Method for detecting ethylene oxide and acetonitrile in stationary source waste gas

Abstract

The invention discloses a method for detecting ethylene oxide and acetonitrile in stationary source waste gas, which comprises the following steps: collecting the stationary source waste gas according to a waste gas sampling device, and researching the movement direction of the stationary source waste gas to obtain movement characteristics; carrying out ethylene oxide and acetonitrile detection on the stationary source waste gas by adopting a gas chromatographic method according to the motion characteristics to obtain first detection data; carrying out ethylene oxide detection on the stationary source waste gas by adopting an electrochemical analysis method, and carrying out acetonitrile detection by adopting a liquid chromatography to obtain second detection data; and performing data fusion on the first detection data and the second detection data to obtain a comprehensive quantity, and outputting the comprehensive quantity as a detection result. The method not only can improve the detection precision of the ethylene oxide and the acetonitrile in the stationary source waste gas, but also has better interpretability, and can be directly applied to a detection system of the ethylene oxide and the acetonitrile in the stationary source waste gas.

Description

Technical Field

[0001] The invention relates to the field of detection, and in particular to a method for detecting ethylene oxide and acetonitrile in fixed source exhaust gas. Background Art

[0002] The molecular formula of ethylene oxide is C2H4O, with a molecular weight of 44.05. It is a polar compound, miscible with water, a colorless transparent liquid at low temperatures, and a colorless gas with a pungent odor at room temperature. The gas has a high vapor pressure and strong penetrating power. It is a heterocyclic compound and an important petrochemical product. The molecular formula of acetonitrile is C2H3N, with a molecular weight of 41.05. It is a polar compound, miscible with water, and a colorless transparent liquid at room temperature. It has excellent solvent properties and can dissolve a variety of organic, inorganic and gaseous substances. Both ethylene oxide and acetonitrile are volatile organic compounds (VOCs), which bring certain harm to the environment and human health. Ethylene oxide, in particular, also has certain carcinogenic effects. Therefore, limit requirements for ethylene oxide and acetonitrile are proposed in relevant national and local standards. Ethylene oxide and acetonitrile mainly come from industrial waste gas. The national standard "Petrochemical Industry Pollutant Emission Standard (GB 31571-2015)", Beijing "Refining and Petrochemical Industry Air Pollutant Emission Standard (DB 11 / 447-2015)", Beijing "Air Pollutant Comprehensive Emission Standard (DB 11 / 501-2017)" and Shanghai "Air Pollutant Comprehensive Emission Standard (DB 31 / 933-2015)" have clear limit requirements for ethylene oxide and acetonitrile, but do not clearly specify the detection method standard. Therefore, the research and development of ethylene oxide and acetonitrile detection methods in exhaust gas from pollution sources is of great significance to environmental management. Summary of the invention

[0003] The object of the present invention is to provide a method for detecting ethylene oxide and acetonitrile in waste gas from a fixed source.

[0004] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0005] The present invention comprises the following steps:

[0006] Collecting fixed source exhaust gas according to the exhaust gas sampling device, and studying the movement direction of the fixed source exhaust gas to obtain movement characteristics;

[0007] According to the motion characteristics, gas chromatography is used to detect ethylene oxide and acetonitrile in the fixed source exhaust gas to obtain first detection data;

[0008] The fixed source exhaust gas is subjected to ethylene oxide detection by electrochemical analysis, and acetonitrile detection by liquid chromatography to obtain second detection data;

[0009] The first detection data and the second detection data are fused to obtain a comprehensive quantity, and the comprehensive quantity is output as a detection result.

[0010] Furthermore, a method for studying the movement direction of the fixed source exhaust gas to obtain movement characteristics includes:

[0011] Count the positions of ethylene oxide and acetonitrile under different flow conditions, and obtain the movement trajectories of ethylene oxide and acetonitrile according to the positions of ethylene oxide and acetonitrile;

[0012] Taking ethylene oxide and acetonitrile as particles, calculate the shear gradient lift and induced force of the particles:

[0013]

[0014]

[0015] The lift coefficient β L , the density of the i-th particle in the fixed source exhaust is The maximum moving speed of the i-th particle of the fixed source exhaust is v i,max , the diameter of the i-th particle is d i , the shear gradient lift of the ith particle close to the wall is U i,w , the induced force of the i-th particle away from the wall is U i,c , the height of the container is R;

[0016] According to the changes of shear gradient lift force near the wall and induced force far from the wall during particle movement, the particle deviation direction is captured;

[0017] Calculate the Reynolds number of a particle:

[0018]

[0019] The Reynolds number of the ith particle is The average velocity of the i-th particle is The width of the container is K, and the viscosity of the i-th particle is

[0020] When the Reynolds number of the particle is greater than 240, the particle moves in the extension direction of the container; when the Reynolds number of the particle is greater than 160 and less than 240, the particle moves in the opposite direction of the extension of the container; when the Reynolds number of the particle is greater than 80 and less than 160, the particle performs eddy motion; when the Reynolds number of the particle is less than 80, the particle cannot move.

[0021] Furthermore, the method of obtaining first detection data by detecting ethylene oxide and acetonitrile in the fixed source exhaust gas using gas chromatography according to the motion characteristics includes:

[0022] Determine the sampling location and sampling point of the exhaust gas emissions from fixed pollution sources according to the movement characteristics, and connect the exhaust gas sampling device according to certain technical requirements;

[0023] When sampling, the exhaust gas sampling device uses 20-50 mL of pure water as the absorption liquid, which is placed in the absorption bottle, and then the power is turned on. The collected solution is tested by gas chromatography using a hydrogen flame ionization detector;

[0024] Prepare standard solutions of ethylene oxide and acetonitrile with different concentrations for gas chromatography analysis, and establish a working curve graph based on the gas chromatography analysis data, with the concentration of the standard series as the abscissa and the corresponding chromatographic peak area as the ordinate;

[0025] Calculate the correlation coefficient between ethylene oxide and acetonitrile, determine their correlation based on the correlation coefficient, and perform quantitative calculation when the correlation coefficient is greater than 0.999;

[0026] According to the peak area of ​​ethylene oxide, calculate the concentration of ethylene oxide:

[0027] y1=427.99x1+1146.9

[0028] The concentration of ethylene oxide is x1, and the peak area of ​​ethylene oxide is y1.

[0029] According to the peak area of ​​acetonitrile, calculate the concentration of acetonitrile:

[0030] y2=164.54x2+24.599

[0031] The concentration of the target compound acetonitrile is x2, and the peak area of ​​acetonitrile is y2;

[0032] Calculation method Minimum detection limit:

[0033] MDL=t (n-1,0.99) ×S

[0034] Where MDL is the method detection limit, n is the number of parallel measurements of the sample, t is the degree of freedom, n-1 is the t distribution value at a confidence level of 99%, and the standard deviation of n parallel measurements is S;

[0035] According to the optimized gas chromatography conditions and the best purge and trap conditions, the low-concentration samples were measured seven times continuously, the standard deviation was calculated, and the minimum detection limit of ethylene oxide was obtained according to the method minimum detection limit formula;

[0036] According to the optimized gas chromatography conditions and the optimal purge and trap conditions, the low-concentration samples were measured continuously for 7 times to obtain the measured values. After calculating the standard deviation S, t(6,0.99) was found to be 3.143 from the literature. The minimum detection limit of acetonitrile was calculated according to the minimum detection limit of the method.

[0037] Furthermore, the method for detecting ethylene oxide in the fixed source exhaust gas by electrochemical analysis includes:

[0038] According to the motion characteristics, a gas sampling pump is installed to collect samples of fixed source exhaust gas, the samples are pretreated, the pretreated samples are introduced into the oxygen sensor, and the electrical signal of the oxygen sensor is recorded;

[0039] The electrical signal includes a change in current or voltage. The electrical signal is converted into a concentration value of ethylene oxide according to the response of the sensor and a known calibration curve, and the concentration value of ethylene oxide is output.

[0040] Further, the method for acetonitrile detection using liquid chromatography comprises:

[0041] Collecting a sample of the waste gas from a fixed source, collecting organic compounds in the waste gas through an adsorbent, eluting with a solvent, collecting the eluent to pretreat the sample, and using a mixture of methanol and water as the mobile phase;

[0042] The treated sample is injected into a C18 reverse phase chromatographic column through an automatic sample injector, the sample passes through the chromatographic column along with the mobile phase, and acetonitrile is separated through the interaction with the stationary phase and the mobile phase;

[0043] The chromatographic peak of acetonitrile is recorded using a differential detector, and the concentration value of acetonitrile is output based on the retention time and area of ​​the chromatographic peak by comparing it with the standard.

[0044] Furthermore, the method of performing data fusion on the first detection data and the second detection data to obtain comprehensive detection includes:

[0045] The first detection data and the second detection data are input into the data fusion model, and the total mean square error of the detection data is calculated:

[0046]

[0047] The total mean square error is The weighting factor of the kth data is ρ k , the kth data is u k , the number of detection data is N, and the expected function is σ[·];

[0048] Construct an auxiliary function, the expression is:

[0049]

[0050] The Lagrange multiplier is μ, and the variance of the kth data is Calculate the partial derivative of the auxiliary function with respect to the weighting factor and set the partial derivative to 0 to obtain the extreme value and Lagrange multiplier expression, which is:

[0051]

[0052]

[0053] The maximum value of the weighting factor is ρ max , the weighted coefficient calculation formula is obtained according to the total mean square error, extreme value and Lagrange multiplier, and the expression is:

[0054]

[0055] The weight coefficient of the kth data is Performing mean standardization on the first detection data and the second detection data respectively;

[0056] Extract the feature vectors of the first detection data and the second detection data after mean normalization, and the expression is:

[0057]

[0058] The eigenvector of the kth data at the yth attribute is χ(u ky ), the average value of the data at the yth attribute is The kth data at the yth attribute is u ky , data u ky The status is u ky (s), the number of states is M;

[0059] Construct a feature vector set based on the feature vector, and obtain the optimal hyperplane of the data based on the weighted coefficient feature vector set. The expression is:

[0060]

[0061] The optimal hyperplane is The bias is b, and the ath weighting coefficient is The ath hyperplane is The kernel function is Q(·), and the ath eigenvector set is Z a , the eigenvector set is Z;

[0062] Establish a data fusion model, the expression is:

[0063]

[0064] The data fusion model is The generalization parameter is φ, and the optimal solution for the a-th data is h a , the optimal solution for the jth data is h j , the optimal solution mean of the a-th data is The optimal solution for the jth data is The type of fused data is P;

[0065] The decision function of the data is established according to the optimal solution of the data. The expression is:

[0066]

[0067] The decision function is The data mean set of fused data type P is The optimal solution for the fused data type P is h P ;

[0068] The data fusion model is solved according to the decision function and the fusion result is output.

[0069] In a second aspect, an embodiment of the present application further provides an electronic device, including:

[0070] A processor; and a memory arranged to store computer executable instructions, which when executed cause the processor to perform the method steps described in the first aspect.

[0071] In a third aspect, an embodiment of the present application further provides a computer-readable storage medium, which stores one or more programs. When the one or more programs are executed by an electronic device including multiple applications, the electronic device executes the method steps described in the first aspect.

[0072] The beneficial effects of the present invention are:

[0073] The present invention is a method for detecting ethylene oxide and acetonitrile in fixed source exhaust gas. Compared with the prior art, the present invention has the following technical effects:

[0074] The present invention can improve the accuracy of detecting ethylene oxide and acetonitrile in waste gas from fixed sources by obtaining motion characteristics, acquiring first detection data, acquiring second detection data, data fusion and outputting result steps, thereby improving the accuracy of detecting ethylene oxide and acetonitrile in waste gas from fixed sources, optimizing the detection of ethylene oxide and acetonitrile in waste gas from fixed sources, greatly saving resources and improving work efficiency, realizing automatic detection of ethylene oxide and acetonitrile in waste gas from fixed sources, and performing detection correction on the detection of ethylene oxide and acetonitrile in waste gas from multiple fixed sources in real time, which is of great significance for the detection of ethylene oxide and acetonitrile in waste gas from multiple fixed sources, and can adapt to the detection of ethylene oxide and acetonitrile in waste gas from fixed sources of different standards and the detection requirements of ethylene oxide and acetonitrile in waste gas from different fixed sources, and has certain universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 This is a flow chart of the steps of a method for detecting ethylene oxide and acetonitrile in fixed source exhaust gas according to the present invention;

[0076] Figure 2 It is a schematic diagram of the structure of an electronic device in an embodiment of this specification. DETAILED DESCRIPTION

[0077] The present invention is further described below by means of specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0078] The present invention provides a method for detecting ethylene oxide and acetonitrile in fixed source exhaust gas, comprising the following steps:

[0079] like Figure 1 As shown, in this embodiment, the following steps are included:

[0080] Collecting fixed source exhaust gas according to the exhaust gas sampling device, and studying the movement direction of the fixed source exhaust gas to obtain movement characteristics;

[0081] According to the motion characteristics, gas chromatography is used to detect ethylene oxide and acetonitrile in the fixed source exhaust gas to obtain first detection data;

[0082] The fixed source exhaust gas is subjected to ethylene oxide detection by electrochemical analysis, and acetonitrile detection by liquid chromatography to obtain second detection data;

[0083] The first detection data and the second detection data are fused to obtain a comprehensive quantity, and the comprehensive quantity is output as a detection result.

[0084] In this embodiment, the method of studying the movement direction of the fixed source exhaust gas to obtain the movement characteristics includes:

[0085] Count the positions of ethylene oxide and acetonitrile under different flow conditions, and obtain the movement trajectories of ethylene oxide and acetonitrile according to the positions of ethylene oxide and acetonitrile;

[0086] Taking ethylene oxide and acetonitrile as particles, calculate the shear gradient lift and induced force of the particles:

[0087]

[0088]

[0089] The lift coefficient β L , the density of the i-th particle in the fixed source exhaust is The maximum moving speed of the i-th particle of the fixed source exhaust is v i,max , the diameter of the i-th particle is d i , the shear gradient lift of the ith particle close to the wall is U i,w , the induced force of the i-th particle away from the wall is U i,c , the height of the container is R;

[0090] According to the changes of shear gradient lift force near the wall and induced force far from the wall during particle movement, the particle deviation direction is captured;

[0091] Calculate the Reynolds number of a particle:

[0092]

[0093] The Reynolds number of the ith particle is The average velocity of the i-th particle is The width of the container is K, and the viscosity of the i-th particle is

[0094] When the Reynolds number of the particle is greater than 240, the particle moves in the extension direction of the container; when the Reynolds number of the particle is greater than 160 and less than 240, the particle moves in the opposite direction of the extension of the container; when the Reynolds number of the particle is greater than 80 and less than 160, the particle performs eddy motion; when the Reynolds number of the particle is less than 80, the particle cannot move.

[0095] In this embodiment, the method of detecting ethylene oxide and acetonitrile in the fixed source exhaust gas by gas chromatography according to the motion characteristics to obtain first detection data includes:

[0096] Determine the sampling location and sampling point of the exhaust gas emissions from fixed pollution sources according to the movement characteristics, and connect the exhaust gas sampling device according to certain technical requirements;

[0097] When sampling, the exhaust gas sampling device uses 20-50 mL of pure water as the absorption liquid, which is placed in the absorption bottle, and then the power is turned on. The collected solution is tested by gas chromatography using a hydrogen flame ionization detector;

[0098] Prepare standard solutions of ethylene oxide and acetonitrile with different concentrations for gas chromatography analysis, and establish a working curve graph based on the gas chromatography analysis data, with the concentration of the standard series as the abscissa and the corresponding chromatographic peak area as the ordinate;

[0099] Calculate the correlation coefficient between ethylene oxide and acetonitrile, determine their correlation based on the correlation coefficient, and perform quantitative calculation when the correlation coefficient is greater than 0.999;

[0100] According to the peak area of ​​ethylene oxide, calculate the concentration of ethylene oxide:

[0101] y1=427.99x1+1146.9

[0102] The concentration of ethylene oxide is x1, and the peak area of ​​ethylene oxide is y1.

[0103] According to the peak area of ​​acetonitrile, calculate the concentration of acetonitrile:

[0104] y2=164.54x2+24.599

[0105] The concentration of the target compound acetonitrile is x2, and the peak area of ​​acetonitrile is y2.

[0106] Calculation method Minimum detection limit:

[0107] MDL=t (n-1,0.99) ×S

[0108] Where MDL is the method detection limit, n is the number of parallel measurements of the sample, t is the degree of freedom, n-1 is the t distribution value at a confidence level of 99%, and the standard deviation of n parallel measurements is S;

[0109] According to the optimized gas chromatography conditions and the best purge and trap conditions, the low-concentration samples were measured seven times continuously, the standard deviation was calculated, and the minimum detection limit of ethylene oxide was obtained according to the method minimum detection limit formula;

[0110] According to the optimized gas chromatography conditions and the best purge and trap conditions, the low-concentration samples were measured seven times continuously to obtain the measured values. After calculating the standard deviation S, the literature found that t(6,0.99) was 3.143. The minimum detection limit of acetonitrile was calculated according to the minimum detection limit of the method.

[0111] In the actual evaluation, a purge-and-trap device with a certain volume of purge tube, a polar capillary column, and a gas chromatograph with a hydrogen flame ionization detector were used;

[0112] The sampling flow rate of the power supply is 0.5-1L / min, the flue gas temperature is 120℃, and the sampling time is 10-30min. The collected solution is transported back to the laboratory at low temperature. The chromatographic column is 30m*0.32mm*0.25um. The standard solutions of ethylene oxide and acetonitrile with different concentrations are 5μg / L, 10μg / L, 30μg / L, 50μg / L, 100μg / L and 200μg / L respectively. The correlation coefficients of ethylene oxide and acetonitrile are both 0.9998. The unit of peak area is μA*min.

[0113] Minimum detection limit of ethylene oxide: 7 low-concentration samples were measured continuously, and the measured values ​​were 3.47, 3.71, 3.65, 3.25, 3.84, 3.36, and 3.46, respectively. The standard deviation S was calculated to be 0.21, and t(6,0.99) was found to be 3.143 from the literature. According to the minimum detection limit calculation formula of the method, the minimum detection limit of ethylene oxide was 0.65μg / L.

[0114] Minimum detection limit of acetonitrile: 7 low-concentration samples were measured continuously, and the measured values ​​were 5.34, 5.68, 5.49, 5.50, 5.51, 5.76, and 5.81, respectively. The standard deviation S was calculated to be 0.17. From the literature, t(6,0.99) was found to be 3.143. According to the minimum detection limit calculation formula of the method, the minimum detection limit of ethylene oxide was obtained to be 0.53 μg / L.

[0115] In this embodiment, the method of detecting ethylene oxide in the fixed source exhaust gas by electrochemical analysis includes:

[0116] According to the motion characteristics, a gas sampling pump is installed to collect samples of fixed source exhaust gas, the samples are pretreated, the pretreated samples are introduced into the oxygen sensor, and the electrical signal of the oxygen sensor is recorded;

[0117] The electrical signal includes a change in current or voltage. The electrical signal is converted into a concentration value of ethylene oxide according to the response of the sensor and a known calibration curve, and the concentration value of ethylene oxide is output.

[0118] In this embodiment, the method of using liquid chromatography to detect acetonitrile comprises:

[0119] Collecting a sample of the waste gas from a fixed source, collecting organic compounds in the waste gas through an adsorbent, eluting with a solvent, collecting the eluent to pretreat the sample, and using a mixture of ethanol and water as a mobile phase;

[0120] The treated sample is injected into a C18 reverse phase chromatographic column through an automatic sample injector, the sample passes through the chromatographic column along with the mobile phase, and acetonitrile is separated through the interaction with the stationary phase and the mobile phase;

[0121] The chromatographic peak of acetonitrile is recorded using a differential detector, and the concentration value of acetonitrile is output based on the retention time and area of ​​the chromatographic peak by comparing it with the standard.

[0122] In this embodiment, a method for performing data fusion on the first detection data and the second detection data to obtain comprehensive detection includes:

[0123] The first detection data and the second detection data are input into the data fusion model, and the total mean square error of the detection data is calculated:

[0124]

[0125] The total mean square error is The weighting factor of the kth data is ρ k , the kth data is u k , the number of detection data is N, and the expected function is σ[·];

[0126] Construct an auxiliary function, the expression is:

[0127]

[0128] The Lagrange multiplier is μ, and the variance of the kth data is Calculate the partial derivative of the auxiliary function with respect to the weighting factor and set the partial derivative to 0 to obtain the extreme value and Lagrange multiplier expression, which is:

[0129]

[0130]

[0131] The maximum value of the weighting factor is ρ max , the weighted coefficient calculation formula is obtained according to the total mean square error, extreme value and Lagrange multiplier, and the expression is:

[0132]

[0133] The weight coefficient of the kth data is Performing mean standardization on the first detection data and the second detection data respectively;

[0134] Extract the feature vectors of the first detection data and the second detection data after mean normalization, and the expression is:

[0135]

[0136] The eigenvector of the kth data at the yth attribute is χ(u ky ), the average value of the data at the yth attribute is The kth data at the yth attribute is u ky , data u ky The status is u ky (s), the number of states is M;

[0137] Construct a feature vector set based on the feature vector, and obtain the optimal hyperplane of the data based on the weighted coefficient feature vector set. The expression is:

[0138]

[0139] The optimal hyperplane is The bias is b, and the ath weighting coefficient is The ath hyperplane is The kernel function is Q(·), and the ath eigenvector set is Z a , the eigenvector set is Z;

[0140] Establish a data fusion model, the expression is:

[0141]

[0142] The data fusion model is The generalization parameter is φ, and the optimal solution for the a-th data is h a , the optimal solution for the jth data is h j , the optimal solution mean of the a-th data is The optimal solution for the jth data is The type of fused data is P;

[0143] The decision function of the data is established according to the optimal solution of the data. The expression is:

[0144]

[0145] The decision function is The data mean set of fused data type P is The optimal solution for the fused data type P is h P ;

[0146] The data fusion model is solved according to the decision function and the fusion result is output.

[0147] Figure 2 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application. Figure 2 At the hardware level, the electronic device includes a processor, and optionally also includes an internal bus, a network interface, and a memory. The memory may include a memory, such as a high-speed random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk storage. Of course, the electronic device may also include hardware required for other services.

[0148] The processor, network interface and memory can be interconnected through an internal bus, which can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 2 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0149] The memory is used to store the program. Specifically, the program may include a program code, and the program code includes a computer operation instruction. The memory may include a memory and a non-volatile memory, and provides instructions and data to the processor.

[0150] The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it, forming a detection device for ethylene oxide and acetonitrile in the exhaust gas from a fixed source at the logical level. The processor executes the program stored in the memory and is specifically used to execute any of the above-mentioned methods for detecting ethylene oxide and acetonitrile in the exhaust gas from a fixed source.

[0151] The above application Figure 1 The detection method of ethylene oxide and acetonitrile in a fixed source exhaust gas disclosed in the illustrated embodiment can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or instructions in the form of software. The above processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in conjunction with the embodiments of the present application can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in a decoding processor. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0152] The electronic device may also perform Figure 1 A method for detecting ethylene oxide and acetonitrile in waste gas from a stationary source is developed and implemented. Figure 1 The functions of the illustrated embodiment will not be described in detail in the embodiments of the present application.

[0153] An embodiment of the present application also proposes a computer-readable storage medium, which stores one or more programs, and the one or more programs include instructions. When the instructions are executed by an electronic device including multiple application programs, any one of the aforementioned methods for detecting ethylene oxide and acetonitrile in fixed source exhaust gas is executed.

[0154] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0155] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0156] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0157] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0158] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0159] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0160] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0161] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0162] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0163] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting ethylene oxide and acetonitrile in fixed source exhaust gas, characterized in that: The following steps are involved: Collecting fixed source exhaust gas according to the exhaust gas sampling device, and studying the movement direction of the fixed source exhaust gas to obtain movement characteristics; According to the motion characteristics, gas chromatography is used to detect ethylene oxide and acetonitrile in the fixed source exhaust gas to obtain first detection data; The fixed source exhaust gas is subjected to ethylene oxide detection by electrochemical analysis, and acetonitrile detection by liquid chromatography to obtain second detection data; The first detection data and the second detection data are fused to obtain a comprehensive quantity, and the comprehensive quantity is output as a detection result.

2. The method for detecting ethylene oxide and acetonitrile in a stationary source exhaust gas according to claim 1, characterized in that: The method of studying the movement direction of the fixed source exhaust gas to obtain the movement characteristics includes: Count the positions of ethylene oxide and acetonitrile under different flow conditions, and obtain the movement trajectories of ethylene oxide and acetonitrile according to the positions of ethylene oxide and acetonitrile; Taking ethylene oxide and acetonitrile as particles, calculate the shear gradient lift and induced force of the particles: The lift coefficient β L , the density of the i-th particle in the fixed source exhaust is The maximum moving speed of the i-th particle of the fixed source exhaust is v i,max , the diameter of the i-th particle is d i , the shear gradient lift of the ith particle close to the wall is U i,w , the induced force of the i-th particle away from the wall is U i,c , the height of the container is R; According to the changes of shear gradient lift force near the wall and induced force far from the wall during particle movement, the particle deviation direction is captured; Calculate the Reynolds number of a particle: The Reynolds number of the ith particle is The average velocity of the i-th particle is The width of the container is K, and the viscosity of the i-th particle is When the Reynolds number of the particle is greater than 240, the particle moves in the extension direction of the container; when the Reynolds number of the particle is greater than 160 and less than 240, the particle moves in the opposite direction of the extension of the container; when the Reynolds number of the particle is greater than 80 and less than 160, the particle performs eddy motion; when the Reynolds number of the particle is less than 80, the particle cannot move.

3. The method for detecting ethylene oxide and acetonitrile in a stationary source exhaust gas according to claim 1, characterized in that: The method of obtaining first detection data by detecting ethylene oxide and acetonitrile in the fixed source exhaust gas using gas chromatography according to the motion characteristics comprises: Determine the sampling location and sampling point of the exhaust gas emissions from fixed pollution sources according to the movement characteristics, and connect the exhaust gas sampling device according to certain technical requirements; When sampling, the exhaust gas sampling device uses 20-50 mL of pure water as the absorption liquid, which is placed in the absorption bottle, and then the power is turned on. The collected solution is tested by gas chromatography using a hydrogen flame ionization detector; Prepare standard solutions of ethylene oxide and acetonitrile with different concentrations for gas chromatography analysis, and establish a working curve graph based on the gas chromatography analysis data, with the concentration of the standard series as the abscissa and the corresponding chromatographic peak area as the ordinate; Calculate the correlation coefficient between ethylene oxide and acetonitrile, determine their correlation based on the correlation coefficient, and perform quantitative calculation when the correlation coefficient is greater than 0.999; According to the peak area of ​​ethylene oxide, calculate the concentration of ethylene oxide: y1=427.99x1+1146.9 The concentration of ethylene oxide is x1, and the peak area of ​​ethylene oxide is y1. According to the peak area of ​​acetonitrile, calculate the concentration of acetonitrile: y2=164.54x2+24.599 The concentration of the target compound acetonitrile is x2, and the peak area of ​​acetonitrile is y2; Calculation method Minimum detection limit: MDL=t (n-1,0.99) ×S Where MDL is the method detection limit, n is the number of parallel measurements of the sample, t is the degree of freedom, n-1 is the t distribution value at a confidence level of 99%, and the standard deviation of n parallel measurements is S; According to the optimized gas chromatography conditions and the best purge and trap conditions, the low-concentration samples were measured seven times continuously, the standard deviation was calculated, and the minimum detection limit of ethylene oxide was obtained according to the method minimum detection limit formula; According to the optimized gas chromatography conditions and the optimal purge and trap conditions, the low-concentration samples were measured continuously for 7 times to obtain the measured values. After calculating the standard deviation S, t(6,0.99) was found to be 3.143 from the literature. The minimum detection limit of acetonitrile was calculated according to the minimum detection limit of the method.

4. The method for detecting ethylene oxide and acetonitrile in a stationary source exhaust gas according to claim 1, characterized in that: The method for detecting ethylene oxide in the fixed source exhaust gas by electrochemical analysis comprises: According to the motion characteristics, a gas sampling pump is installed to collect samples of fixed source exhaust gas, the samples are pretreated, the pretreated samples are introduced into the oxygen sensor, and the electrical signal of the oxygen sensor is recorded; The electrical signal includes a change in current or voltage. The electrical signal is converted into a concentration value of ethylene oxide according to the response of the sensor and a known calibration curve, and the concentration value of ethylene oxide is output.

5. The method for detecting ethylene oxide and acetonitrile in a stationary source exhaust gas according to claim 1, characterized in that: The method for detecting acetonitrile by liquid chromatography comprises: Collecting a sample of the waste gas from a fixed source, collecting organic compounds in the waste gas through an adsorbent, eluting with a solvent, collecting the eluent to pretreat the sample, and using a mixture of methanol and water as the mobile phase; The treated sample is injected into a C18 reverse phase chromatographic column through an automatic sample injector, the sample passes through the chromatographic column along with the mobile phase, and acetonitrile is separated through the interaction with the stationary phase and the mobile phase; The chromatographic peak of acetonitrile is recorded using a differential detector, and the concentration value of acetonitrile is output based on the retention time and area of ​​the chromatographic peak by comparing it with the standard.

6. The method for detecting ethylene oxide and acetonitrile in a stationary source exhaust gas according to claim 1, characterized in that: The method for performing data fusion on the first detection data and the second detection data to obtain comprehensive detection includes: The first detection data and the second detection data are input into the data fusion model, and the total mean square error of the detection data is calculated: The total mean square error is The weighting factor of the kth data is ρ k , the kth data is u k , the number of detection data is N, and the expected function is σ[·]; Construct an auxiliary function, the expression is: The Lagrange multiplier is μ, and the variance of the kth data is Calculate the partial derivative of the auxiliary function with respect to the weighting factor and set the partial derivative to 0 to obtain the extreme value and Lagrange multiplier expression, which is: The maximum value of the weighting factor is ρ max , the weighted coefficient calculation formula is obtained according to the total mean square error, extreme value and Lagrange multiplier, and the expression is: The weight coefficient of the kth data is Performing mean standardization on the first detection data and the second detection data respectively; Extract the feature vectors of the first detection data and the second detection data after mean normalization, and the expression is: The eigenvector of the kth data at the yth attribute is χ(u ky ), the average value of the data at the yth attribute is The kth data at the yth attribute is u ky , data u ky The status is u ky (s), the number of states is M; Construct a feature vector set based on the feature vector, and obtain the optimal hyperplane of the data based on the weighted coefficient feature vector set. The expression is: The optimal hyperplane is The bias is b, and the ath weighting coefficient is The ath hyperplane is The kernel function is Q(·), and the ath eigenvector set is Z a , the eigenvector set is Z; Establish a data fusion model, the expression is: The data fusion model is The generalization parameter is φ, and the optimal solution for the a-th data is h a , the optimal solution for the jth data is h j , the optimal solution mean of the a-th data is The optimal solution for the jth data is The type of fused data is P; The decision function of the data is established according to the optimal solution of the data. The expression is: The decision function is The data mean set of fused data type P is The optimal solution for the fused data type P is h P ; The data fusion model is solved according to the decision function and the fusion result is output.

7. An electronic device comprising: processor; as well as A memory arranged to store computer executable instructions, wherein when the executable instructions are executed, the processor executes the method according to any one of claims 1 to 6.

8. A computer-readable storage medium storing one or more programs, which, when executed by an electronic device including a plurality of application programs, enables the electronic device to execute the method according to any one of claims 1 to 6.

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