Mechanisms of Submicron and Residual Ash Particle Formation during Pulverised Coal Combustion: A Comprehensive Review

Yu, Dunxi; Xu, Minghou; Liu, X.; Huang, Jin; Li, G.

doi:10.1002/apj.5500130329

Cited by 14 publications

(18 citation statements)

References 40 publications

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“…In combustion systems, the very fine particles (especially the submicron aerosols) could readily escape conventional air pollution control devices (APCDs) and thus might pose serious risks to human health [4]. The health concerns have stimulated extensive research [7][8][9][10][11][12] on ash aerosol formation and properties in the last decades. Such information is of great significance.…”

Section: Introductionmentioning

confidence: 99%

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Coal combustion-generated aerosols: Formation and properties

Yao

et al. 2011

Proceedings of the Combustion Institute

301

199

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Section: Introductionmentioning

confidence: 99%

“…A number of related reviews are available in books [8,10,[13][14][15][16], academic journals [7,9,11,12,17], and conference proceedings [18,19]. However, most of them only discussed ash aerosols from pulverized coal combustion (PCC).…”

Section: Introductionmentioning

confidence: 99%

Coal combustion-generated aerosols: Formation and properties

Yao

et al. 2011

Proceedings of the Combustion Institute

301

199

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“…It could range from sizes greater than 30 microns to submicron. 28 Smaller, submicron slag droplets are formed predominantly due to vaporization and consequent condensation of metal oxides. 29 Larger slag droplets are formed as a result of complete coalescence.…”

Section: C 2015 American Institute Of Chemical Engineersmentioning

confidence: 99%

“…In this scenario, all the mineral content in the char particle coalesce to form a single slag droplet. 27,28 Given the extreme conditions within the gasifier, it is not necessary that the agglomerated mineral matter will only detach from the char particle when it approaches complete burnout. It is found that the separation of individual included mineral matter or partially coalesced mineral inclusion is found to result in sizes between 1 and 20 microns due to shedding or char fragmentation.…”

Section: C 2015 American Institute Of Chemical Engineersmentioning

confidence: 99%

Development of a hybrid shrinking‐core shrinking‐particle model for entrained‐flow gasifiers

et al. 2015

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in Wiley Online Library (wileyonlinelibrary.com) Slagging entrained-flow gasifiers operate above the melting temperature of the ash. As slag is highly nonwetting on the surface of char (carbon) particles, it is likely that it will agglomerate into one or several slag droplets and some of these droplets can detach from the char particles. If the slag exists in the form of droplets on the char surface rather than as a solid shell around the unreacted char particle, a shrinking particle model would be more physically realistic representation in comparison to the widely used shrinking core model (SCM). In the early section of the gasifier, the temperature remains below the ash melting temperature and, therefore, the SCM is more appropriate in this region. With this motivation, a novel hybrid shrinking-core shrinking-particle model has been developed. The model provides spatial profile of a number of important variables that are not available from the traditional SCM.

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“…Examples of such time-varied aerosols are the nucleation event of particles in the atmosphere (Weber et al, 1995(Weber et al, , 1996Mäkelä et al, 1997;Kulmala, 2003Kulmala, , 2004Kulmala, , 2013 and the aerosols produced by the combustion processes (Flagan, 1979;Leskinen et al, 1998;Yu et al, 2005;Xu et al, 2011). The performance of aerosol instruments under the challenge of time-varied aerosols needs to be understood in order to properly characterize the transient behavior of aerosols.…”

Section: Introductionmentioning

confidence: 99%

A Programmable Aerosol Diluter for Generating Time-Varied Sub-Micrometer Particles

Liu

Chen

2014

Aerosol Air Qual. Res.

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Real-world aerosols often vary over time. A time-varied aerosol generation system is thus needed to evaluate the performance of aerosol sensors for characterizing time-dependent aerosol size distribution. However, all laboratory aerosol generators are designed for the production of aerosols with stable concentrations and steady size distributions. A simple way to produce reliable time-dependent aerosols is to combine a stable aerosol generator with a programmable aerosol diluter. Aerosol diluters are also needed to measure aerosols in high concentrations using existing aerosol instruments. In this study we focused on the design and evaluation of a programmable aerosol diluter. The dilution flow rate of the aerosol diluter was controlled by a programmable mass flow controller with a flow rate of up to 200 L/min. Steady and dynamic dilution processes in the diluter were programmed using Visual Basic. Experiments were carried out to characterize the steady and dynamic dilution performance of the aerosol diluter for DMA-classified particles with sizes ranging from 10 nm to 1.0 µm. The steady dilution result shows that the diluter has a non-size dependent dilution performance, and there is a good linear relationship between the aerosol dilution ratio and dilution flow rate ratio (with a calibrated line slope of 1.03, close to the ideal line slope of 1.0). Our experiments further indicate that efficient aerosol mixing in the diluter can be achieved when operated at a flow Reynolds number above 450. The evaluation of four dynamic dilution modes also provides evidence of the excellent performance of the diluter, which has the capability of continuously producing welldefined and concentration-varied aerosols. A simple empirical model was also proposed to describe the steady and dynamic dilution performance of the diluter.

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Mechanisms of Submicron and Residual Ash Particle Formation during Pulverised Coal Combustion: A Comprehensive Review

Abstract: Coaljly ash has been a traditional concern of utilities since coal was used to generate electricity because it may bring about a number of technical and economic problems

Cited by 14 publications

References 40 publications

Coal combustion-generated aerosols: Formation and properties

Coal combustion-generated aerosols: Formation and properties

Development of a hybrid shrinking‐core shrinking‐particle model for entrained‐flow gasifiers

A Programmable Aerosol Diluter for Generating Time-Varied Sub-Micrometer Particles

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