CN209917610U

CN209917610U - SNCR deNOx systems

Info

Publication number: CN209917610U
Application number: CN201920655501.1U
Authority: CN
Inventors: 梅晟东; 陈新建; 曹民侠; 陈在伟
Original assignee: Wuhan Liwei Engineering Technology Co Ltd
Current assignee: Wuhan Liwei Engineering Technology Co Ltd
Priority date: 2019-05-08
Filing date: 2019-05-08
Publication date: 2020-01-10
Anticipated expiration: 2029-05-08

Abstract

The utility model relates to a SNCR deNOx systems, in particular to SNCR deNOx systems of circulating fluidized bed boiler. An SNCR (selective non-catalytic reduction) denitration system comprises a boiler body and a separator, wherein the boiler body is connected with the separator through an inlet flue, the separator is also provided with an outlet flue, the boiler body is also provided with a plurality of secondary air channels, and the secondary air channels are connected with the boiler body through elbow air pipes; and spray guns are arranged in the inlet flue, the outlet flue and the elbow air pipe. The utility model discloses a denitration efficiency problem for solving among the prior art under the unable assurance circulating fluidized bed boiler full load operating mode, the problem of denitration inefficiency under the full load operating mode promptly. The utility model discloses a requirement that the realization circulating fluidized bed boiler minimum that can be better discharges through the setting of different positions, different forms's spray gun.

Description

SNCR deNOx systems

Technical Field

The utility model relates to a SNCR deNOx systems, in particular to SNCR deNOx systems of circulating fluidized bed boiler.

Background

Selective non-catalytic reduction (SNCR) refers to the reduction of nitrogen oxides in flue gas to harmless nitrogen and water by spraying a reducing agent within a "temperature window" suitable for denitration reaction without the action of a catalyst. The technology generally adopts ammonia, urea or hydrogen ammonia acid sprayed in a furnace as a reducing agent to reduce NOx. The reductant reacts only with NOx in the flue gas and generally does not react with oxygen, and this technique does not employ a catalyst, so this method is referred to as selective non-catalytic reduction (SNCR). Since the process does not use a catalyst, the reducing agent must be added in the high temperature zone. And spraying the reducing agent into a region with the temperature of 850-1100 ℃ in the hearth, quickly thermally decomposing into NH3, and reacting with NOx in the flue gas to generate N2 and water.

The circulating fluidized bed boiler adopts the clean coal combustion technology with the highest industrialization degree. The circulating fluidized bed boiler adopts fluidized combustion, and the main structure comprises a combustion chamber (comprising a dense phase region and a dilute phase region) and a circulating return furnace (comprising a high-temperature gas-solid separator and a return system). At present, under the new trend of 'insisting on the global co-treatment and source prevention, continuously implementing the action of preventing and treating the atmospheric pollution and winning the blue-day guard war', the concentration of PM2.5 is required to be further obviously reduced, the heavy pollution days are obviously reduced, the quality of the atmospheric environment is obviously improved, and the blue-day happiness of people is obviously enhanced. Circulating fluidized bed boilers also face stricter requirements on ultralow emission, and most of the existing circulating fluidized bed boilers adopt a mode of low-nitrogen combustion plus SNCR denitration to reduce the emission of NOx.

Chinese patent a spray gun arrangement structure for SNCR denitration system (application No. CN201520385787), comprising: the boiler furnace and the cyclone separator are communicated through at least two separator inlet sections, and the reducing agent spray gun is respectively arranged on the outer side plate and the upper top plate of each separator inlet section. Because the separator induction zone circulation cross-section is narrower, the reductant can be here with the flue gas intensive mixing after spouting, arranges the spray gun of roof on the induction zone simultaneously and has effectively increased the jet depth of reductant, has increased the area covered, promotes the promotion of system denitration efficiency. However, the SNCR spray gun arrangement in the mode has defects, denitration under the full-load working condition of the circulating fluidized bed boiler can not be ensured frequently, namely, denitration efficiency is low under the full-load working condition, and the SCR denitration technology brings huge cost and secondary pollution of catalyst hazardous waste products to enterprises, so that the installation position of the existing spray gun needs to be optimized under the existing low-nitrogen and SNCR denitration mode, and ultralow emission of the circulating fluidized bed boiler is ensured.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a SNCR deNOx systems for solve among the prior art problem of denitration inefficiency under the circulating fluidized bed boiler full load operating mode.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

an SNCR (selective non-catalytic reduction) denitration system comprises a boiler body and a separator, wherein the boiler body is connected with the separator through an inlet flue, the separator is also provided with an outlet flue, the boiler body is also provided with a plurality of secondary air channels, and the secondary air channels are connected with the boiler body through elbow air pipes; the method is characterized in that: and spray guns are arranged in the inlet flue, the outlet flue and the elbow air pipe.

Furthermore, an expansion joint is arranged in the inlet flue, and the spray gun is positioned in front of the expansion joint.

Furthermore, a plurality of spray guns which are vertically and evenly arranged into a line are arranged in the inlet flue, and the spray guns are positioned on the side surface of the inlet flue.

Furthermore, the jet angle of the spray gun at the inlet flue is not more than 60 degrees, the spraying end of the spray gun extends into the inlet flue by 10mm, and the spray gun 6 inclines downwards by 3-10 degrees.

Furthermore, the spray gun in the elbow air pipe and the elbow air pipe are coaxially arranged.

Furthermore, a plurality of secondary air channels are uniformly arranged on the boiler body in the circumferential direction, and are arranged in two layers from top to bottom, and spray guns are arranged in the elbow air pipes positioned on the upper layer.

Furthermore, the jet angle of the spray gun at the elbow air pipe is less than or equal to 90 degrees.

Furthermore, a plurality of spray guns are uniformly and symmetrically arranged in the outlet flue, the included angle between each spray gun and the central line of the outlet flue is less than or equal to 90 degrees, and the jet angle of each spray gun is more than or equal to 60 degrees and less than or equal to 120 degrees.

Furthermore, the spray gun input is connected with the injection control module, the injection control module is including the atomizing air pipe way that is used for letting in atomizing air to the spray gun, the reductant pipeline that is used for letting in the reductant to the spray gun and the cooling air pipeline that is used for letting in cooling air to the spray gun.

Furthermore, a filter, a delivery pump, a check valve, a regulating valve, a mixer, a flowmeter and a pressure measuring device are sequentially arranged on the reducing agent pipeline along the flow direction; the device is characterized in that a dilution water pipeline for introducing dilution water is connected to the raw agent pipeline, the output end of the dilution water pipeline is connected with the input end of the mixer, and a filter, a delivery pump, a check valve, a regulating valve, a flowmeter and a pressure measuring device are sequentially arranged on the dilution water pipeline in the flow direction.

The utility model has the advantages that: the utility model discloses a denitration efficiency problem for solving among the prior art under the unable assurance circulating fluidized bed boiler full load operating mode, the problem of denitration inefficiency under the full load operating mode promptly. The utility model discloses a requirement that the realization circulating fluidized bed boiler minimum that can be better discharges through the setting of different positions, different forms's spray gun. And the problem that the NOx emission index in the prior art can not meet the requirement of ultra-clean emission can be solved. The utility model discloses a SNCR spray gun can guarantee SNCR deNOx systems's efficiency in the setting of boiler and separator relevant position, can realize the purpose of the ultralow emission of boiler nitrogen oxide.

Drawings

Fig. 1 is an overall schematic view of the present invention.

Fig. 2 is a schematic structural diagram of the middle injection control module according to the present invention.

In the figure: 1. the device comprises a boiler body, a separator, a secondary air channel; 10. atomizing air pipeline, 11, cooling air pipeline, 12, reducing agent pipeline, 13, dilution water pipeline, 14, ball valve, 15, pressure regulating valve, 16, pressure measuring device, 17, flowmeter, 18, filter, 19, delivery pump, 20, check valve, 21, regulating valve, 22 and mixer.

Detailed Description

For better understanding of the present invention, the technical solution of the present invention will be further described below with reference to the following embodiments and accompanying drawings.

An SNCR (selective non-catalytic reduction) denitration system comprises a boiler body 1 and a separator 2, wherein the boiler body 1 is connected with the separator 2 through an inlet flue 3, the separator 2 is also provided with an outlet flue 8, and the inlet flue 3 is provided with an expansion joint 4; still be equipped with a plurality of secondary wind channels 5 on the boiler body 1, a plurality of secondary wind channels 5 circumference evenly arranges on boiler body 1 to arrange two-layerly from top to bottom, secondary wind channel 5 passes through elbow tuber pipe 9 and boiler body 1.

Five spray guns 6 which are vertically and uniformly arranged in a row are arranged in front of the expansion joint 4 in the inlet flue 3, the five spray guns 6 are positioned on the side surface of the inlet flue 3, the spray guns 6 are arranged according to the height of the flue and the section of the flue, and the distance between two adjacent spray guns 6 is kept at 500-1200 mm generally. The jet angle of the spray gun 6 is less than or equal to 60 degrees, the spraying end of the spray gun 6 extends into the inlet flue 3 by 10mm (preferably, the spray gun 6 with small flow and large rigid jet flow is adopted), and the spray gun 6 inclines downwards by 3-10 degrees. Because the front part of the expansion joint 4 belongs to the flaring section of the flue, and the rear part of the expansion joint 4 belongs to the necking section of the flue connected with the separator 2, the spray gun 6 is arranged in front of the expansion joint 4, so that the flue gas and the reducing agent can be well mixed. Because the flow of flue gas in the flue belongs to a strong turbulence flow, the velocity of flow is high, adopt vertical evenly arranged can realize the flue gas in the 4 flue sections of expansion joint and the intensive mixing of reductant, guarantee denitration efficiency, and in the different flue gas volume of different loads, can spout the adjustment of ammonia volume through every spray gun 6, realize the intensive mixing of reductant and flue gas in the flue section, guarantee denitration efficiency. In order to avoid the injection influence of the wall surface on the jet flow of the spray gun 6 and ensure that the current situation that the furnace wall is corroded by the reducing agent dropping liquid is not generated due to the existence of faults, the injection end of the spray gun 6 is extended into the inlet flue 3 by 10mm, and the spray gun 6 is installed in a mode of inclining downwards by 3-10 degrees; because the flow velocity at the inlet flue 3 is high, if the jet angle of the spray gun 6 is too large, the reducing agent cannot penetrate through the central position of the flue gas, the jet angle of the spray gun 6 at the inlet flue 3 is not more than 60 degrees, and the reducing agent can well penetrate through the central position of the flue gas and can be fully reflected with the flue gas.

The spray gun 6 is arranged in the elbow air pipe 9 on the upper layer, the spray gun 6 and the elbow air pipe 9 are coaxially arranged (namely the spraying direction of the spray gun 6 is consistent with the air outlet direction of the elbow air pipe 9), the jet angle of the spray gun 6 is less than or equal to 90 degrees, and the spray gun 6 with small flow and small particle size is preferably adopted. Because the lower secondary air duct 5 is generally arranged in the dense-phase area of the boiler, and the upper secondary air duct 5 is arranged in the dilute-phase area of the boiler, the dense-phase area has large fuel turbulence intensity, and the spray gun 6 is arranged in the upper secondary air duct 5, so that the penetrability of the reducing agent can be better realized. Because boiler brickwork width is wide, and the arrangement of elbow tuber pipe 9 satisfies width direction's coverage, so adopt spray gun 6 to arrange the mode at elbow tuber pipe 9 to spray gun 6 is coaxial with elbow tuber pipe 9, satisfies fluidic homophase nature needs, has also guaranteed the efflux rigidity and the penetrability needs of reductant simultaneously. Because the spray gun 6 at the elbow air pipe 9 is used at low load of the boiler, the smoke gas amount is small at low load, and the spray gun with the jet angle not more than 90 degrees can realize the atomization effect of the reducing agent and ensure the penetration of the reducing agent.

A plurality of spray guns 6 are uniformly and symmetrically arranged in the outlet flue 8, the included angle between each spray gun 6 and the central line of the outlet flue 8 is less than or equal to 90 degrees, and the jet angle of each spray gun 6 is more than or equal to 60 degrees and less than or equal to 120 degrees. The spray gun 6 with small flow and large coverage is preferably adopted, and because the spray gun 6 at the outlet flue 8 is used as the supplementary spray gun 6, the spray gun 6 only needs to adopt the spray gun 6 with good atomization effect and wide coverage, and therefore the spray gun 6 with the jet flow angle of more than or equal to 60 degrees and less than or equal to 120 degrees is adopted as the supplementary spray gun 6.

The utility model discloses a principle and application method: when the boiler is under low load, because the temperature at the separator 2 is difficult to reach 850-1100 ℃, and the temperature of the hearth can meet the requirements of SNCR denitration, in order to reduce NOx emission and enable the boiler emission to reach the ultra-low emission requirement, a spray gun 6 is required to be arranged in an elbow air pipe 9 at the hearth; and when the boiler is in high load, because the temperature of the hearth and the temperatures of the inlet and the outlet of the separator 2 can simultaneously meet the requirement of spraying the reducing agent, in order to ensure that the reducing agent with the lowest consumption is used, the spray gun 6 at the expansion joint 4 at the inlet of the separator 2 is mainly adopted to spray the reducing agent, and the spray gun 6 at the outlet of the separator 2 is used as a supplementary spraying mode to realize the full mixing of the flue gas and the reducing agent, and finally, the requirements of low reducing agent consumption and ultralow emission are realized.

The input ends of all the spray guns 6 are connected with a spray control module 7, and the spray control module 7 comprises an atomization air pipeline 10 for introducing atomization air into the spray guns 6, a reducing agent pipeline 12 for introducing a reducing agent into the spray guns 6 and a cooling air pipeline 11 for introducing cooling air into the spray guns 6. In order to ensure atomization of the reducing agent and cooling of the lance 6, an atomization air duct 10 and a cooling air duct 11 are added to the lance 6.

One end of the atomization air pipeline 10 is connected with a compressed air inlet of the spray gun 6, and atomization air is introduced into the other end of the atomization air pipeline; the atomizing air pipeline 10 is sequentially provided with a ball valve 14, a pressure regulating valve 15, a pressure measuring device 16 and the ball valve 14 along the flow direction.

One end of the reducing agent pipeline 12 is connected with a reducing agent solution inlet of the spray gun 6, and the reducing agent is introduced into the other end of the reducing agent pipeline; a ball valve 14, a filter 18, a delivery pump 19, a check valve 20, a ball valve 14, a regulating valve 21, a ball valve 14, a mixer 22, a flowmeter 17, a ball valve 14 and a pressure measuring device 16 are sequentially arranged on the reducing agent pipeline 12 along the flow direction (the ball valve 14 is arranged between the pressure measuring device 16 and the dilution water pipeline 13); the raw agent pipeline 12 is connected with a dilution water pipeline 13 for introducing dilution water, the output end of the dilution water pipeline 13 is connected with the input end of a mixer 22, and a ball valve 14, a filter 18, a delivery pump 19, a check valve 20, a ball valve 14, a regulating valve 21, a flowmeter 17, a ball valve 14 and a pressure measuring device 16 (the ball valve 14 is arranged between the pressure measuring device 16 and the dilution water pipeline 13) are sequentially arranged on the dilution water pipeline 13 along the flow direction. Because the consumption of the reducing agent is small, in order to ensure the design requirement of a reducing agent process system, the reducing agent needs to be diluted to a certain range to meet the requirements of a pump valve and the like, and in order to ensure the sufficient mixing of the dilution water and the reducing agent, the dilution water and the reducing agent need to be uniformly mixed through the mixer 22.

One end of the cooling air pipeline 11 is connected with a cooling air inlet of the spray gun 6, the other end of the cooling air pipeline is communicated with cooling air, and a ball valve 14 is arranged on the cooling air pipeline 11.

The reducing agent pipe 12 and the dilution water pipe 13 are provided with flow meters 17 to ensure the metering accuracy of the reducing agent.

The reducing agent pipeline 12 and the dilution water pipeline 13 are provided with a regulating valve 21 and a pressure measuring device 16, so as to meet the requirements of reducing agents in different boilers. And is used to adjust the flow balance and pressure balance of each branch line.

According to the SNCR denitration system, mixed reducing agents are conveyed to spray guns 6 through injection control modules 7, injection parameters of the injection control modules 7 are adjusted according to the position conditions of the injection control modules 7, and the reducing agents are sprayed to corresponding positions in a boiler body 1 and a separator 2 through the spray guns 6.

The above description is only an example of the present invention, and certainly, the scope of the present invention should not be limited thereto, and therefore, the present invention is not limited to the above description.

Claims

1. An SNCR (selective non-catalytic reduction) denitration system comprises a boiler body (1) and a separator (2), wherein the boiler body (1) is connected with the separator (2) through an inlet flue (3), an outlet flue (8) is further arranged on the separator (2), a plurality of secondary air channels (5) are further arranged on the boiler body (1), and the secondary air channels (5) are connected with the boiler body (1) through elbow air pipes (9); the method is characterized in that: and spray guns (6) are arranged in the inlet flue (3), the outlet flue (8) and the elbow air pipe (9).

2. The SNCR denitration system of claim 1, wherein: an expansion joint (4) is arranged in the inlet flue (3), and the spray gun (6) is positioned in front of the expansion joint (4).

3. The SNCR denitration system of claim 1, wherein: a plurality of spray guns (6) which are vertically and evenly arranged into a line are arranged in the inlet flue (3), and the spray guns (6) are positioned on the side surface of the inlet flue (3).

4. The SNCR denitration system of claim 1, wherein: the jet flow angle of the spray gun (6) at the inlet flue (3) is not more than 60 degrees, the spray end of the spray gun (6) extends into the inlet flue (3) by 10mm, and the spray gun (6) inclines downwards by 3-10 degrees.

5. The SNCR denitration system of claim 1, wherein: and the spray gun (6) in the elbow air pipe (9) and the elbow air pipe (9) are coaxially arranged.

6. The SNCR denitration system of claim 1, wherein: a plurality of secondary air ducts (5) are uniformly arranged on the boiler body (1) in the circumferential direction, are arranged in two layers from top to bottom, and are internally provided with spray guns (6) in elbow air pipes (9) positioned on the upper layer.

7. The SNCR denitration system of claim 1, wherein: the jet angle of the spray gun (6) at the elbow air pipe (9) is less than or equal to 90 degrees.

8. The SNCR denitration system of claim 1, wherein: a plurality of spray guns (6) are uniformly and symmetrically arranged in the outlet flue (8), the included angle between each spray gun (6) and the central line of the outlet flue (8) is less than or equal to 90 degrees, and the jet angle of each spray gun (6) is more than or equal to 60 degrees and less than or equal to 120 degrees.

9. The SNCR denitration system of claim 1, wherein: the spray gun is characterized in that the input end of the spray gun (6) is connected with a spray control module (7), and the spray control module (7) comprises an atomization air pipeline (10) for introducing atomization air into the spray gun (6), a reducing agent pipeline (12) for introducing a reducing agent into the spray gun (6) and a cooling air pipeline (11) for introducing cooling air into the spray gun (6).

10. The SNCR denitration system according to claim 9, wherein: a filter (18), a delivery pump (19), a check valve (20), a regulating valve (21), a mixer (22), a flowmeter (17) and a pressure measuring device (16) are sequentially arranged on the reducing agent pipeline (12) along the flow direction; the device is characterized in that a dilution water pipeline (13) for introducing dilution water is connected to the raw agent pipeline (12), the output end of the dilution water pipeline (13) is connected with the input end of a mixer (22), and a filter (18), a delivery pump (19), a check valve (20), a regulating valve (21), a flow meter (17) and a pressure measuring device (16) are sequentially arranged on the dilution water pipeline (13) in the flow direction.