Study on Drying Characteristics of Microalgae under Different Conditions

2013 ◽  
Vol 724-725 ◽  
pp. 296-299
Author(s):  
Chun Xiang Chen ◽  
Xiao Qian Ma ◽  
Xiao Cong Li ◽  
Wei Ping Qin
Keyword(s):  
Moisture Content ◽  
Mass Loss ◽  
Fresh Water ◽  
Chlorella Vulgaris ◽  
Drying Process ◽  
Drying Time ◽  
Drying Characteristics ◽  
Second Stage ◽  
Drying System ◽  
Two Stages

To find out an alternative of coal saving, a kind of microalgae, Chlorella vulgaris (C. vulgaris) which is widespread in fresh water was studied by digital blast drying system. The effect of the moisture content, drying thickness and temperature on the drying process of C. vulgaris were investigated. The results indicated that when the drying temperature is high, the moisture content is low and the material thickness is small, the drying time is short. The drying process of C.vulgaris can be divided into two stages, and the mass loss is mainly occurred in the second stage . The results will provide guidance for design of drying process and dryer of microalgae.

scholarly journals Influence of Different Hot Air Drying Temperatures on Drying Kinetics, Shrinkage, and Colour of Persimmon Slices

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo
Keyword(s):  
Moisture Content ◽  
Quadratic Model ◽  
Drying Process ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Drying Characteristics ◽  
Drying Temperature ◽  
Hot Air

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.

scholarly journals Optimization of Foam-Mat Drying Process of Watermelon Pulp Using Response Surface Methodology

2019 ◽  
pp. 1-11
Author(s):  
J. Isa ◽  
A. P. Olalusi
Keyword(s):  
Response Surface Methodology ◽  
Moisture Content ◽  
Response Surface ◽  
Methyl Cellulose ◽  
Drying Process ◽  
Air Velocity ◽  
Drying Time ◽  
Drying Characteristics ◽  
Moisture Content Level ◽  
Egg Albumen

Introduction: Foam mat drying involves the change of agricultural material from a high moisture content level to a stable foam which is achieved by moisture reduction mechanism. Aim: In this study, foam-mat drying process of watermelon was optimized using response surface methodology. Foaming conditions (carboxyl methyl cellulose and egg albumen) and the drying system parameters (air velocity and air temperature) were optimized using response surface methodology. Methodology: To evaluate the drying behaviour, the drying experiment was designed using design expert software using a central composite design setting variable of drying temperature (60°C – 80°C), air velocity (0.5 m/s – 2 m/s), carboxyl methyl cellulose (0.5% - 2.5%), egg albumen (5% - 15%). Twenty-two runs of the experiment were performed using different levels of variables combinations. Based on the statistical tests performed, the best model that described each response was selected using a polynomial analysis. Results: The optimum values for the drying conditions were: 77.42OC, 0.5m/s, 0.5% and 5% for temperature, air velocity, carboxyl methylcellulose and egg albumen respectively and the optimum values for the drying characteristics were: 25.07 KJ/mol, 1.7345E-10 m2/s, 29.019% (wet-basis). 0.742 g/cm3 and 540 minutes (approximately 9hrs) for activation energy, effective diffusivity, moisture content, foam density and the drying time respectively. Conclusion: The study of the foam-mat drying of watermelon pulp revealed that the inlet temperature, air velocity, CMC and egg albumen has a significant effect on its drying characteristics.

CATFISH DRYING (Clarias Batraclus) USING ‘TEKO BERSAYAP’ SOLAR DRYER

2012 ◽  
Vol 2 (1) ◽  
pp. 14-20
Author(s):  
Yuwana Yuwana
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Ambient Temperature ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Time ◽  
Ambient Relative Humidity ◽  
Solar Dryer

Experiment on catfish drying employing ‘Teko Bersayap’ solar dryer was conducted. The result of the experiment indicated that the dryer was able to increase ambient temperature up to 44% and decrease ambient relative humidity up to 103%. Fish drying process followed equations : KAu = 74,94 e-0,03t for unsplitted fish and KAb = 79,25 e-0,09t for splitted fish, where KAu = moisture content of unsplitted fish (%), KAb = moisture content of splitted fish (%), t = drying time. Drying of unsplitted fish finished in 43.995 hours while drying of split fish completed in 15.29 hours. Splitting the fish increased 2,877 times drying rate.

scholarly journals Cherry Tomato Drying: Sun versus Convective Oven

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 40
Author(s):  
Vincenzo Alfeo ◽  
Diego Planeta ◽  
Salvatore Velotto ◽  
Rosa Palmeri ◽  
Aldo Todaro
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Drying Process ◽  
Drying Time ◽  
Oven Drying ◽  
Sun Drying ◽  
Different Temperatures ◽  
Final Water Content ◽  
Drying Curves ◽  
Drying Conditions

Solar drying and convective oven drying of cherry tomatoes (Solanum lycopersicum) were compared. The changes in the chemical parameters of tomatoes and principal drying parameters were recorded during the drying process. Drying curves were fitted to several mathematical models, and the effects of air temperature during drying were evaluated by multiple regression analyses, comparing to previously reported models. Models for drying conditions indicated a final water content of 30% (semidry products) and 15% (dry products) was achieved, comparing sun-drying and convective oven drying at three different temperatures. After 26–28 h of sun drying, the tomato tissue had reached a moisture content of 15%. However, less drying time, about 10–11 h, was needed when starting with an initial moisture content of 92%. The tomato tissue had high ORAC and polyphenol content values after convective oven drying at 60 °C. The dried tomato samples had a satisfactory taste, color and antioxidant values.

scholarly journals Ultrasound Drying of Rose Hips: a Process Study

2020 ◽  
Vol 50 (1) ◽  
pp. 79-86
Author(s):  
Elena Verboloz ◽  
Marina Ivanova ◽  
Vera Demchenko ◽  
Sergey Fartukov ◽  
Nikita Evona
Keyword(s):  
Vitamin C ◽  
Moisture Content ◽  
Quality Indicators ◽  
State Standard ◽  
Raw Materials ◽  
Initial Moisture Content ◽  
Raw Material ◽  
Drying Process ◽  
Resource Saving ◽  
Drying Time

Introduction. Rose hips are rich in macro- and micronutrients. Unfortunately, heat treatment destroys most nutrients. Ultrasonic technologies make it possible to reduce the drying time and lower the temperature regime. The research objective was to adjust ultrasound technology to rose hip production in order to reduce the loss of vitamins and improve the quality indicators of the dried product. Study objects and methods. The research featured rose hips of the Rosa canina species collected in the south of Kazakhstan. This subspecies of wild rose is poor in vitamin C. Nevertheless, this shrub is extremely common in Russia and other countries of the Commonwealth of Independent States. The raw material was dried according to standard methods. One group of samples was treated with ultrasound, while the other served as control. Both groups underwent a sensory evaluation and were tested for moisture and vitamin C. Results and discussion. The rose hips were dried in a combination steam oven with a built-in ultrasonic wave generator. The research revealed the following optimal parameters of the ultrasound drying process: frequency of ultrasonic vibrations – 22 kHz, processing time – 2.5 h, temperature in the combination steam oven – +56°C, initial moisture content – 30%. The resulting product met the requirements of State Standard. The loss of moisture was 57%. According to State Standard 1994-93, the initial moisture content should be 15% or less. Time decreased from 360 min to 160 min, and the initial moisture was 13%. The experiment confirmed the initial hypothesis that ultrasonic treatment improves the drying process by improving quality indicators and preserving vitamin C in raw materials using. Conclusion. Ultrasound treatment during moisture removal from rose hips provides a resource-saving technology that fulfills an economically and socially important function.

scholarly journals SUBSTANTIATION OF ENERGY EFFICIENT REGIMES OF DRYING PRODUCTS FRACTIONAL PROCESSING OF ALFALFA

2021 ◽  
pp. 142-151
Author(s):  
Anatolii Spirin ◽  
Ihor Tverdokhlib ◽  
Ihor Kupchuk ◽  
Julia Poberezhets
Keyword(s):  
Moisture Content ◽  
Experimental Studies ◽  
Total Duration ◽  
High Energy ◽  
Theoretical Research ◽  
Electric Heater ◽  
Successful Implementation ◽  
Drying Process ◽  
Drying Time ◽  
Plant Materials

Shortage of quality feed significantly slows down the production of livestock products in Ukraine. One of the ways to overcome the crisis in the production of feed is the use of new high-energy feed, including the products of fractional processing of alfalfa. For the successful implementation of the skin type of feed, including the products of fractional processing of alfalfa, there should be an opportunity to create their reserves, feed should be canned for successful storage. The best way to preserve food is to dry it. Energy efficiency of the drying process, ie loss of nutrients, energy costs for the implementation of the process, etc. It depends on the method and its mode parameters. In this case, it is proposed to carry out the drying process in a thick layer of alfalfa pulp by active ventilation with heated air. To determine the rational parameters of the process, such as layer thickness, air flow, drying time and patents to conduct theoretical and experimental studies. Alfalfa pulp, like most wet plant materials, belongs to the capillary-porous bodies. The drying blood of these bodies has two distinct periods: constant and decreasing speeds (or the first and second drying periods). The moisture content of the material at which the transition from the first to the second period is called critical. As a result of theoretical research has obtained a dependence that determines the total duration of the drying process on a number of parameters, including initial, critical, equilibrium and final moisture content. To determine these coefficients, as well as to check the adequacy of the obtained dependence, experimental studies were conducted on a special installation. The main elements of the experimental setup are a fan, electric heater, containers with mass, shut-off, control and measuring equipment. According to the results of experimental research, graphical dependences of drying speed and process duration on regime parameters are obtained.

scholarly journals Modelling of biomass temperature in the drying process

2020 ◽  
Vol 154 ◽  
pp. 01004
Author(s):  
Ewa Golisz ◽  
Małgorzata Jaros ◽  
Szymon Głowacki
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Direct Calculation ◽  
Logistic Function ◽  
Temperature Model ◽  
Drying Process ◽  
Drying Time ◽  
Temperature Changes ◽  
Higher Temperature ◽  
Temperature Rate

The goal of the work was to propose and verify the model of temperature changes of the convective dried biomass depending on the drying time. The algebraic temperature model of the convective dried solid, giving the possibility of its direct calculation, was based on the logistic function of growth. Temperature model was verified for convective dried biomass: vegetable and wood (poplar and willow wood chips) significantly differing in initial moisture content. Parameter W in the temperature model, defined as the coefficient of temperature rate changes reaches greater values in higher temperature of drying air and for wood biomass which has lower initial moisture content. Empirically selected parameter W allows to verify the temperature model with the relative error less than 5%.

Thin-Layer Drying Characteristics of Fresh and Sun-Dried Buckwheat Hay

2021 ◽  
Vol 37 (4) ◽  
pp. 713-724
Author(s):  
Fuji Jian ◽  
Mehul Patil ◽  
Digvir S. Jayas ◽  
Jitendra Paliwal
Keyword(s):  
Activation Energy ◽  
Moisture Content ◽  
Thin Layer ◽  
Growth Time ◽  
List Type ◽  
Experimental Conditions ◽  
Drying Time ◽  
Drying Characteristics ◽  
Sun Drying ◽  
Thin Layer Drying

Highlights Thin-layer drying of fresh and sun-dried buckwheat hay was studied at 30°C to 180°C and 12.5% to 60% relative humidities. Buckwheat hay drying occurred in the falling-rate period. Partial sun-drying of the hay could reduce drying time by 50%. The D eff values of fresh flowers, leaves, and stems ranged from 1.4×10 -10 to 60×10 -10 m 2 /s. Abstract. Thin-layer drying characteristics of fresh and sun-dried buckwheat hay were studied at 30°C to 180°C, 12.5 to 60% relative humidities, and 0.2 m/s constant air velocity. The hay was harvested on three different times with a 10 to 12 d interval between the harvesting times. Half of the harvested hay was sun-dried on the field for 4 d (referred to as sun-dried hay). The drying behavior of flowers, leaves, and stems of the fresh and sun-dried hay was characterized. Moisture content of the fresh buckwheat flower was 0.777 to 1.633 (decimal dry basis), and fresh stems had a maximum moisture content of 5.64. Moisture content of the fresh hay decreased with the increase of growth time. Sun-drying on field could decrease more than half of the moisture content of the harvested fresh hay. Flowers, leaves, and stems needed varying drying times to reach their equilibrium moisture contents. The order of the drying time from the fastest to the slowest was flowers, leaves, then stems. Sun-dried and later harvested hay needed less drying time. The logarithmic model was the best fit for all drying processes of the flowers, leaves, and stems at different harvesting times and drying conditions. The effective moisture diffusivity of both fresh and sun-dried hay ranged from 1.4×10-10 to 60× 10-10 m2/s depending on different experimental conditions. The activation energy of the hay was from 21.08 to 33.85 kJ/mol. A power equation was the best equation to describe the drying constant of hay with their drying temperature. Keywords: Activation energy, Combination drying, Hay drying, Thin-layer drying, Water diffusivity.

Convective and microwave drying characteristics, energy requirement and color retention of dehydrated nettle leaves (Urtica diocia L.)

2017 ◽  
Author(s):  
Fuat Lule ◽  
Turhan Koyuncu
Keyword(s):  
Moisture Content ◽  
Air Temperature ◽  
Energy Requirement ◽  
Color Difference ◽  
Microwave Drying ◽  
Convective Drying ◽  
Drying Time ◽  
Drying Characteristics ◽  
Color Retention ◽  
Specific Energy Requirement

In this research, convective and microwave drying characteristics, energy requirement and color changes of nettle leaves (Urtica diocia L.) were reported. Samples of freshly harvested nettle leaves were dehydrated under three air temperatures of 50 °C, 60 °C and 70 °C and at three microwave power levels of PL-1, PL-2 and PL-3. Selected drying air velocity was 0.30 m/s for all temperatures. This is coming from the fact that it was understood from the preliminary studies that the temperature less than 50 °C and the air speed more than 0.30 ms-1 increase the drying time and energy requirement, extremely for these products. Nettle leaves were dehydrated from the initial moisture content of 320 (percentage dry basis) to a final moisture content of 7 % to 9 %. During convective drying experiments, product were weighted automatically by the balance per (5 to10) min. Data were transferred to the computer and processed by a software. During microwave drying, the product were weighted and data recorded manually per (15 to 60) min. The influence of drying method, drying air temperature and microwave power level have also been studied. Hunter L, a, b values system was also used to evaluate changes in total color difference (DE) on dried products. The results showed that convective drying air temperature and microwave oven power levels influenced the total drying time, total energy requirement, specific energy requirement and color difference for nettle leaves. The minimum specific energy requirement were determined as 6.95 kWhkg-1 and 23.63 kWhkg-1 for 70 °C and PL-2 respectively. 70 °C drying air temperature and PL-3 was found to yield better quality product in terms of color retention of Hunter L, a, b and DE. As a result, to reduce drying energy consumption and to keep better color retention, convective drying can be recommended for this application.

Analytic Study on On-Line Model of Moisture in Hot Air Drying Process of Grain

2017 ◽  
Vol 872 ◽  
pp. 360-372
Author(s):  
Zhi Wei Mai ◽  
Bi Ying Wang ◽  
Chang You Li
Keyword(s):  
Moisture Content ◽  
Cross Flow ◽  
Drying Rate ◽  
Drying Process ◽  
Counter Flow ◽  
Drying Characteristics ◽  
Concurrent Flow ◽  
Content Ratio ◽  
Real Time Tracking ◽  
Drying Technology

This study aims to review variation pattern of moisture content ratio of grains in deep-bed drying process, guide the drying technology design, realize real-time tracking and regulation in drying process, improve the quality of drying process and reduce energy consumption. Based on the moisture diffusion model in thin layer drying process, the principle of mass conservation of deep drying process, state function and irreversible thermodynamics analytic method, we have established and solved basic equations of deep-bed drying of grains, obtained the moisture content ratio of grains and analysis formula of drying velocity distribution in processes of concurrent flow drying, counter flow drying, cross-flow drying and standing drying and resolved the sustained decreasing drying process of grains in the concurrent flow drying and extreme point of drying rate in the counter-flow drying. Under the same conditions of temperature, humidity and air output, the drying velocity in counter-flow drying significantly higher than that in the concurrent flow drying. It means the energy utilization effects in counter-flow drying is better than that in the concurrent flow drying. Drying characteristics of grains in cross-flow drying and standing flow drying are the same, while drying rates in inlet-air side and outlet-air side vary widely. It means that when the layer thickness is 0.5m and the moisture content is over 20%, the drying rate in outlet-air side is nearly zero and the drying uniformity is bad. Tests on 5HP-3.5 recirculation drier shows that maximum deviation between analytic value and measured value in deep drying process is 0.69% and the range scope is -0.27%-0.69%. From the drying characteristics of grains, deviations mainly come from instrument detection deviations. The analytic method has important significance for realizing real-time tracking and regulation in drying process, guiding drying technology design, reducing energy consumption, increasing drying rate and drying machine capacity.

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