Waste heat recovery device for ethyl acetate production

Abstract

The waste heat recovery device for ethyl acetate production comprises an esterification kettle, an esterification tower and a dehydration tower, the top of the esterification kettle is connected with the esterification tower through a material conveying pipe, and the tower top of the esterification tower is connected with a refining tower heat exchanger and a dehydration tower heat exchanger through esterification gas phase pipes. Liquid outlet ends of the refining tower heat exchanger and the dehydrating tower heat exchanger are connected with an esterification condenser through cooling pipes, one side of the dehydrating tower is connected with the refining tower through a discharging pipe, and a steam outlet of the dehydrating tower heat exchanger is connected with a dehydrating reboiler of the dehydrating tower through a first heat transfer pipeline. A steam outlet of the refining tower heat exchanger is connected with a refining reboiler of the refining tower through a second heat transfer pipeline, the temperature of a gas-phase material at the top of the esterification tower is up to 106 DEG C, heat of the gas-phase material at the top of the esterification tower is recovered through the refining tower heat exchanger and the dehydrating tower heat exchanger, and then heat is supplied to the dehydrating tower and the refining tower respectively; and heat exchange is realized for waste heat recovery.

Description

Technical Field

[0001] The utility model relates to the technical field of ethyl acetate production, in particular to a waste heat recovery device for ethyl acetate production. Background Art

[0002] Ethyl acetate, also known as ethyl acetate, has excellent solubility and quick drying properties. It is mainly used in industry to produce solvents for coatings, adhesives, ethyl cellulose, artificial leather, linoleum colorants and artificial fibers. It is also widely used in the production of printing, medicine, flavors and fragrances.

[0003] In the esterification process of producing ethyl acetate, ethyl acetate generated by the reaction of acetic acid and ethanol in the esterification kettle carries the generated water and part of the raw material ethanol, and rises to the top of the esterification tower in the form of a ternary azeotrope. After condensation, the mixed liquid is separated into layers by a phase separator, and the upper ethyl acetate overflows into the crude ester tank, and the lower water is sent to the wastewater recovery system. The temperature of the gas phase material at the top of the esterification tower is relatively high, and it needs to be cooled before subsequent production can be carried out. Using a condenser for cooling treatment is not only ineffective, but also directly discharges heat, causing a waste of energy. Utility Model Content

[0004] The purpose of the present application is to provide a waste heat recovery device for ethyl acetate production, so as to solve the problem that in the process of producing ethyl acetate by esterification, the temperature of the gas phase material at the top of the esterification tower is relatively high and needs to be cooled before subsequent production can be carried out. The cooling treatment using a condenser is not only ineffective, but also directly discharges heat, resulting in a waste of energy.

[0005] In order to solve the above technical problems, the present application provides a waste heat recovery device for ethyl acetate production, comprising an esterification kettle, an esterification tower and a dehydration tower, wherein an esterification reboiler is arranged on one side of the top of the esterification kettle, a feed pipe is arranged on one side of the esterification kettle, the top of the esterification kettle is connected to the esterification tower through a feed pipe, an esterification collector is arranged on the feed pipe, the top of the esterification tower is respectively connected to a refining tower heat exchanger and a dehydration tower heat exchanger through an esterification gas phase pipe, the liquid outlet ends of the refining tower heat exchanger and the dehydration tower heat exchanger are connected to an esterification condenser through a cooling pipe, and the other end of the esterification condenser is connected to an esterification Phase separator, one side of the top surface of the esterification phase separator is connected with an ester phase delivery pipe, the other end of the ester phase delivery pipe is connected with a dehydration feed phase separator, the top of the dehydration feed phase separator is connected with the dehydration tower through a dehydration delivery pipe, the top of the dehydration tower is connected with a dehydration condenser through a dehydration gas phase pipe, the outlet end of the dehydration condenser is connected with a dehydration tower top phase separator, the top of the dehydration tower top phase separator is connected with a light component tank through a discharge pipe, one side of the dehydration tower is connected with a refining tower through a discharge pipe, the steam outlet of the dehydration tower heat exchanger is connected with the dehydration reboiler of the dehydration tower through a first heat transfer pipe. The steam outlet of the refining tower heat exchanger is connected with the refining reboiler of the refining tower through a second heat transfer pipe.

[0006] Preferably, a raw material preheater is provided on the feed pipe.

[0007] Preferably, a circulation pipe is connected to the bottom end of the esterification kettle, the other end of the circulation pipe is communicated with the esterification reboiler, and an esterification kettle circulation pump is arranged on the circulation pipe.

[0008] Preferably, one end of the circulation pipe is connected to a bottom acid tank via a bottom acid discharge pipe, and a bottom acid condenser is provided on the bottom acid discharge pipe.

[0009] Preferably, the refining tower heat exchanger and the dehydration tower heat exchanger are both thermally coupled heat exchangers.

[0010] Preferably, a crude ester buffer tank is provided on the ester phase conveying pipe, and a dehydration tower buffer tank is provided between the dehydration condenser and the dehydration tower top phase separator.

[0011] Preferably, one end of the refining tower heat exchanger and the dehydration tower heat exchanger are both connected to a process water inlet pipe, and a water cooler is provided on the process water inlet pipe.

[0012] Preferably, an esterification reflux pipe is provided between the esterification tower and the ester phase conveying pipe.

[0013] Preferably, a dehydration reflux pipe is provided between the dehydration tower and the discharge pipe.

[0014] Compared with the prior art, the waste heat recovery device for ethyl acetate production provided by the utility model has at least the following beneficial effects:

[0015] 1. The temperature of the gas phase material at the top of the esterification tower is as high as 106°C. The heat of the gas phase material at the top of the esterification tower is recovered through the refining tower heat exchanger and the dehydration tower heat exchanger, and then the dehydration tower and the refining tower are heated respectively. The waste heat is collected and reused to achieve heat exchange and waste heat recovery, while reducing the impact of the heat discharged from the esterification gas phase material on the environment;

[0016] 2. The feed temperature of the esterification phase separator needs to be set at about 40°C. The esterification gas phase material is first cooled by heat exchange in the refining tower heat exchanger and the dehydration tower heat exchanger, and then cooled by the esterification condenser, which improves the condensation efficiency of the esterification condenser and achieves a better condensation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without inventiveness.

[0018] Figure 1 A schematic diagram of the structure of a waste heat recovery device for ethyl acetate production provided by the utility model;

[0019] In the figure: 1, esterification kettle; 2, esterification reboiler; 3, circulation pipe; 4, esterification kettle circulation pump; 5, bottom acid discharge pipe; 6, bottom acid tank; 7, bottom acid condenser; 8, feed pipe; 9, raw material preheater; 10, feed pipe; 11, esterification collector; 12, esterification tower; 13, esterification gas phase pipe; 14, refining tower heat exchanger; 15, dehydration tower heat exchanger; 16, cooling pipe; 17, esterification condenser; 18, esterification phase separator; 19, ester phase delivery pipe; 20, crude ester buffer tank ; 21. esterification reflux pipe; 22. dehydration feed phase separator; 23. dehydration conveying pipe; 24. dehydration tower; 25. first heat transfer pipeline; 26. dehydration reboiler; 27. dehydration gas phase pipe; 28. dehydration condenser; 29. ​​dehydration tower buffer tank; 30. dehydration tower top phase separator; 31. discharge pipe; 32. dehydration reflux pipe; 33. refining tower; 34. light component tank; 35. second heat transfer pipeline; 36. refining reboiler; 37. process water inlet pipe; 38. water cooler. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0021] The core of the present application is to provide a waste heat recovery device for ethyl acetate production, which solves the problem that in the esterification process for producing ethyl acetate, the temperature of the gas phase material at the top of the esterification tower is relatively high and needs to be cooled before subsequent production can be carried out. The cooling treatment using a condenser is not only ineffective, but also directly discharges heat, resulting in a waste of energy.

[0022] Figure 1 For the schematic diagram of the structure of a waste heat recovery device for ethyl acetate production provided by the utility model, see Figure 1 shown.

[0023] A waste heat recovery device for ethyl acetate production comprises an esterification kettle 1, an esterification tower 12 and a dehydration tower 24. An esterification reboiler 2 is arranged on one side of the top of the esterification kettle 1. The esterification kettle 1 is heated by the esterification reboiler 2. The structure and working principle of the esterification kettle 1 can refer to the prior art. A feed pipe 8 is arranged on one side of the esterification kettle 1. Acetic acid, ethyl ester and head ester (a mixture of ethanol, ethyl ester and water) are metered by a flow meter and added into the esterification kettle 1 through the feed pipe 8. The top of the esterification kettle 1 is connected to the esterification tower 12 through a feed pipe 10. Under the action of a catalyst, the esterification reboiler 2 is heated to generate ethyl acetate and water. An esterification trap 11 is provided on the feed pipe 10, and the formed ternary azeotrope is transported to the esterification tower 12 through the esterification trap 11. The working principle of the esterification tower 12 refers to the prior art. The ternary azeotrope is evaporated from the top of the tower through the esterification tower 12. The top of the esterification tower 12 is respectively connected to the refining tower heat exchanger 14 and the dehydration tower heat exchanger 15 through the esterification gas phase pipe 13. The liquid outlet ends of the refining tower heat exchanger 14 and the dehydration tower heat exchanger 15 are connected to the esterification condenser 17 through the cooling pipe 16. During the esterification process of the esterification tower 12, the 106°C gas phase crude ethyl acetate material discharged from the esterification gas phase pipe 13 provided on the top of the esterification tower 12 is condensed through the refining tower heat exchanger 14 and the dehydration tower heat exchanger 15, and then cooled again through the esterification condenser 17, so that the gas phase crude ethyl acetate is condensed into liquid phase crude ethyl acetate at 40°C. The other end of the esterification condenser 17 is connected to an esterification phase separator 18, and the liquid crude ethyl acetate enters the esterification phase separator 18, and the ester phase and the aqueous phase are separated by the esterification phase separator 18, and the aqueous phase is discharged into the recovery tower to recover the ethanol and ethyl ester dissolved in the water. An ester phase delivery pipe 19 is provided on one side of the top surface of the esterification phase separator 18, and the other end of the ester phase delivery pipe 19 is connected to the dehydration feed phase separator 22, and the separated crude ester phase is discharged into the ester phase delivery pipe 19. Preferably, an esterification reflux pipe 21 is provided between the esterification tower 12 and the ester phase delivery pipe 19, and a part of the ester phase returns to the esterification tower 12 as a tower top reflux, and the remaining ester phase is mixed with process water and enters the dehydration feed phase separator 22, and the ester phase and the aqueous phase are separated again after passing through the dehydration feed phase separator 22. The top of the dehydration feed phase separator 22 is connected to the dehydration tower 24 through the dehydration conveying pipe 23. The ester phase enters the dehydration tower 24 through the dehydration conveying pipe 23, and the water phase is conveyed to the dehydration tower top phase separator 30.

[0024] The top of the dehydration tower 24 is connected to a dehydration condenser 28 through a dehydration gas phase pipe 27, and the steam outlet of the dehydration tower heat exchanger 15 is connected to the dehydration reboiler 26 of the dehydration tower 24 through a first heat transfer pipe 25. When the dehydration tower heat exchanger 15 condenses and exchanges heat with the gas phase material at the top of the esterification tower 12, the heat recovered is supplied to the dehydration tower 24 through the first heat transfer pipe 25, thereby realizing heat recovery and reuse. During the heating process of the dehydration tower 24, the gas phase at the top of the dehydration tower 24 is condensed and cooled by the dehydration condenser 28, and the outlet end of the dehydration condenser 28 is connected to the dehydration tower top phase separator 30, and the top of the dehydration tower top phase separator 30 is connected to the light component tank through the discharge pipe 31. The condensed and cooled materials enter the dehydration tower top phase separator 30 for separation, and the obtained ester phase part goes to the light component tank. Preferably, a dehydration reflux pipe 32 is provided between the dehydration tower 24 and the discharge pipe 31, and part of the ester phase returns to the dehydration tower 24 as reflux, and the water phase is discharged into the recovery tower to recover the ethanol and ethyl ester dissolved in the water. One side of the dehydration tower 24 is connected to the refining tower 33 through the discharge pipe, and the crude product with qualified acidity, moisture and content obtained in the dehydration tower 24 is discharged into the refining tower 33 for distillation to obtain a qualified ethyl acetate product, and the steam outlet of the refining tower heat exchanger 14 is connected to the refining reboiler 36 of the refining tower 33 through the second heat transfer pipeline 35. When the refining tower heat exchanger 14 condenses and exchanges heat for the gaseous material at the top of the esterification tower 12, the recovered heat is supplied to the refining tower 33 through the second heat transfer pipe 35, thereby realizing heat recovery and repeated utilization.

[0025] In this embodiment, in order to improve the working efficiency of the esterification kettle 1 and achieve better results, preferably, a raw material preheater 9 is provided on the feed pipe 8, and various raw materials are preheated and then added to the esterification kettle 1, which can accelerate the esterification reaction of various raw materials and improve the esterification efficiency. Preferably, a circulation pipe 3 is connected to the bottom end of the esterification kettle 1, and the other end of the circulation pipe 3 is connected to the esterification reboiler 2. An esterification kettle circulation pump 4 is provided on the circulation pipe 3, and the esterification materials are circulated by the esterification kettle circulation pump 4 to improve the esterification reaction rate.

[0026] In order to conveniently discharge the bottom acid formed in the esterification kettle 1, preferably, one end of the circulation pipe 3 is connected to the bottom acid tank 6 through the bottom acid discharge pipe 5, and the bottom acid discharge pipe 5 is provided with a bottom acid condenser 7. The high-temperature bottom acid is cooled by the bottom acid condenser 7 and then discharged into the bottom acid tank 6 for collection.

[0027] In order to further achieve better waste heat recovery effect, preferably, the refining tower heat exchanger 14 and the dehydration tower heat exchanger 15 are both thermally coupled heat exchangers. The thermally coupled heat exchanger is a highly efficient gas-liquid heat recovery device. There will be no cross leakage between the gas and the supplied liquid material in the thermally coupled heat exchanger, and the hot fluid and the cold fluid are completely separated, which is safe and reliable and reduces energy loss.

[0028] In this embodiment, in order to protect the esterification device, preferably, a crude ester buffer tank 20 is provided on the ester phase delivery pipe 19 to prevent the delivery pump on the ester phase delivery pipe 19 from being evacuated, and a dehydration tower buffer tank 29 is provided between the dehydration condenser 28 and the dehydration tower top phase separator 30, and the esterification device is also protected by the dehydration tower buffer tank 29.

[0029] Preferably, in order to exchange heat for the gas phase material at the top of the esterification tower 12, one end of the refining tower heat exchanger 14 and the dehydration tower heat exchanger 15 are both connected to the process water inlet pipe 37, and a water cooler 38 is provided on the process water inlet pipe 37 to improve the heat exchange effect.

[0030] The waste heat recovery device for ethyl acetate production provided in the present application has the following working principle: acetic acid, ethyl ester and head ester (a mixture of ethanol, ethyl ester and water) are metered by a flow meter and added to the esterification kettle 1 through a feed pipe 8, and heated by an esterification reboiler 2 under the action of a catalyst to generate ethyl acetate and water. The formed ternary azeotrope is transported to the esterification tower 12 through an esterification trap 11, and the 106°C gas phase crude ethyl acetate material discharged from the esterification gas phase pipe 13 arranged at the top of the esterification tower 12 is condensed by heat exchange in a refining tower heat exchanger 14 and a dehydration tower heat exchanger 15, and then cooled again by an esterification condenser 17, so that the gas phase crude ethyl acetate is condensed into a 40°C liquid phase crude ethyl acetate. The liquid crude ethyl acetate enters the esterification phase separator 18, and the ester phase and the water phase are separated by the esterification phase separator 18. A part of the ester phase returns to the esterification tower 12 as the top reflux, and part of the ester phase enters the dehydration tower 24. The heat recovered by the dehydration tower heat exchanger 15 during condensation and heat exchange of the gas phase material at the top of the esterification tower 12 is supplied to the dehydration tower 24 through the first heat transfer pipe 25, thereby realizing heat recovery and reuse. During the heating process of the dehydration tower 24, the gas phase at the top of the dehydration tower 24 is condensed and cooled by the dehydration condenser 28, and the condensed and cooled material enters the phase separator 30 at the top of the dehydration tower for separation, and the obtained ester phase is partially removed to the light component tank, and part of the ester phase returns to the dehydration tower 24 as reflux. The crude product with qualified acidity, moisture and content obtained in the dehydration tower 24 is discharged into the refining tower 33 for distillation to obtain a qualified ethyl acetate product. The heat recovered when the refining tower heat exchanger 14 condenses and exchanges heat with the gas phase material at the top of the esterification tower 12 is supplied to the refining tower 33 through the second heat transfer pipe 35, thereby realizing heat recovery and reuse.

[0031] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art disclosed in the present application. The specification and examples are to be regarded as exemplary only, and the true scope of the present application is indicated by the claims.

[0032] It should be understood that the present application is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The above-described embodiments of the present application do not constitute a limitation on the scope of protection of the present application.

Claims

1. A waste heat recovery device for ethyl acetate production, characterized in that: include: An esterification kettle (1), an esterification tower (12) and a dehydration tower (24), wherein an esterification reboiler (2) is arranged on one side of the top of the esterification kettle (1), a feed pipe (8) is arranged on one side of the esterification kettle (1), the top of the esterification kettle (1) is connected to the esterification tower (12) via a feed pipe (10), an esterification collector (11) is arranged on the feed pipe (10), and the top of the esterification tower (12) is connected to the esterification tower (12) via an esterification gas phase pipe (11). 3) are respectively connected to a refining tower heat exchanger (14) and a dehydration tower heat exchanger (15); the liquid outlet ends of the refining tower heat exchanger (14) and the dehydration tower heat exchanger (15) are connected to an esterification condenser (17) through a cooling pipe (16); the other end of the esterification condenser (17) is connected to an esterification phase separator (18); one side of the top surface of the esterification phase separator (18) is connected to an ester phase delivery pipe (19); the ester phase delivery pipe The other end of (19) is connected to a dehydration feed phase separator (22), the top of the dehydration feed phase separator (22) is connected to the dehydration tower (24) through a dehydration delivery pipe (23), the top of the dehydration tower (24) is connected to a dehydration condenser (28) through a dehydration gas phase pipe (27), the outlet end of the dehydration condenser (28) is connected to a dehydration tower top phase separator (30), the top of the dehydration tower top phase separator (30) is connected to the dehydration tower top phase separator (30) through a dehydration gas phase pipe (27). The discharge pipe (31) is connected to a light component tank, one side of the dehydration tower (24) is connected to a refining tower (33) via a discharge pipe, the steam outlet of the dehydration tower heat exchanger (15) is connected to the dehydration reboiler (26) of the dehydration tower (24) via a first heat transfer pipe (25), and the steam outlet of the refining tower heat exchanger (14) is connected to the refining reboiler (36) of the refining tower (33) via a second heat transfer pipe (35).

2. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: The feed pipe (8) is provided with a raw material preheater (9).

3. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: The bottom end of the esterification kettle (1) is connected to a circulation pipe (3), the other end of the circulation pipe (3) is in communication with the esterification reboiler (2), and the circulation pipe (3) is provided with an esterification kettle circulation pump (4).

4. The waste heat recovery device for ethyl acetate production according to claim 3, characterized in that: One end of the circulation pipe (3) is connected to a bottom acid tank (6) via a bottom acid discharge pipe (5), and a bottom acid condenser (7) is provided on the bottom acid discharge pipe (5).

5. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: The refining tower heat exchanger (14) and the dehydration tower heat exchanger (15) are both thermally coupled heat exchangers.

6. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: A crude ester buffer tank (20) is provided on the ester phase delivery pipe (19), and a dehydration tower buffer tank (29) is provided between the dehydration condenser (28) and the dehydration tower top phase separator (30).

7. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: One end of the refining tower heat exchanger (14) and the dehydration tower heat exchanger (15) are both connected to a process water inlet pipe (37), and a water cooler (38) is provided on the process water inlet pipe (37).

8. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: An esterification reflux pipe (21) is provided between the esterification tower (12) and the ester phase delivery pipe (19).

9. The waste heat recovery device for ethyl acetate production according to claim 1, characterized in that: A dehydration reflux pipe (32) is provided between the dehydration tower (24) and the discharge pipe (31).

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