The effect of aeration rate and comparison of aeration energy in different methods

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Increasing the Iranian Pistachio speed of the blown air to an optimal extent reduces the drying time, but if we increase the hot air speed too much, the air will leave the drying system without saturation of moisture, which has a high degree of energy loss.

Research conducted in the United States, from which the data obtained are in accordance with the climatic conditions, has shown that at accumulation depths of 45, 90 and 137 cm, pistachios using aeration method with a wind speed of 0.36 and 0.51 m in Seconds dried in the same amount of time, but at 0.2 m / s the moisture loss was significantly slower. According to the results, in the aeration method (with ambient air) the appropriate value of air velocity is 0.36 meters per second and higher aeration speed has very little effect in accelerating the drying process. Comparing the cost of energy related to different speeds also showed that the amount of energy consumed at a speed of 0.36 meters per second is half the speed of 0.51 meters per second, while they do not differ in terms of reducing the drying time.

The effect of fuel consumption and comparison of thermal energy in different methods

Data from research in the US state of Califoia show that the use of temperatures above 71 ° C (commonly used by processors) significantly reduces the time and cost of drying pistachios. Reduces so that energy consumption at temperatures of 93 to 138 ° C is almost half the energy used at temperatures of 71 ° C (Table 2). Evaluation of the quality of dried pistachio seeds at different temperatures shows that the temperature of 93 ° C had no detrimental effect on pistachios except for an increase in the number of free keels, but the taste of roasting at 115.5 and 138 ° C. It was recognizable.

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Suggestions for better use of dryers

In view of the above, and since one of the most energy-consuming processes in pistachio processing is the drying step, so to save energy in this process, sometimes with a slight change in the design of such systems can be Significantly reduces their energy consumption.

Effective steps that can be taken to reduce energy consumption in dryer systems include:

Choosing the right type of dryer: Choosing a dryer that has a higher thermal efficiency should be considered. The higher the thermal efficiency of the dryer, the more energy the fuel is used to dry the product and the less is wasted. For example, the table below shows the thermal efficiency of different drying methods for the co crop (according to Table 3).

Choosing the optimal aeration speed: As previously described, high aeration speeds only increase energy consumption and have little effect on speeding up the drying process.ش