一、工作原理与适用范围 Working principle and scope of application
Heat pump drier utilizes the reverse Carnot's principle to absorb the heat of air and transfer it to the room to realize the temperature increase of the drying room and cooperate with corresponding equipment to realize drying of materials. The heat pump drier recycles the sensible heat and potential heat contained in the wet and hot air exhausted by the drying room while operating, the energy that shall be input is the power consumption of heat pump compressor only, and the compressor has the advantage that a lot of heat can be gathered and transferred by consuming a small amount of power, therefore, heating efficiency of heat pump drying unit is much larger than that of other drying equipment and it can realize the effects of energy conservation and emission reduction.
Heat pump drying unit is mainly suitable for dehydration and drying of agricultural and sideline products, such as tremella, melon seeds, peanuts, fruits and vegetables, meat products, casing, tobacco, mushrooms, medlar, grain, dried bean milk cream in tight rolls, marine products, traditional Chinese medicinal materials. It is also widely used in chemical aspect, for example, drying of paper products, wood, sludge, gypsum, clay, coal slime, etc. In the industrial hot water aspect, it can also meet meet the requirements of constant temperature of electroplate liquid of electroplate factory, heating and heat preservation of high-temperaturehot-water of slaughter house, supply of star ho high temperature hot water and high-temperature hot water of industrial enterprises, and drying of bedding article.
Efficient and energy-saving. Heat pump drying unit’s SMER (Specific Moisture Extraction Rate ) is generally 1.0～4.0kg/kWh and SMER value of traditional convection drier is about 0.2～0.6kg/Kwh.
It can realize low-temperature air closed cycle drying and has good material drying quality. Through controlling the working condition of unit, the temperature of hot and dry air in the drying room is at 20～80℃. It can meet the high quality drying requirements of most of the heat sensitive materials; closed cycle of drying medium can prevent the impurity contamination possibly brought by exchange with external gas to the materials, which is very important for food, drugs or biological products. In addition, when the materials are sensitive to the oxygen in the air (easy for oxidation or burning e xplosion, the inert medium can be used as a drying medium instead of air to realize anaerobic drying.
It is environment-friendly. The drying medium conducts a closed cycle in the hot pump drying unit without contamination of material dust, volatile substance and peculiar smell brought by discharge of drying waste gas to the environment; the afterheat in the exhaust gas of drying room is directly recycled by heat pump to heat the cool and dry air without thermal pollution of unit to environment.
Compared with other low-temperature (inlet air temperature of drying room<40℃) drying="" units="" (such="" as="" microwave="" drying,="" vacuum="" drying="" and="" freeze="" drying),="" heat="" pump="" drying="" unit="" has="" obvious="" economical="" efficiency="" due="" to="" small="" initial="" investment="" of="" equipment="" and="" low="" operation="" cost.="" the="" heat="" pump="" drying="" unit="" is="" mainly="" composed="" of="" heat="" pump="" and="" drying="" room,="" of="" which="" the="" drying="" room="" has="" the="" same="" requirements="" with="" convection="" drying="" room,="" without="" special="" air="" tightness="" and="" pressure-bearing="">40℃)>
Technical parameters (the values in the table below are for reference in type selection only)
四、工艺流程图Process flow diagram