Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles

He, Honghao; Lu, Xiaofeng; Wei, Shuang; Wang, Quanhai; Kang, Yinhu; Yan, Liyun; Ji, Xuanyu; Luo, Guangyu; Liu, Hai

doi:10.1016/j.partic.2014.02.004

Cited by 23 publications

(15 citation statements)

References 38 publications

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“…At the operating temperature of 300°C, two major frequencies were observed in the PSD distribution of the pressure signals measured at P3. The first major peak (0.5–1 Hz) was related to the formation of bubbles, whereas the second largest peak was associated with small bubbles surrounding a single bubble; this indicated the transition from multiple bubble fluidization to single bubble fluidization . When the operating temperature was increased to 550°C, only one major peak was observed in the PSD distribution pattern but with a major frequency around 1.5 Hz.…”

Section: Resultsmentioning

confidence: 98%

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Xiao

Chun

Chen

et al. 2019

Asia-Pacific J Chem Eng

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This study describes experimental explorations on the effects of gas extraction on hydrodynamics in a pilot-scalegas fluidized bed membrane reactor (FBMR) at high temperatures. Differential pressure signals were measured at different vertical intervals in bed and were then characterized by multiscale resolution and power spectra analysis. The experimental results showed that the relative amplitude of σ r (σ/x av ) of pressure signal tended todecrease with the increase of gas extraction fraction.At room temperature, 20% gas extraction caused defluidization at an inlet velocity of 2U mf . However, athigh temperatures the gas extraction simultaneously decreased the magnitude of the low-frequency components and the numbers of the medium-to small-sized structures, mainly due to the decreased number of small-sized structures and the integration of bubbles. This effect of gas extraction increased with increase of gas extraction fraction and slightly decreased at higher inlet gas velocities. At elevated temperatures, the D6 sub-signals (0.781~1.562Hz) possessed the highest wavelet energy distribution percentage of the pressure signals, which meant that the medium-to small-sized bubbles dominated the gas-solid flow dynamics. Gas extraction was observed to enhance the dominance of the D6 scale components..

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Section: Resultsmentioning

confidence: 98%

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Xiao

Chun

Chen

et al. 2019

Asia-Pacific J Chem Eng

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“…Mostoufi et al 45 mentioned that all pressure signals were normalized (by subtracting the mean value from the signal and then dividing by the standard deviation) before applying STFT. He et al 19 , where method(ts) generates a characteristic number estimated from the ts. When S n is equal to zero, the method is not sensitive to data normalization.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

Sensitivity Study on Quantitative Methods by Analysis of Pressure Fluctuations in a Fluidized Bed

Wang

Chen

Wang

2018

Ind. Eng. Chem. Res.

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The sensitivity and reliability of 23 data processing methods are studied by analyzing pressure fluctuation time series in a fluidized bed. First, the concept of minimal stationary segment length is proposed to study signal stationarity. Second, three indexes estimating the sensitivity of the methods are proposed and their algorithms are designed. The sensitivity problems of some methods are studied. The results show that the root causes of the SKEW (skewness) method sensitive to segment length include outliers and a small value as the denominator, and the STD (standard deviation) method is sensitive to data normalization because it depends on the range of time series. Finally, a common framework is proposed based on the three sensitivity indexes and harnessed to evaluate the 23 methods. The two most reliable methods are picked and proved appropriate for identifying the flow regimes. Additionally, the result also indicates that the time-domain methods have better reliability than frequency-domain and state-space methods.

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“…Sand, glass beads, or alumina are typically used as inert bed materials due to their excellent fluidization and heat transfer properties, high sphericity, and resistance to breaking. It was observed that biomass particles significantly affect the fluidization hydrodynamics, such as minimum fluidization velocity, regime transitions, pressure fluctuation, and expanded bed fluctuation, mixing, and segregation . Compared with fluidization of inert bed materials alone, the fluidization behaviors of biomass and inert material mixtures are more complex and unique because the solid phase consists of two components with different physical properties, for example, density, size, and shape, which make the interaction between irregular shape biomass particles and the inert particles more complicated.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive experimental investigation on biomass‐glass beads binary fluidization: A data set for CFD model validation

Gao

et al. 2019

AIChE Journal

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Fluidization behavior of biomass and glass beads binary mixtures in a bubbling fluidized bed was experimentally investigated. Mixtures containing different mass fraction of Loblolly Pine white wood and glass beads were fluidized at different fluidization velocities. The particle properties were characterized in a QICPIC that uses a dynamic image processing method to measure both particle size and sphericity. The minimum fluidization velocity was determined using the pressure drop method. An image processing method was developed to capture the dynamic expanded bed height at a very high frequency. The effect of biomass mass fraction and inlet gas velocity on mixing and segregation behavior was studied and analyzed through pressure drop measurements. Pressure drop fluctuations and expanded bed height fluctuations via fast Fourier transform were analyzed and compared. The complete and accurate experimental data reported in this study could provide a benchmark data set for various computational fluid dynamics models validation, calibration, and identification.

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Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles

Cited by 23 publications

References 38 publications

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

Sensitivity Study on Quantitative Methods by Analysis of Pressure Fluctuations in a Fluidized Bed

Comprehensive experimental investigation on biomass‐glass beads binary fluidization: A data set for CFD model validation

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