An optical method of measuring the temperature in a fluidised bed combustor

Żukowski, Witold; Baron, Jerzy; Bulewicz, E.M.; Kowarska, Beata

doi:10.1016/j.combustflame.2009.03.004

Cited by 14 publications

(10 citation statements)

References 18 publications

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“…Local temperatures near the quartz walls of the reactor were also measured by an optical method, with much better resolution (in space and time) and with no sensors in the bed. Vertical and horizontal temperature profiles for the visually accessible regions of the bed were constructed and locally hotter sand was linked to explosions in bubbles [15]. On the basis of the observations, three combustion regimes were distinguished: A-the gases burning above the distributor, B-combustion inside the bed, with prominent acoustic effects and Creaction low down in the bed, with much less sound.…”

Section: Introductionmentioning

confidence: 99%

“…Optical recording is much simpler and suitable video cameras are readily available. Observations in the visible and near infra red, through the quartz walls of a laboratory reactor, can yield much useful information (subject to limitations due to radiation from the reactor walls) [10,15]. A fast video camera was used to record images of the phenomena observed when propane-air was burned in a bubbling fluidised bed of quartz sand.…”

Section: Introductionmentioning

confidence: 99%

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Propagation of Reaction Between Bubbles with a Gas Burning in a Fluidised Bed

Baron

Bulewicz

Zabagło

et al. 2011

Flow Turbulence Combust

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A bubbling fluidised bed reactor has been used for investigating how combustion propagates between bubbles of premixed fuel + air, rising from the distributor towards the surface. Earlier work has shown that when the temperature of the sand gradually rises, the gases first burn in flames above the bed, regime A, then combustion moves under its surface, to occur in bubbles travelling up the bed, under regime B. Above a certain temperature, characteristic of the gas mixture composition, combustion descends towards the bottom of the bed. Ignition then occurs in small bubbles near the distributor, under the stable regime C. The kinetic model, used to calculate the delay for thermal ignition inside gas bubbles rising through the bed, gives correct predictions for regimes A and C but not for B. Under regime B, bubbles of the mixture begin to ignite under the bed's surface while their residence time in the bed is remains shorter than the delay times for thermal ignition derived from the kinetic model. As the temperature rises, the ignition delay rapidly decreases, and regime C is reached, in accordance with the model. In this work attention was focused on regime B. A laboratory reactor of quartz glass was used, with a bed of quartz sand. Fast video recording was employed to capture ignition phenomena as the bed's temperature was raised or lowered. Records of freeboard concentrations of O 2 , CO and of total hydrocarbons, VOCs, were obtained, confirming the specific aerodynamic and chemical character of regime B. It has been shown that combustion spreads from the surface to bubbles near the bed's surface and then to other bubbles close by. Such transfer of the reaction stabilizes combustion inside the bed, at temperatures appreciably lower than that for the thermal ignition of the mixture, given by the kinetic model. This is consistent with earlier findings, which have shown that the combustion of gaseous mixtures in bubbling fluidised beds is controlled by gas phase processes, as in flames.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Propagation of Reaction Between Bubbles with a Gas Burning in a Fluidised Bed

Baron

Bulewicz

Zabagło

et al. 2011

Flow Turbulence Combust

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“…For an image of a volatiles flame, the red (R), green (G) and blue (B) color intensities are determined through an image processing program. The R and G color intensities and wavelength bands were chosen to calculate the temperature, since the camera is more sensitive to these two color intensities than to the blue one in the temperature range of interest, and a better signal-to-noise ratio can be achieved [18,19]. With the usual assumption of two-color pyrometry namely k 1 ¼ k 2 [17], Eq.…”

Section: Measurement Of Volatiles Flame Temperature By Two-color Pyromentioning

confidence: 99%

Devolatilization of a single fuel particle in a fluidized bed under oxy-combustion conditions. Part A: Experimental results

Leckner

Chen

et al. 2015

Combustion and Flame

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“…This property is only confined to the area of the emulsion phase. High-temperature reactors, such as furnaces of power boilers, are known to have the temperature gradient observed in the bubbles up to several hundred Kelvin (Basu, 2006;Żukowski et al, 2009). A significant gradient of temperature field also occurs in the area of rapid reaction such as ignition of fuel grain.…”

Section: Possibilities Of Temperature Distribution Analysis Using Ectmentioning

confidence: 99%

“…Unfortunately, this approach also disturbs the temperature field. There are also non-invasive measurements, based on an analysis of visible light emission recorded with a digital camera (Żukowski et al, 2009;Smart et al, 2010). The advantage of this method is high speed data recording, which allows the identification of even short-term changes in bed temperature.…”

Section: Possibilities Of Temperature Distribution Analysis Using Ectmentioning

confidence: 99%

Applications of Electrical Capacitance Tomography for Research on Phenomena Occurring in the Fluidised Bed Reactors

Porzuczek¹

2014

Chemical and Process Engineering

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The paper presents a review of current achievements in the Electrical Capacitance Tomography (ECT) in relation to its possible applications in the study of phenomena occurring in fluidised bed reactors. Reactors of that kind are being increasingly used in chemical engineering, energetics (fluidised bed boilers) or industrial dryers. However, not all phenomena in the fluidised bed have been thoroughly understood. This results in the need to explore and develop new research methods. Various aspects of ECT operation and data processing are described with their applicability in scientific research. The idea for investigation of temperature distribution in the fluidised bed, using multimodal tomography, is also introduced. Metrological requirements of process tomography such as sensitivity, resolution, and speed of data acquiring are noted.

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An optical method of measuring the temperature in a fluidised bed combustor

Cited by 14 publications

References 18 publications

Propagation of Reaction Between Bubbles with a Gas Burning in a Fluidised Bed

Propagation of Reaction Between Bubbles with a Gas Burning in a Fluidised Bed

Devolatilization of a single fuel particle in a fluidized bed under oxy-combustion conditions. Part A: Experimental results

Applications of Electrical Capacitance Tomography for Research on Phenomena Occurring in the Fluidised Bed Reactors

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