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Dadaev Gani Toshxodjayevich, Tashkent state technical university, researcher, deputy dean of the machine-building faculty Safarov Jasur Esirgapovich, Tashkent state technical university, dean of the machine-building faculty E-mail: jasursafarov@yahoo.com
IMPROVING ENERGY-SAVING SOLAR DRYING PLANT FOR DRYING DIETARY FOOD HERBS - MOTOR (ALLIUM MOTOR)
Abstract: The article describes the improvement of energy-saving solar drying plant for drying dietary food herbs — motor (Allium motor). The value of the equilibrium moisture content significantly affects the estimates of drying intensity indicators. At the same time, the asymptotic value looks reliable, which is especially evident when comparing empirical points and approximated graphs of the drying rate. Taking into account the neglect of the initial accelerating stage, the graphs of the drying curves and the drying speed do not reveal periods of constant and falling drying speed and the curves have the appearance similar to those known in the literature on the drying of herbaceous materials.
Keywords: drying, dietary food herbs, solar dryer.
According to the UN Food and Agriculture Or- in: A. V. Lykov, A. S. Ginzburg, B. S. Sazhin, S. G. Il-ganization, in 2050, to meet the demand for food, the yasov, V. V. Krasnikov, M. Akkurf, D. Bahrus, B. Bala, annual volume of world crop and livestock produc- A. K. Atyhanov, K. M. Hazimov, B. J. Babayev, tion should increase by 60% compared to 2006 [1]. N. R. Avezova, S. A. Lutpullaev, R. A. Zakhidov, In the world each year, due to spoilage, losses of grain N. R. Yusupbekov, O. F. Safarov, J. N. Mukhitdinov, products by 30%, root crops, fruits and vegetables by A. A. Artikov, Kh. S. Nurmuhamedov, J. P. Mukhid-40-50%, oilseeds, meat and dairy products by 20% dinov, H. F. Juraev, J. M. Kurbanov, K. O. Dodaev, and fish by 35% [2]. Z. S. Iskandarov, K. T. Norkulova and others. Their
In the years of independence, special attention is research and development is aimed at improving instal-paid to the cultivation and effective development of lations and drying processes in order to obtain high-the industry processing agricultural products. As a quality end products.
result of the program activities carried out in this di- They developed the scientific basis for the processes rection, including the provision of quality processing of drying capillary-porous materials, gave practical rec-of agricultural and forestry products, tangible results ommendations for the introduction of modern tech-have been achieved in the production of import-sub- nologies for drying materials of plant origin. stituting and export-oriented food and pharmaceuti- At the same time, the use of installations for drying cal products. dietary and food grasses with the intensification of the
Scientific research on the development of tech- technological process makes it possible to obtain the fi-nology and hardware design processes for drying nal product with preservation ofbiological active com-and processing dietary food herbs were engaged ponents.
Analysis of the kinetics of drying dietetic food the experimental values of the weight of the sample herbs motor (Allium motor) [2-4]. Table 1 presents and the temperature in the drying unit.
Table 1. - Experimental values of the sample weight and temperature in the drying unit
Time, t min 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210
Temperature, T, 0C 24 30 57,7 60 60 60 60 58 58,5 59 60,7 63 62 64,2 63 65 67 67 67 70 72 72
Weight, P g 229 225 216 197 170 151 133 108 90 75 72 56 47 39 37 35 34 33 32 30 27 27
In order to go from weight to moisture and moisture content, it is necessary to have data on the limit of moisture content achieved at infinity, or the weight of absolutely dry material. For leveling the experimental errors, we estimate the desired value as the horizontal asymptote to the graph (Fig. 1) of the function P=f(t).
We assume that the maximum weight corresponds to the weight of the dry material under the assumption that an equilibrium moisture content of zero is reached. The basis of this assumption is low relative humidity and high temperature.
The nature of the graph P=f(t) corresponds to the formula P = a1eblt + a2eb2t + a5. With this a2 < 0, a4 < 0, a a5 > 0 Given the initial conditions
\P (0) = P0 ^ K + a3 + a5 = P0 ^ k = P0 - ai - a3
[ P (0) = 0 [ a1a2 + a3a4 = 0 [ a4 =-a1a2/ a3
The results of the approximation with large specific coefficients of the end points are shown in Fig.1.
Asymptotic estimate P (<») with the use of large specific coefficients to the end points and subject to the above limitations gives a5 = P (co) = 22,76 a.
With this a1 = -4,3236-103, a2 =-0,0296, a3 = 4,5299-103, a4 = 0,0283, a5 = 22,688.
Figures 2 and 3 show the drying curves, where the ordinate is expressed in moisture content by the (P - a5)
formula W =
and through the moisture
(P - a5 ) formula W = ±-5j-100%
Repeated approximation already with the known and the same specific coefficients on the points gives: a1 = -9,9398 404, a2 = -0,0281, a3 = 9,9604T04, a4 =-0,0281.
1 - initial approximation; 2 - approximating function.
Figure 1. Approximation result P=f(t)
Calculations on new values ofparameters, and drying curves, and drying speed curves do not differ significantly from calculations on asymptotic parameters.
In fig. Figure 4 shows the curve for the rate of grass drying; the motor in terms of moisture content is the drying rate, and in fig. 5 shows the drying rate curve, expressed in the coordinates of the humidity — the drying rate.
In fig. 5 are marked by dots of grass drying rate dW AW
motor, obtained as = according to experimental data.
Figure 2. The change in moisture content over time
-
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o \
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50
100
150
200
t, min
250
Figure 3. Change in humidity over time
Analysis of the results allows us to conclude:
- the value of the equilibrium moisture content significantly affects the estimates of drying intensity indicators. At the same time, the asymptotic value looks reliable, which is especially evident when comparing empirical points and approximated drying rate graphs;
- even taking into account the neglect of the initial accelerating stage, the graphs of the drying curves and the drying speed do not reveal periods of constant and falling drying speed and the curves
look similar to those known in the literature on the drying of herbaceous materials;
- the impossibility of applying traditional methods of calculation and design, based on the presence of two specific periods, in this case is aggravated by the unpredictable weather parameters of the natural energy source of solar thermal plants that change in advance.
We proceed to the analysis of the ratios of internal and external resistance to moisture transfer in the process of drying the materials in question.
Figure 4. Drying speed curve
Figure 5. Moisture Drying Curve
Reference:
1. Food and Agriculture Organization of the United Nations. The state of food and agriculture. Climate change, agriculture and food security. Rome, 2016.- 210 p.
2. Food and Agriculture Organization of the United Nations.Global initiative on food loss and waste reduction 2015.Rome, 2015.- 8 p.
3. Safarov J. E., Dadayev G. T. The results of an experimental study of the accumulation of energy in a solar drying plant. // Austrian Journal of Technical and Natural Sciences.-Austria. 2017. № 9-10.-P. 60-64.
4. Safarov J. E., Dadaev G. T. The study of the drying process of the motor plant (Allium motor). // Chemistry and chemical technology.- Tashkent, 2017. № 5.- P. 35-38.
