Device for relieving pipe wall ash formation in production of hexafluoropropylene through tetrafluoroethylene cracking
By adding a mixed cooling cooler in tetrafluoroethylene cracking production, the problems of poor cooling effect and short operating cycle caused by ash in the tube wall of the column tube quencher are solved, and longer operating cycles and lower raw material and energy consumption are achieved.
Patent Information
- Application Number
- CN202421438544.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-24
- Publication Date
- 2025-04-22
- Estimated Expiration
- 2034-06-24
AI Technical Summary
During the production of hexafluoropropylene by tetrafluoroethylene cracking, the pipe walls of the tube quencher are prone to ash, resulting in poor cooling effect, short operating cycle, and frequent maintenance, which increases raw material consumption, energy consumption and safety risks.
Add a mixed cooling cooler to make the high-temperature cracking gas contact with the cooled liquid and cooled quickly, and then sprayed through the nozzle and entered the quencher. Use circulating water to further cool down and cool down, avoiding ash on the pipe wall.
It effectively solves the problems of poor cooling effect and short operating cycle caused by pipe-type quenching tube wall ash, extends the operating cycle to 3 months, reduces raw material consumption and energy consumption, and improves safety.
Smart Images
Figure CN222778053U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of chemical production, and specifically to a device for alleviating dust deposition on pipe walls by cracking tetrafluoroethylene to produce hexafluoropropylene. Background Art
[0002] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the utility model, and shall not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to ordinary technicians in this field.
[0003] In the process of tetrafluoroethylene cracking to produce hexafluoropropylene, the process gas after cracking needs to be quickly quenched to end the cracking. At present, the main quenching method in the industry is water quenching, that is, the process gas coming out of the cracking reactor enters the shell-and-tube heat exchanger, and the heat exchanger is immersed in a water tank (the water is flowing). After this quenching method has been running for a period of time, the inner wall of the shell-and-tube heat exchanger tube bundle will be ash (the ash is mainly produced by tetrafluoroethylene self-polymerization during the cracking process), and the heat exchange effect will deteriorate. In order to obtain the ideal heat exchange effect, the cracking reaction must be stopped regularly and the heat exchanger must be replaced and repaired. The general operation cycle is about 30 days. Since the maintenance requires frequent start-up and shutdown of the production line system, it will cause an increase in raw material consumption and energy consumption, and also increase the safety risk of operation. Utility Model Content
[0004] In view of the deficiencies in the above-mentioned prior art, the utility model provides a device for alleviating dust accumulation on the tube wall during the cracking of tetrafluoroethylene to produce hexafluoropropylene. The device adds a mixed quenching cooler to allow the high-temperature cracking gas to contact with a quenching liquid and cool down rapidly, thereby solving the problem of a short operating cycle of a shell-and-tube quench cooler due to poor cooling effect caused by dust accumulation on the inner wall of the tube.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] A device for alleviating dust deposition on tube walls by cracking tetrafluoroethylene to produce hexafluoropropylene comprises a cracking reactor, a mixed quenching cooler and a rapid cooler connected in sequence, a quenching liquid inlet pipe is arranged on the side of the mixed quenching cooler, a cracking material feed pipe is arranged above the mixed quenching cooler, the lower end of the cracking material feed pipe is in an oblique shape, and the end through which the quenching liquid enters is inserted into the oblique shape.
[0007] Preferably, the diameter of the end of the quenching liquid inlet pipe is smaller than the diameter of the remaining part of the quenching liquid inlet pipe.
[0008] Preferably, a nozzle is provided on the hybrid quenching and cooling device between the connection point of the quenching liquid inlet pipe and the lower end discharge port, and the diameter of the nozzle is smaller than the diameter of the rest of the hybrid quenching and cooling device.
[0009] Preferably, a temperature measuring point is provided at the outlet of the hybrid quenching and cooling device.
[0010] Preferably, the quencher comprises a heat exchange tube, a cooling water pool is arranged outside the heat exchange tube, two ends of the heat exchange tube are a quencher feed pipe and a quencher discharge pipe respectively, and the quencher feed pipe is located below the quencher discharge pipe.
[0011] The utility model has the following beneficial effects:
[0012] The utility model relates to a new method for cracking and quenching hexafluoropropylene by cracking tetrafluoroethylene. By adding a mixed quenching and cooling device, after the high-temperature cracking gas contacts with a quenching liquid (mainly octafluorocyclobutane and hexafluoropropylene), the quenching liquid absorbs heat and quickly gasifies, so that the high-temperature cracking gas is quickly cooled from 760°C to below 200°C, and then enters a quencher after being ejected from a nozzle, and is further quenched and cooled by circulating water to finally below 100°C, thereby solving the problem of a short operating cycle of a shell-and-tube quencher due to poor cooling effect caused by dust deposition on the inner wall of the shell-and-tube. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In order to more clearly illustrate the technical solution of the implementation mode of the utility model, the drawings required for use in the implementation mode will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.
[0014] Figure 1 It is the overall structure diagram of the utility model;
[0015] Figure 2 It is the structural diagram of the mixed quenching and cooling device;
[0016] Figure 3 It is the structural diagram of the quench cooler;
[0017] In the figure, 1-cracking reactor feed pipe, 2-cracking reactor, 3-quenching night inlet pipe, 4-mixing quenching cooler, 5-quencher, 6-quencher discharge pipe, 7-cooling water tank, 8-cracking material gas inlet, 9-quenching liquid inlet, 10-nozzle, 11-outlet temperature measuring point, 12-outlet pipe, 13, chiller feed pipe, 14, chiller discharge pipe, 15, cooling water tank. DETAILED DESCRIPTION
[0018] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0019] like Figure 1-3 As shown, the utility model discloses a device for alleviating dust deposition on tube walls during production of hexafluoropropylene by cracking tetrafluoroethylene, the device comprising a cracking reactor feed pipe 1, a cracking reactor 2, a quenching liquid inlet pipe 3, a mixed quenching and cooling cooler 4, a quencher 5, and a quencher outlet pipe 6; the mixed quenching and cooling cooler 4 comprises: a cracking material gas inlet 8, a quenching liquid inlet 9, a nozzle 10, an outlet temperature measuring point 11, and an outlet pipe 12; the quencher 5 comprises a heat exchange tube, a cooling water pool 15 is arranged outside the heat exchange tube, and a quencher feed pipe 13 is located below the quencher outlet pipe 14.
[0020] The feed pipe 1 of the cracking reactor is installed at the upper end of the cracking reactor 2, and the mixed quenching cooler 4 is installed between the feed pipe 1 of the cracking reactor and the quench cooler 5. The material enters the mixed quenching cooler 4 through the cracking material gas inlet 8 with an oblique mouth at the bottom. The side of the mixed quenching cooler 4 is connected to the quenching liquid inlet pipe 3. The end of the quenching liquid inlet pipe 3 is provided with an atomizing nozzle with a gradually decreasing diameter. The front of the nozzle is an oblique mouth. The quenching liquid sprayed by the atomizing nozzle is mixed with the high-temperature cracking material gas transported from the oblique mouth and enters the nozzle for spraying and cooling, which can effectively prevent the quenching liquid from being sprayed onto the inner wall of the tube.
[0021] The present application adds a mixed quenching and cooling device for mixing cracking gas and quenching liquid on the basis of the original system. After the high-temperature cracking gas contacts the quenching liquid (mainly octafluorocyclobutane and hexafluoropropylene), the quenching liquid absorbs heat and quickly vaporizes, so that the high-temperature cracking gas is quickly cooled from 760°C to below 200°C, and then is ejected from the nozzle and enters the shell-and-tube quench cooler, where it is further quenched by circulating water and finally cooled to below 100°C, thereby solving the problem of short operating cycle of the shell-and-tube quench cooler due to poor cooling effect caused by dust deposition on the inner wall of the shell and tube.
[0022] In some embodiments of the utility model, after the raw material is cracked in the cracking reactor, the high-temperature cracking process gas of 760°C enters the mixed quench cooler, and after the high-temperature cracking gas contacts the quenching liquid (mainly octafluorocyclobutane and hexafluoropropylene), the quenching liquid absorbs heat and quickly vaporizes, so that the high-temperature cracking gas is quickly cooled from 760°C to below 200°C, sprayed out from the nozzle and then enters the shell-and-tube quench cooler, which is further quenched by circulating water and finally cooled to below 100°C.
[0023] In some embodiments of the utility model, by adding a mixed quench cooler, the high-temperature cracked gas is brought into contact with a quenching liquid (mainly octafluorocyclobutane and hexafluoropropylene), and the quenching liquid absorbs heat and quickly vaporizes, so that the high-temperature cracked gas is quickly cooled from 760°C to below 200°C, thereby quickly ending the cracking. The temperature is reduced to below 200°C to avoid self-polymerization of unreacted tetrafluoroethylene, reduce the generation of self-polymerized material on the inner wall of the shell-and-tube quencher, and extend the operating period to 3 months.
[0024] In some embodiments of the utility model, a temperature measuring point is added to the outlet of the mixed quench cooler. The temperature measuring point and the quenching liquid entering the regulating valve form automatic control, which can effectively control the temperature after quenching to below 200°C, avoid the self-polymerization of unreacted tetrafluoroethylene, reduce the self-polymerization of the inner wall of the shell-and-tube quencher heat exchange tube bundle, and extend the operation period to 3 months.
[0025] The implementation effect of the utility model is compared with the traditional quench cooler in terms of raw material consumption, operation cycle, and power consumption as shown in the following table:
[0026]
[0027] By comparison, the operating cycle of the hybrid quench cooler + shell-and-tube quench cooler cooling method is significantly longer than the operating cycle of the traditional shell-and-tube quench cooler cooling method; the raw material consumption and electric energy consumption of the hybrid quench cooler + shell-and-tube quench cooler cooling method are significantly lower than those of the shell-and-tube quench cooler cooling method.
[0028] The above description is only the preferred implementation of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A device for alleviating dust deposition on pipe walls by cracking tetrafluoroethylene to produce hexafluoropropylene, characterized in that: The invention comprises a cracking reactor (2), a mixed quenching cooler (4) and a quencher (5) which are connected in sequence, wherein a quenching liquid inlet pipe (3) is arranged on the side of the mixed quenching cooler (4), and a cracking material feed pipe (8) is arranged above the mixed quenching cooler (4), wherein the lower end of the cracking material feed pipe (8) is in an oblique shape, and the end of the quenching liquid inlet pipe (3) is inserted into the oblique shape.
2. The device for alleviating dust deposition on the pipe wall by cracking tetrafluoroethylene to produce hexafluoropropylene according to claim 1, characterized in that: The diameter of the end of the quenching liquid inlet pipe (3) is smaller than the diameter of the remaining part of the quenching liquid inlet pipe (3).
3. The device for alleviating dust deposition on the pipe wall by cracking tetrafluoroethylene to produce hexafluoropropylene according to claim 1, characterized in that: A nozzle (10) is provided on the mixed quenching and cooling device (4) between the connection point of the quenching liquid inlet pipe (3) and the lower end discharge port, and the diameter of the nozzle is smaller than the diameter of the rest of the mixed quenching and cooling device (4).
4. The device for alleviating dust deposition on pipe wall by cracking tetrafluoroethylene to produce hexafluoropropylene according to claim 1, characterized in that: A temperature measuring point is provided at the outlet of the mixed quenching and cooling device (4).
5. The device for alleviating dust deposition on pipe wall by cracking tetrafluoroethylene to produce hexafluoropropylene according to claim 1, characterized in that: The quencher (5) comprises a heat exchange tube, a cooling water pool (15) is arranged outside the heat exchange tube, and the two ends of the heat exchange tube are respectively a quencher feed pipe (13) and a quencher discharge pipe (14), and the quencher feed pipe is located below the quencher discharge pipe.