C.R. Duarte

• Federal University of Uberlândia

Brewer’s spent grain (BSG) is a residue that holds significant potential for various applications. Given its inherently high moisture levels, it becomes imperative to explore methods for preserving it. This study investigates the use of refractance window (RW) for drying BSG. The final moisture content, water activity, and drying kinetics were asse...

Rotating discs are usually used as granulators in many industrial processes. The efficiency of the granulation process in this device is directly related to the particle motion behavior in different flow regimes. In this work, the granular flow in a rotating disc was investigated experimentally and numerically. The Discrete Element Method (DEM) was...

Pharmaceutical, nutritional and food industries have recently become interested in the potential of Spirulina platensis, a kind of cyanobacterium with high levels of proteins, vitamins and bioactive compounds. Because of its high moisture, this microalga needs to be submitted to a preservation technique such as drying to be properly used. The aim o...

Even though the residue from the processing of acerola (Malpighia emarginata D.C.) has significant amounts of vitamin C and other bioactive compounds at the same level as the pulp and the juice of this fruit, it also has a high moisture content level (> 80%). In this work, the drying performance of acerola residue in a microwave oven combined with...

Although the rotating dishes are widely used in industrial processes, there are not many studies regarding the behavior of granular flow in this type of device. It is reported that the particle dynamics directly influences the dish performance in relation to its applications, e.g., in the granulation process. This work provides an experimental stud...

The DEM technique has been widely employed to study the mechanical behavior of granular systems in several engineering fields. However, this approach has some drawbacks, such as the need to specify the input parameters. This work aimed to measure experimentally the restitution coefficient (COR) of chrome steel balls and quartzite gravel by varying...

A systematic investigation concerning the particle mixing behavior in a flighted rotary drum through experiments and numerical simulations using DEM was performed in this study. The DEM input parameters were calibrated herein based on experimental observations. The effects of the number of flights, the height of the flights, and the drum filling de...

Even though the residue from the processing of acerola ( Malpighia emarginata D.C.) has significant amounts of vitamin C and other bioactive compounds at the same level as the pulp and the juice of this fruit, it also has a high moisture content level (> 80%). In this work, the drying performance of acerola residue in a microwave oven combined with...

Spouted beds have been extensively studied for various applications due to their cyclic solid motion and intimate gas-solid contact. However, there are some applications that need more vigorous contact and shorter residence time than those observed in conventional spouted beds, and in some cases a high accumulation of sticky materials can even caus...

The proper choice of the dryer configuration for seeds drying is essential to preserve their quality during this process. Drying of soybean seeds was studied in this work using a non-conventional configuration of rotary dryer, named as roto-aerated dryer. The effects of temperature and velocity of the drying air on drying performance and on the cap...

The performance of flighted rotary drums strongly depends on the distribution of the particles across the drum transverse and longitudinal sections. This work aims to determine the design and arrangement of flights that optimize the distribution of the particles in the active region. The prediction of the solids flow was investigated by DEM simulat...

Acerola is a tropical fruit whose residues from its processing contain amounts vitamin C, phenolic and other bioactive compounds at the same level of the fruit pulp and juice. In this work we used a novel system for acerola waste drying, which is composed by a new rotary dryer (developed by our research group), named roto-aerated dryer, equipped wi...

Biomass is a renewable energy source of increasing industrial interest. However, due to particle physical characteristics, operational problems are verified during its transport, which is usually associated with the control of the feeding process. In this context, a feeding system was designed, specifically for the control of biomass flow rate, in...

Predicting the flow behavior of particles is important for the equipment design and optimization of processes and operations involving granular materials. Simulations using the discrete element method (DEM) have been used to gain insights about the granular flow, but the correct use of this technique requires knowledge about the input parameters. H...

Camu-Camu (Myrciaria dubia) is a native fruit from the Amazon region, which is still little known by most people, but that has been arousing great interest from the scientific community due to its significant concentrations of important bioactive compounds. In this work, the drying of Camu-Camu pulp was investigated using an alternative system: a r...

This paper aims to systematically investigate the cataracting-centrifuging transition in a rotary drum involving spherical and nonspherical particles by using the Multiphase Granular Eulerian Model (MGEM). The effects of drum length and particle shape on the cataracting-centrifuging transition behavior were analyzed. The results showed that drum le...

The particle dynamics in a flighted rotary drum operated with different numbers of flights and under different operating conditions was simulated by using both the Eulerian (computational fluid dynamics, CFD) and the Lagrangian (discrete element method, DEM) approaches. The simulated solid holdups in the flights as a function of the flights’ tip an...

A low-cost and non-intrusive methodology using a solidification-slicing approach was proposed in this work for the investigation of radial and axial segregation phenomenon in a spouted bed. The effects of diameter, density, and shape of the particles, as well as the initial particle loading, and the inlet air velocity on segregation, were qualitati...

It is very well known that crude oil is extracted from the earth crust by drilling process and when the drill bit reaches the oil reservoir, the drill cuttings are being mixed with oil. The reservoir drill cuttings with oil are hazardous to the environment and cannot be disposed as such and an appropriate method is needed for disposal. To perform a...

The industrial processing of acerola generates a large amount of waste that is usually discarded or underutilized, causing losses of raw material and energy, as well as environmental impact. As these agro-industrial residues are rich in antioxidant compounds, they can be better used. In this work the drying of acerola residues in a novel device (ro...

Coffee drying and roasting are usually performed in rotated dryers; therefore, the study of particle dynamics in this equipment is of great relevance to improve their efficiency and hence the quality of the final product. Thus, this work aimed to investigate experimentally and numerically the dynamics of coffee beans in a rotary dryer. The Euler-Eu...

The aim of this work is investigate the use of a rotary dryer with inert bed for drying of microalga Spirulina platensis. The influence of air temperature, feed rate, rotation speed and inerts filling degree was quantified. The contents of main bioactive compounds were also analyzed. The results shown that the used drying system proved to be an int...

Acerola (Malpighia emarginata D.C.) is a tropical fruit which has attracted recent industrial interest, due to its high levels of bioactive compounds and vitamin C. However, acerola processing generates a substantial amount of wastes, which can represent up to 40% of total processed volume. The drying of acerola residues in a new dryer, developed b...

Although rotating dryers with flights have been extensively used in industrial applications, there is still a lack of universality in the literature models to estimate their design loading. The aim of the present paper was to study the design loading of a flighted rotating drum and its dependency on rotational speed. The use of high rotational spee...

Brazil is the largest producer and exporter of coffee in the world, one of the main global commodities. During the processing of coffee beans, rotary drums are used in the drying and roasting phases. This equipment is widely used in many industrial sectors. According to characteristics of the drum, particulate material, and operating conditions, di...

Drill cuttings generated by oil and gas drilling process are incorporated into the drilling fluid to ensure an efficient drilling and solids removal. The drilling rigs have a separation system accountable for separating drill cuttings and drilling fluids. Microwave drying is a new technology of separation that has been studied as an alternative to...

Rotary dryers are widely used in various industries. Although numerous research efforts have focused on characterizing the dynamics of these equipments, the design of rotating dryers is complex, and theoretical studies are necessary to gain an in-depth understanding of the dynamics of particles in these dryers. This paper aims to investigate the pa...

Tumbling ball mills are a common comminution device in the mineral industry processing, wherein the particle size reduction is performed by action of the grinding media. Different forms of transverse motion in a rotating cylinder have been studied by many researchers. The aim of this paper was to study the transitional phenomena between cascading,...

Dynamic of particles in annular fluid flow is a very relevant subject for many industrial applications, especially for the oil and gas industry. Successful drilling is, to a large extent, dependent upon the ability of the drilling fluid to clean the hole by conveying the cuttings to the surface. The aim of this work was to evaluate experimentally a...

This paper involves an experimental and numerical study on the grinding media dynamics inside a baffled ball mill under different solid flow regimes: cascading, cataracting and centrifuging. The Eulerian approach was used for all simulations and the boundary condition at the drum wall was investigated by means of the specularity coefficient paramet...

Background: The production and processing of fruits generate a large amount of residues, which are usually disposed of or underused, representing losses of raw material and energy. The present paper investigates the effect of four dehydration techniques (convective, infrared, microwave, and freeze-drying) on yellow passion fruit (Passiflora edulis...

The oil reservoir drilling phase generates contaminated cuttings with oil formation itself. These cuttings must be subjected to a decontamination process before being disposed of in the environment. Several technologies are cited in literature for the remediation of soil contaminated with oil or diesel, but none have been reported to remedy drill c...

This study presents an experimental and numerical investigation of the particle dynamic flow in a rotary drum with one flight, under different boundary conditions. The Euler-Euler approach with the kinetic theory of granular flow was used for all CFD simulations. The influence of different specularity coefficient values and no-slip boundary conditi...

Fruit production and processing result in a large amount of residues, which are usually discarded or underused. Passion fruit residues are source of fibers and other bioactive substances, which are antioxidant, protect cells against oxidative stress, and have pharmaceutical and food properties. This paper investigates the effects of freeze‐drying o...

This study presents a simulation and experimental study on the repose angle of acerola residues and soybeans as monoparticles and in binary mixtures. The simulations were performed using the Discrete Element Method. The contact forces among particles were represented using the Hertz-Mindlin and the JKR models. The effects of the main parameters of...

Rotary drums can show different granular flow regimes each one with its own specific flow behavior, which increase the complexity in their study. The way particles move inside the rotary drum is directly related to the mass and energy transfer rates, and consequently to the process performance. Thus, an experimental investigation regarding the tran...

In the solids control system, the removal of fine solids from drilling fluid is performed by decanter centrifuges. The use of these centrifuges is limited not only by the costs involved but also by the available space on the oil rig, so they cannot process the entire volume of fluid circulating in the drilling system. This paper proposes the use of...

The present paper describes an experimental and numerical study conducted to investigate the particle movement inside an unbaffled rotary drum under different operating conditions and using particles of different shapes. The Discrete Element Method (DEM) was used in order to describe the granular flow pattern properly, along with the clumping metho...

This paper quantitatively and qualitatively evaluates the mixture and segregation processes in an unbaffled rotary drum induced by particle size and density differences. We also assessed the initial particle loading effect using side–side and top–bottom particle configurations. The suitable segregation index and the segregation rate quantified the...

Residues of acerola generated as byproduct of fruit processing industry have been studied in this work, due to its potential use as food supplementation. To ensure proper processing, a detailed characterization of the acerola residues has been performed. The dehydration of these residues in a new dryer, named as roto-aerated dryer, has been investi...

This paper concerns an experimental and computational study of the laminar flow developed by a pseudoplastic fluid through a partially-obstructed annulus, considering the effects of eccentricity and inner cylinder rotation. For the eccentric cases the eccentric rotation of the inner tube is applied, which is a novelty in the literature. Pressure dr...

In directional drilling, the annulus is often eccentric and the eccentricity may vary along the well, due to the column weight and drilling conditions oscillations. Furthermore, by the gravitational effect, there will be a strong tendency for accumulation of solids at the lower part of the annulus, forming a settled cuttings bed that partially obst...

The drilling fluids most commonly used in oil and gas drilling operations are the non-aqueous drilling fluids. These fluids adhere to the drilled cuttings, and because of the Brazilian environmental legislation demands, they need to undergo a reduction on the organic phase content before disposal. Microwave drying has been investigated as a remedia...

Some types of drilling fluids commonly used in oil and gas drilling operations are highly toxic synthetic fluids with low biodegradability. These fluids contaminate drill cuttings, which must undergo decontamination before disposal. Microwave drying has been investigated as a remediation technique for drill cuttings. This work investigates the infl...

Directly heated rotary dryers are widely used in various industries and have been the subject of numerous studies. However, few studies have focused on the behavior of particle dynamics in these dryers, and most of them are still designed based on empirical data and pilot plant scale-ups. This paper reports on a study of the effect of operating con...

Mini-hydrocyclones are separators widely investigated with a view to expanding their applications in operations that require efficient separation of fine particles. The purpose of this study was to analyze the effects of design and operating variables, including the vortex finder length and height of the cylindrical body, cone frustum angle, underf...

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 th...

Rotary dryers are a significant capital item for many industrial plants. Many potential benefits can be obtained through a greater understanding of the rotary drying process. In order to improve drying efficacy, a novel version of the rotary dryer, known as the rotoaerated dryer, was evaluated in previous studies. This work has studied the effect o...

This paper aims to investigate the particle dynamic behavior in a rotating drum operating in a rolling regime under different rotating velocity, based on experimental results and simulations. Simple superphosphate fertilizer (SSP) was used as particulate matter in the current study. The Eulerian–Eulerian multiphase model along with the kinetic theo...

An experimental and numerical investigation of the hydrodynamic behavior in a rotating drum, operated in the rolling regime, was performed in the present work. For all the simulations, the Euler-Euler approach was used. A high-speed video camera technique was used in order to measure, experimentally, the particle velocity distribution. The CFD simu...

Some fluid-dynamics aspects of a rotary dryer, operating with granular single superphosphate, were investigated experimentally and by coupled discrete element model–computational fluid dynamics (DEM–CFD) simulations. The experimental data of flight holdup and dynamic angle of repose in the upper half flights, at different angular positions, were su...

In this work the particle dynamic behavior in a rotating drum under different operating conditions has been analyzed based on experimental results and simulations. The Eulerian–Eulerian multiphase model with the kinetic theory of granular flow was used in the simulations. In order to evaluate the simulation results, different solid flow regimes and...

Two different commercial hydrocyclones, Doxie® type-A and AKW® type RWK 21, were employed to separate yeast from alcoholic fermentation broth and their performances were compared. The independent variables selected for this study were the pressure at the inlet of both hydrocyclones, the pressure on the underflow of the Doxie hydrocyclone and the un...

AbstractA hybridisation study of drag models was performed in a conical–cylindrical spouted bed by means of CFD simulations using an Eulerian–Eulerian multiphase model. In order to evaluate the simulation results, time‐averaged velocity distributions of the particulate phase were compared with the experimental data obtained by means of an optical f...

West Indian cherry, widely known as acerola in Latin America, is a fruit rich in vitamin C and other bioactive compounds. In Brazil, the largest producer of acerola in the world, the processing of this fruit results in large amounts of waste or residues. A method that allows these residues to be reused is drying. However, acerola residue has low fl...

This work involved the use of a hydrocyclone to separate yeast from alcoholic fermentation suspensions. The performance of the hydrocyclone was quantified using empirical models that describe the capacity, total separation efficiency, flow ratio, and reduced separation efficiency as a function of the concentration of the suspension and the operatin...

A new geometry of liquid-liquid hydrocyclones is proposed seeking to perform the separation of oil emulsified in water. The hydrocyclone performance was investigated by means of a factorial experimental design (23) leading to a total of ten experiments. The results enabled the determination of empirical mathematical models that describe capacity, t...

Many spouted bed applications involve mixtures of particles of different sizes, shapes, or densities. Depending on the characteristics of the particle mixture, undesirable phenomena such as particle segregation may occur, mainly due to differences in terminal velocities. Thus, a better understanding of the fluid dynamics of particle mixtures is sti...

Conventional rotary dryers are used in many industrial sectors. The present work analyzes the drying of granulated fertilizers in a non-conventional dryer. The major characteristic of this new dryer is the presence of an aerated system consisting of a central pipe from which a series of mini-pipes conduct the hot air directly to the particle bed th...

Average particle velocity measurements were carried out in a conical-cylindrical spouted bed made of acrylic. In this study an intrusive fiber optical technique which is based on a cross-correlation function between signals from its two channels was used. For a non-intrusive measurement in order to compare with the intrusive technique, images of pa...

Hydrocyclones use the same principle of separation of centrifuges, but with no moving parts and no mechanical complexity. For these reasons as well as its versatility in applications, low cost, simple operation, small size, high production efficiencies with short residence times, these devices have been widely found in industry, and even suggested...

In the fermentation process of ethanol production, the yeast Saccharomyces cerevisiae is recovered and recycled to a new stage of fermentation. This separation process is a challenge because the yeast is small and low density. Thus, the hydrocyclone is an interesting alternative because it uses the same principle of centrifugal separation, requires...