A serpentine tube type ammonia injection device applied to a heating furnace

Abstract

The utility model belongs to the SCR denitration technical field, has solved the number of feed mother pipe in prior art to be more, the hole on the boiler is more complex, is easy to appear the collision, has increased the construction cost, the utility model provides a serpentine pipe type ammonia injection device for heating furnace, including in the flue matrix distribution several groups of serpentine pipe type module, several groups serpentine pipe type template divide the flue cross section into equal number of several subareas, and each group serpentine pipe type template can control ammonia injection amount individually, this device simple structure, processing and manufacturing cost are lower, the number of feed mother pipe is less, the number of hole on the boiler wallboard is less, reduces the risk of collision with boiler wallboard stiffener, in addition serpentine pipe type module can better the rectangular flue cross section carries out the regionalization design, can control the ammonia injection amount through adjusting the opening of each area corresponding manual regulating valve, and then makes up the defect that the flue gas flow field is not good, reduces the denitration efficiency.

Description

Technical Field

[0001] This utility model relates to the field of SCR denitrification technology, specifically to a serpentine tube ammonia injection device applied to a heating furnace. Background Technology

[0002] Research on flue gas denitrification technology for industrial heating furnaces in China started relatively late. Previously operational furnaces, such as the widely used ethylene cracking furnace, generally lacked flue gas denitrification facilities, relying mostly on low-NOx burners to reduce NOx emissions. However, considering fuel utilization and stable combustion, low-NOx burners can only reduce NOx concentrations to 80-100 mg / Nm³. 3 The level is far from the latest national ultra-low emission standard (50mg / Nm³). 3 Or 30mg / Nm 3 There is still a certain distance. Furthermore, the flue gas from the heating furnace has its own unique characteristics compared to the flue gas from conventional thermal power plant boilers: 1. The flue gas velocity in the heating furnace is particularly low. Denitrification is generally done in-furnace, and the cross-section of the flue gas duct at the ammonia injection location is generally rectangular, meaning the length-to-width ratio is particularly large. This increases the difficulty of uniformly designing the ammonia injection device; 2. There are many vertical reinforcing ribs on the heating furnace wall, requiring the ammonia injection device's feed pipe to have openings in the furnace wall. This necessitates minimizing the number of ammonia injection feed pipe openings to avoid collisions; 3. The NOx concentration in the heating furnace flue gas is low, increasing the difficulty for the reducing agent NH3 to capture NOx in the flue gas. Therefore, the ammonia injection device needs to have strong uniformity; 4. The heating furnace generally operates periodically (such as during coke removal operations), or during raw material switching or load adjustments. The NOx concentration in the flue gas fluctuates significantly with changes in process conditions, which may affect the stable operation of the denitrification system.

[0003] Traditional zoned ammonia injection grids consist of a feed header connected to a pair of injection pipes, i.e., the injection pipes are H-shaped. To achieve a uniform ammonia injection effect, multiple feed and injection modules are usually set up. This results in a large number of feed headers, more complex openings on the boiler, and a high risk of collisions. It also increases construction costs.

[0004] Therefore, given the current operating conditions of the heating furnace flue gas, adopting a practical ammonia injection device to reduce nitrogen oxide concentration and ammonia escape has become an urgent task for various refining and chemical companies.

[0005] In view of this, this patent proposes a serpentine tube ammonia injection device for use in heating furnaces. Utility Model Content

[0006] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this disclosure provides a serpentine tube ammonia injection device for use in a heating furnace.

[0007] To achieve the aforementioned objective, this utility model provides a serpentine tube ammonia injection device for a heating furnace, comprising several groups of serpentine tube modules arranged in a matrix within a flue. The several groups of serpentine tube modules divide the flue cross-section into several equal sections, and each group of serpentine tube modules can individually control the amount of ammonia injected.

[0008] Optionally, the serpentine tube module includes a feed main pipe, a manual regulating valve, a serpentine spray pipe, and nozzles. The manual regulating valve is disposed on the feed main pipe, the serpentine spray pipe is connected to the feed main pipe, and multiple nozzles are disposed on the serpentine spray pipe.

[0009] Optionally, the manual regulating valve is welded to or flanged to the feed header.

[0010] Optionally, the lateral distance and longitudinal distance between two adjacent nozzles on the serpentine spray pipe are A and B, respectively, and A / B is between [0.05] and [0.05].

[0011] Optionally, the nozzles in adjacent groups of serpentine tube modules are spaced at the same distance.

[0012] Optionally, the serpentine spray pipe includes three spray pipes and four 90° bends connecting the three spray pipes, with four or six nozzles provided on each spray pipe.

[0013] The technical solution provided in this disclosure has the following advantages compared with the prior art: (1) Compared with the traditional single injection pipe or H-type injection pipe, the serpentine tube type ammonia injection device greatly reduces the number of feed main pipes, that is, reduces the number of openings on the boiler wall panel and reduces the amount of construction work. (2) The serpentine tube design allows for better regionalization of the rectangular flue section. The amount of ammonia injected in each region can be controlled by a manual adjustment valve, which compensates for the deviation in the NH3 / NOx molar ratio caused by poor flue gas flow field. (3) The serpentine tube ammonia injection device can adapt to flue sections with various length-to-width ratios, and the uniformity of ammonia injection is better than that of traditional longitudinal or H-type ammonia injection devices. (4) The ammonia injection device has a modular design, which makes it easy to process and manufacture, saving manufacturing costs. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of a serpentine tube ammonia injection device applied to a heating furnace in the flue according to an embodiment of the present utility model; Figure 2 This is a schematic diagram of a serpentine tube module according to an embodiment of the present utility model; Figure 3 According to the embodiments of this utility model Figure 1 A side view of a serpentine tube ammonia injection device used in a heating furnace.

[0016] Among them, 1. feed main pipe; 2. manual regulating valve; 3. serpentine spray pipe; 301. spray pipe; 302. elbow; 4. nozzle. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described in conjunction with 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 implementation methods obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0018] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should fall within the scope of the technical content disclosed in this utility model. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0019] like Figures 1 to 3 As shown, this embodiment provides a serpentine tube ammonia injection device for use in a heating furnace, including several groups of serpentine tube modules distributed in a matrix within the flue. The several groups of serpentine tube modules divide the flue cross section into several equal sections, and each group of serpentine tube modules can independently control the amount of ammonia injected.

[0020] According to the above implementation method, the serpentine tube module can regionalize the rectangular flue section. By adjusting the ammonia injection amount corresponding to each region, it can compensate for the defects of poor flue gas flow field and reduced denitrification efficiency.

[0021] In a relatively specific embodiment, the serpentine tube module includes a feed header 1, a manual regulating valve 2, a serpentine injection pipe 3, and nozzles 4. The manual regulating valve 2 is installed on the feed header 1, the serpentine injection pipe 3 is connected to the feed header 1, and multiple nozzles 4 are installed on the serpentine injection pipe 3. The amount of ammonia injected can be controlled by adjusting the opening of the manual regulating valve corresponding to each area. The fewer the number of feed headers 1 and the fewer the number of openings on the boiler wall panel, the lower the risk of collision with the boiler wall panel reinforcing ribs.

[0022] In a relatively specific embodiment, the manual regulating valve 2 is welded or flanged to the feed header 1.

[0023] In a relatively specific embodiment, the lateral distance and longitudinal distance between two adjacent nozzles 4 on the serpentine spray pipe 3 are A and B, respectively, and A / B is between 0.8 and 1.25.

[0024] In a relatively specific embodiment, the nozzles 4 in adjacent groups of serpentine tube modules are spaced at the same distance.

[0025] In a relatively specific embodiment, the serpentine spray pipe 3 includes three spray pipes 301 and four 90° bends 302 connecting the three spray pipes 301, and four or six nozzles 4 are provided on each spray pipe 301.

[0026] Specifically, in this embodiment, 20 sets of serpentine tube modules are arranged within the cross-sectional area of ​​the flue, in a 2-row, 10-column configuration, dividing the flue cross-section into 20 corresponding zones. The ammonia injection rate of each serpentine tube module can be adjusted by operating the manual regulating valve 2 within each module.

[0027] In this embodiment, the flue section is arranged in zones, which not only simplifies the number of feed headers and reduces the amount of work required to open holes in the boiler wall, but also simplifies processing and facilitates transportation. In addition, each feed header is equipped with a manual regulating valve, which allows for regional adjustment of the ammonia demand in each zone.

[0028] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A serpentine tube ammonia injection device for use in a heating furnace, characterized in that, It includes several groups of serpentine tube modules distributed in a matrix within the flue, which divide the flue cross-section into an equal number of partitions, and each group of serpentine tube modules can independently control the amount of ammonia injected.

2. The serpentine tube ammonia injection device for a heating furnace according to claim 1, characterized in that, The serpentine tube module includes a feed main pipe (1), a manual regulating valve (2), a serpentine jet pipe (3), and nozzles (4). The manual regulating valve (2) is installed on the feed main pipe (1), the serpentine jet pipe (3) is connected to the feed main pipe (1), and multiple nozzles (4) are installed on the serpentine jet pipe (3).

3. A serpentine tube ammonia injection device for a heating furnace according to claim 2, characterized in that, The manual regulating valve (2) is welded or flanged to the feed main pipe (1).

4. A serpentine tube ammonia injection device for a heating furnace according to claim 2, characterized in that, The lateral distance and longitudinal distance between two adjacent nozzles (4) on the serpentine spray pipe (3) are A and B, respectively, and A / B is between 0.8 and 1.

25.

5. A serpentine tube ammonia injection device for a heating furnace according to claim 2, characterized in that, The nozzles (4) in adjacent groups of serpentine tube modules are spaced at the same distance.

6. A serpentine tube ammonia injection device for a heating furnace according to claim 2, characterized in that, The serpentine spray pipe (3) includes three spray pipes (301) and four 90° bends (302) connecting the three spray pipes (301), and the nozzles (4) are provided in four or six on each of the spray pipes (301).

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