Liquid-Solid Coupling Characteristics in the Fluidized Bed Evaporator for Tobacco Refined Liquid

2014 ◽  
Vol 686 ◽  
pp. 522-528
Author(s):  
Feng Lan Wang ◽  
Yuan Jun Yao ◽  
Fa Yun Gong ◽  
Fang Ping Ye ◽  
Wen Jie Qi
Keyword(s):  
Fluidized Bed ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Maximum Speed ◽  
Force Model ◽  
Liquid Density ◽  
Two Phase ◽  
Viscous Term ◽  
Inert Particles ◽  
Coupling Characteristics

Consider a two-phase liquid-solid coupling effect, using Euler - Euler two-fluid model is solved using standard viscous term with k-ε model and the velocity pressure coupling a simple algorithm to simulate liquid-solid two-phase flow characteristics of the fluid flow method bed, the applicability of the model to assess the drag. Different effects of a two-stage flow characteristics of fluidized bed flow characteristics, fluid and operating conditions affect the physical properties of the paper. We found from the simulation is the use of different drag coefficient models will greatly affect the results, which drag force model Syamlal - O'Brien is more suited to study the coupling characteristics of liquid flow in a fluidized bed of solid than Gidaspow. And velocity of the inert particles increase with the viscosity of the liquid increase. Further, the maximum speed of the inert particles in a fluidized bed by a central, which means the settling velocity in the fluidized bed of inert particles is the slowest; increasing liquid density and lead to increased speed of the inert particles; volume of the inert particles Score changes can also affect the speed of the particle velocity distribution, and there is no linear relationship.

scholarly journals Development of Hybrid Airlift-Jet Pump with Its Performance Analysis

2018 ◽  
Vol 8 (9) ◽  
pp. 1413 ◽  
Author(s):  
Dan Yao ◽  
Kwongi Lee ◽  
Minho Ha ◽  
Cheolung Cheong ◽  
Inhiug Lee
Keyword(s):  
Boundary Conditions ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Jet Pump ◽  
Two Phase

A new pump, called the hybrid airlift-jet pump, is developed by reinforcing the advantages and minimizing the demerits of airlift and jet pumps. First, a basic design of the hybrid airlift-jet pump is schematically presented. Subsequently, its performance characteristics are numerically investigated by varying the operating conditions of the airlift and jet parts in the hybrid pump. The compressible unsteady Reynolds-averaged Navier-Stokes equations, combined with the homogeneous mixture model for multiphase flow, are used as the governing equations for the two-phase flow in the hybrid pump. The pressure-based methods combined with the Pressure-Implicit with Splitting of Operators (PISO) algorithm are used as the computational fluid dynamics techniques. The validity of the present numerical methods is confirmed by comparing the predicted mass flow rate with the measured ones. In total, 18 simulation cases that are designed to represent the various operating conditions of the hybrid pump are investigated: eight of these cases belong to the operating conditions of only the jet part with different air and water inlet boundary conditions, and the remaining ten cases belong to the operating conditions of both the airlift and jet parts with different air and water inlet boundary conditions. The mass flow rate and the efficiency are compared for each case. For further investigation into the detailed flow characteristics, the pressure and velocity distributions of the mixture in a primary pipe are compared. Furthermore, a periodic fluctuation of the water flow in the mass flow rate is found and analyzed. Our results show that the performance of the jet or airlift pump can be enhanced by combining the operating principles of two pumps into the hybrid airlift-jet pump, newly proposed in the present study.

Aspects Concerning the Drying of Grained Biomaterials through Intensive Processes II. Malt Grain Drying in Fluidized Bed Formed by Inert Particles

2008 ◽  
Vol 59 (3) ◽  
pp. 283-291
Author(s):  
Monica Mares ◽  
Gabriela Isopencu ◽  
Cosmin Jinescu ◽  
Paul Vasilescu1 ◽  
Gheorghita Jinescu
Keyword(s):  
Experimental Study ◽  
Ambient Temperature ◽  
Fluidized Bed ◽  
Technological Process ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Drying Process ◽  
Atmospheric Air ◽  
Grain Drying ◽  
Inert Particles

Present paper have like objective the experimental study regarding the intensification of the drying process of malt using like drying agent the atmospheric air at ambient temperature and at 45oC, in flotation-fluidized bed. To reduce the operating drying period by using the fluidization agent at 45oC, it was studied the drying in mixt bed, formed by inert particles (sand, dp=150mm, smashed malt, ) and wet malt grains (in flotation state). Comparing the drying periods and the final moistures obtained at the malt drying in fixed bed (fixed mixt bed) with those obtained in fluidized mixt bed was establish that: the drying in fluidized conditions conduce at an uniform final moisture product; the economical operating conditions for a final moisture (4 - 6%) imposed by the technological process.

scholarly journals Research Progress on Numerical Simulation of Two-phase Flow in the Gas-solid Fluidized Bed

2021 ◽  
Vol 259 ◽  
pp. 04002
Author(s):  
Shujie Sun ◽  
Xiaosai Dong ◽  
Jie Wang ◽  
Haodong Zhang ◽  
Zhenya Duan
Keyword(s):  
Numerical Simulation ◽  
Fluidized Bed ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Research Progress ◽  
Phase Flow ◽  
Two Phase ◽  
Drag Model ◽  
Reaction Characteristics ◽  
Coupling Algorithm

It is difficult to accurately measure the parameters of solid particles in the experiment of the gas-solid fluidized bed. The numerical simulation plays an important role to accurately describe flow characteristics in the fluidized bed. Combined with the research work of the research group, this paper analyzes the application of numerical simulation of fluidized bed from the aspects of gas-solid coupling algorithm, drag model, flow characteristics, and reaction characteristics based on the previous studies. The specificity improvement of the gas-solid coupling algorithm and the regional application of the drag model is the trend of the recent development of numerical simulation. Previous studies mainly focus on the gas-solid two-phase flow field characteristics in the traditional fluidized bed, but few on the complex flow characteristics such as gas-solid reverse flow and the coupling with reaction characteristics. It is of great significance for designing a novel fluidized bed reactor to realize gas-solid continuous reaction to establish and improve the numerical simulation method of gas-solid non-catalytic reaction.

scholarly journals Modelling and Simulation of a Fluidized Bed Reactor for Minimum Ammonium Nitrate and Reduction of NOx Emissions

2018 ◽  
Vol 20 (1) ◽  
pp. 8 ◽  
Author(s):  
Aysar Talib Jarullah
Keyword(s):  
Ammonium Nitrate ◽  
Fluidized Bed ◽  
Chemical Engineering ◽  
Optimization Technique ◽  
Fluidized Bed Reactor ◽  
Operating Conditions ◽  
Optimal Operating ◽  
Two Phase ◽  
Zone Length ◽  
Engineering Research

<p>Due to the environmental legislations related to the nitrates and their emissions, thermal decomposition of ammonium nitrate (AN) in a fluidized reactor (FR) is regarded one of the most reasonable chemical-free disposal process for an aqueous waste nitrate stream. Therefore, the present study is aimed to improve a mathematical model based on experiments (from the literature) for enhancing the design of such reactor in an environmentally friendly manner. Where, the optimal kinetic parameters of the relevant reactions are firstly obtained employing the optimization technique keeping in mind the goal to construct the model with high exactness. Such design factors are then utilized for the purpose of getting the optimal operating conditions of fluidized bed reactor (FBR) achieving the main target of this process with ammonium nitrate-free content (Nil) at the end of the reactor in addition to reducing the NO<em><sub>x</sub></em><em> </em>emissions. The model is based on the two-phase theory of a FBR with predicting the concentration behavior along the reaction zone length for all components in the emulsion and bubble phases in addition to the temperature profile of the gas phase. New results related to output conversion of ammonium nitrate as well as NO content at the optimal operating conditions has been obtained in comparison with those reported in the literature.</p><p>Chemical Engineering Research Bulletin 20(2018) 8-18</p>

scholarly journals Hydrodynamics of a Novel Design Circulating Fluidized Bed Steam Reformer Operating in the Dense Suspension Upflow Regime

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Moataz Bellah M. Mousa ◽  
Seif-Eddeen K. Fateen ◽  
Essam A. Ibrahim
Keyword(s):  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Flow Characteristics ◽  
Homogeneous Catalyst ◽  
Reactor Performance ◽  
Two Phase ◽  
Dense Suspension ◽  
Fluidization Regime ◽  
Computational Fluid Dynamics Cfd ◽  
Steam Reformers

Circulating fluidized bed steam reformers (CFBSR) represent an important alternative for hydrogen production, a promising energy carrier. Although the reactor hydrodynamics play crucial role, modeling efforts to date are limited to one-dimensional models, thus ignoring many of the flow characteristics of fluidized beds that have strong effects on the reactor efficiency. The flow inside the riser is inherently complex and requires at least two-dimensional modeling to capture its details. In the present work, the computational fluid dynamics (CFD) simulations of the hydrodynamics of the riser part of a novel CFBSR were carried out using two-phase Eulerian-Eulerian approach coupled with kinetic theory of granular flow and K-ε model. Cold flow simulations were carried under different fluidization regimes. It was found that catalyst of Geldart's type “A” particle is more efficient for flow inside the catalytic reactor and dense suspension upflow (DSU) fluidization regime yields the best homogeneous catalyst distribution in the riser and thus best reactor performance. The optimum range for catalyst flux was found to be higher than 1150 kg/m2·s for a gas flux of 6.78 kg/m2·s. It was also noted that the value of 500 Kg/m2·s for catalyst flux represents the critical value below which the riser will operate under pneumatic transport regime.

scholarly journals Performances of continuous dryer with inert medium fluidized bed

2008 ◽  
Vol 62 (1) ◽  
pp. 13-24
Author(s):  
Zorana Arsenijevic ◽  
Zeljko Grbavcic ◽  
Radmila Garic-Grulovic
Keyword(s):  
Specific Heat ◽  
Fluidized Bed ◽  
Temperature Difference ◽  
Evaporation Rate ◽  
Operating Conditions ◽  
Heat Consumption ◽  
Water Evaporation ◽  
Isothermal Conditions ◽  
Inert Particles ◽  
Fluid Bed

A fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies according to the main efficiency criteria, i.e. specific water evaporation rate, specific heat consumption and speci?fic air consumption. A high drying efficiency results from the large con?tact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles leads to nearly isothermal conditions throughout the bed. A fluid bed dryer with inert particles was used for drying of slurries. Experiments were performed in a cylindrical column 215 mm in diameter with glass spheres as inert particles. In this paper, results of drying experi?ments with slurries of Zineb fungicide, copper hydroxide, calcium carbo?nate and pure water used as the feed material are presented. In our fluidized bed we successfully dried a number of other materials such as: fungicides and pesticides (Ziram, Propineb, Mangozeb, copper oxy-chloride, copper oxy-sulphate, Bordeaux mixture), other inorganic compounds (calcium sulphate, cobalt carbonate, electrolytic copper, sodium chloride), and a complex compound (organo-bentonite). The effects of operating conditions on dryer throughput and product quality were investigated. Main performance criteria, i.e. specific water evaporation rate, specific heat consumption and specific air consumption, were quantified. Temperature profile along the bed was mapped, and nearly isothermal conditions were found due to thorough mixing of the particles. Analysis of drying and energy efficiencies as a function of inlet and outlet air temperature difference was performed for deeper insight in dryer behavior and for optimizing dryer design and operation from an energy point of view. A simple mathematical model based on an overall heat balance predicts the dryer performance quite well. The industrial prototype with fluid bed of 0.8 m in diameter and capacity 650 kg of evaporated moisture per hour was realized on the basis of presented investigations on pilot unit. The most important results are 50% decrease in energy consumption and no-additional grinding of dried product in comparison with old tunnel drying technology.

scholarly journals Study on the Flow Characteristics of Desulfurization Ash Fine Particles in a Circulating Fluidized Bed

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1343
Author(s):  
Xiao Yang ◽  
Chengxiu Wang ◽  
Xingying Lan ◽  
Jinsen Gao
Keyword(s):  
Fluidized Bed ◽  
Flue Gas ◽  
Circulating Fluidized Bed ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Current Status ◽  
Circulation Rate ◽  
Wall Region ◽  
Gas Treatment ◽  
Solids Holdup

In view of the current status of catalytic cracking flue gas treatment, it is necessary to study the flow environment of desulfurization ash particles, which are a type of Geldart C particle, in a circulating fluidized bed (CFB) for semi-dry flue gas desulphurization using CFB technology. This study investigated the flow characteristics of desulphurization ash particles in a riser with an inner diameter of 70 mm and a height of 12.6 m, at a gas velocity of 4–7 m/s and a solids circulation rate of 15–45 kg/m2·s. The solids holdup in the axial distribution is relatively high near the bottom of the riser, and gradually decreases as the riser height increases, with a stable value from the middle to the top of the riser. In the radial distribution, the solids holdup of desulfurization ash particles is low in the center and high in the wall region. Within the above operating conditions, the solids holdup ranges from 0.008 to 0.025. The particle-based Archimedes number has a linear relationship with the solids holdup at all operating conditions.

scholarly journals Two-Way Coupling Simulation of Solid-Liquid Two-Phase Flow and Wear Experiments in a Slurry Pump

2022 ◽  
Vol 10 (1) ◽  
pp. 57
Author(s):  
Lei Jiang ◽  
Ling Bai ◽  
Peng Xue ◽  
Guangjie Peng ◽  
Ling Zhou
Keyword(s):  
Two Phase Flow ◽  
Volume Fraction ◽  
Volume Flow Rate ◽  
Pure Water ◽  
Solid Volume Fraction ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase ◽  
Solid Liquid

The slurry pump is one of the most important pieces of equipment in mineral transportation and separation systems, and it has complex two-phase flow characteristics and wear mechanisms. By employing numerical and experimental methods, the solid–liquid two-phase flow characteristics and wear patterns were investigated in this study. A two-way coupling discrete phase model (DPM) method was used to predict the flow pattern and the wear location and shows good agreement with the experimental observations. The pump performance characteristics of numerical results under pure water conditions were consistent with the experimental results. The effects of particle parameters and operating conditions on the internal flow field and wear were compared and discussed. The results show that the wear degree increased with the increase in volume flow rate and solid volume fraction. With the increase in particle size, the wear range at the impeller inlet became significantly smaller, but the wear degree became obviously larger. This study provides a basis for reducing the wear and improving the hydraulic performance of slurry pumps.

Heat Transfer Enhancement of a Three Phase Circulating Fluidized Bed Fruit Juice Evaporator Using Inert Particles

2011 ◽  
Vol 7 (2) ◽  
Author(s):  
Jitian Song ◽  
Jun Chi
Keyword(s):  
Heat Transfer ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Correlation Equation ◽  
Evaporation Process ◽  
Two Phase ◽  
Heat Transfer Efficiency ◽  
Three Phase ◽  
Inert Particles ◽  
Boiling Heat Transfer Coefficient

In this paper, pumpkin juice concentration was carried out using a three-phase circulating fluidized bed evaporator. The flow and heat transfer characteristics of the evaporation process were investigated and parametric studies were conducted to identify the governing parameters in the process. It was found that the heat transfer efficiency was improved by 35 percent through addition of the inert particles into the two-phase evaporation process. Inert particles also inhibited the forming of fouling during the pumpkin juice concentration. A correlation equation of the boiling heat transfer coefficient was established for the three-phase circulating fluidized bed evaporator. This work improves the understanding of the three-phase circulating fluidized bed evaporator, which is beneficial to its wider application in the foodstuff processing field.

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