CN212363811U - Flue gas measurement sampler and apparatus - Google Patents

Abstract

The utility model provides a sampler and flue gas measuring equipment are measured to flue gas. The flue gas measurement sampler comprises a rotary sampling shaft, a first buffer chamber with a gas inlet and a second buffer chamber with a sample gas outlet, wherein the rotary sampling shaft is arranged in an inner cavity of a sampling arm and a shaft body, a sampling port on the sampling arm is in fluid communication with a shaft body gas outlet port on the shaft body, and the rotary sampling arm receives gas from the gas inlet and sends the gas to the sample gas outlet through the inner cavity. The utility model discloses can detect the subregion of a plurality of flues' pollutant in succession, device operational reliability is high, and then effectively avoid spouting ammonia excessively.

Description

Flue gas measurement sampler and apparatus

Technical Field

The utility model relates to a flue gas denitration field, in particular to flue gas measurement sampler and flue gas measurement equipment.

Background

At present, Selective Catalytic Reduction (SCR) flue gas denitration technology is taken as a main high-efficiency Nitrogen Oxide (NO)_x) Control techniques are widely used in flue gas treatment of, for example, coal-fired power generating units. For this purpose, ammonia is sprayed into the flue gas upstream of the SCR reactor. However, in operation, ammonia injection excess is prevalent. On the one hand, when faced with complicated peak regulation pressure and coal quality current situation, thermal power unit operating condition is changeable and unstable, has caused the unstability of boundary conditions such as SCR entry speed field, concentration field for it needs to satisfy the worst operating mode of pollutant to spout ammonia volume. On the other hand, higher standards are continuously provided for pollutant emission, and the ammonia spraying amount is also increased. The problem is particularly prominent in the thermal power industry in China, because the peak regulation pressure in China is high, the coal quality change is large, and the ultra-low emission modification standard that the pollutant emission index is far better than the foreign level is also met, compared with the foreign state, the denitration SCR device faces worse inlet conditions and higher-requirement outlet conditions. The ammonia injection excess phenomenon finally causes the differential pressure of downstream equipment to increase, and even influences the loading capacity of a unit and the operation safety of the unit. In order to develop the potential of the denitration SCR device and reduce ammonia consumption, a technical scheme of zoned fine ammonia injection control is adopted. The partition refined ammonia spraying control technical scheme is thatThe feasible scheme with high cost performance divides a large flue into a plurality of smaller flue subareas, and ammonia injection control is carried out on each subarea by detecting the NOx emission amount of each flue subarea.

To obtain NOx values for each stack sector, a large number of stations need to be added. There are generally two approaches. One is to adopt a method of synchronous measurement of a plurality of sets of measurement systems, so that a plurality of groups of continuous data can be obtained, the timeliness of the data is good, but the cost is high. Since it is necessary to use the same number of CEMS measurement systems as the number of partitions, the cost is rapidly increased in proportion when the number of partitions is increased. The other method is a round-robin measurement method, and one analyzer is matched with a plurality of sets of sampling devices to perform measurement. Typically, switching is performed by using a switching valve installed on a pipeline of each zone, so that the measurement sample gas of each zone can enter the analyzer for measurement in time sequence. Compared with a synchronous measurement method, the method has lower cost, but has the problems of long time of a single path, easy blockage of a pipeline (no sample gas flows and dust can be deposited when the measurement is not carried out), easy failure of a switching valve (the switching valve works in a high-temperature and high-dust environment) and the like.

In the field of gas pollutant measurement, rotary sampling devices have been proposed to achieve flue gas selection in different sampling areas. For example, patent application CN108254581A discloses a multi-point automatic sampling and testing system for gaseous pollutants, which includes a rotary automatic switching device. The rotary automatic sampling device specifically comprises a fixed end and a rotary selection end, wherein a plurality of sample gas pipeline interfaces on the fixed end are connected with a plurality of sampling probes arranged in a flue through sample gas pipelines, and the rotary selection end is provided with a sample gas selection interface. When the rotating end rotates, the sample gas selecting interface rotates along with the rotating end, so that sample gases from different sample gas pipeline interfaces are led out.

There remains a need for an improved smoke measurement sampling device.

SUMMERY OF THE UTILITY MODEL

In one aspect, the present invention provides a smoke measurement sampler, comprising:

a rotary sampling shaft including a shaft body, a sampling arm extending from the shaft body away from an axis of the shaft body, and a sampling port on the sampling arm, and having a lumen in the sampling arm and the shaft body that fluidly communicates the sampling port to a shaft body vent port on the shaft body;

a first buffer chamber surrounding the sampling arm, having a plurality of gas inlets distributed on a circle around an axis of the rotary sampling shaft, and having a gas outlet; and

a second buffer chamber surrounding the shaft body gas outlet port and having a sample gas outlet,

wherein the sampling port is configured to receive gas from the plurality of gas inlets, respectively, as the rotating sampling shaft rotates.

Preferably, the rotary sampling shaft is driven by a variable frequency motor.

Preferably, the number of the air inlets is 2-20.

In another aspect, the present invention provides a flue gas measuring apparatus, comprising:

a plurality of flue gas inlets disposed in the flue;

the above flue gas measurement sampler, wherein the gas inlet of the flue gas measurement sampler is connected to the flue gas inlet through a flue gas pipe; and

a gas analyzer connected to a sample gas outlet of the flue gas measurement sampler.

Preferably, the flue gas measuring apparatus further comprises:

an air outlet pipe connecting the air outlet to an air preheater outlet.

Preferably, the flue gas measuring apparatus further comprises:

a standard gas source; and

a standard gas inlet conduit connecting the standard gas source to one of the plurality of gas inlets.

Preferably, the flue gas measuring apparatus further comprises:

a controller configured to control rotation of the rotary sampling shaft in accordance with analysis data of the gas analyzer.

The smoke measuring sampler of the utility model arranges the rotary sampling shaft in the first buffer chamber, and has no rotary shell, thereby needing no rotary sealing surface, and improving the running reliability of the device; through setting up hollow rotatory sample axle and second surge chamber, solved the sample position of removal and fixed flue gas analyzer's the problem of being connected. Correspondingly, the utility model discloses a flue gas measuring equipment can be reliably continuous automatic measure in the flue the pollutant level of each subregion. And then, adopt the utility model discloses an equipment carries out SCR flue gas denitration can effectively avoid spraying ammonia excessively.

Drawings

FIG. 1 is a schematic diagram of one embodiment of a smoke measurement sampler.

Figure 2 is a schematic view of the surfaces of the buffer chamber in one embodiment,

fig. 3 is a schematic diagram of another embodiment of a smoke measurement sampler.

FIG. 4 is a schematic diagram of one embodiment of a flue gas measurement device.

Fig. 5 is a schematic diagram of the results of gas analysis.

Fig. 6 is a schematic diagram of an embodiment of the present invention.

Detailed Description

The related art provides a rotary automatic sampling device for analyzing smoke pollutants. This automatic sampling device of rotation type adopts fixed shell and rotatory shell cooperation to set up the appearance gas export on rotatory shell, select with carrying out appearance gas. However, do not rely on any theory, the utility model discloses a utility model people discovers that this leads to the rotary seal face between stiff end and rotatory selection end too big, centers on whole device periphery, both causes the gas leakage of rotary seal face easily, leads to the rotary seal face card stopper again easily. Further, in the case where the sample gas selection port is provided on the rotation selection end of the housing on the apparatus side, it is problematic how to stably connect the sample gas analyzer with the rotation position thereof being changed. In fact, the rotary automatic switching device cannot be effectively connected with rotating equipment.

The utility model provides a sampler is measured to flue gas, it can solve above-mentioned problem.

In one embodiment, the utility model discloses a flue gas measurement sampler contains:

a rotary sampling shaft including a shaft body, a sampling arm extending from the shaft body away from an axis of the shaft body, and a sampling port on the sampling arm, and having a lumen in the sampling arm and the shaft body that fluidly communicates the sampling port to a shaft body vent port on the shaft body;

a first buffer chamber surrounding the sampling arm, having a plurality of gas inlets distributed on a circle around an axis of the rotary sampling shaft, and having a gas outlet; and

a second buffer chamber surrounding the shaft body gas outlet port and having a sample gas outlet,

wherein the sampling port is configured to receive gas from the plurality of gas inlets, respectively, as the rotating sampling shaft rotates.

The smoke measurement probe includes a first buffer chamber as a main body. The first buffer chamber is used to receive flue gas sample gases from different regions in the flue and to support the rotating sampling shaft and to house the sampling arm described below. Typically, it has a fixed housing that does not itself have a rotating portion. The first buffer chamber has an aperture for receiving the shaft body of the rotary sampling shaft and has a plurality of air inlets distributed in a circular ring about its axis. The air inlet communicates the inside and the outside of the first buffer chamber, and the openings of the air inlet in the first buffer chamber are distributed on a circular ring around the axis of the rotary sampling shaft. These inlets may be in fluid communication with flue gas inlets provided in different sections of the flue through sample gas ducts outside the first buffer chamber. Thereby, the flue gases from the individual flue sections can enter the first buffer chamber from different inlet openings, respectively, and they leave the inlet openings in the above-mentioned ring area. The air inlet may simply be a through hole in the wall of the first buffer chamber. More preferably, the air inlet may have a portion directed towards the airway extending within the first buffer chamber to enhance the directionality of smoke passing through the air inlet. The air inlet area of the air inlet can be properly adjusted according to the requirement, and the air inlet can also be provided with a horn-shaped inlet with the area gradually reduced, so that the smoke in a larger cross-sectional area is gathered and enters to play a role in concentrating the smoke so as to be introduced into a sampling port described below.

The gas inlets are distributed in a circular ring area around the axis, which is aligned with the rotational movement path of the sampling opening on the sampling arm of the rotary sampling shaft described below. Therefore, when the sampling arm rotates to the corresponding position, the sampling port can receive the gas from the gas inlet. Thus, as the rotating sampling shaft rotates, gas from the plurality of gas inlets is sequentially received by the rotating sampling ports. The flue gas received by the air inlet at the position where the sampling port is not turned is left in the first buffer chamber and is not used for flue gas analysis.

The first buffer chamber also has an air outlet for the exit of said fumes not used for analysis. By the embodiments described below connected to the outlet of the air preheater (air preheater), the air outlet can efficiently discharge flue gas not used for analysis without a pumping device.

The rotating sampling shaft is one of the core components of a smoke measurement sampler, which can be rotated about an axis to take smoke sample gases from different areas in a flue. To this end, the rotary sampling shaft includes a shaft body, a sampling arm extending radially from the shaft body, and a sampling port on the sampling arm, and the rotary sampling shaft has a lumen in the sampling arm and the shaft body that fluidly communicates the sampling port to a shaft body vent port on the shaft body. Thus, gas can enter from the sampling port, pass through the inner cavity and reach the shaft body gas outlet port.

When the rotary sampling shaft rotates, the sampling arm rotates in the first buffer chamber. The sampling arm is provided with a sampling port. The sampling ports may be aligned with different gas inlets during rotation. Therefore, when the sampling arm rotates, the sampling port can rotate along the circular ring area around the axis, and the flue gas sample gas sent by the gas inlet at any position in the circular ring area is obtained. The sampling opening in the sampling arm can be fitted air-tightly with the air inlet of the first buffer chamber when rotated into position, but also not strictly air-tightly when the analysis result is not greatly affected.

There is no particular requirement for the shape of the sampling arm. Which extends from the shaft body away from the axis of the shaft body to ensure that the sampling port is at a certain radius from the axis. The particular sampling arm may be straight or curved; may be extended in the radial direction or may be inclined. In other words, the sampling arm is used for connecting the sampling opening and the shaft body and ensuring that the rotation track of the sampling opening is circular.

The sampling arm is of single-arm form. For the purpose of rotational force balancing, balancing arms may be provided at axisymmetric positions. The balance arm is not provided with a gas passage communicated with the cavity, so that the sampling of the sampling arm is not influenced. However, the balance arm may have a through hole to facilitate the gas flow in the first buffer chamber.

In order to send the sample gas that obtains different positions to same position, the utility model designs an inner chamber of rotatory sample axle. The lumen extends through the sampling arm and shaft body. By utilizing the inner cavity, no matter the sampling arm and the sampling port on the sampling arm are positioned at any position, the flue gas sample gas obtained by the sampling port can be discharged from the shaft body gas outlet port on the shaft body. The shaft body air outlet port is matched with a second buffer chamber, so that the flue gas sample gas can be discharged from the fixed position of the sampler, and the effective connection with a flue gas analyzer is realized.

The air outlet port of the shaft body is arranged on the shaft body. Preferably on the shaft body side wall, but may also be at the end of the shaft body. Because the shaft body also rotates along with the sampling arm, the air outlet port of the shaft body moves. It is therefore still difficult to communicate the shaft outlet port directly to an analyzer outside the flue through a fixed line. The utility model designs another surge chamber to solve the problem. The buffer chamber surrounds the shaft body air outlet port and is provided with a sample gas outlet. Thus, sample gas taken from the outlet port of the moving shaft first enters the buffer chamber and then can flow out of the flue through the fixed pipeline from the fixed sample gas outlet of the buffer chamber.

For the purpose of distinction from the first buffer chamber, this buffer chamber is referred to as a second buffer chamber. The shape of the second buffer chamber may be arbitrary. It can be a sealed shell that the axle body passes through, makes the gas that axle body outlet port discharged can only further be discharged from the sample gas export, and this sealed shell does not influence axle body rotation simultaneously.

The flue gas measuring sampler of the utility model realizes sampling by the rotary sampling arm in the first buffer chamber, and the phenomena of air leakage and blocking are not easy to occur without using a rotary shell; the effective connection of the movable sampling part and the fixed gas analyzer is realized by designing the inner cavity of the rotary sampling arm and the second buffer chamber.

Figure 1 shows one embodiment of a smoke measurement sampler. The flue gas measurement sampler includes: a rotary sampling shaft 10, the rotary sampling shaft 10 comprising a shaft body 101, a sampling arm 102 extending radially from the shaft body, and a sampling port 103 on the sampling arm 102, and the rotary sampling shaft having a lumen 105 in the sampling arm 102 and the shaft body 101, the lumen 105 fluidly connecting the sampling port 103 to a shaft body vent port 104 on the shaft body; a first buffer chamber 20, the first buffer chamber 20 enclosing the sampling arm 102, having a plurality of gas inlets 2001, 2002 distributed on a circle around the axis of the rotary sampling shaft, and having a gas outlet 202; and a second buffer chamber 30, the second buffer chamber 30 surrounding the shaft body gas outlet port 104 and having a sample gas outlet 301, wherein the sampling port 103 sequentially receives gas from the plurality of gas inlets 2001, 2002 as the rotary sampling shaft 10 rotates.

FIG. 1 is a cross-sectional view taken along the axial direction of a rotary sampling shaft. The sampling arm 102 can be rotated along an axis out of the plane of the paper or in the plane of the paper. The first buffer chamber 20 has a plurality of air inlets thereon, and air inlets 2001 and 2002 are shown in the drawing. The first buffer chamber may have a plurality of air inlets distributed on a circular ring about the axis of the rotary sampling shaft. Figure 2 illustrates one embodiment of the first buffer chamber showing a schematic view of the surface of the buffer chamber with four air inlets 2001-2004.

As the rotating sampling shaft rotates, the sampling ports may be aligned with different gas inlets and receive gas therefrom. For example, when the rotary sampling shaft in FIG. 1 is rotated 180, the sampling port will be rotated to the right opposite the gas inlet 2002 and receive gas therefrom.

In fig. 1, the gas inlet 2001 and sampling port 103 are depicted as sealless docked. However, the two may also be sealingly abutting, for example by providing a sealing felt or gasket at the end of the two. In fig. 1, the gas inlet 2001 and the sampling port are depicted as having the same dimensions. However, the two may also have different dimensions. In fig. 1, the inlet 2001 has a small section of air duct 2001a inside the first buffer chamber. However, such an airway tube may not be present. In fig. 1, the gas-guide tube 2001a is parallel to the rotation axis, so that the gas inlet 2001 is at the same distance from the rotation axis as the sampling port 103. However, it is also possible to design the air duct 2001a to be inclined toward the rotation axis so that the distance between the sampling port 103 and the rotation axis is smaller than the distance between the opening of the air inlet 2001 at the housing and the rotation axis, in order to appropriately shorten the length of the sampling arm. In fig. 1, the airway tube 2001a is depicted as cylindrical, but may also be a constricted flare shape to focus the gas.

The number of air inlets may be arbitrary. Preferably, the number of air inlets is 2 to 20 for a corresponding number of measurement zones. When the number of the air inlets exceeds 20, since a certain time is required for sampling at each air inlet, a period of one rotation is long, and it is disadvantageous in obtaining real-time data. Preferably, the gas inlets are evenly distributed along the circle, facilitating control of the alignment of the sampling arm therewith.

Sample gas entering from the sample port passes through cavity 105 to shaft body outlet port 104. The cavity in fig. 1 is depicted as being concentric with the sampling arm and shaft body. However, the cavity may be shaped in any shape as long as fluid communication is possible. Preferably, the cavity has smooth inner walls and no corners formed, thereby facilitating gas flow and reducing dead corners that may cause gas stagnation and dust accumulation.

In FIG. 1, axle body outlet port 104 is disposed on an axle body sidewall, but may be disposed at, for example, an end of the axle body. In the embodiment of fig. 1, there is only one shaft outlet port, but it is also possible to design a plurality of shaft outlet ports, all of which open into the second buffer chamber.

The second buffer chamber 30 surrounds the shaft body air outlet port so that air discharged from the shaft body air outlet port can enter the second buffer chamber. In the embodiment of fig. 1, the shaft body 101 penetrates the wall of the second buffer chamber 30, is rotatable, and is airtight at the penetration. The end of the shaft body may also be arranged in the second buffer chamber.

The second buffer chamber has a sample gas outlet 301. The sample gas outlet will communicate with a gas analyzer.

As shown in FIG. 3, the rotary sampling shaft may also have a balance arm 106 and may have a through hole 107 for gas to flow through.

Returning to fig. 1, the first buffer chamber 20 has an air outlet 202. Gas that does not enter the sampling port 103, such as the gas entering from the gas inlet 2002 in the figure, is then exhausted from the gas outlet 202. A negative pressure may be applied at the air outlet to cause undetected flue gas to exit the first buffer chamber and may accelerate the flow of flue gas into the first buffer chamber.

The smoke measuring sampler of the utility model arranges the rotary sampling shaft in the first buffer chamber, eliminates the peripheral rotary sealing surface caused by the rotary shell, and improves the running reliability of the device; through setting up hollow rotatory sample axle and second surge chamber, solved the sample position of removal and fixed flue gas analyzer's the problem of being connected. Correspondingly, the utility model discloses a flue gas measuring equipment can be reliably continuous automatic measure in the flue the pollutant level of each subregion. And then, adopt the utility model discloses an equipment carries out SCR flue gas denitration can effectively avoid spraying ammonia excessively.

In one embodiment, the rotary sampling shaft is driven by a variable frequency motor. The variable frequency motor has the advantages that the rotation speed can be flexibly regulated, and the rotation period can be adjusted. This is particularly advantageous in controlling the sampling in dependence on the analysis result.

The utility model also provides a flue gas measuring equipment, it contains:

a plurality of flue gas inlets disposed in the flue;

in the flue gas measuring and sampling device, the gas inlet of the flue gas measuring and sampling device is connected to the flue gas inlet through a flue gas pipeline; and

a gas analyzer connected to a sample gas outlet of the flue gas measurement sampler.

The utility model discloses a flue gas measuring equipment uses the utility model discloses a flue gas measurement sampler is in order to realize measuring in turn to the advantage that has this flue gas measurement sampler.

In one embodiment, the flue gas measurement apparatus further comprises an air outlet duct connecting the air outlet to the air preheater outlet.

Connecting an air outlet to an air preheater outlet may maintain a flow of gas in the first buffer chamber using a pressure differential caused by the air preheater outlet connected to the air outlet. Generally, flue gas in a flue is led to an air preheater after being subjected to SCR denitration, so as to fully utilize residual heat energy in the flue gas. The air preheater may be located at a suitable location in the flue upstream of the SCR reactor. And the flue gas from the denitration outlet reaches the inlet of the air preheater and is discharged from the outlet of the air preheater after passing through the air preheater. The utility model discloses a flue gas measuring equipment has got some in the flue gas from the flue gas entry, and remaining most flue gas is as above accesss to the air heater entry conventionally and is used for preheating. And the air outlet of the smoke measuring sampler is communicated with the outlet of the air preheater. Generally speaking, because air heater's resistance exists, the pressure of air heater export can be less than the utility model discloses the sampling position commonly used is pressure 1 ~ 2 kilopascals in denitration exit promptly. This allows the flow of flue gas in the flue gas measurement probe to be achieved without the use of additional pumping means to draw the sample gas, but instead using the pressure differential described above. Furthermore, flue gas that does not pass to the gas analyzer can be returned to the bulk of the flue gas and subsequently exhausted together, for example through a stack. Of course, the utility model discloses also can utilize solitary aspiration pump to connect the gas outlet of flue gas measurement sampler in order to extract unnecessary appearance gas.

In the present invention, the connection of the gas circuit may be direct or indirect. Typically, the connection is realized by a pipeline, and conventional devices such as a valve, a pump and the like can be added on the pipeline appropriately.

In one embodiment, the flue gas measurement apparatus further comprises

A standard gas source; and

a standard gas inlet conduit connecting the standard gas source to one of the plurality of gas inlets.

The standard gas is a gas as a standard for calibration, and its composition and concentration of each component are known. Hereinafter, the concentration of the contaminant component of interest therein is sometimes referred to as "the concentration of the sample gas" or "the concentration of the standard gas". By connecting one inlet to the standard gas inlet duct, the analyzer can be periodically supplied with standard gas for data processing, calibration and position characterization. Specifically, when the gas analyzer detects the standard gas component, it can be stated that the gas inlet to which the sampling port of the rotary arm is directed is connected to the gas inlet of the standard gas source through the standard gas inlet pipe. Thereby, the rotational parameters of the rotary sampling arm, such as period and position, can be calibrated based on the data of the gas analyzer.

Fig. 4 shows an exemplary embodiment of a flue gas measuring device according to the present invention. The denitrated flue gas advances along the pipeline, and a part leads to a plurality of air inlets of flue gas measurement sampler through a plurality of flue gas pipelines c (3 are drawn schematically in the figure), and the rest most flue gas leads to the air heater entry along main pipeline e. The gas outlet of the flue gas measuring sampler is connected to the outlet of the air preheater through a pipeline a. The sample gas obtained by the sampler is connected to a gas analyzer outside the flue through a pipeline b. The standard gas source provides standard gas to one gas inlet of the smoke measuring sampler through a pipeline d. The data from the gas analyzer is transmitted to a controller, and the controller can control the rotation of the rotating sampling shaft in the flue gas measuring sampler, and optionally also can control the gas outlet parameters of the target gas source and other operating parameters.

Only one conduit b is shown in fig. 4 connected to one gas analyzer. However, the conduit b may also be manifolded outside the flue and connected to a plurality of gas analyzers for measuring different components or contaminants. For example, the sample gas is sent to a nitrogen oxide analyzer, a carbon monoxide analyzer, an oxygen analyzer, and the like, respectively.

The smoke measuring method using the smoke measuring equipment comprises the following steps: rotating a rotating sampling shaft of the smoke measurement sampler so that sampling ports respectively receive gas from a plurality of gas inlets; sending the received gas to a gas analyzer through the inner cavity, the shaft body gas outlet port, the second buffer chamber and the sample gas outlet; and analyzing the received gas using a gas analyzer. Preferably, the gas flow in the first buffer chamber is maintained by a pressure difference caused by an outlet of the air preheater connected to the air outlet. Preferably, the standard gas is continuously introduced into one of the plurality of gas inlets; and calibrating, such as positioning the rotating arm, using a calibration gas. Preferably, the rotation of the rotary sampling shaft is controlled based on the analysis data of the gas analyzer.

Fig. 5 is a graph schematically showing the results of four-cycle analysis of the gas at four inlets, one of which is fed with the standard gas, in the case of the standard gas. In the figure, the ordinate is the contaminant concentration and the abscissa is time. The highest black bar represents the concentration in the standard gas and each of the other colors represents the concentration of the sample gas for one inlet port. The results of measurements taken at three sampling locations with the flue gas measuring device of the present invention are schematically shown in fig. 5. After sample gas and a standard gas at three positions are measured in sequence, a cycle is completed, and the next cycle is started. Further analysis can be performed based on the results. For example, the results of a sampling location can be extracted from the map, and the concentration change at that location tracked.

It can be seen that the analyser can calibrate the result once each time the sampling arm is rotated to the air inlet where the calibration gas is located. In other words, the concentration of the standard gas is determined to be constant or vary little, although the concentration of the flue gas sample gas varies in each cycle.

The use of a standard gas is advantageous in several respects.

On the one hand, the gas analyzer and the smoke measuring probe can be periodically checked for proper operation by measuring the concentration of the standard gas. If the standard gas concentration changes suddenly, the user can be prompted to check whether the gas analyzer has errors or whether the smoke measuring sampler has flow path blockage and other problems.

On the other hand, parameters such as a rotation period can be easily obtained by measuring the concentration of the standard gas, and the corresponding relation between the analysis data and the intake air region can be further determined.

Typically, the rotary sampling shaft is controlled to rotate by a variable frequency motor or the like. In this case, it is difficult to intuitively set parameters such as the rotation period. By using a standard gas, the rotation period can be estimated from the analysis data.

For example, the rotation period may be calibrated before the formal analysis is performed. The air mark passage is opened, the rotary sampling shaft is rotated in a certain mode, and a time function C (t) of the concentration is recorded by a gas analyzer. C (t) represents the concentration measured at time t. It should be noted that the time t here may be a period of time. For example, C (0-10 seconds) represents the average of the concentrations measured when the rotating shaft stays at one position during 0-10 seconds.

The first two rotation periods can be taken and when C (t) ═ C is examined₀In which C is₀Is the standard gas concentration. Then, if C is measured twice₀The time difference is T, and T is the time of the rotation period.

For example, C (0-10 seconds) and C (40-50 seconds) are both C₀Then, the time T for receiving the flue gas sample gas is 40 seconds. At the same time, t can be adjusted₀The 80 th second is used as the starting time of the measurement.

After the time T is known, the subsequent data can be distributed to each flue gas inlet according to the number of the flue gas sample gas inlets N. For example, if there are 3 flue gas sample inlets, then it can be determined that from t₀At the beginning of the ith period, the concentration of the mth flue gas sample gas inlet should be C (t)₀+(i-1)*T+T*[m-m+1]and/N). For example, following the example above, the concentration at the 2 nd flue gas inlet during the 3 rd cycle should be C (80s + (3-1) × 40s +40s (2-3)/4), i.e., C (180s-190 s).

The above is but one example of using a standard gas to determine the rotation period and thus assign the measurement values. Other ways of measuring the dispensing measurement with a standard gas may also be used by those skilled in the art.

On the other hand, the use of a standard gas also ensures that possible temporal or spatial errors after each revolution are eliminated.

Although the controller can control the measurement period by controlling the rotational speed of the frequency converter, temporal or spatial errors may occur during the control, resulting in a mismatch between the predicted rotational position and the measurement data. As the number of cycles of operation continues to increase, the accumulation of errors may result in a significant mismatch between the data and the corresponding locations. Furthermore, when using variable frequency motor drives, the rotation period is also variable. It is therefore advantageous to insert standard measuring points during the measurement. The measurement position location can be finally determined by the inserted standard measuring points.

Since the standard gas data can be clearly distinguished in the continuous data, a standard gas source can be connected to one gas inlet, so that the time when the rotating arm reaches the position of the gas inlet every week can be directly known from the data, and error accumulation is avoided.

On this basis, data can be directly assigned to the respective areas. The specific distribution mode is that the period of one rotation of the sampling arm of the rotary sampling shaft is between two adjacent measurement to the standard gas value. The measurements during this period can then be evenly distributed to the individual inlets. In other words, t may not be fixed from t as in the above method₀Time is assigned to the measurement value, but the measurement value is dynamically assigned on a per-time basis.

For example, there are three flue gas inlets in the flue region and are connected to gas inlets 2001 and 2003, respectively, shown in FIG. 2, while gas inlet 2004 is connected to a source of the target gas. Ideally, for example, the rotary arm stays at each gas inlet for 10 seconds, and the average of the gas analyzer measurements during this 10 seconds is taken as the gas inlet data, and then every 10 seconds from the start of the measurement is taken as the data of one gas inlet. However, since there may be some time or space error in the control, for example, 40 seconds, each week is not necessarily the standard, without calibration and correction, the corresponding relationship between the measured value and the air inlet may not be known accurately after a plurality of cycles.

However, since 2004 is connected to the source of the calibration gas, the measurement data can be redistributed after each cycle has begun, i.e., time errors do not accumulate in the measurements of the next cycle. Because the air inlets are uniformly distributed along the circumference, the data curves between two adjacent groups of standard gas data can be averagely distributed to the flue subareas where the flue gas inlets corresponding to the air inlets 2001, 2002 and 2003 are positioned, thereby avoiding the multi-period accumulation of the measured data.

The rotation period may be determined first. For example, the time t when the standard gas data changes suddenly to the smoke data is recorded first₁Then, the time point t of the mutation from the next standard gas data to the smoke data is recorded₂Thereby obtaining the time difference T. The time difference T is the time taken by the sampling arm to rotate for one circle. Subsequently, the time in the period T is divided into N time periods equally by the number N of the air inlets, and the data in each time period T/N corresponds to the data of each air inlet. After a plurality of cycles, no accumulation of errors occurs.

The other mode is that the time point t of the sudden change from the standard gas data to the smoke data is firstly recorded₁Then, recording the time point t when the next flue gas data changes to the standard gas data₂And obtaining the time difference P. The time difference is the time taken for the sampling arm to pass through all the flue gas sample gas inlets. Then, dividing the time in the time P into N-1 time periods according to the number N-1 of the air inlets for introducing the flue gas, and the data in each time period P/(N-1) correspond to the data of each air inlet. After a plurality of cycles, no accumulation of errors occurs.

Furthermore, even if the rotation parameters are changed, for example by means of an inverter motor, so that they become no longer 10 seconds per inlet opening, the measurement data can be easily assigned to the respective flue section.

Other methods can also be used to process data according to the calibrated position of the standard gas inlet. For example, the time of the rotary arm from one air inlet to the next may be taken into account and the relevant measurements removed. In addition, when the rotation of the rotary sampling shaft can be controlled accurately enough without error accumulation, the period length can be accurately calibrated only by using the standard gas, and the data of the subsequent period can be calculated according to the period length.

In fig. 5, each column may be an average of continuous measurement curves taken while staying at one air inlet during one rotation period. Of course, it is also possible to measure a plurality of discrete points, for example one measurement value per second.

The flue gas measurement device also comprises a controller. The controller is configured to control the motor frequency based on the analysis data of the gas analyzer to control rotation of the rotary sampling shaft to adjust the rotation period. In addition, the controller is operative to control the gas flow parameters of the target gas source. In addition, the controller can also integrate the functions of data processing, analyzer calibration, pipeline positioning of each area and the like. Of course, separate processors may be used to perform the above functions.

The gas analyzer collects flue gas composition data that varies over time. These data are attributed to different flue segments according to the method described previously. The data may then be filtered, averaged, etc. The composition status of each flue segment can be obtained.

The standard gas inlet can also be used for calibrating a gas analyzer. Analyzers generally employ optical principles. During the use of the optical element, some systematic deviation can occur, and finally, the measured data is subjected to drift distortion. Therefore, the analyzer needs to be calibrated regularly to ensure the accuracy of the data. The gas analyzer can automatically finish data correction according to the concentration and the measured concentration of the standard gas label. Although can set up the mark gas device that is used for demarcating gas analysis appearance alone, preferably, through the utility model discloses a mark gas air inlet can accomplish gas analysis appearance simultaneously and mark and the swinging boom location.

The smoke measuring method using the smoke measuring equipment comprises the following steps:

rotating the rotating sampling shaft of the smoke measurement sampler such that the sampling ports receive gas from the plurality of gas inlets, respectively;

sending the received gas to the gas analyzer through the inner cavity, the shaft body gas outlet port, the second buffer chamber and the sample gas outlet; and

measuring the received gas using the gas analyzer.

As described above, the flow of gas in the first buffer chamber can be maintained by using the pressure difference caused by the outlet of the air preheater connected to the air outlet. The standard gas can be continuously introduced into one of the plurality of gas inlets; and when the rotary sampling shaft rotates, positioning the rotation of the rotary sampling shaft by monitoring the position of the air inlet through which the standard gas passes.

The rotation of the rotary sampling shaft may be controlled based on analysis data of the gas analyzer. When the numerical fluctuation is large, the rotation speed of the rotary sampling shaft can be increased, namely, the sampling period is shortened, so that data can be obtained more quickly, the processes of ammonia injection and the like which are described below can be adjusted more frequently, and smoke pollutants can be controlled. Conversely, when the numerical fluctuation is small, a longer sampling period can be maintained, and unnecessary operations can be reduced accordingly.

The following examples are used to further illustrate the present invention.

Examples

In a rectangular flue downstream of the SCR reactor, three flue gas inlets are arranged side by side for monitoring contaminants in three flue sections. The number of the air inlets of the smoke measuring sampler is 4, wherein 3 air inlets are connected to a smoke inlet through a smoke pipeline, and one air inlet is connected to a standard gas source. Standard gas source providing 100mg/m NOx concentration³The gas of (2). The air outlet of the flue gas measuring sampler is connected to the outlet of the air preheater. The inlet of the air preheater is connected to the flue.

The sample gas will flow naturally as the pressure in the outlet flue of the air preheater is lower than the flue downstream of the SCR reactor. The analyzer analyzes and measures the NOx component in the sample gas.

Fig. 6 schematically shows the logical relationship of the respective components in this embodiment. The upper part of the figure shows a cross section of the flue, three of which are indicated by dashed lines. A flue gas inlet (indicated by a circle) is provided in each section and the flue gas is passed to a sampler. The sampler is in gas connection with a standard gas source and an analyzer. The controller is simultaneously connected to the sampler, the source of the target gas and the analyzer, and obtains data from the analyzer and is used to control the operation of the sampler and the source of the target gas.

The sampler was started to rotate for a period of 40 seconds, with a sample port dwell time of 10 seconds at each air inlet.

The data period of the analyzer may be 1 second, and in order to correspond to the sample port residence time, the data for 10 consecutive seconds are averaged to obtain the measured value for each zone.

In this example, the analyzer processes NO for a period of time_xConcentration data are (in mg/m)³): 40. 40, 80, 100, 35, 45, 78, 98, 30, 50, 75, 100. Each data represents the case of one inlet, for a total of three cycles. After the distribution, the concentration data of the first area is obtained as follows: 40. 35, 30; the concentration data of the second region were: 40. 45, 48; the concentration data of the third region are: 80. 78, 75. The measured concentration data of the standard gas are 100, 98 and 100.

Emission control target is 50mg/m³Thus, the first zone NOx concentration is relatively small and is further reduced, which indicates that the ammonia injection amount of the corresponding first flue section in the upstream of the SCR is relatively large, and the ammonia injection amount needs to be reduced; the NOx concentration of the second region is also smaller, but gradually increases to be near 50, and the ammonia injection amount of the region does not need to be adjusted; the NOx concentration in the third region is higher and the reduction rate is slower, which means that the ammonia injection amount in the region is lower, and the ammonia injection amount in the region needs to be increased appropriately.

In this way, the adjustment of the ammonia injection amount is carried out in real time, so that the NOx concentration of each region downstream of the SCR can be stabilized at a set value of 50mg/m³And nearby, realizing fine partition adjustment. It can be seen that the utility model discloses can detect the partitioned pollutant of a plurality of flues in succession, device operational reliability is high, and then effectively avoid spouting ammonia excessively.

Note that the standard gas concentration is 100mg/m³Can be more than 50mg/m of emission control target³. This is because the total amount of the standard gas is small and does not substantially affect the environment.

It will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments of the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (7)

1. A smoke measurement sampler, comprising:

a rotary sampling shaft including a shaft body, a sampling arm extending from the shaft body away from an axis of the shaft body, and a sampling port on the sampling arm, and having a lumen in the sampling arm and the shaft body that fluidly communicates the sampling port to a shaft body vent port on the shaft body;

a first buffer chamber surrounding the sampling arm, having a plurality of gas inlets distributed on a circle around an axis of the rotary sampling shaft, and having a gas outlet; and

a second buffer chamber surrounding the shaft body gas outlet port and having a sample gas outlet,

wherein the sampling port is configured to receive gas from the plurality of gas inlets, respectively, as the rotating sampling shaft rotates.

2. A smoke measurement sampler according to claim 1,

the rotary sampling shaft is driven by a variable frequency motor.

3. A smoke measurement sampler according to claim 1,

the number of the air inlets is 2-20.

4. A flue gas measurement apparatus, comprising:

a plurality of flue gas inlets disposed in the flue;

the smoke measurement sampler of claim 1 wherein an air inlet of the smoke measurement sampler is connected to the smoke inlet by a smoke conduit; and

a gas analyzer connected to a sample gas outlet of the flue gas measurement sampler.

5. The flue gas measurement apparatus of claim 4, further comprising:

an air outlet pipe connecting the air outlet to an air preheater outlet.

6. The flue gas measurement apparatus of claim 4, further comprising:

a standard gas source; and

a standard gas inlet conduit connecting the standard gas source to one of the plurality of gas inlets.

7. The flue gas measurement apparatus of claim 4, further comprising:

a controller configured to control rotation of the rotary sampling shaft in accordance with analysis data of the gas analyzer.

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