A method for obtaining the leakage emission of volatile organic compounds from equipment and pipelines

Abstract

The present invention discloses a method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines, belonging to the technical field of volatile organic compound emission detection and quantitative calculation. It is a method that uses the enterprise production process design specification or sampling test to obtain the VOCs component information of the leaked material, combines the TOC leakage detection concentration of the leaking equipment or pipeline, and obtains the VOCs emission amount during the leakage time through theoretical calculation. This method utilizes the existing conditions of the enterprise and the implemented leakage detection technology methods to quickly and effectively obtain the VOCs leakage emission amount, which is more feasible than directly testing and calculating the VOCs emission amount using the bag method. The calculated result of the obtained VOCs emission amount can be connected with the VOCs emission management system, providing key technical support for the enterprise emission calculation and the scientific decision-making of the environmental management department.

Description

Technical Field

[0001] The present invention relates to the detection and quantitative calculation of volatile organic compound emissions, and particularly to a method for obtaining the leakage emissions of volatile organic compounds from equipment and pipelines, belonging to the technical field of the detection and quantitative calculation of volatile organic compound emissions. Background Art

[0002] Leakage of equipment and pipelines is one of the main sources of unorganized emissions of VOCs in industries such as petroleum refining, petrochemical, and synthetic resins.

[0003] Currently, the common calculation methods for the leakage emissions of organic compounds from equipment and pipelines in the prior art include the bag actual measurement method, the correlation equation method, the screening range method, and the emission coefficient method.

[0004] Among them, the bag actual measurement method has extremely high operation difficulty, and there is no standardized sampling method for reference;

[0005] The range screening method is applied to calculate the leakage emission rate of inaccessible flanges or connectors. The usage conditions need to meet that at least 50% of the accessible flanges or connectors are detected, and at least one net detection value is greater than or equal to 10,000 μmol / mol. Therefore, its usage limitations are large and it does not have the conditions for universal promotion and application;

[0006] For the emission coefficient method, the same emission coefficients are used for different enterprises or production devices, without considering the differences in construction levels between different enterprises and the differences in production processes between different production devices. Therefore, it cannot accurately reflect the true emission level of enterprises and has a large calculation error.

[0007] Therefore, the relatively feasible method for characterizing the leakage emissions of organic compounds from equipment and pipelines currently is the correlation equation method, which uses the leakage detection concentration and empirical formula to convert the leakage emission rate, and combines the leakage time to calculate the leakage emissions.

[0008] However, it should be noted that although the organic compound emissions obtained by relying on the correlation equation method in the prior art are the total organic carbon (TOC) emissions, the emissions of each VOCs species cannot be directly obtained, nor can the total VOCs emissions be directly obtained.

[0009] This is because the detection method for the leakage concentration of equipment and pipelines and the empirical formula for the emission rate issued in China both quote the technical documents issued by the US Environmental Protection Agency.

[0010] In the United States, the leakage concentration and leakage rate of organic compound leakage from equipment and pipelines are characterized by TOC. The TOC emissions obtained by directly quoting the US emission accounting system in China are inconsistent with the VOCs emissions calculated in China's VOCs emission management. Therefore, it is necessary to propose a set of equipment and pipeline VOCs leakage emission accounting methods that are connected with China's environmental management. Summary of the Invention

[0011] The main object of the present invention is to provide a method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines.

[0012] The object of the present invention can be achieved by adopting the following technical solutions:

[0013] A method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines, comprising the following steps:

[0014] Using a detection device to detect the leakage at the sealed leakage point of the equipment or pipeline to obtain the TOC leakage concentration C (ppm) of the leaking equipment or pipeline;

[0015] Obtaining the component type V of the leaking equipment or pipeline;

[0016] Obtaining the TOC leakage mass emission rate E TOC (kg / h) of the leaking equipment or pipeline through the leakage concentration C and the relevant equation method;

[0017] Obtaining the VOCs species composition of the organic material flowing in the leaking equipment or pipeline, and obtaining the volume percentage Xi (%) of the VOCs species i in the leaking organic material;

[0018] Obtaining the relative response factor RRF of the VOCs species i in the leaking organic material on a hydrogen flame ionization detector i ;

[0019] Obtaining the number of carbon atoms N i and the molar molecular mass M i (g / mol) in the molecular formula of the VOCs species i in the leaking organic material;

[0020] Using the volume percentage X i , the relative response factor RRF on a hydrogen flame ionization detector i and the number of carbon atoms N in the molecular formula i of the VOCs species i to calculate the proportion P of the number of carbon atoms responding on the hydrogen flame ionization detector of the VOCs species i; i ;

[0021] Using the TOC leakage mass emission rate E TOC , the proportion P of the number of carbon atoms responding on the hydrogen flame ionization detector of the VOCs species i in the leaking organic material i , the relative response factor RRF of the species i on the hydrogen flame ionization detector i , the number of carbon atoms N in the molecular formula of the VOCs species i i and the molar molecular mass M i to calculate and obtain the mass leakage emission rate E VOCi(kg / h), and the calculation formula is as follows:

[0022]

[0023] The total VOCs leakage mass emission rate E is obtained by summing up the leakage rates of each VOCs species i of the leaked material. VOC (kg / h), and the calculation formula is as follows:

[0024] E VOC = ∑E VOCi ;

[0025] The VOCs leakage mass emission rate E of the leaked organic material VOC and the leakage time T (h) are used to calculate the VOCs leakage emission G (kg) of the leaking equipment or pipeline. The calculation formula is as follows:

[0026] G = E VOC ×T.

[0027] Preferably, when detecting the TOC leakage concentration C (ppm), a portable detection device based on the principle of a calibrated flame ionization detector is used, and the detection probe should be as close as possible to the leakage location to detect and obtain the TOC leakage concentration C (ppm) of the leaking equipment or pipeline.

[0028] Preferably, the component type V of the equipment or pipeline is valve, pump, connector, flange, open valve or open pipeline, gas valve, liquid valve, light liquid pump.

[0029] Preferably, the TOC leakage mass emission rate E TOC (kg / h), and the calculation formula is as follows:

[0030]

[0031] where, E TOC，0 refers to the TOC leakage rate when the detected value of the TOC leakage concentration C is between 0 and 1 ppm;

[0032] E TOC，p refers to the TOC leakage rate when the detected value of the TOC leakage concentration C is greater than or equal to 50000 ppm;

[0033] E TOC，f refers to the TOC leakage rate when the detected value of the TOC leakage concentration C is between 1 and 50000 ppm.

[0034] Preferably, the VOCs species composition of the organic material flowing in the leaking equipment or pipeline is obtained through the material balance table in the enterprise production process design scheme or the sampling and monitoring method.

[0035] Preferably, the relative response factor RRF of the VOCs species i of the leaked organic material on the flame ionization detector is obtained by using the literature materials or theoretical calculations related to the response factor of the flame ionization detector, or by using the direct experimental method with specific VOCs species for testing. i 。

[0036] Preferably, in the process of selecting the relative response factor, the reference standard substance corresponding to the relative response factor should be matched, and the response factor obtained by using the same standard substance as that used for calibrating the TOC leakage concentration detection equipment of the leaking equipment or pipeline should be selected.

[0037] For the case where the reference standard substance corresponding to the relative response factor is different from the same standard substance used for calibrating the TOC leakage concentration detection equipment of the leaking equipment or pipeline, proportional conversion and correction can be performed through the response factors of different standard substances on the flame ionization detector.

[0038] 8. A method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines according to claim 1, characterized in that: calculating the proportion P of the number of carbon atoms responding to the VOCs species i on the flame ionization detector. i ,The calculation formula is as follows:

[0039] P1:P2:…:P i =X1·RRF1·N1:X2·RRF2·N2:…:X i ·RRF i ·N i ;

[0040] ∑ i P i =1。

[0041] Wherein, P i is the proportion of the number of carbon atoms responding to the VOCs species i of the leaked organic material on the flame ionization detector;

[0042] X i is the volume percentage of the VOCs species i of the leaked organic material;

[0043] RRF i is the relative response factor of the VOCs species i of the leaked organic material on the flame ionization detector;

[0044] N i is the number of carbon atoms N in the molecular formula of the VOCs species i of the leaked organic material i 。

[0045] The beneficial technical effects of the present invention:

[0046] A method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines provided by the present invention uses the enterprise production process design specification or sampling test to obtain the VOC component information of the leaked material, combines the TOC leakage detection concentration of the leaking equipment or pipeline, and obtains the VOCs emission amount during the leakage time through theoretical calculation. This method utilizes the existing conditions of the enterprise and the implemented leakage detection technology methods to quickly and effectively obtain the VOCs leakage emission amount, which is more feasible than directly testing and calculating the VOCs emission amount using the bag method. The calculated result of the obtained VOC emission amount can be connected with the VOCs emission management system, providing key technical support for the enterprise emission calculation and the scientific decision-making of the environmental management department. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 FIG. is a system diagram of a preferred embodiment of a method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] To make the technical solutions of the present invention clearer and more definite for those skilled in the art, the present invention will be further described in detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0049] Embodiment 1

[0050] As Figure 1 shown, a method for obtaining the leakage emission amount of volatile organic compounds from equipment and pipelines provided in this embodiment uses a portable detection device based on the principle of a calibrated hydrogen flame ionization detector to detect the leakage of the equipment or pipeline sealing leakage. The detection probe should be as close as possible to the leakage position to detect and obtain the TOC leakage concentration C (ppm) of the leaking equipment or pipeline;

[0051] Obtain the component type V of the leaking equipment or pipeline, such as valves, flanges, connectors, etc.;

[0052] Use the leakage concentration C and the relevant equation method to obtain the TOC leakage mass emission rate E TOC (kg / h), and the calculation formula is as follows:

[0053]

[0054] Table 1 Equipment and Pipeline TOC Leakage Emission Rate Formula

[0055]

[0056]

[0057] Obtain the VOCs species composition of the organic materials flowing in the leaking equipment or pipeline through the material balance table or sampling and monitoring method in the enterprise production process design plan, and obtain the volume percentage X of the leaking organic material VOCs species i i (%);

[0058] Obtain the relative response factor RRF of the leaking organic material VOCs species i on the flame ionization detector by using literature data, theoretical calculation or experimental method i .

[0059] In the process of selecting the relative response factor, the reference standard substance corresponding to the relative response factor should be matched and corrected, and the response factor obtained by using the same standard substance as that used in the TOC leakage concentration detection equipment of the leaking equipment or pipeline should be selected;

[0060] The number of carbon atoms Ni and molar molecular mass M in the molecular formula of the VOCs species i in the leaking organic material are obtained by theoretical calculation i (g / mol);

[0061] Using the volume percentage X of the leaking organic material VOCs species i i , the relative response factor RRF on the flame ionization detector i and the number of carbon atoms N in the molecular formula i Calculate the proportion P of the number of carbon atoms responding to the VOCs species i on the flame ionization detector i , and the calculation formula is as follows:

[0062] P1:P2:…:P i =X1·RRF1·N1:X2·RRF2·N2:…:X i ·RRF i ·N i

[0063] ∑ i P i =1

[0064] Using the TOC leakage mass emission rate E of the leaking equipment or pipeline TOC , the proportion P of the number of carbon atoms responding to the VOCs species i of the leaking organic material on the flame ionization detector i , the relative response factor RRF of the species i on the flame ionization detector i , the number of carbon atoms N in the molecular formula of the VOCs species i i and the molar molecular mass M i , calculate the mass leakage emission rate Ei of the VOCs species i VOCi (kg / h), and the calculation formula is as follows:

[0065]

[0066] The leakage rates of each VOC species i of the leaked material are summed to obtain the total VOC leakage mass emission rate E VOC (kg / h), and the calculation formula is as follows:

[0067] E VOC = ∑E VOCi .

[0068] Using the VOC leakage mass emission rate E of the leaked organic material VOC and the leakage time T (h), the VOC leakage emission G (kg) of the leaking equipment or pipeline is calculated, and the calculation formula is as follows:

[0069] G = E VOC × T.

[0070] Example 2

[0071] According to Figure 1 the flow chart shown, for a liquid organic material leakage valve of a certain petrochemical enterprise, the VOC leakage emission of it is obtained by using the method of the present invention, and the main steps are as follows:

[0072] Use a calibrated portable detection device based on the principle of a hydrogen flame ionization detector to detect the leakage at the seal leakage of the leakage valve. The detection probe should be as close as possible to the leakage position, and the detected TOC leakage concentration C of the leaking equipment or pipeline is 10,000 ppm;

[0073] Obtain the component type V of the valve as a liquid valve;

[0074] Use the leakage concentration C and the relevant equation method to obtain the TOC leakage mass emission rate E of the leaking equipment or pipeline TOC is 9.88E-03 kg / h, and the calculation formula is shown in Table 1.

[0075] P4. Through the material balance table in the enterprise production process design scheme or the sampling and monitoring method, obtain the VOC species composition of the organic material flowing in the leaking equipment or pipeline, and obtain the volume percentage Xi (%) of each VOC species i of the leaked organic material, as shown in Table 2;

[0076] Use literature data, theoretical calculations or experimental methods to obtain the relative response factor RRF of each VOC species i of the leaked organic material on the hydrogen flame ionization detector i .

[0077] In the process of selecting the relative response factor, the reference standard substance corresponding to the relative response factor should be matched and corrected, and the response factor obtained by using the same standard substance as that used in the TOC leakage concentration detection equipment of the leaking equipment or pipeline should be selected to obtain the response factor RRF of each VOC speciesi , as shown in Table 2;

[0078] The number of carbon atoms N in the molecular formula of VOCs species i in the leaked organic material is obtained through theoretical calculation i and the molar molecular mass M i (g / mol), as shown in Table 2;

[0079] Table 2 Volume percentages, relative response factors, molar masses, and the number of carbon atoms in the molecular formula of each VOCs species in the leaked material;

[0080]

[0081]

[0082] Using the volume percentage X of VOCs species i in the leaked organic material i , the relative response factor RRF on the flame ionization detector i and the number of carbon atoms N in the molecular formula i Calculate the proportion P of the number of carbon atoms in the response of VOCs species i on the flame ionization detector i , and the calculation formula is as follows:

[0083] P1:P2:…:P i =X1·RRF1·N1:X2·RRF2·N2:…:X i ·RRF i ·N i

[0084] ∑ i P i =1

[0085] The proportion P of the number of carbon atoms in the response of VOCs species i on the flame ionization detector i The calculation results are shown in Table 3;

[0086] Table 3 The proportion P of the number of carbon atoms in the response of VOCs species i on the flame ionization detector i Calculation results

[0087] VOCs species <![CDATA[Percentage P of the number of carbon atoms to which each substance responds i > 3-methylpentane 0.02％ n-hexane 0.21％ methylcyclopentane 0.12％ 2,4-dimethylpentane 0.03％ cyclohexane 0.11％ 2-methylhexane 0.29％ 2,3-dimethylpentane 0.11％ 3-methylhexane 0.32％ n-heptane 0.36％ methylcyclohexane 0.23％ toluene 0.77％ 3-methylheptane 0.43％ n-octane 2.96％ ethylbenzene 0.25％ m / p-xylene 0.51％ o-xylene 0.22％ n-nonane 1.88％ 1,2,4-trimethylbenzene 0.31％ decane 0.08％ n-undecane 0.27％ acetone 20.53％ isopropanol 56.34％ dichloromethane 11.71％ ethyl acetate 0.86％ trichloroethylene 0.13％ tetrachloroethylene 0.95％ Total 100.00％

[0088] Using the TOC leakage mass emission rate E of the leaking equipment or pipeline TOC , the proportion P of the number of carbon atoms in the response of VOCs species i in the leaked organic material on the flame ionization detector i , the relative response factor RRF of species i on the flame ionization detector i , the number of carbon atoms Ni and the molar molecular mass M in the molecular formula of VOCs species i i , calculate the mass leakage emission rate Ei of VOCs species iVOCi (kg / h), and the calculation formula is as follows:

[0089]

[0090] The mass leakage emission rate E of each VOC species VOCi The calculation results are shown in Table 4;

[0091] The leakage rate of each VOC species i of the leaked material is summed to obtain the total VOC leakage mass emission rate E VOC (kg / h), and the calculation formula is as follows:

[0092] E VOC = ∑E VOCi ;

[0093] The calculation results show that the VOC leakage mass emission rate E of this leaking valve VOC is 2.46E-02 kg / h.

[0094] The VOC leakage emission G (kg) of the leaking equipment or pipeline is calculated using the VOC leakage mass emission rate EVOC of the leaking organic material and the leakage time T (h), and the calculation formula is as follows:

[0095] G = E VOC × T;

[0096] In this example, assuming that the leakage time of this leaking valve is one year, the calculated VOC leakage emission of this valve is 215.63 kg.

[0097] Table 4 Proportion P of the number of carbon atoms in the response of VOC species i on the flame ionization detector i Calculation results

[0098]

[0099]

[0100] As mentioned above, it is only a further embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention, according to the technical solution and its concept of the present invention, makes equivalent substitutions or changes, all belong to the protection scope of the present invention.

Claims

1. A method for obtaining the leakage emission of volatile organic compounds from equipment and pipelines, comprising the following steps: Use detection equipment to detect leaks at the sealing leaks of equipment or pipelines to obtain the TOC leakage concentration C (ppm) of the leaking equipment or pipelines; Get the component type V of the leaking equipment or pipeline; The TOC leakage mass emission rate E of the leaking equipment or pipeline is obtained by using the leakage concentration C and the related equation method. TOC (kg / h); Obtain the VOCs species composition of the organic material circulating in the leaking equipment or pipeline, and obtain the volume percentage Xi (%) of the VOCs species i of the leaked organic material; Obtain the relative response factor (RRF) of VOCs species i of leaked organic materials on the hydrogen flame ionization detector i ; Get the number of carbon atoms N in the molecular formula of VOCs species i in the leaked organic material i and molar mass M i (g / mol); The volume percentage of VOCs species i in the leaked organic material is X i , relative response factor RRF on hydrogen flame ionization detector i and the number of carbon atoms N in the molecular formula i Calculate the proportion of carbon atoms P that respond to VOCs species i on the hydrogen flame ionization detector i ; Features: The TOC leakage mass emission rate E of the leaking equipment or pipeline is TOC , the proportion of carbon atoms P of VOCs species i in the leaked organic material that responds to the hydrogen flame ionization detector i , relative response factor RRF of species i on hydrogen flame ionization detector i 、Number of carbon atoms in the molecular formula of VOCs species i i and molar mass M i , calculate the mass leakage emission rate E of VOCs species i VOCi (kg / h), the calculation formula is as follows: The total VOCs leakage mass emission rate E is obtained by summing the leakage rates of each VOCs species i in the leaking material. VOC (kg / h), the calculation formula is as follows: AND VOC =∑E VOCi ; Leakage of organic materials VOCs leakage mass emission rate E VOC The VOCs leakage emission G (kg) of the leaking equipment or pipeline is calculated based on the leakage time T (h). The calculation formula is as follows: G=E VOC ×T.

2. The method for obtaining the leakage and emission of volatile organic compounds from equipment and pipelines according to claim 1, characterized in that: When conducting TOC leakage concentration C (ppm) detection, use a portable detection device based on the principle of calibrated hydrogen flame ionization detector. The detection probe should be as close to the leakage location as possible to detect and obtain the TOC leakage concentration C (ppm) of the leaking equipment or pipeline.

3. The method for obtaining the leakage and emission of volatile organic compounds from equipment and pipelines according to claim 1, characterized in that: Component type V of equipment or pipelines is valves, pumps, fittings, flanges, open valves or open pipelines, gas valves, liquid valves, light liquid pumps.

4. The method for obtaining the leakage and emission of volatile organic compounds from equipment and pipelines according to claim 1, characterized in that: TOC leakage mass emission rate E TOC (kg / h), the calculation formula is as follows: Among them, E TOC，0 Refers to the TOC leakage rate when the TOC leakage concentration C detection value is between 0 and 1ppm; E TOC，p Refers to the TOC leakage rate when the TOC leakage concentration C detection value is greater than or equal to 50000ppm; E TOC，f Refers to the TOC leakage rate when the TOC leakage concentration C detection value is between 1 and 50000ppm.

5. The method for obtaining the leakage and emission amount of volatile organic compounds in equipment and pipelines according to claim 1, characterized in that: The VOCs species composition of organic materials circulating in leaking equipment or pipelines can be obtained through the material balance table or sampling monitoring method within the enterprise's production process design plan.

6. The method for obtaining the leakage and emission of volatile organic compounds from equipment and pipelines according to claim 1, characterized in that: The relative response factor (RRF) of VOCs species i of leaked organic materials on the hydrogen flame ionization detector is obtained by using literature data or theoretical calculations related to the research on the hydrogen flame ionization detector response factor, or by using specific VOCs species for direct experimental testing. i .

7. A method for obtaining leakage and emission of volatile organic compounds from equipment and pipelines according to claim 6, characterized in that: The relative response factor selection process should match the referenced standard substance corresponding to the relative response factor, and select the response factor obtained by the same standard substance used for calibration of the leakage equipment or pipeline TOC leakage concentration detection equipment; If the referenced relative response factor corresponds to a standard substance that is different from the same standard substance used for calibration of the leakage equipment or pipeline TOC leakage concentration detection equipment, a proportional conversion correction can be performed using the response factors of the different standard substances on the hydrogen flame ionization detector.

8. The method for obtaining the leakage and emission of volatile organic compounds from equipment and pipelines according to claim 1, characterized in that: Calculate the proportion of carbon atoms P that respond to VOCs species i on the hydrogen flame ionization detector i , the calculation formula is as follows: P1:P2:…:P i =X1·RRF1·N1:X2·RRF2·N2:…:X i ·RRF i ·N i ; ∑ i P i ＝1； Among them, P i The percentage of carbon atoms that respond to the hydrogen flame ionization detector in the leaked organic material VOCs species i; X i is the volume percentage of VOCs species i in the leaked organic material; RRF i N is the relative response factor of VOCs species i of leaked organic materials on the hydrogen flame ionization detector; i is the number of carbon atoms N in the molecular formula of the VOCs species i of the leaked organic material i .

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