CO concentration measurement optimization system and method
By transforming the sampling components and adopting hot standby redundant configuration and automatic switching of sampling gas lines and vacuuming technology, the problem of intermittent CO concentration measurement data in the tail flue and affected measurement accuracy has been solved, and continuous and stable CO concentration has been achieved. measurement, improving measurement accuracy and stability.
Patent Information
- Application Number
- CN202411279159.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2025-01-24
AI Technical Summary
The CO concentration measurement data of the tail flue duct cannot be continuously sampled during the purge process, resulting in interruption of measurement data. The residual gas after purge affects the measurement accuracy and stability, seriously affecting the effect and accuracy of boiler combustion optimization.
By modifying the sampling components and adopting hot standby redundant configuration, combined with automatic switching of the sampling gas path and vacuuming technology, continuous and stable CO concentration measurement is achieved. Specific measures include: dividing the sampling gas path into the first and second sampling gas paths, alternately sampling and back-purging, and using a vacuum pump to evacuate the gas path to remove residual gas.
It realizes the continuous operation of the sampling equipment and the continuity of the measurement data, effectively solves the impact of residual gas on the measurement accuracy, and improves the measurement accuracy and stability of the overall system.
Smart Images
Figure CN119355283A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of CO concentration measurement, and in particular to a CO concentration measurement optimization system and method. Background Art
[0002] The measurement data of CO concentration in the tail flue plays a vital role in the optimization of boiler combustion in coal-fired power generation units. It is the basic data for optimizing the total amount of boiler secondary air. However, the working environment of the tail flue is a typical gas-solid two-phase flow, which requires the measurement device to obtain sample gas for analysis through sampling. In order to prevent the sampling system from being blocked during long-term operation, an automatic purge maintenance system is usually equipped to regularly clean the sampling gas path.
[0003] However, in actual applications, the gas circuit of the sampling equipment cannot be sampled continuously during the purge process, which leads to a large number of interruptions in the measurement data. This data discontinuity is not conducive to the boiler combustion process that requires continuous monitoring and optimization. In addition, a certain amount of gas usually remains in the gas circuit after purging, and these residual gases will have a significant impact on the measurement accuracy and stability of subsequent sampling. Since the measurement of CO concentration is at the PPm level, even if there is a very small amount of gas remaining in the gas circuit, it may cause the measurement accuracy to deviate significantly from the normal value, thereby seriously affecting the effect and accuracy of boiler combustion optimization. Summary of the invention
[0004] In view of the defects in the prior art, the present invention provides a CO concentration measurement optimization system and method, which realizes continuous and stable CO concentration measurement by modifying the sampling components, adopting hot standby redundant configuration, and combining automatic switching of the sampling gas path and vacuum extraction technology.
[0005] On the one hand, an embodiment of the present invention provides a CO concentration measurement optimization system, which includes a sample gas inlet, a flow meter, a sampling gas circuit and a back-purge device, wherein the sample gas inlet, the flow meter, and the sampling gas circuit are connected in sequence, and the back-purge device is connected to the sampling gas circuit; the sampling gas circuit includes a first sampling gas circuit and a second sampling gas circuit, and the flow meter is connected to the first sampling gas circuit and the second sampling gas circuit respectively; the first sampling gas circuit and the second sampling gas circuit can alternately perform sampling and back-purge.
[0006] Preferably, the first gas collection circuit includes a first air cooling unit and a first sampler connected in sequence, the second gas collection circuit includes a second air cooling unit and a second sampler connected in sequence, and the flow meter is respectively connected to the first air cooling unit and the second air cooling unit through a four-way valve.
[0007] Preferably, the back-purge device is connected to the four-way valve via a three-way valve.
[0008] Preferably, the back-purge device further comprises a vacuum tank and a vacuum pump, and the three-way valve, the vacuum tank and the vacuum pump are connected in sequence.
[0009] On the other hand, an embodiment of the present invention provides a CO concentration measurement optimization method, including:
[0010] Step 1, the flue tail gas enters the first sampling gas path through the sample gas inlet and the flow meter, and CO sampling is performed through the first sampling gas path; and the CO measurement data is transmitted to the terminal device;
[0011] Step 2, determine whether the sampling time exceeds the set value;
[0012] Step 3, when the sampling time exceeds the set value, the sampling gas path is switched so that the flue exhaust gas enters the second sampling gas path through the sample gas inlet and the flow meter, CO sampling is performed through the second sampling gas path, and back-purging is performed through the back-purging device.
[0013] Preferably, in step 1, CO sampling is performed through the first sampling gas path, including: air cooling the flue exhaust gas through the first air cooling unit, and sampling the air-cooled flue exhaust gas through the first sampler; in step 2, CO sampling is performed through the second sampling gas path, including: air cooling the flue exhaust gas through the second air cooling unit, and sampling the air-cooled flue exhaust gas through the second sampler.
[0014] Preferably, when the sampling time exceeds the set value, the sampling gas path is switched so that the flue tail gas enters the second sampling gas path through the sample gas inlet and the flow meter, CO sampling is performed through the second sampling gas path, and back-purge is performed through the back-purge device, including:
[0015] Open the three-way solenoid valve, and switch the four-way solenoid valve from PA connection to AT connection and PB connection. The flue exhaust gas enters the second sampling gas path through the sample gas inlet and the flowmeter and the four-way valve for CO sampling. The compressed air is back-purged through the three-way solenoid valve and the four-way solenoid valve.
[0016] Preferably, after the back-purge is completed, a vacuum pump is started to evacuate the first sampling gas path.
[0017] The beneficial effects of the present invention are as follows: A CO concentration measurement optimization system and method provided by the embodiment of the present invention realizes the continuous operation of the sampling equipment and the continuity of the measurement data by adopting a hot standby redundantly configured sampler and gas path components. By adding a gas path vacuum pump to the automatic purge system and performing a vacuum operation on the hot standby sampling gas path before switching, the influence of residual gas on the measurement accuracy is effectively solved, and the measurement accuracy and stability of the overall system are improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.
[0019] Figure 1 A structural schematic diagram of a CO concentration measurement optimization system is provided for an embodiment of the present invention;
[0020] Figure 2 A flow chart of a CO concentration measurement optimization method provided in an embodiment of the present invention.
[0021] In the accompanying drawings, 1-flow meter, 2-four-way valve, 31-first air cooling unit, 32-second air cooling unit, 41-first sampler, 42-second sampler, 5-three-way valve, 6-vacuum pump. DETAILED DESCRIPTION
[0022] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.
[0023] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.
[0024] like Figure 1 As shown, an embodiment of the present invention provides a CO concentration measurement optimization system, which includes a sample gas inlet, a flow meter, a sampling gas circuit and a back-purge device, wherein the sample gas inlet, the flow meter, and the sampling gas circuit are connected in sequence, and the back-purge device is connected to the sampling gas circuit; the sampling gas circuit includes a first sampling gas circuit and a second sampling gas circuit, and the flow meter is connected to the first sampling gas circuit and the second sampling gas circuit respectively; the first sampling gas circuit and the second sampling gas circuit can alternately perform sampling and back-purge.
[0025] Specifically, the sample gas inlet is used to receive the sample gas in the tail flue, the flow meter is used to measure the flow of the sample gas, the sampling gas path is used to sample the sample gas, and the back-purge device is used to back-purge the sampling gas path.
[0026] In an embodiment of the present invention, the first gas collection circuit includes a first air cooling unit and a first sampler connected in sequence, the second gas collection circuit includes a second air cooling unit and a second sampler connected in sequence, and the flow meter is respectively connected to the first air cooling unit and the second air cooling unit through a four-way valve.
[0027] Specifically, the sampling gas circuit is divided into a first sampling gas circuit and a second sampling gas circuit, and the two can perform sampling and back-purging alternately. The flow meter is connected to the first sampling gas circuit and the second sampling gas circuit through a four-way valve to achieve flow measurement and switching of the sampling gas circuit. The air cooling unit is used to cool the sample gas to reduce the temperature burden of the sampler and improve the sampling accuracy. The sampler is used to sample the cooled sample gas and transmit the sampling data to the terminal device.
[0028] In an embodiment of the present invention, the back-purge device is connected to the four-way valve via a three-way valve, and the back-purge device further comprises a vacuum tank and a vacuum pump, and the three-way valve, vacuum tank and vacuum pump are connected in sequence.
[0029] Specifically, the back-purge device is connected to the four-way valve through a three-way valve to realize the back-purge and vacuum operation of the sampling gas path. The back-purge device also includes a vacuum tank and a vacuum pump, the vacuum tank is used to store compressed air for back-purge, and the vacuum pump is used to vacuum the sampling gas path.
[0030] It should be noted that the calculation of the back-purge time is mainly based on the time required to completely purge out the residual gas in the sampling gas path. This usually depends on the volume of the sampling gas path, the flow rate of the back-purge gas, and the required purge effect. Specifically, it includes: Estimating the volume of the sampling gas path: According to the length and diameter of the sampling gas path, its volume V can be estimated. Determining the back-purge gas flow rate: The flow rate Q of the back-purge gas is usually determined by the back-purge device (such as a compressed air tank and a pressure reducing valve), and can be measured by a flow meter or obtained by referring to the equipment specification. Calculating the theoretical purge time: In theory, the time required to purge all the gas in the sampling gas path can be approximated as the gas path volume V divided by the back-purge gas flow rate. However, in actual applications, due to the uneven mixing and distribution of gases, the actual purge time may need to be longer. Considering the safety margin: In order to ensure the purge effect, a certain safety margin is usually added to the theoretical purge time to obtain the final purge time.
[0031] Specifically, the formula for calculating the back-purge time is: t purge =k purge · V / Q , where V is the volume of the back-purge channel, Q is the flow rate of the back-purge gas, and k purge is an empirical coefficient used to consider the non-uniformity and safety margin in the actual purge process, and this coefficient is greater than 1. Of course, in other embodiments, it is also necessary to consider the effect of dead volume on the purge efficiency, as well as the effect of initial pressure and gas temperature on the purge process.
[0032] Furthermore, the calculation formula for the back-purge time provided in the embodiment of the present invention is:
[0033] tpurge =k purge · V / Q ·(1+ DL )·( P0 / Patm )·(1+ Tr oom / Tgas), where L is the length of the gas path, D is the diameter of the sampling gas path, P0 is the initial pressure in the sampling gas path, Patm is the atmospheric pressure, and Troom is the room temperature.
[0034] The specific working process is as follows: the flue tail gas enters the system through the sample gas inlet, firstly its flow is measured by the flow meter, and then enters the first sampling gas path for CO sampling. During the sampling process, the first air cooling unit cools the sample gas, the first sampler samples the cooled sample gas, and transmits the sampling data to the terminal device.
[0035] The system determines whether the sampling time exceeds the set value. When the sampling time reaches the set value, the system switches the sampling gas path so that the flue gas enters the second sampling gas path for CO sampling. At the same time, the back-purge device back-purges and vacuums the first sampling gas path to remove residual gas and improve the accuracy of subsequent sampling.
[0036] During the sampling process of the second sampling gas path, the first sampling gas path is back-purged and vacuumed. The back-purging operation is achieved by switching the three-way valve and the four-way valve. Compressed air flows out of the vacuum tank to back-purge the first sampling gas path. The back-purging time is calculated based on the length, diameter and residual gas volume of the sampling gas path to ensure that the residual gas is completely removed. After the back-purging is completed, the vacuum pump is started to vacuum the first sampling gas path. The vacuuming time is also calculated based on the characteristics of the sampling gas path to ensure that the gas in the gas path is completely extracted.
[0037] When the sampling time of the second sampling gas path reaches the set value, the system switches the sampling gas path again, so that the flue gas re-enters the first sampling gas path for CO sampling. At the same time, the back-purge device back-purges and vacuums the second sampling gas path.
[0038] This cycle is repeated, and by alternating sampling and back-purge operations, continuous and stable measurement of CO concentration in the tail flue is achieved.
[0039] In summary, the CO concentration measurement optimization system of the present invention realizes the continuous operation of the sampling equipment and the continuity of the measurement data by adopting the hot standby redundant configuration of the sampler and gas path components. By adding a gas path vacuum pump to the automatic purge system and performing a vacuum operation on the hot standby sampling gas path before switching, the influence of residual gas on the measurement accuracy is effectively solved, and the measurement accuracy and stability of the overall system are improved.
[0040] Example 2
[0041] like Figure 2 As shown, an embodiment of the present invention provides a CO concentration measurement optimization method, including:
[0042] Step 1, the flue tail gas enters the first sampling gas path through the sample gas inlet and the flow meter, and CO sampling is performed through the first sampling gas path; and the CO measurement data is transmitted to the terminal device;
[0043] Step 2, determine whether the sampling time exceeds the set value;
[0044] Step 3, when the sampling time exceeds the set value, the sampling gas path is switched so that the flue exhaust gas enters the second sampling gas path through the sample gas inlet and the flow meter, CO sampling is performed through the second sampling gas path, and back-purging is performed through the back-purging device.
[0045] In an embodiment of the present invention, in step 1, CO sampling is performed through the first sampling gas path, including: air cooling the flue exhaust gas through the first air cooling unit, and sampling the air-cooled flue exhaust gas through the first sampler; in step 2, CO sampling is performed through the second sampling gas path, including: air cooling the flue exhaust gas through the second air cooling unit, and sampling the air-cooled flue exhaust gas through the second sampler.
[0046] In an embodiment of the present invention, when the sampling time exceeds the set value, the sampling gas path is switched so that the flue tail gas enters the second sampling gas path through the sample gas inlet and the flow meter, CO sampling is performed through the second sampling gas path, and back-purging is performed through the back-purging device, including:
[0047] Open the three-way solenoid valve, and switch the four-way solenoid valve from PA connection to AT connection and PB connection. The flue exhaust gas enters the second sampling gas path through the sample gas inlet and the flowmeter and the four-way valve for CO sampling. The compressed air is back-purged through the three-way solenoid valve and the four-way solenoid valve.
[0048] In an embodiment of the present invention, after the back-purge is completed, the vacuum pump is started to evacuate the first sampling gas path.
[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.
Claims
1. A CO concentration measurement optimization system, characterized in that: The system includes a sample gas inlet, a flowmeter, a sampling gas circuit and a back-purge device, wherein the sample gas inlet, the flowmeter and the sampling gas circuit are connected in sequence, and the back-purge device is connected to the sampling gas circuit; the sampling gas circuit includes a first sampling gas circuit and a second sampling gas circuit, and the flowmeter is connected to the first sampling gas circuit and the second sampling gas circuit respectively; the first sampling gas circuit and the second sampling gas circuit can alternately perform sampling and back-purge.
2. A CO concentration measurement optimization system according to claim 1, characterized in that: The first gas collection circuit includes a first air cooling unit and a first sampler connected in sequence, the second gas collection circuit includes a second air cooling unit and a second sampler connected in sequence, and the flow meter is respectively connected to the first air cooling unit and the second air cooling unit through a four-way valve.
3. A CO concentration measurement optimization system according to claim 1, characterized in that: The back-purge device is connected to the four-way valve via a three-way valve.
4. A CO concentration measurement optimization system according to claim 1, characterized in that: The back-purge device also includes a vacuum tank and a vacuum pump, and the three-way valve, the vacuum tank and the vacuum pump are connected in sequence.
5. A CO concentration measurement optimization method, characterized in that: include: Step 1, flue tail gas enters the first sampling gas path through the sample gas inlet and the flow meter, and CO sampling is performed through the first sampling gas path; And transmit CO measurement data to terminal equipment; Step 2, determine whether the sampling time exceeds the set value; Step 3, when the sampling time exceeds the set value, the sampling gas path is switched so that the flue exhaust gas enters the second sampling gas path through the sample gas inlet and the flow meter, CO sampling is performed through the second sampling gas path, and back-purging is performed through the back-purging device.
6. A CO concentration measurement optimization method according to claim 5, characterized in that: In step 1, CO sampling is performed through the first sampling gas path, including: air cooling the flue exhaust gas through the first air cooling unit, and sampling the air-cooled flue exhaust gas through the first sampler; in step 2, CO sampling is performed through the second sampling gas path, including: air cooling the flue exhaust gas through the second air cooling unit, and sampling the air-cooled flue exhaust gas through the second sampler.
7. A CO concentration measurement optimization method according to claim 6, characterized in that: In step 3, when the sampling time exceeds the set value, the sampling gas path is switched so that the flue tail gas enters the second sampling gas path through the sample gas inlet and the flow meter, CO sampling is performed through the second sampling gas path, and back-purging is performed through the back-purging device, including: Open the three-way solenoid valve, and switch the four-way solenoid valve from PA connection to AT connection and PB connection. The flue exhaust gas enters the second sampling gas path through the sample gas inlet and the flowmeter and the four-way valve for CO sampling. The compressed air is back-purged through the three-way solenoid valve and the four-way solenoid valve.
8. A CO concentration measurement optimization method according to claim 7, characterized in that: After the back-purge is completed, the vacuum pump is started to evacuate the first sampling gas path.