Low-nitrogen gas-steam boiler

Abstract

The utility model relates to the technical field of boilers, in particular to a low-nitrogen gas steam boiler which comprises a boiler body, two groups of water pipes are arranged in the boiler body and include an ascending pipe and a descending pipe, the descending pipe is located on the periphery of the ascending pipe, a gas distributor is arranged on one side of the ascending pipe, and a burner is installed on the side, facing the ascending pipe, of the gas distributor. A preheater is arranged on the outer side of the furnace body, one side of the furnace body is connected with a flue, a smoke pipe is vertically installed in the middle of the interior of the preheater, the top end of the smoke pipe is connected with the flue, and the bottom end of the smoke pipe is connected with a chimney. According to the low-nitrogen gas-steam boiler, the boiler body and the combustor are integrally designed, so that complicated structures such as a return smoke tube and a reversal chamber in a traditional boiler are omitted, the overall size of the boiler is greatly reduced, the weight is reduced accordingly, and the boiler is convenient to install and transport.

Description

TECHNICAL FIELD

[0001] The utility model relates to a boiler technical field, concretely relates to a low nitrogen gas steam boiler. BACKGROUND

[0002] The existing gas steam boiler is usually composed of a hearth, a first return flue, a second return flue, a shell, a back-draft chamber, a front / back smoke box, etc. This kind of boiler adopts diffusion combustion, and the flame heats the water in the boiler through hearth radiation and the first and second return flues to generate steam. Due to the long combustion flame, the boiler usually adopts a horizontal structure. However, this kind of structure has multiple defects:

[0003] Large volume and heavy weight: the overall size of the boiler is large, occupying a large space, and due to the complex structure, the weight is also relatively heavy.

[0004] Slow start: due to the large volume of the boiler, the time required for heating the entire system is long, resulting in slow start speed.

[0005] Low thermal efficiency: the thermal efficiency of the traditional gas steam boiler is not high, and part of the heat is lost in the combustion and heat transfer process.

[0006] High emission of flue gas nitrogen oxides: the emission of nitrogen oxides generated in the combustion process is high, which does not meet the modern environmental protection requirements. SUMMARY

[0007] The utility model aims at providing a low nitrogen gas steam boiler to solve the problems of large volume, heavy weight, slow start, low thermal efficiency, and high emission of flue gas nitrogen oxides raised in the above background.

[0008] To achieve the above-mentioned purpose, the utility model provides a low nitrogen gas steam boiler, which comprises a furnace body, the inside of the furnace body is provided with two groups of water pipes, the two groups of water pipes are respectively ascending pipes and descending pipes, the descending pipes are located at the periphery of the ascending pipes, one side of the ascending pipe is provided with a gas distributor, the gas distributor is installed with a burner towards one side of the ascending pipe, the other side of the gas distributor is installed with a mixer, the outside of the furnace body is provided with a preheater, one side of the furnace body is connected with a flue, a smoke pipe is vertically installed in the middle of the inside of the preheater, the top end of the smoke pipe is connected with the flue, and the bottom end of the smoke pipe is connected with a chimney.

[0009] As a preferred, the top of the furnace body is installed with an upper head, the inside of the upper head is installed with an upper partition, the bottom of the furnace body is installed with a lower head, the inside of the lower head is installed with a lower partition, the top end of the ascending pipe and the descending pipe all passes through the upper partition and communicates with the upper head, and the bottom end of the ascending pipe and the descending pipe all passes through the lower partition and communicates with the lower head.

[0010] Preferably, a water inlet pipe is connected to one side of the upper end cap, a steam outlet is installed at the top of the upper end cap, the water inlet pipe is connected to the upper water outlet pipe of the preheater through a pipeline, a water supply pipe is connected to the lower part of the preheater, a water supply valve and a water supply pump are installed on the water supply pipe, and a drain pipe is connected to the bottom of the lower end cap.

[0011] Preferably, the riser and the downcomer are isolated by a fire-resistant partition or a membrane wall.

[0012] Preferably, an inspection hole is provided in the middle of both the upper and lower end caps.

[0013] Preferably, a cavity is formed between the outer wall of the flue and the inner wall of the preheater shell, and the cavity is filled with boiler feedwater.

[0014] Preferably, one end of the mixer is provided with an air inlet and a natural gas inlet.

[0015] Preferably, the riser and downcomer are evenly arranged inside the furnace body.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0017] In this low-NOx gas-fired steam boiler, the boiler body and burner are designed as a single unit, eliminating the complex return flue pipes and combustion chambers found in traditional boilers. This significantly reduces the overall size and weight of the boiler, making it easier to install and transport.

[0018] Due to its compact size, the boiler significantly reduces the time required to heat the entire system, resulting in a much faster start-up speed and improved response and efficiency. Employing premixed combustion technology with the burner located inside the boiler body ensures more complete and uniform combustion, further enhancing efficiency. The boiler body is equipped with riser and downcomer pipes at intervals, creating a natural hydrodynamic circulation that increases the contact area between the heat source and water, improving heat exchange efficiency and further enhancing thermal efficiency. The premixed gas burns uniformly in the burner, and the resulting flue gas exchanges heat with the first water pipe group, scouring the outer wall of the pipe group and reducing flame temperature. This significantly reduces the synthesis and emission of nitrogen oxides, meeting modern environmental protection requirements.

[0019] Membrane walls or refractory baffles are used to isolate the riser and downcomer pipes, ensuring the downcomer pipes are not heated and guaranteeing the reliability of the hydrodynamic circulation. Waste heat from the boiler flue gas is absorbed by the preheater. The water in the preheater, heated by the waste heat, is then fed into the furnace through the boiler inlet pipe, serving as the water source for the first water pipe group. This increases the water source temperature and ensures steam production. Simultaneously, it lowers the flue gas temperature, reducing energy waste and improving energy efficiency. Attached Figure Description

[0020] Fig. 1This is a schematic diagram of the overall structure of this utility model;

[0021] Fig. 2 This is a schematic diagram of the internal structure of the furnace body in this utility model;

[0022] Fig. 3 This is a partial structural schematic diagram of the present invention;

[0023] The meanings of the labels in the diagram are as follows:

[0024] 1. Furnace body; 11. Ascension pipe; 12. Upper head; 121. Upper baffle; 122. Steam outlet; 123. Inspection hole; 13. Lower head; 131. Lower baffle; 14. Water inlet pipe; 15. Sewage pipe; 16. Downcomer; 17. Membrane wall; 2. Gas distributor; 21. Burner; 3. Mixer; 4. Flue; 5. Preheater; 51. Makeup water pipe; 52. Water outlet pipe; 53. Flue; 6. Chimney. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] This utility model provides a low-NOx gas-fired steam boiler, such as Figs. 1-3 As shown, the furnace includes a furnace body 1. Inside the furnace body 1 are two sets of water pipes: a riser pipe 11 and a downcomer pipe 16. The downcomer pipe 16 is located around the riser pipe 11. A gas distributor 2 is installed on one side of the riser pipe 11, and a burner 21 is installed on the side of the gas distributor 2 facing the riser pipe 11. A mixer 3 is installed on the other side of the gas distributor 2. A preheater 5 is installed on the outside of the furnace body 1. A flue 4 is connected to one side of the furnace body 1. A flue pipe 53 is vertically installed in the middle of the preheater 5. The top of the flue pipe 53 connects to the flue 4, and the bottom of the flue pipe 53 connects to a chimney 6. This ingenious design achieves efficient, low-NOx steam production. The riser pipe 11 and downcomer pipe 16 inside the furnace body 1 form an effective water circulation path. The downcomer pipe 16, located around the riser pipe 11, helps optimize heat transfer efficiency. The gas distributor 2 on one side of the riser pipe 11, in conjunction with the installed burner 21, ensures uniform and complete combustion of the fuel gas, improving combustion efficiency. Meanwhile, the mixer 3 on the other side of the gas distributor 2 facilitates the mixing of gas and air, further ensuring the stability and completeness of combustion.

[0027] A preheater 5 is arranged outside the furnace body 1. The internal intermediate vertically arranged flue 53 of the preheater 5 effectively utilizes the waste heat of the flue gas. The top end of the flue 53 is connected with the flue 4, and the bottom end is connected with the chimney 6, so that the flue gas can transfer the waste heat to the water in the preheater 5 when flowing through the flue 53, thereby increasing the temperature of the water source and providing more efficient heat energy input for steam production.

[0028] In this embodiment, the top of the furnace body 1 is provided with an upper head 12, the inner side of the upper head 12 is provided with an upper partition plate 121, the bottom of the furnace body 1 is provided with a lower head 13, the inner side of the lower head 13 is provided with a lower partition plate 131, the top ends of the riser 11 and the downcomer 16 pass through the upper partition plate 121 and communicate with the upper head 12, and the bottom ends of the riser 11 and the downcomer 16 pass through the lower partition plate 131 and communicate with the lower head 13. This design makes the water circulation system of the boiler more closed and efficient, helps to maintain the stability of the system pressure and temperature, and improves the operation efficiency and safety of the boiler.

[0029] Specifically, one side of the upper head 12 is connected with a water inlet pipe 14, the top of the upper head 12 is provided with a steam outlet 122, and the water inlet pipe 14 is connected with the upper water outlet pipe 52 of the preheater 5 through a pipeline. This design can make the preheated water directly enter the boiler system, improve the initial temperature of the water, and reduce the heating time. The lower part of the preheater 5 is connected with a water supplement pipe 51, the water supplement pipe 51 is provided with a water supplement valve and a water supplement pump, and the bottom of the lower head 13 is connected with a blowdown pipe 15. It ensures that the water quantity of the boiler system is sufficient and stable.

[0030] Further, the riser 11 and the downcomer 16 are isolated by a refractory partition plate or a membrane wall 17. This design can prevent the downcomer from being affected by too much heat, ensure the reliability of the water power circulation, and also help to improve the thermal efficiency and service life of the boiler.

[0031] Further, the middle parts of the upper head 12 and the lower head 13 are provided with inspection holes 123. This facilitates regular inspection and maintenance of the inside of the boiler, timely discovery and handling of potential problems, and ensures long-term stable operation of the boiler.

[0032] Further, the outer wall of the flue 53 and the inner wall of the shell of the preheater 5 form a cavity, and the cavity is filled with boiler water supplement. This design can make full use of the waste heat of the flue gas to heat the water supplement, improve the energy utilization efficiency, and also help to maintain the temperature stability of the preheater.

[0033] Further, one end of the mixer 3 is provided with an air inlet and a natural gas inlet. This design can make full use of the waste heat of the flue gas to heat the water supplement, improve the energy utilization efficiency, and also help to maintain the temperature stability of the preheater.

[0034] Further, the ascending pipes 11 and the descending pipes 16 are evenly arranged in the furnace body 1. This design can make the heat distribution in the boiler more uniform, improve the heat transfer efficiency, and also help to reduce the occurrence of local overheating and coking.

[0035] The low-nitrogen gas steam boiler in use mainly has the working principle based on the thermodynamic principle, the combustion principle and the waste heat recovery principle. The gas and the air are fully mixed in the mixer 3, then enter the gas distributor 2, and are uniformly combusted in the hearth through the burner 21 to release a large amount of heat. The heat is transmitted to the water in the ascending pipes 11 in the forms of radiation and convection, so that the water is gradually heated and boiled to generate steam. At the same time, the waste heat in the flue gas is recovered in the preheater 5 to heat the boiler feed water, thereby improving the energy utilization efficiency. Firstly, the boiler body is composed of the upper head 12, the lower head 13 and the first water pipe group (a group composed of the ascending pipes 11) and the second water pipe group (a group composed of the descending pipes 16) arranged between the upper head 12 and the lower head 13. The descending pipes 16 are located at the periphery of the ascending pipes 11 and are isolated from the ascending pipes 11 through the refractory partition plate or the membrane wall 17. The water source enters the upper head 12 through the boiler feed water pipe 14, then flows through each descending pipe 16 to enter the lower head 13. The water in the lower head 13 is heated from bottom to top through the ascending pipes 11, and high-temperature steam is formed in the upper head 12 after heat exchange with the hot stream.

[0036] The burner 21 is installed on the side of the gas distributor 2 facing the ascending pipes 11, and the surface of the burner 21 forms a combustion flame and generates a hot stream. The premixed gas (mixed in the mixer 3) enters the gas distributor 2 and then enters the burner 21 to burn. The combustion flame radiates to heat the surrounding water pipes and the flue gas generated by the burner, and the hot stream heats the water in the ascending pipes 11, greatly increasing the heat exchange area and the heat transfer efficiency. After heat exchange between the hot stream and the water in the ascending pipes 11, the flue gas is discharged from the flue gas outlet (the flue 4 connected to one side of the furnace body 1) and enters the preheater 5.

[0037] The smoke pipe 53 is vertically arranged in the middle of the preheater 5, the top end of the smoke pipe 53 is connected to the flue 4, and the bottom end is connected to the chimney 6. When the flue gas flows through the smoke pipe 53, the waste heat in the flue gas is transferred to the water (boiler feed water filled in the cavity) in the preheater 5. The preheated water is connected to the boiler feed water pipe 14 through the water outlet pipe 52 to enter the boiler system, thereby improving the initial temperature of the water and reducing the heating time.

[0038] The water supplement pipe 51 is provided with a water supplement valve and a water supplement pump to ensure that the water quantity of the boiler system is sufficient and stable. When the water level is below a certain value, the water supplement pump is started in time to supplement water. The middle parts of the upper head 12 and the lower head 13 are provided with inspection holes 123 for facilitating the periodic inspection and maintenance of the inside of the boiler. The blowdown pipe 15 is used for realizing the blowdown of the boiler.

[0039] The basic principle, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only preferred examples of the present application and are not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A low-nitrogen gas-steam boiler comprising a furnace (1), characterized in that: The inside of the furnace body (1) is provided with two groups of water pipes, which are the ascending pipe (11) and the descending pipe (16), the descending pipe (16) is located at the periphery of the ascending pipe (11), one side of the ascending pipe (11) is provided with a gas distributor (2), the gas distributor (2) is provided with a burner (21) on one side of the ascending pipe (11), the other side of the gas distributor (2) is provided with a mixer (3), the outside of the furnace body (1) is provided with a preheater (5), one side of the furnace body (1) is connected with a flue (4), the inside of the preheater (5) is vertically provided with a smoke pipe (53) in the middle, the top end of the smoke pipe (53) is connected with the flue (4), the bottom end of the smoke pipe (53) is connected with a chimney (6).

2. The low-nitrogen gas-steam boiler according to claim 1, characterized in that: The top of the furnace body (1) is provided with an upper head (12), the inside of the upper head (12) is provided with an upper baffle (121), the bottom of the furnace body (1) is provided with a lower head (13), the inside of the lower head (13) is provided with a lower baffle (131), the top end of the ascending pipe (11) and the descending pipe (16) penetrates the upper baffle (121) and communicates with the upper head (12), the bottom end of the ascending pipe (11) and the descending pipe (16) penetrates the lower baffle (131) and communicates with the lower head (13).

3. The low NOx gas and steam fired boiler of claim 2, wherein: One side of the upper head (12) is connected with a water inlet pipe (14), the top of the upper head (12) is provided with a steam outlet (122), the water inlet pipe (14) is connected with the upper water outlet pipe (52) of the preheater (5) through a pipeline, the lower part of the preheater (5) is connected with a water supplement pipe (51), the water supplement pipe (51) is provided with a water supplement valve and a water supplement pump, the bottom of the lower head (13) is connected with a blowdown pipe (15).

4. The low NOx gas and steam fired boiler of claim 1, wherein: The ascending pipe (11) and the descending pipe (16) are isolated by a refractory baffle or a membrane wall (17).

5. The low NOx gas and steam fired boiler of claim 2, wherein: The middle part of the upper head (12) and the lower head (13) is provided with an inspection hole (123).

6. The low NOx gas and steam fired boiler of claim 1, wherein: The outer wall of the smoke pipe (53) and the inner wall of the shell of the preheater (5) form a cavity, which is filled with boiler water.

7. The low NOx gas and steam fired boiler of claim 1, wherein: One end of the mixer (3) is provided with an air inlet and a natural gas inlet.

8. The low NOx gas and steam fired boiler of claim 1, wherein: The ascending pipe (11) and the descending pipe (16) are uniformly arranged in the furnace body (1).

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