CN217829526U

CN217829526U - High-efficient regulation and control of flue gas denitration spouts ammonia grid

Info

Publication number: CN217829526U
Application number: CN202221847696.8U
Authority: CN
Inventors: 郭俊冬; 崔浩东
Original assignee: Beijing Bohuitong S & T Development Co ltd
Current assignee: Beijing Bohuitong S & T Development Co ltd
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2022-11-18
Anticipated expiration: 2032-07-19

Abstract

The utility model relates to a high-efficient regulation and control of flue gas denitration ammonia injection grid, including detection facility and a plurality of ammonia injection grid unit, ammonia injection grid unit includes many branch pipes that center on and connect the person in charge, and each ammonia injection grid unit is equipped with governing valve and pressure difference sampling point, and each pressure difference sampling point is connected through the outer pressure difference transmission facility of respective instrument pipe and flue respectively, and pressure difference transmission facility and each ammonia injection grid unit's regulating valve information connection. The utility model discloses put the central point with each traditional ammonia injection grid and set up the pressure differential sampling point, calculate each ammonia injection grid unit flue gas flow through the differential pressure value, according to the flue gas flow of each ammonia injection grid department in the flue cross-section distribution condition, the ammonia spraying amount of each ammonia injection grid of accurate regulation and control realizes the purpose of accurate, evenly spraying ammonia. Compared with the traditional ammonia injection grid, the denitration efficiency is improved by more than 1.4 times, the ammonia escape amount is greatly reduced, and the ammonia gas consumption is saved, so that the operation cost is greatly reduced.

Description

High-efficient regulation and control of flue gas denitration spouts ammonia grid

Technical Field

The utility model relates to a high-efficient regulation and control ammonia injection grid of flue gas denitration is a firing the environmental protection auxiliary facilities of burning furnace, is a facility that is used for the flue gas pollutant of burning furnace to purify, especially the environmental protection auxiliary facilities in the aspect of the flue gas denitration.

Background

Nitrogen oxides (NOx), one of the most important atmospheric pollutants today, are usually released from stationary pollution sources, such as industrial boilers, gas turbines, coal-fired power plants, etc., which severely pollute the atmospheric environment and human health. The flue gas denitration engineering reduces the emission of nitrogen oxides and reduces the threat of the nitrogen oxides to the atmospheric environment and the human health, and a Selective Catalytic Reduction (SCR) flue gas denitration technology is widely applied to the flue gas denitration engineering due to simple operation and high denitration efficiency. The SCR flue gas denitration technology is characterized in that ammonia gas with a certain concentration is sprayed into flue gas through an ammonia spraying grid to be mixed with the flue gas, and chemical reduction reaction is generated under the action of a downstream catalyst, so that the concentration of nitrogen oxides in the flue gas is reduced. At present, although the ammonia injection grid is transformed and upgraded for many times, the problems that nitrogen oxides in smoke gas escape in large quantity to cause the nitrogen oxides to exceed standards, ammonia escape to exceed standards, and the ammonia injection grid is difficult to level and adjust in the ammonia injection amount cannot be solved due to uneven ammonia injection caused by uneven flow field and flow rate of smoke gas in a flue and inaccurate regulation and control of the ammonia injection amount of each ammonia injection unit. Therefore, to current flue gas denitration ammonia injection grid, how to improve the ammonia injection degree of consistency, nitrogen oxide in the further reduction flue gas improves the efficiency of environmental protection ammonia injection grid, is a problem that needs to be solved.

Disclosure of Invention

In order to overcome the problem of prior art, the utility model provides a high-efficient regulation and control of flue gas denitration spouts ammonia grid. The ammonia injection grating monitors the flue gas flow at the central position of each ammonia injection grating unit, and the ammonia injection amount of each ammonia injection grating unit is in direct proportion to the flue gas flow, so that accurate ammonia injection is realized.

The purpose of the utility model is realized like this: an ammonia injection grid for efficiently regulating and controlling flue gas denitration comprises a detection facility arranged in a flue of a combustion furnace for detecting nitrogen oxides and a plurality of ammonia injection grid units uniformly distributed in the flue, wherein each ammonia injection grid unit comprises a plurality of branch pipes surrounding and connected with a main pipe, a plurality of ammonia injection ports are arranged on each branch pipe, a regulating valve and a pressure difference sampling point are respectively arranged on the main pipe of each ammonia injection grid unit, each pressure difference sampling point is respectively connected with a pressure difference transmitting facility which is arranged outside the flue and can calculate the flow of the flue gas passing through each ammonia injection grid unit through a pressure difference value through a respective instrument guide pipe, and the pressure difference transmitting facility is in information connection with the regulating valve of each ammonia injection grid unit.

Furthermore, the ammonia injection grid units are uniformly distributed in the flue with the rectangular cross section in a grid shape, branch pipes of the ammonia injection grid units are respectively in an H shape, and the pressure difference sampling point is arranged at the midpoint of a middle connecting line of the H shape.

Furthermore, the two sampling ports of the pressure difference sampling point are arranged along the flowing direction of the flue gas.

Furthermore, each instrument conduit is provided with a back-blowing facility.

Furthermore, the regulating valve is an electric control regulating valve.

Furthermore, the electric control regulating valve is connected with an operation controller, and the operation controller is connected with a detection facility for detecting nitrogen oxides and a pressure transmitter.

The utility model has the advantages and beneficial effects that: the utility model discloses put the central point with each traditional ammonia injection grid and set up the pressure differential sampling point, calculate each ammonia injection grid unit flue gas flow through the differential pressure value, according to the flue gas flow of each ammonia injection grid department in the flue cross-section distribution condition, the ammonia spraying amount of each ammonia injection grid of accurate regulation and control realizes the purpose of accurate, evenly spraying ammonia. Compared with the traditional ammonia injection grid, the denitration efficiency is improved by more than 1.4 times, the ammonia escape amount is greatly reduced, and the ammonia gas consumption is saved, so that the operation cost is greatly reduced.

Drawings

The present invention will be further explained with reference to the drawings and examples.

FIG. 1 is a schematic block diagram of an ammonia injection grid according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an ammonia injection grid according to a first embodiment and a second embodiment of the present invention;

FIG. 3 is a schematic view of the arrangement of the sampling ports and the back-blowing device according to the third and fourth embodiments of the present invention;

fig. 4 is an electric control schematic block diagram of an ammonia injection grid according to an embodiment of the present invention.

Detailed Description

The first embodiment is as follows:

the embodiment is a flue gas denitration high-efficiency regulation and control ammonia injection grid, as shown in fig. 1 and 2. This embodiment is including setting up a plurality of ammonia injection grid unit 3 of detection facility 2 and evenly distributed in the flue of detecting nitrogen oxide in combustion furnace flue 1, ammonia injection grid unit include many and surround and connect the branch pipe 302 of being responsible for 301, the branch pipe on be equipped with a plurality of ammonia injection mouth 303, each ammonia injection grid unit be responsible for and be equipped with governing valve 304 and pressure difference sampling point 305 respectively, each pressure difference sampling point respectively through respective instrument pipe 306 and flue outer can calculate through the pressure difference value that the pressure difference becomes the facility 4 and is connected through each ammonia injection grid unit flue gas flow, pressure difference become the regulation valve information connection of facility and each ammonia injection grid unit.

The principle of the embodiment is as follows: the central position of each ammonia injection grid unit is provided with a pressure difference sampling point, the pressure difference is transmitted to a pressure difference transmitter instrument outside the flue through an instrument guide pipe, the flue gas flow and the nitrogen oxide amount of each ammonia injection grid unit are calculated through the pressure difference value, the ammonia injection amount of each ammonia injection grid is accurately regulated and controlled according to the flue gas flow and the distribution condition of the nitrogen oxide at the section of the flue, and the aim of accurately and uniformly injecting ammonia is fulfilled. The sampled pressure difference is transmitted to a pressure difference transmitter instrument outside the flue through a pressure guide pipe. Each ammonia spraying grid is provided with an independent ammonia gas control valve (regulating valve), and the ammonia spraying amount is controlled by regulating the opening degree of the valves.

The flue illustrated in fig. 1 (indicated by a thick dashed line in fig. 1 and 2) is a horizontal cross-section of a rectangular flue of a combustion furnace, and 12H-shaped ammonia injection grid units are uniformly distributed on one horizontal cross-section of the flue, and in practice, a multi-layer ammonia injection grid may be provided, that is, a plurality of ammonia injection grid units are distributed on a plurality of horizontal cross-sections with different heights, and a certain distance is kept between the horizontal cross-sections, so that ammonia as a catalyst can be sufficiently merged with flue gas.

In order to ensure that the ammonia water can be uniformly sprayed from each nozzle, the main pipe of the ammonia spraying grid unit is arranged at the central part of the ammonia spraying grid unit through the passage, if the branch pipes are distributed in a circle, the main pipe can be arranged at the center of the circle, and if the branch pipes are distributed in an H shape, the main pipe can be arranged at the midpoint position of the short connecting line in the middle of the H shape.

The differential pressure transmitting facility comprises a differential pressure sampling point with two sampling ports, an instrument conduit and a pressure transmitter. Two sampling ports of the sampling points are respectively arranged on a flue gas flowing channel in the front-back sequence of the flue gas flowing direction so as to detect the pressures of two different positions and obtain the difference value between the two pressures. The meter conduits are usually two, and are respectively connected with two sampling ports, and the pressure transmitter can be a universal pressure sensor. In order to prevent dust in the flue gas from blocking the sampling port and the instrument guide pipe, the sampling port can be arranged along the flowing direction of the flue gas, a back-blowing facility is arranged on the instrument guide pipe, and the back-blowing is utilized to blow out the dust which is polluted in the instrument guide pipe and the sampling port from the guide pipe and the sampling port.

And the main pipe of each ammonia spraying grid unit is provided with a regulating valve. The regulating valve can be manually controlled or electrically controlled. When the regulating valve is manual, an operator can read the NOx parameter value of a detection facility for detecting nitrogen oxides and the pressure difference parameter value measured by each pressure difference transmitting facility, obtain the ammonia spraying amount required by each ammonia spraying grid unit through calculation of each pressure difference parameter value and the NOx parameter value, and manually control the regulating valve by the operator so as to reach the ammonia spraying amount of each ammonia spraying grid unit. If the electric control valve is adopted, complete automatic control can be realized, namely, the electric signal output by the pressure transmitting facility is sent to the operation controller, the ammonia injection amount is obtained after calculation by the operation controller, the opening degree of the electric valve is calculated according to the ammonia injection amount, and then the electric valve acts to execute the operation.

The detection facilities for detecting the nitrogen oxides are sensors specially used for detecting the nitrogen oxides in the flue gas, and equipment capable of outputting and displaying parameters measured by the sensors in an electric signal mode, such as CEMS instruments and the like. There are several prior art solutions for how to detect nitrogen oxides in a flue. As in some prior art solutions, NOx is considered to be non-uniform across a section of the flue, so multiple sensors are placed in a plane of the flue to detect NOx. However, in practice, such a detection method is too costly (the CEMS meter is a relatively expensive instrument), and the equipment cost is a large burden. Therefore, the embodiment adopts the measurement of the NOx value of one or a limited number of points in the flue, considers that the NOx in the flue is uniform, and only changes of the NOx value in the same section are generated due to different flue gas flow rates, so that the embodiment can realize accurate control of the ammonia spraying amount by arranging one or a few sensors for measuring the NOx in the flue.

Example two:

this embodiment is an improvement of the first embodiment, and is a refinement of the ammonia injection grid unit of the first embodiment. The ammonia injection grid units described in this embodiment are uniformly distributed in a flue with a rectangular cross section in a grid shape, branch pipes of the ammonia injection grid units are respectively in an H shape, and the pressure difference sampling point is arranged at the midpoint of a middle connecting line of the H shape, as shown in fig. 2.

In the embodiment, each branch pipe of the ammonia injection grid is distributed in an H shape, namely two long pipes on two sides, a short pipe in the middle is connected with the middle point of the two long pipes, and the middle point of the short pipe is provided with a connecting point with a main pipe. Thus, the center of each ammonia injection grid is positioned at the joint of the main pipe and the branch pipe, and therefore, the pressure difference sampling point is arranged at the position, namely the pressure difference sampling point is arranged at the center of each ammonia injection grid unit. Because each ammonia injection grid unit is uniformly distributed in the flue, the pressure difference sampling points are uniformly distributed on the cross section of the flue along with the meshing of each ammonia injection grid.

Example three:

this embodiment is a modification of the above embodiment, and is a refinement of the above embodiment regarding the sampling port of the differential pressure sampling point. The two

sampling ports

3051, 3052 of the differential pressure sampling point described in this embodiment are arranged along the flowing direction of the flue gas, as shown in fig. 3.

For preventing that the smoke and dust from flowing backward and blockking up the sample connection, the design of two equal leeds of sample has been taken to this embodiment. The two sampling ports can be spatially in a straight line or not, but the two sampling ports are always kept in tandem in the flowing direction of the flue gas so as to ensure the pressure difference.

Example four:

this embodiment is a modification of the above-described embodiment, and is a refinement of the above-described embodiment with respect to the meter duct. The instrumentation conduits described in each of the embodiments are provided with blow-back means 5, as shown in fig. 3.

In order to prevent the instrument guide pipe and the sampling port from blocking the differential pressure sampling, an anti-blocking back blowing device can be arranged on the instrument guide pipe, namely, a bifurcated pipe is arranged at the rear end of the instrument guide pipe (if the position where the instrument guide pipe is connected with the sampling port is the front end, the position where the instrument guide pipe is connected with a pressure transmitting facility is the rear end), the bifurcated pipe is used for connecting an air source of compressed air, the compressed air is continuously utilized to perform back blowing (arrow direction in figure 3) in the process of detecting smoke or afterwards, and dust infected in the instrument guide pipe and the sampling port is blown back to a flue so as to keep the instrument guide pipe and the sampling port unblocked.

Example five:

this embodiment is a modification of the above embodiment and is a refinement of the above embodiment with respect to the regulating valve. The regulating valve described in this embodiment is an electrically controlled regulating valve.

The opening of the valve can be conveniently and manually adjusted by using the electric control adjusting valve, and the opening of the valve can also be controlled by using an electronic device so as to realize automatic control.

Example six:

the present embodiment is an improvement of the above embodiment, and is a refinement of the above embodiment regarding the electrically controlled regulating valve. The electric control regulating valve described in this embodiment is connected to an arithmetic controller 6, and the arithmetic controller is connected to the detecting facility for detecting nitrogen oxides and the pressure transmitter, as shown in fig. 4.

The automatic control scheme of the embodiment controls the ammonia spraying amount by using a signal feedback mode. The control process comprises the following steps: the average content of nitrogen oxides in a flue is detected, the flue gas flow passing through each ammonia spraying grid is detected in a pressure difference detection mode, the nitrogen oxide amount passing through each ammonia spraying grid is calculated according to the two parameters, the ammonia spraying amount of each ammonia spraying grid is calculated, the ammonia spraying amount is converted into the opening degree of each regulating valve and executed, and accurate ammonia spraying control amount is achieved.

The operation controller described in this embodiment is an electronic device with calculation and storage capabilities, such as a single chip microcomputer, an industrial PC, and other electronic devices.

Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention and not to limit, although the present invention has been described in detail with reference to the preferred arrangement, it should be understood by those skilled in the art that the technical solution of the present invention (such as the form of ammonia injection grid, the form of adjusting the amount of ammonia injection, etc.) can be modified or replaced equivalently without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. An ammonia injection grid for efficient regulation and control of flue gas denitration comprises a detection facility arranged in a flue of a combustion furnace for detecting nitrogen oxides and a plurality of ammonia injection grid units uniformly distributed in the flue, wherein each ammonia injection grid unit comprises a plurality of branch pipes surrounding and connected with a main pipe, and a plurality of ammonia injection ports are arranged on the branch pipes.

2. The efficient ammonia injection grid as claimed in claim 1, wherein the ammonia injection grid units are uniformly distributed in the flue with rectangular cross section in a grid shape, the branch pipes of the ammonia injection grid units are respectively in an H shape, and the pressure difference sampling point is arranged at the midpoint of the middle connecting line of the H shape.

3. The high efficiency ammonia injection grid as claimed in claim 2, wherein the two sampling ports of the pressure differential sampling point are arranged along the flowing direction of the flue gas.

4. An efficient control ammonia injection grid as claimed in claim 3, wherein each of said instrumentation conduits is provided with blow-back means.

5. The high efficiency adjustable ammonia injection grid as set forth in claim 4, wherein said regulating valve is an electronically controlled regulating valve.

6. The efficient ammonia injection grid as claimed in claim 5, wherein the electrically controlled regulating valve is connected to an arithmetic controller, and the arithmetic controller is connected to the nitrogen oxide detecting device and the pressure transmitter.