Flue gas heat energy and condensate water utilization system

Abstract

The application discloses a flue gas heat energy and condensate water utilization system, which comprises a boiler, a flue gas cooling device, and a deoxygenated water tank. The flue gas generated by the boiler combustion enters the flue gas cooling device through a first flue for cooling. The flue gas exchanges heat with the water in the condensate water tank, the water in the condensate water tank is heated, the flue gas is cooled, and the cooled flue gas is discharged through a second flue. The condensate water formed in the flue gas cooling process falls into the condensate water tank. The water in the condensate water tank is deoxygenated by the deoxygenated water tank and then flows back to the boiler. The flue gas heat energy generated by the boiler combustion is utilized, the slightly acidic condensate water generated by the flue gas is mixed with the slightly alkaline softened water and the boiler water, the acidic condensate water and the alkaline softened water and the boiler water are subjected to acid-base neutralization reaction, the flue gas is used to heat the condensate water, and the like, so that the flue gas condensate water does not contain acidic gas, and thus the flue gas condensate water is slightly alkaline water suitable for the utilization of the boiler.

Description

Technical Field

[0001] This invention relates to the field of flue gas and thermal energy utilization technology, and more specifically, to a flue gas thermal energy and condensate utilization system. Background Technology

[0002] Currently, most boilers use natural gas as fuel. Since the main component of natural gas is methane, its combustion primarily produces carbon dioxide and water. This is especially true for gas-fired boilers, where the flue gas contains a significant amount of heat and water vapor. Although natural gas is relatively pure, small amounts of acidic gases may still be produced in the flue gas after combustion, dissolving in the condensate and making the condensate slightly acidic. Directly releasing this flue gas into the atmosphere leads to air pollution and also wastes the heat energy it contains. Furthermore, because the boiler softened water is alkaline, and the boiler water becomes even more alkaline due to continuous steam evaporation, the increasing alkalinity necessitates the continuous addition of new softened water, further increasing production costs.

[0003] Therefore, how to provide a flue gas heat energy and condensate utilization system to recover and utilize the flue gas and heat energy of boilers has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a flue gas heat energy and condensate utilization system for recovering and utilizing flue gas and heat energy from boilers.

[0005] This invention provides a flue gas heat energy and condensate utilization system, comprising: a boiler, the boiler being provided with a first flue; a flue gas cooling device, including a condensate tank and a second flue; and a deaerator tank; the flue gas generated by combustion in the boiler enters the flue gas cooling device through the first flue for cooling; the flue gas exchanges heat with the water in the condensate tank, the water in the condensate tank heats up, the flue gas cools down, and the cooled flue gas is discharged through the second flue; condensate is formed during the cooling process of the flue gas and falls into the condensate tank; the water in the condensate tank is deoxygenated by the deaerator tank and then flows back to the boiler.

[0006] Optionally, the flue gas cooling device further includes: an exchanger, with the second flue located at the top of the exchanger; a first horizontal flue, a second horizontal flue, a branch flue, and a third flue, wherein the first horizontal flue is connected to the first flue and located below the condensate tank, the second horizontal flue is located above the condensate tank, and multiple branch flues connect the first horizontal flue and the second horizontal flue, with the middle extension of the branch flues located inside the condensate tank; a third flue is provided above the second horizontal flue and connected thereto, extending into the lower part of the exchanger; a first main pipe, a second main pipe, and branch pipes, wherein the first main pipe and the second main pipe are arranged vertically and located on the horizontal sides of the exchanger respectively, and multiple branch pipes are sequentially connected vertically to the first main pipe and the second main pipe, with the middle extension of the branch pipes located inside the exchanger; the first main pipe can be connected to an external water source, and the second main pipe is connected to the condensate tank.

[0007] Optionally, the bottom of the heat exchanger is provided with a water collection tank, and the upper part of the water collection tank is provided with an overflow pipe, which is connected to the condensate tank.

[0008] Optionally, the outlet of the condensate tank is equipped with a pH meter, and the water in the condensate tank flows into the deaerator after being detected by the pH meter; the flue gas heat energy and condensate utilization system further includes: a blowdown expansion tank, into which the high-temperature boiler water can enter; when the pH meter detects that the pH value of the condensate tank outlet is acidic, the high-temperature boiler water is introduced into the blowdown expansion tank, and after the high-temperature boiler water expands and flashes in the blowdown expansion tank, its pH value increases and it can flow back to the condensate tank to neutralize the acidic water in the condensate tank.

[0009] Optionally, the flue gas heat energy and condensate utilization system further includes: a wastewater cooling tank and a heat exchanger; the heat exchanger is disposed between the first main pipe and the external water source; a gas collection chamber is provided at the upper part of the condensate tank, and the gas in the gas collection chamber exchanges heat with the incoming water from the first main pipe in the heat exchanger to form condensate and flow into the wastewater cooling tank.

[0010] Optionally, the high-temperature furnace water that has expanded and flashed in the sewage expansion tank can flow into the sewage cooling pool to neutralize the acid and alkali of the condensate of the gas in the gas collection chamber.

[0011] Optionally, the flue gas heat energy and condensate utilization system further includes: a steam distribution cylinder, which includes one steam inlet and two steam outlets; the steam generated by the boiler can enter the steam distribution cylinder through the steam inlet, and the steam in the steam distribution cylinder can enter the deaerator water tank through one of the steam outlets to heat the water in the deaerator water tank; a one-way valve is provided on the top of the blowdown expansion tank; the flash steam generated after the high-temperature boiler water expands and flashes through the blowdown expansion tank can be introduced into the deaerator water tank through the one-way valve to heat the water in the deaerator water tank.

[0012] Optionally, the flue gas heat energy and condensate utilization system further includes a chemical tank, which can add chemicals to the deoxygenated water tank to adjust the pH value inside the deoxygenated water tank.

[0013] Optionally, the flue gas heat energy and condensate utilization system further includes: water treatment equipment; the water in the sewage cooling pool can flow into the water treatment equipment for treatment and reuse.

[0014] Optionally, the flue gas heat energy and condensate utilization system further includes: a water collection tank, into which high-temperature furnace water in the sewage expansion tank flows; the water collection tank can supply water to the condensate tank and the sewage cooling pool respectively; and a level gauge is installed on the water collection tank.

[0015] According to the technical content disclosed in this invention, the following beneficial effects are achieved:

[0016] This invention utilizes the heat energy of flue gas generated by the combustion of clean natural gas in a boiler. Since the condensate produced by the flue gas is slightly acidic, alkaline softened water and boiler water are added to the condensate to allow the acidic condensate to undergo an acid-base neutralization reaction with the alkaline softened water and boiler water. The condensate is then heated by the flue gas to ensure that it does not contain acidic gases, thereby ensuring that the flue gas condensate is alkaline water suitable for boiler use. Finally, the condensate in the flue gas is recycled and reused.

[0017] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0019] Figure 1 This is a first part of a schematic diagram of a flue gas heat energy and condensate utilization system according to an embodiment;

[0020] Figure 2 This is the second part of a schematic diagram of a flue gas heat energy and condensate utilization system provided according to an embodiment. Detailed Implementation

[0021] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0022] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0023] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0024] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0026] This invention utilizes the heat energy of flue gas from a gas-fired boiler in two stages, while simultaneously making full use of the condensate. First, the boiler feedwater and flue gas heat energy exchange in a second-stage heat exchanger, lowering the flue gas temperature. The condensate produced in the flue gas then falls into the first-stage heat exchanger, i.e., the water tank. Although natural gas is relatively pure, a small amount of acidic gases may still be produced in the flue gas after combustion, dissolving in the condensate and resulting in a slightly acidic condensate. Since the boiler softened water is slightly alkaline, and the boiler water is further alkaline due to the continuous evaporation of steam, some softened water flows into the water tank after the second-stage heat exchanger to mix with the condensate. In some cases, a portion of the boiler water can even be mixed with the condensate, resulting in a neutral or slightly alkaline mixed condensate. Furthermore, the mixed condensate exchanges heat with the flue gas in the water tank, being heated to over 100 degrees Celsius. According to Dalton's law of partial pressures, various gases in the condensate evaporate, allowing the slightly alkaline condensate to enter the deaerator for boiler use. The gas and water vapor that evaporate from the condensate exchange heat with the boiler softened water again. The slightly acidic condensate is discharged into the outdoor cooling pool and mixed with the alkaline boiler wastewater to undergo a chemical reaction. The slightly neutral or alkaline mixed water then enters the water treatment equipment for further treatment.

[0027] See Figure 1 and Figure 2This invention provides a flue gas heat energy and condensate utilization system, comprising: a boiler 1, the boiler being provided with a first flue 2; a flue gas cooling device, including a condensate tank 10 and a second flue 26; and a deaerator tank 59; the flue gas generated by combustion in the boiler 1 enters the flue gas cooling device through the first flue 2 for cooling; the flue gas exchanges heat with the water in the condensate tank 10, the water in the condensate tank 10 heats up, the flue gas cools down, and the cooled flue gas is discharged through the second flue 26; condensate is formed during the cooling process of the flue gas and falls into the condensate tank 10; the water in the condensate tank 10 is deaerated by the deaerator tank 59 and then flows back to the boiler.

[0028] Furthermore, the flue gas cooling device further includes: an exchanger 22, with the second flue 26 located at the top of the exchanger 22; a first horizontal flue 6, a second horizontal flue 14, branch flues 8, and a third flue 104, wherein the first horizontal flue 6 communicates with the first flue 2 and is located below the condensate tank 10, the second horizontal flue 14 is located above the condensate tank 10, and a plurality of branch flues 8 connect the first horizontal flue 6 and the second horizontal flue 14, with the extended middle portion of each branch flue 8 located inside the condensate tank 10; the second horizontal flue 14... A third flue 104 is provided above and extends into the lower part of the heat exchanger 22; a first main pipe 29, a second main pipe 23, and branch pipes 27 are provided. The first main pipe 29 and the second main pipe 23 are arranged vertically and are located on the horizontal sides of the heat exchanger respectively. Multiple branch pipes 27 are connected vertically to the first main pipe 29 and the second main pipe 23 in sequence. The middle extension of the branch pipe 27 is located inside the heat exchanger 22; the first main pipe 29 can be connected to an external water source, and the second main pipe 23 is connected to the condensate tank 10.

[0029] Furthermore, the bottom of the exchanger 22 is provided with a water collection tank, and the upper part of the water collection tank is provided with an overflow pipe, which is connected to the condensate tank 10.

[0030] Furthermore, a pH meter 39 is installed at the outlet of the condensate tank 10. After the pH meter 39 detects the pH value of the water in the condensate tank 10, it flows into the deaerator tank 59. The flue gas heat energy and condensate utilization system also includes a blowdown expansion tank 97, into which the high-temperature boiler water of the boiler 1 can enter. When the pH meter 39 detects that the pH value of the water outlet of the condensate tank 10 is acidic, the high-temperature boiler water of the boiler 1 is introduced into the blowdown expansion tank 97. After the high-temperature boiler water expands and flashes in the blowdown expansion tank 97, its pH value increases and it can flow back to the condensate tank 10 to neutralize the acidic water in the condensate tank 10.

[0031] Furthermore, the flue gas heat energy and condensate utilization system also includes: a wastewater cooling tank 79 and a heat exchanger 48; the heat exchanger 48 is disposed between the first main pipe 29 and the external water source; a gas collection chamber 36 is provided on the upper part of the condensate tank 10, and the gas in the gas collection chamber 36 exchanges heat with the incoming water from the first main pipe 29 in the heat exchanger 48 to form condensate and flow into the wastewater cooling tank 79.

[0032] Furthermore, the high-temperature furnace water that has expanded and flashed in the sewage expansion tank 97 can flow into the sewage cooling pool 79 to neutralize the acid and alkali of the condensate of the gas in the gas collection chamber 36.

[0033] Furthermore, the flue gas heat energy and condensate utilization system also includes: a steam distribution cylinder 76, which includes one steam inlet and two steam outlets; the steam generated by the boiler 1 can enter the steam distribution cylinder 76 through the steam inlet, and the steam in the steam distribution cylinder 76 can enter the deaerator water tank 59 through one of the steam outlets to heat the water in the deaerator water tank 59; a one-way valve 94 is provided on the top of the blowdown expansion tank 97; the flash steam generated after the high-temperature boiler water expands and flashes through the blowdown expansion tank 97 can be introduced into the deaerator water tank 59 through the one-way valve 94 to heat the water in the deaerator water tank 59.

[0034] Furthermore, the flue gas heat energy and condensate utilization system also includes a chemical tank 57, which can add chemicals to the deoxygenated water tank 59 to adjust the pH value inside the deoxygenated water tank 59.

[0035] Furthermore, the flue gas heat energy and condensate utilization system also includes: a water treatment device 82; the water in the sewage cooling pool 79 can flow into the water treatment device 82 for treatment and reuse.

[0036] Furthermore, the flue gas heat energy and condensate utilization system also includes: a water collection tank 86, in which high-temperature furnace water in the sewage expansion tank 97 flows into the water collection tank 86; the water collection tank 86 can supply water to the condensate tank 10 and the sewage cooling pool 79 respectively; a second level gauge 87 is installed on the water collection tank 86.

[0037] Specifically, the boiler flue gas process is as follows: Boiler 1 uses clean energy natural gas as fuel. The flue gas generated by boiler 1 enters the first horizontal flue 6 of the first-stage flue gas exchanger through the first flue 2. The first horizontal flue 6 is connected to the branch flue 8 through multiple inlet first valves 7. The branch flue 8 is inside the condensate tank 10. The condensate tank 10 mainly contains condensate, while the branch flue 8 contains flue gas. After the flue gas and condensate exchange heat in the condensate tank 10, the flue gas, after initial cooling, enters the second horizontal flue 14 through the outlet second valve 13 of the branch flue 8. The flue gas in the second horizontal flue 14 enters the second-stage flue gas exchanger 22 through the third flue 104. The outlet of the third flue 104 is higher than the bottom of the exchanger 22 to prevent the condensate at the bottom of the exchanger 22 from flowing into the third flue 104 through the top. The heat exchanger 22, filled with flue gas, exchanges heat with the softened water in the branch pipe 27. The cooled flue gas, now with very low water vapor content, passes through the cone 25 and enters the second flue 26 before being discharged into the atmosphere. Alternatively, the first-stage and second-stage heat exchangers can be manufactured as a single product, requiring only the pre-installed connecting pipes and flue openings.

[0038] The process of generating, neutralizing, and utilizing flue gas condensate is as follows: Boiler softened water enters heat exchanger 48 through first pipe 50 and third valve 49, where it exchanges heat with the gas generated by flue gas condensate. The preheated boiler softened water flows out of heat exchanger 48. A portion of the boiler softened water enters the first main pipe 29 of exchanger 22 through fourth valve 47, twenty-ninth pipe 45, and first electric valve 30. There are many branch pipes 27 inside exchanger 22. Each branch pipe 27 has a fifth inlet valve 28 and a sixth outlet valve 24. Flue gas is outside the branch pipes 27 inside exchanger 22, and softened water is inside the branch pipes 27. The softened water in the first main pipe 29 enters each branch pipe 27 through the fifth inlet valve 28. After heat exchange between the softened water and flue gas in the exchanger 22 (the second-stage flue gas exchanger), the heated softened water flows out through the sixth outlet valve 24 into the second main pipe 23. The softened water in the second main pipe 23 then flows into the condensate tank 10 (the first-stage flue gas exchanger) through the second pipe 21 and the third pipe 17. As the flue gas and softened water exchange heat in the exchanger 22, the flue gas temperature decreases, and the steam in the flue gas condenses to produce condensate, which falls into the first collection tank 20 at the bottom of the exchanger. At the same time, a small amount of acidic gas may dissolve in the condensate. The first water collection tank 20 has two drainage devices on both sides of its bottom. Condensate in the first water collection tank 20 can be drained into the second water collection tank 16 via the first drain pipe 19, which extends into the bottom of the second water collection tank 16. The second water collection tank 16 has a first overflow pipe 18 at its upper part, through which the condensate overflows and drains into the condensate tank 10 via the first drain pipe 15. To prevent drainage problems with one drainage device, condensate in the first water collection tank 20 can also be drained into the third water collection tank 33 via the second drain pipe 31, which also extends into the bottom of the third water collection tank 33. The third water collection tank 33 has a second overflow pipe 32 at its upper part, through which the condensate overflows and drains into the condensate tank 10 via the second drain pipe 34. The above two drainage device designs allow water from the first water collection tank 20 at the bottom of the heat exchanger 22 to flow into the condensate tank 10, while steam from the condensate tank 10 cannot enter the heat exchanger 22 through the drainage device. Since the condensate tank 10 contains both slightly alkaline softened water and slightly acidic flue gas condensate, the condensate and softened water neutralize each other within the condensate tank 10. A first level gauge 37 is installed on the condensate tank 10. When the first level gauge 37 detects a high water level, the first electric valve 30 can reduce its opening, decreasing the amount of softened water entering the condensate tank 10. At this time, when the first pH meter 39 detects that the pH value of the condensate tank 10 outlet water is still slightly acidic, the high-temperature boiler water from the boiler 1 can enter the blowdown expansion tank 97 through the second electric valve 103 and the fourth pipe 102. The blowdown expansion tank 97 contains a baffle 96, which is connected to both the top and bottom of the blowdown expansion tank 97. The baffle 96 allows the flash-evaporated and lower-temperature boiler water to flow out preferentially.Therefore, after the high-temperature boiler water expands and flashes in the blowdown expansion tank 97, it flows through the bottom of the baffle 96 to the other side of the baffle. The overflow seventh valve 98 is installed in the upper part of the blowdown expansion tank 97. After the boiler water overflows from the blowdown expansion tank 97 through the seventh valve 98, it enters the water collection tank 86 through the fifth pipe 89 and the sixth pipe 88. The bottom of the blowdown expansion tank 97 is equipped with a first blowdown valve 99 and a first blowdown pipe 100. The water collection tank 86 is equipped with a second level gauge 87 to ensure that boiler drainage is always available in the water collection tank 86. The boiler water in the water collection tank 86 enters the first silencer 9 through the bottom seventh pipe 84, the first pump set 85, the eighth pipe 101, the ninth pipe 5, the third electric valve 12, and the thirtieth pipe 11. The boiler water is then released into the condensate tank 10 through the first silencer 9. Because a large amount of water evaporates from boiler 1, the boiler water has a relatively alkaline pH value. The condensate produced by gas combustion is not very acidic, so a suitable amount of boiler water can neutralize the acidity and alkali of the flue gas condensate. In this way, the flue gas condensate can be appropriately neutralized with softened water and boiler water, even adjusted to a slightly alkaline state for boiler use. A second drain valve 41 and a second drain pipe 42 are installed at the bottom of the condensate tank 10, which can be opened for periodic drainage. The neutral or slightly alkaline condensate in the condensate tank 10 flows out of the condensate tank 10, passes through the temperature sensor 38, the first pH meter 39, the second pump set 40, the tenth pipe 43, the eleventh pipe 60, and the fourth electric valve 62, and enters the deaerator head 64, thus falling into the deaerator tank 59 for boiler use. To prevent insufficient water level in the deaerator water tank 59, when the water level is low, the bypass fifth electric valve 54 opens. Softened water, after passing through the first pipe 50, the third valve 49, the heat exchanger 48, and the fourth valve 47, can then enter the eleventh pipe 60 via the twelfth pipe 53, the fifth electric valve 54, and the thirteenth pipe 55. Finally, it enters the deaerator head 64 via the fourth electric valve 62 and falls into the deaerator water tank 59, thus ensuring sufficient water volume. The mixture of condensate and softened water in the deaerator water tank 59, after being heated and deaerated, then flows through the third pump set 58, the twenty-first pipe 90, and the eighth valve 3 into the boiler 1 for boiler use. A second pH meter 63 is installed on the deoxygenated water tank. Even if the water in the deoxygenated water tank is slightly acidic, alkaline drugs can be delivered to the deoxygenated water tank 59 through the chemical tank 57 via the chemical pump 56 and the chemical pipe 61, ensuring that the water in the deoxygenated water tank 59 meets the alkaline requirements of boiler water.

[0039] Flash steam thermal energy utilization process: The condensate in the condensate tank 10 is heated by flue gas to above 100 degrees Celsius. According to Dalton's law of partial pressure, various gases in the condensate will overflow, thus ensuring that there is no oxygen, carbon dioxide, or other gases in the condensate. Therefore, the condensate in the condensate tank 10 is heated to above 100 degrees Celsius by flue gas. The various gases and water vapor overflowing from the condensate enter the gas collection chamber 36, and then enter the heat exchanger 48 through the 22nd pipe 35, the 23rd pipe 44, and the 9th valve 46 to exchange heat with the softened water. The condensate, which may be slightly acidic after condensation, flows out from the heat exchanger 48 and enters the wastewater cooling pool 79 through the 10th valve 51, the 24th pipe 52, the 14th pipe 68, and the 1st valve 77. Part of the wastewater from boiler 1 flows into the collection tank 86 via the blowdown expansion tank 97. Excess wastewater flows through the seventh pipe 84, the fifteenth pipe 83, and the sixth electric valve 78 into the blowdown cooling pool 79. In this way, the boiler water and acidic condensate undergo a neutralization reaction in the blowdown cooling pool 79. The slightly neutral or slightly alkaline water then flows through the fourth pump set 80 and the sixteenth pipe 81 into the water treatment equipment 82 for further treatment and reuse. The flash steam generated in the blowdown expansion tank 97 flows through the eleventh valve 95, the one-way valve 94, the seventeenth pipe 93, the eighteenth pipe 92, the nineteenth pipe 69, the twentieth pipe 67, and the seventh electric valve 66 into the second silencer 70, and then disperses into the water from the second silencer 70, thereby heating the condensate and softened water in the deaerated water tank 59. When the temperature inside the deaerator water tank 59 cannot reach 100 degrees Celsius, the steam generated by boiler 1 enters the steam distribution cylinder 76 via the twelfth valve 4, the twenty-fifth pipe 91, the twenty-sixth pipe 73, and the thirteenth valve 75. The steam in the steam distribution cylinder 76 also enters the nineteenth pipe 69 via the fourteenth valve 71 and the twenty-seventh pipe 105, and then enters the second silencer 70 via the nineteenth pipe 69, the twentieth pipe 67, and the seventh electric valve 66, thereby heating the water in the deaerator water tank 59. The gas overflowing from the deaerator water tank 59 exchanges heat with the inlet water through the deaerator head 64 and is discharged through the top vent pipe 65, thus ensuring that the water in the deaerator does not contain oxygen or other gases. The water in the deaerator water tank 59 is then used by boiler 1. The steam in the steam distribution cylinder 76 can also be used for production and domestic purposes via the fifteenth valve 74 and the twenty-eighth pipe 72.

[0040] In summary, this invention utilizes the heat energy of flue gas generated by the combustion of clean natural gas in a boiler. Since the condensate produced by the flue gas is slightly acidic, it incorporates slightly alkaline softened water and boiler water into the condensate. This allows the acidic condensate to undergo an acid-base neutralization reaction with the alkaline softened water and boiler water. Furthermore, the flue gas is used to heat the condensate to ensure that it does not contain acidic gases. This ensures that the flue gas condensate is alkaline enough for boiler use, ultimately allowing the condensate in the flue gas to be recycled.

[0041] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A flue gas heat energy and condensate utilization system, characterized in that, include: Boiler (1), wherein the boiler is provided with a first flue (2); The flue gas cooling device includes a condensate tank (10) and a second flue (26); Deoxygenated water tank (59); The flue gas generated by the combustion of the boiler (1) enters the flue gas cooling device through the first flue (2) for cooling; the flue gas exchanges heat with the water in the condensate tank (10), the water in the condensate tank (10) heats up, the flue gas cools down, and the cooled flue gas is discharged through the second flue (26); during the cooling process of the flue gas, condensate is formed and falls into the condensate tank (10); the water in the condensate tank (10) is deoxygenated by the deoxygenated water tank (59) and then flows back to the boiler; The flue gas cooling device further includes: The exchanger (22) has the second flue (26) located on top of the exchanger (22); The system comprises a first horizontal flue (6), a second horizontal flue (14), a branch flue (8), and a third flue (104). The first horizontal flue (6) is connected to the first flue (2) and is located below the condensate tank (10). The second horizontal flue (14) is located above the condensate tank (10). Multiple branch flues (8) are connected between the first horizontal flue (6) and the second horizontal flue (14). The middle extension of each branch flue (8) is located inside the condensate tank (10). A third flue (104) is provided above the second horizontal flue (14) and is connected to it. The third flue (104) extends into the lower part of the heat exchanger (22). A first main pipe (29), a second main pipe (23), and branch pipes (27) are arranged vertically and located on the horizontal sides of the exchanger, and multiple branch pipes (27) are connected vertically to the first main pipe (29) and the second main pipe (23) in sequence. The middle extension of the branch pipes (27) is located inside the exchanger (22). The first main pipe (29) can be connected to an external water source, and the second main pipe (23) is connected to the condensate tank (10).

2. The flue gas heat energy and condensate utilization system according to claim 1, characterized in that: The bottom of the exchanger (22) is provided with a water collection tank, and the upper part of the water collection tank is provided with an overflow pipe, which is connected to the condensate tank (10).

3. The flue gas heat energy and condensate utilization system according to claim 2, characterized in that: The outlet of the condensate tank (10) is equipped with a pH meter (39), and the water in the condensate tank (10) flows into the deoxygenated water tank (59) after being detected by the pH meter (39). The flue gas heat energy and condensate utilization system also includes: a blowdown expansion tank (97), and the high-temperature boiler water of the boiler (1) can enter the blowdown expansion tank (97). When the pH meter (39) detects that the pH value of the effluent from the condensate tank (10) is acidic, the high-temperature boiler water from the boiler (1) is introduced into the blowdown expansion tank (97). After the high-temperature boiler water expands and flashes in the blowdown expansion tank (97), its pH value increases and it can flow back to the condensate tank (10) to neutralize the acidic water in the condensate tank (10).

4. The flue gas heat energy and condensate utilization system according to claim 3, characterized in that... The flue gas heat energy and condensate utilization system also includes: Sewage cooling pool (79), heat exchanger (48); The heat exchanger (48) is disposed between the first main pipe (29) and the external water source; The upper part of the condensate tank (10) is provided with a gas collection chamber (36). The gas in the gas collection chamber (36) exchanges heat with the incoming water of the first main pipe (29) in the heat exchanger (48) to form condensate and flows into the sewage cooling pool (79).

5. The flue gas heat energy and condensate utilization system according to claim 4, characterized in that: The high-temperature boiler water that has expanded and flashed in the sewage expansion tank (97) can flow into the sewage cooling pool (79) to neutralize the acid and alkali of the condensate of the gas in the gas collection chamber (36).

6. The flue gas heat energy and condensate utilization system according to claim 4 or 5, characterized in that... The flue gas heat energy and condensate utilization system also includes: Steam distributor cylinder (76), the steam distributor cylinder (76) includes one steam inlet and two steam outlets; The steam generated by the boiler (1) can enter the steam distribution cylinder (76) through the steam inlet. The steam in the steam distribution cylinder (76) can enter the deaerator water tank (59) through one of the steam outlets to heat the water in the deaerator water tank (59). The top of the sewage expansion tank (97) is equipped with a one-way valve (94). The flash steam generated after the high-temperature boiler water expands and flashes through the sewage expansion tank (97) can be introduced into the deoxygenated water tank (59) through the one-way valve (94) to heat the water in the deoxygenated water tank (59).

7. The flue gas heat energy and condensate utilization system according to any one of claims 1 to 5, characterized in that... The flue gas heat energy and condensate utilization system also includes: The medicine box (57) can add medicine to the deoxygenated water tank (59) to adjust the pH value inside the deoxygenated water tank (59).

8. The flue gas heat energy and condensate utilization system according to claim 4 or 5, characterized in that... The flue gas heat energy and condensate utilization system also includes: Water treatment equipment (82); The water in the sewage cooling pool (79) can flow into the water treatment equipment (82) for treatment and reuse.

9. The flue gas heat energy and condensate utilization system according to claim 4 or 5, characterized in that... The flue gas heat energy and condensate utilization system also includes: The high-temperature furnace water in the sewage expansion tank (97) flows into the water collection tank (86); the water collection tank (86) can supply water to the condensate tank (10) and the sewage cooling pool (79) respectively; A second level gauge (87) is installed on the water collection tank (86).

Images