A particle drainage type temperature controlled spiral pipeline continuous drying system and drying method

Abstract

The present invention discloses a particle drainage type temperature-controlled spiral pipeline continuous drying system, comprising an airflow generating device, a feeder, a vacuum drying device and a vacuum generator, wherein the vacuum drying device comprises a support assembly, a vacuum chamber, a cover plate and a spiral pipeline, wherein the bottom and top of the vacuum chamber are respectively sealed and fixedly connected to the support assembly and the cover plate, the vacuum chamber is provided with an isolated inner cavity and a vacuum cavity, the vacuum cavity is connected to a vacuum pump, the inner cavity is filled with a liquid medium, the spiral pipeline is fixedly arranged in the inner cavity and immersed in the liquid medium, and the cover plate is provided with a temperature control device for heating and controlling the temperature of the liquid medium. The present invention realizes continuous flow drying of powder materials, maintains the first-in-first-out of materials during the drying process, eliminates local siltation of materials during the drying process, eliminates the problems of over-drying and under-drying, and improves the uniformity of material drying.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical production and manufacturing, and specifically relates to a particle drainage type temperature-controlled spiral pipeline continuous drying system and a drying method. Background Art

[0002] There are three main methods for drying powder particles in the existing technology. The first is centralized drying in static ovens, which is suitable for drying thin layers of powder. However, when the powder particles are thick, drying uniformity is poor, and local over-drying or under-drying is prone to occur, and drying efficiency is low. The second is centralized fluidized bed drying, which uses pipelines to transfer hot air. Friction and transition points between the pipelines and the chamber consume a large amount of airflow heat and kinetic energy. Furthermore, the pipelines and working chamber are not insulated, resulting in severe heat dissipation and low energy efficiency. The drying equipment is also complex, bulky, and expensive. The third is continuous drying equipment, which uses gas as power and auxiliary mechanical transmission devices (such as drive belts and push screws) to fluidize the powder. This can meet the requirements of continuous drying, but it is difficult to ensure first-in, first-out drying of the materials. Parts of the material often cannot be discharged smoothly, resulting in over-drying. Energy efficiency is not significantly improved, and the equipment is complex and expensive. Summary of the Invention

[0003] The object of the present invention is to provide a particle drainage type temperature controlled spiral pipeline continuous drying system and drying method, so as to realize continuous flow drying of powder materials, maintain the first-in-first-out of materials in the drying process, eliminate local sedimentation of materials in the drying process, eliminate the problems of over-drying and under-drying, and improve the uniformity of material drying; reduce the energy loss in the process of transferring the thermal energy and kinetic energy of the power medium to the material, and improve the energy efficiency utilization rate; at the same time, simplify the dryer structure, improve the reliability of the drying device, and reduce the cost of the drying device.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A particle drainage type temperature-controlled spiral pipeline continuous drying system, comprising an airflow generating device, a feeder, a vacuum drying device and a vacuum generator, the vacuum drying device comprising a support assembly, a vacuum chamber, a cover plate and a spiral pipeline, the bottom and top of the vacuum chamber are respectively sealed and fixedly connected to the support assembly and the cover plate, the vacuum chamber is provided with an isolated inner cavity and a vacuum cavity, the vacuum cavity is connected to a vacuum pump, the inner cavity is filled with a liquid medium, the spiral pipeline is fixedly arranged in the inner cavity and immersed in the liquid medium, the cover plate is provided with a temperature control device for heating and controlling the temperature of the liquid medium, the upper end of the spiral pipeline extends out of the vacuum chamber and is fixedly connected to one end of the feeder, the other end of the feeder is fixedly connected to the airflow generating device, the lower end of the spiral pipeline extends out of the vacuum chamber and is fixedly connected to the vacuum generator, a drop pipe is fixedly arranged at the bottom of the vacuum generator, and a moisture analyzer is fixedly arranged on the side wall of the drop pipe.

[0006] Furthermore, the feeder includes a discharge barrel and a feed pipe, the discharge barrel is vertically fixedly connected to the feed pipe, and a feeding device is provided above the discharge barrel.

[0007] Furthermore, the support assembly includes an end cover and several side plates, the end cover is provided with a stepped circular inner groove, the radius of the side plate is the same as the radius of the stepped circular inner groove, the side plate is tightly attached to the stepped circular inner groove and the bottom is fixedly connected to the end cover, and a bottom sealing cover is provided in the center of the end cover.

[0008] Furthermore, the number of side panels is not less than two and not more than four, the side panels are fan-shaped annular panels, and the fan-shaped expansion angle α is between 30-50°. A group of mounting holes is opened at the bottom of each side panel, and each group of mounting holes includes two threaded holes, and the angle β between the two threaded holes ranges from 20-40°. The end cover is provided with n groups of stepped holes in the stepped circular inner groove, where n is equal to the number of side panels, and each group of stepped holes includes two stepped holes, and the angle between the two stepped holes is equal to β. The adjacent circumferential angles between adjacent groups of stepped holes are equal to β. The side plate is fixed on the end cover by countersunk bolts passing through the stepped holes and threaded holes.

[0009] Furthermore, the vacuum chamber includes a vacuum tube body, an upper flange and a lower flange, the vacuum tube body is coaxially provided with an outer tube layer and an inner tube layer, the upper and lower ends of the outer tube layer and the inner tube layer are fixedly connected to the upper flange and the lower flange respectively, the open area surrounded by the inner tube layer is the inner cavity, and the closed area surrounded by the outer tube layer, the inner tube layer, the upper flange and the lower flange is the vacuum cavity, the lower flange is fixedly connected to the end cover, a lower sealing gasket is arranged between the lower flange and the end cover, the upper flange is fixedly connected to the cover plate, an upper sealing gasket is arranged between the upper flange and the cover plate, and the upper flange is provided with a vacuum hole connected to the vacuum cavity.

[0010] Furthermore, the spiral pipeline includes a spiral tube body, which is matched and sleeved between the inner layer of the tube body and the side plate. The upper and lower ends of the spiral tube body are respectively fixedly connected with an inlet pipe and an outlet pipe. The inlet pipe and outlet pipe pass through the vacuum tube body and are sealed and fixedly connected to the vacuum tube body. The inlet pipe is fixedly connected to the feed pipe, and the outlet pipe is fixedly connected to the vacuum generator.

[0011] Furthermore, the outer diameter D of the spiral tube body O The inner diameter of the spiral tube body is the same as the inner diameter of the inner layer of the tube body. i The outer diameter of the spiral tube body is the same as that of the side plate, and the helix angle λ of the spiral tube body is between 9 and 12 degrees.

[0012] Furthermore, the temperature control device includes a heater, a thermometer, an infusion tube and a vacuum tube. The heater is fixedly arranged at the center of the cover and extends downward into the inner cavity. The thermometer and infusion tube are fixedly arranged on the cover and extend downward into the inner cavity. The vacuum tube is fixedly arranged on the cover and extends downward into the vacuum cavity through the vacuum hole. The vacuum tube is connected to the vacuum pump.

[0013] The present invention also provides a particle drainage type temperature-controlled spiral pipeline continuous drying method, comprising the following steps:

[0014] S1: Inject liquid medium into the inner cavity through the infusion tube until the spiral tube body is immersed and then stop infusion;

[0015] S2: Start the vacuum pump and draw vacuum into the vacuum chamber through the vacuum tube to maintain the vacuum degree at -2 to -10 Pa;

[0016] S3: Start the heater to heat the liquid medium and the spiral tube body to a target temperature within the range of 60-80°C. Use a thermometer to monitor the temperature change of the liquid medium in real time, and form a feedback adjustment with the heating control of the heater. With the target temperature as the benchmark, the temperature deviation is controlled to ±1°C.

[0017] S4: Start the airflow generating device and adjust the airflow heating temperature and airflow velocity, start the vacuum generator, and form a dry and clean airflow with a certain amount of thermal energy and kinetic energy that flows from the airflow generating device through the feeder and the spiral pipeline to the vacuum generator;

[0018] S5: The feeding device is turned on, and the wet particles enter the feeding pipe through the feeding barrel and flow into the spiral tube body under the action of the airflow formed in step 4), and at the same time, heat transfer occurs between the airflow and the spiral tube body to perform dehydration and drying;

[0019] S6: The particles dried in step S5 are sucked into the vacuum generator and fall into the drop pipe. At the same time, the moisture analyzer detects the absorbance integral area of ​​the near-infrared spectrum in the sensitive band in real time, and determines the moisture content through the established detection model. The moisture content is then compared with the target moisture content to determine whether the moisture content is qualified, thus completing the particle drying process.

[0020] Furthermore, the construction of the detection model includes the following steps:

[0021] S1: According to the difference between the air flow heating temperature T1 and the liquid medium heating temperature T2, the following nine combination modes are listed: combination 1: T1 equals 60℃, T2 equals 60℃, combination 2: T1 equals 60℃, T2 equals 70℃, combination 3: T1 equals 60℃, T2 equals 80℃, combination 4: T1 equals 70℃, T2 equals 60℃, combination 5: T1 equals 70℃, T2 equals 70℃, combination 6: T1 equals 70℃, T2 equals 80℃, combination 7: T1 equals 80℃, T2 equals 60℃, combination 8: T1 equals 80℃, T2 equals 70℃, combination 9: T1 equals 80℃, T2 equals 80℃;

[0022] S2: For the granular material with an initial moisture content of ω0, first use a moisture analyzer to detect the absorbance integral area of ​​its near-infrared spectrum in the sensitive band, record it as F0, and then use an externally calibrated KF Karl Fischer moisture meter to detect its moisture content value, record it as E0;

[0023] S3: The granular material with an initial moisture content of ω0 in step S2 is dried using the nine combinations of step S1 to obtain nine materials in a dry state, which are used as standard materials for modeling. The absorbance integral areas of the nine standard granular materials in the sensitive band are detected by a moisture analyzer, and recorded as F1, F2, F3, F4, F5, F6, F7, F8, and F9, respectively. The moisture content values ​​of the nine standard granular materials are then detected by a KF Karl Fischer moisture analyzer, and recorded as E1, E2, E3, E4, E5, E6, E7, E8, and E9, respectively.

[0024] S4: Draw a graph of the absorbance integral area-water content function, i.e., a water content detection model graph.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention is provided with an air flow generating device, a vacuum drying device, a temperature control device and a vacuum generator, so as to realize continuous flow drying of powder materials, maintain the first-in-first-out of materials in the drying process, eliminate local sedimentation of materials in the drying process, eliminate the problems of over-drying and insufficient drying, and improve the drying uniformity of materials; and through the flexible control of the five variables of the drainage air flow temperature, the drainage air flow velocity, the liquid medium temperature, the absorption pressure of the vacuum generator, and the structural parameters of the spiral tube body, it can meet the drying requirements of different types of materials, materials with different humidity, and materials with different volatility characteristics, and has the ability to flexibly control heat transfer for wet particles with different initial moisture contents and different moisture volatilization effects, so as to obtain the best drying effect.

[0027] (2) The energy efficiency utilization rate of the drying system of the present invention has achieved a high effect. The dissipation of heat energy is eliminated by the vacuum insulation layer. Through the vertical height design, the gravitational potential energy is cleverly used to reduce the energy loss in the process of transferring the thermal energy and kinetic energy of the power medium to the material, reduce the kinetic energy demand for the air flow generating device and the vacuum generator, and improve the energy efficiency utilization rate.

[0028] (3) The present invention realizes real-time detection of the moisture content of the particles at the drop pipe by setting up a moisture analyzer and constructing a moisture content detection model.

[0029] (4) The present invention has a simple and reliable structure, and is easy to install, disassemble and maintain. It successfully realizes the flow drying of wet particles of materials, can meet the needs of continuous production, and can be applied to the pharmaceutical, food, chemical and other industries for volatilization and separation of moisture and solvent contained in powder materials, intermediate particles and finished particles. Through the continuous drying effect of the present invention, the powder materials can reach the moisture or solvent content range required by the process design standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic three-dimensional diagram of the structure of the present invention;

[0031] Figure 2 This is the main view of the present invention;

[0032] Figure 3 A top view of the present invention;

[0033] Figure 4 for Figure 3 Middle AA section view;

[0034] Figure 5 Schematic diagram of the feeder structure;

[0035] Figure 6 Schematic diagram of the vacuum drying device structure (vacuum chamber hidden);

[0036] Figure 7Schematic diagram of the support assembly structure;

[0037] Figure 8 It is the top view of the side panel;

[0038] Figure 9 This is a top view of the end cover (with two side panels installed);

[0039] Figure 10 This is a top view of the end cover (with four side panels installed);

[0040] Figure 11 This is a cross-sectional view of the vacuum chamber;

[0041] Figure 12 It is a schematic diagram of the spiral pipeline structure;

[0042] Figure 13 Schematic diagram of the temperature control device structure;

[0043] Figure 14 This is the detection spectrum of the moisture analyzer;

[0044] Figure 15 It is the relationship diagram of absorbance integrated area-water content function;

[0045] Figure 16 It is a real-time curve chart of moisture content test results;

[0046] The markings in the accompanying drawings are: 1-airflow generating device, 2-feeder, 201-discharging barrel, 202-feeding pipe, 3-vacuum drying device, 4-support assembly, 401-end cover, 401A-stepped circular inner groove, 401B-stepped hole, 402-side plate, 402A-threaded hole, 403-bottom sealing cover, 5-vacuum chamber, 501-vacuum tube body, 502-tube outer layer, 503-tube inner layer, 504-inner cavity, 50 5-vacuum chamber, 506-upper flange, 506A-vacuum hole, 507-lower flange, 6-cover plate, 7-spiral pipe, 701-spiral tube body, 702-inlet pipe, 703-outlet pipe, 8-temperature control device, 801-heater, 802-thermometer, 803-infusion tube, 804-vacuum tube, 9-lower sealing gasket, 10-upper sealing gasket, 11-vacuum generator, 12-feeding pipe, 13-moisture analyzer. DETAILED DESCRIPTION

[0047] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] See also Figures 1-13 , an embodiment provided by the present invention:

[0049] A particle drainage type temperature controlled spiral pipeline continuous drying system, comprising an airflow generating device 1, a feeder 2, a vacuum drying device 3 and a vacuum generator 11, the vacuum drying device 3 comprising a support assembly 4, a vacuum chamber 5, a cover plate 6 and a spiral pipeline 7, the bottom and top of the vacuum chamber 5 are respectively sealed and fixedly connected to the support assembly 4 and the cover plate 6, the vacuum chamber 5 is provided with an isolated inner cavity 504 and a vacuum cavity 505, the vacuum cavity 505 is connected to a vacuum pump, the inner cavity 504 is filled with a liquid medium, the spiral pipeline 7 is fixed It is fixed in the inner cavity 504 and immersed in the liquid medium. The cover plate 6 is provided with a temperature control device 8 for heating and controlling the temperature of the liquid medium. The upper end of the spiral pipeline 7 extends out of the vacuum chamber 5 and is fixedly connected to one end of the feeder 2. The other end of the feeder 2 is fixedly connected to the airflow generating device 1 by welding or threaded connection. The lower end of the spiral pipeline 7 extends out of the vacuum chamber 5 and is fixedly connected to the vacuum generator 11. A drop pipe 12 is fixedly provided at the bottom of the vacuum generator 11, and a moisture analyzer 13 is fixedly provided on the side wall of the drop pipe 12.

[0050] Among them, the airflow generating device 1 is internally equipped with an induced draft fan, a filtering device, a heating device and a dehumidification device, and is capable of processing the indoor atmosphere in five steps in sequence: primary filtration, induced draft, medium-efficiency filtration, dehumidification, heating and high-efficiency filtration to obtain gas carrying heat energy, kinetic energy, dryness and cleanliness. Since the airflow generating device 1 is heavy, it can be fixed and loaded by using an additional bracket.

[0051] Among them, the feeder 2 includes a discharge barrel 201 and a feed pipe 202. The discharge barrel 201 is vertically fixedly connected to the feed pipe 202, and a feeding device is provided above the discharge barrel 201.

[0052] Among them, the support assembly 4 includes an end cover 401 and several side plates 402. The end cover 401 is provided with a stepped circular inner groove 401A. The radius of the side plate 402 is the same as the radius of the stepped circular inner groove 401A. The side plate 402 is tightly attached to the stepped circular inner groove 401A and the bottom is fixedly connected to the end cover 401. A bottom sealing cover 403 is provided in the center of the end cover 401.

[0053] Among them, the number of side panels 402 is not less than two and not more than four. In this embodiment, the number of side panels is two. The side panels 402 are fan-shaped annular panels, and the fan-shaped expansion angle α is between 30-50°. In this embodiment, α=50°. A group of mounting holes is opened at the bottom of each side panel 402. Each group of mounting holes includes two threaded holes 402A. The angle β between the two threaded holes 402A ranges from 20-40°. In this embodiment, β=40°. The end cover 401 is provided with n groups of stepped holes in the stepped circular inner groove 401A, where n is equal to the number of side panels 402 = 2. Each group of stepped holes includes two stepped holes 401B. The angle between the two stepped holes 401B is equal to β=40°. The adjacent circumferential angles between adjacent groups of stepped holes are 1 / 40. The side plate 402 is fixedly mounted on the end cover 401 by means of countersunk bolts passing through the stepped hole 401B and the threaded hole 402A.

[0054] Among them, the vacuum chamber 5 includes a vacuum tube body 501, an upper flange 506 and a lower flange 507. The vacuum tube body 501 is coaxially provided with an outer tube layer 502 and an inner tube layer 503. The upper and lower ends of the outer tube layer 502 and the inner tube layer 503 are welded to the upper flange 506 and the lower flange 507 respectively. The open area surrounded by the inner tube layer 503 is the inner cavity 504, and the closed area surrounded by the outer tube layer 502, the inner tube layer 503, the upper flange 506 and the lower flange 507 is the vacuum cavity 505. The lower flange 507 is fixedly connected to the end cover 401, and a lower sealing gasket 9 is provided between the lower flange 507 and the end cover 401 to ensure its sealing. The upper flange 506 is fixedly connected to the cover plate 6, and an upper sealing gasket 10 is provided between the upper flange 506 and the cover plate 6 to ensure its sealing. The upper flange 506 is provided with a vacuum hole 506A connected to the vacuum cavity 505, which is used to connect a vacuum pump through a vacuum tube 804. The function of the vacuum chamber 5 is to construct a barrier to shield the liquid medium in the inner cavity 504 from transferring heat outward, so as to improve the heat utilization efficiency of the present invention and reduce the heat transfer consumption to the external atmosphere.

[0055] Among them, the spiral pipeline 7 includes a spiral tube body 701, which is matched and sleeved between the inner layer 503 of the tube body and the side plate 402. The upper and lower ends of the spiral tube body 701 are fixedly connected with an inlet pipe 702 and an outlet pipe 703 respectively. The fixed connection method can be welding or threaded connection. The inlet pipe 702 and the outlet pipe 703 pass through the vacuum tube body 501 and are welded to the vacuum tube body 501 to ensure the sealing of the inlet pipe 702, the outlet pipe 703 and the vacuum chamber 505 to prevent damage to the vacuum environment. The inlet pipe 702 is fixedly connected to the feed pipe 202, and the outlet pipe 703 is fixedly connected to the vacuum generator 11.

[0056] The outer diameter D of the spiral tube 701 is O The inner diameter of the spiral tube body 701 is the same as the inner diameter of the inner layer 503. i The outer diameter of the spiral tube body 701 is the same as that of the side plate 402 , and the helix angle λ of the spiral tube body 701 is between 9° and 12°, so that particles can flow smoothly in the spiral tube body 701 .

[0057] Among them, the temperature control device 8 includes a heater 801, a thermometer 802, an infusion tube 803 and a vacuum tube 804. The heater 801 is fixedly arranged at the center of the cover plate 6 and extends downward into the inner cavity 504 for heating the liquid medium. The thermometer 802 and the infusion tube 803 are fixedly arranged on the cover plate 6 and extend downward into the inner cavity 504 for measuring the temperature of the liquid medium. The vacuum tube 804 is fixedly arranged on the cover plate 6 and extends downward into the vacuum cavity 505 through the vacuum hole 506A. The vacuum tube 804 is connected to the vacuum pump for vacuuming the vacuum cavity 505 to construct a vacuum environment in the vacuum cavity 505.

[0058] The vacuum generator 11 is externally connected to a vacuum pump, which pumps air into the spiral pipe 7. A filter is installed inside the vacuum generator 11 to separate the airflow from the particles during the pumping process. When the vacuum generator 11 is operating, particles flow from the outlet pipe 703 into the vacuum generator 11, where the air is filtered and the particles are separated. When the vacuum generator 11 stops operating momentarily, the particles fall due to their own weight and enter the drop pipe 12. Because the vacuum generator 11 is heavy, an additional bracket can be used to secure the load.

[0059] The above-mentioned particle drainage type temperature-controlled spiral pipeline continuous drying system has the ability to flexibly control wet particles with different initial moisture contents and different water volatilization effects. The ultimate goal of the drying system is to reduce the moisture content of the particles from the initial moisture content ω0 to the target moisture content ω1. To achieve this goal, the drying system of the present invention can realize flexible adjustment based on the following five variables:

[0060] Variable 1: The heating temperature of the airflow generating device 1 can be flexibly adjusted within a certain range (60-80°C) to change the heat transfer effect of the airflow on the particles;

[0061] Variable 2: The operating speed of the induced draft fan in the airflow generating device 1 can be flexibly adjusted within a certain range to control the airflow velocity, thereby changing the initial velocity of the particles and the residence time of the particles in the spiral tube 701, thereby changing the heat transfer effect of the airflow on the particles;

[0062] Variable 3: The temperature of the liquid medium in the inner cavity 504 can be flexibly adjusted within a certain range to change the heat transfer effect of the liquid medium on the spiral tube body 701, and thus change the heat transfer effect of the liquid medium on the particles;

[0063] Variable 4: The absorption pressure of the vacuum generator 11 can be flexibly adjusted within a certain range, thereby changing the outflow rate of the dried particles and the residence time of the particles in the spiral tube 701, thereby changing the heat transfer effect of the airflow on the particles;

[0064] Variable 5: The structural parameters of the spiral tube 701 (nominal diameter d, pitch P, number of turns N) are all adjustable, which can change the length of the path of the particles flowing through the spiral tube 701, thereby changing the residence time of the particles in the spiral tube 701, and thus changing the heat transfer effect of the airflow on the particles.

[0065] By adjusting the above five variables, the best drying effect of the particles can be obtained.

[0066] A particle drainage type temperature-controlled spiral pipeline continuous drying method comprises the following steps:

[0067] S1: Liquid medium is introduced into the inner cavity 504 through the infusion tube 803 until the spiral tube 701 is immersed, and then the infusion is stopped;

[0068] S2: Start the vacuum pump and evacuate the vacuum chamber 505 through the vacuum pipe 804 to maintain a vacuum degree of -5±0.5Pa. The vacuum degree in the vacuum chamber 505 can be monitored by an external pressure gauge.

[0069] S3: Start the heater 801 to heat the liquid medium and the spiral tube body 701 to a temperature of 70±1°C, and use the thermometer 802 to monitor the temperature change of the liquid medium in real time, and form a feedback adjustment with the heating control of the heater 801. With the target temperature of 70°C as the benchmark, the temperature deviation is controlled to ±1°C, thereby creating a hot water medium and a heat preservation environment for the hot water medium;

[0070] S4: Start the airflow generating device 1 and adjust the airflow heating temperature (75°C) and airflow velocity (3.5m / s), start the vacuum generator 11, and form a dry and clean airflow with a certain amount of thermal energy and kinetic energy flowing from the airflow generating device 1 through the feeder 2 and the spiral pipeline 7 to the vacuum generator 11. The airflow generating device 1 is in a blowing action, and the vacuum generator 11 is in a pumping action;

[0071] S5: The feeding device is turned on, and the wet particles (initial room temperature 20-25°C, moisture content ω0 = 29%) enter the feeding pipe 202 through the discharge barrel 201 and flow into the spiral tube body 701 under the action of the airflow formed in step 4. At the same time, heat transfer occurs between the airflow and the spiral tube body 701 to be dehydrated and dried;

[0072] The process by which heat transfer occurs consists of two aspects:

[0073] 1) The temperature of the heated air flow from the air flow generating device 1 is in the range of 60-80°C. The hot air flow propels the particles into the spiral pipe 7, transferring heat to the particles.

[0074] 2) The liquid medium in the inner cavity 504 transfers heat to the spiral tube 701. Under the stable temperature control of the temperature control device 8, the spiral tube 701 basically maintains the same temperature as the liquid medium. As the particles tumble in the spiral tube 701, they also receive heat transferred by the spiral tube 701, thereby volatilizing and dehydrating.

[0075] During the entire particle drainage process, the heat transfer time t depends on the average flow velocity of the particles and the path length of the spiral tube 701. The calculation formula is shown in Formula 1:

[0076] Formula 1:

[0077] Wherein, N is the number of turns of the scanning helical line of the helical tube body 701, d is the nominal diameter of the scanning helical line of the helical tube body 701, P is the pitch of the scanning helical line of the helical tube body 701, and V is the average flow velocity of the particles;

[0078] In this embodiment, N=6.5, d=342mm, P=125mm, V=1m / s, and t=4s after calculation;

[0079] To ensure that the particles have sufficient kinetic energy in the spiral tube 701 and can complete the entire flow in the spiral tube 701, at least the following equilibrium equation (Formula 2) must be satisfied:

[0080] Formula 2:

[0081] Where: -maximum single particle mass, v1-initial velocity of the particle just entering the inlet pipe 702, v2-final velocity of the dried particle entering the outlet pipe 703, when the particle just comes out of the outlet pipe 703, its value is 0, f-friction resistance of a single particle in the spiral tube body 701, H-total height of the spiral tube body 701, N-number of turns of the scanning spiral line of the spiral tube body 701, d-nominal diameter of the scanning spiral line of the spiral tube body 701, P-pitch of the scanning spiral line of the spiral tube body 701.

[0082] In this embodiment, m=0.00015g, H=852.5mm, f=0.000000294N, v2=0, and the initial velocity v1 of the particles just after entering the inlet pipe 702 is calculated to be 3.2m / s. In step S4, the air flow rate can be adjusted with reference to this value so that the initial velocity v1 obtained by the particles is 3.5m / s, meeting the conditions for the particles to flow throughout the spiral tube body 701.

[0083] The flow of particles in the spiral tube 701 also makes full use of the gravitational potential energy at the height H, which saves energy consumption to a certain extent. The energy consumption of drying a single particle is saved by 1.25318×10 -6J, it is estimated that 7 million particles can be transported in one hour, saving 8.7J of energy in one hour.

[0084] After the above treatment, the moisture in the particles is evaporated, and the vacuum generator 11 sucks the particles from the outlet pipe 703 into the drop pipe 12. It is worth noting that when the v2 value is not zero, since the particles have a certain kinetic energy, they can automatically enter the drop pipe 12, and there is no need to turn on the vacuum generator 11 at this time.

[0085] By quantitatively controlling five variables (drainage airflow temperature, drainage airflow velocity, liquid medium temperature, absorption pressure of the vacuum generator 11, and structural parameters of the spiral tube body 701), this drying system ultimately achieved the desired goal of reducing the initial moisture content of the wet particles from ω0 = 29% to within ω1 = 5%.

[0086] S6: The particles dried in step S5 are sucked into the vacuum generator 11 and fall into the drop pipe 12. At the same time, the moisture analyzer 13 detects the absorbance integral area of ​​the near-infrared spectrum in the sensitive band in real time, determines the moisture content through the established detection model, and then compares it with the target moisture content to determine whether the moisture content is qualified, thus completing the particle drying process;

[0087] The moisture analyzer 13 is an indirect near-infrared moisture detection device, and its detection of the moisture content of particles requires the establishment of a detection model.

[0088] The construction of the detection model includes the following steps:

[0089] S1: According to the difference between the air flow heating temperature T1 and the liquid medium heating temperature T2, the following nine combination modes are listed: combination 1: T1 equals 60℃, T2 equals 60℃, combination 2: T1 equals 60℃, T2 equals 70℃, combination 3: T1 equals 60℃, T2 equals 80℃, combination 4: T1 equals 70℃, T2 equals 60℃, combination 5: T1 equals 70℃, T2 equals 70℃, combination 6: T1 equals 70℃, T2 equals 80℃, combination 7: T1 equals 80℃, T2 equals 60℃, combination 8: T1 equals 80℃, T2 equals 70℃, combination 9: T1 equals 80℃, T2 equals 80℃; see Table 1 for details:

[0090]

[0091] Table 1: Modeling combination table

[0092] S2: For the granular material with an initial moisture content of ω0, the absorbance integral area of ​​its near-infrared spectrum in the sensitive band is first detected using the moisture analyzer 13 and recorded as F0. Then, the moisture content value is detected using an externally calibrated KF Karl Fischer moisture meter and recorded as E0.

[0093] S3: The granular material with an initial moisture content of ω0 in step S2 is dried using the nine combinations of step S1 to obtain nine materials in a dry state, which are used as standard materials for modeling. The moisture analyzer 13 is used to detect the absorbance integral area of ​​the nine standard granular materials in the sensitive band, and the absorbance integral areas are recorded as F1, F2, F3, F4, F5, F6, F7, F8, and F9, respectively. The detection spectrum is as follows: Figure 14 As shown, the reflection is at the wavelength of 6150-7350cm -1 The integrated area of ​​the absorbance within the range of the horizontal axis wavelength is then measured using a KF Karl Fischer moisture meter to detect the moisture content of the nine standard granular materials, which are recorded as E1, E2, E3, E4, E5, E6, E7, E8, and E9 respectively. The mapping relationship is shown in Table 2:

[0094]

[0095] Table 2: Modeling calibration table

[0096] S4: As Figure 15 As shown, a functional relationship diagram of absorbance integral area-water content is drawn, that is, a moisture content detection model diagram, and the functional relationship between moisture content and absorbance integral area is obtained as y=0.3235x-244.49, where y is the moisture content and x is the absorbance integral area. Therefore, the absorbance integral area of ​​the particles in the sensitive band can be detected by the moisture analyzer 13 to realize real-time detection of the moisture content of the particles at the drop tube 12. According to the actual stable control of the above five variables at present, during its working process, the real-time curve diagram of the detection results is as follows Figure 16 shown.

[0097] pass Figure 16 It can be concluded that the maximum moisture content of the particles at the drop pipe 12 does not exceed 5%, achieving the expected goal.

[0098] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A particle drainage temperature-controlled spiral pipeline continuous drying system, characterized by: The invention comprises an airflow generating device (1), a feeder (2), a vacuum drying device (3) and a vacuum generator (11), wherein the vacuum drying device (3) comprises a support assembly (4), a vacuum chamber (5), a cover plate (6) and a spiral pipeline (7), wherein the bottom and the top of the vacuum chamber (5) are respectively sealed and fixedly connected to the support assembly (4) and the cover plate (6), the vacuum chamber (5) is provided with an isolated inner cavity (504) and a vacuum cavity (505), the vacuum cavity (505) is connected to a vacuum pump, the inner cavity (504) is filled with a liquid medium, and the spiral pipeline (7) is fixedly provided. The cover plate (6) is placed in the inner cavity (504) and immersed in the liquid medium. The cover plate (6) is provided with a temperature control device (8) for heating and controlling the temperature of the liquid medium. The upper end of the spiral pipe (7) extends out of the vacuum chamber (5) and is fixedly connected to one end of the feeder (2). The other end of the feeder (2) is fixedly connected to the airflow generating device (1). The lower end of the spiral pipe (7) extends out of the vacuum chamber (5) and is fixedly connected to the vacuum generator (11). A drop pipe (12) is fixedly provided at the bottom of the vacuum generator (11), and a moisture analyzer (13) is fixedly provided on the side wall of the drop pipe (12).

2. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 1, characterized in that: The feeder (2) comprises a lower material barrel (201) and a feed pipe (202), wherein the lower material barrel (201) is vertically fixedly connected to the feed pipe (202), and a feeding device is provided above the lower material barrel (201).

3. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 2, characterized in that: The support assembly (4) comprises an end cover (401) and a plurality of side plates (402), wherein the end cover (401) is provided with a stepped circular inner groove (401A), the radius of the side plates (402) is the same as the radius of the stepped circular inner groove (401A), the side plates (402) are closely attached to the stepped circular inner groove (401A) and the bottoms are fixedly connected to the end cover (401), and a bottom sealing cover (403) is provided at the center of the end cover (401).

4. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 3, characterized in that: The number of the side plates (402) is not less than two and not more than four. The side plates (402) are fan-shaped annular plates, and the fan-shaped expansion angle α thereof is between 30-50°. A group of mounting holes is opened at the bottom of each side plate (402), and each group of mounting holes includes two threaded holes (402A). The angle β between the two threaded holes (402A) ranges from 20-40°. The end cover (401) is opened with n groups of stepped holes in the stepped circular inner groove (401A), where n is equal to the number of the side plates (402). Each group of stepped holes includes two stepped holes (401B), and the angle between the two stepped holes (401B) is equal to β. The adjacent circumferential angles between adjacent groups of stepped holes are equal to β. The side plate (402) is fixedly mounted on the end cover (401) by means of countersunk bolts passing through the stepped holes (401B) and the threaded holes (402A).

5. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 3, characterized in that: The vacuum chamber (5) comprises a vacuum tube body (501), an upper flange (506) and a lower flange (507); the vacuum tube body (501) is coaxially provided with an outer tube layer (502) and an inner tube layer (503); the upper and lower ends of the outer tube layer (502) and the inner tube layer (503) are fixedly connected to the upper flange (506) and the lower flange (507) respectively; the open area surrounded by the inner tube layer (503) is an inner cavity (504); the outer tube layer (502), the inner tube layer (503), the upper and lower flanges (506) and the lower flange (507) are fixedly connected to the outer tube layer (502) and the inner tube layer (503) respectively; the open area surrounded by the inner tube layer (503) is an inner cavity (504); The closed area enclosed by the flange (506) and the lower flange (507) is a vacuum chamber (505), the lower flange (507) is fixedly connected to the end cover (401), a lower sealing gasket (9) is provided between the lower flange (507) and the end cover (401), the upper flange (506) is fixedly connected to the cover plate (6), an upper sealing gasket (10) is provided between the upper flange (506) and the cover plate (6), and the upper flange (506) is provided with a vacuum hole (506A) communicating with the vacuum chamber (505).

6. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 5, characterized in that: The spiral pipeline (7) comprises a spiral tube body (701), the spiral tube body (701) being matched and sleeved between the inner layer (503) of the tube body and the side plate (402), the upper and lower ends of the spiral tube body (701) being fixedly connected with an inlet pipe (702) and an outlet pipe (703), respectively, the inlet pipe (702) and the outlet pipe (703) passing through the vacuum tube body (501) and being sealed and fixedly connected to the vacuum tube body (501), the inlet pipe (702) being fixedly connected to the feed pipe (202), and the outlet pipe (703) being fixedly connected to the vacuum generator (11).

7. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 6, characterized in that: The outer diameter D of the spiral tube body (701) O The inner diameter D of the spiral tube body (701) is the same as the inner diameter of the inner layer (503) of the tube body. i The outer diameter of the spiral tube body (701) is the same as that of the side plate (402), and the helix angle λ of the spiral tube body (701) is between 9 and 12 degrees.

8. The particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 6, characterized in that: The temperature control device (8) comprises a heater (801), a thermometer (802), a liquid infusion tube (803) and a vacuum tube (804); the heater (801) is fixedly arranged at the center of the cover plate (6) and extends downward into the inner cavity (504); the thermometer (802) and the liquid infusion tube (803) are fixedly arranged on the cover plate (6) and extend downward into the inner cavity (504); the vacuum tube (804) is fixedly arranged on the cover plate (6) and extends downward into the vacuum cavity (505) through the vacuum hole (506A); and the vacuum tube (804) is connected to a vacuum pump.

9. A drying method for a particle drainage temperature-controlled spiral pipeline continuous drying system according to claim 8, characterized in that: The steps include: S1: injecting liquid medium into the inner cavity (504) through the infusion tube (803) until the spiral tube body (701) is immersed, and then stopping the infusion; S2: Start the vacuum pump and draw vacuum into the vacuum chamber (505) through the vacuum pipe (804), maintaining the vacuum degree at -2 to -10 Pa; S3: Start the heater (801) to heat the liquid medium and the spiral tube (701) to a target temperature within the range of 60 to 80°C, and use the thermometer (802) to monitor the temperature change of the liquid medium in real time, and form a feedback adjustment with the heating control of the heater (801), with the target temperature as the reference, to control the temperature deviation to ±1°C; S4: starting the airflow generating device (1) and adjusting the airflow heating temperature and airflow velocity, starting the vacuum generator (11), and forming a dry clean airflow with a certain amount of thermal energy and kinetic energy that flows from the airflow generating device (1) through the feeder (2), the spiral pipeline (7) to the vacuum generator (11); S5: The feeding device is turned on, and the wet particles enter the feeding pipe (202) through the feeding barrel (201) and flow into the spiral tube body (701) under the action of the airflow formed in step S4, while heat transfer occurs between the airflow and the spiral tube body (701) to perform dehydration and drying; S6: The particles dried in step S5 are sucked into the vacuum generator (11) and fall into the drop pipe (12). At the same time, the moisture analyzer (13) detects the absorbance integral area of ​​its near-infrared spectrum in the sensitive band in real time, and determines its moisture content through the constructed detection model. It is then compared with the target moisture content to determine whether its moisture content is qualified, thereby completing the particle drying process.

10. The drying method according to claim 9, wherein: The construction of the detection model includes the following steps: S1: According to the difference between the air flow heating temperature T1 and the liquid medium heating temperature T2, the following nine combination modes are listed: combination 1: T1 equals 60℃, T2 equals 60℃, combination 2: T1 equals 60℃, T2 equals 70℃, combination 3: T1 equals 60℃, T2 equals 80℃, combination 4: T1 equals 70℃, T2 equals 60℃, combination 5: T1 equals 70℃, T2 equals 70℃, combination 6: T1 equals 70℃, T2 equals 80℃, combination 7: T1 equals 80℃, T2 equals 60℃, combination 8: T1 equals 80℃, T2 equals 70℃, combination 9: T1 equals 80℃, T2 equals 80℃; S2: For the granular material with an initial moisture content of ω0, the absorbance integral area of ​​its near-infrared spectrum in the sensitive band is first detected using a moisture analyzer (13), and recorded as F0. Then, the moisture content value is detected using an externally calibrated KF Karl Fischer moisture meter, and recorded as E0. S3: The granular material with an initial moisture content of ω0 in step S2 is dried using the nine combinations of step S1 to obtain nine materials in a dry state as standard materials for modeling. The moisture analyzer (13) is used to detect the absorbance integral area of ​​the near-infrared spectra of the nine standard granular materials in the sensitive band, and the absorbance integral areas are recorded as F1, F2, F3, F4, F5, F6, F7, F8, and F9, respectively. The moisture content values ​​of the nine standard granular materials are then detected using a KF Karl Fischer moisture analyzer, and the moisture contents are recorded as E1, E2, E3, E4, E5, E6, E7, E8, and E9, respectively. S4: Draw a graph of the absorbance integral area-water content function, i.e., a water content detection model graph.

Images