SNCR denitration spray gun prevents heated surface from corroding pipe

Abstract

The utility model relates to SNCR flue gas denitration technical field, and disclose a kind of SNCR denitration lance is prevented to be heated surface corrosion pipe, comprising: denitration lance pipe, multiple heat-resistant stainless steel dowel, anticorrosive medium seepage ring;The denitration lance pipe is installed on cyclone inlet flue gas cooling film type wall seal fin;The anticorrosive medium seepage ring is welded and installed in the lower half of denitration lance pipe flue gas side.The utility model is equipped with an anti-seepage ring in the lower half of denitration lance pipe, can effectively avoid in denitration lance mouth scale blockage and other working conditions, urea solution from the gap between denitration lance pipe and wear-resistant refractory material seeps into the risk of heated surface pipe, to thoroughly avoid urea solution and its by-product under high temperature environment to the corrosion degradation problem of denitration lance mouth periphery heated surface pipe.

Description

Technical Field

[0001] This utility model relates to the field of SNCR flue gas denitrification technology, and more specifically to a heat-resistant sleeve for an SNCR denitrification spray gun. Background Technology

[0002] A circulating fluidized bed boiler mainly consists of a combustion chamber, a gas-solid separator, and a material return system. Its working principle is based on fluidized bed combustion technology, the core of which lies in suspending and intensely mixing fuel particles through a high-speed airflow. The flue gas flow path is mainly as follows: combustion chamber → cyclone separator inlet flue → cyclone separator → separator outlet flue → tail flue → flue gas dust removal and desulfurization system → chimney.

[0003] SNCR, short for Selective Non-Catalytic Reduction, refers to the process of reducing nitrogen oxides (NOx) in flue gas to harmless nitrogen and water within a suitable temperature window for denitrification reactions, without the aid of a catalyst. This technology typically uses ammonia, urea, or hydrocyanic acid injected into the furnace as the reducing agent to reduce NOx. The reducing agent reacts only with NOx in the flue gas and generally does not react with oxygen. Because this technology does not use a catalyst, it is called Selective Non-Catalytic Reduction (SNCR). Since this process does not use a catalyst, the reducing agent must be added in a high-temperature zone. The reducing agent is injected into a region with a temperature of 850-1100℃, where it rapidly decomposes into NH3, which reacts with NOx in the flue gas to produce N2 and water.

[0004] The boiler used in the thermal power plant is a DG1025 / 17.4-Ⅱ18 type circulating fluidized bed boiler, which is equipped with three steam-cooled cyclone separators. The inlet flue of the cyclone separator connects the flue gas outlet of the combustion chamber to the cyclone separator, forming an airtight flue gas passage. Both the inlet flue of the cyclone separator and the cyclone separator body are clad with steam-cooled membrane walls. Both are lined with wear-resistant and refractory materials on the flue gas side.

[0005] To achieve environmentally compliant emissions, a new SNCR flue gas denitrification system was added. A 10-20% diluted urea solution was used as the reducing agent. The reducing agent was injected through denitrification nozzles positioned on both sides of the cyclone separator inlet flue to achieve flue gas denitrification. To prevent the atomizing nozzles of the denitrification nozzles from being directly exposed to the high-speed flue gas in the cyclone separator inlet flue and experiencing erosion and wear, the denitrification nozzles were fitted with wear-resistant and corrosion-resistant sleeves. Duck-claw pins were installed on the outside of the sleeves for applying wear-resistant and refractory material to prevent erosion and wear from the flue gas.

[0006] During the operation of the SNCR denitrification system, due to various reasons such as scaling and blockage at the denitrification nozzle, urea solution can seep from the gap between the denitrification nozzle sleeve and the refractory material into the outer surface of the steam-cooled film wall heating surface tube of the cyclone separator inlet flue, causing chemical and electrochemical corrosion. This results in thinning of the wall thickness of the steam-cooled film wall heating surface tube, creating a risk of leakage and tube rupture. Utility Model Content

[0007] In order to overcome the above-mentioned defects of the prior art, the present invention provides a heat-resistant surface corrosion sleeve for SNCR denitrification spray gun to solve the problems existing in the background art.

[0008] This utility model provides the following technical solution: a heat-resistant surface corrosion protection sleeve for an SNCR denitrification spray gun, comprising: a denitrification spray gun sleeve, multiple heat-resistant stainless steel pins, and a corrosion-resistant medium seepage ring. The denitrification spray gun sleeve is installed on the steam-cooled membrane wall sealing fin of the inlet flue of the cyclone separator. The anti-corrosion medium seepage ring is welded and installed on the lower half of the flue gas side of the denitrification spray gun sleeve; Multiple heat-resistant stainless steel pins are spot-welded to the outside of the denitrification spray gun sleeve, both sides of the anti-corrosion medium seepage ring, and the flue gas side of the steam-cooled film wall sealing fin, respectively, as anchors to improve the integrity and adhesion of the wear-resistant and refractory materials.

[0009] As a further embodiment of this invention, the anti-corrosion medium seepage ring is made of 310SS material.

[0010] As a further embodiment of this invention, the anti-corrosion medium seepage ring has a semi-circular structure and is installed in the lower half of the denitrification spray gun sleeve. This prevents the reducing agent from seeping into the outer wall of the flue gas side of the heated surface tube through the gap between the denitrification spray gun sleeve and the wear-resistant refractory material under conditions such as scaling and clogging at the denitrification spray gun nozzle. The resulting reducing products then corrode the heated surface of the steam-cooled film wall.

[0011] As a further embodiment of this invention, the semi-annular structure is vertically welded to the lower half of the flue gas side of the denitrification spray gun sleeve to form a physical barrier.

[0012] As a further embodiment of this utility model, the non-flue gas side portion of the denitrification spray gun sleeve is 550mm long, which is used to fix and seal with the denitrification spray gun, and to supply compressed air through this side. The flue gas side section is 200mm long and is used for spot welding heat-resistant stainless steel pins and laying wear-resistant and fire-resistant materials.

[0013] As a further embodiment of this invention, the centerline of the denitrification spray gun sleeve coincides with the centerline of the denitrification spray gun.

[0014] As a further embodiment of this utility model, the connection between the denitrification spray gun sleeve and the cyclone separator inlet flue gas-cooled film wall sealing fin is fixed by welding.

[0015] As a further improvement of this invention, an anti-wear structure can be detachably provided on the windward side of the denitrification spray gun sleeve.

[0016] As a further embodiment of this invention, the cross-section of the wear-resistant structure is V-shaped.

[0017] As a further embodiment of this invention, the pointed tip of the anti-wear structure faces the direction of the flue gas flow, and is used to divert and block the dust-laden flue gas from directly scouring the denitrification spray gun sleeve.

[0018] The technical effects and advantages of this utility model are as follows: By adding an anti-seepage ring to the lower half of the denitrification spray gun sleeve, this utility model can effectively avoid the risk of urea solution seeping into the heated surface tube from the gap between the denitrification spray gun sleeve and the wear-resistant refractory material under conditions such as scaling and blockage at the denitrification spray gun nozzle. Thus, it completely avoids the corrosion and deterioration problem of the heated surface tube around the denitrification spray gun nozzle caused by urea solution and its by-products under high temperature environment, and improves the operational safety and reliability of the pressure-bearing components of the inlet flue of the cyclone separator in the circulating fluidized bed boiler using SNCR denitrification process. Attached Figure Description

[0019] Figure 1 This is a cross-sectional structural diagram of the present invention.

[0020] Figure 2 This is the front view of the present invention.

[0021] The attached diagram is labeled as follows: 1. Denitrification spray gun sleeve; 2. Heat-resistant stainless steel pin; 3. Corrosion-resistant medium seepage ring. Detailed Implementation

[0022] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. This utility model is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0023] Reference Figures 1-2 This utility model provides a heat-resistant anti-corrosion sleeve for the SNCR denitrification spray gun arranged in the inlet flue area of ​​the cyclone separator in a circulating fluidized bed boiler, including a denitrification spray gun sleeve 1, a heat-resistant stainless steel pin 2, and an anti-corrosion medium seepage ring 3.

[0024] The denitrification spray gun sleeve 1 is installed on both sides of the inlet flue of the cyclone separator in the circulating fluidized bed boiler. After spot welding heat-resistant stainless steel pins 2 to the outside, wear-resistant and refractory materials are laid to prevent the denitrification spray gun from being eroded and worn by the high-temperature flue gas with high dust content.

[0025] The anti-corrosion medium seepage ring 3 is welded and installed on the lower half of the flue gas side of the denitrification spray gun sleeve 1.

[0026] The denitrification spray gun sleeve 1 is made of 310SS steel, with specifications of φ76×4.5mm and L=750mm. It is fixed to the steam-cooled film wall sealing fins of the cyclone separator inlet flue by welding, installed perpendicular to the steam-cooled film wall sealing fins. The length of the flue gas side is 200mm, and the length of the non-flue gas side is 550mm. On the flue gas side, heat-resistant stainless steel pins 2 are spot-welded, and then wear-resistant and refractory material is laid to prevent erosion and wear of the denitrification spray gun head. The non-flue gas side is used for fixing and sealing with the denitrification spray gun sleeve 1. Compressed air is supplied between the denitrification spray gun sleeve 1 and the denitrification spray gun for cooling the denitrification spray gun.

[0027] The heat-resistant stainless steel pins 2 are fixed to the outside of the denitrification spray gun sleeve 1, both sides of the anti-corrosion medium seepage ring 3, and the flue gas side of the steam-cooled film wall sealing fins by spot welding. They serve as anchors to improve the integrity and adhesion of the wear-resistant and refractory materials.

[0028] The anti-corrosion medium seepage ring 3 is made of 310SS and is semi-circular. It is installed perpendicular to the denitrification spray gun sleeve 1 by welding. It is installed in the lower half of the denitrification spray gun sleeve 1. It serves to prevent the reducing agent from seeping into the outer wall of the flue gas side of the heated surface tube through the gap between the denitrification spray gun sleeve 1 and the wear-resistant refractory material under operating conditions such as scaling and clogging at the denitrification spray gun nozzle, and the resulting reducing products from corroding the heat-receiving surface of the steam-cooled film wall.

[0029] The lower half of the denitrification spray gun sleeve 1 is vertically installed with an anti-corrosion medium seepage ring 3. This effectively prevents the reducing agent from seeping from between the denitrification spray gun sleeve 1 and the wear-resistant refractory material into the outer wall of the flue gas side of the steam-cooled film wall heating surface under conditions such as scaling and clogging of the denitrification spray gun nozzle. This completely eliminates the risk of corrosion of the steam-cooled film wall heating surface tube by corrosive media.

[0030] Therefore, by adding an anti-seepage ring to the lower half of the denitrification spray gun sleeve 1, the risk of urea solution seeping into the heated surface tube from the gap between the denitrification spray gun sleeve 1 and the wear-resistant refractory material can be effectively avoided under conditions such as scaling and clogging at the denitrification spray gun nozzle. This completely avoids the corrosion and deterioration of the heated surface tube around the denitrification spray gun nozzle caused by urea solution and its byproducts under high temperature conditions, and improves the operational safety and reliability of the pressure-bearing components of the inlet flue of the cyclone separator in the circulating fluidized bed boiler using SNCR denitrification technology.

[0031] Furthermore, an anti-wear structure can be detachably installed on the windward side of the denitrification spray gun sleeve 1.

[0032] Specifically, the cross-section of the wear-resistant structure is V-shaped, with the pointed tip of the wear-resistant structure facing the direction of flue gas flow, which is used to divert and block the dust-laden flue gas from directly scouring the denitrification spray gun sleeve 1.

[0033] By using materials with better wear resistance (such as ceramics or special wear-resistant steel), when wear occurs, only this component needs to be replaced instead of the entire denitrification spray gun sleeve 1, which greatly reduces maintenance costs and time and improves the maintainability of the equipment.

[0034] Finally, the following points should be noted: In the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change. The electronic components and modules used in this utility model can all be parts that are commonly used in the market and can achieve the specific functions in this case. The specific models and sizes can be selected and adjusted according to actual needs. The accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

Claims

1. A heat-resistant sleeve for an SNCR denitrification spray gun, characterized in that, include: Denitrification spray gun sleeve (1), multiple heat-resistant stainless steel pins (2), anti-corrosion medium seepage ring (3); The denitrification spray gun sleeve (1) is installed on the steam-cooled film wall sealing fin of the inlet flue of the cyclone separator; The anti-corrosion medium seepage ring (3) is welded and installed on the lower half of the flue gas side of the denitrification spray gun sleeve (1); Multiple heat-resistant stainless steel pins (2) are fixed by spot welding to the outside of the denitrification spray gun sleeve (1), both sides of the anti-corrosion medium seepage ring (3), and the flue gas side of the gas-cooled film wall sealing fin.

2. The SNCR denitrification spray gun heat-resistant surface corrosion protection sleeve according to claim 1, characterized in that: The material of the anti-corrosion medium seepage ring (3) is 310SS.

3. The SNCR denitrification spray gun heat-resistant surface corrosion protection sleeve according to claim 2, characterized in that: The anti-corrosion medium seepage ring (3) has a semi-circular structure.

4. The anti-corrosion sleeve for the heated surface of an SNCR denitrification spray gun according to claim 3, characterized in that: The semi-annular structure is vertically welded to the lower half of the flue gas side of the denitrification spray gun sleeve (1) to form a physical barrier.

5. The anti-corrosion sleeve for the heated surface of an SNCR denitrification spray gun according to claim 1, characterized in that: The non-flue gas side portion of the denitrification spray gun sleeve (1) is 550 mm long and is used to fix and seal with the denitrification spray gun, and to supply compressed air through this side. The flue gas side section is 200mm long and is used for spot welding heat-resistant stainless steel pins (2) and for laying wear-resistant and fire-resistant materials.

6. The anti-corrosion sleeve for the heated surface of an SNCR denitrification spray gun according to claim 1, characterized in that: The centerline of the denitrification spray gun sleeve (1) coincides with the centerline of the denitrification spray gun.

7. The SNCR denitrification spray gun heat-resistant surface corrosion protection sleeve according to claim 1, characterized in that: The denitrification spray gun sleeve (1) is connected to the steam-cooled film wall sealing fin of the cyclone separator inlet flue by welding.

8. The anti-corrosion sleeve for the heated surface of an SNCR denitrification spray gun according to claim 1, characterized in that: On the windward side of the denitrification spray gun sleeve (1), an anti-wear structure can also be detachably provided.

9. The SNCR denitrification spray gun heat-resistant surface corrosion protection sleeve according to claim 8, characterized in that: The cross-section of the wear-resistant structure is V-shaped.

10. The SNCR denitrification spray gun heat-resistant surface corrosion protection sleeve according to claim 9, characterized in that: The pointed tip of the anti-wear structure faces the direction of flue gas flow and is used to divert and block the dust-laden flue gas from directly scouring the denitrification spray gun sleeve (1).

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