Low-grade heat recovery and utilization device for incinerator tail gas
By designing a device comprising a first heat exchanger, a compressor, and a working fluid storage tank, steam is generated by exchanging heat between the incinerator exhaust gas and the working fluid. After being heated by the compressor, the steam is then exchanged with cold water to generate hot water. This solves the problem of the difficulty in recovering low-grade heat from chemical plant incinerator exhaust gas and achieves low-energy heat utilization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI SMOOTHWAY ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2025-08-20
- Publication Date
- 2026-07-21
AI Technical Summary
The low-grade heat from the exhaust gas of chemical plant incinerators is difficult to recover, resulting in high energy consumption for electric heating and an inability to effectively utilize the low-grade heat.
Design an apparatus comprising a first heat exchanger, a compressor, a second heat exchanger, and a working fluid storage tank. Steam is generated by exchanging heat between the incinerator exhaust gas and the working fluid. Hot water is generated by exchanging heat between the working fluid and cold water after the compressor heats it up. The working fluid is recycled to achieve the recovery and efficient utilization of low-grade heat.
It achieves efficient recovery of low-grade heat from incinerator exhaust gas, reduces equipment investment and energy consumption, improves economic efficiency, and has wide applicability.
Smart Images
Figure CN224534280U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of energy-saving technology, and more specifically to a device for recovering and utilizing low-grade heat from incinerator exhaust gas. Background Technology
[0002] Chemical plants often generate organic waste gases, which require treatment to meet emission standards before being released. For example, Regenerative Thermal Oxidizers (RTOs) are an effective method for reducing VOCs in exhaust gases; however, the low temperature of the exhaust gas from an RTO furnace, after heat storage, makes it difficult to recover low-grade heat. On the other hand, chemical plants often require hot water as a heat source, such as for insulation and melting solid media. Without a steam supply, energy is often obtained through electric heating to raise the water to a specified temperature. In such cases, as the number of users increases, a significant amount of electricity is needed to heat the water, resulting in high energy consumption. Especially for products requiring low energy consumption, it is crucial to reduce production costs through specific energy-saving methods.
[0003] Therefore, there is an urgent need for a device for recovering and utilizing low-grade heat from incinerator exhaust gas to address the shortcomings of existing technologies. Utility Model Content
[0004] In view of the above problems, the purpose of this utility model is to provide a device for recovering and utilizing low-grade heat from incinerator exhaust gas. This device can recover low-grade heat from incinerator exhaust gas and heat water to obtain hot water after heat exchange. It has the advantages of low equipment investment, wide applicability, and high economy.
[0005] To achieve the above objectives, this utility model provides a low-grade heat recovery and utilization device for incinerator tail gas, comprising a device body, which includes a first heat exchanger, a compressor, a second heat exchanger, and a working fluid storage tank. The first heat exchanger has a tail gas inlet, a tail gas outlet, a working fluid inlet A, and a working fluid outlet A. The second heat exchanger has a working fluid inlet B, a working fluid outlet B, a cold water inlet, and a hot water outlet. The working fluid outlet A of the first heat exchanger is connected to the inlet of the compressor, the outlet of the compressor is connected to the working fluid inlet B of the second heat exchanger, the working fluid outlet B of the second heat exchanger is connected to the inlet of the working fluid storage tank, and the outlet of the working fluid storage tank is connected to the working fluid inlet A of the first heat exchanger. A pressure reducing device is also provided between the first heat exchanger and the working fluid storage tank. The working fluid in the working fluid storage tank is depressurized and vaporized by the pressure reducing device and then enters the first heat exchanger to exchange heat with the incinerator tail gas.
[0006] Compared with existing technologies, this invention uses a first heat exchanger to exchange heat between incinerator exhaust gas and working fluid to obtain working fluid steam. A compressor further compresses and heats the working fluid steam to obtain a working fluid with high-grade heat. A second heat exchanger then exchanges heat between the high-grade heat working fluid and cold water to obtain hot water. The working fluid can be stored in a working fluid storage tank and depressurized and vaporized by a pressure-reducing device for further recycling. The hot water can be used in various user workshops. Therefore, this invention's recycling device can recover low-grade heat from incinerator exhaust gas and use this low-grade heat to heat water, offering advantages such as low equipment investment, wide applicability, and high economic efficiency.
[0007] Furthermore, the incinerator is an RTO incinerator or an RCO incinerator.
[0008] Furthermore, the pressure reducing device is an expansion valve.
[0009] Furthermore, the first heat exchanger is a tubular heat exchanger or a plate heat exchanger.
[0010] Furthermore, the second heat exchanger is a plate heat exchanger.
[0011] Furthermore, the cold water inlet of the second heat exchanger is connected to the cold water input pipe.
[0012] Furthermore, the hot water outlet of the second heat exchanger is connected to the hot water output pipe.
[0013] Furthermore, the exhaust gas inlet of the first heat exchanger is connected to the exhaust gas delivery pipe of the incinerator.
[0014] Furthermore, the exhaust outlet of the first heat exchanger is connected to the exhaust pipe. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of a low-grade heat recovery and utilization device for incinerator exhaust gas according to the present invention.
[0016] Component symbol explanation: 100-Purpose unit, 10-First heat exchanger, 11-Tail gas inlet, 12-Tail gas outlet, 13-Working fluid inlet A, 14-Working fluid outlet A, 20-Compressor, 30-Second heat exchanger, 31-Working fluid inlet B, 32-Working fluid outlet B, 33-Cold water inlet, 34-Hot water outlet, 40-Working fluid storage tank, 50-Pressure reducing device, 60-Incinerator tail gas conveying pipe, 70-Tail gas discharge pipe, 80-Cold water input pipe, 90-Hot water output pipe. Detailed Implementation
[0017] To better illustrate the purpose, technical solution, and beneficial effects of this utility model, the following description, in conjunction with the accompanying drawings, will further explain this utility model. It should be noted that the embodiments described below are only some, not all, of the embodiments of this utility model.
[0018] The terms “comprising,” “including,” etc., as used herein indicate the presence of the described features, steps, operations, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components. All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification and not in an idealized or overly rigid way.
[0019] In this document, unless otherwise specified, directional terms such as "up," "down," "left," "right," "inner," and "outer" are used to indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device, element, or component referred to must have a specific orientation, or be constructed or operated in a specific orientation. It should be understood that when the absolute position of the described object changes, the relative positional relationship they represent may also change accordingly. Therefore, these directional terms should not be construed as limitations on the present invention.
[0020] Combination Figure 1 As shown, this utility model discloses a low-grade heat recovery and utilization device for incinerator tail gas, including a device body 100. The device body 100 includes a first heat exchanger 10, a compressor 20, a second heat exchanger 30, and a working fluid storage tank 40. The first heat exchanger 10 is provided with a tail gas inlet 11, a tail gas outlet 12, a working fluid inlet A 13, and a working fluid outlet A 14. The second heat exchanger 30 is provided with a working fluid inlet B 31, a working fluid outlet B 32, a cold water inlet 33, and a hot water outlet 34. The working fluid outlet A 14 of the first heat exchanger 10 is connected to the inlet (not shown in the figure) of the compressor 20, the outlet (not shown in the figure) of the compressor 20 is connected to the working fluid inlet B 31 of the second heat exchanger 30, the working fluid outlet B 32 of the second heat exchanger 30 is connected to the inlet (not shown in the figure) of the working fluid storage tank 40, and the outlet (not shown in the figure) of the working fluid storage tank 40 is connected to the working fluid inlet A 13 of the first heat exchanger 10. A pressure reducing device 50 is also provided between the first heat exchanger 10 and the working fluid storage tank 40. The working fluid (not shown in the figure) in the working fluid storage tank 40 is depressurized and vaporized by the pressure reducing device 50 and then enters the first heat exchanger 10 to exchange heat with the incinerator exhaust gas (not shown in the figure).
[0021] In this invention, the first heat exchanger 10 is used to exchange heat between the incinerator exhaust gas and the working fluid. The low-grade heat of the incinerator exhaust gas is used to heat the working fluid and cause it to evaporate and vaporize, thereby fully utilizing the low-grade heat of the incinerator exhaust gas. Specifically, the incinerator (not shown in the figure) can be an RTO incinerator, or an RCO incinerator, or other furnaces that generate flue gas. The temperature of the incinerator exhaust gas is 40℃~70℃. The working fluid has a boiling point of 0℃~-40℃ at an operating pressure of 0.2MPa~1.0MPa, and the working fluid can be selected from at least one of R22 Freon, R32 Freon, and R134a Freon. The first heat exchanger 10 is a tubular heat exchanger (not shown in the figure) or a plate heat exchanger (not shown in the figure). The exhaust gas inlet 11 of the first heat exchanger 10 is connected to the incinerator exhaust gas delivery pipe 60, through which the incinerator exhaust gas enters the first heat exchanger 10. The exhaust gas outlet 12 of the first heat exchanger 10 is connected to the exhaust gas discharge pipe 70, through which the remaining exhaust gas and other substances after heat exchange in the first heat exchanger 10 are discharged from the device. The first heat exchanger 10 is also provided with a working fluid replenishment port (not shown in the figure). When working fluid needs to be replenished from the outside, the working fluid can enter the first heat exchanger 10 through the working fluid replenishment port to participate in heat exchange.
[0022] In this invention, the compressor 20 is used to compress and heat the working fluid from the first heat exchanger 10, thereby obtaining high-pressure working fluid steam with higher-grade heat. In this invention, high-grade heat specifically refers to heat with higher energy quality compared to the aforementioned low-grade heat. The inlet pressure of the compressor 20 is controlled at 0.2~1.0 MPa, and the outlet pressure of the compressor 20 is controlled at 1.5~2.5 MPa. After compression, the temperature of the working fluid rises to 70℃~100℃.
[0023] In this invention, the second heat exchanger 30 is used to exchange heat between the working fluid and cold water, that is, to heat the cold water using the high-grade heat of the working fluid. Specifically, the cold water inlet 33 of the second heat exchanger 30 is connected to the cold water input pipe 80, and the hot water outlet 34 of the second heat exchanger 30 is connected to the hot water output pipe 90. Cold water enters the second heat exchanger 30 through the cold water inlet 33 from the cold water input pipe 80 and exchanges heat with the working fluid after it has been compressed and heated by the compressor 20. During the heat exchange process, the temperature of the working fluid decreases and partially condenses into liquid, while the temperature of the cold water increases and becomes hot water. After the heat exchange is completed, the working fluid enters the working fluid storage tank 40 through the working fluid outlet B, and the hot water is output through the hot water outlet pipe and distributed to various workshops for use. The second heat exchanger 30 can be a plate heat exchanger.
[0024] In this invention, the working fluid storage tank 40 is used to store the working fluid after heat exchange in the second heat exchanger 30. The pressure reducing device 50 is used to further reduce the pressure of the working fluid; the pressure reducing device 50 is an expansion valve (not shown in the figure). After the working fluid in the storage tank 40 is depressurized and vaporized by the expansion valve, it enters the first heat exchanger 10 and exchanges heat with the incinerator exhaust gas, starting a new heat exchange process.
[0025] In this utility model, the working fluid outlet A14 of the first heat exchanger 10 is connected to the inlet of the compressor 20 via a pipe, the outlet of the compressor 20 is connected to the working fluid inlet B31 of the second heat exchanger 30 via a pipe, the working fluid outlet B32 of the second heat exchanger 30 is connected to the inlet of the working fluid storage tank 40 via a pipe, and the outlet of the working fluid storage tank 40 is connected to the working fluid inlet A13 of the first heat exchanger via a pipe.
[0026] In operation, the low-grade heat recovery and utilization device for incinerator exhaust gas of this utility model allows the incinerator exhaust gas to enter the first heat exchanger 10 via the incinerator exhaust gas delivery pipe 60 and exhaust gas inlet 11. In the first heat exchanger 10, the gas exchanges heat with the working fluid. The remaining exhaust gas is discharged through the exhaust gas discharge pipe 70. The working fluid is heated and vaporized in the first heat exchanger 10 and enters the compressor 20 through the working fluid outlet A 14. The working fluid is further compressed and heated in the compressor 20. The compressed and heated working fluid enters the second heat exchanger 30 through the working fluid inlet B 31. Simultaneously, cold water enters the second heat exchanger 30 via the cold water input pipe 80 and cold water inlet 33. The working fluid and cold water exchange heat in the second heat exchanger 30, raising the temperature of the cold water to hot water, which is then output to users in various workshops through the hot water output pipe 90. The working fluid cools down and is partially condensed into liquid, exiting through the working fluid outlet B 14. 32 enters the working fluid storage tank 40. The working fluid in the working fluid storage tank 40 is depressurized by the pressure reducing device 50 and then vaporized again into low-pressure steam, which then enters the first heat exchanger 10 for recycling.
[0027] The following describes the incinerator exhaust gas low-grade heat recovery and utilization device of this utility model in further detail with reference to specific embodiments.
[0028] Example 1
[0029] R22 Freon is used as the working fluid, with a flow rate of 5.5 tons / hour. The RTO incinerator tail gas temperature is 40℃. The incinerator tail gas enters the first heat exchanger 10 through the tail gas delivery pipe 60 and tail gas inlet 11, where it heats the working fluid to 10℃ and vaporizes at a pressure of 0.5MPa. The vaporized working fluid is then compressed by the compressor 20 into a high-pressure gas of 2MPa, while its temperature rises to 98.7℃. This compressed gas then heats cold water to 80℃ through the second heat exchanger 30. The heated water is then sent to various workshop users through the hot water outlet pipe 90. After heat exchange, the working fluid liquefies and enters the working fluid storage tank 40 through the working fluid outlet B 32. The temperature drops to 50℃, and after the liquid level is controlled, it is depressurized by the expansion valve and vaporized again into gas at a temperature of 0℃, before returning to the first heat exchanger 10 for recycling.
[0030] Using the low-grade heat recovery and utilization device for incinerator flue gas of this invention, the compressor consumes 82 kWh per hour. If hot water is directly heated electrically, the hourly power consumption is 300 kWh. This significantly reduces energy consumption.
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.
Claims
1. A device for recovering and utilizing low-grade heat from incinerator flue gas, comprising a device body, characterized in that, The device body includes a first heat exchanger, a compressor, a second heat exchanger, and a working fluid storage tank. The first heat exchanger has an exhaust gas inlet, an exhaust gas outlet, a working fluid inlet A, and a working fluid outlet A. The second heat exchanger has a working fluid inlet B, a working fluid outlet B, a cold water inlet, and a hot water outlet. The working fluid outlet A of the first heat exchanger is connected to the inlet of the compressor, the outlet of the compressor is connected to the working fluid inlet B of the second heat exchanger, the working fluid outlet B of the second heat exchanger is connected to the inlet of the working fluid storage tank, and the outlet of the working fluid storage tank is connected to the working fluid inlet A of the first heat exchanger. A pressure reducing device is also provided between the first heat exchanger and the working fluid storage tank. The working fluid in the working fluid storage tank is depressurized and vaporized by the pressure reducing device and then enters the first heat exchanger to exchange heat with the exhaust gas from the incinerator.
2. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The incinerator is an RTO incinerator or an RCO incinerator.
3. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The pressure reducing device is an expansion valve.
4. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The first heat exchanger is a tubular heat exchanger or a plate heat exchanger.
5. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The second heat exchanger is a plate heat exchanger.
6. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The cold water inlet of the second heat exchanger is connected to the cold water input pipe.
7. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The hot water outlet of the second heat exchanger is connected to the hot water output pipe.
8. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The exhaust gas inlet of the first heat exchanger is connected to the exhaust gas delivery pipe of the incinerator.
9. The incinerator flue gas low-grade heat recovery and utilization device as described in claim 1, characterized in that, The exhaust outlet of the first heat exchanger is connected to the exhaust pipe.