Feature of heat pump dryers for food&fruits

Writer： admin Time：2022-10-13 09:20 Browse：℃

1. Closed circulation drying of low-temperature air can be realized, and the quality of material drying is good. By controlling the working conditions of the device, the temperature of the hot dry air in the drying room is between 20 and 80 ° C, which can meet the high-quality drying requirements of most heat-sensitive materials; the closed cycle of the drying medium can avoid being exchanged with the outside gas Possible contamination of materials by impurities, which is especially important for food, pharmaceuticals or biological products. In addition, when the material is sensitive to oxygen in the air (easy to oxidize or explode), an inert medium can be used instead of air as a drying medium to achieve oxygen-free drying.

2. High efficiency and energy saving. The heat of the heating air in the heat pump dryer mainly comes from the sensible and latent heat contained in the warm and humid air discharged from the recovery drying room. The only energy input is the power consumption of the heat pump compressor, and the heat pump can consume a small amount of work to make it. Taking advantage of a large amount of heat, the heat pump drying device SMER (water content removed from the wet material by unit energy consumption) is usually 1.0 to 4.0 kg / kWh, while the SMER value of the traditional convection dryer is about 0.2 to 0.6 kg / kWh.

3. Convenient temperature and humidity control. When the material has high requirements on the temperature and humidity of the air entering the drying room (such as wood), the evaporation temperature and condensation temperature of the working medium in the evaporator and condenser can be adjusted to meet the material texture and appearance. Claim.

4. Useful volatile components in recyclable materials. Some materials contain volatile components (such as fragrance and other volatile components). When drying with a heat pump, in the drying room, the volatile components and water vaporize into the air together, and the air containing the volatile components passes through the evaporator. When being cooled, the volatile components therein are also liquefied and discharged together with the condensed water. The condensed water containing the volatile components can be collected and the useful volatile components can be separated by an appropriate method.

5. Environment friendly. In the heat pump drying device, the drying medium is closed in the circulation, and there is no pollution caused by the discharge of dry dust and volatile substances to the environment; the waste heat in the exhaust of the drying chamber is directly recovered by the heat pump to heat the cold and dry air. Thermal pollution of the unit to the environment.

6, can achieve multi-function. The heat pump in the heat pump drying device also has a cooling function. It can use the cooling function to achieve low-temperature processing (such as quick freezing and refrigeration) or freshness of a variety of materials in the season with less drying tasks. It can also expand the heating function of the heat pump in cold weather. Seasons provide heating for plantations (eg greenhouses) or breeding sites.

7, heat pump dryer is suitable for a wide range of materials. The materials suitable for drying are mainly a large class of materials with a temperature resistance between 20 and 80 ° C during drying, or although the materials can withstand higher temperatures, heat pumps are more energy-efficient or safer for drying. More materials have been studied and applied such as wood (such as oak), grains, seeds, edible fungi (such as mushrooms, fungus), medicinal materials (such as ginseng, etc.), seafood (such as fresh oysters, scallops, etc.), and bioactive products ( Such as cells, enzymes), tea, paper, etc.

8. Compared with other low-temperature (drying room air temperature <40 ℃) drying equipment (such as microwave drying, vacuum drying, freeze drying), due to the small initial investment in equipment and low operating costs, the heat pump dryer device has obvious economic Sex. The equipment cost of the heat pump drying device is mainly the heat pump part and the drying chamber part, in which the drying chamber part has the same requirements as the ordinary convection drying chamber, and there is no special air tightness and pressure bearing requirements.

9. Compared with ordinary drying equipment (air temperature in the drying room> 40 ℃), the initial investment of the heat pump dryer is generally higher than the air electric heating device, gas or coal-fired hot air furnace, so the initial investment of the drying equipment is generally higher Ordinary drying devices, heat pump dryers have high energy efficiency and low operating costs, and their comprehensive economics still have certain advantages.