Perfluoroolefin fluorination end-capping device

Abstract

The utility model relates to a perfluoroolefin fluorination end-capping device, which comprises a perfluoroolefin storage tank, a fluorine nitrogen gas storage device, a gas mixer and a fixed bed reactor, the perfluoroolefin storage tank and the fluorine nitrogen gas storage device are respectively connected with the gas mixer through pipelines, and the gas mixer is connected with the fixed bed reactor through a pipeline. A gas compressor and a proportional valve are arranged on each pipeline, a catalyst pressing plate and a catalyst are arranged in the fixed bed reactor, an impurity absorption tower is arranged on one side of the fixed bed reactor, and the impurity absorption tower is connected with a condenser; perfluoroolefin and fluorine nitrogen are respectively conveyed to the gas mixer by the gas compressor through a pipeline to be mixed, then conveyed to the fixed bed reactor to react under the action of the catalyst, and the product passes through the impurity absorption tower and then is condensed and collected by the condenser, so that the conversion rate of the reaction is high, the selectivity of the reaction is good, and the device has the effect of higher overall product yield.

Description

Technical Field

[0001] The present application relates to the field of perfluoroolefin preparation equipment, and in particular to a perfluoroolefin fluorination and end-capping device. Background Art

[0002] Perfluoroolefins (PFOs) are a class of organic compounds containing perfluorocarbon groups, commonly used in the chemical, electronics, coatings, and other industrial sectors. Due to their excellent heat and chemical resistance, as well as their hydrophobic and oleophobic properties, PFOs are widely used in the manufacture of fluoropolymers, surfactants, lubricants, and sealing materials.

[0003] Perfluoroolefins require fluorination to improve their chemical stability, surface activity, and heat resistance. This is usually done using a gas-liquid reaction, where fluorine and nitrogen gases are introduced into the perfluoroolefin. The reaction is controlled by the fluorine and nitrogen gases, and mechanical stirring is used to ensure the reaction yield.

[0004] However, during the fluorination and capping process, a too fast or excessive aeration rate of fluorine and nitrogen can easily lead to excessive reaction, resulting in product bond breakage and reduced reaction selectivity, while a too slow aeration rate or too little aeration volume can cause the perfluoroolefin to fail to react completely, reducing the reaction conversion rate. Utility Model Content

[0005] In order to solve the problems of low conversion rate and low selectivity of perfluoroolefins, the present application provides a perfluoroolefin fluorination and capping device.

[0006] The present application provides a perfluoroolefin fluorination and capping device using the following technical solutions:

[0007] A perfluoroolefin fluorination and capping device comprises a perfluoroolefin storage tank, a fluorine-nitrogen gas reservoir, a gas mixer, and a fixed-bed reactor. The perfluoroolefin storage tank and the fluorine-nitrogen gas reservoir are respectively connected to the gas mixer via pipelines. The gas mixer is connected to the fixed-bed reactor via pipelines. A gas compressor and a proportional valve are provided on each of the pipelines. A catalyst pressure plate is provided in the fixed-bed reactor, on which a catalyst is placed. An impurity absorption tower is provided on one side of the fixed-bed reactor, the impurity absorption tower is connected to a side of the fixed-bed reactor away from the gas mixer, and a condenser is provided on one side of the impurity absorption tower.

[0008] By adopting the above technical solution, the perfluoroolefins in the perfluoroolefin storage tank and the fluorine and nitrogen in the fluorine and nitrogen storage are respectively transported to the gas mixer through pipelines via a gas compressor, and then transported to the fixed bed reactor after mixing. The mixed gas reacts under the action of the catalyst, and the hydrogen fluoride and unreacted fluorine gas in the gas product after the reaction are removed by an impurity absorption tower. The capped perfluoroolefin is condensed and collected by a condenser. By controlling the ratio of the mixed gas and the ventilation rate, the conversion rate of the reaction is guaranteed. The reaction process only occurs in the catalyst bed, thereby improving the selectivity of the reaction and the yield of the overall product.

[0009] Optionally, an electric heater is provided between the gas mixer and the fixed bed reactor, and the electric heater is used to heat the transported mixed gas.

[0010] By adopting the above technical solution, the electric heater heats the mixed gas to an appropriate temperature to prevent the condensation of perfluoroolefins due to thermal effects during transportation, thereby affecting transportation. At the same time, since the heating section of the reaction mixed gas is short after entering the fixed bed reactor, the preheating requirement in the reactor can be greatly reduced after heating, ensuring that the mixed gas enters the catalyst bed at an appropriate reaction temperature.

[0011] Optionally, the proportional valve includes a perfluoroolefin inlet valve and a fluorine-nitrogen inlet valve, the perfluoroolefin inlet valve is arranged on a pipeline on one side of the perfluoroolefin storage tank, and the fluorine-nitrogen inlet valve is arranged on a pipeline on one side of the fluorine-nitrogen storage tank.

[0012] By adopting the above technical solution, the raw materials are controlled by two air inlet valves to be transported to the gas mixer through the gas compressor in a certain proportion, so as to obtain the optimal mixed gas ratio and ventilation rate under the condition of consistent catalyst type particles, thereby ensuring that the reaction is complete and has a better conversion rate during the reaction process.

[0013] Optionally, the fixed bed reactor includes an inner tube and an outer tube, one end of the inner tube is connected to the pipeline on one side of the electric heater through an air inlet pipe, an air outlet pipe is provided at the end of the inner tube away from the air inlet pipe, and the air outlet pipe is connected to the pipeline on one side of the impurity absorption tower, the outer tube is sleeved on the outside of the inner tube, and the catalyst pressure plate is arranged on the inside of the inner tube.

[0014] By adopting the above technical solution, the mixed gas is introduced into the inner tube through the air inlet pipe at a higher temperature, contacts the catalyst powder inside, and is transported to the impurity absorption tower through the air outlet pipe after the reaction is completed, where the reaction speed is accelerated by the catalyst.

[0015] Optionally, the fixed bed reactor is provided with an electric heating jacket at the interlayer between the inner tube and the outer tube.

[0016] By adopting the above technical solution, the electric heating jacket ensures that the reactants are in gaseous form during the entire reaction process and pass through the catalyst to react.

[0017] Optionally, the catalyst pressure plate includes an upper pressure plate and a lower pressure plate, the upper pressure plate and the lower pressure plate are distributed parallel to each other and arranged parallel to the axis direction of the inner tube, the catalyst is located between the upper pressure plate and the lower pressure plate, the upper pressure plate is provided with an upper opening, and the lower pressure plate is provided with a lower opening.

[0018] By adopting the above technical solution, the mixed gas enters through the upper opening of the upper pressure plate and is output from the lower opening of the lower pressure plate after the reaction is completed. The overall reaction process is controlled to proceed only in the catalyst bed and the reaction stops when leaving the catalyst bed, thereby reducing the possibility of overreaction and improving the selectivity of the reaction.

[0019] Optionally, the upper pressing plate located at the upper opening and the lower pressing plate located at the lower opening are both provided with filter cloths, and the filter cloths seal the upper opening and the lower opening.

[0020] By adopting the above technical solution, the upper opening and the lower opening are sealed to ensure that the catalyst does not escape from the inlet and outlet, while ensuring the passage of gas.

[0021] Optionally, alkali metal oxides and water-absorbing particles are placed in the impurity absorption tower.

[0022] By adopting the above technical solution, the alkali metal oxide is used to absorb the residual fluorine gas and hydrogen fluoride gas in the reaction, and the water-absorbing particles are used to absorb the water mixed into the product due to the acid-base reaction through the alkali metal oxide.

[0023] Optionally, the condenser is a shell and tube condenser, the gas is transported through the tube side of the shell and tube condenser, and the condensed water is transported through the shell side of the shell and tube condenser.

[0024] By adopting the above technical solution, the vacuum pressure drop of the shell and tube condenser is small, and at the same time the contact area between the gas and the condensed water is extended, so the condensation effect is better.

[0025] In summary, this application includes at least one of the following beneficial technical effects:

[0026] 1. By controlling the mixed gas ratio and ventilation rate, the reaction conversion rate is guaranteed. The reaction process is only carried out in the catalyst bed, which improves the selectivity of the reaction and the yield of the overall product.

[0027] 2. The electric heater heats the mixed gas to the appropriate temperature to prevent condensation of perfluoroolefins during transportation. After heating, it enters the fixed bed reactor, greatly reducing the need for preheating in the reactor and ensuring that the mixed gas enters the catalyst bed at the appropriate reaction temperature. The electric heating jacket ensures that the reactants are in gas form throughout the reaction process and pass through the catalyst to react;

[0028] 3. The shell and tube condenser has a small vacuum pressure drop and at the same time extends the contact area between the gas and the condensed water, resulting in a better condensation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the connections between the various components of this application.

[0030] Figure 2 It is a cross-sectional schematic diagram of the fixed bed reactor of the present application along the inner tube axis direction.

[0031] Those skilled in the art will appreciate that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size and position of some elements in the drawings may be exaggerated relative to other elements to help improve understanding of the embodiments of the present invention.

[0032] Figure numerals: 1. Perfluoroolefin inlet valve; 2. Perfluoroolefin storage tank; 3. Fluorine-nitrogen inlet valve; 4. Fluorine-nitrogen storage tank; 5. Fluorine-nitrogen compressor; 6. Perfluoroolefin compressor; 7. Gas mixer; 8. Electric heater; 9. Mixed gas compressor; 10. Fixed bed reactor; 101. Inlet pipe; 102. Inner pipe; 103. Upper joint; 104. Outer pipe; 105. Upper pressure plate; 1051. Upper opening; 106. Lower pressure plate; 1061. Lower opening; 107. Outlet pipe; 108. Interface; 11. Impurity absorption tower; 12. Condensed water; 13. Condenser. DETAILED DESCRIPTION

[0033] The present application is further described in detail below with reference to the accompanying drawings.

[0034] The present application discloses a perfluoroolefin fluorination and end-capping device, referring to Figure 1 , including a perfluoroolefin storage tank 2, a fluorine-nitrogen gas storage tank 4, a gas mixer 7 and a fixed bed reactor 10. The perfluoroolefin storage tank 2 and the fluorine-nitrogen gas storage tank 4 are respectively connected to the gas mixer 7 through pipelines, and the gas mixer 7 is connected to the fixed bed reactor 10 through pipelines. A perfluoroolefin compressor 6 is provided on the pipeline on one side of the perfluoroolefin storage tank 2, and a fluorine-nitrogen gas compressor 5 is provided on the one side of the fluorine-nitrogen gas storage tank 4. A proportional valve is provided on each pipeline. The perfluoroolefin in the perfluoroolefin storage tank 2 and the fluorine-nitrogen gas in the fluorine-nitrogen gas storage tank 4 are respectively transported to the gas mixer 7 through the perfluoroolefin compressor 6 and the fluorine-nitrogen gas compressor 5 through the pipeline, and then transported to the fixed bed reactor 10 after mixing.

[0035] Reference Figure 1 and Figure 2 A catalyst pressure plate is provided within the fixed bed reactor 10, on which a catalyst is placed. An impurity absorption tower 11 is provided on one side of the fixed bed reactor 10. The impurity absorption tower 11 is connected to the side of the fixed bed reactor 10 facing away from the gas mixer 7. A condenser 13 is provided on one side of the impurity absorption tower 11. The mixed gas reacts under the action of the catalyst. The product after the reaction passes through the impurity absorption tower 11 to remove hydrogen fluoride and unreacted fluorine gas from the gas. The capped perfluoroolefin is condensed and collected by the condenser 13. By controlling the ratio of the mixed gas and the ventilation rate, the reaction conversion rate is guaranteed. The reaction process only occurs in the catalyst bed, which improves the selectivity of the reaction and the yield of the overall product.

[0036] Reference Figure 1 The proportional valve includes a perfluoroolefin inlet valve 1 and a fluorine-nitrogen inlet valve 3. The perfluoroolefin inlet valve 1 is arranged on a pipeline on one side of the perfluoroolefin storage tank 2, and the fluorine-nitrogen inlet valve 3 is arranged on a pipeline on one side of the fluorine-nitrogen storage tank 4. The perfluoroolefin inlet valve 1 and the fluorine-nitrogen inlet valve 3 respectively control the perfluoroolefin and fluorine-nitrogen gases to be transported to the gas mixer 7 in a certain proportion through the gas compressor, so as to obtain the optimal mixed gas ratio and ventilation rate under the condition of consistent catalyst type particles, thereby ensuring complete reaction during the reaction process and achieving a better conversion rate.

[0037] Reference Figure 1 An electric heater 8 is provided on one side of the gas mixer 7, and the electric heater 8 is connected to the gas mixer 7 through a pipeline. A mixed gas compressor 9 is provided on the side of the electric heater 8 away from the gas mixer 7, and one side of the mixer compressor is connected to the fixed bed reactor 10 through a pipeline. The electric heater 8 heats the mixed gas to a suitable temperature to prevent the condensation of perfluoroolefins due to thermal effects during transportation and thus affect transportation. At the same time, since the heating section of the reaction mixed gas is short after entering the fixed bed reactor 10, the preheating requirement in the reactor can be greatly reduced after entering the fixed bed reactor 10 after heating, thereby ensuring that the mixed gas enters the catalyst bed at a suitable reaction temperature.

[0038] Reference Figure 2 The fixed bed reactor 10 includes an inner tube 102 and an outer tube 104. One end of the inner tube 102 is connected to the pipeline through the air inlet pipe 101. An interface 108 is provided at one end of the inner tube 102. An upper joint 103 is provided on the air inlet pipe 101. The upper joint 103 is fastened to the fixed bed interface 108 by a threaded connection. The inner tube 102 is made of 316 stainless steel to ensure that the cleaning process after the reaction is completed is not corroded by the cleaning agent, so as to extend the service life of the fixed bed reactor 10 and reduce equipment costs.

[0039] Reference Figure 2An outlet pipe 107 is provided at the end of the inner tube 102 facing away from the inlet pipe 101. The outlet pipe 107 is connected to a pipeline on one side of the impurity absorption tower 11. The outer tube 104 is sleeved on the outside of the inner tube 102. An electric heating jacket is installed in the interlayer between the inner and outer tubes 102 and 104. The catalyst pressure plate is installed on the inside of the inner tube 102. The mixed gas enters the inner tube 102 through the inlet pipe 101, contacts the catalyst powder inside, and is transported to the impurity absorption tower 11 through the outlet pipe 107 after the reaction. The electric heating jacket ensures that the reactants are in gaseous form and pass through the catalyst to react throughout the reaction.

[0040] Reference Figure 2 The catalyst platen includes an upper platen 105 and a lower platen 106. The upper platen 105 and the lower platen 106 are arranged parallel to each other. The upper platen 105 is located in the inner tube 102 on the side facing the inlet pipe 101, and the lower platen 106 is located in the inner tube 102 on the side facing the outlet pipe 107. The upper platen 105 and the lower platen 106 are both arranged parallel to the axis of the inner tube 102. The catalyst is located between the upper platen 105 and the lower platen 106. The upper platen 105 is provided with an upper opening 1051, and the lower platen 106 is provided with a lower opening 1061. The mixed gas enters through the upper opening 1051 and is discharged from the lower opening 1061 after the reaction is completed. The overall reaction process is controlled to proceed only in the catalyst bed. The reaction stops when leaving the catalyst bed, reducing the possibility of overreaction and improving the selectivity of the reaction.

[0041] Reference Figure 2 , the upper pressure plate 105 is located at the upper opening 1051 and the lower pressure plate 106 is located at the lower opening 1061. The filter cloth seals the upper opening 1051 and the lower opening 1061. The filter cloth uses a 100-mesh or even finer pore size filter cloth to ensure that the catalyst does not escape from the inlet and outlet, while ensuring the passage of gas. After the reaction is completed, the filter cloth should be checked in time to see if it is intact to prevent the filter cloth from being damaged and causing the catalyst to escape, affecting the reaction. When the product infrared and other indicators drop or fail to meet the requirements, the filter cloth at the upper opening 1051 inlet and the lower opening 1061 outlet of the fixed bed pressure plate should be removed, the catalyst should be released and cleaned and dried, and new filter cloth and catalyst should be replaced.

[0042] Reference Figure 1 Alkali metal oxides and water-absorbing particles are placed in the impurity absorption tower 11. The alkali metal oxides are used to absorb the residual fluorine gas and hydrogen fluoride gas in the reaction, while the water-absorbing particles are used to absorb the water mixed into the product after the acid-base reaction through the alkali metal oxides.

[0043] The product is tested at the outlet of the impurity absorption tower 11. Compared with the traditional reactor, the gas leaving the kettle does not contain the product and can be directly absorbed by the alkali solution. Since the reaction product of the fixed bed reactor 10 is a gaseous mixture, after passing through the alkali metal oxide, the fluorine gas and hydrogen fluoride gas are absorbed to produce water. Therefore, it is necessary to test at the outlet of the impurity absorption tower 11 to ensure that no water enters the condensation stage. The additional water removal step or the failure to completely absorb the fluorine gas and hydrogen fluoride gas will lead to the generation of waste gas.

[0044] If the gas outlet indicators at the impurity absorption tower 11 are abnormal, the valve should be closed immediately and the reaction should be stopped. After all the gas in the absorption tower is discharged into the alkali solution, the alkali metal oxide and water-absorbing particles should be replaced with new ones before the valve is opened and the reaction can be resumed. At the same time, the alkali metal oxide and water-absorbing particles in the impurity absorption tower 11 should be replaced regularly, and the replacement frequency should be determined according to the actual reaction situation.

[0045] Reference Figure 1 The condenser 13 is a shell and tube condenser. The gas is transported through the tube side of the shell and tube condenser, and the condensed water 12 is transported through the shell side of the shell and tube condenser. The vacuum pressure drop of the shell and tube condenser is small, and at the same time, the contact area between the gas and the condensed water 12 is extended, and the condensation effect is better.

[0046] The implementation principle of a perfluoroolefin fluorination and capping device in an embodiment of the present application is as follows: at the initial stage of the reaction, catalyst selection and multiple tests should be carried out to obtain a suitable ventilation rate for this type of catalyst at a fixed particle size and a ratio of perfluoroolefin to fluorine-nitrogen gas in the mixed gas; the gas compressor extracts perfluoroolefin and fluorine-nitrogen gas from the storage tank, transports them to the gas mixer 7 through a pipeline, and then sends them to the fixed bed reactor 10 after being heated by the electric heater 8; before the reaction starts, the electric heating jacket should be turned on so that the temperature of the fixed bed reactor 10 reaches the reaction temperature before the mixed gas is introduced and contacts the catalyst for reaction; after the reaction is completed, the mixed gas is introduced into the impurity absorption tower 11; the product is tested at the outlet of the impurity absorption tower 11 to ensure that the product is not mixed with water; the product is introduced into the shell and tube condenser for condensation, and the gaseous product and nitrogen are condensed by the condenser 13 to obtain a liquid product and nitrogen.

[0047] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A perfluoroolefin fluorination and capping device, comprising a perfluoroolefin storage tank (2), a fluorine and nitrogen gas storage device (4), a gas mixer (7) and a fixed bed reactor (10), characterized in that: The perfluoroolefin storage tank (2) and the fluorine-nitrogen gas storage tank (4) are respectively connected to the gas mixer (7) through pipelines, and the gas mixer (7) is connected to the fixed bed reactor (10) through pipelines. A gas compressor and a proportional valve are provided on each of the pipelines. A catalyst pressure plate is provided in the fixed bed reactor (10), and a catalyst is placed on the catalyst pressure plate. An impurity absorption tower (11) is provided on one side of the fixed bed reactor (10), and the impurity absorption tower (11) is connected to the side of the fixed bed reactor (10) away from the gas mixer (7). A condenser (13) is provided on one side of the impurity absorption tower (11).

2. A perfluoroolefin fluorination and capping device according to claim 1, characterized in that: An electric heater (8) is provided between the gas mixer (7) and the fixed bed reactor (10), and the electric heater (8) is used to heat the transported mixed gas.

3. The perfluoroolefin fluorination and capping device according to claim 1, characterized in that: The proportional valve comprises a perfluoroolefin inlet valve (1) and a fluorine-nitrogen inlet valve (3), wherein the perfluoroolefin inlet valve (1) is arranged on a pipeline on one side of a perfluoroolefin storage tank (2), and the fluorine-nitrogen inlet valve (3) is arranged on a pipeline on one side of a fluorine-nitrogen storage tank (4).

4. A perfluoroolefin fluorination and capping device according to claim 2, characterized in that: The fixed bed reactor (10) comprises an inner tube (102) and an outer tube (104), one end of the inner tube (102) is connected to a pipeline on one side of the electric heater (8) through an air inlet pipe (101), an air outlet pipe (107) is provided at one end of the inner tube (102) away from the air inlet pipe (101), and the air outlet pipe (107) is connected to a pipeline on one side of the impurity absorption tower (11), the outer tube (104) is sleeved on the outside of the inner tube (102), and the catalyst pressure plate is provided on the inside of the inner tube (102).

5. A perfluoroolefin fluorination and capping device according to claim 4, characterized in that: The fixed bed reactor (10) is provided with an electric heating jacket at the interlayer between the inner tube (102) and the outer tube (104).

6. A perfluoroolefin fluorination and capping device according to claim 4, characterized in that: The catalyst pressure plate includes an upper pressure plate (105) and a lower pressure plate (106), the upper pressure plate (105) and the lower pressure plate (106) are distributed parallel to each other and are arranged parallel to the axial direction of the inner tube (102), the catalyst is located between the upper pressure plate (105) and the lower pressure plate (106), the upper pressure plate (105) is provided with an upper opening (1051), and the lower pressure plate (106) is provided with a lower opening (1061).

7. A perfluoroolefin fluorination and capping device according to claim 6, characterized in that: The upper pressing plate (105) located at the upper opening (1051) and the lower pressing plate (106) located at the lower opening (1061) are both provided with filter cloths, and the filter cloths seal the upper opening (1051) and the lower opening (1061).

8. The perfluoroolefin fluorination and capping device according to claim 1, characterized in that: Alkali metal oxides and water-absorbing particles are placed in the impurity absorption tower (11).

9. The perfluoroolefin fluorination and capping device according to claim 1, characterized in that: The condenser (13) is a shell-and-tube condenser, the gas is transported through the tube side of the shell-and-tube condenser, and the condensed water (12) is transported through the shell side of the shell-and-tube condenser.

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