Osvaldir Pereira Taranto

The drying of sewage sludge by immersion frying

The objective of this work was to dry sewage sludge using a fry-drying process. The frying experiments were carried out in commercial fryers modified by adding thermocouples to the setup. During frying, typical drying curves were obtained and it was verified that, in relation to the parameters: oil temperature, oil type and shape of the sample, the shape factor the most effect on the drying rate, at least within the range chosen for the variables studied. Oil uptake and calorific value were also analyzed. The calorific value of the samples increased with frying time, reaching values around 24MJ/kg after 600s of frying (comparable to biocombustibles such as wood and sugarcane bagasse). The process of immersion frying showed great potential for drying materials, especially sewage sludge, obtaining a product with a high energy content, thereby increasing its value as a combustible.

CONVECTIVE HEAT TRANSFER DURING COATING OF PARTICLES IN TWO-DIMENSIONAL SPOUTED BEDS

ABSTRACT This work deals with the evaluation of gas-to-particle convective heat transfer in a process of coating of particles in two-dimensional spouted beds. A detailed calculus routine is presented and two correlations of heat transfer coefficient, for the spout and annular regions are derived. The study is performed with two, two-dimensional spouted beds with different sizes and with two different particles, placebo and soybean.

Drying of a Porous Material in a Pulsed Fluid Bed Dryer: The Influences of Temperature, Frequency of Pulsation, and Air Flow Rate

In this work, a four-section pulsed fluid bed apparatus with a 0.18 m2 cross-section area was used to investigate the influence of pulsed-fluidization variables on the drying process of molecular sieves, a test material that was chosen because it presents an initial constant drying rate period. A two-level factorial design was developed to evaluate the influences of the inlet gas temperature—40 and 70°C—the frequency of pulsation—250 and 900 rpm—and the air flow rate—500 and 600 m3(STP)/h—on the drying rate. In addition, a comparison was made between the drying rates achieved with conventional and pulsed fluidization. Results showed that all the investigated variables affect the drying rate. Moreover, drying rates with conventional fluidization are considerably higher, which shows that one must expect a lower drying rate when pulsation is used in a drying process controlled by the external evaporation. Concerning fluid dynamics, this work also analyzed the influence of the frequency of pulsation on the pressure drop across the bed. The higher the frequency, the higher the pressure drop. That result can be explained by the reduction of channeling.

DRYING IN THE ROTATING-PULSED FLUIDIZED BED

There are particulate materials that are cohesive when wet. Although they are Geldarts group A dry powders, they show difficulties in fluidizing in a conventional fluidized bed, which could be diminished by modifying the fluidization equipment. Therefore, the objective of this work was to study the drying of cohesive particulate material using a rotating-pulsed fluidized bed. The material used in the drying study was 2-hydroxybenzoic acid because its cohesive forces are stronger when wet. The drying experiments were carried out according to the following parameters: frequency of disk (5 and 15 Hz), initial moisture content of the material (high and low) and gas temperature at 85°C. From the drying kinetic curves and visual observations during the experiments, it could be concluded that the rotating-pulsed fluidized bed is an alternative for the processing of cohesive solids that preserves the final quality of the dry solids.

The drying of solids in a modified fluidized bed

When fine and cohesive particles are the subject of study, fluid beds are of concern of due to the formation of channeling. This work presents a study that was carried out on the drying of fine particles, in this case a crystalline organic acid, in a mechanically stirred fluidized bed. The drying kinetics curves were determined by evaluating the influences of initial moisture content and temperature of the drying gas at the entrance of the bed. This study shows the suitability of the stirred fluidized bed for the drying of solids of low-quality fluidization.

Drying of Brazilian Pepper-Tree Fruits (Schinus terebinthifolius Raddi): Development of Classical Models and Artificial Neural Network Approach

In this study, the drying process of Brazilian pepper-tree fruits (Schinus terebinthifolius Raddi) was investigated, with emphasis on the development of models for the drying kinetics. A central composite rotable design (CCRD) with 11 experiments was carried out. In each experiment, the drying kinetics and the drying rate were observed. Classical models were fitted to the drying data, as well as a model based on Artificial Intelligence. The results revealed that the air temperature has the greatest influence on the process in the range of the experimental conditions. The modeling by artificial neural network and the Henderson model showed the most suitable results.In this study, the drying process of Brazilian pepper-tree fruits (Schinus terebinthifolius Raddi) was investigated, with emphasis on the development of models for the drying kinetics. A central composite rotable design (CCRD) with 11 experiments was carried out. In each experiment, the drying kinetics and the drying rate were observed. Classical models were fitted to the drying data, as well as a model based on Artificial Intelligence. The results revealed that the air temperature has the greatest influence on the process in the range of the experimental conditions. The modeling by artificial neural network and the Henderson model showed the most suitable results.

Real-Time Monitoring of Gas–Solid Fluidized-Bed Granulation and Coating Process: Evolution of Particle Size, Fluidization Regime Transitions, and Psychometric Parameters

Moisture content and particle size are critical parameters in fluidized-bed granulation and coating. In this study, microcrystalline cellulose was granulated and coated. The particle size was monitored in real time by a Parsum IPP70 probe. The fluidization regime was assessed by Gaussian spectral analysis. The bed temperature and gas humidity profile were monitored to evaluate the drying efficiency. The defluidization phase was detected in the early stages with frequencies below 6.0 Hz. The Parsum probe showed the growth of the particles due to agglomeration. The psychometric parameters indicated the lower potential energy for drying. Therefore, monitoring in real time is important to detect failures.

Identification of defluidization region in a gas-solid fluidized bed using a method based on pressure fluctuation measurements

Industrial applications that involve fluidized bed operations must prevent the undesirable phenomenon of partial or complete bed defluidization. Defluidization can be avoided by increasing the gas velocity and/or, in some cases, changing the solid feed conditions in the system, provided that the changes in the hydrodynamics of the flow are detected early enough. The use of a technique that can perform an early detection of the defluidization condition in industrial applications is important, in order to avoid the loss of efficiency or even an undesirable shutting down of the process. The objective of this work is to show the application of a method for early detection of the condition where the bed is tending to the defluidization, in a gas-solid fluidized bed flow. The method is based on pressure fluctuation measurements. Experimental tests are carried out using two solid particles: microcrystalline cellulose and sand. Results show that the proposed method is efficient in detecting the fluidization condition in a conventional bubbling bed regime. The potential of application of the technique is also shown for the control of the defluidization phenomenon in industry.

Application of Microfluidics in Process Intensification

Abstract Is it possible to miniaturize a chemical plant? Some strategies, such as the process intensification, sustain that the advancements in equipment and production techniques could substantially decrease the equipment size/production capacity ratio, energy consumption and waste generation, resulting in more economic and sustainable operations and consequently reducing the chemical plant size. However, large reductions of equipment volume represent a major challenge for the conventional technologies. In this context, Microfluidics represents a promising technology in the field of system miniaturization. Accordingly, the present research evaluated the concept of process intensification and its relationship with Microfluidics. Initially, the definition and the classification of process intensification were described, following by the explanation of the Microfluidics, highlighting scale-up strategies and examples using miniaturized systems. Afterward, a methodology for miniaturized devices development for process intensification using numerical simulations was shown. Finally, the conclusions are exposed.

Optimization of hydrodistillation and in vitro anticancer activity of essential oil from Schinus terebinthifolius Raddi fruits

Abstract Although several studies show that Schinus terebinthifolius Raddi fruits are a promising source of bioactive compounds, few studies have investigated the anticancer activity of its essential oil (EO). The objective of this study was therefore to investigate the antiproliferative activity of S. terebinthifolius fruit EO against eight human tumor cell lines. A central composite rotatable design with 11 experiments was developed to investigate the optimal conditions of hydrodistillation by Clevenger apparatus. EO obtained at optimized conditions (yield greater than 6.7%) showed potent activity for all cell lines investigated; the most promising results were observed against leukemia, kidney, multidrug-resistant ovarian, and prostate tumor cell lines. Gas chromatography-mass spectrometry revealed the following major compounds in the EO: δ-3-carene (33.78–36.73%), α-phellandrene (15.67–17.30%), limonene (15.03–16.32%), α-pinene (7.03–9.20%), and germacrene D (4.98–6.99%). Future work involving fractionation of the EO might shed some light on the compounds responsible for each antiproliferative activity.