A magnesium chloride granulation and drying integrated system and method

Abstract

The present invention discloses a magnesium chloride granulation and drying integrated system and method, including a granulation and drying integrated machine and a magnesium chloride spray device, the granulation and drying integrated machine includes a granulation zone and a fluidized section connected, the granulation zone is located above the fluidized section, a discharge port is arranged at one end of the fluidized section, the granulation zone is connected to the magnesium chloride spray device, the discharge port and the magnesium chloride spray device are located on the same side of the granulation and drying integrated machine, a cooling air chamber and a drying air chamber are arranged below the granulation and drying integrated machine, the cooling air chamber outlet is connected to the granulation zone, and the drying air chamber outlet is connected to the fluidized section, wherein the cooling air chamber outlet is located at one end away from the magnesium chloride spray device, and the drying air chamber outlet is located at one end close to the discharge port. The spray granulation of magnesium chloride brine and the drying process of magnesium chloride particles are integrated in one device, the device has a high degree of integration, reduces the number of equipment, material transfer links and equipment failure points, and improves production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium chloride granulation, and in particular to a magnesium chloride granulation and drying integrated system and method. Background Art

[0002] Magnesium chloride is an important inorganic raw material in the chemical industry. It is used to produce magnesium products such as magnesium carbonate, magnesium hydroxide, magnesium oxide, and is also used as a raw material for antifreeze.

[0003] The existing process for manufacturing magnesium chloride particles is mainly as follows: Figure 5 The spray granulation is carried out in a spray tower and the drying is carried out as shown. Figure 6 The spray granulation is performed in the granulation and drying integrated machine as shown; Figure 5 When the equipment shown is used to produce magnesium chloride particles, 50% magnesium chloride brine is granulated by high-speed rotation of the atomizer 24 in the spray tower, and hot air is provided by a high-temperature flue gas furnace (using combustion of natural gas, petroleum gas, etc. as a heat source) to enter the spray tower to dry the droplets of the magnesium chloride solution. The droplets formed by the high-speed rotation of the atomizer are dried into magnesium chloride particles, and then enter the cyclone dust collector 25 and the electrostatic precipitator 26 for particle collection through the suction of the induced draft fan 27 to obtain magnesium chloride particles. The process is characterized by a simple process, and granulation and drying are both carried out in the spray tower. However, since it takes a lot of heat and a long drying process to dry the 50% magnesium chloride hexahydrate brine into magnesium chloride dihydrate particles, and since granulation and drying are both in the spray tower, the production capacity is very low; Figure 6 When the equipment shown produces magnesium chloride particles, 50% magnesium chloride brine enters the fluidized bed 29 through a pressure or compressed air atomizer 28, and hot air is heated to about 100-170°C through an electric heater 30 and enters the fluidized bed 29. The solution droplets and the hot air carry out convection heat and mass transfer in the fluidized bed 29 to dry the droplets. The droplets cannot form particles directly, and it is necessary to pre-spread a small-diameter granular base material in the fluidized bed as a seed crystal. Through the spraying, coating and drying of the droplets, the seed crystals of the base material are continuously grown and dried to form large-particle finished materials. Since the base material needs to be spread in the fluidized bed and the base material crystal is grown by coating the solution spray droplets, the accuracy of the system operation is high, and the control requirements for time and temperature are also very high, resulting in complex system operation.

[0004] Although the magnesium chloride particles prepared by the above two methods meet the product quality requirements, they are complex processes, require more equipment, have more control points and require higher operating requirements, which can easily cause process shutdowns and equipment damage, and have many equipment failure points and require more maintenance. Summary of the invention

[0005] In order to solve the above problems, the present disclosure proposes an integrated system and method for magnesium chloride granulation and drying, which integrates the spray granulation of magnesium chloride brine and the drying process of magnesium chloride particles in one device. The device has a high degree of integration, reduces the number of devices, material transfer links and equipment failure points, reduces operating costs, and improves production efficiency.

[0006] To achieve the above objectives, the present disclosure adopts the following technical solutions:

[0007] In the first aspect, a magnesium chloride granulation and drying integrated system is proposed, including a granulation and drying integrated machine and a magnesium chloride spray device, the granulation and drying integrated machine includes a granulation zone and a fluidizing section, the granulation zone is located above the fluidizing section, a discharge port is arranged at one end of the fluidizing section, the granulation zone is connected with the magnesium chloride spray device, a cooling air chamber and a drying air chamber are arranged below the fluidizing section, the air outlet of the cooling air chamber is connected with the granulation zone, and the air outlet of the drying air chamber is connected with the fluidizing section, wherein the air outlet of the cooling air chamber is located at an end away from the magnesium chloride spray device, and the air outlet of the drying air chamber is located at an end close to the discharge port.

[0008] In the second aspect, a working method of a magnesium chloride granulation and drying integrated system is proposed, comprising:

[0009] Spraying magnesium chloride droplets into the granulation area of ​​the granulation and drying integrated machine through a magnesium chloride spraying device;

[0010] Inject cold air into the granulation zone through the cooling air chamber, and solidify the magnesium chloride droplets into magnesium chloride hexahydrate particles through the cold air;

[0011] Magnesium chloride hexahydrate particles enter the fluidizing section;

[0012] Injecting hot air into the fluidizing section through a drying air chamber, drying the magnesium chloride hexahydrate particles in the fluidizing section by the hot air to obtain dried magnesium chloride dihydrate particles;

[0013] The dried magnesium chloride dihydrate particles are discharged from the discharge port.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The present invention integrates the spray granulation of magnesium chloride brine and the drying process of magnesium chloride particles into one device. The device has a high degree of integration, reduces the number of devices, material transfer links and equipment failure points, reduces operating costs, and improves production efficiency.

[0016] 2. The spray granulation process disclosed in the present invention is mainly completed independently in the granulation area above the fluidizing section of the granulation and drying integrated machine, while the drying and dehydration process of the particles is mainly completed in the fluidizing section above the air distribution plate. The two processes are relatively independent, with less interference, easy to control and adjust, and greater independent operation flexibility.

[0017] 3. The present invention adopts a horizontal multi-chamber fluidized dynamic drying method. The hot air passes through the air distribution plate from bottom to top. The magnesium chloride particles undergo turbulent heat exchange with the hot air in the fluidized section on the air distribution plate. The drying intensity is high, the processing capacity is large, and the thermal efficiency is high.

[0018] 4. The present invention is provided with a plurality of air chambers, and an adjusting valve is provided on the air inlet pipe of each air chamber to adjust the air intake volume of each chamber. In addition, cold air granulation and hot air drying are completed in different areas, the processes are separated, the control is convenient, and the product quality is easy to ensure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0020] Figure 1 The granulation and drying process of magnesium chloride dihydrate disclosed in Example 1 of the present disclosure;

[0021] Figure 2 Schematic diagram of the spray granulation device disclosed in Example 1 of the present disclosure Figure 1 ;

[0022] Figure 3 Schematic diagram of the spray granulation device disclosed in Example 1 of the present disclosure Figure 2 ;

[0023] Figure 4 This is a schematic diagram of the installation position of the nozzle disclosed in Example 1 of the present disclosure;

[0024] Figure 5 This is the existing process flow chart of granulation and drying in a spray tower;

[0025] Figure 6 It is a process flow chart of spray granulation and drying in an existing granulation and drying integrated machine;

[0026] Figure 7 The present invention is a process flow chart for preparing anhydrous magnesium chloride by dehydrating bischofite.

[0027] Among them: 1. gas furnace, 2. hot air filter, 3. heat exchanger, 4. granulating and drying integrated machine, 5. air outlet, 6. partition, 7. air distribution plate, 8. air inlet, 9. discharge valve, 10. liquid spray device, 11. evaporation system, 12. vibrating screen, 13. dust removal system, 19. liquid inlet pipe, 20. liquid spray pipe A, 21. liquid spray pipe B, 22. nozzle, 23. integrated machine expansion section, 24. atomizer, 25. cyclone dust collector, 26. electrostatic precipitator, 27. induced draft fan, 28. atomizer, 29. fluidized bed, 30. electric heater. DETAILED DESCRIPTION

[0028] The present disclosure is further described below in conjunction with the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present disclosure, and do not specifically refer to any part or element in the present disclosure and should not be understood as limitations on the present disclosure.

[0032] In the present disclosure, terms such as "fixed connection", "connected", "connection", etc. should be understood in a broad sense, indicating that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant scientific research or technical personnel in this field, the specific meanings of the above terms in the present disclosure can be determined according to specific circumstances, and they cannot be understood as limitations on the present disclosure.

[0033] Example 1

[0034] In this embodiment, a magnesium chloride granulation and drying integrated system is disclosed, including a granulation and drying integrated machine and a magnesium chloride spray device, the granulation and drying integrated machine includes a connected granulation zone and a fluidizing section, the granulation zone is located above the fluidizing section, a discharge port is arranged at one end of the fluidizing section, the granulation zone is connected to the magnesium chloride spray device, the discharge port and the magnesium chloride spray device are located on the same side of the granulation and drying integrated machine, a cooling air chamber and a drying air chamber are arranged below the granulation and drying integrated machine, the cooling air chamber outlet is connected to the granulation zone, and the drying air chamber outlet is connected to the fluidizing section, wherein the cooling air chamber outlet is located at an end away from the magnesium chloride spray device, and the drying air chamber outlet is located at an end close to the discharge port.

[0035] Furthermore, the magnesium chloride spray device includes a liquid inlet pipe and a liquid spray pipe, the first end of the liquid inlet pipe extends into the granulation area of ​​the granulation and drying integrated machine and is connected to the first end of the liquid spray pipe, and the second end of the liquid spray pipe is provided with a nozzle.

[0036] Furthermore, a cooling air chamber air inlet is arranged on the cooling air chamber, and the cooling air chamber air inlet is connected to the cold air generating device; a drying air chamber air inlet is arranged on the drying air chamber, and the drying air chamber air inlet is connected to the hot air generating device.

[0037] Furthermore, the cold air generating device includes a cold air filter, the air inlet of the cold air filter is used to communicate with the cold air, and the air outlet of the cold air filter is connected to the air inlet of the cooling air chamber.

[0038] Furthermore, the hot air generating device includes a filter, a gas furnace and a heat exchanger, the air inlet of the filter is used to connect with the cold air, the air outlet of the filter is connected with the air inlet of the heat exchanger, the smoke outlet of the gas furnace is connected with the smoke inlet of the heat exchanger, and the air outlet of the heat exchanger is connected with the air inlet of the drying air chamber.

[0039] Furthermore, an air distribution plate is provided on the granulating and drying integrated machine, and the air outlet of the cooling air chamber and the air outlet of the drying air chamber are both located below the air distribution plate.

[0040] Furthermore, partition plates are provided on the upper part of the air distribution plate corresponding to each air chamber.

[0041] Furthermore, an air outlet is arranged on the granulation and drying integrated machine, and the air outlet is connected with the granulation area.

[0042] Furthermore, the air outlet is connected to the dust removal system.

[0043] A magnesium chloride granulation and drying integrated system disclosed in this embodiment is described in detail.

[0044] The molecular formula of magnesium chloride is: MgCl2·6H2O, molecular weight: 203.31, easily soluble in water and ethanol, sensory indicators: white flakes, bitter taste. Pure magnesium chloride is colorless monoclinic crystals, industrial products are usually yellow-brown, bitter and salty. It is easy to absorb moisture, and loses 2 molecules of crystal water when dissolved in water at 100°C. Its aqueous solution is neutral at room temperature. It begins to lose part of hydrogen chloride and decompose at 110°C, and turns into oxychloride when strongly heated. When heated rapidly, it decomposes at about 118°C. The melting point and boiling point of anhydrous magnesium chloride MgCl2 are 712°C and 1412°C respectively. The particles after liquid spray granulation are magnesium chloride hexahydrate, i.e., MgCl2·6H2O. Then, hot air drying is performed to remove crystal water. Crystal water begins to be removed after drying for a period of time at 118°C. As the temperature rises, the remaining crystal water is continuously removed. When drying for a period of time at 172-179°C, a total of 4 crystal waters are removed to obtain the final product, magnesium chloride dihydrate, i.e., MgCl2·2H2O.

[0045] Uses of magnesium chloride: It is an important inorganic raw material in the chemical industry, used to produce magnesium products such as magnesium carbonate, magnesium hydroxide, magnesium oxide, and is also used as a raw material for antifreeze. The main uses include: curing agent; nutritional enhancer; flavoring agent (used in combination with magnesium sulfate, salt, calcium hydrogen phosphate, calcium sulfate, etc.); fermentation aid for Japanese sake, etc.; dehydrating agent (used in fish cakes, dosage 0.05% to 0.1%); tissue improver (used in combination with polyphosphates as an elasticity enhancer for fish paste products). Due to its strong bitterness, the common dosage is less than 0.1%.

[0046] Wheat flour treating agent; dough quality improver; oxidant; fish canning improver; malt saccharification agent.

[0047] The existing processes for granulation and drying of magnesium chloride granules prepared from magnesium chloride solution (51% concentration brine) include the following three:

[0048] A. Existing process technology 1: CN109502614A A method and device for preparing anhydrous magnesium chloride by large-scale spray drying.

[0049] like Figure 5 As shown, it is a spray granulation drying process, 51% magnesium chloride brine is granulated by high-speed rotation of the atomizer 24 in the spray tower, and hot air is provided by the high-temperature flue gas furnace to enter the spray tower to dry the droplets of the magnesium chloride solution. The droplets formed by the high-speed rotation of the atomizer are dried into magnesium chloride particles, and then enter the cyclone dust collector 25 and the electrostatic precipitator 26 for particle collection through the suction of the induced draft fan 27. The collected particles enter the subsequent production process as finished products.

[0050] The process is characterized by a simple flow, with granulation and drying both carried out in a spray tower. However, since it takes a lot of heat and a long drying process to dry the 51% magnesium chloride hexahydrate brine into magnesium chloride dihydrate particles, the production capacity is very low because both granulation and drying are carried out in a spray tower.

[0051] B. Existing process technology 2: CN1108855 Method for producing magnesium chloride particles.

[0052] like Figure 6 As shown, spray granulation and drying are carried out in a fluidized bed. A 51% magnesium chloride brine enters the fluidized bed 29 through a pressure or compressed air atomizer 3. Hot air is heated to about 100-170°C by an electric heater 30 and enters the fluidized bed. The solution droplets and the hot air carry out convection heat and mass transfer in the fluidized bed to dry the droplets. The droplets cannot form particles directly, and it is necessary to spray a base material on the material layer of the fluidized bed 29. The small-diameter particle base material is spread in the fluidized bed 29 as a seed crystal. The seed crystals of the base material are continuously grown and dried by spraying, coating and drying of the droplets to form large-particle finished materials.

[0053] Since the base material needs to be laid on the fluidized bed and the base material crystal grows by coating the solution spray droplets, the system operation requires high accuracy and the control requirements for time and temperature are also very high, which makes the system operation complicated and prone to product failures. For example, the product particles are too small, the diameter of the spray droplets is too large, the base material particles are unevenly distributed, resulting in the product particle diameter distribution being too large, and other problems.

[0054] C. Existing process technology three: CN1944261 A method for preparing anhydrous magnesium chloride by dehydrating bischofite.

[0055] like Figure 7 As shown, a method for preparing anhydrous magnesium chloride by dehydrating bischofite is provided. First, aniline hydrochloride is reacted with bischofite to generate aniline hydrochloride-magnesium chloride hexahydrate double salt. Then, the magnesium chloride hexahydrate is granulated and dried by a spray method to form double salt particles suitable for fluidization. Finally, the crystal water and aniline hydrochloride are removed by a fluidized bed to obtain anhydrous magnesium chloride product.

[0056] Since granulation and drying are divided into two steps, the material transfer equipment between granulation and drying are all dynamic equipment, and the fans and filters in the exhaust gas treatment system are consumable parts, which are easy to damage and need frequent maintenance and replacement, resulting in reduced equipment start-up rate and affecting production capacity. Since the granulation and drying of this process are divided into two steps, the investment in equipment, plant and building foundation is increased accordingly.

[0057] In order to simplify the production process and improve the quality of magnesium chloride dihydrate products, this embodiment discloses an integrated system for granulating and drying magnesium chloride, such as Figure 1 As shown, it includes: a granulation and drying integrated machine 4, a magnesium chloride spraying device 10, a dust removal system 13 and an evaporation system 11.

[0058] Among them, a granulation zone and a fluidizing section are provided in the granulation and drying integrated machine 4, and the granulation zone is respectively connected with the cooling air chamber and the magnesium chloride spray device 10. The magnesium chloride solution is sprayed into the granulation zone through the magnesium chloride spray device 10 to form spray droplets, and cold air is added to the granulation zone through the cooling air chamber. During the movement and falling of the spray droplets in the air, they are gradually broken into smaller droplets by the friction resistance of the air. The smaller droplets are cooled and shrunk after contacting the cold air added in the granulation zone, and the granulation is completed to obtain magnesium chloride hexahydrate particles.

[0059] The granulation zone is located above the fluidizing section. After the magnesium chloride hexahydrate granulation is completed in the granulation zone, the formed magnesium chloride hexahydrate particles enter the fluidizing section. The fluidizing section is connected with the drying air chamber. Hot air is injected into the fluidizing section through the drying air chamber to dry the magnesium chloride hexahydrate particles to obtain dried magnesium chloride dihydrate particles. A discharge port is arranged on the fluidizing section, and the dried magnesium chloride dihydrate particles are discharged through the discharge port.

[0060] In order to ensure that the spray droplets in the granulation area can fully contact with the cold air to complete the granulation, the magnesium chloride spray device 10 and the discharge port are arranged at the same end of the granulation and drying integrated machine 4, the cooling air chamber is arranged at the end away from the discharge port, and the drying air chamber is arranged at the end close to the discharge port.

[0061] Specifically, the cooling air chamber is located at the droplet falling area of ​​the granulation zone.

[0062] The cooling air chamber is provided with a cooling air chamber outlet and a cooling air chamber inlet, the cooling air chamber outlet is connected to the granulation area, the cooling air chamber inlet is connected to a cold air generating device, the cold air generating device includes a cold air filter, the inlet of the cold air filter is used to communicate with cold air, and the outlet of the cold air filter is connected to the cooling air chamber inlet. The cold air generating device is used to inject cold air into the cooling air chamber, and then the cooling air chamber injects cold air into the granulation area for granulation.

[0063] The drying chamber is provided with a drying chamber outlet and a drying chamber inlet. The drying chamber outlet is connected to the fluidizing section, and the drying chamber inlet is connected to the hot air generating device. The hot air generating device includes a filter 2, a gas furnace 1 and a heat exchanger 3. The inlet of the filter 2 is used to communicate with the cold air, the outlet of the filter 2 is connected to the inlet of the heat exchanger 3, the flue gas outlet of the gas furnace 1 is connected to the flue gas inlet of the heat exchanger 3, and the outlet of the heat exchanger 3 is connected to the inlet of the drying chamber. The air is filtered through the filter 2, and the impurities are removed to become clean air and enter the heat exchanger 3. The flue gas generated by the combustion of the gas furnace 1 is mixed with the air to generate 300-400°C flue gas, which also enters the heat exchanger 3. The 300-400°C flue gas and the clean air are indirectly heat-exchanged in the heat exchanger 3, so that the clean air is heated to 110-180°C in the heat exchanger 3. The hot air of 110-180°C enters the fluidizing section to dry the magnesium chloride particles.

[0064] In specific implementation, the cold air is clean air at room temperature, with a temperature not exceeding 50°C.

[0065] The magnesium chloride spray device 10 includes a liquid inlet pipe 19, a liquid spray pipe and a nozzle 22. The first end of the liquid inlet pipe 19 extends into the granulation area of ​​the granulation and drying integrated machine and is connected to the first end of the liquid spray pipe. The nozzle 22 is set at the second end of the liquid spray pipe. The second end of the liquid inlet pipe 19 is connected to the evaporation system 11.

[0066] The evaporation system 11 is used to concentrate the magnesium chloride solution to a concentration of more than 50%. The magnesium chloride solution concentrated to a concentration of more than 50% enters the liquid spray pipe through the liquid inlet pipe and is finally sprayed into the granulation area by the nozzle 22.

[0067] The evaporation system 11 here adopts existing equipment and is existing technology, so the structure of the evaporation system 11 will not be described in detail.

[0068] In addition, the magnesium chloride solution with a concentration of more than 50% obtained by the evaporation system has a temperature of 120-210°C. When the magnesium chloride solution in this temperature space enters the granulation area, it can be granulated by cold air with a temperature not exceeding 50°C.

[0069] The liquid spray pipe is arranged at one end of the discharge port of the granulation drying integrated machine 4, so that the magnesium chloride solution with a concentration of more than 50% can be sprayed into the granulation area from one end of the discharge port of the granulation drying integrated machine 4 to the other end to form spray droplets, the spraying distance is ≥3m, and the residence time can be controlled at 0.5-5s. The magnesium chloride solution leaves the nozzle 22 and is gradually broken into smaller droplets by the friction resistance of the air during the air travel and falling process in the granulation area. The smaller droplets are cooled and shrunk after contacting the cold air in the granulation area to complete the granulation. The cold air in the granulation area is provided by a cooling air chamber arranged in the droplet falling area, away from the discharge port.

[0070] The nozzle can adopt a pressure type or a two-fluid structure. If it is a pressure spray, the granulation diameter can be controlled by adjusting the solution pressure. If it is a two-fluid spray (that is, high-pressure compressed air is sprayed out from the nozzle together with the solution), the granulation diameter can be controlled by adjusting the compressed air flow and pressure.

[0071] Spray granulation can adopt different spraying methods and spraying positions according to the production capacity and particle size requirements. The spraying pipe can be set as a single layer or multiple layers, each layer can be set as one, or set as two symmetrical ones, such as Figure 2 , 3 shown. Figure 2 The arrangement of the liquid spray pipes is as follows: the liquid spray pipes are arranged in multiple layers, and each layer has one liquid spray pipe A20. Figure 3 The arrangement of the middle liquid spraying pipe is as follows: the liquid spraying pipe is arranged in multiple layers, and each layer of liquid spraying pipes includes two symmetrical liquid spraying pipes B21.

[0072] The nozzle 22 is installed on the liquid spraying pipe. The nozzle 22 is horizontally arranged in the granulation area of ​​the granulation and drying machine 4, or is inclined upward, such as Figure 4 As shown, the nozzle 22 is tilted upward at an inclination angle α of 0-45°, wherein the inclination angle α is determined according to the length of the granulation zone of the granulation and drying integrated machine 4 .

[0073] In addition, a plurality of nozzles 22 may be arranged at intervals on each spray pipe, and the spraying range of the magnesium chloride spray device 10 in the granulation area may be controlled by the number of nozzles 22, the spacing between the plurality of nozzles 22, and the setting angle of the nozzles 22, wherein the nozzles 22 are detachably arranged relative to the spray pipe, thereby realizing the replacement of the nozzles 22.

[0074] In this embodiment, an air distribution plate 7 is arranged below the granulation and drying integrated machine 4, and the cooling air chamber and the drying air chamber are both located below the air distribution plate. The cold air discharged from the cooling air chamber enters the granulation area through the air distribution plate 7 to participate in granulation, and the hot air discharged from the drying air chamber enters the fluidizing section through the air distribution plate 7 and contacts with the magnesium chloride hexahydrate particles, thereby drying the magnesium chloride hexahydrate particles to obtain dried magnesium chloride dihydrate particles.

[0075] The wind speed of hot air injected into the fluidizing section by the drying air chamber is 0.8-2m / s. Adjusting valves are provided at the air inlet 8 of the cooling air chamber and the drying air chamber, and the air volume entering each air chamber is adjusted by adjusting the valves to obtain different wind speeds.

[0076] A partition plate 6 is arranged on the upper part of the air distribution plate 7 at the position corresponding to each wind chamber, and the fluidized section is divided into a plurality of drying chambers by the partition plate 6. The height of the partition plate 6 is adjustable. By adjusting the height of the partition plate 6, the drying residence time of the magnesium chloride particles in each drying chamber is controlled, and the free water and crystal water of the magnesium chloride particles are gradually removed, and the magnesium chloride hexahydrate particles are dried into magnesium chloride dihydrate particles.

[0077] A discharge valve 9 is installed at the discharge port, and the discharge port is connected to the vibrating screen. The magnesium chloride dihydrate particles obtained by drying in the fluidized section are discharged through the discharge valve 9 at the discharge port and enter the vibrating screen 12. After the magnesium chloride dihydrate particles are processed by the vibrating screen 12, the final magnesium chloride dihydrate particles are obtained.

[0078] An air outlet 5 is also provided on the granulation and drying machine, and the air outlet 5 is connected to the granulation area and the dust removal system respectively. The exhaust gas in the granulation and drying machine is discharged through the air outlet 5 and then enters the dust removal system. The dust removal system treats the exhaust gas and then discharges it after it meets the standards. Among them, an integrated machine expansion section 23 is provided on the part of the bed of the granulation and drying machine near the air outlet. The expansion section is the structure of the upper body of the drying machine, specifically, the volume of the part of the bed of the drying machine near the air outlet is expanded to reduce the wind speed, reduce the amount of dust carried away by the outlet wind, and reduce the amount of material entrained by the wind.

[0079] The present embodiment discloses an integrated magnesium chloride granulation and drying system, which takes a granulation and drying integrated machine as the core, realizes the granulation of magnesium chloride brine and the drying process of wet magnesium chloride particles in one device by adding a liquid spray granulation device, and prepares a magnesium chloride dihydrate particle product. The spray granulation of magnesium chloride brine and the drying process of magnesium chloride particles are integrated in one device, which simplifies the process flow, makes the process equipment more integrated, reduces the number of equipment and material transfer links, reduces equipment failure points, reduces maintenance costs, reduces floor space, reduces operating costs, and reduces investment.

[0080] In addition, the present embodiment discloses an integrated system for granulating and drying magnesium chloride, wherein a magnesium chloride spray device is arranged at a discharge end, and magnesium chloride droplets are sprayed into a granulation zone; an air outlet of a cooling air chamber is arranged at an end away from the spray device and at a droplet falling area, and cold air is injected into the granulation zone, so that magnesium chloride hexahydrate granulation can be completed in the granulation zone by using cold air; the magnesium chloride hexahydrate particles after granulation enter a fluidizing section; an air outlet of a drying air chamber is arranged at an end close to the discharge end, and hot air is injected into the fluidizing section to dry the magnesium chloride hexahydrate particles obtained in the granulation zone, so as to obtain dried magnesium chloride dihydrate particles; the granulation process and the drying process are respectively carried out in the granulation zone and the fluidizing section, and the two processes are relatively independent, with less interference, easy to control and adjust, and greater independent operation flexibility; the spray direction is inclined upward, and the droplets will stay in the air for a period of time, which is convenient for increasing the cold air contact time, and can extend the granulation time, ensure the granulation effect, and have a high balling rate.

[0081] This embodiment adopts a horizontal multi-chamber fluidized dynamic drying method. The hot air passes through the air distribution plate from bottom to top, and the material undergoes turbulent heat exchange with the hot air in the fluidized section on the air distribution plate. The drying intensity is high, the processing capacity is large, and the thermal efficiency is high.

[0082] In this embodiment, a plurality of air chambers are arranged, and each air chamber has an air inlet pipe, and an adjusting valve is arranged on the air inlet pipe to adjust the air inlet volume of each chamber, and cold air granulation and hot air drying are completed in different chambers, the processes are separated, the control is convenient, and the product quality is easy to ensure.

[0083] The present embodiment discloses an integrated system for granulating and drying magnesium chloride, which realizes the production of magnesium chloride dihydrate particles by first spraying to form droplets, then directly cooling and solidifying the droplets into particles with cold air, and finally drying the particles with hot air. The spray granulation and drying processes are integrated in one device. The spray granulation method is adopted, and the particle size can be controlled by adjusting the solution pressure or the compressed air pressure, etc. The control means are more flexible and the particle forming rate is higher.

[0084] Example 2

[0085] In this embodiment, a working method of a magnesium chloride granulation and drying integrated system is disclosed, comprising:

[0086] Spraying magnesium chloride droplets into the granulation area of ​​the granulation and drying integrated machine through a magnesium chloride spraying device;

[0087] Inject cold air into the granulation zone through the cooling air chamber, and solidify the magnesium chloride droplets into magnesium chloride hexahydrate particles through the cold air;

[0088] Magnesium chloride hexahydrate particles enter the fluidizing section;

[0089] Injecting hot air into the fluidizing section through a drying air chamber, drying the magnesium chloride hexahydrate particles in the fluidizing section by the hot air to obtain dried magnesium chloride dihydrate particles;

[0090] The dried magnesium chloride dihydrate particles are discharged from the discharge port.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A magnesium chloride granulation and drying integrated system, characterized in that: The invention comprises a granulation drying integrated machine and a magnesium chloride spray device, wherein the granulation drying integrated machine comprises a granulation zone and a fluidizing section which are connected to each other, the granulation zone is located above the fluidizing section, a discharge port is arranged at one end of the fluidizing section, the granulation zone is connected to the magnesium chloride spray device, the discharge port and the magnesium chloride spray device are located on the same side of the granulation drying integrated machine, a cooling air chamber and a drying air chamber are arranged below the granulation drying integrated machine, the air outlet of the cooling air chamber is connected to the granulation zone, and the air outlet of the drying air chamber is connected to the fluidizing section, wherein the air outlet of the cooling air chamber is located at an end away from the magnesium chloride spray device, and the air outlet of the drying air chamber is located at an end close to the discharge port; The magnesium chloride liquid spraying device comprises a liquid inlet pipe and a liquid spraying pipe, wherein the first end of the liquid inlet pipe extends into the granulation area of ​​the granulation and drying integrated machine and is connected with the first end of the liquid spraying pipe, and a nozzle is arranged at the second end of the liquid spraying pipe; The nozzle is horizontally arranged in the granulation area of ​​the granulation and drying machine, or is arranged to be inclined upward; the range of the inclination angle α of the nozzle being arranged to be inclined upward is 0°<α≤45°; the nozzle is detachably arranged relative to the liquid spraying pipe; The liquid spray pipe is arranged at one end of the discharge port of the granulating and drying integrated machine, so that the magnesium chloride solution with a concentration of more than 50% can be sprayed from one end of the discharge port of the granulating and drying integrated machine to the other end into the granulating area to form spray droplets, and the spraying distance is ≥3m.

2. A magnesium chloride granulation and drying integrated system as claimed in claim 1, characterized in that: The cooling air chamber is provided with a cooling air chamber air inlet, which is connected to the cold air generating device; the drying air chamber is provided with a drying air chamber air inlet, which is connected to the hot air generating device.

3. A magnesium chloride granulation and drying integrated system as claimed in claim 2, characterized in that: The cold air generating device comprises a cold air filter, an air inlet of the cold air filter is used to communicate with the cold air, and an air outlet of the cold air filter is communicated with the air inlet of the cooling air chamber.

4. A magnesium chloride granulation and drying integrated system as claimed in claim 2, characterized in that: The hot air generating device includes a filter, a gas furnace and a heat exchanger. The air inlet of the filter is used to communicate with the cold air, the air outlet of the filter is connected to the air inlet of the heat exchanger, the smoke outlet of the gas furnace is connected to the smoke inlet of the heat exchanger, and the air outlet of the heat exchanger is connected to the air inlet of the drying air chamber.

5. A magnesium chloride granulation and drying integrated system as claimed in claim 1, characterized in that: An air distribution plate is arranged on the granulating and drying integrated machine, and the air outlet of the cooling air chamber and the air outlet of the drying air chamber are both located below the air distribution plate.

6. A magnesium chloride granulation and drying integrated system as claimed in claim 1, characterized in that: The granulating and drying integrated machine is provided with an air outlet of the granulating and drying integrated machine, and the air outlet of the granulating and drying integrated machine is communicated with the granulating area.

7. A magnesium chloride granulation and drying integrated system as claimed in claim 6, characterized in that: The air outlet of the granulating and drying integrated machine is connected to the dust removal system.

8. A working method of a magnesium chloride granulation and drying integrated system, using the magnesium chloride granulation and drying integrated system according to any one of claims 1 to 7, characterized in that: include: Spraying magnesium chloride droplets into the granulation area of ​​the granulation and drying integrated machine through a magnesium chloride spraying device; Inject cold air into the granulation area through the cooling air chamber, and solidify the magnesium chloride droplets into magnesium chloride hexahydrate particles through the cold air; Magnesium chloride hexahydrate particles enter the fluidizing section; Injecting hot air into the fluidizing section through a drying air chamber, drying the magnesium chloride hexahydrate particles in the fluidizing section by the hot air to obtain dried magnesium chloride dihydrate particles; The dried magnesium chloride dihydrate particles are discharged from the discharge port.

Images