Measurement and prediction of fly ash resistivity over a wide range of temperature

Zheng, Chenghang; Liu, Xintao; Yan, Ping; Zhang, Yongxin; Wang, Yi; Qiu, Kunzan; Gao, Xiang

doi:10.1016/j.fuel.2017.12.047

Cited by 22 publications

(6 citation statements)

References 18 publications

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“…As shown in the inserts in Figure (b), the resistivity of the total fly ash into the ESPs was reduced by 1 order of magnitude. The effects of added kaolin on the resistivity of the fly ash were consistent well with the reduced Ca and increased Si/Al contents (Figures and S4) in it, which finally enhanced the charging and capture of the PM in the ESPs. − The above phenomena have never been observed or realized in previous studies, which gave an important enlightenment that the impacts on the equipment after boiler should also be evaluated when screening suitable in-furnace de-PM additives.…”

Section: Resultssupporting

confidence: 69%

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM_2.5 in a 1000 MW Coal-Fired Power Station

Liu

Wang

et al. 2018

Environ. Sci. Technol.

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The impacts of in-furnace kaolin addition on the formation and emission characteristics of PM from a 1000 MW coal-fired utility boiler equipped with electrostatic precipitators (ESPs) are investigated for the first time ever in this contribution. Detailed characterization of the chemical composition, micromorphology, melting characteristics of the fine PM, total fly ash, and/or bottom ash samples were carried out using the X-ray fluorescence probe, the field emission scanning electron microscope coupled with an energy dispersive X-ray detector, the ash fusion analyzer, and the dust specific resistivity analyzer. The results showed that the formation of fine PM was reduced when kaolin was added, and the mass concentrations of the particulate matter with the aerodynamic diameters of ≤0.3 and 2.5 μm (PM and PM) were reduced by 55.97% and 5.48%, respectively. As expected, kaolin reacted with the volatile mineral vapors (e.g., Ca, Na) and inhibited their partitioning into ultrafine PM. It was interesting to find that the added kaolin modified the ash melting behavior, and promoted the capture of the ultrafine PM onto the coarse particles. What is more, the added kaolin reduced the specific resistivity of the fly ash and improved their capture efficiency in the ESPs. Finally, the above combined effects brought about the emission reductions of 41.27% and 36.72% for PM and PM after the ESPs. These results provided a direct confirmation on the feasibility of in-furnace kaolin addition on the PM reduction in the realistic combustion conditions.

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Section: Resultssupporting

confidence: 69%

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM_2.5 in a 1000 MW Coal-Fired Power Station

Liu

Wang

et al. 2018

Environ. Sci. Technol.

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“…where U layer is the voltage of the dust layer [V], ρ is the resistivity of the dust layer [Ω•cm], and division by 100 is due to unit conversion. The resistivity of the dust layer considering chemical composition and temperature can be directly measured by experiment or calculated as follows (Zheng et al, 2018b):…”

Section: Dust Layermentioning

confidence: 99%

“…Other important parameters are the properties of dust particles, including particle size, chemical composition, and resistivity, which have been studied widely (Bhanarkar et al, 2008;Jedrusik and Swierczok, 2009;Sui et al, 2016). Some studies show that the particle size distribution of typical fly ash samples from different industries vary (Zheng et al, 2018b), and median diameter could be increased by chemical and electric agglomeration (Chang et al, 2017;Hu et al, 2018). Besides, the main chemical components of the particles are Si, Al, Fe, Ca, Mg, K, and Na.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Investigation of the Effect of Dust Layer on Particle Migration in an Electrostatic Precipitator

Gao

Wang

Zhang

et al. 2020

Aerosol Air Qual. Res.

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Electrostatic precipitation processes have been widely applied to remove particulate matter from flue gases in coal-fired power stations. A high negative voltage is usually applied to a discharge electrode so that the gases are ionized in such processes. When the suspended particles in flue gases enter the ionized space, they are electrically charged and deposited on collection plates to form the layer of particle packing. However, the dust layer generally exists during the precipitation of charged particles on the collection plate. The negative effect of precipitated dust layer on the collection plate causes the collection efficiency of electrostatic precipitator (ESP) to deteriorate seriously due to some critical factors, such as dust resistivity and thickness of accumulated dust. In this study, a simulation method by computational fluid dynamics method was applied to investigate the particle collection performance of the ESP system with and without a dust layer. Also, the detailed electric parameters and particle capture performance in the 2D wire-plate electrode configuration were simulated. The results show that the voltage-current characteristics and detailed distribution of electric field and ion charge density are completely different under various dust resistivity conditions. The effect of the dust layer is significant, which causes collection efficiency to decrease sharply with the increasing thickness (1-5 mm) of the dust layer. Furthermore, results indicate that when particles with higher resistivity enter the ESP, their migration velocity decreases sharply. In the case of 80 kV, when the dust resistivity is 10 12 Ω•cm, the decline rate of particle migration velocity reaches 57.7%. Meanwhile, useful suggestions were provided to reduce the effects of dust layers by regulating particle properties and designing dust removal systems.

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“…Apart from predicting compressive strength on Portland cement mix designs, others have modeled the effect that SCMs, particularly fly ash, have on hardened cementitious properties, such as electrical resistivity, compressive strength, chloride resistance, expansion caused by alkali-silica reaction (ASR), and ion diffusivity [8][9][10][11][12][13][14][15]. ML has also been used to attempt to screen the reactivity of fly ashes based on their network topology [16].…”

Section: Introductionmentioning

confidence: 99%

Advancing cement-based materials design through data science approaches

Rios¹,

Childs²,

Smith³

et al. 2021

RILEM Tech Lett

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The massive scale of concrete construction constrains the raw materials’ feedstocks that can be considered – requiring both universal abundance but also economical and energy-efficient processing. While significant improvements– from more efficient cement and concrete production to increased service life – have been realized over the past decades through traditional research paradigms, non-incremental innovations are necessary now to meet increasingly urgent needs, at a time when innovations in materials create even greater complexity. Data science is revolutionizing the rate of discovery and accelerating the rate of innovation for material systems. This review addresses machine learning and other data analytical techniques which utilize various forms of variable representation for cementitious systems. These techniques include those guided by physicochemical and cheminformatics approaches to chemical admixture design, use of materials informatics to develop process-structure-property linkages for quantifying increased service life, and change-point detection for assessing pozzolanicity in candidate supplementary cementitious materials (SCMs). These latent variables, coupled with approaches to dimensionality reduction driven both algorithmically as well as through domain knowledge, provide robust feature representation for cement-based materials and allow for more accurate models and greater generalization capability, resulting in a powerful design tool for infrastructure materials.

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Measurement and prediction of fly ash resistivity over a wide range of temperature

Cited by 22 publications

References 18 publications

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM_2.5 in a 1000 MW Coal-Fired Power Station

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM_2.5 in a 1000 MW Coal-Fired Power Station

A Numerical Investigation of the Effect of Dust Layer on Particle Migration in an Electrostatic Precipitator

Advancing cement-based materials design through data science approaches

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Measurement and prediction of fly ash resistivity over a wide range of temperature

Cited by 22 publications

References 18 publications

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM2.5 in a 1000 MW Coal-Fired Power Station

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM2.5 in a 1000 MW Coal-Fired Power Station

A Numerical Investigation of the Effect of Dust Layer on Particle Migration in an Electrostatic Precipitator

Advancing cement-based materials design through data science approaches

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Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM_2.5 in a 1000 MW Coal-Fired Power Station

Influences of In-Furnace Kaolin Addition on the Formation and Emission Characteristics of PM_2.5 in a 1000 MW Coal-Fired Power Station