Simulation and Design Optimization of a Tall-Form Spray Dryer

Author(s):  
Joanna Tess Masilungan-Manuel ◽  
Allan N. Soriano ◽  
Mark Christian E. Manuel ◽  
Po Ting Lin

Airflow stability plays a vital role in optimizing the spray dryer operation; wherein the airflow patterns present inside the drying chamber are considered as the primary factors that influences the histories of the product particle. In this paper, the optimum drying parameters that would produce a higher yield of powdered egg while retaining its quality parameter such as moisture content and water activity were determined by means of Euler-Lagrange Discrete Phase Modeling (DPM) numerical method present in the ANSYS-Fluent ver. 14.5 CFD solver. During the computational simulation, the flow pattern of the air was first identified using the Eulerian method then the results were coupled using the Lagrangian-Discrete Phase Modeling to track the particle histories of the disperse phase inside the tall-form spray drying chamber. Results showed that the optimum inlet air velocity and temperature are 8.87 m/s and 444 K respectively. At these conditions, the particle trajectories simulated exhibited that the calculated final moisture content and water activity for the dried egg powder are 1.09 % and 0.012, respectively.

Author(s):  
Ahmed Hossam El-Din ◽  
Aya Diab

The process of surface erosion due to particle collision has been the focus of a number of investigations with regards to gas turbine engines, aircraft, reentry missiles, pipelines carrying coal slurry, etc. Recently, increased interest in wind energy by countries in the Saharan regions of the Middle East and North Africa (MENA) brings about some concern about leading edge erosion of wind turbines operating under such dusty conditions. Leading edge erosion can have a detrimental impact on the extracted energy as it changes the blade surface roughness causing premature/unpredictable separation. Though erosion may not be easily avoided; it may be mitigated via using airfoil families characterized by low roughness sensitivity. In this paper, a model of an airfoil erosion subjected to sand blasting is developed using the discrete phase modeling capability in ANSYS-FLUENT along with the DNV erosion model. The effect of various flow parameters, such as angle of attack, and particle size, on the extent of erosion is investigated for a number of airfoil designs. The developed model is used as a predictive tool to assess the power deterioration of eroded wind blades.


2017 ◽  
Vol 13 (10) ◽  
Author(s):  
Sidrah Ashfaq ◽  
Manzoor Ahmad ◽  
Anjum Munir ◽  
Abdul Ghafoor

AbstractAir heterogeneity in the drying chamber of the batch-type dryer is a major problem because uneven air distribution within the drying chamber reduces the product quality and dryer efficiency. To surmount this problem, a new dryer with central air distribution model has been designed and developed. This is the distinct design feature of the dryer, which ensure the uniformity in the moisture content of the final dried paddy grains. ANSYS-Fluent (Computational Fluid Dynamics [CFD]) was used to predict the flow behavior of the air with respect to pressure and velocity within the drying chamber by applying actual boundary conditions and standardk−εturbulence model. Pressure and velocity profiles in the drying chamber were determined using CFD to optimize the drying uniformity. An estimated value for velocity input was used and air distribution was found good. For the validation of simulation results several drying tests were performed at different dryer depths of 18, 36, 54 and 72 cm in the drying chamber. The drying results expressed as percentage moisture content reduction, along the length of the dryer and measured the uniformity in the drying rate. The drying curves for each depth showed highR2value. Numerical simulation and experimental results showed that the newly developed solar-assisted paddy dryer is capable to produce uniform air distribution throughout the length of the drying chamber in the dryer for uniform and quality drying. This approach improved the overall performance of the solar-assisted paddy dryer.


Foods ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 5
Author(s):  
Paola Littardi ◽  
Massimiliano Rinaldi ◽  
Maria Grimaldi ◽  
Antonella Cavazza ◽  
Emma Chiavaro

Green coffee parchment (GCP) is becoming interesting, due to the diffusion of wet processing in which coffee parchment is collected separately; it is one of the less studied coffee by-products, but it is reported to be rich in phenolic compounds and dietary fiber. The addition of GCP (355–500 μm) at 2 % to gluten-free breads was investigated in terms of physical properties (volume, moisture content, water activity, crumb grain, texture, and color), total antioxidant capacity (TAC) and total phenol content during three days of storage. Moreover, the effects of GCP on sensorial characteristics, 5-hydroxymethylfurfural (HMF), and oxidative stability was evaluated. From the sensorial analysis, bread with 2% addition resulted in being acceptable for consumers with no significant differences from the control, while 4% of GCP was discarded by consumers, as it resulted in being too bitter. Moreover, GCP at 2% addition did not modify volume, moisture content, and water activity. On the contrary, GCP deeply affected the color with a darker aspect that was appreciated by consumers. Regarding texture, 2% of GCP did not affect hardness, cohesiveness, and staling process during storage. Interestingly, 2% of GCP significantly improved the TAC and oxidative stability of the bread; in accordance with these results, 2% of GCP reduced the HMF content, thanks to its antioxidant compounds.


2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.


2005 ◽  
Author(s):  
P. M. Mohan Das ◽  
R. S. Amano ◽  
T. Roy ◽  
J. Jatkar

Heated Soil Vapor Extraction (HSVE), developed by Advanced Remedial Technology is a Soil remediation process that has gained significant attention during the past few years. HSVE along with Air sparging has been found to be an effective way of remediating soil of various pollutants including solvents, fuels and Para-nuclear aromatics. The combined system consists of a heater/boiler that pumps and circulates hot oil through heating wells, a blower that helps to suck the contaminants out through the extraction well, and air sparging wells that extend down to the saturated region in the soil. Both the heating wells and extraction wells are installed vertically in the saturated region in contaminated soil and is welded at the bottom and capped at the top. The heat source heats the soil and the heat is transported inside the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then absorbed by the extraction well. Soil vapor extraction cannot remove contaminants in the saturated zone of the soil that lies below the water table. In that case air sparging may be used. In air sparging system, air is pumped into the saturated zone to help flush the contaminants up into the unsaturated zone where the contaminants are removed by SVE well. In this analysis an attempt has been made to predict the behavior of different chemicals in the unsaturated and saturated regions of the soil. This analysis uses the species transport and discrete phase modeling to predict the behavior of different chemicals when it is heated and absorbed by the extraction well. Such an analysis will be helpful in predicting the parameters like the distance between the heating and extraction wells, the temperature to be maintained at the heating well and the time required for removing the contaminants from the soil.


Author(s):  
MILTON CANO-CHAUCA ◽  
AFONSO M. RAMOS ◽  
PAULO C. STRINGHETA ◽  
JOSÉ ANTONIO MARQUES ◽  
POLLYANNA IBRAHIM SILVA

Curvas de secagem de banana passa foram determinadas, utilizando-se três temperaturas do ar de secagem. Os resultados indicaram que para reduzir o teor de umidade do produto até 23,5% foram necessários tempos de secagem de 51, 36 e 30 horas paras as temperaturas de 50, 60 e 70ºC, respectivamente. O modelo exponencial U/Uo = exp(-kt) foi ajustado para os dados experimentais mediante análise de regressão não-linear, encontrandose alto coeficiente de regressão linear. Determinou-se a atividade de água do produto ao longo do processo de secagem para as três temperaturas testadas. Estudou-se a correlação entre a atividade de água e o teor de umidade do produto, determinando-se as isotermas de dessorção da banana passa a 25ºC. Observou-se que a atividade de água diminuiu em função do tempo de secagem e do teor de umidade para as três temperaturas de secagem. Os dados experimentais foram ajustados mediante regressão não-linear ao modelo polinomial e a seguinte equação foi obtida: U = -1844,93 + 7293,53Aa – 9515,52Aa2 + 4157,196Aa3. O ajuste mostrou-se satisfatório (R2 > 0,90). DRYING CURVES AND WATER ACTIVITY EVALUATION OF THE BANANA-PASSES Abstract Banana drying curves were determined by utilizing three drying air temperatures. The results indicated that to reduce the moisture content of the product until 23.5% it were necessary drying times of 51, 36 and 30 hours for temperatures of 50, 60 and 70ºC, respectively. The exponential model U/Uo = exp(-kt) was adjusted for the experimental data by means of non linear regression analysis, and a high coefficient of linear regression was found. The water activity of the product was determined throughout the drying process for the three tested temperatures. The correlation between the water activity and moisture content of the product was studied, and the sorption isotherms were determined at 25º C. It was observed that the water activity decreased in function to the drying time and moisture content for the three drying temperatures. The experimental data were adjusted by means of non linear regression to the polynomial model and the following equation was obtained: U = - 1844.93 + 7293.53A a – 9515.52 Aa 2 + 4157.196A a 3. The final adjust was satisfactory (R2 > 0.90).


2013 ◽  
Vol 393 ◽  
pp. 839-844 ◽  
Author(s):  
Mohamad Shukri Zakaria ◽  
Kahar Osman ◽  
Mohd Noor Asril Saadun ◽  
Muhammad Zaidan Abdul Manaf ◽  
Mohd Hafidzal Mohd Hanafi

Research on the waste energy and emission has been quite intensive recently. The formation, venting and flared the Boil-off gas (BOG) considered as one of the contribution to the Greenhouse Gas (GHG) emission nowadays. The current model or method appearing in the literature is unable to analyze the real behavior of the vapor inside Liquefied Natural Gas (LNG) tank and unable to accurately estimate the amount of boil-off gas formation. In this paper, evaporation model is used to estimate LNG Boil-Off rate (BOR) inside LNG tank. Using User Define Function (UDF) hooked to the software ANSYS Fluent. The application enable drag law and alternative heat transfer coefficient to be included. Three dimensional membrane type LNG cargos are simulated with selected boundary condition located in the United States Gulf Coast based on average weather conditions. The result shows that the value of BOR agrees well with the previous study done with another model and with International Marine organization (IMO) standard which is less than 0.15% weight per day. The results also enable us to visualize the LNG evaporation behaviors inside LNG tanks.


Author(s):  
Fernando M. Botelho ◽  
Nilso J. Boschiroli Neto ◽  
Silvia de C. C. Botelho ◽  
Gabriel H. H. de Oliveira ◽  
Michele R. Hauth

ABSTRACT Knowledge of the water sorption phenomenon in Brazil nut seeds will allow proper handling of this product, especially with regard to adequate conditions for safe storage. Thus, the present study aimed to determine the sorption isotherms (desorption and adsorption) of Brazil nuts, fitting different mathematical models to the experimental data, as well as to examine the hysteresis effect. To obtain the sorption isotherms, the static method was employed at temperatures of 25, 35, 45 and 55 °C and air relative humidities varying from 10 to 80%. The psychrometric conditions of the air were acquired with the aid of acid solutions and specific saturated saline left inside desiccators with the samples. It was verified that for a given isotherm, the equilibrium moisture content of Brazil nuts increases with water activity increment. In addition, at a constant water activity, equilibrium moisture content decreases with temperature increase. The Copace, Henderson and Oswin are the models that best describe the hygroscopicity of the Brazil nut seed for both the adsorption and desorption processes. Hysteresis was more pronounced at lower temperatures and higher values of water activity. The moisture content value for storage at temperatures less than 55 °C, without the risk of fungal development, must be lower than 8.2% (d.b.).


2018 ◽  
Vol 7 (3) ◽  
pp. 144-149
Author(s):  
Ismiyati Ismiyati ◽  
Fatma Sari ◽  
Ratri Ariatmi Nugrahani ◽  
Anwar Ilmar Ramadhan

As people today are becoming more health-conscious, various efforts have been made to keep up one’s health, such as by consuming highly nutritious food and drinks. One of the nutritious food sources produced from bees is honey, bioactive compounds of polyphenols, glyoxal and methylglioxal. Honey could be used as a health drink by mixing with ginger. This health drink is also produced as powdered drink to simplify storing, reduce the use of plastic packaging, and to add product value to increase market share. The aim of this research was to analyze the effects of drying time for 5, 15, and 25 minutes with an addition of maltodextrin on the yield, density, and moisture content of “Sumahe” instant powdered drink, made from cow’s milk, honey, and ginger. The results showed that the longer the drying time, the lower the moisture content of the drink. Meanwhile, the longer the drying time, the higher the yield became. A taste test of “Sumahe” also indicated that from 25 minutes of drying time, most of the panelists rated the drink as tasteful and delicious.


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