CN202237748U - SNCR (selective non catalytic reduction) flue gas denitration device taking carbamide as reducing agent - Google Patents

Abstract

The utility model discloses an SNCR flue gas denitrification device using urea as a reducing agent. Including solid urea tank truck, hose, union, solid urea regulating valve, solid urea storage tank, solid urea feeder, compressed air main pipe, compressed air regulating valve, agitator, urea solution preparation tank, heater, industrial water main pipe , industrial water regulating valve, urea delivery pump, urea solution storage tank, urea injection pump, mixer, urea return regulating valve, pressurized industrial water regulating valve, industrial water pump, urea dilute solution regulating valve, atomizing steam regulating valve, mist Steam header, urea injection unit. When canning urea, it realizes automatic continuous feeding to ensure the concentration and uniformity of urea solution, and automatically adjusts the urea flow rate according to the NOx emission of the combustion equipment, so that the NOx emission of the combustion equipment is within the control range, and the denitrification effect is 60%; When the bagged urea is supplied, the urea solution preparation tank is manually put into the urea preparation tank, and the urea preparation is intermittent operation.

Description

A SNCR flue gas denitrification device using urea as a reducing agent

technical field

The utility model relates to a flue gas denitrification device, in particular to an SNCR flue gas denitrification device using urea as a reducing agent.

Background technique

In the field of flue gas denitrification, two methods, selective catalytic reduction (SCR) and non-selective catalytic reduction (SNCR), have been widely used. These two methods both use NH ₃ as a reducing agent to reduce NOx to harmless N ₂ and H ₂ O. The SNCR method is to spray a reducing agent aqueous solution such as ammonia or urea into the flue gas at 850~1150°C to realize the reduction reaction of NOx. Because it basically does not occupy the space of combustion equipment, the transformation workload is small, and the transformation period is short, so it has been widely used. Because urea has good stability, is non-toxic and harmless, has high safety and is easy to store, it is the best choice to use urea as the reducing agent in the SNCR method. Since urea is a solid particle, it needs to absorb heat when dissolving in water, and has a certain degree of corrosiveness, especially the diluted concentration, uniformity, particle size distribution of atomized particles, and sprayed temperature window have a great impact on the denitrification effect. At present, the actual denitrification efficiency of SNCR technology is only about 30%, and corrosion of the water wall at the injection site has already occurred, which restricts the application of SNCR technology.

Contents of the invention

In order to solve the problems existing in the background technology, the purpose of this utility model is to provide an SNCR flue gas denitrification device using urea as a reducing agent to solve the problems of solid urea particle dissolution, mixing and spraying, and realize the automatic, efficient and reliable operation of the SNCR device.

The technical scheme that the utility model solves its technical problem adopts is:

The utility model comprises a stirrer, a urea solution preparation tank, a heater, an industrial water main pipe, an industrial water regulating valve, a urea delivery pump, a urea solution storage tank, a urea injection pump, a mixer, a urea return regulating valve, and a pressurized industrial water regulating valve. Valve, industrial water pump, urea dilute solution regulating valve, atomizing steam regulating valve, atomizing steam main pipe and urea injection unit; the upper part of the urea solution preparation tank is connected with the industrial water main pipe through the industrial water regulating valve, and the urea solution preparation tank is equipped with The first heater and the agitator communicate with the urea solution preparation tank and the urea solution storage tank through the urea delivery pump; the second heater is arranged in the urea solution storage tank, and the urea injection pump inlet communicates with the lower part of the urea solution storage tank, The outlet of the urea injection pump is connected to the mixer and one end of the urea return regulating valve, and the other end of the urea return regulating valve is connected to the upper part of the urea solution storage tank; the middle of the mixer is connected to one end of the pressurized industrial water regulating valve, The other end of the pressurized industrial water regulating valve is connected with the outlet of the industrial water pump, and the inlet of the industrial water pump is connected with the industrial water main; the other end of the mixer is connected with one end of the urea dilute solution regulating valve, and the other end of the urea dilute solution regulating valve It communicates with the urea injection unit; the urea injection unit also communicates with one end of the atomizing steam regulating valve, and the other end of the atomizing steam regulating valve communicates with the atomizing steam main pipe.

The upper end of the urea solution preparation tank is also connected to the lower end of the solid urea storage tank through a solid urea feeder, and the upper end of the solid urea storage tank is connected to the solid urea tank truck through a solid urea regulating valve, a union, and a hose.

The mixer: includes a urea nozzle, a water pipe and a mixing nozzle; the large end of the urea nozzle is connected to the outlet of the urea injection pump, the small end of the urea nozzle is tapered, and there is a small hole inside the cone, and the urea nozzle is large The hole and the small hole are connected; the inlet end of the mixing nozzle matches the shoulder of the urea nozzle, and the inlet end of the mixing nozzle is followed by a large hole, a tapered hole, and a small hole in the direction of the outlet end, and there is a mixing hole inside the outlet end of the mixing nozzle. The small hole in the inlet end of the mixing nozzle is connected to the large hole, the large hole in the inlet end of the mixing nozzle is connected to one end of the water pipe, the other end of the water pipe is connected to one end of the pressurized industrial water regulating valve, and the outlet end of the mixing nozzle is connected to the urea dilute One end of the solution regulating valve is connected.

The urea injection unit: includes a urea spray gun, two comb-shaped plates, two side wall plates, a cover plate and a water wall tube bundle; the first comb-shaped plate, the first side wall plate, the second comb-shaped plate, the second The side wall panels form a rectangular frame, one side of the cubic frame is covered with a cover plate, the other side of the cubic frame is one side of the water-cooled wall tube bundle, and the other side of the water-cooled wall tube bundle is high-temperature flue gas, each water-cooled wall The tubes are installed in the slot of the comb-shaped plate and positioned; one of the water-cooled wall tubes in the water-cooled wall tube bundle is bent toward the cover plate in an arc shape, and a round hole is opened in the center of the cover plate, and the urea spray gun passes through the center hole of the cover plate and the circle of the water-cooled wall tube bundle. arc gap.

The two heaters are heated by electricity or by steam. The urea injection unit is installed at the flue gas of combustion equipment at 850-1150°C. The urea injection unit is one unit or multiple units connected in parallel.

The beneficial effect that the utility model has is:

Under the condition of canned urea, it can realize the automatic continuous feeding of canned urea, and ensure the concentration and uniformity of the urea solution, and automatically adjust the urea flow rate according to the NOx emission of the combustion equipment, so that the NOx emission of the combustion equipment is under control. Within the range, the denitrification effect is about 60%, and it can effectively prevent the corrosion of the water wall. Under the condition of bagged urea supply, the bagged urea is directly dismantled and put into the urea solution preparation tank manually, and the urea preparation adopts the intermittent operation mode, and the rest is the same as that with canned urea.

Description of drawings

Figure 1 is a schematic diagram of the layout of the SNCR urea system of the present invention.

Fig. 2 is a front view of the mixer of the present invention.

Fig. 3 is an A-A cross-sectional view of a schematic layout of the SNCR urea system of the present invention.

In the figure: 1. Solid urea tank truck, 2. Hose, 3. Union joint, 4. Solid urea regulating valve, 5. Solid urea storage tank, 6. Solid urea feeder, 7. Compressed air main pipe, 8. Compression Air regulating valve, 9. Agitator, 10. Urea solution preparation tank, 11. Heater, 12. Industrial water main, 13. Industrial water regulating valve, 14. Urea delivery pump, 15. Urea solution storage tank, 16. Urea Jet pump, 17, mixer, 18, urea reflux regulating valve, 19, pressurized industrial water regulating valve, 20, industrial water pump, 21, urea dilute solution regulating valve, 22, atomizing steam regulating valve, 23, atomizing steam Main pipe, 24, urea injection unit, 25, urea nozzle, 26, water pipe, 27, mixing nozzle, 28, urea spray gun, 29, comb plate, 30, side wall plate, 31, cover plate, 32, water wall tube bundle.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

As shown in Fig. 1, Fig. 2 and Fig. 3, the utility model comprises agitator 9, urea solution preparation tank 10, heater 11, industrial water main pipe 12, industrial water regulating valve 13, urea delivery pump 14, urea solution storage tank 15. Urea injection pump 16, mixer 17, urea return regulating valve 18, pressurized industrial water regulating valve 19, industrial water pump 20, urea dilute solution regulating valve 21, atomizing steam regulating valve 22, atomizing steam main pipe 23, urea Injection unit 24. The upper part of the urea solution preparation tank 10 communicates with the industrial water main pipe 12 through an industrial water regulating valve 13 and corresponding pipelines. A first heater 11 and an agitator 9 are installed in the urea solution preparation tank 10 . The communication between the urea solution preparation tank 10 and the urea solution storage tank 15 is realized through the urea delivery pump 14 and corresponding pipelines. A second heater 11 is arranged in the urea solution storage tank 15 . The inlet of the urea injection pump 16 is connected to the lower part of the urea solution storage tank 15 through a pipeline, and the outlet of the urea injection pump 16 is connected to the mixer 17 and one end of the urea return regulating valve 18 through a pipeline, and the other end of the urea return regulating valve 18 is connected to the urea solution storage tank 15. The upper part of the solution storage tank 15 is connected. The middle of the mixer 17 communicates with one end of the pressurized industrial water regulating valve 19 through a pipeline, the other end of the pressurized industrial water regulating valve 19 communicates with the outlet of the industrial water pump 20, and the inlet of the industrial water pump 20 communicates with the industrial water main pipe 12 . The other end of the mixer 17 communicates with one end of the urea dilute solution regulating valve 21 through a pipeline, and the other end of the urea dilute solution regulating valve 21 communicates with the urea injection unit 24 . The urea injection unit 24 also communicates with one end of the atomizing steam regulating valve 22 through a pipe, and the other end of the atomizing steam regulating valve 22 communicates with the atomizing steam main pipe 23 .

As shown in Figure 1, if the canned urea is available, it also includes solid urea tank truck 1, hose 2, union 3, solid urea regulating valve 4, solid urea storage tank 5, and solid urea feeder 6 , compressed air main pipe 7, compressed air regulating valve 8; the solid urea tank car 1 and the solid urea storage tank 5 are connected through the flexible pipe 2, the union 3, the solid urea regulating valve 4 and corresponding pipelines, and the solid urea can be transported by pneumatic transportation sent to the solid urea storage tank 5, the solid urea feeder 6 is connected in series to the lower part of the solid urea storage tank 5 and the upper part of the urea solution preparation tank 10 through the pipeline, and the lower part of the solid urea storage tank 5 passes through the compressed air regulating valve 8 and corresponding pipelines and Compressed air main pipe 7 communicates with each other.

As shown in Figure 2, the mixer 17: includes a urea nozzle 25, a water pipe 26 and a mixing nozzle 27; the large end of the urea nozzle 25 is connected to the outlet of the urea injection pump 16, and the outside of the large end of the urea nozzle 25 is a cylinder , there is a large hole inside, the small end of the urea solution nozzle 25 is tapered outside, and the inside of the cone has a small hole, the urea solution nozzle 25 large holes and small holes are connected; the inlet end of the mixing nozzle 27 is connected to the shoulder of the urea solution nozzle 25 Coordinated, the outside of the mixing nozzle 27 is a cylinder, and the inlet end of the mixing nozzle 27 is followed by a large hole, a tapered hole, and a small hole outward toward the outlet end, and the inside of the outlet end of the mixing nozzle 27 is provided with a small hole connected to the inlet end of the mixing nozzle 27. The large hole in the inlet end of the mixing nozzle 27 is connected with one end of the water pipe 26, the other end of the water pipe 26 is connected with one end of the pressurized industrial water regulating valve (19), and the outlet end of the mixing nozzle 27 is connected with the dilute urea One end of the solution regulating valve 21 is connected.

As shown in Figures 1 and 3, the urea injection unit 24: includes a urea spray gun 28, two comb-shaped plates 29, two side wall panels 30, a cover plate 31 and a water wall tube bundle 32; the first comb-shaped plate 29. The first side wall panel 30, the second comb-shaped panel 29, and the second side wall panel 30 enclose a square frame, one side of the cubic frame is covered with a cover plate 31, and the other side of the cubic frame is a water-cooled wall tube bundle 32, the other side of the water-cooled wall tube bundle 32 is high-temperature flue gas, and each water-cooled wall tube is installed in the comb-shaped plate groove; one of the water-cooled wall tube bundles 32 is curved in an arc shape to the cover plate 31, and the cover There is a circular hole in the center of the plate 31, and the urea spray gun 28 passes through the central circular hole of the cover plate and the arc-shaped gap of the water wall tube bundle 32.

The two heaters 11 are heated by electricity or by steam. The urea injection unit 24 is installed at the flue gas of the combustion equipment at 850-1150°C. The urea injection unit 24 is one unit or multiple units connected in parallel.

The working process of the present utility model is as follows:

1. Under the condition of having canned urea:

The canned urea can be conveyed to the solid urea storage tank 5 by pneumatic force, and the continuous and uniform metering and feeding of solid urea can be realized through the solid urea feeder 6, and the use of compressed air can ensure the reliability of solid urea particle feeding, avoiding the The feed blockage is caused by moisture absorption and accumulation. Since urea needs to absorb heat when dissolving in water, the urea solution preparation tank 10 is equipped with a heater 11, and its temperature is controlled at about 50° C., and the agitator 9 is configured to accelerate the dissolution of urea. The prepared urea solution is delivered to the urea solution storage tank 15 by the urea delivery pump 14 for standby, and the liquid level and the urea solution preparation tank 10 can be maintained by adjusting the opening degree of the industrial water regulating valve 13 and the feed rate of the solid urea feeder 6. The concentration of the solution does not change. The urea solution storage tank 15 is equipped with a heater 11 to keep the temperature constant. Urea injection pump 16, industrial water pump 20 and mixer 17 are used to dilute the urea solution. Generally, the pressure before the mixer 17 is kept constant through the pressurized industrial water regulating valve, and the urea is refluxed according to the NOx emission of the combustion equipment. The regulating valve 18 regulates the concentration of the dilute urea solution to ensure that the NOx emission is within the control range. The inlet of the mixing nozzle of the mixer 17 gradually shrinks from a large hole to a small hole. On the one hand, the pressure of the mixing point is reduced by throttling, which is beneficial to expand the pressure adjustment range of the urea solution, and on the other hand, it is beneficial to the uniform mixing of the urea solution and industrial water. . The urea injection unit includes a urea spray gun 28, a comb plate 29, a side wall plate 30, a cover plate 31, and a water wall tube bundle 32, and the urea spray gun is composed of a comb plate 29, a side wall plate 30, a cover plate 31, and a water wall tube bundle 32. The bracket ensures the geometric position of the spray gun and prevents the corrosion of the water-cooled wall tube caused by spraying urea. The atomized steam is used to atomize the dilute urea solution, so that the coarse and fine particles can be matched according to the requirements, and the mixing effect of the dilute urea solution and the flue gas can be improved. Using the above technologies, the automatic and continuous operation of the SNCR system can be realized, and the denitrification rate can be guaranteed to be around 60%, effectively avoiding the corrosion of the water wall.

2. Under the conditions of bagged urea supply:

Cancellation of solid urea tank car 1, hose 2, union 3, solid urea regulating valve 4, solid urea storage tank 5, solid urea feeder 6, compressed air main pipe 7, compressed air regulating valve 8; directly bagged The urea is demolished and put into the urea solution preparation tank 10. The urea preparation adopts the intermittent operation mode, that is, firstly adjust and maintain the temperature and liquid level of the urea solution preparation tank 10, calculate the industrial water weight according to the liquid level, and manually input the corresponding weight according to the concentration requirement. Urea, then start the agitator 8 and run for a certain period of time, finally the urea solution is passed to the urea solution storage tank 15 by the urea delivery pump 14, and the other conditions are the same as having canned urea.

The above-mentioned specific embodiments are used to explain the utility model, rather than to limit the utility model. Within the spirit of the utility model and the scope of protection of the claims, any modifications and changes made to the utility model fall into the scope of the utility model. scope of protection.

Claims (7)

1. one kind is the SNCR equipment for denitrifying flue gas of reducing agent with urea, it is characterized in that: comprise the preparation of agitator (9), urea liquid jar (10), a heater (11), industry water house steward (12), industry water control valve (13), urea delivery pump (14), urea liquid holding vessel (15), urea-spray pump (16), blender (17), urea return valve (18), pressurization industry water control valve (19), industrial water pump (20), urea weak solution control valve (21), atomizing steam control valve (22), atomizing steam house steward (23) and urea-spray unit (24); Urea liquid preparation jar (10) top is connected through industry water control valve (13) and industry water house steward (12); Be equiped with primary heater and agitator (9) in the urea liquid preparation jar (10), make the connection of urea liquid preparation jar (10) and urea liquid holding vessel (15) through urea delivery pump (14); The urea liquid holding vessel is provided with secondary heater in (15); Urea-spray pump (16) inlet is connected with the bottom of urea liquid holding vessel (15); Urea-spray pump (16) outlet links to each other with the end of blender (17) with urea return valve (18) respectively, and the other end of urea return valve (18) is connected with the top of urea liquid holding vessel (15); The centre of blender (17) is connected with an end of pressurization industry water control valve (19), and the other end of pressurization industry water control valve (19) is connected with industrial water pump (20) outlet, and the import of industrial water pump (20) is connected with industry water house steward (12); The other end of blender (17) is communicated with an end of urea weak solution control valve (21), and the other end of urea weak solution control valve (21) is connected with urea-spray unit (24); Urea-spray unit (24) also is communicated with an end of atomizing steam control valve (22), and the other end of atomizing steam control valve (22) is communicated with atomizing steam house steward (23).

2. according to claim 1 a kind of be the SNCR equipment for denitrifying flue gas of reducing agent with urea; It is characterized in that: also be communicated with solid urea storage tank (5) lower end through solid urea batcher (6) in described urea liquid preparation jar (a 10) upper end, solid urea storage tank (5) upper end is connected with solid urea tank car (1) through solid urea control valve (4), articulation (3), flexible pipe (2).

3. according to claim 1 a kind of be the SNCR equipment for denitrifying flue gas of reducing agent with urea, it is characterized in that: described blender (17) comprises urea mouth (25), water pipe (26) and combining nozzle (27); The big end macropore of urea mouth (25) links to each other with urea-spray pump (16) outlet, and the small end outside of urea mouth (25) is tapered, and cone-shaped internal part has aperture, and urea mouth (25) macropore and aperture are connected; The entrance point of combining nozzle (27) matches with the convex shoulder of urea mouth (25); Combining nozzle (27) entrance point is macropore, taper hole, aperture successively outside port of export direction; Combining nozzle (27) port of export inside has the macropore that is connected with the interior aperture of combining nozzle (27) entrance point; The inner macropore of combining nozzle (27) entrance point is connected with an end of water pipe (26); The other end of water pipe (26) is connected with an end of pressurization industry water control valve (19), and combining nozzle (27) port of export is communicated with an end of urea weak solution control valve (21).

4. according to claim 1 a kind of be the SNCR equipment for denitrifying flue gas of reducing agent with urea, it is characterized in that: described urea-spray unit (24) comprises urea spray gun, two comb plate, comb joints, two framed side wallboards, cover plate (31) and water-cooling walls tube banks (32); First comb plate, comb joint, first framed side wallboard, second comb plate, comb joint, second framed side wallboard surround the cube frame; One side cover of cube frame has cover plate (31); The opposite side of cube frame is a side of water-cooling wall tube bank (32); The opposite side of water-cooling wall tube bank (32) is a high-temperature flue gas, and every water screen tube is installed in the comb shape board slot locatees; Wherein water screen tube of water-cooling wall tube bank (32) is crooked to cover plate (31) circular arc, and cover plate (31) center has circular hole, and urea spray gun (28) passes cover plate center hole and water-cooling wall tube bank (32) circular arc space.

5. according to claim 1 a kind of be the SNCR equipment for denitrifying flue gas of reducing agent with urea, it is characterized in that: described two heaters adopt electrical heating or adopt Steam Heating.

6. according to claim 1 a kind of be the SNCR equipment for denitrifying flue gas of reducing agent with urea, it is characterized in that: described urea-spray unit (24) is installed on 850 ~ 1150 ℃ of flue gas places of combustion apparatus.

7. according to claim 1 a kind of be the SNCR equipment for denitrifying flue gas of reducing agent with urea, it is characterized in that: described urea-spray unit (24) is the parallel connection of a unit or a plurality of unit.

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