A method for detecting combustion efficiency of an elevated flare and a tethered balloon carrier system

Abstract

The present disclosure relates to a method for detecting the combustion efficiency of an elevated flare and a tethered balloon carrier system, the method comprising: determining a background concentration based on a gas concentration measured at a first target position; determining a measured concentration based on a gas concentration measured at a second target position, the second target position representing a position downwind of the flame of the elevated flare and within the range of the smoke flow, the measured concentration representing the concentration of the exhaust gas after the elevated flare is burned after being diluted with air; determining an initial concentration based on the concentration of the exhaust gas measured at the air inlet of the elevated flare, the initial concentration representing the concentration of the exhaust gas before the elevated flare is burned; in the case where the actual concentration is determined based on the initial concentration and the measured concentration, determining the ratio of the initial concentration to the actual concentration as the combustion efficiency of the elevated flare, the actual concentration representing the concentration of the exhaust gas after the elevated flare is burned before being diluted with air. The present disclosure can determine the actual exhaust gas concentration and the actual combustion efficiency after the elevated flare is burned.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, and in particular to an elevated flare combustion efficiency detection method and a tethered balloon carrier system. Background Art

[0002] Elevated flares are essential safety facilities for petrochemical enterprises. They are mainly used to handle internal leaks such as safety valves connected to petrochemical factories, overpressure emissions during production, purge gas emissions during device startup and shutdown, and emergency emissions in accident conditions. Combustion efficiency (CE) is an important indicator for measuring whether volatile organic compounds (VOCs) in elevated flares are fully burned and whether emissions meet standards. However, unlike other chimney emission methods, elevated flare combustion is not closed, and its emission port is in the flame. It is affected by combustion temperature, elevated flare gas flow rate, and steam. Traditional monitoring methods at home and abroad are difficult to achieve sampling and analysis of elevated flare emission ports. In addition, the elevated flare combustion efficiency cannot be inferred from the elevated flare inlet sampling and detection data alone. Summary of the invention

[0003] In order to solve at least one of the above-mentioned technical problems, the present disclosure proposes an elevated flare combustion efficiency detection method and a tethered balloon carrier system.

[0004] According to some embodiments of the present disclosure, a method for detecting the combustion efficiency of an elevated flare is provided, which is applied to a tethered balloon vehicle system, wherein the system is used to float up into the air and measure the concentration data of the exhaust gas after the combustion of the elevated flare; the method includes: determining the background concentration based on the gas concentration measured at a first target position, wherein the first target position represents a position downwind of the flame of the elevated flare and outside the range of the smoke flow; determining the measured concentration based on the gas concentration measured at a second target position, wherein the second target position represents a position downwind of the flame of the elevated flare and within the range of the smoke flow, wherein the measured concentration represents the concentration of the exhaust gas after the combustion of the elevated flare after dilution with air; determining the initial concentration based on the exhaust gas concentration measured at the air inlet of the elevated flare, wherein the initial concentration represents the concentration of the exhaust gas that has not been burned by the elevated flare; when the actual concentration is determined based on the initial concentration and the measured concentration, determining the ratio of the initial concentration to the actual concentration as the combustion efficiency of the elevated flare, wherein the actual concentration represents the concentration of the exhaust gas after the combustion of the elevated flare without dilution with air.

[0005] Based on the above scheme, by measuring the exhaust gas concentration after combustion and diluted with air at the downwind port of the elevated flare flame, and then comparing it with the exhaust gas concentration before combustion measured at the air inlet of the elevated flare, the exhaust gas concentration after combustion without air dilution can be determined, and the actual combustion efficiency of the elevated flare can be accurately calculated.

[0006] In some possible embodiments, before determining the actual measured concentration based on the gas concentration measured at the second target position, the method further includes: controlling the system to rise to the first target position, and determining the measured gas concentration data as a reference concentration; controlling the system to rise a preset distance, and measuring the gas concentration in real time; and when the difference between the real-time measured gas concentration and the reference concentration meets a preset condition, determining the corresponding position of the system as the second target position.

[0007] Based on the above scheme, by controlling the system to rise from a first target position outside the smoke flow range, and measuring the gas concentration during the rising process to determine whether the system is within the smoke flow range, the actual measured concentration data can be accurately obtained, thereby improving the calculation accuracy of the elevated flare combustion efficiency.

[0008] In some possible embodiments, before determining the corresponding location of the system as the second target location, the method further includes: when the system is rising and the rate of change of the gas concentration measured in real time reaches a preset rate of change, determining the corresponding location of the system as a smoke flow boundary; determining the smoke flow range based on the smoke flow boundary; and determining the corresponding location of the system as the second target location when the difference between the gas concentration measured within the smoke flow range and the reference concentration reaches a preset difference.

[0009] Based on the above scheme, when the rate of change of the real-time measured gas concentration reaches the preset rate of change, it means that the measured exhaust gas concentration rises or falls rapidly, and the corresponding position is marked as the smoke flow boundary. The adjacent smoke flow boundary includes the smoke flow range. By measuring multiple gas concentration values ​​within the smoke flow range, the second target position can be accurately determined, thereby improving the accuracy of the measured concentration.

[0010] In some possible embodiments, the system is provided with a visual module, which is used to capture a smoke flow image; before determining the corresponding location of the system as a smoke flow boundary, the method further includes: acquiring a smoke flow image of the location of the system in real time during the ascent of the system; when the difference between the smoke flow image and the image captured at the first target location is greater than a reference value, determining the corresponding location of the system as a smoke flow boundary.

[0011] Based on the above scheme, the smoke flow is photographed and imaged by the visual module, and the smoke flow boundary is determined based on the smoke flow image, so that the user can intuitively determine whether the system is within the smoke flow range, and can also improve the speed and accuracy of determining the second target position.

[0012] In some possible embodiments, before determining the actual concentration based on the initial concentration and the measured concentration, the method further includes: determining an air dilution ratio based on the initial concentration and the measured concentration, the air dilution ratio characterizing the degree of dilution of the exhaust gas after the elevated flare combustion by the background air; determining a dilution concentration based on the air dilution ratio and the background concentration, the dilution concentration characterizing the concentration of the air that dilutes the exhaust gas after the elevated flare combustion; and determining the difference between the measured concentration and the dilution concentration as the actual concentration.

[0013] Based on the above scheme, the air dilution ratio is determined by the change in concentration, and the air dilution degree is determined based on the air dilution ratio. The actual concentration of the undiluted exhaust gas after combustion can be reversely deduced from the measured concentration, so as to accurately calculate the elevated flare combustion efficiency.

[0014] In some possible embodiments, the system is used to measure the concentration of carbon-containing gases in the air, and the carbon-containing gases include at least carbon monoxide, carbon dioxide, and non-methane total hydrocarbons; the measured concentration is determined based on the gas concentration measured at the second target position, including: measuring the concentration of the first target gas, and the first target gas includes carbon monoxide, carbon dioxide, and non-methane total hydrocarbons; based on the concentrations of each of the first target gases, the overall concentration of all the first target gases is determined, and the overall concentration is determined as the measured concentration.

[0015] Based on the above scheme, by measuring the main component gas in the exhaust gas, the redundancy of the system is reduced, which helps to improve the measurement calculation speed and reduce the cost of the system.

[0016] In some possible embodiments, the initial concentration is determined based on the concentration of the exhaust gas measured at the air inlet of the elevated flare, including: obtaining the concentration of a second target gas at the air inlet of the elevated flare, the second target gas at least including total hydrocarbon gas, and determining the concentration of the second target gas as the initial concentration.

[0017] Based on the above scheme, by measuring the total hydrocarbon gas at the air inlet to determine the initial concentration, the calculation difficulty can be reduced and the measurement calculation speed can be improved.

[0018] According to some other embodiments of the present disclosure, a tethered balloon carrier system is provided, which applies a method for detecting the combustion efficiency of an elevated flare as described in any one of the above embodiments, the system includes a carrier module, a measurement module and a data processing module, the carrier module includes a winch and a tethered balloon, the winch is connected to the tethered balloon via a traction line, the winch is used to wind the traction line to control the buoyancy height of the tethered balloon; the measurement module is arranged on the tethered balloon, the measurement module is used to measure the temperature, humidity, wind speed and concentration of exhaust gas after the combustion of the elevated flare; the data processing module is wirelessly connected to the measurement module, the data processing module is used to obtain the measurement data of the measurement module and calculate the combustion efficiency of the elevated flare.

[0019] Based on the above scheme, a measurement module is set on the tethered balloon to obtain the concentration data of the specified gas, and then sent to the data processing module through wireless communication for data processing and calculation. The system structure is simple and easy to implement.

[0020] In some possible embodiments, a carrying basket is connected to the bottom of the tethered balloon, the carrying basket is hollowed out, the measuring module is fixedly installed in the carrying basket, an exhaust fan is provided in the carrying basket, and the exhaust fan is used to suck the smoke flow outside the carrying basket to the measuring module.

[0021] Based on the above scheme, by setting up a carrying basket with a hollow structure, it helps to reduce the weight of the carrying basket, and the carrying basket is not easily affected by the airflow and shakes. The exhaust fan can draw the smoke flow to the measurement module, which can avoid inaccurate measurement due to the measurement module not being aligned with the wind direction, and help the measurement module to obtain data stably and improve the accuracy of the measurement.

[0022] In some possible embodiments, the system further includes a visual module, which is fixedly mounted in the carrying basket, and is used to capture images of smoke flows. The data processing module is wirelessly connected to the visual module, and the data processing module is further used to determine whether the carrying basket is within the range of the smoke flow based on images captured by the visual module.

[0023] Based on the above solution, the user can intuitively judge whether the carrying basket is within the smoke flow range based on the smoke flow image taken by the visual module, thereby ensuring the accuracy of the actual concentration measurement.

[0024] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0025] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions and advantages in the embodiments of this specification or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 A flowchart showing a method for detecting combustion efficiency of an elevated flare according to an embodiment of the present invention;

[0028] Figure 2 A flowchart showing the steps of a method for determining an actual concentration according to an embodiment of the present disclosure;

[0029] Figure 3 A flowchart showing the steps of a method for determining a second target position according to an embodiment of the present disclosure;

[0030] Figure 4 A flowchart showing another method for determining a second target position according to an embodiment of the present invention;

[0031] Figure 5 A system structure diagram of a tethered balloon carrier system according to an embodiment of the present invention is shown;

[0032] Figure 6 A structural block diagram of a measurement module according to an embodiment of the present invention is shown.

[0033] In the figure:

[0034] 1. Vehicle module; 11. Tethered balloon; 12. Winch; 13. Carrying basket; 2. Measurement module; 3. Data processing module; 4. Exhaust fan; 5. Vision module. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products, or devices.

[0037] Various exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0038] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0039] The term "and / or" herein is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set consisting of A, B, and C.

[0040] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0041] In order to facilitate understanding of the embodiments of the present disclosure, the following terms are defined and explained:

[0042] BC, black charcoal, commonly known as soft charcoal, also known as earth kiln charcoal, referred to as BC. The surface is pure black or with white powder that can be blown off.

[0043] NMHC, non-methane hydrocarbons, is defined as the value remaining after methane is deducted from the total hydrocarbon measurement result.

[0044] THC, the abbreviation of total hydrocarbons, is the abbreviation of the total amount of hydrocarbons contained in the gas. It refers to the sum of gaseous organic matter that responds on the gas chromatography hydrogen flame ionization detector under specified conditions.

[0045] VOCs, volatile organic compounds (English name: Volatile Organic Compounds), refer to organic compounds that have a high saturated vapor pressure (greater than 13.33 Pa), a low boiling point, a small molecular weight, and are easy to volatilize at room temperature under standard conditions.

[0046] Elevated flares are indispensable safety facilities for petrochemical enterprises. They are mainly used to deal with internal leaks such as safety valves connected to petrochemical factories, overpressure emissions during production, purge gas emissions during start-up and shutdown of equipment, and emergency emissions under accident conditions.

[0047] Combustion efficiency (CE) is an important indicator for detecting whether the volatile organic compounds (VOCs) in the elevated flare are fully burned and whether the emission meets the standard. However, unlike other chimney emission methods, the elevated flare combustion is not closed, and its emission port is in the flame. It is affected by the combustion temperature, the gas velocity of the elevated flare, and steam. It is difficult for traditional monitoring methods at home and abroad to achieve sampling and analysis of the elevated flare emission port. Only the sampling and detection data of the elevated flare inlet cannot accurately detect the combustion efficiency of the elevated flare, so it is urgent to design an accurate elevated flare combustion efficiency detection method.

[0048] In order to solve the above-mentioned technical problems, an embodiment of the present disclosure provides a method for detecting the combustion efficiency of an elevated flare. The method is applied to a tethered balloon carrier system. The system is implemented based on a tethered balloon and a measuring device. It is used to rise and float in the air and measure the concentration data of exhaust gas after the combustion of the elevated flare. Based on the function of the system to measure the exhaust gas concentration, the method determines the exhaust gas concentration after combustion by measuring the exhaust gas concentration at the downwind outlet of the elevated flare combustion flame, and then determines the combustion efficiency of the elevated flare in combination with the exhaust gas concentration before combustion measured at the air inlet of the elevated flare.

[0049] Figure 1 A flowchart of a method for detecting combustion efficiency of an elevated flare according to an embodiment of the present disclosure is shown. Figure 1 As shown, the method includes:

[0050] Step S101, determining a background concentration based on a gas concentration measured at a first target position, wherein the first target position represents a position downwind of an overhead flare burning flame and outside a smoke flow range.

[0051] Since the elevated flare burns the waste gas emitted by petrochemical enterprises and then releases it into the air, the waste gas released after combustion will mix with the air, that is, the air has a dilution effect on the released waste gas. In order to obtain the degree of dilution of the air, it is necessary to measure the air concentration that is not affected by the released waste gas. In addition, there are particulate matter in the released waste gas to form a smoke flow. Therefore, by measuring the gas concentration at a position outside the range of the smoke flow, the background air concentration can be obtained.

[0052] In this embodiment, the types of gases measured by the system are not limited, that is, the concentration of all gaseous substances in the air can be measured, or only the concentration of the main components can be measured, for example, only the main components of the air such as nitric oxide (NO), nitrogen dioxide (NO2), oxygen (O2), carbon monoxide (CO), and carbon dioxide (CO2) can be measured. Furthermore, since the main components of the exhaust gas released after the overhead flare combustion include carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), oxygen (O2), black carbon (BC) particles, etc., therefore, in order to avoid the error in the gas concentration measurement leading to inaccurate calculation of the final combustion efficiency, when measuring the background gas concentration, the concentration of volatile organic compounds and black carbon should also be measured to ensure the accurate measurement of the background concentration.

[0053] In this embodiment, the first target position may be a preset height position, or a position where a smokeless flow is determined by an operator visually or a measuring instrument. When controlling the tethered balloon vehicle system to ascend, it is also necessary to measure the wind speed and wind direction in real time to avoid inaccurate sampling and measurement caused by excessive wind speed and / or wind direction changes.

[0054] In a specific embodiment, when the wind direction is stable and the wind speed is less than 10m / s, the tethered balloon vehicle system is controlled to rise to a height of 50 meters downwind of the elevated torch burning flame, that is, the first target position is a preset height of 50 meters, and the control system stays at this height for several minutes, and measures the concentrations of nitric oxide (NO), nitrogen dioxide (NO2), oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), non-methane hydrocarbons (NMHC) and black carbon (BC), and calculates the background concentration based on the measured concentrations, and the background concentration represents the concentration of pollutants in the atmosphere. Among them, the concentration of non-methane hydrocarbons (NMHC) indicates the content of volatile organic compounds (VOCs).

[0055] Step S102, based on the gas concentration measured at the second target position, determine the measured concentration, the second target position represents a position downwind of the elevated flare flame and within the smoke flow range, and the measured concentration represents the concentration of the exhaust gas after the elevated flare combustion is diluted by air.

[0056] Based on the previous content, we can know that the elevated flare is used to burn and transform the waste gas emitted by petrochemical enterprises, so as to avoid the direct emission of harmful pollutants (mainly organic matter) into the air. During the combustion process, the waste gas first undergoes an oxidation-reduction reaction with the air, that is, air is mixed into the elevated flare to provide oxygen to assist combustion. The waste gas after combustion is discharged into the air and then mixed with the air for dilution. Therefore, the smoke flow actually observed is the product of the mixture of the waste gas after combustion and the air. The measured concentration determined based on the smoke flow concentration is also the concentration of the waste gas after combustion of the elevated flare after dilution with air.

[0057] Since the smoke flow after the burning of the elevated flare is affected by the height of the elevated flare itself, wind speed, ambient temperature and humidity and other parameters, the second target position is not a fixed position, and it is necessary to adjust the floating height of the above-mentioned tethered balloon carrier system so that the system moves from outside the smoke flow range to within the smoke flow range. This embodiment does not limit the specific operation method of the control system moving from the first target position to the second target position. For example, the operator can find and determine the smoke flow position based on visual inspection or visual instruments, and then manually remotely control the system to rise within the smoke flow range; or, the smoke flow position can be simulated and calculated based on the size of the elevated flare (height, inner diameter of the discharge port, etc.), wind speed, wind direction and other parameters, and then the second target position is determined based on the simulated smoke flow position, and the system automatically moves to the second target position; or, by setting a measuring instrument on the system, it is possible to detect and determine in real time whether the system is within the smoke flow range. When it is detected that the system is within the smoke flow range, the system automatically stops within the smoke flow range to obtain exhaust gas concentration data.

[0058] In this embodiment, the material objects measured at the second target position and the first target position should be consistent to ensure the accuracy of the subsequent combustion efficiency calculation, wherein the gaseous material measured at the second target position should include the components of the exhaust gas after the overhead flare combustion, namely carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), oxygen (O2), black carbon (BC) particles, etc., while the gaseous material measured at the first target position should include nitric oxide (NO), nitrogen dioxide (NO2), oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2) and other main components of the air. Therefore, the substances that the system needs to measure and analyze should include the concentrations of nitric oxide (NO), nitrogen dioxide (NO2), oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), non-methane total hydrocarbons (NMHC) and black carbon (BC), wherein the measured concentration of non-methane total hydrocarbons (NMHC) is used to characterize the content of volatile organic compounds (VOCs).

[0059] Step S103: determining an initial concentration based on the concentration of the exhaust gas measured at the air inlet of the elevated flare, where the initial concentration represents the concentration of the exhaust gas that has not been combusted by the elevated flare.

[0060] In this embodiment, while measuring the gas concentration inside and outside the smoke flow range of the downwind outlet of the elevated flare burning flame by the tethered balloon carrier system, it is also necessary to measure the gas concentration at the air inlet of the elevated flare, that is, the concentration of the unburned waste gas after the petrochemical enterprise is discharged, and the measured waste gas concentration is determined as the initial concentration. It should be understood that the measurement of the gas concentration at the air inlet of the elevated flare is based on a device other than the tethered balloon carrier system, for example, using an air bag to collect the inflow gas at the air inlet valve of the elevated flare and analyze the concentration, or directly obtaining the concentration information through the monitoring equipment on the pipeline connecting the air inlet of the elevated flare.

[0061] In some possible embodiments, the types of substances measured at the elevated flare gas inlet include total hydrocarbon gas and non-methane total hydrocarbons, that is, the second target gas includes total hydrocarbon gas and non-methane total hydrocarbons. By detecting the concentrations of the two separately, the initial concentration can be calculated more accurately.

[0062] Step S104, when the actual concentration is determined based on the initial concentration and the measured concentration, the ratio of the initial concentration to the actual concentration is determined as the elevated flare combustion efficiency, and the actual concentration represents the concentration of the exhaust gas after the elevated flare combustion without air dilution.

[0063] Based on the above steps, it can be seen that in the process of the elevated flare burning exhaust gas, air will be mixed in to help combustion, causing the exhaust gas concentration after combustion to decrease. Subsequently, the exhaust gas is discharged into the atmosphere and mixed with air, causing the concentration to further decrease. In addition, due to the structure of the elevated flare itself, the combustion of the elevated flare is not closed, and its discharge port is in the flame. The exhaust gas concentration after combustion cannot be directly measured by the instrument, that is, the above actual concentration cannot be directly measured. Only the exhaust gas concentration in the emitted smoke flow can be measured. Therefore, it is necessary to reversely deduce the actual concentration based on the measured concentration. Finally, the elevated flare combustion efficiency is determined based on the initial concentration and the actual concentration. The formula for the elevated flare combustion efficiency is:

[0064] F(%)=C i，初始浓度 / C i，实际浓度 , where C i，初始浓度 is the exhaust gas concentration without overhead flare combustion, C i，实际浓度 It is the concentration of the exhaust gas after the elevated flare combustion without air dilution, and F (%) is the combustion efficiency, that is, the ratio of the actual heat released by the exhaust gas to the theoretical complete heat released (actual heat released / complete heat released × 100%).

[0065] In this embodiment, the combustion efficiency of the elevated flare is not obtained by directly measuring the actual heat release, but is determined based on the change in pollutant concentration before and after combustion. In the traditional method, the combustion efficiency is calculated by the ratio of the actual heat release to the theoretical heat release. However, the actual heat release cannot be accurately measured in the elevated flare, so the method of inference estimation is adopted. In order to achieve accuracy, a complex calculation model and multiple experimental verifications are required. The indirect measurement method used for the combustion efficiency of the elevated flare in this embodiment comprehensively determines the combustion efficiency by detecting the pre-combustion data, the post-combustion data and the background concentration data. On the one hand, it can improve the measurement accuracy of the combustion efficiency of the elevated flare, and on the other hand, it can also reduce the difficulty of measurement and calculation and increase the speed of calculation. It should be understood that this embodiment does not limit the combustion efficiency of the elevated flare to be fixed as the ratio of the initial concentration to the actual concentration. There are differences in the relationship between the combustion efficiency and the change in pollutant concentration of different elevated flares. The measurement personnel can reasonably adjust the calculation formula of the combustion efficiency of the elevated flare according to the actual measurement object. For example, in one possible implementation, the formula for the combustion efficiency of the elevated flare is:

[0066] F (%) = k × C i，初始浓度 / C i，实际浓度 , where k is the proportionality coefficient;

[0067] Alternatively, in another possible implementation, the elevated flare combustion efficiency formula is:

[0068] F (%) = k × C i，初始浓度 / C i，实际浓度 +b, where k is the proportionality coefficient and b is a constant.

[0069] This embodiment does not limit the method of inferring the actual concentration from the measured concentration. For example, the dilution ratio can be selected based on experience. The dilution ratio represents the degree of dilution of the post-combustion exhaust gas by air. The concentration of the post-combustion exhaust gas can be calculated based on the gas concentration corresponding to the measured carbon concentration and the dilution coefficient. Alternatively, an intelligent algorithm can be used to establish a fluid model, and then the post-combustion exhaust gas concentration can be confirmed based on the actual measured gas concentration.

[0070] In some embodiments, an air dilution ratio method may be used to specifically calculate the air dilution ratio, and the calculation of the air dilution ratio may be divided into two methods: a carbon dilution ratio and an oxygen dilution ratio.

[0071] In a specific embodiment, the oxygen dilution ratio is calculated using oxygen atoms. Burning oxygen will react to form other oxides, such as CO2, CO, H2O, NO, NO2 and SO2, but the oxygen atoms are still conserved after conversion, so the air dilution ratio is estimated. The source of oxygen atoms can be divided into two parts: exhaust gas and air. The concentration of oxygen atoms in the atmosphere is mainly oxygen, and its concentration does not change much. Assuming that the exhaust gas supplied to the elevated flare does not contain oxygen or oxide components, the oxygen atom concentration will decrease after the exhaust gas is mixed with air. The air dilution effect is estimated by the difference between oxygen atoms in the smoke flow and the atmospheric background. The oxygen dilution ratio calculation formula is as follows:

[0072] α （氧稀释比例） = (the sum of oxygen atomic contents of all components monitored downwind) / 0.42.

[0073] In another specific embodiment, the carbon dilution ratio can be obtained by the carbon dilution ratio based on the difference in carbon concentration at the inlet and outlet of the elevated flare. The inlet carbon concentration is the carbon concentration of total hydrocarbon compounds (THC) in the exhaust gas at the inlet of the elevated flare, and the outlet carbon concentration is the carbon concentration of carbon-containing gas in the flue gas at the downwind outlet of the elevated flare, which can be divided into carbon dioxide (CO2), carbon monoxide (CO), non-methane total hydrocarbons (NMHC) and black carbon (BC). The carbon atom concentration at the observation point (second target position) can be determined by measuring the concentration of the above four pollutants. The carbon-containing substances produced by combustion are lower in the background concentration, so the carbon concentration of the background air is ignored. Therefore, the carbon dilution ratio can be calculated based on the following formula:

[0074] β （碳稀释浓度） =1-(CO2+CO+NMHC+BC) downwind monitoring concentration / inlet THC concentration.

[0075] Based on the above formula, the carbon dilution ratio can be understood as part of the carbon-containing matter in the exhaust gas after combustion entering the atmosphere, resulting in the outlet carbon concentration being lower than the inlet carbon concentration.

[0076] Furthermore, when the air dilution ratio is calculated by adopting the carbon dilution ratio method, the carbon concentration needs to be determined based on the measured gas concentration. Therefore, the above-mentioned tethered balloon carrier system can be configured to measure the concentration of carbon-containing gas in the air, wherein the carbon-containing gas includes at least carbon monoxide (CO), carbon dioxide (CO2) and non-methane hydrocarbons (NMHC), and the step of determining the measured carbon concentration includes: determining the carbon concentration of the first target gas based on the concentration of the measured target gas, the first target gas includes: carbon monoxide, carbon dioxide, non-methane hydrocarbons; determining the overall carbon concentration of all the first target gases based on the carbon concentration of each first target gas, and determining the overall carbon concentration as the measured carbon concentration. That is to say, according to the gas concentrations of carbon monoxide, carbon dioxide, and non-methane hydrocarbons, the carbon concentrations of carbon monoxide, carbon dioxide, and non-methane hydrocarbons are determined respectively, and then the overall carbon concentration is calculated based on each carbon concentration.

[0077] Correspondingly, when measuring the initial concentration, the intake carbon concentration must also be calculated. Therefore, the intake carbon concentration is determined based on the concentration of the exhaust gas measured at the air inlet of the elevated flare, including: obtaining the concentration of the second target gas at the air inlet of the elevated flare, the second target gas at least including total hydrocarbon gas; determining the carbon concentration of the second target gas based on the concentration of the second target gas, and determining the carbon concentration of the second target gas as the intake carbon concentration.

[0078] Based on the above method for determining the air dilution ratio, the actual concentration can be determined as follows: Figure 2 As shown, including:

[0079] Step S201: Determine the air dilution ratio based on the initial concentration and the measured concentration. The air dilution ratio represents the dilution degree of the exhaust gas after the overhead flare combustion by the background air.

[0080] Step S202: determining a dilution concentration based on the carbon dilution ratio and the background concentration, wherein the dilution concentration represents the concentration of air that dilutes the exhaust gas after the elevated flare combustion.

[0081] Step S203: determine the difference between the measured concentration and the diluted concentration as the actual concentration.

[0082] In this embodiment, the relationship between the measured concentration, the actual concentration and the background concentration can be expressed as the following formula:

[0083] C i，实测浓度 =C i，实际浓度 +γC i，背景浓度 , where C i，实测浓度 is the exhaust gas concentration measured at the second target position, in ppm; γ is the air dilution ratio, in %; C i，实际浓度 is the actual exhaust gas concentration after the elevated flare combustion, in ppm; C i，背景浓度is the background concentration, i.e. the atmospheric concentration not affected by exhaust gas, in ppm. Based on the above formula, we know that γC i，背景浓度 This is the above dilution concentration.

[0084] The above embodiment has introduced a scheme of measuring gas concentration at the downwind outlet of an elevated flare and calculating the measured concentration, thereby inferring the actual concentration. It is understandable that the selection of the second target position affects the accuracy of the measured concentration, and further affects the accuracy of calculating the combustion efficiency of the elevated flare. Figure 3 The method for determining the second target position according to an embodiment of the present disclosure is shown. Before step S102, the method further includes:

[0085] Step S301: The control system rises to a first target position and determines the measured gas concentration data as a reference concentration.

[0086] Step S302: The control system rises by a preset distance and measures the gas concentration in real time.

[0087] Step S303: When the difference between the real-time measured gas concentration and the reference concentration meets a preset condition, the location of the corresponding system is determined as the second target location.

[0088] In this embodiment, the control system first rises to the first target position outside the smoke flow range to obtain a reference concentration, and then the control system rises and synchronously measures the exhaust gas concentration in the environment. When a sharp rise in the exhaust gas concentration is detected, it is considered that the system has entered the smoke flow range. This embodiment does not impose specific restrictions on the preset conditions. It should be understood that the concentration difference of the preset conditions is related to factors such as the size of the elevated flare, the intake air concentration, and the intake air speed. Therefore, the preset conditions should be reasonably set according to the actual measurement object. In addition, in step S302, the real-time measurement of gas concentration can also be replaced by measuring the concentration according to a fixed period, or variable frequency sampling measurement, that is, adjusting the length of the measurement period according to the measured gas concentration value, thereby ensuring measurement accuracy while saving electricity and reducing storage costs.

[0089] In some specific embodiments, please refer to Figure 4 Before determining the location of the corresponding system as the second target location in step S303, the method further includes:

[0090] Step S401: When the system is ascending and the rate of change of the gas concentration measured in real time reaches a preset rate of change, the location of the corresponding system is determined as the smoke flow boundary.

[0091] Step S402: Determine the smoke flow range based on the smoke flow boundary.

[0092] Step S403: When the difference between the gas concentration measured within the smoke flow range and the reference concentration reaches a preset difference, the location of the corresponding system is determined as the second target location.

[0093] Based on the above steps, whether the system has entered the smoke flow is determined according to the measured concentration change rate. When the measured substance concentration shows a sudden rise and the concentration change rate reaches the preset change rate, it can be preliminarily determined that the system has reached the smoke flow range, and the corresponding position is set as the smoke flow boundary. The system is then controlled to rise and another smoke flow boundary is found. The range between the two smoke flow boundaries is determined as the smoke flow range. The control system performs multiple measurements within the smoke flow range until the second target position is found.

[0094] Furthermore, in some possible embodiments, when the difference between the measured gas concentration and the reference concentration at multiple height positions within the smoke flow range reaches a preset difference, the position with the highest concentration can be selected as the second target position, and the highest concentration is the measured concentration; or, the average height position of several positions can be selected as the second target position, and the average concentration value of several measured concentration values ​​can be used as the measured concentration.

[0095] In some embodiments, in order to ensure the measurement accuracy of the measured concentration, the smoke flow range can also be confirmed by image recognition, that is, the tethered balloon carrier system is provided with a visual module, and the visual module is used to capture the smoke flow image. By analyzing and processing the smoke flow image, the smoke flow boundary and / or smoke flow range can be determined. Specifically, taking the determination of the smoke flow boundary as an example, the determination step includes: during the ascent of the system, obtaining the smoke flow image of the system's location in real time; when the difference between the smoke flow image and the image captured at the first target position is greater than a reference value, the corresponding system location is determined as the smoke flow boundary. Similarly, it is also possible to directly determine whether the current position is within the smoke flow range based on the analysis results of the smoke flow image.

[0096] The above embodiments have described in detail a method for detecting the combustion efficiency of an elevated flare disclosed in the present invention. The present embodiment also provides a tethered balloon carrier system, which uses a method for detecting the combustion efficiency of an elevated flare as described in any of the above embodiments. Figure 5 The system includes a vehicle module 1, a measurement module 2 and a data processing module 3, wherein the vehicle module 1 includes a winch 12 and a tethered balloon 11, the winch 12 is connected to the tethered balloon 11 through a traction line, and the winch 12 is used to wind the traction line to control the buoyancy height of the tethered balloon 11.

[0097] In a specific embodiment, the tethered balloon 11 is a balloon with a diameter of 3 meters, and is powered by helium filling to provide buoyancy. The tethered balloon 11 can carry 5 kg of equipment. The tethered balloon 11 and the winch 12 are fixed with high-strength fiber lines, and the electric reel in the winch 12 controls the height of the tethered balloon 11 to achieve a lifting effect.

[0098] The measuring module 2 is disposed on the tethered balloon 11, and the measuring module 2 is used to measure the temperature, humidity, wind speed, and the concentration of the exhaust gas after the overhead flare combustion. Figure 6 As shown, the measurement module 2 includes a temperature unit, a humidity unit, a wind speed unit, an exhaust gas concentration unit and a communication unit.

[0099] The data processing module 3 is wirelessly connected to the measuring module 2, and the data processing module 3 is used to obtain the measurement data of the measuring module 2 and calculate the combustion efficiency of the elevated flare. The data processing module 3 is separated from the tethered balloon 11. In some specific embodiments, such as Figure 5 As shown, the data processing module 3 is integrated in the ground monitoring system. In addition, the data processing module 3 is also connected to the measurement system of the elevated flare in communication. Specifically, the data processing module 3 is connected to the air bag device at the air inlet valve port of the elevated flare in communication to obtain the exhaust gas concentration data of the air inlet port of the elevated flare.

[0100] Since the tethered balloon 11 is easily affected by wind and shakes, if the measurement module 2 is directly set on the tethered balloon 11, the data measured by the measurement module 2 will be inaccurate. In order to improve the stability of the measurement, in the embodiment of the present disclosure, a carrying basket 13 is connected to the bottom of the tethered balloon 11. The carrying basket 13 is a hollow design, and the measurement module 2 is fixedly installed in the carrying basket 13. The carrying basket 13 based on the hollow setting can improve the stability of the measurement module 2, thereby improving the accuracy of the measurement data. In addition, the setting of the carrying basket 13 also helps to control the load of the system and make it work smoothly.

[0101] Furthermore, an exhaust fan 4 is also provided in the carrying basket 13. The hollow carrying basket 13 presents a mesh structure. The exhaust fan 4 is used to suck the smoke flow outside the carrying basket 13 and send it to the measuring module 2. This can solve the problem of inaccurate measurement data when the measuring module 2 is not aligned with the wind direction. When the measuring module 2 is not aligned with the wind direction, there is no need to specially control the steering of the tethered balloon 11, thereby reducing the difficulty of system control during measurement.

[0102] In some embodiments, the system also includes a visual module 5, which is fixedly installed in the carrying basket 13. The visual module 5 is used to capture the smoke flow image. The data processing module 3 is wirelessly connected to the visual module 5. The data processing module 3 is also used to determine whether the carrying basket 13 is within the smoke flow range based on the image captured by the visual module 5.

[0103] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for detecting the combustion efficiency of an elevated flare, characterized in that: Applied to a tethered balloon vehicle system, the system is used to float up into the air and measure the concentration data of the exhaust gas after the combustion of an elevated flare; the method comprises: determining a background concentration based on a gas concentration measured at a first target location, the first target location representing a location downwind of an overhead flare burning flame and outside of a smoke plume; Determining a measured concentration based on a gas concentration measured at a second target position, wherein the second target position represents a position downwind of the elevated flare combustion flame and within the range of the smoke flow, and the measured concentration represents the concentration of the exhaust gas after the elevated flare combustion is diluted by air; Determining an initial concentration based on the concentration of the exhaust gas measured at the air inlet of the elevated flare, the initial concentration representing the concentration of the exhaust gas that has not been combusted by the elevated flare; Based on the initial concentration and the measured concentration, determining an air dilution ratio, wherein the air dilution ratio represents a degree of dilution of the exhaust gas after the overhead flare combustion by the background air; Determine a dilution concentration based on the air dilution ratio and the background concentration, wherein the dilution concentration represents the concentration of air that dilutes the exhaust gas after the elevated flare combustion; Determine the difference between the measured concentration and the diluted concentration as the actual concentration; The ratio of the initial concentration to the actual concentration is determined as the elevated flare combustion efficiency, and the actual concentration represents the concentration of the exhaust gas after the elevated flare combustion without being diluted with air.

2. The method according to claim 1, characterized in that Before determining the measured concentration based on the gas concentration measured at the second target location, the method further includes: controlling the system to rise to the first target position, and determining the measured gas concentration data as a reference concentration; Control the system to rise a preset distance and measure the gas concentration in real time; When the difference between the real-time measured gas concentration and the reference concentration meets a preset condition, the corresponding location of the system is determined as the second target location.

3. The method according to claim 2, characterized in that Before determining the location of the corresponding system as the second target location, the method further includes: During the process of the system ascending, when the rate of change of the gas concentration measured in real time reaches a preset rate of change, the corresponding position of the system is determined as the smoke flow boundary; Based on the smoke plume boundary, determining the smoke plume range; When the difference between the gas concentration measured within the smoke flow range and the reference concentration reaches a preset difference, the corresponding location of the system is determined as the second target location.

4. The method according to claim 3, characterized in that The system is provided with a visual module, and the visual module is used to capture a smoke flow picture; before determining the location of the corresponding system as the smoke flow boundary, the method further includes: During the ascent of the system, a smoke flow image of the location of the system is obtained in real time; When the difference between the smoke flow picture and the picture taken at the first target position is greater than a reference value, the corresponding position of the system is determined as a smoke flow boundary.

5. The method according to claim 1, characterized in that The system is used to measure the concentration of carbon-containing gas in the air, wherein the carbon-containing gas includes at least carbon monoxide, carbon dioxide, and non-methane total hydrocarbons; the actual concentration is determined based on the gas concentration measured at the second target position, including: Measuring the concentration of a first target gas, wherein the first target gas includes: carbon monoxide, carbon dioxide, and non-methane total hydrocarbons; Based on the concentrations of the respective first target gases, an overall concentration of all the first target gases is determined, and the overall concentration is determined as the measured concentration.

6. The method according to claim 5, characterized in that The method of determining the initial concentration based on the concentration of the exhaust gas measured at the air inlet of the elevated flare comprises: The concentration of a second target gas at the gas inlet of the elevated flare is obtained, where the second target gas at least includes total hydrocarbon gas, and the concentration of the second target gas is determined as an initial concentration.

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