CN115046814A - Dust meter-based constant-speed sampling device and method - Google Patents

Abstract

The invention discloses a constant-speed sampling device and method based on a dust meter, and relates to the technical field of thermal engineering automation; the device comprises a controller, a sampling pipeline (1), a fan (2), a dust meter probe (3), an adjusting valve (4) and a flow meter (5), wherein one end of the sampling pipeline (1) is connected and conducted with a flue (7), the other end of the sampling pipeline (1) is connected and conducted with the flue (7), the fan (2), the dust meter probe (3) and the adjusting valve (4) are arranged on the sampling pipeline (1), and the flow meter (5) is arranged on the flue (7); the method comprises a detection step, wherein a controller obtains the actual flow velocity of the flue gas of a flow velocity meter, obtains the sampling flow velocity of a dust meter probe, and adjusts the opening of an adjusting valve according to the actual flow velocity of the flue gas to enable the sampling flow velocity to be close to and equal to the actual flow velocity of the flue gas, so that the dust value sent by the dust meter probe is obtained; the flue gas measurement is accurate through the regulating valve, the flow velocity meter used for measuring the flow velocity of the flue gas in the flue and the like.

Description

Device and method for isokinetic sampling based on dust meter

technical field

The invention relates to the technical field of thermal automation, in particular to an isokinetic sampling device and method based on a dust meter.

Background technique

According to Clause 5.4.1.8 of "Technical Requirements and Testing Methods for Continuous Monitoring System for Flue Gas (SO2, NOX, Particulate Matter) Emissions from Fixed Pollution Sources" [HJ76-2017], "Particulate matter CEMS adopting extraction measurement method shall have an automatic sampling device. The isokinetic tracking sampling function of adjusting the sampling flow rate by tracking the change of flue gas flow rate, the isokinetic tracking suction error should not exceed ±8%”, so it is necessary to add a flow adjustment device to the dust meter, introduce the chimney inlet flow rate into the dust meter, and modify the dust meter program to make it meet the isokinetic sampling requirements.

The retrieval formula is TACD_ALL: (smoke gas AND dust meter AND isokinetic AND (tracking OR sampling)), and a relatively close prior art solution is obtained as follows.

The authorization announcement number is CN 207881767 U, and the name is multi-point sampling integrated CEMS system. It includes a sampling pipe, a static pressure pipe, a dynamic pressure pipe, a cleaning rod and a sampling nozzle arranged in the flue. The cleaning rod is movably connected in the dynamic pressure pipe. The sampling nozzle is arranged on the sampling pipe; the number of sampling nozzles on the sampling pipe is not less than one, the sampling device realizes multi-point sampling, the installation position is not required, and the cleaning rod swings in the dynamic pressure pipe The purpose of cleaning can be achieved.

The authorization announcement number is CN 207096046 U, and the name is a low-concentration particulate matter measuring instrument suitable for wet flue gas. It includes a cabinet, a sampling probe with heating, a test cavity, a low-concentration dust meter sensor and a jet pump. The sampling probe with heating is arranged in the flue, and the sampling probe with heating is connected to the test cavity in the cabinet through a heating pipeline. , the test cavity is provided with a heating module, the low-concentration dust meter sensor is set on the test cavity, and is used to measure the concentration of flue gas particles collected in the test cavity, and the jet pump is set on the bottom side of the inside of the cabinet. It is used to draw the flue gas collected by the heated sampling probe into the test chamber.

The authorization announcement number is CN 210720075 U, and the name is a flue gas flow velocity monitoring dust meter for isokinetic sampling. It includes a display instrument, a monitoring box and a flue, one side of the display instrument is electrically connected to the top of the monitoring box through wires, and the bottom of the inner cavity of the monitoring box is fixedly connected with a variable frequency suction fan through a support plate, and the variable frequency suction fan One side of the air intake pipe is connected with an air intake pipe, and the end of the air intake pipe away from the variable frequency suction fan runs through the monitoring box and the flue in turn and extends to the inner cavity of the flue. Cleaning the dust on the inner wall of the monitoring box ensures the normal operation of the measuring unit, greatly improves the accuracy of the monitoring dust meter data, avoids the impact of the dust on the inner wall of the monitoring box on the detection results, and increases the overall use to a certain extent. Long life, strong practicability, convenient for users to clean the collection box.

Combining the above-mentioned three patent documents and the existing technical solutions, the inventor finds that the following technical problems exist in the existing technical solutions.

The multi-point sampling integrated CEMS system mainly solves the technical problem of representative sampling, which is different from the technical problem to be solved by this application. In addition, due to the unreasonable distribution of various equipment, there is a technical problem of inaccurate measurement.

In a low-concentration particulate matter measuring instrument suitable for wet flue gas, due to the unreasonable distribution of various equipment and the existence of heating technical means, there is an obvious deviation between the parameters to be measured after heating and the original measured parameters in the flue, resulting in Technical issues with inaccurate measurements.

In a flue gas flow rate monitoring dust meter for isokinetic sampling, the variable frequency suction fan is arranged in the inner cavity of the monitoring box, and the end of the intake pipe away from the variable frequency suction fan runs through the monitoring box and the flue in turn and extends to the inner cavity of the flue. The equipment distribution is unreasonable, and there are technical problems of inaccurate measurement.

Existing technical problems and thinking:

How to solve the technical problem of inaccurate flue gas measurement, that is, how to make the deviation between the sampling flow rate V1 and the actual flow rate V2 of the flue gas within 8%.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide an isokinetic sampling device and method based on a dust meter to solve the technical problem of inaccurate flue gas measurement.

In order to solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a constant velocity sampling device based on a dust meter includes a controller, a sampling pipeline, a fan and a dust meter, and the dust meter includes a dust meter probe and a measuring unit, It also includes a regulating valve and a flow meter for measuring the flow rate of flue gas in the flue. One end of the sampling pipeline is connected to the flue, and the other end of the sampling pipeline is connected to the flue, so that the flue gas in the flue is connected. It enters the sampling pipeline from one end of the sampling pipeline, and flows back to the flue from the other end of the sampling pipeline. The fan and the dust detector probe are arranged in the sampling pipeline. The regulating valve is arranged on the sampling pipeline. The meter is arranged in the flue, the dust meter probe is connected and communicated with the measuring unit, and the controller is connected and communicated with the measuring unit, the fan, the regulating valve and the flow meter respectively.

A further technical solution is: a detection module is also included, and the detection module is a program module, which is used by the controller to obtain the actual flow rate of the flue gas sent by the flow meter, obtain the sampling flow rate sent by the dust meter probe, and adjust the regulating valve according to the actual flow rate of the flue gas. The opening degree is so that the sampling flow rate is close to and equal to the actual flow rate of the flue gas, and the dust value sent by the dust meter probe is obtained as the accurate dust value measured by the dust meter.

A further technical solution is as follows: a connecting piece is further included, the connecting piece is arranged on the surface of the flue, the flow meter is fixedly connected with the connecting piece, and the flow meter extends into the flue.

A further technical solution is that: the fan is a jet fan, the controller is a control cabinet, and the regulating valve is an electric regulating valve.

A method for isokinetic sampling based on a dust meter, based on the above device, comprising the following steps, a detection step, a controller obtains the actual flow rate of flue gas sent by a flow meter, obtains the sampling flow rate sent by a dust meter probe, and according to the actual flow rate of the flue gas Adjust the opening of the regulating valve so that the sampling flow rate is close to and equal to the actual flow rate of the flue gas, and the dust value sent by the dust meter probe is obtained as the accurate dust value measured by the dust meter.

An isokinetic sampling device based on a dust meter includes a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the above-mentioned corresponding steps when executing the computer program.

An isokinetic sampling device based on a dust meter includes a computer-readable storage medium storing a computer program, and the computer program implements the above-mentioned corresponding steps when executed by a processor.

The beneficial effects produced by the above technical solutions are:

An isokinetic sampling device based on a dust meter includes a controller, a sampling pipeline, a fan and a dust meter, the dust meter includes a dust meter probe and a measuring unit, and also includes a regulating valve and a flow rate for measuring the flow rate of flue gas in a flue. One end of the sampling pipeline is connected to the flue, and the other end of the sampling pipeline is connected to the flue, so that the flue gas in the flue enters the sampling pipeline from one end of the sampling pipeline, and flows from the sampling pipeline. The other end flows back to the flue, the fan and the dust meter probe are arranged in the sampling pipeline, the regulating valve is arranged on the sampling pipeline, the flow meter is arranged in the flue, and the dust meter probe is connected to the measuring unit The controller is connected and communicated with the measuring unit, the fan, the regulating valve and the flow meter respectively. According to the technical solution, accurate flue gas measurement is realized by adjusting the valve and the flow meter for measuring the flue gas flow rate in the flue.

A method for isokinetic sampling based on a dust meter, based on the above device, comprising the following steps, a detection step, a controller obtains the actual flow rate of flue gas sent by a flow meter, obtains the sampling flow rate sent by a dust meter probe, and according to the actual flow rate of the flue gas Adjust the opening of the regulating valve so that the sampling flow rate is close to and equal to the actual flow rate of the flue gas, and the dust value sent by the dust meter probe is obtained as the accurate dust value measured by the dust meter. According to the technical solution, accurate flue gas measurement is achieved through detection steps and the like.

For details, please refer to the description in the detailed description.

Description of drawings

1 is a structural diagram of Embodiment 1 of the present invention;

Fig. 2 is the principle block diagram of Embodiment 1 of the present invention;

Fig. 3 is the principle block diagram of Embodiment 3 of the present invention;

Fig. 4 is the principle block diagram of Embodiment 4 of the present invention;

Figure 5 is a data flow diagram of the present invention.

Among them: 1 sampling pipeline, 2 fan, 3 dust meter probe, 4 regulating valve, 5 flow meter, 6 connecting piece, 7 flue.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

In the following description, many specific details are set forth to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can do so without departing from the connotation of the present application Similar promotion, therefore, the present application is not limited by the specific embodiments disclosed below.

Example 1:

As shown in FIG. 1 and FIG. 2 , the present invention discloses an isokinetic sampling device based on a dust meter, which includes a controller, a sampling pipeline 1, a fan 2, a dust meter, a regulating valve 4, and is used to measure the smoke in the flue 7. The flow meter 5 and the connector 6 of the air flow rate and the detection module, the dust meter includes the dust meter probe 3 and the measuring unit, the fan 2 is a jet fan, the controller is a control cabinet, and the regulating valve 4 is an electric motor regulating valve.

As shown in FIG. 1 , one end of the sampling pipeline 1 is connected to the flue 7 and the other end of the sampling pipeline 1 is connected to the flue 7 , so that the flue gas in the flue 7 is discharged from the sampling pipeline 1 . One end of the pipe enters the sampling pipe 1, and flows back to the flue 7 from the other end of the sampling pipe 1.

As shown in FIG. 1 , the fan 2 and the dust detector probe 3 are fixed in the sampling pipeline 1, the regulating valve 4 is fixed on the sampling pipeline 1, and the connecting piece 6 is fixed on the surface of the flue 7, The flow meter 5 is fixedly connected with the connecting piece 6 , and the flow meter 5 extends into the flue 7 .

As shown in FIG. 2 , the dust meter probe 3 is electrically connected to the measurement unit and communicates unidirectionally, the measurement unit is electrically connected to the controller and communicates unidirectionally, and the flow meter 5 is electrically connected to the controller and communicates unidirectionally , the controller is electrically connected with the fan 2 and communicates in one way, and the controller is electrically connected with the regulating valve 4 and communicates in one way.

The detection module is a program module, which is used by the controller to obtain the actual flow velocity V2 of the flue gas sent by the flow meter 5, obtain the sampling flow velocity V1 sent by the dust meter probe 3, and adjust the opening of the regulating valve 4 according to the actual flow velocity V2 of the flue gas, so that The sampling flow rate V1 is close to and equal to the actual flow rate V2 of the flue gas, and the dust value sent by the dust meter probe 3 is obtained as the accurate dust value measured by the dust meter.

Among them, the controller, the fan, the dust meter probe, the measuring unit, the regulating valve, the flow meter itself, and the corresponding communication connection technology are the prior art and will not be repeated here.

The main inventive idea is to make the flue gas in the sampling pipeline match the actual situation in the flue as much as possible, so as to improve the measurement accuracy of the system.

In the sampling pipeline, the dust meter probe is set in the sampling pipeline, and the measuring unit is placed outside the sampling pipeline, so as to make the flue gas in the sampling pipeline match the actual situation in the flue as far as possible.

Among them, the dust meter probe 3 uses a probe that can detect both the sampling flow rate V1 and the dust value, or use a probe that can detect and obtain the dust value, add a flow meter next to the probe and connect and communicate with the controller.

Example 2:

The present invention discloses a method for isokinetic sampling based on a dust meter. Based on the device of Embodiment 1, the method includes the following steps:

Detection steps

The controller obtains the actual flow velocity V2 of the flue gas sent by the flow meter 5, obtains the sampling flow velocity V1 sent by the dust meter probe 3, and adjusts the opening of the regulating valve 4 according to the actual flow velocity V2 of the flue gas, so that the sampling flow velocity V1 is close to and equal to the flue gas. The actual flow rate V2, the dust value sent by the dust meter probe 3 is obtained as the accurate dust value measured by the dust meter.

Example 3:

As shown in FIG. 3 , the present invention discloses a dust meter-based isokinetic sampling device including a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the computer program when the processor executes the computer program. Procedure of Example 2.

Example 4:

As shown in FIG. 4 , the present invention discloses a computer-readable storage medium, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in Embodiment 2 are implemented.

Example 5:

Embodiment 5 is different from Embodiment 1 in that the regulating valve 4 is a pneumatic valve, that is, a pneumatic regulating door or a pneumatic regulating door.

The invention discloses a constant velocity sampling device based on a dust meter, comprising a controller, a sampling pipeline 1, a fan 2, a dust meter, a regulating valve 4, a flow meter 5 for measuring the flow rate of flue gas in a flue 7, and a connecting piece 6 and a detection module, the dust meter includes a dust meter probe 3 and a measurement unit, the fan 2 is a jet fan, the controller is a control cabinet, and the regulating valve 4 is a pneumatic valve.

One end of the sampling pipeline 1 is connected to the flue 7, and the other end of the sampling pipeline 1 is connected to the flue 7, so that the flue gas in the flue 7 enters the sampling pipeline from one end of the sampling pipeline 1. 1. Flow back to the flue 7 from the other end of the sampling pipe 1 .

The fan 2 and the dust meter probe 3 are fixed in the sampling pipeline 1, the regulating valve 4 is fixed on the sampling pipeline 1, the connecting piece 6 is fixed on the surface of the flue 7, and the flow meter 5 is connected to the sampling pipeline 1. The connecting piece 6 is fixedly connected, and the flow meter 5 extends into the flue 7 .

The dust meter probe 3 is electrically connected to the measurement unit and communicates unidirectionally, the measurement unit is electrically connected to the controller and communicates unidirectionally, the flow meter 5 is electrically connected to the controller and communicates unidirectionally, and the controller communicates with the controller. The fan 2 is electrically connected and communicated in one way, and the controller is electrically connected with the regulating valve 4 and communicated in one way.

The detection module is a program module, which is used by the controller to obtain the actual flow velocity V2 of the flue gas sent by the flow meter 5, obtain the sampling flow velocity V1 sent by the dust meter probe 3, and adjust the opening of the regulating valve 4 according to the actual flow velocity V2 of the flue gas, so that The sampling flow rate V1 is close to and equal to the actual flow rate V2 of the flue gas, and the dust value sent by the dust meter probe 3 is obtained as the accurate dust value measured by the dust meter.

Among them, the controller, the fan, the dust meter probe, the measuring unit, the regulating valve, the flow meter itself, and the corresponding communication connection technology are the prior art and will not be repeated here.

The idea of this application:

The main purpose is to make the flue gas measured in the reaction chamber of the dust meter match the actual situation in the flue, so as to improve the measurement accuracy of the system.

work process:

As shown in Figure 5, the flue gas in the flue is collected and sent to the dust meter probe. The dust meter probe measures the dust content in the flue gas. After the measurement is completed, the flue gas is still discharged back to the flue gas, and the dust content is transmitted to the controller at the same time. . Because the power of the jet fan is constant, the sampling flow rate V1 is constant. Due to the real-time change of the actual flow rate V2 of the flue gas, the measurement deviation of the dust meter is large.

Improvement: add a flue gas flow rate measuring device, namely flow meter 5, to measure the actual flow rate V2 of flue gas in the flue (real-time change), add a jet fan control valve, and transmit the two flow rate signals to the controller through the control cable, and the controller adjusts and controls through PID The jet fan adjusts the valve opening to change the sampling flow velocity V1, and finally achieve the purpose of isokinetic tracking, so that the deviation of the two flow velocity signals is within 8%, and the dust value measured by the dust meter is accurate.

Specific construction plan:

1. Add 1 set of flow adjustment device to the sampling pipes of the clean flue gas and dust meter of No. 1 to 6 units, and lay the power cable and control cable of the flow adjustment device to the PLC control cabinet of the dust meter.

2. Upgrade the PLC controller of the dust meter, increase the PLC flow rate receiving channel and the flow control valve control channel, and modify the control logic to realize the isokinetic sampling function.

3. Lay the clean flue gas and dust meter to the desulfurization DCS system, and lead the net flue gas flow rate signal to the PLC system of the clean flue gas and dust meter to control the opening of the flow regulating valve to ensure that the sampling flow is consistent with the flue gas flow and meets the requirements, etc. The speed tracking attraction error does not exceed the standard requirement of ±8%.

After the application has been run confidentially for a period of time, the benefits of feedback from on-site technicians are:

After adding the sampling device to the dust meter, the accuracy of the measurement data has been greatly improved, ensuring that through environmental inspection and data comparison work, the economic loss and environmental protection public opinion pressure caused by the measurement accuracy problem to the power plant can be avoided.

It includes a controller, a sampling pipeline, a fan, a dust meter, a regulating valve and a flow meter for measuring the flow rate of flue gas in the flue. The dust meter includes a dust meter probe and a measuring unit, and one end of the sampling pipeline is connected to the flue. , the other end of the sampling pipeline is connected to the flue, the fan, the dust meter probe and the regulating valve are set on the sampling pipeline, the flow meter is set on the flue, the dust meter probe is connected and communicated with the measurement unit, and the controller is respectively connected with the measurement The unit, the fan, the regulating valve and the flow meter are connected and communicated; including the detection step, the controller obtains the actual flow rate of the flue gas sent by the flow meter, obtains the sampling flow rate sent by the dust meter probe, and adjusts the opening of the regulating valve according to the actual flow rate of the flue gas. The sampling flow rate is close to and equal to the actual flow rate of the flue gas, and the dust value sent by the dust meter probe is obtained as the accurate dust value measured by the dust meter. To achieve accurate flue gas measurement.

At present, the technical solution of the present invention has undergone a pilot test, that is, a small-scale test of the product before mass production; after the pilot test is completed, a user usage survey has been carried out in a small area, and the survey results show that the user satisfaction is high ; Now it has begun to prepare for the formal production of the product for industrialization (including intellectual property risk early warning research).

Claims (7)

1. an isokinetic sampling device based on a dust meter, comprising a controller, a sampling pipeline (1), a fan (2) and a dust meter, the dust meter comprising a dust meter probe (3) and a measuring unit, it is characterized in that : also includes a regulating valve (4) and a flow meter (5) for measuring the flow rate of flue gas in the flue gas (7), one end of the sampling pipe (1) is connected to the flue (7), and the sampling pipe The other end of the pipeline (1) is connected to the flue (7), so that the flue gas in the flue (7) enters the sampling pipeline (1) from one end of the sampling pipeline (1), and flows from the sampling pipeline (1). ) flows back to the flue (7), the fan (2) and the dust meter probe (3) are arranged in the sampling pipeline (1), and the regulating valve (4) is arranged in the sampling pipeline (1) Above, the flow meter (5) is arranged in the flue (7), the dust meter probe (3) is connected and communicated with the measuring unit, and the controller is respectively connected with the measuring unit, the fan (2), the regulating valve ( 4) Connect and communicate with the flow meter (5). 2. the isokinetic sampling device based on dust meter according to claim 1, is characterized in that: also comprises detection module, and detection module is a program module, and is used for controller to obtain the actual flow rate of flue gas that flow meter (5) sends V2, obtain the sampling flow rate V1 sent by the dust meter probe (3), adjust the opening of the regulating valve (4) according to the actual flow rate V2 of the flue gas, so that the sampling flow rate V1 is close to and equal to the actual flow rate V2 of the flue gas, and obtain the dust meter probe ( 3) The sent dust value is used as the accurate dust value measured by the dust meter. 3. The isokinetic sampling device based on a dust meter according to claim 1, characterized in that it further comprises a connecting piece (6), wherein the connecting piece (6) is arranged on the surface of the flue (7), and the The flow meter (5) is fixedly connected with the connecting piece (6), and the flow meter (5) extends into the flue (7). 4. The isokinetic sampling device based on a dust meter according to claim 1, characterized in that: the fan (2) is a jet fan, the controller is a control cabinet, and the regulating valve (4) is an electric adjustment valve. 5. a kind of isokinetic sampling method based on dust meter, it is characterized in that: based on the device of claim 1, comprise the steps, detection step, controller obtains the actual flow velocity V2 of flue gas that flow meter (5) sends, obtains dust According to the sampling flow rate V1 sent by the instrument probe (3), adjust the opening of the regulating valve (4) according to the actual flow rate V2 of the flue gas, so that the sampling flow rate V1 is close to and equal to the actual flow rate V2 of the flue gas, and obtain the data sent by the dust instrument probe (3). The dust value is used as the accurate dust value measured by the dust meter. 6. an isokinetic sampling device based on a dust meter, comprising a memory, a processor and a computer program stored in the memory and running on the processor, characterized in that: when the processor executes the computer program, claim 5 is realized in the corresponding steps. 7. An isokinetic sampling device based on a dust meter, comprising a computer-readable storage medium, wherein the computer-readable storage medium is stored with a computer program, characterized in that: when the computer program is executed by a processor, the implementation of claim 5 corresponding steps.

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