scholarly journals Indirect Convective Solar Drying Process of Pineapples as Part of Circular Economy Strategy

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2841 ◽  
Author(s):  
Yaovi Ouézou Azouma ◽  
Lynn Drigalski ◽  
Zdeněk Jegla ◽  
Marcus Reppich ◽  
Vojtěch Turek ◽  
...  
Keyword(s):  
Developing Countries ◽  
Circular Economy ◽  
Biogas Production ◽  
Convective Drying ◽  
Slice Thickness ◽  
Solar Drying ◽  
Drying Process ◽  
Statistical Design Of Experiments ◽  
Drying Time ◽  
Solar Radiation Intensity

This study investigates the industrial-scale application of a simple convective solar drying process of pineapples as part of a circular economy strategy for developing countries. A renewable energy concept is presented, which follows the circular economy aims by effectively employing a simple system for biogas production and a two-stage drying system. Both these systems meet the requirements for implementation in the specific conditions of developing countries, of which Togo, where pineapple is a major crop, is taken as an example. With respect to earlier findings available in the literature, the paper focuses on the solar drying process, which is critical to the proposed strategy. A portable solar dryer working in indirect heating mode was built and later also modified to enhance its performance. Three main factors influencing the convective drying process, namely, drying time (270 min, 480 min), solar radiation intensity (650 W/m2, 1100 W/m2), and slice thickness (6–8 mm, 12–14 mm), were considered. The statistical Design of Experiments (DOE) method was applied to reduce the number and scope of experiments. In the best case, the moisture content was reduced from 87.3 wt % in fresh samples to 29.4 wt % in dried samples, which did not meet the quality requirements for dried fruit. An additional conventional post-solar drying procedure would, therefore, still be necessary. Nonetheless, the results show that in the case of pineapple drying the consumption of fossil fuels can be decreased significantly if convective solar pre-drying is employed.

Modeling of Thin Layer Drying of Banana (Nendran Spp) under Microwave, Convective and Combined Microwave-Convective Processes

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Magesh Ganesapillai ◽  
I. Regupathi ◽  
Thanapalan Murugesan
Keyword(s):  
Thin Layer ◽  
Microwave Drying ◽  
Convective Drying ◽  
Mean Bias Error ◽  
Bias Error ◽  
Slice Thickness ◽  
Drying Process ◽  
Chi Square ◽  
Drying Time ◽  
Thin Layer Drying

Drying kinetics of microwave, convective and microwave assisted convective drying of thin layer Nendran banana was investigated on a modified microwave oven. The drying characteristics through the operating parameters of the drying process, such as power output, air temperature, slice thickness and sample mass in terms of drying rate equation, were analyzed. An appropriate empirical model to represent the drying process was established by analyzing the available literature models with current experimental data. The statistical analysis for the selected model was performed, parameters like Mean Bias Error, Root Mean Square Error, reduced chi square and t-stat were estimated to examine the consistency of the model to represent the present experimental results. Higher rates and shorter drying times were achieved at a higher temperature and microwave heating power and lesser sample thickness and load. Microwave drying resulted in a substantial decrease in the drying time with better quality product when dried at higher power (300 W) level compared to other processes.

scholarly journals BIOFUELS DRYING PROCESS EFFICIENCY RESEARCH / BIOKURO DŽIOVINIMO PROCESO EFEKTYVUMO TYRIMAI

2013 ◽  
Vol 5 (6) ◽  
pp. 609-614
Author(s):  
Osvaldas Šlepikas ◽  
Audrius Čereška
Keyword(s):  
Positive Impact ◽  
Ultrasonic Transducer ◽  
Process Efficiency ◽  
Convective Drying ◽  
Drying Process ◽  
Wood Pellets ◽  
Drying Time ◽  
Hot Air ◽  
Special Stand ◽  
Experimental Rig

The paper deals with biofuel drying process efficiency opportunities.Research was carried out with a special stand and performingexperiments. Experimental rig consists of an ultrasonic generator,ultrasonic transducer, a drying chamber and the humidity,temperature gauge. Tests were used for wood pellets. During theexperiment, they were irrigated with water, dried with hot air andadditionally exposed to different frequency ultrasonic vibrations.The tests results have showed that the convective drying processis combined with the ultrasonic vibrations, the drying time isreduced, which means a positive impact on the ultrasonic process.Studies have confirmed that the effectiveness of convectivedrying method combined with operating ultrasonic vibrationsincreases. Santrauka Straipsnyje nagrinėjamos biokuro džiovinimo proceso efektyvumo didinimo galimybės. Tyrimams atlikti sukurtas specialus stendas ir sudaryta eksperimento atlikimo metodika. Eksperimentinį stendą sudaro ultragarsinis generatorius, ultragarsinis keitiklis, džiovinimo kamera ir drėgmės, temperatūros matuokliai. Buvo tiriamos medžio granulės. Eksperimento metu jos buvo drėkinamos vandeniu, džiovinamos karštu oru ir papildomai veikiamos skirtingo dažnio ultragarsiniais virpesiais. Atlikus bandymus, rezultatai parodė, kad, veikiant konvekcinio džiovinimo procesą ultragarsiniais virpesiais, džiovinimo laikas sutrumpėja. Tai reiškia teigiamą ultragarso poveikį procesui. Tyrimais patvirtintas konvekcinio džiovinimo metodo efektyvumo, papildomai veikiant ultragarsiniais virpesiais, padidėjimas.

scholarly journals Investigation of Solar Drying of Ginger (Zingiber officinale): Emprical Modelling, Drying Characteristics, and Quality Study

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
A. Waheed Deshmukh ◽  
Mahesh N. Varma ◽  
Chang Kyoo Yoo ◽  
Kailas L. Wasewar
Keyword(s):  
Energy Requirement ◽  
Initial Moisture Content ◽  
Food Preservation ◽  
Convective Drying ◽  
Drying Methods ◽  
Solar Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Solar Dryer ◽  
Thin Layer Drying

Drying is a simultaneous heat and mass transfer energy intensive operation, widely used as a food preservation technique. In view of improper postharvest methods, energy constraint, and environmental impact of conventional drying methods, solar drying could be a practical, economical, and environmentally reliable alternative. In the present paper applicability of mixed mode solar cabinet dryer was investigated for drying of commercially important and export oriented ginger. Freshly harvested ginger slices were successfully dried from initial moisture content of 621.50 to 12.19% (d.b.) and their drying characteristics, quality parameters, and kinetics were evaluated. The results showed that present solar dryer could be successfully applied for drying of ginger in view of quality, reduced drying time, and zero energy requirement as compared to conventional open sun drying and convective drying techniques, respectively. Drying curves showed that drying occurred in falling rate period and no constant period was observed. The effective moisture diffusivity was determined by using Fick’s second law and found to be 1.789×10-9 m2/s. The drying data was fitted to five thin layer drying models and compared using statistical criteria. Page model was found to be most suitable to describe the drying kinetics of ginger in solar dryer under natural convection among the tested models.

scholarly journals Pulsed electric field pre-treatment efficiency analysis in processes of biomaterials drying

2019 ◽  
Vol 80 (4) ◽  
pp. 49-54 ◽  
Author(s):  
I. A. Shorstkii ◽  
D. A. Khudyakov
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Mathematical Models ◽  
Electric Field Strength ◽  
Pulsed Electric Field ◽  
Convective Drying ◽  
Efficient Production ◽  
Drying Process ◽  
Drying Time ◽  
Pre Treatment

The transition to an efficient economy and efficient production requires building the foundations for the development of energy efficient technologies and the drying of biomaterials to convert them into useful products. The purpose of this work is to analyze the effectiveness of pretreatment with a pulsed electric field (PEF) in the process of convective drying of biomaterials. The PEF was processed with electric field strength of 2, 4 and 6 kV/cm, the number of pulses 500, with a pulse duration of 50 ?s. Based on the electrical conductivity data of the biomaterial, the index of the disintegration 56% was determined before and after the PEF treatment, which confirms the existence of an electroporation mechanism of the material structure. The drying process is presented with a description of various mathematical models. PEF pre-treatment with the parameters of electric field strength 4 and 6 kV / cm and the number of impulses 500 allowed to reduce the drying time by 13.8% for the value E = 0.02. Total time spent on the drying process reduced by 20-25 minutes. It should be noted that the total energy spent on PEF pre-treatment (<150 W / kg) compared with the energy spent on the drying process is incommensurably small. Statistical analysis of the considered mathematical models showed good convergence of most models with experimental data. The considered technology of pretreatment of PEF can ensure the effective processing of biomaterials in the required amount to obtain high-quality and safe products. Obtained data of the kinetics process can be used to the mathematical model of the drying process design with the use of preliminary treatment processing.

scholarly journals РАЗРАБОТКА И ИСПЫТАНИЕ СОЛНЕЧНОЙ УСТАНОВКИ С ПОЛИКАРБОНАТНЫМ ПОКРЫТИЕМ ДЛЯ СУШКИ ПРОДУКТОВ СЕЛЬСКОГО ХОЗЯЙСТВА

World Science ◽  
2021 ◽  
Author(s):  
Ketevan Archvadze ◽  
Ilia Chachava ◽  
Ketevan Papava ◽  
Nanuli Khotenashvili ◽  
Riva Liparteliani ◽  
...  
Keyword(s):  
Vitamin C ◽  
Air Temperature ◽  
Laboratory Analysis ◽  
Agricultural Products ◽  
Solar Drying ◽  
Drying Process ◽  
Drying Time ◽  
Drying System ◽  
Natural Drying

The proposed solar drying system significantly reduces the drying time and improves the quality of the product, including the preservation of vitamins. When drying rosehip, a laboratory analysis for vitamin "C" showed that 28% of this vitamin is destroyed during natural drying, and 17% when using a solar dryer.The drying speed increases by 2.5 - 4 times compared to traditional outdoor drying.In the proposed installation, you can dry different agricultural products, you can change the coating of the solar drying unit. In S/D, the air temperature is higher than in the environment from about 13 to 32 degrees Celsius, depending on weather conditions.The drying process in the S/D apparatus allows you to ensure the purity of the products. S/D is covered and during the drying process the product is not contaminated with dust and rain, by influence of dew, is not damaged by birds, insects or wasps.This device is convenient for transportation, during the day it can be moved and rotated to align to the sun.The proposed solar dryer is easy to manufacture and can be widely used in large and small farms, private and subsidiary farms.

scholarly journals Kinetic parameters identification of conductive enhanced hot air drying process of food waste

2020 ◽  
pp. 223-223
Author(s):  
Mihailo Milanovic ◽  
Mirko Komatina ◽  
Ivan Zlatanovic ◽  
Nebojsa Manic ◽  
Dragi Antonijevic
Keyword(s):  
Food Industry ◽  
Convective Drying ◽  
Diffusivity Coefficient ◽  
Drying Method ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Air Temperatures ◽  
Drying Curves

The efficient utilization of waste from food industry is possible after thermal treatment of the material. This treatment should be economically feasible and compromise the energy efficient drying process. The main goal of this investigation is to determine drying characteristics of nectarine pomace as a waste from food industry. The measurements were performed in an experimental dryer by combined conductive-convective drying method with disk-shaped samples of 5, 7 and 10mm thickness and 100 mm in diameter at the air temperatures of 30, 40, 50, 60 and 70oC, hot plate temperatures of 50, 60 an 70oC and air velocity of 1.5 m/s. The drying curves were compared to a few semi-theoretical mathematical models. The Logarithmic model showed the best correspondence. On the basis of experiments, it is determined that the drying process takes place in a falling rate period and it is accepted that the main mechanism of moisture removal is diffusion. The effective coefficient of diffusion was determined using experimental results by calculating the slope of the drying curves. Drying time and equilibrium moisture are determined for each experiment. Analysis of drying curves showed that the conductive-enhanced drying method reduces drying times and increases the diffusivity coefficient. The character of drying rate curves for conductive-enhanced drying was analyzed and compared with pure convective drying of nectarine pomace.

scholarly journals Effect of Temperature at Tray Position on Drying of D.ark Re.d Oni.on-slice.s at Elevated Air Velocity

2020 ◽  
Vol 9 (4) ◽  
pp. 293-296
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Moisture Ratio ◽  
Convective Drying ◽  
Flow Rate Ratio ◽  
Effect Of Temperature ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time

The convective drying process is used to dry onion-slices. The drying experiments are conducted at a drying temperature of 50oC, 60oC, 70oC, and at an air velocity of 1.99, 3.54, 5.66, and 7.52 m/s. The objective is to study the influence of tray position on drying of dark red onion. The work diverges in analyzing drying constants at air velocity beyond 2 m/s. The moisture ratio for the middle tray is greater compared to the top and bottom tray. A smaller moisture ratio is observed for 60°C compared to 50 and 70°C. Moisture removal per unit mass flow rate ratio is lowest observed for bottom tray with 60°C. The ratio of moisture content and mass flow rate for 60 and 70 °C, displays a downward trend with drying time. The randomness in the drying rate at 60 °C and 70 °C is comparatively lesser than 50 °C.

scholarly journals Applicability of Pulsed Electric Field (PEF) Pre-Treatment for a Convective Two-Step Drying Process

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 512 ◽  
Author(s):  
Robin Ostermeier ◽  
Oleksii Parniakov ◽  
Stefan Töpfl ◽  
Henry Jäger
Keyword(s):  
Electric Field ◽  
Pyruvic Acid ◽  
Acid Content ◽  
Pulsed Electric Field ◽  
Convective Drying ◽  
Quality Analysis ◽  
Drying Process ◽  
Drying Time ◽  
Treated Sample ◽  
Pre Treatment

Available literature and previous studies focus on the Pulsed Electric Field (PEF) parameters influencing the drying process of fruit and vegetable tissue. This study investigates the applicability of PEF pre-treatment considering the industrial-scale drying conditions of onions and related quality parameters of the final product. First, the influence of the PEF treatment (W = 4.0 kJ/kg, E = 1.07 kV/cm) on the convective drying was investigated for samples dried at constant temperatures (65, 75, and 85 °C) and drying profiles (85/55, 85/65, and 85/75 °C). These trials were performed along with the determination of the breakpoint to assure an industrial drying profile with varying temperatures. A reduction in drying time of 32% was achieved by applying PEF prior to drying at profile 85/65 °C (target moisture ≤7%). The effective water diffusion coefficient for the last drying section has been increased from 1.99 × 10−10 m2/s to 3.48 × 10−10 m2/s in the PEF-treated tissue. In case of the 85/65 °C drying profile, the PEF-treated sample showed the highest benefits in terms of process efficiency and quality compared to the untreated sample. A quality analysis was performed considering the colour, amount of blisters, pyruvic acid content, and the rehydration behavior comparing the untreated and PEF-treated sample. The PEF-treated sample showed practically no blisters and a 14.5% higher pyruvic acid content. Moreover, the rehydration coefficient was 47% higher when applying PEF prior to drying.

scholarly journals Kinetics Drying of Blackberry Bagasse and Degradation of Anthocyanins and Bioactive Properties

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 548
Author(s):  
Dorila E. Grández-Yoplac ◽  
Diner Mori-Mestanza ◽  
Lucas D. Muñóz-Astecker ◽  
Ilse S. Cayo-Colca ◽  
Efraín M. Castro-Alayo
Keyword(s):  
Reaction Rate Constant ◽  
Convective Drying ◽  
Water Evaporation ◽  
Total Phenolic ◽  
Order Kinetic ◽  
Drying Process ◽  
Drying Time ◽  
First Order ◽  
Order Kinetic Model ◽  
Anthocyanin Degradation

The process of drying food is necessary to preserve it; however, some bioactive compounds can be degraded during drying process. In this work, the convective drying process of Peruvian blackberry bagasse and the degradation of anthocyanins, total phenolic content (TPC), and antioxidant capacity (AC) were studied. The logarithmic model fitted well to the data and could predict the process, showing that 6 h of drying at 90 °C is enough to reach equilibrium moisture. Anthocyanin degradation followed a first-order kinetic model with reaction rate constant between 5.45 × 10−2 ± 4.68 × 10−3 and 1.21 × 10−1 ± 2.31 × 10−2 h−1, and activation energy of 25.11 kJ/mol. The highest retention (84.38%) of anthocyanins was obtained in 1 h at 50 °C and the highest degradation (68.54%) in 6 h at 90 °C. The TPC and AC increased with the drying time and temperature due to the increased water evaporation.

Sign in / Sign up

Export Citation Format

Share Document