Method for producing 1,2-dichloroethane and the device for its implementation

 

(57) Abstract:

The invention relates to a method for producing 1,2-dichloroethane by reacting Athena with hydrogen chloride and oxygen or oxygen-containing gas on copper-containing catalyst in the fluidized bed. Hydrogen chloride and oxygen (educti) are injected directly into the fluidized bed through inlet pipes, made in the form of gas-permeable porous molded product. Aten and the flow of recycle gas is injected through the bottom made of a porous gas-permeable material or provided with a molded product of a porous gas-permeable material. The device for implementing the method has a reactor with a fluidized bed equipped with pipelines for input streams doctow and at least one pipe for removal of the reaction products. At least one of the pipes to enter doctow made of porous material, and the bottom, which is designed to enter Athena and flow of recycle gas, is made of a porous gas-permeable material or provided with a molded product of a porous gas-permeable material. This increases the yield of 1,2-dichloroethane. 2 S. and 9 C.p f-crystals, 1 Il.

Under oxychloination generally refers to the interaction of the alkene with hydrogen chloride and oxygen or oxygen-containing gas, such as air, with the formation of saturated chlorinated alkane. The reaction can be represented by the following equation on the example of the transformation of Athena in 1,2-dichloroethane (also known as ethylene dichloride or the abbreviation "ejh"):

C2H4+ 2HCl + 1/2O2<--- ---> Cl-CH2- CH2- Cl + H2O.

In one embodiment of this method, most often carried out in krupnoporistogo scale, use a fluidized bed of catalyst, which basically is a chloride of copper on aluminiumoxide media. In this catalyst layer separately from each other enter Aten and oxygen, respectively, of oxygen-containing gas, with hydrogen chloride is usually served in dosed quantities, together with oxygen, respectively, of oxygen-containing gas. Special attention is paid to ensure that the reagents have come in contact with the fluidized bed before between reaction occurs. Due to this it is possible to avoid the formation of explosive mixtures.

From DE-C 19505664 (AU-A 9528810) the known device and egeda separated from the rest of the space for fluidized catalyst, and in this reactor within a fluidized bed of the first gas supplying pipeline (distribution pipes with nozzles distributed throughout the cross section of the reactor. When this nozzle end of the tube opening from which the gas stream fed into the reactor mainly prototokos to the gas flow, which is used for fluidization of the catalyst. The space between the lower ends of these tubes and the upper ends of the tubes, which are sealed in the fence separating the fluidized catalyst from the rest of the reactor with a second gas-feeding pipe, forms a mixing zone, the dimensions of which are selected so that, first, the mixing of the reactants with the catalyst could be done in this area and that, secondly, tubes, and the lower fence had not been a strong mutual erosive effect.

In preferred embodiments perform this unit has tubes that pass through the fence separating the fluidized bed of catalyst, and in which below this fence, but above the lower ends of the tubes are located nozzle. These nozzles are further distinguished by the fact that they are the La lining to the upper ends of the tubes throughout the cross section of the corresponding tube. When this nozzle located at some distance from the tube, having at the lower end of a certain diameter, and the tube is made of such length that the velocity of the gas streams flowing down from the nozzle, could be aligned to the lower ends of the tubes throughout the cross section of the corresponding tube. In addition, the nozzles have different diameters, thus ensuring uniform distribution throughout the cross section of the reactor is supplied through the gas supplying pipeline gas quantity.

Ways for which used a similar device known from DE-U 9116161 and WO 94/19099 (ZA-A 9401086).

All these known methods are time-consuming, and used for their implementation devices have a complicated structure, because of which the introduction of a flow of gaseous doctow in the reactor is virtually impossible to control.

Based on the foregoing the present invention has been put to develop such a method, which would allow the greatest extent possible to facilitate the introduction of doctow in the reactor and at the same time would provide this introduction of doctow in fine form.

Thus, the object of the invention is Gerasim gas on copper-containing catalyst in the fluidized bed. This method is characterized in that at least one of the threads of doctow, which are hydrogen chloride and oxygen, are injected directly into the fluidized bed through inlet pipes, made in the form of gas-permeable porous molded product, and Aten and the flow of recycle gas is injected through the bottom made of a porous gas-permeable material or provided with a molded product of a porous gas-permeable material.

Therefore, according to the invention a supply of reagents, namely Athena, on the one hand, and oxygen (which should be comprehended as well as oxygen-containing gas), on the other, carried out in such a way as to introduce at least one of these reactants in a fluidized bed in finely dispersed form through the porous molded product. Hydrogen chloride in metered quantities to add in one or both of the reagent, respectively, be added to them.

Preferably and oxygen, on the one hand, and Aten, on the other hand, serve in a fluidized bed of catalyst in a highly dispersed form, and as indicated above, hydrogen chloride can be introduced in a fluidized bed together with one reagent or obojetnych candles or arranged in a row, for example in parallel, tubular elements made from porous materials. For this purpose, suitable, for example, glass or ceramic Frit, known from the field of laboratory equipment. It is preferable to use a thin porous items from sintered metals, which have a relevant chemical and thermal resistance. For this purpose you can use in chemical engineering materials, such as alloys based on iron brand VA or corrosion-resistant alloys, commercially available under the names ofINCONEL (trademark of Inco Ltd.; chromium-Nickel alloy),MONEL (trademark of Inco Ltd. ; copper-Nickel binary alloy),HASTELLOY (Nickel alloy). In that case, if the reagents required to submit a counter-current gas-feeding pipe is preferably equipped with a porous molded product within a fluidized bed so that the gas left in countercurrent to the gas flow introduced through the fence that defines the boundary of the fluidized bed from below. In the absence of the same in submission reagents countercurrent gas can then be applied in other directions, or in all directions.

Telescoop is about 50 μm, preferably from 5 to 20 μm.

Another important aspect of the invention is a specific embodiment of the fence for a fluidized bed, which according to the invention made in the form of a porous molded product. For this purpose, suitable, for example, glass or ceramic Frit, known from the field of laboratory equipment. It is preferable to use a thin porous items from sintered metals, which have a relevant chemical and thermal resistance. For this purpose you can use in chemical engineering materials, such as alloys based on iron brand VA or corrosion-resistant alloys, commercially available under the names ofINCONEL (trademark of Inco Ltd. ; Nickel-chromium alloys),MONEL (trademark of Inco Ltd.; copper-Nickel binary alloy),HASTELLOY (Nickel alloy).

The second object of the invention is a device for implementing the method (see the drawing), with the reactor 2 fluidized bed equipped with pipelines 1 and 3 for input streams doctow and at least one pipeline 5 for removal of the reaction products. This device differs in the additional embodiment of the device characterized by the presence of the filtering device 4 of the porous material, with the help of which the reaction products before they branch pipeline 5 are filtered.

In another preferred embodiment, the device is characterized in that the reactor 2 has a bottom 12, which is intended to enter Athena and flow of recycle gas and which is made of a porous gas-permeable material or provided with a molded product of a porous gas-permeable material.

The present invention has a number of advantages.

Elements of porous material provide for the introduction of gases in a fluidized bed of catalyst in the form of very small bubbles. While such gases are in the form of tiny bubbles, obviously, much easier to come into contact with the surface of the catalyst and therefore much faster to react with other components of the reaction. This ensures a much more effective control over the course of the reaction, which occurs with higher selectivity, i.e., reduces the formation of by-products, and the yield of the target product increases. In addition, the introduction of the gases in the form of tiny bubbles virtually eliminates the risk of yield of the reaction under control, which in turn dapayk more bubbles evenly distributed throughout the cross section of the reactor, that also improves the mass transfer. The introduction of the gases in the form of tiny bubbles can further significantly reduce the distance between the cooling elements in the fluidized bed, thereby significantly increasing the surface area of the cooling per unit volume in the reaction zone. This more intensive cooling, in turn, allows not only more effectively to control the course of the reaction, but also significantly reduce the volume of the reactor.

Another significant advantage is that the use in the proposed method, a gas-feeding device of porous material eliminates the possibility of penetration into such a porous material of high dispersion of the catalyst in the termination of supply of the gaseous components of the reaction. Thus there is no need in practice at the present time, the use of purge gas, for example nitrogen, which, when inhaled in significant quantities in the exhaust gases, significantly complicates the disposal of the latter.

The most compact design of the reactor for the oxychlorination process is achieved due to the fact that a significant portion of the catalyst is retained in the reactor through fine filtration, with special preimuschistva gas-permeable molded product can be performed in the form of filter candles, bag or cartridge filter. In the process of fine filtering delayed particles larger than 1 micron. Thus, it may no longer be necessary in the application required currently cyclones, delaying the catalyst particles.

Thanks to the uniform expiration of gaseous reactants is significantly reduced and catalyst losses as a result of abrasion. In the granulometric composition of the catalyst remains almost constant for a long period of time, which in turn contributes to a more uniform reaction. Besides the already mentioned advantages associated with improved selectivity and safety, significantly increases the service life of equipment and reduce costly periods of stops in the result of equipment failure and maintenance.

In the rest of the way oxychlorination process carried out in a known manner with the creation of the following conditions. The temperature in the reaction zone of the reactor is maintained within the range of from 200 to 270oC, preferably from 215 to 230oC, particularly preferably from 220 to 225oC. Install the pressure (excess) is 2,>to 3,5105PA. On one mol of Athena varies from 1.5 to 2.5 mol, preferably from 1.8 to 2.1 mol of hydrogen chloride and from 0.2 to 0.9 mole, preferably from 0.4 to 0.7 mole of oxygen, and, as is known, particular attention should be paid to Aten, respectively, the oxygen before entering into interaction with another reagent first came into contact with the catalyst, as, for example, described in DE-C 19505664.

An alternative to this it is possible to work on other known technologies in order to avoid formation of explosive gas mixtures.

Recycling the gaseous reaction product is carried out also in a known manner. You can refer to, for example, specified in the beginning of the description of the publication, sections are devoted to such processing should be considered as part of the present description.

Below the invention is explained in more detail by the example of its implementation. Specified position in parentheses refer to the accompanying description of the drawing.

Example

Hydrogen chloride with consumption 5910 nm3/h (where nm3means the amount in m3in normal conditions) and a temperature of 150oC and oxygen with a flow rate of 1600 nm3/h with the temperature of the metal elements 11 in the reactor 2, namely, directly into the lower part of the fluidized bed. Eaten with a flow rate of 3000 nm3/h together with recycle gas was heated to 150oC and line 3 is fed into the reactor 2. This enriched Atena recycle gas was introduced through the bottom 12, equipped with a molded product made of porous sintered metal. In the reactor 2 was 40 tons of fluidized catalyst (alumina with a copper content of 4 wt.%) the following particle size distribution:

The particle size, microns - Share (sifting), wt.%

< 20 - 4

< a 32 - 6

< 41 - 26

< 50 - 54

< 61 - 82

< 82 - 96

The heat of reaction were taken through the circulation loop hot water steam. The gaseous reaction product after exiting the fluidized bed was passed with the aim of separating entrained by the gas flow of catalyst particles through located in the upper part of the reactor filter 4 ultrafine cleaning, which is almost completely arrested the catalyst particles. Then not containing catalyst, the gaseous reaction product to a temperature of 220oC was supplied by a pipe 5 into the cooling column 6, where there was condensation process water, which is then in line 7 took to the stage is 0.05 mg/L. Taken from the head of the column a stream, consisting mainly of ejh and recycle gas, was supplied by a pipe 8 to the stage of processing ejh.

Filter 4 hyperfine clean regenerates by creating a differential pressure supplied through pipe 9 of nitrogen, which was heated to 180oC in the apparatus 10 for pre-heating. The degree of particulate catalyst amounted to more than 99.99%. After three months of operation has not been established any significant changes in particle size distribution of fluidized catalyst.

1. Method for producing 1,2-dichloroethane by reacting Athena with hydrogen chloride and oxygen or oxygen-containing gas on copper-containing catalyst in the fluidized bed, characterized in that at least one of the threads of doctow, which are hydrogen chloride and oxygen, are injected directly into the fluidized bed through inlet pipes, made in the form of gas-permeable porous molded product, and Aten and the flow of recycle gas is injected through the bottom made of a porous gas-permeable material or provided with a molded product made of a porous or gas-permeable ceramics.

3. The method according to p. 1, wherein the porous molded product made of sintered metal.

4. The method according to any of paragraphs.1-3, characterized in that the porous molded products have a pore diameter of 0.5-50 μm.

5. The method according to any of paragraphs.1-4, characterized in that the supply of gas in the reactor can be carried out through the porous molded product in all directions.

6. The method according to any of paragraphs.1-5, characterized in that is carried out of the fluidized bed of the catalyst is almost completely arrested in the reactor, catching it with the fine filter is made in the form of a gas-permeable porous molded product.

7. The method according to any of paragraphs.1-6, characterized in that by using fine filtration retain particles larger than 1 micron.

8. The method according to any of paragraphs.1-7, characterized in that a thin filtering is carried out with the help of filter cartridges, bag or cartridge filters.

9. The method according to any of paragraphs.1-8, characterized in that the used filter candles made of sintered metal or ceramic.

10. The device for implementing the method according to any one of paragraphs.1-9, having a reactor with a fluidized bed equipped ttlichen fact, that at least one of the pipes to enter doctow made of porous material, and the bottom, which is designed to enter Athena and flow of recycle gas, is made of a porous gas-permeable material or provided with a molded product of a porous gas-permeable material.

11. The device according to p. 10, characterized by the presence of the filtering device of porous material through which the reaction products before they branch pipelines are filtered.

 

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