Ethyl acetate synthesis method and device

Abstract

The invention relates to the technical field of ethyl acetate synthesis, in particular to an ethyl acetate synthesis method and device. Comprising the following steps: S1, synthesizing; s2, extracting; s3, refining; and S4, water distribution. The method has the beneficial effects that the extraction step is added at the reflux position at the top of the synthesis tower, so that the distillation amount and reflux amount of water are greatly reduced, the energy consumption is greatly reduced, and the energy-saving rate reaches 20-51%.

Description

Technical Field

[0001] The invention relates to the technical field of ethyl acetate synthesis, in particular to a method and a device for synthesizing ethyl acetate. Background Art

[0002] Ethyl acetate is a common chemical raw material. Its synthesis method mostly uses dehydration esterification of acetic acid and ethanol under the action of catalyst.

[0003] In the existing production process, it usually needs reaction, distillation, recycling and other steps to complete. The overall energy consumption is large and there are many reaction equipments.

[0004] Chinese patent application number 201511026285.7 discloses a production process of ethyl acetate, the steps of which are as follows:

[0005] 1. Using acetic acid and ethanol to react in countercurrent in a tower device to generate ethyl acetate;

[0006] 2. The crude product ethyl acetate at the top of the tower in step 1 enters the ester distillation tower for refining, and the product is obtained at the bottom of the tower. The substances generated at the top of the tower (containing water, ethanol, and a small amount of ethyl acetate) are returned to the tower equipment in step 1;

[0007] 3. The product at the bottom of the tower in step 1 (containing water and ethanol) enters a dehydration tower for dehydration, and the waste water obtained at the bottom of the tower is discharged, and the substance generated at the top of the tower (containing ethanol, a small amount of water and ethyl acetate) is returned to the tower equipment in step 1.

[0008] Although this method obtains ethyl acetate, in the overall process, a large amount of water will reflux in step 2 as in step 1, resulting in high overall energy consumption.

[0009] How to further reduce energy consumption is a common pursuit among those skilled in the art. Summary of the invention

[0010] The technical problem to be solved by the present invention is to provide a method for synthesizing ethyl acetate, which solves the problems existing in the prior art.

[0011] One of the purposes of the present invention is to solve the problem of reducing reaction energy consumption;

[0012] The second object of the present invention is to improve product quality and yield.

[0013] The invention discloses a method for synthesizing ethyl acetate, comprising the following steps:

[0014] S1. Synthesis

[0015] S11, utilizing acetic acid and ethanol to react in a countercurrent contact in a synthesis tower;

[0016] S12, generating a crude product ethyl acetate at the top of the synthesis tower;

[0017] S13, generating a synthesis tower bottom liquid at the bottom of the synthesis tower, and introducing the synthesis tower bottom liquid into a water separation tower;

[0018] S2. Extraction

[0019] S21, introducing the crude product ethyl acetate at the top of the synthesis tower in step 1 into a first extraction tank and mixing it with water for extraction to form a first water phase and a first ester phase;

[0020] S22, the first ester phase is partially introduced into the first ester distillation tower for refining, and the remaining part is refluxed to the top of the synthesis tower in step S1;

[0021] S23, the first water phase is introduced into a water separation tower;

[0022] S3, Refining

[0023] S31, the first ester phase is separated in a first ester distillation tower;

[0024] S32, obtaining industrial-grade ethyl acetate at the bottom of the first ester distillation tower, partially refluxing to the first ester distillation tower, and the rest being collected as a product;

[0025] S33, generating a distillation tower top liquid at the top of the first ester distillation tower, and returning it to the tower equipment in step 1;

[0026] S4. Water Divide

[0027] S41, introducing the synthesis tower bottom liquid generated in S13 and the first water phase generated in S23 into a water separation tower;

[0028] S42, the material produced at the top of the water diversion tower is partially refluxed to the water diversion tower after being cooled, and the rest is returned to the synthesis tower;

[0029] S43. Wastewater is generated at the bottom of the water diversion tower.

[0030] Furthermore, the first ester phase introduced into the distillation tower is first heat exchanged with the industrial-grade ethyl acetate refluxed into the first ester distillation tower, and then enters the distillation tower.

[0031] Furthermore, in the step S11, the temperature at the bottom of the synthesis tower is 90-105°C, and the temperature at the top of the tower is 65-80°C.

[0032] Furthermore, in the step S22, the bottom temperature of the first ester distillation tower is 120-135°C, and the top temperature is 105-118°C.

[0033] Furthermore, in the step S41, the temperature at the bottom of the water separation tower is 95-105°C, and the temperature at the top of the tower is 65-80°C.

[0034] Furthermore, the top reflux ratio of the synthesis tower is 1.5-3:1, the top reflux ratio of the first ester distillation tower is 6-10:1, and the top reflux ratio of the water separation tower is 1-3.5:1.

[0035] Furthermore, the method further comprises the following steps:

[0036] S5, secondary refining

[0037] S51, introducing the industrial-grade ethyl acetate product obtained in step S32 into a secondary refining tower for distillation, and obtaining electronic-grade ethyl acetate in the middle of the tower;

[0038] Furthermore, the step S33 further includes the following steps:

[0039] S331, the distillation tower top liquid generated in step S33 is first extracted with water in a second extraction tank to generate a second water phase and a second ester phase;

[0040] S332, the second aqueous phase is introduced into a water separation tower;

[0041] S333, part of the second ester phase is refluxed to the top of the distillation tower, and the rest is refluxed to the synthesis tower in step S1.

[0042] The invention also discloses an ethyl acetate synthesis device, which is connected by conventional tower equipment, pumps, heat exchangers and extraction tanks according to the path of the method.

[0043] The beneficial effects of the present invention are:

[0044] 1. An extraction step is added to effectively separate water, reduce the water content of reflux materials in the synthesis tower and refining tower, and reduce energy consumption;

[0045] 2. The extracted water phase enters the water separation tower to further recover raw materials and products to improve the yield. DETAILED DESCRIPTION

[0046] The specific implementation modes of the present invention are further described below in conjunction with examples. The following examples are only used to more clearly illustrate the technical embodiments of the present invention and are not intended to limit the protection scope of the present invention.

[0047] Example 1

[0048] The invention discloses a method for synthesizing ethyl acetate, comprising the following steps:

[0049] S1. Synthesis

[0050] S11, using acetic acid and ethanol to react in countercurrent contact in a synthesis tower; the temperature at the bottom of the synthesis tower is 90-105° C., and the top of the tower is 65-80° C.; the reflux ratio at the top of the synthesis tower is 1.5-3:1;

[0051] S12, generating a crude product ethyl acetate at the top of the synthesis tower;

[0052] S13, generating a synthesis tower bottom liquid at the bottom of the synthesis tower, and introducing the synthesis tower bottom liquid into a water separation tower;

[0053] S2. Extraction

[0054] S21, introducing the crude product ethyl acetate at the top of the synthesis tower in step 1 into a first extraction tank and mixing it with water for extraction to form a first water phase and a first ester phase;

[0055] S22, the first ester phase is partially introduced into the first ester distillation tower for refining, and the rest is refluxed to the top of the synthesis tower in step S1; the bottom temperature of the first ester distillation tower is 120-135°C, and the top temperature is 105-118°C; the top reflux ratio of the first ester distillation tower is 6-10:1;

[0056] S23, the first water phase is introduced into a water separation tower;

[0057] S3, Refining

[0058] S31, the first ester phase is separated in a first ester distillation tower;

[0059] S32, obtaining industrial-grade ethyl acetate at the bottom of the first ester distillation tower, partially refluxing to the first ester distillation tower, and the rest being collected as a product;

[0060] S33, generating a distillation tower top liquid at the top of the first ester distillation tower, and returning it to the tower equipment in step 1; step S33 comprises the following steps:

[0061] S331, the distillation tower top liquid generated in step S33 is first extracted with water in a second extraction tank to generate a second water phase and a second ester phase;

[0062] S332, the second aqueous phase is introduced into a water separation tower;

[0063] S333, the second ester phase is partially refluxed to the top of the distillation tower, and the rest is refluxed to the synthesis tower in step S1

[0064] S4. Water Divide

[0065] S41, introducing the bottom liquid of the synthesis tower generated in S13 and the first water phase generated in S23 into a water separation tower; the bottom temperature of the water separation tower is 95-105°C, and the top temperature is 65-80°C; the reflux ratio of the top of the water separation tower is 1-3.5:1;

[0066] S42, the material produced at the top of the water diversion tower is partially refluxed to the water diversion tower after being cooled, and the rest is returned to the synthesis tower;

[0067] S43. Wastewater is generated at the bottom of the water diversion tower.

[0068] Furthermore, for industrial-grade ethyl acetate, it can also be refined according to the following steps:

[0069] S5, secondary refining

[0070] S51, introducing the industrial-grade ethyl acetate product obtained in step S32 into a secondary refining tower for distillation, and obtaining electronic-grade ethyl acetate in the middle of the tower.

[0071] For this embodiment, the energy consumption of each part is as shown in Table 1:

[0072] Table 1 Energy consumption of each part

[0073]

[0074] Under this process, the purity of ethyl acetate can reach over 99.99%

[0075] In order to further illustrate the beneficial effects of the present invention, the following comparative examples are set up:

[0076] Comparative Examples 1-2

[0077] Chinese patent application number 201511026285.7 discloses a production process of ethyl acetate, in which Examples 2 to 3 are used as Comparative Examples 1 to 2 (paragraphs

[0042] to

[0045] ). The results are as follows:

[0078] Comparative Example 1: Ethyl acetate purity 99.97%, steam consumption 1.4-1.8t / t;

[0079] Comparative Example 2: Ethyl acetate purity 99.99%, steam consumption 1.1-1.2 t / t.

[0080] It can be seen that the present invention adds an extraction step at the top reflux of the synthesis tower, which greatly reduces the distillation amount and reflux amount of water, greatly reduces energy consumption, and the energy saving rate reaches 20-51%.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing ethyl acetate, characterized in that: The steps include: S1. Synthesis S11, utilizing acetic acid and ethanol to react in a countercurrent contact in a synthesis tower; S12, generating a crude product ethyl acetate at the top of the synthesis tower; S13, generating a synthesis tower bottom liquid at the bottom of the synthesis tower, and introducing the synthesis tower bottom liquid into a water separation tower; S2. Extraction S21, introducing the crude product ethyl acetate at the top of the synthesis tower in step 1 into a first extraction tank and mixing it with water for extraction to form a first water phase and a first ester phase; S22, the first ester phase is partially introduced into the first ester distillation tower for refining, and the remaining part is refluxed to the top of the synthesis tower in step S1; S23, the first water phase is introduced into a water separation tower; S3, Refining S31, the first ester phase is separated in a first ester distillation tower; S32, obtaining industrial-grade ethyl acetate at the bottom of the first ester distillation tower, partially refluxing to the first ester distillation tower, and the rest being collected as a product; S33, generating a distillation tower top liquid at the top of the first ester distillation tower, and returning it to the tower equipment in step 1; S4. Water Divide S41, introducing the synthesis tower bottom liquid generated in S13 and the first water phase generated in S23 into a water separation tower; S42, the material produced at the top of the water diversion tower is partially refluxed to the water diversion tower after being cooled, and the rest is returned to the synthesis tower; S43. Wastewater is generated at the bottom of the water diversion tower.

2. The method for synthesizing ethyl acetate according to claim 1, wherein The first ester phase introduced into the distillation tower is first heat exchanged with the industrial-grade ethyl acetate refluxed into the first ester distillation tower, and then enters the distillation tower.

3. The method for synthesizing ethyl acetate according to claim 1, wherein In the step S11, the temperature at the bottom of the synthesis tower is 90-105°C, and the temperature at the top of the tower is 65-80°C; In the step S22, the bottom temperature of the first ester distillation tower is 120-135°C, and the top temperature is 105-118°C; In the step S41, the temperature at the bottom of the water separation tower is 95-105°C, and the temperature at the top of the tower is 65-80°C.

4. The method for synthesizing ethyl acetate according to claim 1, wherein The top reflux ratio of the synthesis tower is 1.5-3:1, the top reflux ratio of the first ester distillation tower is 6-10:1, and the top reflux ratio of the water separation tower is 1-3.5:

1.

5. The method for synthesizing ethyl acetate according to claim 1, wherein The following steps are also included: S5, secondary refining S51, introducing the industrial-grade ethyl acetate product obtained in step S32 into a secondary refining tower for distillation, and obtaining electronic-grade ethyl acetate in the middle of the tower.

6. The method for synthesizing ethyl acetate according to any one of claims 1 to 5, characterized in that: The step S33 also includes the following steps: S331, the distillation tower top liquid generated in step S33 is first extracted with water in a second extraction tank to generate a second water phase and a second ester phase; S332, the second aqueous phase is introduced into a water separation tower; S333, part of the second ester phase is refluxed to the top of the distillation tower, and the rest is refluxed to the synthesis tower in step S1.

7. An ethyl acetate synthesis device, characterized in that: According to the path of the method, conventional tower equipment, pumps, heat exchangers, and extraction tanks are used for connection.

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