Low-nitrogen water tube boiler

Abstract

The present invention provides a low-nitrogen water-tube boiler, belonging to the technical field of heating equipment. A heating cavity is formed between the furnace body and the furnace chamber. The furnace body has a smoke exhaust cavity and an air inlet cavity near one end of the furnace chamber inlet. The furnace body has a smoke collecting cavity communicating with the furnace chamber outlet. A number of smoke tubes are inserted into the heating cavity, and both ends of the smoke tubes communicate with the smoke collecting cavity and the smoke exhaust cavity respectively. A number of water distribution pipes are arranged in the heating cavity, and a heat medium is filled in the heating cavity. The inlet of the furnace chamber is connected to an air inlet pipe, the air inlet pipe communicates with the air inlet cavity, the air inlet pipe is also connected to an air inlet connection pipe, the air inlet connection pipe is connected to an oxygen supply source, and a gas supply pipe is rotatably connected in the air inlet pipe. An impeller located in the smoke collecting cavity is fixedly arranged on the gas supply pipe. The gas supply pipe has a number of gas injection holes at the furnace chamber inlet, and an ignition device is arranged in the furnace chamber outside the gas injection holes. The present invention has the advantages of high heat utilization rate and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of heating equipment and relates to a low-nitrogen water-tube boiler. Background Art

[0002] A low-nitrogen boiler is a boiler with better exhaust gas emission performance and is more in line with the requirements of environmental protection and energy conservation. However, the existing boilers do not make full use of the flue gas. Most of them adopt the method of flue gas recirculation, making their structures complex, and it is difficult to control the recirculation amount of the flue gas.

[0003] After the flue gas is discharged from the furnace, in addition to preheating the incoming air, it needs to be condensed and then discharged through the chimney, and the heat utilization rate is relatively low. The main reason is that it is difficult to balance the flue gas discharge efficiency and the combustion efficiency. That is to say, if the flue gas is discharged too fast, the combustion efficiency can be increased, but the heat loss is also large. If the flue gas is discharged too slowly, the heat utilization rate is relatively high, but the heat generation efficiency will decrease. How to reduce the production of nitrogen oxides, increase the heat utilization rate, and not affect the total heat generation amount is a design problem of the boiler. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-nitrogen water-tube boiler for the above problems existing in the existing technology. The technical problem to be solved by the present invention is how to improve the heat utilization rate.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A low-nitrogen water-tube boiler, including a furnace body and a furnace chamber, characterized in that a heating cavity is formed between the furnace body and the furnace chamber. The furnace body has a smoke exhaust cavity and an air intake cavity near one end of the furnace chamber entrance. The furnace body has a smoke collecting cavity communicating with the furnace chamber outlet. A plurality of smoke pipes are inserted into the heating cavity. The two ends of the smoke pipes are respectively communicated with the smoke collecting cavity and the smoke exhaust cavity. A plurality of water distribution pipes are arranged in the heating cavity. The inlets of the water distribution pipes are communicated with a water inlet collecting cavity located on the outer wall of the furnace body, and the outlets of the water distribution pipes are communicated with a water outlet collecting cavity located on the outer wall of the furnace body. The heating cavity is filled with a heating medium;

[0006] The entrance of the furnace chamber is connected to an air inlet pipe, the air inlet pipe communicates with the air intake cavity, the air inlet pipe is also connected to an air intake connection pipe, the air intake connection pipe is connected to an oxygen supply source, a gas supply pipe is rotatably connected in the air inlet pipe, an impeller located in the smoke collecting cavity is fixedly arranged on the gas supply pipe, a plurality of spray holes are arranged on the gas supply pipe at the entrance of the furnace chamber, and an ignition device is arranged in the furnace chamber outside the spray holes.

[0007] Further, a check valve is arranged in the air intake connection pipe. The smoke exhaust cavity and the air intake cavity are separated by a piston. A return spring is connected between the piston and the furnace body. The furnace body is provided with a smoke exhaust connection pipe that can communicate with the smoke exhaust cavity. The peripheral wall of the piston can block the entrance of the smoke exhaust connection pipe.

[0008] The water inlet collecting chamber is connected to a cold water source, and the water outlet collecting chamber is connected to a hot water delivery pipe for use by a water supply and use device. After use, the cooled water can also be circulated back to the water inlet collecting chamber.

[0009] Furthermore, a number of flame separation wheels are arranged outside the gas supply pipe, and the flame separation wheels are arranged at intervals.

[0010] Furthermore, the heat medium is water.

[0011] Furthermore, the flame separation wheels can guide the air flow to flow from the inlet of the furnace to the outlet.

[0012] Furthermore, the impeller rotates under the action of the hot gas at the outlet of the furnace and can drive the flue gas flow to disperse to the outside of the impeller.

[0013] Furthermore, the water inlet collecting chamber is arranged on the furnace body at one end close to the furnace inlet, and the water outlet collecting chamber is arranged on the furnace body at one end close to the furnace outlet.

[0014] Based on the fact that increasing the air intake, extending the flame, and forming a hollow flame can have a positive effect on the thermal efficiency of the boiler, the uniform heating of the heat medium, and the reduction of nitrogen oxide production, this solution adopts a rotary gas supply pipe. Its rotation power comes from the impact force of the exhaust gas at the end of the furnace. A number of flame separation wheels are arranged on the outer wall of the gas supply pipe inside the furnace. During the rotation of the gas supply pipe, the flame separation wheels guide the mixed gas in the furnace, driving it to rush out of the end of the furnace at a faster speed, and thus forming a relative negative pressure at the end of the intake pipe. This relative negative pressure is relative to the situation without flame separation wheels. The increase in the air intake can promote more complete combustion of the gas, relatively reduce the proportion of nitrogen oxides in the exhaust gas, and also make the flame tend to be distributed on the wall surface of the furnace. In the traditional furnace, the utilization rate of the flame in the middle is low, most of the heat exists in the flue gas, and the concentration of the flue gas affects the full combustion, promoting the generation of a large amount of unburned intermediates; through the rotation of the flame separation wheels, the flame is extended and supported to expand outward, and the inner wall of the furnace is heated more evenly, and the heating effect of the heating chamber is better.

[0015] This solution adopts the intermittent air intake and intermittent smoke exhaust methods, so that part of the flue gas can be combusted again. Specifically, when the pressure in the smoke exhaust cavity is small, the return spring drives the piston close to the smoke exhaust cavity. The circumferential surface of the piston blocks the inlet of the smoke exhaust pipe, and the flue gas is temporarily in a state where it is not allowed to be discharged. The flue gas accumulates in the smoke exhaust cavity until the pressure in the smoke exhaust cavity increases and the piston moves towards the air intake cavity. During the process of the piston moving towards the air intake cavity, the check valve blocks the air intake cavity, and the air pressure inside it increases and enters the furnace, which can achieve the effect of air intake pressurization. At the same time, as the piston moves, the circumferential surface of the piston gradually "opens" the inlet of the smoke exhaust pipe, and the high-pressure flue gas in the smoke exhaust cavity is discharged. Since the flue gas cannot be discharged in a short period of time, part of the flue gas accumulated in the furnace is mixed with high-pressure fresh air and gas and can be combusted again under the ignition state.

[0016] The "prohibition of discharging" of the flue gas can also make the heat be absorbed by the heating medium in the heating cavity as much as possible. The agitated flue gas can also perform a certain effect of reverse cleaning on the smoke pipes, extending the maintenance period of the smoke pipe ash accumulation.

[0017] During the process of the piston approaching the smoke exhaust cavity, it is the process of fresh air being inhaled into the air intake cavity. This part of the gas is preheated in the air intake cavity close to the smoke exhaust cavity and is squeezed into the furnace during the process of the piston approaching the air intake cavity, realizing the automatic inhalation of air. The control of the air supply volume can be controlled by a pressure limiting valve set on the air intake path of the fresh air.

[0018] In traditional boilers, the flue gas discharged from the furnace impacts the furnace wall at the end of the furnace and then turns back to the smoke exhaust pipe, causing part of the flue gas to choke back into the furnace, affecting the length of the flame in the furnace, especially the flame at the end of the furnace. In this solution, an impeller is set to guide the flue gas so that it diffuses outward from the smoke collecting cavity and then better enters the smoke exhaust pipe.

[0019] The hot gas in the furnace tends to be discharged in a spiral state under the rotation of the flame dividing wheel. Especially at the end of the furnace, it can wash the inner wall of the furnace to reduce ash accumulation. During the discharge process of the gas, centrifugal force is also generated due to the rotation of the gas supply pipe, making the blending effect with air or the mixture better and the gas mixture more uniform. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of this boiler in a state where the discharge of flue gas is not allowed.

[0021] Figure 2 It is a schematic structural diagram of this boiler in a state of discharging flue gas.

[0022] Figure 3 is Figure 1 The enlarged view of the partial A in

[0023] Figure 4 isFigure 2 Enlarged view of local B

[0024] In the figure, 11 is the furnace body; 12 is the furnace chamber; 21 is the heating cavity; 22 is the smoke exhaust cavity; 23 is the air inlet cavity; 24 is the smoke collecting cavity; 3 is the smoke pipe; 41 is the water distribution pipe; 42 is the water inlet and collecting cavity; 43 is the water outlet and collecting cavity; 51 is the gas inlet pipe; 52 is the gas inlet connection pipe; 53 is the check valve; 54 is the piston; 55 is the return spring; 61 is the gas supply pipe; 62 is the impeller; 63 is the gas injection hole; 7 is the ignition device; 8 is the smoke exhaust connection pipe; 9 is the flame separation wheel. Specific embodiments

[0025] The following are specific embodiments of the present invention and in conjunction with the accompanying drawings, the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0026] As Figures 1 to 4 shown, it includes a furnace body 11 and a furnace chamber 12. A heating cavity 21 is formed between the furnace body 11 and the furnace chamber 12. There is a smoke exhaust cavity 22 and an air inlet cavity 23 near one end of the inlet of the furnace chamber 12 inside the furnace body 11. There is a smoke collecting cavity 24 communicating with the outlet of the furnace chamber 12 inside the furnace body 11. A number of smoke pipes 3 are inserted into the heating cavity 21. Both ends of the smoke pipe 3 are respectively communicated with the smoke collecting cavity 24 and the smoke exhaust cavity 22. A number of water distribution pipes 41 are arranged in the heating cavity 21. The inlets of the water distribution pipes 41 are communicated with a water inlet and collecting cavity 42 located on the outer wall surface of the furnace body 11. The outlets of the water distribution pipes 41 are communicated with a water outlet and collecting cavity 43 located on the outer wall surface of the furnace body 11. A heating medium is filled in the heating cavity 21;

[0027] The inlet of the furnace chamber 12 is connected to a gas inlet pipe 51. The gas inlet pipe 51 communicates with the air inlet cavity 23. The gas inlet pipe 51 is also connected to a gas inlet connection pipe 52. The gas inlet connection pipe 52 is connected to an oxygen supply source. A gas supply pipe 61 is rotatably connected inside the gas inlet pipe 51. An impeller 62 located in the smoke collecting cavity 24 is fixedly arranged on the gas supply pipe 61. A number of gas injection holes 63 are provided at the inlet of the furnace chamber 12 on the gas supply pipe 61. An ignition device 7 is arranged inside the furnace chamber 12 outside the gas injection holes 63.

[0028] A check valve 53 is arranged inside the gas inlet connection pipe 52. The smoke exhaust cavity 22 and the air inlet cavity 23 are separated by a piston 54. A return spring 55 is connected between the piston 54 and the furnace body 11. A smoke exhaust connection pipe 8 capable of communicating with the smoke exhaust cavity 22 is arranged on the furnace body 11. The peripheral wall of the piston 54 can block the inlet of the smoke exhaust connection pipe 8.

[0029] The water inlet and collecting cavity 42 is connected to a cold water source. The water outlet and collecting cavity 43 is connected to a hot water delivery pipe for use by water-consuming equipment, or the cooled water can be circulated back to the water inlet and collecting cavity 42 after use.

[0030] A number of flame separation wheels 9 are provided outside the gas supply pipe 61, and the flame separation wheels 9 are arranged at intervals.

[0031] The heat-absorbing medium is water or other medium with a boiling point higher than that of water.

[0032] The flame separation wheel 9 can guide the air flow to flow from the inlet to the outlet of the furnace chamber 12.

[0033] The impeller 62 rotates under the action of the hot gas at the outlet of the furnace chamber 12 and can drive the flue gas flow to disperse to the outside of the impeller 62.

[0034] The water inlet and collection chamber 42 is arranged on the furnace body 11 at one end close to the inlet of the furnace chamber 12, and the water outlet and collection chamber 43 is arranged on the furnace body 11 at one end close to the outlet of the furnace chamber 12.

[0035] Based on the fact that increasing the air intake, extending the flame, and forming a hollow flame can have a positive effect on the thermal utilization rate of the boiler, the heat absorption uniformity of the heat-absorbing medium, and reducing the production of nitrogen oxides, this solution adopts a rotary gas supply pipe 61, the rotation power of which comes from the impact force of the waste gas at the end of the furnace chamber 12. A number of flame separation wheels 9 located in the furnace chamber 12 are arranged on the outer wall of the gas supply pipe 61. The flame separation wheels 9 guide the mixed gas in the furnace chamber 12 during the rotation of the gas supply pipe 61, driving it to rush out of the end of the furnace chamber 12 at a faster speed, and thus forming a relative negative pressure at the end of the intake pipe 51. This relative negative pressure is relative to the situation where the flame separation wheels 9 are not provided. The increase in the air intake can promote more complete combustion of the gas, relatively reduce the proportion of nitrogen oxides in the waste gas, and also make the flame tend to be distributed on the wall surface of the furnace chamber 12. In the traditional furnace chamber 12, the utilization rate of the middle part of the flame is low, most of the heat exists in the flue gas, and the concentration of the flue gas affects the complete combustion, promoting the generation of a large number of incompletely burned intermediates; through the rotation of the flame separation wheels 9, the flame is extended and supported from the inside to expand outward, and the inner wall of the furnace chamber 12 is heated more evenly, and the heat absorption effect of the heat absorption chamber 21 is better.

[0036] This solution adopts the intermittent intake air and intermittent smoke exhaust methods, so that part of the flue gas can be combusted again. Specifically, when the pressure in the smoke exhaust cavity 22 is relatively small, the return spring 55 drives the piston 54 to approach the smoke exhaust cavity 22. The peripheral surface of the piston 54 blocks the inlet of the smoke exhaust pipe 8, and the flue gas is temporarily in a state where it is not allowed to be discharged. The flue gas accumulates in the smoke exhaust cavity 22 until the pressure in the smoke exhaust cavity 22 increases to cause the piston 54 to move towards the intake air cavity 23. During the process of the piston 54 moving towards the intake air cavity 23, the check valve 53 blocks the intake air cavity 23, and the air pressure inside it increases and enters the furnace 12, which can achieve the effect of intake air pressurization. At the same time, as the piston 54 moves, the peripheral surface of the piston 54 gradually "opens" the inlet of the smoke exhaust pipe 8, and the high-pressure flue gas in the smoke exhaust cavity 22 is discharged. Since the flue gas cannot be discharged within a short period of time, part of the flue gas accumulated in the furnace 12 is mixed with high-pressure fresh air and gas, and can be combusted again under the ignition state.

[0037] The "forbidden discharge" of the flue gas can also enable the heat to be absorbed by the heat-absorbing medium in the heat-absorbing cavity 21 as much as possible. The agitated flue gas can also perform a certain effect of reverse cleaning on the smoke pipe 3, and extend the maintenance period of the ash accumulation in the smoke pipe 3.

[0038] During the process of the piston 54 approaching the smoke exhaust cavity 22, it is the process of fresh air being inhaled into the intake air cavity 23. This part of the gas is preheated in the intake air cavity 23 close to the smoke exhaust cavity 22 and is squeezed into the furnace 12 during the process of the piston 54 approaching the intake air cavity 23, realizing the automatic inhalation of air. The control of the air supply volume can be controlled by a pressure-limiting valve arranged on the intake air path of the fresh air.

[0039] In a traditional boiler, the flue gas discharged from the furnace 12 impacts the furnace wall at the end of the furnace 12 and then turns back to the smoke exhaust pipe 3, causing part of the flue gas to choke back into the furnace 12, affecting the length of the flame in the furnace 12, especially the flame at the end of the furnace 12. In this solution, an impeller 62 is provided to guide the flue gas, so that it diffuses outward from the smoke collecting cavity 24, and then better enters the smoke exhaust pipe 3.

[0040] The hot gas in the furnace 12 tends to be discharged in a spiral state under the rotation of the flame dividing wheel 9. Especially at the end of the furnace 12, it can wash the inner wall of the furnace 12 to reduce ash accumulation. During the discharge process of the gas, a centrifugal force is also generated due to the rotation of the gas supply pipe 61, making the blending effect with air or the mixture better and the gas mixing more uniform.

[0041] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the technical field to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. Low-nitrogen water tube boiler, comprising a furnace body (11) and a furnace chamber (12), characterized in that, a heating cavity (21) is formed between the furnace body (11) and the furnace chamber (12), a smoke exhaust cavity (22) and an air inlet cavity (23) are provided in the furnace body (11) near one end of the inlet of the furnace chamber (12), a smoke collecting cavity (24) communicating with the outlet of the furnace chamber (12) is provided in the furnace body (11), a plurality of smoke tubes (3) are inserted in the heating cavity (21), both ends of the smoke tubes (3) communicate with the smoke collecting cavity (24) and the smoke exhaust cavity (22) respectively, a plurality of water distribution pipes (41) are arranged in the heating cavity (21), the inlets of the water distribution pipes (41) communicate with a water inlet collecting cavity (42) located on the outer wall surface of the furnace body (11), the outlets of the water distribution pipes (41) communicate with a water outlet collecting cavity (43) located on the outer wall surface of the furnace body (11), and a heating medium is filled in the heating cavity (21); the inlet of the furnace chamber (12) is connected to an air inlet pipe (51), the air inlet pipe (51) communicates with the air inlet cavity (23), the air inlet pipe (51) is further connected to an air inlet connecting pipe (52), the air inlet connecting pipe (52) is connected to an oxygen supply source, a gas supply pipe (61) is rotatably connected in the air inlet pipe (51), an impeller (62) located in the smoke collecting cavity (24) is fixedly arranged on the gas supply pipe (61), a plurality of gas injection holes (63) are provided on the gas supply pipe (61) at the inlet of the furnace chamber (12), and an ignition device (7) is arranged in the furnace chamber (12) outside the gas injection holes (63).

2. The low-nitrogen water tube boiler according to claim 1, characterized in that, a check valve (53) is arranged in the air inlet connecting pipe (52), the smoke exhaust cavity (22) and the air inlet cavity (23) are separated by a piston (54), a return spring (55) is connected between the piston (54) and the furnace body (11), a smoke exhaust connecting pipe (8) capable of communicating with the smoke exhaust cavity (22) is arranged on the furnace body (11), and the peripheral wall of the piston (54) can block the inlet of the smoke exhaust connecting pipe (8).

3. The low-nitrogen water tube boiler according to claim 1 or 2, characterized in that, a plurality of flame separation wheels (9) are arranged outside the gas supply pipe (61), and the flame separation wheels (9) are arranged at intervals.

4. The low-nitrogen water tube boiler according to claim 1 or 2, characterized in that, the heating medium is water.

5. The low-nitrogen water tube boiler according to claim 3, characterized in that, the flame separation wheels (9) can guide the air flow to flow from the inlet to the outlet direction of the furnace chamber (12).

6. The low-nitrogen water tube boiler according to claim 1 or 2, characterized in that, the impeller (62) is rotated by the hot gas at the outlet of the furnace chamber (12) and can drive the smoke gas flow to disperse to the outside of the impeller (62).

7. The low-nitrogen water tube boiler according to claim 1 or 2, characterized in that, the water inlet collecting cavity (42) is arranged on the furnace body (11) near one end of the inlet of the furnace chamber (12), and the water outlet collecting cavity (43) is arranged on the furnace body (11) near one end of the outlet of the furnace chamber (12).

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