Flue gas recirculation combustion system

Abstract

The present invention discloses a flue gas recirculation combustion system, comprising a housing and a mixing mechanism; a flue gas purification pipe is provided at the upper end of the housing, and both the left and right ends of the flue gas purification pipe penetrate through the interior of the housing. A dust filter bag is installed on the left inner arc surface of the flue gas purification pipe. A first branch pipe is provided on the left inner wall of the flue gas purification pipe, and the right end of the first branch pipe is a closed structure. A second branch pipe and a third branch pipe are respectively provided between the right inner wall of the first branch pipe and the left inner wall of the flue gas purification pipe. The third branch pipe is located inside the second branch pipe, and a desulfurizing agent is filled between the outer arc surface of the third branch pipe and the inner arc surface of the second branch pipe. For this flue gas recirculation combustion system, the structure of the boiler flue gas recirculation combustion system is more compact. The purified flue gas is mixed with the fresh air flowing in a spiral trajectory in multiple small amounts, reducing the time required for mixing, improving the uniformity of the mixing of the flue gas and the fresh air, and enhancing the effect of the boiler flue gas recirculation combustion.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler flue gas recirculation, and specifically relates to a flue gas recirculation combustion system. Background Technique

[0002] There are various application technologies for boiler flue gas recirculation, including forms such as oxygen-enriched combustion and low-temperature combustion. Good effects have been achieved after investigation, and it is also called the waste gas recirculation process technology. Boiler flue gas recirculation is to recycle the flue gas after combustion back to the boiler for secondary combustion by recovering the waste heat, mainly to control the concentration of oxides, reduce the high temperature in the combustion area, reduce the formation of NOx, and raise the preheating temperature of the air before it enters the boiler again to reduce energy loss. In the prior art, boiler flue gas recirculation combustion can be mainly divided into several steps such as flue gas collection, flue gas purification, flue gas cooling, and flue gas mixing. Among them, flue gas mixing refers to mixing the treated flue gas with fresh air, and then transporting it back to the boiler burner for combustion again. The common mixing method is to inject the flue gas and fresh air into a flowing space together to mix the flue gas and fresh air. During the mixing process, the proportion of the flue gas is relatively large, and the mixing time required is relatively long, which easily leads to uneven mixing of the flue gas and fresh air and affects the flue gas recirculation combustion effect. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the existing defects, provide a flue gas recirculation combustion system, mix the purified flue gas with the fresh air flowing in a spiral trajectory in multiple small amounts, reduce the mixing time required, improve the uniformity of mixing of the flue gas and fresh air, and increase the effect of boiler flue gas recirculation combustion, which can effectively solve the problems in the background technique.

[0004] To achieve the above object, the present invention provides the following technical solution: A flue gas recirculation combustion system, including a housing and a mixing mechanism;

[0005] A flue gas purification pipe is provided at the upper end of the housing. Both the left and right ends of the flue gas purification pipe penetrate the inside of the housing. A dust filter bag is installed on the left inner arc surface of the flue gas purification pipe. A first branch pipe is provided on the left inner wall of the flue gas purification pipe. The right end of the first branch pipe is a closed structure. A second branch pipe and a third branch pipe are respectively provided between the right inner wall of the first branch pipe and the left inner wall of the flue gas purification pipe. The third branch pipe is located inside the second branch pipe. A desulfurizing agent is filled between the outer arc surface of the third branch pipe and the inner arc surface of the second branch pipe. An activated carbon is filled between the outer arc surface of the second branch pipe and the inner arc surface of the first branch pipe.

[0006] The mixing mechanism is arranged at the lower end of the housing, making the structure of the boiler flue gas recirculation combustion system more compact, reducing the floor space occupied by the boiler flue gas recirculation combustion system, mixing the purified flue gas with the fresh air flowing in a spiral trajectory in multiple small amounts, reducing the time required for mixing, improving the uniformity of the mixing of the flue gas and the fresh air, enhancing the effect of the boiler flue gas recirculation combustion, making the combustion of the boiler more complete, and reducing environmental pollution.

[0007] Furthermore, the mixing mechanism includes a flue gas mixing pipe, an air delivery pipe, and injection holes. The flue gas mixing pipe is arranged at the lower end of the housing, and both the left and right ends of the flue gas mixing pipe penetrate the interior of the housing. Injection holes are respectively arranged on the outer arc surface of the flue gas mixing pipe. The air delivery pipe is arranged in the middle of the housing. The upper end of the air delivery pipe is connected to the interior of the flue gas purification pipe, and the lower end of the air delivery pipe is fixedly connected to the outer arc surface of the flue gas mixing pipe and is connected to the injection holes to mix the flue gas with the fresh air.

[0008] Furthermore, the air delivery pipe includes a Z-shaped pipe, an annular pipe, and an injection pipe. The Z-shaped pipe is arranged in the middle of the housing. The upper end of the Z-shaped pipe is connected to the interior of the flue gas purification pipe, and the lower end of the Z-shaped pipe is provided with an annular pipe. The annular pipe is fixedly connected to the outer arc surface of the flue gas mixing pipe. Injection pipes are respectively arranged on the left side surface of the annular pipe. The Z-shaped pipe, the annular pipe, and the injection pipe are sequentially connected, and the injection pipe is connected to the injection holes to deliver the purified flue gas to the mixing space.

[0009] Furthermore, the mixing mechanism further includes a guide pipe and a guide spiral fin. The guide pipe is located inside the flue gas mixing pipe. The right end of the guide pipe is a closed conical structure. A guide spiral fin is arranged between the outer arc surface of the guide pipe and the inner arc surface of the flue gas mixing pipe to guide the flow trajectory of the fresh air.

[0010] Furthermore, the mixing mechanism further includes a fan. The fan is located on the left side of the housing. The air inlet of the fan is connected to the left end of the flue gas mixing pipe to provide power for the flow of the fresh air.

[0011] Furthermore, a cooling water pipe is arranged inside the horizontal pipe body of the Z-shaped pipe. Both the left and right ends of the cooling water pipe penetrate the interior of the housing to cool the purified flue gas.

[0012] Furthermore, an electric fan is arranged inside the vertical pipe at the upper end of the Z-shaped pipe to provide power for the purified flue gas to enter the interior of the Z-shaped pipe.

[0013] Furthermore, air holes are respectively opened on the outer arc surfaces of the first branch pipe, the second branch pipe, and the third branch pipe to ensure the smooth flow of the flue gas.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] 1. During installation, the flue gas generated by the boiler operation enters the interior of the flue gas purification pipe. The dust in the flue gas is filtered by the dust filter bag, and the flue gas is purified by desulfurizing agent and activated carbon. The purified flue gas passes through the pores on the surface of the first branch pipe and is discharged from the right end of the flue gas purification pipe. Start the electric fan to make a part of the purified flue gas enter the interior of the Z-shaped pipe. The flowing water in the cooling water pipe is used to cool the flue gas and reduce its temperature. The cooled flue gas will enter the interior of the flue gas mixing pipe, where the flue gas is mixed with fresh air. Then the mixed air will return to the boiler interior to participate in combustion again. Through the recirculation combustion of the flue gas, the pollution of the boiler operation to the external environment is reduced. The flue gas purification component, flue gas cooling component and flue gas mixing component are centrally arranged, making the structure of the boiler flue gas recirculation combustion system more compact, reducing the floor space of the boiler flue gas recirculation combustion system, and facilitating the use of the boiler flue gas recirculation combustion system.

[0016] 2. Under the guidance of the diversion pipe and the diversion spiral fin, the fresh air flows along the spiral groove cavity formed by the flue gas mixing pipe, the diversion pipe and the diversion spiral fin. Through the transportation of the Z-shaped pipe, the annular pipe and the injection pipe, the purified flue gas enters the interior of the flue gas mixing pipe from the injection holes, and the purified flue gas is mixed with the fresh air flowing in a spiral trajectory in small amounts and multiple times, reducing the mixing time required, improving the uniformity of the mixing of the flue gas and the fresh air, increasing the effect of the boiler flue gas recirculation combustion, making the combustion of the boiler more complete, and reducing the pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the present invention;

[0018] Figure 2 is a schematic structural diagram of the front view section of the whole device of the present invention;

[0019] Figure 3 is a schematic structural diagram of the interior of the housing of the present invention;

[0020] Figure 4 is a schematic structural diagram of the side view section of the whole device of the present invention;

[0021] Figure 5 is Figure 4 an enlarged view of the marked position A in

[0022] Figure 6 is a schematic top view structural diagram of the cooling water pipe of the present invention.

[0023] In the figure: 1 - housing, 2 - flue gas purification pipe, 3 - first branch pipe, 4 - second branch pipe, 5 - third branch pipe, 6 - dust filter bag, 7 - activated carbon, 8 - desulfurizer, 9 - mixing mechanism, 91 - flue gas mixing pipe, 92 - gas transmission pipe, 921 - Z-shaped pipe, 922 - annular pipe, 923 - injection pipe, 93 - diversion pipe, 94 - diversion spiral fin, 95 - injection hole, 96 - fan, 10 - control unit, 11 - cooling water pipe, 12 - electric fan. Specific implementation manner

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Please refer to Figures 1-6 , this embodiment provides a flue gas recirculation combustion system, including a housing 1 and a mixing mechanism 9.

[0026] A flue gas purification pipe 2 is provided at the upper end of the housing 1 to provide a space for the purification of flue gas. Both the left and right ends of the flue gas purification pipe 2 penetrate the inside of the housing 1. A dust filter bag 6 is installed on the left inner arc surface of the flue gas purification pipe 2. A first branch pipe 3 is provided on the left inner wall of the flue gas purification pipe 2. The right end of the first branch pipe 3 is a closed structure. A second branch pipe 4 and a third branch pipe 5 are respectively provided between the right inner wall of the first branch pipe 3 and the left inner wall of the flue gas purification pipe 2. The third branch pipe 5 is located inside the second branch pipe 4. A desulfurizer 8 is filled between the outer arc surface of the third branch pipe 5 and the inner arc surface of the second branch pipe 4. An activated carbon 7 is filled between the outer arc surface of the second branch pipe 4 and the inner arc surface of the first branch pipe 3. When the flue gas flows inside the flue gas purification pipe 2, the dust in the flue gas is filtered by the dust filter bag 6, and then the flue gas is purified by the desulfurizer 8 and the activated carbon 7. The purified flue gas passes through the pores on the surface of the first branch pipe 3 and is discharged from the right end of the flue gas purification pipe 2. A control unit 10 is provided on the front surface of the housing 1 to control the start and stop of the overall device. The input end of the control unit 10 is electrically connected to an external power source. Pores are provided on the outer arc surfaces of the first branch pipe 3, the second branch pipe 4, and the third branch pipe 5 to ensure the smooth flow of the flue gas;

[0027] The mixing mechanism 9 is arranged at the lower end of the housing 1. The mixing mechanism 9 includes a flue gas mixing pipe 91, a gas transmission pipe 92, and injection holes 95. The flue gas mixing pipe 91 is arranged at the lower end of the housing 1. Both the left and right ends of the flue gas mixing pipe 91 penetrate through the interior of the housing 1. Injection holes 95 are respectively arranged on the outer arc surface of the flue gas mixing pipe 91. The gas transmission pipe 92 is arranged in the middle of the housing 1. The upper end of the gas transmission pipe 92 is connected to the interior of the flue gas purification pipe 2. The lower end of the gas transmission pipe 92 is fixedly connected to the outer arc surface of the flue gas mixing pipe 91 and is connected to the injection holes 95, providing a space for the mixing of flue gas and fresh air. The gas transmission pipe 92 includes a Z-shaped pipe 921, an annular pipe 922, and an injection pipe 923. The Z-shaped pipe 921 is arranged in the middle of the housing 1. The upper end of the Z-shaped pipe 921 is connected to the interior of the flue gas purification pipe 2. The lower end of the Z-shaped pipe 921 is provided with an annular pipe 922. The annular pipe 922 is fixedly connected to the outer arc surface of the flue gas mixing pipe 91. Injection pipes 923 are respectively arranged on the left side surface of the annular pipe 922. The Z-shaped pipe 921, the annular pipe 922, and the injection pipes 923 are connected in sequence. The injection pipes 923 are connected to the injection holes 95, uniformly transporting the purified flue gas into the interior of the flue gas mixing pipe 91. The mixing mechanism 9 further includes a diversion pipe 93 and a diversion spiral fin 94. The diversion pipe 93 is located inside the flue gas mixing pipe 91. The right end of the diversion pipe 93 is a closed conical structure. A diversion spiral fin 94 is arranged between the outer arc surface of the diversion pipe 93 and the inner arc surface of the flue gas mixing pipe 91, guiding the flow trajectory of the fresh air, so that the fresh air flows along the spiral groove cavity formed by the flue gas mixing pipe 91, the diversion pipe 93, and the diversion spiral fin 94. The mixing mechanism 9 further includes a fan 96. The fan 96 is located on the left side of the housing 1. The air inlet of the fan 96 is connected to the left end of the flue gas mixing pipe 91. The input end of the fan 96 is electrically connected to the output end of the control unit 10, providing power for the fresh air to enter the interior of the flue gas mixing pipe 91. A cooling water pipe 11 is arranged inside the horizontal pipe body of the Z-shaped pipe 921. Both the left and right ends of the cooling water pipe 11 penetrate through the interior of the housing 1. When the flue gas flows inside the Z-shaped pipe 921, the water flowing inside the cooling water pipe 11 is used to cool the flue gas, reducing the temperature of the flue gas. An electric fan 12 is arranged inside the vertical pipe at the upper end of the Z-shaped pipe 921. The input end of the electric fan 12 is electrically connected to the output end of the control unit 10, providing power for the purified flue gas to enter the interior of the Z-shaped pipe 921.

[0028] The working principle of a flue gas recirculation combustion system provided by the present invention is as follows:

[0029] During installation, the left end of the flue gas purification pipe 2 is connected to the flue gas outlet of the boiler, and the right end of the flue gas purification pipe 2 is connected to the flue gas inlet of the boiler chimney. The outlet pipe of the fan 96 is connected to the air inlet of the boiler. When in use, the flue gas generated by the operation of the boiler will enter the interior of the flue gas purification pipe 2 under the action of an external induced draft fan. First, the dust in the flue gas is filtered by the dust filter bag 6, and then the flue gas is purified by the desulfurizing agent 8 and the activated carbon 7. The purified flue gas passes through the air holes on the surface of the first branch pipe 3 and is discharged from the right end of the flue gas purification pipe 2. At the same time, the fan 96 is started, and the fresh air outside is made to enter the interior of the flue gas mixing pipe 91 through the right end of the flue gas mixing pipe 91 by the fan 96, and under the guidance of the diversion pipe 93 and the diversion spiral fins 94, the fresh air flows along the spiral groove cavity formed by the flue gas mixing pipe 91, the diversion pipe 93 and the diversion spiral fins 94. While the fresh air is flowing, the electric fan 12 is started to make a part of the purified flue gas enter the interior of the Z-shaped pipe 921. During the process of the purified flue gas flowing in the Z-shaped pipe 921, the water flowing in the cooling water pipe 11 is used to cool the flue gas and reduce the temperature of the flue gas. Then, through the transportation of the annular pipe 922 and the injection pipe 923, it enters the interior of the flue gas mixing pipe 91 from the injection holes 95, and the purified flue gas is mixed with the fresh air flowing in a spiral trajectory in small amounts multiple times to ensure the uniformity of the mixing of the flue gas and the fresh air. The mixed air will flow back into the boiler interior to participate in combustion again. Through the recirculation combustion of the flue gas, the pollution of the external environment caused by the use of the boiler is reduced.

[0030] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A flue gas recirculation combustion system, characterized in that: It comprises a housing (1) and a mixing mechanism (9); A flue gas purification pipe (2) is provided at the upper end of the shell (1), and both left and right ends of the flue gas purification pipe (2) pass through the interior of the shell (1). A dust filter bag (6) is installed at the left end of the inner arc surface of the flue gas purification pipe (2). A branch pipe 1 (3) is provided on the left inner wall of the flue gas purification pipe (2), and the right end of the branch pipe 1 (3) is a closed structure. A branch pipe 2 (4) and a branch pipe 3 (5) are provided between the right inner wall of the branch pipe 1 (3) and the left inner wall of the flue gas purification pipe (2), respectively. The branch pipe 3 (5) is located inside the branch pipe 2 (4), and a desulfurizer (8) is filled between the outer arc surface of the branch pipe 3 (5) and the inner arc surface of the branch pipe 2 (4), and activated carbon (7) is filled between the outer arc surface of the branch pipe 2 (4) and the inner arc surface of the branch pipe 1 (3); The mixing mechanism (9) is arranged at the lower end of the housing (1); The mixing mechanism (9) comprises a flue gas mixing pipe (91), a gas delivery pipe (92) and a gas injection hole (95); the flue gas mixing pipe (91) is arranged at the lower end of the shell (1); both left and right ends of the flue gas mixing pipe (91) pass through the interior of the shell (1); the outer arc surface of the flue gas mixing pipe (91) is respectively provided with gas injection holes (95); the gas delivery pipe (92) is arranged in the middle of the shell (1); the upper end of the gas delivery pipe (92) is connected to the interior of the flue gas purification pipe (2); and the lower end of the gas delivery pipe (92) is fixedly connected to the outer arc surface of the flue gas mixing pipe (91) and is connected to the gas injection hole (95); The gas delivery pipe (92) comprises a Z-shaped pipe (921), an annular pipe (922) and an air injection pipe (923); the Z-shaped pipe (921) is arranged in the middle of the shell (1); the upper end of the Z-shaped pipe (921) is connected to the inside of the flue gas purification pipe (2); the lower end of the Z-shaped pipe (921) is provided with an annular pipe (922); the annular pipe (922) is fixedly connected to the outer arc surface of the flue gas mixing pipe (91); the left side of the annular pipe (922) is provided with an air injection pipe (923); the Z-shaped pipe (921), the annular pipe (922) and the air injection pipe (923) are connected in sequence; and the air injection pipe (923) is connected to the air injection hole (95).

2. A flue gas recirculation combustion system according to claim 1, characterized in that: The mixing mechanism (9) further comprises a flow guide pipe (93) and a flow guide spiral sheet (94); the flow guide pipe (93) is located inside the smoke mixing pipe (91); the right end of the flow guide pipe (93) is a closed conical structure; a flow guide spiral sheet (94) is provided between the outer arc surface of the flow guide pipe (93) and the inner arc surface of the smoke mixing pipe (91).

3. A flue gas recirculation combustion system according to claim 2, characterized in that: The mixing mechanism (9) further comprises a fan (96), wherein the fan (96) is located on the left side of the housing (1), and an air inlet of the fan (96) is connected to the left end of the smoke mixing pipe (91).

4. A flue gas recirculation combustion system according to claim 3, characterized in that: A cooling water pipe (11) is provided inside the horizontal tube body of the Z-shaped tube (921), and both left and right ends of the cooling water pipe (11) pass through the interior of the shell (1).

5. A flue gas recirculation combustion system according to claim 4, characterized in that: An electric fan (12) is provided inside the vertical pipe at the upper end of the Z-shaped pipe (921).

6. A flue gas recirculation combustion system according to claim 5, characterized in that: The outer arc surfaces of the branch pipe 1 (3), the branch pipe 2 (4) and the branch pipe 3 (5) are all provided with air holes.

Images