The method of dehydrogenation of alkylaromatic hydrocarbons in alkenylamine hydrocarbon, the method of regeneration and stabilization of the activity of iron oxide catalyst and install the dehydrogenation of alkylaromatic hydrocarbons

 

(57) Abstract:

The method of dehydrogenation of alkylaromatic hydrocarbons in alkenylamine hydrocarbon in the presence of water vapor and iron oxide catalyst, activated alkali metal at elevated temperature in the reactor is characterized by the fact that after an initial period of use of the catalyst for a duration of 3 to 45 days to form a mixed stream of reagents consisting of alkylaromatics hydrocarbon, steam, and compounds of alkali metal, in an amount equivalent to from 0.01 to 100 hours per million by weight of compounds of alkali metal relative to the total weight alkylaromatic hydrocarbon and steam, and continuously add-formed stream in the reactor, the number of connections alkali metal sufficient to maintain a mostly constant degree of conversion of alkylaromatic hydrocarbon and selectivity get alkanolamides hydrocarbon. Describes the installation for the above process. The technical result is a significant increase in service life of catalyst used in catalytic dehydrogenization alkylaromatic hydrocarbons, while ensuring. C. and 59 C.p. f-crystals, 3 ill., table 4.

The present invention relates to a method and corresponding installation for a substantial increase in service life of the layer of catalyst used in catalytic dehydrogenization alkylaromatic hydrocarbons, while providing a high degree of conversion and high selectivity without the need to interrupt the process of transformation.

Art

It is known that alkylaromatics hydrocarbon can be catalytically digidrirovanny education alkanolamides hydrocarbon, an example is the conversion of ethylbenzene to styrene. From the previous prior art a number of different catalysts for dehydrogenation and process parameters, and they all have different advantages and disadvantages. In General from the previous prior art it is known that some compromises usually have to be made between degree of conversion and selectivity between degree of conversion and life of the catalyst and so on. For example, the lack of a higher degree of dehydrogenation of alkylaromatic compounds in some of the processes may be lower selectivity, i.e. a higher content Ni is to achieve as high degrees of conversion, and high selectivity, if possible.

The service life of the catalyst and the associated cost factors are another important indicator of the processes of dehydrogenation. First are the costs associated with the catalyst. Although the cost per unit of catalyst may not be significant, due to the required large amounts of catalyst, as well as costs for disposal of used, contaminated catalyst acceptable environmental manner, the service life of the catalyst and the ability to regenerierung used catalyst are crucial in the industrial process of dehydrogenation. Second are the costs associated with stopping a large, possibly multi-stage dehydrogenation reactor operating at temperatures of the order of 600oC, for the purpose of replacement or regeneration of the catalyst. In addition to the obvious costs for payment of the labour force have also place capital costs due to the lack of expensive equipment for a fairly long time. Heat loss add additional expenses for replacement of the catalyst or its regeneration. Even more important is the cost of unreleased products in time service of the catalyst. However, on the other hand, natural poisoning of the catalyst in the process leads to a decrease in the degree of conversion, selectivity, or both, resulting in undesirable loss of efficiency of the process. In the literature there are various possible explanations typical of poisoning of catalysts for the dehydrogenation using. They include the carbonization catalyst surface, the physical destruction of the structure of the catalysts, loss of activators of catalysis and so on. Depending on the catalyst and on the various parameters of the process can operate one or more of these mechanisms, or other, as yet unidentified mechanisms.

Although the technique described various methods of regeneration of used catalyst for temporary and only partial recovery of the catalyst efficiency, these methods usually entail stop dehydrogenation, disabling the dehydrogenation reactor or, in some cases, removal of the catalyst for regeneration elsewhere. In addition, the impact on the process of such periodic regeneration of the catalyst leads to unwanted sawtooth nature of the quality change issue is about deteriorate until when the catalyst regenerate to restore a relatively high degree of conversion and selectivity. However, immediately after this, the catalyst efficiency starts to deteriorate. As a result, it is impossible to use traditional methods of regeneration of the catalyst to achieve a substantially stable process conditions with a high degree of conversion and selectivity.

For example, in the descriptions to the German patent N DD 298353, DD 298354, DD 298355, DD 298356 and DD 298357 described 3-stage regeneration process of the catalytic layer in the dehydrogenation of ethylbenzene to styrene, comprising: (1) stop the reaction and the replacement of the steam flow in the mixing flow of steam and ethylbenzene; (2) a subsequent step of heat treatment, and (3) the subsequent introduction of potassium ions in the input pairs (for example, by evaporation KOH or K2CO3). None of these patents, however, is not described and not offered by the regeneration of the catalyst in situ without interrupting the process. The process according to this German patent would be costly, burdensome and would result in obtaining the above-mentioned junk model with a sawtooth changing the quality of the final product.

Thus, in the prior art no description the implementing conditions of the dehydrogenation, for a long time and at very high degrees of conversion and selectivity, without interrupting the process. These and other problems and limitations of the prior art are overcome by using method of regeneration and/or stabilization of the catalyst and installation for these purposes according to this invention.

The invention

In line with this, the main purpose of this invention is to provide a method and installation for regeneration and/or stabilization of the dehydrogenation catalyst.

Another purpose of this invention is to provide a method and installation for regeneration in situ catalyst dehydrogenation.

Another particular object of this invention is to provide a method and installation for continuous or periodic regeneration of the dehydrogenation catalyst without interrupting the process and, thus, to maintain a practically stable reaction conditions with a high degree of conversion and selectivity over a long period of time.

Another purpose of this invention is to provide an improved method for the dehydrogenation of ethylbenzene to styrene in the presence of a catalyst containing iron and the connections of the method and the installation for regeneration and/or stabilization of the dehydrogenation catalyst, containing iron and one or more compounds of alkali metals, by almost continuous (i.e. continuous or periodic) adding a compound of an alkali metal in the feed stream.

Other objectives of this invention will be partly apparent and partly revealed below. In accordance with this invention comprises methods, processes and installation embodying these several steps and the relation and order of one or more of these stages in relation to one another and to install, illustrated by examples in the following detailed description of the invention and the scope of which will be indicated in the claims.

The method of regeneration and/or stabilization of the dehydrogenation catalyst according to this invention includes a stage is practically constant, either continuous or intermittent added to the original thread reagents, compounds of alkali metal during the process of dehydrogenation. The method according to the invention can also include a stage of gradually increasing the temperature in the reaction zone. The method according to this invention can be used, for example, when the catalytic dehydrogenation of ethylbenzene in particular the P CLASS="ptx2">

List of figures, drawings and other materials.

Fig. 1 schematic illustration of one possible implementation of the method and installation according to the invention.

Fig. 2 illustrates a preferred method and corresponding device for adding a compound of an alkali metal according to this invention.

Fig. 3 illustrates an alternative method and corresponding device for implementing the step of adding the compound of the alkali metal according to this invention.

Information confirming the possibility of carrying out the invention

The method according to this invention broadly involves the regeneration and/or stabilizing the activity of the dehydrogenation catalyst used in the catalytic dehydrogenation of alkylaromatic hydrocarbons to obtain a specific desired alkanolamides hydrocarbon. Such dehydrogenation catalysts are well known in this area and are available on the market. In General, such processes are catalytic dehydrogenation is carried out at temperatures in the range from approximately 400oC to about 700oC and preferably in the range from approximately 500oC to 700the static hydrocarbon and steam, with a specific catalyst for the dehydrogenation. This process can be carried out in a single stage or multi-stage reactor having a fixed layers of the catalyst or catalysts in the fluidized bed. Select the source of alkylaromatic hydrocarbons, the dehydrogenation catalyst, the reaction temperature and the proportions of the alkylaromatic hydrocarbon to steam in the feed stream will be partially affect the resulting alkenylamine hydrocarbons, as well as on the efficiency and selectivity of the conversion process.

In particular, when applying the above process, the ethylbenzene is converted into styrene in contact with a dehydrogenation catalyst containing iron and at least one compound of an alkali metal. For example, the conversion of ethylbenzene to styrene can be advantageously carried out at reaction temperatures ranging from approximately 500oC to 700oC, preferably from about 550oC to 650oC, and at pressures of reaction in the range of from about 3 to 20 abs. psig (0.2 to 1.4 kg/cm2), preferably from about 5 to about 9 abs.psig (0.35 to 0.63 kg/cm2). The ratio of steam to hydrocarbon in the feed stream of the reagent will be skorosti can be in the range of 0.2 to 1.2 kg of ethylbenzene per hour per kilogram of catalyst.

At the beginning of the process of conversion of ethylbenzene to styrene in the fresh catalyst after starting is usually the initial period of entry mode, which lasts from about 3 to 45 days and is characterized by a high initial activity followed by a rapid decline in activity. For example, during the initial period in accordance with the standards of the average degree of conversion of ethylbenzene to styrene may fall below 55 mol.%, and the level of selectivity to styrene may fall below 93 mol.%. Then in the normal processes of dehydrogenation of ethylbenzene to styrene, the catalyst activity continues to fall, albeit more slowly than in the initial period. In multi-stage reactor, the level of conversion of ethylbenzene to styrene at each level may fall by about one third, for example, from 30-36 mol.% up to 20-24 mol.%, during the initial period in accordance with the regulations, and then continues to fall more slowly. The end of the initial period in this process, the specialists usually defined as the point at which the curve of the graph according to the degree of conversion from time out on the plateau. As noted above, in the prior art suggested a number of possible explanations for the gradual reduction in the activity of CA is in no matter the explanation, continuing deterioration of the process after the initial period in accordance with the regulations leads to a number of problems and drawbacks. First, it reduces the efficiency of the process of transformation. Unreacted ethylbenzene must be separated from other components of the exit stream for return to the cycle. Styrene should be similarly separated from unreacted ethylbenzene, as well as from other reaction products. Secondly, instead of a relatively uniform output flow having a relatively constant ratio of styrene, ethylbenzene and mixed by-products, the deterioration process results in the exit stream with a constantly changing composition. Thirdly, at some point the level of transformation or the level of selectivity to styrene or both together fall low enough, resulting in this process is not economically viable. At this point, the process should be stopped, and the catalyst must either be replaced or subjected to regeneration by conventional means.

One method of maintaining the level of conversion of ethylbenzene to styrene is to increase the reaction temperature. This can be accomplished, for example, by increasing the flow temperature reactions constantly, or it can be increased periodically increments. The impact of such increases the reaction temperature is to increase the rate of reaction in order to eliminate the continued deterioration of catalyst activity. However, there are relatively narrow limits the usefulness of this technique of increasing temperature. In particular, videopreteen temperature approaching the mechanical limit temperature of the catalyst or equipment. After this point, further increase in the temperature leads to the destruction of the physical structure of the catalyst and to the degradation of the integrity of the equipment. So as it approaches the above limit, the process must be stopped and the catalyst was either replaced, or shall be subjected to regeneration by conventional means. Although this method of increasing the temperature extends in some degree the life of the catalyst and can be used (for example, by continuous or small, frequent increases in the reaction temperature) to maintain a relatively constant conversion of ethylbenzene for a limited period of time, by itself it is of limited usefulness for these reasons.

On the contrary, the method according to this invention is of Aligator much longer, that can be achieved using conventional processes. More specifically, the method according to this invention is capable of restoring the activity of a dehydrogenation catalyst to almost the same high levels of conversion and selectivity, which are installed at the end of the initial period standard terms and conditions. The method according to this invention is also capable of stabilizing the active catalyst on the same high levels of conversion and selectivity over a long period of time greater than the time provided by conventional processes. The method according to the invention can also be used in conjunction with the above method of increasing the temperature to achieve additional benefits from further increases the service life of the catalyst or by increasing the conversion of ethylbenzene. The method according to this invention broadly includes the steps of continuous or intermittent added to the feed stream of reagent alkylaromatic hydrocarbon an effective amount of a compound of an alkali metal, sufficient for recovery, stabilization or strengthening the activity of the dehydrogenation catalyst and, thus, for vosstanovlyennom case, shall be construed to mean "to keep in a state of repair, efficiency, or effectiveness; to protect from damage for a long period of time, for example, for many months or years." This method has particular utility in connection with the regeneration and/or stabilization of the dehydrogenation catalyst containing iron and at least one compound of alkali metals. Such dehydrogenation catalysts are well known in the art, and some of those on the market include: brand S6-20, S6-21 and S6-30 from the company BASF; brand C-105, C-015 C-025 C-035 from the firm Criterion catalyst company; and brand G-64 G-84 (including catalyst G-84C applied in the following Examples 1-4) from the company United Catalysts. These catalysts typically contain 40-80% Fe2O3, 5-30% K2O, and other activators. All of them, and such catalysts are considered as being within the scope of this invention.

The method according to this invention can be used in the catalytic dehydrogenation of virtually any alkylaromatic hydrocarbon to the corresponding alkanolamine hydrocarbon. The appropriate combination of alkylaromatics what about the hydrocarbon in General is well known in the art and, in any case, would become a matter of choice and routine experiment. The method according to this invention has particular utility in connection with the regeneration and/or stabilization of the dehydrogenation catalyst in the conversion of ethylbenzene to styrene.

Fig. 1 is a block diagram that schematically illustrates one variant of the method according to this invention, in which the connection of the alkali metal type in the input stream of raw materials, as well as partially into the flow of the reagent, passing between the stages of the multistage reactor. Although for purposes of discussion of Fig. 1 the expression "the incoming flow of raw materials and partially into the flow of reagents are used to help identify the specific stage of the process of transformation, throughout this description, these terms are treated as common and interchangeable. In Fig. 1 the incoming flow of raw material 1 can be a supply of alkylaromatic hydrocarbons, such as ethylbenzene, and an input stream 2 may be steam. As shown in Fig. 1, an effective amount of a compound of an alkali metal is added continuously, that is, either continuous or intermittent manner, in the feed stream 2 is sterile in the flow of raw material 1. The feed streams 1 and 2, including any connection alkali metal, are connected in the flow of reagent 3 and go to the entrance to the first stage reactor 50, which is loaded with a suitable dehydrogenation catalyst. Alternatively, the compound of the alkali metal may be added after the input streams 1 and 2 will be merged into the stream of reagent 3 to the first stage 50 of the reactor. Partial conversion of alkylaromatic hydrocarbons, such as ethylbenzene to styrene occurs in stage 50 of the reactor.

Partially into the flow of reagent or output stream 4, the output from stage 50 of the reactor, and then passed through a heater 52 for recovery of heat losses on level 50 of the reactor and to restore the optimal reaction temperature. Additional connection of the alkali metal of the tool 66 filing of an alkali metal serves constantly, either continuously or intermittent manner, in a partially into the flow of reagent 5, coming out of the heater 52, before the flow of reagent 5 is directed to the input of the second stage reactor 54. Alternatively, an additional connection of the alkali metal may be added in a partially into the flow of reagent 4 with a suitable dehydrogenation catalyst. Further conversion of alkylaromatic hydrocarbons occurs in step 54 of the reactor. Specialists in the art will be apparent that additional stage reactor downstream, such as the third or fourth step, each of which is loaded when a suitable catalyst, can be used to obtain greater conversion of alkylaromatic hydrocarbons. The addition compounds of an alkali metal in a stream of reagent in accordance with the method of the present invention, it is advisable to use between several or all stages of the multistage reactor in the reactor.

As shown in Fig. 1, the installation according to the invention in an appropriate case, may include control means for monitoring the chemical composition of output streams coming from the outputs of any or several stages of the reactor, such as control means 42 and 62, respectively associated with the flow of reagent 4 and 6. Controls in the appropriate case can also be connected to the means of actuation, such as electrical conductors 44 and 64, respectively, for alarm and actuation means of making compounds of an alkali metal, is oseney to consider the stage of the reactor, in particular, steps 50 and 54, respectively.

Controls can be adjusted using conventional technology to send signal on the money supply connection of an alkali metal in any case, when output from a given level of the reactor falls below a predetermined level of conversion or selectivity, which indicates the degradation activity of the catalyst at this stage of the reactor. After actuation by the signal from the involved controls money supply connection alkali metal begin to serve the connection of an alkali metal with a preset flow in the respective flow of raw materials or the flow of reagent. For example, on a signal from the control means 42 that the conversion or selectivity of the first stage reactor 50 has fallen below a certain level, the pump means 46 will be begin feeding connection of the alkali metal in the flow of raw material 2. The apparatus may be designed for actuation to continue submitting compounds of alkali metal within a predetermined period of time or until another signal from the involved controls will not report that the activity of the catalyst in rassmatrivaetsi automated system intermittent adding, as described above, also in the framework of the present invention will be constantly adding predetermined amounts of the compounds of the alkali metal in the respective flows of raw materials or reagent, or, alternatively, adding a compound of an alkali metal in predetermined quantities and pre-established intervals. It can be combined with continuous or intermittent monitoring of one or more streams output from the steps of the reactor. For signs of degradation of the catalyst at any stage of the reactor, can be manually powered means of increasing the addition compounds of alkali metal in the flow of raw materials or in the flow of the reagent, upstream with respect to the given stage of the reactor. Increased consumption of added compounds of the alkali metal can be enabled for a limited period of time to restore the desired level of catalyst activity or may also be supported by a new, increased consumption.

In Fig. 2 schematically illustrates in more detail one preferred method and corresponding device for adding a compound of an alkali metal in the flow of raw materials or in the flow of the reagent in sootle reactor, containing a dehydrogenation catalyst, as illustrated by the arrows. Stream 12 may represent, for example, flows of raw materials 1 or 2, the flow of the combined reagent 3 or partially into the flow of reagent 4 and 5, as shown in Fig. 1. The connection of the alkali metal added constantly, either continuously or intermittently, in stream 12 in the form of an aqueous solution 22 which is inserted through the injection tool 24 at the outlet end of the injection tube 20, built through the hole in the wall of the pipeline 10. Stream 14 that is located downstream relative to the outlet end of the injection tube 20 is a flow of raw materials or the flow of the reagent, which was mixed with the compound of the alkali metal in accordance with this invention.

In Fig.3 schematically illustrates an alternative method and corresponding device for adding a compound of an alkali metal in the flow of raw materials or in the flow of the reagent according to this invention. The pipeline 10 of Fig. 3 contains and directs the flow 12 in the direction of the stage reactor containing a dehydrogenation catalyst, as shown by arrows 12 and 14. Stream 12 may represent, for example, flows of raw materials 1 or 2, the combined stream of reagent 3 or OSD 30, openly reported on a couple of channel flow stream 12 and is able to contain solid or liquid substance. The connection of the alkali metal in the solid or liquid state is supplied, when required, in the inner part 34 of the receptacle 30 through the input means 32, in order to gradually evaporate and diffuse into the passing flow, as shown by the arrows inside the vessel 30. Stream 14 that is located downstream relative to the vessel 30 is a flow of raw materials or the flow of the reagent, which was previously mixed with the compound of the alkali metal according to this invention.

Compounds of the alkali metal that is suitable for implementing the method according to this invention include all smoke zero halogen sources of alkali metal ions. In the case of use in this invention, the term "alkali metal" is understood as including, but not limited to this, potassium, sodium, lithium, and other less common metals of group IA of the Periodic table of elements, such as rubidium and cesium. However, cost considerations will usually dictate the choice of potassium or sodium compounds. For some applications can also be useful metals of group IIA of the Periodic table (which I as a matter of routine experiment. In connection with dehydrogenization of ethylbenzene to styrene, the preferred compounds of alkali metals are potassium compounds, more specifically one or more selected from the group consisting of potassium oxide, potassium hydroxide and potassium carbonate. Also within this invention is the use of mixtures of two or more compounds of an alkali metal. Due to the fact that ions of Halogens, such as chloride, as usual it was discovered that poison the catalyst dehydrogenation, usually it is necessary to avoid such compounds of alkali metals, such as potassium chloride.

The number of connections of an alkali metal, which should be added to the flow of raw materials or in the flow of the reagent according to this invention, may vary depending on the catalyst, the alkyl-aromatic hydrocarbon, the reaction conditions and the compounds of the alkali metal. The effective amount or effective flow when the connection is added to the alkali metal in the flow of reagent is sufficient to maintain high levels of conversion and selectivity can be determined by routine experimentation to optimize the system performance. In General, it was found that the effective number of connections alkaline meeka reagent, preferably from about 0.10 to about 10 weight parts, the average for a characteristic period of time. The typical period of time, as it is used here, means the period of time during which high levels of conversion and selectivity without further adding a compound of an alkali metal. Also in the framework of the present invention is the change in the number of connections of the alkali metal in the flow of the reagent in the flow of time to restore or maintain optimal system performance.

The connection of the alkali metal may be added to the stream of reagent either continuously or intermittently and, in the case of intermittent supply, with regular or irregular intervals. Depending on what is added to the compound of alkaline metal is continuously or intermittently added amount, and, in the case of additions interruptibly selected intervals, must be such as to allow for the addition of an effective amount, sufficient to restore or maintain the required high levels of conversion and selectivity. In General, such amount will include from about 0.01 to about 100 parts by weight of compound y="ptx2">

The addition compounds of an alkali metal to the flow of the reagent can be performed in several ways. One such way of adding comprises adding a compound of an alkali metal in a dry, solid, powder form in a stream of reagent. Alternatively, a solid piece of compounds of the alkaline metal or the vessel containing this compound in solid, liquid form or in the form of a solution may be placed in the path of the heated stream of reagent, and he can gradually evaporate into the flowing stream, as shown in Fig.3. Another and particularly preferred method of addition is to add compounds of the alkali metal in the form of an aqueous solution into a stream of reagent, for example, as described above with respect to Fig.2. Because of the ease of implementation and the ability to automate this process, as described in connection with Fig. 1, the connection is added to the alkali metal in the form of an aqueous solution, apparently, should be in the normal case, the preferred commercial application of this invention. Another method consists in adding the injection compound of an alkali metal in liquid form into a stream of reagent. Another way to add is to pre-evaporation of compounds of alkali metal is naten when reading the following examples and test data, which are only illustrative and do not limit the scope or practice of the present invention.

Example 1

Steam and ethylbenzene in a molar ratio of 12 to 1 and with a flow rate of 825 grams/hour were introduced into the reactor, made of odnogolosy stainless steel pipe type 40, and heated in 8-zone electric furnace. In the reactor in four sections were loaded only 390 grams of catalyst, designated G-84C and manufactured by the company United Catalysts. The reactor was loaded with an inert balls of alumina on top of the first zone catalyst zones between the catalyst and under the fourth area. The reaction mixture was admitted into the reactor at a temperature of 250oC and it was preliminarily heated up to 598oC, when it was part of the first section of the catalyst. The average temperature of all four catalytic sections maintained with an accuracy of 1oC 594oC. At the reactor outlet was supported by the atmospheric pressure. Deactivation of the catalyst was noted between 854 and 1298 clock time of transmission of the stream, as shown in table 1. The selectivity to styrene was slightly increased during this period due to the reduction of the conversion of ethylbenzene. At 1310 hours of the test installation was stopped, and the container from the reactor a small amount of KOH is continuously evaporated and introduced into contact with the catalyst through fed to the reactor thread. The temperature in the container was controlled, resulting in a vapor pressure KOH was equivalent to about 5 parts per million (by weight) of the total supply. As it was found that the activity and selectivity of the catalyst was constantly improved between 1310 and 1500 hours. Then the catalyst activity remained stable for approximately 2.3 percent higher conversion and about 0.3 percent higher selectivity to styrene than before adding KOH. At 1642 hours, the conversion of ethylbenzene with the addition of KOH was 4.4 percent higher than what would be at the same time in the stream, if the catalyst was deaktivirovana with the same speed as before the addition of KOH. The selectivity for styrene with addition of KOH was 4.0 percent higher than the selectivity without KOH, compared with the data in the comparative conversion of ethylbenzene (for example, data on 854 hour).

Example 2

In the second reactor, completed, and uploaded similar to that described in example 1, was loaded with 32.5 grams of catalyst G-84C in the upper zone. The reactor was operating at an average temperature ranging from 594 to 612oC, the ratio of steam to ethylbenzene in the range of 9 to 12 and the outlet pressure (14.7 abs. psi (1.1 kg/cm2between 0 and 3341 hours. Rare in the upper zone was noted between 1722 and 1888 clock, as shown in the table. 2, while in this area supported the accuracy of the 1oC at 597oC. the Ratio of steam to ethylbenzene was 12 molar. On 3341 hour installation was stopped, and upstream with respect to the entrance of the reactor was set superheater, which allows you to download inside of KOH in the future without interrupting the reaction. After restarting the installation of the catalyst in the upper zone continued to be decontaminated while maintaining the accuracy in the 1oC at 622oC.

The ratio of steam to ethylbenzene was 9, and the outlet pressure of the reactor was 14.7 abs. psi (1.1 kg/cm2). When 3481 hour in the superheater downloaded to 7.0 grams KOH brand ACS without interrupting the reaction. The temperature of the superheater regulated to allow small amounts of KOH continuously evaporate and be in contact with the catalyst through the reaction mixture. The vapor pressure of KOH at this temperature was equivalent to about 9 parts per million (by weight) of the entire load. The conversion of ethylbenzene in the upper zone was rapidly improved from 5.1% to 12.3% for 103 hours while maintaining this zone accuracy in the 1oC at 622oC, and then gradually increased to 12.9% for 176 hours and remained pic is edstone is in contact with the flow of raw materials, the most exposed to decontamination, and had received the greatest benefit from the method according to this invention.

Example 3

The reactor described in example 2, worked to exhaustion KOH in the superheater. Then the outlet pressure and the ratio of steam to ethylbenzene was regulated to 6 abs.pounds per square inch (0.42 kg/cm2) and the molar 8:1, respectively. The temperature in the upper zone was maintained with an accuracy of 1oC at 622oC. Aging the upper zone of the catalyst was noted within 4731 up 5022 hours, while the selectivity for styrene gradually deteriorated. On 5022 hours in the superheater download advanced 1,90 grams of KOH, and the temperature of the superheater regulated so as to create a vapor pressure of KOH equivalent to about 2 ppm (weight) of the total raw materials. The transformation in the upper zone came from 9.2% to 11.4% for 24 hours and then stabilized approximately 11.0% for a long period of time, while the selectivity to styrene in the upper zone improved to 94.8 up to 96.8%, as shown in the table. 3.

Example 4

In example 3, the average temperature of all four zones of the catalyst was maintained with an accuracy of 1oC at 613oC. the Pressure at the outlet of the reactor was 6 abs. pounds the elk with 70,4% to 69.3% between 4728 and 5019 hour before loading the second portion KOH. The total selectivity to styrene was stable by 96.9%. After KOH was loaded into the superheater at 5022 hour, the total transformation steadily increased from 69.3 to 70,4% in two days and remained in subsequent above this high level. The selectivity for styrene remained stable at 96.9 percent in this period, i.e., the same selectivity was observed when a higher degree of conversion, as shown in the table. 4.

The above examples illustrate that the method according to this invention is effective in restoring the activity of a partially deactivated catalyst and stabilize the conversion of ethylbenzene to styrene in a high degree, while maintaining or improving the selectivity to styrene.

Since certain changes may be made in the above setup and methods without departing from the scope of the invention considered here, it is understood that all the material contained in the above description should be considered illustrative and non-restrictive.

1. The method of dehydrogenation of alkylaromatic hydrocarbons in alkenylamine hydrocarbon in the presence of water vapor and iron oxide catalyst, Akti the initial period of use of the catalyst with duration of 3 - 45 days form a mixed stream of reagents consisting of alkylaromatics hydrocarbon, steam, and compounds of alkali metal, and continuously add-formed stream in the reactor, the compound of alkaline metal is used in an amount equivalent to from 0.01 to 100 ppm by weight of compounds of alkali metal relative to the total weight alkylaromatic hydrocarbon and steam and sufficient to maintain a mostly constant degree of conversion of alkylaromatic hydrocarbon and selectivity get alkanolamides hydrocarbon.

2. The method according to p. 1, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenylamine hydrocarbon is a styrene.

3. The method according to p. 1, characterized in that the compound of the alkali metal is a compound of potassium or sodium.

4. The method according to p. 3, characterized in that the compound of sodium or potassium are selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium oxide, potassium oxide, sodium carbonate, potassium carbonate and mixtures thereof.

5. The method according to p. 1, characterized in that the compound of the alkali metal is GoM, solid, powder form.

7. The method according to p. 1, characterized in that the compound of the alkali metal in the solid or liquid state is injected into the stream of initial reactant entering the reactor.

8. The method according to p. 1, characterized in that the compound of the alkali metal is added in aqueous solution.

9. The method according to p. 1, characterized in that the compound of the alkali metal is added in the form of steam.

10. The method according to p. 1, characterized in that the compound of the alkali metal is added in liquid form.

11. The method according to p. 1, characterized in that the contact between the said mixed stream and a catalyst for the dehydrogenation is carried out at practically constant temperature of reaction.

12. The method according to p. 1, characterized in that it further includes a step periodic increase of the reaction temperature.

13. The method according to p. 1, characterized in that the catalyst consists essentially of 40 to 80% Fe2O3and 5 - 30% K2O.

14. The method according to p. 13, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenylamine hydrocarbon is a styrene.

15. The method according to p. 13, characterized in that the connection SEL the connection of sodium or potassium is chosen from the group consisting of sodium hydroxide, potassium hydroxide, sodium oxide, potassium oxide, sodium carbonate, potassium carbonate and mixtures thereof.

17. The method according to p. 13, characterized in that the compound of the alkali metal is potassium hydroxide.

18. The method according to p. 13, characterized in that the compound of the alkali metal is added in a dry, solid form.

19. The method according to p. 13, characterized in that the compound of the alkali metal in the solid or liquid state is injected into the stream of initial reactant entering the reactor.

20. The method according to p. 13, characterized in that the compound of the alkali metal is added in the form of an aqueous solution.

21. The method according to p. 13, characterized in that the compound of the alkali metal is added in the form of steam.

22. The method according to p. 13, characterized in that the compound of the alkali metal is added in liquid form.

23. The method according to p. 13, characterized in that the contact between the mixed stream and a catalyst for the dehydrogenation is carried out at practically constant temperature of reaction.

24. The method according to p. 13, characterized in that it further includes a step periodic increase of the reaction temperature.

25. The method according to p. 1, characterized in that CTLA receiving the second source stream of steam and compounds of an alkali metal, and the second source stream is combined with the third source stream, consisting mainly of alkylaromatic hydrocarbons, for receiving the mixed flow of the reactants.

26. The method according to p. 25, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenyl - aromatic hydrocarbon is a styrene.

27. The method according to p. 25, characterized in that the compound of the alkali metal is a compound of potassium or sodium.

28. The method according to p. 1, characterized in that the compound of the alkali metal added to the first source stream, consisting mainly of alkylaromatic hydrocarbons, for receiving the second source stream of the alkylaromatic hydrocarbon and a compound of an alkali metal, and the second source stream is combined with the third source stream, consisting mainly of a pair, for receiving the mixed flow of the reactants.

29. The method according to p. 28, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenylamine hydrocarbon is a styrene.

30. The method according to p. 28, characterized in that the compound of the alkali metal is a compound of potassium or not, consisting mainly of alkylaromatic hydrocarbon and steam, to obtain a mixed flow of the reactants.

32. The method according to p. 31, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenylamine hydrocarbon is a styrene.

33. The method according to p. 31, characterized in that the compound of the alkali metal is a compound of potassium or sodium.

34. The method according to p. 1, characterized in that the mixed flow of the reactants to form a multi-stage reactor, the compound of the alkali metal is introduced into the interstage flow reactor comprising alkylaromatic hydrocarbon, steam, and products of the dehydrogenation.

35. The method according to p. 34, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenylamine hydrocarbon is a styrene.

36. The method according to p. 34, characterized in that the compound of the alkali metal is a compound of potassium or sodium.

37. The method of regeneration and stabilization of the activity of iron oxide catalyst activated alkaline metal and used in the process of dehydrogenation reactor alkylaromatic ug is the solution of the initial period of use of the catalyst with duration of 3 - 45 days form a mixed stream of reagents by adding a compound of an alkali metal in the original thread containing alkylaromatics hydrocarbons in sufficient quantity to save basically constant degree of conversion and selectivity of the catalyst, and then the mixed stream is sent to the dehydrogenation reactor.

38. The method according to p. 37, characterized in that the catalyst consists essentially of 40 to 80% Fe2O3and 5 - 30% K2O.

39. The method according to p. 37, characterized in that the compound of the alkali metal added continuously in the original thread.

40. The method according to p. 37, characterized in that the compound of the alkali metal is added to the flow of raw materials periodically.

41. The method according to p. 37, characterized in that the number of connections of an alkali metal equivalent to a continuous addition of from 0.01 to 100 hours per million by weight of compounds of alkali metal relative to the total weight of the mixed flow of the reactants.

42. The method according to p. 37, characterized in that alkylaromatic hydrocarbon is an ethylbenzene, and alkenylamine hydrocarbon is a styrene.

43. The method according to p. 37, wherein the amount of compounds of alkaline which were established in the end of the initial period of the air-conditioning of the catalyst.

44. The method according to p. 37, characterized in that the compound of the alkali metal is a compound of potassium or sodium.

45. The method according to p. 44, characterized in that the compound of sodium or potassium are selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium oxide, potassium oxide, sodium carbonate, potassium carbonate and mixtures thereof.

46. The method according to p. 37, characterized in that the compound of the alkali metal is potassium hydroxide.

47. The method according to p. 27, characterized in that the compound of the alkali metal is added in a dry, solid form.

48. The method according to p. 37, characterized in that the compound of the alkali metal in the solid or liquid state is injected into the stream of the source reagent.

49. The method according to p. 37, characterized in that the compound of the alkali metal is added in aqueous solution.

50. The method according to p. 37, characterized in that the compound of the alkali metal is added in the form of steam.

51. The method according to p. 37, characterized in that the compound of the alkali metal is added in liquid form.

52. The method according to p. 37, characterized in that the catalytic dehydrogenation is carried out at practically constant temperature of reaction.

53. How is SS="ptx2">

54. Installing the dehydrogenation of alkylaromatic hydrocarbons in alkenylamine hydrocarbon containing at least one reaction chamber, loaded iron oxide catalyst, activated alkaline metal tool input stream in the reaction chamber by means of a pipeline for supplying the mixed flow of the reactants and the output medium flow from the reaction chamber, characterized in that it is provided with means for supplying compounds of the alkali metal in the mixed flow to maintain a mostly constant degree of conversion of alkylaromatic hydrocarbon and selectivity get alkanolamides hydrocarbon.

55. Installation according to p. 54, characterized in that it has placed on the output medium flow from the reaction chamber by means of control of the chemical composition of the exit stream.

56. Installation according to p. 55, characterized in that it is equipped with actuating mechanism connected to the control means and means for supplying compounds of an alkali metal.

57. Installation according to p. 54, characterized in that the means for supplying compounds of the alkali metal is arranged to actuate manually.

58. The mouth is doing automatically.

59. Installation according to p. 54, characterized in that the iron oxide catalyst, activated alkaline metal, contains mainly the following components:

Fe2O3- 40 - 80%

K2O - 5 - 30%

60. Installation according to p. 55, characterized in that it is made in the form of a series of consecutive reaction chambers, each associated with the corresponding vehicle control.

61. Installation under item 60, wherein each reaction chamber equipped with appropriate means for supplying compounds of an alkali metal and an actuator connected to each other, and respective control means for the actuating means of the filing of an alkali metal to obtain a signal for reducing the degree of conversion or selectivity to the preset value.

 

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