A device for single-meter and mixed-meter measurement of denitrification flue gas

Abstract

This utility model discloses a device for single-meter and mixed-meter measurement of denitrification flue gas. It includes multiple sets of sampling pipelines installed on the denitrification flue. These pipelines are arranged sequentially along the flue gas flow direction within the flue and are equally spaced. All pipelines are connected to the same sample gas chamber. A fan is installed on the top wall of the sample gas chamber's inner cavity. The sample gas chamber is connected to a connecting pipe that communicates with its inner cavity, and a NOx analyzer is connected through this connecting pipe. This utility model utilizes multiple sets of sampling pipelines to extract flue gas from different locations within the denitrification flue and, in conjunction with the NOx analyzer, achieves multi-point single-meter monitoring, reducing the cost of multi-point NOx concentration measurement. Furthermore, the equally spaced sampling pipelines facilitate the acquisition of NOx concentration variations within the area. The sample gas chamber and fan ensure thorough mixing of multiple flue gas streams, meeting the requirements for mixed-meter measurement.

Description

Technical Field

[0001] This utility model relates to the field of SCR flue gas denitrification technology, and more specifically, to a single-meter monitoring and mixed-meter measurement device for denitrification flue gas. Background Technology

[0002] Selective catalytic reduction (SCR) flue gas denitrification technology, as a major high-efficiency nitrogen oxide (NOx) control technology, has been widely used in coal-fired power generating units. In recent years, the demand for precise nitrogen injection in denitrification zoned nitrogen injection technology has been increasing. The original monitoring scheme of measuring NOx concentration at a single point on the flue is no longer sufficient to meet the requirements of precise nitrogen injection. Measuring NOx concentration on flues ten meters or wider is too cumbersome due to variations in operating load and differences in the flow field of large flue ducts. Measuring only one point and setting nitrogen injection based on the NOx concentration measured at that point is too coarse, resulting in either wasted nitrogen or insufficient nitrogen injection. On the other hand, deploying too many NOx meters for measurement on large flue ducts increases costs.

[0003] Therefore, a new solution is needed to address the above problems. Utility Model Content

[0004] The purpose of this utility model is to overcome the shortcomings of the prior art and provide a device for single-meter and mixed-meter measurement of denitrification flue gas.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A device for single-meter and mixed-meter measurement of denitrification flue gas includes multiple sets of sampling pipelines installed on the denitrification flue. The multiple sets of sampling pipelines are arranged sequentially along the flue gas flow direction in the denitrification flue and are equally spaced. All the multiple sets of sampling pipelines are connected to the same sample gas box. A fan is installed on the top wall of the inner cavity of the sample gas box. The sample gas box is connected to a connecting pipe that communicates with its inner cavity and is connected to a NOx analyzer through the connecting pipe.

[0007] Furthermore, the sampling pipeline includes a sampling probe, a sampling pump, a sampling tube, and a first solenoid valve. The sampling probe is installed on the denitrification flue, the inlet of the sampling probe is connected to the denitrification flue, the outlet of the sampling probe is connected to one end of the sampling tube, the other end of the sampling tube is connected to the sample gas box, the sampling pump is installed at the sampling tube position where the sampling probe is located, and the first solenoid valve is installed at the sampling tube position where the sample gas box is located.

[0008] Furthermore, a drying module is installed inside the sample gas box, which is used to dry the flue gas extracted from the denitrification flue.

[0009] Furthermore, it also includes a backflushing mechanism, which includes a blower, an air intake pipe, a second solenoid valve, and a third solenoid valve. One end of the air intake pipe is connected to a connecting pipe, and the other end of the air intake pipe is connected to the air outlet of the blower. The second solenoid valve is installed on the air intake pipe, and the third solenoid valve is installed on the side of the connecting pipe away from the air intake pipe.

[0010] The beneficial effects of this utility model are:

[0011] 1. In this utility model, multiple sets of sampling pipelines are set up to extract flue gas from different locations in the denitrification flue, and in conjunction with the NOx analyzer, the effect of single-meter multi-point monitoring is achieved, reducing the cost of multi-point NOx concentration measurement. At the same time, the multiple sets of sampling pipelines are set at equal intervals to obtain the differences in NOx concentration within the area. By setting up a sample gas box and a fan, the multiple flue gases are fully mixed to meet the measurement requirements of mixed measurement. Through the combination of multi-point monitoring and mixed measurement, effective nitrogen injection is achieved, which is suitable for working conditions with relatively stable load, relatively stable coal type, and different but short-term stable flow field.

[0012] 2. In this utility model, a drying module is set in the sample gas box to remove moisture from the flue gas, so as to avoid errors in the measurement data caused by moisture, ensure the accuracy and reliability of the measurement data, and meet the requirements of high-precision measurement.

[0013] 3. In this utility model, by setting up a back-blowing mechanism, a blower is used to blow gas into the air inlet pipe at a pressure higher than the flue gas pressure in the sampling tube, so as to blow the flue gas in the sample gas box and the sampling tube back into the denitrification flue, thereby avoiding or reducing the influence of the residual flue gas in the sample gas box and the sampling tube on the next NOx concentration measurement. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a single-meter patrol and mixed-meter measurement device for denitrification flue gas in this embodiment.

[0015] Figure reference numerals: 1. Denitrification flue; 2. Sampling pipeline; 201. Sampling probe; 202. Sampling pump; 203. Sampling tube; 204. First solenoid valve; 3. Sample gas box; 3. Fan; 301. Drying module; 302. Connecting pipe; 4. NOx analysis table; 5. Backflush mechanism; 6. Blower; 601. Inlet pipe; 602. Second solenoid valve; 603. Third solenoid valve; 604. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Example: A device for single-meter monitoring and mixed-meter measurement of denitrification flue gas, such as... Figure 1 As shown, the system includes multiple sets of sampling pipelines 2 installed on the denitrification flue 1. The multiple sets of sampling pipelines 2 are arranged sequentially along the flue gas flow direction in the denitrification flue 1, and the multiple sets of sampling pipelines 2 are arranged at equal intervals. All of the multiple sets of sampling pipelines 2 are connected to the same sample gas box 3. The sample gas box 3 has an inner cavity, and a fan 301 is installed on the top wall of the inner cavity. The sample gas box 3 is connected to a connecting pipe 4 that communicates with its inner cavity, and a NOx analysis table 5 is connected through the connecting pipe 4.

[0018] The number of sampling pipelines 2 is determined based on the flow field conditions of the denitrification flue 1 (such as flue size, different loads, physical / digital models, and sampling test reports under different operating conditions). During routine testing, sampling pipelines 2 are opened sequentially to extract flue gas from the denitrification flue 1 into a sample gas box 3. The sample gas box 3 is connected to a NOx analyzer 5 via a connecting pipe 4, and the NOx concentration in the flue gas is measured using the NOx analyzer 5. During mixed testing, all sampling pipelines 2 are opened to extract flue gas from different locations in the denitrification flue 1 into the sample gas box 3. The fan 301 in the sample gas box 3 mixes the flue gas from different locations in the denitrification flue 1, and then the NOx concentration in the mixed flue gas is measured using the NOx analyzer 5. It should be noted that during routine testing, when one sampling pipeline 2 is open, the remaining sampling pipelines 2 are closed.

[0019] By setting up multiple sets of sampling pipelines 2, flue gas from different locations in the denitrification flue duct 1 can be extracted and used in conjunction with the NOx analysis table 5 to achieve the effect of multi-point monitoring with a single table, reducing the cost of multi-point NOx concentration measurement. At the same time, the multiple sets of sampling pipelines 2 are set at equal intervals to obtain the differences in NOx concentration within the area. By setting up a sample gas box 3 and a fan 301, the multiple flue gases can be fully mixed to meet the measurement requirements of mixed measurement. Through the combination of multi-point monitoring and mixed measurement, effective nitrogen injection can be achieved.

[0020] Furthermore, each sampling pipeline 2 includes a sampling probe 201, a sampling pump 202, a sampling tube 203, and a first solenoid valve 204. The sampling probe 201 is installed on the denitrification flue 1, the inlet of the sampling probe 201 is connected to the denitrification flue 1, the outlet of the sampling probe 201 is connected to one end of the sampling tube 203, the other end of the sampling tube 203 is connected to the sample gas box 3, the sampling pump 202 is installed on the sampling tube 203 at the position of the sampling probe 201, and the first solenoid valve 204 is installed on the sampling tube 203 at the position of the sample gas box 3.

[0021] In use, the first solenoid valve 204 and the sampling pump 202 are turned on. The sampling pump 202 is used to extract the flue gas in the denitrification flue 1 into the sample gas box 3. The NOx concentration in the flue gas is measured using the NOx analysis table 5.

[0022] Furthermore, a drying module 302 is installed inside the sample gas chamber 3. The drying module 302 is used to dry the flue gas extracted from the denitrification flue duct 1. The drying module 302 removes moisture from the flue gas to avoid errors in the measurement data caused by moisture, ensuring the accuracy and reliability of the measurement data and meeting the requirements of high-precision measurement. Preferably, the drying module 302 can be installed inside the sample gas chamber 3, located at the connection between the sample gas chamber 3 and the sampling tube 203, so as to dry the flue gas extracted into the sample gas chamber 3 immediately. The drying module 302 does not affect the flow of flue gas while drying it, that is, it does not affect the flow of flue gas between the sampling tube 203 and the sample gas chamber 3. The drying module 302 can be a drying box containing a desiccant or a dryer.

[0023] Furthermore, the measuring device also includes a backflushing mechanism 6, which includes a blower 601, an air inlet pipe 602, a second solenoid valve 603, and a third solenoid valve 604. One end of the air inlet pipe 602 is connected to the connecting pipe 4, and the other end of the air inlet pipe 602 is connected to the air outlet of the blower 601. The air inlet of the blower 601 is connected to an air source. The second solenoid valve 603 is installed on the air inlet pipe 602, and the third solenoid valve 604 is installed on the side of the connecting pipe 4 away from the air inlet pipe 602.

[0024] In use, the second solenoid valve 603 is opened, connecting the inlet pipe 602 to the connecting pipe 4; the third solenoid valve 604 is closed, cutting off the connection between the connecting pipe 4 and the NOx analyzer 5; the first solenoid valve 204 is opened, connecting the sampling pipe 203; and the sampling pump 202 is closed. Then, the blower 601 is turned on, blowing gas into the inlet pipe 602 at a pressure higher than the flue gas pressure in the sampling pipe 203, blowing the flue gas in the sample gas box 3 and the sampling pipe 203 back into the denitrification flue duct 1, so as to avoid or reduce the influence of the residual flue gas in the sample gas box 3 and the sampling pipe 203 on the next NOx concentration measurement.

[0025] Preferably, the gas source can be a gas that will not cause errors in the NOx analysis data in Table 5.

[0026] Preferably, the sampling pump 202 can be a diaphragm pump, model N86KNE or N86KTE. The diaphragm pump draws the flue gas from the denitrification flue duct 1 into the sample gas box 3. Simultaneously, when the diaphragm pump stops operating, the blower 601 pumps gas into the inlet pipe 602 at a pressure higher than the flue gas pressure in the sampling pipe 203, creating a pressure difference between the sampling pipes 203 on both sides of the diaphragm pump. The flue gas and other gases then flow back into the denitrification flue duct 1 via the diaphragm pump. It should be noted that no check valve is installed at the outlet of the diaphragm pump to ensure that the flue gas can flow back.

[0027] like Figure 1 As shown, the process of measuring NOx concentration using the above-mentioned device is as follows:

[0028] During the survey, sampling pump 202 and the first solenoid valve 204 at measuring point 1 are first turned on. Sampling pump 202 and the first solenoid valve 204 at the remaining measuring points are turned off, the second solenoid valve 603 is turned off, and the third solenoid valve 604 is turned on. The flue gas in the denitrification flue 1 is drawn into the sample gas box 3 by sampling pump 202, and the NOx concentration in the flue gas is measured using NOx analysis table 5. After the measurement is completed, sampling pump 202 and the third solenoid valve 604 are turned off, and blower 601 and the second solenoid valve 603 are turned on. Blower 601 is used to blow the flue gas remaining in the sample gas box 3 and sampling pipe 203 back into the denitrification flue 1. During the NOx concentration measurement stage, sampling pump 202 is turned on continuously until the end. During the measurement completion stage, blower 601 is turned on continuously until the end.

[0029] After the measurement at measuring point 1 is completed, the sampling pump 202 and the first solenoid valve 204 at measuring point 2 are turned on. The sampling pump 202 and the first solenoid valve 204 at measuring point 1 and the remaining measuring points are turned off. The second solenoid valve 603 is turned off and the third solenoid valve 604 is turned on. The measurement and blowing process at measuring point 1 are repeated. This process is repeated in a loop.

[0030] During the mixed test, all sampling pumps 202 and the first solenoid valve 204 at all measuring points are turned on, the second solenoid valve 603 is closed, and the third solenoid valve 604 is turned on. The flue gas from different locations in the denitrification flue duct 1 is drawn together into the sample gas box 3 by all sampling pumps 202. The fan 301 in the sample gas box 3 blows air to fully mix all the flue gas. The NOx concentration in the mixed flue gas is measured using NOx analysis table 5. After the measurement is completed, all sampling pumps 202 and the third solenoid valve 604 are turned off, and the blower 601 and the second solenoid valve 603 are turned on. The blower 601 blows the flue gas remaining in the sample gas box 3 and all sampling tubes 203 back into the denitrification flue duct 1. During the NOx concentration measurement stage, the sampling pumps 202 are turned on continuously until the end. During the measurement completion stage, the blower 601 is turned on continuously until the end.

[0031] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A device for single-pipe and mixed-pipe measurement of denitration flue gas, comprising a plurality of groups of sampling pipelines (2) installed on a denitration flue (1), characterized in that, Multiple sets of sampling pipelines (2) are arranged sequentially along the flue gas flow direction in the denitrification flue (1), and the multiple sets of sampling pipelines (2) are arranged at equal intervals. All sets of sampling pipelines (2) are connected to the same sample gas box (3). A fan (301) is installed on the top wall of the inner cavity of the sample gas box (3). The sample gas box (3) is connected to a connecting pipe (4) that communicates with its inner cavity, and a NOx analysis table (5) is connected through the connecting pipe (4).

2. The denitrification flue gas single-meter patrol and mixed-meter measurement device according to claim 1, characterized in that, The sampling pipeline (2) includes a sampling probe (201), a sampling pump (202), a sampling tube (203), and a first solenoid valve (204). The sampling probe (201) is installed on the denitrification flue (1). The inlet of the sampling probe (201) is connected to the denitrification flue (1). The outlet of the sampling probe (201) is connected to one end of the sampling tube (203). The other end of the sampling tube (203) is connected to the sample gas box (3). The sampling pump (202) is installed at the sampling tube (203) located at the sampling probe (201). The first solenoid valve (204) is installed at the sampling tube (203) located at the sample gas box (3).

3. The denitrification flue gas single-meter patrol and mixed-meter measurement device according to claim 1, characterized in that, The sample gas box (3) is equipped with a drying module (302), which is used to dry the flue gas extracted from the denitrification flue (1).

4. The denitrification flue gas single-meter patrol and mixed-meter measurement device according to claim 1, characterized in that, It also includes a backflushing mechanism (6), which includes a blower (601), an air inlet pipe (602), a second solenoid valve (603) and a third solenoid valve (604). One end of the air inlet pipe (602) is connected to the connecting pipe (4), and the other end of the air inlet pipe (602) is connected to the air outlet of the blower (601). The second solenoid valve (603) is installed on the air inlet pipe (602), and the third solenoid valve (604) is installed on the side of the connecting pipe (4) away from the air inlet pipe (602).

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