Formation of carbonaceous cenospheres during fluidized-bed combustion of bituminous coals

Gay, Anne‐Sophie; Littlejohn, R. F.; Duin, P.J. van

doi:10.1016/0016-2361(83)90068-6

Cited by 6 publications

(6 citation statements)

References 2 publications

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“…However, the globules show no blowholes on the surface as seen on the type A cenosphere. This structure is also observed by Moszkowicz et al during fast pyrolysis of heavy fuel oil droplets, by Gay et al during burning of bituminous coal in a fluidized bed, and by Wornat et al from single-droplet combustion of pine oil.…”

Section: Results and Discussionsupporting

confidence: 68%

“…However, the globules show no blowholes on the surface as seen on the type A cenosphere. This structure is also observed by Moszkowicz et al 31 during fast pyrolysis of heavy fuel oil droplets, by Gay et al 28 during burning of bituminous coal in a fluidized bed, and by Wornat et al 12 from single-droplet combustion of pine oil. The last type (type C) has perfectly spherical and smooth morphology, whose diameter is much smaller than other two types of cenosphere, ranging from 10 to 100 μm.…”

Section: Resultssupporting

confidence: 58%

“…It is also hollow but does not present any porous structure on the surface. One interesting phenomenon should be mentioned here that most of the published studies ,,− on cenosphere formation only observed one or two types of morphology, including larger hollow globules and medium porous cenospheres. But in our current work, we observed three types of cenosphere morphology under combustion conditions without the interference of droplet–droplet interactions, including not only the above two types but also this very fine type with a perfectly spherical and smooth structure.…”

Section: Results and Discussionmentioning

confidence: 96%

“…Type A is a common morphology that has been widely observed, ,− and it has a carbonaceous and porous shell. It is smaller than the initial HFO droplet.…”

Section: Results and Discussionmentioning

confidence: 99%

“…It is also hollow but does not present any porous structure on the surface. One interesting phenomenon should be mentioned here that most of the published studies 12,22,[26][27][28][29][30][31] on cenosphere formation only observed one or two types of morphology including larger hollow globules and medium porous cenospheres.…”

Section: Initial Droplet Size Calculationmentioning

confidence: 97%

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Cenosphere Formation during Single-Droplet Combustion of Heavy Fuel Oil

et al. 2019

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The current study aims to investigate cenosphere formation during single droplet combustion of heavy fuel oil (HFO). A droplet generator was developed to produce freely falling monodisperse droplets uniformly. With the aid of high-speed imaging, droplet diameter was verified to be well controlled within the range of 390~698 μm, and droplets spacing distance was sufficient to avoid the droplet-droplet interactions. Impacts of operation conditions (initial HFO droplet size, temperature, and air co-flow rate) and asphaltene content on cenosphere formation in a drop tube furnace were then investigated. Three types of cenosphere morphology were observed by a field-emission scanning electron microscopy (SEM), namely larger hollow globules, medium porous cenospheres, and smaller cenospheres with a perfectly spherical and smooth structure. The SEM image results show the mean diameter of collected cenospheres increased as initial droplet size and asphaltene content increased, while it decreased as temperature and air co-flow rate increased. The energy dispersive X-ray spectra (EDX) results show these parameters also significantly influenced the evolution of cenosphere surface elemental composition. All parameters show linear effects on the surface content of C, O and S, excluding air co-flow rate. The increase of air co-flow temperature enhanced the droplet combustion, conversely, the larger the initial droplet size and asphaltene content inhibited droplet combustion. The non-linear effect of air co-flow rate indicates that it has an optimum rate for falling droplet combustion, as 90 slpm based on the current experimental setup. Eventually, our study proposed the pathway of cenosphere formation during the HFO droplet combustion.

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Section: Results and Discussionsupporting

confidence: 68%

Section: Resultssupporting

confidence: 58%

Section: Results and Discussionmentioning

confidence: 96%

“…Type A is a common morphology that has been widely observed, ,− and it has a carbonaceous and porous shell. It is smaller than the initial HFO droplet.…”

Section: Results and Discussionmentioning

confidence: 99%