Statistical and frequency analysis of pressure fluctuation in an annular spouted bed of coarse particles

Gao, Hanyang; Gong, Xiwu; Hu, Guoxin

doi:10.1016/j.powtec.2017.05.007

Cited by 24 publications

(9 citation statements)

References 41 publications

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“…The standard deviation ( σ ) began to increase with increasing inlet superficial gas velocities U in the bubbling fluidization regime and then decreased after reaching the maximum. This change (marked in Figure ) is commonly interpreted as the dominance of the turbulent fluidization . Solomon et al, Cai et al, and Ellis et al utilized several different particles as fluidization particles to found a similar change that the emergence of the maximum in the standard deviation indicated the transition to turbulent fluidization in the flow patterns, and discovered bigger particles have a higher transition velocity simultaneously.…”

Section: Resultsmentioning

confidence: 86%

“…The major peak intensity of the PSD generally increased at higher measurement intervals, regardless of whether gas extraction occurred or not. This was related to the coalescence and growth of the bubbles as they rose to the bed surface . However, the increment of the gas extraction operation was significantly lower than under normal operating conditions.…”

Section: Resultsmentioning

confidence: 94%

“…H 2 perm‐selective membranes also have been utilized for the water–gas shift reaction and steam reforming of higher hydrocarbons in a fluidized bed reactor to promote the hydrogen yield. Hydrogen perm‐selective membranes can also be used to enhance the dehydrogenation reaction . By integrating hydrogen separation with reforming reactions, higher reactant conversions were achieved at mild operating temperatures and ultrapure hydrogen flow with purity >99.995% was obtained in the permeate lines .…”

Section: Introductionmentioning

confidence: 99%

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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: 86%

Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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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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“…Another drying technique that can be used for coarse particles is spouted bed technology. This technique provides a high solid circulation rate and increases contact between the drying agent and solid particles (Gao et al 2017;Zhang et al 2017). Other drying processes that can be used to obtain herbal products are centrifugal atomization, vacuum belt dryers, roller dryers, drying ovens, freeze dryers, and microwave dryers.…”

Section: Technological Methods To Obtain Productsmentioning

confidence: 99%

Food Composition Data: Edible Plants in Cerrado

et al. 2021

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181negative correlation between the in vitro potential of many molecules and their ADME/T (absorption, distribution, metabolism, excretion/toxicity) profile is generally noted (Gleeson et al. 2011). Synthetic compounds present a significantly lower number of chiral centers and are both smaller and present greater flexibility, which results in weaker, less specific activity (Feher and Schmidt 2003). In contrast, plantderived natural products present a diversity of bioactive compounds with differing chemical scaffolds (Atanasov et al. 2015). Plant-derived products possess properties, such as binding affinities for specific proteins, that are evolutionary optimized (Appendino et al. 2010;Hunter 2008). Such characteristics make plant-derived products more advantageous for conducting ADME/T tests (Atanasov et al. 2015). Another advantage in drug discovery using medicinal plants is the known good correlation between ethnopharmacological information (well documented) and the medical use of the plant. Around 80% of identified compounds present some ethnomedicinal use, whether identical or related to current usage of the active plant elements (Fabricant and Farnsworth 2001). Further, technological advances in systems biology, bioinformatics, plant specialized metabolism, and synthetic biology present opportunities through which the medicinal properties of plants are discovered, utilized, and expanded toward developing new herb-inspired medicines (Li and Weng 2017). Accordingly, plant-derived natural products still represent a valuable source for drug discovery, this, motivated by global public health challenges, such as COVID-19, HIV/AIDS, malaria, hypertension, diabetes, and cancer (Thomford et al. 2018). About a quarter of all Food and Drug Administration (FDA)-and/or European Medical Agency (EMA)-approved drugs are plant-derived (Patridge et al. 2016;Thomford et al. 2018).In this context, Brazil possesses various biomes with a great portion of the world's biodiversity and approximately 20% of the plants and microorganisms on the planet (Calixto 2000). Among these biomes, the Cerrado is a neotropical savanna with rich flora (Klink and Machado 2005). Over 13,127 highly endemic plant species have been recorded within this biome (Myers et al. 2000;Overbeck et al. 2015;Silva and Bates 2002;Silveira et al. 2016). Yet, in regard to environmental conservation, only 41% of the original Cerrado still remains as native vegetation (Soares-Filho et al. 2014). This reduction is due to anthropogenic activities, such as monoculture, pasture expansions, mineral extraction, and the growth of urban areas (Faleiro et al. 2013). Considering only agricultural activity between 2002 and 2009, an estimated loss of 92,712 km 2 of natural Cerrado area has occurred (Overbeck et al. 2015). Preservation policies in Brazil need improvement, yet only 7% of the Cerrado is under legal protection (Soares-Filho et al. 2014).Both the bio-prospecting potential of the Cerrado for medicinal species and knowledge concerning traditional medicines are disappear...

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“…Because gas–solid flow may exhibit many characteristics in different flow regimes, such as stochastic, broadband spectrum, and so on, it is natural to use a variety of methods to analyze , and compare to find which methods are more appropriate. Some researchers used statistical and frequency analysis methods − to characterize the flow regimes and pointed out that some methods might be more appropriate. Li et al found three flow regimes and two transition points are successfully identified by the methods of statistics, Hurst, Hilbert-Huang transform and Shannon entropy; they also found that the Hilbert-Huang transform and Shannon entropy analysis methods offered very high resolution in identifying the different flow regimes.…”

Section: Introductionmentioning

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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Statistical and frequency analysis of pressure fluctuation in an annular spouted bed of coarse particles

Cited by 24 publications

References 41 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

Food Composition Data: Edible Plants in Cerrado

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

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