CN114199815A - High-temperature infrared flue gas analysis method - Google Patents
High-temperature infrared flue gas analysis method Download PDFInfo
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Abstract
The invention provides a high-temperature infrared flue gas analysis method, which belongs to the technical field of gas analysis and comprises the following steps: connecting a high-temperature infrared flue gas analyzer, high-temperature sampling equipment and a computer, and starting after the computer is powered on; the high-temperature infrared flue gas analyzer and the sampling device enter a preheating standby stage, and the instrument is continuously swept by ambient air in the preheating standby stage; the method comprises the following steps that a sample gas to be detected enters a measuring pool of a high-temperature infrared flue gas analyzer through a sampling device and a sampling device integrated in the high-temperature infrared flue gas analyzer to be subjected to gas concentration measurement and data result storage; after the measurement is finished, the high-temperature infrared smoke gas analyzer is turned off through the computer operation, and in the turning-off process of the high-temperature infrared smoke gas analyzer, the high-temperature infrared smoke gas analyzer continuously extracts ambient air to purge the high-temperature infrared smoke gas analyzer; and (3) data processing and analysis, wherein measured value data stored during measurement is exported through a computer, and the on-site smoke emission condition is analyzed.
Description
Technical Field
The invention provides a high-temperature infrared flue gas analysis method, and belongs to the technical field of gas analysis.
Background
The steel industry is a process-specific heavy polluting enterprise, and the sintering process of the steel industry produces a variety of atmospheric pollutants, such as COx, SOx, NOx, HCL, NH3, N2O, and hydrocarbons. At present, the online or portable pretreatment heating and then testing in an analyzer method are mainly adopted for the emission in the steel industry at abroad, while the standard and detection technology for fixed pollution sources at home are relatively laggard, and most of the methods are laboratory methods, the loss in the sampling process is inevitable, the detection equipment mainly adopts electrochemical and cold NDIR methods, but the cross interference among gases cannot be eliminated, so that the detection data of pollutants are not accurate, and the detection of special pollutant factors is not perfect.
Most analyzers in the market at present adopt an infrared technical principle for analysis, H2O has a relatively wide absorption peak in an infrared spectrum, so that H2O has cross interference on all pollutants basically, while ordinary analyzers in a cold infrared technology are limited by a detector, and the temperature must be reduced to remove H2O, and the H2O cannot be removed by 100% in the process of removing the H2O by a condenser in the market at present, so that the interference of the residual H2O on other pollutants cannot be distinguished. Meanwhile, the loss of SO2 and NOx in the low-temperature sampling process under the high-humidity condition exists, particularly the problem of excessive ammonia emission during wet desulphurization, and the problems of cross interference and the like caused by ammonia concentration detection, excessive ammonia and SO2 and NOx dissolution reaction under the conditions of low temperature and high humidity exist; excessive ammonia is discharged (liquid drop pollutants are in the flue, and the outside of the flue forms ammonia nitrogen sulfur crystal salt), and the environment is polluted again after the sunlight is directly irradiated and gasified.
Disclosure of Invention
The invention provides a high-temperature infrared flue gas analysis method, which is used for solving the problems of process loss, secondary reaction, poor precision measurement and cross interference caused by sample gas sampling because sample gas must be cooled and dewatered in the conventional infrared analysis method, and adopts the following technical scheme:
a high temperature infrared flue gas analysis method, the method comprising:
step 4, after the measurement is finished, the high-temperature infrared smoke gas analyzer is turned off through the computer operation, in the turning-off process of the high-temperature infrared smoke gas analyzer, the high-temperature infrared smoke gas analyzer continuously extracts ambient air to purge the high-temperature infrared smoke gas analyzer until the display of the high-temperature infrared smoke gas analyzer displays that the countdown is stopped, and then the power is cut off to detach and store the high-temperature infrared smoke gas analyzer;
and 5, data processing and analysis, wherein measured value data stored during measurement is exported through a computer, the on-site smoke emission condition is subjected to accurate data measurement and analysis, and the on-site combustion or chemical reaction condition is analyzed through the smoke emission condition, so that the process is adjusted to achieve the purposes of energy conservation, emission reduction and process optimization.
Further, step 3 the sample gas that awaits measuring passes through with the high temperature sampling equipment that high temperature infrared flue gas analyzer is connected, and the inside integrated high temperature sampling device of high temperature infrared flue gas analyzer, process high temperature infrared flue gas analyzer's optical path system gets into in high temperature measurement cell of high temperature infrared flue gas analyzer includes:
301, enabling the infrared light beam to enter a measuring cell through a light ray inlet of the measuring cell;
step 302, the infrared light beams are respectively and directly irradiated onto the side wall of a first spherical mirror, and the first spherical mirror is arranged in parallel to the bottom surface of the measuring cell;
step 303, reflecting the infrared light beams to a second spherical mirror through the first spherical mirror, and reflecting the infrared light beams to a curved mirror surface on the first spherical mirror through the second spherical mirror; the second spherical mirror is arranged at the bottom of the measuring cell and close to a light ray inlet;
step 304, reflecting the infrared light beam to a third spherical mirror through a curved mirror surface on the first spherical mirror; after the infrared light beam reaches the specified measurement absorption optical path through continuous reflection, the infrared light beam is reflected by a third spherical mirror to be emitted from a light ray outlet of the measurement cell; the third spherical mirror is arranged at the bottom of the measuring cell and close to a light ray outlet;
and 305, directly enabling the infrared light beam emitted from the light ray outlet to enter a detection device, and obtaining a measurement data value of the concentration of the measurement gas in real time through the detection device.
Further, the detecting device in step 305 includes a filter wheel, a condenser and an electrothermal detector with an electronic control unit; the filter wheel is arranged at the light ray outlet; the condenser is arranged behind the filter wheel and is used for condensing the infrared light beams passing through the filter wheel; the infrared light beams respectively pass through a measuring filter and a reference filter on the filter wheel and then enter the electrothermal electric detector through a condenser.
Furthermore, four groups of optical filters are arranged on the optical filter wheel, and each group of optical filters comprises a reference optical filter and a measurement optical filter; the reference optical filter and the measuring optical filter are arranged on the filter wheel in an alternate mode at intervals; the center wavelength of the passband of the reference optical filter does not accord with the characteristic wavelength of the gas to be detected; and the central wavelength of the pass band of the measuring filter plate is respectively equal to the characteristic wavelength of the gas to be measured.
Further, the detecting device in step 305 includes a filter wheel of the gas chamber; a measurement air chamber and a reference air chamber are arranged on the air chamber filtering wheel; the measuring air chamber is filled with clean air or N2(ii) a The reference air chamber is filled with gas to be detected with the concentration of 99.999 percent; the measurement air chamber and the reference air chamber are arranged on the air chamber filter wheel in an interval crossing manner; wherein, a measuring filter is arranged at the inlet of the measuring air chamber; a reference filter is arranged at the inlet of the reference air chamber; the optical filtering performance of the measurement filter and the optical filtering performance of the reference filter are the same, and a gas filter disc is arranged on the light emergent side of the reference filter.
Further, the process that the high temperature infrared flue gas analyzer carries out the sample gas collection that awaits measuring still includes:
the method comprises the following steps that firstly, an air pump is started to collect measured air, and the air flow in the collection process is monitored through a flowmeter, so that the collected air flow reaches a first standard air flow;
secondly, carrying out flow reduction adjustment on the gas flow according to the first air flow change speed until the collected gas flow of the measured gas reaches a second standard gas flow;
thirdly, carrying out upward flow regulation on the gas flow according to the second air flow change speed until the gas flow reaches a third standard gas flow;
fourthly, keeping the collection flow of the measurement gas at the third standard gas flow value until a stable time period elapses, and then measuring the gas concentration; wherein the stable time period is determined by equation (1):
wherein T represents a stabilization period, TsWhen the high-temperature infrared flue gas analyzer is usedAdjusting the time length for the air flow to rise to the standard air flow value after the ignition is turned on; t isjThe time length for adjusting the air flow rate until the ignition of the high-temperature infrared flue gas analyzer is turned on is shown; t iss1Indicating a first up-flow adjustment period; t iss2Representing a second up-flow adjustment period; t isj1Indicating a first down-regulation period; λ represents a time adjustment coefficient; the expression of the time adjustment coefficient is as follows:
wherein C represents a constant coefficient, and the value range of C is 2.1-2.4.
Further, in step 102, the first airflow rate variation speed is: in the first flow reduction adjustment time period after the start of the flow reduction adjustment, the flow reduction adjustment is carried out according to the air flow variation range of 15 ml-30 ml per minute; after the first flow reduction adjustment time period after the flow reduction adjustment is started, the flow reduction adjustment is kept according to the air flow variation range of 20 ml-40 ml per minute until the air flow reaches the second standard air flow.
Further, the first down flow adjustment time period is 3.5 min.
Further, the second airflow rate of change in step 103 is: in the first rising flow adjusting time period after the rising flow adjustment is started, rising flow adjustment is carried out according to the air flow variation range of 20 ml-40 ml per minute; and in a second flow-rising adjusting time period after the flow-rising adjustment is started, the flow-rising adjustment is carried out according to the air flow variation range of 10 ml-20 ml per minute, and after the second flow-rising adjusting time period, the flow-rising adjustment is kept according to the air flow variation range of 30 ml-50 ml per minute until the air flow rises to the standard air flow value.
Further, the first upflow adjustment time period is 2 min; the second up-flow adjustment period was 3 min.
The invention has the beneficial effects that:
the high-temperature infrared flue gas analysis method provided by the invention solves the problems of sample loss and data cross interference in the analysis process of a common cold state infrared analyzer, effectively improves the detection precision and sensitivity in the gas analysis process, adopts high-temperature gold plating for the measurement pool, enables the measurement pool to measure complex and corrosive gas, can accurately and directly measure the content of H2O, comprises other pollutant monitoring factors covered by an H2O spectrum waveband, and can reduce the problem of secondary reaction of pollutants under the condition that the pollutants contain moisture at low temperature by the analysis method of a high-temperature infrared technology, thereby avoiding the problem of reduction of gas detection precision caused by the fact that secondary reaction pollutants such as ammonium nitrate salt crystals and ammonium sulfate salt crystals can corrode the cold state analyzer or are attached to the lens of the detection pool.
Meanwhile, according to the high-temperature infrared flue gas analysis method, the matching degree of the temperature and the sampling air flow is effectively improved through the air flow adjusting mode and the time period setting mode, the problem that the gas detection precision and stability are reduced due to insufficient air heating caused by unstable or overhigh air flow is effectively solved, and the accuracy, the detection efficiency and the stability of the detection process of gas concentration detection are improved.
Drawings
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a schematic structural diagram I of the high-temperature infrared flue gas analyzer according to the present invention;
FIG. 3 is a schematic structural diagram of a high-temperature infrared flue gas analyzer according to the present invention;
FIG. 4 is a schematic diagram of the internal structure of the high-temperature infrared flue gas analyzer of the present invention;
FIG. 5 is a fourth schematic structural diagram of a light-emitting unit of the high-temperature infrared flue gas analyzer of the present invention;
FIG. 6 is a fifth schematic structural diagram of a measuring cell of the high temperature infrared flue gas analyzer of the present invention;
fig. 7 is a schematic structural diagram five of a detection device of a measurement cell of the high-temperature infrared flue gas analyzer.
1, a cover plate; 2, a ventilation grid (2 x); 3, a front panel with an interface; 4, cover plate lock (4 x); 5, a thermal printer; 6, carrying handle (2 x); 7, a tablet computer; 8, a measuring cell; 9, a light emitting unit; 10, a first pressure sensor; 11, a second pressure sensor; 12, an oxygen sensor; 13, a detection device; 14, terminal block 15, fan; 16, a thermal printer; 17, a zero-air pump; 18, a measuring gas pump; 19, an infrared light source; 20, a focusing mirror; 21, connecting the emitter and the light cutting wheel; 22, a light cutting wheel; 23, a first spherical mirror; 24, a light inlet; 25, a second spherical mirror; 26, a third spherical mirror; 27, a light outlet; 28, a pyroelectric detector; 29, a filter wheel with stepper motor; 30, an over-temperature fuse; 31, cable guide holes; 32, a condenser lens; 33, detector plate.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
The embodiment of the invention provides a high-temperature infrared flue gas analysis method, which is used for solving the problems of process loss and cross interference caused by low-temperature gas sampling in the conventional infrared analysis method.
The embodiment of the invention provides a high-temperature infrared flue gas analysis method, as shown in fig. 1, the method comprises the following steps:
step 4, after the measurement is finished, the high-temperature infrared smoke gas analyzer is turned off through the computer operation, in the turning-off process of the high-temperature infrared smoke gas analyzer, the high-temperature infrared smoke gas analyzer continuously extracts ambient air to purge the high-temperature infrared smoke gas analyzer until the display of the high-temperature infrared smoke gas analyzer displays that the countdown is stopped, and then the power is cut off to detach and store the high-temperature infrared smoke gas analyzer;
and 5, data processing and analysis, wherein measured value data stored during measurement is exported through a computer, the on-site smoke emission condition is analyzed, and the on-site combustion or chemical reaction condition is analyzed through the smoke emission condition, so that the process is adjusted, and the purposes of energy conservation, emission reduction and process optimization are achieved.
The working principle of the technical scheme is as follows: the high-temperature infrared flue gas analysis method provided by the embodiment is based on the lambert beer law, combines the high-precision hardware filtering single-beam dual-wavelength technology (IFC technology) and the gas-related filtering technology (GFC technology) to remove the cross interference between infrared bands, and simultaneously performs the cross interference compensation of matrix type big data, thereby realizing the CO, NO and N cross interference compensation2O、NO2、NH3、CH4、HCl、SO2、CO2、H2O、O2High precision measurement. In the construction process of the high-temperature original state analysis method, high-temperature sampling, high-temperature filtering and high-temperature infrared detection and analysis are carried out at the temperature of more than 185 ℃ in the whole process, and the samples are directly analyzed without pretreatment such as gas drying, dilution, cooling and the like, so that the maximum limit is realizedThe process loss is reduced, and the measurement result is more real and reliable. Meanwhile, two noble metals of Au and Ba are adopted to manufacture the optical lens, the infrared absorption range of the analyzer is provided, the detection limit of the analyzer is improved, and the sensitivity and the precision of the analyzer are enhanced. In the data processing process, a real measured substance curve is fitted by using Lambert beer law infrared absorption and full-component cross interference compensation matrix fitting partial least square method, and a data result is guaranteed in a curve obtaining mode. Specifically, in the gas detection process, since the cross interference among the gas components does not have a linear data relationship, the calculation and compensation cannot be performed through simple linear data, if the analyzer wants to realize accurate measurement, a data cross interference test under each gradient concentration of the multi-point matrix type components must be performed, and then an accurate result of the real concentration is obtained through the cross interference compensation of the matrix type big data. The structure of the high-temperature infrared flue gas analyzer is shown in figures 2-7.
The effect of the above technical scheme is as follows: the high-temperature infrared flue gas analysis method is superior to the whole-process high-temperature design, H2O is in the gasification stage, so the analyzer can accurately and directly measure H2O content including H2The O spectral band covers other contaminant monitoring factors and the analyzer of the high temperature infrared technology additionally enables the device to reduce the problem of secondary reactions of contaminants under low temperature moisture conditions, secondary reaction contaminants such as ammonium nitrate salt crystals and ammonium sulfate salt crystals that can corrode the analyzer in the cold state or adhere to the lenses of the detection cell. The gold-plated optical measurement cell is adopted for high-temperature infrared analysis, and the measurement optical path is increased, so that the detection precision and sensitivity of the analyzer are ensured, and the high-temperature gold-plated measurement gas chamber enables the analyzer to measure complex and corrosive gas. Meanwhile, the method solves the problem of the application of cross interference compensation of matrix type big data on the basis of the Lambert beer law, the IFC technology, the GFC technology, the high-temperature original state analysis and the filter wheel hardware technology, and solves the problems of CO, NO and N2O、NO2、NH3、CH4、HCl、SO2、CO2、H2O、O2Ultra-precision of equal smoke componentsThe cross interference problem in the measurement greatly improves the measurement precision and accuracy, and the ultra-precise measurement can be realized.
In an embodiment of the present invention, the step 3 of allowing the sample gas to be measured to enter the high temperature measurement cell of the high temperature infrared flue gas analyzer through the optical path system of the high temperature infrared flue gas analyzer by using a high temperature sampling device connected to the high temperature infrared flue gas analyzer and a high temperature sampling device integrated inside the high temperature infrared flue gas analyzer includes:
301, enabling the infrared light beam to enter a measuring cell through a light ray inlet of the measuring cell;
step 302, the infrared light beams are respectively and directly irradiated onto the side wall of a first spherical mirror, and the first spherical mirror is arranged in parallel to the bottom surface of the measuring cell;
step 303, reflecting the infrared light beams to a second spherical mirror through the first spherical mirror, and reflecting the infrared light beams to a curved mirror surface on the first spherical mirror through the second spherical mirror; the second spherical mirror is arranged at the bottom of the measuring cell and close to a light ray inlet;
step 304, reflecting the infrared light beam to a third spherical mirror through a curved mirror surface on the first spherical mirror; after the infrared light beam reaches the specified infrared absorption optical path through continuous reflection, the infrared light beam is reflected by a third spherical mirror to be emitted from a light ray outlet of the measuring cell; the third spherical mirror is arranged at the bottom of the measuring cell and close to the light ray outlet.
The working principle of the technical scheme is adopted; the infrared light beam enters from the light inlet, then directly irradiates on the first spherical surface, and then is reflected on the second spherical surface mirror and the third spherical surface mirror. The longest optical path of 12 meters can be realized by multiple reflections of three spherical mirrors. The infrared light enters the detection device directly from the measuring cell. Passing through a filter wheel, a condenser and a thermoelectric detector with an electronic control unit. The infrared light passes through the measurement filter and the reference filter on the filter wheel and then enters the detector through the condenser.
The effect of the above technical scheme is as follows: the infrared absorption is wide, the detection limit of the instrument is improved, and the sensitivity and the precision of gas concentration detection are enhanced.
According to one embodiment of the invention, the structure of the detection device is different according to the detected gas:
when the measured gas is SO2、CO2、NO2And H2When O is needed, a gas detection mode adopts a double-frequency measurement method, and at the moment, the detection device comprises a filter wheel, a condenser and an electrothermal detector with an electronic control unit; the filter wheel is arranged at the light ray outlet; the condenser is arranged behind the filter wheel and is used for condensing the infrared light beams passing through the filter wheel; the infrared light beams respectively pass through a measuring filter and a reference filter on the filter wheel and then enter the electrothermal electric detector through a condenser. Four groups of optical filters are arranged on the filter wheel, and each optical filter comprises a reference optical filter and a measurement optical filter; the reference optical filter and the measuring optical filter are arranged on the filter wheel in an alternate mode at intervals; the center wavelength of the passband of the reference optical filter does not accord with the characteristic wavelength of the gas to be detected; and the central wavelength of the pass band of the measuring filter plate is respectively equal to the characteristic wavelength of the gas to be measured.
When the measured gas is CO, NO, HCl、NH3The gas detection mode adopts a gas filtration correlation method, and the detection device comprises a gas chamber filter wheel; a measurement air chamber and a reference air chamber are arranged on the air chamber filtering wheel; the measuring air chamber is filled with clean air or N2(ii) a The reference air chamber is filled with gas to be detected with the concentration of 99.999 percent; the measurement air chamber and the reference air chamber are arranged on the air chamber filter wheel in an interval crossing manner; wherein, a measuring filter is arranged at the inlet of the measuring air chamber; a reference filter is arranged at the inlet of the reference air chamber; the optical filtering performance of the measurement filter and the optical filtering performance of the reference filter are the same, and a gas filter disc is arranged on the light emergent side of the reference filter.
In addition, when the high-temperature infrared flue gas analysis method provided by the embodiment is used for measuring the oxygen concentration, a zirconium oxide sensor method is adopted, and when the zirconium oxide sensor is used for measuring, the instrument hardware structure of the gas measurement section is adjusted according to the oxygen detection principle in practical application. The principle of the oxygen measuring method is as follows: the measurement of oxygen was performed by means of an oxyge cell. The measurement gas and the reference gas (ambient air) are separated by a misfit. Because of the difference in oxygen partial pressure on both sides, oxygen ions move through the membrane phase. This creates a potential difference. The oxygen sensor comprises a measuring cell and a pump chamber to maintain a constant oxygen concentration. The oxygen concentration can be converted from the energy consumed thereby. The precise oxygen concentration in the measured gas can be calculated by a known ratio of the energy consumption to the oxygen concentration signal.
The effect of the above technical scheme is as follows: solves the problems of CO, NO and N2O、NO2、NH3、CH4、HCl、SO2、CO2、H2O、O2The cross interference problem in the ultra-precise measurement of the smoke components is solved, and the accuracy and precision of the smoke component measurement are greatly improved.
In an embodiment of the present invention, the step 1 of measuring the gas includes:
step 101, starting an air pump to collect measured air, and monitoring the air flow in the collection process through a flowmeter to enable the collected air flow to reach a first standard air flow; the first standard gas flow rate is as follows: 725 ml/min;
102, performing flow reduction adjustment on the gas flow according to the first air flow change speed until the collected gas flow of the measurement gas reaches a second standard gas flow; the second standard gas flow rate is as follows: 480 ml/min;
103, performing ascending adjustment on the gas flow according to the second air flow change speed until the gas flow reaches a third standard gas flow; the third standard gas flow rate is as follows: 750 ml/min;
step 104, keeping the collection flow of the measurement gas at the third standard gas flow value until a stable time period elapses, and then measuring the gas concentration; wherein the stable time period is determined by equation (1):
wherein T represents a stabilization period, TsThe time length for adjusting the air flow to rise to the standard air flow value after the high-temperature infrared flue gas analyzer is ignited and turned on is shown; t isjThe time length for adjusting the air flow rate until the ignition of the high-temperature infrared flue gas analyzer is turned on is shown; t iss1Indicating a first up-flow adjustment period; t iss2Representing a second up-flow adjustment period; t isj1Indicating a first down-regulation period; λ represents a time adjustment coefficient; the expression of the time adjustment coefficient is as follows:
wherein C represents a constant coefficient, and the value range of C is 2.1-2.4.
The working principle of the technical scheme is as follows: through the standard gas flow who sets up three stages to and the regulation mode of falling stream and rising, can be through controlling the air flow in the sampling process of measurand gas, make the measurand gas heating more abundant, and can reach heating standard temperature more fast. Meanwhile, the specific duration of the stable time period is determined by the indexes of the first up-flow adjustment time period, the second up-flow adjustment time period and the first down-flow adjustment time period.
The effect of the above technical scheme is as follows: the measured gas is heated more sufficiently by controlling the air flow in the sampling process of the measured gas, and the temperature of the measured gas can reach the heating standard temperature more quickly. Meanwhile, the specific duration of the stable time period is set through the time index adopted in the air flow regulation process, so that the matching between the stable time period and the actual air flow regulation condition can be effectively improved. The time length of the stable time period can guarantee that the air flow is stabilized in the effective observation time of the standard air flow, and the problem that the detection precision of the gas concentration is reduced due to the fact that the air flow is unstable and changes subsequently caused by the short time period is avoided. Meanwhile, the reduction of gas detection efficiency caused by overlong stable time period can be avoided, and unnecessary gas detection time is prolonged.
In one embodiment of the present invention, the first airflow rate variation speed in step 102 is: in the first flow reduction adjustment time period after the start of the flow reduction adjustment, the flow reduction adjustment is carried out according to the air flow variation range of 15 ml-30 ml per minute; after the first flow reduction adjustment time period after the flow reduction adjustment is started, the flow reduction adjustment is kept according to the air flow variation range of 20 ml-40 ml per minute until the air flow reaches the second standard air flow.
Wherein the first down flow adjustment time period is 3.5 min.
The second airflow rate of change in step 103 is: in the first rising flow adjusting time period after the rising flow adjustment is started, rising flow adjustment is carried out according to the air flow variation range of 20 ml-40 ml per minute; and in a second flow-rising adjusting time period after the flow-rising adjustment is started, the flow-rising adjustment is carried out according to the air flow variation range of 10 ml-20 ml per minute, and after the second flow-rising adjusting time period, the flow-rising adjustment is kept according to the air flow variation range of 30 ml-50 ml per minute until the air flow rises to the standard air flow value.
Wherein the first upflow adjustment time period is 2 min; the second up-flow adjustment period was 3 min.
The working principle of the technical scheme is as follows: by setting a specific time period and a specific air flow adjustment variation, stable adjustment of air flow reduction and increase is achieved.
The effect of the above technical scheme is as follows: through the adjusting mode and the time quantum setting mode of air flow, the matching degree of temperature and sampling air flow is effectively improved, the problems of gas detection precision and stability reduction caused by insufficient air heating due to unstable or overhigh air flow are effectively avoided, and the accuracy, the detection efficiency and the stability of the detection process of gas concentration detection are further improved.
Meanwhile, the airflow is subjected to the airflow reducing adjustment according to the set specific first airflow reducing adjustment time period and the corresponding airflow variable quantity range, so that the stability of the stable adjustment of the airflow can be improved, the adjustment time of the airflow required when the airflow reaches the standard airflow is shortened, and the adjustment speed of the airflow is improved. The problem that the subsequent gas concentration detection accuracy is reduced due to insufficient gas heating caused by too high or too low air flow adjusting speed is solved.
It will be apparent to those skilled in the art that various changes and modifications may be made in 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 of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A high-temperature infrared flue gas analysis method is characterized by comprising the following steps:
step 1, sequentially connecting a calibrated high-temperature infrared flue gas analyzer, high-temperature sampling equipment and a computer and connecting a power supply; starting a high-temperature infrared flue gas analyzer, a high-temperature sampling device and a computer;
step 2, the high-temperature infrared flue gas analyzer and the sampling device enter a preheating standby stage, the preheating time is 45-60 minutes, and meanwhile, the instrument is continuously swept through ambient air in the preheating standby stage; heating the high-temperature infrared flue gas analyzer and the high-temperature sampling device to 185 ℃;
step 3, enabling sample gas to be detected to enter a high-temperature measuring pool of the high-temperature infrared flue gas analyzer through a whole-course high-temperature sampling device connected with the high-temperature infrared flue gas analyzer and a high-temperature sampling device integrated in the high-temperature infrared flue gas analyzer, controlling the high-temperature infrared flue gas analyzer to measure gas concentration and monitor a measured value of the gas concentration in real time through a light path system of the high-temperature infrared flue gas analyzer and corresponding calculation, and storing the measured value through a computer;
step 4, after the measurement is finished, the high-temperature infrared smoke gas analyzer is turned off through the computer operation, in the turning-off process of the high-temperature infrared smoke gas analyzer, the high-temperature infrared smoke gas analyzer continuously extracts ambient air to purge the high-temperature infrared smoke gas analyzer until the display of the high-temperature infrared smoke gas analyzer displays that the countdown is stopped, and then the power is cut off to detach and store the high-temperature infrared smoke gas analyzer;
and 5, data processing and analysis, namely exporting measured value data stored during measurement through a computer, analyzing the on-site smoke emission condition, and analyzing the on-site combustion or chemical reaction condition through the smoke emission condition.
2. The analysis method according to claim 1, wherein the step 3 of passing the sample gas to be measured through a high temperature sampling device connected to the high temperature infrared flue gas analyzer and a sampling device integrated inside the high temperature infrared flue gas analyzer into a high temperature measurement cell of the high temperature infrared flue gas analyzer, and then performing correlation calculation through an optical system comprises:
301, enabling the infrared light beam to enter a measuring cell through a light ray inlet of the measuring cell;
step 302, the infrared light beams are respectively and directly irradiated onto the side wall of a first spherical mirror, and the first spherical mirror is arranged in parallel to the bottom surface of the measuring cell;
step 303, reflecting the infrared light beams to a second spherical mirror through the first spherical mirror, and reflecting the infrared light beams to a curved mirror surface on the first spherical mirror through the second spherical mirror; the second spherical mirror is arranged at the bottom of the measuring cell and close to a light ray inlet;
step 304, reflecting the infrared light beam to a third spherical mirror through a curved mirror surface on the first spherical mirror; after reaching the specified optical path, the infrared light beam is reflected by a third spherical mirror to be emitted from a light ray outlet of the measuring cell; the third spherical mirror is arranged at the bottom of the measuring cell and close to a light ray outlet;
and 305, directly enabling the infrared light beam emitted from the light ray outlet to enter a detection device, and obtaining a measurement data value of the concentration of the measurement gas in real time through the detection device.
3. The method of claim 2, wherein the detecting means of step 305 comprises a filter wheel, a condenser, and a pyroelectric detector with an electronic control unit; the filter wheel is arranged at the light ray outlet; the condenser is arranged behind the filter wheel and is used for condensing the infrared light beams passing through the filter wheel; the infrared light beams respectively pass through a measuring filter and a reference filter on the filter wheel and then enter the electrothermal electric detector through a condenser.
4. The analysis method according to claim 3, wherein four sets of filters are disposed on the filter wheel, and each set of filters comprises a reference filter and a measurement filter; the reference optical filter and the measuring optical filter are arranged on the filter wheel in an alternate mode at intervals; the center wavelength of the passband of the reference optical filter does not accord with the characteristic wavelength of the gas to be detected; and the central wavelength of the pass band of the measuring filter plate is respectively equal to the characteristic wavelength of the gas to be measured.
5. The method of claim 2, wherein the detecting device of step 305 comprises a gas cell filter wheel; a measurement air chamber and a reference air chamber are arranged on the air chamber filtering wheel; the measuring air chamber is filled with clean air or N2(ii) a The reference air chamber is filled with gas to be detected with the concentration of 99.999 percent; the measurement air chamber and the reference air chamber are arranged on the air chamber filter wheel in an interval crossing manner; wherein, a measuring filter is arranged at the inlet of the measuring air chamber; a reference filter is arranged at the inlet of the reference air chamber; the optical filtering performance of the measurement filter and the optical filtering performance of the reference filter are the same, and a gas filter disc is arranged on the light emergent side of the reference filter.
6. The analysis method according to claim 1, wherein the high temperature infrared flue gas analyzer performs a process of collecting the sample gas to be measured, and further comprises:
the method comprises the following steps that firstly, a sampling pump is started to collect measured gas, and the gas flow in the collecting process is monitored through a flowmeter, so that the collected gas flow reaches a first standard gas flow;
secondly, carrying out flow reduction adjustment on the gas flow according to the first air flow change speed until the collected gas flow of the measured gas reaches a second standard gas flow;
thirdly, carrying out upward flow regulation on the gas flow according to the second air flow change speed until the gas flow reaches a third standard gas flow;
fourthly, keeping the collection flow of the measurement gas at the third standard gas flow value until a stable time period elapses, and then measuring the gas concentration; wherein the stable time period is determined by equation (1):
wherein T represents a stabilization period, TsThe time length for adjusting the air flow to rise to the standard air flow value after the high-temperature infrared flue gas analyzer is ignited and turned on is shown; t isjThe time length for adjusting the air flow rate until the ignition of the high-temperature infrared flue gas analyzer is turned on is shown; t iss1Indicating a first up-flow adjustment period; t iss2Representing a second up-flow adjustment period; t isj1Indicating a first down-regulation period; λ represents a time adjustment coefficient; the expression of the time adjustment coefficient is as follows:
wherein C represents a constant coefficient, and the value range of C is 2.1-2.4.
7. The method of claim 6, wherein the first rate of change of air flow rate of step 102 is: in the first flow reduction adjustment time period after the start of the flow reduction adjustment, the flow reduction adjustment is carried out according to the air flow variation range of 15 ml-30 ml per minute; after the first flow reduction adjustment time period after the flow reduction adjustment is started, the flow reduction adjustment is kept according to the air flow variation range of 20 ml-40 ml per minute until the air flow reaches the second standard air flow.
8. The analysis method according to claim 7, wherein the first down-flow adjustment time period is 3.5 min.
9. The method of claim 6, wherein the second rate of change of air flow rate of step 103 is: in the first rising flow adjusting time period after the rising flow adjustment is started, rising flow adjustment is carried out according to the air flow variation range of 20 ml-40 ml per minute; and in a second flow-rising adjusting time period after the flow-rising adjustment is started, the flow-rising adjustment is carried out according to the air flow variation range of 10 ml-20 ml per minute, and after the second flow-rising adjusting time period, the flow-rising adjustment is kept according to the air flow variation range of 30 ml-50 ml per minute until the air flow rises to the standard air flow value.
10. The analytical method of claim 9, wherein the first upflow adjustment period is 2 min; the second up-flow adjustment period was 3 min.
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