Far infrared combined heat pump drying device and peanut drying method

Abstract

The present invention proposes a far-infrared combined heat pump drying device and a peanut drying method to solve the technical problems of low safety in the existing traditional sun drying of peanuts, low dehumidification efficiency in single heat pump drying, and uneven drying rate in single far-infrared radiation drying. The far-infrared combined heat pump drying device of the present invention uses a combined heating and dehumidification drying to solve the problems of slow heating rate in the early stage of peanut drying and low efficiency in the later stage of drying in single heat pump drying, and the problems of fast drying rate, high drying intensity, and difficulty in losing moisture in flowers and fruits in single far-infrared drying. It is not easy to cause microbial contamination during the drying process, is suitable for the drying processing of various heat-sensitive materials, and can recover sensible heat and latent heat in waste gas, reducing energy consumption when drying flowers and fruits. Compared with the existing hot air drying method for peanuts, the peanut drying method of the present invention shortens the drying time by 30% to 50% and reduces energy consumption by 20% to 30%.

Description

Technical Field

[0001] The invention relates to the technical field of processing of agricultural products at the production site, and in particular to a far-infrared combined heat pump drying device and a peanut drying method. Background Art

[0002] Peanuts are an important cash crop and oil crop in my country. They are rich in nutrients such as fat, protein, and minerals. They have the effects of delaying aging and anti-tumor, and are known as "longevity fruit". As my country's largest oil crop, my country's total peanut production, total consumption, and export volume are all ranked first in the world. The moisture content of peanuts is generally high when they are harvested, generally 50~60% (wet basis moisture content). In order to prevent peanuts from mildewing, oil immersion, and rancidity during transportation, storage, and processing, timely drying treatment is required at the place of origin.

[0003] The traditional method of drying peanuts is natural drying. Although it is simple to operate and does not require additional energy output, it has a long drying cycle, unstable drying state, huge drying field resource requirements, and the peanut harvest season is concentrated in August-October. The high temperature and high humidity environment is very likely to cause micro-mildew, especially Aspergillus flavus, which seriously affects the safety of peanuts. According to statistics, the loss of peanuts in my country that lose their edible value and commercial value due to mildew accounts for 10% to 20% of the total output each year. In particular, in 2017, the loss in some parts of my country was as high as more than 50%, and in serious areas it was as high as 70%, or even a total crop failure. The economic losses were extremely severe, which seriously restricted the healthy development of the peanut industry. Therefore, green, energy-saving, and efficient mechanical drying technology and equipment have always been the focus and difficulty of peanut drying research.

[0004] Heat pump drying has many advantages, such as low energy consumption, low drying temperature, wide adjustable range of drying conditions, easy control of the operation process, high product quality, and environmental friendliness. It has been widely used in the drying of heat-sensitive materials such as wood, fruits and vegetables, aquatic products, and grains. However, in the middle and late stages of heat pump drying, the mass transfer coefficient between air and dry materials becomes smaller, and it takes a long drying time and more energy to remove the moisture. The state of the air at the inlet and outlet of the drying chamber changes very little, which affects the cooling and dehumidification capacity of the evaporator, and the operating condition of the heat pump system deteriorates. Moreover, in order to maintain the stability of the drying temperature, most of the electrical energy input to the system is discharged in the form of heat energy, and the dehumidification efficiency is very low.

[0005] Far-infrared radiation technology achieves the correspondence between the radiation source spectrum and the absorption spectrum of the heated object, so that the product is heated evenly inside and outside, and no heating medium is required. It can effectively improve energy utilization and product quality while shortening the drying time. However, when drying with single far-infrared radiation, the high heating rate will cause more water to evaporate in the early stage of material drying, which is difficult to remove in time, affecting the drying rate in the later stage.

[0006] Therefore, there is an urgent need for a far-infrared combined heat pump drying device and a peanut drying method that can control drying in sections. Summary of the invention

[0007] In view of the technical problems of low safety in the existing traditional sun-drying of peanuts, low dehumidification efficiency in single heat pump drying and uneven drying rate in single far-infrared radiation drying, the present invention proposes a far-infrared combined heat pump drying device and a peanut drying method. By combining heat pump drying and far-infrared radiation drying, a variety of drying equipment are arranged in the drying device, and the drying program is adjusted according to the change of the wet basis moisture content of the peanuts in a segmented drying method. The drying speed is fast, the energy consumption is low, the drying efficiency is greatly improved, and the safety of the dried peanuts is high.

[0008] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0009] A far-infrared combined heat pump drying device comprises a box body, a heating unit, a dehumidification unit and an air circulation unit. The heating unit is installed in the box body through a material drying rack, the dehumidification unit is installed on one side of the box body and the dehumidification unit matches the heating unit, the air circulation unit passes through the heating unit and the dehumidification unit in sequence and the air circulation units are connected end to end to form a circulation path.

[0010] Furthermore, the dehumidification unit includes a dehumidification fan and an air energy heat pump, the dehumidification fan is installed at the bottom end of the material drying rack, the air energy heat pump is installed on one side of the box, the air flow circulation unit includes a centrifugal fan and an air duct, the centrifugal fan is installed above the material drying rack, one end of the air duct is connected to the air outlet of the centrifugal fan, and the other end of the air duct passes through the heating unit and the material drying rack to be divided into a first sub-duct and a second sub-duct, the first sub-duct is connected to the air inlet of the centrifugal fan, and the second sub-duct passes through the air energy heat pump and is connected to the air inlet of the centrifugal fan.

[0011] Furthermore, the heating unit includes a ceramic heating plate and a far-infrared radiation plate. The ceramic heating plate is fixed to one side of the interior of the box and is located inside the air duct. The far-infrared radiation plate is horizontally arranged on the material drying rack.

[0012] Furthermore, there are at least two ceramic heating plates, which are evenly arranged on one side of the interior of the box from top to bottom, and there are at least two far-infrared radiation plates, which are evenly installed on the material drying rack from top to bottom.

[0013] Furthermore, the material drying rack includes a material rack, a screw and an adjusting nut. The material rack is fixed in the box body, the material rack is located in the air duct, the screws are vertically arranged on both sides of the material rack, the adjusting nuts are installed on the screws, and both ends of the far-infrared radiation plate are arranged on the adjusting nuts.

[0014] Furthermore, material tray supporting angle codes are provided on the four columns of the material rack, material trays are provided on the material tray supporting angle codes, the number of material trays is the same as that of far-infrared radiation plates and the material trays are arranged in sequence below the far-infrared radiation plates, a weighing tray is provided at the bottom end of the material rack and the upper end of the weighing tray matches the material tray.

[0015] Furthermore, an automatic control unit is arranged at the upper end of the box body, and the automatic control unit includes a manual switch, an indicator light, a central controller, a weighing sensor, a temperature and humidity sensor, a far-infrared radiation plate temperature monitoring sensor and a material temperature detection sensor. The manual switch and the indicator light are arranged at the upper end of the box body and the manual switch and the indicator light are connected to the central controller. The central controller is respectively connected to the ceramic heating plate, the weighing sensor, the air energy heat pump, the temperature and humidity sensor, the far-infrared radiation plate temperature monitoring sensor and the material temperature detection sensor. The weighing sensor is located on one side of the weighing tray and the weighing sensor is connected to the weighing tray. The temperature and humidity sensor is located above the material rack and the temperature and humidity sensor is installed on the side wall of the air duct. The far-infrared radiation plate temperature monitoring sensor is arranged on the far-infrared radiation plate, and the material temperature detection sensor is arranged on the tray.

[0016] A peanut drying method, using a far-infrared combined heat pump drying device to dry peanuts, comprises the following steps:

[0017] S1, put the fresh flowers after cleaning and sorting into the feed tray, and use the central controller to set the drying process parameters;

[0018] S2. After the drying process parameters are set, the ceramic heating plate, the far infrared radiation plate and the air energy heat pump are turned on by manual switches to raise the temperature in the drying room, and the first stage of drying is carried out, and the moisture content of the peanut wet basis is reduced;

[0019] S3, the moisture content of the peanuts on a wet basis is reduced to the first threshold, the far-infrared radiation plate is turned off, the ceramic heating plate and the air energy heat pump are retained to dry the peanuts, and the second stage of drying is carried out, and the moisture content of the peanuts on a wet basis continues to decrease;

[0020] S4, the moisture content of the peanuts on a wet basis decreases to the second threshold, the ceramic heating plate and the air energy heat pump are turned off, and the far-infrared radiation plate is turned on to dry the peanuts, and the third stage of drying is performed, and the moisture content of the peanuts on a wet basis continues to decrease;

[0021] S5. The moisture content of the peanut wet basis drops to the third threshold value, the far-infrared radiation panel is turned off, and the peanut drying is completed.

[0022] Furthermore, the drying time of the first stage in step S2 is 30min~45min; the first threshold in step S3 is 40%~45%, and the drying time of the second stage is 4h~5h; the second threshold in step S4 is 20%~30%, and the actual drying time of the third stage is 6h~8h; the third threshold in step S5 is 8%~10%.

[0023] Beneficial effects of the present invention:

[0024] 1. The far-infrared combined heat pump drying device of the present invention can solve the problems of slow heating rate in the early stage of peanut drying and low efficiency in the later stage of drying in single heat pump drying. At the same time, it can also solve the problems of fast drying rate, high drying intensity and difficulty in losing moisture in peanuts in single far-infrared drying. The far-infrared combined heat pump drying device not only recovers the sensible heat in the waste steam during the heat pump drying process, but also recovers the latent heat in the waste steam, which greatly reduces energy consumption and improves the efficiency of heat pump drying. At the same time, the heat pump drying temperature is low and suitable for drying heat-sensitive materials. In the later stage of drying, far-infrared radiation heating drying can give full play to the advantages of fast far-infrared heating drying speed and high production efficiency. This not only solves the problem of low drying temperature and long drying time in the heat pump drying process that is easy to cause microbial contamination, but also can be applied to the drying processing of various heat-sensitive materials.

[0025] 3. Compared with the existing hot air drying method for peanuts, the peanut drying method of the present invention shortens the drying time by 30% to 50% and reduces the energy consumption by 20% to 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a schematic diagram of the structure of Example 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of the material drying rack structure of Example 1 of the present invention.

[0029] Figure 3 This is a schematic structural diagram of the far-infrared radiation plate of Example 1 of the present invention.

[0030] Figure 4 This is a schematic diagram of the structure of the material tray of Example 1 of the present invention.

[0031] Figure 5 This is a flow chart of the working method of embodiment 2 of the present invention.

[0032] In the figure, 1-box, 2-dehumidification fan, 3-air energy heat pump, 4-centrifugal fan, 5-air duct, 51-first branch air duct, 52-second branch air duct, 6-ceramic heating plate, 7-infrared radiation plate, 8-material rack, 9-screw, 10-adjusting nut, 11-material tray support angle code, 12-material tray, 13-weighing tray, 14-manual switch, 15-indicator light, 16-central controller, 17-weighing sensor, 18-temperature and humidity sensor, 19-far-infrared radiation plate temperature monitoring sensor, 20-material temperature detection sensor. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Embodiment 1, a far infrared combined heat pump drying device, such as Figure 1 As shown, it includes a box body 1, a heating unit, a dehumidification unit and an air circulation unit. The heating unit is installed in the box body 1 through the material drying rack. The dehumidification unit is installed on one side of the box body 1 and the dehumidification unit matches the heating unit. The air circulation unit passes through the heating unit and the dehumidification unit in sequence and the air circulation unit forms a circulation path. Peanuts are placed on the material drying rack. The heating unit can provide far-infrared radiation to heat and dry the flowers and fruits. The dehumidification unit can provide a heat pump to dry the flowers and fruits. The dehumidification unit can also provide a blowing dehumidification method to remove the moisture discharged from the flowers and fruits. The air circulation unit provides airflow to circulate on the heating unit, the dehumidification unit and the material drying rack to accelerate air flow and provide heating, dehumidification and drying efficiency.

[0035] It is worth noting that, in the present embodiment, the far-infrared combined heat pump drying device is illustrated by drying peanuts. In other embodiments of the present invention, the drying device can also be used to dry other flowers and fruits that need to be dried, as long as the purpose of the present invention is achieved.

[0036] Specifically, Figure 1As shown, the dehumidification unit includes a dehumidification fan 2 and an air energy heat pump 3, the dehumidification fan 2 is installed at the bottom end of the material drying rack, the air energy heat pump 3 is installed on one side of the box body 1, and the air flow circulation unit includes a centrifugal fan 4 and an air duct 5, the centrifugal fan 4 is installed above the material drying rack, one end of the air duct 5 is connected to the air outlet of the centrifugal fan 4, and the other end of the air duct 5 passes through the heating unit and the material drying rack to be divided into a first sub-air duct 51 and a second sub-air duct 52, the first sub-air duct 51 is connected to the air inlet of the centrifugal fan 4, and the second sub-air duct 52 passes through the air energy heat pump 3 and is connected to the air inlet of the centrifugal fan 4. In this embodiment, the heating unit heats the peanuts on the material drying rack, the wet basis moisture content of the peanuts is reduced, the moisture is discharged, the dehumidification fan 2 discharges the moisture in the air out of the box 1, the centrifugal fan 4 directs the airflow through the air duct 5 into the material drying rack, the air containing moisture on the material drying rack is blown into the air energy heat pump 3, the air energy heat pump 3 heats and evaporates the moisture in the air, and the heated air in the air energy heat pump 3 is blown into the air duct 5 through the centrifugal fan 4 and enters the material drying rack to heat, dehumidify and dry the peanuts.

[0037] It is worth noting that, in this embodiment, a condenser is provided inside the air energy heat pump 3, and the condenser can condense the water vapor in the air energy heat pump 3 into water for discharge, further enhancing the dehumidification and drying effect. In other embodiments of the present invention, other structures can be provided to replace the air energy heat pump 3, as long as the purpose of the present invention is achieved.

[0038] Further, such as Figure 1 As shown, the heating unit includes a ceramic heating plate 6 and a far-infrared radiation plate 7. The ceramic heating plate 6 is fixed on one side of the interior of the box 1 and is located inside the air duct 5. The far-infrared radiation plate 7 is horizontally arranged on the material drying rack. The ceramic heating plate 6 provides heat, and the airflow in the air duct 5 brings the heat into the material drying rack to heat, dehumidify and dry the peanuts. The far-infrared radiation plate 7 performs far-infrared radiation drying on the peanuts.

[0039] Specifically, Figure 1 As shown, in this embodiment, the number of ceramic heating plates 6 is 6, and the heating plates 6 are evenly arranged on one side of the interior of the box body 1 from top to bottom, and the number of far-infrared radiation plates 7 is 7, and the far-infrared radiation plates 7 are evenly installed on the material drying rack from top to bottom. In other embodiments of the present invention, the ceramic heating plates 6 and the far-infrared radiation plates 7 can be set to other numbers as long as the purpose of the present invention is achieved.

[0040] It is worth noting that, in the present embodiment, the length of the ceramic heating plate 6 is 700 mm, and the width increases from top to bottom with 50 mm as the base point and 10 mm as the interval, and the spacing between the ceramic heating plates 6 is 160 mm. In this way, while ensuring the heating effect, the ceramic heating plate 6 can also disturb the airflow in the air duct 5, so that the airflow flows evenly, increasing the heating, dehumidification and drying effect. In other embodiments of the present invention, heating plates made of other materials can be used instead of the ceramic heating plate 6 or ceramic heating plates 6 of other sizes can be used as needed, as long as the purpose of the present invention is achieved.

[0041] It is worth noting that, in the present embodiment, the far-infrared radiation plate 7 is made of carbon fiber. In other embodiments of the present invention, other materials such as carbon crystal materials may be used to make the far-infrared radiation plate 7, as long as the purpose of the present invention is achieved.

[0042] Further, such as Figure 1 and Figure 2 As shown, the material drying rack includes a material rack 8, a screw rod 9 and an adjusting nut 10. The material rack 8 is fixed in the box body 1, and the material rack 8 is located in the air duct 5. The screw rods 9 are vertically arranged on both sides of the material rack 8, and the adjusting nut 10 is installed on the screw rod 9. Both ends of the far-infrared radiation plate 7 are arranged on the adjusting nut 10. The four columns of the material rack 8 are provided with material tray support angle codes 11, and the material tray 12 is arranged on the material tray support angle code 11. The number of material trays 12 is the same as that of the far-infrared radiation plate 7, and the material trays 12 are arranged in sequence below the far-infrared radiation plate 7. A weighing tray 13 is provided at the bottom end of the material rack 8, and the upper end of the weighing tray 13 matches the material tray 12. When drying and dehumidifying peanuts, the position of the adjusting nut 10 on the screw 9 is adjusted as needed to make the distance between the feed tray 12 and the far-infrared radiation plate 7 at a suitable position. The far-infrared radiation plate 7 performs far-infrared radiation drying on the peanuts in the feed tray 12, and the weighing tray 13 measures the weight of the peanuts in the feed tray 12. The change in the moisture content of the peanuts is calculated based on the weight of the peanuts before drying.

[0043] Further, such as Figure 1 As shown, an automatic control unit is arranged at the upper end of the box body 1, and the automatic control unit includes a manual switch 14, an indicator light 15, a central controller 16, a weighing sensor 17, a temperature and humidity sensor 18, a far-infrared radiation plate temperature monitoring sensor 19 and a material temperature detection sensor 20. The manual switch 14 and the indicator light 15 are arranged at the upper end of the box body 1 and the manual switch 14 and the indicator light 15 are respectively connected to the central controller 16, as shown in FIG. Figure 3 and Figure 4As shown, the central controller is connected to the ceramic heating plate 6, the weighing sensor 17, the temperature and humidity sensor 18, the far-infrared radiation plate temperature monitoring sensor 19 and the material temperature detection sensor 20 respectively. The weighing sensor 17 is located on one side of the weighing tray 13 and is connected to the weighing tray 13. The temperature and humidity sensor 18 is located above the material rack 8 and installed on the side wall of the air duct 5. The far-infrared radiation plate temperature monitoring sensor 19 is arranged on the far-infrared radiation plate 7, and the material temperature detection sensor 20 is arranged on the material tray 12. The manual switch 14 is used to control the on and off of the ceramic heating plate 6, the far-infrared heat radiation plate 7 and the air energy heat pump 3. The indicator light 15 is used to indicate the on and off of each manual switch 14. The central controller 16 is used to receive the change value of the peanut weight transmitted by the weighing sensor 17, the change value of the temperature and humidity around the material drying rack transmitted by the temperature and humidity sensor 18, the change value of the temperature around the far-infrared radiation plate 7 transmitted by the far-infrared radiation plate temperature monitoring sensor 19, and the change value of the temperature around the material tray 12 transmitted by the material temperature detection sensor 20.

[0044] It is worth noting that in this embodiment, the ceramic heating plate 6 is built with a temperature sensor, which transmits the temperature change value of the ceramic heating plate 6 to the central controller. In other embodiments of the present invention, adaptive adjustments can also be made according to the material and structure of the ceramic heating plate 6, as long as the purpose of the present invention is achieved.

[0045] Example 2, a peanut drying method, using the far-infrared combined heat pump drying device in Example 1 to heat and dehumidify the peanuts, such as Figure 5 As shown, the following steps are included:

[0046] S1. Put the fresh peanuts after cleaning and sorting into the feed tray 12, and use the central controller 16 to set the drying process parameters; specifically, rinse the freshly harvested fresh peanuts with clean water, with a wet basis moisture content of 50%, mainly remove the sand on the peanut shells, then put them into the drying tray, and place them in the external environment for 45 minutes to remove the surface moisture of the peanut shells, and then place the peanuts in the feed tray 12, set the peanut drying process parameters on the touch screen of the central controller 16, and set 3 drying stages, wherein, in the first stage, the ceramic heating plate 6, the far infrared radiation plate 7 and the air energy heat pump 3 are all working, the drying temperatures of the three are all set to 40°C, and the wind speed of the centrifugal fan 4 is set to 1.5 m / s; in the second stage, the ceramic heating plate 6 and the air energy heat pump 3 are working, the drying temperatures are all set to 40°C, and the wind speed of the centrifugal fan 4 is set to 2.0 m / s; in the third stage, the far infrared radiation plate 7 is working, the drying temperature is set to 50°C, and the wind speed of the centrifugal fan 4 is set to 1.0 m / s.

[0047] S2. After the drying process parameters are set, the ceramic heating plate 6, the far-infrared radiation plate 7 and the air energy heat pump 3 are turned on by the manual switch 14 to increase the temperature in the drying chamber, and the first stage of drying is carried out to reduce the moisture content of the peanut wet basis; specifically, the ceramic heating plate 6, the far-infrared radiation plate 7 and the air energy heat pump 3 start working, the temperature rises to 40° C., and the drying time is 30 minutes.

[0048] S3, when the wet basis moisture content of the peanuts decreases to the first threshold value, the far-infrared radiation plate 7 is turned off, and the ceramic heating plate 6 and the air energy heat pump 3 are retained to dry the peanuts, and the second stage of drying is carried out, and the wet basis moisture content of the peanuts continues to decrease; specifically, the change value of the wet basis moisture content of the peanuts is obtained by the weight change of the peanuts transmitted by the weighing sensor 17. When the wet basis moisture content of the peanuts decreases to 40%, the far-infrared radiation plate 7 is turned off, and the ceramic heating plate 6 and the air energy heat pump 3 continue to work to dry the peanuts for 5 hours.

[0049] S4, when the wet basis moisture content of the peanuts decreases to the second threshold value, the ceramic heating plate 6 and the air energy heat pump 3 are turned off, and the far infrared radiation plate 7 is turned on to dry the peanuts, and the third stage of drying is carried out, and the wet basis moisture content of the peanuts continues to decrease; specifically, when the wet basis moisture content of the peanuts decreases to 20%, the ceramic heating plate 6 and the air energy heat pump 3 are turned off, and the far infrared radiation plate 7 is turned on to continue drying the peanuts for 6 hours.

[0050] S5, when the moisture content of the peanut wet basis drops to the third threshold, the far-infrared radiation plate 7 is turned off, and the peanut drying is completed; specifically, when the moisture content of the peanut wet basis drops to 10%, the drying device is turned off, and the peanut drying is completed.

[0051] In this embodiment, a staged peanut heating and dehumidification drying process is used. The far-infrared combined heat pump drying device not only recovers the sensible heat in the waste steam flowing in the circulation pipeline during the heat pump drying process, but also recovers the latent heat in the waste steam, which greatly reduces energy consumption and improves the efficiency of heat pump drying. At the same time, the heat pump drying temperature is low and suitable for drying heat-sensitive materials. In the later stage of drying, the far-infrared radiation heating drying can give full play to the advantages of fast far-infrared heating drying speed and high production efficiency. This not only solves the problem of low drying temperature and long drying time in the heat pump drying process that is easy to cause microbial contamination, but also can be applied to the drying processing of various heat-sensitive materials.

[0052] Embodiment 3, a peanut drying method, the difference between this embodiment and embodiment 2 is that, in this embodiment, in step S1, the initial wet basis moisture content of the peanuts is 55%, the peanuts are placed in the external environment for 60 min, the drying temperatures of the ceramic heating plate 6, the far infrared radiation plate 7 and the air energy heat pump 3 in the first stage of the peanut drying process parameters are all set to 45°C, and the wind speed of the centrifugal fan 4 is set to 3.0 m / s, in the second stage, the heat pump drying temperatures of the ceramic heating plate 6 and the air energy heat pump 3 are all set to 45°C, and the wind speed of the centrifugal fan 4 is set to 5.0 m / s, in the third stage, the drying temperature of the far infrared radiation plate 7 is set to 55°C, and the wind speed of the centrifugal fan 4 is 2.0 m / s; in step S2, the drying time of the first stage is 45min; in step S3, the first threshold is 45%, and the drying time of the second stage is 4h; in step S4, the second threshold is 25%, and the drying time of the third stage is 8h; in step S5. The third threshold is 8%.

[0053] It is worth noting that in other embodiments of the present invention, the above data can be adaptively adjusted according to the initial moisture content of the peanut wet basis and the drying time, as long as the purpose of the present invention is achieved.

[0054] The other steps in this embodiment are the same as those in Embodiment 2 and will not be described again.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A peanut drying method, using a far-infrared combined heat pump drying device to dry peanuts, characterized in that: The far-infrared combined heat pump drying device comprises a box (1), a heating unit, a dehumidification unit and an air circulation unit, wherein the heating unit is installed in the box (1) through a material drying rack, the dehumidification unit is installed on one side of the box (1) and the dehumidification unit matches the heating unit, the air circulation unit passes through the heating unit and the dehumidification unit in sequence, and the air circulation units are connected end to end to form a circulation path; The dehumidification unit comprises a dehumidification fan (2) and an air energy heat pump (3), wherein the dehumidification fan (2) is installed at the bottom end of the material drying rack, and the air energy heat pump (3) is installed on one side of the box body (1); The heating unit comprises a ceramic heating plate (6) and a far-infrared radiation plate (7), wherein the ceramic heating plate (6) is fixed to one side of the interior of the box (1) and the ceramic heating plate (6) is located inside the air duct (5) of the air circulation unit, and the far-infrared radiation plate (7) is horizontally arranged on the material drying rack; An automatic control unit is disposed at the upper end of the box body (1), the automatic control unit comprising a manual switch (14) and a central controller (16), the manual switch (14) being connected to the central controller (16); The following steps are involved: S1, putting the washed and sorted fresh peanuts into a material tray (12) on a material drying rack, and using a central controller (16) to set drying process parameters; S2, after the drying process parameters are set, the ceramic heating plate (6), the far infrared radiation plate (7) and the air energy heat pump (3) are turned on by means of a manual switch (14), so that the temperature in the drying chamber is raised, and the first stage of drying is performed, so that the moisture content of the peanuts on a wet basis is reduced; S3, the moisture content of the peanuts on a wet basis decreases to a first threshold value, the far-infrared radiation plate (7) is turned off, the ceramic heating plate (6) and the air energy heat pump (3) are retained to dry the peanuts, and the second stage of drying is performed, and the moisture content of the peanuts on a wet basis continues to decrease; S4, the moisture content of the peanuts on a wet basis decreases to a second threshold value, the ceramic heating plate (6) and the air energy heat pump (3) are turned off, and the far infrared radiation plate (7) is turned on to dry the peanuts, and the third stage of drying is performed, and the moisture content of the peanuts on a wet basis continues to decrease; S5, the moisture content of the peanuts is reduced to the third threshold value, the far-infrared radiation plate (7) is turned off, and the peanuts are dried.

2. The peanut drying method according to claim 1, characterized in that: The air circulation unit comprises a centrifugal fan (4) and an air duct (5); the centrifugal fan (4) is installed above the material drying rack; one end of the air duct (5) is connected to the air outlet of the centrifugal fan (4); the other end of the air duct (5) passes through the heating unit and the material drying rack to be divided into a first sub-air duct (51) and a second sub-air duct (52); the first sub-air duct (51) is connected to the air inlet of the centrifugal fan (4); and the second sub-air duct (52) passes through the air energy heat pump (3) and is connected to the air inlet of the centrifugal fan (4).

3. The peanut drying method according to claim 1 or 2, characterized in that: The number of the ceramic heating plates (6) is at least two, and the ceramic heating plates (6) are evenly arranged from top to bottom on one side of the interior of the box body (1); the number of the far-infrared radiation plates (7) is at least two, and the far-infrared radiation plates (7) are evenly installed from top to bottom on the material drying machine frame.

4. The peanut drying method according to claim 3, characterized in that: The material drying machine frame comprises a material rack (8), a screw rod (9) and an adjusting nut (10); the material rack (8) is fixed in a box body (1); the material rack (8) is located in an air duct (5); the screw rod (9) is vertically arranged on both sides of the material rack (8); the adjusting nut (10) is mounted on the screw rod (9); and both ends of the far-infrared radiation plate (7) are arranged on the adjusting nut (10).

5. The peanut drying method according to claim 4, characterized in that: The four uprights of the material rack (8) are provided with material tray support angle brackets (11), and the material trays (12) are provided on the material tray support angle brackets (11). The number of the material trays (12) is the same as that of the far-infrared radiation plates (7), and the material trays (12) are arranged in sequence below the far-infrared radiation plates (7). A weighing tray (13) is provided at the bottom end of the material rack (8), and the upper end of the weighing tray (13) matches the material tray (12).

6. The peanut drying method according to any one of claims 1, 2, 4 and 5, characterized in that: The automatic control unit further comprises an indicator light (15), a weighing sensor (17), a temperature and humidity sensor (18), a far-infrared radiation plate temperature monitoring sensor (19), and a material temperature detection sensor (20); the manual switch (14) and the indicator light (15) are arranged at the upper end of the box body (1), and the indicator light (15) is connected to a central controller (16), which is respectively connected to the ceramic heating plate (6), the weighing sensor (17), the air energy heat pump (3), the temperature and humidity sensor (18), the far-infrared radiation plate temperature monitoring sensor (19), and the material temperature detection sensor (20). The monitoring sensor (19) is connected to the material temperature detection sensor (20), the weighing sensor (17) is located on one side of the weighing tray (13) and the weighing sensor (17) is connected to the weighing tray (13), the temperature and humidity sensor (18) is located above the material rack (8) and the temperature and humidity sensor (18) is installed on the side wall of the air duct (5), the far-infrared radiation plate temperature monitoring sensor (19) is arranged on the far-infrared radiation plate (7), and the material temperature detection sensor (20) is arranged on the material tray (12).

7. The peanut drying method according to claim 1, characterized in that: The drying time of the first stage in step S2 is 30 min to 45 min; the first threshold in step S3 is 40% to 45%, and the drying time of the second stage is 4 h to 5 h; the second threshold in step S4 is 20% to 30%, and the drying time of the third stage is 6 h to 8 h; the third threshold in step S5 is 8% to 10%.

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