Process and system for recovery of cumene and co-production of acetophenone and applications

Abstract

This invention discloses a method, system, and application for the recovery of cumene and the co-production of acetophenone. The method of this invention includes the following steps: (1) distilling a material to be treated containing cumene, phenol, and acetophenone, collecting cumene product from the top of the distillation column and collecting a heavy component I containing acetophenone from the bottom; (2) further distilling the heavy component I containing acetophenone, collecting a circulating stream from the top of the distillation column and optionally recycling it back to step (1) for distillation together with the material to be treated, collecting heavy component II from the bottom of the distillation column, and collecting acetophenone product from the side stream of the distillation column. The method for the recovery of cumene and the co-production of acetophenone provided by this invention can efficiently recover cumene while also efficiently recovering acetophenone, has the advantage of a simple process, and recovers a high-purity acetophenone product with low phenol content, which can significantly improve the technical and economic efficiency of the equipment.

Description

Technical Field

[0001] This invention relates to the technical field of cumene and acetophenone recovery, and more specifically, to methods, systems, and applications for cumene recovery and co-production of acetophenone. Background Technology

[0002] The cumene hydroperoxide (CHP) process for producing propylene oxide includes a benzyl alcohol hydrogenolysis unit, and the efficient recovery and recycling of the reaction product cumene is one of the key aspects of the process. In addition to cumene, the hydrogenolysis reaction products also include byproducts such as acetophenone and phenol.

[0003] Efficient recycling of cumene is crucial and significantly affects the techno-economic performance of the plant. In addition, acetophenone, a product of hydrogenolysis, is a high-value-added product, and efficient recovery of acetophenone can significantly improve the techno-economic performance of the plant.

[0004] In the prior art, Chinese patent CN115991640A discloses a method for recovering acetophenone, which uses an alkaline water method to recover and separate phenol from acetophenone. However, this method has the problem that the density of acetophenone is close to that of the aqueous phase, making phase separation difficult.

[0005] Therefore, there is a need to develop a better method for the recovery of cumene and the co-production of acetophenone. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention proposes a method, system, and application for the recovery of cumene and the co-production of acetophenone. The method for the recovery of cumene and the co-production of acetophenone provided by this invention efficiently recovers both cumene and acetophenone, has the advantages of a simple process, and yields a high-purity acetophenone product with low phenol content, significantly improving the technical and economic efficiency of the equipment.

[0007] One objective of this invention is to provide a method for the recovery of cumene and the co-production of acetophenone, comprising the following steps:

[0008] (1) The material to be treated containing cumene, phenol and acetophenone is distilled, and the cumene product is collected from the top of the column and the heavy component containing acetophenone is collected from the bottom of the column.

[0009] (2) Further distill the heavy component I containing acetophenone, collect the circulating stream from the top of the column and optionally return it to step (1) for distillation together with the material to be processed, collect the heavy component II from the bottom of the column, and collect the acetophenone product from the side stream of the column.

[0010] The inventors of this invention discovered that phenol, under certain pressure, forms an azeotrope with acetophenone, which is difficult to separate by conventional distillation; simultaneously, phenol also forms a low-boiling-point azeotrope with cumene. This invention utilizes the azeotropic properties of cumene and phenol to first separate acetophenone and phenol at the top of a distillation column; the bottom material containing a higher acetophenone content enters another distillation column (acetophenone recovery column) for further distillation. Furthermore, research has revealed an acetophenone enrichment zone within the acetophenone recovery column, from which acetophenone is produced via a side stream. Simultaneously, the removal of both light and heavy components within the acetophenone recovery column can be achieved, ultimately yielding an acetophenone product with a lower phenol content.

[0011] In the method for cumene recovery and co-production of acetophenone described in this invention, preferably,

[0012] The materials to be processed include cumene, phenol, acetophenone, and heavy components;

[0013] Preferably, by mass fraction, and more preferably, the material to be treated comprises 95%-99.5% cumene, 0.01%-1.0% phenol, 0.1%-3% acetophenone, and 0.01%-3% heavy components;

[0014] More preferably, the material to be treated comprises 96-98.5% cumene, 0.05-1.0% phenol, 1-2% acetophenone, and 0.5-1% heavy components;

[0015] For example, the materials to be processed include 96%, 97%, 98%, and 98.5% cumene;

[0016] The material to be processed includes 0.05%, 0.1%, 0.4%, 0.6%, 0.8%, and 1.0% phenol;

[0017] The material to be processed includes 1%, 1.2%, 1.4%, 1.6%, 1.8%, and 2.0% acetophenone;

[0018] The material to be processed includes 0.05%, 0.1%, 0.4%, 0.6%, 0.8%, and 1.0% heavy components;

[0019] More preferably, the material to be processed comes from the cumene recovery unit of the propylene oxide production process using the cumene peroxide method.

[0020] In the method for cumene recovery and co-production of acetophenone described in this invention, preferably,

[0021] Step (1),

[0022] The operating pressure at the top of the distillation column is 50-310 kPaA; preferably 51-300 kPaA; more preferably 51-200 kPaA; even more preferably 59-200 kPaA; further preferably 100-200 kPaA; and even more preferably 160-200 kPaA; for example, 50, 51, 55, 59, 65, 80, 100, 130, 160, 190, 200, 220, 240, 260, 280, 310 kPaA; and / or,

[0023] The operating temperature at the top of the distillation column is 125-200℃; preferably 150-180℃; for example, 125, 140, 150, 160, 180, 190, 200℃.

[0024] In the method for cumene recovery and co-production of acetophenone described in this invention, preferably,

[0025] Step (1),

[0026] The reboiler operating temperature of the distillation column is 140-240℃; preferably 150-200℃; for example, 140, 150, 160, 180, 190, 200, 220, 240℃; and / or,

[0027] The theoretical plate number of the distillation is 20-80; preferably 30-50; for example, 20, 30, 40, 50, 60, 70, 80.

[0028] In the method for cumene recovery and co-production of acetophenone described in this invention, preferably,

[0029] Step (2),

[0030] The operating pressure at the top of the distillation column is 1-30 kPaA; preferably 3-20 kPaA; more preferably 5-20 kPaA; for example, 1, 3, 5, 8, 10, 15, 20, 25, or 30 kPaA; and / or,

[0031] The operating temperature at the top of the distillation column is 40-110°C; preferably 50-100°C; more preferably 60-100°C; for example, 40, 50, 60, 80, 100, 105, or 110°C; and / or,

[0032] The reboiler operating temperature for further distillation is 140-240℃; preferably 160-215℃; more preferably 160-200℃; for example, 140, 150, 160, 180, 190, 200, 215, 220, 240℃.

[0033] In the method for cumene recovery and co-production of acetophenone described in this invention, preferably,

[0034] Step (2),

[0035] The theoretical plate number for further distillation is 15-50; preferably 15-40; for example, 15, 20, 30, 40, 50; and / or,

[0036] Acetophenone is collected from the side stream of the stripping section of the column; preferably, it is collected at a theoretical plate number of 10-40 (from top to bottom); more preferably, it is collected at a theoretical plate number of 15-40; and / or,

[0037] For example, acetophenone products can be sampled at theoretical plate numbers of 10, 15, 20, 25, 30, 35, and 40 (from top to bottom);

[0038] The extracted acetophenone product is a gas phase product, and preferably the extracted acetophenone product stream contains ≤5wt% phenol, more preferably ≤1wt% phenol.

[0039] The second objective of this invention is to provide a system for the recovery of cumene and the co-production of acetophenone, comprising, in the order of feeding, a cumene recovery tower and an acetophenone recovery tower:

[0040] The bottom outlet of the cumene recovery tower is connected to the inlet of the acetophenone recovery tower; the top outlet of the acetophenone recovery tower is optionally connected to the circulating material inlet of the cumene recovery tower; the stripping section of the acetophenone recovery tower is also equipped with a side stream material outlet.

[0041] The system described above is preferably used in the method for cumene recovery and co-production of acetophenone, which is one of the objectives of this invention.

[0042] In the cumene recovery and co-production of acetophenone system described in this invention, preferably,

[0043] The cumene recovery tower and the acetophenone recovery tower are each independently distillation towers; and / or,

[0044] The cumene recovery tower has a side feed inlet; and / or,

[0045] The top of the cumene recovery tower is provided with an isocumene product outlet; and / or,

[0046] The acetophenone recovery tower is also equipped with a bottom outlet.

[0047] In the cumene recovery and co-production of acetophenone system described in this invention, preferably,

[0048] The reflux ratio of the cumene recovery tower is 0.05-2, preferably 0.1-1; more preferably 0.1-0.5; for example, 0.05, 0.1, 0.5, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2; and / or,

[0049] The reflux ratio of the acetophenone recovery tower is 0.1-2, preferably 0.5-2; for example, 0.1, 0.5, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2.

[0050] In the cumene recovery and co-production of acetophenone system described in this invention, preferably,

[0051] The cumene recovery tower has a feed inlet at 10-40 theoretical trays (from top to bottom); preferably, it has a feed inlet at 15-30 theoretical trays (from top to bottom).

[0052] The acetophenone recovery tower has a feed inlet at 5-30 theoretical trays (from top to bottom), preferably at 5-20 theoretical trays (from top to bottom).

[0053] A third objective of this invention is to provide an application of the method described in one objective of this invention or the system described in another objective of this invention in the recovery of cumene and the co-production of acetophenone.

[0054] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] (1) This invention achieves efficient separation of acetophenone and phenol by controlling the appropriate distillation column pressure, and produces acetophenone while recovering cumene. It features a simple process, high purity of recovered acetophenone, and low phenol content.

[0057] (2) The present invention directly recovers high-purity acetophenone product from the side stream of the distillation column in the cumene de-gravity process, with low phenol content, which can significantly improve the technical and economic efficiency of the equipment. Attached Figure Description

[0058] Figure 1This is a schematic diagram of one embodiment of the system described in this invention;

[0059] Explanation of reference numerals in the attached figures:

[0060] 1 is the cumene recovery tower, 2 is the acetophenone recovery tower, 3 is the material to be processed, 4 is the cumene product, 5 is the heavy component I containing acetophenone, 6 is the acetophenone product, 7 is the heavy component II, and 8 is the top stream of the acetophenone recovery tower. Detailed Implementation

[0061] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0062] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0063] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0064] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0065] Test method:

[0066] 1. Component measurement:

[0067] The components of the material to be processed, cumene product, acetophenone product, etc., in this invention are measured using gas chromatography.

[0068] 2. The recovery rate Y1 of cumene is calculated according to the following formula:

[0069] Y1 = F1 (cumene) / F2 (cumene) × 100%;

[0070] In the formula, F1 (isopropylbenzene) is the mass flow rate of isopropylbenzene in the isopropylbenzene product stream; F2 (isopropylbenzene) is the mass flow rate of isopropylbenzene in the material to be processed.

[0071] 3. The recovery rate Y2 of acetophenone is calculated using the following formula:

[0072] Y2 = F1 (acetophenone) / F3 (acetophenone) × 100%;

[0073] In the formula, F1 (acetophenone) is the mass flow rate of acetophenone in the acetophenone product stream; F3 (acetophenone) is the mass flow rate of acetophenone in the material to be processed.

[0074]

Example 1

[0075] A system for the recovery of cumene and co-production of acetophenone, such as Figure 1 As shown, the feed sequence includes cumene recovery tower 1 and acetophenone recovery tower 2: the material to be processed 3 containing cumene, phenol, and acetophenone is fed into the cumene recovery tower for distillation; cumene product 4 (cumene product is an azeotrope of cumene and phenol) is collected from the top of the tower, and heavy component I5 containing acetophenone (in addition to acetophenone, it mainly contains cumene and isopropylbenzene) is collected from the bottom of the tower; the bottom outlet of the cumene recovery tower is connected to the inlet of the acetophenone recovery tower, and the heavy component I5 containing acetophenone is fed into the acetophenone recovery tower 2 for distillation;

[0076] After distillation in the acetophenone recovery tower, the top outlet of the acetophenone recovery tower is connected to the circulating material inlet of the cumene recovery tower. The top stream 8 of the acetophenone recovery tower is recycled back to the cumene recovery tower and distilled together with the material to be treated 3. Heavy component II 7 (mainly composed of cumene) is collected from the bottom of the cumene recovery tower. The stripping section of the acetophenone recovery tower is also equipped with a side stream material outlet. Acetophenone product 6 (mainly composed of an acetophenone-phenol azeotrope, with a very low phenol content) is collected from the side stream of the stripping section of the acetophenone recovery tower.

[0077]

Example 2

[0078] use Figure 1 The system shown is used for the recovery of cumene and the co-production of acetophenone. The specific method includes the following steps:

[0079] (1) The material to be treated, containing cumene, phenol, and acetophenone, is distilled in a cumene recovery tower. The cumene product is collected from the top of the tower, and the heavy component I containing acetophenone is collected from the bottom of the tower. The composition of the material to be treated is (by mass percentage): cumene 98.0%, acetophenone 1%, heavy component 0.8%, phenol 0.05%, and the remainder is other trace impurities.

[0080] The cumene recovery tower has a theoretical number of 40 plates, with the feed inlet located at 28 plates (from top to bottom). The top pressure is 150 kPaA, the reflux ratio is 0.3, and the temperature of the gas phase component extracted from the top of the tower (i.e., the top temperature) is 168℃. The bottom operating temperature is 185℃.

[0081] (2) The heavy component I containing acetophenone is further distilled in the acetophenone recovery tower. The circulating stream is collected from the top of the tower and recycled back to step (1) for distillation together with the material to be processed. The heavy component II is collected from the bottom of the tower, and the acetophenone product is collected from the side stream of the tower stripping section.

[0082] The acetophenone recovery tower has a theoretical number of 20 plates, 10 feed positions (from top to bottom), a tower top pressure of 5 kPaA, a reflux ratio of 0.5, a tower top temperature of 65°C for the gas phase components collected at the top of the tower, 15 side stream collection positions (from top to bottom), and a tower bottom operating temperature of 167°C.

[0083] The purity of the acetophenone product obtained by the above method (based on the total weight of acetophenone, phenol, cumene, and heavy components as 100%) was 98.26%, with a phenol content of 0.04%, a cumene content of 0.13%, and a heavy component content of 1.56%. The acetophenone recovery rate was 78.6%.

[0084] The purity (by mass fraction) of the cumene product obtained by the above method was 99.77%; the recovery rate of cumene was 100.00%.

[0085]

Example 3

[0086] The same steps as in Example 2 were used to recover cumene and produce acetophenone, except that the process parameters were changed. The specific parameters and the resulting product parameters are shown in Tables 1 and 2.

[0087]

Example 4

[0088] The same steps as in Example 2 were used to recover cumene and produce acetophenone, except that the process parameters were changed. The specific parameters and the resulting product parameters are shown in Tables 1 and 2.

[0089]

Example 5

[0090] The same steps as in Example 2 were used to recover cumene and produce acetophenone, except that the process parameters were changed. The specific parameters and the resulting product parameters are shown in Tables 1 and 2.

[0091]

Example 6

[0092] The same steps as in Example 2 were used to recover cumene and produce acetophenone, except that the process parameters were changed. The specific parameters and the resulting product parameters are shown in Tables 1 and 2.

[0093] Table 1 Product parameters of Examples 3-6

[0094]

[0095] Table 2 Product parameters of Examples 3-6

[0096]

[0097]

[0098]

Comparative Example 1

[0099] The system used is as shown in Example 1, except that the operating pressure of the cumene recovery tower is 40 kPaA, which is different from that in Example 4.

[0100] [Comparative Example 2]

[0101] The system shown in Example 1 was used, except that in Example 4, the acetophenone recovery tower collected the acetophenone product from position 5 (from top to bottom) of the theoretical plate number.

[0102] The product parameters obtained from the above comparative examples are shown in Table 3.

[0103] Table 3 Product parameters for comparative examples

[0104]

[0105] From the results in Tables 2 and 3, and by comparing Example 4 and Comparative Example 1, it can be seen that excessively high operating pressure in the cumene recovery tower will cause a significant reduction in the purity of the acetophenone product, and at the same time, the yield of the acetophenone product will also decrease to some extent.

[0106] The comparison between Example 4 and Comparative Example 2 shows that acetophenone can be obtained with a relatively high concentration and recovery rate by extracting acetophenone from the side stream of the acetophenone recovery tower.

[0107] In summary, this invention has discovered that phenol can also form a low-boiling-point azeotrope with cumene. Therefore, by distilling in the cumene recovery tower, the low-boiling-point azeotrope formed by phenol and cumene is collected from the top of the cumene recovery tower, while the heavy component containing acetophenone is collected from the bottom. This then enters the acetophenone recovery tower. In the acetophenone recovery tower, the material whose main component is cumene is collected from the top and recycled back to the cumene recovery tower, while the heavy component whose main component is cumene is collected from the bottom. The acetophenone product with a relatively high concentration is obtained by collecting from the side stream.

[0108] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0109] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0110] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0111] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. A process for cumene recovery and co-production of acetophenone, characterized by, Includes the following steps: (1) The material to be treated containing cumene, phenol and acetophenone is distilled, and the cumene product is collected from the top of the column and the heavy component containing acetophenone is collected from the bottom of the column. (2) Further distill the heavy component I containing acetophenone, collect the circulating stream from the top of the column and optionally return it to step (1) for distillation together with the material to be processed, collect the heavy component II from the bottom of the column, and collect the acetophenone product from the side stream of the column.

2. The method for recovering cumene and co-producing acetophenone according to claim 1, characterized in that: The materials to be processed include cumene, phenol, acetophenone, and heavy components; Preferably, by mass fraction, the material to be treated comprises 95%-99.5% cumene, 0.01%-1.0% phenol, 0.1%-3% acetophenone, and 0.01%-3% heavy components; More preferably, the material to be processed comes from the cumene recovery unit of the propylene oxide production process using the cumene peroxide method.

3. The method for recovering cumene and co-producing acetophenone according to claim 1, characterized in that: Step (1), The operating pressure at the top of the distillation column is 50-310 kPaA; preferably 51-300 kPaA; more preferably 51-200 kPaA; even more preferably 59-200 kPaA; still more preferably 100-200 kPaA; still more preferably 160-200 kPaA; and / or, The operating temperature at the top of the distillation column is 125-200℃; preferably 150-180℃.

4. The method for recovering cumene and co-producing acetophenone according to claim 1, characterized in that: Step (1), The reboiler operating temperature of the distillation column is 140-240℃; preferably 150-200℃; and / or, The theoretical plate number of the distillation is 20-80; preferably 30-50.

5. The method for recovering cumene and co-producing acetophenone according to claim 1, characterized in that: Step (2), The operating pressure at the top of the column for further distillation is 1-30 kPaA; preferably 3-20 kPaA; more preferably 5-20 kPaA; and / or, The operating temperature at the top of the distillation column is 40-110°C; preferably 50-100°C; more preferably 60-100°C; and / or, The reboiler operating temperature for further distillation is 140-240℃; preferably 160-215℃; and more preferably 160-200℃.

6. The method for recovering cumene and co-producing acetophenone according to claim 1, characterized in that: Step (2), The theoretical plate number for further distillation is 15-50; preferably 15-40; and / or, Acetophenone is collected from the side stream of the stripping section of the column; preferably, it is collected at a theoretical plate number of 10-40; more preferably, it is collected at a theoretical plate number of 15-40; and / or, The extracted acetophenone product is a gas phase product, and preferably the extracted acetophenone product stream contains ≤5wt% phenol, more preferably ≤1wt% phenol.

7. A system for recovering cumene and co-producing acetophenone, comprising, in sequence with the feed, a cumene recovery tower and an acetophenone recovery tower: The bottom outlet of the cumene recovery tower is connected to the inlet of the acetophenone recovery tower; the top outlet of the acetophenone recovery tower is optionally connected to the circulating material inlet of the cumene recovery tower; the stripping section of the acetophenone recovery tower is also equipped with a side stream material outlet. The system described in the method for recovering cumene and producing acetophenone according to any one of claims 1-6 is preferred.

8. The system for cumene recovery and co-production of acetophenone according to claim 7, characterized in that: The cumene recovery tower and the acetophenone recovery tower are each independently distillation towers; and / or, The cumene recovery tower has a side feed inlet; and / or, The top of the cumene recovery tower is provided with an isopropylbenzene product outlet; and / or, The acetophenone recovery tower is also equipped with a bottom outlet.

9. The system for cumene recovery and co-production of acetophenone according to claim 7, characterized in that: The reflux ratio of the cumene recovery tower is 0.05-2, preferably 0.1-1; more preferably 0.1-0.5; and / or, The reflux ratio of the acetophenone recovery tower is 0.1-2, preferably 0.5-2.

10. The system for cumene recovery and co-production of acetophenone according to claim 7, characterized in that: The cumene recovery tower has a feed inlet at 10-40 theoretical trays; preferably, it has a feed inlet at 15-30 theoretical trays. The acetophenone recovery tower has a feed inlet at a theoretical plate number of 5-30, preferably at a theoretical plate number of 5-20.

11. The use of the method according to any one of claims 1-6 or the system according to any one of claims 7-10 in the recovery of cumene and co-production of acetophenone.

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