A waste steam recovery device

Abstract

This utility model belongs to the field of thermoelectric equipment technology, specifically relating to a waste steam recovery device. Based on a heat exchange device, it recovers the heat energy of waste steam from a deaerator. The device includes a first heat exchanger and a condensate tank. The heat exchanger recovers heat from the waste steam of the deaerator to heat the incoming water. The condensate tank collects the heated incoming water, and its outlet is connected to the inlet of the deaerator. This utility model recovers heat energy from the waste steam of the deaerator using a heat exchanger to heat the incoming water, thereby increasing the temperature of the incoming water and reducing the heat consumed per unit flow rate of incoming water within the deaerator. This reduces energy consumption when the flow rate demand is constant and reduces the equipment investment required for the heat exchanger when the flow rate demand increases.

Description

Technical Field

[0001] This utility model belongs to the field of thermoelectric equipment technology, specifically relating to a waste steam recovery device. Background Technology

[0002] The deaerator in a thermal power plant is a key piece of equipment in the boiler feedwater system. Its main function is to remove dissolved oxygen and other non-condensable gases from the water to prevent equipment corrosion and reduced heat transfer efficiency. The principle is to heat ambient temperature demineralized water (usually preheated) to its saturation temperature (approximately 104–158℃, corresponding to a pressure of 0.02–0.6 MPa), reducing oxygen solubility to near zero. The released gas is then discharged with a small amount of steam (exhaust steam).

[0003] The exhaust steam from a deaerator is typically 0.1–0.3% of the total influent flow rate, and its temperature is close to the steam saturation temperature at the corresponding pressure. It contains a large amount of thermal energy. In existing equipment, the exhaust steam from the deaerator is usually directly discharged into the atmosphere, resulting in energy waste. Utility Model Content

[0004] In view of this, the present invention provides a waste steam recovery device, which is equipped with a heat exchanger to recover the heat of the waste steam that should be discharged into the atmosphere by the deaerator, and use it to preheat the water in the deaerator, thereby reducing the energy consumption of the deaerator or increasing the working efficiency of the deaerator.

[0005] To achieve the above technical solution, the specific technical solution adopted by this utility model is as follows:

[0006] A waste steam recovery device, which recovers the thermal energy of waste steam from a deaerator based on a heat exchange device, the waste steam recovery device comprising:

[0007] A deaerator is used to remove dissolved oxygen from demineralized water and generate high-temperature, high-pressure exhaust steam.

[0008] The first heat exchanger has a heat source inlet connected to the high-temperature and high-pressure exhaust steam, a heat source outlet connected to a condensate tank, and a cold source inlet connected to normal-temperature demineralized water, and a cold source outlet connected to the water inlet of the deaerator.

[0009] Wherein: the outlet of the condensate tank is connected to the inlet of the deaerator.

[0010] In this embodiment, in order to controllably allow the exhaust steam from the deaerator to enter the heat exchanger, the steam outlet of the deaerator is connected to one end of the first exhaust steam pipeline, one end of the first pneumatic valve, and one end of the first shut-off valve; the other end of the first pneumatic valve and the other end of the first shut-off valve are connected to the first exhaust steam device.

[0011] Furthermore, in order to control the flow direction of exhaust steam, the first shut-off valve is a DN150 shut-off valve.

[0012] Furthermore, to ensure the normal operation of the first exhaust steam pipeline, the other end of the first exhaust steam pipeline is connected to the first heat exchanger; the first exhaust steam pipeline is a DN65 pipeline, and a DN100 shut-off valve, a DN100 check valve, a pressure gauge and a thermometer are installed on the pipeline.

[0013] Furthermore, in order to ensure the normal operation of the ambient temperature demineralized water pipeline, the ambient temperature demineralized water is transported to the first heat exchanger via a DN65 ambient temperature demineralized water pipeline. The ambient temperature demineralized water pipeline is equipped with a DN65 shut-off valve, a DN65 pneumatic valve, a DN65 solenoid valve, a pressure gauge, and a thermometer.

[0014] Furthermore, to ensure the flow rate of the medium, the first heat exchanger and the condensate tank, as well as the condensate tank and the deaerator, are connected by a normal temperature demineralized water pipeline; the diameter of the normal temperature demineralized water pipeline between the first heat exchanger and the condensate tank is DN65, and the diameter of the normal temperature demineralized water pipeline between the condensate tank and the deaerator is DN125.

[0015] To further improve energy efficiency, the waste steam recovery device also includes a condensate expansion tank; the inlet of the condensate expansion tank is connected to the boiler outlet water.

[0016] Furthermore, in order to improve energy efficiency, the steam outlet of the hydrophobic expansion tank is connected to the heat source inlet of the second heat exchanger, and the cold source outlet of the second heat exchanger is connected to the hydrophobic tank.

[0017] Furthermore, in order to reduce the amount of equipment required, the steam outlet of the hydrophobic expansion tank is connected to the heat source inlet of the first heat exchanger.

[0018] Furthermore, in order to improve the system operating efficiency at the hydrophobic expansion vessel end, the steam outlet of the hydrophobic expansion vessel is connected to one end of the second exhaust steam pipeline, one end of the second pneumatic valve, and one end of the second shut-off valve; the other end of the second pneumatic valve and the other end of the second shut-off valve are connected to the second exhaust steam device.

[0019] Furthermore, to ensure the smooth transport of the medium, the second shut-off valve is a DN200 shut-off valve.

[0020] By adopting the above technical solution, this utility model can bring about beneficial effects:

[0021] This utility model is based on the heat energy recovery of the exhaust steam of the deaerator by the heat exchanger, which is used to heat the water in the deaerator, thereby increasing the water temperature in the deaerator and reducing the heat consumed per unit flow of water in the deaerator. When the flow demand is the same, the energy consumption is reduced, and when the flow demand increases, the equipment investment of the heat exchanger is reduced.

[0022] The heat recovery device of this utility model is also used to recover the steam heat of the hydrophobic expansion container, further improving the energy utilization rate;

[0023] The hydrophobic expansion container of this utility model can also recover heat based on the first heat exchanger, or it can recover heat based on a separate second heat exchanger. Based on this feature, the number of heat exchangers and their deployment locations can be specifically set according to the factory space and equipment input.

[0024] This utility model uses a combination of DN65, DN100, DN150 and DN200 pipes to ensure the normal operation of the entire waste steam recovery system with a smaller amount of equipment investment. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a system diagram of the deaerator end of a waste steam recovery device according to a specific embodiment of this utility model;

[0027] Figure 2 This is a system diagram of the water expansion tank end of a waste steam recovery device in a specific embodiment of this utility model;

[0028] The components are: 1. Deaerator; 2. First heat exchanger; 3. Drain tank; 4. First pneumatic valve; 5. First shut-off valve; 6. First exhaust device; 7. Drain expansion tank; 8. Second heat exchanger; 9. Second pneumatic valve; 10. Second shut-off valve; 11. Second exhaust device. Detailed Implementation

[0029] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0030] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0031] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0032] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this disclosure. The illustrations only show the components related to this disclosure and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0034] Definitions:

[0035] Deaerator 1: Removes dissolved oxygen (O2) and other non-condensable gases (such as CO2) from boiler feedwater, prevents oxygen corrosion of pipes and equipment, and preheats feedwater to improve thermal efficiency.

[0036] Flash Tank 7: Recovers flash steam from high-temperature and high-pressure condensate (such as boiler blowdown and steam pipe condensate) to avoid heat energy waste caused by direct discharge.

[0037] Flash evaporation principle: After high-pressure, high-temperature hydrophobic water enters the low-pressure container, due to the sudden drop in pressure, some of the water instantly vaporizes into low-pressure steam (secondary exhaust steam, one of the heat energy to be recovered in this embodiment).

[0038] Condensate: In thermal systems (such as power plants, boilers, and steam networks), condensate refers to the liquid water formed after high-temperature steam condenses in pipes or equipment, as well as excess water that needs to be discharged during system operation.

[0039] In one embodiment of this utility model, a waste steam recovery device is proposed, which recovers the heat energy of the waste steam from the deaerator 1 based on a heat exchange device, such as... Figure 1 As shown, the waste steam recovery unit includes:

[0040] Deaerator 1 is used to remove dissolved oxygen from demineralized water and generate high-temperature, high-pressure exhaust steam.

[0041] The first heat exchanger 2 has a heat source end inlet connected to high temperature and high pressure exhaust steam, a heat source end outlet connected to a condensate tank 3, a cold source end inlet connected to normal temperature demineralized water, and a cold source end outlet connected to the water inlet of the deaerator 1.

[0042] The outlet of the condensate tank 3 is connected to the inlet of the deaerator 1.

[0043] In this embodiment, the first heat exchanger 2 can be a waste steam heater. The first heat exchanger 2 recovers and reuses the waste steam from the deaerator 1 to preheat the low-temperature demineralized water entering the deaerator 1 (approximately 20°C before heating). After initially increasing its temperature, steam is then used to heat it to a deaeration temperature and pressure of 104–158°C and 0.02–0.6 MPa. This reduces the demand for high-temperature steam, saving steam and resulting in comprehensive savings in coal and electricity. It also plays a crucial role in optimizing the enterprise's water and heat balance. Furthermore, the energy-saving design reduces energy consumption, indirectly reducing the emission of soot, sulfides, and carbon dioxide into the atmosphere. It also significantly reduces exhaust noise, thus contributing to environmental protection. The overall social and economic benefits are also considerable.

[0044] In this embodiment, as Figure 1 As shown, in order to controllably allow the exhaust steam from deaerator 1 to enter the heat exchanger, the steam outlet of deaerator 1 is connected to one end of the first exhaust steam pipeline, one end of the first pneumatic valve 4, and one end of the first shut-off valve 5; the other end of the first pneumatic valve 4 and the other end of the first shut-off valve 5 are connected to the first exhaust steam device 6. In this embodiment, the first shut-off valve 5 is installed between deaerator 1 and the first exhaust steam device 6; when the first shut-off valve 5 is open, the exhaust steam is directly discharged through the first exhaust steam device 6; when closed, the first pneumatic valve 4 adjusts the flow rate of the high-temperature, high-pressure exhaust steam from deaerator 1 to the first exhaust steam device 6 based on the remote control opening size.

[0045] In this embodiment, as Figure 1 As shown, in order to control the flow direction of exhaust steam, the first shut-off valve 5 is a DN150 shut-off valve.

[0046] In this embodiment, as Figure 1 As shown, in order to ensure the normal operation of the first exhaust steam pipeline, the other end of the first exhaust steam pipeline is connected to the first heat exchanger 2; the first exhaust steam pipeline is a DN65 pipeline, and a DN100 shut-off valve, a DN100 check valve, a pressure gauge and a thermometer are installed on the pipeline.

[0047] In this embodiment, as Figure 1 As shown, in order to ensure the normal operation of the ambient temperature demineralized water pipeline, the ambient temperature demineralized water is transported to the first heat exchanger 2 through the DN65 ambient temperature demineralized water pipeline. The ambient temperature demineralized water pipeline is equipped with a DN65 shut-off valve, a DN65 pneumatic valve, a DN65 solenoid valve, a pressure gauge and a thermometer.

[0048] In this embodiment, as Figure 1 As shown, in order to ensure the flow rate of the medium, the first heat exchanger 2 and the condensate tank 3, as well as the condensate tank 3 and the deaerator 1, are connected by a normal temperature demineralized water pipeline; the diameter of the normal temperature demineralized water pipeline between the first heat exchanger 2 and the condensate tank 3 is DN65, and the diameter of the normal temperature demineralized water pipeline between the condensate tank 3 and the deaerator 1 is DN125.

[0049] In this embodiment, the parameters of the four deaerators 1 are the same, and the operating conditions and parameters are as follows:

[0050] Deaerator 1 exhaust pressure: 0.5 MPa; Deaerator 1 exhaust temperature: 158℃

[0051] Demineralized water temperature: 20℃; Outlet water temperature: 80℃ (tentative)

[0052] Deaerator 1 exhaust steam capacity: 1T / unit / H; Low-pressure feed water pressure: 0.7-0.8MPa

[0053] (2) Calculation of demineralized water usage:

[0054] The enthalpy of the exhaust steam at 158℃ is i0 = 2756.66 kJ / kg; the enthalpy of the demineralized water at 20℃ is i1 = 83.86 kJ / kg; the outlet temperature of the designed recovery unit is 80℃ and the enthalpy is i2 = 340.5 kJ / kg; the exhaust steam flow rate of each deaerator is m0 = 1 t / h.

[0055] Calculation of demineralized water usage for deaerator 1 exhaust steam recovery:

[0056] M1 = m0(i0-i2) / (i2-i1) = 14 t / h (single unit)

[0057] Therefore, the heater pipe diameter is selected as DN65, and the steam pipe diameter is selected as DN100.

[0058] (3) Exhaust steam recovery process:

[0059] Based on the above conditions and requirements, each deaerator 1 is recycled using a waste steam recovery device. After the waste steam is recovered, the condensate enters the existing condensate tank 3 and is then pumped back to the deaerator 1.

[0060] (4) Benefit analysis:

[0061] After the system upgrade, it can recover approximately 4 tons of secondary waste steam and condensate per hour. Based on an annual operating time of 8200 hours, the recovered heat, converted to standard coal equivalent, is approximately:

[0062] {4T / h×8200h×(2756.66kj / kg-1029.7kj / kg) / 4.18×7000} / 10-3≈1935T

[0063] Benefits: It can save 1,935 tons of standard coal, recover 32,800 tons of condensate water, and reduce carbon dioxide emissions by 5,031 tons per year.

[0064] In some embodiments, to further improve energy efficiency, the waste steam recovery device also includes a condensate expansion tank 7; the inlet of the condensate expansion tank 7 is connected to the boiler outlet.

[0065] In one embodiment, such as Figure 2 As shown, in order to improve energy efficiency, the steam outlet of the condensate expansion tank 7 is connected to the heat source inlet of the second heat exchanger 8, and the cold source outlet of the second heat exchanger 8 is connected to the condensate tank 3.

[0066] In this embodiment, to improve the system operating efficiency at the end of the condensate expansion container 7, the steam outlet of the condensate expansion container 7 is connected to one end of the second exhaust steam pipeline, one end of the second pneumatic valve 9, and one end of the second shut-off valve 10; the other end of the second pneumatic valve 9 and the other end of the second shut-off valve 10 are connected to the second exhaust steam device 11. In this embodiment, the second shut-off valve 10 is provided between the condensate expansion container 7 and the second exhaust steam device 11; when the second shut-off valve 10 is open, the exhaust steam is directly discharged through the second exhaust steam device 11; when closed, the second pneumatic valve 9 adjusts the flow rate of the secondary exhaust steam from the condensate expansion container 7 to the second exhaust steam device 11 based on the size of the remote control opening.

[0067] In this embodiment, in order to ensure the smooth transport of the medium, the second shut-off valve 10 is a DN200 shut-off valve.

[0068] In this embodiment, a separate second heat exchanger 8 is configured for the condensate drain container. While taking into account the plant space (the condensate expansion container 7 is generally located downstream of the boiler, while the deaerator 1 is located upstream of the boiler), this configuration can further improve energy efficiency. Similarly, in this embodiment, the condensate tank 3 can also be configured as a separate second condensate tank for the condensate expansion container 7.

[0069] In this embodiment, the three hydrophobic expansion tanks 7 have the same parameters, and the exhaust steam is used to heat the demineralized water and recover it to the deaerator 1.

[0070] (1) Operating conditions and parameters of hydrophobic expansion tank 7:

[0071] Hydrophobic expansion tank 7: Pressure: 0.1 MPa; Exhaust temperature: 109℃

[0072] Steam displacement: 1.5~2.0T / unit / H

[0073] (2) Calculation of demineralized water usage:

[0074] The enthalpy of the exhaust steam at 109℃ is i0 = 2690.22 kJ / kg; the enthalpy of the demineralized water at 20℃ is i1 = 83.86 kJ / kg; the designed outlet temperature of the recovery unit is 80℃ and the enthalpy is i2 = 340.5 kJ / kg; the constant exhaust steam flow rate per unit is m0 = 1.0 t / h.

[0075] Calculation of waste steam recovery demineralized water usage:

[0076] M1=m0(i0-i2) / (i2-i1)=9.2t / h

[0077] Therefore, the pipe diameter for the mixing heater is selected as DN65, and the steam pipe diameter is selected as DN100.

[0078] (3) Exhaust steam recovery process:

[0079] Solution: After the exhaust steam is recovered, the hot water first enters the vapor-liquid separator and then is sent back to deaerator 1 by a booster pump.

[0080] (4) Benefit analysis:

[0081] After the system upgrade, it can recover approximately 6 tons of secondary waste steam and condensate per hour. Based on 3600 hours of annual operation, the recovered heat, converted to standard coal equivalent, is approximately:

[0082] {6T / h×3600h×(2690.22kj / kg-1029.7kj / kg) / 4.18×7000} / 10-3≈1225.8T

[0083] Benefits: It can save 1,225.8 tons of standard coal, recover 21,600 tons of condensate water, and reduce carbon dioxide emissions by 3,187 tons per year.

[0084] In some embodiments, in order to reduce equipment investment, the steam outlet of the hydrophobic expansion container 7 is connected to the heat source inlet of the first heat exchanger 2.

[0085] This embodiment uses the same heat exchanger to recover steam heat from the deaerator 1 and the hydrophobic expansion tank 7, which can reduce the amount of equipment required.

[0086] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A steam recovery device, characterized by, The waste steam recovery device, which recovers the thermal energy of the deaerator based on heat exchange equipment, includes: A deaerator is used to remove dissolved oxygen from demineralized water and generate high-temperature, high-pressure exhaust steam. The first heat exchanger has a heat source inlet connected to the high-temperature and high-pressure exhaust steam, a heat source outlet connected to a condensate tank, and a cold source inlet connected to normal-temperature demineralized water, and a cold source outlet connected to the water inlet of the deaerator. Wherein: the outlet of the condensate tank is connected to the inlet of the deaerator.

2. The exhaust gas heat recovery device according to claim 1, characterized by The steam outlet of the deaerator is connected to one end of the first exhaust steam pipeline, one end of the first pneumatic valve, and one end of the first shut-off valve; the other end of the first pneumatic valve and the other end of the first shut-off valve are connected to the first exhaust steam device.

3. The exhaust gas heat recovery device according to claim 2, characterized by The first shut-off valve is a DN150 shut-off valve.

4. The exhaust gas heat recovery device according to claim 3, characterized by The other end of the first exhaust steam pipeline is connected to the first heat exchanger; the first exhaust steam pipeline is a DN65 pipeline, and a DN100 shut-off valve, a DN100 check valve, a pressure gauge and a thermometer are installed on the pipeline.

5. The exhaust gas heat recovery device according to claim 4, characterized by The ambient temperature demineralized water is transported to the first heat exchanger via a DN65 ambient temperature demineralized water pipeline. The ambient temperature demineralized water pipeline is equipped with a DN65 shut-off valve, a DN65 pneumatic valve, a DN65 solenoid valve, a pressure gauge, and a thermometer.

6. The exhaust heat recovery device according to claim 5, characterized by The first heat exchanger is connected to the condensate tank and the condensate tank is connected to the deaerator via a normal temperature demineralized water pipeline; the diameter of the normal temperature demineralized water pipeline between the first heat exchanger and the condensate tank is DN65, and the diameter of the normal temperature demineralized water pipeline between the condensate tank and the deaerator is DN125.

7. The exhaust heat recovery device according to claim 1, characterized by The waste steam recovery device also includes a condensate expansion tank; the inlet of the condensate expansion tank is connected to the boiler outlet water.

8. The waste steam recovery device according to claim 7, characterized in that, The steam outlet of the hydrophobic expansion tank is connected to the heat source inlet of the second heat exchanger, and the cold source outlet of the second heat exchanger is connected to the hydrophobic tank.

9. The exhaust heat recovery device according to claim 7, characterized by The steam outlet of the hydrophobic expansion vessel is connected to the heat source inlet of the first heat exchanger.

10. The exhaust gas heat recovery device according to claim 8 or 9, characterized by The steam outlet of the hydrophobic expansion tank is connected to one end of the second exhaust steam pipeline, one end of the second pneumatic valve, and one end of the second shut-off valve; the other end of the second pneumatic valve and the other end of the second shut-off valve are connected to the second exhaust steam device. The second shut-off valve is a DN200 shut-off valve.

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