Research on Constant-Temperature Drying Test of Cotton Straw and Regression Analysis of Drying Rate

2012 ◽  
Vol 472-475 ◽  
pp. 1645-1651
Author(s):  
Jian Jun Hu ◽  
Sheng Qiang Shen ◽  
Ting Zhou Lei ◽  
Hao Huang ◽  
Quan Guo Zhang
Keyword(s):  
Regression Analysis ◽  
Constant Temperature ◽  
Initial Moisture Content ◽  
Drying Rate ◽  
Regression Equations ◽  
Drying Time ◽  
Drying Curves ◽  
Drying Technology ◽  
Drying Conditions ◽  
Two Stages

Constant-temperature drying tests for cotton straw under different conditions were performed with an integrated thermal analyzer, and the influence of different drying conditions on the drying process was analyzed. The process was divided into preheating stage, constant-rate drying stage, and decelerating drying stage. Regression analysis was conducted for drying curves at the latter two stages, and then the drying time at the critical point was determined. Regression equations of drying rate at these stages were produced. Research results showed that the decelerating drying stage of cotton straw included two decelerating intervals, and the best ending point of the drying of the cotton straw that had an initial moisture content of 56.1% and a drying temperature of 100°Cwas 600s, thus providing experimental data and reference for research on drying technology of straws.

Experimental Research and Regression Analysis for Constant Temperature Drying of Wheat Straw

2011 ◽  
Vol 194-196 ◽  
pp. 1442-1448
Author(s):  
Jian Jun Hu ◽  
Quan Guo Zhang ◽  
Hao Huang
Keyword(s):  
Regression Analysis ◽  
Moisture Content ◽  
Wheat Straw ◽  
Constant Temperature ◽  
Initial Moisture Content ◽  
Regression Equations ◽  
Drying Time ◽  
Drying Temperature ◽  
Drying Section ◽  
The Impact

The constant temperature drying experiment on wheat straw at different initial moisture content and drying temperature were made with comprehensive thermal analyzer. The impact of initial moisture content, drying temperature and drying time on wheat straw procedure were reviewed, and the optimum drying result of wheat straw were gotten when initial moisture content was 32.5% and drying temperature was 100°C .The process of wheat straw drying was divided into three sections about preheating, constant temperature and falling rate drying. Regression equations on different sections were established by regression analysis, the result show that parabolic equation in preheating section, linear equation in constant rate drying section and power curve in falling rate drying section. Experiment data and reference frame from conclusion above were useful to crop straw drying technology.

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 THE EFFECT OF THE FILLING RATIO ON THE OPERATING CHARACTERISTICS OF AN INDIRECT DRUM DRYER

2020 ◽  
Vol 60 (1) ◽  
pp. 49-55
Author(s):  
Jan Havlík ◽  
Tomáš Dlouhý ◽  
Michel Sabatini
Keyword(s):  
Specific Energy Consumption ◽  
Filling Ratio ◽  
Operating Characteristics ◽  
Drying Time ◽  
Green Wood ◽  
Operational Characteristics ◽  
Rotary Drum ◽  
Drying Curves ◽  
The One ◽  
Drying Conditions

This article investigates the effect of the filling ratio of the indirect rotary dryers on their operating characteristics. For moist biomass drying before combustion, the use of indirect drum dryers heated by a low pressure steam has proven to be highly suitable. Regarding the design of new dryers, it is necessary to experimentally verify the operating characteristics for specific materials and drying conditions. For this purpose, a set of experiments on a steam heated rotary drum dryer were carried out with green wood chips containing 60 to 66 wt% of moisture. The following operational characteristics of the dryer were experimentally determined: drying curves describing the process, square and volumetric evaporation capacities and drying heat consumptions. Based on the experimental results, the effect of various drum filling by dried material on the mentioned operating characteristics was analysed. On the one hand, higher drum filling ratio increases the drying time, on the other hand, the evaporation capacity also increases, while the specific energy consumption does not significantly alter. The maximum value of the evaporation capacity was reached when the drum was filled to 20 wt%. When the filling ratio was increased to 25 wt%, the evaporation capacity experienced almost no change.

The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment

2014 ◽  
Vol 69 (9) ◽  
pp. 1859-1866 ◽  
Author(s):  
Hui-Ling Wang ◽  
Zhao-Hui Yang ◽  
Jing Huang ◽  
Li-Ke Wang ◽  
Cheng-Liu Gou ◽  
...  
Keyword(s):  
Sample Thickness ◽  
Coefficient Of Determination ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
Dewatered Sludge ◽  
Drying Curves ◽  
Sludge Drying ◽  
The Impact

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm3 had the best drying performance at each level of temperature, which could save 35–45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm3 was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.

scholarly journals Effect of pretreatments on drying behavior of eggplant

2019 ◽  
Vol 17 (1) ◽  
pp. 105-109
Author(s):  
Md Junaeid Khan ◽  
Farjana Yeasmin ◽  
Md Nazrul Islam ◽  
Raju Ahmmed ◽  
Pabitra Chandra Das ◽  
...  
Keyword(s):  
Constant Temperature ◽  
Rate Constant ◽  
Hot Water ◽  
Effect Of Temperature ◽  
Constant Thickness ◽  
Drying Rate ◽  
Fresh Sample ◽  
Drying Time ◽  
Preservation Method ◽  
Drying Behavior

Eggplant is a familiar and admired vegetable in Bangladesh. It is a highly perishable vegetable and cannot be preserved long. Drying is an ancient preservation method used to extend shelf-life of fruits and vegetables. Different Pretreatments may affect the drying kinetics of foods. A study was conducted to evaluate how pretreatments affect the drying behavior of eggplant. Proximate composition of fresh eggplant was analyzed. The samples of constant thickness (8 mm) were dried at 50°C, 55°C and 60°C to determine the effect of temperature on drying rate constant, while for determining the effect of thickness on rate constant, eggplant slices of 4, 6 and 8 mm thicknesses were dried at a constant temperature of 55°C. It was observed that, drying rate decreased with the increase in thickness and the index ‘n’ was found to be 0.89 at 55°C. Under similar drying condition at constant thickness (8 mm), drying time showed an inverse relationship with temperature. The activation energy (Ea) was calculated as 3.242 Kcal/g-mole. Eggplant slices having the highest thickness (8 mm) were blanched at 70°C, 75°C and 80°C for 1, 2 and 2.5 minutes, respectively using hot water bath to determine the effective blanching time and temperature. It was observed that the samples blanched at 75°C and 80°C for 2 minute were enough to inactivate the enzymes. Pretreated (blanched, sulphited and blanched plus sulphited) eggplant slices having constant thickness (8 mm) were dried at constant temperature of 55°C. The drying time was influenced by pretreatments. The highest drying rate was observed for eggplant slices with blanched plus sulphited (5% KMS solution) samples while eggplant slices with 5%KMS solution dipped for 10 minutes showed the lowest drying rate. In case of fresh slices, drying time was lower than blanched and sulphited samples but higher than blanched plus sulphited samples. Pretreatment was also found effective on the color changes (preservation or degradation). Blanching gave a bright color compared to fresh sample but less bright compared to sulphited samples. In case of SO2 retention, blanched plus sulphited sample showed higher retention than sulphited sample. Sulphited sample retains 44.8 ppm SO2/100g of sulphited sample, while the blanched plus sulphited sample retains 280 ppm SO2/100 g of blanched plus sulphited sample. J. Bangladesh Agril. Univ. 17(1): 105–109, March 2019

Effect of Drying on Physical Qualities and Sensory Evaluation of Herbal Germinated Brown Rice by Hot Air: Turmeric and Roselle

2013 ◽  
Vol 372 ◽  
pp. 420-423
Author(s):  
Khwanruedi Sangchum ◽  
Yutthana Tirawanichakul ◽  
Supawan Tirawanichakul
Keyword(s):  
Moisture Content ◽  
Sensory Evaluation ◽  
Initial Moisture Content ◽  
Brown Rice ◽  
Ambient Air ◽  
Drying Rate ◽  
Germinated Brown Rice ◽  
Rice Drying ◽  
Drying Conditions ◽  
Cie Lab

The object of this project was to study the effect of drying temperature on physical quality and sensory evaluation of germinated brown rice soaking with tumeric and roselle. The drying was run under the conditions of drying temperatures of 80-100°C and air velocity of 7.3 m/s. Initial moisture content of brown rice samples was of 54-55% dry-basis and was dried until the final moisture content reached to 20-25% dry-basis. After drying, the rice was tempered and then was ventilated by ambient air until its moisture content reached to 14-15% dry-basis. The experiment showed that highest drying rate is incident at 100°C. For physical qualities analysis, the results showed that the drying air temperature does not affect to head rice yield, fissured kernels, chalky grain and color (L*, a*, b* CIE-lab unit) of herbal germinated brown rice. In addition, herbal germinated brown rice drying can maintain low percentage of chalky grain compared to commercial brown rice. The soaking solution was not affect to drying rate. Finally, the sensory evaluation showed that the herbal germinated brown rice dried with all drying conditions was acceptable taste (>5).

scholarly journals Experimental Study on Super-Heated Steam Drying of Lignite

2011 ◽  
Vol 347-353 ◽  
pp. 3077-3082 ◽  
Author(s):  
Yong Chun Shi ◽  
Jie Li ◽  
Xuan You Li ◽  
Jing Wu ◽  
Mao Gang Wu ◽  
...  
Keyword(s):  
Power Plants ◽  
Experimental System ◽  
Drying Rate ◽  
Drying Process ◽  
Operation Conditions ◽  
Hot Air ◽  
Application Potential ◽  
Drying Technology ◽  
Two Stages ◽  
Steam Drying

This paper applies super-heated steam drying technology to improve the quality of lignite. A unique experimental system was built up. In order to obtain the optimum operation conditions, the drying kinetics was measured. The temperature range of super-heated steam was from 120 to 200°C. The results showed that the drying process of super-heated steam drying of lignite can be well depicted by two stages, as a constant drying rate stage followed by a falling drying rate stage. The comparison of drying process to the hot air drying showed the superior advantages of super-heated steam drying on safety, drying capacity and energy conservation. Analysis shows the huge application potential of lignite in power plants by means of the super-heated steam drying.

scholarly journals Effects of Infrared-Assisted Refractance Window™ Drying on the Drying Kinetics, Microstructure, and Color of Physalis Fruit Purée

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 343
Author(s):  
Luis Puente-Díaz ◽  
Oliver Spolmann ◽  
Diego Nocetti ◽  
Liliana Zura-Bravo ◽  
Roberto Lemus-Mondaca
Keyword(s):  
Statistical Tests ◽  
Coefficient Of Determination ◽  
Drying Process ◽  
Chi Square ◽  
Ir Radiation ◽  
Drying Time ◽  
Drying Curves ◽  
Effective Diffusivities ◽  
Drying Conditions ◽  
Fruit Purée

The objective of this work was to study the influence of the drying temperature, infrared (IR) radiation assistance, and the Mylar™ film thickness during Physalis fruit purée drying by the Refractance Window™ (RW™) method. For this, a RW™ dryer layout with a regulated bath at working temperatures of 60, 75, and 90 °C, Mylar™ thicknesses of 0.19, 0.25, 0.30 mm and IR radiation of 250 W for assisting RW™ drying process was used. Experimental curves data were expressed in moisture ratio (MR) in order to obtain moisture effective diffusivities (non-assisted RW™: Deff = 2.7–10.1 × 10−10 m2/s and IR-assisted RW™: Deff = 4.2–13.4 × 10−10 m2/s) and further drying curves modeling (Page, Henderson–Pabis, Modified Henderson–Pabis, Two-Term, and Midilli–Kucuk models). The Midilli–Kucuk model obtained the best-fit quality on experimental curves regarding statistical tests applied (Coefficient of Determination (R2), Chi-Square (χ2) and Root Mean Square Error (RMSE). Microscopical observations were carried out to study the RW™ drying conditions effect on microstructural changes of Physalis fruit purée. The main findings of this work indicated that the use of IR-assisted RW™ drying effectively accelerates the drying process, which achieved a decrease drying time around 60%. Thus, this combined RW™ process is strongly influenced by the working temperature and IR-power applied, and slightly by Mylar™ thickness.

Relationship between air conditions and the drying rate of thin-layers of grass

1993 ◽  
Vol 121 (1) ◽  
pp. 21-28 ◽  
Author(s):  
W. J. Lamond ◽  
R. Graham
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Variable Parameter ◽  
Major Effect ◽  
Thin Layers ◽  
Regression Equations ◽  
Agricultural Engineering ◽  
Thin Layer Drying ◽  
Harvesting Method ◽  
Drying Curves

SUMMARYA series of 240 thin-layer drying runs carried out in 1988 and 1989 at the Scottish Centre of Agricultural Engineering were analysed to find out which factors influenced the rate of drying of grass mixtures. The grass used in the experiments was cut by hand, by a mower without conditioner or by a mower with conditioner. The experiments covered a range of air conditions from 16·0 to 40·4 °C temperature and 24·4 to 82·8% relative humidity. By fitting curves to the experimental data it was shown that the drying curves could be simulated by a two-parameter, exponential equation. Analysis of the data showed that the experimental results could be adequately represented by holding one of the parameters fixed and fitting the curves with only one parameter varying. The variable parameter, called the drying coefficient, was dependent on harvesting method and related to drying air temperature, initial moisture content and ratio of leaf area to stem area. A regression equation relating the drying coefficient to these variables for conditioned and unconditioned grass is presented.Predictions from the regression equations indicated that the temperature of the drying air had a major effect on the drying coefficient. Both the initial moisture content of the samples and ratio of leaf to stem had a smaller influence on the coefficient over their likely range.

scholarly journals Performance Evaluation of a Forced Convection Mixed-Mode Solar Grain Dryer with a Preheater

2021 ◽  
Vol 10 (4) ◽  
pp. 41-51
Author(s):  
Johannes P. Angula ◽  
Freddie Inambao
Keyword(s):  
Forced Convection ◽  
Thermal Efficiency ◽  
Mixed Mode ◽  
Total Mass ◽  
Initial Moisture Content ◽  
Food Preservation ◽  
Drying Rate ◽  
Drying Time ◽  
Solar Dryer ◽  
Maize Cobs

In this study the performance of a forced convection mixed-mode solar grain dryer integrated with a preheater was evaluated. The type of grains used in the experiment were 72 freshly harvested maize cobs with a total mass of 17 kg. The experiment was conducted at various airflow speeds and preheater temperatures ranging from 0.5 m/s to 2 m/s and 30 ℃ to 40 ℃, respectively. The aim of the study was to improve the performance of an existing indirect solar dryer which was converted to a mixed-mode solar dryer. The initial thermal efficiency of the indirect solar dryer before modification was 36 %. The results from the experiment indicated a maximum thermal efficiency of 58.8 % with a corresponding drying rate of 0.0438 kg/hr. The minimum thermal efficiency for the mixed-mode solar grain dryer system was 47.7 %, with a corresponding drying rate of 0.0356 kg/hr. The fastest drying time of maize cobs was achieved in 4 hours and 34 minutes from an initial moisture content of 24.7 % wb to 12.5 % wb. The findings show a significant improvement in the dryer system's performance. This is a clear indication that operating a solar dryer system in mixed-mode operation with forced convection and the assistance of a preheater or backup heater can significantly improve drying processes and increase food preservation.

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