Wavelet analysis to characterize cluster dynamics in a circulating fluidized bed

Guenther, Chris; Breault, Ronald W.

doi:10.1016/j.powtec.2006.12.016

Cited by 95 publications

(46 citation statements)

References 11 publications

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“…Lu et al 21 also determined the cluster frequency and size by the cross-correlation and wavelet analysis of local voidage signals in a downer CFB. Guenther and Breault 14 analyzed the fiber optic signals by using discrete wavelet analysis to characterize the dynamic behavior of clusters of cork particles at different axial and radial positions in a large scale CFB operated at three different flow regimes. They proposed two rules of wavelet analysis to determine the length and count of clusters based on the 50th percentile value of the reconstructed signal.…”

Section: Introductionmentioning

confidence: 99%

Multiresolution analysis on identification and dynamics of clusters in a circulating fluidized bed

Yang

Leu

2009

AIChE Journal

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). An appropriate level of approximation subsignal was systematically specified as a threshold for cluster identification, based on multiresolution analysis (MRA) of wavelet transformation. By the established threshold, the dynamic properties of clusters including the appearance time fraction of clusters F cl , average cluster duration time s cl , cluster frequency f cl , and local average solids holdup in clusters e sc , at different radial and axial positions were determined under the turbulent, transition and fast fluidization flow regimes. The results also describe the dynamic properties of clusters and flow patterns in the splash zone along with the dense bottom region of the circulating fluidized beds.

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Section: Introductionmentioning

confidence: 99%

Multiresolution analysis on identification and dynamics of clusters in a circulating fluidized bed

Yang

Leu

2009

AIChE Journal

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“…[19] acquired the image sequences of the formation, movement and decomposition of the glass beads clusters on a cold CFB. Guenther and Breault [20] concluded that the continuous formation and destruction of clusters strongly influences particle holdup, pressure drop, heat transfer at the wall and mixing.…”

Section: Introductionmentioning

confidence: 99%

Prediction of cluster diameter for a wide range of particles for gas–solid dispersed phase in a fast fluidized‐bed reactor

Das

Meikap

Saha

2008

Asia-Pacific J Chem Eng

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Fast fluidized-bed (FFB) reactors have been used in chemical process industries. Clustering behavior of the FFB has been studied with Geldart group B particles like coal and iron ore in a circulating fluidized bed (CFB) of inner diameter 0.1016 m and height 5.62 m. Clustering phenomena has been investigated by incorporating the effects of acceleration and friction into the homogeneous gas-solid cluster suspension model. The cluster diameter calculated from homogeneous cluster suspension model appears to tally with the measured data when the particle concentration in the suspension lies in the dilute phase. It has been found that the acceleration has some effect on the cluster diameter. However, the solid friction does not have any significant role. The result of the present study gives a clear understanding of clustering phenomena in FFB. 

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“…The heat and mass transfer behavior of fuel particles in clusters can still be analogous to that in the emulsion phase of dense bed. As the cluster tendency of particles is higher than that of coarse particles, and the increasing solid circulation rate leads to the larger size of clusters [64,65], the mass transfer between the gas and clusters is reduced when the bed material size is smaller. The reducing atmosphere in the upper furnace reduces the generation of NO x [66].…”

Section: Formation and Reduction Of No X In Cfb Combustionmentioning

confidence: 99%

Progress of circulating fluidized bed combustion technology in China: a review

Cai

Lyu

et al. 2017

Clean Energy

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Circulating fluidized bed (CFB) technology plays an important role in the utilization of low-grade coal in China. This article reviews CFB combustion technology development in China and summarizes recent achievements. Since 1990 Chinese engineers and researchers have been undertaking work to improve CFB boiler technology. A completely novel CFB boiler design theory was developed and used in the domestic manufacturing of CFB boilers with various capacities. China is the largest supplier and customer of CFB boilers in the world due to the widespread use of CFB boilers. In 2007, the lower energy consumption CFB technology was successfully developed by re-specifying the fluidization state, which reduced the power consumption of forced fans and solved the potential erosion problems on the water wall. Afterwards, in order to increase the electric power generation efficiency, the supercritical CFB (SCCFB) boiler was developed and the first 600 MW SCCFB boiler was demonstrated and put into commercial operation in 2013. The success of the technology is evident with over 80 SCCFB boilers on order with capacities of 350 MW to 660 MW. Chinese scientists and engineers are also developing technology to lower the emissions of CFB combustion to meet the requirements of China's strict emission regulations. This emission reduction is through high-efficiency desulfurization by limestone injection into the furnace and low NO x combustion, ultra-low emission of SO 2 and NO x in the furnace can be realized by improving the bed quality and increasing the solid circulation rate. There is currently further research and design development being undertaken to develop a 660 MW ultra-supercritical CFB (USCCFB) boiler. The new boiler is expected to be operational before 2020 resulting in higher efficiency and lower energy consumption and emissions.

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Wavelet analysis to characterize cluster dynamics in a circulating fluidized bed

Cited by 95 publications

References 11 publications

Multiresolution analysis on identification and dynamics of clusters in a circulating fluidized bed

Multiresolution analysis on identification and dynamics of clusters in a circulating fluidized bed

Prediction of cluster diameter for a wide range of particles for gas–solid dispersed phase in a fast fluidized‐bed reactor

Progress of circulating fluidized bed combustion technology in China: a review

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