Material drying method and system, and readable storage medium

Abstract

The present disclosure relates to the field of material drying, and provides a material drying method and system, and a readable storage medium, used to ensure the drying quality of a material. The material drying method comprises the following steps: in a preheating mode, closing a fresh air flow path and a moisture discharge flow path of a material drying device, and connecting a hot air flow path of the material drying device, so as to preheat a drum of the material drying device; when the temperatures of all regions of the preheated drum reach a set value, and incoming material is detected, adjusting the material drying device to a material head mode; when a continuous duration of the material head mode reaches T_Sb, or the highest water content of the dried material output in the material head mode is higher than a minimum water content A_min% of a set dried material, adjusting the material drying device to a production mode; and, after the production mode is finished, adjusting the material drying device to a material tail mode. The described technical solution reduces aroma loss of a product, and the dried material produced thereby has good sensory quality, good water content uniformity, and a high raw material utilization rate.

Description

Material drying method, system and readable storage medium

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present disclosure is based on and claims priority to an application with CN application number 202410050588.5 and filing date January 12, 2024. The disclosure of the CN application is hereby incorporated into the present disclosure as a whole. Technical Field

[0003] The present disclosure relates to the field of material drying, and in particular to a material drying method, system, and readable storage medium. Background Art

[0004] Drying technology has a long history of application. In the fields of food, herbal medicine, and tobacco processing, material drying is a critical process. The accuracy and uniformity of moisture content after drying are particularly important, directly impacting product quality stability, energy conservation, emission reduction, and consumption reduction.

[0005] The drum of a material drying system is a rotary device used to dry materials. Traditional drying equipment uses a conveyor system to deliver the material into the drum, where it is dried as it spirals through the drum. The heat energy supply for the drying process consists of two components. The first is to heat the drum wall through steam injected into the drum pipes, which in turn heats the material and dehydrates it. The drum wall temperature is essentially consistent from the feed end to the discharge end, and this temperature is regulated by adjusting the injected steam pressure. The second component is to use process hot air to provide auxiliary heating for the material and remove any water vapor that evaporates from the material, achieving the drying effect.

[0006] The main control parameters for drying equipment include material flow, steam pressure, hot air temperature, hot air blower frequency, and dehumidification damper opening. Existing material drying equipment uses a control method that sets these parameters based on the processing intensity requirements of different materials. These parameters are adjusted to ensure that the moisture content of different materials meets the process requirements, thus completing the drying equipment's process mission.

[0007] The inventors found that the relevant technology has at least the following problems: the existing material drying method easily causes the loss of material aroma during the processing process, and is not conducive to improving the poor sensory quality caused by impurities and irritation. The sensory quality of the product is difficult to control, the material crushing rate is high and the filling capacity is low, and the moisture content of the material after drying is poorly uniform. Summary of the Invention

[0008] The present disclosure provides a material drying method, system, and readable storage medium to provide the drying quality of the material.

[0009] The present disclosure provides a material drying method, comprising the following steps:

[0010] In the preheating mode, the fresh air flow path and exhaust flow path of the material drying equipment are closed, and the hot air flow path of the material drying equipment is opened to preheat the drum of the material drying equipment; wherein, the drum is divided into a preheating temperature rising zone, an isothermal drying zone, a moisture adjustment zone, and a thermal insulation balance zone;

[0011] After the temperature of each area of ​​the drum reaches the set value after preheating, and after the incoming material is detected, the material drying equipment is adjusted to the material head mode;

[0012] When the duration of the material head mode reaches T sb Or the maximum moisture content of the dried material output in the material head mode is higher than the set minimum moisture content A of the dried material min %, then adjust the material drying equipment to production mode;

[0013] After the production mode is finished, the material drying equipment is adjusted to the tail mode.

[0014] In some embodiments, the temperature of the preheating zone of the drum in the preheating mode is lower than the temperature of the preheating zone of the drum in the head mode, the production mode, and the tail mode.

[0015] In some embodiments, the temperature of the isothermal drying zone of the drum in the preheating mode is lower than the temperature of the isothermal drying zone of the drum in the head mode, the production mode, and the tail mode.

[0016] In some embodiments, the temperature of the moisture adjustment zone of the drum in the preheating mode is lower than the temperature of the moisture adjustment zone of the drum in the head mode, the production mode, and the tail mode.

[0017] In some embodiments, the temperature of the cooling and shaping zone of the drum in the preheating mode is lower than the temperature of the cooling and shaping zone of the drum in the head mode, the production mode, and the tail mode.

[0018] In some embodiments, in production mode, the temperature of the preheating zone is t 1-3 ±Δt 1-3 The wall temperature of the isothermal drying zone is t 2-3 ±Δt 2-3 The wall temperature of the moisture adjustment zone is t 3-3 ±Δt 3-3 The temperature of the cooling and shaping zone is t4-3 ±Δt 4-3 ;The ambient temperature is t0; where t0≤t1≤t2≥t3≥t4≥t0.

[0019] In some embodiments, in the preheating mode, the fresh air valve of the fresh air flow path is closed, the dehumidification fan of the exhaust flow path is closed, and the dehumidification air valve of the exhaust flow path is closed.

[0020] In some embodiments, in the production mode, the openings of the exhaust air valve of the exhaust flow path and the fresh air valve of the fresh air flow path are both 100%, the air volume of the exhaust flow path is achieved by adjusting the operating frequency of the exhaust fan, and the air volume of the fresh air flow path is achieved by adjusting the opening of the fresh air valve, and the opening of the return air valve of the material drying equipment is 0%; or, in the production mode, the openings of the exhaust air valve of the exhaust flow path and the fresh air valve of the fresh air flow path are both 100%, and the opening of the return air valve of the material drying equipment is 0%.

[0021] In some embodiments, in the tail mode, the opening of the exhaust air valve of the exhaust circuit is smaller than the opening of the exhaust air valve of the exhaust circuit in the production mode; and / or, in the tail mode, the frequency of the exhaust fan of the exhaust circuit is smaller than the operating frequency of the exhaust fan of the exhaust circuit in the production mode; and / or, in the tail mode, the opening of the fresh air valve of the fresh air flow path is smaller than the opening of the fresh air valve of the fresh air flow path in the production mode; and / or, in the tail mode, the opening of the return air valve of the material drying equipment is larger than the opening of the return air valve in the production mode.

[0022] In some embodiments, when a material detection device provided on the conveying device detects a material-free signal, the material drying equipment is adjusted from a production mode to a material tail mode; wherein the conveying device is located upstream of the material drying equipment.

[0023] In some embodiments, after the tail mode, the method further includes the following step: adjusting the material drying equipment from the tail mode to the shutdown mode.

[0024] In some embodiments, when the material detection devices on the upstream and downstream conveying devices of the material drying equipment detect a no-material signal after a set delay time, the material drying equipment is adjusted from the end-of-material mode to the shutdown mode.

[0025] In some embodiments, when the exhaust air temperature T out If the temperature of the cylinder wall in the preheating zone, the isothermal drying zone, the moisture adjustment zone and the thermal insulation balance zone is less than or equal to the set temperature, the material drying equipment will be shut down and stop running.

[0026] In some embodiments, in the shutdown mode, the return air valve of the material drying equipment, the heater of the hot air flow path, and the heating component outside the drum are all closed.

[0027] In some embodiments, in the production mode, when the relative humidity of the exhaust air is greater than the set relative humidity RH of the exhaust air, out +ΔRH out , then increase the hot air volume Q hot-3 When the relative humidity of the exhaust air is less than the set relative humidity RH out -ΔRH out , then reduce the hot air volume Q hot-3 .

[0028] In some embodiments, in the production mode, if the moisture content of the material output after the drum drying is greater than the set moisture content of the material after drying A% + ΔA%, the hot air volume Q is increased. hot-3 And / or increase the drum wall temperature t in the moisture adjustment zone 3-3 If the moisture content of the material output after the drum drying is less than the set moisture content of the material after drying A%-ΔA%, then reduce the hot air volume Q hot-3 And / or lower the drum wall temperature t in the moisture adjustment zone 3-3 .

[0029] In some embodiments, in the production mode, if the moisture content of the material output after the drum drying is greater than the set moisture content of the material after drying A%+ΔA%, the following steps are performed:

[0030] Increase the cylinder wall temperature t in the moisture adjustment area 3-3 ;

[0031] If the wall temperature of the moisture adjustment zone t 3-3 Increase to t 3-3 +Δt 3-3 If the moisture content of the material after the drum drying is still greater than the set moisture content of the material after drying A% + ΔA%, then increase the hot air volume Q hot-3 .

[0032] In some embodiments, in the production mode, if the moisture content of the material output after the drum drying is less than the set moisture content of the material after drying A%-ΔA%, the following steps are performed to adjust the moisture content:

[0033] Lower the cylinder wall temperature t in the moisture adjustment area 3-3 ;

[0034] If the wall temperature of the moisture adjustment zone t 3-3 Lower to t3-3 -Δt 3-3 If the moisture content of the material after the drum drying is still less than the set moisture content of the material after drying A%-ΔA%, the hot air volume Q is reduced. hot-3 .

[0035] In some embodiments, in the production mode, when the temperature of the material after drying is greater than t out +Δt out When the air volume Q is increased, out-3 , thereby adjusting the natural wind volume Q new ; When the material temperature after drying is less than t out -Δt out When the exhaust air volume Q is reduced out-3 , thereby reducing the natural wind volume Q new .

[0036] In some embodiments, in the production mode, the exhaust air volume Q is always maintained. out Equal to hot air volume Q hot Plus the natural wind volume Q new , that is, Q out =Q hot +Q new .

[0037] In some embodiments, the headstock mode, the production mode, and the tailstock mode each include the following operations:

[0038] Detecting the moisture content of the material output after the drum drying;

[0039] If the moisture content of the material detected is greater than the set maximum moisture content of the material after drying A max % or less than the set minimum moisture content A of the material after drying min %, then the material will be discarded.

[0040] The present disclosure also provides a material drying system, comprising:

[0041] Memory; and

[0042] A processor coupled to the memory, wherein the processor is configured to execute the material drying method provided by any technical solution of the present disclosure based on instructions stored in the memory.

[0043] An embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the material drying method provided by any technical solution of the present disclosure.

[0044] The material drying method provided by the above technical solution can control the moisture content of the material more accurately, and completely eliminates the problems of aroma loss of the product, poor moisture content uniformity, poor filling capacity and waste of raw materials caused by the indifferent setting of the drum wall temperature of the material drying equipment in the related technology. It improves the sensory quality of the product, enhances the stability of product quality, improves the filling capacity of the product, and reduces raw material loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of this application. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the drawings:

[0046] FIG1 is a schematic structural diagram of a material drying device for implementing the material drying method provided in an embodiment of the present disclosure.

[0047] FIG2 is a schematic diagram of a hot air flow path and a tidal exhaust flow path of a material drying device for implementing the material drying method provided in an embodiment of the present disclosure.

[0048] FIG3 is a schematic diagram of a material drying method according to an embodiment of the present disclosure.

[0049] Reference numerals: 1. drum; 11. preheating zone; 111. first temperature sensor; 12. isothermal drying zone; 121. second temperature sensor; 13. moisture adjustment zone; 131. third temperature sensor; 14. heat preservation balance zone; 141. fourth temperature sensor; 2. hot air flow path; 3. bracket; 4. drum drive system; 5. temperature meter; 6. moisture meter; 7. conveying device; 71. rejecting device; 8. unloading hood; 81. unloading port; 9. exhaust flow path; 8', cooling and setting zone; 10. feeding hood; 15. fresh air flow path; hot air flow path 2 includes: 21. hot air blower; 22. heater; 23. counter-flow hot air valve; 24. downstream hot air valve; 25. fresh air valve; 26. return air valve; 27. hot air temperature meter; The exhaust flow path 9 includes: 91, exhaust fan; 92, exhaust gas humidity meter; 93, exhaust gas temperature meter; 94, exhaust air valve; 95, downstream exhaust valve; 96, upstream exhaust valve; A direction is the flow direction of exhaust gas (mixed gas of process hot air and natural air); B direction is the flow direction of process hot air; C direction is the flow direction of the material after drying. DETAILED DESCRIPTION

[0050] The technical solutions provided by the present disclosure are described in more detail below with reference to Figures 1 to 3. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​described in these embodiments should be interpreted as being merely exemplary and not limiting.

[0051] The terms "first," "second," and similar terms used in this disclosure do not denote any order, quantity, or importance, but are simply used to distinguish one part from another. Terms such as "include" or "comprise" mean that the elements preceding the term include the elements listed after the term, and do not exclude the possibility of also including other elements.

[0052] In the present disclosure, when a specific device is described as being located between a first device and a second device, an intervening device may or may not be present between the specific device and the first device or the second device. When a specific device is described as being connected to another device, the specific device may be directly connected to the other device without an intervening device, or may be not directly connected to the other device but with an intervening device.

[0053] All terms (including technical or scientific terms) used in this disclosure have the same meaning as those understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in, for example, general dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined herein.

[0054] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0055] The dimensions of the various parts shown in the drawings are not drawn in accordance with actual proportions. In the drawings, common structural elements or structural elements of the same type are given the same reference numerals, and their repeated descriptions are appropriately omitted.

[0056] The inventors have found through research that:

[0057] (1) The main reason for the loss of aroma of materials during the processing is that after the traditional drying process technology, the temperature difference between the material and the drum wall is large, and the material heating rate is too high, which causes the cytoplasmic fluid to expand rapidly, causing the cell wall to rupture and the loss of soluble substances, thereby causing the loss of product aroma and reducing the sensory quality of the product.

[0058] (2) The main reasons for the high material crushing rate and low filling capacity are: the material is dried at the same high drying temperature throughout the entire drying process, and the material is heated at high temperature for a long time in the drum 1, which reduces the material's processing resistance and causes crushing in subsequent processing. In addition, after the material is sent from the discharge end of the drum 1 to the subsequent conveying device, the temperature difference between the material and the natural environment is large, and the material encounters cold air with a too high cooling rate, resulting in crushing, thereby affecting the material's filling capacity and raw material utilization.

[0059] (3) The main reasons for the poor uniformity of the moisture content of the dried material are: when the moisture content of the dried material is too high or too low, the first method is to adjust the wall temperature of the drum. This method requires adjusting the temperature of the entire drum. Due to the large thermal inertia of the drum and the low temperature adjustment sensitivity, the moisture content of the dried material is poorly uniform, which affects the overall processing strength of the material and causes fluctuations in the sensory quality of the product; the second method is to adjust the hot air volume significantly. This method changes the residence time of the material in the drum, affects the drying time of the material in the drum, and makes the moisture content uniformity of the dried material worse and / or the chemical reaction of the material is not sufficient, and the dried material is "dry outside and wet inside". In addition, after the dried material enters the conveying device, during the natural cooling process on the conveying device, the outer layer of the material in direct contact with the ambient air has a higher cooling rate and a lower moisture content, while the inner layer of the material has a lower cooling rate and a higher moisture content.

[0060] Through creative work, the inventors have proposed the following technical solution, which can reduce the loss of material aroma during processing, have a low material crushing rate and high filling capacity, have good uniformity of material moisture content after drying, and better control of product sensory quality.

[0061] To facilitate description of the material drying method provided by the embodiments of the present disclosure, the material drying equipment for implementing the method will be first described. Referring to Figures 1 and 2 , the material drying equipment is specifically, for example, a drum dryer, comprising a feed hood 10, a drum 1, a discharge hood 8, a hot air flow path 2, a fresh air flow path 15, an exhaust flow path 9, a conveying device 7, and a rejecting device 71.

[0062] The drum 1 is provided with a feed port and a discharge port. The drum 1 is mounted on a bracket 3 and is driven by a drum drive system 4 to rotate around its central axis. The outer partitions of the drum 1 are wrapped with heating components (not shown in the figure), and the heating components in each area can be fixedly connected to the drum 1 so as to rotate synchronously with the drum 1. Alternatively, the heating components in each area can also be fixed, with a certain distance from the outer wall of the drum 1, and the heating components do not rotate with the drum 1. Alternatively, the heating components in some areas outside the drum 1 can rotate with the drum 1, while the remaining heating components do not rotate with the drum 1. In some embodiments described below, along the axial direction of the drum 1, along the direction from the feed port to the discharge port of the drum 1, the drum 1 is divided into four areas: a preheating zone 11, an isothermal drying zone 12, a moisture adjustment zone 13, and a thermal insulation balance zone 14. The temperature of the heating components separately arranged outside each area is independently controlled to achieve precise regional control of the temperature of the drum wall 1. The heating components are, for example, electromagnetic coils.

[0063] The feed cover 10 is arranged at the feed port of the drum 1 , and the discharge cover 8 is arranged at the discharge port of the drum 1 .

[0064] The hot air flow path 2 includes a hot air blower 21, a heater 22, a hot air temperature meter 27, a downstream hot air valve 24, a downstream exhaust valve 95, a reverse hot air valve 23, and a reverse exhaust valve 96. The hot air flow path is connected to the interior of the drum 1, and the hot air flow path 2 is used to transport process hot air to the interior of the drum 1. Specifically, a hot air pipe (not shown) can be provided to transport process hot air. The hot air pipe runs through the interior of the drum 1, and the length direction of the hot air pipe is basically along the axial direction of the drum 1. A hot air baffle is provided in the middle position of the hot air pipe, and an opening is provided on the wall of the hot air pipe. Hot air can flow in from the port at either end of the hot air pipe, and then flow out from the opening in the wall of the hot air pipe into the interior of the drum 1. The hot air entering the interior of the drum 1 can come into contact with the material to achieve heat exchange and dehumidification.

[0065] Exhaust flow path 9 communicates with the interior of drum 1 and is used to exhaust exhaust gas from drum 1. Generally, exhaust flow path 9 communicates with discharge hood 8 and / or feed hood 10. Exhaust flow path 9 includes a dehumidification fan 91, an exhaust gas humidity meter 92, an exhaust gas temperature meter 93, and a dehumidification air valve 94.

[0066] The interior of the discharge cover 8 is a cooling and shaping area 8'. A discharge port 81 is provided at the lower portion of the discharge cover 8, through which the material naturally falls to the conveying device 7 by gravity.

[0067] The downstream of the material drying equipment is provided with a conveying device 7 and a rejecting device 71 thereon. Above the conveying device 7 is provided a temperature meter 5 and a moisture meter 6 to detect the temperature and moisture content of the dried material in real time.

[0068] The materials used in the present disclosure are sheet-shaped, filament-shaped, and thin rod-shaped materials. In some embodiments below, tobacco is used as an example.

[0069] Before introducing the technical solutions of the embodiments of the present disclosure, the parameters of the material drying equipment and the process requirements for materials entering the material drying equipment are first introduced.

[0070] Once the material drying equipment model is selected, the length and diameter of the drum 1 are known. Based on these parameters, the cross-sectional area and other parameters of the drum 1 can be calculated, thereby setting the material flow rate. The inclination angle of the drum 1 from the feed end to the discharge end is adjustable from 2° to 6°. The drying time of the material in the drum 1 is adjusted by the inclination angle and rotation speed of the drum 1.

[0071] Process parameter requirements include, but are not limited to, the following: material flow rate of the drying equipment, material inlet moisture content, material outlet moisture content, material inlet temperature, material outlet temperature, material drying time, and the physical and sensory qualities of the dried material. For a specific model of drying equipment, the specific numerical ranges for these process requirements will be determined by the process technology department based on the type of material being processed.

[0072] The material drying method provided in the embodiment of the present disclosure mainly controls the temperature, hot air volume and moisture exhaust air volume of each area of ​​the drum 1.

[0073] Table 1. Drum wall temperature in various zones and modes

[0074] Table 2. Hot air parameters and moisture exhaust air parameters of material drying equipment in various modes

[0075] In the above Table 1, in the preheating mode, the head mode, the production mode, and the tail mode, the temperatures of the preheating zone 11, the isothermal drying zone 12, the moisture adjustment zone 13, and the thermal insulation balance zone 14 are all range values. According to the process parameters in each mode, and the temperature values ​​obtained by the detection, the temperature of each area of ​​the drum 1 can be adjusted in real time so that it is within the range specified in the above table, and adjusted in time within the specified range according to the target moisture content of the material. In the above Table 2, in the shutdown mode, it is necessary to lower the temperature of the preheating zone 11, the isothermal drying zone 12, the moisture adjustment zone 13, and the thermal insulation balance zone 14. The cooling efficiency can be improved by turning the hot air volume to the maximum, turning off the heater 22 to reduce the hot air temperature, and adjusting the moisture exhaust air volume to be greater than or equal to the hot air volume.

[0076] Table 3. Material setting parameters

[0077] Table 4. Status of material drying equipment in each mode

[0078] It should be noted that due to table size limitations, Table 4 shows one possible flow path for the preheating mode. In practice, material drying equipment can employ other preheating flow paths. The following text details the three flow path configurations for the preheating mode. In Table 4, the openings of the fresh air valve, return air valve, moisture exhaust valve, downstream hot air valve, and downstream exhaust valve affect airflow resistance; a larger opening reduces resistance.

[0079] The parameters in this article are defined as follows: the cylinder wall temperature of the preheating zone 11 is t1±Δt1, the cylinder wall temperature of the isothermal drying zone 12 is t2±Δt2, the cylinder wall temperature of the moisture adjustment zone 13 is t3±Δt3, and the cylinder wall temperature of the heat preservation balance zone 14 is t4±Δt4. The cooling and shaping zone corresponds to the dried material, and the temperature of the dried material is set to t out ±Δt out .

[0080] t2 is the main drying temperature required by the process, determined by the process technology department. Assuming the ambient temperature is t0, then t0 ≤ t1 ≤ t2 ≥ t3 ≥ t4 ≥ t0. Table 1 shows that the temperature range for t4 is always greater than the ambient temperature t0. Therefore, preheating the material in the lower-temperature preheating zone 11 reduces or even prevents excessive heating rates after entering drum 1, which can reduce product sensory quality. This better preserves the material's aroma and improves drying quality. Excessive heating rates can cause rapid expansion of the cytoplasmic fluid, rupturing cell walls and leading to the loss of soluble substances.

[0081] The temperature setting value t2 of the isothermal drying zone 12 is the main dehydration and chemical reaction process of the material. In this area, the material dehydration rate is the highest and the chemical reaction rate such as the Maillard reaction is the fastest. Its temperature setting directly affects the moisture content of the processed material and the sensory quality of the final product.

[0082] The moisture adjustment zone 13 is a feedback adjustment zone for the moisture content of the dried material. The material has completed most of the dehydration and chemical reaction in the first two stages. The dehydration rate and chemical reaction rate of the material in the moisture adjustment zone 13 are already relatively slow. Small-scale temperature adjustment has little effect on the dehydration rate and chemical reaction rate of the material. In order to reduce or even avoid the deterioration of the physical properties of the material under continuous high-temperature drying, the temperature t3 in this area is set to be lower than the cylinder wall temperature t2 of the isothermal drying zone 12 to avoid excessive drying of the material and the generation of a burnt smell.

[0083] The heat-insulating balance zone 14 makes the moisture content and chemical reaction progress of the material more uniform. The cylinder wall temperature t4 in this area is lower than or equal to the cylinder wall temperature t3 in the moisture adjustment zone 13, reducing or even preventing the continuous rise in the temperature of the material, further ensuring the physical properties of the material, optimizing the material's processing resistance, and balancing the moisture content of the material, making the temperature and moisture content of each part of the material more uniform.

[0084] In the cooling and shaping area 8', the dried material is pre-cooled in the discharge hood by a mixture of process hot air and cold air, thereby reducing or even avoiding the problem of the material being crushed due to the excessive cooling rate of the cold air after being sent from the discharge port 81 of the drum 1 to the conveying device 7, and reducing or even avoiding the problem of poor cooling uniformity of the material on the conveying device (the cooling rate of the outer layer material in direct contact with the ambient air is faster, while the cooling rate of the inner layer material is slower), thereby improving the cooling uniformity.

[0085] The preheating zone 11 is equipped with a first temperature sensor 111 for collecting the temperature therein. The isothermal drying zone 12 is equipped with a second temperature sensor 121 for collecting the temperature therein. The moisture adjustment zone 13 is equipped with a third temperature sensor 131 for collecting the temperature therein. The heat-maintaining balance zone 14 is equipped with a fourth temperature sensor 141 for collecting the temperature therein. The temperature of each zone of the drum 1 is collected and controlled independently. The temperature of the material after cooling and setting is collected in real time by a temperature meter 5.

[0086] In each mode described later, the first temperature sensor 111 detects the cylinder wall temperature of the preheating zone 11 in real time. When the cylinder wall temperature is higher than the set value, the power of the heating component in the corresponding area outside the cylinder wall is reduced; when the cylinder wall temperature is lower than the set value, the power of the heating component in the corresponding area outside the cylinder wall is increased.

[0087] In each mode described later, the second temperature sensor 121 detects the wall temperature of the isothermal drying zone 12 in real time: when the wall temperature is higher than the set value, the power of the heating component in the corresponding area outside the wall is reduced; when the wall temperature is lower than the set value, the power of the heating component in the corresponding area outside the wall is increased.

[0088] In each mode described later, the third temperature sensor 131 detects the cylinder wall temperature of the moisture adjustment zone 13 in real time: when the cylinder wall temperature is higher than the set value, the power of the heating component in the corresponding area outside the cylinder wall is reduced; when the cylinder wall temperature is lower than the set value, the power of the heating component in the corresponding area outside the cylinder wall is increased.

[0089] In each mode described later, the fourth temperature sensor 141 detects the cylinder wall temperature of the insulation balance zone 14 in real time: when the cylinder wall temperature is higher than the set value, the power of the heating component in the corresponding area outside the cylinder wall is reduced; when the cylinder wall temperature is lower than the set value, the power of the heating component in the corresponding area outside the cylinder wall is increased.

[0090] In each mode described below, the hot air temperature meter 27 detects the hot air temperature in real time: when the hot air temperature is higher than the set value, the power of the heater 22 is reduced; when the hot air temperature is lower than the set value, the power of the heater 22 is increased.

[0091] In various embodiments, the hot air volume is adjusted by adjusting the frequency of the hot air blower 21 : the hot air volume is increased by increasing the operating frequency of the hot air blower 21 , and the hot air volume is decreased by decreasing the operating frequency of the hot air blower 21 .

[0092] In various embodiments, the exhaust air volume is adjusted by adjusting the frequency of the exhaust fan 91. The exhaust air volume is increased by increasing the operating frequency of the exhaust fan 91, and the exhaust air volume is reduced by decreasing the operating frequency of the exhaust fan 91.

[0093] The exhaust air temperature is detected by the exhaust gas temperature meter 93, and the hot air temperature is detected by the hot air temperature meter 27.

[0094] In some embodiments, the hot air volume is Q hot ±ΔQ hot , hot air temperature is T ha ±ΔT ha , the dehumidification air volume is Q out ±ΔQ out , the temperature of the exhaust wind is T out 、Natural wind volume is Q new ±ΔQ new .

[0095] Dehumidification air volume Q out Equal to hot air volume Q hot Plus the natural wind volume Q new , that is, Q out =Q hot +Q new .

[0096] Set relative humidity RH of dehumidifying air out ±ΔRH out , set the moisture content of the material after drying A% ± ΔA%, set the maximum moisture content of the material after drying A max %, set the minimum moisture content of the material after drying A mit %. Set the temperature of the material after drying to t out ±Δt out .

[0097] The present disclosure provides a material drying method that can be applied to the processing of food, herbs, tobacco, and other materials. The material drying method includes the following steps:

[0098] Step S1, in the preheating mode, close the fresh air flow path and the exhaust flow path of the material drying equipment, and open the hot air flow path of the material drying equipment to preheat the drum 1 of the material drying equipment; wherein the drum 1 is divided into a preheating temperature rising zone 11, an isothermal drying zone 12, a moisture adjustment zone 13 and a thermal insulation balance zone 14.

[0099] In some embodiments, in the preheating mode, the fresh air valve 25 of the fresh air flow path 15 is closed, and the dehumidification fan 91 and the dehumidification valve 94 of the dehumidification flow path 9 are closed. The hot air is preheated by internal circulation in the drum 1, which has a higher preheating efficiency.

[0100] There are several ways to configure the airflow in preheat mode: The first option is to turn off the exhaust fan 91, exhaust air valve 94, fresh air valve 25, downstream hot air valve 24, and downstream exhaust valve 95, and open the hot air blower 21, heater 22, return air valve 26, reverse hot air valve 23, and reverse exhaust valve 96. The second option is to turn off the exhaust fan 91, exhaust air valve 94, fresh air valve 25, reverse hot air valve 23, and reverse exhaust valve 96, and open the hot air blower 21, heater 22, return air valve 26, downstream hot air valve 24, and downstream exhaust valve 95. The third option is to turn off the exhaust fan 91, exhaust air valve 94, and fresh air valve 25, and open the hot air blower 21, heater 22, return air valve 26, downstream hot air valve 24, downstream exhaust valve 95, reverse hot air valve 23, and reverse exhaust valve 96.

[0101] The purpose of the preheating mode is to raise the temperature of each area of ​​the drum 1 to a set value. The technical solution of the embodiment of the present disclosure adopts the method of circulating hot air inside the drum 1 without exhausting moisture or introducing fresh air, so the preheating efficiency is higher and the preheating operation is more energy-saving.

[0102] After step S1, the drum wall temperatures in the four zones within drum 1 and the hot air temperature within drum 1 rise to their respective set temperature ranges for preheat mode and are maintained there until the drum enters head mode. In preheat mode, the temperature ranges for preheat zone 11, isothermal drying zone 12, moisture adjustment zone 13, and thermal equilibrium zone 14 are as shown in the example ranges in the first row of Table 1: 100±1°C for preheat zone 11, 110±1°C for isothermal drying zone 12, 100±1°C for moisture adjustment zone 13, and 95±1°C for thermal equilibrium zone 14.

[0103] In step S2, after the temperatures of all zones of drum 1 reach the set values ​​in preheating mode and incoming material is detected, the material drying equipment is switched to feed mode. Whether incoming material has been detected is determined by the following method: a conveyor device is provided upstream of the material drying equipment, and the conveyor device is equipped with a detection device. When the detection device detects a material presence signal, it indicates that material has been received.

[0104] In step S2, in the feed mode, see Table 4. The dehumidification fan 91 is opened and its frequency is gradually increased; the fresh air valve 25 is opened and its opening is gradually increased; and the dehumidification valve 94 is opened and its opening is gradually increased. It is not necessary to open it to 100%. Because the amount of material in the drum 1 is very small in the feed mode, the material has low requirements on the dehydration capacity of the material drying equipment. Therefore, the frequency of the fresh air valve 25, dehumidification valve 94, and dehumidification fan 91 does not need to be set to a very high level.

[0105] Step S3: When the material head mode lasts for T sb Or the maximum moisture content of the dried material output in the material head mode is higher than the set minimum moisture content of the dried material A min %, then adjust the material drying equipment to production mode.

[0106] The control logic from preheating mode to feed mode and then to production mode is as follows: the material drying equipment is preheated to meet the feeding conditions and waits for the production line to feed the material. When the material begins to enter drum 1, the material drying equipment adjusts to the parameters of the feed mode and continuously and stably feeds the material to drum 1. When the material enters drum 1 and reaches the feed mode, the time T sb Or the moisture meter 6 detects that the maximum moisture content of the material after drying is greater than the minimum moisture content A min %, slowly increase the operating frequency of the dehumidification fan 91 and the opening of the dehumidification air valve 94 and the fresh air valve 25, and simultaneously reduce the opening of the return air valve 26, and then enter the production mode.

[0107] Continuing to refer to Table 4, in normal production mode, the fresh air valve is open at 100%, the exhaust air valve is open at 100%, the exhaust air volume is controlled by adjusting the operating frequency of the exhaust fan, and the return air valve is closed, i.e., the opening is 0%. Alternatively, in production mode, the exhaust air valve of the exhaust flow path and the fresh air valve of the fresh air flow path are both open at 100%, the air volume of the exhaust flow path is achieved by adjusting the operating frequency of the exhaust fan, the air volume of the fresh air flow path is achieved by adjusting the opening of the fresh air valve, and the opening of the return air valve of the material drying equipment is 0%. The material drying equipment can adopt countercurrent mode, downstream mode, or mixed flow mode. If the downstream mode is used to dry the material, the downstream hot air valve is open at 100%, the downstream exhaust valve is open at 100%, the countercurrent hot air valve is open at 0%, and the countercurrent exhaust valve is open at 0%. If the countercurrent mode is used to dry the material, the downstream hot air valve opening is 0%, the downstream exhaust valve opening is 0%, the countercurrent hot air valve opening is 100%, and the countercurrent exhaust valve opening is 100%. If the mixed flow mode is used to dry the material, the downstream hot air valve opening is 100%, the downstream exhaust valve opening is 100%, the countercurrent hot air valve opening is 100%, and the countercurrent exhaust valve opening is 100%.

[0108] In the production mode, the waste gas containing water vapor evaporated from the material is discharged out of the equipment through the exhaust path 9, while the hot air heated by the heater 22 is completely dry fresh air, which increases the relative humidity of the process hot air, thereby increasing the dehydration rate of the material and improving the drying capacity of the equipment.

[0109] In production mode, the temperature of the preheating zone 11 is t 1-3 ±Δt 1-3 , the wall temperature of the isothermal drying zone 12 is t 2-3 ±Δt 2-3 , the wall temperature of the moisture adjustment zone 13 is t 3-3 ±Δt 3-3 , the temperature of the insulation balance zone 14 is t 4-3 ±Δt 4-3 ;The ambient temperature is t0; where t0≤t1≤t2≥t3≥t4≥t0.

[0110] In production mode, the drying process of the material in the four zones of the drum 1 is as follows: the material first enters the preheating zone 11, and the drum wall temperature of the preheating zone 11 is t 1-3 ±Δt 1-3 , so that the material and the moisture in the material are heated up, preparing for the rapid dehydration of the material; then, the material enters the isothermal drying zone 12, where the wall temperature of the isothermal drying zone 12 is t 2-3 ±Δt 2-3 In the isothermal drying zone 12, the material is kept at a constant temperature and rapidly dehydrated, and a more intense chemical reaction is carried out; then, the material enters the moisture adjustment zone 13, and the wall temperature of the moisture adjustment zone 13 is t3-3 ±Δt 3-3 In the moisture adjustment zone 13, the material continues to be dehydrated, but the dehydration rate and chemical reaction rate of the material in this zone are significantly reduced. The wall temperature of this zone is controlled by the feedback of the moisture content of the material after drying. Then, the material enters the heat preservation balance zone 14, and the wall temperature of the heat preservation balance zone 14 is t 4-3 ±Δt 4-3 . In the thermal insulation balance zone 14, the temperature of the material no longer rises, reducing or even avoiding the large temperature difference between the material and the environment that causes crushing, and the continuous high-temperature drying of the material that reduces the processing resistance. The thermal insulation balance zone 14 can balance the temperature and moisture content between the materials, making the temperature and moisture content between each part of the material more uniform. Finally, the material enters the cooling and shaping zone 8' in the discharge hood 8. In the discharge hood 8, the material encounters the natural wind head-on during the free fall process to enhance heat exchange, so that the material is preliminarily cooled before entering the natural environment, and is shaped during the cooling process, thereby improving the material filling capacity, and reducing or even avoiding the increase in material crushing due to the excessive cooling rate after the dried material enters the conveying device 7.

[0111] In production mode, (t 4-3 ±Δt 4-3 )≤(t 3-3 ±Δt 3-3 ), that is, the temperature of the heat-insulating equilibrium zone t4 is always below the temperature t3 of the moisture-adjusting zone 13, ensuring that the material temperature in the heat-insulating equilibrium zone 14 remains constant or rises only slightly. The material then freely falls within the discharge hood 8 onto the conveyor 7, where it encounters the natural wind directly during free fall, further enhancing the cooling effect. This allows the material to cool slowly during the continuous dehydration process, reducing the cooling rate and minimizing material fragmentation, further improving the uniformity of the moisture content and cooling of the dried material.

[0112] Of the various modes, production mode lasts the longest, and the drying effect of the material is also largely determined by the production mode. In production mode, it is necessary to monitor the temperature, moisture content, and relative humidity of the exhaust air of the dried material in real time to control the drying effect.

[0113] In production mode, when the relative humidity of the exhaust air is greater than the set relative humidity RH out +ΔRH out , then increase the operating frequency of the hot air blower 22 and increase the hot air volume Q hot-3 ; When the relative humidity of the exhaust air is lower than the set relative humidity RH out -ΔRH out , then reduce the operating frequency of the hot air blower 22 and reduce the hot air volume Q hot-3 Whether increasing or decreasing the hot air volume, it is necessary to always maintain the dehumidification air volume Q outEqual to hot air volume Q hot Plus the natural wind volume Q new , that is, Q out =Q hot +Q new .

[0114] The relative humidity of the exhaust air affects the dehydration rate of the material in drum 1. When the relative humidity of the exhaust air is high, the dehydration rate is low. In this case, the hot air volume is increased to reduce the relative humidity of the hot air in drum 1 to prevent a decrease in the dehydration rate. When the relative humidity of the exhaust air is low, the opposite occurs, maintaining a relatively stable dehydration rate.

[0115] In production mode, if the moisture content of the material output after drying by drum 1 is greater than the set moisture content of the material after drying A% + ΔA%, the hot air volume Q is increased. hot-3 And / or increase the wall temperature t of the moisture adjustment zone 13 3-3 If the moisture content of the material output after drying by drum 1 is less than the set moisture content of the material after drying A%-ΔA%, reduce the hot air volume Q hot-3 and / or reduce the wall temperature t of the moisture adjustment zone 13 3-3 . Ultimately, the moisture content of the adjusted material is within the required range.

[0116] In production mode, a moisture meter 6 is used to measure the moisture content of the material conveyed by the conveying device 7 in real time. The material is dried. The specific steps for adjusting the moisture content of the material are as follows:

[0117] The first case: In the production mode, if the moisture content of the material output after drying by the drum 1 is greater than the set moisture content of the material after drying A% + ΔA%, then adjust according to the following steps: increase the drum wall temperature t 3-3 If the water conditioning zone 13 of the cylinder wall temperature t 3-3 Increase to t 3-3 +Δt 3-3 If the moisture content of the material after drying by drum 1 is still greater than the set moisture content of the material after drying A% + ΔA%, the hot air volume Q is increased. hot- 3.

[0118] In the second case, in the production mode, if the moisture content of the material output after drying by the drum 1 is less than the set moisture content of the material after drying A%-ΔA%, the following steps are followed to adjust: reduce the drum wall temperature t 3-3 If the water conditioning zone 13 of the cylinder wall temperature t 3-3 Reduce to t 3-3 -Δt 3-3If the moisture content of the material after drying by drum 1 is still less than the set moisture content of the material after drying A%-ΔA%, the hot air volume Q is reduced. hot-3 .

[0119] The first and second cases above both adopt two-stage regulation: the first stage regulation is to adjust the wall temperature t of the drum 1 in the moisture regulation area 13 in real time according to the moisture content of the dried material detected by the moisture meter 6. 3-3 When the moisture content of the material after drying is greater than A%+ΔA%, the wall temperature t is increased by increasing the power of the heating component outside the area. 3-3 When the moisture content of the dried material is lower than A%-ΔA%, the wall temperature t is lowered by reducing the power of the heating component outside the area. 3-3 When adjusting the wall temperature of the moisture adjustment zone 13, always keep t 2-3 ≥t 3-3 ≥t 4-3 .

[0120] Since most of the water in the material has evaporated after being dried and dehydrated in the preheating zone 11 and the isothermal drying zone 12, the moisture content of the material is relatively low. At this time, the material enters the moisture adjustment zone 13, and the cylinder wall temperature t 3-3 Fluctuations in the temperature have little impact on the sensory quality of the material. Furthermore, the moisture adjustment zone 13 is located close to the moisture content detection location for the dried material, and the subsequent heat-insulating balancing zone 14 balances the temperature and moisture content of the material. Using this first-stage adjustment helps ensure the stability of the product's sensory quality and improves the stability and sensitivity of moisture content control for the dried material.

[0121] If the moisture content of the material still does not meet the requirements after the first level adjustment, the second level adjustment is adopted: when the wall temperature t 3-3 to t 3-3 +Δt 3-3 If the moisture content of the material after drying is still higher than A%+ΔA%, increase the hot air volume Q hot-3 When the water regulating zone 13 wall temperature t is lowered 3-3 to t 3-3 -Δt 3-3 If the moisture content of the material after drying is still lower than A%-ΔA%, reduce the hot air volume Q hot-3 Whether increasing or decreasing the hot air volume, it is necessary to always maintain the dehumidification air volume Q out Equal to hot air volume Q hot Plus the natural wind volume Q new , that is, Q out =Q hot +Q new .

[0122] The temperature meter 5 detects the temperature of the dried material after being processed by the material drying equipment in real time. In the production mode, the method of adjusting the material temperature is as follows: in the production mode, when the temperature of the dried material is greater than t out +Δt out When the air volume Q is increased, out-3 , thereby adjusting the natural wind, that is, the fresh air volume Q new ; When the material temperature after drying is less than t out -Δt out When the exhaust air volume Q is reduced out-3 , thereby reducing the natural wind or fresh air volume Q new Whether increasing or decreasing the exhaust air volume, it is necessary to always keep the exhaust air volume Q out Equal to hot air volume Q hot Plus the natural wind volume Q new , that is, Q out =Q hot +Q new .

[0123] In production mode, whether it is to adjust the temperature of the material or the moisture content of the material, as long as it involves the adjustment of the dehumidification air volume or the hot air volume, it is necessary to always keep the dehumidification air volume Q out Equal to hot air volume Q hot Plus the natural wind volume Q new , that is, Q out =Q hot +Q new .

[0124] The temperature of the material after drying is affected by the cooling effect of the cooling and shaping zone 8'. When the material temperature is too high, it indicates that the cooling effect of the cooling and shaping zone 8' does not meet the process requirements, and the natural wind volume Q used for cooling needs to be increased. new , so that the material in the cooling and shaping area 8' has more cold air to strengthen the heat exchange with it, which is achieved by increasing the moisture exhaust air volume Q out When the material temperature is low, it indicates that the cooling effect of the cooling and shaping zone 8 'exceeds the process requirements and the natural wind volume Q for cooling needs to be reduced. new , so that the material enters less cold air in the cooling and shaping area 8' to exchange heat with it, which is achieved by reducing the exhaust air volume Q out To achieve it.

[0125] Step S4: After the production mode ends, the material drying equipment is adjusted to the tail mode.

[0126] Conveyor device 7 is located upstream of the material drying equipment. When the material detection device installed on conveyor device 7 detects a material absence signal after a set delay time, the material drying equipment switches from production mode to tail-off mode: the openings of the exhaust air valve 94 and the fresh air valve 25 are slowly reduced, while the opening of the return air valve 26 is simultaneously increased. As the material flow rate gradually decreases, to ensure that the moisture content of the material at the tail-off stage is not too low, the relative humidity of the hot air is rapidly increased to reduce the dehydration rate of the material, improve the stability of the material moisture content, and thus reduce material loss.

[0127] As shown in Table 1, in the material drying method described above, the temperature of drum 1's preheating zone 11 in preheating mode is lower than that in headstock mode, production mode, and tailstock mode. The preheating mode simply raises drum 1's temperature to a temperature close to that required for headstock mode. Inside drum 1, the material first passes through preheating zone 11, then through isothermal drying zone 12, then through moisture adjustment zone 13, and finally through thermal equilibrium zone 14.

[0128] Continuing to refer to Table 1, since the material in the drum 1 in the head mode and the tail mode is relatively small, the set temperature of any one of the four areas in the head mode and the tail mode is almost the same: that is, the set temperature of the preheating zone 11 in the head mode is the same as the set temperature of the preheating zone 11 in the tail mode, the set temperature of the isothermal drying zone 12 in the head mode is the same as the set temperature of the isothermal drying zone 12 in the tail mode, the set temperature of the moisture adjustment zone 13 in the head mode is the same as the set temperature of the moisture adjustment zone 13 in the tail mode, and the set temperature of the insulation balance zone 14 in the head mode is the same as the set temperature of the insulation balance zone 14 in the tail mode.

[0129] Based on the above set temperature, in the head mode, the amount of material in the drum 1 increases from small to large, and the drum wall temperature gradually rises from low to high to the production stage, thereby gradually increasing the dehydration capacity of the equipment; while in the tail mode, the amount of material in the drum 1 decreases from large to small, and the drum wall temperature gradually decreases from the set temperature of the production mode from high to low, thereby reducing the dehydration capacity of the equipment.

[0130] Compared to the production mode, the tail-of-material mode has a lower demand for dehumidification, a lower requirement for fresh air volume, and a higher requirement for return air volume. In the tail-of-material mode, the opening of the dehumidification air valve 94 of the dehumidification flow path 9 is smaller than that of the dehumidification air valve 94 of the dehumidification flow path in the production mode, or the operating frequency of the dehumidification fan 91 is reduced. Alternatively, in the tail-of-material mode, the frequency of the dehumidification fan 91 of the dehumidification flow path is smaller than that of the dehumidification fan 91 of the dehumidification flow path in the production mode. In the tail-of-material mode, the opening of the fresh air valve 25 of the fresh air flow path 15 is smaller than that of the fresh air valve 25 of the fresh air flow path 15 in the production mode, or the operating frequency of the hot air blower 21 is reduced. In the tail-of-material mode, the opening of the return air valve 26 of the material drying equipment is larger than that of the return air valve in the production mode.

[0131] After the above step S4, the material drying method further comprises the following steps:

[0132] Step S5: Adjust the material drying equipment from the tail mode to the shutdown mode.

[0133] When the material detection devices on the upstream and downstream conveying devices of the material drying equipment detect the material-free signal, it means that there is no more material. At this time, the material drying equipment is adjusted from the material end mode to the shutdown mode. out If the temperature is less than or equal to the set value and the cylinder wall temperature in the four zones is less than or equal to the set temperature, the equipment will shut down and stop running.

[0134] In the shutdown mode, when the exhaust air temperature T out If the temperature of the drum wall in the preheating zone 11, the isothermal drying zone 12, the moisture adjustment zone 13 and the thermal insulation balance zone 14 is less than or equal to the set temperature, the material drying equipment will be shut down and stop running.

[0135] Referring to Table 4, in the shutdown mode, the return air valve 26 of the material drying equipment, the heater 22 of the hot air flow path 2, and the heating component outside the drum 1 are all closed. Other valves are open.

[0136] In some embodiments, in the above steps S2 to S4, each step includes the following operations: detecting the moisture content of the material output after drying by the drum 1; if the moisture content of the material detected by the moisture meter 6 is greater than the set maximum moisture content A of the material after drying, max % or less than the set minimum moisture content A of the material after drying min In the material head mode, production mode, and material tail mode, as long as the moisture content of the obtained material does not meet the requirements, the material must be discarded to improve the quality of the finished product.

[0137] After drying in the material drying equipment, the material is initially cooled in the cooling and shaping area 8' within the discharge hood and then conveyed from the discharge port 81 to the conveyor device 7. While being conveyed by the conveyor device 7, the material continues to cool and shape, and a small amount of surface moisture evaporates. The material is then conveyed to the next process by the conveyor device 7. Before being conveyed to the next process, unqualified material is rejected by the rejection device 71 of the conveyor device 7.

[0138] The moisture content of the material is detected in real time by the moisture meter 6 installed above the conveying device 7. max % or less than A min %, the rejecting device 71 on the conveying device 7 is opened, and the materials with unqualified moisture content are rejected by the rejecting device. max % of the material and the moisture content is less than A min % of the material is unqualified and needs to be discarded to avoid product quality problems. The maximum moisture content of the material is A max % and the minimum moisture content of the material A min %The standards are issued by the process department.

[0139] Some specific embodiments are described below, taking a material drying device for drying A tobacco shreds as an example.

[0140] Material drying equipment parameters: drum 1 length 6000mm (including preheating zone 11 length 1150mm, isothermal drying zone 12 length 1300mm, moisture adjustment zone 13 length 1150mm, insulation balance zone 14 length 1150mm), drum 1 diameter 800mm, drum 1 inclination angle from high to low from feed end to discharge end 3°, rated air volume of hot air blower 21 2100m 3 / h. The length of the isothermal drying zone 12 is slightly longer than the respective lengths of the preheating zone 11, the moisture adjustment zone 13, and the thermal equilibrium zone 14. The lengths of the preheating zone 11, the moisture adjustment zone 13, and the thermal equilibrium zone 14 are essentially the same. In Figure 1, direction A represents the flow direction of the exhaust gas (a mixture of process hot air and natural air); direction B represents the flow direction of the process hot air; and direction C represents the flow direction of the dried material.

[0141] Process parameters: material flow rate 500kg / h, material moisture content before drying 20.0%±1.5%, material moisture content after drying 12.8%±0.5%, material temperature before drying 28±2℃, material drying time about 270s, material filling value after drying greater than 3.8cm 3 / g. Under higher temperature conditions, such as in summer, the material temperature before drying is 32±2℃, the material drying time is about 220s, and other parameters are the same as above.

[0142] Parameters of preheating mode: The wall temperature of the four zones is set to 100±1℃, 110±1℃, 100±1℃, 95±1℃ respectively, and the hot air volume is 900±100m 3 / h, hot air temperature 100±1℃, dehumidification air volume 0m 3 / h.

[0143] Parameters of the head mode: head duration is Tsb = 360s, the cylinder wall temperatures of the four zones are set to 105±2℃, 118±2℃, 105±5℃, 100±2℃, and the hot air volume is 400±100m 3 / h, hot air temperature 100±2℃, dehumidification air volume Q out-2 =550±100m 3 / h.

[0144] Parameters of production mode: The wall temperature of the four zones is set to 110±0.5℃, 128±0.5℃, 110±10℃, 105±0.5℃ respectively, and the hot air volume is 1000±100m 3 / h, hot air temperature 102±0.5℃, dehumidification air volume 1200-1800m 3 / h, relative humidity of dehumidifying air is 50±5%, moisture content of material after drying is 12.8%±0.5%, and temperature of material after drying is 45±3℃.

[0145] Parameters of the tail mode: The wall temperatures of the four zones are set to 105±2℃, 120±2℃, 105±5℃, and 100±2℃ respectively, and the hot air volume is 500±100m 3 / h, hot air temperature 100±2℃, dehumidification air volume 650±100m 3 / h.

[0146] Parameters of shutdown mode: Close the return air valve 26, heater 22 and the heating components (not shown in the figure) in the corresponding areas outside the drum wall of the preheating zone 11, isothermal drying zone 12, moisture adjustment zone 13, and thermal equilibrium zone 14 of the drum 1. All other valves are set to 100% open state. Increase the operating frequency of the dehumidification fan 91 and / or hot air blower 21. Set the dehumidification air temperature to 60°C. Set the drum wall temperature of the four zones to t 1-5 =t 2-5 =t 3-5 =t 4-5 =60℃.

[0147] The maximum moisture content of the material after drying is set to 14.5% and the minimum moisture content of the material after drying is set to 7.0%.

[0148] The production process is controlled as follows:

[0149] (1) Adjust the parameters to the preheating mode, close the dehumidification fan 91, dehumidification air valve 94, fresh air valve 25, countercurrent hot air valve 23, and countercurrent exhaust valve 96, and open the hot air fan 21, heater 22, return air valve 26, downstream hot air valve 24, and downstream exhaust valve 95.

[0150] (2) Start the production line and preheat the material drying equipment so that the drum wall temperature and hot air temperature in the four zones of drum 1 are within the parameter range of the preheating mode.

[0151] (3) After the drum dryer is preheated and meets the conditions of (2), it can be fed and started to produce. When the material starts to enter the drum 1, the parameters of the material head mode are adjusted to continuously and stably convey the material to the material drying equipment. When the material has entered the drum for 360 seconds or the moisture meter 6 detects that the moisture content of the dried material is greater than the minimum moisture content of 7.0%, the dehumidification fan 91 is started, the opening of the dehumidification air valve 94 and the fresh air valve 25 is slowly increased, and the opening of the return air valve 26 is simultaneously decreased, and then the production mode is entered.

[0152] (4) Adjust the parameters to the production mode, the opening of the dehumidification valve 94 and the fresh air valve 26 is 100%, and the opening of the return air valve 26 is 0%.

[0153] (5) The material first enters the preheating zone 11, so that the material and the moisture in the material are heated up, preparing for the rapid dehydration of the material; then, the material enters the isothermal drying zone 12, where the material is kept at a constant temperature and rapidly dehydrated, and a more intense chemical reaction is carried out; then, the material enters the moisture adjustment zone 13, where the material continues to be dehydrated, but the dehydration rate and chemical reaction rate of the material in this area are significantly reduced; then, the material enters the heat preservation balance zone 14, where the temperature of the material is no longer increased to avoid the temperature difference between the material and the environment. The material is too large and thus causes crushing, and the continuous high-temperature drying of the material reduces the processing resistance. The main function of this area is to balance the temperature and moisture content between the materials, so that the temperature and moisture content between the various parts of the material are more uniform; finally, the material enters the cooling and shaping area 8' in the discharge cover 8. In the discharge cover 8, the material encounters the natural wind head-on during the free fall process to enhance the heat exchange, so that the material is preliminarily cooled before entering the natural environment, and is shaped during the cooling process, thereby improving the material filling capacity and reducing or even avoiding the excessive cooling rate of the dried material after entering the conveying device 7, which increases the material crushing.

[0154] (6) In production mode, the exhaust gas humidity meter 92 detects the relative humidity of the exhaust air in real time. When the relative humidity of the exhaust air is greater than 50% + 5%, the operating frequency of the hot air blower 22 is increased to increase the hot air volume; when the relative humidity of the exhaust air is less than 50% - 5%, the operating frequency of the hot air blower 22 is reduced to reduce the hot air volume; so that the relative humidity of the exhaust air is always maintained in the range of 45% to 55%.

[0155] When adjusting the hot air volume, adjust the exhaust air volume synchronously to meet Q out =Q hot +Q new .

[0156] (7) In production mode, while the material is passing through the conveying device 7, the moisture meter 6 detects the moisture content of the dried material after being processed by the material drying equipment in real time. When the moisture content of the dried material is greater than 12.8% + 0.5%, the hot air volume is increased and / or the wall temperature of the moisture adjustment zone 13 is increased. When the moisture content of the dried material is less than 12.8% - 0.5%, the hot air volume is decreased and / or the wall temperature of the moisture adjustment zone 13 is decreased;

[0157] When adjusting the hot air volume, the exhaust air volume should be adjusted simultaneously to ensure that Q out =Q hot +Q new .

[0158] (8) The moisture content of the dried material is adjusted at the first level. The moisture meter 6 detects the moisture content of the dried material after processing by the material drying equipment in real time, and adjusts the wall temperature of the moisture adjustment zone 13 of the drum 1 in real time according to the moisture content of the dried material detected by the moisture meter 6. When the moisture content of the dried material is greater than 12.8% + 0.5% (13.3%), the power of the heating component of the corresponding area outside the drum wall of this area is increased to increase the wall temperature, but the wall temperature of the moisture adjustment zone 13 shall not be higher than 120°C. When the moisture content of the dried material is lower than 12.8% - 0.5% (12.3%), the power of the heating component of the corresponding area outside the drum wall of this area is reduced to lower the wall temperature, but the wall temperature of the moisture adjustment zone 13 shall not be lower than 100°C.

[0159] (9) Secondary regulation of the moisture content of the dried material. The wall temperature of the moisture regulating zone 13 is regulated through step (8). When the wall temperature is raised to 120°C, if the moisture content of the dried material is still higher than 12.8% + 0.5% (13.3%), the hot air volume is increased. When the wall temperature is lowered to 100°C, if the moisture content of the dried material is still lower than 12.8% - 0.5% (12.3%), the hot air volume is reduced, and the moisture content of the dried material is maintained within the range of 12.3% to 13.3%.

[0160] When adjusting the hot air volume, the exhaust air volume should be adjusted simultaneously to ensure that Q out =Q hot +Q new .

[0161] (10) The temperature meter 5 detects the temperature of the dried material after being processed by the material drying equipment in real time. When the temperature of the dried material is greater than 45℃+3℃, the moisture exhaust air volume is increased, thereby adjusting the natural wind volume; when the temperature of the dried material is less than 45℃-3℃, the moisture exhaust air volume is reduced, thereby reducing the natural wind volume;

[0162] When adjusting the exhaust air volume, the hot air volume should be maintained, and the natural air volume should be adjusted synchronously to ensure that Q out =Q hot +Q new .

[0163] (11) The hot air temperature meter 27 detects the hot air temperature in real time: when the hot air temperature is higher than the set value, the power of the heater 22 is reduced; when the hot air temperature is lower than the set value, the power of the heater 22 is increased. The first temperature sensor 111 detects the wall temperature of the preheating zone 11 in real time: when the wall temperature is higher than the set value, the power of the heating components of the corresponding area outside the wall of the preheating zone 11 is reduced; when the wall temperature of the preheating zone 11 is lower than the set value, the power of the heating components of the corresponding area outside the wall of the preheating zone 11 is increased. The second temperature sensor 121 detects the wall temperature of the isothermal drying zone 12 in real time: when the wall temperature of the isothermal drying zone 12 is higher than the set value, the power of the heating components of the corresponding area outside the wall of the isothermal drying zone 12 is reduced; when the wall temperature of the isothermal drying zone 12 is lower than the set value, the power of the heating components of the corresponding area outside the wall of the isothermal drying zone 12 is increased. The third temperature sensor 131 detects the wall temperature of the moisture adjustment zone 13 in real time. When the wall temperature of the moisture adjustment zone 13 is higher than a set value, the power of the heating components in the corresponding area outside the wall of the moisture adjustment zone 13 is reduced. When the wall temperature of the moisture adjustment zone 13 is lower than the set value, the power of the heating components in the corresponding area outside the wall of the moisture adjustment zone 13 is increased. The fourth temperature sensor 141 detects the wall temperature of the thermal insulation balance zone 14 in real time. When the wall temperature of the thermal insulation balance zone 14 is higher than a set value, the power of the heating components in the corresponding area outside the wall of the thermal insulation balance zone 14 is reduced. When the wall temperature of the thermal insulation balance zone 14 is lower than the set value, the power of the heating components in the corresponding area outside the wall of the thermal insulation balance zone 14 is increased.

[0164] (12) When the material detection device on the upstream conveying device of the material drying equipment detects a material-free signal, the parameters are adjusted to the material tail mode, and the operating frequency of the moisture exhaust valve 94 or the moisture exhaust fan 91 and the opening of the fresh air valve 25 are slowly reduced, and the opening of the return air valve 26 is simultaneously increased.

[0165] (13) When the material detection devices on the upstream and downstream conveying devices of the material drying equipment detect the material-free signal, the parameters are adjusted to the shutdown mode. When the exhaust air temperature is less than or equal to the set value of 60°C and the cylinder wall temperature of the four zones is less than or equal to the set temperature of 60°C, the equipment shuts down and stops running.

[0166] (14) The material dried by the material drying equipment is initially cooled in the cooling and shaping area 8' in the discharge hood and then sent to the conveying device 7 from the discharge port 81. During the conveying process through the conveying device 7, the material continues to cool and shape and evaporates a small amount of surface moisture, and is then transported to the next process through the conveying device 7.

[0167] (15) In the above steps, the material drying method also includes the removal of unqualified materials after drying. The moisture meter 6 installed above the conveying device 7 detects the moisture content of the material in real time. When the moisture content of the material is higher than 14.5% or lower than 7.0%, the rejection device 71 on the conveying device 7 is opened, and the material with unqualified moisture content is rejected by the rejection device to avoid product quality problems.

[0168] The above-mentioned technical solution provides a material drying method based on precise moisture content control. By zoning and segmenting the control parameters of the material drying equipment and performing two-stage feedback control of the target moisture content of the material after drying, it abandons the traditional extensive drying mode and achieves more precise, efficient, environmentally friendly, and high-quality material drying. The product has better sensory and physical quality and completely solves the impact of changes in ambient temperature and humidity and the temperature and humidity of the incoming materials on the drying results. Compared with the existing technology, the technical solution of the disclosed embodiment has the following advantages:

[0169] First, the temperature and moisture content of the material treated by the material drying equipment are more uniform, and the stability of temperature and moisture content is greatly improved.

[0170] Second, by preheating and precooling the materials, the excessive loss of soluble substances in the materials is avoided, which has the effect of enhancing the flavor and fragrance, and improves the material quality and sensory quality of the product.

[0171] Third, except for the main drying zone (isothermal drying zone 12), the material drying temperature is lower, so that the material maintains higher mechanical properties and processing resistance, thereby reducing material breakage, improving material utilization, and improving material elasticity.

[0172] Fourth, through pre-cooling in the cooling and shaping zone, the cooling and shaping effect of the material is better, its filling capacity is improved, the temperature difference between the material and the natural environment is reduced, and the material breakage is further reduced.

[0173] Fifth, when the moisture content of the dried material is too high or too low, a two-stage adjustment method is used. First, the wall temperature of the moisture adjustment zone 13 is adjusted, and then the hot air volume is adjusted. This method makes the material moisture content adjustment more sensitive and the control more precise.

[0174] Sixth, based on the control mode of the head and tail of the material, the head and tail stages have a higher relative humidity of the hot air, thereby reducing the dehydration rate of the material and reducing the amount of unqualified materials in the head and tail production stages.

[0175] An embodiment of the present disclosure provides a material drying system, including a memory and a processor coupled to the memory, wherein the processor is configured to execute the material drying method in any one of the aforementioned embodiments based on instructions stored in the memory.

[0176] The memory may include, for example, a system memory, a fixed non-volatile storage medium, etc. The system memory may store, for example, an operating system, application programs, a boot loader, and other programs.

[0177] Some embodiments of the present disclosure further provide a computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the material drying method of the material drying device in any of the above embodiments is implemented.

[0178] The processors described herein may include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0179] A storage medium can be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of medium. As used herein, disks and discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks often reproduce data magnetically, while discs reproduce data optically with lasers. The above combinations should also be included within the scope of computer-readable media.

[0180] Those skilled in the art will appreciate that the method embodiments of the present disclosure may be provided as methods, systems, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present disclosure may take the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0181] The present disclosure is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present disclosure. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0182] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0183] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0184] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present disclosure.

[0185] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present disclosure and not to limit it. Although the present disclosure has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present disclosure can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present disclosure, which should be included in the scope of the technical solution for protection requested by the present disclosure.

Claims

1. A method for drying materials, comprising the following steps: In the preheating mode, close the fresh air flow path and the exhaust flow path of the material drying equipment, and conduct the hot air flow path of the material drying equipment to preheat the drum (1) of the material drying equipment; wherein, the drum (1) is divided into a preheating and temperature rising zone (11), an isothermal drying zone (12), a moisture adjustment zone (13), and a heat preservation and balance zone (14); After the temperature of each area of the drum (1) reaches the set value after preheating and the incoming material is detected, adjust the material drying equipment to the head mode; When the duration of the stock head mode reaches T sb or the highest moisture content of the dried material output in the stock head mode is higher than the set minimum moisture content A of the post-dried material min %, then adjust the material drying equipment to the production mode; After the production mode ends, adjust the material drying equipment to the tail mode.

2. The method for drying materials according to claim 1, wherein in the preheating mode, the temperature of the preheating and temperature rising zone (11) of the drum (1) is lower than the temperature of the preheating and temperature rising zone (11) of the drum (1) in the head mode, production mode, and tail mode.

3. The method for drying materials according to claim 1 or 2, wherein in the preheating mode, the temperature of the isothermal drying zone (12) of the drum (1) is lower than the temperature of the isothermal drying zone (12) of the drum (1) in the head mode, production mode, and tail mode.

4. The method for drying materials according to any one of claims 1 to 3, wherein in the preheating mode, the temperature of the moisture adjustment zone (13) of the drum (1) is lower than the temperature of the moisture adjustment zone (13) of the drum (1) in the head mode, production mode, and tail mode.

5. The method for drying materials according to any one of claims 1 to 4, wherein in the preheating mode, the temperature of the heat preservation and balance zone (14) of the drum (1) is lower than the temperature of the heat preservation and balance zone (14) of the drum (1) in the head mode, production mode, and tail mode.

6. The material drying method according to any one of claims 1 to 5, wherein in the production mode, the temperature of the preheating and temperature-rising zone (11) is t 1-3 ±Δt 1-3 , the temperature of the barrel wall of the isothermal drying zone (12) is t 2-3 ±Δt 2-3 , the temperature of the barrel wall of the moisture adjustment zone (13) is t 3-3 ±Δt 3-3 , the temperature of the heat preservation and balance zone (14) is t 4-3 ±Δt 4-3 ; the ambient temperature is t0; wherein, t0 ≤ t1 ≤ t2 ≥ t3 ≥ t4 ≥ t0.

7. The method for drying materials according to any one of claims 1 to 6, wherein in the preheating mode, the fresh air valve of the fresh air flow path is closed, the exhaust fan of the exhaust flow path is closed, and the exhaust air valve of the exhaust flow path is closed.

8. The method for drying materials according to any one of claims 1 to 7, wherein in the production mode, the opening degrees of the exhaust air valve of the exhaust flow path and the fresh air valve of the fresh air flow path are both 100%, the air volume of the exhaust flow path is achieved by adjusting the operating frequency of the exhaust fan, the air volume of the fresh air flow path is achieved by adjusting the opening degree of the fresh air valve, and the opening degree of the return air valve of the material drying equipment is 0%; or, the opening degrees of the exhaust air valve of the exhaust flow path and the fresh air valve of the fresh air flow path are both 100%, and the opening degree of the return air valve of the material drying equipment is 0%.

9. The material drying method according to any one of claims 1 to 8, wherein in the tail-end mode, the opening degree of the exhaust air valve of the exhaust air flow path is smaller than that in the production mode; and / or, in the tail-end mode, the operating frequency of the exhaust air fan of the exhaust air flow path is lower than that in the production mode; and / or, in the tail-end mode, the opening degree of the fresh air valve of the fresh air flow path is smaller than that in the production mode; and / or, in the tail-end mode, the opening degree of the return air valve of the material drying equipment is larger than that in the production mode.

10. The material drying method according to any one of claims 1 to 9, wherein when the material detection device provided on the conveying device (7) detects a no-material signal and delays for a set time, the material drying equipment is adjusted from the production mode to the tail-of-material mode; wherein, The conveying device (7) is located upstream of the material drying equipment.

11. The material drying method according to any one of claims 1 to 10, wherein after the tail-end mode, the method further comprises the following steps: Adjust the material drying equipment from the tail-end mode to the shutdown mode.

12. The material drying method according to claim 11, wherein when no-material signals are detected by the material detection devices on the upstream and downstream conveying devices of the material drying equipment, the material drying equipment is adjusted from the tail-end mode to the shutdown mode.

13. The material drying method according to claim 12, wherein when the exhaust air temperature T out is less than or equal to the set value, and the wall temperatures of the preheating and warming zone (11), the isothermal drying zone (12), the moisture adjustment zone (13), and the heat preservation and balance zone (14) are all less than or equal to their respective set temperatures, the material drying equipment shuts down and stops operating.

14. The material drying method according to claim 12 or 13, wherein in the shutdown mode, the return air valve of the material drying equipment, the heater of the hot air flow path, and the heating components outside the drum (1) are all closed.

15. The material drying method according to any one of claims 1 to 14, wherein in the production mode, when the relative humidity of the moisture exhaust air is greater than the set relative humidity RH of the moisture exhaust air out +ΔRH out , the hot air volume Q is increased hot-3 ; when the relative humidity of the moisture exhaust air is less than the set relative humidity RH of the moisture exhaust air out -ΔRH out , the hot air volume Q is decreased hot-3 .

16. The material drying method according to any one of claims 1 to 15, wherein in the production mode, if the moisture content of the material output after drying by the drum (1) is greater than the set moisture content of the dried material A% + ΔA%, the hot air volume Q is increased hot-3 and / or the wall temperature t of the moisture adjustment zone (13) is increased 3-3 ; if the moisture content of the material output after drying by the drum (1) is less than the set moisture content of the dried material A% - ΔA%, the hot air volume Q is decreased hot-3 and / or the wall temperature t of the moisture adjustment zone (13) is decreased 3-3 .

17. The material drying method according to claim 5, wherein in the production mode, if the moisture content of the material output after drying by the drum (1) is greater than the set moisture content of the dried material A% + ΔA%, the adjustment is made according to the following steps: Raise the cylinder wall temperature t of the moisture regulation zone (13) 3-3 ; If the cylinder wall temperature t of the moisture adjustment zone (13) 3-3 is raised to t 3-3 +Δt 3-3 , and the moisture content of the material output after drying by the drum (1) is still greater than the set moisture content of the dried material A% + ΔA%, then increase the hot air volume Q hot-3 .

18. The material drying method according to claim 5, wherein in the production mode, if the moisture content of the material output after drying by the drum (1) is less than the set moisture content of the dried material A% - ΔA%, the adjustment is made according to the following steps: Lower the barrel wall temperature t of the moisture adjustment area (13) 3-3 ; If the barrel wall temperature t of the moisture adjustment zone (13) 3-3 is lowered to t 3-3 -Δt 3-3 , and the moisture content of the material output after drying by the drum (1) is still less than the set moisture content A%-ΔA% of the material after drying, then reduce the hot air volume Q hot-3 .

19. According to the material drying method described in any one of claims 1 to 18, wherein in the production mode, when the temperature of the dried material is greater than t out +Δt out , the exhaust air volume Q 0ut-3 is increased, so as to increase the natural air volume Q new ; when the temperature of the dried material is less than t out -Δt out , the exhaust air volume Q out-3 is decreased, so as to decrease the natural air volume Q new .

20. The material drying method according to any one of claims 5 to 8, wherein in the production mode, the moisture exhaust air volume Q is always maintained out equal to the hot air volume Q hot plus the natural air volume Q new , that is, Q out = Q hot + Q new .

21. The material drying method according to any one of claims 1 to 20, wherein each of the head-end mode, the production mode, and the tail-end mode includes the following operations: Detect the moisture content of the material output after drying by the drum (1); If the moisture content of the detected material is greater than the set maximum moisture content A of the dried material max % or less than the set minimum moisture content A of the dried material min %, then the material is rejected.

22. A material drying system, comprising: A memory; And A processor coupled to the memory, the processor being configured to execute the material drying method according to any one of claims 1 to 21 based on instructions stored in the memory.

23. A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the material drying method according to any one of claims 1 to 21.

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