C5-PFK mixed gas preparation device and method based on weighing and partial pressure combination method

Abstract

The C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method is characterized in that it includes a C5 insulating liquid storage cylinder, a dilution gas source, a C5 insulating liquid output pipeline, a dilution gas output pipeline, a dilution gas output branch pipeline, a mixed gas storage container, a mixed gas pipeline, and a vacuum pipeline; the air inlet end of the C5 insulating liquid output pipeline is connected to the outlet of the C5 insulating liquid storage cylinder and extends to the bottom of the cylinder, the air outlet end is connected to the air inlet of the mixed gas pipeline, the air inlet end of the dilution gas output pipeline is connected to the air outlet of the dilution gas source, and the air outlet end is also connected to the air inlet of the mixed gas pipeline. The air inlet of the dilution gas output branch pipeline is connected to the air outlet of the pressure reducing and stabilizing valve on the dilution gas output pipeline, the air outlet is connected to the inlet of the C5 insulating liquid storage cylinder, and the air outlet of the mixed gas pipeline is connected to the mixed gas storage container. The present invention also discloses a preparation method for C5-PFK mixed gas. The present invention can reduce the problems of low mixed gas pressure and low concentration caused by the liquefaction of C5 gas.

Description

Technical Field

[0001] The invention belongs to the technical field of mixed gas preparation, and in particular relates to a gas-liquid mixing device and a preparation method for preparing mixed insulating gas using a liquid fluid and a dilution gas. Background Art

[0002] C5-PFK is an insulating fluid with the molecular formula C5F 10 O (abbreviated as C5), under the same conditions, the insulation capacity of C5-PFK is 1.6 times that of sulfur hexafluoride gas (SF6). However, the saturated vapor pressure of C5-PFK is relatively low, and the liquefaction temperature is 26°C. In actual engineering applications, it needs to be mixed with diluent gas to increase the vapor pressure of the mixed gas and reduce the liquefaction temperature.

[0003] The mixing of two gas substances can be done by using a gas mass flow meter for dynamic gas distribution, and the mixed gas can be used directly without standing. However, this method is not suitable for the mixing of gas and liquid.

[0004] The partial pressure method is often used to mix C5-PFK and the diluent gas Air. The partial pressure method is greatly affected by temperature and cannot be prepared in large quantities on site, but it can be prepared in small batches under laboratory conditions. C5-PFK exists in liquid form in a cylinder. The partial pressure method requires a vacuum container to extract gaseous C5-PFK. During the extraction process, C5-PFK will continue to vaporize and absorb heat, causing the subsequent C5-PFK vaporization speed to be very slow and the temperature to drop. The temperature change will cause the pressure fluctuation of the prepared gas, resulting in a large concentration error of the prepared mixed gas. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a C5-PFK mixed gas preparation device based on a weighing and partial pressure combination method.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] The C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method of the present invention comprises a C5 insulating liquid storage cylinder, a dilution gas source, a C5 insulating liquid output pipeline, a dilution gas output pipeline, a dilution gas output branch pipeline, a mixed gas storage container, a mixed gas pipeline, and a vacuum pipeline;

[0008] The air inlet end of the C5 insulating liquid output pipeline is connected to the outlet of the C5 insulating liquid storage cylinder and extends to the bottom of the cylinder, and the air outlet end is connected to the air inlet of the mixed gas pipeline. The C5 insulating liquid output pipeline is provided with a first solenoid valve, a first heat exchanger, and a first needle valve in sequence from the air inlet end to the air outlet end;

[0009] The air inlet of the dilution gas output pipeline is connected to the air outlet of the dilution gas source, and the air outlet is also connected to the air inlet of the mixed gas pipeline. The dilution gas output pipeline is provided with a pressure reducing and stabilizing valve, a second heat exchanger, and a second needle valve in sequence from the air inlet to the air outlet;

[0010] The air inlet of the dilution gas output branch pipeline is connected to the air outlet of the pressure reducing and stabilizing valve on the dilution gas output pipeline, the air outlet of the dilution gas output branch pipeline is connected to the inlet of the C5 insulating liquid storage cylinder, and a second solenoid valve is provided on the dilution gas output branch pipeline;

[0011] The gas outlet of the mixed gas pipeline is connected to the mixed gas storage container, and a pressure sensor is provided on the mixed gas pipeline;

[0012] A first weighing device is provided under the C5 insulating liquid storage cylinder.

[0013] A second weighing device is provided under the dilution gas cylinder.

[0014] The vacuum port of the vacuum pipeline is also connected to the air inlet of the mixed gas pipeline, and is also connected to the dilution gas output pipeline and the C5 insulating liquid output pipeline. The vacuum pipeline is provided with a third solenoid valve and a vacuum pump, and the outlet of the vacuum pump is connected to a muffler.

[0015] The method for preparing a C5-PFK mixed gas based on a weighing and partial pressure combination method of the present invention comprises the following steps:

[0016] (1) First, evacuate the container and pipeline;

[0017] (2) Calculating the required weight of each component in the mixed gas to be prepared according to the weighing method, and calculating the partial pressure of each component in the mixed gas to be prepared according to the partial pressure principle;

[0018] (3) Prepare mixed gas.

[0019] The container and pipeline described in step (1) are evacuated, and the specific process is to open the first solenoid valve, the second and third solenoid valves, the vacuum pump, the first needle valve and the second needle valve, close the pressure reducing and stabilizing valve of the dilution gas source, and close the inlet and outlet valves on the C5 insulating liquid storage cylinder body; start the vacuum pump to evacuate the pipeline system and the mixed gas storage container except the C5 insulating liquid storage cylinder and its pipeline and the dilution gas source; when the pressure value of the pressure sensor is 10Pa, stop evacuating.

[0020] The step (2) of calculating the required weight of each component in the mixed gas to be prepared by weighing method is specifically performed as follows: when preparing the gas, the volume of the storage container of the mixed gas to be prepared, the C5 concentration and the dilution gas concentration are known, and the molar masses of C5 and the dilution gas are known. The mass of each component C5 fluid in the mixed gas to be prepared and the mass of the dilution gas, that is, the weight of C5 and the dilution gas, can be calculated by the following formula;

[0021]

[0022] Where:

[0023] m i ——The mass of component i in the mixed gas, in g;

[0024] x i ——the expected concentration of component i in the mixed gas, in mole fraction;

[0025] P f ——Final filling pressure of the mixed gas, in Pa;

[0026] V cy1 ——The volume of the mixed gas storage container to be prepared, in cubic meters (m 3 );

[0027] M i ——The molar mass of component i in the mixed gas, in g / mol;

[0028] R——gas constant (8.31451 J / mol k);

[0029] T——ambient temperature, in K;

[0030] Z f ——Temperature T and pressure P f The compression coefficient is 1 MPa. Different gases have different compression coefficients. f ≈1.

[0031] The step (2) of calculating the partial pressure of each component in the mixed gas to be prepared according to the partial pressure principle is specifically performed as follows: the partial pressure P of the component C5 in the mixed gas to be prepared is calculated according to the partial pressure principle. C5 ;

[0032] P C5 =P 总 *f C5

[0033] f C5 is the concentration of component C5 in the mixed gas, P 总 The final filling pressure of the C5 mixed gas to be prepared;

[0034] The partial pressure P of the diluent gas in the mixed gas to be prepared 稀释气体 ,

[0035] P 稀释气体 =P 总 -P C5 .

[0036] The specific operation of preparing the mixed gas in step (3) is to first stabilize the pressure of the pressure reducing and stabilizing valve to P C5 pressure, open the second and first solenoid valves, dilution gas flows into the top of the C5 liquid storage cylinder through the dilution gas output branch pipeline, C5 liquid is pressed into the first heat exchanger for vaporization, and the weight of C5 entering the mixed gas storage container is controlled by the combination of the first weighing device and the first needle valve. When the C5 intake volume reaches, close the second and first solenoid valves and the first needle valve;

[0037] Then fill the dilution gas into the container and adjust the pressure of the pressure reducing and stabilizing valve to P 总 The second needle valve and the second weighing device are combined to control the weight of the diluted gas air entering the mixed gas storage container. When the air intake volume reaches, the pressure reducing and stabilizing valve and the second needle valve are closed; the prepared mixed gas is kept stationary for 24 hours to ensure that the gas is fully mixed.

[0038] The concentration deviation of the mixed gas prepared according to this combination method is less than 0.3%.

[0039] In the structure, the pressure reducing and stabilizing solenoid valve reduces the pressure and stabilizes the dilution gas to ensure the stability of the airflow. The first solenoid valve controls the C5 insulating liquid, the second solenoid valve controls the dilution gas entering the C5 insulating liquid storage cylinder; the third solenoid valve controls the vacuum airflow. The second needle valve controls the flow of the dilution gas, and the first needle valve controls the flow of the C5 insulating liquid carried out. The second heat exchanger and the first heat exchanger keep the dilution gas and the C5 vaporized gas at the same temperature.

[0040] The beneficial effect of the present invention is that the gas distribution by the combined weighing and partial pressure method can reduce the liquefaction It can also reduce the problems of low mixed gas pressure and low concentration caused by the prepared gas, and slow gas distribution process caused by low vapor pressure of C5 gas and subsequent temperature reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0042] like Figure 1As shown, this embodiment takes C5-PFK liquid fluid and dilution gas Air as an example to illustrate a C5-PFK mixed gas preparation device and preparation method based on a weighing and partial pressure combination method.

[0043] The C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method of the present invention comprises a C5 insulating liquid storage cylinder 1, a dilution gas cylinder 2, a C5 insulating liquid output pipeline 3, a dilution gas output pipeline 4, a dilution gas output branch pipeline 5, a mixed gas storage container 6, a mixed gas pipeline 7, and a vacuum pipeline 8;

[0044] The air inlet end of the C5 insulating liquid output pipeline 3 is connected to the outlet of the C5 insulating liquid storage cylinder 1 and extends to the bottom of the cylinder, and the air outlet end is connected to the air inlet of the mixed gas pipeline 7. The C5 insulating liquid output pipeline 3 is provided with a first solenoid valve 9a, a first heat exchanger 10a, and a first needle valve 11a in sequence from the air inlet end to the air outlet end;

[0045] The inlet end of the dilution gas output pipeline 4 is connected to the outlet of the dilution gas cylinder 2, and the outlet end is also connected to the inlet of the mixed gas pipeline 7. The dilution gas output pipeline 4 is provided with a pressure reducing and stabilizing valve 12, a second heat exchanger 10b, and a second needle valve 11b in sequence from the inlet end to the outlet end;

[0046] The air inlet of the dilution gas output branch pipeline 5 is connected to the air outlet of the pressure reducing and stabilizing valve 12 on the dilution gas output pipeline 4, and the air outlet of the dilution gas output branch pipeline 5 is connected to the inlet of the C5 insulating liquid storage cylinder 1. The dilution gas output branch pipeline 5 is provided with a second solenoid valve 9b;

[0047] The gas outlet of the mixed gas pipeline 7 is connected to the mixed gas storage container 6, and a pressure sensor 13 is provided on the mixed gas pipeline 7; a first weighing device 16a and a second weighing device 16b are provided under the C5 insulating liquid storage cylinder 1 and the dilution gas cylinder 2, respectively.

[0048] The vacuum port of the vacuum pipeline 8 is also connected to the air inlet of the mixed gas pipeline 7, and is also connected to the dilution gas output pipeline 4 and the C5 insulating liquid output pipeline 3. The vacuum pipeline 8 is provided with a third solenoid valve 11c and a vacuum pump 14, and the outlet of the vacuum pump 14 is connected to a muffler 15.

[0049] The method for preparing a C5-PFK mixed gas based on a weighing and partial pressure combination method of the present invention comprises the following steps:

[0050] (1) Evacuate the container and pipeline;

[0051] (2) Calculating the required weight of each component in the mixed gas to be prepared according to the weighing method, and calculating the partial pressure of each component in the mixed gas to be prepared according to the partial pressure principle;

[0052] (3) Prepare mixed gas.

[0053] The specific process of evacuating the container and pipeline in step (1) is as follows: opening the first solenoid valve 9a, the second and third solenoid valves 9b and 9c, the vacuum pump 14, the first needle valve 11a and the second needle valve 11b, closing the pressure reducing and stabilizing valve 12 of the dilution gas cylinder 2, and closing the inlet and outlet valves on the body of the C5 insulating liquid storage cylinder 1; starting the vacuum pump 14 to evacuate the pipeline system and the mixed gas storage container 6 except the C5 insulating liquid storage cylinder 1 and its pipeline and the dilution gas cylinder 2; and stopping the evacuation when the pressure value of the pressure sensor 13 is 10Pa.

[0054] The step (2) of calculating the weight of each component in the mixed gas to be prepared by weighing method is specifically performed as follows: when preparing the gas, the volume of the storage container of the mixed gas to be prepared, the C5 concentration and the dilution gas concentration are known, such as the pre-prepared 20L, pressure 800kPa, concentration 10% C5 mixed gas , the diluent gas is dry air, then the molar masses of C5 and diluent air are known, which are 166 and 29 respectively. The mass of each component C5 fluid and the mass of diluent air in the mixed gas to be prepared can be calculated by the following formula, that is, the weight of C5 and diluent air;

[0055]

[0056] Where:

[0057] m i ——The mass of component i in the mixed gas, in g;

[0058] x i ——the expected concentration of component i in the mixed gas, in mole fraction;

[0059] P f ——Final filling pressure of the mixed gas, in Pa;

[0060] V cy1 ——The volume of the mixed gas storage container to be prepared, in cubic meters (m 3 );

[0061] M i ——The molar mass of component i in the mixed gas, in g / mol;

[0062] R——gas constant (8.31451 J / mol k);

[0063] T——ambient temperature, in K;

[0064] Z f ——Temperature T and pressure P fThe compression coefficient is 1 MPa. Different gases have different compression coefficients. f ≈1.

[0065] The specific operation of calculating the partial pressure of each component in the mixed gas to be prepared according to the partial pressure principle in step (2) is as follows: taking the preparation of 20L of C5 mixed gas with a pressure of 800 kPa and a concentration of 10% as an example, the partial pressure P of the component C5 in the mixed gas to be prepared is calculated according to the partial pressure principle. C5 ,

[0066] P C5 =P 总 *f C5 =800*10 3 *10%=80*10 3 Pa,

[0067] f C5 The concentration of component C5 in the mixed gas is 10%, P 总 The final filling pressure of the mixed gas to be configured is 800kPa;

[0068] The partial pressure P of the diluent gas in the mixed gas to be prepared 稀释气体 ,

[0069] P 稀释气体 =P 总 -P C5 =800*10 3 -80*10 3 =720*10 3 Pa.

[0070] The specific operation of preparing the mixed gas in step (3) is as follows:

[0071] The pressure of the pressure reducing and stabilizing valve is stabilized to P C5 pressure, open the second and first solenoid valves 9b, 9a, the dilution gas flows into the top of the C5 liquid storage cylinder 1 through the dilution gas output branch pipeline 5, the C5 liquid is pressed into the first heat exchanger 10a for vaporization, and the weight of the C5 entering the mixed gas storage container 6 is controlled by the combination of the first weighing sensor 16a and the first needle valve 11a. When the C5 intake volume reaches, close the second and first solenoid valves 9b, 9a and the first needle valve 11a;

[0072] Then fill the dilution gas into the container and adjust the pressure of the pressure reducing and stabilizing valve to P 总 The second needle valve 11b and the second weighing sensor 16b are combined to control the weight of the diluted gas air entering the mixed gas storage container 6. When the air intake volume reaches, the pressure reducing and stabilizing valve 12 and the second needle valve 11b are closed; the prepared mixed gas is kept stationary for 24 hours to ensure that the gas is fully mixed.

[0073] It has been confirmed by multiple experiments that the concentration deviation of the mixed gas prepared according to this combination method is less than 0.3%.

[0074] In the structure, the pressure reducing and stabilizing solenoid valve reduces the pressure and stabilizes the dilution gas to ensure the stability of the airflow. The first solenoid valve controls the C5 insulating liquid, the second solenoid valve controls the dilution gas entering the C5 insulating liquid storage cylinder; the third solenoid valve controls the vacuum airflow. The second needle valve controls the flow of the dilution gas, and the first needle valve controls the flow of the C5 insulating liquid carried out. The second heat exchanger and the first heat exchanger keep the dilution gas and the C5 vaporized gas at the same temperature.

[0075] The beneficial effect of the present invention is that the gas distribution by the combined weighing and partial pressure method can reduce the liquefaction It can also reduce the problems of low mixed gas pressure and low concentration caused by the prepared gas, and slow gas distribution process caused by low vapor pressure of C5 gas and subsequent temperature reduction.

[0076] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A C5-PFK mixed gas preparation device based on a combined weighing and partial pressure method, characterized in that: Including C5 insulating liquid storage cylinder, dilution gas source, C5 insulating liquid output pipeline, dilution gas output pipeline, dilution gas output branch pipeline, mixed gas storage container, mixed gas pipeline, vacuum pipeline; The air inlet end of the C5 insulating liquid output pipeline is connected to the outlet of the C5 insulating liquid storage cylinder and extends to the bottom of the cylinder, and the air outlet end is connected to the air inlet of the mixed gas pipeline. The C5 insulating liquid output pipeline is provided with a first solenoid valve, a first heat exchanger, and a first needle valve in sequence from the air inlet end to the air outlet end; The air inlet of the dilution gas output pipeline is connected to the air outlet of the dilution gas source, and the air outlet is also connected to the air inlet of the mixed gas pipeline. The dilution gas output pipeline is provided with a pressure reducing and stabilizing valve, a second heat exchanger, and a second needle valve in sequence from the air inlet to the air outlet; The air inlet of the dilution gas output branch pipeline is connected to the air outlet of the pressure reducing and stabilizing valve on the dilution gas output pipeline, the air outlet of the dilution gas output branch pipeline is connected to the inlet of the C5 insulating liquid storage cylinder, and a second solenoid valve is provided on the dilution gas output branch pipeline; The gas outlet of the mixed gas pipeline is connected to the mixed gas storage container, and a pressure sensor is provided on the mixed gas pipeline; A first weighing device is provided under the C5 insulating liquid storage cylinder.

2. The C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method according to claim 1, characterized in that: A second weighing device is provided under the dilution gas cylinder.

3. The C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method according to claim 1 or 2, characterized in that: The vacuum port of the vacuum pipeline is also connected to the air inlet of the mixed gas pipeline, and is also connected to the dilution gas output pipeline and the C5 insulating liquid output pipeline. The vacuum pipeline is provided with a third solenoid valve and a vacuum pump, and the outlet of the vacuum pump is connected to a muffler.

4. A gas distribution method of a C5-PFK mixed gas distribution device based on a weighing and partial pressure combination method as described in any one of claims 2 to 3, characterized in that: The following steps are included: (1) First, evacuate the container and pipeline; (2) Calculating the required weight of each component in the mixed gas to be prepared according to the weighing method, and calculating the partial pressure of each component in the mixed gas to be prepared according to the partial pressure principle; (3) Prepare mixed gas.

5. The preparation method of the C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method according to claim 4, characterized in that: The container and pipeline described in step (1) are evacuated. The specific process is to open the first solenoid valve, the second and third solenoid valves, the vacuum pump, the first needle valve and the second needle valve, close the pressure reducing and stabilizing valve of the dilution gas source, and close the inlet and outlet valves on the C5 insulating liquid storage cylinder body; start the vacuum pump to evacuate the pipeline system and the mixed gas storage container except the C5 insulating liquid storage cylinder and its pipeline and the dilution gas source; when the pressure value of the pressure sensor is 10Pa, stop evacuating.

6. The preparation method of the C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method according to claim 4, characterized in that: The step (2) of calculating the weight of each component in the mixed gas to be prepared by weighing method is specifically performed as follows: When preparing gas, the volume of the storage container of the mixed gas to be prepared, the concentration of C5 and the concentration of the diluent gas are known, and the molar mass of C5 and the diluent gas is known. The mass of each component C5 fluid and the mass of the diluent gas in the mixed gas to be prepared, that is, the weight of C5 and the diluent gas, can be calculated by the following formula; Where: m i ——The mass of component i in the mixed gas, in g; x i ——the expected concentration of component i in the mixed gas, in mole fraction; P f ——Final filling pressure of the mixed gas, in Pa; V cy1 ——The volume of the storage container of the C5 mixed gas to be prepared, in cubic meters (m 3 ); M i ——The molar mass of component i in the mixed gas, in (g / mol); R——gas constant (8.31451 J / mol k); T——ambient temperature, in K; Z f ——Temperature T and pressure P f The compression coefficient is 1 MPa. Different gases have different compression coefficients. f ≈1.

7. The preparation method of the C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method according to claim 4, characterized in that: The specific operation of calculating the partial pressure of each component in the mixed gas to be prepared according to the partial pressure principle in step (2) is as follows: Calculate the partial pressure P of component C5 in the mixed gas to be prepared by the partial pressure principle C5 , P C5 =P 总 *f C5 f C5 is the concentration of component C5 in the mixed gas, P 总 The final filling pressure of the C5 mixed gas to be prepared; The partial pressure P of the diluent gas in the mixed gas to be prepared 稀释气体 , P 稀释气体 =P 总 -P C5 。 8. The preparation method of the C5-PFK mixed gas preparation device based on the weighing and partial pressure combination method according to claim 4, characterized in that: The specific operation of preparing the mixed gas in step (3) is as follows: First, stabilize the pressure of the pressure reducing and stabilizing valve to P C5 Pressure, P C5 is the partial pressure of C5 in the mixed gas to be prepared, the second and first solenoid valves are opened, the dilution gas flows into the top of the C5 liquid storage cylinder through the dilution gas output branch pipeline, the C5 liquid is pressed into the first heat exchanger for vaporization, and the weight of C5 entering the mixed gas storage container is controlled by the combination of the first weighing device and the first needle valve. When the C5 intake volume reaches, the second and first solenoid valves and the first needle valve are closed; Then fill the dilution gas into the container and adjust the pressure of the pressure reducing and stabilizing valve to P 总 , P 总 To achieve the final filling pressure of the C5 mixed gas to be prepared, the second needle valve is combined with the second weighing device installed under the dilution gas cylinder to control the weight of the dilution gas air entering the mixed gas storage container. When the air intake volume reaches, the pressure reducing and stabilizing valve and the second needle valve are closed; the prepared mixed gas is kept stationary for 24 hours to ensure that the gas is fully mixed.

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