Influence Collector Inclination of Solar Dryer on Apple ‘Golab’ Chips Drying

Thin layer of apple chips (‘Golab’) with 73.4% (wet basis) moisture content were dried in a hybrid solar dryer. A new mechanism was designed to change inclination of the collector. Drying experiments were run in three levels of airflow rates and two levels of collector tilted angle. In order to describe the thin layer drying, ten different models were selected. The goodness of fitting was evaluated by calculating and comparing the statistical values for each model. The approximation of diffusion and the Midilli model were chosen for 30, and 45 degrees of tilted angle, respectively. Besides, five linear and nonlinear equations were derived in order to establish the best relationship for every empirical coefficient with temperature and airflow rate. Results revealed that the 2nd polynomial equations were suitable to predict these coefficients. Comparison between moisture ratio data in different inclination evidenced that more drying intensity occurred with 30 degrees of slope angle and airflow 0.018 m3・s-1

Design and Construction of a Cabinet Dryer for Food Waste and Evaluation of its Kinetics and Energy Consumption

IntroductionProviding new solutions to control wet waste is one of the most important issues in maintaining public health. Drying will reduce the harmful effects on the environment by reducing moisture and the smell of wastes as well as easy transportation and disposal costs. The purpose of the design and development of the household dryer is to dry food waste in order to reduce its volume and prevent the spread of its pollution in the air, water, and soil. To study the drying behavior of food waste, an experimental cabinet dryer was designed, fabricated, and evaluated for drying food waste.Materials and MethodsThe dryer consisted mainly of the drying chamber, electric heater, fan, air inlet channel, mesh tray, air distribution plates, temperature sensor, and control panel. Different parts of the dryer were made of a stainless galvanized sheet. The dryer was modeled using Catia 2019 software and its various parts were designed. The heating power was calculated as 2.7 kW. A centrifugal fan with an air volume of 310 m3h-1, 2800 rpm, and 110 Pa was used to supply airflow in the dryer. In the drying process, a tray with medium and lateral air passage was fabricated and applied. Food waste was obtained from fruit and vegetable waste, homemade food, and fruit shops. And nonfood items such as glass, paper, plastics, and metals were separated from the waste and crushed with a shredder, and reduced to sizes less than 20 mm. First, the product was placed in the environment for one hour and then pressed with a mechanical press with the same pressure to eliminate part of the water. An anemometer UT363 model made in China was used to measure the air velocity. The temperature was measured and controlled by a temperature thermostat of G-sense model made in Iran. The effect of three temperatures of 50, 60, and 70 °C and three inlet velocities of 1, 1.5, and 2 m s-1 on the kinetics and intensity of drying of food waste and energy consumption of food waste with a thickness of 3 cm was investigated. Moisture ratio and drying intensity diagrams were extracted. Diffusion, activation energy, and energy consumption were determined.Results and DiscussionDrying kinetics diagrams showed that temperature had a significant effect on moisture variation of food waste during drying. Drying period decreased with increasing temperature. The slope of the drying intensity diagrams increased with the increase of the dryer temperature. Drying rate was decreased at the temperature of 70 °c and it had a steeper slope that indicates the more intensity of the drying process in this condition. The drying process of all three samples occurred in the falling rate stage. The air duct on the side and in the middle of the tray caused hot air conducted above the tray and increased energy consumption. Effective moisture diffusivity of food waste during the drying process was in the range of 3.65×10-9-4.56×10-9 (m2 s-1). The effective moisture diffusivity at temperatures of 50 °C and 60 °C was less than 70 °C. Because at the temperature of 70 °C, the membrane resistance of the cell destroyed by high heat and increased the diffusion coefficient in the material.ConclusionIncreasing temperature caused the drying period decreased and the drying occurred in the falling rate stage. Temperature and the interaction of velocity and temperature had a significant effect on the drying process. The highest drying intensity and the lowest drying time were observed at the temperature of 70 °C and a velocity of 2 m s-1. Energy consumption had the maximum value at the temperature of 70 °C and a velocity of 2 m s-1 and a minimum value at the temperature of 50 °C and a velocity of 1 ms-1. The amount of activation energy for the food waste mass at three velocities was equal to 10417.44 J mol-1

Optimization of spray-drying conditions for lulo (Solanum quitoense L.) pulp

The spray drying of lulo was optimized by using the central composite design of the response surface methodology, to study the effect of inlet air temperature (120-180 degrees C), arabic gum concentration (0-10% w/w), and maltodextrin DE16.5-19.5 concentration (0-10% w/w) on some product and process aspects. Arabic gum and maltodextrin, more than inlet air temperature, improved the product yield, reduced the hygroscopicity and the water content of the obtained powder, and contributed to the retention of its nutritive and functional properties through an increase in ascorbic acid, vitamin C, total phenol and total flavonoid content and antioxidant capacity. Significant (p < 0.05) response surface models were obtained in every case, with the linear terms of solute concentration being the factors that affected the response variables most significantly. The overall optimum spray drying conditions for obtaining lulo powder were 125 degrees C inlet air temperature, 3% (w/w) arabic gum, and 13.4% (w/w) maltodextrin DE16.5-19.5. (C) 2014 Elsevier B.V. All rights reserved.The authors thank the Universidad Politecnica de Valencia for the financial support given throughout the Project ADSIDEO-COOPERACION 2010 "Adaptacion de procesos de secado para favorecer la comercializacion de super frutas de origen colombiano".Igual Ramo, M.; Ramires, S.; Mosquera, LH.; Martínez Navarrete, N. (2014). Optimization of spray-drying conditions for lulo (Solanum quitoense L.) pulp. Powder Technology. 256:233-238. doi:10.1016/j.powtec.2014.02.003S23323825

Evaluation of Mechanical Z-Type Elevator Operation for Handling Seed Corn

Handling systems in seed processing factories inflict impressive damages on seed corn. It was reported 24% of damages on seed corns related to elevators. In current research, the operation of a Z- Shape elevator was studied and compared to conventional bucket elevator which employed in two seed drying stations of Seed and Plant Improvement Institute in Karaj city and Shahi plant in Moghan plain, Iran. The effect of elevator operation on seed cracking and breakage was determined by t- test. According to the results, applying Z- Shape elevator decreased the physical seed damages up to 78% and reduced the chance of seed cracking between 4 to 8% in comparison with conventional elevators. Economically results illustrated spending the cost equal to 10% of the loss funds which was accrued due to employing conventional elevators, could decrease damages until 90% in Moghan plain

Influence of Temperature and Total Soluble Solids on Thermo-Physical Properties of Pomegranate Juice

Determination of thermo-physical properties of pomegranate (Punica granatum L.) juice is essential for examining, controlling, and developing numerical models of processes such as drying and concentrating. These properties are affected by changing the percentage of soluble solid content (oBrix) and temperature. Thermophysical properties of pomegranate juice including density, specific heat and thermal conductivity at temperature range from 25 to 70oC and at the three levels of soluble solid content (12, 40 and 65 oBrix) were investigated in this research. Thermal conductivity, density, and specific heat were measured by co-axial cylinder, volumetric pycnometer and differential scanning calorimeter (DSC), respectively. Results from regression analysis of output data showed that both temperature and solid content affected the thermo-physical properties of pomegranate juice; however, the soluble solid content exhibited a greater effect. By increasing soluble solid content and decreasing temperature, thermals conductivity and specific heat have been reduced linearly but density increased during augment of soluble solid content or decrease of temperature

Numerical Simulation of Conventional and Porch Patterns for Air Inlet Channel in Paddy Dryer

Introduction Long drying time and high energy consumption are the big problems in paddy drying using conventional batch type dryer. Besides, non-uniformity occurs in paddy rice dried and low milling quality. Paddy is over dried in lower layers and broken kernel chance increased in milling process. Using of a new pattern for warm air causes to better air passing through the paddy bulk and uniformity of drying. Computational fluid dynamics (CFD) is a good method for modeling of air passing in dryers in order to find better air condition in paddy drying process. The aim of this research was investigation on common and porch patterns applied for air entrance to paddy bulk in a dryer in order to optimize air channel conditions in a conventional paddy dryer. Materials and Methods In this study, optimization of air flow was investigated in a batch type paddy dryer using computational fluid dynamics (CFD). Two patterns as conventional and porch (reverse V type) patterns were applied for air entrance to paddy bulk in the dryer as conventional and porch (reverse V type) patterns. Experimental examination were done using a laboratory batch type dryer with chargeable air flow pattern in 50 °C for drying paddy (Tarom-Hashmei Var.). Numerical simulation of air velocity and pressure drop in porous media of paddy in the dryer was achieved by employing computational fluid dynamics method and Fluent software. Air velocity pattern and temperature changes in bulk of paddy were investigated in different time of solution including 20, 100, 1000, 1800, 3600 and 7200 seconds for both patterns. Results and Discussion Considering air flow and temperature as constant, the results showed the porch type pattern has better performance than the conventional pattern for air passing in the dryer. The velocity vortex was higher in all parts of the channel in the porch scheme. Air velocity uniformed decreased from beginning to end area in the conventional pattern, but in the porch type pattern, air velocity was more in the end of the duct than beginning area. Pressure drop was about 10 percent in the conventional pattern than porch pattern. At the end of the air channel, this variation inversed due to contact of the air with the end wall and pressure drop in this part of the chamber of porch scheme was higher than the conventional one. Improvement of air flow in paddy occurred in low and middle layers in the porch type pattern and there was no difference between two air passing patterns in top layers. Validation of modeling showed that temperature disturbance of the porch model was more uniform than the conventional model and difference between temperatures of model and experiments was about 2 to 3 °C. Conclusions The research concluded that using of the porch type pattern had better performance than the conventional pattern for air passing in the dryer but it is needs to more supplementary research to find the best height and angle in the paddy dryer. Porch type pattern causes to more speed and uniformity of air among of paddy than the conventional pattern. This improvement observed in low and middle layers of the paddy bulk. Validation of temperature data showed that the difference between experimental and modeled data was 4 to 6 percent and this difference was higher in the conventional pattern than the porch pattern. According to the results of this research, Porch pattern can be recommended to use in the conventional batch type dryer