Experimental Investigation on Flow Patterns of Cylindrical-Conical Spout-Fluidizing Bed

2011 ◽  
Vol 354-355 ◽  
pp. 338-343
Author(s):  
Qian Jun Li ◽  
Dong Ping Zhang
Keyword(s):  
Flow Pattern ◽  
Fluidized Bed ◽  
Fixed Bed ◽  
Ccd Camera ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Hydrodynamic Characteristics ◽  
Experimental Investigations ◽  
Bed Height ◽  
Bed Materials

Experimental investigations on hydrodynamic characteristics of cylindrical pressurized spout-fluidizing bed were carried out. Two kinds of millet were used as bed materials. The operational pressure is 0.1MPa~0.4MPa (absolutely pressure). Five distinct flow patterns, i.e, fixed bed(FB), jet in fluidized bed with bubbles(JFB), jet in fluidized bed with slugging(JFS), spout with aeration(SA) and spout-fluidizing bed(SF) were identified. Effects of the static bed height and operational pressure on the flow pattern map were particularly studied. Typical flow pattern images obtained by a high- resolution digital CCD camera were presented for classifying these flow patterns. Typical flow pattern maps were plotted for describing the transitions between flow patterns with operating conditions

Comparative Bio-sorption of Cadmium and Nickel Ions from Aqueous Solution onto Fibers of Date Palm using Fluidized Bed Column

2019 ◽  
Vol 70 (5) ◽  
pp. 1507-1512
Author(s):  
Baker M. Abod ◽  
Ramy Mohamed Jebir Al-Alawy ◽  
Firas Hashim Kamar ◽  
Gheorghe Nechifor
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Metal Ions ◽  
Fluidized Bed ◽  
Removal Efficiency ◽  
Heavy Metal Ions ◽  
Date Palm ◽  
Operating Conditions ◽  
Initial Concentration ◽  
Bed Height

The aim of this study is to use the dry fibers of date palm as low-cost biosorbent for the removal of Cd(II), and Ni(II) ions from aqueous solution by fluidized bed column. The effects of many operating conditions such as superficial velocity, static bed height, and initial concentration on the removal efficiency of metal ions were investigated. FTIR analyses clarified that hydroxyl, amine and carboxyl groups could be very effective for bio-sorption of these heavy metal ions. SEM images showed that dry fibers of date palm have a high porosity and that metal ions can be trapped and sorbed into pores. The results show that a bed height of 6 cm, velocity of 1.1Umf and initial concentration for each heavy metal ions of 50 mg/L are most feasible and give high removal efficiency. The fluidized bed reactor was modeled using ideal plug flow and this model was solved numerically by utilizing the MATLAB software for fitting the measured breakthrough results. The breakthrough curves for metal ions gave the order of bio-sorption capacity as follow: Cd(II)]Ni(II).

scholarly journals IMPROVE THE PYROLYTIC GAS PRODUCTION BY USING THE CO-PYROLYSIS TECHNIQUE : AN EXPERIMENTAL STUDY

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Abo . Zahra A.I ◽  
M.K. Abd El- Wahab ◽  
M.A. Tawfik
Keyword(s):  
Energy Conversion ◽  
Fluidized Bed ◽  
Conversion Efficiency ◽  
Fixed Bed ◽  
Energy Conversion Efficiency ◽  
Gas Production ◽  
Operating Conditions ◽  
Energy Unit ◽  
Heating Value ◽  
Slow Pyrolysis

The target of the biomass co-pyrolysis is improvingthe heating value of the produced bio-products of a certain type of feedstock, besides disposal of more than one residue in the same time. Thus, this work aims to operate a local fabricated fixed-bed pyrolyzer to improve the pyrolytic gas yield produced by the ground pieces of three biomass residues namely Mango trees Pruning Logs (MPL), Sugarcane bagasse (SB) and Rice straw (RS) using an affordable slow pyrolysis technique. This work was carried out under slow pyrolysis conditions represented in final pyrolysis temperature of 400 °C, vapor residence time of 4 min, heating rate of 0.01-1 °C/s in full absence of oxygen. The pyrolytic gas production was assessed under different feedstock mixing ratios of (1:2:1), (1:1:2) and (2:1:1) as ratio of (RS: SB: MPL), particle lengths of 1-5, 10-15 and 20-25 mm, with and without sandy bed at the bottom of pyrolysis chamber as a fluidized bed. The obtained results showed that, using the fluidized fixed-bed pyrolyzer under slow co-pyrolysis conditions gave the optimum results where in, the pyrolytic gas concentration, gas yield, higher heating value of pyrolytic gasand energy conversion efficiency were 55%, 1.09 Nm3 /kg, 14.97 MJ/Nm3 and 85.43%, respectively, and 53.7%, 1.08 Nm3 /kg, 13.75 MJ/Nm3 ,77.71% in case of using the pyrolyzer without fluidized bed under the same operating conditions. So, the pyrolyzer with fluidized bed achieves an increment in the higher heating value and energy conversion efficiency by about 8.15% and 9.03%, respectivly over the pyrolyzer without fluidized bed.Furthermore, the cost per energy unit of pyrolytic gas produced by the fluidized bed pyrolyzer is lower than the common two fossil gaseous fuels of natural gas and LPG costs by about 28.57% and 80%, respectively.

Unified Model for Gas-Liquid Pipe Flow Via Slug Dynamics: Part 1 — Model Development

2002 ◽  
Author(s):  
Hong-Quan Zhang ◽  
Qian Wang ◽  
Cem Sarica ◽  
James P. Brill
Keyword(s):  
Flow Pattern ◽  
Pipe Flow ◽  
Slug Flow ◽  
Control Volume ◽  
Model Development ◽  
Flow Patterns ◽  
Hydrodynamic Characteristics ◽  
Momentum Exchange ◽  
Two Phase ◽  
Inclination Angles

A unified hydrodynamic model is developed for predictions of flow pattern transitions, pressure gradient, liquid holdup and slug characteristics in gas-liquid pipe flow at different inclination angles from −90 to 90 deg. The model is based on the dynamics of slug flow, which shares transition boundaries with all the other flow patterns. By use of the entire film zone as the control volume, the momentum exchange between the slug body and the film zone is introduced into the momentum equations for slug flow. The equations of slug flow are used not only to calculate the slug characteristics, but also to predict transitions from slug flow to other flow patterns. Significant effort has been made to eliminate discontinuities among the closure relationships through careful selection and generalization. The flow pattern classification is also simplified according to the hydrodynamic characteristics of two-phase flow.

The flow patterning capability of localized natural convection

2016 ◽  
Vol 18 (36) ◽  
pp. 25380-25387 ◽  
Author(s):  
Ling-Ting Huang ◽  
Ling Chao
Keyword(s):  
Natural Convection ◽  
Flow Pattern ◽  
State Diagram ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Heat Sources

Controlling flow patterns to align materials can have various applications in optics, electronics, and biosciences. We developed a natural-convection-based method to create desirable spatial flow patterns by controlling the locations of heat sources and proposed a flow pattern state diagram which suggests a suitable range of operating conditions for flow patterning.

scholarly journals Fixed-bed Column Dynamics of Ultrasound and Na-functionalized Diatomite to Remove Phosphate from Water

2021 ◽  
Author(s):  
Junxiu Ye ◽  
Min Yang ◽  
Xuemei Ding ◽  
Wei Tan ◽  
Guizhen Li ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Correlation Coefficients ◽  
Operating Conditions ◽  
Phosphate Adsorption ◽  
Breakthrough Time ◽  
Fixed Bed Column ◽  
Bed Height ◽  
Column Dynamics ◽  
Phosphorous Concentration ◽  
Column Process

Abstract A continuous fixed-bed column study has been used to evaluate phosphate adsorption performance of U-D-Na which was functionalized by the cheap NaCl reagent after simple ultrasonic purification of diatomite. Experimentally, various effect factors, the flow rate, the initial phosphate concentration, and the bed height on breakthrough time of fixed column were studied. Experimental results showed that the breakthrough time declined with the increase of inlet phosphorous concentration and feed rate, whereas the increase of bed height turned out to significantly prolong the breakthrough time. The dynamic adsorption data could better be fitted by the Thomas model, with the correlation coefficients obtained, R2 > 0.9000 at the majority of operating conditions (5/7). At least thrice loop of adsorption and desorption was achieved with 0.1 M hydrochloric acid eluent and deionized water. The results proved that U-D-Na could be used as a better alternative phosphate adsorbent from wastewater in a continuous column process.

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.

Characterization and Utilization of a Commercial Clay for Ammonia Adsorption Influence of Operating Parameters on Gas Retaining

2008 ◽  
Vol 59 (10) ◽  
Author(s):  
A. Violeta Ursu ◽  
Fabrice Gros ◽  
Denisa I. Nistor ◽  
Gholamreza Djelveh
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Operating Parameters ◽  
Clay Layer ◽  
Natural Clay ◽  
Ammonia Adsorption ◽  
Sodium Bentonite ◽  
Nh3 Adsorption

The aim of this paper is to study the use of a mixture of commercial clay namely K10 and a natural Romanian sodium bentonite in the adsorption of NH3 contained in air using fixed and fluidized bed gas-solid reactors. Qualitative (DRX) and quantitative (XPS, DTG) analysis were performed. Clays were agglomerated and treated with NH3. Adsorption isotherms were determined under several operating conditions. Results showed that after 70 minutes of ammonization, activated agglomerated clay exhibits a superior capacity of adsorption (2.09 mmoles NH3/g clay instead of 1.057 mmoles/g clay for natural clay). The saturation duration depends on the adsorbent bed state (fixed or fluidized bed). The mass transfer is better in fluidized bed, the clay layer being saturated more rapidly compared to the fixed bed.

Different Exit Effects between a Combined Riser with Variable Exit Constraints and a Conventional Riser with Weak Exit Constraints

2012 ◽  
Vol 550-553 ◽  
pp. 529-533
Author(s):  
De Wu Wang ◽  
Meng Da Jia ◽  
Shao Feng Zhang ◽  
Chun Xi Lu
Keyword(s):  
Fluidized Bed ◽  
Particle Velocity ◽  
Large Scale ◽  
Operating Conditions ◽  
Wall Region ◽  
Cold Model ◽  
Linear Distribution ◽  
Cross Sectional ◽  
Bed Height ◽  
Solids Holdup

A large-scale cold model experimental setup of combined riser with variable constraint exit (CRVCE) was established. The axial and radial distributions of solids holdup and particle velocity, under different operating conditions, were investigated experimentally, and the results were compared with conventional riser (CR). Experimental results showed that, the exit restrictive effect of combined riser with variable constraint exit was weak when particle circulation flux and static bed height in upper fluidized bed were lower, while it turned to be strong when superficial gas velocity and static bed height in upper fluidized bed were higher. Under the same conditions, averaged cross-sectional solids holdup of CRVCE was characterized by C type distribution when article circulation flux was higher, while that of CR with weak constraint exit was characterized by linear distribution. In axial direction, averaged cross-sectional particle velocity of CRVCE changed in order: acceleration-constant-decrease velocity, while that of CR changed in another: acceleration-constant velocity. The maximum of local solids holdup value of CRVCE appeared at the dimensionless radius position r/R=0.7, while that of CR appeared in the wall region. Their local particle velocities were similar in the core region, while local particle velocity of CRVCE was lower than that of CR in the annular region.

scholarly journals Biological treatment of water contaminated by hydrocarbons in three-phase gas-liquid-solid fluidized bed

2013 ◽  
Vol 8 (1) ◽  
pp. 9-15
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Biological Treatment ◽  
Plug Flow ◽  
Point Of View ◽  
Operating Conditions ◽  
Solid Particles ◽  
Hydrodynamic Characteristics ◽  
Intimate Contact ◽  
Three Phase

Biological treatment has been carried out in two different systems: aerated closed and threephase fluidized bed reactors for hydrocarbons removal from refinery wastewaters. For the two systems, hydrodynamic study allowed the determination of operating conditions before treatment experiments. Then, in a second time, biological treatments have been conducted in the same operating conditions. The obtained results showed that in the three-phase fluidized bed we can degrade hydrocarbons more rapidly than in a closed aerated bioreactor. Among the different appropriate techniques available to create efficient contacts between phases, the three-phase fluidization G/L/S where carrier particles are moving inside the reactor seems very interesting. It allows an intimate contact between phases and present many advantages concerning hydrodynamic and mass transfer phenomena. In fact, depending on operating conditions and the bubble flow behaviour, the three-phase fluidized bed could display different flow regimes In these systems called bioreactors the solid particles covered with a biofilm are fluidized by two ascending flows of air and contaminated water. With favourable operating conditions, from a hydrodynamic and mass transfer point of view, the pollutant can be biologically degraded up to 90%. Until this date, the three-phase bioreactors modelling remains very complex because it required taking into account several factors: the pollutant biodegradation rate in the biofilm, the bioreactor hydrodynamic characteristics, and the reactant interfacial gas-liquid and liquidsolid mass transfer. Thus the essential purpose of modelling is to integrate the microbial kinetics with the reactor hydrodynamics. We can notice that a few models have incorporated both bioreactor hydrodynamics and microbial kinetics. For the steady state bioreactor model, we generally assume that the particles are uniform in size, the biofilm is uniform in thickness, and the biofilm can be considered as homogeneous matrix through which oxygen and substrate diffuse and are consumed by the microbes. The liquid phase in the bioreactor substrate is considered to be axially dispersed while the gas phase is assumed to be in plug flow [2]. Rittmann (1997) proposed a model based on wake theory for predicting bed expansion and phase hold-ups for three-phase fluidized bed bioreactors. In this model he modified the correlation for the computation of the bioparticles drag coefficient CD [3]. He also attempted to explain the biofilm detachment which can occur with three broad patterns: erosion, sloughing and scouring and assumed that the factors affecting detachment rates can be grouped into two categories (physical forces and microorganisms physiology in the biofilm).

Sign in / Sign up

Export Citation Format

Share Document