Which of the heat pump drying technology and the traditional drying technology is more advantageous?
At present, in agriculture, food, chemicals, ceramics, medicine, mineral processing, pulp and paper, wood processing and other industries, drying is almost required in all production processes. The quality of dried materials depends on whether they are well controlled and constant. temperature. The heat pump drying technology is a gentle and close to natural drying method, which is more suitable for the drying of most heat-sensitive materials such as agricultural products and medicinal materials.
Energy efficiency comparison between heat pump drying technology and traditional drying technology
The principle of the heat pump dryer is to use the reverse Carnot principle. The gas is pressurized by the compressor to become high temperature and high pressure gas (temperature up to 100°C), which enters the heat exchanger (condenser) on the indoor side, and the refrigerant is condensed and liquefied to release high temperature heat. Heating the air in the drying room.
The materials in the drying room vaporize and evaporate the moisture in the materials in the form of hot air, and the evaporated water vapor is discharged by the dehumidification system to achieve the purpose of drying the materials. The heat pump dryer only needs to consume the electric energy used when the compressor is working, and can obtain more energy from the air. The energy efficiency ratio is as high as 400%, which is more energy-efficient than other drying methods.
1. The characteristics of traditional drying technology
For example, most of the dehydrated vegetable production still uses the traditional drying method-the drying room back to the dragon fire road heating and drying method, it has several problems:
Compared with traditional drying technology, who has the advantage of heat pump drying technology?
1. The drying temperature is too high. With traditional drying technology, the drying temperature is not easy to control. Generally, the drying temperature is around 75-90°C, while the dehydrated vegetable drying process requires that the drying temperature should not exceed 65°C.
2. The drying time is too long. Traditional drying technology requires at least 24 hours to process 1 ton of vegetables. Sometimes it takes longer to rework due to poor drying effect.
3. Large energy consumption. Traditional drying technology has low thermal efficiency, about 30%-60%. During the drying process, the heat of drying and evaporating moisture accounts for about 36%, and the loss of exhaust gas accounts for about 58%. Dry materials take away heat and The heat loss of the dryer accounts for 2% and 2% respectively, and the thermal efficiency is only 40%.
Second, the characteristics of heat pump drying technology
Compared with the traditional drying technology, who has the advantage of heat pump drying technology?
1. The drying temperature is low. The production process of heat pump drying technology is about 38-52℃ lower than traditional drying technology, that is, the heating temperature of heat pump drying technology is about 37℃.
2. Short drying time. The heat pump drying and dehydrating vegetable production process requires no more than 8 hours. Generally, it can be completed within 4 hours from preheating to product production.
3. Good drying quality. The vegetables produced by the heat pump drying process have good color and stable internal quality.
4. Low energy consumption. Because the heat pump drying process uses air circulation, the heating temperature is low, the drying time is short, and the capacity is large. Therefore, the heat pump drying process consumes less energy and is a good energy-saving product.
3. Comparison of economic and technical indicators
Compared with traditional drying technology, who has the advantage of heat pump drying technology?
The economic and technical indicators of heat pump drying technology are significantly higher than traditional drying technology, which is mainly reflected in energy saving, quality, efficiency and other aspects.
1. In terms of energy consumption:
(1) Heat pump drying: According to the test, the heater consumes 20kg of standard coal for processing 1 ton of fresh vegetables, the heat pump is 2.75kW, and the circulating fan consumes 0.2kW of electricity. Calculated by working for 4 hours, its energy consumption is 11.8kW, and the standard coal conversion factor is 407g/ (kW•h), standard coal is 4.803kg, total energy consumption is 20kg+4.803kg=24.803kg (standard coal);
(2) Traditional drying: A total of 240kg of standard coal is consumed, and the circulating fan consumes 2.4kW of electricity. The conversion factor of standard coal is 407g/(kW•h), which is equivalent to 0.977kg of standard coal. The total energy consumption is 240+0.977=240.977kg. (Standard coal).
The energy-saving efficiency ratio of the two methods is: (1-24.803/240.977)×100%=90%.
2. In terms of quality: heat pump drying technology, stable product quality, good color, and no toxic residues such as sulfur dioxide.
3. In terms of efficiency: using heat pump drying process products, the moisture content is qualified, there is no rework phenomenon, and the drying time is short.
