Device and process for recovering butyl acetate in waste liquid

Abstract

The invention relates to the technical field of waste liquid recovery, in particular to a device and a process for recovering butyl acetate in waste liquid. Comprising a waste liquid inlet (1), a first valve (2), a waste liquid distributor (3), an adsorption material (4), a steam distributor (5), a steam inlet (6), a waste liquid outlet (7), a condenser (8), a collecting tank (9), a second valve (10) and an adsorption tower (11), the adsorption material (4) is adopted, the n-butyl acetate in the wastewater is adsorbed in a normal-temperature adsorption mode, then the adsorbent is regenerated and n-butyl acetate is recovered in a mode of heating the adsorbent by steam, and as only a small amount of adsorbent needs to be heated, the method has the advantages of reducing energy consumption and being simple to operate, and the production cost can be remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of waste liquid recovery, and specifically, to a recovery device and process for butyl acetate in waste liquid. Background Art

[0002] Butyl acetate is a common volatile organic compound and is widely used as an extraction solvent in antibiotic production. In the waste liquid after extraction, because butyl acetate has a certain solubility in water, the waste water containing butyl acetate is characterized by a relatively low content of butyl acetate (the butyl acetate content is between 0.3 - 1.5 wt%), and due to characteristics such as containing solid mycelium and being prone to foaming of the material, if the waste liquid containing butyl acetate is directly sent to the wastewater treatment plant, it will cause an increase in the content of BOD (biochemical oxygen demand) and COD (chemical oxygen demand) in the waste liquid, increasing the difficulty of environmental protection wastewater treatment. Therefore, the recovery of butyl acetate in wastewater is a common problem in the antibiotic production process, and the recovery rate and recovery energy consumption of butyl acetate directly determine the cost of the product. At present, the recovery methods for wastewater containing trace amounts of butyl acetate in factories mostly adopt distillation, azeotropic distillation, steam stripping, etc., which require heating a large amount of wastewater to the boiling point, consuming a large amount of heat sources.

[0003] Chinese Utility Model Patent CN219585855U discloses a butyl acetate recovery device, including a butyl acetate tank. The butyl acetate tank is connected to a rectification column through a first heat exchanger. The bottom of the rectification column is connected to the first heat exchanger through a pipeline to exchange heat with butyl acetate and discharge. A preheater is also arranged between the first heat exchanger and the rectification column. The top of the rectification column is connected to a second heat exchanger. The second heat exchanger is connected to a phase separator through a condenser. The butyl acetate tank is also connected to the preheater through the second heat exchanger and then connected to the rectification column. The phase separator is connected to a recovery tank. This utility model uses the high-temperature gas and high-temperature liquid at the top and bottom of the rectification column to preheat the butyl acetate wastewater, reducing the energy consumption of the preheater, thereby improving energy efficiency. At the same time, when the high-temperature gas at the top of the rectification column exchanges heat with the butyl acetate wastewater, it can also be cooled and lowered in temperature first, and energy can also be saved and efficiency can be improved when passing through the condenser. However, the recovery process involves heating a large amount of wastewater, and it is not suitable for the recovery of wastewater with a low butyl acetate content either. Summary of the Invention

[0004] The first aspect of the present invention provides a recovery device for butyl acetate in waste liquid, comprising: a waste liquid inlet, a first valve, a waste liquid distributor, an adsorption material, a steam distributor, a steam inlet, a waste liquid outlet, a condenser, a collection tank, a second valve, and an adsorption tower; the waste liquid distributor, the adsorption material, and the steam distributor are arranged in the adsorption tower, the adsorption material is located in the middle of the adsorption tower, and the waste liquid distributor and the steam distributor are respectively located at the bottom end and the top end of the adsorption tower; the waste liquid inlet is communicated with the waste liquid distributor through a pipeline via the first valve; the steam inlet is communicated with the steam distributor through a pipeline; the waste liquid outlet is communicated with the top end of the adsorption tower through a pipeline; the top of the condenser is communicated with the bottom end of the adsorption tower through a pipeline via the second valve, and the bottom of the condenser is communicated with the collection tank through a pipeline.

[0005] The adsorption material includes columnar activated carbon.

[0006] The aspect ratio of the columnar activated carbon is 2 - 4.

[0007] Optionally, the aspect ratio of the columnar activated carbon is 2 - 3.

[0008] The diameter of the columnar activated carbon is 1.5 - 6 mm.

[0009] Optionally, the diameter of the columnar activated carbon is 3 - 6 mm.

[0010] The present invention has found through research that when the aspect ratio of the columnar activated carbon is 2 - 4 and the diameter is 1.5 - 6 mm, the content of butyl acetate in the treated waste liquid can be no higher than 0.2 wt%. It may be that the columnar particles with an aspect ratio of 2 - 4 can form uniform pore channels during stacking, reducing the fluid short - circuit phenomenon and prolonging the contact time between the waste liquid and the activated carbon. The particles with a diameter of 1.5 - 6 mm can not only maintain a high specific surface area (enhancing the adsorption capacity) but also avoid the problems of excessive bed - layer pressure drop or blockage caused by overly fine particles. At the same time, the specific diameter shortens the diffusion path of butyl acetate molecules into the micropores, and the aspect ratio of 2 - 4 ensures the stability of the particle structure and avoids the decrease in the utilization rate of internal pores due to excessive length.

[0011] Working principle: The waste liquid containing butyl acetate enters the adsorption tower equipped with the adsorption material evenly through the waste liquid distributor. The butyl acetate is adsorbed by the adsorption material, and the concentration of butyl acetate in the waste liquid decreases. When the adsorption material is close to saturation, the waste liquid is discharged from the adsorption tower, and steam enters from the top through the steam distributor to heat the adsorption material. The butyl acetate is vaporized on the adsorption material, and the mixture of vaporized butyl acetate and water vapor is discharged from the bottom of the adsorption tower, condensed and recovered by the condenser, and the adsorption material is regenerated and enters the next adsorption cycle for recycling.

[0012] The second aspect of the present invention provides a process for recovering butyl acetate from waste liquid, comprising the following steps:

[0013] S1. Keep the first valve in the connected state and the second valve in the closed state. Pass the initial waste liquid through the waste liquid inlet, the first valve, and the waste liquid distributor into the adsorption tower in sequence, and then discharge it from the waste liquid outlet after passing through the adsorption material to obtain the treated waste liquid.

[0014] S2. Keep the first valve in the closed state and the second valve in the connected state. Pass the steam through the steam inlet and the steam distributor into the adsorption tower in sequence. After eluting the adsorption material, obtain the mixed steam. The mixed steam is condensed in the condenser and then enters the collection tank to obtain the aqueous solution of butyl acetate.

[0015] The content of butyl acetate in the initial waste liquid is 0.3 - 1.5 wt%.

[0016] Optionally, the content of butyl acetate in the initial waste liquid is 0.3 - 1 wt%.

[0017] The temperature of the initial waste liquid is 10 - 35 °C.

[0018] Optionally, the temperature of the initial waste liquid is 10 - 30 °C.

[0019] The speed of the initial waste liquid entering the adsorption tower is 10 - 20 L / h.

[0020] Optionally, the speed of the initial waste liquid entering the adsorption tower is 12 - 18 L / h.

[0021] Beneficial Effects

[0022] 1. The device of the present invention is provided with an adsorption material in the adsorption tower, and adsorbs butyl acetate in the wastewater by adsorption, which has the advantages of reducing energy consumption and simple operation.

[0023] 2. The adsorption material is selected as columnar activated carbon, which can improve the waste liquid recovery efficiency, and the speed of the initial waste liquid entering the adsorption tower can reach 10 - 20 L / h.

[0024] 3. Limiting the aspect ratio of the columnar activated carbon to be 2 - 4 and the diameter to be 1.5 - 6 mm can make the content of butyl acetate in the treated waste liquid not higher than 0.2 wt%.

[0025] 4. In the process of recovering butyl acetate in the antibiotic extraction solvent of the present invention, by controlling the temperature of the initial waste liquid to be 10 - 35 °C, it can be carried out at room temperature. While reducing energy consumption, the content of butyl acetate in the treated waste liquid is not higher than 0.05 wt%.

[0026] 5. The present invention can regenerate the adsorption material by heating the adsorbent with steam, and can be recycled, further reducing the production cost. Description of the Drawings

[0027] Figure 1 Schematic diagram of the recovery device for butyl acetate in the waste liquid in Example 1.

[0028] Among them, 1. Waste liquid inlet; 2. First valve; 3. Waste liquid distributor; 4. Adsorbent material; 5. Steam distributor; 6. Steam inlet; 7. Waste liquid outlet; 8. Condenser; 9. Collection tank; 10. Second valve; 11. Adsorption tower. Detailed implementation mode

[0029] Example 1

[0030] A recovery device for butyl acetate in waste liquid, as Figure 1 shown, includes: waste liquid inlet 1, first valve 2, waste liquid distributor 3, adsorbent material 4, steam distributor 5, steam inlet 6, waste liquid outlet 7, condenser 8, collection tank 9, second valve 10 and adsorption tower 11; a waste liquid distributor 3, an adsorbent material 4 and a steam distributor 5 are arranged in the adsorption tower 11, the adsorbent material 4 is located in the middle of the adsorption tower 11, and the waste liquid distributor 3 and the steam distributor 5 are respectively located at the bottom end and the top end of the adsorption tower 11; the waste liquid inlet 1 is communicated with the waste liquid distributor 3 through a pipeline via the first valve 2; the steam inlet 6 is communicated with the steam distributor 5 through a pipeline; the waste liquid outlet 7 is communicated with the top end of the adsorption tower 11 through a pipeline; the top of the condenser 8 is communicated with the bottom end of the adsorption tower 11 through a pipeline via the second valve 10, and the bottom of the condenser 8 is communicated with the collection tank 9 through a pipeline; the adsorbent material 4 is columnar wood activated carbon with a length-to-diameter ratio of 3, and the diameter of the columnar wood activated carbon is 5 mm; the diameter of the adsorption tower 11 is 150 mm and the height is 600 mm.

[0031] Working principle: The waste liquid containing butyl acetate enters the adsorption tower 11 equipped with the adsorbent material 4 evenly through the waste liquid distributor 3, the butyl acetate is adsorbed by the adsorbent material 4, and the concentration of butyl acetate in the waste liquid decreases; when the adsorbent material 4 is close to saturation in adsorption, the waste liquid is discharged from the adsorption tower 11, steam is introduced from the top through the steam distributor 5 to heat the adsorbent material 4, the butyl acetate is vaporized on the adsorbent material 4, and the mixture of vaporized butyl acetate and water vapor is discharged from the bottom of the adsorption tower 11, condensed and recovered by the condenser 8, the regeneration of the adsorbent material 4 is completed, and it enters the next adsorption cycle for recycling.

[0032] A process for recovering butyl acetate from waste liquid is the following steps:

[0033] S1, keep the first valve 2 in a connected state and the second valve 10 in a closed state, pass the initial waste liquid through the waste liquid inlet 1, the first valve 2 and the waste liquid distributor 3 into the adsorption tower 11 in sequence, and then discharge it from the waste liquid outlet 7 after passing through the adsorbent material 4 to obtain the treated waste liquid;

[0034] S2. Keep the first valve 2 closed and the second valve 10 in a connected state. Pass steam through the steam inlet 6 and the steam distributor 5 into the adsorption tower 11 in sequence. After eluting the adsorption material 4, a mixed steam is obtained. The mixed steam is condensed in the condenser 8 and then enters the collection tank 9 to obtain an aqueous solution of butyl acetate.

[0035] The initial waste liquid is penicillin extraction waste liquid (the solvent is water), and the content of butyl acetate is 0.7 wt%. The temperature of the initial waste liquid is 25°C. The speed of the initial waste liquid entering the adsorption tower 11 is 16 L / h, and it is continuously introduced for 4 h.

[0036] Comparative Example 1

[0037] The specific implementation method is the same as that in Example 1; the difference is that the temperature of the initial waste liquid in Comparative Example 1 is 40°C.

[0038] Comparative Example 2

[0039] The specific implementation method is the same as that in Example 1; the difference is that the adsorption material 4 in Comparative Example 2 is columnar wood activated carbon with an aspect ratio of 3, and the diameter of the columnar wood activated carbon is 8 mm.

[0040] Performance test method

[0041] 1. Detect the content of butyl acetate in the treated waste liquid discharged first (0 h) in the examples and comparative examples.

[0042] 2. Detect the content of butyl acetate in the treated waste liquid discharged at 4 h in the examples and comparative examples.

[0043] The test data are listed in Table 1.

[0044] Performance test data

[0045] Table 1

[0046] Content of butyl acetate in waste liquid (0 h) Content of butyl acetate in waste liquid (4 h) Example 1 0.01 wt% 0.04 wt% Comparative Example 1 0.1 wt% 0.3 wt% Comparative Example 2 0.1 wt% 0.4 wt% 。

Claims

1. A recovery device for butyl acetate in waste liquid, characterized in that, Comprising: Waste liquid inlet (1), first valve (2), waste liquid distributor (3), adsorption material (4), steam distributor (5), steam inlet (6), waste liquid outlet (7), condenser (8), collection tank (9), second valve (10) and adsorption tower (11); A waste liquid distributor (3), an adsorption material (4) and a steam distributor (5) are arranged in the adsorption tower (11), the adsorption material (4) is located in the middle of the adsorption tower (11), and the waste liquid distributor (3) and the steam distributor (5) are respectively located at the bottom end and the top end of the adsorption tower (11); The waste liquid inlet (1) is communicated with the waste liquid distributor (3) through a pipeline via the first valve (2); The steam inlet (6) is communicated with the steam distributor (5) through a pipeline; The waste liquid outlet (7) is communicated with the top end of the adsorption tower (11) through a pipeline; The top of the condenser (8) is communicated with the bottom end of the adsorption tower (11) through a pipeline via the second valve (10), and the bottom of the condenser (8) is communicated with the collection tank (9) through a pipeline.

2. The recovery device for butyl acetate in waste liquid according to claim 1, wherein, The adsorption material (4) comprises columnar activated carbon.

3. The recovery device for butyl acetate in waste liquid according to claim 2, wherein The aspect ratio of the columnar activated carbon is 2 - 4.

4. The recovery device for butyl acetate in waste liquid according to claim 3, characterized in that, The diameter of the columnar activated carbon is 1.5 - 6 mm.

5. A process for recovering butyl acetate from waste liquid by the device according to any one of claims 1-4, characterized in that, Comprising the following steps: S1, keep the first valve (2) in a connected state and the second valve (10) in a closed state, pass the initial waste liquid through the waste liquid inlet (1), the first valve (2) and the waste liquid distributor (3) into the adsorption tower (11) in sequence, and then discharge it from the waste liquid outlet (7) after passing through the adsorption material (4) to obtain the treated waste liquid; S2, keep the first valve (2) in a closed state and the second valve (10) in a connected state, pass the steam through the steam inlet (6) and the steam distributor (5) into the adsorption tower (11) in sequence, elute the adsorption material (4), and obtain a mixed steam. The mixed steam is condensed in the condenser (8) and then enters the collection tank (9) to obtain an aqueous solution of butyl acetate.

6. The process for recovering butyl acetate from waste liquid by the device according to claim 5, characterized in that, The content of butyl acetate in the initial waste liquid is 0.3 - 1.5 wt%.

7. The process for recovering butyl acetate from waste liquid by the device according to claim 5, characterized in that, The temperature of the initial waste liquid is 10 - 35 °C.

8. The process for recovering butyl acetate from waste liquid by the device according to claim 7, characterized in that, The temperature of the initial waste liquid is 10 - 30 °C.

9. The process for recovering butyl acetate in waste liquid by the device according to claim 8, characterized in that, The speed at which the initial waste liquid enters the adsorption tower (11) is 10 - 20 L / h.

10. The process for recovering butyl acetate in waste liquid by the device according to claim 9, characterized in that, The speed at which the initial waste liquid enters the adsorption tower (11) is 12 - 18 L / h.

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