Method and device for continuously drying and screening large-particle triethylene diamine

Abstract

The invention belongs to the technical field of production and preparation of triethylene diamine, and particularly relates to a method and device for continuously drying and screening large-particle triethylene diamine. The invention provides a continuous drying and screening device for large-particle triethylene diamine. The continuous drying and screening device comprises a feeding assembly, a drying assembly, a discharging assembly and the like. The invention further provides a continuous drying and screening method for the large-particle triethylene diamine. The method comprises the steps that the device is utilized, and the vacuum drying cavity is set to be high vacuum of 1-3 kPa (absolute pressure) and low temperature of 25-27 DEG C; carrying out drying treatment on the wet material triethylene diamine, wherein the drying treatment time is 30-45 minutes; and the humidity in the swing screening machine is controlled to be smaller than or equal to 40% RH by introducing nitrogen. By reducing the damage of subsequent drying and screening in production to triethylene diamine particles, effective particle grading is realized, and the continuous production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of production and preparation of triethylenediamine, and in particular relates to a method and a device for continuous drying and screening of large-particle triethylenediamine. Background Art

[0002] Triethylenediamine (also known as 1,4-diazidebicyclo[2.2.2]octane; abbreviated as: TEDA) is an organic synthesis intermediate in the chemical industry, mainly used in various products such as soft and hard polyurethane foams, elastomers, coatings and plastics.

[0003] Triethylenediamine is mainly synthesized by condensation reaction with ethylenediamine, piperazine and its derivatives as raw materials under the action of catalysts, and then obtained through distillation, crystallization, centrifugation, drying and other processes. Based on the fact that data such as particle size and particle size distribution, angle of repose, and moisture absorption rate are important indicators for evaluating particle performance, the inventor analyzed two commercially available triethylenediamine products, and after screening with 18 mesh, 30 mesh, 45 mesh, and 60 mesh sieves and conducting other tests, the particle size ratio, angle of repose, and moisture absorption rate data were measured as shown in Table 1 below:

[0004] Table 1

[0005]

[0006] The above data show that the existing product has a large particle size range, uneven particle size, and a lot of fine powder, and the moisture absorption rate of triethylenediamine is 11.5% (the moisture absorption rate is less than 15% but not less than 2%), which has a certain hygroscopicity. The inventor used a digital push-pull dynamometer to measure the mechanical strength of the particles of the above two commercially available products, which was only 1-2N (the mechanical strength of the commercially available product NaCl is about 5N, and the mechanical strength of anhydrous (NH4)2SO4 is 8-10N). At the same time, it was found through a microscope that there were many small and broken crystals in the finished product. The main reason is that the mechanical strength of triethylenediamine crystals produced by the existing technology is low, and the crystal particles are severely broken due to inappropriate post-processing processes such as centrifugation and drying. Furthermore, the study found that the above commercially available products had serious caking problems after being stored for 3 months.

[0007] Based on the mechanism of agglomeration, it can be known that products with large particles, regular shapes, and uniform shapes have relatively small specific surface areas, relatively large porosity in the product material layer, and good fluidity of the particles, which are not easy to agglomerate. Therefore, the compactness of the agglomerate is related to the particle size of the product particles. The larger the particle size, the less likely it is to agglomerate. The smaller the proportion of triethylenediamine products with small particle size or powder, the less likely it is to agglomerate. At the same time, according to the characteristics of the molecular structure of triethylenediamine, its molecules have two N atoms, which are easy to form hydrogen bonds with water molecules. The hydrogen bonding force is greater than the intermolecular force of triethylenediamine. Triethylenediamine is easy to combine with water molecules and form a stable structure. Therefore, triethylenediamine has a certain hygroscopicity, and triethylenediamine with small particle size or powder has a large hygroscopic surface, which is easy to self-aggregate and cause serious agglomeration, which has a very adverse effect on the quality of the product.

[0008] Based on this, from a mechanism analysis, in order to prevent the agglomeration of triethylenediamine products, it is urgent to solve the problems of particle uniformity, particle size, and anti-hygroscopicity.

[0009] In the prior art (Duan Erhong. Study on the Synthesis and Crystallization Process of 1,4-Diazidobicyclo[2.2.2]octane [D]. Doctoral Dissertation of Tianjin University, 2008.), in order to solve the agglomeration problem, research is often conducted in the crystallization process to improve the uniformity and particle size of triethylenediamine particles, while there are relatively few studies and reports on the effects of the drying and screening post-processing steps of the product on particle breakage, especially no research on the continuous production of triethylenediamine has been reported.

[0010] Patent CN 114394973 A discloses a method for preparing rod-shaped triethylenediamine. First, crude triethylenediamine is added to an ethanol solution and completely dissolved at 55-60°C. Then, white carbon black is added and dispersed evenly. The cooling rate is controlled to be 0.01-0.2°C / min, and the cooling rate is 0.01-0.05°C / min in the cooling range of 45-30°C. The fluid linear velocity is 15-65 cm / s. The temperature is gradually lowered to 15-20°C and maintained for 30-60 minutes. Then, the slurry is separated from the solid and liquid (both embodiments 1 and 2 are filtered by suction). The obtained solid wet material is dried (vacuum dried at 40-45°C and 30-50 kPa (absolute pressure) for 1-6 hours) and sieved to obtain triethylenediamine.

[0011] Patent CN108707155 B discloses triethylenediamine crystals and a preparation method thereof. TEDA crude product is added to a solvent to obtain a TEDA suspension, heated to a dissolution temperature of 60 to 70°C to completely dissolve the solid, then slowly cooled to precipitate crystal seeds, and then the crystals are grown at a constant temperature of 2 to 4°C below the dissolution temperature for 0.5 to 2 hours; after the constant temperature crystal growth is completed, the temperature is further lowered to 20 to 30°C, preferably 23 to 28°C, filtered, and dried (at 45°C, dried at a vacuum degree of 0.08MPa (absolute pressure 21kPa) for 1 to 1.5 hours) to obtain TEDA crystals. More than 85wt% of the TEDA crystals have a particle size of 800 to 1000μm, a purity of 99.3 to 99.8wt%, a water content of less than 2wt%, and a repose angle of 36° to 40°.

[0012] The above patents all have post-drying treatment processes under high temperature (40-45°C) and low vacuum (21kPa, 30-50kPa). Triethylenediamine itself is easy to sublime. When the drying temperature is too high, the crystal form of triethylenediamine will change and the crystals will stick together to form block crystals, which will cause the products to agglomerate during subsequent storage. In addition, the above patents take a long time to dry under high temperature and low vacuum, and the production efficiency is low, which is not conducive to industrial production.

[0013] Patent CN 220507464 U adopts the "vacuum combined with nitrogen purge low temperature drying" process to remove moisture and ethanol from triethylenediamine products, and adds a trace of anti-caking agent during the drying process to delay the agglomeration of triethylenediamine products and improve product quality. However, this method is difficult to mix the trace of anti-caking agent added to the product evenly, which limits the degree of improvement in agglomeration. In addition, the scraper blades and double-screw stirring blades inside the dryer rotate during the drying and stirring process, which will cause serious breakage of triethylenediamine particles and produce a large amount of fine powder. The presence of fine powder will aggravate the agglomeration of particles during subsequent storage, and does not fundamentally solve the agglomeration problem.

[0014] Therefore, in order to achieve continuous production of large-particle triethylenediamine, solve the problem of product storage agglomeration, reduce the crushing of crystal particles by mechanical equipment, solve the problem of crystals sticking together due to high temperature and low vacuum drying, and avoid moisture absorption of finished products during the production process, it is extremely important to develop a new type of continuous drying and screening method and equipment. Summary of the invention

[0015] The technical problem to be solved by the present invention is to provide a method and a device for continuous drying and screening of large-particle triethylenediamine.

[0016] In order to solve the above technical problems, the present invention provides a device for continuous drying and screening of large-particle triethylenediamine, comprising a feeding component, a drying component, and a discharging component;

[0017] The drying assembly comprises a vacuum drying chamber; a crawler driven by a crawler drive motor is arranged in the vacuum drying chamber, and the crawler is directly opposite to the feeding port of the vacuum drying chamber; a vacuum machine and a nitrogen and treatment device are arranged on the vacuum drying chamber;

[0018] The feed assembly comprises a feed tank 1, a feed tank 2 and a distribution tank which are sealed and connected in sequence; the discharge port of the distribution tank is sealed and connected to the feed port of the vacuum drying chamber;

[0019] The discharging assembly comprises a first discharging tank, a second discharging tank and a buffer tank which are sealed and connected in sequence; and a discharging port of the vacuum drying chamber is sealed and connected to a feeding port of the first discharging tank.

[0020] As an improvement of the device for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0021] The discharging assembly also includes a star-shaped rotary valve and a nitrogen positive pressure swing screening machine; the discharging port of the buffer tank is sealed and connected to the nitrogen positive pressure swing screening machine after passing through the star-shaped rotary valve and the material flow pipeline in sequence.

[0022] As a further improvement of the device for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0023] An electric valve 1 is arranged at the feed port of the first feed tank, and an electric valve 2 is arranged between the discharge port of the first feed tank and the feed port of the second feed tank; an electric valve 3 is arranged between the discharge port of the second feed tank and the feed port of the material distribution tank; the electric valve 1, the electric valve 2 and the electric valve 3 constitute an electric feed valve assembly, and the electric feed valve assembly controls the linkage feed;

[0024] A vacuum pump 1 and a nitrogen and treatment device 2 which are connected to the inner cavity of the second feed tank are respectively provided on the top of the second feed tank;

[0025] An electric valve 4 is arranged between the discharge port of the vacuum drying chamber and the feed port of the first feeding tank, and an electric valve 5 is arranged between the discharge port of the first feeding tank and the feed port of the second feeding tank; an electric valve 6 is arranged between the discharge port of the second feeding tank and the feed port of the buffer tank; the electric valve 4, the electric valve 5 and the electric valve 6 constitute an electric discharge valve assembly, and the electric discharge valve assembly controls the linkage discharge;

[0026] A vacuum pump 2 and a nitrogen and treatment device 3 which are connected to the inner cavity of the second feeding tank are respectively provided on the top of the second feeding tank;

[0027] The nitrogen and the treatment device 1 are connected to the buffer tank and the material flow pipeline respectively;

[0028] A temperature and humidity sensor 1 is arranged in the vacuum drying chamber and near its feed port, a temperature and humidity sensor 2 is arranged in the vacuum drying chamber and near its discharge port, a temperature and humidity sensor 3 is arranged on the side wall of the vacuum drying chamber (on the side wall near the middle), and a temperature and humidity detector 4 is arranged at the top entrance of the swing screening machine.

[0029] As a further improvement of the device for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0030] The large-particle triethylenediamine continuous preparation device also has a control center, which is respectively connected to electric valve 1, electric valve 2, electric valve 3, electric valve 4, electric valve 5, electric valve 6, temperature and humidity sensor 1, temperature and humidity sensor 2, temperature and humidity sensor 3, temperature and humidity sensor 4, nitrogen and treatment device 1, nitrogen and treatment device 2, nitrogen and treatment device 3, nitrogen and treatment device 4, vacuum pump 1, vacuum pump 2, star-shaped rotary valve, and swing screen signal.

[0031] As a further improvement of the device for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0032] A material distributing rod assembly which can rotate relative to the material distributing tank is arranged in the inner cavity of the material distributing tank, and the material distributing rod assembly is electrically connected to the material distributing rod motor;

[0033] The distribution rod assembly is composed of a plurality of distribution rods parallel to each other (ie, the distribution rod assembly is a horizontal multi-rod rotating structure), and the distribution rod assembly is perpendicular to the falling trajectory of the material in the distribution tank.

[0034] As a further improvement of the device for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0035] A lower pressing plate is arranged above the crawler in the vacuum drying chamber, and the lower pressing plate is connected to the rotating shaft of the lower pressing plate motor through an L-shaped metal connecting rod; under the action of the lower pressing plate motor driving the metal connecting rod to rotate, the lower pressing plate performs up and down reciprocating motion;

[0036] The thickness of the material can be controlled by adjusting the distance between the lower pressure plate and the track; that is, the distance between the lower pressure plate and the track can be adjusted by adjusting the length of the metal connecting rod connected to the lower pressure plate, thereby controlling the thickness of the material on the track.

[0037] As a further improvement of the device for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0038] A sampling port is provided at the discharge port at the bottom of the buffer tank;

[0039] A cold and hot source heat exchange plate is arranged on the lower surface of the crawler, and the temperature in the vacuum drying chamber is adjusted by utilizing the temperature of water flowing through the cold and hot source heat exchange plate.

[0040] The present invention also provides a method for continuous drying and screening of large-particle triethylenediamine: using the above device, setting the vacuum drying chamber to a high vacuum of 1 to 3 kPa (absolute pressure) and a low temperature of 25 to 27° C.; drying the wet triethylenediamine for 30 to 45 minutes;

[0041] The humidity inside the swing screen was controlled to ≤40% RH by introducing nitrogen.

[0042] As an improvement to the method for continuous drying and screening of large-particle triethylenediamine of the present invention: the screen in the swing screening machine is 45 mesh;

[0043] The bottom plate of the swing screening machine is equipped with a vibrating air hammer to promptly remove smaller particles and fine powder below 45 meshes during the screening process.

[0044] As a further improvement of the method for continuous drying and screening of large-particle triethylenediamine of the present invention, the method comprises the following steps:

[0045] 1) After the main power is turned on, the crawler belt inside the vacuum drying chamber moves at a uniform speed driven by the external crawler belt drive motor and the drive shaft. At the same time, circulating water begins to flow into the external cold and heat source pipeline under the crawler belt to keep the temperature inside the vacuum drying chamber at the set low-temperature drying temperature (25-27°C);

[0046] Nitrogen is introduced into the vacuum drying chamber from the nitrogen and treatment device to replace the air, so that the humidity inside the vacuum drying chamber is maintained within ≤40% RH;

[0047] The temperature and humidity data in the vacuum drying chamber are transmitted to the control center in real time by the temperature and humidity sensor 3. When the internal humidity is detected to be ≤40%RH and the temperature is 25-27℃, the control center starts to command the system to work;

[0048] 2) The system works as follows:

[0049] 2.1) The control center instructs the nitrogen and treatment device 4 to stop working, and at the same time instructs the control electric feed valve assembly to work, so as to carry out linkage feeding, so that the wet material triethylenediamine falls into the distribution tank;

[0050] 2.2) The distribution rod motor drives the distribution rod assembly in the distribution tank to rotate at a constant speed, dispersing the materials falling into the distribution tank; thus, the materials fall evenly onto the crawler in the vacuum drying chamber within a feeding cycle time;

[0051] The motor of the lower pressure plate is in continuous working state, driving the lower pressure plate to level the materials on the track;

[0052] 2.3) The moving crawler drives the material to dry in the vacuum drying chamber for 30 to 45 minutes;

[0053] 2.4) The electric discharging valve components are controlled by the electronic control system to work in linkage:

[0054] Set the time point when the electric discharge valve assembly starts working = the time point when the electric feed valve assembly starts working + the time required for the material to fall into the distribution tank during linkage feeding + the time the material stays in the vacuum drying chamber;

[0055] When the time point when the electric discharging valve assembly starts to work is reached, the control center commands the electric discharging valve assembly to start discharging, so that the dried triethylenediamine falls into the buffer tank;

[0056] 2.5) When the electric discharge valve assembly works in linkage, the control center commands the nitrogen and its processing device to start delivering nitrogen to the buffer tank and the material flow pipeline, thereby removing the air inside. After the air is removed (usually the nitrogen delivery is maintained for 1 to 2 minutes), the nitrogen and its processing device 1 are closed;

[0057] When the electric discharge valve assembly works in linkage, the control center commands the star-shaped rotary valve and the swing screening machine to start working: the dry triethylenediamine in the buffer tank enters the star-shaped rotary valve, and under the action of the star-shaped rotary valve, the material (dried triethylenediamine) is evenly transported to the inside of the swing screening machine; the function of the star-shaped rotary valve is to control the screening feed speed of the swing screening machine to match the screening discharge speed;

[0058] The temperature and humidity detector 4 on the swing screening machine records the temperature and humidity inside the swing screening machine in real time. When the humidity inside the swing screening machine is greater than 40% RH, the control center orders the nitrogen control and its processing device to start working again, and fills nitrogen into the swing screening machine, thereby reducing the humidity inside the swing screening machine to ≤40% RH; when the temperature and humidity detector 4 detects that the humidity inside the swing screening machine is ≤40% RH, the control center orders the nitrogen control and its processing device 1 to stop working.

[0059] As a further improvement of the method for continuous drying and screening of large-particle triethylenediamine of the present invention:

[0060] 1. During linkage feeding (the electric valve 1 is kept normally open during the entire linkage feeding process): the opening degree of the electric valve 1 ensures the feeding speed of the material, and the accumulated amount of the feeding speed within one feeding cycle time matches the amount of material falling after the electric valve 2 is opened;

[0061] The linkage feeding process is:

[0062] Process 1: When the material in the feed tank 1 accumulates a feed cycle time, the electric valve 3 is closed and the electric valve 2 is opened, so that the material in the feed tank 1 (wet triethylenediamine as the starting material) falls into the feed tank 2;

[0063] Process 2: First, under the condition of keeping the electric valve 3 closed, close the electric valve 2 and open the vacuum pump 1 to evacuate the feed tank 2 (so that the negative pressure in the feed tank 2 is the same as the pressure inside the vacuum drying chamber); then open the electric valve 3 to allow the material in the feed tank 2 to fall into the distribution tank;

[0064] Process 3: While keeping the electric valve 2 closed, the electric valve 3 is closed, the nitrogen and treatment device 2 are opened, and nitrogen is introduced into the feed tank 2, thereby breaking the vacuum state in the feed tank 2 (7) (i.e., making the internal pressure of the feed tank 2 and the internal pressure of the feed tank 1 reach equilibrium);

[0065] Then, repeat the above process 1, process 2 and process 3 in a cycle;

[0066] Completing process 1+process 2+process 3 once is defined as completing one cycle, and the time required is defined as one feeding cycle time;

[0067] 2. When discharging materials in linkage:

[0068] First, the time point at which the electric discharge valve assembly starts working is set to be the time point at which the electric feed valve assembly starts working + the time required for the above-mentioned linkage feed process 1 and process 2 + the time the material stays in the vacuum drying chamber;

[0069] When the time point when the electric discharging valve assembly starts working is reached, the control center commands the electric discharging valve assembly to start the linkage discharging work. The linkage discharging process is as follows (the electric valve 4 22 is normally open during the entire linkage discharging process):

[0070] Process 1: Electric valve 5 is closed, electric valve 6 is closed, and when the dried material starts to fall from the conveyor belt to the discharge tank 1, vacuum pump 2 starts to work, making the pressure in the discharge tank 2 the same as that in the discharge tank 1;

[0071] Process 2: While keeping the electric valve 6 closed, the electric valve 5 is opened, so that the material falls from the discharge tank 1 into the discharge tank 2;

[0072] Process 3: Under the condition of keeping the electric valve 6 closed, the electric valve 5 is closed, the nitrogen and treatment device 3 is opened, and nitrogen is introduced into the discharge tank 2, so that the pressure in the discharge tank 2 is close to the pressure inside the buffer tank; then the electric valve 6 is opened, so that the material falls from the material tank 2 into the buffer tank;

[0073] Then, repeat the above process one, process two and process three; repeat the cycle.

[0074] As a further improvement of the method for continuous drying of large-particle triethylenediamine of the present invention:

[0075] When feeding in linkage mode:

[0076] Process 1, duration is 30 seconds;

[0077] Process 2: While keeping the electric valve 3 closed, close the electric valve 2 and open the vacuum pump 1 (41) for 90 seconds; then open the electric valve 3 for 30 seconds;

[0078] Process 3, duration 60 seconds;

[0079] One feeding cycle time is 3 minutes and 30 seconds;

[0080] When discharging in linkage mode:

[0081] Process 1, duration is 90 seconds;

[0082] Process 2, duration is 30 seconds;

[0083] Process 3: The duration of introducing nitrogen into the discharge tank 2 (28) is 1 minute, and then the duration of opening the electric valve 6 (30) is 30 seconds.

[0084] The discharging cycle time is 3 minutes and 30 seconds.

[0085] The invention realizes continuous, low-temperature, high-vacuum and rapid drying of triethylenediamine by adopting belt-type (conveyor belt) drying integrated with swing screening automatic control technology, thereby reducing the drying temperature and crushing rate of the product; and integrates the drying and screening process by automated interlocking technology, thereby realizing continuous drying and screening to obtain a large-particle triethylenediamine product.

[0086] The invention provides a method for continuously producing triethylenediamine large particles, which realizes effective particle classification and improves continuous production efficiency by reducing the damage to triethylenediamine particles caused by subsequent drying and screening.

[0087] The technical points of the present invention are mainly as follows:

[0088] 1. Low-temperature, high-vacuum thin-layer drying technology (25-27°C, absolute pressure 1-3kPa) is adopted to reduce the drying temperature by increasing the vacuum degree to avoid destroying the crystal form and increase the fluidity of the product; at the same time, through the belt static drying method, compared with the existing technology, the present invention can reduce the crushing of particles, and the crushing rate can be reduced by up to 20.2%.

[0089] Note: Static drying means that the sample to be dried is stationary on the conveyor belt (track). Compared with other existing drying technologies, it can reduce the shear force generated by the rotation of mechanical equipment such as stirring and rake teeth, which can cause the breakage of large particle products.

[0090] 2. Use nitrogen micro-positive pressure swing screening technology (swing frequency is 220r / min, ultrasonic frequency is 25Hz) to classify the particles through screening to obtain large-particle triethylenediamine with uniform particle size. Nitrogen is introduced during the screening process to avoid moisture absorption of the product during the production process and enhance the fluidity of the product.

[0091] 3. DCS automatic control technology can be used to integrate drying and screening devices to achieve automatic integrated control and continuous production, with high production efficiency and stable quality.

[0092] 4. Due to the hygroscopic and agglomeration characteristics of triethylenediamine, the linkage addition of nitrogen can intelligently adjust the humidity range inside the screening machine to ≤40% RH, and the introduction of a certain amount of nitrogen from the top can also reduce the floating of fine powder, making the screening process smoother.

[0093] 5. Due to its strong hygroscopicity and poor fluidity, the fine powder of triethylenediamine is easy to adhere to the chassis and the discharge port and cause blockage. The addition of a vibrating air hammer can avoid the accumulation of fine powder on the chassis, avoid clogging the discharge port, and reduce the number of subsequent maintenance and cleaning times.

[0094] The present invention has the following technical effects:

[0095] Through the implementation of the method and device of the present invention, the automation and continuity of the drying and screening process of triethylenediamine can be realized, the labor intensity of workers can be greatly reduced, the level of intelligent processing can be improved, and the production efficiency can be improved.

[0096] Low temperature and high vacuum thin layer continuous belt drying integrated with nitrogen micro-positive pressure swing screening process:

[0097] ① It can reduce the crushing of triethylenediamine particles in the existing drying technology and vibration screening process, and the crushing rate can be reduced by up to 21.5%;

[0098] ② The proportion of particles with a particle size of 45-18 mesh (355-1000μm) can reach 87.09%, and the angle of repose is 28°-32°. There will be no obvious agglomeration phenomenon when stored for more than 6 months, which increases the flowability of the product and solves the storage agglomeration problem.

[0099] Description: The repose angle of the prior art CN108707155 B is 36° to 40°; the repose angle of the prior art CN 114394973 A rod-shaped triethylenediamine is 35° to 40°.

[0100] ③ The moisture content of triethylenediamine finished product is ≤0.03wt%.

[0101] Description: The water content of the triethylenediamine product of the prior art CN 108180700 B is 0.11 wt %. Therefore, the water content technical index of the present invention is reduced by 72.7% compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0103] Figure 1 It is a structural schematic diagram of the present invention;

[0104] Figure 2 for Figure 1 An enlarged schematic diagram of the placing rod assembly 12, etc.;

[0105] Figure 3 for Figure 1 An enlarged schematic diagram of the metal connecting rod 15, the lower pressure plate 16, etc.

[0106] In the figure: stirring motor 1, electric valve 1, feeding tank 1, stirring paddle 1, electric valve 2, stirring motor 2, feeding tank 2, stirring paddle 2, feeding tank 9, electric valve 3, feeding rod motor 11, feeding rod assembly 12, temperature and humidity sensor 1, lower pressure plate motor 14, metal connecting rod 15, lower pressure plate 16, Roots water ring vacuum machine 17, vacuum drying chamber 18, crawler 19, transmission shaft 20, temperature and humidity sensor 2, electric valve 4, stirring motor 3, feeding tank 1, stirring Mixing paddle three 25, electric valve five 26, stirring motor four 27, unloading tank two 28, stirring paddle four 29, electric valve six 30, stirring motor five 31, buffer tank 32, stirring paddle five 33, star-shaped rotary valve 34, nitrogen and treatment device four 35, nitrogen and treatment device one 36, material pipeline 37, temperature and humidity detector four 38, swing screening machine 39, control center 40, vacuum pump one 41, vacuum pump two 42, nitrogen and treatment device two 43, nitrogen and treatment device three 44, sampling port 45, temperature and humidity sensor three 46. DETAILED DESCRIPTION

[0107] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0108] Example 1: A continuous preparation device for large-particle triethylenediamine, such as Figure 1 As shown:

[0109] It includes a feed tank 1 3, a feed tank 2 7, a discharge tank 1 24, and a discharge tank 2 28, and all of the above material storage tanks have visual windows.

[0110] The stirring paddle 1 4 in the feed tank 1 3 is electrically connected to the stirring motor 1 , and the stirring paddle 2 8 in the feed tank 2 7 is electrically connected to the stirring motor 2 6 .

[0111] Feed tank 13, feed tank 27, material distribution tank 9, and vacuum drying chamber 18 are arranged in order from top to bottom; the discharge port of feed tank 3 is sealed and connected to the feed port of feed tank 27, and the discharge port of feed tank 27 is sealed and connected to the feed port of material distribution tank 9; the discharge port of material distribution tank 9 is sealed and connected to the feed port of vacuum drying chamber 18, and a crawler 19 is provided in the vacuum drying chamber 18, and the crawler 19 is directly facing the feed port of vacuum drying chamber 18. The top of feed tank 27 is respectively provided with a vacuum pump 141 and a nitrogen and treatment device 243 connected to the inner cavity of feed tank 27. The function of vacuum pump 141 is to evacuate feed tank 27, and the function of nitrogen and treatment device 243 is to break the vacuum in feed tank 27 to normal pressure.

[0112] An electric valve 12 is provided at the feed port of the feed tank 13, an electric valve 25 is provided between the discharge port of the feed tank 13 and the feed port of the feed tank 27; an electric valve 310 is provided between the discharge port of the feed tank 27 and the feed port of the material distribution tank 9. The electric valve 12, the electric valve 25 and the electric valve 310 constitute an electric feed valve assembly, which controls the linkage feed operation.

[0113] The vacuum drying chamber 18, the unloading tank 1 24, the unloading tank 28, and the buffer tank 32 are arranged in sequence from top to bottom; the vacuum drying chamber 18 is provided with a Roots water ring vacuum machine 17 and a nitrogen and treatment device 4 35, respectively. The Roots water ring vacuum machine 17 is used to evacuate the inner cavity of the vacuum drying chamber 18, and the nitrogen and treatment device 4 35 is responsible for introducing nitrogen into the vacuum drying chamber 18; a temperature and humidity sensor 3 46 is provided on the side wall in the middle of the vacuum drying chamber 18.

[0114] A vacuum pump 242 and a nitrogen and treatment device 344 which are connected to the inner cavity of the unloading tank 28 are respectively provided on the top of the unloading tank 28; the vacuum pump 242 is used to evacuate the inner cavity of the unloading tank 28, and the function of the nitrogen and treatment device 344 is to break the vacuum of the inner cavity of the unloading tank 28 to normal pressure; a sampling port 45 is provided at the discharge port at the bottom of the buffer tank 32.

[0115] The stirring paddle 3 25 in the unloading tank 1 24 is electrically connected to the stirring motor 3 23 , the stirring paddle 4 29 in the unloading tank 28 is electrically connected to the stirring motor 4 27 ; the stirring paddle 5 33 in the buffer tank 32 is electrically connected to the stirring motor 5 31 .

[0116] The discharge port of the vacuum drying chamber 18 is sealedly connected to the feed port of the discharge tank 24, and the discharge port of the discharge tank 24 is sealedly connected to the feed port of the discharge tank 28; the discharge port of the discharge tank 28 is sealedly connected to the feed port of the buffer tank 32; the discharge port of the buffer tank 32 is sealedly connected to the swing screening machine 39 after passing through the star-shaped rotary valve 34 and the material flow pipeline 37 in turn.

[0117] An electric valve four 22 is arranged between the discharge port of the vacuum drying chamber 18 and the feed port of the discharge tank one 24, and an electric valve five 26 is arranged between the discharge port of the discharge tank one 24 and the feed port of the discharge tank two 28; an electric valve six 30 is arranged between the discharge port of the discharge tank two 28 and the feed port of the buffer tank 32; the electric valve four 22, the electric valve five 26, and the electric valve six 30 constitute an electric discharge valve assembly, and the electric discharge valve assembly controls the linkage discharge work.

[0118] A distributing rod motor 11 is arranged on the tank body of the distributing tank 9, and a distributing rod assembly 12 which can rotate relative to the distributing tank 9 is arranged in the inner cavity of the distributing tank 9. Figure 2 As shown, the distributing rod assembly 12 is composed of a plurality of mutually parallel distributing rods, that is, the distributing rod assembly 12 is a horizontal multi-rod rotating structure, and the distributing rod assembly 12 is perpendicular to the falling trajectory of the material in the distributing tank 9; the distributing rod assembly 12 is connected to the distributing rod motor 11, and driven by the distributing rod motor 11, the distributing rod assembly 12 rotates relative to the distributing tank 9, and the material falling from the distributing tank 9 can be evenly dispersed on the crawler 19 after passing through the rotating distributing rod assembly 12.

[0119] The crawler 19 located in the vacuum drying chamber 18 realizes the transportation of materials under the action of the matching crawler drive motor and the drive shaft 20. This is a conventional technology, so it is not elaborated in detail in the present invention. A cold and hot source heat exchange plate is arranged on the lower surface of the crawler 19, and the temperature in the vacuum drying chamber 18 is adjusted by the water temperature flowing through the cold and hot source heat exchange plate.

[0120] A temperature and humidity sensor 13 is arranged in the vacuum drying chamber 18 and near its feed port. The temperature and humidity sensor 13 is used to detect the temperature and humidity of the material before drying. The detected data is transmitted to the control center 40 so that the background can know the temperature and humidity of the material before drying.

[0121] A lower pressing plate 16 is provided in the vacuum drying chamber 18. Figure 3As shown, a lower pressure plate motor 14 is provided on the outer wall of the vacuum drying chamber 18, and the rotating shaft of the lower pressure plate motor 14 is connected to one end of the metal connecting rod 15, and the lower pressure plate 16 is connected to the other end of the metal connecting rod 15. The metal connecting rod 15 is L-shaped. Therefore, under the action of the lower pressure plate motor 14 driving the metal connecting rod 15 to rotate, the lower pressure plate 16 reciprocates up and down, so as to level the material on the crawler 19, thereby reducing the influence of the uneven distribution of the material on the crawler 19 on the drying effect. Furthermore, the thickness of the material can be controlled by adjusting the distance between the lower pressure plate 16 and the crawler 19, and a certain crushing effect is also produced on the material.

[0122] A temperature and humidity sensor 21 is provided in the vacuum drying chamber 18 and near the discharge port of the vacuum drying chamber 18. The temperature and humidity sensor 21 is used to detect the temperature and humidity of the material after drying. The detected data is transmitted to the control center 40 so that the background can know the temperature and humidity of the material after drying.

[0123] The material is dried in the vacuum drying chamber 18 by high vacuum (1-3 kPa, absolute pressure) and low temperature (25-27°C) drying technology. Due to the decrease in the air pressure in the chamber, the boiling points of ethanol, water and organic impurities in triethylenediamine are reduced. By continuously pumping vacuum to maintain a high vacuum, the vaporized water, ethanol and organic impurities can be separated from triethylenediamine.

[0124] The discharge port of the buffer tank 32 is sealedly connected to the swing screening machine 39 after passing through the star-shaped rotary valve 34 and the material flow pipeline 37 in turn, and the nitrogen and treatment device 36 are connected to the buffer tank 32 and the material flow pipeline 37 respectively.

[0125] A temperature and humidity detector 438 is arranged at the top entrance of the swing screening machine 39. The function of the swing screening machine 39 is to classify the triethylenediamine particles and remove the particles with a particle size less than 45 mesh in the product, which is more conducive to subsequent storage.

[0126] The signal transmission relationship in the present invention is as follows:

[0127] The control center 40 is respectively connected with the following components: star-shaped rotary valve 34, swing screening machine 39, vacuum pump 1 41, nitrogen and treatment device 2 43, vacuum pump 2 42, nitrogen and treatment device 3 44, nitrogen and treatment device 1 36; electric valve 1 2, electric valve 2 5, electric valve 3 10, electric valve 4 22, electric valve 5 26, electric valve 6 30; temperature and humidity sensor 1 13, temperature and humidity sensor 2 21, temperature and humidity sensor 3 46, temperature and humidity sensor 4 38, nitrogen and treatment device 4 35. Under the control of the control center 40, the corresponding work is carried out. Finally, the integrated control of drying and screening can be achieved to realize the continuous production of large-particle triethylenediamine.

[0128] For the clarity of the drawing, Figure 1 The dotted lines all represent connections with the control center 40. For the clarity of the drawing, the signal lines of this electric control relationship are omitted in the figure.

[0129] The working process is as follows:

[0130] 1. The main power is started, and the crawler drive motor, transmission shaft 20, stirring motor 1, stirring motor 2 6, cloth rod motor 11, lower pressure plate motor 14, stirring motor 3 23, Roots water ring vacuum machine 17, stirring motor 4 27, stirring motor 5 31, temperature and humidity sensor 1 13, temperature and humidity sensor 2 21, nitrogen and treatment device 4 35, temperature and humidity sensor 4 38, temperature and humidity sensor 3 46 start working and stop working until the main power is turned off.

[0131] The stirring motor 1, stirring motor 2, stirring motor 6, stirring motor 3, stirring motor 23, stirring motor 4, stirring motor 27, and stirring motor 5, 31, respectively drive their respective stirring paddles to start running at 30 r / min.

[0132] The Roots water ring vacuum machine 17 keeps the vacuum pumping operation, and the internal pressure of the vacuum drying chamber 18 is 1-3 kPa (absolute pressure).

[0133] 2. The crawler belt 19 inside the vacuum drying chamber 18 is driven by the external crawler belt drive motor and the drive shaft 20 to achieve uniform motion. At the same time, circulating water begins to flow into the external cold and heat source pipeline under the crawler belt 19 to keep the internal temperature of the vacuum drying chamber 18 at the set low-temperature drying temperature (25-27°C).

[0134] After the main power is started, nitrogen is introduced into the vacuum drying chamber 18 by the nitrogen and treatment device 4 35 for replacement, so that the humidity inside the vacuum drying chamber 18 is maintained within ≤40% RH;

[0135] The temperature and humidity data in the vacuum drying chamber 18 are transmitted to the control center 40 in real time by the temperature and humidity sensor 46. When the internal humidity is detected to be ≤40%RH and the temperature is 25-27°C, the control center 40 starts to command the system to work:

[0136] The details are as follows:

[0137] 2.1) The control center 40 commands the nitrogen and treatment device 24 35 to stop working, and the control center 40 commands the electric feeding valve assembly to work at the same time. The linkage feeding process is as follows (the electric valve 2 remains normally open during the entire linkage feeding process): The opening degree of the electric valve 2 ensures the feeding speed of the material, and the accumulated amount of the feeding speed within 3 minutes and 30 seconds matches the amount of material falling 30 seconds after the electric valve 25 is opened;

[0138] Process 1: When the material in the feed tank 3 accumulates for 3 minutes and 30 seconds, the electric valve 3 10 is closed and the electric valve 2 5 is opened, and the duration is 30 seconds; thereby, the material in the feed tank 3 (wet triethylenediamine as the starting material) falls into the feed tank 2 7.

[0139] Process 2: First, under the condition of keeping the electric valve 3 10 closed, close the electric valve 2 5 and open the vacuum pump 1 41 for 90 seconds (i.e., evacuate the feed tank 2 7 for 90 seconds, so that the negative pressure in the feed tank 2 7 is the same as the internal pressure of the vacuum drying chamber 18); then open the electric valve 3 10 again for 30 seconds, so that the material in the feed tank 2 7 falls into the distribution tank 9;

[0140] Process 3: While keeping the electric valve 25 closed, the electric valve 3 10 is closed, the nitrogen and treatment device 2 43 is opened, and nitrogen is introduced into the feed tank 2 7 for 1 minute; thereby breaking the vacuum state in the feed tank 2 7 (i.e., making the internal pressure of the feed tank 2 7 reach equilibrium with the pressure in the feed tank 1 3).

[0141] Next, repeat the above process 1, process 2 and process 3, and repeat the cycle. Note: Completing process 1+process 2+process 3 once is defined as completing one cycle.

[0142] Therefore, the electric feeding valve assembly works in conjunction with each other and cycles once every 3 minutes and 30 seconds, thereby achieving continuous feeding of triethylenediamine.

[0143] The present invention adopts the above-mentioned feeding tank 1 3, feeding tank 2 7, vacuum pump 1 41 and nitrogen and processing device 2 43 to feed in a linked manner in order to achieve the purpose of maintaining the high vacuum in the vacuum drying chamber 18 at 1 to 3 kPa (absolute pressure).

[0144] 2.2) The distributing rod motor 11 drives the distributing rod assembly 12 in the distributing tank 9 to rotate at a uniform speed, and disperses the materials falling into the distributing tank 9; thereby, the materials in one cycle can further fall evenly onto the crawler 19 in the vacuum drying chamber 18 within 3 minutes and 30 seconds, and ensure that the falling materials are evenly distributed on the crawler 19 with a certain width.

[0145] The lower pressing plate motor 14 is in a continuous working state, driving the lower pressing plate 16 to level the material on the crawler 19. The distance between the lower pressing plate 16 and the crawler 19 can be adjusted by adjusting the length of the metal connecting rod 15 connected to the lower pressing plate, thereby controlling the thickness of the material on the crawler 19.

[0146] 2.3) The temperature and humidity detector 13 continuously records the temperature and humidity of the initial material (wet triethylenediamine material) that enters the vacuum drying chamber 18 and lands on the initial section of the crawler 19;

[0147] The moving crawler 19 drives the material to dry in the vacuum drying chamber 18 for 30 to 45 minutes. When the material is transported to the discharge port of the vacuum drying chamber 18 by the crawler 19, the temperature and humidity detector 21 records the temperature and humidity of the triethylenediamine dry material when it is discharged from the vacuum drying chamber 18.

[0148] 2.4) The electric discharge valve assembly is controlled by the electric control system to work in linkage, as follows:

[0149] First, the time point at which the electric discharge valve assembly starts working is set to be equal to the time point at which the electric feed valve assembly starts working + 2.5 minutes (corresponding to the time required for the above-mentioned linkage feed process 1 and process 2) + the residence time of the material in the vacuum drying chamber 18;

[0150] When the time point when the electric discharging valve assembly starts working is reached, the control center 40 commands the electric discharging valve assembly to start the linkage discharging work. The linkage discharging process is as follows (the electric valve 4 22 is normally open during the entire linkage discharging process):

[0151] Process 1: Electric valve 5 26 is closed, electric valve 6 30 is closed, and when the dried material starts to fall from the conveyor belt 19 to the discharge tank 1 24, vacuum pump 2 42 starts to work for 90 seconds, making the pressure in the discharge tank 28 the same as the pressure in the discharge tank 1 24.

[0152] Process 2: While keeping the electric valve 6 30 closed, the electric valve 5 26 is opened for 30 seconds, so that the material falls from the discharge tank 1 24 into the discharge tank 2 28 .

[0153] Process 3: Under the condition that the electric valve 6 30 is kept closed, the electric valve 5 26 is closed, the nitrogen and treatment device 3 44 are opened, and nitrogen is introduced into the discharge tank 2 28 for 1 minute, so that the pressure in the discharge tank 28 is close to the internal pressure of the buffer tank 33; then the electric valve 6 30 is opened for 30 seconds, so that the material falls from the material tank 28 into the buffer tank 32;

[0154] Then, repeat the above process one, process two and process three; repeat the cycle.

[0155] Therefore, the electric discharging valve assembly works in conjunction with each other and cycles once every 3 minutes and 30 seconds, thereby achieving continuous discharging of triethylenediamine.

[0156] 2.5) When the electric discharge valve assembly works in linkage, the control center 40 commands the nitrogen and its processing device 36 to start delivering nitrogen to the buffer tank 32 and the material flow pipeline 37 (the function of this nitrogen is to remove the air in the buffer tank 32, the material flow pipeline 37 and the inside of the swing screening machine 39), generally maintaining 1 to 2 minutes; then the nitrogen and its processing device 36 are shut down.

[0157] The follow-up is as follows: when the temperature and humidity detector four 38 detects that the humidity inside the swing screening machine 39 is greater than 40% RH, the control center 40 commands the control nitrogen and its processing device one 36 to start working again, and nitrogen is transported to the buffer tank 32 and the material flow pipeline 37, thereby filling the swing screening machine 39 with nitrogen; thereby reducing the humidity inside the swing screening machine 39 to ≤40% RH to prevent the material from clogging the screen; that is, when the temperature and humidity detector four 38 detects that the humidity inside the swing screening machine 39 is ≤40% RH, the control center 40 commands the control nitrogen and its processing device one 36 to stop working.

[0158] When the electric discharge valve assembly works in linkage, the control center 40 commands the star-shaped rotary valve 34 and the swing screen 39 to start working. The dry triethylenediamine in the buffer tank 32 enters the star-shaped rotary valve 34, and under the action of the star-shaped rotary valve 34, the material (dried triethylenediamine) is evenly transported to the inside of the swing screen 39. The function of the star-shaped rotary valve 34 is to control the screening feed speed of the swing screen 39 to match the screening discharge speed, thereby achieving effective screening.

[0159] The temperature and humidity detector 438 on the swing screen 39 records the temperature and humidity inside the swing screen 39 in real time. When the humidity inside the swing screen 39 is greater than 40%RH, the control center 40 commands the nitrogen control and its processing device 136 to start working again, and nitrogen is transported to the buffer tank 32 and the material flow pipeline 37, thereby filling the swing screen 39 with nitrogen, thereby reducing the humidity inside the swing screen 39 to ≤40%RH to prevent the material from clogging the screen. Note: Due to the above-mentioned nitrogen filling process, the pressure in the material flow pipeline 37 can generally be about 0.1~1.0kPa (absolute pressure).

[0160] Description: The present invention adopts nitrogen micro-positive pressure technology to add nitrogen in linkage during the screening process, and intelligently adjusts the humidity range inside the screening machine within ≤40% RH to prevent dry triethylenediamine from absorbing moisture in the air and affecting subsequent storage. After swing screening, the triethylenediamine particles are graded and packaged to finally obtain triethylenediamine large particle finished products.

[0161] The function of the swing screener 39 is to classify the triethylenediamine particles through a 45-mesh screen, remove particles and fine powder with a particle size of less than 45 mesh or smaller in the product, which can greatly reduce the agglomeration of particles and is more conducive to subsequent storage.

[0162] The swing screen 39 is a conventional commercial product. The present invention specifically sets a vibrating air hammer on the bottom plate of the swing screen 39 to timely remove smaller particles and fine powder below 45 meshes during the screening process.

[0163] The invention is that the triethylenediamine wet material after the centrifuge is discharged is transported to the feed tank above the belt vacuum dryer, the switch of the electric valve is controlled by the integrated system, so as to control the transportation of the material in the feed tank, and the high vacuum state inside the vacuum dryer is maintained for continuous drying, the triethylenediamine dry material after complete drying is transported to the discharge tank below, the dried material is continuously transported to the swing screening machine by the star-shaped rotary valve, and the inside of the screening machine is filled with nitrogen under the blowing of nitrogen, and the screening is continuously performed under a slight positive pressure, the large-particle triethylenediamine trapped on the screen is packaged as the finished triethylenediamine, and the fine powder triethylenediamine screened out is moved out of the screening machine under the action of a vibrating air hammer for packaging for the preparation of a liquid triethylenediamine solution, and finally the continuous generation of low-temperature and large-particle triethylenediamine can be realized.

[0164] According to the above process, the following specific experiments are carried out:

[0165] Experiment 1: The component contents and particle distribution of the original triethylenediamine wet material (wet material from the centrifugal section) are shown in Table 2.

[0166] The stirring speeds of the stirring paddle 1-4 in the feed tank 1-3 and the stirring paddle 2-8 in the feed tank 2-7 are both 30 r / min.

[0167] The results detected by the temperature and humidity sensor 13 are that the temperature of the material entering the vacuum drying chamber 18 is 30-35°C and the humidity is 75-80%RH.

[0168] The thickness of the material on the crawler 19 is 2-3 cm. The vacuum degree in the vacuum drying chamber 18 is 1-3 kPa (absolute pressure), and the temperature is controlled at 25-26° C. The material (wet material) is processed in the vacuum drying chamber 18 for 30 minutes. The temperature and humidity detector 21 detects that the material after drying is 25-26° C. and 35-40% RH.

[0169] The triethylenediamine dry material is obtained from the discharge port of the vacuum drying chamber 18, that is, the sample is taken at the sampling port 45. The parameters are shown in Table 2.

[0170] As described above, since nitrogen and its processing device 36 transport nitrogen to ensure that the humidity inside the swing screening machine 39 is controlled to be ≤40% RH, the pressure in the material flow pipeline 37 is a slightly positive pressure, which makes the material flow more smoothly and prevents external air from entering the swing screening machine 39 from the discharge port of the swing screening machine 39.

[0171] The temperature and humidity inside the swing screening machine 39 are controlled to be 25°C and 40%RH respectively; the screen speed is 220r / min (swing frequency is 220r / min, ultrasonic frequency is 25Hz); the mesh number of the screen in the swing screening machine 39 is set to 45 meshes;

[0172] The operation of each component in the whole process is uniformly controlled by the integrated system to achieve continuous processing from triethylenediamine wet material to dry screening.

[0173] The particles sieved on the 45-mesh sieve were selected as the obtained products for packaging. After sieving, the products were sampled for technical index testing, sieving testing and angle of repose measurement. The products were naturally stored in the warehouse for 6 months before the needle penetration measurement was carried out. Detailed analysis data are shown in Table 2.

[0174] Table 2. Analysis data of triethylenediamine at each stage of Experiment 1

[0175]

[0176] The crushing rate of triethylenediamine before and after drying is 1.5%. After being stored for 6 months under normal storage conditions, the penetration test depth reaches 21-25mm (mold depth is 25.5mm), indicating good fluidity, thus proving that it has no agglomeration.

[0177] Note: a. Crushing rate (i.e., the reduction of large particles) = the content of particles with a particle size of ≥30 mesh before drying - the content of particles with a particle size of ≥30 mesh after drying;

[0178] For example, the crushing rate in Experiment 1 is: (13.40%+51.10%)-(10.70%+52.30%)=1.5%.

[0179] b. The penetration, angle of repose and moisture absorption rate of triethylenediamine were tested according to the national standard GB / T 33425-2016 "Evaluation Method for Anti-caking Performance of Anti-caking Agents in Chemical Products". Among them, the penetration was measured using a penetration tester with a mold depth of 25.5 mm. The deeper the needle penetration depth, the lower the compactness of the product agglomeration, that is, the looser the product and the better the fluidity.

[0180] Comparative Example 1: Change the "high vacuum and low temperature thin layer drying" in Experiment 1 to the conventional "vacuum spiral ribbon drying technology":

[0181] The details are as follows:

[0182] The “vacuum drying chamber 18” in Experiment 1 was changed to “vacuum screw belt dryer, stirring speed is 30 rpm / min”, and the rest was the same as Experiment 1.

[0183] The analysis data of the obtained products are compared in Table 3:

[0184] Table 3

[0185]

[0186] Note: The wet ingredients are the same as Table 2.

[0187] The vacuum spiral belt drying was adopted, and the crushing rate of triethylenediamine before and after drying was (13.40%+51.10%)-(6.60%+36.20%)=21.7%.

[0188] The crushing rate of comparative example 1 increased by: 21.7% - 1.5% = 20.2%; the increase in fine powder = the difference in the proportion of particles with a particle size of <45 mesh before and after screening, that is, 25.70% - 12.50% = 13.20%.

[0189] The dry material dried by vacuum spiral belt drying technology was screened under the same conditions. The increase in the amount of fine powder led to a decrease in screening efficiency. The increase in the fine powder content in the product caused the compactness of the product agglomerates to be 2.9 times that of Experiment 1 (25.2÷8.6=2.9) during the subsequent storage process.

[0190] Note: The compactness multiple of agglomeration = the needle penetration value of the sieved product of Experiment 1 of the present invention ÷ the needle penetration value of the sieved product of the comparative example.

[0191] Comparative Example 2: Change the "high vacuum and low temperature thin layer drying" in Experiment 1 to the conventional "low vacuum and high temperature thin layer drying":

[0192] The details are as follows:

[0193] The parameters of the "vacuum drying chamber 18" in Experiment 1, "vacuum degree 1~3kPa (absolute pressure), temperature 25~26°C)" are changed to "high temperature (40~45°C), low vacuum (10~25kPa (absolute pressure)", and the rest are the same as Experiment 1.

[0194] The analysis data of the obtained products are compared in Table 4:

[0195] Table 4

[0196]

[0197] During the low vacuum and high temperature thin layer drying process, the particles were bonded, and the breakage rate before and after the drying process change = the content of particles with a particle size of ≥30 mesh after drying in Experiment 1 of the present invention - the content of particles with a particle size of ≥30 mesh after drying in Comparative Example 2, specifically (41.10% + 40.60%) - (10.70% + 52.30%) = -18.7%. After 6 months of storage, the compactness of the product agglomeration was 16.8 times that of Experiment 1 (25.2÷1.5=16.8).

[0198] Comparative Example 3: The "nitrogen micro-positive pressure swing screening" in Experiment 1 was changed to the conventional "nitrogen micro-positive pressure vibration screening", and the rest was the same as Experiment 1.

[0199] At the same production capacity, the obtained product analysis data is compared in Table 5:

[0200] Table 5

[0201]

[0202]

[0203] In contrast, the vibration screening crushing rate was (12.29% + 60.09%) - (10.76% + 52.63%) = 9.0%, and the increase in fine powder was 4.40% - 0.61% = 3.8%. After 6 months of storage, the compactness of the product agglomerate was 1.6 times that of Experiment 1 (25.2 ÷ 15.4 = 1.6).

[0204] Comparative Example 4-1: The "temperature and humidity inside the swing screening machine 39 is 25°C, 40%RH" in Experiment 1 is changed to "35°C, 40%RH", and the rest is the same as Experiment 1.

[0205] The analysis data of the obtained products are compared in Table 6:

[0206] Table 6

[0207]

[0208] The crushing rate is (12.29%+60.09%)-(11.71%+59.57%)=1.1%, and the increase in fine powder is 1.07%-0.61%=0.5%. The product has good fluidity and no obvious agglomeration.

[0209] Comparative Example 4-2: Change the "temperature and humidity inside the swing screening machine 39 to 25°C, 40%RH" in Experiment 1 to "25°C, 75%RH", and the rest is the same as Experiment 1.

[0210] The analysis data of the obtained products are compared in Table 7:

[0211] Table 7

[0212]

[0213] The crushing rate was (12.29% + 60.09%) - (11.75% + 57.42%) = 3.2%, and the increase in fine powder was 5.03% - 0.61% = 4.4%. After 6 months of storage, the compactness of the product agglomerates was 2.0 times that of Experiment 1 (25.2 ÷ 12.3 = 2.0).

[0214] Comparative Example 5, removing the "star-shaped rotary valve 34" in Example 1; the resulting situation is changed as follows: the buffer tank 32 is connected to the swing screening machine 39, the screening feed speed and the screening discharge speed cannot match, and the fine powder is directly removed from the finished product discharge port without being screened; the rest is equivalent to Experiment 1.

[0215] The obtained product analysis data are compared in Table 8:

[0216] Table 8

[0217]

[0218] The crushing rate is (12.29% + 60.09%) - (10.81% + 53.92%) = 7.7%, and the increase in fine powder is 10.90% - 0.61% = 10.3%. After 6 months of storage, the compactness of the product agglomerates is 2.6 times that of Experiment 1 (25.2 ÷ 9.8 = 2.6).

[0219] Comparative Example 6: The "star-shaped rotary valve 34" in Example 1 was replaced with a "screw conveying valve"; the screw conveying extrusion caused the crushing of the finished particles to increase during the conveying process, and the rest was the same as Experiment 1.

[0220] The obtained product analysis data are compared in Table 9:

[0221] Table 9

[0222]

[0223] The crushing rate is (12.29% + 60.09%) - (11.61% + 56.77%) = 4.0%, and the increase in fine powder is 2.12% - 0.61% = 1.5%. After 6 months of storage, the compactness of the product agglomeration is 1.4 times that of Experiment 1 (25.2 ÷ 18.1 = 1.4), and there is a certain amount of agglomeration.

[0224] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A device for continuous drying and screening of large-particle triethylenediamine, characterized in that: It includes a feeding component, a drying component and a discharging component; The drying assembly comprises a vacuum drying chamber (18); a crawler (19) driven by a crawler transmission motor is arranged in the vacuum drying chamber (18), and the crawler (19) faces the feed port of the vacuum drying chamber (18); a vacuum machine (17) and a nitrogen and treatment device four (35) are arranged on the vacuum drying chamber (18); The feed assembly comprises a feed tank 1 (3), a feed tank 2 (7) and a distribution tank (9) which are sealed and connected in sequence; the discharge port of the distribution tank (9) is sealed and connected to the feed port of the vacuum drying chamber (18); The discharge assembly comprises a discharge tank 1 (24), a discharge tank 2 (28), and a buffer tank (32) which are sealed and connected in sequence; the discharge port of the vacuum drying chamber (18) is sealed and connected to the feed port of the discharge tank 1 (24); The discharge assembly further comprises a star-shaped rotary valve (34) and a swing screening machine (39); the discharge port of the buffer tank (32) is sealedly connected to the swing screening machine (39) after passing through the star-shaped rotary valve (34) and the material flow pipeline (37) in sequence.

2. The device for continuous drying and screening of large-particle triethylenediamine according to claim 1, characterized in that: An electric valve one (2) is arranged at the feed port of the first feed tank (3), and an electric valve two (5) is arranged between the discharge port of the first feed tank (3) and the feed port of the second feed tank (7); an electric valve three (10) is arranged between the discharge port of the second feed tank (7) and the feed port of the material distribution tank (9); the electric valve one (2), the electric valve two (5) and the electric valve three (10) constitute an electric feed valve assembly, and the electric feed valve assembly controls the linkage feed; A vacuum pump (41) and a nitrogen and treatment device (43) are provided on the top of the second feed tank (7) respectively, which are connected to the inner cavity of the second feed tank (7); An electric valve four (22) is arranged between the discharge port of the vacuum drying chamber (18) and the feed port of the first discharge tank (24), and an electric valve five (26) is arranged between the discharge port of the first discharge tank (24) and the feed port of the second discharge tank (28); an electric valve six (30) is arranged between the discharge port of the second discharge tank (28) and the feed port of the buffer tank (32); the electric valve four (22), the electric valve five (26), and the electric valve six (30) constitute an electric discharge valve assembly, and the electric discharge valve assembly controls the linkage discharge; A second vacuum pump (42) and a third nitrogen and treatment device (44) which are connected to the inner cavity of the second unloading tank (28) are respectively provided on the top of the second unloading tank (28); The nitrogen and treatment device 1 (36) are respectively connected to the buffer tank (32) and the material flow pipeline (37); A temperature and humidity sensor 3 (46) is provided on the side wall of the vacuum drying chamber (18), and a temperature and humidity detector 4 (38) is provided at the top entrance of the swing screening machine (39).

3. The device for continuous drying and screening of large-particle triethylenediamine according to claim 2, characterized in that: The large particle triethylenediamine continuous preparation device also has a control center (40), and the control center (40) is respectively connected to the electric valve 1 (2), the electric valve 2 (5), the electric valve 3 (10), the electric valve 4 (22), the electric valve 5 (26), the electric valve 6 (30), the temperature and humidity sensor 1 (13), the temperature and humidity sensor 2 (21), the temperature and humidity sensor 3 (46), the temperature and humidity sensor 4 (38), the nitrogen and treatment device 1 (36), the nitrogen and treatment device 2 (43), the nitrogen and treatment device 3 (44), the nitrogen and treatment device 4 (35), the vacuum pump 1 (41), the vacuum pump 2 (42), the star-shaped rotary valve (34), and the swing screening machine (39) by signal.

4. The device for continuous drying and screening of large-particle triethylenediamine according to claim 3, characterized in that: A distributing rod assembly (12) which can rotate relative to the distributing tank (9) is arranged in the inner cavity of the distributing tank (9), and the distributing rod assembly (12) is electrically connected to the distributing rod motor (11); The distribution rod assembly (12) is composed of a plurality of distribution rods parallel to each other, and the distribution rod assembly (12) is perpendicular to the falling trajectory of the material in the distribution tank (9).

5. The device for continuous drying and screening of large-particle triethylenediamine according to claim 4, characterized in that: A lower pressing plate (16) is provided above the crawler belt (19) in the vacuum drying chamber (18), and the lower pressing plate (16) is connected to the rotating shaft of the lower pressing plate motor (14) through an L-shaped metal connecting rod (15); when the lower pressing plate motor (14) drives the metal connecting rod (15) to rotate, the lower pressing plate (16) performs up and down reciprocating motion; The thickness of the material can be controlled by adjusting the distance between the lower pressing plate (16) and the crawler belt (19).

6. A method for continuous drying and screening of large-particle triethylenediamine, characterized in that: Using the device as claimed in any one of claims 1 to 5, the vacuum drying chamber (18) is set to a high vacuum of 1 to 3 kPa and a low temperature of 25 to 27° C.; the wet triethylenediamine is dried for 30 to 45 minutes; The humidity inside the swing screening machine (39) is controlled to be ≤40%RH by introducing nitrogen.

7. The method for continuous drying and screening of large-particle triethylenediamine according to claim 6, characterized in that: The screen in the swing screening machine (39) is 45 mesh; The bottom plate of the swing screening machine (39) is provided with a vibrating air hammer, which is used to timely remove smaller particles and fine powders below 45 meshes during the screening process.

8. The method for continuous drying and screening of large-particle triethylenediamine according to claim 7, characterized in that The following steps are involved: 1) After the main power supply is started, the crawler belt (19) inside the vacuum drying chamber (18) is driven by the external crawler belt drive motor and the drive shaft (20) to achieve uniform motion, and at the same time, circulating water begins to flow into the external cold and hot source pipeline below the crawler belt (19), so that the internal temperature of the vacuum drying chamber (18) is maintained at the set low-temperature drying temperature; Nitrogen is introduced into the vacuum drying chamber (18) from the nitrogen treatment device (35) for replacement, so that the humidity inside the vacuum drying chamber (18) is maintained within 40% RH; The temperature and humidity data in the vacuum drying chamber (18) are transmitted to the control center (40) in real time by the temperature and humidity sensor 3 (46). When the internal humidity is detected to be ≤40%RH and the temperature is 25-27°C, the control center (40) starts to command the system to work; 2) The system works as follows: 2.1) The control center (40) instructs the nitrogen and treatment device 4 (35) to stop working, and the control center (40) instructs the electric feed valve assembly to work at the same time, so as to carry out linked feeding, so that the wet material triethylenediamine falls into the distribution tank (9); 2.2) The distribution rod motor (11) drives the distribution rod assembly (12) in the distribution tank (9) to rotate at a uniform speed, so as to disperse the materials falling into the distribution tank (9); thereby, the materials evenly fall onto the crawler belt (19) in the vacuum drying chamber (18) within a feeding cycle time; The lower pressing plate motor (14) is in a continuous working state, driving the lower pressing plate (16) to level the materials on the crawler belt (19); 2.3) The moving crawler (19) drives the material to dry in the vacuum drying chamber (18) for 30 to 45 minutes; 2.4) The electric discharging valve components are controlled by the electronic control system to work in linkage: The time point at which the electric discharge valve assembly starts to work is set to be equal to the time point at which the electric feed valve assembly starts to work + the time required for the material to fall into the material distribution tank (9) during the linkage feed + the time the material stays in the vacuum drying chamber (18); When the time point at which the electric discharging valve assembly starts to work is reached, the control center (40) commands the electric discharging valve assembly to start discharging work, thereby allowing the dried triethylenediamine to fall into the buffer tank (32); 2.5) When the electric discharge valve assembly works in conjunction, the control center (40) commands the nitrogen and its processing device (36) to start delivering nitrogen to the buffer tank (32) and the material flow pipeline (37), thereby removing the air inside. After the air is removed, the nitrogen and its processing device (36) are closed; When the electric discharge valve assembly works in linkage, the control center (40) commands the star-shaped rotary valve (34) and the swing screening machine (39) to start working: the dry triethylenediamine in the buffer tank (32) enters the star-shaped rotary valve (34), and under the action of the star-shaped rotary valve (34), the material is evenly transported to the inside of the swing screening machine (39); the function of the star-shaped rotary valve (34) is to control the screening feed speed of the swing screening machine (39) to match the screening discharge speed; The temperature and humidity detector four (38) on the swing screening machine (39) records the temperature and humidity inside the swing screening machine (39) in real time. When the humidity inside the swing screening machine (39) is greater than 40% RH, the control center (40) commands the nitrogen control and its processing device (36) to start working again, and fills nitrogen into the swing screening machine (39), thereby reducing the humidity inside the swing screening machine (39) to ≤40% RH; when the temperature and humidity detector four (38) detects that the humidity inside the swing screening machine (39) is ≤40% RH, the control center (40) commands the nitrogen control and its processing device one (36) to stop working.

9. The method for continuous drying and screening of large-particle triethylenediamine according to claim 8, characterized in that:

1. When feeding in linkage mode: the opening degree of the electric valve 1 (2) ensures the feeding speed of the material, and the accumulated amount of the feeding speed in one feeding cycle time matches the amount of material falling after the electric valve 2 (5) is opened; The linkage feeding process is: Process 1: When the material in the feed tank 1 (3) accumulates a feed cycle time, the electric valve 3 (10) is closed and the electric valve 2 (5) is opened; thereby, the material in the feed tank 1 (3) falls into the feed tank 2 (7); Process 2: First, while keeping the electric valve 3 (10) closed, close the electric valve 2 (5) and open the vacuum pump 1 (41) to evacuate the feed tank 2 (7); then open the electric valve 3 (10) again, so that the material in the feed tank 2 (7) falls into the distribution tank (9); Process 3: While keeping the electric valve 2 (5) closed, the electric valve 3 (10) is closed, the nitrogen and treatment device 2 (43) is opened, and nitrogen is introduced into the feed tank 2 (7), thereby breaking the vacuum state in the feed tank 2 (7); Then, repeat the above process 1, process 2 and process 3 in a cycle; Completing process 1+process 2+process 3 once is defined as completing one cycle, and the time required is defined as one feeding cycle time; 2. When discharging materials in linkage: First, the time point at which the electric discharge valve assembly starts to work is set to be equal to the time point at which the electric feed valve assembly starts to work + the time required for the above-mentioned linked feed process 1 and process 2 + the time the material stays in the vacuum drying chamber (18); When the time point when the electric discharging valve assembly starts to work is reached, the control center (40) commands the electric discharging valve assembly to start the linkage discharging work. The linkage discharging process is as follows: Process 1: The electric valve 5 (26) is closed, the electric valve 6 (30) is closed, and when the dried material starts to fall from the conveyor belt (19) to the discharge tank 1 (24), the vacuum pump 2 (42) starts to work, so that the pressure in the discharge tank 2 (28) is the same as the pressure in the discharge tank 1 (24); Process 2: While keeping the electric valve 6 (30) closed, the electric valve 5 (26) is opened, so that the material falls from the discharge tank 1 (24) into the discharge tank 2 (28); Process 3: Under the condition that the electric valve 6 (30) is kept closed, the electric valve 5 (26) is closed, the nitrogen and treatment device 3 (44) is opened, and nitrogen is introduced into the discharge tank 2 (28), so that the pressure in the discharge tank 2 (28) is close to the pressure inside the buffer tank (33); then the electric valve 6 (30) is opened, so that the material falls from the material tank 2 (28) into the buffer tank (32); Then, repeat the above process one, process two and process three; repeat the cycle.

10. The method for continuous drying and screening of large-particle triethylenediamine according to claim 9, characterized in that: When feeding in linkage mode: Process 1, duration is 30 seconds; Process 2: While keeping the electric valve 3 (10) closed, close the electric valve 2 (5) and open the vacuum pump 1 (41) for 90 seconds; then open the electric valve 3 (10) again for 30 seconds; Process 3, duration 60 seconds; When discharging in linkage mode: Process 1, duration is 90 seconds; Process 2, duration is 30 seconds; Process 3: The duration of introducing nitrogen into the discharge tank 2 (28) is 1 minute, and then the duration of opening the electric valve 6 (30) is 30 seconds.

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