Reduction mechanisms of ash deposition in coal and/or biomass combustion boilers

Naganuma, Hiroshi; Ikeda, Nobuya; Ito, Tadashi; Matsuura, Motoharu; Nunome, Yoko; Ueki, Yasuaki; Yoshiie, Ryo; Naruse, Ichiro

doi:10.1016/j.fuel.2012.11.017

Cited by 35 publications

(14 citation statements)

References 20 publications

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“…Slagging and ash deposition are affected by the adhesion force between heating surfaces and ash components, especially Nabased compounds [22]. The ash particles on the probes certainly contain viscous materials that melt easily at 900°C, such as silicates and sulfates [9,23].…”

Section: Deposition Tendency At Different Wall Temperaturesmentioning

confidence: 99%

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Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification

Song

et al. 2016

Applied Thermal Engineering

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Section: Deposition Tendency At Different Wall Temperaturesmentioning

confidence: 99%

“…These fine particles adhered onto metal surfaces to form the initial ash deposition layer [33]. Especially among minerals, the presence of alkali sulfates greatly enhanced the adhesion force between ash and metal surfaces [22].…”

Section: P5mentioning

confidence: 99%

Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification

Song

et al. 2016

Applied Thermal Engineering

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“…This is a key point to consider because this ash deposition makes an extra layer on surfaces where thermal heat is exchanged between flue gas and water. This extra layer low thermal heat transference (Naganuma et al, 2013;Vassilev et al, 2010). One should have in mind that ash heat conductivity transference is nearly as high as boiler's inner surfaces which often are made in metal.…”

Section: Introductionmentioning

confidence: 99%

Optimal processing of greenhouse crop residues to use as energy and CO2 sources

Reinoso-Moreno

Hernández

Fernández³

et al. 2019

Industrial Crops and Products

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This work presents the development of suitable strategies focusing on greenhouse crop residues as energy and CO 2 sources for improved food production in greenhouses. The utilization of greenhouse crop residues in combustion processes for heating and carbonic enrichment in greenhouses has previously been developed and evaluated. Nevertheless, greenhouse crop residues present several problems that make it difficult to use them for these purposes. Among the characteristics that can impede their use are excessive moisture and ash contents as well as their low density. In this work, the relevant solid fuel properties for this type of biomass have been studied. In addition, three pre-treatment strategies are proposed and evaluated, which aim to enhance the fuel quality of this biomass. These strategies were: 1) first relates to the drying strategy employed for reducing greenhouse crop residue moisture. 2) the second one relates to a reduction in ash content by avoiding contact with greenhouse soil and 3) mixing with other biomass kinds with better quality as solid fuels. The assays performed showed that these strategies were successful, resulting in biomass with a high heating value, up to 26.9 MJ/kg, and a lower ash content than untreated residues, with values as low as 13.0% dry weight. This value is closer to that for the standard biomass most commonly employed in direct combustion applications. The biomass produced has been verified as suitable for conventional boilers with thermal efficiencies up to 70%. The methods developed allow to reuse greenhouse crop residues as greenhouse fuel, providing both heat and CO 2 ; thus enhancing production and sustainability.

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“…Some scholars studied the application of coatings in reducing the adhesion force of molten ash. Naganuma et al [6,7] performed a field test in an actual multi-fuel boiler by arc spraying. They found that nickel alloy with thermal spraying coating effectively reduces the adhesion of ash particles.…”

Section: Introductionmentioning

confidence: 99%

Effect of filler on adhesion characteristics of precursor ceramic coating against high-temperature molten ash

Zhang

et al. 2022

J. Phys.: Conf. Ser.

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In view of the widespread high-temperature molten ash adhesion problem of heat exchanger surface in the chemical, power, metallurgy and other industries, precursor ceramic coating is proposed to reduce ash adhesion strength. Three ceramic coatings were obtained by adding hexagonal boron nitride (h-BN), zirconia (ZrO2) and aluminium oxide (Al2O3) inert fillers on TP347 steel sheets through the Czochralski method and high-temperature sintering. Results of the static contact angle test show that at 860°C, the contact angles of the molten ash on the coating surfaces of h-BN, ZrO2 and Al2O3 are 58°, 54° and 53°, respectively, which are greater than that (39°) of the steel sheet sample. The spreading radiuses of the three coatings are significantly less than that of the bare sample, indicating a strong anti-adhesion performance, in which the h-BN coating is the best. Spreading dynamic analysis of the bare and h-BN coating samples reveals that the spreading dynamics of both sample surfaces is driven by a combination of reaction, dissolution and diffusion. The inert filler in the coating makes the reaction and dissolution of molten ash on the coating surface weaker than those of the steel sheet. The micromorphology of the melt ash-sample sheet cross-section shows that the melt ash binds closely to the steel sheet sample oxide layer, whereas the boundary with the coating is clear and obvious. This result indicates that the coating can effectively weaken the wetting and permeability of the molten ash. The research results provide new ideas for precursor ceramic coating to solve the high-temperature melting ash adhesion problem of the heat exchanger surface.

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Reduction mechanisms of ash deposition in coal and/or biomass combustion boilers

Cited by 35 publications

References 20 publications

Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification

Effects of wall temperature on slagging and ash deposition of Zhundong coal during circulating fluidized bed gasification

Optimal processing of greenhouse crop residues to use as energy and CO2 sources

Effect of filler on adhesion characteristics of precursor ceramic coating against high-temperature molten ash

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