WO2014014466A1

WO2014014466A1 - Regeneration of a hydrogenation catalyst

Info

Publication number: WO2014014466A1
Application number: PCT/US2012/047399
Authority: WO
Inventors: David Lee VALDEZ
Original assignee: Invista Technologies S.A R.L.
Priority date: 2012-07-19
Filing date: 2012-07-19
Publication date: 2014-01-23
Also published as: EP2874743A1; CN104602812A; JP2015528741A; KR20150036632A

Abstract

The following example is a method treating a cyclohexylhydroperoxide (CHHP) hydrogenation catalyst. A reactor is provided that is filled with a partially deactivated hydrogenation catalyst from a CHHP hydrogenation process. A regeneration stream is then fed into the reactor, wherein the regeneration stream is a portion of the product mixture from the CHHP hydrogenation process. The partially deactivated hydrogenation catalyst is then contacted with the regeneration stream and finally the used regeneration stream is recovered from the reactor.

Description

REGENERATION OF A HYDROGENATION CATALYST

FIELD OF THE INVENTION

[0001] This disclosure relates to a process for regeneration of a hydrogenation catalyst. More specifically, it relates to a method to activate partially deactivated cyclohexylhydroperoxide hydrogenation catalyst by treatment with a regeneration stream.

BACKGROUND OF THE INVENTION

[0002] The air oxidation of cyclohexane is an important process for the production of caprolactam and adipic acid, which are used in the manufacture of synthetics such as nylon. The oxidation of cyclohexane by air produces a reaction product comprising cyclohexanol (A), cyclohexanone (K) cyclohexylhydroperoxide (CHHP) and small amounts of by-products. Cyclohexanone and cyclohexanol are the main product of the overall process and the mixture is commonly known as KA oil.

Several patents, herein incorporated by reference, such as U.S. Patent Nos.

3,530,185, 3,987,100, 5,780,683, 6,888,034 and 6,703,529 teach the preparation of a mixture containing cyclohexanol, cyclohexanone and cyclohexylhydroperoxide by the air oxidation of cyclohexane.

[0003] To achieve optimal yields of cyclohexanone and cyclohexanol, the oxidation of cyclohexane is usually carried out to maximize the yield of

cyclohexylhydroperoxide (CHHP). The cyclohexylhydroperoxide can then be converted to Cyclohexanone and cyclohexanol via hydrogenation. The preparation of cyclohexanol and cyclohexanone from cyclohexylhydroperoxide by hydrogenation using a group VIII catalyst deposited on an inert support is described in U.S. Patent No. 3,694,511 , herein incorporated by reference.

[0004] The hydrogenation process suffers from progressive fouling of the catalyst resulting in increased pressure drop, reduced conversion and yield, or both. To resolve this issue various methods may be employed to regenerate the

hydrogenation catalyst. Several patents, herein incorporated by reference, such as U.S. Patent Nos. 4,322,315, 6,905,997 and U.S. Patent Application No.

201 1/0008238 teach methods of regenerating the catalyst by washing with organic solvents. In addition, U.S .Patent Nos. 7,384,882 and 4,072,628 teach methods of regenerating hydrogenation catalysts by treatment with acid rich streams.

[0005] Methods for regenerating hydrogenation catalysts that require the addition of solvents to the hydrogenation process can be extremely costly and time consuming. This is because they require the equipment to be taken off line so that the catalyst can be washed with the solvents. The solvents will also have to eventually be removed from the process. These additional steps will require substantial capital costs and additional process equipment.

[0006] Therefore, there is a need for an improved process for the regeneration of a spent catalyst from a hydrogenation process, wherein the shut down time for the hydrogenation process, the need for additional process equipment, and the time and capital costs for the catalyst regeneration process are all minimized.

SUMMARY OF THE INVENTION

[0007] The present invention relates to an improved process for the

regeneration of a spent CHHP hydrogenation catalyst. By utilizing a portion of the product stream from the hydrogenation process to regenerate the spent catalyst, the shut down time for the hydrogenation process, the need for

additional process equipment, and the time and capital costs for the catalyst regeneration process are all minimized or eliminated.

[0008] An embodiment of the present invention comprises the steps of;

a) providing a reactor filled with a partially deactivated hydrogenation catalyst from a CHHP hydrogenation process;

b) feeding a regeneration stream into the reactor, wherein the

regeneration stream is a portion of the product mixture from the CHHP

hydrogenation process;

c) contacting the partially deactivated hydrogenation catalyst with the regeneration stream; and

d) recovering a used regeneration stream from the reactor.

[0009] In another embodiment, the hydrogenation process is the

hydrogenation of CHHP to cyclohexanone and cyclohexanol. [0010] In another embodiment, the regeneration stream comprises cyclohexanone and cyclohexanol.

[0011] In another embodiment, wherein the regeneration stream is heated to a temperature in the range of about 140°C to about 190°C prior to being fed to the hydrogenation reactor.

[0012] In another embodiment, wherein the reactor is maintained at a

pressure to prevent vapor flashing of the regeneration stream.

[0013] In another embodiment, wherein the regeneration stream is fed into the reactor until the partially deactivated hydrogenation catalyst has been

heated uniformly to the temperature of the regeneration stream.

[0014] In another embodiment, the feed of the regeneration stream is

discontinued when at least a portion of the catalytic activity of the partially

deactivated hydrogenation has been restored.

[0015] In another embodiment the stream recovered in step (d) comprises surface deposits that were removed from the catalyst

[0016] In another embodiment, the CHHP hydrogenation catalyst

comprises a Group VIII metal on an inert substrate.

[0017] In another embodiment, the Group VIII metal is selected from a

group comprising ruthenium, platinum and palladium.

[0018] In another embodiment, the inert substrate is selected from a group comprising carbon, alumina, silica and titanium dioxide.

[0019] In another embodiment, the CHHP hydrogenation catalyst contains the Group VIII metal in a range of about 0.1 to about 1.0% by weight.

[0020] In another embodiment, the CHHP hydrogenation catalyst is

palladium on an alumina substrate.

BRIEF DESCRIPTION OF THE DRAWING

[0021] The figure is a process diagram depicting an embodiment of the

present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention relates to an improved process for the regeneration of a spent cyclohexylhydroperoxide (CHHP) hydrogenation catalyst. [0023] All patents, patent applications, test procedures, priority documents, articles, publications, manuals, and other documents cited herein are fully incorporated by reference to the extent such disclosure is not inconsistent with this invention and for all jurisdictions in which such incorporation is permitted.

[0024] The embodiments of the current invention utilize a portion of the

product stream from a CHHP hydrogenation process to regenerate the spent

CHHP hydrogenation catalyst. The use of a portion of the product stream as a regeneration stream minimizes or eliminates the shut down time for the

hydrogenation process, the need for additional process equipment, and the

time and capital costs for the catalyst regeneration process.

[0025] The CHHP hydrogenation catalyst is regenerated by removing surface deposits from the catalyst by washing with a regeneration stream at elevated temperatures. This restores better flow distribution, reduces pressure drop and improves the overall bed activity enabling extended use of a single batch of catalyst. The process also extends the life of catalyst without having to remove it from the reaction vessel. Once removed, catalyst is typically reprocessed to recover precious metals which are then used with new supports to make new catalyst.

[0026] Referring to the Figure, an exemplary embodiment of the present invention is herein described. In typical use, the CHHP hydrogenation reactor 100 is filled with CHHP hydrogenation catalyst 110. The CHHP hydrogenation catalyst comprises a Group VIII metal on an inert substrate. The Group VIII metal can be selected from a group comprising ruthenium, platinum and palladium in a range of about 0.1 to about 1.0% by weight. The inert substrate can be selected from a group comprising carbon, alumina, silica and titanium dioxide. In an exemplary embodiment of the current invention, the CHHP hydrogenation catalyst is palladium on an alumina substrate. The CHHP is fed to reactor 100 through hydrogenator feed 120. Gas is fed to the reactor through in line 130 and recovered in line 150 and the cyclohexanone (K) and cyclohexanol (A) products are recovered through the hydrogenation product stream 130. During the catalyst regeneration process of the current invention, these process streams 120,130,150 are shut down.

[0027] Regeneration of the spent hydrogenation catalyst 110 is carried out by first filling the reactor 100 to above the catalyst bed with a regeneration stream 70. The regeneration stream may be a portion of the cyclohexanone (K) and cyclohexanol (A) product stream 160. The product stream 160 typically contains from about 2% to about 14% water and from about 1 % to about 3% other impurities by weight. The reactor 100 is placed under pressure to prevent vapor flashing of the regeneration stream 170 and is circulated from below the catalyst bed, through a heater 200 and fed back in above the catalyst bed. The heater 200 may be provided specifically for the regeneration process, or may be the feed preheater. In exemplary embodiments of the current invention the heating medium is steam. The regeneration stream 170 is heated to a range of from about 40°C to about 190°C and continues until the catalyst bed has been heated uniformly to the circulating temperature. Samples from the regeneration stream 170 are withdrawn and tested to assess the effectiveness of the catalyst regeneration. For example, this can be accomplished by analyzing for increases in impurities such as di-basic acids, or by observing color change.

[0028] Circulation of the regeneration stream 170 is continued until no more impurities are removed. A typical regeneration stream wash cycle lasts between 24 and 48 hours. The regenerated hydrogenation catalyst 1 10, with at least a portion of the catalytic activity restored, can then be used again in the hydrogenation process. Badly fouled catalyst beds may require more than one regeneration wash cycle to clean. Regeneration is typically required once per year. On completion of the regeneration process, the used regeneration stream 180 is fed back through the refining process, restoring the material to normal product. The surface deposits removed from the CHHP hydrogenation catalyst exits the process as part of the refining column tails stream.

Examples

[0029] The following Examples demonstrate the present invention and its capability for use. The invention is capable of other and different embodiments, and its several details are capable of modifications in various apparent respects, without departing from the scope and spirit of the present invention. Accordingly, the Examples are to be regarded as illustrative in nature and non-limiting.

Example 1

[0030] The effect of treating the deactivated catalyst with a regeneration stream using the process described above was tested at I VISTA's Victoria Plant. The benefit of treatment with a regeneration stream was tested by measuring the resistance of flow through the catalyst bed. When the catalyst was deactivated, the resistance was at a high level due to fouling of the catalyst bed. The resistance to flow through the catalyst bed is measured by the formula: R = ΔΡ/F², wherein R is the resistance, Δ P is the pressure drop through the catalyst and F is the flow rate through the catalyst bed. A regeneration stream comprising cyclohexanone (K) and cyclohexanol (A) from the hydrogenation product stream was heated to target temperature of 180 °C and passed through the catalyst bed at a velocity of in the range of between 1 E-3ms^"1 to 3E-3ms^"1 for a duration of between 24 and 48 hours. It was found that the resistance, R, was reduced by between 5% to 15% each time the catalyst bed was treated with the regenerations stream. This indicates that a portion of the catalytic activity was restored and the catalyst was in condition to be used in the hydrogenation process.

Example 2

[0031] 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. The regeneration stream was run through the catalyst bed when the conversion of CHHP reached a predetermined baseline. When the baseline conversion as reached, the CHHP hydrogenation catalyst was considered deactivated. After each treatment with the regeneration stream, the conversion of CHHP was tested to have increased by 3%- 4%. As in Example 1 , this indicates that a portion of the catalytic activity was restored and the deactivated catalyst was in condition to be used in the hydrogenation process.

Example 3

[0032] The following example is a method treating a cyclohexylhydroperoxide (CHHP) hydrogenation catalyst. A reactor is provided that is filled with a partially deactivated hydrogenation catalyst from a CHHP hydrogenation process. A

regeneration stream is then fed into the reactor, wherein the regeneration stream is a portion of the product mixture from the CHHP hydrogenation process. The partially deactivated hydrogenation catalyst is then contacted with the regeneration stream and finally the used regeneration stream is recovered from the reactor.

Example 4

[0033] The process of Example 3 is repeated with additional steps. In this example, the hydrogenation process is the hydrogenation of CHHP to cyclohexanone and cyclohexanol. Example 5

[0034] The process of Example 4 is repeated with additional steps. In this example, the regeneration stream comprises cyclohexanone and cyclohexanol.

Example 6

[0035] 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 40°C to about 190°C prior to being fed to the hydrogenation reactor.

Example 7

[0036] The process of Example 6 is repeated with additional steps. In this example, the reactor is maintained at a pressure to prevent vapor flashing of the regeneration stream.

Example 8

[0037] The process of Example 7 is repeated with additional steps. In this example, the regeneration stream is fed into the reactor until the partially deactivated

hydrogenation catalyst has been heated uniformly to the temperature of the

regeneration stream.

Example 9

[0038] The process of Example 8 is repeated with additional steps. In this example, wherein the feed of the regeneration stream is discontinued when at least a portion of the catalytic activity of the partially deactivated hydrogenation has been restored.

Example 10

[0039] The process of Example 9 is repeated with additional steps. In this example, the used regeneration stream recovered in step (d) comprises surface deposits that were removed from the catalyst. Example 11

[0040] 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

[0041] The process of Example 11 is repeated with additional steps. In this example, the Group VIII metal is selected from a group comprising ruthenium, platinum and palladium.

Example 13

[0042] The process of Example 12 is repeated with additional steps. In this example, the inert substrate is selected from a group comprising carbon, alumina, silica and titanium dioxide.

Example 14

[0043] The process of Example 13 is repeated with additional steps. In this example, the CHHP hydrogenation catalyst contains the Group VIII metal in a range of about 0.1 to about 1.0% by weight.

Example 15

[0044] The process of Example 14 is repeated with additional steps. In this example, the CHHP hydrogenation catalyst is palladium on an alumina substrate.

[0045] It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed herein in a range format. It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a concentration range of "about 0.1% to about 5%" should be interpreted to include not only the explicitly recited concentration of about 0.1 wt% to about 5 wt%, but also the individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range. The term "about" can include ±1 %, ±2%, ±3%, ±4%, ±5%, ±8%, or ±10%, of the numerical value(s) being modified. In addition, the phrase "about 'x' to 'y'" includes "about 'x' to about y".

[0046] While the illustrative embodiments of the invention have been described with particularity, it will be understood that the invention is capable of other and different embodiments and that various other modifications will be apparent to and may be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims hereof be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present disclosure, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains.

Claims

CLAIMS What is claimed:

1. A method for treating a cyclohexylhydroperoxide (CHHP) hydrogenation catalyst comprising the steps of:

b) feeding a regeneration stream into the reactor, wherein the regeneration stream is a portion of the product mixture from the CHHP hydrogenation process;

c) contacting the partially deactivated hydrogenation catalyst with the

regeneration stream; and

d) recovering a used regeneration stream from the reactor.

2. The method of claim 1 wherein the hydrogenation process is the hydrogenation of CHHP to cyclohexanone and cyclohexanol.

3. The method of claim 1 wherein the regeneration stream comprises

cyclohexanone and cyclohexanol.

4. The method of claim 1 wherein the regeneration stream is heated to a

temperature in the range of about 140°C to about 190°C prior to being fed to the hydrogenation reactor.

5. The method of claim 1 wherein the reactor is maintained at a pressure to prevent vapor flashing of the regeneration stream.

6. The method of claim 1 wherein the regeneration stream is fed into the reactor until the partially deactivated hydrogenation catalyst has been heated uniformly to the temperature of the regeneration stream.

7. The method of claim 1 wherein the feed of the regeneration stream is

discontinued when at least a portion of the catalytic activity of the partially deactivated hydrogenation has been restored.

8. The method of claim 1 wherein the used regeneration stream recovered in step (d) comprises surface deposits that were removed from the catalyst.

9. The method of claim 1 wherein the CHHP hydrogenation catalyst comprises a Group VIII metal on an inert substrate.

10. The method of claim 8 wherein the Group VIII metal is selected from a group comprising ruthenium, platinum and palladium.

11.The method of claim 8 wherein the inert substrate is selected from a group comprising carbon, alumina, silica and titanium dioxide.

12. The method of claim 8 wherein the CHHP hydrogenation catalyst contains the Group VIII metal in a range of about 0.1 to about 1.0% by weight.

13. The method of claim 1 1 wherein the CHHP hydrogenation catalyst is palladium on an alumina substrate.