Monochlorodifluoromethane production and separation device
By designing a device including a fluorination reactor, a fluorinated product concentration tower, a disproportionation reactor, a pre-concentration tower and a tower overhead condenser, the existing difluorinated monochloromethane production and separation devices have been solved, and efficient difluorinated monochloromethane production and effective utilization of by-products has been achieved.
Patent Information
- Application Number
- CN202422192833.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-09-06
AI Technical Summary
The existing difluoromonomethane production and separation devices have problems of high energy consumption and inconvenient operation, especially during wet separation, the exhaust gas cannot be effectively utilized, resulting in an increase in energy consumption.
A device including a fluorination reactor, a fluorinated product concentration tower, a dispersion reactor, a pre-concentration tower and a tower overhead condenser was designed. The dispersion reactor was used to disperse the trifluoromethane and chloroform to generate difluoromethane, and the by-product dichloromethane and hydrogen chloride were reused through multi-stage condensation and reflux tubes.
The continuous production and operation of difluoromonochloromethane is achieved, which reduces energy consumption and improves the convenience of operation. The utilization rate of each material is high, and the by-products are effectively utilized.
Smart Images
Figure CN222984338U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a chemical product production and separation device, in particular to a difluorochloromethane production and separation device. Background Art
[0002] Difluorochloromethane is an environmental-friendly refrigerant with low ozone layer depletion, and is also the main raw material of polytetrafluoroethylene, fluororesin and fluororubber, and has wide applications in industry. In recent years, the domestic demand for it has increased rapidly. Difluorochloromethane is a colorless gas with a molecular weight of 86.47, a boiling point of -40.88°C, a slight sweet smell, non-flammable and non-explosive when mixed with air. Under normal use conditions, it has no irritation to the skin and has high thermal stability and chemical stability. Industrially, it is usually prepared by reacting chloroform with hydrogen fluoride under the action of a catalyst SbCl5. During the reaction, due to the change of the activity of the catalyst, trifluoromethane with a boiling point of -84°C, dichlorofluoromethane with a boiling point of 8.9°C, and hydrogen chloride with a boiling point of -85°C will be generated. The product separation technology is divided into two types: dry separation and wet separation. In wet separation, the product generated in the reaction kettle is washed with water, deacidified, and then purified by multi-stage cooling with chilled brine to obtain a qualified product. However, there are still uncondensed gases in the material in the intermediate tank after a series of purification and treatment of the products and by-products in wet separation, which are discharged or incinerated as tail gas. In dry separation, the tail gas is separated from trifluoromethane and hydrogen chloride by absorption. Hydrogen chloride is absorbed to produce hydrochloric acid, and trifluoromethane is incinerated. Although trifluoromethane can be used to prepare hydrofluoric acid after incineration, the energy consumption is large. Gas membrane separation technology is a new separation technology, which has the advantages of low energy consumption, small floor area, simple process, convenient operation, high purity of separated products, etc. compared with conventional separation technologies. However, in actual production, it is restricted by production costs and production scale. Summary of the Utility Model
[0003] The technical problem to be solved by the utility model is to provide a difluorochloromethane production and separation device, which can be continuously produced and operated, reduce energy consumption and is convenient to operate by using this device.
[0004] To solve the above technical problems, the utility model discloses a difluorochloromethane production and separation device, which includes a fluorination reaction kettle and a fluorination product concentration tower connected to the fluorination reaction kettle. The fluorination product concentration tower is connected to a difluorochloromethane product tank, and the fluorination product concentration tower is also connected to a disproportionation reactor. The disproportionation reactor is connected to a disproportionation product concentration tower through a pre-concentration tower. A pre-cooler is arranged on the outer periphery of the pre-concentration tower, and a top condenser is arranged on the outer periphery of the top of the disproportionation product concentration tower. The bottom of the pre-concentration tower is connected to the fluorination reaction kettle through a second reflux pipe.
[0005] Further, the bottom of the fluorination product concentrator is connected to the fluorination reactor through a first reflux pipe, and the incompletely fluorinated dichloromonofluoromethane is returned to the fluorination reactor 1 through the first reflux pipe 8 to continue participating in the reaction.
[0006] Further, the disproportionation reactor is a tubular reactor, and several heating tubes are arranged inside.
[0007] Further, chloroform or a mixture of chloroform and a catalyst is filled between the heating tubes.
[0008] Further, the top condenser and the pre-cooler are both connected to a chilled brine system.
[0009] By setting up a disproportionation reactor in the present utility model, trifluoromethane and hydrogen chloride generated by the fluorination reaction are introduced into the disproportionation reactor, so that trifluoromethane undergoes a disproportionation reaction with chloroform in the disproportionation reactor to further generate difluoromonochloromethane and dichloromonofluoromethane. Then, after cooling in the pre-concentrator, the high-boiling product dichloromonofluoromethane is condensed and returned to the fluorination reactor to participate in the fluorination reaction. Difluoromonochloromethane and hydrogen chloride are further condensed and separated in the disproportionation product concentrator due to the difference in boiling points. Difluoromonochloromethane is used as the target product, and hydrogen chloride is further utilized. At the same time, the present utility model also provides a first reflux pipe at the bottom of the fluorination product concentrator, which is connected to the fluorination reactor, so that the by-product dichloromonofluoromethane generated by the fluorination reaction is condensed and returned to the fluorination reactor to further participate in the reaction. The present utility model can recycle the generated by-product trifluoromethane, achieving the effect of turning waste into treasure, effectively separating the reaction products, having a high utilization rate of each material, being able to operate continuously, reducing energy consumption, and being convenient to operate. Description of the Drawings
[0010] Figure 1 is a structural schematic diagram of the present utility model;
[0011] Figure 2 is a cross-sectional structural schematic diagram of the disproportionation reactor.
[0012] Reference numerals in the figures: 1 - fluorination reactor; 2 - fluorination product concentrator; 3 - disproportionation reactor; 3.1 - heating tube; 4 - disproportionation product concentrator; 5 - pre-concentrator; 6 - top condenser; 7 - pre-cooler; 8 - first reflux pipe; 9 - second reflux pipe. Detailed Embodiments
[0013] The following further explains the present invention in conjunction with embodiments. The following embodiments are only used to illustrate the present utility model, but do not limit the scope of implementation of the present utility model.
[0014] Embodiment 1
[0015] As Figure 1As shown in the figure, the production and separation device for chlorodifluoromethane of the present utility model includes a fluorination reactor 1, a fluorination product concentration tower 2, a disproportionation reactor 3, a pre-concentration tower 5, and a disproportionation product concentration tower 4 that are connected in sequence. A pre-cooler 7 is arranged on the outer periphery of the pre-concentration tower 5, and a top condenser 6 is arranged on the outer periphery of the top of the disproportionation product concentration tower 4. Both the pre-cooler 7 and the top condenser 6 are connected to the chilled brine system, and respectively enter from the Figure 1 water inlet shown in the figure and exit from the water outlet to form a cycle. The disproportionation reactor 3 is a tubular reactor, and is internally provided with 4 - 6 heating tubes 3.1 (as Figure 2 shown in the figure). Chloroform, or a mixture of chloroform and a catalyst, is filled between the heating tubes 3.1. The catalyst can be a conventional one, such as a mixture of metallic aluminum and aluminum salts, and the dosage is also conventional. The fluorination product concentration tower 2 is provided with a condensation device according to the conventional setting. Specifically, a hydrogen fluoride inlet is arranged at the bottom of the fluorination reactor 1, a chloroform inlet is arranged at the upper part, and the top is connected to the fluorination product concentration tower 2 through a pipeline. The bottom of the fluorination product concentration tower 2 is connected to the bottom of the fluorination reactor 1 through a first reflux pipe 8, and the top is respectively connected to the chlorodifluoromethane product tank and the disproportionation reactor 3. A chloroform inlet is arranged at the upper part of the disproportionation reactor 3, and the top is connected to the lower part of the pre-concentration tower 5. The top of the pre-concentration tower 5 communicates with the disproportionation product concentration tower 4. The top of the disproportionation product concentration tower 4 is respectively connected to the hydrogen chloride recovery tank and the chlorodifluoromethane product tank.
[0016] In the reaction, the raw materials and products proceed in the device according to the following process:
[0017] The reactant chloroform is added through the chloroform inlet located at the upper part of the fluorination reactor 1, and hydrogen fluoride is added through the hydrogen fluoride inlet located at the bottom of the fluorination reactor 1. After the fluorination reaction, the product mixture enters the fluorinated product concentration tower 2 from the top of the fluorination reactor 1 through a pipeline and then enters from the bottom. Due to the boiling point differences of the components in the fluorinated product concentration tower 2, dichlorofluoromethane (boiling point 8.9 °C) is condensed and returns from the bottom of the fluorinated product concentration tower 2 to the fluorination reactor 1 through the first reflux pipe 8 at the bottom to participate in the fluorination reaction again; the product chlorodifluoromethane (boiling point -38.1 °C) enters the chlorodifluoromethane product tank from the top of the fluorinated product concentration tower 2 for refining. Trifluoromethane (boiling point -84 °C) and hydrogen chloride (boiling point -85 °C) with similar boiling points enter the disproportionation reactor 3 from the top of the fluorinated product concentration tower 2 through a pipeline and then enter from the bottom. In this disproportionation reactor 3, trifluoromethane undergoes a disproportionation reaction with chloroform. Chloroform is continuously added through the chloroform inlet, generating chlorodifluoromethane and dichlorofluoromethane. The mixed gas enters the pre-concentration tower 5 from the top of the disproportionation reactor 3 through a pipeline and then enters from the lower part. Under the cooling effect of the pre-cooler 7, dichlorofluoromethane is condensed and returns from the bottom of the pre-concentration tower 5 to the fluorination reactor 1 through the second reflux pipe 9 at the bottom to continue participating in the reaction. Chlorodifluoromethane and hydrogen chloride continue to rise to the disproportionation product concentration tower 4. Under the action of the top condenser 6, high-purity hydrogen chloride enters the hydrogen chloride recovery tank from the top for further recovery and utilization, and chlorodifluoromethane enters the chlorodifluoromethane product tank from the top as a product for refining.
[0018] The above process can be carried out continuously.
[0019] Even if not shown in the figure, the device of the present utility model includes conventional components, such as all pipelines including conventional valve components, each reaction vessel includes necessary pressure gauges, thermometers and other conventional instruments and meters, as well as some stirring devices, etc.
[0020] The flow rate of the -15 °C chilled brine in the top condenser 6 is 150 - 200 kg / h, and the top pressure of the disproportionation reactor 3 and the disproportionation product concentration tower 4 is about 1.5 MPa.
Claims
1. A fluorochloromethane production and separation device, comprising a fluorination reaction kettle (1) and a fluorination product concentration tower (2) connected to the fluorination reaction kettle (1), wherein the fluorination product concentration tower (2) is connected to a fluorochloromethane product tank, characterized in that: The fluorination product concentration tower (2) is also connected to the disproportionation reactor (3), and the disproportionation reactor (3) is connected to the disproportionation product concentration tower (4) via a pre-concentration tower (5), a pre-cooler (7) is arranged on the periphery of the pre-concentration tower (5), a top condenser (6) is arranged on the periphery of the top of the disproportionation product concentration tower (4), and the bottom of the pre-concentration tower (5) is connected to the fluorination reaction kettle (1) via a second reflux pipe (9).
2. The difluorochloromethane production and separation device according to claim 1, characterized in that: The bottom of the fluorination product concentration tower (2) is connected to the fluorination reaction kettle (1) via a first reflux pipe (8).
3. The difluorochloromethane production and separation device according to claim 1, characterized in that: The disproportionation reactor (3) is a tubular reactor, which is provided with a plurality of heating tubes (3.1).
4. The difluorochloromethane production and separation device according to claim 3, characterized in that: The heating tubes (3.1) are filled with chloroform, or chloroform and a catalyst.
5. The difluorochloromethane production and separation device according to claim 1, characterized in that: The tower top condenser (6) and the precooler (7) are both connected to a chilled brine system.