Lithium bromide refrigeration system based on waste heat of boiler flue gas

Abstract

The utility model belongs to the technical field of waste heat recovery device, concretely relates to a lithium bromide refrigeration system based on boiler flue gas waste heat, including hot water type lithium bromide unit, hot water pump, refrigerated water pump, hot water heater, hot water heat exchanger, first pressure tank, second pressure tank and deaerator, the tube side of hot water heater, hot water type lithium bromide unit, hot water pump, the tube side of hot water heat exchanger constitute hot water circulating system, hot water type lithium bromide unit, refrigerated water pump constitute refrigerated water circulating system, and the shell side of hot water heat exchanger is connected with desalted water pipe, and the shell side export of hot water heat exchanger is connected with deaerator import and the water inlet of first pressure tank, and desalted water pipe is connected with the water inlet of second pressure tank, and first pressure tank is connected with hot water circulating system, and second pressure tank is connected with refrigerated water circulating system. The utility model discloses through hot water heat exchanger control hot water import temperature, and will boiler flue gas waste heat be used for preheating boiler water, avoid heat waste, prevent machine pump cavitation simultaneously.

Description

Technical Field

[0001] This utility model belongs to the technical field of waste heat recovery devices, specifically relating to a lithium bromide refrigeration system based on waste heat from boiler flue gas. Background Technology

[0002] Boilers are widely used in industry. After the high-temperature flue gas from boilers is utilized by superheaters, evaporators, and economizers, a significant amount of heat is still released into the atmosphere, resulting in energy waste. Simultaneously, industrial production has a large demand for chilled water, and hot-water lithium bromide chillers are commonly used in refrigeration. Recovering waste heat from boiler flue gas using hot-water lithium bromide chillers is a common industrial technique. Hot-water lithium bromide chillers require continuous adjustment of the inlet hot water flow rate or temperature based on fluctuations in the process unit load. However, for hot water systems with fixed heat sources and closed-loop circulation, adjusting the hot water flow rate is often inconvenient because an excessively low flow rate would cause the hot water temperature to rise too high, making it unusable by the hot-water lithium bromide chiller. Temperature adjustment is typically achieved through heat exchange in the circulating water; if this exchanged heat is not utilized, it results in heat waste.

[0003] Furthermore, the hot water and chilled water systems of hot water-type lithium bromide chiller units generally employ closed-loop circulation, which inevitably results in some pressure loss during operation. Excessively low operating pressure can easily cause cavitation in the pumps, especially in hot water systems where the high temperature of the hot water and the low pump inlet pressure greatly increase the risk of cavitation. Therefore, it is necessary to design a refrigeration system that can efficiently utilize waste heat and is safe and stable. Utility Model Content

[0004] The present invention aims to provide a lithium bromide refrigeration system based on waste heat from boiler flue gas to solve the problems of heat waste and easy cavitation of pumps.

[0005] To achieve the above objectives, the present invention provides a lithium bromide refrigeration system based on boiler flue gas waste heat, comprising a hot water type lithium bromide chiller, a hot water pump, a chilled water pump, and a hot water heater, and further comprising a hot water heat exchanger, a first pressure stabilizing tank, a second pressure stabilizing tank, and a deaerator. The shell-side inlet of the hot water heat exchanger is connected to a demineralized water pipe, and the shell-side outlet of the hot water heat exchanger is connected to the inlet of the deaerator via a pipe. The hot water outlet of the hot water type lithium bromide chiller is connected to the inlet of the hot water heater via a pipe, the outlet of the hot water heater is connected to the tube-side inlet of the hot water heat exchanger via a pipe, and the tube-side outlet of the hot water heat exchanger is connected to the hot water inlet of the hot water type lithium bromide chiller via a pipe. The hot water pump is located on the pipe between the hot water heat exchanger and the hot water type lithium bromide chiller. The chilled water outlet of the hot water type lithium bromide chiller... A chilled water circulation pipe is connected, and a chilled water pump is installed on the chilled water circulation pipe. The pipe between the hot water heat exchanger and the hot water pump is connected to the outlet of the first pressure stabilizing tank via a pressure replenishment pipe I. The pipe between the hot water heat exchanger and the deaerator is connected to the inlet of the first pressure stabilizing tank via a water replenishment pipe I, and a valve I is installed on the water replenishment pipe I to control its on / off state. The chilled water circulation pipe between the hot water type lithium bromide unit and the chilled water pump is connected to the outlet of the second pressure stabilizing tank via a pressure replenishment pipe II. A water replenishment pipe II is connected to the demineralized water pipe and is connected to the inlet of the second pressure stabilizing tank. A valve II is installed on the water replenishment pipe II to control its on / off state. Low-pressure nitrogen branch pipes are connected to the air inlets of both the first and second pressure stabilizing tanks. Regulating valves are installed on both the low-pressure nitrogen branch pipe and the demineralized water pipe.

[0006] The working principle and beneficial effects of this scheme are as follows: In this scheme, the boiler flue gas enters the shell side of the hot water heater, transferring the waste heat of the boiler flue gas to the hot water. The hot water exchanges heat with the demineralized water in the hot water heat exchanger, and the temperature of the hot water decreases. The amount of demineralized water is controlled by the regulating valve to regulate the heat exchange and control the hot water temperature so that it meets the inlet hot water temperature of the hot water type lithium bromide unit. The demineralized water that has absorbed heat and increased in temperature enters the deaerator to achieve the purpose of preheating the boiler water, reducing the steam consumption of the deaerator for deoxygenation, and avoiding heat waste.

[0007] Furthermore, this solution utilizes a first pressure stabilizing tank to stabilize the hot water circulation system of the hot water type lithium bromide unit, and a second pressure stabilizing tank to stabilize the chilled water circulation system of the hot water type lithium bromide unit, preventing pump cavitation. Simultaneously, heated demineralized water is supplied to the first pressure stabilizing tank through water supply pipe I, reducing the cold impact on the hot water circulation system during the pressure stabilization process. Room temperature demineralized water is supplied to the second pressure stabilizing tank through water supply pipe II, ensuring the long-term operation of both the first and second pressure stabilizing tanks.

[0008] Optionally, a connecting pipe is provided between the pressure replenishing pipe I and the pressure replenishing pipe II for connecting the pressure replenishing pipe I and the pressure replenishing pipe II. A valve III is provided on the connecting pipe, the pressure replenishing pipe I and the pressure replenishing pipe II. The valve III on the pressure replenishing pipe I is located between the connection point of the pressure replenishing pipe I and the connecting pipe and the first pressure stabilizing tank. The valve III on the pressure replenishing pipe II is located between the connection point of the pressure replenishing pipe II and the connecting pipe and the second pressure stabilizing tank.

[0009] In this scheme, pressure replenishing pipe I and pressure replenishing pipe II are connected by a connecting pipe. Thus, when the first pressure stabilizing tank (second pressure stabilizing tank) is not working, the second pressure stabilizing tank (first pressure stabilizing tank) can replenish the pressure of the hot water circulation system and the chilled water circulation system of the hot water type lithium bromide unit. That is, at this time, the hot water circulation system and the chilled water circulation system share a pressure stabilizing tank to prevent pump cavitation.

[0010] Optionally, the low-pressure nitrogen branch pipe is connected to a low-pressure nitrogen main pipe.

[0011] In this scheme, the low-pressure nitrogen in the low-pressure nitrogen main pipe enters the first pressure stabilizing tank and the second pressure stabilizing tank through two low-pressure nitrogen branch pipes. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a lithium bromide refrigeration system based on waste heat from boiler flue gas in Embodiment 1 of this utility model.

[0013] Figure 2 This is a schematic diagram of a lithium bromide refrigeration system based on waste heat from boiler flue gas in Embodiment 1 of this utility model. Detailed Implementation

[0014] The following detailed description illustrates the specific implementation method:

[0015] The markings in the accompanying drawings include: 1. Hot water type lithium bromide unit; 2. Hot water pump; 3. Chilled water pump; 4. Hot water heater; 5. Hot water heat exchanger; 6. First pressure stabilizing tank; 7. Second pressure stabilizing tank; 8. Deaerator; 9. Demineralized water pipe; 10. Chilled water circulation pipe; 11. Pressure replenishment pipe I; 12. Water replenishment pipe I; 13. Pressure replenishment pipe II; 14. Water replenishment pipe II; 15. Valve II; 16. Low-pressure nitrogen branch pipe; 17. Low-pressure nitrogen main pipe; 18. Regulating valve; 19. Connecting pipe; 20. Valve III; 21.

[0016] Example 1

[0017] This embodiment is basically as follows: Figure 1The diagram shows a lithium bromide refrigeration system based on boiler flue gas waste heat, comprising a hot water type lithium bromide unit 1, a hot water pump 2, a chilled water pump 3, a hot water heater 4, a hot water heat exchanger 5, a first pressure stabilizing tank 6, a second pressure stabilizing tank 7, and a deaerator 8. The shell-side inlet of the hot water heat exchanger 5 is connected to a demineralized water pipe 9, and the shell-side outlet of the hot water heat exchanger 5 is connected to the inlet of the deaerator 8 via a pipe. The hot water outlet of the hot water type lithium bromide unit 1 is connected to the tube-side inlet of the hot water heater 4 via a pipe, the tube-side outlet of the hot water heater 4 is connected to the tube-side inlet of the hot water heat exchanger 5 via a pipe, and the tube-side outlet of the hot water heat exchanger 5 is connected to the hot water inlet of the hot water type lithium bromide unit 1 via a pipe. The hot water pump 2 is located on the pipe between the hot water heat exchanger 5 and the hot water type lithium bromide unit 1. The chilled water outlet of the hot water type lithium bromide unit 1 is connected to a chilled water circulation pipe 10, and the chilled water pump 3 is located on the chilled water circulation pipe 10.

[0018] The pipe between the hot water heat exchanger 5 and the hot water pump 2 is connected to the outlet of the first pressure stabilizing tank 6 via a pressure-reducing pipe I11. The pipe between the hot water heat exchanger 5 and the deaerator 8 is connected to the inlet of the first pressure stabilizing tank 6 via a water-replenishing pipe I12, and a valve I13 is installed on the water-replenishing pipe I12 to control its on / off state. The chilled water circulation pipe 10 between the hot water type lithium bromide unit 1 and the chilled water pump 3 is connected to the outlet of the second pressure stabilizing tank 7 via a pressure-replenishing pipe II14. A water-replenishing pipe II15 is connected to the demineralized water pipe 9 and is connected to the inlet of the second pressure stabilizing tank 7. A valve II16 is installed on the water-replenishing pipe II15 to control its on / off state. The air inlets of the first pressure stabilizing tank 6 and the second pressure stabilizing tank 7 are both connected to low-pressure nitrogen branch pipes 17, which are connected to a low-pressure nitrogen main pipe 18. Regulating valves 19 are installed on both the low-pressure nitrogen branch pipe 17 and the demineralized water pipe 9.

[0019] In operation, in the hot water circulation system of the hot water type lithium bromide unit 1, the hot water flowing out of the hot water outlet of the unit enters the tube side of the hot water heater 4, where it exchanges heat with the high-temperature flue gas from the boiler in the shell side of the heater 4 to obtain high-temperature hot water. This high-temperature hot water then enters the tube side of the hot water heat exchanger 5. Simultaneously, demineralized water enters the shell side of the heat exchanger 5 via the demineralized water pipe 9, where it exchanges heat with the demineralized water, lowering its temperature to meet the inlet hot water temperature requirement of the hot water type lithium bromide unit 1, thus achieving hot water circulation. The demineralized water, after being heated, enters the deaerator 8 to preheat the boiler water, reducing steam consumption in the deaerator 8. Furthermore, the regulating valve 19 on the demineralized water pipe 9 can adjust the amount of demineralized water in the hot water heat exchanger 5, thereby controlling the inlet hot water temperature of the hot water type lithium bromide unit 1 during the hot water circulation process.

[0020] During the hot water circulation process, when pressure loss occurs, water in the first pressure stabilizing tank 6 is replenished to the hot water circulation system through the pressure replenishment pipe I11, thereby stabilizing the pressure of the hot water circulation system and preventing cavitation of the hot water pump 2. Furthermore, when the water level in the first pressure stabilizing tank 6 is too low, valve I13 on the water replenishment pipe I12 opens, allowing demineralized water from the shell side of the hot water heat exchanger 5 to enter the first pressure stabilizing tank 6 through the water replenishment pipe I12, thus replenishing the first pressure stabilizing tank 6 and minimizing any cold impact on the hot water circulation system during the pressure stabilization process.

[0021] When pressure loss occurs during the chilled water circulation process of the hot water type lithium bromide unit 1, water in the second pressure stabilizing tank 7 is supplied to the chilled water circulation pipe 10 through the pressure replenishment pipe II 14, thereby stabilizing the pressure of the chilled water circulation system and preventing cavitation of the chilled water pump 3. Furthermore, when the water level in the second pressure stabilizing tank 7 is too low, valve II 16 on the water replenishment pipe II 15 opens, and demineralized water enters the second pressure stabilizing tank 7 through the water replenishment pipe II 15, thus replenishing the second pressure stabilizing tank 7.

[0022] Example 2

[0023] The difference between this embodiment and Embodiment 1 is that: Figure 2 As shown, in this embodiment, a connecting pipe 20 is provided between the pressure replenishing pipe I11 and the pressure replenishing pipe II14 to connect the pressure replenishing pipe I11 and the pressure replenishing pipe II14. A valve III21 is provided on the connecting pipe 20, the pressure replenishing pipe I11 and the pressure replenishing pipe II14. The valve III21 on the pressure replenishing pipe I11 is located between the connection point of the pressure replenishing pipe I11 and the connecting pipe 20 and the first pressure stabilizing tank 6. The valve III21 on the pressure replenishing pipe II14 is located between the connection point of the pressure replenishing pipe II14 and the connecting pipe 20 and the second pressure stabilizing tank 7.

[0024] Thus, in this embodiment, the first pressure stabilizing tank 6 and the second pressure stabilizing tank 7 can simultaneously stabilize the pressure of both the hot water circulation system and the chilled water circulation system. When the first pressure stabilizing tank 6 is not in operation (e.g., during a malfunction or maintenance), valve III 21 on the pressure replenishing pipe I 11 is closed, and valve III 21 on the connecting pipe 20 is open (valve III 21 on the pressure replenishing pipe II 14 is normally open). In this way, the demineralized water in the second pressure stabilizing tank 7 can enter the hot water circulation system and the chilled water circulation pipe 10, i.e., the second pressure stabilizing tank 7 stabilizes the pressure of both systems. When the first pressure stabilizing tank 6 is ready to operate, valve III 21 on the pressure replenishing pipe I 11 is opened, and valve III 21 on the connecting pipe 20 is closed.

[0025] When the second pressure stabilizing tank 7 is not in operation, valve III21 on pressure replenishing pipe II14 is closed, and valve III21 on connecting pipe 20 is opened (valve III21 on pressure replenishing pipe I11 is normally open). In this way, the demineralized water in the first pressure stabilizing tank 6 can enter the hot water circulation system and the chilled water circulation pipe 10, meaning that the first pressure stabilizing tank 6 stabilizes the pressure of the hot water circulation system and the chilled water circulation system. When the second pressure stabilizing tank 7 is ready to operate, valve III21 on pressure replenishing pipe II14 is opened, and valve III21 on connecting pipe 20 is closed.

[0026] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness or practicality of this utility model. The specific embodiments described in the specification can be used to interpret the claims.

Claims

1. A lithium bromide refrigeration system based on boiler flue gas waste heat, comprising a hot water type lithium bromide chiller, a hot water pump, a chilled water pump, and a hot water heater, characterized in that: It also includes a hot water heat exchanger, a first pressure stabilizing tank, a second pressure stabilizing tank, and a deaerator. The shell-side inlet of the hot water heat exchanger is connected to a demineralized water pipe, and the shell-side outlet of the hot water heat exchanger is connected to the inlet of the deaerator via a pipeline. The hot water outlet of the hot water type lithium bromide unit is connected to the tube-side inlet of the hot water heater via a pipeline, the tube-side outlet of the hot water heater is connected to the tube-side inlet of the hot water heat exchanger via a pipeline, and the tube-side outlet of the hot water heat exchanger is connected to the hot water inlet of the hot water type lithium bromide unit via a pipeline. A hot water pump is installed on the pipeline between the hot water heat exchanger and the hot water type lithium bromide unit. The chilled water outlet of the hot water type lithium bromide unit is connected to a chilled water circulation pipe, and a chilled water pump is installed on the chilled water circulation pipe. The pipe between the heat exchanger and the hot water pump is connected to the outlet of the first pressure stabilizing tank via a pressure-replenishing pipe I. The pipe between the hot water heat exchanger and the deaerator is connected to the inlet of the first pressure stabilizing tank via a water-replenishing pipe I, and a valve I for controlling the on / off state of the water-replenishing pipe I is installed on the water-replenishing pipe I. The chilled water circulation pipe between the hot water type lithium bromide unit and the chilled water pump is connected to the outlet of the second pressure stabilizing tank via a pressure-replenishing pipe II. A water-replenishing pipe II is connected to the demineralized water pipe, and the water-replenishing pipe II is connected to the inlet of the second pressure stabilizing tank. A valve II for controlling the on / off state of the water-replenishing pipe II is installed on the water-replenishing pipe II. The air inlets of both the first and second pressure stabilizing tanks are connected to low-pressure nitrogen branch pipes, and regulating valves are installed on both the low-pressure nitrogen branch pipes and the demineralized water pipes.

2. The lithium bromide refrigeration system based on boiler flue gas waste heat according to claim 1, characterized in that: A connecting pipe is provided between the pressure replenishing pipe I and the pressure replenishing pipe II to connect the two pipes. A valve III is provided on the connecting pipe, the pressure replenishing pipe I, and the pressure replenishing pipe II. The valve III on the pressure replenishing pipe I is located between the connection point of the pressure replenishing pipe I and the connecting pipe and the first pressure stabilizing tank. The valve III on the pressure replenishing pipe II is located between the connection point of the pressure replenishing pipe II and the connecting pipe and the second pressure stabilizing tank.

3. The lithium bromide refrigeration system based on boiler flue gas waste heat according to claim 1 or 2, characterized in that: The low-pressure nitrogen branch pipe is connected to the low-pressure nitrogen main pipe.

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