Materials Science Forum Vol. 802

Abstract: In industries that work with particulate material is observed from among other concerns, not to discard solid material in the air. Aiming to develop gas-solid filtration equipment more efficient, the study of a self-cleaning system utilizing filter fabric made ​​from synthetic material, was conducted using the phosphate rock as particulate material. The objective of this study is to evaluate the performance of a vibratory system filtration of gases. The system is made up a box filter coupled to an eccentric motor which causes a continuous vibration during the filtration cycle, not being necessary to interrupt the process to the procedure of fabric filter cleaning. We used polyester synthetic filter for the tests. With known relative humidity and temperature at which the tests were performed, it was possible to estimate the performance of the equipment in continuous vibration filtration of pulverulent material dispersed in gas currents, under the influence of different vibration frequencies.

Abstract: Although the construction, maintenance and operation of hydrocyclones is simple in nature, it is known that the hydrodynamic behavior inside hydrocyclones is quite complex. Among the features which confer this complexity stands out: high vorticity preservation, vortex breakdown, flow inversion, and the possibility of formation of air core due to the generation of a low pressure area in the central axis of the separator. In this sense this work aimed to study the hydrodynamics of a hydrocyclone using as tool the Computational Fluid Dynamics (CFD). The simulated results were obtained considering two different models for turbulence: Reynolds stress model and Large Eddy simulation methodology. Can be highlighted as main simulated variables the flow ratio and the pressure drop of the hydrocyclone, which were compared with experimental values. In order to evaluate the influence of air core on the simulated variables, were done numerical simulations of the hydrocyclone operating in the presence of air core, using for this, the volume of fluid (VOF) model.

Abstract: In this study, different compositions based on rice husk carbon and kaolinitic clay aimed at obtaining ceramic filter were studied. Three compositions of 40, 60 and 80% rice husk of the total mass were prepared. The specimens were uniaxially compressed in rectangular shape at pressure of 28 MPa and were sintered at temperatures of 1100oC, 1150oC and 1200oC for 1 h. The sintered samples were characterized according to standard technique for linear shrinkage, water absorption, apparent porosity and flexural strength. Scanning Electron Microscopy (SEM) was also performed to check the average pore size, and X-Ray Diffraction (XRD) to verify existing crystalline phases, chemical analysis and mercury porosimetry. The X-ray diffraction results showed mostly alpha quartz peaks and mullite after sintering. Mercury porosimetry showed porosity of 44.33% and average pore size of approximately 8.33 μm for sample with 60% rice husk sintered at 1200°C.

Abstract: The fast pyrolysis is an efficient and promising process of thermal decomposition. The process consists in the reaction of organic materials in the total or partial absence of oxygen to produce condensable vapor, non-condensable gases and char. Bio-oil is generated after vapor condensation and it can be converted into fuels and/or chemicals. Fast pyrolysis of soy hulls was conducted in a batch reactor fluidized bed, made of stainless steel, with internal diameter of 78 mm and 1069 mm height. The fast pyrolysis of soy hulls, mixed with inert (sand), was carried out at approximately 550 °C. Atmosphere with high nitrogen concentration was used. The present study aimed to investigate the chemical composition of the soy hulls bio-oil using gas chromatography and mass spectrometry techniques.

Abstract: Hydrocyclones are equipments widely used in solid-liquid separation, as in mineral, chemical, petrochemical, textile, and metallurgical industries. The suitable choice of its dimensions depends on the process main objective. There is the case that the major interest is to concentrate a suspension, either to discard the dispersed phase (solids) or to use it. The objective of this work was to study, experimentally, a filtering hydrocyclone with a suitable geometry that provides a low underflow-to-throughput ratio, i.e., that produces a thick underflow. The effect of the underflow orifice diameter in the equipment performance was evaluated. The results showed that the smallest orifice size produced an underflow stream with concentration upper than 45% in volume.

Abstract: Hydrocyclones are equipments that separate a discrete phase (solid, liquid or gas) from a continuous phase (liquid) by generating a centrifugal field. The objective of this work was to study, experimentally, the incorporation effect of cylindrical and conical permeable walls (CyCoFH) on an optimized geometry hydrocyclone (H11) to evaluate the equipment’s processing capacity. By inserting a filtering cone and cylinder, during the operation of these separators, besides the traditionally observed streams (underflow and overflow), there is an additional liquid stream resulting from the filtering process in the conical and cylindrical regions. Despite the low filtrate flow observed during this new equipment’s operation, it was found that the filtration is benefic to hydrocycloning. According to the main results, the CyCoFH hydrocyclone of lower permeability presented a greater processing capacity. The feed flow rate was 23% higher than the corresponding conventional hydrocyclone, in the same geometrical and operational conditions.

Abstract: Hydrocyclones are separators that are widely used in industry that belong to an important group of equipments designed to solid-liquid or liquid-liquid separation. The employment of hydrocyclones is generally restricted to an equipment need with a high classifying power (based on the size of particles collected in the underflow) or with a high concentrating capacity. The separation occurs by density difference or particle size distribution of the dispersed phase. In order to maximize the separation efficiency of these devices, the aim of this work was to study experimentally the consequences of an unusual feed in the behavior of a hydrocyclone. Therefore, tests were carried out with aqueous suspensions of phosphate rock at a fixed level of pressure drop equal to 1.47 bar, using the optimized geometry hydrocyclone H11. The influence of the so called rotating feed inlet for the H11 was evaluated in clockwise and anticlockwise. Experimental studies have suggested that the rotation of the fluid in the feed inlet of hydrocyclone did not change significantly the underflow-to-throughput ratio (RL), although it has caused changes in the energy cost and in the performance of the separator.

Abstract: Oil companies have increasingly invested in alternative technologies for cuttings treatment. The research for new operations or equipments leads to investigate the properties and characteristics of drilled cuttings and drilling fluids. This work presents the physical characterization of cuttings, drilling fluid and organic phase recoved after cuttings drying. It was carried out analysis of rheology for the drilling fluid and particle size and shape for the cuttings. Considering the microwave drying technology, which has been investigated for cuttings treatment, it was also determined the dielectric properties for the drilling fluid. The quality of the organic phase recovered in the microwave cuttings drying was also analysed.

Abstract: The use of recycled water in the apatite flotation may result in losses to the process performance due to the presence of ions, residual reagents, finely particulate material, etc. The dissolved air flotation (DAF) has been shown an efficient technique in the wastewater treatment in the removal of these pollutants. The use of anionic collector in DAF process is based on the reaction that occurs between the soybean oil soap (apatite collector) with the calcium present in the apatite lattice making its surface hydrophobic. Therefore, the collector can be an auxiliary in the water softening besides improving the hydrophobicity of the particles to be collected. Thus, this study was aimed at evaluating the effect of an anionic collector used as an auxiliary in the dissolved air flotation process. A central composite design (CCD) was proposed to evaluate the concentration of collector and the effect of pH value on the removal efficiency of calcium, magnesium, fluoride, phosphorous and turbidity present in a wastewater from a fertilizer industry. The results showed a good removal of the contaminants which guaranteed a better quality of water to the process of phosphate rock concentration.

Abstract: The study of filtration and thickening of particulate systems are used in many industrial processes involving processes of solid-liquid separation, such as in sedimentation ponds, filters, the drilling of oil wells, among others. This paper aims to advance the empirical mechanisms involved in the processes of solid-liquid separation and obtain constitutive equations relating the pressure in solids and porous media permeability from non-Newtonian fluids. In the experiments used aqueous solutions of xanthan gum concentration of 0.1% in weight basis in order to ensure non-newtonian means. For the preparation of suspensions, was used calcium carbonate as particulate material in the separation process involved an initial concentration of 12% by volume. The concentrated sediment was maintained between 30 and 48% by volume. Settling tests were carried to term and sediments resulting from each test were evaluated by making use of the Gamma Rays Attenuation Technique (GRAT). The results show that GRAT is effective in determining sediment concentration distributions formed from non-Newtonian solutions, allowing the constitutive equations to obtain pressure and the solid porous medium permeability, very important for simulations of solid-liquid separation processes.