Coupling process and system for cumene refining and low temperature concentration of hydrogen peroxide cumene

Abstract

The application discloses a coupling method and system for cumene refining and low-temperature concentration of cumene hydroperoxide, wherein the coupling method for cumene refining and low-temperature concentration of cumene hydroperoxide comprises the steps of refining cumene and low-temperature concentrating cumene hydroperoxide, and heat coupling is performed between the refining process of cumene and the refining process of cumene hydroperoxide by controlling the temperature and pressure of cumene refining and the temperature and pressure of cumene hydroperoxide concentration. The application realizes zero energy consumption in the concentration process, effectively establishes a low-temperature double-effect process, and simultaneously achieves the purposes of reducing product decomposition and energy consumption.

Description

Technical Field

[0001] This invention relates to the field of cumene hydrogen peroxide concentration technology, specifically to a coupled method and system for cumene purification and low-temperature concentration of cumene hydrogen peroxide. Background Technology

[0002] Cumene hydroperoxide is produced by alkylating cumene to form an intermediate component, which is then oxidized in air or oxygen. The preparation of cumene hydroperoxide requires the raw material cumene, which itself undergoes a purification process. Specifically, the cumene extraction process includes: 1. Further purification of cumene obtained from alkylation to produce cumene; 2. Further purification of cumene obtained from the synthesis of products such as propylene oxide. Although the composition of the raw materials and the controlled temperature and pressure of the distillation column differ in these two processes, the high boiling point of cumene means that both processes generate significant waste heat during purification.

[0003] Existing methods for concentrating cumene hydroperoxide typically involve distillation and flash evaporation under controlled negative pressure. However, in chemical production processes, concentrating cumene hydroperoxide at lower concentrations means distilling off a large amount of light components from the feedstock through distillation and flash evaporation processes at the top of the column. These existing methods are energy-intensive, representing one of the major energy-consuming nodes in the production unit. Furthermore, the aforementioned conventional methods also suffer from low yields. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of high energy consumption and low yield in the existing methods for concentrating cumene hydroperoxide, thereby providing a coupled method and system for cumene purification and low-temperature concentration of cumene hydroperoxide to solve the above problems.

[0005] A coupled method for cumene purification and low-temperature concentration of cumene hydroperoxide includes a step of cumene purification and a step of low-temperature concentration of cumene hydroperoxide.

[0006] The cumene is purified in a first distillation column, the top pressure of which is 30-90 kPaA and the temperature is 110-145℃.

[0007] The cumene hydroperoxide is concentrated at low temperatures in a second and a third distillation column. The top pressure of the second distillation column is 6–18 kPaA, the top temperature is 70–95°C, and the bottom temperature is below 100°C. The top pressure of the third distillation column is 2–10 kPaA, the temperature is 44–80°C, and the bottom temperature of the third distillation column has a temperature difference of more than 7°C from the top temperature of the second distillation column.

[0008] The heat recovered at the top of the first distillation column is used as the reboiling heat source at the bottom of the second distillation column, and the heat of the gas at the top of the second distillation column is used as the reboiling heat source at the bottom of the third distillation column.

[0009] The second distillation column receives feed containing 5% to 50% cumene hydroperoxide by mass; the third distillation column receives the bottom product of the second distillation column as feed.

[0010] The concentration of cumene hydroperoxide in the product obtained at the bottom of the third distillation column is increased by more than 10%.

[0011] The coupled system based on the coupled method of cumene purification and low-temperature concentration of cumene hydroperoxide includes:

[0012] The first distillation column is used for the purification of cumene, obtaining the cumene stream at the top of the column and the heavy components at the bottom of the column.

[0013] The second distillation column is used for the low-temperature concentration of cumene hydroperoxide and includes a second distillation column reboiler; the heat from the cumene at the top of the first distillation column is thermally coupled with the heat from the second distillation column reboiler.

[0014] The third distillation column includes a third distillation column reboiler, and the bottom stream of the second distillation column is used as the feed for the third distillation column; the heat of the top gas of the second distillation column is thermally coupled with the reboiler of the third distillation column.

[0015] The bottom of the first distillation column is equipped with a first distillation column reboiler and a first distillation column self-coupling reboiler;

[0016] The cumene at the top of the first distillation column is condensed in the condenser at the top of the first distillation column and then enters the reflux tank at the top of the first distillation column. It is then refluxed or collected by the reflux pump at the top of the first distillation column. The cold-side flow medium in the condenser at the top of the first distillation column is vaporized into steam. Part of the steam enters the reboiler of the second distillation column for heat exchange, and the remaining part enters the compressor for compression and then undergoes heat coupling with the self-coupling reboiler of the first distillation column.

[0017] The overhead stream from the second distillation column is condensed in the reboiler of the third distillation column, then enters the reflux tank of the second distillation column and is either refluxed or collected by the reflux pump of the second distillation column.

[0018] The overhead stream of the second distillation column is also connected to the condenser of the second distillation column, and the stream condensed in the condenser of the second distillation column enters the reflux tank of the second distillation column.

[0019] The overhead stream of the third distillation column is condensed and cooled by the condenser of the third distillation column and then enters the reflux tank of the third distillation column, where it is either refluxed or extracted by the reflux pump of the third distillation column.

[0020] The bottom of the third distillation column is connected to an external heat source reboiler.

[0021] The first, second, and third distillation columns are all connected to the control system for pressure control.

[0022] The technical solution of this invention has the following advantages:

[0023] 1. The coupling method for cumene purification and low-temperature concentration of cumene hydroperoxide provided by the present invention includes a step of cumene purification and a step of low-temperature concentration of cumene hydroperoxide. By controlling the temperature and pressure of cumene purification and the temperature and pressure of cumene hydroperoxide concentration, the purification process of cumene and the purification process of cumene hydroperoxide are thermally coupled and integrated, so that the concentration process does not require an external heat source and can be carried out with zero energy consumption. This effectively establishes a low-temperature dual-effect process and simultaneously achieves the goals of high yield and low energy consumption.

[0024] Specifically, this invention controls the temperature and pressure of cumene refining to achieve the desired cumene refining effect while effectively providing energy for the reboiling process of low-temperature concentration of cumene hydroperoxide, thus enabling the concentration process to be carried out with zero energy consumption. Furthermore, the concentration of cumene hydroperoxide utilizes the coordinated temperature and pressure of the second and third distillation columns, significantly reducing energy consumption. Simultaneously, based on the thermosensitive and easily decomposed characteristics of cumene hydroperoxide, this invention controls the temperatures of both the second and third distillation columns below 100°C, enabling the concentration process to be carried out at low temperatures. The overall temperature can be below the flash point of the peroxide, improving safety and reducing the generation of byproducts and the decomposition rate of the peroxide, thereby ensuring yield.

[0025] 2. The coupling system for cumene refining and low-temperature concentration of cumene hydroperoxide provided by the present invention, through structural optimization, especially the setting of the reboiler of the first distillation column, the external heat source steam, and the external heat source reboiler of the third distillation column, can achieve independent operation of each column under abnormal operating conditions, thereby improving stability; the system of the present invention can ultimately achieve a high-efficiency operation process with low energy consumption, low material cost, and high stability. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the coupling system in this invention.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1- First distillation column reboiler; 2- First distillation column; 3- First distillation column overhead condenser; 4- First distillation column overhead reflux tank; 5- First distillation column reflux pump; 6- First distillation column self-coupling reboiler; 7- Second distillation column reboiler; 8- Second distillation column; 9- Second distillation column reflux tank; 10- Second distillation column reflux pump; 11- Third distillation column reboiler; 12- Compressor; 13- Third distillation column; 14- Third distillation column condenser; 15- Third distillation column reflux tank; 16- Third distillation column reflux pump; 17- Second distillation column condenser; 18- Third distillation column external heat source reboiler; 19- External heat source; 20- Control system. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Example 1

[0035] A coupled system for the purification of cumene and the low-temperature concentration of cumene hydroperoxide, such as Figure 1As shown, it includes: a first distillation column 2 for refining cumene, obtaining cumene stream at the top of the column and heavy components at the bottom; a second distillation column 8 for low-temperature concentration of cumene hydroperoxide, including a second distillation column reboiler 7; the heat of cumene at the top of the first distillation column 2 is thermally coupled with the heat of the second distillation column reboiler 7; and a third distillation column 13, including a third distillation column reboiler 11, with the bottom stream of the second distillation column 8 serving as the feed to the third distillation column 13; the heat of the gas at the top of the second distillation column 8 is thermally coupled with the heat of the third distillation column reboiler 11.

[0036] This invention, through the above-mentioned structural design, combines temperature and pressure control with distillation column parameter regulation to achieve low-temperature concentration, and uses a dual-tower, dual-effect process for product recovery and energy coupling to achieve energy saving, consumption reduction, and improved stability and safety.

[0037] The specific structural layout and connection relationships of each distillation column are as follows:

[0038] Raw materials containing heavy components, cumene, and other light components enter the cumene refining system;

[0039] In the first distillation column 2, after purification, the top and bottom of the column respectively yield cumene containing a small amount of light components and heavy components containing benzyl alcohol. The cumene from the top of the first distillation column 2 is condensed by the first distillation column top condenser 3 and then enters the first distillation column top reflux tank 4, and is either refluxed or collected by the first distillation column reflux pump 5. The cold-side stream medium in the first distillation column top condenser 3 is vaporized into steam. Part of the steam enters the second distillation column reboiler 7 for heat exchange, and the remaining part enters the compressor 12 for compression and then undergoes heat coupling with the first distillation column self-coupling reboiler 6. The medium from the compressor 12 enters the first distillation column self-coupling reboiler 6, which, together with the first distillation column reboiler 1 which uses an external medium as a heat source, provides a distillation heat source for the first distillation column 2.

[0040] The second distillation column 8 receives a feedstock containing cumene hydroperoxide, heavy components, and light components of cumene hydroperoxide. After purification, the top and bottom of the column yield light components and cumene hydroperoxide containing heavy components of cumene and benzyl alcohol, respectively. The top stream of the second distillation column 8 enters the reboiler 11 of the third distillation column for condensation and then enters the reflux tank 9 of the second distillation column, where it is either refluxed or collected by the reflux pump 10. The bottom stream of the second distillation column 8 serves as the feed for the third distillation column 13. The second distillation column 8 is heated by the reboiler 7, and the heat source medium for the reboiler 7 is provided by the vapor produced from the cumene stream at the top of the first distillation column 2.

[0041] The third distillation column 13 is heated by the third distillation column reboiler 11. Its feed is the bottom stream of the second distillation column 8, i.e., the bottom product of the second distillation column 8; the top stream of the third distillation column 13 is condensed and cooled by the third distillation column condenser 14 and then enters the third distillation column reflux tank 15 and is refluxed or collected by the third distillation column reflux pump 16.

[0042] The coupling system of this invention includes a control system 20 that controls various parameters of the process. The control system 20 regulates the pressure and temperature of the first distillation column 2, the second distillation column 8, and the third distillation column 13 to keep the parameters within the target range. The system also includes the regulation of the heat source flow rate of each column. Specifically, the pressure of the first distillation column 2, the second distillation column 8, and the third distillation column 13 is controlled by a non-condensable vapor extraction system and a cryogenic heat exchanger is set according to the properties of the material. The pressure control method is to extract the non-condensable gas obtained from the reflux tank through a vacuum pump to control all three columns to be in a vacuum state.

[0043] The pressure and temperature control ranges and characteristics of each tower are as follows:

[0044] The top pressure of the first distillation column 2 is controlled within the range of 30–90 kPaA, and the temperature range is 110–145 °C. The heat generated by the hot flow at the top of the column is removed by using condensate or boiler water to generate low-pressure or negative-pressure steam, which is preferentially supplied to the second distillation column reboiler 7 of the second distillation column 8 after the column pressure is regulated and there is a sufficient heat exchange temperature difference. The excess heat is pressurized to 150–700 kPaA by the compressor and then used as its own heat source.

[0045] The top pressure of the second distillation column 8 is controlled within the range of 6 to 18 kPaA, the temperature range is 70 to 95°C, and the top operating temperature is controlled below 100°C to ensure that its hydroperoxide isopropylbenzene product does not decompose in large quantities. At the same time, it has the conditions to use the heat recovered from the top of the first distillation column 2 as a reboiling heat source.

[0046] The top pressure of the third distillation column 13 is controlled within the range of 2–10 kPaA, and the temperature range is 44–80°C. Similarly, the temperature is controlled within the lower temperature range below 80°C. The control system 20 adjusts the bottom operating pressure of the third distillation column 13 so that its corresponding temperature has a temperature difference of more than 7°C with the top temperature of the second distillation column 8, so that heat exchange can be carried out between the two. At the same time, it ensures that the final product with a higher concentration of cumene peroxide has an extremely low decomposition rate. Preferably, it can be concentrated at a low temperature below the flash point of cumene peroxide to ensure its stability and safety.

[0047] In this invention, the second distillation column 8 receives a feed containing 5% to 50% cumene hydroperoxide by mass; the third distillation column 13 receives the bottom product of column 8 as feed, and the product obtained at the bottom of the column contains 15% to 60% cumene hydroperoxide by mass.

[0048] The three distillation columns, namely the first distillation column 2, the second distillation column 8, and the third distillation column 13, can be decoupled from each other and operate independently. The second distillation column 8 and the third distillation column 13 can operate simultaneously or not simultaneously. Specifically, the steam generated by the top condenser 3 of the first distillation column, except for the steam returning to the self-coupled reboiler 6 of the first distillation column, is connected to the steam of the external heat source 19. The steam in the external heat source 19 mixes with the steam generated by the top condenser 3 of the first distillation column to provide heat energy for the reboiler 7 of the second distillation column. The top stream of the second distillation column 8 is also connected to the second distillation column condenser 17. Next, the condensed stream in the second distillation column condenser 17 enters the second distillation column reflux tank 9; the bottom of the third distillation column 13 is connected to the external heat source reboiler 18, which is heated by an external heat source. The flow rate of the external heat source 19, as well as the hot-side and cold-side flow rates of the second distillation column condenser 17 and the third distillation column external heat source reboiler 18, are controlled by the control system 20; under the above pressure, temperature and heat exchange conditions, the second distillation column 8 and the third distillation column 13 can produce products with essentially the same quality as those produced during coupled heat exchange operation.

[0049] Example 2

[0050] The coupling method using the coupling system of cumene purification and low-temperature concentration of cumene hydroperoxide in Example 1 includes:

[0051] Cumene is distilled off from the top of the first distillation column 2. The feed to the second distillation column 8 is a 200 t / h cumene solution containing 5 wt% cumene hydroperoxide and dimethyl benzyl alcohol, among other heavy components. After distillation and concentration in the first column of the second distillation column 8 and the second column of the third distillation column 13, cumene is distilled off, and the concentration of cumene hydroperoxide is increased to 15 wt%. The control system controls the operating parameters of each column as follows:

[0052] First distillation column 2: 55 kPaA, top temperature 130℃; Second distillation column 8: 18 kPaA, top temperature 95℃, bottom temperature 100℃; Third distillation column 13: 10 kPaA, top temperature 80℃, bottom temperature 88℃. After operation, the reboiling load of the second distillation column 8 is 13.9 MW, and the reboiling load of the third distillation column 13 is 8.3 MW. The first distillation column 2 can meet the heat supply for the concentration system without the need for an external heat source. The concentration system operates at low temperature, and the energy consumption is low under the coupling of the three columns. The concentration of cumene hydroperoxide is 15%, and the top of the two concentration columns contains recycled cumene material. No obvious material polymerization or decomposition problems were observed in the product.

[0053] Example 3

[0054] The coupling method using the coupling system of cumene purification and low-temperature concentration of cumene hydroperoxide in Example 1 includes:

[0055] Cumene is distilled off from the top of the first distillation column 2. The feed to the second distillation column 8 is a 200 t / h cumene solution containing 20 wt% cumene hydroperoxide and heavy components such as dimethyl benzyl alcohol. After distillation and concentration in the first column of the second distillation column 8 and the second column of the third distillation column 13, cumene is distilled off, and the concentration of cumene hydroperoxide is increased to 30 wt%. The control system controls the operating parameters of each column as follows:

[0056] First distillation column 2: 47 kPaA, top temperature 126℃; Second distillation column 8: 13 kPaA, top temperature 87℃, bottom temperature 96℃; Third distillation column 13: 5 kPaA, top temperature 63℃, bottom temperature 78℃. After operation, the reboiling load of the second distillation column 8 is 9 MW, and the reboiling load of the third distillation column 13 is 4.2 MW. The first distillation column 2 can meet the heat supply for the concentration system without an external heat source. The concentration system operates at low temperature. The energy consumption is low under the coupling of the three columns. The concentration of cumene hydroperoxide product is 30%, and the top of the two concentration columns is recycled cumene material. There are no obvious problems with material polymerization and decomposition in the product.

[0057] Example 4

[0058] The coupling method using the coupling system of cumene purification and low-temperature concentration of cumene hydroperoxide in Example 1 includes:

[0059] Cumene is distilled off from the top of the first distillation column 2. The feed to the second distillation column 8 is a 200 t / h cumene solution containing 50 wt% cumene hydroperoxide and dimethyl benzyl alcohol, among other heavy components. After distillation and concentration in the first column of the second distillation column 8 and the second column of the third distillation column 13, cumene is distilled off, increasing the cumene hydroperoxide concentration to 60 wt%. The control system controls the operating parameters of each column as follows:

[0060] First distillation column 2: 52 kPaA, top temperature 128℃; Second distillation column 8: 10 kPaA, top temperature 80℃, bottom temperature 98℃; Third distillation column 13: 2 kPaA, top temperature 44℃, bottom temperature 73℃. After operation, the reboiling load of the second distillation column 8 is 7.6 MW, and the reboiling load of the third distillation column 13 is 2.4 MW. The first distillation column 2 can meet the heat supply for the concentration system without the need for an external heat source. The concentration system operates at low temperature, and the energy consumption is low under the coupling of the three columns. The concentration of cumene hydroperoxide product is 60%, and the top of the two concentration columns contains recycled cumene material. No obvious material polymerization or decomposition problems were observed in the product.

[0061] Example 5

[0062] The coupling method using the coupling system of cumene purification and low-temperature concentration of cumene hydroperoxide in Example 1 includes:

[0063] Cumene is distilled off from the top of the first distillation column 2. The feed to the second distillation column 8 is a 200 t / h cumene solution containing 10 wt% cumene hydroperoxide and dimethyl benzyl alcohol, among other heavy components. After distillation and concentration in the first column of the second distillation column 8 and the second column of the third distillation column 13, cumene is distilled off, and the concentration of cumene hydroperoxide is increased to 20 wt%. The control system controls the operating parameters of each column as follows:

[0064] First distillation column 2: 30 kPaA, top temperature 111℃; Second distillation column 8: 6 kPaA, top temperature 71℃, bottom temperature 81℃; Third distillation column 13: 2 kPaA, top temperature 44℃, bottom temperature 64℃. After operation, the reboiling load of the second distillation column 8 is 9.4 MW, and the reboiling load of the third distillation column 13 is 5.5 MW. The first distillation column 2 can meet the heat supply for the concentration system without the need for an external heat source. The concentration system operates at low temperature. The energy consumption is low under the coupling of the three columns. The concentration of cumene hydroperoxide product is 20%, and the top of the two concentration columns is recycled cumene material.

[0065] The products in Examples 2-5 did not show any obvious problems with material polymerization and decomposition.

[0066] Comparative Example 1

[0067] An apparatus for producing cumene hydroperoxide and its downstream products includes a cumene refining tower 2 and a cumene hydroperoxide concentration tower. The apparatus receives a 200 t / h cumene solution containing 20 wt% cumene hydroperoxide and heavy components such as dimethyl benzyl alcohol. The solution is then concentrated in a single distillation tower to remove cumene hydroperoxide and increase its concentration to 30 wt%. The concentration tower pressure is controlled at 13 kPaA, the top temperature at 87°C, and the bottom temperature at 97°C. The heat required to obtain the target product concentration is 38 MW.

[0068] The pressure of the first distillation column 2 is controlled at 22 kPaA and 101°C, and the heat cannot be effectively utilized as it is cooled by circulating water. The system has high energy consumption for circulating water and steam.

[0069] The difference between Examples 2 to 5 is that the control system regulates the pressure, required product concentration, and feed concentration of each distillation column differently. Correspondingly, the operating temperature and energy consumption differ, but they can still achieve stable and safe operation with low energy and low material consumption within the protection range. There are no obvious problems with material polymerization and decomposition in the product.

[0070] In Examples 2-5, regarding the distillation and concentration system itself, the energy efficiency of the second distillation column 8 and the third distillation column 13 is achieved by controlling the appropriate pressure within the protection range according to the concentration requirements of different products. Compared with Comparative Example 1, their energy efficiency can reach 25-40%. Furthermore, in conjunction with the cumene distillation system, by adjusting the pressure of the first distillation column 2, a stream with a temperature matching that of the concentration system is obtained through indirect heat exchange to provide reboiling steam for concentration, eliminating the need for external steam. Distillation and concentration, by controlling the temperature within a range not exceeding 100°C, is more conducive to heat exchange of heat-sensitive product streams. The yield of cumene hydroperoxide at the bottom of the columns obtained in all comparative examples and examples reached over 99%.

[0071] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A coupled method for cumene purification and low-temperature concentration of cumene hydroperoxide, comprising a step of cumene purification and a step of low-temperature concentration of cumene hydroperoxide; characterized in that, The cumene is purified in the first distillation column (2), where the top pressure of the first distillation column (2) is 30-90 kPaA and the temperature is 110-145℃. The hydroperoxide isopropylbenzene is concentrated at low temperature in the second distillation column (8) and the third distillation column (13) in sequence; the top pressure of the second distillation column (8) is 6-18 kPaA, the top temperature is 70-95℃, and the bottom temperature is below 100℃; the top pressure of the third distillation column (13) is 2-10 kPaA, the temperature is 44-80℃, and the bottom temperature has a temperature difference of more than 7℃ from the top temperature of the second distillation column (8); The heat recovered at the top of the first distillation column (2) is used as the reboiling heat source at the bottom of the second distillation column (8), and the heat of the gas at the top of the second distillation column (8) is used as the reboiling heat source at the bottom of the third distillation column (13).

2. The coupling method according to claim 1, characterized in that, The second distillation column (8) receives feed containing 5% to 50% cumene hydroperoxide by mass; the third distillation column (13) receives the bottom product of the second distillation column (8) as feed.

3. The coupling method according to claim 2, characterized in that, The concentration of cumene hydroperoxide in the product obtained at the bottom of the third distillation column (13) is increased by more than 10%.

4. A coupling system based on the coupling method according to any one of claims 1-3, characterized in that, include: The first distillation column (2) is used for the purification of cumene, to obtain the cumene stream at the top of the column and the heavy components at the bottom of the column. The second distillation column (8) is used for the low-temperature concentration of cumene hydroperoxide and includes a second distillation column reboiler (7); the heat of the cumene at the top of the first distillation column (2) is thermally coupled with the heat of the second distillation column reboiler (7). The third distillation column (13) includes a third distillation column reboiler (11), and the bottom stream of the second distillation column (8) is used as the feed for the third distillation column (13); the heat of the top gas of the second distillation column (8) is thermally coupled with the heat of the third distillation column reboiler (11).

5. The coupling system according to claim 4, characterized in that, The bottom of the first distillation column (2) is provided with a first distillation column reboiler (1) and a first distillation column self-coupling reboiler (6); The cumene at the top of the first distillation column (2) is condensed in the first distillation column top condenser (3) and then enters the first distillation column top reflux tank (4), and is refluxed or collected by the first distillation column reflux pump (5); the cold side of the material medium in the first distillation column top condenser (3) is vaporized into steam, part of which enters the second distillation column reboiler (7) for heat exchange, and the remaining part enters the compressor (12) for compression and then is thermally coupled with the first distillation column self-coupling reboiler (6).

6. The coupling system according to claim 4, characterized in that, The overhead stream from the second distillation column (8) is condensed in the reboiler (11) of the third distillation column, then enters the reflux tank (9) of the second distillation column and is either refluxed or extracted by the reflux pump (10) of the second distillation column.

7. The coupling system according to claim 6, characterized in that, The top stream of the second distillation column (8) is simultaneously connected to the second distillation column condenser (17), and the stream condensed in the second distillation column condenser (17) enters the second distillation column reflux tank (9).

8. The coupling system according to claim 4, characterized in that, The top stream of the third distillation column (13) is condensed and cooled by the third distillation column condenser (14) and then enters the third distillation column reflux tank (15) and is refluxed or extracted by the third distillation column reflux pump (16).

9. The coupling system according to claim 8, characterized in that, The bottom of the third distillation column (13) is connected to the external heat source reboiler (18).

10. The coupling system according to claim 9, characterized in that, The first distillation column (2), the second distillation column (8), and the third distillation column (13) are all connected to the control system (20) for pressure control.

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