JP2015528741A - Regeneration of hydrogenation catalyst - Google Patents

Abstract

The following example is a method for treating a cyclohexyl hydroperoxide (CHHP) hydrogenation catalyst. A reactor charged with a partially deactivated hydrogenation catalyst from the CHHP hydrogenation process is provided. A regeneration stream is then fed to the reactor, where the regeneration stream is part of the product mixture from the CHHP hydrogenation process. The partially deactivated hydrogenation catalyst is then contacted with the regeneration stream and finally the spent regeneration stream is recovered from the reactor. [Selection] Figure 1

Description

  The present disclosure relates to a hydrogenation catalyst regeneration process. More specifically, it relates to a process for activating a partially deactivated cyclohexyl hydroperoxide hydrogenation catalyst by treatment with a regeneration stream.

  Air oxidation of cyclohexane is an important process for the production of caprolactam and adipic acid used in the production of synthetic products such as nylon. Oxidation of cyclohexane with air produces a reaction product containing cyclohexanol (A), cyclohexanone (K), cyclohexyl hydroperoxide (CHHP) and a small amount of by-products. Cyclohexanone and cyclohexanol are the main products of all processes and the mixture is commonly known as KA oil. Several patents (incorporated herein by reference), such as US Pat. Nos. 3,530,185, 3,987,100, 5,780,683, 6,888,034 No. and 6,703,529 teach the preparation of mixtures containing cyclohexanol, cyclohexanone and cyclohexyl hydroperoxide by air oxidation of cyclohexane.

  In order to achieve optimal yields of cyclohexanone and cyclohexanol, the oxidation of cyclohexanone is usually carried out to maximize the yield of cyclohexyl hydroperoxide (CHHP). The cyclohexyl hydroperoxide can then be converted to cyclohexanone and cyclohexanol by hydrogenation. The preparation of cyclohexanol and cyclohexanone from cyclohexyl hydroperoxide by hydrogenation using a Group VIII catalyst deposited on an inert support is described in US Pat. No. 3,694,511, the description of which is hereby incorporated by reference. Incorporated by reference).

  The hydrogenation process experiences progressive fouling of the catalyst, resulting in increased pressure drop, conversion and reduced yield or both. To solve this problem, the hydrogenation catalyst can be regenerated using various methods. Some patents (incorporated herein by reference), such as US Pat. Nos. 4,322,315, 6,905,997 and US Patent Application 2011/0008238, are washed with an organic solvent. Teaches how to regenerate the catalyst. In addition, US Pat. Nos. 7,384,882 and 4,072,628 teach a method for regenerating a hydrogenation catalyst by treatment with an acid-concentrated stream.

  A method for regenerating a hydrogenation catalyst that requires the addition of a solvent to the hydrogenation process can be very expensive and time consuming. This is because they require equipment to be removed from the line so that the catalysts can be washed with solvent. The solvent will eventually have to be removed from the process as well. These additional steps will require substantial capital costs and additional process equipment.

  Therefore, an improved process for regeneration of spent catalyst from the hydrogenation process is required, in which case the shutdown time for the hydrogenation process, the need for additional process equipment, and the catalyst regeneration process All the time and capital costs to minimize are minimized.

  The present invention relates to an improved process for the regeneration of spent CHHP hydrogenation catalysts. By utilizing a portion of the product stream from the hydrogenation process to regenerate spent catalyst, the shutdown time for the hydrogenation process, the need for additional process equipment, and the time and capital for the catalyst regeneration process All costs are minimized or eliminated.

One embodiment of the present invention includes the following:
a) providing a reactor packed with a partially deactivated hydrogenation catalyst from the CHHP hydrogenation process;
b) supplying a regeneration stream into the reactor, the regeneration stream being part of the product mixture from the CHHP hydrogenation process;
c) contacting the partially deactivated hydrogenation catalyst with the regeneration stream; and d) recovering the spent regeneration stream from the reactor.

  In another embodiment, the hydrogenation step is hydrogenation of CHHP to cyclohexanone and cyclohexanol.

  In another embodiment, the regeneration stream comprises cyclohexanone and cyclohexanol.

  In another embodiment, the regeneration stream is heated to a temperature in the range of about 140 ° C. to about 190 ° C. before being fed to the hydrogenation reactor.

  In another embodiment, the reactor is maintained at a pressure that prevents steam flush of the regenerative stream.

  In another embodiment, the regeneration stream is fed to the reactor until the partially deactivated hydrogenation catalyst is uniformly heated to the temperature of the regeneration stream.

  In another embodiment, the regeneration stream feed is interrupted when at least a portion of the catalytic activity of the partially deactivated hydrogenation is restored.

  In another embodiment, the stream recovered in step (d) includes surface deposits removed from the catalyst.

  In another embodiment, the CHHP hydrogenation catalyst comprises a Group VIII metal on an inert substrate.

  In another embodiment, the Group VIII metal is selected from the group consisting of ruthenium, platinum and palladium.

  In another embodiment, the inert substrate is selected from the group consisting of carbon, alumina, silica and titanium dioxide.

  In another embodiment, the CHHP hydrogenation catalyst contains a Group VIII metal in the range of about 0.1 to about 1.0 weight percent.

  In another embodiment, the CHHP hydrogenation catalyst is palladium on an alumina substrate.

It is process drawing which shows embodiment of this invention.

  The present invention relates to an improved process for the regeneration of spent cyclohexyl hydroperoxide (CHHP) hydrogenation catalysts.

  All patents, patent applications, test procedures, priority documents, papers, publications, manuals and other documents cited herein are to the extent that such disclosure is consistent with the present invention, and such With respect to the authority allowed to be incorporated, these descriptions are incorporated herein by reference.

  Embodiments of the present invention utilize a portion of the product stream from the CHHP hydrogenation process to regenerate spent CHHP hydrogenation catalyst. The use of a portion of the product stream as the regeneration stream minimizes or eliminates shutdown time for the hydrogenation process, the need for additional process equipment, and time and capital costs for the catalyst regeneration process.

  The CHHP hydrogenation catalyst is regenerated by removing surface deposits from the catalyst by washing with a regeneration stream at an elevated temperature. This restores better flow distribution, reduces pressure drop, and improves overall bed activity, allowing widespread use of a single batch of catalyst. The process also extends the life of the catalyst without having to be removed from the reaction vessel. Once removed, the catalyst is typically reprocessed to recover the precious metal, which is then used with a new support to produce a new catalyst.

  Exemplary embodiments of the present invention will now be described with reference to the drawings. In typical use, the CHHP hydrogenation reactor 100 is filled with a CHHP hydrogenation catalyst 110. The CHHP hydrogenation catalyst comprises a Group VIII metal on an inert substrate. The Group VIII metal may be selected from the group consisting of ruthenium, platinum and palladium in the range of about 0.1 to about 1.0% by weight. The inert substrate can be selected from the group consisting of carbon, alumina, silica and titanium dioxide. In an exemplary embodiment of the invention, the CHHP hydrogenation catalyst is palladium on an alumina substrate. The CHHP is supplied to the reactor 100 through the hydrogen additive supply device 120. Gas is fed to the reactor via line 130 and recovered in line 150, and cyclohexanone (K) and cyclohexanol (A) products are recovered via hydrogenation product stream 130. During the catalyst regeneration process of the present invention, these process streams 120, 130, 150 are shut down.

  The regeneration of the spent hydrogenation catalyst 110 is performed by first filling the reactor 100 with the regeneration stream 170 over the catalyst bed. The regenerative stream can be part of a cyclohexanone (K) and cyclohexanol (A) product stream 160. Product stream 160 typically contains about 2% to about 14% by weight water and about 1% to about 3% by weight of other impurities. Reactor 100 is placed under pressure to prevent steam flushing of regeneration stream 170 and is circulated from below the catalyst bed through heater 200 and fed back onto the catalyst bed. The heat generator 200 may specifically be provided for a regeneration process or may be a feed preheater. In an exemplary embodiment of the invention, the heating medium is water vapor. The regeneration stream 170 is heated to a range of about 140 ° C. to about 190 ° C. and continues until the catalyst bed is uniformly heated to the circulation temperature. A sample from the regeneration stream 170 is drawn and tested to evaluate the effectiveness of catalyst regeneration. For example, this can be accomplished by analyzing for an increase in impurities, such as dibasic acids, or by observing discoloration.

  Circulation of the regenerative stream 170 is continued until no more impurities are removed. A typical regenerative flow wash cycle lasts 24 to 48 hours. The regenerated hydrogenation catalyst 110 (having at least a portion of the recovered catalytic activity) can then be used again in the hydrogenation step. A fouled catalyst bed may require more than one regenerative wash cycle to be normal. Regeneration is typically required once a year. At the completion of the regeneration process, the spent regeneration stream 180 is fed back through the purification process to restore the material to normal product. Surface deposits removed from the CHHP hydrogenation catalyst exit the process as part of the purification column tail stream.

Examples The following examples demonstrate the invention and its ability to be used. The invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, without departing from the scope and spirit of the invention. Accordingly, this example is to be considered as illustrative and non-limiting in nature.

Example 1
The effect of treating the deactivated catalyst with a regenerative stream using the above process was tested in an INVISTA's Victoria plant. The benefits of treatment with the regenerative stream were tested by measuring the resistance of flow through the catalyst bed. When the catalyst was deactivated, the resistance was at the highest level due to contamination of the catalyst bed. The resistance to flow through the catalyst bed is given by the equation: R = ΔP / F ² , where R is the resistance, ΔP is the pressure drop across the catalyst, and F is the flow rate through the catalyst bed. taking measurement. A regeneration stream comprising cyclohexanone (K) and cyclohexanol (A) from the hydrogenation product stream is heated to a target temperature of 180 ° C. at a rate in the range of 1E-3 ms ^{−1 to} 3E-3 ms ⁻¹ at 24 to Passed through the catalyst bed for 48 hours. It has been found that each time the catalyst bed is treated with a regenerative stream, the resistance R is reduced by 5% to 15%. This indicates that a portion of the catalyst activity has been restored and the catalyst has been ready to be used in the hydrogenation process.

Example 2
The process of Example 1 is repeated with additional steps. In this example, the conversion of CHHP in the hydrogenation process was tested before and after treatment of the CHHP hydrogenation catalyst with a regeneration stream. When CHHP conversion reached the planned baseline, a regeneration stream was passed through the catalyst bed. Once baseline conversion was reached, the CHHP hydrogenation catalyst was considered deactivated. After each treatment with the regeneration stream, it was tested that the conversion of CHHP was increased by 3% to 4%. As in Example 1, this indicates that a portion of the catalyst activity has been restored and that the deactivated catalyst has met the conditions to be used in the hydrogenation process.

Example 3
The following example is a method for treating a cyclohexyl hydroperoxide (CHHP) hydrogenation catalyst. A reactor charged with a partially deactivated hydrogenation catalyst from the CHHP hydrogenation process is provided. A regeneration stream is then fed to the reactor, where the regeneration stream is part of the product mixture from the CHHP hydrogenation process. The partially deactivated hydrogenation catalyst is then contacted with the regeneration stream and finally the spent regeneration stream is recovered from the reactor.

Example 4
The process of Example 3 is repeated with additional steps. In this example, the hydrogenation step is the hydrogenation of CHHP to cyclohexanone and cyclohexanol.

Example 5
The process of Example 4 is repeated with additional steps. In this example, the regeneration stream comprises cyclohexanone and cyclohexanol.

Example 6
The process of Example 5 is repeated with additional steps. In this example, the regeneration stream is heated to a temperature in the range of about 140 ° C. to about 190 ° C. before being fed to the hydrogenation reactor.

Example 7
The process of Example 6 is repeated with additional steps. In this example, the reactor is held at a pressure to prevent steam flushing of the regeneration stream.

Example 8
The process of Example 7 is repeated with additional steps. In this example, the regeneration stream is fed to the reactor until the partially deactivated hydrogenation catalyst is uniformly heated to the temperature of the regeneration stream.

Example 9
The process of Example 8 is repeated with additional steps. In this embodiment, the regeneration stream feed is interrupted when at least part of the catalytic activity of the partially deactivated hydrogenation is restored.

Example 10
The process of Example 9 is repeated with additional steps. In this example, the spent regeneration stream recovered in step (d) contains surface deposits removed from the catalyst.

Example 11
The process of Example 10 is repeated with additional steps. In this example, the CHHP hydrogenation catalyst comprises a Group VIII metal on an inert substrate.

Example 12
The process of Example 11 is repeated with additional steps. In this example, the Group VIII metal is selected from the group consisting of ruthenium, platinum and palladium.

Example 13
The process of Example 12 is repeated with additional steps. In this example, the inert substrate is selected from the group consisting of carbon, alumina, silica and titanium dioxide.

Example 14
The process of Example 13 is repeated with additional steps. In this example, the CHHP hydrogenation catalyst contains a Group VIII metal in the range of about 0.1 to about 1.0 weight percent.

Example 15
The process of Example 14 is repeated with additional steps. In this example, the CHHP hydrogenation catalyst is palladium on an alumina substrate.

  It should be noted that ratios, concentrations, amounts and other numerical data can be represented herein in a range format. Such range formats are used for convenience and simplicity, and thus not only include numbers explicitly listed as range limits, but as if each number and subrange are explicitly listed. Should be construed flexibly as including all individual numerical values or subranges subsumed within that range. To illustrate, a concentration range of “about 0.1% to about 5%” is not only the explicitly listed concentration of about 0.1% to about 5% by weight, but also individual concentrations within the indicated range. (Eg 1%, 2%, 3% and 4%) and subranges (eg 0.5%, 1.1%, 2.2%, 3.3% and 4.4%) It should be. The term “about” includes the addition or subtraction of ± 1%, ± 2%, ± 3%, ± 4%, ± 5%, ± 8%, or ± 10% of the numerical value or values. Further, the phrase “about“ x ”to“ y ”” encompasses “about“ x ”to about“ y ””.

  While exemplary embodiments of the present invention have been described with specificity, the invention is capable of other and different embodiments, and various other modifications will be apparent to those skilled in the art, and It should be understood that it can be easily done by those skilled in the art without departing from the spirit and scope. Accordingly, the claims herein are not intended to be limited to the examples and descriptions described herein, but rather, the claims are subject to patents present in the disclosure of the present invention. All features with possible novelty are intended to include all features that are treated as equivalents, for example, by one of ordinary skill in the art to which this invention pertains.

Claims (13)

A method for treating a cyclohexyl hydroperoxide (CHHP) hydrogenation catalyst comprising:
a) providing a reactor packed with a partially deactivated hydrogenation catalyst from the CHHP hydrogenation process;
b) supplying a regeneration stream into the reactor, wherein the regeneration stream is part of the product mixture from the CHHP hydrogenation process;
c) contacting the partially deactivated hydrogenation catalyst with the regeneration stream; and d) recovering the spent regeneration stream from the reactor.   The process of claim 1, wherein the hydrogenation step is hydrogenation of CHHP to cyclohexanone and cyclohexanol.   The method of claim 1, wherein the regeneration stream comprises cyclohexanone and cyclohexanol.   The process of claim 1, wherein the regeneration stream is heated to a temperature in the range of about 140 ° C. to about 190 ° C. before being fed to the hydrogenation reactor.   The method of claim 1, wherein the reactor is maintained at a pressure that prevents vapor flash of the regeneration stream.   The process of claim 1, wherein the regeneration stream is fed to the reactor until the partially deactivated hydrogenation catalyst is uniformly heated to the temperature of the regeneration stream.   The process of claim 1, wherein the regeneration stream feed is interrupted when at least a portion of the catalytic activity of the partially deactivated hydrogenation is restored.   The method of claim 1, wherein the spent regeneration stream recovered in step (d) comprises surface deposits removed from the catalyst.   The process of claim 1, wherein the CHHP hydrogenation catalyst comprises a Group VIII metal on an inert substrate.   The method of claim 8, wherein the Group VIII metal is selected from the group consisting of ruthenium, platinum and palladium.   9. The method of claim 8, wherein the inert substrate is selected from the group consisting of carbon, alumina, silica, and titanium dioxide.   9. The method of claim 8, wherein the CHHP hydrogenation catalyst contains the Group VIII metal in the range of about 0.1 to about 1.0 weight percent.   The method of claim 11, wherein the CHHP hydrogenation catalyst is palladium on an alumina substrate.