CN219083160U

CN219083160U - Arrangement structure for preventing SNCR (selective non-catalytic reduction) drip from corroding boiler water-cooled wall

Info

Publication number: CN219083160U
Application number: CN202223473029.0U
Authority: CN
Inventors: 肖勇; 马颖达; 蔡永祥; 任建华; 朱霞; 陈俊
Original assignee: Nantong Wanda Energy Power Technology Co ltd
Current assignee: Nantong Wanda Energy Power Technology Co ltd
Priority date: 2022-12-26
Filing date: 2022-12-26
Publication date: 2023-05-26
Anticipated expiration: 2032-12-26

Abstract

The utility model provides an arrangement structure for preventing SNCR (selective non-catalytic reduction) liquid drops from corroding a boiler water-cooled wall, which is characterized in that a plurality of spray gun mounting mechanisms are embedded and mounted in the water-cooled wall at the peripheral side of a vertical flue of a hearth, and the spray gun mounting mechanisms comprise: a pouring sealing box in the water-cooling wall and close to the inner side of the vertical flue of the hearth, a heat preservation sealing box on the other side in the water-cooling wall and connected with the pouring sealing box, an SNCR spray gun obliquely connected in the pouring sealing box and the heat preservation sealing box, and a lengthened water-cooling wall let pipe in the pouring sealing box and the heat preservation sealing box and bent away from a spray head of the SNCR spray gun; the spray head side of the SNCR spray gun is inclined downwards in the vertical flue of the hearth. According to the arrangement structure for preventing SNCR (selective non-catalytic reduction) liquid drops from corroding the water-cooled wall of the boiler, the SNCR spray gun is provided with the reasonable slight inclined angle, so that residual liquid drops of the spray head accessory gather and are converged into a hearth by means of self gravity, and backflow to a water-cooled wall pipe is avoided.

Description

Arrangement structure for preventing SNCR (selective non-catalytic reduction) drip from corroding boiler water-cooled wall

Technical Field

The utility model relates to the field of environment-friendly boilers, in particular to an arrangement structure for preventing SNCR (selective non-catalytic reduction) drip from corroding a water cooling wall of a boiler.

Background

According to the emission control standard of boiler flue gas NOx in China, the SNCR technology is one of the mainstream technologies for in-furnace denitration of the incineration power plant at present. SNCR technology, i.e. selective non-catalytic reduction technology, is to directly spray denitration agents such as urea, ammonia liquor and the like into a furnace in the range of 850-1100 ℃ of flue gas temperature, so as to reduce nitrogen oxides into nitrogen and water vapor. Because the denitration efficiency of the technology is greatly influenced by the contact area of the denitration agent and the nitrogen oxide, two to three layers of wall-type ejectors which are tens of in total are arranged around a vertical flue of the hearth according to the geometric dimensions of the section, the height and the like of the hearth in design, the denitration agent is distributed to each spray gun through a metering and distributing device, and finally the denitration agent is atomized through an atomizing medium (high-pressure steam or compressed air) and then sprayed into the hearth through the spray guns to perform denitration reaction.

In the practical application process, various reasons such as improper operation of operators, defects of a spray gun structure, insufficient pressure of an atomization medium, incomplete atomization of a denitration agent when an SNCR system is frequently started and stopped are often found, so that SNCR dropping liquid flows back to a water wall opening along a spray gun and drops along a water wall pipe. As is known, urea and ammonia liquor have stronger corrosiveness, and liquid drops can undergo chemical reaction when encountering a water wall pipe (material 20G) so as to cause the water wall pipe to burst and leak, thereby seriously affecting the safety and reliability of the boiler.

Disclosure of Invention

The utility model discloses an arrangement structure for preventing SNCR (selective non-catalytic reduction) drip from corroding a water wall of a boiler, which is used for solving the technical problem that SNCR drip corrodes the water wall pipe caused by that SNCR drip flows back to an opening of the water wall along a spray gun or drips down along the water wall pipe in the boiler for SNCR denitration in the background technology.

The technical scheme provided by the utility model is as follows: an arrangement structure for preventing SNCR (selective non-catalytic reduction) liquid drops from corroding a boiler water wall, which is characterized in that a plurality of spray gun mounting mechanisms are embedded in the water wall on the periphery of a vertical flue of a hearth, and the spray gun mounting mechanisms comprise: a pouring sealing box in the water-cooling wall and close to the inner side of the vertical flue of the hearth, a heat preservation sealing box on the other side in the water-cooling wall and connected with the pouring sealing box, an SNCR spray gun obliquely connected in the pouring sealing box and the heat preservation sealing box, and a lengthened water-cooling wall let pipe in the pouring sealing box and the heat preservation sealing box and bent away from a spray head of the SNCR spray gun; the spray head side of the SNCR spray gun is inclined downwards in the vertical flue of the hearth.

Furthermore, the pouring sealing box and the heat preservation sealing box are obliquely connected with a conical wall bushing, and the SNCR spray gun is detachably connected in the conical wall bushing through an outer end flange.

Further, one end of the conical wall bushing is provided with a conical opening, the conical opening is arranged in a vertical flue of the hearth, and a spray head of the SNCR spray gun is arranged in the conical opening.

Further, the included angle beta of the conical opening is 100-120 degrees, and the interval B between the center of the end part of the conical opening and the outer part of the pouring sealing box is 30mm.

Further, the included angle alpha between the central line of the SNCR spray gun and the horizontal line is 3-10 degrees.

Further, the distance A between the lower bending starting point of the lengthened water-cooled wall and the mounting hole of the SNCR spray gun is more than or equal to 500mm.

Further, refractory castable is paved in the casting sealing box, and the thickness C of the refractory castable is 70-100 mm.

Further, the heat-insulating sealing box is filled with heat-insulating cellucotton, and the thickness D of the heat-insulating cellucotton is 200-250 mm.

Compared with the prior art, the utility model has the beneficial effects that:

(1) The utility model prevents SNCR liquid drops from corroding the arrangement structure of the boiler water wall, separates the SNCR liquid drops from the water wall pipe by adopting multiple isolation measures, and avoids direct contact between the SNCR liquid drops and the water wall pipe, thereby greatly reducing the risk of corrosion and explosion of the water wall pipe.

(2) According to the arrangement structure for preventing SNCR liquid drops from corroding the water-cooled wall of the boiler, the SNCR spray gun is provided with a reasonable slight inclination angle, so that residual liquid drops of the spray head accessory gather and are converged into a hearth by means of self gravity, and backflow to the water-cooled wall pipe is avoided.

(3) According to the arrangement structure for preventing SNCR liquid drops from corroding the water-cooled wall of the boiler, the tail end of the conical wall bushing is provided with the conical opening, and a reasonable flaring angle is adopted, so that an atomization medium can be fully expanded at a spray head, the atomization effect of a denitration agent is improved, and the generation of SNCR liquid drops is reduced; meanwhile, the conical wall bushing and the casting sealing box are made of corrosion-resistant and high-temperature-resistant materials 316L, so that the service life of the structure is ensured.

Drawings

FIG. 1 is a schematic diagram of the overall structure of the SNCR drip corrosion prevention water wall arrangement of the present utility model;

FIG. 2 is an enlarged view of a portion of the utility model at I in FIG. 1;

FIG. 3 is an enlarged view of a portion of the utility model at II in FIG. 2.

The reference numerals are as follows: 1. the vertical flue of furnace, 2, extension formula water-cooled wall let pipe, 3, SNCR spray gun, 4, toper wall bushing, 5, pouring seal box, 6, refractory castable, 7, heat preservation seal box, 8, heat preservation cellocotton, 9, outer flange.

Detailed Description

The utility model will be described in further detail below with reference to the drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

As shown in fig. 1-3, the utility model is an arrangement structure for preventing SNCR drip from corroding a water-cooled wall of a boiler, a plurality of spray gun mounting mechanisms are embedded and mounted in the water-cooled wall at the 1-week side of a vertical flue of a hearth, and the spray gun mounting mechanisms comprise: a pouring seal box 5 in the water-cooled wall and close to the inner side of the vertical flue 1 of the hearth, a heat preservation seal box 7 on the other side in the water-cooled wall and connected with the pouring seal box 5, an SNCR spray gun 3 obliquely connected in the pouring seal box 5 and the heat preservation seal box 7, and an lengthened water-cooled wall let pipe 2 in the pouring seal box 5 and the heat preservation seal box 7 and bent away from the spray head of the SNCR spray gun 3; wherein the nozzle side of the SNCR lance 3 is inclined downwards in the furnace vertical flue 1.

In the embodiment, eighteen spray gun mounting mechanisms are arranged in three directions on the periphery of the vertical hearth flue 1 according to the temperature interval and the geometric dimension of the hearth in the vertical hearth flue.

Specifically, the included angle alpha between the central line of the SNCR spray gun 3 and the horizontal line is 3-10 degrees, so that residual drip near the SNCR spray head can be gathered and collected into the vertical flue 1 of the hearth by means of self gravity, and the residual drip is prevented from flowing back.

Specifically, a mounting hole site of the SNCR spray gun 3 is reserved on the water-cooled wall, and a conventional linear water-cooled wall pipe in the reserved hole site is bent to two sides to form an lengthened water-cooled wall let pipe 2 far away from a spray head of the SNCR spray gun 3.

Specifically, the distance A between the lower bending point of the lengthened water-cooled wall let pipe 2 and the mounting hole of the SNCR spray gun 3 is more than or equal to 500mm, so that the lengthened water-cooled wall let pipe 2 is far away from the spray head of the SNCR spray gun 3, and the backflow or penetration of the liquid drop from the mounting hole to the lengthened water-cooled wall let pipe 2 is avoided, and the lengthened water-cooled wall let pipe 2 corrodes the pipe explosion.

Specifically, the casting sealing box 5 is placed in the reserved hole, the casting sealing box 5 is sealed and welded on the inner side of the water-cooled wall, and the casting sealing box 5 is made of a corrosion-resistant and high-temperature-resistant material 316L so as to ensure the service life of the casting sealing box 5 in the vertical flue 1 of the hearth.

Specifically, the heat-preservation sealing box 7 is placed in a reserved hole site, the heat-preservation sealing box 7 is sealed and welded on the outer side of the water-cooled wall, the heat-preservation sealing box 7 is made of Q235B carbon structural steel, the cost is low, and the plasticity is high.

Furthermore, the pouring sealing box 5 and the heat preservation sealing box 7 are obliquely connected with the conical wall bushing 4, and the SNCR spray gun 3 is detachably connected in the conical wall bushing 4 through the outer end flange 9.

Specifically, sleeve mounting holes are formed in the pouring sealing box 5 and the heat-insulating sealing box 7, the conical wall bushing 4 is arranged in the sleeve mounting holes, and the joint of the conical wall bushing 4 and the heat-insulating sealing box 7 is sealed and welded.

Specifically, the tapered wall bushing 4 uses the corrosion-resistant and high temperature-resistant material 316L to ensure the service life of the tapered wall bushing 4.

Specifically, toper wall bushing 4 one end is equipped with the toper mouth, and the toper mouth is in furnace vertical flue 1, and the shower nozzle of SNCR spray gun 3 is in the toper mouth, can make the atomizing medium fully expand in the shower nozzle department of SNCR spray gun 3 through setting up the toper mouth, improves the atomization effect of denitration agent, reduces the production of SNCR dropping liquid.

Specifically, the included angle beta of the conical opening is 100-120 degrees, and the interval B between the center of the end part of the conical opening and the outside of the pouring sealing box 5 is 30mm.

Specifically, an outer end flange 9 is arranged at the outer end of the conical wall bushing 4, an outer end flange 9 is arranged at the rod part of the SNCR spray gun 3, and after the SNCR spray gun 3 is placed in the conical wall bushing 4, the two outer end flanges 9 are connected through screws and nuts, so that the SNCR spray gun 3 is fixed in the conical wall bushing 4.

Further, a refractory castable 6 is paved in the pouring sealing box 5, and the thickness C of the refractory castable 6 is 70-100 mm.

Specifically, by paving the refractory castable 6 in the casting sealing box 5, the heat conductivity coefficient of the vertical flue 1 of the hearth in the water-cooled wall can be effectively reduced, and the material has the properties of permeation resistance, corrosion resistance, impact resistance, wear resistance and the like, so that the structural performance is stronger, and the service life of equipment is prolonged.

Further, the heat-insulating sealing box 7 is internally filled with heat-insulating cellucotton 8, and the thickness D of the heat-insulating cellucotton 8 is 200-250 mm.

Specifically, through the heat preservation cellocotton 8 of filling in the heat preservation seal box 7, can effectually prevent that the temperature outside the water-cooling wall from letting the influence of pipe 2 to the extension water-cooling wall, guaranteed the extension water-cooling wall and let the effect of pipe 2.

Working principle: reserving a mounting hole site of the SNCR spray gun 3 on a water wall, bending a conventional linear water wall pipe in the reserved hole site to two sides of the pipe 2 which is far away from a lengthened water wall of a spray head of the SNCR spray gun 3, respectively filling refractory castable 6 and heat-insulating cellucotton 8 in a casting sealing box 5 and a heat-insulating sealing box 7, placing the casting sealing box 5 into the reserved hole site from the inner side of the water wall and sealing the water wall, placing the heat-insulating sealing box 7 into the reserved hole site from the inner side and sealing the water wall, placing a conical wall bushing 4 in the mounting hole site of the casting sealing box 5 and the heat-insulating sealing box 7, and sealing the outer sides of the conical wall bushing 4 and the heat-insulating sealing box 7; the SNCR lance 3 is placed into the tapered wall bushing 4 and the outer flange 9 is screwed.

Claims

1. An arrangement structure for preventing SNCR (selective non-catalytic reduction) liquid drops from corroding a water-cooled wall of a boiler is characterized in that a plurality of spray gun mounting mechanisms are embedded and mounted in the water-cooled wall on the periphery side of a vertical flue (1) of a hearth, and the spray gun mounting mechanisms comprise: a pouring sealing box (5) in the water-cooling wall and close to the inner side of the vertical flue (1) of the hearth, a heat preservation sealing box (7) connected with the pouring sealing box (5) at the other side in the water-cooling wall, SNCR spray guns (3) obliquely connected in the pouring sealing box (5) and the heat preservation sealing box (7), and an lengthened water-cooling wall let pipe (2) in the pouring sealing box (5) and the heat preservation sealing box (7) and bent away from the spray heads of the SNCR spray guns (3); the spray head side of the SNCR spray gun (3) is inclined downwards in the vertical hearth flue (1).

2. Arrangement structure for preventing SNCR drip from corroding boiler water wall according to claim 1, characterized in that the pouring sealing box (5) and the heat preservation sealing box (7) are connected with a conical wall bushing (4) in an inclined way, and the SNCR spray gun (3) is detachably connected in the conical wall bushing (4) through an outer end flange (9).

3. An arrangement structure for preventing SNCR drip from corroding a boiler water wall as claimed in claim 2, wherein one end of the conical wall bushing (4) is provided with a conical opening, the conical opening is arranged in the vertical flue (1) of the hearth, and the spray head of the SNCR spray gun (3) is arranged in the conical opening.

4. A structure for preventing SNCR drip from corroding the water-cooled wall of a boiler according to claim 3, wherein the included angle β of the conical opening is 100-120 °, and the interval B between the center of the end of the conical opening and the outside of the casting seal box (5) is 30mm.

5. An arrangement structure for preventing SNCR drip from corroding a boiler water wall as claimed in claim 1, wherein the included angle alpha between the central line of the SNCR spray gun (3) and the horizontal line is 3-10 degrees.

6. An arrangement structure for preventing SNCR drip from corroding a boiler water wall as set forth in claim 1, wherein the distance A between the lower bending point of the lengthened water wall let tube (2) and the mounting hole of the SNCR spray gun (3) is more than or equal to 500mm.

7. The arrangement structure for preventing SNCR (selective non-catalytic reduction) drip from corroding the water-cooled wall of a boiler as claimed in claim 1, wherein refractory castable (6) is paved in the pouring sealing box (5), and the thickness C of the refractory castable (6) is 70-100 mm.

8. The arrangement structure for preventing SNCR (selective non-catalytic reduction) drip from corroding the water-cooled wall of a boiler as claimed in claim 1, wherein the heat-insulating sealing box (7) is internally filled with heat-insulating cellucotton (8), and the thickness D of the heat-insulating cellucotton (8) is 200-250 mm.