Environment-friendly mixed gas added with trifluoromethylsulfonyl fluoride and application of environment-friendly mixed gas in insulated power transmission pipeline

Abstract

The invention belongs to the technical field of insulating gases, and particularly relates to an environment-friendly mixed gas added with trifluoromethylsulfonyl fluoride and application of the environment-friendly mixed gas in an insulated power transmission pipeline. The environment-friendly mixed gas in the invention is composed of trifluoromethylsulfonyl fluoride (CF3SO2F) and a carrier gas, wherein the carrier gas is N2, CO2 or rare gas. The mixed gas has the advantages of low GWP, low toxicity, low boiling point and high insulating strength, can be applied to gas-insulated power transmission pipelines, not only can reduce the emission of greenhouse gases, but also can meet the insulating requirement in an environment at a low temperature of-25 DEG C or above, and has comprehensive indexes superior to those of most of current sulfur hexafluoride substitute gases.

Description

Technical Field

[0001] This invention belongs to the field of insulating gas technology, and more specifically relates to an environmentally friendly mixed gas with added trifluoromethanesulfonyl fluoride and its application in insulating power transmission pipelines. Background Technology

[0002] GIL (Gas Insulated Metal-Enclosed Transmission Line) is a type of transmission line that uses a conductive rod enclosed in a grounded metal casing to transmit electrical energy, employing pressurized gas insulation. Compared to existing overhead lines and cables, GIL transmission lines offer many significant advantages: large transmission capacity, excellent energy efficiency, high safety, high reliability, long service life, small footprint, and low overall cost. As a potential replacement for overhead lines and power cables, gas-insulated transmission lines are increasingly widely used in long-distance, high-capacity power transmission. The gas used in GILs must possess high insulation properties, low liquefaction temperature, low greenhouse effect, and non-toxicity to organisms.

[0003] Sulfur hexafluoride (SF6) is widely used in gas-insulated equipment due to its excellent insulation and arc-quenching properties, serving as an important insulating and arc-quenching medium and currently the primary insulating gas used in gas-insulated systems (GILs). However, SF6 has a global warming potential (GWP) of 24,300, meaning its greenhouse effect is 24,300 times that of CO2. Furthermore, SF6 has an atmospheric lifetime of up to 1,000 years, which can be considered almost permanent, contradicting current environmental protection principles. Therefore, finding environmentally friendly alternatives to SF6 has become a hot topic in the field of gas insulation research.

[0004] Currently, the most studied environmentally friendly insulating gases include: C4F7N and C5F. 10 O, trans-1,1,1,4,4,4-hexafluoro-2-butene [HFO-1336mzz(E)], CF3I, C6F 12 O, HFO-1234ze(E) (CF3CH=CHF, trans-1,3,3,3-tetrafluoropropylene), c-C4F8, etc. However, HFO-1336mzz(E), C4F7N, C5F... 10 O and C6F 12O has a high liquefaction temperature, with atmospheric liquefaction temperatures of 7.58℃, -4.7℃, 26.9℃, and 49℃ respectively, making its pure form unsuitable for use in most ambient temperatures. CF3I is classified as a Group 3 carcinogen and its industrial use is prohibited. c-C4F8 has a high GWP value, which also contradicts current environmental protection principles. HFO-1234ze(E) has lower insulation strength than SF6 gas and is easily decomposed during discharge, making it difficult to apply in practical GIL equipment. A comprehensive analysis considering factors such as liquefaction temperature, insulation strength, and GWP shows that none of these insulating gases can perfectly replace SF6, making the search for new environmentally friendly insulating gases imperative. Summary of the Invention

[0005] The purpose of this invention is to provide an environmentally friendly mixed gas containing trifluoromethanesulfonyl fluoride and its application in insulating power transmission pipelines, thereby solving the problems existing in the prior art. This invention proposes an environmentally friendly mixed gas containing trifluoromethanesulfonyl fluoride as a substitute for sulfur hexafluoride as an insulating gas in power equipment. Trifluoromethanesulfonyl fluoride has a low boiling point (-22°C), low GWP, and is non-toxic. Furthermore, its insulating strength is approximately 1.6 times that of sulfur hexafluoride, demonstrating superior overall performance compared to current sulfur hexafluoride and its substitute gases.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] One of the technical solutions of the present invention is to provide an environmentally friendly mixed gas with added trifluoromethanesulfonyl fluoride, wherein the environmentally friendly mixed gas is composed of trifluoromethanesulfonyl fluoride (CF3SO2F) and a carrier gas;

[0008] The carrier gas is N2, CO2, or a rare gas.

[0009] Furthermore, the rare gas is He.

[0010] Furthermore, the carrier gas is preferably N2.

[0011] Furthermore, the molar percentage of CF3SO2F in the environmentally friendly mixed gas is 10-50%.

[0012] In some specific implementations, the molar percentage of CF3SO2F in the environmentally friendly mixed gas is 10-20%.

[0013] In some preferred embodiments, the molar percentage of CF3SO2F in the environmentally friendly mixed gas is 12-14%, preferably 12% or 14%.

[0014] Preferably, the environmentally friendly mixed gas can be:

[0015] A combination of CF3SO2F with a molar percentage of 12% and a carrier gas with a molar percentage of 88%;

[0016] A combination of CF3SO2F with a molar percentage of 14% and a carrier gas with a molar percentage of 86%;

[0017] A combination of 10% CF3SO2F and 90% carrier gas;

[0018] A combination of 20% CF3SO2F and 80% carrier gas;

[0019] A combination of 30% CF3SO2F and 70% carrier gas;

[0020] A combination of CF3SO2F with a molar percentage of 40% and a carrier gas with a molar percentage of 60%;

[0021] A combination of CF3SO2F with a molar percentage of 50% and a carrier gas with a molar percentage of 50%.

[0022] The second technical solution of the present invention provides an application of the above-mentioned environmentally friendly mixed gas with added trifluoromethanesulfonyl fluoride in insulated power transmission pipelines.

[0023] Furthermore, the application in insulated power transmission pipelines includes low-pressure gas-insulated power transmission pipelines, medium-pressure gas-insulated power transmission pipelines, or high-pressure gas-insulated power transmission pipelines, with operating temperatures above -25°C.

[0024] In some specific implementation schemes, the operating temperature range is -25 to 40°C.

[0025] In some specific implementations, the insulated power transmission pipeline includes a busbar, a gas density sensor, a grounding switch, and cable terminals.

[0026] The present invention discloses the following technical effects:

[0027] The trifluoromethanesulfonyl fluoride gas (E=14.2 kV·mm) provided by this invention -1 The insulation strength is sulfur hexafluoride (E=8.9kV·mm). -1 It has a boiling point of -22℃, which is about 1.6 times that of sulfur hexafluoride. Compared with other sulfur hexafluoride substitutes in the prior art, it has a lower boiling point. When applied to gas-insulated power transmission pipelines, the gas has higher insulation strength and relatively lower filling pressure.

[0028] When the environmentally friendly mixed gas of this invention is trifluoromethanesulfonyl fluoride and N2, the environmentally friendly mixed gas operates at an ambient temperature of -25°C. It only requires charging the power equipment with 0.8 MPa of 12% CF3SO2F and the balance of N2, or 0.7 MPa of 14% CF3SO2F and the balance of N2, to achieve the same insulation strength as a 0.5 MPa sulfur hexafluoride device. Moreover, the estimated GWP of 12% CF3SO2F and the balance of N2 is <1, which has extremely low GWP and is non-toxic. It can meet the insulation strength required for power equipment applications and ensure that it is harmless to the environment (GWP <1, Ozone Depletion Potential = 0), reducing greenhouse gas emissions. It can be used as a sulfur hexafluoride alternative gas in GIL.

[0029] Furthermore, existing environmentally friendly gases used in gas-insulated power transmission pipelines (such as CF3I and c-C4F8) are prone to decomposition during use, resulting in the precipitation of solid substances such as elemental carbon during operation, which affects the insulation reliability of the equipment. In contrast, the environmentally friendly mixed gas in this invention has excellent insulation strength in the application and operation of high-voltage gas-insulated power transmission pipelines, and its chemical properties are stable during operation, without the precipitation of solid substances such as elemental carbon. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0031] Figure 1 This is a schematic diagram of the molecular structure of trifluoromethylsulfonyl fluoride;

[0032] Figure 2 The liquefaction temperature and relative insulation strength are given when the proportion of trifluoromethanesulfonyl fluoride changes under different carrier gas conditions.

[0033] Figure 3 This is a schematic diagram of the structure for filling the environmentally friendly mixed gas of the present invention in a 110kV three-phase common-enclosure power transmission pipeline;

[0034] Figure 4 This is a schematic diagram of the structure of filling a 220kV-1000kV single-phase power transmission pipeline with the environmentally friendly mixed gas of the present invention. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0037] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0038] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0039] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0040] Figure 1 This is a schematic diagram of the molecular structure of trifluoromethylsulfonyl fluoride.

[0041] In a specific embodiment of the present invention, the room temperature is 20°C.

[0042] Examples 1-20 and Comparative Examples 1-2

[0043] The composition of the environmentally friendly mixed gas with added trifluoromethanesulfonyl fluoride was determined, and its relative SF6 insulation strength, GWP, and boiling point were measured at room temperature. The results are shown in Table 1.

[0044] Table 1. Relative insulation strength and boiling point (at 0.5 MPa)

[0045] Example <![CDATA[Mole percentage (%) of CF3SO2F]]> Carrier gas margin <![CDATA[Relative SF6 insulation strength]]> GWP Boiling point (°C) Example 1 10 <![CDATA[N2]]> 0.75 ＜1 -38 Example 2 20 <![CDATA[N2]]> 0.86 ＜1 -25 Example 3 30 <![CDATA[N2]]> 0.94 ＜1 -11 Example 4 40 <![CDATA[N2]]> 1.01 ＜1 -4 Example 5 50 <![CDATA[N2]]> 1.07 ＜1 2 Example 6 10 <![CDATA[CO2]]> 0.68 ＜1 -38 Example 7 20 <![CDATA[CO2]]> 0.81 ＜1 -25 Example 8 30 <![CDATA[CO2]]> 0.90 ＜1 -11 Example 9 40 <![CDATA[CO2]]> 0.97 ＜1 -4 Example 10 50 <![CDATA[CO2]]> 1.03 ＜1 2 Example 11 10 He 0.58 ＜1 -38 Example 12 20 He 0.69 ＜1 -25 Example 13 30 He 0.78 ＜1 -11 Example 14 40 He 0.87 ＜1 -4 Example 15 50 He 0.93 ＜1 2 Example 16 16 <![CDATA[N2]]> 0.80 ＜1 -27 Example 17 14 <![CDATA[N2]]> 0.78 ＜1 -30 Example 18 12 <![CDATA[N2]]> 0.76 ＜1 -34 Example 19 12 <![CDATA[CO2]]> 0.70 ＜1 -34 Example 20 12 He 0.59 ＜1 -34 Comparative Example 1 5 <![CDATA[N2]]> 0.50 ＜1 -52 Comparative Example 2 60 <![CDATA[N2]]> 1.11 ＜1 8

[0046] Figure 2 The values ​​represent the liquefaction temperature and relative insulation strength corresponding to the changes in the proportion of trifluoromethanesulfonyl fluoride under different carrier gas conditions.

[0047] From the data in Table 1 and Figure 2It can be seen that when CF3SO2F is mixed with the carrier gas, the insulation strength of the mixed gas gradually increases with the increase of the proportion of CF3SO2F. Based on the data of 10% to 50% molar percentage, N2 can be regarded as the optimal carrier gas choice, with better synergistic effect under the same conditions. Meanwhile, in Comparative Examples 1 and 2, both excessively high and excessively low molar percentages of CF3SO2F are not conducive to practical applications. When the molar percentage of CF3SO2F is too high, although its insulation strength is high, its liquefaction temperature reaches 8°C, which is not applicable in most environments. When the molar percentage of CF3SO2F is too low, its insulation strength is only 50% of that of SF6 gas at the same pressure, which does not meet the application requirements of compact equipment structure.

[0048] Comparative Example 3

[0049] The environmentally friendly mixed gas composition by molar percentage is: 20% CF3SO2F, 3% O2 ​​and 77% N2.

[0050] At room temperature, its relative SF6 insulation strength is 0.87, GWP is <1, and boiling point is -25℃.

[0051] Test case

[0052] When the operating temperature of the power transmission pipeline is -25℃, the environmentally friendly mixed gas in Examples 1, 16~20 and Comparative Example 3 is used as the insulating gas. The critical breakdown field strength is tested under the conditions of inflation pressure of 0.5MPa, 0.6MPa, 0.7MPa and 0.8MPa. SF6 with an inflation pressure of 0.5MPa is used as a control example. The results are shown in Table 2.

[0053] Table 2 Critical breakdown field strength (kV / mm)

[0054] inflation pressure Example 1 Example 16 Example 17 Example 18 Example 19 Example 20 Comparative Example 3 Comparison Example 0.5MPa 17.53 18.93 18.23 17.76 16.36 13.79 20.33 23.37 0.6MPa 18.83 19.78 19.02 18.54 17.62 14.65 21.68 - 0.7MPa 20.86 21.25 21.18 20.95 19.54 16.43 23.12 - 0.8MPa 22.98 24.18 24.01 23.93 21.28 18.32 24.23 -

[0055] As shown in Table 2, the critical breakdown field strength increases with increasing inflation pressure; the critical breakdown field strength also increases with increasing CF3SO2F molar ratio; at the same pressure and CF3SO2F molar ratio, the critical breakdown field strength is higher when the carrier gas is N2 than when the carrier gas is CO2 or a rare gas. It should be noted that although Examples 16-17 and Comparative Example 3 have higher critical breakdown field strengths than SF6 at 0.8 MPa, their liquefaction temperatures are also relatively high, at -16℃ (Example 16), -19℃ (Example 17), and -10℃ (Comparative Example 3), respectively, limiting their usable ambient temperature range. Therefore, it is necessary to select specific examples based on both the usable temperature range and insulation strength requirements.

[0056] The environmentally friendly mixed gas (pressure 0.7 MPa, boiling point -25°C) from Example 17 was used as an insulating gas in 110kV three-phase co-containment transmission pipelines or 220kV~1000kV single-phase transmission pipelines. A schematic diagram is shown below. Figure 3 and Figure 4 As shown in Table 3, the components of the mixed gas decomposition products were detected after 60 days of operation.

[0057] Table 3

[0058] <![CDATA[CF3SO2F]]> <![CDATA[N2]]> Micro water / ppm Solid precipitation amount Before running 14% 88% 80 - After the 110kV three-phase common-enclosure transmission pipeline is put into operation 14% 88% 76 0mg After the 220kV~1000kV single-phase transmission pipeline is put into operation 14% 88% 89 0mg

[0059] Figure 3 This is a schematic diagram of the structure for filling the environmentally friendly mixed gas of the present invention in a 110kV three-phase common-enclosure power transmission pipeline; Figure 4 This is a schematic diagram of the structure of filling a 220kV-1000kV single-phase power transmission pipeline with the environmentally friendly mixed gas of the present invention.

[0060] As can be seen from Table 3, Example 17 exhibits good stability when using a gas pressure of 0.7 MPa. The proportion remains unchanged during long-term operation, with no solid precipitates and the trace water content remains essentially unchanged, thus meeting the equipment insulation reliability requirements.

[0061] Example 2 (pressure 0.7 MPa, boiling point -25°C) and Comparative Example 3 (pressure 0.5 MPa, boiling point -25°C) were used in a 110kV three-phase coaxial transmission pipeline. The composition of the decomposition products was measured after 60 days of operation, and the results are shown in Table 4.

[0062] Table 4

[0063] <![CDATA[CF3SO2F]]> <![CDATA[O2]]> <![CDATA[N2]]> Micro water / ppm <![CDATA[CO2 / ppm]]> Solid precipitation amount Example 2 Before running 20% 0% 80% 90 0 - After running Example 2 20% 0% 80% 87 0 0mg Comparative Example 3 before operation 20% 3% 77% 80 0 - After running Comparative Example 3 19.5% 3.2% 77.3% 95 6 0mg

[0064] As shown in Table 4, Example 2 exhibits good stability, maintaining a constant proportion and producing no solid precipitates during long-term operation. However, after operation, Comparative Example 3 shows a slight decrease in the molar proportion of CF3SO2F, an increase in trace water content, and the detection of CO2 gas. This indicates that the equipment may be experiencing discharge due to excessive field strength, failing to meet the equipment's insulation reliability requirements. Furthermore, the experiment demonstrates that the addition of O2 promotes CO2 generation. Therefore, it is not advisable to add O2 to the CF3SO2F mixed gas in practical applications.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0066] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An environmentally friendly mixed gas containing trifluoromethanesulfonyl fluoride, wherein the environmentally friendly mixed gas is composed of trifluoromethanesulfonyl fluoride and a carrier gas; The carrier gas is N2, CO2, or a rare gas.

2. The environmentally friendly mixed gas as described in claim 1, characterized in that, The carrier gas is N2.

3. The environmentally friendly mixed gas as described in claim 1, characterized in that, The rare gas is He.

4. The environmentally friendly mixed gas as described in claim 1, characterized in that, The molar percentage of trifluoromethanesulfonyl fluoride in the environmentally friendly mixed gas is 10-50%.

5. The environmentally friendly mixed gas as described in claim 1, characterized in that, The molar percentage of trifluoromethanesulfonyl fluoride in the environmentally friendly mixed gas is 10-20%.

6. The environmentally friendly mixed gas as described in claim 5, characterized in that, The molar percentage of trifluoromethanesulfonyl fluoride in the environmentally friendly mixed gas is 12-14%.

7. The application of an environmentally friendly mixed gas containing trifluoromethanesulfonyl fluoride as described in any one of claims 1 to 6 in insulated power transmission pipelines.

8. The application as described in claim 7, characterized in that, The application in gas-insulated power transmission pipelines includes low-pressure gas-insulated power transmission pipelines, medium-pressure gas-insulated power transmission pipelines, or high-pressure gas-insulated power transmission pipelines, with operating temperatures above -25°C.

9. The application as described in claim 8, characterized in that, The operating temperature range is -25~40℃.

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