char indicated a decrease in cellulose crystallinity and formation of a turbostratic structure [42e44].…”

Section: X-ray Diffractionmentioning

confidence: 99%

“…This introduces a range of major technical challenges, related to the operation of the power plants. Irregular fibrous biomass particles increase the required energy input into the milling compared to coal, affecting the biomass burnout and creating additional challenges with the flame stability [1,2].…”

Section: Introductionmentioning

confidence: 99%

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Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity

Trubetskaya

Jensen

et al. 2016

Biomass and Bioenergy

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Si solid-state NMR Entrained flow reactor Oxygen reactivity Si bearing compounds a b s t r a c t Fast pyrolysis of wheat straw and rice husk was carried out in an entrained flow reactor at hightemperatures (1000e1500) C. The collected char was analyzed using X-ray diffractometry, N 2 -adsorption, scanning electron microscopy, particle size analysis with CAMSIZER XT, 29 Si and 13 C solid-state nuclear magnetic resonance spectroscopy and thermogravimetric analysis to investigate the effect of inorganic matter on the char morphology and oxygen reactivity. The silicon compounds were dispersed throughout the turbostratic structure of rice husk char in an amorphous phase with a low melting temperature (z730 C), which led to the formation of a glassy char shell, resulting in a preserved particle size and shape of chars. The high alkali content in the wheat straw resulted in higher char reactivity, whereas the lower silicon content caused variations in the char shape from cylindrical to near-spherical char particles. The reactivities of pinewood and rice husk chars were similar with respect to oxidation, indicating less influence of silicon oxides on the char reactivity.

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Section: X-ray Diffractionmentioning

confidence: 46%

Section: Thermogravimetric Analysismentioning

confidence: 99%

Section: X-ray Diffractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity

Trubetskaya

Jensen

et al. 2016

Biomass and Bioenergy

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“…While Si is widely present in biomass ash deposits, the presence of K 2 CO 3 has been identified in a few studies in literature [19,20]. SiO 2 does not seem to significantly affect the adhesion strength under the conditions examined.…”

Section: Effect Of Compositionmentioning

confidence: 82%

Deposit Shedding in Biomass-Fired Boilers: Shear Adhesion Strength Measurements

Laxminarayan

Jensen

et al. 2017

Energy Fuels

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Ash deposition on boiler surfaces is a major problem encountered during biomass combustion. Ash deposition adversely influences the boiler efficiency, may corrode heat transfer surfaces, and may even completely block flue gas channels in severe cases, causing expensive unscheduled boiler shutdowns. Therefore, timely removal of ash deposits is essential for optimal boiler operation. In order to improve the understanding of deposit shedding in boilers, this study investigates the shear adhesion strength of biomass ash deposits on superheater tubes. Artificial biomass ash deposits were prepared on superheater tubes and sintered in an oven at temperatures up to 1000 °C. Subsequently, the deposits were sheared off by an electrically controlled arm, and the corresponding adhesion strength was measured. The results reveal the effect of temperature, deposit composition, sintering duration, and steel type on the adhesion strength.

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Numerical investigation on deposition rate of mechanically mixed ash particles in an entrained flow reactor

Wang

Tan

et al. 2021

Asia-Pacific J Chem Eng

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Homogeneous nucleation and heterogeneous condensation of salt vapors near the wall of superheater or reheater tubes greatly improve the sticky propensity of deposited surfaces or impacting particles and then lead to a fast‐growing rate of initial layer. Based on the deposition experiment of mechanically mixed KCl + SiO2 particles in an entrained flow reactor, a numerical model with considering the salt particle vaporization, salt vapor condensation, and its effect on SiO2 deposition is proposed for simulating impaction and adhesion behavior of molten and solid particles. The results show that deposits are mainly from the impaction of solid and molten particles and the condensation of salt vapors. The condensation rate of salt vapors in the stagnation zone at the windward side of metal probe is maximal. In comparison with the overall deposition rate, although the amount of salt vapors condensed on the probe surface can be negligible, it significantly affects the deposition rate of SiO2 particles. The coupled CFD model over a link between particle sticking and salt vapor condensation could well simulate the deposition behavior of mechanically mixed ash particles under rich‐salt‐vapor atmosphere.

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Impact of coal fly ash addition on ash transformation and deposition in a full-scale wood suspension-firing boiler

Cited by 65 publications

References 67 publications

Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity

Comparison of high temperature chars of wheat straw and rice husk with respect to chemistry, morphology and reactivity

Deposit Shedding in Biomass-Fired Boilers: Shear Adhesion Strength Measurements

Numerical investigation on deposition rate of mechanically mixed ash particles in an entrained flow reactor

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