A low-nitrogen burner device for a circulating fluidized bed boiler

Abstract

The utility model relates to the technical field of fluidized bed boiler, especially a low nitrogen combustor device for circulating fluidized bed boiler, including combustor main part, the combustor main part is box -shaped, the combustor main part inside has the transverse partition, the partition divides the combustor into gas pressure equalizing chamber and combustion gas chamber, the top of combustor main part is provided with multiple rows of injection pipe, wherein the injection pipe of the nth row is the gas injection pipe communicated with gas pressure equalizing chamber, the injection pipe of the nth-1 row is the combustion gas injection pipe communicated with combustion gas chamber, wherein n is the positive integer not less than 2, gas pressure equalizing chamber and combustion gas chamber are connected with gas distribution system and combustion gas supply system respectively. The combustor device changes the form of common nozzle type combustor, can provide uniform primary combustion flame, primary combustion zone temperature is balanced, avoids the local temperature excessively high caused by nozzle combustor flame concentration, reduces nitrogen gas oxidation and forms NOX.

Description

Technical Field

[0001] This utility model relates to the field of fluidized bed boiler technology, and in particular to a low-NOx burner device for a circulating fluidized bed boiler. Background Technology

[0002] In existing technologies, circulating fluidized bed (CFB) boilers emit significantly less NOx than traditional pulverized coal boilers and grate boilers. This is primarily because the bed temperature of a CFB boiler is typically around 870°C, while the combustion temperature of other boiler types exceeds 1100°C. At the lower bed temperature, nitrogen gas entering the boiler is less likely to be oxidized into NOx. Additionally, the stratified combustion within the CFB also contributes to the lower bed temperature.

[0003] Most circulating fluidized bed boilers use oil as primary fuel. Some equipment that uses gas as primary fuel suffers from uneven internal temperature due to the concentrated flame from nozzles, resulting in incomplete combustion of secondary fuels (such as pulverized coal) and increased environmental pressure. Utility Model Content

[0004] To address the aforementioned problems, this invention proposes a low-NOx burner device for a circulating fluidized bed boiler, the purpose of which is to enable the burner to provide a uniform primary combustion flame and a balanced temperature in the primary combustion zone.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A low-NOx burner device for a circulating fluidized bed boiler includes a burner body, which is box-shaped and has a horizontally placed partition inside the burner body, which divides the interior of the burner into a gas pressure equalization chamber and a gas combustion chamber. The burner body has multiple rows of nozzles on its top, wherein the nth row of nozzles is a gas nozzle connected to the gas equalization chamber, and the (n-1)th row of nozzles is an auxiliary gas nozzle connected to the auxiliary gas chamber, where n is a positive integer not less than 2. The gas equalization chamber and the gas-supporting chamber are respectively connected to the gas distribution system and the gas-supporting supply system.

[0006] Preferably, the gas equalization chamber is located below the gas combustion chamber.

[0007] Preferably, the position of the output end of the combustion-supporting nozzle is higher than the position of the output end of the combustion-supporting nozzle.

[0008] Preferably, the combustion-supporting nozzle and the combustion-supporting nozzle are arranged in an array.

[0009] Preferably, the combustion-supporting gas supply system includes two primary air supply pipes, which are installed on opposite sides of the combustion-supporting gas chamber and connected to the interior of the combustion-supporting gas chamber.

[0010] Preferably, the gas distribution system consists of a gas supply pipe, a primary gas distribution chamber, two primary gas distribution pipes, two secondary gas distribution chambers, and four secondary gas distribution pipes. The output end of the gas supply pipe is connected to the primary gas distribution chamber. Each secondary gas distribution chamber is connected to the primary gas distribution chamber through a primary gas distribution pipe. Each secondary gas distribution chamber is equipped with two secondary gas distribution pipes, and the output ends of the four secondary gas distribution pipes are respectively connected to the four sides of the gas equalization chamber.

[0011] The beneficial effects of using this utility model are: 1. The low-NOx burner device for circulating fluidized bed boilers proposed in this utility model changes the common nozzle burner to a heat spreader burner that is more suitable for gaseous primary fuel, which can provide a uniform primary combustion flame and a balanced temperature in the primary combustion zone.

[0012] 2. To ensure that the output gas pressure and flow rate of each gas nozzle in this burner unit are balanced, a dedicated gas distribution system is provided. The difference in output gas pressure and flow rate of each gas nozzle is less than 5%, and the primary fuel combustion flame temperature is uniform. This avoids excessively high local temperatures caused by concentrated flames in the nozzle burner and reduces the formation of NOx from nitrogen oxidation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a low-NOx burner unit used in a circulating fluidized bed boiler.

[0014] Figure 2 This is a top view of a low-NOx burner unit used in a circulating fluidized bed boiler.

[0015] Figure 3 This is a schematic diagram of a low-NOx burner device used in a circulating fluidized bed boiler, applied inside the boiler.

[0016] The reference numerals in the figures include: 10-Burner body, 11-Baffle plate, 12-Gas pressure equalization chamber, 13-Gas combustion chamber, 14-Gas combustion nozzle, 15-Gas nozzle; 20-Gas distribution system, 21-Gas supply pipe, 22-Primary gas distribution chamber, 23-Primary gas distribution pipe, 24-Secondary gas distribution chamber, 25-Secondary gas distribution pipe; 30 - Gas supply system; 31 - Primary air supply pipe; 40 - Fluidized bed boiler; 41 - Secondary fuel supply pipe; 42 - Secondary air supply pipe; 51 - Primary combustion zone, 52 - Secondary combustion zone. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this technical solution clearer, the following detailed description, in conjunction with specific embodiments, further illustrates this technical solution. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this technical solution.

[0018] To address the issues in existing fluidized bed boilers 40 that use burners adapted for fuel oil, which are nozzle-type burners unsuitable for use with natural gas as fuel, and whose concentrated flames cause uneven ignition of secondary fuels (such as pulverized coal), this embodiment proposes a low-NOx burner device for circulating fluidized bed boilers 40. This burner is suitable for use with natural gas as primary fuel, and its uniform flame can evenly ignite and combust secondary fuels, maximizing their calorific value.

[0019] like Figure 1 As shown, the low-NOx burner device for a circulating fluidized bed boiler 40 proposed in this embodiment includes a box-shaped burner body 10, which is made of hard alloy material and has excellent high-temperature resistance and oxidation resistance. A baffle 11 is provided in the middle of the horizontal direction inside the burner body 10, and the four edges of the baffle 11 are welded to the inner wall of the side plate of the burner body 10. The baffle 11 divides the interior of the burner body 10 into an upper combustion chamber 13 and a lower gas equalization chamber 12.

[0020] In some feasible embodiments, since the gas equalization chamber 12 needs to equalize the gas pressure, the baffle 11 is located in the upper middle part of the burner body 10, the volume of the gas equalization chamber 12 is increased, and the pressure equalization effect is better.

[0021] In this embodiment, five rows of holes are machined on the top surface of the burner body 10, with three holes in each row. The five rows of holes are arranged in an array. Each of the five rows of holes is welded with a combustion-supporting nozzle 14. The combustion-supporting nozzles 14 are all perpendicular to the top plate of the burner body 10. The interior of the combustion-supporting nozzles 14 is connected to the combustion-supporting chamber 13, thereby forming a five-row, three-panel array arrangement of combustion-supporting nozzles 14.

[0022] Then, a hole is machined in the middle of the four arrayed combustion-supporting nozzles 14 on the top plate of the burner body 10, and combined with... Figure 2 As shown, a total of 4 rows and 2 columns of array holes can be formed on the top plate of the burner body 10. From a top-down view, corresponding 4 rows and 2 columns of array holes are also machined on the partition plate 11. Eight gas nozzles 15 are passed through the holes on the top plate of the burner body 10. The lower ends of the gas nozzles 15 are welded to the edges of the holes on the partition plate 11, and the outer circumference of the gas nozzles 15 is welded to the burner body 10, forming a configuration as shown. Figure 1 and Figure 2The combustible body 10 shown is combined with the combustion-supporting nozzle 14 and the combustion nozzle 15. This type of combustible body 10 is a plate burner.

[0023] The aforementioned burner introduces oxidizing gas into the oxidizing chamber 13 and then into the gas equalization chamber 12. The gas is then ignited above the burner body 10. This burner device can provide flames at all gas nozzles 15, with a large flame area and low pressure at the outer edge of the flame.

[0024] like Figure 3 As shown, when this burner device is used in a circulating fluidized bed boiler 40, the combustion chamber 13 is connected to the combustion chamber supply system 30, and the gas equalization chamber 12 is connected to the gas distribution system 20. The combustion chamber supply system 30 supplies high-temperature primary gas after the flue gas of the circulating fluidized bed boiler 40 has undergone heat exchange. The gas supply system 20 preferably supplies activated ammonia, which refers to the mixed gas formed by igniting activated ammonia with Brown gas.

[0025] In this embodiment, the gas-supporting supply system 30 includes two primary air supply pipes 31, which are connected to the gas-supporting chamber 13 on opposite sides to provide primary air to the gas-supporting chamber 13.

[0026] The fluidized bed boiler 40 has a secondary fuel supply pipe 41 and a secondary air supply pipe 42 located at the furnace bed. The secondary fuel supply pipe 41 supplies pulverized coal, and the secondary air supply pipe 42 supplies combustion-supporting gas. In this embodiment, the burner device is located at the lower part of the fluidized bed boiler 40. The burner ignites the combustion gas, and the primary air assists in the combustion, forming a primary combustion zone 51 at the upper part of the burner device. The pulverized coal and combustion-supporting gas blown in by the secondary fuel supply pipe 41 and the secondary air supply pipe 42 are ignited by the high temperature of the primary combustion zone 51 after entering the furnace bed, forming a secondary combustion zone 52 in the furnace bed. Since this burner device is a plate burner, it can provide a uniform flame. Therefore, the heat in the primary combustion zone 51 is relatively uniform in the horizontal direction, and the pulverized coal entering the furnace bed is fully burned and releases heat. The secondary combustion zone 52 maintains an appropriate temperature, which can prevent the pulverized coal from charring and ensure that the pulverized coal is completely burned. In addition, since a primary combustion zone 51 and a secondary combustion zone 52 are formed inside the fluidized bed boiler 40, that is, segmented combustion is formed inside the fluidized bed boiler 40, it is beneficial to control the furnace bed temperature.

[0027] The cyclone separator, material return equipment, and flue gas treatment equipment in the fluidized bed boiler 40 are existing technologies and will not be described in detail. The material return equipment can be connected to the secondary combustion zone 52.

[0028] Combination Figure 1 and Figure 2As shown, in order to supply gas to the gas equalization chamber 12 and to ensure that each gas nozzle 15 sprays gas at equal pressure, the gas distribution system 20 in this embodiment uses a multi-directional gas supply technology to the gas equalization chamber 12.

[0029] Specifically, the gas distribution system 20 consists of a gas supply pipe 21, a primary gas distribution chamber 22, two primary gas distribution pipes 23, two secondary gas distribution chambers 24, and four secondary gas distribution pipes 25. The output end of the gas supply pipe 21 is connected to the primary gas distribution chamber 22. Each secondary gas distribution chamber 24 is connected to the primary gas distribution chamber 22 through a primary gas distribution pipe 23. Each secondary gas distribution chamber 24 is equipped with two secondary gas distribution pipes 25, and the output ends of the four secondary gas distribution pipes 25 are respectively connected to the four sides of the gas equalization chamber 12.

[0030] In this embodiment, the gas distribution system 20 adopts a 1-2-4 gas distribution scheme. The gas pressure and flow rate delivered to the gas equalization chamber 12 by each secondary gas distribution pipe 25 are basically the same, and the gas pressure and flow rate output by the gas nozzles 15 are also basically the same. The flame height formed by each gas nozzle 15 is consistent. Its direct advantage is that it can provide a uniform temperature range in the primary combustion zone 51 within the fluidized bed boiler 40, avoiding flame concentration. The difference in gas pressure and flow rate output by each gas nozzle 15 is less than 5%, and the primary fuel combustion flame temperature is average, avoiding excessively high local temperatures caused by concentrated flames in the nozzle burners, and reducing the formation of NOx from nitrogen oxidation.

[0031] It should be noted that, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. At the same time, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0032] The above content is only a preferred embodiment of this utility model. For those skilled in the art, many changes can be made in the specific implementation and application scope based on the ideas of this technical content. As long as these changes do not depart from the concept of this utility model, they all fall within the protection scope of this patent.

Claims

1. A low-NOx burner device for a circulating fluidized bed boiler, characterized in that: It includes a burner body, which is box-shaped, and has a horizontally placed partition inside the burner body, which divides the interior of the burner into a gas equalization chamber and a combustion-supporting chamber; The burner body has multiple rows of nozzles on its top, wherein the nth row of nozzles is a gas nozzle connected to the gas equalization chamber, and the (n-1)th row of nozzles is an auxiliary gas nozzle connected to the auxiliary gas chamber, where n is a positive integer not less than 2. The gas equalization chamber and the gas-supporting chamber are respectively connected to the gas distribution system and the gas-supporting supply system.

2. The low-NOx burner device for a circulating fluidized bed boiler according to claim 1, characterized in that: The gas equalization chamber is located below the gas-supporting chamber.

3. The low-NOx burner device for a circulating fluidized bed boiler according to claim 1, characterized in that: The position of the output end of the combustion-supporting nozzle is higher than the position of the output end of the gas nozzle.

4. The low-NOx burner device for a circulating fluidized bed boiler according to claim 1, characterized in that: The combustion-supporting nozzles and the combustion-supporting nozzles are arranged in an array.

5. The low-NOx burner device for a circulating fluidized bed boiler according to claim 1, characterized in that: The combustion-supporting gas supply system includes two primary air supply pipes, which are installed on opposite sides of the combustion-supporting gas chamber and connected to the interior of the combustion-supporting gas chamber.

6. The low-NOx burner device for a circulating fluidized bed boiler according to any one of claims 1-5, characterized in that: The gas distribution system consists of a gas supply pipe, a primary gas distribution chamber, two primary gas distribution pipes, two secondary gas distribution chambers, and four secondary gas distribution pipes. The output end of the gas supply pipe is connected to the primary gas distribution chamber. Each secondary gas distribution chamber is connected to the primary gas distribution chamber through a primary gas distribution pipe. Each secondary gas distribution chamber is equipped with two secondary gas distribution pipes, and the output ends of the four secondary gas distribution pipes are respectively connected to the four sides of the gas equalization chamber.

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