Spray granulation drying device

Abstract

The utility model relates to the technical field of granulation devices, and mainly discloses a spray granulation drying device which comprises a settling section, a granulation section, a drying section and a bottom air chamber which are sequentially arranged from top to bottom, an air inlet is formed in the side portion of the air chamber and communicated with the drying section through an inclined air distribution plate, and two-fluid atomization spray guns which are vertically upward are evenly distributed in the drying section in the circumferential direction. The tail end of the spray gun is provided with a compressed air and raw material liquid inlet, the granulation section adopts a conical structure of which the sectional area is gradually expanded from bottom to top, and is matched with the design that the air distribution plate is inclined towards the feed opening, so that the uniform distribution of a fluidized material layer and the gravity self-outflow of finished product particles are realized. The reverse spraying layout of the spray gun is combined, so that liquid drop penetration and wall sticking are reduced, the problems of non-uniform air distribution, out-of-control particle size, high energy consumption and the like of traditional equipment are solved, and the granulation efficiency and the particle uniformity are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a spray granulation drying device. BACKGROUND

[0002] The spray granulation drying equipment is the equipment that liquid material is formed into mist drop through spraying, then utilizes hot air to dry, makes it form granular product. The spray granulation drying equipment is divided into continuous type and intermittent type according to operating mode, and the material is continuously entered and continuously discharged in the continuous type spray granulation drying equipment, and it is suitable for large-scale, continuous production. In the intermittent spray granulation drying, the material is added in batches, and the next batch is carried out after each batch of material is treated.

[0003] The spray granulation drying equipment is the key equipment of industrialized production granular material, and the existing continuous type granulation drying equipment adopts rectangular horizontal multi-air chamber layout, adjusts the hot air flow state through multiple independent air chambers to realize continuous production. Although this technology is widely used, there are still the following significant defects in actual operation:

[0004] 1. The multiple air chamber adjustment is complex, and the operation stability is poor. The existing device needs to adjust the air door opening degree of each air chamber accurately to maintain the fluidization state, and the dependence on the experience of the operator is high. Improper adjustment can easily lead to local dead bed or uneven fluidization, and the dead bed shutdown rate is high during the start-up stage, which seriously restricts the continuous production efficiency and equipment reliability.

[0005] 2. The air distribution plate opening rate design defect causes difficult discharge control. To adapt to the long-span characteristics of the horizontal structure, the air distribution plate usually adopts combined design of inclined holes and straight holes, but due to the difficulty in dynamically matching the material layer change, it is easy to cause the discharge speed out of control, the material layer to be stacked too high, and finally to cause the fluidization to be interrupted and the dead bed.

[0006] 3. The particle size of the discharged material is uneven, and the invalid energy consumption is prominent. The unilateral layout of the discharge port leads to a wide range of particle distribution, and the large particles need to be crushed and re-granulated after being returned. This process increases invalid energy consumption, and the surface of the crushed particles is rough, and repeated drying leads to a decrease in true density.

[0007] 4. The particles are repeatedly coated, and the oversized particles are formed. When the spray guns are uniformly arranged on both sides of the fluidized bed with a large span, the particles at the far end will be coated with mist droplets again during the flow to the discharge end, resulting in particle size exceeding the target range, further increasing the amount of returned material and energy consumption.

[0008] 5. The structure defect of the air distribution plate leads to low energy efficiency. The inclined hole design interferes with the void fraction of the fluidized bed, so that the dynamic pressure of the spray gun mist droplets exceeds the critical value, and part of the droplets penetrate the material layer and adhere to the side wall to form clumps. The clumps fall off, destroy the fluidization stability, and at the same time, the fine powder not involved in the granulation escapes with the tail gas, causing effective heat energy loss.

[0009] The prior art has core problems of complex operation, high energy consumption, uneven particle size and poor equipment stability due to structural design limitations, and a new type of granulating and drying device is urgently needed to realize efficient, stable and low-energy continuous production. Some continuous granulating and drying equipment in the prior art adopts a single air chamber vertical layout to appropriately solve the above technical problems. However, the existing vertical single air chamber spray granulating equipment still has the following technical problems when used for spray granulation of calcium chloride:

[0010] 1. The existing equipment spray gun is mostly vertically downward or randomly distributed, the atomized liquid droplet dynamic pressure is too high, and the liquid droplets adhere to the side wall of the equipment after penetrating the material layer, resulting in particle caking; the vertically downward sprayed liquid droplets are easily carried away by hot air to form dust, causing ineffective drying. The spray distribution of the spray gun is not matched with the void ratio of the fluidized material layer, and the liquid droplets cannot uniformly coat the surface of the particles, resulting in uneven particle size.

[0011] 2. The cross-sectional area of the existing single air chamber granulating equipment is constant, and a reasonable wind speed gradient distribution is not formed, and the formed particles repeatedly rise and fall in the granulating section due to the unreasonable wind speed gradient, resulting in uneven particle size and excessive drying of the surface of the particles, causing the particles to crack; at the same time, the dust cannot be effectively settled, the dust content in the tail gas is high, and the heat energy is wasted seriously.

[0012] The existing single air chamber vertical equipment also has the problems of high caking rate, poor dust control, energy waste and uneven particle size due to unreasonable spray gun layout and unreasonable configuration of the granulating section structure parameters, and it is difficult to meet the continuous and efficient production requirements of calcium chloride and other materials. Practical new type

[0013] The purpose of the present application is to solve the technical problems existing in the prior art, and to provide a spray granulating and drying device.

[0014] To achieve the above-mentioned purpose, the present application adopts the following technical scheme: a spray granulating and drying device, comprising an air chamber, a drying section, a granulating section and a settling section, the settling section, the granulating section and the drying section are sequentially arranged from top to bottom, the air chamber is arranged at the bottom of the drying section, one side of the air chamber is provided with an air inlet for introducing hot air, a wind distribution plate is arranged between the air chamber and the drying section, the wind distribution plate is uniformly provided with openings for uniformly introducing hot air into the drying section, the bottom of the drying section is provided with a discharge pipe, the upper opening of the discharge pipe is in communication with the internal cavity of the drying section, and the bottom of the discharge pipe extends outside the air chamber, a plurality of uniformly distributed spray guns with a vertical upward spray direction are arranged in the drying section, one side of the top of the settling section is provided with an air outlet, and the settling section is located at the uppermost part of the fluidized bed, the cross-sectional area of the drying section is constant, the cross-sectional area of the granulating section gradually increases from bottom to top, and the cross-sectional area of the settling section is constant.

[0015] The further scheme of the utility model lies in: the fluidization speed of the granulating section is 2.6 m / s~3.1 m / s, the taper of the granulating section is 44-45 degrees, and the reasonable taper ensures that the bulk density of calcium chloride is greater than that of calcium chloride, so that calcium chloride does not accumulate at this place; the static material layer thickness of the granulating section is 0.4 m~0.6 m, the porosity of the material layer under the fluidization state is 0.5~0.6, the opening rate of the air distribution plate is 13%~16%, and the spray gun uses two-fluid atomization, and the atomization compressed air pressure is greater than the centrifugal pump outlet pressure by about 4 kg±0.5 / cm².

[0016] The spray gun comprises a spray pipe and a nozzle, the spray pipe penetrates the pipe wall of the drying section, the end of the spray pipe located at the inner end of the drying section is provided with the nozzle, and the end of the spray pipe located at the outside of the drying section is provided with a compressed air inlet and a raw material liquid inlet.

[0017] In the case of increased production, the diameter of the air distribution plate is increased, and in order to ensure that the drying particles around the air distribution plate can be smoothly discharged, two measures are taken.

[0018] The further scheme of the utility model lies in: the air distribution plate is inclinedly arranged at the discharge opening along the circumference of the drying section, and preferably, the inclination angle is 2~5 degrees. The air distribution plate is designed with a certain taper, so that the finished product particles around the air distribution plate can more easily reach the discharge opening, and smooth discharge is ensured.

[0019] As an alternative scheme of the above scheme, in order to adapt to greater production, a plurality of discharge pipes are arranged, and the plurality of discharge pipes are uniformly distributed on the air distribution plate. The finished product particles are discharged in multiple stages.

[0020] The further scheme of the utility model lies in: the upper and lower sides of the air distribution plate are respectively provided with waterproof asbestos pads.

[0021] The further scheme of the utility model lies in: a liquid pocket and a steam pocket are arranged at the drying section, which are similar to pressure equalizing boxes, and the raw material liquid and compressed air are uniformly distributed after passing through the device.

[0022] The further scheme of the utility model lies in: a plurality of observation openings are uniformly arranged on the pipe wall of the drying section, and preferably, the observation openings are provided with 4 observation openings.

[0023] The further scheme of the utility model lies in: a blowdown opening is arranged at the bottom of the air chamber, and waste water is discharged after the fluidized bed is flushed.

[0024] The further scheme of the utility model lies in: pressure measuring openings are arranged on the drying section and the settling section, which are used for installing pressure sensors to measure the pressure of each part.

[0025] The further scheme of the utility model lies in: temperature measuring openings are arranged at the air inlet, the air outlet and the drying section, which are used for installing temperature sensors to measure the temperature of each part.

[0026] Compared with the prior art, the present application has the advantages of:

[0027] (1) The device adopts a single air chamber design, a cloth air distribution plate is arranged at the lower part, hot air blows the seed crystal into a fluidized state through the cloth air distribution plate, a stable material layer is formed, the drying section of the device is in a conical shape as a whole, a certain straight section is arranged at the lower end as a drying section, the cross section above the drying section is continuously increased, the wind speed is reduced, and the particles are continuously coated and grown, and are settled to the lower end drying section under the action of gravity, the finished product particles after drying are discharged from the discharge port, the conical cylinder body is used to uniformly reduce the wind speed from the lower end to the upper end, so that the distribution of the particles in the fluidized state is gradually reduced from the drying section to the granulation section. The discharge port of the device is arranged at the bottom of the fluidized bed and connected with the cloth air distribution plate, the discharge position is not blown by air, and therefore the finished product in the fluidized state around the drying section flows down from the discharge port under the action of gravity, the particle size of the finished product particles is more uniform, and the content of small particles and powder is reduced.

[0028] (2) The spray gun adopts two-fluid atomization, small liquid droplets distributed between the particles after compressed air atomization continuously coat and adhere, slowly grow and settle to the bottom, and the surface of the particles is smooth due to the severe friction, the compressed air atomization is used for the nozzle, good atomization effect can be achieved under the condition of low pressure, the dynamic pressure of the sprayed liquid droplets is low, it is not easy to penetrate the material layer to generate fine powder, the dust in the tail gas is low, and the wall sticking is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0030] Figure 1 It is a front view of the spray granulation drying device of the present application.

[0031] Figure 2 It is a side view of the spray granulation drying device of the present application.

[0032] Figure 3 It is a schematic view of the spray gun structure of the spray granulation drying device of the present application.

[0033] Figure 4 It is a schematic view of the cloth air distribution plate structure of the spray granulation drying device of the present application.

[0034] Figure 5 It is a schematic view of the inclination angle of the cloth air distribution plate of the spray granulation drying device of the present application.

[0035] In the diagram: 1. Air chamber; 2. Drying section; 3. Granulation section; 4. Settling section; 5. Air inlet; 6. Feed pipe; 7. Air distribution plate; 8. Spray gun; 9. Air outlet; 10. Waterproof asbestos pad; 11. Liquid tank; 12. Steam tank; 13. Observation port; 14. Drain outlet; 15. Temperature measuring port; 16. Pressure measuring port; 17. Compressed air inlet; 18. Raw material liquid inlet. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] like Figure 1 As shown, a spray granulation drying device includes an air chamber 1, a drying section 2, a granulation section 3, and a settling section 4, wherein the settling section 4, the granulation section 3, and the drying section 2 are arranged sequentially from top to bottom.

[0038] The air chamber 1 is located at the bottom of the drying section 2. An air inlet 5 for hot air is located on one side of the air chamber 1. An air distribution plate 7 is located between the air chamber 1 and the drying section 2. The air distribution plate 7 has evenly distributed openings to allow hot air to be uniformly introduced into the drying section 2. A feed pipe 6 is located at the bottom of the drying section 2. The upper opening of the feed pipe 6 is connected to the internal cavity of the drying section 2, and the bottom of the feed pipe 6 extends outside the air chamber 1. In this device, the feed pipe 6 is located at the bottom of the fluidized bed and connected to the air distribution plate 7. There is no air blowing at the feed position, so the finished product, which is in a fluidized state after drying, flows down from the feed pipe 6 under gravity. The fluidization velocity in the drying section 2 is high, and the hot air blows small particles and dust to the granulation section 3 above, reducing the particle distribution range during the drying process, resulting in more uniform particle size at the output; the amount of returned material is lower, reducing ineffective energy consumption.

[0039] An air outlet 9 is provided on one side of the top of the settling section 4, and the settling section 4 is located at the top of the fluidized bed.

[0040] Settling section 4 is located at the top of the fluidized bed, where the interface is largest, the wind speed is slowest, and the moisture content of the exhaust gas is highest. Because spray gun 8 cannot penetrate the fluidized bed, only some small dust particles generated by the intense flow and friction of the particles collide and stick together here. Some of these particles grow larger and settle to granulation section 3 for re-granulation, while a small portion of the dust is carried away by the exhaust gas and enters the subsequent dust removal process.

[0041] The utility model discloses a single air chamber design, hot air enters the air warehouse buffer and enters drying tower drying section 2 through the bed cloth wind board 7, the design of single air chamber 1 makes the whole device not need to adjust the air pressure of cloth wind board 7 each position, more easily the laying of material layer in the device start stage, the air door adjustment is reduced in the process of simultaneous operation, and it is more simple and efficient, and the air inlet wind speed is 15-20m / s, controls the pipeline resistance.

[0042] As shown in Figure 1 The drying section 2 is provided with a plurality of spray guns 8 with uniform distribution and vertical upward spraying direction, the spray gun 8 comprises a spray pipe and a nozzle, the spray pipe penetrates the pipe wall of the drying section 2, the end portion of the spray pipe located in the inner end of the drying section 2 is provided with the nozzle, and the end portion of the spray pipe located outside the drying section 2 is provided with a compressed air inlet 17 and a raw material liquid inlet 18.

[0043] The spray gun 8 uses two-fluid atomization, and the atomization compressed air pressure is greater than the centrifugal pump outlet pressure by about 4kg±0.5 / cm². 2 This design ensures the atomization effect, the atomized material liquid has low kinetic energy, is always in the material layer with a porosity of 0.5-0.6, continuously coats and dries the flowing particles without penetrating the material layer, and reduces wall sticking and dusting.

[0044] The finer atomized particle size makes the granulating mechanism tend to be coating, the particle surface is smoother, and the particle true density and bulk density are higher, compared with traditional pressure atomization agglomeration granulation. The spray gun 8 is uniformly arranged around the device, sprays from bottom to top, continuously coats and dries the particles in the descending process, does not appear the repeated drying process of the square fluidized bed, and has higher drying efficiency.

[0045] The drying section 2 has constant cross-sectional area, the granulating section 3 has gradually increasing cross-sectional area from bottom to top, and the settling section 4 has constant cross-sectional area. The cross-sectional area of the granulating section 3 above the cloth wind board 7 increases in turn, the interface wind speed decreases in turn, with the fluidization, the increased large particles in the granulating section 3 naturally settle to the bottom drying section 2 of the device, and are discharged through the discharge pipe 6 after drying in the drying section 2.

[0046] The fluidization speed of the granulating section 3 is 2.6m / s~3.1m / s, the cross-sectional area increasing rate of the granulating section 3 is 10%~15%, the static material layer thickness of the granulating section 3 is 0.4mm~0.6mm, the porosity of the material layer in the fluidization state is 0.5~0.6, and the opening rate of the cloth wind board 7 is 13%~16%.

[0047] The key difference between this utility model and the existing single-chamber granulation device lies in the elimination of the built-in heater. Low-temperature and high-efficiency drying (exhaust gas temperature 150-170℃) is achieved through the coordinated control of the fluidization velocity gradient of the single-chamber 1 and the dynamic pressure of the spray gun 8. It is especially suitable for granulation of heat-sensitive materials such as calcium chloride. Because the main structure of this device is circular, the fluidizing air has only one direction from top to bottom. The size of the opening ratio only affects the thickness of the material layer and does not affect the discharge direction. A lower opening ratio can be used. During operation, the output is controlled by controlling the thickness of the material layer, which is convenient to operate.

[0048] With increased production, the diameter of the air distribution plate 7 increases. To ensure smooth feeding of dried particles from all sides, two measures are taken:

[0049] A further aspect of this utility model is: Figure 5 As shown, the air distribution plate 7 is inclined towards the feed inlet along the circumference of the drying section 2. Preferably, the inclination angle is 2~5°. The air distribution plate 7 is designed with a certain taper so that the finished particles around it can more easily reach the feed inlet, ensuring smooth discharge.

[0050] As an alternative to the above solution, to accommodate a larger output, multiple feed pipes 6 are provided, and these multiple feed pipes 6 are evenly distributed on the air distribution plate 7. This allows the finished granules to flow out in segments and through multiple channels.

[0051] A further aspect of this utility model is: Figure 4 As shown, waterproof asbestos pads 10 are respectively provided on the upper and lower sides of the air distribution plate 7.

[0052] like Figure 2 As shown, the drying section 2 is equipped with a liquid tank 11 and a steam tank 12, similar to an equalizing chamber. The raw material liquid and compressed air are evenly distributed after passing through this device.

[0053] like Figure 1 As shown, the tube wall of the drying section 2 is evenly distributed with a plurality of observation ports 13, preferably, there are 4 observation ports 13.

[0054] The bottom of the air chamber 1 is provided with a drain outlet 14 to discharge wastewater after rinsing the fluidized bed.

[0055] The drying section 2 and settling section 4 are equipped with pressure measuring ports 16 for installing pressure sensors to measure the pressure at each part.

[0056] Temperature measuring ports 15 are provided at the air inlet 5, air outlet 9 and drying section 2 for installing temperature sensors to measure the temperature of each part.

[0057] The other advantage of the utility model lies in: the device is designed in countercurrent mode, the drying section 2 is located at the lowermost position, compared with the traditional fluidized bed, the drying and granulation process is clear in boundary. The drying effect and particle distribution are guaranteed. In actual operation, the traditional fluidized bed needs to control the qualified product output at a temperature of about 180-200 DEG C, the device can control the tail gas at 150-170 DEG C and run stably. The arrangement volume of the circular single air chamber 1 is smaller, for example, 2T / H, the diameter of the fluidized section of the circular fluidized bed is 2.2 meters, the square fluidized bed needs 0.75*6m, and the land area occupied by the device is smaller.

[0058] The granulation and drying process for producing calcium chloride by using the device is as follows:

[0059] S1. The 1-2mm seed particles are put into the drying section 2 above the air distribution plate 7 by using the spray granulation and drying equipment, the static layer height is 0.4-0.6mm after laying,

[0060] S2. The hot air with a temperature of 400-450 DEG C is introduced into the air chamber 1, the hot air inlet speed is 15-20m / s, the seed particles are blown into fluidized state by the hot air through the air distribution plate 7, the fluidized speed is controlled to be 2.6~3.1m / s, the stable layer is formed, and the porosity of the stable layer in the fluidized state is 0.5-0.6;

[0061] S3. The calcium chloride solution is sprayed upwards from bottom to top by using the spray gun 8, the atomized compressed air pressure is higher than the solution pump pressure by 4kg±0.5 / cm²;

[0062] S4. With the continuous coating and growth of the particles, the particles are settled to the lower drying section 2 under the action of gravity, and the finished product particles are discharged from the discharge port after drying;

[0063] S5. Only a part of the small dust generated by the intense flow friction of the particles in the settling section 4 is removed by collision and adhesion, a part of the particles is settled to the granulation section 3 for re-granulation, and a small part of the dust is taken away by the tail gas and enters the subsequent dust removal process.

[0064] Because the main structure of the device is circular, the fluidization air has only one direction from top to bottom, the size of the opening rate only affects the layer thickness and does not affect the discharge direction, the opening rate can be relatively low, and the yield can be controlled by controlling the layer thickness during operation. It is convenient to operate.

[0065] The spray gun uses two-fluid atomization, the lift of the ordinary centrifugal pump is 30m, and the atomized compressed air pressure is greater than the outlet pressure of the centrifugal pump by about 4kg / cm 2 , under the condition of ensuring the atomization effect, the kinetic energy of the atomized liquid is low, and the atomized liquid is always inside the layer with a porosity of 0.5-0.6, cannot penetrate the layer and reduces the wall sticking and dust raising.

[0066] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the application can be implemented in other particular forms without departing from the spirit or essential characteristics of the application. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims shall be construed as limiting the scope of the claims.

Claims

1. A spray granulation drying apparatus characterized by: The utility model relates to a kind of drying device, including air chamber (1), drying section (2), granulation section (3) and settling section (4), the settling section (4), granulation section (3), drying section (2) are sequentially arranged from top to bottom, the air chamber (1) is arranged at the bottom of drying section (2), one side of the air chamber (1) is provided with air inlet (5) for passing into hot air, air distribution plate (7) is arranged between the air chamber (1) and drying section (2), air distribution plate (7) is uniformly provided with opening, the bottom of drying section (2) is provided with discharge pipe (6), a plurality of spray guns (8) are arranged in drying section (2), the spray guns (8) are uniformly distributed and the spray direction is perpendicular to upwards, the top of the settling section (4) one side is provided with air outlet (9), the cross-sectional area of the granulation section (3) gradually increases from bottom to top, the cross-sectional area of the settling section (4) is constant, liquid package (11) and steam pocket (12) are arranged at drying section (2), a plurality of observation ports (13) are uniformly distributed on the pipe wall of drying section (2), the bottom of the air chamber (1) is provided with blowdown port (14), pressure measuring port (16) is arranged on drying section (2) and settling section (4), temperature measuring port (15) is arranged at air inlet (5), air outlet (9) and drying section (2).

2. A spray granulation drying apparatus according to claim 1, wherein: The spray gun (8) includes spray pipe and nozzle, the spray pipe passes through the pipe wall of drying section (2), the nozzle is arranged at the end of spray pipe in drying section (2), and compressed air inlet (17) and raw material liquid inlet (18) are arranged at the end of spray pipe outside drying section (2).

3. A spray granulation drying apparatus according to claim 2, wherein: The spray gun is a two-fluid atomizing spray gun.

4. A spray granulation drying apparatus according to claim 1, wherein: The air distribution plate (7) is inclinedly arranged along the circumference of drying section (2) to the discharge port.

5. A spray granulation drying apparatus according to claim 4, wherein: The inclination angle of the air distribution plate (7) is 2-5°.

6. A spray granulation drying apparatus according to claim 1, wherein: The discharge pipe (6) is provided with a plurality of discharge pipes (6), and the plurality of discharge pipes (6) are uniformly distributed on the air distribution plate (7).

7. A spray granulation drying apparatus according to claim 5, wherein: Waterproof asbestos pads (10) are arranged on the upper and lower sides of the air distribution plate (7).

8. A spray granulation drying apparatus according to claim 1, wherein: The observation port is provided with four observation ports.

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