Lithium bromide integrated refrigeration cooling device and method based on multi-heat source utilization

Abstract

The application discloses a lithium bromide integrated refrigeration cooling device based on multi-heat source utilization, which comprises a hot lye washing tower, a furnace gas washing tower, a hot water bucket, a hot water heater and a lithium bromide unit, the gas inlet of the hot lye washing tower is externally connected with the furnace gas outlet of a calcining furnace, the liquid inlet of the hot lye washing tower is externally connected with a hot lye bucket, the gas outlet of the hot lye washing tower is in communication with the gas inlet of the furnace gas washing tower, the furnace gas outlet of the furnace gas washing tower is externally connected with a condensation tower, the liquid inlet of the furnace gas washing tower is in communication with the hot water outlet of the lithium bromide unit, the liquid outlet of the furnace gas washing tower is in communication with the inlet of the hot water bucket, the outlet of the hot water bucket is in communication with the inlet of the hot water heater through a hot water pump, the outlet of the hot water heater is in communication with the heating inlet of the lithium bromide unit, and the cold water outlet of the lithium bromide unit is externally connected with a chilled water output pipeline. The application realizes energy saving and consumption reduction and improves product quality by comprehensively utilizing multi-heat sources and optimizing a refrigeration process to efficiently prepare 5-20 DEG C low-temperature chilled water and apply the chilled water to a soda production system.

Description

Technical Field

[0001] This invention relates to the field of refrigeration and cooling technology in chemical production, and in particular to an integrated lithium bromide refrigeration and cooling device and method based on the utilization of multiple heat sources. Background Technology

[0002] In the soda ash production process using the combined alkali process, multiple production stages require cooling to meet process requirements. However, traditional cooling methods mostly employ mechanical refrigeration, which suffers from high energy consumption and high operating costs. Furthermore, the soda ash production process generates a significant amount of waste heat, such as the heat from furnace gas in the calcination system, the heat from steam condensate in the calcination and dry ammonium systems, and the heat from low-pressure steam. If this waste heat cannot be effectively recovered and utilized, it not only wastes energy but also increases the company's production costs.

[0003] Lithium bromide refrigeration technology offers advantages such as energy saving and environmental friendliness, utilizing thermal energy to drive refrigeration and effectively reducing dependence on electricity. However, existing lithium bromide refrigeration units have some shortcomings in the application of the combined alkali process for soda ash production. These include a single heat source that cannot fully integrate various waste heat resources from the production process; an insufficiently optimized device structure leading to low heat transfer efficiency; and a lack of flexibility in the refrigeration method, making it difficult to adjust the use of heat sources and the refrigeration process according to different production conditions.

[0004] Therefore, developing a lithium bromide integrated refrigeration and cooling system and method that can fully utilize various waste heat resources in the soda ash production process, has a reasonable structure, and good refrigeration effect is of great practical significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a lithium bromide integrated refrigeration and cooling device based on the utilization of multiple heat sources. This device can efficiently produce low-temperature chilled water at 5-20℃ through the comprehensive utilization of multiple heat sources and the optimization of the refrigeration process, and can be widely used in multiple systems of soda ash production, thereby achieving energy saving, consumption reduction and product quality improvement.

[0006] Another technical problem to be solved by the present invention is to provide a method for the above-mentioned lithium bromide integrated refrigeration and cooling device based on the utilization of multiple heat sources.

[0007] The technical problem to be solved by this invention is achieved through the following technical solution. This invention is an integrated lithium bromide refrigeration and cooling device based on multi-heat source utilization. The device includes a hot alkaline scrubbing tower, a furnace gas scrubbing tower, a hot water tank, a hot water heater, and a lithium bromide unit. The gas inlet of the hot alkaline scrubbing tower is connected to the furnace gas outlet of the calcining furnace; the liquid inlet of the hot alkaline scrubbing tower is connected to a hot alkaline tank; the liquid outlet of the hot alkaline scrubbing tower is connected to a hot alkaline tank; the gas outlet of the hot alkaline scrubbing tower is connected to the gas inlet of the furnace gas scrubbing tower; the furnace gas outlet of the furnace gas scrubbing tower is connected to a condenser tower; the liquid inlet of the furnace gas scrubbing tower is connected to the hot water outlet of the lithium bromide unit; the liquid outlet of the furnace gas scrubbing tower is connected to the inlet of the hot water tank; the outlet of the hot water tank is connected to the inlet of the hot water heater via a hot water pump; the outlet of the hot water heater is connected to the heating inlet of the lithium bromide unit; and the cold water outlet of the lithium bromide unit is connected to a chilled water output pipeline.

[0008] The technical problem to be solved by the present invention can also be further achieved by the following technical solution: For the lithium bromide integrated refrigeration and cooling device based on the utilization of multiple heat sources described above, the lithium bromide unit includes a generator, an absorber, a condenser and an evaporator. The outlet of the hot water heater is connected to the heating inlet of the generator, the cooling outlet of the generator is connected to the inlet of the furnace gas scrubbing tower, a heat exchanger for exchanging lithium bromide solution and heat is connected between the generator and the absorber, the steam outlet of the generator is connected to the condenser, the cooling outlet of the condenser is connected to the refrigerant water inlet of the evaporator, the steam outlet of the evaporator is connected to the absorber, and a cooling water pipe is connected between the refrigerant water outlet of the evaporator and the refrigerant water inlet of the evaporator to facilitate heat exchange of the evaporator tube side to produce chilled water. A refrigerant pump is installed on the cooling water pipe. A concentrated lithium bromide solution pump is connected between the generator and the heat exchanger, and a dilute lithium bromide solution pump is connected between the absorber and the heat exchanger.

[0009] The technical problem to be solved by the present invention can also be further achieved by the following technical solution: For the lithium bromide integrated refrigeration and cooling device based on the utilization of multiple heat sources described above, the hot water tank is connected to a boiler soft water supply pipeline, and a water supply pipeline and a water return pipeline are connected between the hot water tank and the hot water heater.

[0010] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: For the lithium bromide integrated refrigeration and cooling device based on the utilization of multiple heat sources described above, the hot water heater is a tubular heat exchanger. The tube side of the tubular heat exchanger is connected between the hot water tank and the lithium bromide unit. The shell side inlet of the tubular heat exchanger is connected to the low-pressure steam network or the steam condensate pipeline for calcination, dry ammonium, heavy ash, and salt production. The shell side outlet of the tubular heat exchanger is connected to the steam condensate return network or the return water pipeline for calcination, dry ammonium, heavy ash, and salt production.

[0011] The technical problem to be solved by the present invention can also be further achieved by the following technical solution: For the lithium bromide integrated refrigeration and cooling device based on the utilization of multiple heat sources described above, there are two hot alkaline scrubbing towers and two furnace gas scrubbing towers. The gas outlets of the two hot alkaline scrubbing towers are respectively connected to the gas inlets of the two furnace gas scrubbing towers.

[0012] The technical problem to be solved by the present invention can also be further achieved through the following technical solution: For the lithium bromide integrated refrigeration and cooling device based on multiple heat sources described above, a lithium bromide integrated refrigeration and cooling method based on multiple heat sources is provided, wherein the heat source required by the lithium bromide unit is at least one of the following heat sources: Heat source 1: Recover the heat from the furnace gas in the calcination system and convert it into hot water as a heat source for the lithium bromide unit; Heat source 2: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems as the heat source for the lithium bromide unit; Heat source 3: Using steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems to indirectly heat hot water as a heat source for the lithium bromide unit; Heat source four: Using low-pressure steam to indirectly heat hot water as a heat source for lithium bromide units.

[0013] The technical problem to be solved by this invention can also be further achieved through the following technical solution: Regarding the lithium bromide integrated refrigeration and cooling method based on multi-heat source utilization described above, the heat source flow of the lithium bromide chiller unit includes: Route 1: Add a furnace gas scrubbing tower before the calcining furnace gas enters the condenser. The furnace gas, after being scrubbed by hot alkaline solution, enters the furnace gas scrubbing tower. Soft water is sprayed into the furnace gas scrubbing tower to scrub the furnace gas, recovering its heat and raising the hot water temperature to above 85°C. The furnace gas exiting the furnace gas scrubbing tower then goes to the condenser. The hot water exiting the furnace gas scrubbing tower returns to the hot water tank through a U-shaped water seal and is then pumped to the lithium bromide unit for use. The 75°C low-temperature hot water exiting the lithium bromide unit returns to the furnace gas scrubbing tower for circulation. The hot water tank is equipped with a high-level overflow port, and excess hot water returns to the condenser. In addition, a hot water heater is installed before the hot water pump outlet enters the lithium bromide unit, and low-pressure steam is connected to heat the hot water in the hot water tank. Once the hot water temperature reaches the standard, it is sent to the lithium bromide unit for use. After the system is operating normally, the steam is stopped. Route 2: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems at temperatures above 100℃ as the heat source for the lithium bromide unit, and then use the low-temperature condensate from the lithium bromide unit for subsequent processes. Route 3: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems at temperatures above 100℃ to indirectly heat hot water via a hot water heater, which is then used as a heat source for the lithium bromide unit. The low-temperature hot water exiting the lithium bromide unit is then recirculated for further heating. Route 4: Utilize low-pressure steam to indirectly heat hot water through a hot water heater, which is then used as a heat source for the lithium bromide chiller. The low-temperature hot water exiting the lithium bromide chiller is then recirculated for further heating.

[0014] The technical problem to be solved by the present invention can also be further achieved by the following technical solution: For the lithium bromide integrated refrigeration and cooling method based on the utilization of multiple heat sources described above, in this method, the lithium bromide unit includes a generator, an absorber, a condenser, an evaporator and a plate heat exchanger, and is further configured with a concentrated solution pump, a dilute solution pump and a refrigerant pump to transport and circulate the lithium bromide solution and refrigerant water in each container, and is also configured with a vacuum pump to periodically evacuate the unit. Its working process is as follows: high-temperature hot water from the calciner gas scrubbing tower at 85°C or above is pumped to the generator to heat the dilute lithium bromide solution into a concentrated solution, while generating refrigerant vapor. The low-temperature water exiting the generator is returned to the calciner gas scrubbing tower for hot water recycling. Other heat sources adopt the same process for entering and exiting the lithium bromide unit. A heat exchanger is installed during the process of lithium bromide concentrated solution flowing from the generator back to the absorber and lithium bromide dilute solution being transported from the absorber to the generator, so that the two can exchange heat. The concentrated solution is pumped by the concentrated solution pump to the heat exchanger to exchange heat with the dilute solution. After the heat exchange, it is sent to the absorber to absorb the refrigerant vapor from the evaporator to become a dilute solution. The heat released by the absorption is carried out by the cooling water. The dilute solution is then pumped by the dilute solution pump to the heat exchanger to exchange heat with the concentrated solution before going to the generator. The solution completes the entire cycle. The refrigerant vapor generated by the generator goes to the condenser, where it is cooled by cooling water to become liquid water, i.e., low-temperature refrigerant water. Then it flows back to the low-temperature refrigerant water evaporator E, so that the refrigerant water in the evaporator is continuously replenished. The low-temperature refrigerant water in the evaporator is circulated by the refrigerant pump and exchanges heat with the chilled water in the evaporator tube side to produce low-temperature chilled water of 5-20°C. The refrigerant vapor generated by the evaporator goes to the absorber and is absorbed by the dilute solution. At this point, the refrigerant water completes the entire cycle. The cooling water used by the absorber and condenser enters the circulating water cooling tower from the unit, is cooled down, and then is pumped back to the unit for use by the cooling water pump, and so on.

[0015] The technical problem to be solved by this invention can also be further achieved through the following technical solutions: Regarding the lithium bromide integrated refrigeration and cooling method based on multiple heat sources described above, in this method, the low-temperature chilled water produced by the lithium bromide unit is low-temperature chilled water of 5–20°C, including but not limited to the following system cooling: (1) Prepare low-temperature cold water at around 5-20℃ and send it to the external cooler of the crystallization system to reduce the temperature of the cold precipitation AI; (2) Prepare low-temperature cold water at around 5-20℃ and send it to the crystallization system pre-cooling external cooler to reduce the pre-cooling temperature of the crystallization AI. (3) Prepare low-temperature cold water at around 5-20℃ and send it to the external cooler of the crystallization system to reduce the temperature of the salt-out mother II; (4) Prepare low-temperature cold water at around 5-20℃ and send it to the carbonization tower of the carbonization system to reduce the carbonization extraction temperature; (5) Prepare low-temperature cold water at around 5-20℃ and send it to the mother liquor cooler of the carbonization system to reduce the temperature of the mother liquor entering the carbonization tower.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention can recover the heat of the furnace gas in the calcination system and utilize multiple heat sources such as steam condensate (directly or indirectly) from the calcination, dry ammonium, heavy ash, and salt production systems, as well as low-pressure steam, as heat sources for the lithium bromide unit. It fully integrates various waste heat resources in the soda ash production process of the combined alkali process, improves the comprehensive utilization rate of energy, and reduces energy consumption and production costs. 2. This invention is equipped with a hot alkaline washing tower and a furnace gas washing tower, which can perform multi-stage washing of calcining furnace gas. This not only effectively recovers the heat of the furnace gas, but also removes impurities from the furnace gas, thereby improving the product quality in subsequent production processes. 3. This invention provides various heat source processes for lithium bromide refrigeration units, including recovering furnace gas heat, directly utilizing steam condensate, indirectly utilizing steam condensate to heat hot water, and utilizing low-pressure steam to heat hot water. The appropriate heat source process can be flexibly selected according to the supply of different heat sources and actual needs in the production process to ensure the stable operation of the refrigeration system. 4. The 5-20℃ low-temperature chilled water produced by the lithium bromide unit of the present invention can be used for cooling multiple systems in the soda ash production process, such as the external cooler for cold precipitation, the external cooler for pre-cooling precipitation, and the external cooler for salt precipitation in the crystallization system, as well as the carbonation tower and the mother liquor cooler in the carbonation system. By providing low-temperature chilled water to these key parts, the temperature in the production process is effectively reduced, product quality and production efficiency are improved, and the company's market competitiveness is further enhanced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one structure of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Reference Figure 1A lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization, comprising a hot alkaline scrubbing tower 2, a furnace gas scrubbing tower 1, a hot water tank 3, a hot water heater 5, and a lithium bromide unit, specifically: Hot alkali scrubbing tower 2 and furnace gas scrubbing tower 1 play important roles in gas treatment and heat recovery within the unit. The gas inlet of hot alkali scrubbing tower 2 is connected to the furnace gas outlet of the calcining furnace, and the liquid inlet of hot alkali scrubbing tower 2 is connected to a hot alkali tank. The liquid outlet of hot alkali scrubbing tower 2 is also connected to a hot alkali tank. The gas outlet of hot alkali scrubbing tower 2 is connected to the gas inlet of furnace gas scrubbing tower 1. The furnace gas outlet of furnace gas scrubbing tower 1 is connected to a condenser. The liquid inlet of furnace gas scrubbing tower 1 is connected to the hot water outlet of the lithium bromide unit. The liquid outlet of furnace gas scrubbing tower 1 is connected to the inlet of hot water tank 3. The outlet of hot water tank 3 is connected to the inlet of hot water heater 5 via a hot water pump. The outlet of hot water heater 5 is connected to the heating inlet of the lithium bromide unit. The cold water outlet of the lithium bromide unit is connected to a cold water tank. The chilled water output pipe leads to the hot water outlet of the lithium bromide unit in the furnace gas scrubbing tower 1. When the furnace gas generated by the calcining furnace enters the hot alkaline scrubbing tower 2, it comes into full contact with the alkaline solution flowing from the hot alkaline solution tank. The alkaline solution can absorb some impurities and harmful substances in the furnace gas, thus purifying it. At the same time, the hot alkaline solution also absorbs heat from the furnace gas during the scrubbing process, raising its own temperature. The scrubbed furnace gas is discharged from the gas outlet of the hot alkaline scrubbing tower 2 and enters the furnace gas scrubbing tower 1. Inside the furnace gas scrubbing tower 1, soft water from the return water pipe sprays the furnace gas again, further purifying it and fully recovering the residual heat. The soft water absorbs heat, raises its temperature, and forms hot water, which flows out from the liquid outlet of the furnace gas scrubbing tower 1 and enters the hot water tank 3.

[0020] Preferably, there are two hot alkaline scrubbing towers 2 and two furnace gas scrubbing towers 1. The gas outlets of the two hot alkaline scrubbing towers 2 are connected to the gas inlets of the two furnace gas scrubbing towers 1, respectively, so that the furnace gas can be more fully scrubbed and heat recovered, thereby improving the efficiency and stability of the entire device.

[0021] The hot water tank 3 is a key component in the device for hot water storage and initial supply. On one hand, it receives hot water from the gas scrubbing tower 1 and stores it to provide a heat source for the subsequent refrigeration process. On the other hand, the hot water tank 3 is connected to the boiler soft water supply pipeline, which can replenish the water lost due to evaporation, leakage, etc., and ensure the water balance in the system. The hot water tank 3 is connected to the boiler soft water supply pipeline, and there are supply and return water pipelines between the hot water tank 3 and the hot water heater 5. Both the supply and return water pipelines are equipped with hot water pumps 4.

[0022] The hot water heater 5 plays an important role in the device for secondary heating of hot water. Preferably, the hot water heater 5 is a tubular heat exchanger 8. The tube side of the tubular heat exchanger 8 is connected between the hot water tank 3 and the lithium bromide unit. The shell side inlet of the tubular heat exchanger 8 is connected to the low-pressure steam network or the steam condensate pipeline for calcination, dry ammonium, heavy ash, and salt production. The shell side outlet of the tubular heat exchanger 8 is connected to the steam condensate return network or the return water pipeline for calcination, dry ammonium, heavy ash, and salt production. When the low-pressure steam or high-temperature steam condensate enters the shell side, it exchanges heat with the hot water in the tube side, transferring heat to the hot water and further increasing the temperature of the hot water to meet the temperature requirements of the lithium bromide unit.

[0023] The lithium bromide unit is the core component of the entire refrigeration and cooling system. The unit includes a generator 6, an absorber 10, a condenser 7, and an evaporator 9. Hot water from the outlet of the hot water heater 5 enters the heating inlet of the generator 6. Inside the generator 6, the hot water heats the dilute lithium bromide solution. As the temperature rises, the water in the dilute lithium bromide solution continuously evaporates, forming refrigerant vapor, while the lithium bromide solution gradually concentrates into a concentrated solution. The cooling outlet of the generator 6 is connected to the inlet of the furnace gas scrubbing tower 1. The low-temperature water exiting the generator 6 returns to the furnace gas scrubbing tower 1 for hot water recycling, achieving heat recovery and reuse. The concentrated solution generated by generator 6 is transported to heat exchanger 8 by lithium bromide concentrated solution pump. After exchanging heat with the dilute solution from absorber 10, it enters absorber 10. In absorber 10, the concentrated solution absorbs refrigerant vapor from evaporator 9 and becomes dilute solution again, while releasing the heat of absorption. Absorber 10 is connected to a cooling water pipe, and the cooling water carries away the heat of absorption to ensure the normal operation of the absorption process. The refrigerant vapor generated by generator 6 enters condenser 7. Inside condenser 7, the refrigerant vapor exchanges heat with cooling water, its temperature decreases, and it condenses into liquid water, i.e. low-temperature refrigerant water. The cooling outlet of condenser 7 is connected to the refrigerant water inlet of evaporator 9. The low-temperature refrigerant water flows into evaporator 9 to provide a cold source for the refrigeration process. After the low-temperature refrigerant water enters the evaporator 9, it evaporates and absorbs heat inside the evaporator 9, which lowers the temperature of the chilled water in the tube side of the evaporator 9, producing low-temperature chilled water of 5-20℃. The refrigerant vapor generated by the evaporator 9 enters the absorber 10 and is absorbed by the dilute solution, completing the circulation of the refrigerant water. A cooling water pipe connects the refrigerant water outlet and the refrigerant water inlet of the evaporator 9. A refrigerant pump is installed on the cooling water pipe, which circulates and transports the low-temperature refrigerant water, enhancing the heat exchange effect inside the evaporator 9 and improving the refrigeration efficiency.

[0024] In addition, a lithium bromide concentrated solution pump is connected between the generator 6 and the heat exchanger 8, and a lithium bromide dilute solution pump is connected between the absorber 10 and the heat exchanger 8. These pumps are responsible for transporting the concentrated and dilute solutions to the heat exchanger 8 for heat exchange, thereby achieving solution recycling. At the same time, the lithium bromide unit is also equipped with a vacuum pump, which periodically extracts air and non-condensable gases from the unit to maintain a high vacuum level and ensure the normal operation of the lithium bromide refrigeration process.

[0025] A lithium bromide integrated refrigeration and cooling method based on multi-heat source utilization provides the required heat to the lithium bromide unit by flexibly using multiple heat sources, achieving efficient and energy-saving refrigeration and cooling effects. Specifically: In this method, the heat source required for the lithium bromide unit is at least one of the following heat sources: Heat source 1: Recover the heat from the furnace gas in the calcination system and convert it into hot water as a heat source for the lithium bromide unit; A furnace gas scrubbing tower 1 is added before the calcining furnace gas enters the condenser. The furnace gas, after being scrubbed by the hot alkaline scrubbing tower 2, enters the furnace gas scrubbing tower 1. Inside the furnace gas scrubbing tower 1, the furnace gas is sprayed and scrubbed with soft water. The soft water absorbs the heat in the furnace gas, raising its temperature to above 85°C. The hot water from the furnace gas scrubbing tower 1 returns to the hot water tank 3 through a U-shaped water seal and is then pumped by the hot water pump 4 to the lithium bromide unit for use. The 75°C low-temperature hot water exiting the lithium bromide unit returns to the furnace gas scrubbing tower 1 for circulation, forming a hot water recycling system. The hot water tank 3 is equipped with a high-level overflow port, and excess hot water returns to the condenser. In addition, a hot water heater 5 is installed before the hot water pump 4 enters the lithium bromide unit and is connected to low-pressure steam to heat the hot water in the hot water tank 3. In the initial stage of system production and operation, the hot water is heated to the standard temperature using low-pressure steam and then sent to the lithium bromide unit for use. After the system is operating normally, the steam is stopped, and the waste heat of the furnace gas is fully utilized to meet the cooling demand.

[0026] Heat source 2: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems as the heat source for the lithium bromide unit; The calcination, dry ammonium, heavy ash, and salt production systems generate a large amount of steam condensate at temperatures above 100°C during production. This steam condensate contains abundant heat. This high-temperature steam condensate is directly introduced into the lithium bromide unit as a heat source. After releasing heat in the lithium bromide unit, the steam condensate cools down and becomes low-temperature condensate. It is then used in subsequent processes after exiting the lithium bromide unit, thus realizing the direct utilization of heat and the rational recovery of condensate.

[0027] Heat source 3: Using steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems to indirectly heat hot water as a heat source for the lithium bromide unit; Similarly, the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems, which operate at temperatures above 100°C, is used. However, an indirect heating method is employed, introducing the steam condensate into the hot water heater 5. The hot water heater 5 then transfers heat to the hot water, raising its temperature. This heated hot water is then used as the heat source for the lithium bromide unit. The low-temperature hot water exiting the lithium bromide unit is recycled back to the hot water heater 5 and reheated by the steam condensate, forming a hot water circulation heating system that improves energy efficiency.

[0028] Heat source four: Using low-pressure steam to indirectly heat hot water as a heat source for the lithium bromide unit; When other heat sources cannot meet the demand or serve as supplementary heat sources, low-pressure steam can be used to indirectly heat the hot water. Low-pressure steam is introduced into the shell side of the hot water heater 5 to exchange heat with the hot water in the tube side, raising the temperature of the hot water to the temperature required by the lithium bromide unit. The low-temperature hot water leaving the lithium bromide unit is then recycled back to the hot water heater 5 and continues to be heated by low-pressure steam, thus achieving a continuous supply of heat and recycling of hot water.

[0029] In this method, the lithium bromide unit includes a generator 6, an absorber 10, a condenser 7, an evaporator 9, and a plate heat exchanger 8. It is also equipped with a concentrated solution pump, a dilute solution pump, and a refrigerant pump to transport and circulate the lithium bromide solution and refrigerant water in each container. A vacuum pump is also configured to periodically evacuate the unit. Its workflow is as follows: 1. Heat source enters generator 6: High-temperature hot water above 85°C from calcining furnace gas scrubbing tower 1 is sent to generator 6 by hot water pump 4. Inside generator 6, the hot water heats the dilute lithium bromide solution, causing the water in the dilute solution to evaporate and become a concentrated solution, while generating refrigerant vapor. The low-temperature water exiting generator 6 is returned to calcining furnace gas scrubbing tower 1 for hot water recycling. Other heat sources adopt the same process for entering and exiting the lithium bromide unit.

[0030] 2. Solution heat exchange: A heat exchanger 8 is installed during the process of the concentrated lithium bromide solution flowing from the generator 6 back to the absorber 10 and the dilute lithium bromide solution being transported from the absorber 10 to the generator 6. The concentrated solution is pumped into the heat exchanger 8 by a concentrated solution pump to exchange heat with the dilute solution. The temperature of the concentrated solution decreases, and after heat exchange, it is sent to the absorber 10. The dilute solution absorbs heat from the concentrated solution and its temperature rises. It is then pumped back to the heat exchanger 8 to exchange heat with the concentrated solution again, and then goes to the generator 6. At this point, the solution completes the entire cycle.

[0031] 3. Refrigerant vapor treatment: The refrigerant vapor generated by generator 6 enters condenser 7, where it is cooled by cooling water to turn the refrigerant vapor into liquid water, i.e., low-temperature refrigerant water. The low-temperature refrigerant water then flows back to evaporator 9, so that the refrigerant water in evaporator 9 is continuously replenished.

[0032] 4. Refrigeration process: The low-temperature refrigerant water in the evaporator 9 is circulated by the refrigerant pump to exchange heat with the chilled water in the tube side of the evaporator 9, absorbing the heat of the chilled water and lowering the temperature of the chilled water to produce low-temperature chilled water of 5-20℃; the refrigerant vapor generated by the evaporator 9 enters the absorber 10 and is absorbed by the dilute solution, thus completing the entire circulation of the refrigerant water.

[0033] 5. Cooling water circulation: The cooling water used by the absorber 10 and condenser 7 enters the circulating water cooling tower from the unit. In the cooling tower, the temperature is reduced through heat exchange with the air. Then, the cooling water is pumped back to the unit for use. This cycle is repeated to ensure the normal heat dissipation of the absorber 10 and condenser 7.

[0034] In this method, the low-temperature chilled water produced by the lithium bromide unit is chilled water at a temperature of 5–20°C, including but not limited to the following systems for cooling: 1. Crystallization system cold condenser: Low-temperature chilled water at around 5-20℃ (preferably around 5.5℃) is produced and sent to the crystallization system cold condenser to lower the temperature of the cold condensation AI. During the crystallization process, a suitable low-temperature environment helps to improve crystallization efficiency and product quality. By using low-temperature chilled water to cool the cold condensation AI, the crystallization temperature can be precisely controlled, promoting uniform crystal growth and improving product purity and yield.

[0035] 2. Pre-cooling external cooler of crystallization system: Low-temperature cold water at around 5-20℃ is produced and sent to the pre-cooling external cooler of crystallization system to reduce the pre-cooling precipitation temperature. Pre-cooling precipitation is an important step in the crystallization process. By reducing the pre-cooling precipitation temperature, more favorable conditions can be created for the subsequent crystallization process, thereby improving the stability and efficiency of the entire crystallization system.

[0036] 3. Crystallization System Salting-out External Cooler: Low-temperature chilled water at around 5-20℃ (preferably around 5.5℃) is produced and sent to the crystallization system salting-out external cooler to lower the temperature of salting-out mother II. During the salting-out process, temperature control has a significant impact on the salting-out effect and product quality. The use of low-temperature chilled water can effectively lower the temperature of salting-out mother II, promote salt precipitation, and improve the purity and yield of the salt.

[0037] 4. Carbonization System Carbonization Tower: Low-temperature chilled water at around 5-20℃ is produced and sent to the carbonization system carbonization tower to lower the carbonization extraction temperature. In the carbonization reaction, the reaction temperature plays a key role in the reaction rate and product quality. By using low-temperature chilled water to cool the carbonization tower, the carbonization reaction temperature can be precisely controlled, the reaction efficiency can be improved, and the product quality can be kept stable.

[0038] 5. Carbonization System Inlet Mother Liquor Cooler: Low-temperature cold water at around 5-20℃ is produced and sent to the carbonization system inlet mother liquor cooler to reduce the temperature of the carbonization inlet mother liquor. The reduction in the temperature of the inlet mother liquor helps to improve the initial temperature conditions of the carbonization reaction, promotes the smooth progress of the reaction, and at the same time reduces energy consumption and improves the economy of the entire carbonization system.

[0039] In summary, this invention, by cleverly integrating multiple heat sources, achieves efficient energy utilization and meets the needs of cooling and temperature reduction. It not only has the advantages of energy saving, environmental protection, and high efficiency, but can also be widely applied in multiple industrial fields, providing strong support for enterprises to reduce production costs, improve product quality, and achieve sustainable development.

Claims

1. A lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization, characterized in that: The device includes a hot alkali scrubbing tower, a furnace gas scrubbing tower, a hot water tank, a hot water heater, and a lithium bromide generator. The gas inlet of the hot alkali scrubbing tower is connected to the furnace gas outlet of the calcining furnace. The liquid inlet of the hot alkali scrubbing tower is connected to the hot alkali tank. The liquid outlet of the hot alkali scrubbing tower is connected to the hot alkali tank. The gas outlet of the hot alkali scrubbing tower is connected to the gas inlet of the furnace gas scrubbing tower. The furnace gas outlet of the furnace gas scrubbing tower is connected to a condenser. The liquid inlet of the furnace gas scrubbing tower is connected to the hot water outlet of the lithium bromide generator. The liquid outlet of the furnace gas scrubbing tower is connected to the inlet of the hot water tank. The outlet of the hot water tank is connected to the inlet of the hot water heater via a hot water pump. The outlet of the hot water heater is connected to the heating inlet of the lithium bromide generator. The cold water outlet of the lithium bromide generator is connected to a chilled water output pipeline.

2. The lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization according to claim 1, characterized in that: The lithium bromide unit includes a generator, an absorber, a condenser, and an evaporator. The outlet of the hot water heater is connected to the heating inlet of the generator, the cooling outlet of the generator is connected to the inlet of the furnace gas scrubbing tower, a heat exchanger for exchanging lithium bromide solution and heat is connected between the generator and the absorber, the steam outlet of the generator is connected to the condenser, the cooling outlet of the condenser is connected to the refrigerant water inlet of the evaporator, the steam outlet of the evaporator is connected to the absorber, and a cooling water pipeline is connected between the refrigerant water outlet and the refrigerant water inlet of the evaporator to facilitate heat exchange of the evaporator tubes to produce chilled water. A refrigerant pump is installed on the cooling water pipeline. A concentrated lithium bromide solution pump is connected between the generator and the heat exchanger, and a dilute lithium bromide solution pump is connected between the absorber and the heat exchanger.

3. The lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization according to claim 1, characterized in that: The hot water tank is connected to a boiler soft water supply pipe, and a water supply pipe and a water return pipe are connected between the hot water tank and the hot water heater.

4. The lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization according to claim 1, characterized in that: The hot water heater is a tubular heat exchanger. The tube side of the tubular heat exchanger is connected between the hot water tank and the lithium bromide generator unit. The shell side inlet of the tubular heat exchanger is connected to a low-pressure steam network or a steam condensate pipeline for calcination, dry ammonium, heavy ash, or salt production. The shell side outlet of the tubular heat exchanger is connected to a steam condensate return network or a return water pipeline for calcination, dry ammonium, heavy ash, or salt production.

5. The lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization according to claim 1, characterized in that: The hot alkaline scrubbing tower and the furnace gas scrubbing tower are each provided in two units, and the gas outlets of the two hot alkaline scrubbing towers are respectively connected to the gas inlets of the two furnace gas scrubbing towers.

6. A lithium bromide integrated refrigeration and cooling method based on the utilization of multiple heat sources, characterized in that: This method employs the lithium bromide integrated refrigeration and cooling device based on multi-heat source utilization as described in any one of claims 1-5 for refrigeration and cooling. In this method, the heat source required by the lithium bromide unit is at least one of the following heat sources: Heat source 1: Recover the heat from the furnace gas in the calcination system and convert it into hot water as a heat source for the lithium bromide unit; Heat source 2: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems as the heat source for the lithium bromide unit; Heat source 3: Using steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems to indirectly heat hot water as a heat source for the lithium bromide unit; Heat source four: Using low-pressure steam to indirectly heat hot water as a heat source for lithium bromide units.

7. The lithium bromide integrated refrigeration and cooling method based on multi-heat source utilization according to claim 6, characterized in that: In this method, the heat source process of the lithium bromide chiller unit includes: Route 1: Add a furnace gas scrubbing tower before the calcining furnace gas enters the condenser. The furnace gas, after being scrubbed by hot alkaline solution, enters the furnace gas scrubbing tower. Soft water is sprayed into the furnace gas scrubbing tower to scrub the furnace gas, recovering its heat and raising the hot water temperature to above 85°C. The furnace gas exiting the furnace gas scrubbing tower then goes to the condenser. The hot water exiting the furnace gas scrubbing tower returns to the hot water tank through a U-shaped water seal and is then pumped to the lithium bromide unit for use. The 75°C low-temperature hot water exiting the lithium bromide unit returns to the furnace gas scrubbing tower for circulation. The hot water tank is equipped with a high-level overflow port, and excess hot water returns to the condenser. In addition, a hot water heater is installed before the hot water pump outlet enters the lithium bromide unit, and low-pressure steam is connected to heat the hot water in the hot water tank. Once the hot water temperature reaches the standard, it is sent to the lithium bromide unit for use. After the system is operating normally, the steam is stopped. Route 2: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems at temperatures above 100℃ as the heat source for the lithium bromide unit, and then use the low-temperature condensate from the lithium bromide unit for subsequent processes. Route 3: Utilize the steam condensate from the calcination, dry ammonium, heavy ash, and salt production systems at temperatures above 100℃ to indirectly heat hot water via a hot water heater, which is then used as a heat source for the lithium bromide unit. The low-temperature hot water exiting the lithium bromide unit is then recirculated for further heating. Route 4: Utilize low-pressure steam to indirectly heat hot water through a hot water heater, which is then used as a heat source for the lithium bromide chiller. The low-temperature hot water exiting the lithium bromide chiller is then recirculated for further heating.

8. The lithium bromide integrated refrigeration and cooling method based on multi-heat source utilization according to claim 6, characterized in that: In this method, the lithium bromide unit includes a generator, absorber, condenser, evaporator and plate heat exchanger, and is equipped with concentrated solution pump, dilute solution pump and refrigerant pump to transport lithium bromide solution and refrigerant water in each container for circulation. It is also equipped with a vacuum pump to periodically evacuate the unit. Its working process is as follows: high-temperature hot water from the calciner gas scrubbing tower at 85°C or above is pumped to the generator to heat the dilute lithium bromide solution into a concentrated solution, while generating refrigerant vapor. The low-temperature water exiting the generator is returned to the calciner gas scrubbing tower for hot water recycling. Other heat sources adopt the same process for entering and exiting the lithium bromide unit. A heat exchanger is installed during the process of lithium bromide concentrated solution flowing from the generator back to the absorber and lithium bromide dilute solution being transported from the absorber to the generator, so that the two can exchange heat. The concentrated solution is pumped by the concentrated solution pump to the heat exchanger to exchange heat with the dilute solution. After the heat exchange, it is sent to the absorber to absorb the refrigerant vapor from the evaporator to become a dilute solution. The heat released by the absorption is carried out by the cooling water. The dilute solution is then pumped by the dilute solution pump to the heat exchanger to exchange heat with the concentrated solution before going to the generator. The solution completes the entire cycle. The refrigerant vapor generated by the generator goes to the condenser, where it is cooled by cooling water to become liquid water, i.e., low-temperature refrigerant water. Then it flows back to the low-temperature refrigerant water evaporator E, so that the refrigerant water in the evaporator is continuously replenished. The low-temperature refrigerant water in the evaporator is circulated by the refrigerant pump and exchanges heat with the chilled water in the evaporator tube side to produce low-temperature chilled water of 5-20°C. The refrigerant vapor generated by the evaporator goes to the absorber and is absorbed by the dilute solution. At this point, the refrigerant water completes the entire cycle. The cooling water used by the absorber and condenser enters the circulating water cooling tower from the unit, is cooled down, and then is pumped back to the unit for use by the cooling water pump, and so on.

9. The lithium bromide integrated refrigeration and cooling method based on multi-heat source utilization according to claim 6, characterized in that: In this method, the low-temperature chilled water produced by the lithium bromide unit is chilled water at a temperature of 5–20°C, which is used for cooling the following systems: (1) Prepare low-temperature cold water at around 5-20℃ and send it to the external cooler of the crystallization system to reduce the temperature of the cold precipitation AI; (2) Prepare low-temperature cold water at around 5-20℃ and send it to the crystallization system pre-cooling external cooler to reduce the pre-cooling temperature of the crystallization AI. (3) Prepare low-temperature cold water at around 5-20℃ and send it to the external cooler of the crystallization system to reduce the temperature of the salt-out mother II; (4) Prepare low-temperature cold water at around 5-20℃ and send it to the carbonization tower of the carbonization system to reduce the carbonization extraction temperature; (5) Prepare low-temperature cold water at around 5-20℃ and send it to the mother liquor cooler of the carbonization system to reduce the temperature of the mother liquor entering the carbonization tower.

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