Waste heat recovery system for gas-fired boiler

Abstract

The invention discloses a waste heat recovery system for a gas-fired boiler, relates to the field of gas-fired boilers, and aims to solve the problems that in the prior art, water needs to be supplemented into the gas-fired boiler through an external water source due to circulating water loss during use of the gas-fired boiler, but the temperature of the external water source is low, water is directly supplemented into the gas-fired boiler, and the use cost of the gas-fired boiler is low. And hot water in the gas-fired boiler can be interfered. A heat exchange chamber is arranged in the gas-fired boiler body, a corrugated furnace pipe is fixedly arranged at the lower end in the heat exchange chamber, a smoke distribution box is fixedly connected to one side of the corrugated furnace pipe, and a plurality of first smoke heat exchange pipes are arranged in an array and fixedly connected between the upper end of one side of the smoke distribution box and the end face of one side of the heat exchange chamber. A plurality of second flue gas heat exchange pipes are arranged at the upper ends of the first flue gas heat exchange pipes in an array mode and fixedly connected between the end faces of the two sides in the heat exchange chamber, and a preheating water tank is fixedly connected to the end face of the other side of the gas-fired boiler body.

Description

Technical Field

[0001] The invention relates to the field of gas boilers, and in particular to a waste heat recovery system for gas boilers. Background Art

[0002] As the name suggests, a gas boiler refers to a boiler that uses gas as fuel. Gas boilers can be divided into natural gas boilers, city gas boilers, coke oven gas boilers, liquefied petroleum gas boilers and biogas boilers according to fuel; according to function, they can be divided into KS-Q gas-fired water boilers, CLHS / CWNS gas-fired hot water boilers (including gas-fired heating boilers and gas-fired bathing boilers), LHS / WNS gas-fired steam boilers, etc.; according to structure, they can be divided into vertical gas-fired boilers and horizontal gas-fired boilers; according to the flue gas process, they can be divided into single-pass gas-fired boilers and three-pass gas-fired boilers.

[0003] For example, the authorization announcement number, CN212657874U, discloses a gas boiler, including a boiler, a combustion chamber is arranged inside the lower part of the boiler, a filtering mechanism is installed on the upper left side of the boiler, and the lower right side of the exhaust pipe is connected to the combustion chamber. In this gas boiler, the filter plate can filter the particulate odor in the smoke to prevent air pollution, which solves the problem that the device does not filter the smoke generated during the combustion of gas, causing the smoke to pollute the air. The opening of the baffle is sealed above the vertical rod to control the flow of water. On the contrary, the water in the water inlet pipe of the baffle at the top of the vertical rod is discharged into the boiler through the opening on the baffle, realizing automatic water control, and having a wide range of uses, which solves the problem that the device cannot automatically control the external water from entering the boiler, resulting in a single range of uses.

[0004] Due to the loss of circulating water when using gas boilers, it is necessary to replenish water into the gas boiler through an external water source. However, the temperature of the external water source is relatively low, and directly replenishing it into the gas boiler will interfere with the hot water inside the gas boiler. Therefore, the market urgently needs to develop a waste heat recovery system for gas boilers to help people solve existing problems. Summary of the invention

[0005] The purpose of the present invention is to provide a waste heat recovery system for a gas boiler to solve the problem raised in the above background technology that due to the loss of circulating water when the gas boiler is in use, it is necessary to replenish water into the gas boiler through an external water source, but the temperature of the external water source is relatively low, and directly replenishing it into the gas boiler will interfere with the hot water inside the gas boiler.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a waste heat recovery system for a gas boiler, comprising a gas boiler main body, a heat exchange chamber is arranged inside the gas boiler main body, a corrugated furnace core is fixedly arranged at the lower end of the interior of the heat exchange chamber, a smoke separation box is fixedly connected to one side of the corrugated furnace core, a plurality of first flue gas heat exchange tubes are arranged in an array and fixedly connected between the upper end of one side of the smoke separation box and the end face of one side of the heat exchange chamber, a plurality of second flue gas heat exchange tubes are arranged in an array and fixedly connected at the upper ends of the plurality of first flue gas heat exchange tubes and between the end faces on both sides of the interior of the heat exchange chamber, a mixed gas preheating box is fixedly connected to the upper end of one end face of the gas boiler main body, a preheating water tank is fixedly connected to the other end face of the gas boiler main body, and a pressure relief box is fixedly connected to the middle part of the upper end of the gas boiler main body.

[0007] Preferably, a water inlet pipe is fixedly connected to one side of the upper end of the gas boiler body, and a water outlet pipe is fixedly connected to the lower end of one side of the front end of the gas boiler body.

[0008] Preferably, one side of the plurality of first flue gas heat exchange tubes and one side of the plurality of second flue gas heat exchange tubes are both connected to the interior of the mixed gas preheating box, and one side of the plurality of first flue gas heat exchange tubes and one side of the plurality of second flue gas heat exchange tubes are connected to the interior of the mixed gas preheating box through a U-shaped tube.

[0009] Preferably, a gas mixing device is connected to the upper end of one end surface of the mixed gas preheating box, one side of the gas mixing device is connected to the mixed gas preheating box through a gas supply pipe, the upper and lower ends of the gas mixing device are respectively fixedly connected to a gas pipe and an air pipe, and a first control valve is provided on the gas pipe and the air pipe, a burner is fixedly connected to the lower end of the mixed gas preheating box on one side of the gas boiler body, the output end of the burner is connected to the inside of the corrugated furnace, and the lower end of the mixed gas preheating box is connected to the burner through a delivery pipe.

[0010] Preferably, a rotating shaft is rotatably connected to the middle part of the gas mixing device, a plurality of stirring plates are fixedly connected to the rotating shaft, and a driving device is fixedly connected to the other end surface of the gas mixing device.

[0011] Preferably, a motor is fixedly arranged inside the driving device, and one end of the rotating shaft extends into the driving device and is fixedly connected to an output shaft of the motor.

[0012] Preferably, the other ends of the plurality of second flue gas heat exchange tubes are connected to the upper end of the interior of the preheating water tank, the lower end of one end surface of the preheating water tank is fixedly connected to a smoke collecting box, one side of the smoke collecting box is fixedly connected to a smoke exhaust pipe, and the plurality of second flue gas heat exchange tubes are connected between the interior of the preheating water tank and the smoke collecting box through an S-shaped tube.

[0013] Preferably, a water injection pipe is fixedly connected to the upper end of one end surface of the preheating water tank, a second control valve is fixedly connected to the water injection pipe, and a delivery pump is fixedly connected to the lower end of one end surface inside the preheating water tank.

[0014] Preferably, a delivery pipe is fixedly connected to one side of the delivery pump, and the delivery pipe passes through an end surface of one side of the preheating water tank and extends to the middle upper end of the interior of the gas boiler body.

[0015] Preferably, an air collecting chamber is provided inside the pressure relief box, the lower end of the air collecting chamber is connected to the interior of the gas boiler body, an air pressure monitor is fixedly connected to one side of the upper end surface of the air collecting chamber, an exhaust pipe is fixedly connected to the middle part of the upper end of the pressure relief box, and a third control valve is provided on the exhaust pipe.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. In the present invention, by providing a preheating water tank, an S-shaped pipe and a delivery pump, it is achieved that the preheating water inside the preheating water tank is preheated in advance by means of flue gas preheating, so that the preheating water has a certain temperature when entering the heat exchange chamber, and the low temperature of the preheating water is prevented from causing a large interference to the temperature of the hot water inside the heat exchange chamber. At the same time, the preheating water is delivered to the middle upper end of the heat exchange chamber by the delivery pump, so that the preheating water and the hot water are fully mixed inside the heat exchange chamber, and at the same time, they are kept away from the water outlet pipe, so as to prevent the preheating water from being discharged through the water outlet pipe without being fully heated, thereby ensuring the heating effect of the circulating water.

[0018] 2. In the present invention, multiple first flue gas heat exchange tubes, multiple second flue gas heat exchange tubes and mixed gas preheating boxes are provided, which realize the effective preheating of the mixed gas by using the high-temperature flue gas, thereby improving the combustion efficiency. The temperature of the high-temperature flue gas gradually decreases after flowing through the multiple first flue gas heat exchange tubes, multiple U-shaped tubes and multiple second flue gas heat exchange tubes, and the multiple second flue gas heat exchange tubes are used to reflow into the heat exchange chamber, and the multiple second flue gas heat exchange tubes are used to heat the circulating water again, thereby realizing the sufficient heating of the circulating water inside the heat exchange chamber, thereby effectively improving the heat utilization rate.

[0019] 3. In the invention, by setting up a pressure relief box, an air collecting chamber, an air pressure monitor and an exhaust pipe, the steam is collected uniformly by using the air collecting chamber to be separated from the hot water for heating, so as to prevent the steam from driving the circulating water to spray out from the exhaust pipe due to excessive air pressure during exhaust, thus causing danger. The air pressure is monitored in real time by the air pressure monitor, and when the air pressure is too high, it is discharged through the exhaust pipe, thus ensuring the safe operation of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view of a waste heat recovery system for a gas boiler according to the present invention;

[0021] Figure 2is a main cross-sectional view of the present invention;

[0022] Figure 3 is a side sectional view of the present invention;

[0023] Figure 4 It is an enlarged view of the detail A of the present invention;

[0024] Figure 5 It is an enlarged view of detail B of the present invention.

[0025] In the figure: 1. gas boiler body; 101. heat exchange chamber; 102. water inlet pipe; 103. water outlet pipe; 2. corrugated furnace; 201. smoke distribution box; 202. burner; 3. first flue gas heat exchange pipe; 301. second flue gas heat exchange pipe; 4. mixed gas preheating box; 401. U-shaped pipe; 402. conveying pipe; 5. gas mixing device; 501. rotating shaft; 502. stirring plate; 503. driving device; 504. electric machine; 505, gas pipe; 506, air pipe; 507, first control valve; 508, gas supply pipe; 6, preheating water tank; 601, smoke collecting box; 602, smoke exhaust pipe; 603, S-shaped pipe; 604, water injection pipe; 605, second control valve; 606, delivery pump; 607, delivery pipe; 7, pressure relief box; 701, gas collecting chamber; 702, air pressure monitor; 703, exhaust pipe; 704, third control valve. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] See also Figure 1-5 An embodiment of the present invention is as follows: a waste heat recovery system for a gas boiler, comprising a gas boiler body 1, a heat exchange chamber 101 is arranged inside the gas boiler body 1, a water inlet pipe 102 is fixedly connected to one side of the upper end of the gas boiler body 1, a water outlet pipe 103 is fixedly connected to the lower end of one side of the front end of the gas boiler body 1, an external circulating water return pipe is connected through the water inlet pipe 102, so that the external circulating water enters the heat exchange chamber 101 inside the gas boiler body 1 through the water inlet pipe 102 for heating, and the heated circulating water flows out through the water outlet pipe 103,

[0028] See also Figure 2-3A corrugated furnace 2 is fixedly arranged at the lower end of the heat exchange chamber 101, and a smoke separation box 201 is fixedly connected to one side of the corrugated furnace 2. A plurality of first flue gas heat exchange tubes 3 are arranged in an array and fixedly connected between the upper end of one side of the smoke separation box 201 and the end face of one side of the heat exchange chamber 101. A plurality of second flue gas heat exchange tubes 301 are arranged in an array and fixedly connected between the upper ends of the plurality of first flue gas heat exchange tubes 3 and the end faces on both sides of the heat exchange chamber 101. A mixed gas preheating box 4 is fixedly connected to the upper end of the end face of one side of the gas boiler body 1. A gas preheating box 4 is fixedly connected to the lower end of the mixed gas preheating box 4 on one side of the gas boiler body 1. A burner 202 is fixedly connected, and the output end of the burner 202 is connected to the inside of the corrugated furnace 2. The burner 202 is ignited and burned inside the corrugated furnace 2, so that the corrugated furnace 2 is heated to heat the circulating water inside the heat exchange chamber 101. At the same time, the high-temperature flue gas generated by the combustion flows to one side into the smoke separation box 201, and the high-temperature flue gas is diverted to multiple first flue gas heat exchange tubes 3 through the smoke separation box 201. When the high-temperature flue gas flows through the first flue gas heat exchange tube 3, it heats the first flue gas heat exchange tube 3, so that the first flue gas heat exchange tube 3 continues to heat the circulating water.

[0029] See also Figure 2 and Figure 4 , one side of the plurality of first flue gas heat exchange tubes 3 and one side of the plurality of second flue gas heat exchange tubes 301 are both connected to the interior of the mixed gas preheating box 4, and one side of the plurality of first flue gas heat exchange tubes 3 and one side of the plurality of second flue gas heat exchange tubes 301 are connected to the interior of the mixed gas preheating box 4 through the U-shaped tube 401, and the high-temperature flue gas inside the first flue gas heat exchange tube 3 is guided inside the mixed gas preheating box 4 through the plurality of U-shaped tubes 401 and flows into the plurality of second flue gas heat exchange tubes 301, and the plurality of U-shaped tubes 401 are heated when the high-temperature flue gas flows in the U-shaped tubes 401, so that the mixed gas of the external air and the fuel gas is preheated when passing through the interior of the mixed gas preheating box 4, and the mixed gas The lower end of the gas preheating box 4 is connected to the burner 202 through a delivery pipe 402, so that the mixed gas of air and fuel gas has a certain temperature when entering the burner 202 for combustion, thereby realizing effective preheating of the mixed gas by using high-temperature flue gas and improving the combustion efficiency. The high-temperature flue gas flows back to the inside of the heat exchange chamber 101 through multiple second flue gas heat exchange pipes 301, and the circulating water is heated again by the multiple second flue gas heat exchange pipes 301 to fully heat the circulating water in the heat exchange chamber 101. The temperature of the high-temperature flue gas gradually decreases after flowing through multiple first flue gas heat exchange pipes 3, multiple U-shaped pipes 401 and multiple second flue gas heat exchange pipes 301.

[0030] See also Figure 2 and Figure 4The upper end of one side end surface of the mixed gas preheating box 4 is connected to a mixing device 5, one side of the mixing device 5 is connected to the mixed gas preheating box 4 through an air supply pipe 508, the upper and lower ends of the mixing device 5 are respectively fixedly connected to a gas pipe 505 and an air pipe 506, and the gas pipe 505 and the air pipe 506 are both provided with a first control valve 507, the middle part of the mixing device 5 is rotatably connected to a rotating shaft 501, and a plurality of stirring plates 502 are fixedly connected to the rotating shaft 501, and a driving device 503 is fixedly connected to the other side end surface of the mixing device 5, and the driving device 503 is fixed inside A motor 504 is provided, one end of the rotating shaft 501 extends to the interior of the driving device 503 and is fixedly connected to the output shaft of the motor 504. The first control valve 507 is opened, so that the gas pipe 505 and the air pipe 506 simultaneously inject a certain proportion of gas and air into the mixed gas preheating box 4. The rotating shaft 501 is driven by the motor 504 to rotate, so that the rotating shaft 501 drives multiple stirring plates 502 to stir the gas and air, so that the gas and air are fully mixed, and the mixed gas of the gas and air is sent into the interior of the mixed gas preheating box 4 through the gas supply pipe 508 under the action of air pressure.

[0031] See also Figure 2 The other end surface of the gas boiler body 1 is fixedly connected to a preheating water tank 6, and an injection pipe 604 is fixedly connected to the upper end of one end surface of the preheating water tank 6. A second control valve 605 is fixedly connected to the injection pipe 604. The second control valve 605 is opened to fill the preheating water tank 6 with preheating water through the injection pipe 604. The other ends of the plurality of second flue gas heat exchange pipes 301 are connected to the upper end of the preheating water tank 6. The lower end of the end surface of one side of the preheating water tank 6 is fixedly connected to a smoke collecting box 601, and one side of the smoke collecting box 601 is fixedly connected to a smoke exhaust pipe 602. The plurality of second flue gas heat exchange pipes 301 are connected between the inside of the preheating water tank 6 and the smoke collecting box 601 through an S-shaped pipe 603. After the smoke flows out of the plurality of second flue gas heat exchange pipes 301, it is sent into the smoke collecting box 600 through the plurality of S-shaped pipes 603 and is discharged from the smoke exhaust pipe 602 is discharged, and the preheated water in the preheating water tank 6 is preheated by flue gas preheating, so that the preheated water has a certain temperature when entering the heat exchange chamber 101, so as to prevent the low temperature of the preheated water from causing great interference to the temperature of the hot water in the heat exchange chamber 101. A delivery pump 606 is fixedly connected to the lower end of the end surface on one side of the preheating water tank 6, and a delivery pipe 607 is fixedly connected to one side of the delivery pump 606. The delivery pipe 607 passes through the end surface on one side of the preheating water tank 6 and extends to the middle upper end of the heat exchange chamber 101 inside the gas boiler body 1. The preheated water is delivered to the middle upper end of the heat exchange chamber 101 by the delivery pump 606, so that the preheated water and the hot water are fully mixed in the heat exchange chamber 101, and at the same time, they are kept away from the outlet pipe 103, so as to prevent the preheated water from being discharged through the outlet pipe 103 without being fully heated.

[0032] See also Figure 2 and Figure 5A pressure relief box 7 is fixedly connected to the middle of the upper end of the gas boiler body 1, and an air collecting chamber 701 is arranged inside the pressure relief box 7. The lower end of the air collecting chamber 701 is connected to the inside of the gas boiler body 1. A pressure monitor 702 is fixedly connected to one side of the upper end surface of the air collecting chamber 701. An exhaust pipe 703 is fixedly connected to the middle of the upper end of the pressure relief box 7. A third control valve 704 is arranged on the exhaust pipe 703. The principle of gas rising in water is utilized to make the steam inside the heat exchange chamber 101 rise and enter the air collecting chamber 701 for collection. The air pressure is monitored in real time by the air pressure monitor 702. When the air pressure is too high, it is discharged through the exhaust pipe 703 through the third control valve 704. The steam is uniformly collected through the air collecting chamber 701 to be separated from the hot water exchange water, so as to prevent the steam from driving the circulating water to spray out from the exhaust pipe 703 due to excessive air pressure during exhaust, thereby causing danger.

[0033] Working principle: When in use, the external circulating water return pipe is connected through the water inlet pipe 102, so that the external circulating water enters the heat exchange chamber 101 inside the gas boiler body 1 through the water inlet pipe 102 for heating, and the heated circulating water flows out through the water outlet pipe 103, and the burner 202 is ignited and burns inside the corrugated furnace 2, so that the corrugated furnace 2 is heated to heat the circulating water inside the heat exchange chamber 101, and at the same time, the high-temperature flue gas generated by the combustion flows to one side and enters the inside of the smoke separation box 201, and the high-temperature flue gas is diverted to multiple first flue gas heat exchange tubes 3 through the smoke separation box 201. When the high-temperature flue gas flows through the first flue gas heat exchange tube 3, it heats the first flue gas heat exchange tube 3, so that the first flue gas heat exchange tube 3 continues to heat the circulating water, and the high-temperature flue gas inside the first flue gas heat exchange tube 3 passes through multiple The U-shaped tube 401 guides the gas mixture preheating box 4 and flows into the multiple second flue gas heat exchange tubes 301. The first control valve 507 is opened to allow the gas pipe 505 and the air pipe 506 to simultaneously inject a certain proportion of gas and air into the gas mixture preheating box 4. The motor 504 drives the rotating shaft 501 to rotate, so that the rotating shaft 501 drives the multiple stirring plates 502 to stir the gas and air, so that the gas and air are fully mixed. The gas mixture of gas and air is sent into the gas mixture preheating box 4 through the gas supply pipe 508 under the action of air pressure. When the high-temperature flue gas flows in the U-shaped tube 401, the multiple U-shaped tubes 401 are heated, so that the mixed gas of external air and gas is preheated when passing through the mixed gas preheating box 4. The lower end of the heat box 4 is connected to the burner 202 through a delivery pipe 402, so that the mixed gas of air and fuel gas has a certain temperature when entering the burner 202 for combustion, and the high-temperature flue gas is used to effectively preheat the mixed gas, thereby improving the combustion efficiency. The high-temperature flue gas flows back to the inside of the heat exchange chamber 101 through the multiple second flue gas heat exchange pipes 301, and the circulating water is heated again by the multiple second flue gas heat exchange pipes 301 to fully heat the circulating water in the heat exchange chamber 101. After the high-temperature flue gas flows through the multiple first flue gas heat exchange pipes 3, the multiple U-shaped pipes 401 and the multiple second flue gas heat exchange pipes 301, the temperature of the high-temperature flue gas gradually decreases, the second control valve 605 is opened, and the preheating water tank 6 is filled with preheated water through the water injection pipe 604. The other end of the heat pipe 301 is connected to the upper end of the preheating water tank 6. The plurality of second flue gas heat exchange pipes 301 are connected to the smoke collecting box 601 through the S-shaped pipe 603. After the flue gas flows out from the plurality of second flue gas heat exchange pipes 301, it is sent into the smoke collecting box 601 through the plurality of S-shaped pipes 603 and discharged from the smoke exhaust pipe 602. The preheated water in the preheating water tank 6 is preheated by the flue gas preheating, so that the preheated water has a certain temperature when entering the heat exchange chamber 101, so as to prevent the low temperature of the preheated water from causing a greater interference to the temperature of the heat exchange water in the heat exchange chamber 101. The preheated water is sent to the middle upper end of the heat exchange chamber 101 through the delivery pump 606, so that the preheated water and the heat exchange water are fully mixed in the heat exchange chamber 101, and at the same time, away from the outlet pipe 103.To prevent the preheated water from being discharged through the outlet pipe 103 before being fully heated, the principle of gas rising in water is used to make the steam inside the heat exchange chamber 101 rise and enter the gas collecting chamber 701 for collection. The air pressure is monitored in real time through the air pressure monitor 702. When the air pressure is too high, it is discharged through the exhaust pipe 703 through the third control valve 704. The steam is uniformly collected through the gas collecting chamber 701 to achieve separation from the hot water, to prevent the steam from driving the circulating water to spray out from the exhaust pipe 703 due to excessive air pressure during exhaust, causing danger.

[0034] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A waste heat recovery system for a gas boiler, comprising a gas boiler body (1), characterized in that: A heat exchange chamber (101) is arranged inside the gas boiler body (1), a corrugated furnace (2) is fixedly arranged at the lower end of the heat exchange chamber (101), a smoke separation box (201) is fixedly connected to one side of the corrugated furnace (2), a plurality of first flue gas heat exchange tubes (3) are arranged in an array and fixedly connected between the upper end of one side of the smoke separation box (201) and the end face of one side of the heat exchange chamber (101), a plurality of second flue gas heat exchange tubes (301) are arranged in an array and fixedly connected at the upper ends of the plurality of first flue gas heat exchange tubes (3) and between the end faces on both sides of the heat exchange chamber (101), a mixed gas preheating box (4) is fixedly connected to the upper end of one side of the gas boiler body (1), a preheating water tank (6) is fixedly connected to the other side of the gas boiler body (1), and a pressure relief box (7) is fixedly connected to the middle part of the upper end of the gas boiler body (1).

2. The waste heat recovery system for a gas boiler according to claim 1, characterized in that: A water inlet pipe (102) is fixedly connected to one side of the upper end of the gas boiler body (1), and a water outlet pipe (103) is fixedly connected to the lower end of one side of the front end of the gas boiler body (1).

3. The waste heat recovery system for a gas boiler according to claim 1, characterized in that: One side of the plurality of first flue gas heat exchange tubes (3) and one side of the plurality of second flue gas heat exchange tubes (301) are both connected to the interior of the mixed gas preheating box (4); one side of the plurality of first flue gas heat exchange tubes (3) and one side of the plurality of second flue gas heat exchange tubes (301) are connected inside the mixed gas preheating box (4) via a U-shaped tube (401).

4. The waste heat recovery system for a gas boiler according to claim 1, characterized in that: The upper end of one end surface of the mixed gas preheating box (4) is connected to a gas mixing device (5), one side of the gas mixing device (5) is connected to the mixed gas preheating box (4) via a gas supply pipe (508), the upper and lower ends of the gas mixing device (5) are respectively fixedly connected to a gas pipe (505) and an air pipe (506), and both the gas pipe (505) and the air pipe (506) are provided with a first control valve (507), one side of the gas boiler body (1) is fixedly connected to a burner (202) at the lower end of the mixed gas preheating box (4), the output end of the burner (202) is communicated with the inside of the corrugated furnace (2), and the lower end of the mixed gas preheating box (4) is connected to the burner (202) via a delivery pipe (402).

5. The waste heat recovery system for a gas boiler according to claim 4, characterized in that: A rotating shaft (501) is rotatably connected to the middle part of the gas mixing device (5), a plurality of stirring plates (502) are fixedly connected to the rotating shaft (501), and a driving device (503) is fixedly connected to the other end surface of the gas mixing device (5).

6. A waste heat recovery system for a gas boiler according to claim 5, characterized in that: A motor (504) is fixedly arranged inside the driving device (503), and one end of the rotating shaft (501) extends into the driving device (503) and is fixedly connected to the output shaft of the motor (504).

7. The waste heat recovery system for a gas boiler according to claim 1, characterized in that: The other ends of the plurality of second flue gas heat exchange tubes (301) are connected to the upper end of the interior of the preheating water tank (6); a smoke collecting box (601) is fixedly connected to the lower end of one end surface of the preheating water tank (6); a smoke collecting box (601) is fixedly connected to one side of the smoke collecting box (601); and a smoke exhaust pipe (602) is fixedly connected to the interior of the preheating water tank (6) and the smoke collecting box (601) via an S-shaped tube (603).

8. The waste heat recovery system for a gas boiler according to claim 7, characterized in that: A water injection pipe (604) is fixedly connected to the upper end of one end surface of the preheating water tank (6), a second control valve (605) is fixedly connected to the water injection pipe (604), and a delivery pump (606) is fixedly connected to the lower end of one end surface inside the preheating water tank (6).

9. The waste heat recovery system for a gas boiler according to claim 8, characterized in that: A delivery pipe (607) is fixedly connected to one side of the delivery pump (606), and the delivery pipe (607) passes through an end surface of one side of the preheating water tank (6) and extends to the middle upper end of the interior of the gas boiler body (1).

10. The waste heat recovery system for a gas boiler according to claim 1, characterized in that: The pressure relief box (7) is provided with an air collecting chamber (701) inside, the lower end of the air collecting chamber (701) is connected to the inside of the gas boiler body (1), a pressure monitor (702) is fixedly connected to one side of the upper end surface of the air collecting chamber (701), an exhaust pipe (703) is fixedly connected to the middle part of the upper end of the pressure relief box (7), and a third control valve (704) is provided on the exhaust pipe (703).

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