scholarly journals Drying of suspension and pastes in fluidized bed of inert particles

2000 ◽  
Vol 65 (12) ◽  
pp. 963-974 ◽  
Author(s):  
Zeljko Grbavcic ◽  
Zorana Arsenijevic ◽  
Radmila Garic-Grulovic
Keyword(s):  
Pure Water ◽  
Operating Conditions ◽  
Raw Material ◽  
Water Evaporation ◽  
Large Temperature ◽  
Attractive Alternative ◽  
Mechanical Agitation ◽  
Inert Particles ◽  
Fluid Bed ◽  
Drying Efficiency

A fluid bed dryer with inert particles was used for the drying of suspensions and pastes. The effects of the operating conditions on the dryer throughput and on the product quality were investigated. Experiments were performed in a cylindrical column 215 mm in diameter and 1200 mm in height with 0.925 mm diameter glass spheres as the fluidizing media. Cineb fungicide, copper hydroxide and pure water were used as the feed material. With respect to the main efficiency criteria, i.e., specific water evaporation rate, specific heat consumption and specific air consumption, a fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies. A high drying efficiency results from the large contact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles, due to aggregative fluidization and mechanical agitation, leads to nearly isothermal conditions throughout the bed. In our experiments, suspensions and very dense pastes were successfully treated. Suspension and product hold-up in the bed varies between 6 and 8 % by mass and a product with the same particle size as the raw material is obtained.

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 Hydrothermal Corrosion Behaviors of Constituent Materials of SiC/SiC Composites for LWR Applications

Ceramics ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 602-611
Author(s):  
Shoko Suyama ◽  
Masaru Ukai ◽  
Megumi Akimoto ◽  
Toshiki Nishimura ◽  
Satoko Tajima
Keyword(s):  
Corrosion Resistance ◽  
Residual Strength ◽  
Pure Water ◽  
Operating Conditions ◽  
Raw Material ◽  
Stoichiometric Ratio ◽  
Sic Fibers ◽  
Corrosion Behaviors ◽  
Fiber Matrix ◽  
Sic Composites

The corrosion behaviors of SiC/SiC composite constituent materials in pure water at operating conditions, such as 300 °C and 8.5 MPa, were studied for potential application in accident-tolerant light water reactor (LWR) fuel cladding and core structures. Five kinds of SiC fibers, four kinds of SiC matrices, and three kinds of fiber/matrix interphase materials were examined in autoclaves. The potential constituent materials for future use in SiC/SiC composites were selected by considering corrosion rates and residual strength characteristics. The mass changes and the residual strength of each specimen were measured. SEM images of the surface layers were also inspected. The SiC fibers, regardless of their purity, crystallinity or stoichiometric ratio, decreased in strength due to the hydrothermal corrosion. For its part, the hydrothermal corrosion resistance of CVD-SiC, as a SiC matrix, was found to be affected by manufacturing conditions such as raw material gas type and synthesis temperature, as well as post-machining morphology. The CVD-carbon (CVD-C), as a fiber/matrix interphase material, showed good hydrothermal corrosion resistance. In order to protect the SiC fibers and the SiC matrices from hydrothermal corrosion, it would appear to be necessary to apply a dense CVD-C coating to both every fiber and the entire surface of the SiC matrices.

Drying Model of Paste Materials in Fluidized Bed with Inert Particles and Immersed Heating Tubes

2011 ◽  
Vol 412 ◽  
pp. 463-468
Author(s):  
Bi Qiang Yao ◽  
Xue Jun Zhu
Keyword(s):  
Fluidized Bed ◽  
High Viscosity ◽  
Water Evaporation ◽  
Low Dissipation ◽  
Inert Particles ◽  
Drying Technology ◽  
Drying Properties ◽  
Drying Conditions ◽  
Drying Efficiency ◽  
Equipment Size

The mechanism of drying paste materials was investigated in a fluidized bed with inert particles and inner heats. A mathematical model is proposed to predict the specific water evaporation. The drying properties of dryer can be predicted based on the correlation equations. The drying of paste CaCO3materials was industrial-mode experimentally carried out in a fluidized bed with inert particles and immersed heating tubes. The paste material was spray droplet in sizes range of 200~400μm with pressure nozzles or air-blast nozzles, and spray to the surface of inert particles, and the feasible drying conditions were researched. The feasible drying parameters, operation parameters and equipment parameters were researched. The results show that this drying technology can be enhanced the heat transfer and the paste materials of high viscosity can be effectively distributed into the fluidized bed, well distributed temperature in beds, large elasticity of operation, the low energy consumption. The new drying equipment has high drying capacity, small equipment size. The results can provide important meaning on theory and instructing practice for developing the new drying technology with high drying efficiency and low dissipation of energy.

scholarly journals High efficiency disperse dryer - an innovative process for drying of solutions, suspensions and pastes in a fluidized bed of inert particles

2019 ◽  
Vol 73 (4) ◽  
pp. 213-222
Author(s):  
Mihal Djuris ◽  
Tatjana Kaludjerovic-Radoicic ◽  
Darko Jacimovski ◽  
Zorana Arsenijevic
Keyword(s):  
Fluidized Bed ◽  
High Efficiency ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Performance Criteria ◽  
Water Evaporation ◽  
Fluidized Bed Dryer ◽  
Glass Spheres ◽  
Innovative Process ◽  
Inert Particles

In this paper, an innovative fluidized bed dryer with inert particles is presented. The system can be used for drying of solutions, suspensions and pastes in order to obtain a powdered product. The experiments were performed in a pilot-scale dryer with a cylindrical column 0.215 m in diameter and 1.2 mm height, with glass spheres as inert particles. The material used for drying was CuSO4 solution. The effects of operating conditions on the 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. Nearly isothermal conditions were found due to thorough mixing of the particles. The energy efficiency of the dryer was also assessed. Simple heat and mass balances predicted the dryer performance quite well.

scholarly journals Drying of solutions and suspensions in the modified spouted bed with draft tube

2002 ◽  
Vol 6 (2) ◽  
pp. 47-70 ◽  
Author(s):  
Zorana Arsenijevic ◽  
Zeljko Grbavcic ◽  
Radmila Garic-Grulovic
Keyword(s):  
Draft Tube ◽  
Pure Water ◽  
Inorganic Compound ◽  
Operating Conditions ◽  
Rate Equations ◽  
Spouted Bed ◽  
Two Phase ◽  
Inert Particles ◽  
Polyethylene Particles ◽  
Drying Model

A modified spouted bed dryer with inert particles was used for drying of solutions and suspensions. The effects of the operating conditions on dryer throughput and product quality were investigated. Experiments were performed in a cylindrical column 215 mm in diameter and 1150 mm in height with a draft tube 70 mm in diameter and 900 mm length. The bed was made of polyethylene particles 3.3 mm in diameter and of density of 921 kg/m3. The pesticide Cineb, inorganic compound calcium carbonate, organic compound calcium stearate, and pure water were used as feeding materials. A drying model using the continuity and momentum equations for turbulent accelerating two-phase flow and conventional rate equations is proposed and discussed. The work is relevant for estimating dryer performance.

scholarly journals Tagasaste, leucaena and paulownia: three industrial crops for energy and hemicelluloses production

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alberto Palma ◽  
Javier Mauricio Loaiza ◽  
Manuel J. Díaz ◽  
Juan Carlos García ◽  
Inmaculada Giráldez ◽  
...  
Keyword(s):  
Activation Energy ◽  
Acid Hydrolysis ◽  
Energy Production ◽  
Combustion Process ◽  
Operating Conditions ◽  
Raw Material ◽  
Energy Of Combustion ◽  
Increasing Temperature ◽  
Hydrolysis Of ◽  
Chamaecytisus Proliferus

Abstract Background Burning fast-growing trees for energy production can be an effective alternative to coal combustion. Thus, lignocellulosic material, which can be used to obtain chemicals with a high added value, is highly abundant, easily renewed and usually inexpensive. In this work, hemicellulose extraction by acid hydrolysis of plant biomass from three different crops (Chamaecytisus proliferus, Leucaena diversifolia and Paulownia trihybrid) was modelled and the resulting solid residues were used for energy production. Results The influence of the nature of the lignocellulosic raw material and the operating conditions used to extract the hemicellulose fraction on the heat capacity and activation energy of the subsequent combustion process was examined. The heat power and the activation energy of the combustion process were found to depend markedly on the hemicellulose content of the raw material. Thus, a low content in hemicelluloses resulted in a lower increased energy yield after acid hydrolysis stage. The process was also influenced by the operating conditions of the acid hydrolysis treatment, which increased the gross calorific value (GCV) of the solid residue by 0.6–9.7% relative to the starting material. In addition, the activation energy of combustion of the acid hydrolysis residues from Chamaecytisus proliferus (Tagasaste) and Paulownia trihybrid (Paulownia) was considerably lower than that for the starting materials, the difference increasing with increasing degree of conversion as well as with increasing temperature and acid concentration in the acid hydrolysis. The activation energy of combustion of the solid residues from acid hydrolysis of tagasaste and paulownia decreased markedly with increasing degree of conversion, and also with increasing temperature and acid concentration in the acid hydrolysis treatment. No similar trend was observed in Leucaena diversifolia (Leucaena) owing to its low content in hemicelluloses. Conclusions Acid hydrolysis of tagasaste, leucaena and paulownia provided a valorizable liquor containing a large amount of hemicelluloses and a solid residue with an increased heat power amenable to efficient valorization by combustion. There are many potential applications of the hemicelluloses-rich and lignin-rich fraction, for example as multi-components of bio-based feedstocks for 3D printing, for energy and other value-added chemicals.

Ultimate Elastic Wall Stress (UEWS) Test under Biaxial Loading for Glass-Fibre Reinforced Epoxy (GRE) Pipes

2014 ◽  
Vol 974 ◽  
pp. 188-194 ◽  
Author(s):  
Tarak A. Assaleh ◽  
Lutfeya A. Almagguz
Keyword(s):  
Biaxial Loading ◽  
Pipe Wall ◽  
Axial Stress ◽  
Wall Stress ◽  
Current Method ◽  
Raw Material ◽  
Attractive Alternative ◽  
Filament Wound ◽  
Elastic Wall ◽  
Filament Wound Composite

This paper presents the results of an experimental investigation into the Ultimate Elastic Wall Stress (UEWS) of ±55° filament wound composite pipes. The UEWS test appears to provide an attractive alternative to the current method, and has proved to be one of the most effective in term of accuracy and speed. Moreover, it has been found to be sensitive to changes in key manufacturing and raw material parameters. The pipes were subjected to biaxial loading, which was achieved by combinations of hoop and axial stress. Loads were applied as groups of cycles which, were gradually increased until the UEWS had been determined. Various ratios of hoop to axial stress were applied to the pipes, ranging from pure axial to pure hoop loading at room temperature and at 65°C. These ratios were investigated by applying different pressures in both the main and small chambers built inside the pipe, and therefore it was unnecessary to add any external loads to the pipe wall. Tests were also conducted to observe leakage through the pipe wall. The main failure mode observed was weepage through the pipe wall, which was due to intensive matrix microcracking. The results from the UEWS tests are presented in the form of failure envelopes showing the effects of testing at an elevated temperature. Finally, degradation in the elastic properties of the pipe wall is also discussed and plotted against wall stress.

Agglomeration Technologies of Processing Powder Wastes

2015 ◽  
Vol 244 ◽  
pp. 121-129
Author(s):  
Marian Peciar ◽  
Roman Fekete ◽  
Peter Peciar
Keyword(s):  
Research Work ◽  
Operating Conditions ◽  
Airborne Particles ◽  
Raw Material ◽  
Production Cycle ◽  
Shear Forces ◽  
Material Resources ◽  
New Type ◽  
Two Phases ◽  
High Technologies

This article deals with the presentation of modern applications for processing powdered, primarily hazardous, waste to an agglomeration form appropriate for subsequent processing by classical methods, for example in the construction, automotive and consumer goods industries. The aim of the research work was to set appropriate operating conditions in order to appreciate currently non-processable wastes resulting from the intensive production of often extremely expensive materials. Technologies which enable returning powder waste back into the primary production cycle were developed and experimentally tested, thus saving raw material resources. When necessary for the fixing of fine airborne particles with a problematic compacting curve (hard to compress, repulsive due to the surface charge) extrusion processes using a patented technology enabling controlled modification of shear forces in the extrusion zone were successfully applied. A new type of axial extruder allows the elimination of the liquid phase and as a result prevents the clogging of the extrusion chamber. In the case of need for granulation of sensitive materials (for example pharmaceuticals not allowing the addition of any kind of agglomerating fluid or reacting strongly in the contact of the two phases), a process of compaction between rolls with different profiled surface was successfully applied. The developed high technologies and the resulting products thus represent a major contribution to environmental protection in the context of not only the work but also the communal environment.

The Influence of Lubricant Supply Conditions and Bearing Configuration on the Performance of (Semi) Floating Ring Bearing Systems for Turbochargers

2017 ◽  
Author(s):  
Luis San Andrés ◽  
Feng Yu ◽  
Kostandin Gjika
Keyword(s):  
Heat Flow ◽  
Thermal Energy ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Engine Oil ◽  
Large Temperature ◽  
Oil Viscosity ◽  
Supply Pressure ◽  
The Impact ◽  
Bearing System

Engine oil lubricated (semi) floating ring bearing (S)FRB systems in passenger vehicle turbochargers (TC) operate at temperatures well above ambient and must withstand large temperature gradients that can lead to severe thermo-mechanical induced stresses. Physical modeling of the thermal energy flow paths and an effective thermal management strategy are paramount to determine safe operating conditions ensuring the TC component mechanical integrity and the robustness of its bearing system. On occasion, the selection of one particular bearing parameter to improve a certain performance characteristic could be detrimental to other performance characteristics of a TC system. The paper details a thermohydrodynamic model to predict the hydrodynamic pressure and temperature fields and the distribution of thermal energy flows in the bearing system. The impact of the lubricant supply conditions (pressure and temperature), bearing film clearances, oil supply grooves on the ring ID surface are quantified. Lubricating a (S)FRB with either a low oil temperature or a high supply pressure increases (shear induced) heat flow. A lube high supply pressure or a large clearance allow for more flow through the inner film working towards drawing more heat flow from the hot journal, yet raises the shear drag power as the oil viscosity remains high. Nonetheless, the peak temperature of the inner film is not influenced much by the changes on the way the oil is supplied into the film as the thermal energy displaced from the hot shaft into the film is overwhelming. Adding axial grooves on the inner side of the (S)FRB improves its dynamic stability, albeit increasing the drawn oil flow as well as the drag power and heat flow from the shaft. The predictive model allows to identify a compromise between different parameters of groove designs thus enabling a bearing system with a low power consumption.

Natural Convection in an Enclosure With Blend of Micro Encapsulated Phase Change Materials

2013 ◽  
Author(s):  
Yasmin Khakpour ◽  
Jamal Seyed-Yagoobi
Keyword(s):  
Heat Transfer ◽  
Thermal Expansion ◽  
Natural Convection ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Numerical Study ◽  
Pure Water ◽  
Operating Conditions ◽  
Effective Density

This numerical study investigates the effect of using a blend of micro-encapsulated phase change materials (MEPCMs) on the heat transfer characteristics of a liquid in a rectangular enclosure driven by natural convection. A comparison has been made between the cases of using single component MEPCM slurry and a blend of two-component MEPCM slurry. The natural convection is generated by the temperature difference between two vertical walls of the enclosure maintained at constant temperatures. Each of the two phase change materials store latent heat at a specific range of temperatures. During phase change of the PCM, the effective density of the slurry varies. This results in thermal expansion and hence a buoyancy driven flow. The effects of MEPCM concentration in the slurry and changes in the operating conditions such as the wall temperatures compared to that of pure water have been studied. The MEPCM latent heat and the increased volumetric thermal expansion coefficient during phase change of the MEPCM play a major role in this heat transfer augmentation.

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