Enhancing fluidization stability and improving separation performance of fine lignite with vibrated gas‐solid fluidized bed

He, Junguo; Zhao, Yuemin; Zhao, Jie; Z, Luo; Chen, Duan; He, Yaqun

doi:10.1002/cjce.22272

Cited by 15 publications

(8 citation statements)

References 32 publications

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“…Their number is identified either by hydrodynamic factors (gas flow velocity) and layer height [17] or by granulometric composition and physical properties of the particles in the initial product [18,19]. The positive effect of vibrational oscillations on the separation process of small particles from the fluidized bed is noted [20,21].…”

Section: Literature Reviewmentioning

confidence: 99%

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

et al. 2021

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The article deals with the theoretical description and experimental study of the hydrodynamic and heat transfer properties regarding the operation of multistage gravitational devices of the fluidized bed with inclined perforated shelves. The peculiarities of the work and the implementation field of the multistage shelf units are described. A theoretical model to define the solubilizer’s velocity above the perforation holes, in the above-shelf space of the device and in the outloading gap, as well as the residence time of the dispersed phase at the stage (perforated shelf contact) of the device is presented. The results of experimental studies regarding the influence, made by the structural parameters of the perforated shelf contacts, on the distribution pattern of single-phase and gas-dispersed flows in the workspace of the device, on the intensity of interphase heat transfer are presented. The conditions to create active hydrodynamic operating modes of multistage gravitational shelf devices, which provide higher efficiency of heat-mass transfer processes, and with lower gas consumption and hydraulic resistance compared to typical fluidized bed devices, are proved. Peculiarities regarding the implementation of heat-mass transfer processes in multistage devices are described using heat treatment and drying processes as examples.

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Section: Literature Reviewmentioning

confidence: 99%

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

et al. 2021

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“…It is reported that promising results were achieved . The vibrated gas–solid fluidized bed was investigated and utilized for the drying and simultaneous separation of lignite . By introducing the vibrated energy, the fluidization stability as well as separation performance were improved significantly …”

Section: Introductionmentioning

confidence: 99%

“…6 The vibrated gas−solid fluidized bed was investigated and utilized for the drying and simultaneous separation of lignite. 21 By introducing the vibrated energy, the fluidization stability as well as separation performance were improved significantly. 21 The pulsed fluidized bed is a typical additional field fluidized bed, 22−24 which implements pulsating air flow to promote the diffusion and stratification of particles and improve the drying performance and separation efficiency.…”

Section: Introductionmentioning

confidence: 99%

Separation and Upgrading of Fine Lignite in Pulsed Fluidized Bed. 1. Experimental Study on Lignite Drying Characteristics and Kinetics

et al. 2017

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The pulsating flow was introduced into the gas–solid fluidized bed to enhance the diffusion and stratification of lignite particles and avoid channeling and short circuits with an attempt to achieve a better drying effect for fine lignite. A pulsed fluidized bed system was established, targeting the analysis of the drying and segregation characteristics of fine lignite. With the thermal input characterized by inlet temperature, thermal energy was transported into the fluidized bed and lignite particles, which accelerates the evaporation of surface water and interior water of lignite particles. Under the combination effect of thermal and pulsating energy, the drying efficiency was significantly improved. This paper mainly focuses on the influence of various operating factors on the drying characteristics of fine lignite in a pulsed fluidized bed and exploring the appropriate kinetic model for the drying process under different inlet temperatures in a pulsed fluidized bed. In the drying process, the drying rate was influenced dramatically in a positive way by the inlet temperature, gas velocity, and pulsating frequency, while the drying rate decreases with the increase of bed height. The increase of inlet temperature, gas velocity, and pulsation frequency reduced the moisture content and increased the drying rate. When the inlet temperature, air velocity, pulsating frequency, and bed height, which are 100 °C, 1.09 m/s, 3.06 Hz, and 120 mm, the water content of −6 + 3 mm lignite decreases dramatically from 31.66% to approximately under 8% after 12 min of drying. The water content of −3 + 1 mm lignite plummets from 29.99% to around 4% after 12 min of drying when inlet temperature, air velocity, pulsating frequency, and bed height are set as 100 °C, 0.61 m/s, 2.62 Hz, and 80 mm, respectively. An infinitesimal effect on the lignite drying can be detected when the gas velocity and the pulse frequency exceed a certain range. In the study of drying kinetics, fitting results under different temperatures combined with a thin layer drying model showed that the logarithmic model was the optimal model for interpreting the drying characteristic of fine lignite. After drying and separation, the calorific capacities of −6 + 3 mm lignite and −3 + 1 mm lignite increase by up to 60% and 67%, respectively. Hence, drying of fine lignite with a pulsed fluidized bed offers a feasible and economical method to enable further industrial application of lignite.

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“…It is reported that promising results were achieved . The vibrated gas–solid fluidized bed was investigated and utilized for the drying and simultaneously separation of lignite . By introducing the vibrated energy, the diffusion and stratification of lignite particles in pulsed fluidized bed are promoted, as well as the density-based hindered settling process.…”

Section: Introductionmentioning

confidence: 99%

“…By introducing the vibrated energy, the diffusion and stratification of lignite particles in pulsed fluidized bed are promoted, as well as the density-based hindered settling process. Hence, the separation performance was improved correspondingly …”

Section: Introductionmentioning

confidence: 99%

Separation and Upgrading of Fine Lignite in a Pulsed Fluidized Bed. 2. Experimental Study on Lignite Separation Characteristics and Improvement of Separation Efficiency

et al. 2017

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A pulsed fluidized bed system was established, targeting the analysis of the drying and separation characteristics of fine lignite. Experiments, involving factors of air velocity, pulsating frequency, and bed height were conducted under room temperature to analyze the influence of each factor on the separation characteristics of −6 + 3 mm lignite and −3 + 1 mm lignite in a pulsed fluidized bed, respectively. The combustible recovery and standard deviation of ash content were implemented to evaluate the separation efficiency. Results show three factors have a significant impact on the separation efficiency of fine lignite. Afterward, the thermal energy characterized by inlet temperature was imported into the pulsed fluidized bed system to study the influence of inlet temperature, air velocity, pulsating frequency, and bed height on the separation efficiency of fine lignite under thermal conditions. Results show that the ash content of the top layer product decreases significantly from 14.44% to 9.82% and from 15.52% to 7.31% when the pulsating frequency increases from 0 Hz to 3.93 Hz under room temperature and thermal conditions for −6 + 3 mm lignite, respectively. For −3 + 1 mm lignite, the ash content of the top layer product decreases from 17.22% to 10.25% and from 16.77% to 10.01% under room temperature and thermal conditions, respectively. Optimal operation parameters were determined. With the air velocity of 1.09 m/s, inlet temperature of 80 °C, pulsating frequency of 3.93 Hz, and bed height of 120 mm, the optimal separation efficiency was achieved for −6 + 3 mm lignite. For −3 + 1 mm lignite, the optimal is achieved when air velocity, inlet temperature, pulsating frequency, and bed height are 0.55 m/s, 100 °C, 3.49 Hz, and 80 mm. The separation efficiency of lignite with a pulsed fluidized bed was dramatically improved.

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Enhancing fluidization stability and improving separation performance of fine lignite with vibrated gas‐solid fluidized bed

Cited by 15 publications

References 32 publications

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

Separation and Upgrading of Fine Lignite in Pulsed Fluidized Bed. 1. Experimental Study on Lignite Drying Characteristics and Kinetics

Separation and Upgrading of Fine Lignite in a Pulsed Fluidized Bed. 2. Experimental Study on Lignite Separation Characteristics and Improvement of Separation Efficiency

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