Method for estimating concentration of volatile organic compounds under alarm sensitivity balance

Abstract

The application discloses a volatile organic compound concentration estimation method under alarm sensitivity balance, provides a new VOCs concentration estimation method, sets the ladder height dynamically in each data collection period, scientifically sets the VOCs concentration detection frequency, and according to the accurate VOCs concentration detected at the second level and the VOCs concentration detected at the first level, adjusts and sets the position of the VOCs concentration detection equipment at the first level dynamically in each detection period, considers the influence of the different diffusion speeds of different types of VOCs at each second level in each detection period on the accuracy of the VOCs concentration detected at the first level, then constructs a period concentration site floating diagram to estimate the VOCs concentration, and according to the estimation result, whether the VOCs concentration exceeds the standard is judged, a balance between the VOCs concentration estimation accuracy and the alarm sensitivity is found, and the requirements of the background technology on the alarm sensitivity in the specific scene can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of VOCs concentration detection, and particularly relates to a volatile organic compound concentration estimation method under alarm sensitivity balance. BACKGROUND

[0002] In China, VOCs (volatile organic compounds) refers to organic compounds with a saturated vapor pressure greater than 70 Pa at room temperature, or a boiling point below 260 DEG C at normal pressure, or a vapor pressure greater than or equal to 10 Pa at 20 DEG C and having volatility. Most VOCs have a special smell that makes people uncomfortable, and have toxicity, irritation, teratogenicity and carcinogenicity, especially benzene, toluene and formaldehyde, which can cause great harm to human health. Therefore, it is very important to detect VOCs concentration and timely alarm when it exceeds the standard.

[0003] Generally speaking, the higher the accuracy of VOCs concentration detection, the more timely the alarm, and people have more time to respond to VOCs concentration exceeding the standard. In the existing scheme, in order to ensure the accuracy of VOCs concentration detection, more VOCs concentration detection devices are arranged at more places and the VOCs concentration detection frequency is increased. For example, as shown in the factory space of Fig. 1, multiple VOCs concentration detection devices are arranged above each VOCs source b1, b3, b4, P1, P3, P4, etc., and more VOCs concentration detection data is collected at more time points by increasing the VOCs concentration detection frequency, and alarm is given as long as VOCs concentration exceeds the standard at a certain time point. Figure 6 However, the existing scheme for VOCs concentration detection and over-standard alarm has the following technical problems:

[0004] 1. The data basis for VOCs concentration over-standard alarm is the VOCs concentration data directly measured by the VOCs concentration detection devices arranged at each place at each detection time. As long as the VOCs concentration exceeds the standard at any detection time, the alarm is too sensitive, which is unacceptable for factories with good ventilation conditions.

[0005] In order to solve the problem of too sensitive alarm, the technical field usually reduces the VOCs concentration detection frequency, but the following technical problems are caused:

[0006] 2. If multiple types of VOCs are generated within a factory, these different types of VOCs have varying diffusion rates at different locations within the factory. Under the same ventilation conditions, the time required for VOCs with different diffusion rates to decrease to acceptable concentrations will differ. Therefore, it is difficult to determine the appropriate detection frequency for each detection device specifically designed to monitor the concentration of one or more types of VOCs, whether to unify it or reduce it individually. Consequently, it is challenging to strike a balance between ensuring accuracy in concentration detection and reducing warning sensitivity when reducing the VOCs concentration detection frequency.

[0007] In addition, the existing solutions mentioned above also have the following problems:

[0008] 3. In the existing scheme, the basis for VOCs concentration exceeding the standard early warning analysis is each VOCs concentration detection device deployed at a designated site. When the number of VOCs concentration detection devices is large, the number of data objects for early warning analysis is also large. The early warning analysis process requires a larger amount of calculation and takes longer. Unnecessary early warning accuracy has actually extended the early warning time.

[0009] In summary, for the specific scenario of VOCs concentration exceeding the standard in well-ventilated factories, the more accurate the VOCs concentration data used as the basis for the warning, the better. Using VOCs concentration data obtained through direct measurement as the sole basis for VOCs concentration exceeding the standard can easily lead to excessively high alarm sensitivity, resulting in a counterproductive warning effect. On the other hand, the "one-size-fits-all" approach of reducing the VOCs concentration detection frequency to lower alarm sensitivity is problematic. Since different types of VOCs typically have different diffusion rates in different spaces within the factory at different times, it is difficult to determine the appropriate detection frequency for the detection equipment used to detect different types of VOCs concentrations. In other words, it is impossible to find a balance between ensuring the accuracy of VOCs concentration exceeding the standard warning and reducing warning sensitivity. Summary of the Invention

[0010] This invention provides a method for estimating volatile organic compound (VOC) concentration while maintaining alarm sensitivity. It offers a novel VOCs concentration estimation method by dynamically setting a stepped height in each data acquisition cycle to scientifically configure the VOCs concentration detection frequency. Based on the accurate VOCs concentration detected at the secondary height and the VOCs concentration detected at the primary height, the method dynamically adjusts the position of the VOCs concentration detection device at the primary height in each detection cycle. This considers the impact of different diffusion rates of different types of VOCs at each secondary height in each detection cycle on the accuracy of VOCs concentration detection at the primary height. Then, a periodic concentration site fluctuation map is constructed to estimate the VOCs concentration. The estimation results are used to determine whether the VOCs concentration exceeds the standard. This method strikes a balance between ensuring the accuracy of VOCs concentration estimation and the sensitivity of the early warning system, meeting the alarm sensitivity requirements for this specific scenario described in the background section.

[0011] The present invention adopts the following technical solution:

[0012] A method for estimating volatile organic compound concentration under alarm sensitivity equilibrium is provided, comprising the following steps:

[0013] S1, extract the top 'a' points from the dynamically updated periodic concentration locus map corresponding to each type of VOCs gas i for a specified time period.

[0014] S2, obtain the position at time t2 of each k+1 period within the specified time period at each of the specified sites. Concentration of each VOCs gas i collected at the site

[0015] S3, calculate the average gas concentration of each VOCs gas i during the specified time period. As the concentration estimate of VOCs gas of type i, A represents the number of the top a.

[0016] S4, determine whether the concentration estimation result of at least one VOCs gas of type i exceeds the standard.

[0017] If so, proceed with the tracing process for the VOCs source causing the type i concentration to exceed the standard;

[0018] If not, the traceability process will not be initiated.

[0019] Preferably, the factory space is divided into several grids g, each grid g having a longitudinal space from the ground to the roof of the factory. The first point corresponding to each binding point in the periodic concentration site floating map is set at the first level of the longitudinal space of the corresponding grid g.

[0020] Preferably, at least one second site is further provided in the longitudinal space of each grid g. Each second site in the grid g is located at a secondary height above the corresponding VOCs source. The secondary height of each second site in the space of the grid g is fixed, while the primary height of the first site in the space of the grid g is dynamically adjusted according to the VOCs detection cycle. The method for adjusting the primary height in the k+1 cycle is as follows: the height difference between each second site and the first site in the longitudinal space of the grid g It is calculated using the following formula (1):

[0021]

[0022] In formula (1), m represents the number of the m-th second site with a secondary height set in the grid g;

[0023] M represents the number of the second sites set within the grid g;

[0024] This represents the maximum rate at which VOCs gas diffuses from the m-th second site within the grid g during period k;

[0025] Δt is the allowed diffusion time from the second site, and Δt is the time difference between time t2 and time t1 of data acquisition in each period k;

[0026] It is calculated using the following formula (2):

[0027]

[0028] In formula (2), This represents the rate at which VOCs gas of type i diffuses from the m-th second site within period k;

[0029] I represents the number of VOCs gas types diffusing from the m-th second site.

[0030] As a preferred option The experimental diffusion rate of type i VOCs gas from the second site m in the grid g is defined as follows: in an experimental scenario with the same factory environment, at time t1 of period k at the second site m in the same grid g, the same concentration of type i VOCs gas is detected at that site, and at this time the concentration of type i VOCs gas at other spatial sites in the grid g except for the second site m is "0".

[0031] Preferably, the periodic concentration site floating map is constructed using the following method steps:

[0032] L1, at time t1 of each k-cycle in the specified time period, acquire the VOCs gas generating device in each grid g at the secondary height. The corresponding site The concentrations of each of the VOCs gases i collected at the site

[0033] L2, in each In the process, the gas concentrations with the highest concentration u are extracted to form a gas concentration set.

[0034] L3, judgment Does the concentration of each gas exceed its corresponding concentration threshold?

[0035] If so, then proceed to time t1 of period k+1 to process the grid g containing the first-level height. site The process of adjusting the setting position, after completing the position adjustment, yields the location. At the first level of the k+1 cycle Then proceed to step L4, the site Also updated to site

[0036] If not, then maintain the site for period k+1. The setting position is the same as the setting position in the k-cycle;

[0037] L4, at time t2 of each period of the specified time period, from the point where the position adjustment is completed. The concentration of each VOCs gas i was collected at the site. and form sites -Grid g-Time t2 of period k+1-Collected concentrations The binding relationship is determined, and then this binding relationship is used as the binding point. The t2 time of each period and the grid g are respectively the horizontal and vertical coordinates of the binding point in the XY axis coordinate system. The binding points are then plotted in the XY axis coordinate system to form the periodic concentration site floating map.

[0038] Preferably, in step L3, the position is dynamically adjusted at time t1 of period k+1. Location includes to The horizontal position is adjusted, and the specific adjustment method includes the following steps:

[0039] A1, obtain the first-level height of the grid g at time t2 within the specified time period k. The concentrations of the top VOCs gases detected at u

[0040] A2, obtain the secondary height of each grid g at time t1 within period k+1 of the specified time period. Concentration of each VOC gas i detected at the location And extract the concentrations of VOCs gas of the same type as the top u obtained in step A1. Each VOCs-generating site b in the grid g has a corresponding secondary height.

[0041] A3. For each type of VOCs gas u obtained in steps A1-A2, calculate the concentration difference.

[0042] A4, according to Calculate the diffusion factor u for each type of VOCs gas;

[0043] A5, based on the calculated diffusion factor, the site is located within a preset time range after time t1 in period k+1. The horizontal position is adjusted to the site.

[0044] Preferably, in step A4, the diffusion factor of each type of VOC gas u is calculated using the following formula (3):

[0045]

[0046] In formula (3), The diffusion factor represents the diffusion factor of VOCs gas of type u generated in grid g at time t1 of period k+1;

[0047] U indicates to proceed The number of VOCs gas types calculated.

[0048] As a preferred option, the site The horizontal position is adjusted to the site. The method includes the following steps:

[0049] A51, Identify the concentrations obtained in step A2 that are involved in the concentration difference calculation in step A3. The corresponding VOCs gas generation site O u As a site The basis for adjusting the horizontal position;

[0050] A52, Horizontally move the location And calculate the moved site O S With each O u distance

[0051] A53, calculate each of the distances. Distance ratio

[0052] A54, determine each of the aforementioned distance ratios Does it satisfy the corresponding diffusion factor? proportional relationship,

[0053] If so, then the site O S The site after horizontal position adjustment And terminate the position adjustment process;

[0054] If not, proceed to step A55;

[0055] A55, determine whether the preset allowable time for position movement has been reached.

[0056] If so, then via the aforementioned site O S Move back to Location;

[0057] If not, return to step A52 and continue moving the site horizontally.

[0058] In step A53, the distance ratio is calculated using the following formula (4).

[0059]

[0060] Preferably, the distance ratio described in step A54 Satisfying the corresponding diffusion factor The proportional relationship is:

[0061] judge Has it fallen into The corresponding factor value range,

[0062] If so, then determine and Satisfy the proportional relationship;

[0063] If not, then determine and The proportional relationship is not satisfied.

[0064] Preferably, the traceability process in step S4 includes the following steps:

[0065] B1, based on the calculation And are non-zero values The corresponding site Level 1 height Obtain the height of each of the first-level heights Associated secondary heights

[0066] B2, obtain the secondary altitudes obtained in step B1 at time t1 of each period k in the specified time period. The VOCs gas types collected at the site are determined, and it is determined whether type i is included.

[0067] If so, then corresponding sites Add to the list of locations to be flagged for alarm purposes;

[0068] If not, then not The corresponding site Add to the list of locations to be flagged for alarm;

[0069] B3, based on pre-constructed sites -The binding relationship between the VOCs gas generating device and the grid g where the VOCs generating device is located is matched to identify the VOCs generating device bound to each location in the list of potential alarm locations and the grid g corresponding to the matched VOCs generating device, and an alarm is triggered.

[0070] This invention provides a novel method for estimating VOC concentrations. By dynamically setting the step height in each data acquisition cycle, the method scientifically sets the VOC concentration detection frequency. Based on the accurate VOC concentration detected at the secondary height and the VOC concentration detected at the primary height, the method dynamically adjusts the position of the VOC concentration detection device at the primary height in each detection cycle. This considers the impact of different diffusion rates of different types of VOCs at each secondary height in each detection cycle on the accuracy of VOC concentration detection at the primary height. Then, a periodic concentration site fluctuation map is constructed to estimate the VOC concentration. The estimation results are used to determine whether the VOC concentration exceeds the standard. This method strikes a balance between ensuring the accuracy of VOC concentration estimation and the sensitivity of early warning, and can meet the alarm sensitivity requirements of the specific scenario described in the background art. Attached Figure Description

[0071] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0072] Figure 1 This is a flowchart illustrating the implementation steps of a method for estimating volatile organic compound concentration under alarm sensitivity balance provided in an embodiment of the present invention.

[0073] Figure 2 This is a schematic diagram of the VOCs concentration collection cycle within a specified time period;

[0074] Figure 3 It is a schematic diagram of dividing the interior space of the factory into several grids;

[0075] Figure 4 This is an example diagram of a periodic concentration site fluctuation chart associated with a specified time period;

[0076] Figure 5 This is an example diagram showing the horizontal position adjustment of the first-level height set above each grid g;

[0077] Figure 6 This is an example diagram of VOCs concentration detection equipment deployed within a factory space using existing methods. Detailed Implementation

[0078] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0079] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0080] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0081] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0082] This invention provides a method for estimating volatile organic compound concentration under alarm sensitivity equilibrium, such as... Figure 1 As shown, the steps include:

[0083] S1, extract the top 'a' points from the dynamically updated periodic concentration locus map corresponding to each type of VOCs gas i for a specified time period.

[0084] S2, obtain the position of each point at time t2 in each k+1 period within the specified time period. Concentration of each VOCs gas i collected at the site

[0085] S3, Calculate the average gas concentration of each VOCs gas i within the specified time period. As the concentration estimate of VOCs gas of type i, A represents the number of the top a.

[0086] S4, determine whether the concentration estimation result of at least one VOCs gas of type i exceeds the standard.

[0087] If so, proceed with the tracing process for the VOCs source causing the type i concentration to exceed the standard;

[0088] If not, the traceability process will not be initiated.

[0089] It should be noted here that the specified time period is, for example, 9:00 AM to 9:30 AM, a 30-minute period. Furthermore, this 30-minute period is further divided into multiple sub-segments, such as... Figure 2 The data acquisition cycle shown includes two data acquisition points, t1 and t2. One data acquisition cycle is from point "0" to point t1 to point t2. Then, in the next data acquisition cycle, time t2 of the previous cycle is taken as point "0", and a new data acquisition cycle begins, starting from point "0" again and continuing with time t1 to point t2. A specified time period includes K cycles.

[0090] Constructing a periodic concentration site fluctuation map is key to solving the technical problem this invention aims to address, and its main objectives include:

[0091] 1. The binding points plotted in the periodic concentration site floating map correspond to first sites with a first-level height. Each first site with a first-level height corresponds to a grid within the factory space, and there is a one-to-many correspondence between each second site with a second-level height located above each VOCs generation source within the corresponding grid. In this invention, the VOCs concentration of i is estimated (average value is taken) based on the concentration bound to the binding points in the periodic concentration site floating map (i.e., the concentration of VOCs gas i detected from the first site with a first-level height in each data acquisition cycle within a specified time period). The estimation considers the diffusion capacity of VOCs gas *i* in the longitudinal direction of space, represented by the gradient height dynamically adjusted in each cycle. Furthermore, using the estimation results as the data basis for VOCs concentration exceedance warnings avoids the technical problem of excessive warning sensitivity compared to directly using the VOCs concentration detected at each second site with a secondary height. By dynamically adjusting the gradient height, a balance is struck between warning accuracy and sensitivity, meeting the specific requirements for VOCs warning sensitivity and accuracy described in the background. Moreover, the first and second sites have a "one-to-many" relationship; using the VOCs concentration detected at the first site for concentration estimation and warning analysis significantly reduces the amount of data to be analyzed, correspondingly reducing the computational load during the warning process and resulting in a faster warning response.

[0092] 2. Different VOCs sources in each grid will produce the same or different amounts of various VOCs gases at different times. Due to the different concentration differences, the different VOCs gases produced at different times will have different diffusion rates at different locations in the horizontal and vertical space of different grids. To ensure the accuracy of VOCs concentration detection, the location of the VOCs concentration detection device must be matched to the diffusion rate of the detected object. For example, with a fixed detection period, at time t1 of a certain period, there is a definite concentration difference between the VOCs gas of type i generated from source A and spatial site B. If VOCs gas of type i with a concentration of X continues to be generated from source A, then, under this concentration difference, the diffusion rate of this VOCs gas with concentration X from source A to spatial site B is assumed to be Sx. Furthermore, it is necessary to detect this VOCs gas generated from source A at time t2 of the same period (time t1 is before time t2). Therefore, the height of the VOCs concentration detection device to be placed at spatial site B from source A should generally not exceed the product of Sx and (t2-t1). Otherwise, the continued generation of VOCs gas may not be detected at time t2. However, this height should not be set too low either, as setting it too low will weaken the influence of the diffusion capacity of the VOCs gas itself on the accuracy of concentration detection. The height between source A and spatial location B of the VOCs concentration detection device is referred to as the "secondary height" in this embodiment. To scientifically set this secondary height, it is necessary to consider the diffusion rates of different VOCs gases generated at different time points at different locations in the horizontal and vertical spaces of different grids. This diffusion rate is related to the concentration difference between source A and spatial location B. Since the quantity, type, and concentration of VOCs generated in each cycle are usually different, the concentration difference in each cycle is difficult to calculate accurately. Therefore, the process of setting the secondary height is very complicated. Therefore, in this embodiment, the secondary height of the VOCs concentration detection device positioned above each VOCs source is fixed. The fixed secondary height can be achieved as follows: a VOCs source within grid g generates VOCs gas i at time t1, and it is assumed that the concentration of type i VOCs gas at other spatial locations within grid g, excluding that source, is "0" at time t1. Then, based on the diffusion rate of VOCs gas i obtained experimentally under these conditions, and a predetermined allowable diffusion time (the difference between data acquisition points t2 and t1 within the period), the secondary height can be determined as the product of this diffusion rate and the allowable diffusion time. It should be noted that when setting the secondary height, it is assumed that the concentration of VOCs gas i generated by the VOCs source is the average concentration of type i VOCs gas generated by that source each time within a specified historical time period.

[0093] However, if there are too many detection sites at the secondary height, the amount of data for early warning analysis becomes larger, and the early warning process becomes more complex. Furthermore, directly using VOCs concentration data detected at the secondary height as the basis for early warning analysis results in overly sensitive warnings, failing to meet the requirements for balancing concentration detection accuracy and early warning sensitivity in the specific scenario described in the background. To address this issue, this embodiment employs a gradient height setting method. Specifically, a VOCs concentration detection device at the primary height is further installed above the secondary height, and VOCs concentration is further detected at time t2 of each cycle using the detection device at the primary height. This considers the impact of the diffusion capabilities of different types of VOCs in a specific factory environment on the accuracy of VOCs concentration detection, providing an early warning lag time to meet the requirement of balancing VOCs concentration detection accuracy and early warning sensitivity in this specific scenario.

[0094] 3. This invention, by setting a gradient height to achieve delayed early warning, dynamically adjusts the first-level height and horizontal position of the first point in each grid g in each cycle. This helps ensure the accuracy of the VOCs concentration estimation results used as the basis for early warning. Furthermore, the horizontal position adjustment process also serves as an initial screening process for locating suspected VOCs sources causing excessive VOCs concentrations. Subsequently, in the tracing process, this initial screening result enables rapid and accurate location of suspected VOCs sources causing excessive VOCs concentrations.

[0095] The following section elaborates on the method for constructing a periodic concentration site fluctuation map:

[0096] Figure 2 An exemplary diagram illustrates a cycle for VOCs concentration data collection during a specified time period from 9:00 AM to 9:30 AM. Each cycle k within this specified time period has two VOCs concentration data collection points, t1 and t2. The detection sites for VOCs concentration data collection are set at a height including a single level. and Level 2 height To accurately pinpoint the VOCs source sites causing excessive VOC concentrations, the factory's floor plan is divided into sections as follows: Figure 3 The diagram shows several grids g. VOCs generating devices (VOCs sources) are placed in grids g. Grid g may not contain any VOCs generating devices, or it may contain several VOCs generating devices that produce at least one type of VOCs gas, such as... Figure 3As shown, site 11 in the seventh grid produces VOCs gas H, site 2 produces VOCs gas B, site 12 in the sixteenth grid produces VOCs gases B and H, and site 7 produces VOCs gas F. The installation height (secondary height) of the VOCs concentration detection device above each site b in each grid is shown. The concentration of VOCs generated at site b is related to the diffusion rate of the VOCs gas. Different types of VOCs typically have different diffusion rates. Therefore, VOCs concentration detection devices placed above different sites b that generate different types of VOCs usually have different placement heights. This placement height refers to the secondary height associated with the site generating the VOCs gas. It should be noted here that each VOC-generating site b is associated with a corresponding secondary height. This secondary height is related to the diffusion rate of VOCs gas generated at the corresponding site b. For example, if the diffusion rate of VOCs gas A at site 1 is s1 and the diffusion rate of VOCs gas B at site 2 is s2, then the secondary height corresponding to site 1 is h1, and the secondary height corresponding to site 2 is h2. The specific settings for h1 and h2 have been explained in detail above and will not be repeated here. To simplify the process of VOCs concentration estimation and source analysis and early warning, in this embodiment, the secondary height associated with each site b is fixed. However, in the specific scenario described in the background, Figure 3 Different sites b within different grids may generate different types of VOCs gases during different data acquisition cycles at different specified time periods. Since different sites within the plant typically have different VOCs gas concentration differences at different times, these different types of VOCs gases have different diffusion rates at different times. To ensure the accuracy of VOCs concentration detection at the secondary height, ideally, the secondary height associated with each site b should be adaptively adjusted according to different diffusion rates. However, adjusting the secondary height requires each VOCs concentration detection device at the secondary height to have a height adjustment function, which undoubtedly increases the construction cost of the VOCs source analysis and early warning system. Furthermore, secondary height adjustment requires adjustment time, which needs to be adapted to the data acquisition time points in the data acquisition cycle. However, since the adjustment amount for the secondary height of each site b is usually different, the adjustment time also varies, making it difficult to achieve uniform adaptation to the data acquisition time points in the data acquisition cycle. Considering the above, in this embodiment, the secondary height of each site b is set to a fixed height.

[0097] Periodic site concentration fluctuation graph as shown Figure 4 As shown, with Figure 2The time t2 of each period and each grid g shown are the x-axis and y-axis coordinates in the XY-axis coordinate system, respectively. Using the binding points as the plotting objects, the binding points are plotted in the XY-axis coordinate system to form a periodic concentration site floating map. The binding points plotted in the periodic concentration site floating map are obtained through the following steps:

[0098] L1, in such Figure 2 At time t1 of each k-cycle of the specified time period, the VOCs gas generating device in each grid g is obtained at a secondary height. corresponding site Concentration of each VOCs gas i collected at the site

[0099] L2, in each In the process, the gas concentrations with the highest concentration u are extracted to form a gas concentration set.

[0100] L3, judgment Does the concentration of each gas exceed its corresponding concentration threshold?

[0101] If so, then proceed to time t1 of period k+1 to process the grid g with first-order height. site The process of setting and adjusting the position is completed to obtain the site. At the first level of the k+1 cycle Then proceed to step L4, site Also updated to site It should be noted here that... This refers to the adjusted position of the corresponding site at time t1 in period k+1. Within each period k, sites with a first-level elevation position are adjusted only once. It should be noted that when k=1, the site is set above each grid g. Level 1 height The initial height is preferably the last first-level height adjustment made for the grid g in the last cycle of the previous specified time period of the current specified time period, or it is a specified first-level initial height set above the center point of the grid g.

[0102] If not, then maintain the site within period k+1. The setting position is the same as the setting position in the k-cycle;

[0103] L4, in such Figure 2 The point at time t2 of each period of the specified time period shown is the point at which the position adjustment is completed. The concentration of each VOCs gas i was collected at the site. and form sites -Grid g-Time t2 of period k+1-Collected concentrations The binding relationship is established, and then, using this binding relationship as the binding point, and with time t2 of each period and grid g as the x-axis and y-axis coordinates of the binding point in the XY-axis coordinate system, respectively, each binding point is plotted onto the XY-axis coordinate system to form a pattern as shown below. Figure 4 The diagram shows the periodic concentration site fluctuations. In step S1, based on this established binding relationship, the top 'a' points in terms of quantity can be quickly obtained. (Each binding point is associated with a site) The concentrations of each VOCs gas i collected at the corresponding first-level altitude.

[0104] The key to ensuring accurate VOCs source location in this invention lies in dynamically adjusting the primary height of the detection device above each grid g in each cycle. This adjustment of the primary height takes into account the diffusion rates of different types of VOCs from the secondary height, solving the technical problem of excessively high warning sensitivity due to neglecting VOCs diffusion capabilities, resulting in counterproductive warning effects. Furthermore, by setting separate primary and secondary heights for VOCs concentration detection for each grid, different types of VOCs exhibit different diffusion capabilities at varying concentration differences during VOCs source analysis. By dynamically adjusting the primary height of the detection device, a balance is struck between ensuring accuracy in VOCs source analysis and warning sensitivity.

[0105] In step L3 above, the position is dynamically adjusted at time t1 of period k+1. Location includes to The vertical height can be adjusted as follows:

[0106] The factory space is divided into several grids g. Each grid g has a longitudinal space from the ground to the roof. The first point corresponding to each binding point in the periodic concentration site floating map is set at the first level of the longitudinal space of the corresponding grid g.

[0107] At least one second site is also set in the vertical space of each grid g. Each second site in grid g is set at a secondary height above the corresponding VOCs source. The secondary height of each second site in the space of grid g is fixed, while the primary height of the primary site in the space of grid g is dynamically adjusted with the change of the VOCs detection cycle. The method for adjusting the primary height in cycle k+1 is: the height difference between each second site and the primary site in the vertical space of grid g. It is calculated using the following formula (1):

[0108]

[0109] In formula (1), m represents the number of m-th second sites with a second-level height set in grid g;

[0110] M represents the number of second sites set within grid g;

[0111] This represents the maximum rate at which VOCs gas diffuses from the m-th second site within grid g during period k;

[0112] Δt is the allowed diffusion time from the second site, and Δt is the time difference between time t2 and time t1 of data acquisition in each period k;

[0113] It is calculated using the following formula (2):

[0114]

[0115] In formula (2), This represents the rate at which VOCs gas of type i diffuses from the m-th second site within period k;

[0116] I represents the number of VOCs gas types diffusing from the m-th second site.

[0117] Specifically, in an experimental scenario with the same factory environment, at time t1 of period k, the same concentration of type i VOCs gas detected at the m-th second site in the same grid g is generated, and at this time, the concentration of type i VOCs gas at other spatial sites in grid g, except for the second site m, is "0", which is the experimental diffusion rate of type i VOCs gas from the second site m in grid g.

[0118] In step L3 above, the position is dynamically adjusted at time t1 of period k+1. The location also includes the position of The horizontal position is adjusted, and the specific adjustment method includes the following steps:

[0119] A1, obtain the first-level height on grid g at time t2 within a specified period of k periods. The concentrations of the top VOCs gases detected at u

[0120] A2, obtain the secondary height of each grid on grid g at time t1 within the specified period k+1. (The secondary height is fixed, therefore the secondary height within period k+1 is also the same.) Instead The concentrations of each VOC gas i detected And extract the concentration of VOCs gas of the same type as the top u obtained in step A1. Each VOCs-generating site b in grid g has a corresponding secondary height.

[0121] A3. For each type of VOCs gas u obtained in steps A1-A2, calculate the concentration difference.

[0122] A4, according to Calculate the diffusion factor u for each type of VOCs gas;

[0123] A5, based on the calculated diffusion factor within a preset time range after time t1 in period k+1 (less than the time difference between time t2 and time t1 in period k+1), the site is... The horizontal position is adjusted to the site.

[0124] In A4, the diffusion factor is calculated using the following formula (1):

[0125]

[0126] In formula (1), This represents the diffusion factor of VOCs gas of type u generated in grid g at time t1 in period k+1;

[0127] U indicates to proceed The number of VOCs gas types calculated.

[0128] In step A5, the site The horizontal position is adjusted to the site. The method is as follows:

[0129] A51, Identify the concentrations obtained in step A2 that are involved in the concentration difference calculation in step A3. The corresponding VOCs gas generation site O u As a site The basis for adjusting the horizontal position (which can be based on a pre-constructed site). - Identification of the binding relationship between the VOCs gas generating device (site b) and the grid g containing the VOCs generating device;

[0130] A52, Horizontal Movement Site And calculate the moved site O s With each O u distance

[0131] A53, calculate each distance Distance ratio

[0132] A54, Determine the proportion of each distance. Does it satisfy the corresponding diffusion factor? proportional relationship (if) fall into The corresponding factor value range is then determined. and (Satisfying the proportional relationship)

[0133] If so, then site O S As the site after horizontal position adjustment And terminate the position adjustment process;

[0134] If not, proceed to step A55;

[0135] A55, determine whether the preset allowable time for position movement has been reached.

[0136] If so, then via site O S Move back to Location (abandoning position adjustment);

[0137] If not, return to step A52 and continue moving the position horizontally.

[0138] For example, in the method of adjusting the horizontal position of the first-level height, suppose the generation point O in the grid g identified in step A51 is... u include Figure 5 The sites 1, 2, and 3 shown have secondary heights h1, h2, and h3, respectively. VOCs concentration detection devices P1, P2, and P3 are installed at these secondary heights h1, h2, and h3, respectively. Assume that P1 detects VOCs gas type A, P2 detects B, and P3 detects C, and the diffusion factors of VOCs gases A, B, and C are c1, c2, and c3, respectively. The primary height associated with grid g is, for example, [missing information]. Figure 5 H in g At time t1 of period k, the VOCs concentration detection device is set at a height of H. g site P g Location. Horizontal movement point P g arrive Figure 5 O in s At this point, the result calculated They are respectively Figure 5L1, L2, and L3 are shown in the figure. Then, according to the above formula (2), each can be calculated. Finally, when each is determined All fall into the corresponding diffusion factor The corresponding factor value range is then used to determine and The proportional relationship is satisfied, and the position O where the body stays at this time is... s As the site after horizontal position adjustment

[0139] It should be noted that the vertical height of the first point should be adjusted first, followed by the horizontal position. Additionally, it should be noted that... Figure 5 As shown, at P with a first-order height g If the highest concentration of VOCs gases, such as A, B, and C, is detected at point U, then at point P1, which has a secondary altitude, only two VOCs gases, A and B, may be detected. In this case, when calculating the diffusion factor c1, the highest concentration of VOCs gas detected at point P1 is chosen as the basis for calculating the diffusion factor c1.

[0140] When the concentration of VOCs gas of type i exceeds the standard using the above method, the tracing process for the VOCs source causing the concentration exceedance specifically includes the following steps:

[0141] B1, based on the calculation And are non-zero values The corresponding site Level 1 height Obtain the height of each of the first-level heights Associated secondary heights

[0142] B2, obtain the secondary altitudes obtained in step B1 at time t1 of each period k in the specified time period. The VOCs gas types collected at the site are determined, and it is determined whether type i is included.

[0143] If so, then corresponding sites Add to the list of locations to be flagged for alarm purposes;

[0144] If not, then not The corresponding site Add to the list of locations to be flagged for alarm;

[0145] B3, based on pre-constructed sites -The binding relationship between the VOCs gas generating device and the grid g where the VOCs generating device is located is matched to identify the VOCs generating device bound to each location in the list of potential alarm locations and the grid g corresponding to the matched VOCs generating device, and an alarm is triggered.

[0146] In summary, this invention provides a novel method for estimating VOC concentrations. By dynamically setting the step height in each data acquisition cycle, the method scientifically sets the VOC concentration detection frequency. Based on the accurate VOC concentration detected at the secondary height, and considering the impact of different diffusion rates of different types of VOCs at each secondary height in each detection cycle on the accuracy of VOC concentration detection at the primary height, the method constructs a periodic concentration site fluctuation map to estimate VOC concentrations. The estimation results are then used to determine whether the VOC concentration exceeds the standard. This method strikes a balance between the accuracy of VOC concentration estimation and the sensitivity of early warning, meeting the alarm sensitivity requirements for this specific scenario described in the background section.

[0147] It should be stated that the above-described specific embodiments are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that various modifications, equivalent substitutions, and variations can be made to the present invention. However, such variations, as long as they do not depart from the spirit of the present invention, should be within the scope of protection of the present invention. Furthermore, some terminology used in this specification and claims is not limiting, but merely for ease of description.

Claims

1. A method for estimating the concentration of volatile organic compounds under alarm sensitivity equilibrium, characterized in that the steps include... include: S1, from dynamically updated data related to each type of VOC gas within a specified time period. Extract the top 'a' points from the corresponding periodic concentration site fluctuation plots. ; S2, obtain each within the specified time period Periodic At each of the aforementioned sites VOCs gases collected at the site concentration ; S3, calculate each of the VOCs gases Average gas concentration during the specified time period As for the type The concentration estimation results of VOCs gas, This indicates the number of items 'a' that rank in the top 'a'. S4, determine whether at least one type is The estimated concentration of VOCs gas exceeded the standard. If so, then proceed to trigger Traceability process for VOCs sources with excessive concentrations; If not, the traceability process will not be initiated. The periodic concentration site floating map is constructed using the following method steps: L1, the factory space is divided into several grids. During each specified time period Periodic At any given time, obtain each grid. Each VOCs gas generating device in the process has a secondary height The corresponding site VOCs gases collected at the site concentration ; L2, in each Among them, the concentrations ranked first were extracted. The gas concentration forms a gas concentration set. ; L3, judgment Does the concentration of each gas exceed its corresponding concentration threshold? If so, then proceed to... Periodic Constantly on the grid The middle has a first-level height site The process of setting and adjusting the position is completed to obtain the site. exist The first level of the cycle Then proceed to step L4, site Also updated to site ; If not, then in Sites maintained during the cycle The setting location and in The period settings are in the same location; L4, in each cycle of a specified time period At any given moment, from the point where the position adjustment is completed. Collect various VOCs gases at the site concentration and form sites -Grid -cycle of Time - Concentrations collected The binding relationship is then established, and this binding relationship is used as the binding point, with each period's... Time and Grid The x and y coordinates of the binding points are respectively the x and y coordinates of the binding points in the X and Y coordinate system. The binding points are plotted on the X and Y coordinate system to form a periodic concentration site floating map.

2. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 1, characterized in that, The factory space is divided into several grids. Each of the grids Having a longitudinal space from the ground to the roof within the factory building, the first point corresponding to each binding point plotted in the periodic concentration site floating map is respectively set in a corresponding grid. At the first level of vertical space.

3. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 2, characterized in that, In each of the grids At least one second site is also provided within the longitudinal space of the grid. Each of the second sites within the grid is positioned at a secondary height above the corresponding VOCs generating source. The secondary height of each of the second points within the space is fixed, while that of the grid is set in the space. The first-order height of the first site within the space is dynamically adjusted according to the VOCs detection cycle. The method for periodically adjusting the height at level one is as follows: the grid The height difference between each of the second points and the first point in the longitudinal space It is calculated using the following formula (1): In formula (1), Indicates that it is set in the grid The second level of the inner height The number of second sites; Indicated in the grid The number of the second site set inside; Indicates in VOCs gas from the grid during the cycle The first The average rate of diffusion at each second site; The allowable diffusion time for diffusion from the second site. In each cycle Data collection in China Time and The time difference between moments; It is calculated using the following formula (2): In formula (2), Indicates in The type within the period is VOCs gas from the first The rate of diffusion at the second site; Indicates from the first The number of types of VOCs gases diffused at the second site.

4. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 3, characterized in that, For example: In an experimental scenario with the same factory environment, within the same grid... The first in Generated at the second site The type detected at this site at time t1 of the period The same concentration of VOCs gas, and at this time the grid Except for the second site Other spatial sites When the concentration of all types of VOCs gases is "0", Types of VOCs gases from the grid The second site The diffusion rate was measured in the diffusion experiment.

5. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 1, characterized in that, In step L3, Periodic The site is dynamically adjusted in real time. Location includes to The horizontal position is adjusted, and the specific adjustment method includes the following steps: A1, obtain the data during the specified time period. Within the period At any time in the grid The next level The concentration detected at the top Concentration of each VOC gas ; A2, obtain the data during the specified time period. Within the period At that time, in the grid Each secondary height VOCs gases detected at the location concentration And extract the top-ranked results obtained in step A1. VOCs gas concentration of the same type The grid Each site in the matrix that produces VOCs gas Having corresponding secondary heights ; A3, for each type of VOC gas obtained in steps A1-A2 Calculate the concentration difference ; A4, according to Calculate each type of VOC gas The diffusion factor; A5, based on each of the calculated diffusion factors in Within the period Within a preset time period after the time, the site will be The horizontal position is adjusted to the site. .

6. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 5, characterized in that, In step A4, each type of VOCs gas The diffusion factor is calculated using the following formula (3): In formula (3), Indicates generation in the grid The type in VOCs gas in Periodic The diffusion factor at time; Indicates to proceed The number of VOCs gas types calculated.

7. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 6, characterized in that, site The horizontal position is adjusted to the site. The method includes the following steps: A51, Identify the concentrations obtained in step A2 that are involved in the concentration difference calculation in step A3. Corresponding VOCs gas generation sites As a site The basis for adjusting the horizontal position; A52, Horizontally move the location And calculate the moved site With each distance ; A53, calculate each of the distances. Distance ratio ; A54, determine each of the aforementioned distance ratios Does it satisfy the corresponding diffusion factor? proportional relationship, If so, then the site The site after horizontal position adjustment And terminate the position adjustment process; If not, proceed to step A55; A55, determine whether the preset allowable time for position movement has been reached. If so, then via the stated site Move back to Location; If not, return to step A52 and continue moving the site horizontally. ; In step A53, the distance ratio is calculated using the following formula (4). :

8. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to claim 7, characterized in that, The distance ratio mentioned in step A54 Satisfying the corresponding diffusion factor The proportional relationship is: judge Has it fallen into The corresponding factor value range, If so, then determine and Satisfy the proportional relationship; If not, then determine and The proportional relationship is not satisfied.

9. The method for estimating volatile organic compound concentration under alarm sensitivity equilibrium according to any one of claims 1-8, characterized in that, The traceability process in step S4 includes the following steps: B1, based on the calculation And are non-zero values The corresponding site Level 1 height Obtain the height of each of the first-level heights. Associated secondary heights ; B2, acquire each cycle of the detection device during the specified time period. of The secondary heights obtained at each time step B1 The type of VOCs gas collected at the site is determined, and it is determined whether it includes [the following]. type, If so, then corresponding sites Add to the list of locations to be flagged for alarm purposes; If not, then not The corresponding site Add to the list of locations to be flagged for alarm; B3, based on pre-constructed sites -VOCs gas generating equipment-Grid where VOCs generating equipment is located The binding relationship is used to match the VOCs generating device bound to each site in the list of potential alarm sites and the grid corresponding to the matched VOCs generating device. And issue a notification and alarm.

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