Waste heat utilization flue supplementary combustion device and supplementary combustion method thereof

Abstract

The present invention discloses a flue supplementary combustion device for waste heat utilization and a supplementary combustion method thereof, belonging to the technical field of waste heat utilization, comprising: an intake pipe, wherein a combustion engine air inlet and a fresh air inlet are respectively provided on the intake pipe, and a fresh air regulating valve is installed inside the fresh air inlet; a heating frame, wherein one end of the heating frame is communicated with the intake pipe, and a flow equalizing plate, a supplementary burner and a heating pipe are sequentially installed inside the heating frame along a direction away from the intake pipe; a main chimney, wherein the main chimney is located at an end of the heating frame away from the intake pipe, and the main chimney is communicated with the heating frame through a connecting pipe and an exhaust pipe respectively, a first electric valve is installed inside the connecting pipe, and a fan and a second electric valve are installed inside the exhaust pipe. The present invention can heat the waste heat boiler when the gas turbine is shut down without the need for a spare gas boiler.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat utilization, and in particular to a waste heat utilization flue supplementary combustion device and a supplementary combustion method thereof. Background Art

[0002] In the application fields of gas power plants and natural gas distributed energy stations, gas turbine waste heat boilers with flue re-firing devices are increasingly being used by customers. Their wide load adaptability and peak-shaving capabilities can meet customers' diverse heat and electricity needs.

[0003] Conventional flue-fired gas turbine waste heat boiler systems utilize the residual oxygen (approximately 15% by volume) in the flue gas discharged from the gas turbine to connect the fuel (usually natural gas) to a dedicated flue afterburner for combustion. This increases the temperature of the gas turbine exhaust gas without providing combustion-supporting air, thereby heating the waste heat boiler.

[0004] However, when the gas turbine is shut down for reasons such as failure, overhaul, or maintenance, conventional flue-fired gas turbine waste heat boilers cannot function properly due to the afterburner and waste heat boiler system, forcing them to shut down. Therefore, many users, after configuring conventional afterburned gas turbine waste heat boilers, must also install additional backup gas boilers as a backup heat source when the gas turbine is shut down in order to meet the uninterrupted heating needs of heat users. This increases the customer's investment and operating costs, especially due to factors such as the large footprint of gas boilers, the large number of auxiliary machines, the high operating power consumption, and the high failure rate, which increase the user's heating costs. The present invention provides a flue-fired waste heat utilization device and a method for the afterburning. Summary of the Invention

[0005] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a waste heat utilization flue re-combustion device and re-combustion method, which can heat the waste heat boiler when the gas turbine is shut down without the need for a spare gas boiler.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: The present invention provides a flue gas post-combustion device for utilizing waste heat, comprising:

[0007] An air intake pipe, wherein the air intake pipe is provided with a combustion engine air intake and a fresh air intake, and a fresh air regulating valve is installed inside the fresh air intake;

[0008] A heating frame, one end of which is in communication with the air inlet pipe, wherein a flow equalizer, an afterburner, and a heating pipe are sequentially installed inside the heating frame in a direction away from the air inlet pipe;

[0009] The main chimney is located at one end of the heating frame away from the air inlet pipe, and the main chimney is connected to the heating frame through a connecting pipe and an exhaust pipe respectively. A first electric valve is installed inside the connecting pipe, and a fan and a second electric valve are installed inside the exhaust pipe.

[0010] Preferably, the interior of the heating pipe is fixedly connected with multiple groups of heat-conducting components, and the heat-conducting components include multiple heat-conducting plates. The material of the heat-conducting plates is an elastic material with high thermal conductivity, and one end of the heat-conducting plate is a fixed end fixedly connected to the inner wall of the heating pipe, and the other end is a floating end, which is deflected toward the direction of the axis of the heating pipe.

[0011] Preferably, the heat conducting sheet is wavy in shape.

[0012] Preferably, the multiple heat conducting plates in two adjacent heat conducting components are staggeredly distributed.

[0013] Preferably, the heating pipe is connected to a switching valve installed on the upper side of the heating frame, and the flow direction of water in the heating pipe is adjusted by starting the switching valve.

[0014] Preferably, the switching valve comprises:

[0015] A valve frame, wherein the valve frame is fixed on the heating frame, and an inlet pipe and an outlet pipe are fixedly connected to the annular surface of the valve frame;

[0016] A valve core is rotatably mounted inside the valve frame and driven by a motor mounted on the valve frame;

[0017] Wherein, both ends of the heating pipe are connected to the interior of the valve frame, the inlet pipe and the outlet pipe are symmetrical with respect to the axis of the valve frame, and both ends of the heating pipe are also symmetrical with respect to the axis of the valve frame.

[0018] Preferably, the heating pipes are distributed in a rectangular spiral inside the heating frame.

[0019] A supplementary combustion method for the flue supplementary combustion device as described above is characterized by comprising:

[0020] Step 1: Close the first electric valve to isolate the connecting pipe from the interior of the heating frame;

[0021] Step 2: Open the fresh air regulating valve and the second electric valve, open the fresh air inlet, and connect the exhaust pipe to the heating frame;

[0022] Step 3: Start the fan to allow the outside air to enter the interior of the heating frame through the fresh air inlet and the air inlet pipe;

[0023] Step 4: Start the afterburner to heat the heating pipe;

[0024] Step 5: Start the motor every 10 days to allow the motor to drive the valve core to rotate 90 degrees.

[0025] The beneficial effects of the present invention are:

[0026] The present invention realizes that when the gas turbine is shut down, the fresh air regulating valve and the second electric valve can be opened by setting the fresh air inlet and the fan, so that the outside air can enter the interior of the heating frame, and oxygen is added to the interior of the heating frame for combustion by the afterburner to heat the heating pipe.

[0027] The present invention increases the heated area of ​​the water flowing inside the heating pipe by setting the heat conductive sheet, can quickly transfer heat from the pipe wall to the water flow, reduces the temperature unevenness inside the heating pipe, and thus improves the uniformity of heating. At the same time, the heat conductive sheet can destroy the laminar boundary layer formed by the water flow around the pipe wall, and promote the transfer of heat from the pipe wall to the inside of the water flow.

[0028] The present invention realizes the ability to adjust the flow direction of water inside the heating pipe through the setting of the switching valve. At this time, the direction of the floating end of the heat conducting plate will change accordingly with the flow direction of water, thereby avoiding the formation of scale on the inner wall of the heating pipe and the heat conducting plate, which affects the heating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0031] Figure 2 It is a cross-sectional view of the present invention.

[0032] Figure 3 Schematic diagram of the internal structure of the valve frame of the present invention.

[0033] Figure 4 It is a schematic diagram of the overall structure of the heating pipeline of the present invention.

[0034] Figure 5 This is a schematic diagram of the internal structure of the heating pipe of the present invention.

[0035] Figure 6 It is a cross-sectional view of the heating pipe of the present invention.

[0036] Figure 7 Schematic diagram of the structure of the heat conducting sheet of the present invention.

[0037] Description of reference numerals:

[0038] 1. Inlet pipe, 2. Gas turbine air inlet, 3. Fresh air inlet, 4. Fresh air regulating valve, 5. Heating frame, 6. Flow equalizing plate, 7. Afterburner, 8. Heating pipe, 9. Main chimney, 10. Connecting pipe, 11. Exhaust pipe, 12. First electric valve, 13. Fan, 14. Second electric valve, 15. Heat conducting plate, 16. Valve frame, 17. Discharge pipe, 18. Discharge pipe, 19. Valve core, 20. Motor. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] The present invention provides a flue gas post-combustion device and post-combustion method for utilizing waste heat. Figures 1 to 7 shown.

[0041] Example 1:

[0042] A flue reburning device for utilizing waste heat includes a heating frame 5, the interior of which is equipped with a flow equalizing plate 6, a reburner 7 and a heating pipe 8. Water to be heated can flow into the interior of the heating pipe 8. Then, an air intake pipe 1 is installed at one end of the heating frame 5, and a main chimney 9 is provided at the other end. The air intake pipe 1 is provided with a gas turbine air intake 2 and a fresh air air intake 3. The gas turbine air intake 2 is interconnected with the air outlet of the external gas turbine. A fresh air regulating valve 4 is installed inside the fresh air intake 3. The heating frame 5 is communicated with the main chimney 9 through a connecting pipe 10 and an exhaust pipe 11 respectively. A first electric valve 12 is installed inside the connecting pipe 10, and a fan 13 and a second electric valve 14 are installed inside the exhaust pipe 11.

[0043] The fresh air regulating valve 4 can control the on-off of the fresh air inlet 3, the first electric valve 12 can control the on-off of the connecting pipe 10, and the second electric valve 14 can control the on-off of the exhaust pipe 11. The fresh air regulating valve 4, the first electric valve 12 and the second electric valve 14 can all be remotely controlled on and off. Valves that can be remotely controlled are existing technologies and are now widely used, so they will not be elaborated in the present invention.

[0044] When the gas turbine is operating normally, the fresh air regulating valve 4 and the second electric valve 14 are closed, the first electric valve 12 is opened, and the gas exhausted by the gas turbine enters the interior of the heating frame 5. At this time, the afterburner 7 can be opened and closed or adjusted according to the change of the heat load. The afterburner 7 can perform afterburning on the gas exhausted by the gas turbine entering the interior of the heating frame 5, heat the water inside the heating pipe 8, and the gas generated by the combustion enters the interior of the main chimney 9 through the connecting pipe 10 and is discharged. In this process, the oxygen required for the combustion of the afterburner 7 is provided by the gas exhausted by the gas turbine (about 15% of the gas exhausted by the gas turbine is oxygen). In the above process, the interior of the heating frame 5 is in a positive pressure state, which allows the burned gas to be smoothly discharged through the main chimney 9.

[0045] The afterburner 7 is a prior art and has been widely used in waste heat boilers, combined cycle power generation and industrial kilns, so it will not be described in detail in the present invention.

[0046] When the gas turbine is shut down, the first electric valve 12 is closed, the fresh air regulating valve 4 and the second electric valve 14 are opened, and the fan 13 is started. At this time, under the action of the fan 13, the outside air enters the interior of the heating frame 5 through the fresh air inlet, providing oxygen for the combustion of the afterburner 7, so that the afterburner 7 can burn smoothly to heat the water inside the heating pipe 8. At this time, the burning gas enters the interior of the main chimney 9 through the exhaust pipe 11, and is then discharged through the main chimney 9. During this process, due to the fan 13, the interior of the heating frame 5 is in a state of slight negative pressure, so that the outside air can smoothly enter the interior of the heating frame 5.

[0047] Example 2:

[0048] On the basis of Example 1, in order to achieve a better heating effect of the water inside the heating pipe 8, a part of the heating pipe 8 inside the heating frame 5 is designed to be spiral, which increases the time for the water to flow inside the heating frame 5. At the same time, multiple groups of heat-conducting components are fixedly connected inside the heating pipe 8.

[0049] The heat conducting assembly includes a plurality of heat conducting sheets 15, which are made of an elastic material with high thermal conductivity (such as a heat conducting silicone gasket). The shape of the heat conducting sheet 15 is wavy, and one end of the heat conducting sheet 15 is a fixed end fixedly connected to the inner wall of the heating pipe 8, and the other end is a floating end, which is tilted toward the axis of the heating pipe 8. The heat conducting sheet 15 can quickly transfer heat from the pipe wall to the water flow, thereby improving the uniformity of heating. At the same time, the heat conducting sheet 15 can also destroy the laminar boundary layer formed by the water flow around the pipe wall, and promote the transfer of heat to the inside of the water flow. The wavy design of the heat conducting sheet 15 can increase the turbulence effect on the water and increase the contact area with the water, which can further improve the uniformity of heating and increase the effect of destroying the laminar boundary layer formed by the water flow around the pipe wall.

[0050] Example 3:

[0051] On the basis of the second embodiment, in order to avoid scale adhesion on the inner wall of the heating pipe 8 after long-term use, a switching valve is provided on the heating frame 5. The two ends of the heating pipe 8 are respectively connected to the switching valve. The switching valve includes a valve frame 16 and a valve core 19. The valve core 19 is rotatably mounted inside the valve frame 16 and driven by a motor 20 mounted on the valve frame 16. The two ends of the heating pipe 8 are symmetrical with respect to the axis of the valve frame 16. The valve frame 16 is also fixedly connected with an inlet pipe 17 and an outlet pipe 18. The inlet pipe 17 and the outlet pipe 18 are also symmetrical with respect to the axis of the valve frame 16. By rotating the motor 20, the valve core 19 is controlled to rotate inside the valve frame 16, thereby controlling the outlet. The inlet pipe 17 is respectively connected to the two ends of the heating pipe 8. When the discharge pipe 17 is connected to one end of the heating pipe 8, the discharge pipe 18 will be connected to the other end of the heating pipe 8, so that the direction of the water flow inside the heating pipe 8 can be adjusted. Because the material of the heat conducting plate 15 is elastic and the heat conducting plate 15 is provided with a floating end, the floating end of the heat conducting plate 15 will change accordingly according to the direction of the water flow inside the heating pipe 8, so as to avoid the formation of scale on the heat conducting plate 15. In addition, by regularly adjusting the direction of the water flow inside the heating pipe 8, the inner wall of the heating pipe 8 can be flushed from different directions, thereby avoiding the formation of scale on the inner wall of the heating pipe 8, which in turn affects the heating effect.

[0052] Example 4

[0053] Step 1: Close the first electric valve 12 to isolate the connecting pipe 10 from the interior of the heating frame 5;

[0054] Step 2: Open the fresh air regulating valve 4 and the second electric valve 14, open the fresh air inlet 3, and connect the exhaust pipe 11 to the heating frame 5;

[0055] Step 3: Start the fan 13 to allow the outside air to enter the interior of the heating frame 5 through the fresh air inlet 3 and the air inlet pipe 1;

[0056] Step 4: Start the afterburner 7 to heat the heating pipe 8.

[0057] Step 5: Start the motor 20 every 10 days to drive the valve core 19 to rotate 90 degrees.

[0058] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A flue gas post-combustion device for waste heat utilization, characterized in that: include: An air intake pipe (1), wherein the air intake pipe (1) is provided with a combustion engine air intake (2) and a fresh air intake (3), and a fresh air regulating valve (4) is installed inside the fresh air intake (3); A heating frame (5), one end of the heating frame (5) is connected to the air inlet pipe (1), and a flow equalizing plate (6), an afterburner (7), and a heating pipe (8) are sequentially installed inside the heating frame (5) in a direction away from the air inlet pipe (1); A main chimney (9), the main chimney (9) being located at one end of the heating frame (5) away from the air inlet pipe (1), and the main chimney (9) being connected to the heating frame (5) via a connecting pipe (10) and an exhaust pipe (11), a first electric valve (12) being installed inside the connecting pipe (10), and a fan (13) and a second electric valve (14) being installed inside the exhaust pipe (11); The interior of the heating pipe (8) is fixedly connected with a plurality of heat-conducting components, and the heat-conducting components include a plurality of heat-conducting sheets (15). The heat-conducting sheets (15) are made of a material with elasticity and high heat conductivity, and one end of the heat-conducting sheet (15) is a fixed end fixedly connected to the inner wall of the heating pipe (8), and the other end is a floating end, which is deflected toward the direction of the axis of the heating pipe (8); The heat conducting sheet (15) is wavy in shape; The plurality of heat conducting sheets (15) in two adjacent heat conducting components are staggeredly distributed; The heating pipe (8) is connected to a switching valve installed on the upper side of the heating frame (5), and the flow direction of water in the heating pipe (8) is adjusted by starting the switching valve.

2. The flue gas post-combustion device for waste heat utilization according to claim 1, characterized in that: The switching valve comprises: A valve frame (16), wherein the valve frame (16) is fixed on the heating frame (5), and an inlet pipe (17) and an outlet pipe (18) are fixedly connected to the annular surface of the valve frame (16); A valve core (19), wherein the valve core (19) is rotatably mounted inside the valve frame (16), and the valve core (19) is driven by a motor (20) mounted on the valve frame (16); Both ends of the heating pipe (8) are in communication with the interior of the valve frame (16), the inlet pipe (17) and the outlet pipe (18) are symmetrical about the axis of the valve frame (16), and the two ends of the heating pipe (8) are also symmetrical about the axis of the valve frame (16).

3. The flue gas post-combustion device for waste heat utilization according to claim 1, characterized in that: The heating pipe (8) is distributed in the form of a rectangular spiral inside the heating frame (5).

4. A supplementary combustion method for a flue supplementary combustion device according to claim 2, characterized in that: include: Step 1: Close the first electric valve (12) to separate the connecting pipe (10) from the interior of the heating frame (5); Step 2: Open the fresh air regulating valve (4) and the second electric valve (14), open the fresh air inlet (3), and connect the exhaust pipe (11) to the heating frame (5); Step 3: Start the fan (13) to allow the outside air to enter the interior of the heating frame (5) through the fresh air inlet (3) and the air inlet pipe (1); Step 4: starting the afterburner (7) to heat the heating pipe (8); Step 5: Start the motor (20) every 10 days to make the motor (20) drive the valve core (19) to rotate 90 degrees.

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