Energy-saving concentrated water treatment system

Abstract

The utility model discloses an energy-saving concentrated water treatment system which comprises a waste heat recovery system and a concentrated water treatment system, high-temperature flue gas of a boiler is extracted through an induced draft fan, and the waste heat recovery system achieves heat transfer through an internal circulation medium and comprises a first heat exchanger arranged on an air duct of an outlet of the induced draft fan, a compressor and a second heat exchanger, the outer circulating medium of the shell pass of the second heat exchanger exchanges heat with the inner circulating medium of the tube pass, and then is conveyed to a concentrated water treatment system through a pipeline. According to the structure, high-temperature flue gas waste heat of the boiler is efficiently recovered, and a mechanical steam recompression technology or a multi-effect evaporation technology is combined, so that the concentrated water treatment system efficiently treats concentrated water, the external energy consumption is reduced, and the operation cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of industrial wastewater treatment technology, specifically to an energy-saving concentrated wastewater treatment system. Background Technology

[0002] In industrial production, reverse osmosis technology is widely used for water purification. However, reverse osmosis units produce a large amount of concentrate, and direct discharge of this concentrate leads to resource waste and environmental pollution. Traditional concentrate treatment methods typically consume significant amounts of energy, such as steam or electricity, resulting in high operating costs and low energy efficiency. Furthermore, the waste heat from high-temperature flue gas generated in industrial production is often not fully utilized, and direct discharge of this wastes energy. Therefore, developing a system that can efficiently utilize waste heat and treat concentrate is of great significance. Utility Model Content

[0003] To address the aforementioned technical problems, this utility model provides an energy-saving concentrated water treatment system. By recovering waste heat from high-temperature flue gas in boilers and combining mechanical steam recompression technology and multi-effect evaporation technology, it achieves efficient concentrated water treatment while reducing energy consumption and improving energy utilization.

[0004] The technical solution of this utility model is as follows: it includes a waste heat recovery system for recovering waste heat from high-temperature flue gas in a boiler, and a concentrated water treatment system that utilizes the heat provided by the waste heat recovery system to achieve concentrated water evaporation, concentration, and crystallization. The high-temperature flue gas from the boiler is extracted by an induced draft fan. The waste heat recovery system achieves heat transfer through an internal circulation medium, including a first heat exchanger installed on the outlet duct of the induced draft fan, a compressor and a second heat exchanger connected in sequence to the first heat exchanger via piping, and after the external circulation medium of the second heat exchanger exchanges heat with the internal circulation medium, it is transported to the concentrated water treatment system through a pipeline.

[0005] A further technical solution is that the first heat exchanger is a tubular heat exchanger.

[0006] A further technical solution is that the internal circulation medium can be R601 or R245FA.

[0007] A further technical solution is that the external circulation medium is circulating water, which evaporates into water vapor after heat exchange with the internal circulation medium in the second heat exchanger.

[0008] The further technical solution is as follows: steam is sent to the concentrated water treatment system through pipeline after pressure and temperature regulation. The pressure of the steam is regulated at 0.3 to 0.8 MPa and the temperature is regulated at 140°C to 180°C.

[0009] A further technical solution includes a reverse osmosis unit and a third heat exchanger. The third heat exchanger is located between the concentrate treatment system and the reverse osmosis unit. The concentrate produced by the reverse osmosis unit serves as a cold source. After heat exchange is completed in the third heat exchanger, the concentrate is transported to the concentrate treatment system through a pipeline.

[0010] A further technical solution is that the heat source in the third heat exchanger is steam condensate, and the waste heat of the steam condensate is used to preheat the concentrate.

[0011] The beneficial technical effects of this utility model are: 1) By recovering the waste heat of high-temperature flue gas from the boiler through the first heat exchanger and compressor, the energy is utilized in stages, and the heat is transferred efficiently through the internal circulation medium; the external circulation medium is transported to the concentrate treatment system after heat exchange with the internal circulation medium in the second heat exchanger, thus completing the recovery and reuse of the waste heat of high-temperature flue gas from the boiler; combined with mechanical steam recompression technology or multi-effect evaporation technology, the energy consumption of concentrate treatment is reduced; 2) The waste heat of steam condensate is used to preheat the concentrate through the third heat exchanger, further improving the energy utilization rate. The overall structure achieves efficient concentrate treatment, reduces external energy consumption, and lowers operating costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0013] Figure 2 This is a schematic diagram of the flow of heat exchange medium in the second and third heat exchangers of this utility model;

[0014] Wherein: F1, internal circulation medium; F2, external circulation medium; F3, steam condensate;

[0015] 1. Reverse osmosis unit; 2. Concentrate treatment system; 3. Exhaust fan; 4. Ductwork; 5. First heat exchanger; 6. Compressor; 7. Second heat exchanger; 8. Third heat exchanger. Detailed Implementation

[0016] In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0017] As attached Figure 1 and Figure 2As shown, the energy-saving concentrated water treatment system of this utility model includes a waste heat recovery system for recovering waste heat from high-temperature flue gas in a boiler, a reverse osmosis device 1 for purifying water quality, and a concentrated water treatment system 2 connected to the reverse osmosis device 1 via a pipeline. The concentrated water treatment system 2 can employ multi-effect evaporation technology, utilizing the secondary steam from the previous effect as the heat source for the next effect, resulting in high thermal energy utilization; or it can employ mechanical steam recompression technology, compressing and reusing the secondary steam, resulting in low energy consumption. The concentrated water produced by the reverse osmosis device 1 is transported to the concentrated water treatment system 2 via a pipeline, where it undergoes evaporation, concentration, and crystallization using the heat provided by the waste heat recovery system.

[0018] Specifically, the high-temperature flue gas from the boiler is drawn by the induced draft fan 3, and the outlet of the induced draft fan 3 is connected to the air duct 4. The waste heat recovery system is installed on the air duct of the air duct 4. The heat circulation system includes a first heat exchanger 5. Under the action of the induced draft fan 3, the flue gas after heat exchange in the first heat exchanger 5 is purified to meet safety standards and then discharged into the atmosphere through the chimney.

[0019] The waste heat recovery system also includes a compressor 6 and a second heat exchanger 7. The first heat exchanger 5, the compressor 6 and the second heat exchanger 7 are connected in sequence by piping and achieve efficient heat transfer through the internal circulation medium F1 to form a complete thermodynamic cycle system.

[0020] In this example, both the first heat exchanger 5 and the second heat exchanger 7 are tubular heat exchangers. The internal circulation medium F1 in the waste heat recovery system can be made of R601 or R245FA. High-temperature flue gas enters the shell side of the first heat exchanger and releases heat. The internal circulation medium F1 absorbs heat in the tube side of the first heat exchanger and then evaporates from a liquid state to a gaseous state. The gaseous internal circulation medium flowing out of the first heat exchanger is compressed in the compressor and then enters the second heat exchanger to release heat.

[0021] The shell-side outlet of the second heat exchanger 7 is connected to the concentrate treatment system 2. The external circulation medium F2 flowing in from the shell-side inlet of the second heat exchanger 7 exchanges heat with the internal circulation medium F1 in the second heat exchanger 7 and its temperature rises. The high-temperature external circulation medium F2 is then transported to the concentrate treatment system 2 after adjustment to meet the temperature requirements of the concentrate treatment system 2.

[0022] During operation, the internal circulation medium F1 acts as a cold source in the first heat exchanger 5. After absorbing heat from the high-temperature flue gas, it evaporates from a liquid state to a gaseous state and enters the compressor 6. The gaseous internal circulation medium F1 is compressed, and its temperature and pressure increase, forming a high-temperature and high-pressure gas. The high-temperature and high-pressure gaseous internal circulation medium F1 acts as a heat source in the second heat exchanger 7. When it exchanges heat with the external circulation medium F2, it releases heat and condenses into a liquid. The liquid internal circulation medium F1 is depressurized through the expansion valve and then returns to the first heat exchanger 5, forming a closed loop.

[0023] In this embodiment, the external circulation medium F2 is external circulation water, which is obtained from industrial water after a series of treatments. The external circulation water exchanges heat with the internal circulation medium F1 in the second heat exchanger 7, increasing its temperature and evaporating into water vapor. The water vapor is then piped to the concentrated water treatment system 2 after pressure and temperature regulation. Preferably, the water vapor pressure is regulated to 0.3–0.8 MPa, and the temperature is regulated to 140°C–180°C.

[0024] Furthermore, a third heat exchanger 8 is provided between the reverse osmosis device 1 and the concentrate treatment system 2. The heat source in the third heat exchanger 8 can be steam condensate F3, and the concentrate produced by the reverse osmosis device 1 can be used as a cold source. After heat exchange is completed in the third heat exchanger 8, the temperature of the concentrate increases. The increased temperature of the concentrate can reduce the amount of water vapor used and accelerate the evaporation rate in the concentrate treatment system 2.

[0025] Steam condensate F3 can come from the user. That is, when the user uses steam in the process engineering, the condensate is collected through the condensate recovery system. The waste heat of steam condensate F3 is fully utilized in the third heat exchanger 8 to improve energy utilization efficiency and reduce energy waste.

[0026] The structure adopts a boiler high-temperature flue gas waste heat recovery system, which achieves efficient heat recovery through the first heat exchanger 5 and compressor 6, and generates steam through the second heat exchanger 7 to meet the usage requirements of the concentrated water treatment system 2; the waste heat reuse of the third heat exchanger 8 and steam condensate F3 is combined to not only meet the needs of large-scale concentrated water treatment and pursue "zero emissions", but also to achieve comprehensive and effective utilization of energy.

[0027] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An energy efficient concentrated water treatment system, characterized by: The application relates to a waste heat recovery system for recovering waste heat of high-temperature flue gas of a boiler, a concentrated water treatment system (2) for realizing evaporation, concentration and crystallization of concentrated water by using heat provided by the waste heat recovery system; high-temperature flue gas of the boiler is extracted by an induced draft fan (3), the waste heat recovery system realizes heat transfer by internal circulation medium (F1), and comprises a first heat exchanger (5) arranged on an outlet air duct of the induced draft fan (3), a compressor (6) and a second heat exchanger (7) connected with the first heat exchanger (5) in sequence through pipelines, and external circulation medium (F2) of the second heat exchanger (7) is delivered to the concentrated water treatment system (2) through a pipeline after heat exchange with the internal circulation medium (F1).

2. The energy efficient concentrated water treatment system of claim 1, wherein: The first heat exchanger (5) is a tubular heat exchanger.

3. The energy efficient concentrated water treatment system of claim 1, wherein: The internal circulation medium (F1) can be R601 or R245FA.

4. The energy efficient concentrated water treatment system of claim 1, wherein: The external circulation medium (F2) is circulating water which is evaporated into water vapor after heat exchange with the internal circulation medium (F1) in the second heat exchanger.

5. An energy efficient concentrated water treatment system as claimed in claim 4, wherein: The water vapor is delivered to the concentrated water treatment system through a pipeline after pressure and temperature adjustment, the pressure of the water vapor is adjusted to 0.3-0.8 MPa, and the temperature of the water vapor is adjusted to 140 DEG C-180 DEG C.

6. The energy efficient concentrated water treatment system of claim 1, wherein: The application further comprises a reverse osmosis device (1) and a third heat exchanger (8), the third heat exchanger (8) is arranged between the concentrated water treatment system (2) and the reverse osmosis device (1), concentrated water generated by the reverse osmosis device (1) is used as a cold source, and the concentrated water is delivered to the concentrated water treatment system (2) through a pipeline after heat exchange in the third heat exchanger (8).

7. An energy efficient concentrated water treatment system as claimed in claim 6, wherein: The heat source in the third heat exchanger (8) is steam condensate water (F3).

Images