A natural rubber drying process and device with pretreatment

Abstract

The invention discloses a natural rubber drying process and device with pretreatment, belonging to the technical field of rubber drying. Granulated natural rubber particles are transported to a rubber vehicle by using water containing an anti-adhesive agent. After being loaded into the vehicle, the rubber is preheated and then enters a high-temperature and high-humidity environment of a closed section, and then a water migration inner channel is opened, and then enters a continuous drying section for zoned variable temperature and humidity drying, and finally the vehicle is shipped out after meeting the standards. The device comprises a tunnel-type hot air drying cabinet provided with a plurality of parking spaces for rubber vehicles, the front end parking space of the tunnel is a preheating section, a closed section is arranged thereafter, and all the parking spaces thereafter are continuous drying sections, upper and lower parts of the parking spaces in the tunnel are respectively provided with upper air ducts and lower air ducts, a partition is arranged for each part of the parking spaces on the air duct, and an air inlet and an air outlet are alternately arranged on the air duct between two adjacent partitions. The invention can overcome the adhesion between rubber particles during high-temperature drying, improve the high-temperature tolerance of rubber, increase the drying rate in the deceleration stage, reduce the generation point, and improve the energy utilization rate of the drying system.

Description

Technical Field

[0001] The invention relates to a natural rubber drying process and a device, in particular to a natural rubber drying process and a device with pretreatment, belonging to the technical field of rubber drying. Background Art

[0002] Natural rubber is one of the important materials in modern industry. It is an amorphous polymer with a wide range of application value. It also has some characteristics that cannot be replaced by synthetic rubber. It still has important strategic significance in industrial production. Natural rubber is mainly produced in Southeast Asia and Yunnan, Hainan and other regions in my country. It is not highly concerned, and the primary processing technology and equipment of natural rubber are relatively backward. Natural rubber materials usually go through a series of processes such as crushing, soaking, squeezing, folding, tearing, granulation, drying, weighing, packaging, sampling and grading.

[0003] Drying is a key link in the primary processing of natural rubber, which not only affects the output and energy consumption, but also affects the quality of the product. The current mainstream drying in the industry is tunnel hot air drying. The natural rubber loaded in the trolley passes through the drying cabinet in turn. When the moisture content is lower than 0.8%, it leaves the tunnel and the drying process is completed. The drying process is divided into constant speed drying and deceleration drying. In the latter stage of deceleration drying, the water removal rate is low and the internal moisture migration is very slow, which makes it difficult to increase the overall production capacity. In addition, due to the wide variety of sources of natural rubber, impurities are inevitably mixed into the incoming materials. When some large particles appear during the granulation process, even if the overall moisture content of the rubber reaches below 0.8%, there will still be some unripe white spots distributed inside the rubber. When the amount of white spots is large, it must be returned to the drying tunnel for high-temperature aging, or it can only be crushed again and mixed into new materials to be dried. Practice has found that the main reason for the generation of spots is that the particles are not fine enough during the granulation process of the drying process, or the temperature rises after granulation and they are agglomerated; it is also related to the closure of the internal moisture migration channel.

[0004] In addition, traditional tunnel hot air drying uses higher temperatures to exchange for drying speed. Without affecting the quality of the rubber, the temperature is generally raised to around 125°C, while the speed of the dehumidifying wind is increased to keep the ambient humidity inside the tunnel as low as possible. This seems to make the rubber easier to dry, but in fact it causes a crust to form on the outer surface of the natural rubber, preventing the internal moisture from migrating out, and the moisture content decreases particularly slowly during the deceleration drying stage.

[0005] It can be seen that the traditional drying process of natural rubber faces problems such as long drying time, difficulty in increasing output, high energy consumption, and difficulty in eliminating growth points. Relevant production companies have an urgent need to shorten the drying time of natural rubber, eliminate growth points, and reduce energy consumption. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides a natural rubber drying process and device with pretreatment, which achieves the multiple purposes of increasing the drying rate in the speed reduction drying stage, preventing the heated particles from sticking together after granulation, and reasonably adjusting the temperature and humidity to save energy and reduce consumption.

[0007] The present invention adds two pretreatment processes at the front end of the drying process. One is to add a small amount of anti-sticking additives, i.e., anti-sticking agents, after granulation to keep small gaps between particles and prevent them from sticking. The other is to set a preheating and prewetting section at the front end of the drying process to help open the water transfer channel of natural rubber. In addition, the drying process of the present invention also synchronously adjusts the temperature and humidity of the drying section based on the drying experiment.

[0008] The specific technical solutions disclosed in the present invention are as follows:

[0009] A natural rubber drying process with pretreatment, the process comprising:

[0010] After the initial processing and granulation, the natural rubber particles are hydraulically transported to the rubber truck for loading using water containing anti-sticking agent. After being loaded into the truck, the rubber enters the tunnel-type hot air drying cabinet, where it is first preheated to 50~60℃, and then enters the high temperature and high humidity environment of the closed section to open the water migration channel, and then enters the continuous drying section for drying with zoned variable temperature and humidity parameters until the indicators meet the standards and the vehicle is shipped.

[0011] The anti-sticking agent added to the water for hydraulically conveying natural rubber particles is nano-silicon dioxide, wherein the mass fraction of the anti-sticking agent in the water containing the anti-sticking agent is 1%-3%; the anti-sticking agent nano-silicon dioxide and water act as an isolation agent to prevent the rubber particles from sticking together.

[0012] The stay time of the trolley in each parking space in the tunnel-type hot air drying cabinet is 3 to 6 minutes.

[0013] The specific process of the closed section is: directly spraying high-temperature water vapor; or directly introducing hot water above 90°C from the outside and spraying from the top of the closed section; or spraying with hot water above 90°C for half of the residence time, and then evacuating, the internal high-temperature water flashes instantly, superheated steam appears in the closed space, and the corresponding vacuum degree is maintained. The remaining residence time is switched to the steam surround mode, and the superheated steam is kept surrounding until the trolley moves. Before the trolley moves, the vacuum pump is turned off to restore the internal air pressure.

[0014] The front 2 / 3 parking spaces in the continuous drying section are the front half, and the rear 1 / 3 parking spaces are the rear half. The hot air temperature in the front half is 105-115°C, and the humidity is 10-20%. The hot air temperature in the rear half is 115-125°C, and the humidity is 15-25%. When a drying trolley is in place in the rear half, the dehumidifying wind speed of the entire tunnel is slowed down, the rate of entry of fresh air is reduced, and the relative humidity of this section is maintained in the range of 15-25%. Furthermore, due to the different original moisture contents of the materials to be dried, when the humidity of this section is not enough to reach its humidity range, the time for the trolley to move in and out of the closed section is controlled, so that the closed space door of the closed section is opened and stayed for tens of seconds before moving the trolley, and the door is slowly closed, so that the hot and humid air inside overflows into the continuous drying section, thereby increasing the humidity of this section.

[0015] The present invention also provides the natural rubber drying device with pretreatment, comprising a tunnel-type hot air drying cabinet provided with a plurality of parking spaces for small cars, wherein the interior of the tunnel-type hot air drying cabinet is heated by inputting hot air from various air ports, wherein the parking spaces at the front end of the tunnel, 1 / 7 to 1 / 6, are preheating sections, and thereafter 1 to 2 parking spaces are provided as closed sections, and finally all the parking spaces are continuous drying sections, wherein the upper and lower parts of the parking spaces in the tunnel are provided with upper and lower air ducts respectively, and each of the parking spaces on the upper and lower air ducts is provided with partitions, and the air ducts between two adjacent partitions are provided with air inlets and air outlets alternately;

[0016] A retractable upper trough-shaped door is arranged on the top of the closed section tunnel, and a retractable lower trough-shaped door is symmetrically arranged on the bottom. A closed space is formed when the upper trough-shaped door and the lower trough-shaped door are closed. The middle part of the closed space is a parking space for a dry trolley. A steam pipe is arranged on the top of the closed space, a liquid collecting tank is arranged on the bottom of the closed space, and a water outlet pipe is arranged at the bottom of the liquid collecting tank.

[0017] Spoilers are provided at the top and bottom of the upper air duct and the lower air duct of the preheating section tunnel.

[0018] The upper trough-shaped door and the lower trough-shaped door are of square structure or hemispherical structure, and the enclosed space formed by them is of square or spherical shape. When the upper trough-shaped door and the lower trough-shaped door are of square structure, the upper trough-shaped door constitutes the top surface and half of the left and right side surfaces of the enclosed space, and the lower trough-shaped door constitutes the bottom surface and half of the left and right side surfaces of the enclosed space. When the upper trough-shaped door and the lower trough-shaped door are closed, the left and right side surfaces of the enclosed space are formed, and the side surfaces of the tunnel are fitted therewith to form the front and rear side surfaces of the enclosed space, and finally a square enclosed space is obtained. When the upper trough-shaped door and the lower trough-shaped door are of hemispherical structure, they can form a enclosed space by themselves without having to fit the side surfaces of the tunnel.

[0019] A retractable bracket I is arranged on the top of the closed section tunnel, and the retractable bracket I is connected to the upper groove-shaped door. A retractable bracket II is arranged on the bottom of the closed section tunnel, and the retractable bracket II is connected to the lower groove-shaped door. The retractable bracket I and the retractable bracket II push, pull and retract the upper groove-shaped door and the lower groove-shaped door respectively to realize the opening and closing of the closed space of the closed section; the retractable bracket I and the retractable bracket II are externally connected to motors to control them; sealing strips are arranged on the ends of the upper groove-shaped door and the lower groove-shaped door.

[0020] The steam pipe at the top of the closed space of the closed section is replaced by a hot water pipe, and a number of spray heads are connected below the hot water pipe. An exhaust port is arranged on the side of the closed space, and the exhaust port is connected to a vacuum pump. Sealing components are also arranged at the ends of the upper groove-shaped door and the lower groove-shaped door. The sealing components can be common sealing buckles, or a sinker with internal and external clamping can be arranged at the contact point between the upper groove-shaped door and the lower groove-shaped door, etc., which together with the sealing strip can achieve a better sealing effect.

[0021] A temperature and humidity sensor is also provided in the continuous drying section, and the collected signal is fed back to the controller, and the controller adjusts the wind speed of the air inlet and the air outlet, and then adjusts the temperature and relative humidity in the continuous drying section.

[0022] Compared with traditional tunnel hot air drying, the present invention has the following advantages:

[0023] The drying process of the present invention adopts pretreatment. Before the natural rubber is loaded for drying, a nano-silicon dioxide suspension is mixed into the hydraulically transported fluid, which can not only better isolate the adhesion between particles, but also form polar moisture channels to transport polar substances such as water, while improving the high temperature tolerance of the rubber, making it less likely to adhere even at higher temperatures.

[0024] The drying process and device of the present invention add a preheating section and a closing section before the traditional continuous drying. The closing section realizes the pre-opening of the internal moisture channel in a high temperature and high humidity environment, laying a good foundation for subsequent drying and being conducive to the synchronous migration of internal and external moisture, rather than the crusting that blocks the internal moisture migration channel after surface drying. The drying rate in the deceleration stage can be increased and the generation of hotspots can be inhibited. The preheating section lays the foundation for the overall increase in the temperature of the rubber on the parking space in the closed section, extracts the heat value of the dehumidification wind before it is discarded, makes more effective use of thermal energy, and improves the thermal energy utilization efficiency of the system.

[0025] The drying process and device of the present invention are different from traditional tunnel hot air drying which simply reduces the environmental humidity in the tunnel and increases the drying temperature to increase the output. Instead, it takes into account the coupled effect of temperature and humidity on rubber drying, and finds that increasing the humidity of the drying environment can significantly increase the drying rate in the deceleration stage. During the drying process, keeping the temperature high at first and low at the end, and the humidity high at first and low at the end, or high throughout the process, are all conducive to faster drying. Therefore, the setting of the hot air drying process parameters of the present invention has higher humidity and lower temperature than the traditional drying process, and reduces the frequency of moisture removal wind suction. Its beneficial effects include: reduced fan energy consumption, reduced heat energy supply, shortened drying time, and reduced endogenous points for the same drying time, thereby achieving energy saving, emission reduction, quality improvement and efficiency enhancement in the drying process.

[0026] The present invention can control the temperature and humidity of hot air inlet and outlet in different areas by dividing the drying into sections and the continuous drying sections. The temperature and humidity are detected by sensors, and the air volume and temperature are adjusted by a controller program. This changes the unified and rough production mode in traditional drying tunnels, provides a more refined production method, is more conducive to the intelligent upgrading of production lines, and creates possibilities for further improving product quality and saving energy and reducing consumption.

[0027] The enclosed section added by the present invention only has a closed space with a small number of parking spaces, and the required vacuum degree is not high. It adopts flexible connection, which is easier to implement and can supply the required humidity to the surrounding areas in the tunnel, providing greater possibility for temperature and humidity coupling to optimize the drying process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic flow diagram of the process of the present invention;

[0029] Figure 2 This is a schematic diagram of the structure of the device of Example 3 of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the first two drying parking spaces of the device of Example 4 of the present invention;

[0031] In the figure: 1-parking space; 2-upper air duct; 3-lower air duct; 4-preheating section; 5-enclosed section; 6-continuous drying section; 7-air inlet; 8-air outlet; 9-partition; 10-temperature and humidity sensor; 11-spoiler; 12-upper groove door; 13-steam pipe; 14-hot water pipe; 15-sprinkler head; 16-retractable support frame I; 17-exhaust port; 18-liquid collecting tank; 19-water outlet pipe; 20-lower groove door; 21-retractable support frame II; 22-sealing strip; 23-sealing component. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below through the accompanying drawings and embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0033] The present invention discloses a natural rubber drying process with pretreatment, such as Figure 1 As shown, the process includes: the rubber particles that have been processed by preliminary crushing, soaking, squeezing, washing, flaking, tearing, granulation, and granulation are hydraulically transported to the rubber truck for loading using water added with anti-sticking agent. The loaded rubber enters the tunnel-type hot air drying cabinet for preheating first, then enters the closed high-temperature and high-humidity environment to open the water migration channel, and then enters the continuous drying area for drying with zoned variable temperature and humidity parameters until the indicators meet the standards and the vehicle is shipped.

[0034] Preferably, the stay time of the trolley in each parking space in the tunnel-type hot air drying cabinet is 3 to 6 minutes.

[0035] Preferably, the front 2 / 3 parking spaces in the continuous drying section are the front half, and the rear 1 / 3 parking spaces are the rear half. The hot air temperature in the front half is 105-115°C, and the humidity is 10-20%. The hot air temperature in the rear half is 115-125°C, and the humidity is 15-25%. When a drying trolley is in place in the rear half, the dehumidifying wind speed of the entire tunnel is slowed down, the rate of entry of fresh air is reduced, and the relative humidity of this section is maintained in the range of 15-25%. Due to the different original moisture contents of the materials to be dried, when the humidity of this section is not enough to reach its humidity range, the time for the trolley to move in and out of the closed section is controlled, so that the closed space door of the closed section is opened and stayed for tens of seconds before moving the trolley, and the door is slowly closed, so that the hot and humid air inside overflows into the continuous drying section, thereby increasing the humidity of this section.

[0036] Example 1

[0037] A natural rubber drying device with pretreatment, such as Figure 2 , 3 As shown, a tunnel-type hot air drying cabinet is provided with a plurality of parking spaces for small vehicles. The interior of the tunnel-type hot air drying cabinet is heated by inputting hot air from various air ports. The front 1 / 7 parking spaces of the tunnel are preheating sections 4, followed by 2 parking spaces as closed sections 5, and then all the parking spaces are continuous drying sections 6. The upper and lower parts of the parking spaces in the tunnel are provided with upper air ducts 2 and lower air ducts 3 respectively. Partitions 9 are provided for each portion of parking spaces on the upper air ducts 2 and the lower air ducts 3, and air inlets 7 and air outlets 8 are alternately provided on the air ducts between two adjacent partitions.

[0038] Spoilers 11 are provided at the top and bottom of the upper air duct 2 and the lower air duct 3 of the preheating section 4 tunnel. Specifically, spoilers 11 are provided at the top and bottom of the upper air duct 2 and the lower air duct 3 to increase the resistance and swirl degree of the dehumidifying air inside, so as to more fully exchange heat with the rubber in the drying trolley.

[0039] After the preheating section 4 tunnel is the closed section 5 tunnel;

[0040] A retractable upper trough-shaped door 12 is arranged at the top of the closed section 5 tunnel, and a retractable lower trough-shaped door 20 is symmetrically arranged at the bottom. A retractable bracket Ⅰ16 is arranged at the top of the closed section tunnel, and the retractable bracket Ⅰ16 is connected to the upper trough-shaped door 12. A retractable bracket Ⅱ21 is arranged at the bottom of the closed section tunnel, and the retractable bracket Ⅱ21 is connected to the lower trough-shaped door 20. The retractable bracket Ⅰ16 and the retractable bracket Ⅱ21 are externally connected to a motor, and the motor controls the retractability of the retractable bracket Ⅰ16 and the retractable bracket Ⅱ21. Sealing strips 22 are arranged at the ends of the upper trough-shaped door 12 and the lower trough-shaped door 20. When the upper trough-shaped door 12 and the lower trough-shaped door 20 are closed, a closed space is formed. The middle part of the enclosed space is a dry trolley parking space, a steam pipe 13 is arranged at the top of the enclosed space, a liquid collecting tank 18 is arranged at the bottom of the enclosed space, and a water outlet pipe 19 is arranged at the bottom of the liquid collecting tank 18; the upper trough-shaped door 12 and the lower trough-shaped door 20 of this embodiment are square structures, the upper trough-shaped door 12 constitutes the top surface and half of the left and right sides of the enclosed space, and the lower trough-shaped door 20 constitutes the bottom surface and half of the left and right sides of the enclosed space. When the upper trough-shaped door 12 and the lower trough-shaped door 20 are closed, they form the left and right sides of the enclosed space, and the sides of the tunnel are attached thereto to form the front and rear sides of the enclosed space, and finally a square enclosed space is obtained; the entire tunnel has a total dehumidification port except for the enclosed section 5.

[0041] The device of this embodiment is used to dry natural rubber, and the specific steps are as follows:

[0042] (1) The natural rubber material to be dried is processed by crushing, soaking, squeezing, washing, flaking, tearing and granulating. The granules are loaded into a drying cart by hydraulic conveying. A small amount of anti-sticking agent is added to the conveying water. The anti-sticking agent is nano-silicon dioxide. The mass fraction of the anti-sticking agent in the water containing the anti-sticking agent is 1%. The anti-sticking agent nano-silicon dioxide and water act as a release agent to prevent the rubber particles from sticking together.

[0043] (2) The drying cart has no cover on the top and a support net on the bottom. The loaded rubber enters the tunnel hot air drying cabinet one by one. The first 6 drying carts enter the preheating section 4 of the dehumidification parking space in turn. The cart stays in each parking space for 4 minutes, which allows heat and mass transfer with the still high temperature dehumidification air. The rubber material is preheated. If there is condensed water in the wet air, it is directly discharged from the bottom edge of the tunnel hot air drying cabinet. The dehumidification air preheats the rubber when passing through the material, and the temperature can reach 50~60℃.

[0044] (3) The rubber drying carts exiting the preheating section 4 enter the high-temperature and high-humidity closed section 5 one by one. The closed section 5 is a closed space that accommodates a cart and upper and lower gaps. The upper groove door 12 and the lower groove door 20 are in the initial open state, respectively on the upper and lower sides. After the cart moves into place, the retractable bracket I 16 and the retractable bracket II 21 move to the middle height under the action of the control motor, and the sealing strip 22 contacts and closes, and high-temperature and high-humidity water vapor is introduced from the outside through the steam pipe 13 into the closed space;

[0045] The rubber drying trolley stayed in the enclosed space for a total of 4 minutes before being moved out;

[0046] (4) The car exiting the closed section 5 enters the continuous drying section 6, and moves forward one parking space every 4 minutes. An air inlet 7 is set for every 12 parking spaces in the drying cabinet. The entire tunnel except the closed section 5 has a total dehumidification port. The dehumidification gas flows from back to front. The continuous drying section 6 is divided into two large sections, front and back, each with a number of air inlets 7. The front 2 / 3 of the parking spaces in the continuous drying section 6 are the front half, and the rear 1 / 3 of the parking spaces are the rear half. The temperature and humidity of the front half are set not higher than those of the rear half. In this embodiment, the air inlet temperature of the front half of the continuous drying section 6 is 115°C, and the air inlet temperature of the rear half is 125°C. The humidity of the parking spaces in the front half is kept at 10% and the humidity of the parking spaces in the rear half is kept at 15% by adjusting the dehumidification rate.

[0047] The dehumidifying air of the continuous drying section 6 finally enters the preheating section 4 and is then discharged. The direction and size of the dehumidifying air are controlled by the fan. After the moisture content and degree of maturation of the rubber are tested to be up to standard, the rubber truck is driven out and the drying is completed. After the rubber truck leaves the tunnel, the natural rubber is cooled by fresh air and then enters the next link. The above process is a continuous processing process, and the time the trolley stays in each parking space is the same.

[0048] Example 2

[0049] A natural rubber drying device with pretreatment, wherein the steam pipe 13 at the top of the closed space in Example 1 is replaced by a hot water pipe 14, a plurality of spray heads 15 are connected below the hot water pipe 14, an exhaust port 17 is arranged on the side of the closed space, the exhaust port 17 is connected to a vacuum pump, a sealing member 23 is also arranged at the ends of the upper trough-shaped door 12 and the lower trough-shaped door 20, the sealing member 23 is a sinking platform with internal and external clamping arranged at the contact point between the upper trough-shaped door 12 and the lower trough-shaped door 20, a sealing strip 22 is arranged on the sinking platform, the front end 1 / 6 parking space of the tunnel is the preheating section 4, and the next parking space is the closed section 5, and other components and positional relationships are the same as those in Example 1.

[0050] The device of this embodiment is used to dry natural rubber, and the specific steps are as follows:

[0051] (1) The natural rubber material to be dried is processed by crushing, soaking, squeezing, washing, flaking, tearing and granulating. The granules are loaded into a drying cart by hydraulic conveying. A small amount of anti-sticking agent is added to the conveying water. The anti-sticking agent is nano-silicon dioxide. The mass fraction of the anti-sticking agent in the water containing the anti-sticking agent is 2%. The anti-sticking agent nano-silicon dioxide forms a suspension with water and acts as an isolation agent to prevent the rubber particles from sticking together.

[0052] (2) The drying cart has no cover on the top and a support net on the bottom. The loaded rubber enters the tunnel hot air drying cabinet one by one. The first 7 drying carts first enter the preheating section 4 of the dehumidification parking space. The cart stays in each parking space for 6 minutes, which allows heat and mass transfer with the still high temperature dehumidification air. The rubber material is preheated. If there is condensed water in the wet air, it is directly discharged from the lower edge. The dehumidification air preheats the rubber when passing through the material, and the temperature can reach 50~60℃.

[0053] (3) The rubber drying carts exiting the preheating section 4 enter the high temperature and high humidity closed section 5 one by one. The closed section 5 is a closed space that accommodates one cart and the upper and lower gaps. The upper grooved door 12 and the lower grooved door 20 are in the initial open state, respectively on the upper and lower sides. After the cart moves into place, the retractable bracket I 16 and the retractable bracket II 21 move to the middle height under the action of the control motor, and the sealing strip 22 and the sealing component 23 cooperate to lock the upper grooved door 12 and the lower grooved door 20 to form a completely sealed space. The rubber first receives 90℃ hot water spraying, after more than half of the residence time, the remaining residence time is switched to steam surround mode, specifically, first spray with 90℃ hot water for half of the residence time (3 minutes), then use a high-power vacuum pump to evacuate the space to -50KPa gauge pressure, the boiling point of water is about 82℃, the internal high-temperature water flashes instantly, superheated steam appears in the confined space, maintain the corresponding vacuum degree, and let the superheated steam surround until the trolley moves (3 minutes), and turn off the vacuum pump before the drying trolley moves to restore the internal air pressure;

[0054] The rubber drying trolley stayed in the enclosed space for a total of 6 minutes before being moved out;

[0055] (4) The car exiting the closed section 5 enters the continuous drying section 6, and moves forward one parking space every 6 minutes. An air inlet 7 is set for every 12 parking spaces in the drying cabinet. The entire tunnel except the closed section 5 has a total dehumidification port. The dehumidification gas flows from back to front. The continuous drying section 6 is divided into two large sections, front and back, each with a number of air inlets 7. The front 2 / 3 of the parking spaces in the continuous drying section 6 are the front half, and the rear 1 / 3 of the parking spaces are the rear half. The temperature and humidity of the front half are set not higher than those of the rear half. In this embodiment, the air inlet temperature of the front half of the continuous drying section 6 is 105°C, and the air inlet temperature of the rear half is 105°C. The humidity of the parking spaces in the front half is kept at 18% and the humidity of the parking spaces in the rear half is kept at 20% by adjusting the dehumidification rate.

[0056] The dehumidifying air of the continuous drying section 6 finally enters the preheating section 4 and is then discharged. The direction and size of the dehumidifying air are controlled by the fan. After the moisture content and degree of maturation of the rubber are tested to be up to standard, the rubber truck is driven out and the drying is completed. After the rubber truck leaves the tunnel, the natural rubber is cooled by fresh air and then enters the next link. The above process is a continuous processing process, and the time the trolley stays in each parking space is the same.

[0057] Example 3

[0058] A natural rubber drying device with pretreatment, wherein the steam pipe 13 at the top of the closed space in Example 1 is replaced by a hot water pipe 14, a plurality of spray heads 15 are connected below the hot water pipe 14, an exhaust port 17 is arranged on the side of the closed space, the exhaust port 17 is connected to a vacuum pump, a sealing member 23 is also arranged at the ends of the upper trough-shaped door 12 and the lower trough-shaped door 20, the sealing member 23 is a sinking platform with internal and external clamping arranged at the contact point between the upper trough-shaped door 12 and the lower trough-shaped door 20, a sealing strip 22 is arranged on the sinking platform, the upper trough-shaped door 12 and the lower trough-shaped door 20 are hemispherical structures, the enclosed space formed is spherical, the hemispherical structure itself can form a closed space, and it is not necessary to fit with the side of the tunnel; the front end 1 / 6 parking space of the tunnel is a preheating section 4, and the subsequent parking space is a closed section 5, a temperature and humidity sensor 10 is also arranged in the continuous drying section 6, and the collected signal is fed back to the controller, the controller adjusts the wind speed of the air inlet 7 and the air outlet 8, and then adjusts the temperature and relative humidity in the continuous drying section 6, and other components and position relationships are the same as those in Example 1.

[0059] The device of this embodiment is used to dry natural rubber, and the specific steps are as follows:

[0060] (1) The natural rubber material to be dried is processed by crushing, soaking, squeezing, washing, flaking, tearing and granulating. The granules are loaded into a drying cart by hydraulic conveying. A small amount of anti-sticking agent is added to the conveying water. The anti-sticking agent is nano-silicon dioxide. The mass fraction of the anti-sticking agent in the water containing the anti-sticking agent is 3%. The anti-sticking agent nano-silicon dioxide forms a suspension with water and acts as an isolation agent to prevent the rubber particles from sticking together.

[0061] (2) The drying cart has no cover on the top and a support net on the bottom. The loaded rubber enters the tunnel hot air drying cabinet one by one. The first 7 drying carts first enter the preheating section 4 of the dehumidification parking space. The cart stays in each parking space for 5 minutes, which allows heat and mass transfer with the still high temperature dehumidification air. The rubber material is preheated. If there is condensed water in the wet air, it is directly discharged from the lower edge. The dehumidification air preheats the rubber when passing through the material, and the temperature can reach 50~60℃.

[0062] (3) The rubber drying carts exiting the preheating section 4 enter the high temperature and high humidity closed section 5 one by one. The closed section 5 is a closed space that accommodates a cart and upper and lower gaps. The upper grooved door 12 and the lower grooved door 20 are in the initial open state, respectively on the upper and lower sides. After the cart moves into place, the retractable bracket I 16 and the retractable bracket II 21 move to the middle height under the action of the control motor, and the sealing strip 22 and the sealing component 23 cooperate to lock the upper grooved door 12 and the lower grooved door 20 to form a completely sealed space. The rubber first receives 95 ℃ hot water spraying, after more than half of the residence time, the remaining residence time is switched to steam surround mode, specifically, first spray with 95℃ hot water for half of the residence time (2.5 minutes), then use a high-power vacuum pump to evacuate the space to -50KPa gauge pressure, the boiling point of water is about 82℃, the internal high-temperature water flashes instantly, superheated steam appears in the closed space, maintain the corresponding vacuum degree, and let the superheated steam surround until the trolley moves (2.5 minutes), and turn off the vacuum pump before the drying trolley moves to restore the internal air pressure;

[0063] The rubber drying trolley stays in the enclosed space for a total of 5 minutes before being moved out;

[0064] (4) The car exiting the closed section 5 enters the continuous drying section 6, and moves forward one parking space every 5 minutes. An air inlet 7 is set for every 12 parking spaces in the drying cabinet. The entire tunnel except the closed section 5 has a total dehumidification port. The dehumidification gas flows from back to front. The continuous drying section 6 is divided into two large sections, front and back, each with a number of air inlets 7. The front 2 / 3 of the parking spaces in the continuous drying section 6 are the front half, and the rear 1 / 3 of the parking spaces are the rear half. The temperature and humidity of the front half are set not higher than those of the rear half. In this embodiment, the air inlet temperature of the front half of the continuous drying section 6 is 110°C, and the air inlet temperature of the rear half is 120°C. The humidity of the parking spaces in the front half is kept at 20% and the humidity of the parking spaces in the rear half is kept at 25% by adjusting the dehumidification rate.

[0065] The dehumidifying air of the continuous drying section 6 finally enters the preheating section 4 and is then discharged. The direction and size of the dehumidifying air are controlled by the fan. After the moisture content and degree of maturation of the rubber are tested to be up to standard, the rubber truck is driven out and the drying is completed. After the rubber truck leaves the tunnel, the natural rubber is cooled by fresh air and then enters the next link. The above process is a continuous processing process, and the time the trolley stays in each parking space is the same.

[0066] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A natural rubber drying process with pretreatment, characterized in that the process include: The granulated natural rubber particles are hydraulically transported to the rubber truck for loading using water containing anti-sticking agent. After being loaded into the truck, the rubber enters the tunnel-type hot air drying cabinet, where it is first preheated to 50-60°C, and then enters the high temperature and high humidity environment of the closed section to open the water migration channel, and then enters the continuous drying section for zoned variable temperature and humidity drying until it meets the standards and is shipped out; The anti-sticking agent is nano-silicon dioxide, and the mass fraction of the anti-sticking agent in the water containing the anti-sticking agent is 1% to 3%; The specific process of the closed section is: directly spraying water vapor; or directly spraying with hot water above 90°C; or spraying with hot water above 90°C for half the residence time, and then evacuating, the high-temperature water inside flashes instantly, superheated steam appears in the closed space, and the corresponding vacuum degree is maintained, and the superheated steam is allowed to surround and maintain until the trolley moves. Before the trolley moves, the vacuum pump is turned off to restore the internal air pressure; The front 2 / 3 parking spaces in the continuous drying section are the first half, and the rear 1 / 3 parking spaces are the second half. The hot air temperature in the first half is 105-115°C, and the humidity is 10-20%. The hot air temperature in the second half is 115-125°C, and the humidity is 15-25%.

2. The process for drying natural rubber with pretreatment according to claim 1, characterized in that: The stay time of the trolley in each parking space in the tunnel-type hot air drying cabinet is 3 to 6 minutes.

3. A natural rubber drying device with pretreatment, characterized in that: A method for drying natural rubber with pretreatment as claimed in any one of claims 1 or 2, comprising a tunnel-type hot air drying cabinet provided with a plurality of parking spaces for small vehicles, wherein the parking spaces of the front 1 / 7 to 1 / 6 section of the tunnel are preheating sections (4), followed by 1 to 2 parking spaces as closed sections (5), and finally all parking spaces are continuous drying sections (6), wherein the upper and lower parts of the parking spaces in the tunnel are provided with upper air ducts (2) and lower air ducts (3) respectively, and partitions (9) are provided for each portion of parking spaces on the upper air duct (2) and the lower air duct (3), and air inlets (7) and air outlets (8) are alternately provided on the air ducts between two adjacent partitions; The closed section (5) has a retractable upper trough-shaped door (12) at the top of the tunnel, and a retractable lower trough-shaped door (20) symmetrically arranged at the bottom. When the upper trough-shaped door (12) and the lower trough-shaped door (20) are closed, a closed space is formed. The middle of the closed space is a parking space for a dry trolley. A steam pipe (13) is arranged at the top of the closed space, and a liquid collecting tank (18) is arranged at the bottom of the closed space. A water outlet pipe (19) is arranged at the bottom of the liquid collecting tank (18).

4. The natural rubber drying device with pretreatment according to claim 3, characterized in that: Spoilers (11) are provided at the top and bottom of the upper air duct (2) and the lower air duct (3) of the preheating section (4) tunnel; the upper trough-shaped door (12) and the lower trough-shaped door (20) are of square structure or hemispherical structure, and the enclosed space formed is square or spherical. When the upper trough-shaped door (12) and the lower trough-shaped door (20) are of square structure, the upper trough-shaped door (12) constitutes the top surface and half of the left and right side surfaces of the enclosed space, and the lower trough-shaped door (20) constitutes the bottom surface and half of the left and right side surfaces of the enclosed space. When the upper trough-shaped door (12) and the lower trough-shaped door (20) are closed, they form the left and right side surfaces of the enclosed space, and the side surfaces of the tunnel are attached thereto to form the front and rear side surfaces of the enclosed space, and finally a square enclosed space is obtained; when the upper trough-shaped door (12) and the lower trough-shaped door (20) are of hemispherical structure, they can form the enclosed space by themselves, and do not need to be attached to the side surfaces of the tunnel.

5. The natural rubber drying device with pretreatment according to claim 3, characterized in that: A retractable bracket I (16) is arranged at the top of the closed section (5) tunnel, and the retractable bracket I (16) is connected to the upper groove-shaped door (12). A retractable bracket II (21) is arranged at the bottom of the closed section (5) tunnel, and the retractable bracket II (21) is connected to the lower groove-shaped door (20). The retractable bracket I (16) and the retractable bracket II (21) are externally connected to a motor. The ends of the upper groove-shaped door (12) and the lower groove-shaped door (20) are both provided with sealing strips (22).

6. The natural rubber drying device with pretreatment according to claim 3, characterized in that: The steam pipe (13) at the top of the closed space of the closed section (5) is replaced with a hot water pipe (14), a plurality of spray heads (15) are connected below the hot water pipe (14), an exhaust port (17) is arranged on the side of the closed space, the exhaust port (17) is connected to a vacuum pump, and sealing components (23) are also arranged at the ends of the upper groove-shaped door (12) and the lower groove-shaped door (20).

7. The pre-treated natural rubber drying device according to claim 3, characterized in that: The continuous drying section (6) is also provided with a temperature and humidity sensor, and the collected signals are fed back to the controller.

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