Bisphenol A rotary granulation system and method

Abstract

The invention discloses a bisphenol A rotary granulation system and method, and relates to the technical field of bisphenol A. The bisphenol A rotary granulation system comprises a granulation tower and a nitrogen cooling system used for cooling bisphenol A liquid drops, the nitrogen cooling system comprises a nitrogen inlet formed in the bottom of the granulation tower and a nitrogen outlet formed in the top of the granulation tower, and in the nitrogen cooling system, a nitrogen inlet is formed in the bottom of the granulation tower and a nitrogen outlet is formed in the top of the granulation tower; the temperature of a nitrogen inlet is 40-45 DEG C, and the temperature of a nitrogen outlet is 80-90 DEG C. According to the bisphenol A rotary granulation system and method provided by the invention, when the temperature of a nitrogen inlet is controlled between 40 DEG C and 45 DEG C in a granulation tower, nitrogen exchanges heat with bisphenol A so as to enable the temperature of a nitrogen outlet to be between 80 DEG C and 90 DEG C, so that the temperature when bisphenol A is discharged is controlled between 60 DEG C and 70 DEG C, and bisphenol A particles are prevented from adhering and blocking equipment and pipelines as much as possible; meanwhile, the situation that bisphenol A particles are broken is reduced, generation of fine powder is reduced, and the proportion of the fine powder is controlled to be about 0.55%.

Description

Technical Field

[0001] The present invention relates to the technical field of bisphenol A granulation, and particularly relates to a bisphenol A rotary granulation system and method. Background Art

[0002] Bisphenol A is an important chemical raw material, which is widely used in the production of materials such as polycarbonate and epoxy resin. Its granulation process is to convert molten bisphenol A into solid particles for easy storage and sales.

[0003] The nitrogen cooling granulation of bisphenol A is a process in which the heated and molten bisphenol A melt is sprayed in a granulation tower, and the bisphenol A droplets are condensed and solidified after contacting with low-temperature nitrogen, thereby obtaining granular bisphenol A products.

[0004] For example, in the patent document with the application publication number CN117443279A, the application publication date of January 26, 2024, and the name of "A Spraying Disk Structure for Nitrogen Cooling Granulation of Bisphenol A", it includes a spraying disk body, and a number of spray holes are provided on the spraying disk body. By opening a steam channel on the spraying disk, the temperature of the spraying disk is always higher than the melting point temperature of bisphenol A, preventing bisphenol A from condensing and blocking.

[0005] During the granulation process of bisphenol A, the temperature of nitrogen directly affects the temperature of bisphenol A particles. The higher the nitrogen temperature in the tower, the higher the outlet temperature of bisphenol A particles, and the easier the bisphenol A particles are to adhere and block the equipment and pipelines. On the contrary, the lower the nitrogen temperature in the tower, the lower the outlet temperature of bisphenol A particles, and the easier the bisphenol A particles are to break, and the larger the amount of dust.

[0006] In the prior art, the average particle size of the material is often controlled by adjusting parameters, and the proportion of fine powder is often ignored. Fine powder generally refers to bisphenol A particles with a particle size ≤ 0.5 mm. Bisphenol A particles of this size will be suspended in the granulation tower with the flow of the gas in the granulation tower, resulting in dust pollution. That is, bisphenol A particles with a size ≤ 0.5 mm are the core components of dust pollution.

[0007] During the cooling granulation process, too much fine powder will not only cause pollution but also increase the danger index of the operation. For example, in the above-mentioned patent document with the name of "A Spraying Disk Structure for Nitrogen Cooling Granulation of Bisphenol A", it can control the average particle size of the material at 1.1 mm, but the proportion of fine powder below 0.5 mm still accounts for 1%. Obviously, the proportion of fine powder in the overall output of bisphenol A is too small and difficult to control individually, and too much fine powder suspended in the granulation tower will cause dust pollution. Summary of the Invention

[0008] The purpose of the present invention is to provide a bisphenol A rotary granulation system and method to solve the above deficiencies in the prior art.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A bisphenol A rotary granulation system includes a granulation tower and a nitrogen cooling system for cooling bisphenol A droplets. The nitrogen cooling system includes a nitrogen inlet provided at the bottom of the granulation tower and a nitrogen outlet provided at the top of the granulation tower. In the nitrogen cooling system, the temperature of the nitrogen inlet is between 40°C and 45°C, and the temperature of the nitrogen outlet is between 80°C and 90°C.

[0011] In the above-mentioned bisphenol A rotary granulation system, a rotary granulation barrel is provided in the granulation tower. The rotary granulation barrel includes a conical barrel, and a number of holes are formed on the conical barrel.

[0012] In the above-mentioned bisphenol A rotary granulation system, the conical barrel is a hollow cone with a cone angle of 15° - 30° and a wall thickness of 3 - 7 mm.

[0013] In the above-mentioned bisphenol A rotary granulation system, the aperture size of the holes is 0.7 - 1.1 mm.

[0014] In the above-mentioned bisphenol A rotary granulation system, the height of the granulation tower is between 30 m and 40 m.

[0015] In the above-mentioned bisphenol A rotary granulation system, a partition is formed on the inner wall of the conical barrel along the rotation path of the molten bisphenol A.

[0016] In the above-mentioned bisphenol A rotary granulation system, both the nitrogen inlet and the nitrogen outlet are provided with multiple ones, and the multiple nitrogen inlets and the multiple nitrogen outlets are both annularly distributed.

[0017] In the above-mentioned bisphenol A rotary granulation system, a scraper layer is provided at the bottom of the granulation tower. A scraper plate is rotatably connected to the scraper layer, and there is a gap between the scraper plate and the scraper layer.

[0018] In the above-mentioned bisphenol A rotary granulation system, it further includes a preheating mechanism for heating the conical barrel. The preheating mechanism includes a preheating barrel, and the temperature inside the preheating barrel is controlled between 150°C and 170°C.

[0019] A bisphenol A rotary granulation method, based on the bisphenol A rotary granulation system according to any one of the above, in the granulation tower, the molten bisphenol A from top to bottom exchanges heat with the nitrogen from bottom to top to obtain bisphenol A particles. The temperature of the nitrogen when entering the granulation tower is controlled between 40°C and 45°C, and the temperature of the nitrogen when discharging from the granulation tower is controlled between 80°C and 90°C.

[0020] In the above technical scheme, the present invention provides a bisphenol A rotary granulation system and method, in which, in a granulation tower, nitrogen flows from bottom to top and exchanges heat with bisphenol A droplets, so that the temperature of the nitrogen outlet is greater than the temperature of the nitrogen inlet, and when the nitrogen inlet temperature is controlled between 40°C and 45°C, nitrogen and bisphenol A exchange heat so that the nitrogen outlet temperature is between 80°C and 90°C, so that the temperature of bisphenol A when discharged is controlled between 60°C and 70°C, and the adhesion of bisphenol A particles and the clogging of equipment and pipelines are avoided as much as possible, while the breakage of bisphenol A particles is reduced, and the generation of fine powder is reduced, so that the proportion of fine powder is controlled at about 0.55%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0022] Figure 1 A schematic diagram of the overall structure provided by an embodiment of the present invention;

[0023] Figure 2 A schematic diagram of the structure of a conical barrel and a preheating barrel provided in an embodiment of the present invention.

[0024] Description of reference numerals:

[0025] 1. Granulation tower; 2. Nitrogen inlet; 3. Nitrogen outlet; 4. Conical barrel; 5. Partition; 6. Scraper layer; 7. Scraper plate; 8. Preheating barrel; 9. Steam channel; 10. Purge port. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0027] Reference Figure 1-2 An embodiment of the present invention provides a bisphenol A rotary granulation system, comprising a granulation tower 1 and a nitrogen cooling system for cooling bisphenol A droplets, wherein the nitrogen cooling system comprises a nitrogen inlet 2 arranged at the bottom of the granulation tower 1 and a nitrogen outlet 3 arranged at the top of the granulation tower 1, and in the nitrogen cooling system, the temperature of the nitrogen inlet 2 is between 40°C and 45°C, and the temperature of the nitrogen outlet 3 is between 80°C and 90°C.

[0028] Specifically, the bisphenol A rotary granulation system generally includes a granulation tower 1, a rotary granulation barrel, a nitrogen cooling system, a scraper machine, and a screw conveyor. The rotary granulation barrel is located at the top of the granulation tower 1, and the scraper machine and the screw conveyor are located at the bottom of the granulation tower 1. The nitrogen cooling system is used to introduce low-temperature (relatively lower than the temperature of bisphenol A droplets) nitrogen into the granulation tower 1 to exchange heat with high-temperature (relatively higher than the temperature of nitrogen) bisphenol A droplets, so that the bisphenol A droplets are cooled into particles and fall to the bottom of the granulation tower 1. Subsequently, the bisphenol A particles can be discharged from the granulation tower 1 through the scraper machine and the screw conveyor; the nitrogen cooling system includes a nitrogen inlet 2 and a nitrogen outlet 3. The nitrogen inlet 2 is located at the bottom of the granulation tower 1 to input low-temperature nitrogen into the tower, and the nitrogen outlet 3 is located at the top of the granulation tower 1 to discharge the nitrogen after heat exchange; the above are all prior arts and will not be elaborated here. The innovation of the embodiment of the present invention lies in controlling the temperature of the nitrogen inlet 2 between 40°C and 45°C. After the nitrogen exchanges heat with the bisphenol A droplets, the temperature of the nitrogen outlet 3 is between 80°C and 90°C. In this way, the temperature of the bisphenol A when discharged can be controlled between 60°C and 70°C. At this time, the temperature of the bisphenol A is controlled under the optimal working condition, and the particle size of the bisphenol A particles presents a normal distribution, and the proportion of particles with a particle size of 0.5 mm or less (including 0.5 mm) is about 0.55%. In this way, the generation of fine powder is reduced, the pollution of the environment by the fine powder is reduced, and the safety index of the working environment is effectively improved.

[0029] It should be noted that in each embodiment of the present invention, during the continuous transportation of nitrogen, the temperature will change within a certain range. Therefore, the controlled temperature values are all range values. For example, in the above embodiment, during the production of bisphenol A granulation once, the temperature of the nitrogen inlet 2 (i.e., the inlet temperature) fluctuates between 40°C and 45°C, and the temperature of the nitrogen outlet 3 (i.e., the outlet temperature) fluctuates between 80°C and 90°C. The temperature range of the bisphenol A when discharged from the granulation tower 1 is controlled between 60°C and 70°C, and the normal distribution value of the particle size of the bisphenol A particles can be obtained in this production, and the proportion of particles with a particle size of 0.5 mm or less (including 0.5 mm) is about 0.55%.

[0030] In this embodiment, when preparing bisphenol A particles through the rotary granulation system, while keeping other parameters (parameters such as the cone angle, rotation speed, and circulating nitrogen volume of the rotary granulation barrel) unchanged, nitrogen with different temperatures is introduced into the cooling tower (in one working condition, the inlet temperature and the outlet temperature of the nitrogen both fluctuate within a certain range), and the experimental results shown in the following table are obtained:

[0031]

[0032]

[0033] It is concluded by analyzing the data that, while keeping other parameters unchanged, changing the temperature of the nitrogen inlet 2 so that the nitrogen exchanges heat with the bisphenol A droplets and obtaining the corresponding temperature of the nitrogen outlet 3 can effectively change the particle size distribution of the produced particles; in working condition 1, there are more small particles and more fine powder (particles with a particle size of 0.5 mm and below) in the output; in working condition 3, there are more large particles (particles with a particle size greater than 1.0 mm) in the output, and adhesion is likely to occur; in working condition 2, the temperature of the nitrogen inlet 2 is controlled between 40 °C and 45 °C, and the temperature of the nitrogen outlet 3 is controlled between 80 °C and 90 °C. The obtained particle size of bisphenol A is the most ideal, with the proportion of particles with a particle size of 1.0 mm being greater than 85%, the proportions of large particles and small particles being relatively small, and the proportion of fine powder being about 0.55%.

[0034] Compared with the prior art where the proportion of fine powder is controlled at 1%, the proportion of fine powder in the embodiment of the present invention is reduced by 0.45%. Compared with the overall output of bisphenol A, the difference in their proportions is relatively small (only 0.45% difference). However, when the output of bisphenol A is the same, the weight of fine powder in the embodiment of the present invention is nearly halved compared with the prior art, which greatly reduces the dust pollution in the cooling tower.

[0035] In a further embodiment provided by the present invention, the granulation tower 1 is provided with a rotating granulation barrel. The rotating granulation barrel includes a conical barrel 4, and a number of holes are formed on the conical barrel 4. The conical barrel 4 is a hollow cone with a cone angle of 15° - 30° and a wall thickness of 3 - 7 mm. The aperture size of the holes is 0.7 - 1.1 mm. Specifically, the rotating granulation barrel is arranged at the top of the granulation tower 1, and a driving mechanism is arranged in the granulation tower 1 to drive the conical barrel 4 to rotate. The driving mechanism can be a motor structure in the prior art (not shown and not elaborated) to drive the conical barrel 4 to rotate at the top of the granulation tower 1. The conical barrel 4 is arranged in an inverted conical shape, and a feed inlet is formed at its top. The bisphenol A solution is discharged into the conical barrel 4 through the feed inlet, and then the molten bisphenol A is ejected from a number of holes in a spiral shape by the centrifugal force generated by the rotation of the conical barrel 4 and then gradually breaks into droplets under the action of gravity (the molten bisphenol A is in a linear shape when it just ejects from the holes). When the droplets fall, they exchange heat with the upward nitrogen cold flow and solidify into bisphenol A particles.

[0036] In each embodiment of the present invention, the diameter of the granulation tower 1 can be matched according to the production capacity. For a production capacity of 120,000 tons, the diameter of the granulation tower 1 is 9m - 11m, and for a production capacity of 240,000 tons, the diameter of the granulation tower 1 is 12m - 14m; the height of the granulation tower 1 is between 30m and 40m. The conical barrel 4 can select a cone angle within the range of 15° - 30° according to the working conditions, and the number of holes can be selected between 3000 and 10000 according to the working conditions. The rotation speed of the conical barrel 4 is controlled at 120 - 220 r / min. In this way, it can ensure that the droplets ejected from each hole do not cross-collide and that the droplets do not collide with the inner wall of the granulation tower 1, thereby reducing the probability of particle breakage and further reducing the proportion of fine powder.

[0037] Preferably, a partition 5 is constructed on the inner wall of the conical barrel 4 at the rotation stroke of the molten bisphenol A. Specifically, a plurality of partitions 5 are evenly arranged on the inner wall of the conical barrel 4. When the conical barrel 4 rotates, the conical barrel tends to drive the molten bisphenol A to rotate. At this time, the plurality of partitions 5 can block the rotation of the molten bisphenol A in the conical barrel and prevent it from being discharged through the holes, and try to avoid the formation of vortices of the molten bisphenol A in the barrel, ensuring that the molten bisphenol A is ejected from each hole.

[0038] Furthermore, a plurality of nitrogen inlets 2 and nitrogen outlets 3 are provided. The plurality of nitrogen inlets 2 and the plurality of nitrogen outlets 3 are both annularly distributed. Specifically, the plurality of nitrogen inlets 2 are located at the bottom of the granulation tower 1 and are evenly arranged along the circumference of the granulation tower 1, and the plurality of nitrogen outlets 3 are located at the top of the granulation tower 1 and are evenly arranged along the circumference of the granulation tower 1; with this setting, the nitrogen flow field distribution in the granulation tower 1 is more uniform and stable, reducing particle breakage caused by turbulence and convective collisions, and effectively avoiding nitrogen from disturbing the spiral falling trajectory of the droplets.

[0039] In the nitrogen cooling system, the nitrogen flow rate is controlled between 0.3m / s and 1.1m / s. Specifically, the molten bisphenol A is ejected from the conical barrel 4 and undergoes processes such as jet flow, flow interruption, crystal nucleus formation, crystallization, and forming. During this process, the circulating nitrogen volume, flow rate, and flow pattern distribution directly affect the final particle size distribution and dust amount. In each embodiment of the present invention, the nitrogen flow rate is controlled between 0.3m / s and 1.1m / s, and the nitrogen circulation volume is matched according to the production capacity. For a production capacity of 120,000 tons, it corresponds to 8×104 Nm 3 / h - 12×104 Nm 3 / h, and for a production capacity of 240,000 tons, it corresponds to 16×104 Nm 3 / h - 22×104 Nm 3 / h.

[0040] In another embodiment provided by the present invention, further, a scraper layer 6 is provided at the bottom of the granulation tower 1, a scraper plate 7 is rotatably connected to the scraper layer 6, and a gap is provided between the scraper plate 7 and the scraper layer 6. Specifically, the scraper layer 6 is located on the bottom wall of the granulation tower 1, which is used to receive the solidified bisphenol A particles. A screw conveyor (this is prior art, not shown and not elaborated here) is also provided at the bottom of the granulation tower 1. When the scraper plate 7 rotates on the scraper layer 6, it can push the bisphenol A particles to the inlet of the screw conveyor, thereby discharging the bisphenol A from the granulation tower 1; in this embodiment, the scraper plate 7 is formed by surfacing with wear-resistant materials, and a certain gap is maintained between the scraper plate 7 and the scraper layer 6. When the scraper machine scrapes and conveys the bisphenol A particles, a soft push between the bisphenol A particles is presented, which will not cause the bisphenol A particles to break, maintaining the integrity of the particles and effectively reducing the formation of fine dust.

[0041] Preferably, a plurality of temperature monitoring mechanisms are provided in the granulation tower 1. Specifically, the temperature monitoring mechanism can be an infrared temperature sensor in the prior art. The plurality of temperature monitoring mechanisms are respectively installed at different positions of the granulation tower 1 to monitor the temperatures of the nitrogen inlet 2, the nitrogen outlet 3, the bisphenol A inlet and the bisphenol A outlet, so as to facilitate adjustment according to the working conditions.

[0042] In still another embodiment provided by the present invention, a preheating mechanism for heating the conical barrel 4 is further included. The preheating mechanism includes a preheating barrel 8, and the temperature inside the preheating barrel 8 is controlled between 150°C and 170°C. Specifically, a steam channel 9 is provided inside the preheating barrel 8 to introduce high-temperature steam into the preheating barrel 8. Preferably, the temperature inside the preheating barrel 8 is controlled between 150°C and 170°C. In this embodiment, a lifting mechanism is provided inside the granulation tower 1 to drive the conical barrel 4 to move up and down relative to the preheating barrel 8. The lifting mechanism can be a cylinder or a hydraulic cylinder structure in the prior art to drive the conical barrel 4 to move out of or into the preheating barrel 8 relative to the preheating barrel 8 (the lifting mechanism is a prior art and is not shown and will not be elaborated here). In the prior art, a preheating mechanism is generally not provided on the granulation tower 1, or the preheating temperature is relatively low (such as 70°C to 90°C). After the conical barrel 4 is replaced, the temperature inside the conical barrel 4 is relatively low, and the molten bisphenol A entering the replaced conical barrel 4 will solidify and block the holes, which will cause the molten bisphenol A inside the conical barrel 4 to overflow from the feed port. The overflow time is generally as long as 5 - 6 minutes until the bisphenol A inside the conical barrel 4 melts again and is discharged through the holes, and then the overflow ends. In this embodiment, the temperature inside the preheating barrel 8 is controlled between 150°C and 170°C. After the conical barrel 4 is replaced, the conical barrel 4 is moved into the preheating barrel 8 relative to the preheating barrel 8 through the lifting mechanism to heat the conical barrel 4 and bisphenol A through the preheating barrel 8, thereby controlling the overflow time within 1 minute (after the temperature inside the conical barrel 4 increases, the bisphenol A is converted from a solidified state to a molten state again, effectively preventing the bisphenol A from crystallizing and caking), greatly reducing the impact of overflow on the granulation process and reducing material loss. Preferably, a purge port 10 can be provided on the steam channel 9, and an electrically controlled valve can be provided at the purge port 10 (the electrically controlled valve is a prior art and will not be elaborated here). After the conical barrel 4 is replaced, opening the purge port 10 can purge the conical barrel 4, so that the overflow time can be further reduced.

[0043] In still another embodiment of the present invention, a method for rotating granulation of bisphenol A is provided. Based on the bisphenol A rotating granulation system of any one of the above, in the granulation tower, the molten bisphenol A from top to bottom exchanges heat with the nitrogen from bottom to top to obtain bisphenol A particles. The temperature of the nitrogen entering the granulation tower is controlled between 40°C and 45°C, and the temperature of the nitrogen discharged from the granulation tower is controlled between 80°C and 90°C to minimize the dust pollution in the granulation tower.

[0044] Only some exemplary embodiments of the present invention have been described by way of illustration above. Undoubtedly, for those of ordinary skill in the art, without departing from the spirit and scope of the present invention, the described embodiments can be modified in various different ways. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A bisphenol A rotary granulation system, comprising a granulation tower and a nitrogen cooling system for cooling bisphenol A droplets, wherein the nitrogen cooling system comprises a nitrogen inlet disposed at the bottom of the granulation tower and a nitrogen outlet disposed at the top of the granulation tower, characterized in that: In the nitrogen cooling system, the nitrogen inlet temperature is between 40°C and 45°C, and the nitrogen outlet temperature is between 80°C and 90°C.

2. A bisphenol A rotary granulation system according to claim 1, characterized in that: A rotary granulation barrel is arranged in the granulation tower, and the rotary granulation barrel comprises a conical barrel, and a plurality of holes are configured on the conical barrel.

3. A bisphenol A rotary granulation system according to claim 2, characterized in that: The conical barrel is a hollow cone with a cone angle of 15°-30° and a wall thickness of 3-7 mm.

4. A bisphenol A rotary granulation system according to claim 2, characterized in that: The hole has a diameter of 0.7-1.1 mm.

5. A bisphenol A rotary granulation system according to claim 1, characterized in that: The height of the granulation tower is between 30m and 40m.

6. A bisphenol A rotary granulation system according to claim 2, characterized in that: The inner wall of the conical barrel is configured with a partition located on the rotation path of the molten bisphenol A.

7. A bisphenol A rotary granulation system according to claim 1, characterized in that: A plurality of nitrogen inlets and a plurality of nitrogen outlets are provided, and the plurality of nitrogen inlets and the plurality of nitrogen outlets are distributed in a ring shape.

8. A bisphenol A rotary granulation system according to claim 1, characterized in that: A scraper layer is arranged at the bottom of the granulation tower, a scraper plate is rotatably connected to the scraper layer, and a gap is provided between the scraper plate and the scraper layer.

9. A bisphenol A rotary granulation system according to claim 2, characterized in that: It also includes a preheating mechanism for heating the conical barrel, wherein the preheating mechanism includes a preheating barrel, and the temperature in the preheating barrel is controlled between 150°C and 170°C.

10. A bisphenol A rotary granulation method, based on the bisphenol A rotary granulation system according to any one of claims 1 to 9, wherein in a granulation tower, molten bisphenol A from top to bottom is heat exchanged with nitrogen from bottom to top to obtain bisphenol A particles, characterized in that: The temperature of the nitrogen when entering the granulation tower is controlled between 40°C and 45°C, and the temperature of the nitrogen when leaving the granulation tower is controlled between 80°C and 90°C.

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