Ammonium chloride concentrating, drying and recycling system

Abstract

The utility model discloses an ammonium chloride concentrating, drying and recycling system which is characterized in that an ammonium chloride stock solution pipe is connected with a heater tube pass inlet through the cold side of a tail gas preheater, a heater tube pass outlet is connected with a feeding hole of a crystallizer, and a crystallization circulating liquid outlet is connected with an inlet of a material circulating pump; an outlet of the salt crystallization leg is connected with a thickening tank, a bottom outlet of the thickening tank is connected with a centrifugal machine, a centrifugal solid phase outlet is connected with a wet material inlet of a rotary dryer, and a dry material outlet of the rotary dryer is connected with an ammonium chloride dry material conveying pipe; performing reflux at a centrifugal liquid phase outlet; a top air outlet of the crystallizer is connected with an inlet of the steam compressor through the scrubber tower; an outlet of the steam compressor is connected with a shell pass inlet of the heater and a steam inlet of the rotary dryer; an exhaust port of the rotary dryer is connected with a cyclone bag-type dust collector through a dust induced draft fan, and a clean gas outlet is connected with the hot side of the tail gas preheater. The system can stably recover ammonium chloride products, and is good in quality, low in production energy consumption and good in environmental protection benefit.

Description

Technical Field

[0001] The utility model relates to an ammonium chloride drying system, in particular to an ammonium chloride concentration, drying and recovery system, and belongs to the technical field of comprehensive resource utilization. Background Art

[0002] Ammonium chloride is a common industrial product that plays an important role in metal welding, textile printing and dyeing, battery manufacturing, and agricultural production. In metal welding, ammonium chloride is used as a flux. The hydrogen chloride gas produced by the thermal decomposition of ammonium chloride can remove oxides from the metal surface, cleaning the metal surface and promoting better fusion of the metals during welding. Furthermore, in common zinc-manganese dry-cell batteries, ammonium chloride participates in the electrochemical processes within the battery, promoting ion conduction between the positive and negative electrodes, thereby ensuring normal discharge and providing power for various electronic devices. As a byproduct of chemical processing, ammonium chloride has the advantages of high nitrogen content and easy availability, providing essential elements for crop growth and increasing crop yields.

[0003] The rotary drum dryer is suitable for processing large quantities of granular materials with low moisture content. Its main body is a slightly inclined rotating cylinder. The wet material is fed from one end, passes through the interior of the cylinder, and is effectively dried by contact with the hot air passing through the cylinder or the heated wall surface, and finally discharged from the bottom of the other end.

[0004] Bag filters are the most commonly used dust removal equipment in the ammonium chloride production industry. When dust-laden gas passes through the filter bags, the dust is trapped on the outer surface of the bags, and the purified gas is discharged. Bag filters offer high dust removal efficiency, stable operation, and a wide range of applications. They are effective in collecting dry dust and dust from feeding and conveying during the ammonium chloride production process. They operate by relying on the filtering action of the filter bags. When dust accumulates to a certain level on the bag surface, a cleaning device removes the dust, restoring the bag's filtering function. Collected production dust needs to be centrally stored to prevent secondary dust dispersal. Storage equipment should be well sealed and moisture-resistant to prevent dust from agglomerating due to moisture.

[0005] Chinese utility model patent publication number CN 220926540U discloses a double-rotary drum dryer for sludge, comprising a mounting base, a fixed sleeve, a rotating sleeve, a rotary drive mechanism, and an oscillating scraper mechanism. Wet sludge is fed into the machine from the upper end of the rotating sleeve, and hot air from a hot air blower enters the lower end of the rotating sleeve, rotating the sleeve via a rotating mechanism. The hot air heats and dehumidifies the wet sludge, which then flows toward the lower side of the drum under the action of gravity, achieving drying and dehumidification. This technical solution has the following drawbacks: 1. The heated air is provided by the hot air blower, resulting in low drying efficiency, high power consumption, and poor economic efficiency; 2. The outlet material is not cooled by cold air, and the dehumidified, hot material can become damp again, affecting the drying effect; 3. The heated air enters the equipment from the bottom and is unevenly distributed, preventing timely contact with the heated medium, which affects the heating effect; 4. The lack of a weighing device makes it impossible to monitor the drying effect and material accumulation within the rotary dryer, which can easily cause blockage and system shutdown.

[0006] Chinese utility model patent publication number CN 211885853U discloses a bag-type dust collector for the processing and production of lanthanum, cerium, and rare earth. The bag-type dust collector comprises a main body, an electromagnetic pulse valve, dust bags, a dust discharge valve, and a dust cleaning bin. Dust-laden exhaust gas enters the device through the air inlet, passes through a second porous plate, a dust bag, and a first porous plate, and is subsequently discharged through the air outlet. The dust cleaning bin collects the falling solid dust, which is ultimately discharged through the dust discharge valve. This technical solution has the following defects: 1. The imported dust-laden gas is not blocked, and the high-speed exhaust gas directly flows through the bags, which will damage the bags and affect the long-term operation of the bag dust collector; 2. For sticky material dust, it is very easy to adhere to the absorption bag. The compressed air sprayed by the electromagnetic pulse valve cannot blow the dust off the bags, and the cleaning efficiency is poor; 3. The sticky dust will accumulate in the cleaning bin at the bottom of the dust collector, and it cannot be effectively cleaned during long-term operation, causing the dust collector to trip; 4. The dust collector is discharged directly in the open air at the bottom, and the secondary dust is large, which affects the surrounding environment and the health of the operators. Utility Model Content

[0007] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and utility model title of this application, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0008] In view of the above problems and / or the problems existing in the prior art, the present utility model is proposed.

[0009] The purpose of the utility model is to overcome the problems existing in the prior art and provide an ammonium chloride concentration, drying and recovery system, which can stably recover ammonium chloride products, and the mass fraction, water content and sulfate content of ammonium chloride all meet the requirements of "GB / T2946-2018 Ammonium Chloride", reaching the level of superior products, and has low production energy consumption and good environmental benefits.

[0010] To solve the above technical problems, the utility model provides an ammonium chloride concentration, drying and recovery system, comprising an ammonium chloride stock liquid pipe, the outlet of the ammonium chloride stock liquid pipe being connected to the cold side inlet of the tail gas preheater, the cold side outlet of the tail gas preheater being connected to the outlet pipe of a material circulation pump via an ammonium chloride preheating liquid pipe, the outlet pipe of the material circulation pump being connected to the tube side inlet of a heater, the tube side outlet of the heater being connected to the feed port of a crystallizer, and the circulating liquid outlet of the crystallizer being connected to the inlet of the material circulation pump via an evaporation circulation pipe;

[0011] The salt leg outlet of the crystallizer is connected to the inlet of the thickening tank through a slurry delivery pump, the bottom outlet of the thickening tank is connected to the inlet of the centrifuge, the solid phase outlet of the centrifuge is connected to the wet material inlet of the rotary dryer through a wet material delivery pipe, and the dry material outlet of the rotary dryer is connected to the ammonium chloride dry material delivery pipe; the liquid phase outlet of the centrifuge is connected to the inlet of the mother liquor tank, and the outlet of the mother liquor tank is connected to the inlet of the material circulation pump through a mother liquor reflux pump;

[0012] The top air outlet of the crystallizer is connected to the air inlet of the scrubber, the air outlet of the scrubber is connected to the inlet of the steam compressor, and the outlet of the steam compressor is connected to the shell side inlet of the heater and the steam inlet of the rotary dryer through a pressurized steam pipe;

[0013] The exhaust port of the rotary dryer is connected to the inlet of the dust induced draft fan, the outlet of the dust induced draft fan is connected to the dust tangential inlet of the cyclone bag dust collector, the clean gas outlet of the cyclone bag dust collector is connected to the hot side inlet of the exhaust gas preheater, and the hot side outlet of the exhaust gas preheater is connected to the atmosphere.

[0014] As an improvement of the present invention, the inlet of the air blower is communicated with the atmosphere, and the outlet of the air blower is connected to the cold air inlet of the rotary dryer through an air conveying pipe.

[0015] As a further improvement of the present invention, the ammonium chloride dry material conveying pipe is connected to the feeding port of the ammonium chloride product conveying vehicle.

[0016] As a further improvement of the present invention, the discharge port of the cyclone bag dust collector is connected to the inlet of the dust collecting hopper through a recovered dry material conveying pipe, the outlet of the dust collecting hopper is connected to the inlet of the conveying auger, and the outlet of the conveying auger is connected to the feeding port of the ammonium chloride product conveying vehicle.

[0017] As a further improvement of the present invention, the cylinder body of the rotary dryer comprises a feed sealing cover, a hot side rotary drum, a dust outlet sealing cover, a cold side rotary drum and a dry material outlet sealing cover in sequence, and the feed sealing cover, the dust outlet sealing cover and the dry material outlet sealing cover are all fixed on the mounting base; the upper part of the feed sealing cover is connected with a wet material inlet, the feed end of the hot side rotary drum and the outlet of the feed sealing cover are movably connected and sealed to each other, the discharge end of the hot side rotary drum and the feed end of the dust outlet sealing cover are movably connected and sealed to each other, the top of the dust outlet sealing cover is provided with a dust outlet, the discharge end of the dust outlet sealing cover is movably connected and sealed to the feed end of the cold side rotary drum, the discharge end of the cold side rotary drum and the feed end of the dry material outlet sealing cover are movably connected and sealed to each other, and the bottom of the dry material outlet sealing cover is connected with a dry material outlet; the inner walls of the hot side rotary drum and the cold side rotary drum are evenly provided with a plurality of copying plates;

[0018] A central air pipe is provided along the center line of the cylinder, and the central air pipe includes a hot side steam inlet, a hot side air pipe, a cold side air pipe and a cooling air inlet which are connected as one. The hot side steam inlet extends from the center of the feed end wall panel of the feed sealing cover, the hot side air pipe is located in the inner cavity of the hot side rotary drum, the cold side air pipe is located in the inner cavity of the dry material outlet sealing cover, and the cooling air inlet extends from the center of the discharge end wall panel of the dry material outlet sealing cover. The connection between the hot side air pipe and the cold side air pipe is separated by a hot and cold gas barrier plate. A plurality of groups of conical nozzles pointing to the inner cavity of the cylinder are evenly provided along the axial and circumferential directions of the hot side air pipe and the cold side air pipe.

[0019] As a further improvement of the present invention, the bottom of the mounting base is connected to the weighing base below via twelve spring support rods.

[0020] As a further improvement of the present invention, the hot side steam inlet is connected to the pressurized steam pipe.

[0021] As a further improvement of the present invention, the inner cavity of the main cylinder body of the cyclone bag dust collector is provided with a dust cyclone, and the upper outer wall of the main cylinder body is connected with a dust tangential inlet and communicates with the annular cyclone space on the periphery of the dust cyclone, the upper end of the annular cyclone space is closed, and the lower ends of the annular cyclone space and the dust cyclone are open. A plurality of dust bags are installed in the inner cavity of the dust cyclone, and the upper ends of each dust bag are respectively connected to the bag flower plate, and a vibration plate parallel to the bag flower plate is provided above the bag flower plate, and the lower end of the vibration plate is connected to the bag flower plate through a plurality of vibration plate support columns; a vibration motor is fixed on the vibration plate.

[0022] Compared to existing technologies, the present invention achieves the following beneficial effects: 1. This system, used for product drying and dust treatment in the ammonium chloride production industry, achieves a dust absorption rate exceeding 99% for ammonium chloride dust and allows for secondary recovery of collected ammonium chloride dust solids. This effectively conserves ammonium chloride product resources during production and meets increasingly stringent environmental emission requirements. The ammonium chloride mass fraction, water content, and sulfate content of the resulting ammonium chloride product after crystallization, drying, and dust treatment all meet the requirements of GB / T 2946-2018 Ammonium Chloride, reaching premium quality.

[0023] 2. The rotary dryer is connected to the ground foundation via twelve spring support rods, which effectively absorb the severe vibrations during operation and reduce the impact of equipment vibration on the foundation. The spring support rods also increase the vibration frequency of the dryer body, accelerating the shedding of sticky materials inside the dryer, reducing scaling, and extending the continuous operation time of the rotary dryer.

[0024] 3. A weighing base is designed at the bottom of the dryer to monitor the ammonium chloride processing capacity inside the dryer in real time, preventing the amount of ammonium chloride entering the dryer from exceeding the equipment's processing capacity. The total weight of the entire cylindrical dryer is monitored in real time through a pressure sensor, and an overweight alarm is designed to avoid the risk of overflow and shutdown of the drying system.

[0025] 4. The secondary steam produced is recycled through the compressor. The secondary steam at the top of the crystallizer is pressurized and heated by the compressor to provide heat for the heater and dryer, effectively reducing the power consumption of the traditional dryer hot air blower, reducing the operating cost of the device, and reducing the energy consumption per unit of ammonium chloride production.

[0026] 5. The dryer is designed with a rotating hot and cold coexisting gas pipeline. The dryer's heating steam and cooling air are discharged through a tapered nozzle on the outer wall of the central gas pipeline, directly contacting the ammonium chloride medium. This ensures efficient contact between the hot and cold gases and the treated material and minimizes heat loss. A gas baffle separates the hot and cold media in the pipeline. When high-pressure secondary steam and cooling air are discharged through the tapered nozzle, they disperse ammonium chloride dust, effectively increasing the heat exchange area between the treated medium and the gas. Furthermore, to prevent ammonium chloride from accumulating on the outer wall of the pipeline and impacting gas discharge and system operation, the dryer is designed with a central gas pipeline rotating motor and spiral scrapers. The rotation of the pipeline and scrapers shovels any ammonium chloride adhering to the outer wall of the pipeline to the bottom of the dryer. Cooling air is also introduced at the end of the pipeline to cool the dried ammonium chloride solids and prevent moisture from returning after the high-temperature ammonium chloride is discharged.

[0027] 6. A tail gas waste heat recovery device was designed. The tail gas preheater was designed to recover the residual heat in the exhaust gas to preheat the ammonium chloride feed, increase the initial temperature of ammonium chloride entering the crystallization system, effectively reduce the energy consumption of the device operation, improve the system economy, and also reduce the risk of high-temperature tail gas scalding operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. The drawings are only provided for reference and explanation, and are not intended to limit the present invention. Among them:

[0029] Figure 1 This is a flow chart of the ammonium chloride concentration, drying and recovery system of the utility model;

[0030] Figure 2 It is a three-dimensional diagram of the rotary dryer in the utility model;

[0031] Figure 3 This is a cross-sectional view of the rotary dryer in the present utility model;

[0032] Figure 4 This is a cross-sectional view of the cyclone bag dust collector of the present invention;

[0033] Figure 5 This is a three-dimensional cross-sectional view of the cyclone bag dust collector of the utility model;

[0034] Figure 6 This is a detailed view of the clean air chamber in the cyclone bag dust collector;

[0035] Figure 7 This is a top view of the clean air chamber of the cyclone bag dust collector;

[0036] Figure 8 This is a three-dimensional diagram of a cyclone bag dust collector.

[0037] In the figure: 1. Crystallizer; 2. Heater; 3. Scrubber; 4. Steam Compressor; 5. Thickening Tank; 6. Centrifuge; 7. Mother Liquor Tank; 8. Rotary Dryer; 9. Cyclone Bag Dust Collector; 10. Dust Hopper; 11. Conveyor Auger; 12. Ammonium Chloride Product Conveyor Vehicle; 13. Exhaust Gas Preheater;

[0038] Rotary dryer: 8a1. Head end base; 8a2. Center air pipe rotating motor; 8a3. Hot side steam inlet; 8a4. Transmission mechanism shield; 8a5. Wet material inlet;

[0039] 8b1. Feed seal cover; 8b2. Scraper plate; 8b3. Hot side drum; 8b4. Hot side drum drive gear; 8b5. Hot side air pipe; 8b6. Spiral scraper; 8b7. Conical nozzle;

[0040] 8c1. Dust outlet sealing cover; 8c2. Dust outlet; 8c3. Cold-side drum drive gear; 8c4. Dry material outlet sealing cover; 8c5. Cooling air inlet; 8c6. Dry material outlet; 8c7. Hot and cold gas barrier; 8c8. Cold-side air pipe; 8c9. Cold-side drum;

[0041] 8d1. Cold-side rotating motor; 8d2. Mounting base; 8d3. Hot-side rotating motor; 8d4. Weighing base; 8d5. Spring support rod; 8e. Lifting adjustment mechanism;

[0042] Cyclone bag dust collector: 9a. Clean air outlet; 9b. Dust swirl channel; 9c. Ear seat; 9d. Connecting flange; 9e. Ash bin; 9f. Star-shaped dust exhaust valve; 9g. Dust swirl cylinder; 9h. Dust bag; 9j. Dust collector inner wall; 9k. Clean air chamber; 9m. Vibrating motor; 9n. Eccentric impeller; 9p. Spring support leg; 9q. Bag flower plate; 9r. Vibrating plate support column; 9s. Vibrating plate; 9t. Dust tangential inlet.

[0043] B1. Material circulation pump; B2. Slurry delivery pump; B3. Mother liquor reflux pump; B4. Dust induced draft fan; B5. Air supply fan;

[0044] G0. Ammonium chloride raw liquid pipe; G1. Ammonium chloride preheating liquid pipe; G2. Evaporation circulation pipe; G3. Slurry conveying pipe; G4. Mother liquor conveying pipe; G5. Wet material conveying pipe; G6. Mother liquor reflux pipe; G7. Dust conveying pipe; G8. Clean gas outlet pipe; G9. Recovered dry material conveying pipe; G10. Ammonium chloride dry material conveying pipe; G11. Secondary steam conveying pipe; G12. Pressurized steam pipe; G13. Air conveying pipe. DETAILED DESCRIPTION

[0045] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the embodiments described are only a part of the present invention, not all of the embodiments.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0047] like Figure 1As shown, the ammonium chloride concentration, drying and recovery system of the present invention includes a crystallizer 1, a heater 2, a scrubber 3, a steam compressor 4, a thickening tank 5, a centrifuge 6, a mother liquor tank 7, a rotary dryer 8, a cyclone bag dust collector 9, a dust collecting hopper 10, a conveying auger 11, an ammonium chloride product conveying vehicle 12 and an exhaust gas preheater 13.

[0048] The ammonium chloride preheating liquid pipe G1 is connected to the outlet pipe of the material circulation pump B1, which is connected to the tube-side inlet of heater 2. The tube-side outlet of heater 2 is connected to the feed port of crystallizer 1. The circulating liquid outlet of crystallizer 1 is connected to the inlet of material circulation pump B1 via evaporation circulation pipe G2. The salt leg outlet of crystallizer 1 is connected to the inlet of slurry delivery pump B2, which is connected to the inlet of thickening tank 5 via slurry delivery pipe G3. The bottom outlet of thickening tank 5 is connected to the inlet of centrifuge 6. The solid phase outlet of centrifuge 6 is connected to the wet material inlet of rotary dryer 8 via wet material delivery pipe G5. The dry material outlet of rotary dryer 8 is connected to the feed port of ammonium chloride product delivery vehicle 12 via ammonium chloride dry material delivery pipe G10.

[0049] The liquid phase outlet of the centrifuge 6 is connected to the inlet of the mother liquid tank 7 through the mother liquid delivery pipe G4, the outlet of the mother liquid tank 7 is connected to the inlet of the mother liquid reflux pump B3 through the mother liquid reflux pipe G6, and the outlet of the mother liquid reflux pump B3 is connected to the inlet circulation pipe of the material circulation pump B1.

[0050] The top air outlet of the crystallizer 1 is connected to the air inlet of the scrubbing tower 3 through the secondary steam delivery pipe G11, the air outlet of the scrubbing tower 3 is connected to the inlet of the steam compressor 4, and the outlet of the steam compressor 4 is connected to the shell side inlet of the heater 2 and the steam inlet of the rotary dryer 8 through the pressurized steam pipe G12.

[0051] The inlet of the air blower B5 is connected to the atmosphere, and the outlet of the air blower B5 is connected to the cold air inlet of the rotary dryer 8 through the air conveying pipe G13. The exhaust port of the rotary dryer 8 is connected to the inlet of the dust induced draft fan B4, and the outlet of the dust induced draft fan B4 is connected to the dust tangential inlet 9t of the cyclone bag dust collector 9 through the dust conveying pipe G7. The clean air outlet 9a of the cyclone bag dust collector 9 is connected to the hot side inlet of the exhaust gas preheater 13 through the clean air outlet pipe G8, and the hot side outlet of the exhaust gas preheater 13 is connected to the atmosphere; the outlet of the ammonium chloride raw liquid pipe G0 is connected to the cold side inlet of the exhaust gas preheater 13, and the cold side outlet of the exhaust gas preheater 13 is connected to the inlet of the ammonium chloride preheating liquid pipe G1.

[0052] The discharge port of the cyclone bag dust collector 9 is connected to the inlet of the dust collecting hopper 10 through the recovered dry material conveying pipe G9. The outlet of the dust collecting hopper 10 is connected to the inlet of the conveying auger 11. The outlet of the conveying auger 11 is also connected to the feeding port of the ammonium chloride product conveying vehicle 12.

[0053] The low-concentration ammonium chloride solution enters the cold side of the tail gas preheater 13 through the ammonium chloride raw liquid pipe G0. After being preheated by the clean gas on the hot side, it enters the circulation system of the crystallizer 1 through the ammonium chloride preheating liquid pipe G1, first flows through the tube side of the heater 2 for heating, and then enters the crystallizer 1 for evaporation and crystallization. When the solid-liquid ratio of ammonium chloride in the salt leg at the bottom of the crystallizer 1 reaches 20%, the bottom slurry is discharged through the slurry delivery pipe G3 and sent to the thickening tank 5 by the slurry delivery pump B2 for solid precipitation. The ammonium chloride slurry with a high solid content at the bottom of the thickening tank 5 enters the centrifuge 6 directly below for solid-liquid separation. After solid-liquid separation in the centrifuge 6, the wet ammonium chloride solid is sent to the rotary dryer 8 through the wet material delivery pipe G5 for discharge drying. The dried ammonium chloride solid is transported to the ammonium chloride product delivery vehicle 12 through the ammonium chloride dry material delivery pipe G10 and is transported and sold after measurement.

[0054] The liquid ammonium chloride mother liquor after centrifugation in centrifuge 6 is transferred to mother liquor tank 7 for storage via mother liquor transfer pipe G4. It is then returned to evaporation circulation pipe G2 by mother liquor return pump B3 via mother liquor reflux pipe G6. The ammonium chloride material within crystallizer 1 is circulated through evaporation circulation pipe G2 and material circulation pump B1, where it is heated by heater 2 and then returned to crystallizer 1 for recirculation.

[0055] The secondary steam generated by the evaporation of the material is discharged from the top of the crystallizer 1 and sent to the scrubber 3 through the secondary steam delivery pipe G11 for cleaning and dust removal. It then enters the steam compressor 4 for compression and pressure increase. The pressurized compressed steam is delivered to the shell side of the heater 2 and the hot side steam inlet of the rotary dryer 8 through the pressurized steam pipe G12 to provide the heat source required for heat exchange.

[0056] The air blower B5 absorbs clean air and passes it into the cooling air inlet of the rotary dryer 8 through the air delivery pipe G13, providing refrigerant for drying ammonium chloride at the cooling outlet.

[0057] Gas containing ammonium chloride dust is discharged from the top outlet of rotary dryer 8 and discharged by dust induced draft fan B4 into cyclone bag filter 9, where it absorbs ammonium chloride dust. The gas containing ammonium chloride dust then enters the cyclone bag filter tangentially through the dust tangential inlet pipe. After rotating through the dust swirl channel for one or several cycles, it enters the dust chamber where it is adsorbed and filtered by the dust bag. The swirl of dust-laden gas effectively settles large ammonium chloride dust particles larger than 1 micron and droplets, reducing the risk of bag sticking. At the same time, the dust is decelerated in the dust swirl channel, effectively mitigating the impact of the high-speed dust-laden gas on the bag, thereby extending the service life of the dust bag in the dust chamber.

[0058] The dust is then discharged pollution-free through the clean gas outlet pipe G8, ensuring that the filtered exhaust meets environmental protection requirements. The exhaust gas flows through the clean gas outlet pipe G8 and passes through the hot side of the exhaust preheater 13 to preheat the low-concentration ammonium chloride material, thereby recovering the residual heat in the exhaust gas, improving the economic efficiency of the system operation and reducing the risk of burns to operators caused by high-temperature exhaust gas.

[0059] The ammonium chloride dust accumulated at the bottom of the cyclone bag dust collector 9 is sent to the dust hopper 10 for temporary storage through the dry material recovery conveying pipe G9, and then transported to the ammonium chloride product conveying vehicle 12 through the conveying auger 11.

[0060] like Figure 2 、 Figure 3 As shown, the cylinder body of the rotary dryer 8 includes a feed sealing cover 8b1, a hot side drum 8b3, a dust outlet sealing cover 8c1, a cold side drum 8c9 and a dry material outlet sealing cover 8c4 in sequence. The feed sealing cover 8b1, the dust outlet sealing cover 8c1 and the dry material outlet sealing cover 8c4 are all fixed on the mounting base 8d2. The upper portion of the feed side wall panel of the feed sealing cover 8b1 is connected to a wet material inlet 8a5, the feed end of the hot side drum 8b3 is movably connected to the outlet of the feed sealing cover 8b1 and are sealed to each other, the discharge end of the hot side drum 8b3 is movably connected to the feed end of the dust outlet sealing cover 8c1 and are sealed to each other, a dust outlet 8c2 is provided at the top of the dust outlet sealing cover 8c1, the discharge end of the dust outlet sealing cover 8c1 is movably connected to the feed end of the cold side drum 8c9 and are sealed to each other, the discharge end of the cold side drum 8c9 is movably connected to the feed end of the dry material outlet sealing cover 8c4 and are sealed to each other, and the bottom of the dry material outlet sealing cover 8c4 is connected to a dry material outlet 8c6.

[0061] A central air pipe is provided along the centerline of the cylinder, which includes a hot side steam inlet 8a3, a hot side air pipe 8b5, a cold side air pipe 8c8 and a cooling air inlet 8c5, which are connected in sequence. The hot side steam inlet 8a3 extends from the center of the feed end wall panel of the feed sealing cover 8b1, the hot side air pipe 8b5 is located in the inner cavity of the hot side rotating cylinder 8b3, the cold side air pipe 8c8 is located in the inner cavity of the dry material outlet sealing cover 8c4, and the cooling air inlet 8c5 extends from the center of the discharge end wall panel of the dry material outlet sealing cover 8c4. The connection between the hot side air pipe 8b5 and the cold side air pipe 8c8 is separated by a hot and cold gas barrier plate 8c7.

[0062] The outer circumference of the hot side gas pipe 8b5 and the cold side gas pipe 8c8 is wrapped with a spiral scraper 8b6, and multiple groups of conical nozzles 8b7 pointing to the inner cavity of the cylinder are evenly arranged along the axial and circumferential directions of the hot side gas pipe 8b5 and the cold side gas pipe 8c8.

[0063] A plurality of lifting plates 8b2 are evenly arranged on the inner walls of the hot side drum 8b3 and the cold side drum 8c9. A hot side drum transmission gear 8b4 is provided on the central outer periphery of the hot side drum 8b3. A hot side rotating motor 8d3 is installed in the middle of the mounting base 8d2. The pinion at the output end of the hot side rotating motor 8d3 meshes with the hot side drum transmission gear 8b4.

[0064] A cold side drum transmission gear 8c3 is provided on the central periphery of the cold side drum 8c9, a cold side rotating motor 8d1 is installed on the mounting base 8d2, and the pinion at the output end of the cold side rotating motor 8d1 is meshed with the cold side drum transmission gear 8c3.

[0065] The head end of the mounting base 8d2 is installed with a head end base 8a1, and the head end base 8a1 is installed with a central air pipe rotating motor 8a2. The central air pipe rotating motor 8a2 drives the air pipe and the spiral scraper 8b6 to rotate at a constant speed through a belt, pushing the material to the end, and at the same time moving in the opposite direction of the scraper 8b2, which is conducive to breaking up large pieces of material; a transmission mechanism shield 8a4 is installed on the outside of the belt.

[0066] Wet ammonium chloride enters the dryer's feed seal 8b1 through wet material inlet 8a5. Due to its inclination angle, the wet ammonium chloride flows into the inner cavity of the hot-side rotating drum 8b3. As the drum rotates at a constant speed, a lifter 8b2 attached to the inner wall of the drum lifts the wet material, allowing it to fully contact the hot steam and evaporate the moisture from its surface. When the dry ammonium chloride solid reaches the rear end of the drum, cooling air ejected from the air pipe cools the solid ammonium chloride and enters the dry material outlet seal 8c4 before being discharged through the dry material outlet 8c6 at the bottom of the dryer.

[0067] The hot side drum 8b3 is located between the feed sealing cover 8b1 and the dust outlet sealing cover 8c1. The small gear at the rotor shaft end of the hot side rotating motor 8d3 drives the hot side drum transmission gear 8b4 to rotate, and the rotation rate of the hot side drum 8b3 can be controlled by adjusting the motor frequency.

[0068] Similarly, the cold-side drum 8c9 is located between the dust outlet sealing cover 8c1 and the dry material outlet sealing cover 8c4. A pinion on the rotor shaft of the cold-side rotary motor 8d1 drives the cold-side drum transmission gear 8c3. The rotation rate of the cold-side drum 8c9 is controlled by adjusting the frequency of the cold-side rotary motor 8d1. While the three sealing covers remain stationary, the drum rotates, and its speed can be adjusted freely based on the amount of ammonium chloride processed.

[0069] The compressed steam pressurized by the steam compressor 4 enters the hot side gas pipe 8b5 through the hot side steam inlet 8a3 and flows out from the conical nozzles 8b7 evenly distributed on the outer wall of the gas pipe, providing heat for evaporating the surface moisture of ammonium chloride.

[0070] The cooling air introduced by the air blower B5 enters the cold side air supply pipe 8c8 through the cooling air inlet 8c5, and also flows out from the conical nozzles 8b7 evenly distributed on the outer wall of the pipe, cooling the dried ammonium chloride solid to facilitate loading and discharge.

[0071] The dryer's lower portion is designed with a monolithic mounting base 8d2, the bottom of which is connected to the lowest weighing base 8d4 via twelve spring support rods 8d5. These spring support rods 8d5 effectively absorb the intense vibrations of the dryer during operation, reducing their impact on the unit's foundation. They also enhance the dryer's vibration frequency, accelerating the shedding of adhering materials inside the dryer, reducing scaling, and extending the rotary dryer's continuous operation. A pressure sensor mounted on the weighing base 8d4 monitors the dryer's overall weight in real time, providing accurate information on the amount of ammonium chloride being processed, thereby enhancing operational accuracy.

[0072] A lifting adjustment mechanism 8e is designed between the mounting base 8d2 and the weighing base 8d4 to adjust the lifting height of one side of the dryer, thereby adjusting the inclination angle of the dryer drum and controlling the drying residence time of ammonium chloride.

[0073] like Figures 4 to 8 As shown, ammonium chloride dust enters the inner cavity of the cyclone bag filter 9 tangentially from the dust tangential inlet 9t. After rotating through the dust swirl channel 9b for one or several cycles, it enters the dust chamber and is adsorbed and filtered by the dust bag 9h. The swirl of dust-laden gas effectively settles large dust particles larger than 1 micron and droplets, reducing the risk of bag sticking. Simultaneously, the ammonium chloride dust is decelerated in the swirl channel, effectively mitigating the impact of the high-speed dust-laden gas on the dust bag 9h and extending the service life of the bag in the dust chamber.

[0074] Due to the special physical and chemical properties of ammonium chloride, it is very easy for ammonium chloride to fuse into droplets to form ammonium chloride solution that adheres to the bag. Traditional compressed air blowing and dust removal is ineffective and it is difficult to blow off the dust stuck to the bag. This solution has designed a vibrating device. The bag panel 9q on which the dust removal bag 9h is installed is installed on the structure above the dust chamber through spring legs 9p. Above the bag panel 9q, another layer of vibrating plate 9s is installed through vibrating plate support columns 9r. A vibration device is arranged in the center of the vibrating plate 9s, which consists of an eccentric impeller 9n driven by a vibrating motor 9m. The vibration amplitude and period of the dust collector are adjusted by adjusting the power of the vibrating motor 9m. By designing a vibrating dust removal device, the ammonium chloride dust adhering to the dust removal bag 9h is shaken off in a timely manner, effectively avoiding the dust sticking to the bag and extending the continuous working time of the ammonium chloride drying and dust removal device.

[0075] After prolonged dust removal, adherent liquid dust can adhere to the ash bin 9e and the inner wall 9j of the dust collector, significantly reducing the dust collector's efficiency and increasing the operating load on the dust collection system's fan. In this system, the ash bin 9e is connected to the main dust collector unit above via a connecting flange 9d, which is mounted to the unit's foundation via lugs 9c. During operation, the ash bin 9e can be quickly and easily disassembled for maintenance, and the inner wall 9j of the dust collector can also be regularly flushed, saving maintenance time and costs.

[0076] The bottom discharge port of the ash silo 9e is equipped with a star-shaped valve for dust removal. Compared to traditional flap dust discharge valves, the star-shaped valve is more efficient and better suited for sticky, liquid-containing dust. The speed of the star-shaped valve 9f is set to 10-15 rpm, which can be adjusted according to the dust accumulation level in the ash silo 9e. To ensure a good seal, the outer edge of the star-shaped valve 9f's blades is inlaid with rubber strips to strengthen the seal between the impeller and the pump casing. The rubber strips are made of wear-resistant and heat-resistant rubber, effectively preventing dust backflow from the bottom auger conveyor.

[0077] To maintain the long-term, efficient use of the dust collector bags (9h) and ensure corrosion resistance and high temperature resistance, the bags are made from a combination of natural fiber and polytetrafluoroethylene. A metal keel is built into the dust collector bags, effectively extending their shape and maintaining a dust removal rate of over 2 m / s. The dust collector bags (9h) are connected to the holes in the bag panel (9q) with a snap-on connection, facilitating bag maintenance and replacement, significantly improving re-installation efficiency.

[0078] Dust from the lower ash bin 9e of the cyclone bag filter 9 is discharged downward through the star-shaped dust discharge valve 9f and collected and buffered by the dust hopper 10. The ammonium chloride dust stored in the dust hopper 10 is fed by a disc feeder to the feed port of the conveying auger 11. The ammonium chloride dust is then delivered to the ammonium chloride product transport vehicle 12 via the conveying auger 7, where it is transported to downstream users along with the ammonium chloride solids after treatment in the dryer. The installation of the dust hopper 10 increases the operational flexibility of the dust collector's dust discharge and extends the operating time of the cyclone bag filter 9.

[0079] The above description is only a preferred embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention, but does not limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. In addition to the above embodiments, the present invention may have other implementation methods without departing from the spirit and scope of the present invention. The present invention may also have various changes and improvements, and all technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents. Technical features not described in the present invention can be achieved by or using existing technologies, and will not be described here.

Claims

1. An ammonium chloride concentration, drying and recovery system, comprising an ammonium chloride stock liquid pipe, characterized in that: The outlet of the ammonium chloride raw liquid pipe is connected to the cold side inlet of the tail gas preheater, the cold side outlet of the tail gas preheater is connected to the outlet pipe of the material circulation pump through the ammonium chloride preheating liquid pipe, the outlet pipe of the material circulation pump is connected to the tube side inlet of the heater, the tube side outlet of the heater is connected to the feed port of the crystallizer, and the circulating liquid outlet of the crystallizer is connected to the inlet of the material circulation pump through the evaporation circulation pipe; The salt leg outlet of the crystallizer is connected to the inlet of the thickening tank through a slurry delivery pump, the bottom outlet of the thickening tank is connected to the inlet of the centrifuge, the solid phase outlet of the centrifuge is connected to the wet material inlet of the rotary dryer through a wet material delivery pipe, and the dry material outlet of the rotary dryer is connected to the ammonium chloride dry material delivery pipe; the liquid phase outlet of the centrifuge is connected to the inlet of the mother liquor tank, and the outlet of the mother liquor tank is connected to the inlet of the material circulation pump through a mother liquor reflux pump; The top air outlet of the crystallizer is connected to the air inlet of the scrubber, the air outlet of the scrubber is connected to the inlet of the steam compressor, and the outlet of the steam compressor is connected to the shell side inlet of the heater and the steam inlet of the rotary dryer through a pressurized steam pipe; The exhaust port of the rotary dryer is connected to the inlet of the dust induced draft fan, the outlet of the dust induced draft fan is connected to the dust tangential inlet of the cyclone bag dust collector, the clean gas outlet of the cyclone bag dust collector is connected to the hot side inlet of the exhaust gas preheater, and the hot side outlet of the exhaust gas preheater is connected to the atmosphere.

2. The ammonium chloride concentration, drying and recovery system according to claim 1, wherein: The inlet of the air blower is communicated with the atmosphere, and the outlet of the air blower is connected to the cold air inlet of the rotary dryer through an air delivery pipe.

3. The ammonium chloride concentration, drying and recovery system according to claim 1, wherein: The ammonium chloride dry material conveying pipe is connected to the feeding port of the ammonium chloride product conveying vehicle.

4. The ammonium chloride concentration, drying and recovery system according to claim 3, wherein: The discharge port of the cyclone bag dust collector is connected to the inlet of the dust collecting hopper through a recovered dry material conveying pipe, the outlet of the dust collecting hopper is connected to the inlet of the conveying auger, and the outlet of the conveying auger is connected to the feeding port of the ammonium chloride product conveying vehicle.

5. The ammonium chloride concentration, drying and recovery system according to any one of claims 1 to 4, characterized in that: The cylinder of the rotary dryer includes a feed sealing cover, a hot side rotary drum, a dust outlet sealing cover, a cold side rotary drum and a dry material outlet sealing cover in sequence, and the feed sealing cover, the dust outlet sealing cover and the dry material outlet sealing cover are all fixed on the mounting base; the upper part of the feed sealing cover is connected with a wet material inlet, the feed end of the hot side rotary drum and the outlet of the feed sealing cover are movably connected and sealed to each other, the discharge end of the hot side rotary drum and the feed end of the dust outlet sealing cover are movably connected and sealed to each other, the top of the dust outlet sealing cover is provided with a dust outlet, the discharge end of the dust outlet sealing cover is movably connected and sealed to the feed end of the cold side rotary drum, the discharge end of the cold side rotary drum and the feed end of the dry material outlet sealing cover are movably connected and sealed to each other, and the bottom of the dry material outlet sealing cover is connected with a dry material outlet; the inner walls of the hot side rotary drum and the cold side rotary drum are evenly provided with a plurality of copying plates; A central air pipe is provided along the center line of the cylinder, which includes a hot side steam inlet, a hot side air pipe, a cold side air pipe and a cooling air inlet, which are connected in sequence. The hot side steam inlet extends from the center of the feed end wall plate of the feed sealing cover. The hot side air pipe is located in the inner cavity of the hot side drum. The cold side air pipe is located in the inner cavity of the dry material outlet sealing cover. The cooling air inlet extends from the center of the discharge end wall plate of the dry material outlet sealing cover. The connection between the hot side air pipe and the cold side air pipe is separated by a hot and cold gas barrier plate. A plurality of groups of conical nozzles pointing to the inner cavity of the cylinder are evenly arranged along the axial direction and circumferential direction of the hot side gas transmission pipe and the cold side gas transmission pipe.

6. The ammonium chloride concentration, drying and recovery system according to claim 5, characterized in that: The bottom of the mounting base is connected to the weighing base below through twelve spring support rods.

7. The ammonium chloride concentration, drying and recovery system according to claim 5, characterized in that: The hot side steam inlet is connected to the pressurized steam pipe.

8. The ammonium chloride concentration, drying and recovery system according to any one of claims 1 to 4, characterized in that: The inner cavity of the main cylinder of the cyclone bag dust collector is provided with a dust cyclone, and the upper outer wall of the main cylinder is connected with a dust tangential inlet and communicates with the annular cyclone space on the periphery of the dust cyclone, the upper end of the annular cyclone space is closed, and the lower ends of the annular cyclone space and the dust cyclone are open. A plurality of dust collection bags are installed in the inner cavity of the dust cyclone, and the upper ends of the dust collection bags are respectively connected to the bag flower plates, and a vibration plate parallel to the bag flower plates is provided above the bag flower plates, and the lower end of the vibration plate is connected to the bag flower plates through a plurality of vibration plate support columns; a vibration motor is fixed on the vibration plate.

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