CN104524958A - Concentrated ammonia water online dilution device for SNCR denitration system - Google Patents

Abstract

The invention discloses a concentrated ammonia water online dilution device for an SNCR denitration system. The concentrated ammonia water online dilution device comprises a diluter consisting of a shell and a center pipe at the longitudinal center of the shell, wherein an inlet pipe communicated with an inner cavity of the shell is arranged on the upper part of the outer wall of the shell, the lower end of the center pipe is an open end, and the upper end of the center pipe is connected with an outlet pipe communicated with a spray gun in a boiler furnace. The upper end of the shell is closed, and the lower end of the shell is connected with a slag storage pipe; a dilution water inlet is formed in the front end of the inlet pipe, a nozzle for spraying concentrated ammonia water into the inlet pipe is arranged on the side wall of the inlet pipe, dilution water and concentrated ammonia water are mixed and then enter a cavity between the shell and the center pipe to flow downwards in vortex, and after being further mixed, the mixture enters the center pipe, then is transferred into the outlet pipe, and finally enters the spray gun of the furnace for spray atomization. Paths for circulation of diluted ammonia water are all cavities, so that only very low pipeline loss can be caused, and the flowing speed of the mixture entering the gun spray is high, so that the atomization effect during the spraying of the gun spray is improved, and the denitration rate of the system for flue gas is improved. The cavity between the shell and the center pipe can also be used for removing impurities in the diluted ammonia water, thus avoiding clogging of the nozzle of the spray gun.

Description

Concentrated ammonia water online dilution device for SNCR denitrification system

technical field

The invention relates to an SNCR denitration system, in particular to an online dilution device for concentrated ammonia water in the SNCR denitration system.

Background technique

SNCR denitrification uses the boiler furnace as the denitrification reaction device, and sprays dilute ammonia solution in the temperature range of 850°C to 1100°C. The concentration of purchased ammonia water is about 20%, and it needs to be diluted to a concentration of 10% before spraying.

At present, the SNCR denitrification ammonia water dilution device basically adopts a double-layer pipe type or a structure with mixing blades in the pipe. They have two problems: first, the system resistance is too large, and the resistance between the double-layer pipes and the blades in the pipe cause the liquid flow. The resistance of the diluted ammonia water will affect the injection effect of the diluted ammonia water; the second is that the impurities in the diluted water and ammonia water cannot be filtered before entering the nozzle of the furnace spray gun. Long-term use will make the nozzle easy to accumulate impurities in the solution and block the nozzle. Further reduce the atomization effect of the nozzle spraying dilute ammonia water.

Contents of the invention

The purpose of the present invention is to provide an on-line diluting device for concentrated ammonia water with stable performance, low resistance, and improved effect of spraying dilute ammonia water from a furnace spray gun, so as to improve the denitrification rate of flue gas by the SNCR denitrification system.

The invention discloses an on-line diluting device for concentrated ammonia water used in an SNCR denitrification system. The lower end is an open end, and the upper end is connected with an outlet pipe that communicates with the spray gun in the boiler furnace. The upper end of the shell is closed, and the lower end is connected with a slag storage pipe. ammonia nozzle.

The shell is formed by connecting a cylinder and a conical bucket up and down, the lower end of the central tube extends into the conical bucket, and the upper end passes through the upper surface of the cylinder.

The inlet pipe is a square pipe connected along the tangential direction of the outer wall of the cylinder.

There are two rows of ammonia water nozzles, symmetrically arranged on the left and right sides of the front end of the inlet pipe.

The inner wall at the lower end of the slag storage pipe is threadedly connected with a plug.

In the present invention, a row of nozzles is arranged on both sides of the inlet pipe perpendicular to the dilution water flow to spray concentrated ammonia water into the dilution water flow, so as to ensure mutual compensation of the spray coverage between the nozzles on both sides, so that the dilution water flow can be sprayed without blind spots, realizing The homogeneity of ammonia dilution mixing. After the concentrated ammonia water and dilution water are mixed in the inlet pipe, they enter the cavity between the shell and the central tube along the tangential direction of the shell and vortex downward to further strengthen the mixing effect, then enter it from the lower end of the central tube and continue mixing upwards. From the top of the central tube to the outlet tube, and finally into the spray gun installed in the boiler furnace to spray and atomize to realize the SNCR denitrification reaction.

The above-mentioned structure enables the concentrated ammonia water to spray and atomize from the spray gun that enters the boiler furnace from the dilution process, and the mixed solution circulation path is all cavities, without any obstacles, without adding additional resistance, only pipeline loss, which is different from the traditional inner and outer tubes. Compared with the built-in vane type ammonia mixer, the energy loss in the entire flow path is very small, and the flow rate into the spray gun in the furnace is fast, which improves the atomization effect of the spray gun nozzle, thereby improving the system's flue gas denitrification rate.

While the mixed solution is vortexing downward in the cavity between the shell and the central tube, the impurities in the solution are thrown to the inner wall of the shell due to centrifugal force, and then gradually spiral down under the action of its own gravity through the conical tube. After the bucket enters the slag storage pipe, the dilute ammonia solution after removal of impurities prevents the nozzle of the spray gun from being blocked, and further improves the atomization effect when the nozzle sprays dilute ammonia water, thereby further improving the denitrification rate of the flue gas and prolonging the service life of the spray gun.

Description of drawings

Fig. 1 is a schematic diagram of the front view structure of an example of the present invention.

FIG. 2 is a schematic top view of FIG. 1 .

Fig. 3 is a schematic diagram of the arrangement of nozzles in the inlet pipe in Fig. 1 .

Detailed ways

As shown in Figures 1 to 3, the present invention discloses an on-line dilution device for concentrated ammonia water used in SNCR denitrification systems, including a housing 1, an inlet pipe 2, a center pipe 3, an outlet pipe 4, a slag storage pipe 5 and wire Block 6. The casing 1 is formed by connecting a cylinder 11 and a conical bucket 12 up and down, and the upper end of the cylinder 11 is a closed end. The inlet pipe 2 is a square pipe, which is connected tangentially to the outer wall of the cylinder 11 and communicates with the inner cavity of the cylinder 11 . The central pipe 3 is located at the axial center of the casing 1 , its lower end extends into the conical bucket 12 , and its upper end passes through the upper end surface of the cylinder 11 . The outlet pipe 4 is connected to the upper end of the central pipe 3, and its outlet end communicates with the spray gun in the boiler furnace. The slag storage pipe 5 is connected to the outlet end of the conical bucket 12, and the inner wall of its lower end is connected to the plug 6 by threads. The front end of the inlet pipe 2 is the dilution water inlet, and the left and right side walls are symmetrically arranged with thick ammonia water pipes 7, and the corresponding inlet pipe sections on the ammonia water pipe 7 are connected with several taps 8 extending into the inlet pipe 2. The end is connected to the nozzle 9, and the arrangement of the nozzle 9 is based on the fact that the effective spraying range of the nozzles on both sides covers 100% of the cross section of the inlet pipe 2, so as to ensure 100% full mixing of the dilution water and the concentrated ammonia water.

The mixed solution enters the cavity between the outer wall of the central tube and the inner wall of the shell in a tangential direction, and the stroke of the mixed solution in the cavity is a vortex shape. While strengthening the mixing effect, impurities with a specific gravity different from the liquid are Due to the action of centrifugal force, it is thrown to the inner wall of the shell, and gradually spirally descends into the slag storage pipe at the lower end of the conical bucket under the action of gravity to realize the function of removing impurities and prevent the spray gun nozzle in the boiler furnace from being blocked by impurities. After removing impurities, the diluted ammonia solution enters the center tube and continues to mix to reach the design concentration, then turns to enter the outlet tube, and finally enters the spray gun installed in the boiler furnace to spray and atomize to realize the SNCR denitrification reaction.

The above-mentioned structure of the present invention makes the concentrated ammonia water spray and atomize from entering the dilution process to the spray gun entering the boiler furnace, and the mixed liquid circulates along a reasonable path without any obstructions, and is mixed with the traditional inner and outer tube type ammonia water mixer and built-in blade type ammonia water Compared with the device, the system resistance of the mixed liquid is greatly reduced, thereby improving the subsequent denitrification effect. At the same time, the function of removing impurities in the mixed liquid is realized under the action of centrifugal force and gravity, and the hidden danger of impurities in the mixed liquid blocking the spray gun in the furnace of the boiler is avoided. Impurities in the slag storage pipe can be removed by removing the plug.

Claims (5)

1. A strong ammonia water online dilution device for SNCR denitrification system, characterized in that: the device includes a diluter made up of a shell and a central tube in its longitudinal center, and the upper part of the outer wall of the shell has an inlet pipe connected to its inner cavity , the lower end of the central pipe is an open end, and the upper end is connected with an outlet pipe connected to the spray gun in the boiler furnace. The upper end of the shell is closed, and the lower end is connected with a slag storage pipe. Ammonia nozzles for spraying concentrated ammonia water. 2. The concentrated ammonia water on-line dilution device for SNCR denitrification system as claimed in claim 1, characterized in that: the housing is formed by connecting a cylinder and a conical bucket up and down, and the lower end of the central tube extends into the conical bucket The inner and upper ends pass through the upper end surface of the cylinder. 3. The concentrated ammonia water on-line dilution device for SNCR denitrification system according to claim 2, characterized in that: the inlet pipe is a square pipe connected along the tangential direction of the outer wall of the cylinder. 4. The concentrated ammonia water on-line dilution device for SNCR denitrification system according to claim 1, characterized in that: said ammonia water nozzles have two rows, symmetrically arranged on the left and right sides of the front end of the inlet pipe. 5. The concentrated ammonia water on-line dilution device for SNCR denitrification system according to claim 1, characterized in that: the inner wall of the lower end of the slag storage pipe is connected with a plug through a screw thread.