A method and apparatus for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas.

Abstract

This invention provides a method and apparatus for treating exhaust gas from a ternary mixed gas of C4F7N / CO2 / O2, belonging to the field of electrical equipment. Centered on a concentration detection module and a gas adsorption module, it employs various molecular sieves and activated alumina adsorbents to adsorb C4F7N and CO2 from the exhaust gas. The gas concentration is detected using a portable gas chromatograph to evaluate the treatment effect. This method combines single-gas adsorption efficiency with weighted calculation of the total adsorption efficiency, and considers adsorbent usage time and cumulative treatment volume to obtain an efficiency index. Based on a preset threshold, it switches to a backup adsorption device or prepares a new adsorbent, dynamically optimizing the adsorption effect. This invention can significantly reduce the content of trace amounts of toxic C4F7N and the greenhouse gas CO2 in emitted gases, minimizing the impact of gas emissions on the atmospheric environment and providing a comprehensive exhaust gas treatment technology solution for the operation and maintenance of C4F7N / CO2 / O2 gas insulation equipment.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment, and in particular relates to a method and apparatus for treating exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas. Background Technology

[0002] Gas-insulated equipment using SF6, which has a strong greenhouse effect, as the insulating medium, such as gas-insulated switchgear (GIS) and gas-insulated transmission lines (GIL), are widely used in the power industry. However, the power industry's extensive use of SF6 inevitably leads to SF6 emissions and leaks, resulting in a year-on-year increase in atmospheric SF6 levels. Given the urgent need to limit SF6 emissions, the power industry urgently needs to find environmentally friendly insulating gases to replace SF6.

[0003] Currently, the C4F7N / CO2 / O2 ternary gas mixture has the potential to replace SF6 due to its excellent insulation properties, low gas power consumption (GWP), and high liquefaction temperature. Some gas-insulated equipment using C4F7N / CO2 / O2 as the medium has already been put into use. However, research shows that C4F7N has trace amounts of toxicity and cannot be directly emitted into the atmosphere. Furthermore, CO2, as a greenhouse gas, requires further treatment. Therefore, the treatment method for C4F7N / CO2 / O2 exhaust gas is of great significance for the operation and maintenance of C4F7N / CO2 / O2 gas-insulated equipment.

[0004] However, the application of C4F7N / CO2 / O2 ternary mixed gas is still in its early stages both domestically and internationally. There is no unified treatment device for C4F7N / CO2 / O2 ternary mixed gas exhaust gas, nor is a complete treatment method for it. The invention patent "Optimization Method for Compatibility of C4F7N / CO2 / O2 Ternary Mixed Gas with Metals in Equipment" (application number: CN202411622700.4) discloses gas sampling and treatment analysis after the reaction of C4F7N / CO2 / O2 ternary mixed gas, specifying that experimental sample gas should be collected every 2 hours using PVF sampling bags. However, this method only samples the experimental sample gas for detection and analysis, without mentioning how to treat the remaining experimental gas. Furthermore, the sampling bags are generally small in size and cannot be used for continuous treatment of C4F7N exhaust gas. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas. The C4F7N / CO2 / O2 ternary mixed gas exhaust gas treatment apparatus, with a concentration detection module and a gas adsorption module as core components, adopts the principle that various adsorbents have an adsorption effect on C4F7N and CO2. The concentration detection module evaluates the exhaust gas treatment effect of the C4F7N / CO2 / O2 ternary mixed gas and dynamically adjusts the equipment to change the adsorption effect, so as to significantly reduce the content of C4F7N and CO2 in the discharged mixed gas and minimize the impact of gas emissions on the atmospheric environment.

[0006] To achieve the above objectives, the present invention provides a method for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas, comprising the following steps: Step 1: Introduce a ternary gas mixture of C4F7N / CO2 / O2, and measure the concentrations of C4F7N and CO2 at the time of introduction, recording them as follows. and ; Step 2: Afterwards, the concentrations of C4F7N and CO2 after adsorption treatment are measured and recorded as follows. and And obtain the cumulative treatment volume V of the adsorbent; Step 3: Set the rated adsorption capacity and rated service life of the adsorbent, denoted as V0 and t0 respectively, and record the service time t during tail gas treatment; Step 4: Calculate the single-gas adsorption efficiency of C4F7N and CO2 based on the concentration detected in Step 1. Obtain the mixed gas adsorption efficiency by weighting the single-gas adsorption efficiency, and then calculate the adsorbent efficiency index S. Step 5: Determine whether a backup gas adsorption device is needed to continue the exhaust gas treatment process based on the adsorbent efficiency index. Step 6: Repeat steps 1 to 5 until all tail gas from the C4F7N / CO2 / O2 ternary mixed gas has been treated.

[0007] Preferred single-gas adsorption efficiencies for C4F7N and CO2: ; ; Mixed gas adsorption efficiency: ; in, The adsorption weighting coefficient for C4F7N is... This represents the adsorption weighting coefficient for CO2. The adsorption efficiency of the C4F7N and CO2 gases after weighting by adsorption weighting coefficients is given. The adsorption efficiency of C4F7N gas is given. The adsorption efficiency of CO2 gas is given.

[0008] Preferably, the adsorbent efficiency index S is calculated using the mixed gas adsorption efficiency, the cumulative treatment volume of the adsorbent, the rated adsorption capacity of the adsorbent, the rated service life of the adsorbent, and the service time t. The calculation formula is as follows: S= .

[0009] Preferably, determining whether a backup gas adsorption device is needed to continue the exhaust gas treatment process based on the adsorbent efficiency index includes: If the adsorbent efficiency index S is lower than the failure threshold, the tail gas treatment process is continued using a backup gas adsorption device, the failed adsorbent is unloaded and the corresponding device is switched to standby; if the adsorbent efficiency index S is lower than the warning threshold, it is necessary to equip the backup device with new adsorbent.

[0010] Preferably, the rated adsorption capacity and rated service life of the adsorbent are obtained by finding relevant manufacturer information or through testing.

[0011] A tail gas treatment device for a C4F7N / CO2 / O2 ternary mixed gas includes two core components: a concentration detection module and a gas adsorption module. A gas flow control unit is used to control the gas flow rate into the device; The inlet concentration detection unit is used to detect the concentrations of C4F7N and CO2 in the gas when it is introduced into the device. The C4F7N and CO2 gas adsorption unit and the backup gas adsorption unit are used to adsorb C4F7N and CO2 in the introduced gas. The outlet concentration detection unit is used to detect the concentration of C4F7N and CO2 in the gas after passing through the C4F7N and CO2 gas adsorption unit or the backup gas adsorption unit.

[0012] Preferably, the adsorbents for the C4F7N and CO2 gas adsorption units and the backup gas adsorption units are: 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 13X molecular sieve or activated alumina.

[0013] Preferably, the gas flow control unit has an accuracy of 0.1 mL / min.

[0014] Preferably, the inlet concentration detection unit and the outlet concentration detection unit are portable gas chromatograph detection units.

[0015] Therefore, the present invention employs the above-mentioned method and apparatus for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas, and the technical effects are as follows: (1) A tail gas treatment device for C4F7N / CO2 / O2 ternary mixed gas is given. C4F7N and CO2 in the mixed gas are adsorbed by a variety of effective adsorbents. The adsorbent efficiency index is obtained by detecting the gas chromatographic changes before and after adsorption and calculating to evaluate the tail gas treatment effect.

[0016] (2) A method for treating tail gas of C4F7N / CO2 / O2 ternary mixed gas is given. By dynamically adjusting the equipment to change the adsorption effect, the content of C4F7N and CO2 in the discharged mixed gas is greatly reduced so as to minimize the impact of gas emissions on the atmospheric environment. Attached Figure Description

[0017] Figure 1 Schematic diagram of a C4F7N / CO2 / O2 ternary mixed gas tail gas treatment device; Figure 2 Flowchart for the tail gas treatment of C4F7N / CO2 / O2 ternary mixed gas; Figure 3 The results of gas chromatography analysis of the C4F7N / CO2 / O2 ternary mixed gas tail gas before treatment in the case study; Figure 4 The results are gas chromatography analysis of the tail gas after treatment of the C4F7N / CO2 / O2 ternary mixed gas in the case. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0020] Example 1 like Figure 2 As shown, a method for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas includes the following steps: S1. Based on the type of adsorbent, obtain the rated adsorption capacity and rated service life V0 and t0 of the adsorbent. S2. A ternary gas mixture of C4F7N / CO2 / O2 is introduced into the exhaust gas treatment device at a fixed gas flow rate of 1 L / min. The concentrations of C4F7N and CO2 are detected by the inlet concentration detection unit and recorded as follows: and ; S3. Detect the concentrations of C4F7N and CO2 after adsorption treatment at the outlet concentration detection unit, and record them as follows: and The single-gas adsorption efficiencies of C4F7N and CO2 were calculated. , Adsorption efficiency with mixed gas The calculation formula is as follows: ; ; Mixed gas adsorption efficiency: ; in , These are the adsorption weighting coefficients for C4F7N and CO2. =95%, =80%.

[0021] S4. Determine the adsorbent's tail gas treatment time t and cumulative treatment volume V. Combine the adsorption efficiencies of C4F7N and CO2 with the gas's usage capacity and service life to calculate the adsorbent efficiency index S. The calculation formula is as follows: S= ; S5. If the adsorbent efficiency index S is lower than the failure threshold θ = 0.15, the tail gas treatment process will continue using the backup gas adsorption unit, the failed adsorbent will be unloaded, and the corresponding unit will be switched to standby; if the adsorbent efficiency index S is lower than the warning threshold θ pre =0.3, then it is necessary to complete the equipment for the backup unit to prepare new adsorbent.

[0022] S6. Repeat steps S2 to S5 until the tail gas adsorption treatment of the target C4F7N / CO2 / O2 ternary mixed gas is completed.

[0023] like Figure 1 As shown, a tail gas treatment device for a C4F7N / CO2 / O2 ternary mixed gas includes two core components: a concentration detection module and a gas adsorption module. The gas flow control unit is used to control the gas flow rate in the device. The accuracy of the gas flow control unit is 0.1 mL / min.

[0024] The inlet concentration detection unit is used to detect the concentrations of C4F7N and CO2 in the gas when it is introduced into the device. The C4F7N and CO2 gas adsorption unit and the backup gas adsorption unit are used to adsorb C4F7N and CO2 from the introduced gas; the adsorbents of the gas adsorption units are: 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 13X molecular sieve and activated alumina.

[0025] The outlet concentration detection unit is used to detect the concentrations of C4F7N and CO2 in the gas after passing through the C4F7N and CO2 gas adsorption unit or the backup gas adsorption unit. Both the inlet and outlet concentration detection units use portable gas chromatographs, and the detection error should be less than 0.5%.

[0026] Taking the tail gas treatment of a C4F7N / CO2 / O2 ternary mixed gas using 13X molecular sieve adsorbent as an example, where the rated adsorption capacity and rated service life of the 13X molecular sieve are V0 and t0 respectively, the detection results of the inlet concentration detection unit and the outlet concentration detection unit after continuous adsorption for t time are as follows: Figure 3 , Figure 4 As shown, where, Figure 4 Nitrogen gas was introduced during adsorption; the concentrations of C4F7N and CO2 detected before adsorption were respectively... =5%, =82%, the concentrations of C4F7N and CO2 obtained after adsorption were measured. , Both are 0. At this point, t / t0 and V / V0 are 0.6 and 0.3 respectively. The calculated adsorbent efficiency index S is 0.245, which is lower than the adsorbent warning threshold θ. pre =0.3, therefore, equipment for new adsorbents to complete the backup device is required.

[0027] Therefore, the present invention employs the above-mentioned method and apparatus for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas, which can significantly reduce the content of C4F7N, which has trace amounts of toxicity, and the greenhouse gas CO2 in the exhaust gas, thereby minimizing the impact of gas emissions on the atmospheric environment and providing a complete exhaust gas treatment technical solution for the operation and maintenance of C4F7N / CO2 / O2 gas insulation equipment.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for treating the exhaust gas of a C4F7N / CO2 / O2 ternary mixed gas, characterized in that, Includes the following steps: Step 1: Introduce a ternary gas mixture of C4F7N / CO2 / O2, and measure the concentrations of C4F7N and CO2 at the time of introduction, recording them as follows. and ; Step 2: Afterwards, the concentrations of C4F7N and CO2 after adsorption treatment are measured and recorded as follows. and And obtain the cumulative treatment volume V of the adsorbent; Step 3: Set the rated adsorption capacity and rated service life of the adsorbent, denoted as V0 and t0 respectively, and record the service time t during tail gas treatment; Step 4: Calculate the single-gas adsorption efficiency of C4F7N and CO2 based on the concentration detected in Step 1. Obtain the mixed gas adsorption efficiency by weighting the single-gas adsorption efficiency, and then calculate the adsorbent efficiency index S. Step 5: Determine whether a backup gas adsorption device is needed to continue the tail gas treatment process based on the adsorbent efficiency index. Step 6: Repeat steps 1 to 5 until all tail gas from the C4F7N / CO2 / O2 ternary mixed gas has been treated.

2. The tail gas treatment method for a C4F7N / CO2 / O2 ternary mixed gas according to claim 1, characterized in that, Single-gas adsorption efficiency of C4F7N and CO2: ； ； Mixed gas adsorption efficiency: ； in, The adsorption weighting coefficient for C4F7N is... This represents the adsorption weighting coefficient for CO2. The adsorption efficiency of the C4F7N and CO2 gases is calculated by weighting the adsorption weights. The adsorption efficiency of C4F7N gas is given. The adsorption efficiency of CO2 gas is given.

3. The tail gas treatment method for a C4F7N / CO2 / O2 ternary mixed gas according to claim 1, characterized in that, The adsorbent efficiency index S is calculated using the mixed gas adsorption efficiency, the cumulative volume of the adsorbent treated, the rated adsorption capacity of the adsorbent, the rated service life of the adsorbent, and the service time t. The calculation formula is as follows: S= 。 4. The tail gas treatment method for a C4F7N / CO2 / O2 ternary mixed gas according to claim 1, characterized in that, Determining whether a backup gas adsorption unit is needed to continue the exhaust gas treatment process based on the adsorbent efficiency index includes: If the adsorbent efficiency index S is lower than the failure threshold, the tail gas treatment process is continued using a backup gas adsorption device, the failed adsorbent is unloaded and the corresponding device is switched to standby; if the adsorbent efficiency index S is lower than the warning threshold, it is necessary to equip the backup device with new adsorbent.

5. The tail gas treatment method for a C4F7N / CO2 / O2 ternary mixed gas according to claim 1, characterized in that, The rated adsorption capacity and rated service life of the adsorbent are obtained by finding relevant manufacturer information or through testing.

6. A tail gas treatment device for a C4F7N / CO2 / O2 ternary mixed gas, characterized in that, The method for performing the method of claim 1 comprises two core components: a concentration detection module and a gas adsorption module. A gas flow control unit is used to control the gas flow rate into the device; The inlet concentration detection unit is used to detect the concentrations of C4F7N and CO2 in the gas when it is introduced into the device. The C4F7N and CO2 gas adsorption unit and the backup gas adsorption unit are used to adsorb C4F7N and CO2 in the introduced gas. The outlet concentration detection unit is used to detect the concentration of C4F7N and CO2 in the gas after passing through the C4F7N and CO2 gas adsorption unit or the backup gas adsorption unit.

7. The tail gas treatment device for a C4F7N / CO2 / O2 ternary mixed gas according to claim 6, characterized in that, The adsorbents for the C4F7N and CO2 gas adsorption units and the standby gas adsorption units are: 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 13X molecular sieve or activated alumina.

8. The tail gas treatment device for a C4F7N / CO2 / O2 ternary mixed gas according to claim 6, characterized in that, The gas flow control unit has an accuracy of 0.1 mL / min.

9. The tail gas treatment device for a C4F7N / CO2 / O2 ternary mixed gas according to claim 6, characterized in that, The inlet and outlet concentration detection units use portable gas chromatography detection units.

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