RELATIONSHIP BETWEEN A SOLAR DRYING MODEL OF RED PEPPER AND THE KINETICS OF PURE WATER EVAPORATION (II)

1997 ◽  
Vol 15 (5) ◽  
pp. 1433-1455 ◽  
Author(s):  
Victor Passamai ◽  
Luis Saravia
2005 ◽  
Vol 36 (5) ◽  
pp. 425-430 ◽  
Author(s):  
A. M. Pavlenko ◽  
B. I. Basok

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
James Owusu-Kwarteng ◽  
Francis K. K. Kori ◽  
Fortune Akabanda

The objective of this work was to determine the effects of blanching and two drying methods, open-sun drying and natural convection solar drying, on the quality characteristics of red pepper. A 2 × 3 factorial design with experimental factors as 2 drying methods (open-sun drying and use of solar dryer) and 3 levels of pepper blanching (unblanched, blanched in plain water, and blanched in 2% NaCl) was conducted. Dried pepper samples were analysed for chemical composition, microbial load, and consumer sensory acceptability. Blanching of pepper in 2% NaCl solution followed by drying in a natural convection solar dryer reduced drying time by 15 hours. Similarly, a combination of blanching and drying in the solar dryer improved microbial quality of dried pepper. However, blanching and drying processes resulted in reduction in nutrients such as vitamin C and minerals content of pepper. Blanching followed by drying in natural convection solar dryer had the highest consumer acceptability scores for colour and overall acceptability, while texture and aroma were not significantly (p>0.05) affected by the different treatments. Therefore, natural convection solar dryer can be used to dry pepper with acceptable microbial and sensory qualities, as an alternative to open-sun drying.


2012 ◽  
Vol 610-613 ◽  
pp. 296-299
Author(s):  
Xin Jie Li ◽  
Dan Nan Jiang ◽  
Yue Jun Zhang

In order to learn the ClO2 decay behaviour in tap water, the kinetics of ClO2 decay in pure water was studied. Under the conditions of tap water treatment and keeping away from light, the effects of temperature and pH on ClO2 degradation were investigated. The results show that the ClO2 decay reaction in pure water is the first-order with respect to ClO2, the decay rate constants increase with increase in temperature or pH. At pH=6.87, the rate constants are 0.012h-1(15°C), 0.017h-1(25°C), 0.023h-1(35°C), and 0.029h-1(45°C), respectively. At 25°C, the rate constants are 0.0083h-1(pH=4.5), 0.0111h-1(pH=5.5), 0.0143h-1(pH=6.5), 0.0222h-1(pH=7.5), and 0.0351h-1(pH=8.5), respectively. The experimental data prove that ClO2 is more stable in acidic or lower temperature water than in neutral, alkalescent, or higher temperature water.


2000 ◽  
Vol 65 (12) ◽  
pp. 963-974 ◽  
Author(s):  
Zeljko Grbavcic ◽  
Zorana Arsenijevic ◽  
Radmila Garic-Grulovic

A fluid bed dryer with inert particles was used for the drying of suspensions and pastes. The effects of the operating conditions on the dryer throughput and on the product quality were investigated. Experiments were performed in a cylindrical column 215 mm in diameter and 1200 mm in height with 0.925 mm diameter glass spheres as the fluidizing media. Cineb fungicide, copper hydroxide and pure water were used as the feed material. With respect to the main efficiency criteria, i.e., specific water evaporation rate, specific heat consumption and specific air consumption, a fluid bed dryer with inert particles represents a very attractive alternative to other drying technologies. A high drying efficiency results from the large contact area and from the large temperature difference between the inlet and outlet air. A rapid mixing of the particles, due to aggregative fluidization and mechanical agitation, leads to nearly isothermal conditions throughout the bed. In our experiments, suspensions and very dense pastes were successfully treated. Suspension and product hold-up in the bed varies between 6 and 8 % by mass and a product with the same particle size as the raw material is obtained.


Author(s):  
А.С. ДАНИЛЬЧЕНКО ◽  
Т.Г. КОРОТКОВА ◽  
С.Ю. КСАНДОПУЛО

Рассмотрена кинетика сушки послеспиртовой барды при 60°С. Объектом исследований была модельная смесь, состоящая из воды, белков, жиров и растворимых углеводов. Представлены результаты исследований кинетики испарения воды и смесей вода–масло, вода–белок, вода–сахар, вода–масло–белок–сахар, помещенных в чашку Петри. Процесс испарения в изотермических условиях протекал в сушильном шкафу Memmert. Установлено, что добавление вещества в воду снижает скорость испарения воды в периоде постоянной скорости сушки, в периоде падающей скорости сушки продолжительность испарения возрастает. По результатам кинетики сушки модельных смесей можно определять коэффициенты активности компонентов и проводить исследование процесса сушки реальных смесей при проектировании сушилок. The kinetics of drying of the distillery dregs at 60°C is considered. The model mixture containing water, proteins, oils and soluble carbohydrates was the object of research. The results of experimental studies of the kinetics of evaporation of water and mixtures of water-oil, water-protein, water-sugar, water-oil-protein-sugar, placed in a Petri dish, are presented. Evaporation under isothermal conditions was carried out in a Memmert drying cabinet. It is established that the addition of the substance into the water reduces the evaporation rate of water in the period of constant drying speed, the duration of evaporation in the period of falling drying speed increases. According to the results of the kinetics of drying model mixtures, it is possible to determine the activity coefficients of the components and conduct a study of the drying process of real mixtures in the design of dryers.


1967 ◽  
Vol 45 (14) ◽  
pp. 1619-1629 ◽  
Author(s):  
A. Queen

The activation parameters ΔH≠, ΔS≠, and ΔCP≠ for the hydrolyses of a series of alkyl chloroformates and dimethylcarbamyl chloride in water have been determined. The results indicate that, with increasing electron donation to the chlorocarbonyl group, the mechanism changes from bimolecular to unimolecular (SN1) displacement at this position. For isopropyl chloroformate, some concurrent alkyl–oxygen bond fission is also indicated. The bimolecular mechanism involves reversible addition of water to the carbonyl group followed by ionization of the carbon–chlorine bond.


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