Purification device for recovering high-purity ethanol from waste liquid

Abstract

The purification device comprises a light component removal tower, a heavy component removal tower and a membrane dehydration assembly, an outlet of a tower kettle of the light component removal tower is connected to an inlet of the membrane dehydration assembly, an inlet of the heavy component removal tower is connected to an interception side of the membrane dehydration assembly, the light component removal tower is a pressurized rectification tower, and the heavy component removal tower is a membrane dehydration assembly. The de-heavy tower is a normal-pressure rectifying tower, and the membrane dehydration assembly is used for liquid-phase dehydration. The device disclosed by the utility model has the beneficial effects that high-purity ethanol is recovered through rectification and membrane dehydration without introducing a third-party component, and the device has the characteristics of simple process, high separation efficiency, good safety, equipment stability and the like.

Description

Technical Field

[0001] This utility model belongs to the field of ethanol recovery and purification, specifically relating to a purification device for recovering high-purity ethanol from waste liquid. Background Technology

[0002] Ethanol, commonly known as alcohol, is a basic chemical mother liquor and organic solvent. It can be used to manufacture acetic acid, beverages, flavorings, fuels, and is widely used in chemical, medical, food, and agricultural production.

[0003] Currently, food-grade alcohol is used in the production of hemodialysis materials. However, the synthesis of this material generates approximately 50 ppm of acetal and 1,3-dichlorobutane. Since acetal, 1,3-dichlorobutane, ethanol, and water all exhibit azeotropic reactions, it is difficult to reduce acetal and 1,3-dichlorobutane to below 1 ppm through distillation alone, thus failing to obtain ethanol suitable for recovery.

[0004] Therefore, it is necessary to design a separation and recovery device that can recover ethanol with low energy consumption, high efficiency and high quality without introducing third-party substances, while ensuring the removal of trace amounts of acetal and 1,3-dichlorobutane. Utility Model Content

[0005] The purpose of this invention is to provide a purification device for recovering high-purity ethanol from waste liquid.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A purification device for recovering high-purity ethanol from waste liquid includes a light-light distillation column, a heavy-light distillation column, and a membrane dehydration component. The outlet of the light-light distillation column is connected to the inlet of the membrane dehydration component, and the inlet of the heavy-light distillation column is connected to the filtration side of the membrane dehydration component. The light-light distillation column is a pressurized distillation column, the heavy-light distillation column is an atmospheric distillation column, and the membrane dehydration component is a liquid-phase dehydration device.

[0008] Preferably, the light-light-removal tower has 40 theoretical plates, and the mother liquor enters from the 32nd theoretical plate from bottom to top of the light-light-removal tower.

[0009] Preferably, the number of theoretical trays in the deweight removal tower is 80, and the inlet of the deweight removal tower is located at the 32nd theoretical tray from bottom to top in the deweight removal tower.

[0010] Preferably, the membrane material in the membrane dehydration assembly is selected from one or more of Na molecular sieve membranes, organic polymer membranes, hollow fiber membranes, and composite membranes.

[0011] Preferably, the outlet at the top of the light-light-removal tower is also connected to a pre-distillation tank.

[0012] The beneficial effects of this invention are: without introducing third-party components, by distillation and membrane dehydration, acetal and 1,3-dichlorobutane in the waste liquid are reduced to below 1 ppm, and high-purity ethanol is recovered, reducing energy consumption. In addition, the device has the characteristics of simple process, high separation efficiency, good safety and equipment stability. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] The components include: 1. Light weight removal tower; 2. Forward distillation tank; 3. Membrane dehydration unit; 4. Heavy weight removal tower. Detailed Implementation

[0015] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0016] like Figure 1 As shown, this utility model discloses a purification device for recovering high-purity ethanol from waste liquid, comprising a light-weight removal tower 1, a heavy-weight removal tower 4, and a membrane dehydration component 3. The outlet of the bottom of the light-weight removal tower 1 is connected to the inlet of the membrane dehydration component 3, and the inlet of the heavy-weight removal tower 4 is connected to the sludge-side outlet of the membrane dehydration component 3. The light-weight removal tower 1 is a plate tower or a packed tower, employing pressurized distillation; the heavy-weight removal tower 4 is a plate tower or a packed tower, employing atmospheric distillation. Liquid-phase dehydration is performed in the membrane dehydration component 3. The mother liquor enters the light-weight removal tower 1, where pressurized distillation removes an azeotrope of acetal, ethanol, and water from the top, thus removing most of the acetal. The remaining solution in the bottom of the tower is transferred to the membrane dehydration component 3 for liquid-phase dehydration. The dehydrated solution is then transferred to the heavy-weight removal tower 4, where atmospheric distillation removes a high-concentration ethanol product from the top, and ethanol waste liquid containing 1,3-dichlorobutane is discharged from the bottom.

[0017] The theoretical plate number of light component removal tower 1 is 40, and the mother liquor enters from the 32nd theoretical plate from bottom to top of light component removal tower 1.

[0018] The theoretical number of trays in the deweight removal tower 4 is 80, and the inlet of the deweight removal tower 4 is located at the 32nd theoretical tray from bottom to top in the deweight removal tower 4.

[0019] The membrane dehydration unit 3 uses a preferred permeable membrane, which is made of one or more of the following materials: Na molecular sieve membrane, organic polymer membrane, hollow fiber membrane, and composite membrane. The membrane dehydration unit 3 consists of at least one set, or two or more sets, arranged in series, parallel, or a combination of both. The outlet at the top of the light component removal tower 1 is also connected to a pre-distillation tank 2.

[0020] Process flow: Step 1: The mother liquor is sent to the light liquor removal tower 1. First, it is subjected to pressure distillation to collect the azeotrope of acetal, ethanol and water from the top of the tower and collect it in the fore-distillate tank 2. At this time, the acetal content in the bottom of the tower is ≤1ppm.

[0021] Step 2: Transfer the bottom liquid of the tower to membrane dehydration unit 3, and dehydrate it in liquid phase to below 0.05 wt.%;

[0022] Step 3: After dehydration, the ethanol enters the de-heavy distillation tower 4. Through atmospheric distillation, high-purity ethanol product is collected from the top of the tower, and ethanol waste liquid containing 1,3-dichlorobutane is discharged from the bottom of the tower.

[0023] In step one, the mother liquor comprises the following components: 75-85 wt.% ethanol, 1-50 ppm acetal, 1-50 ppm 1,3-dichlorobutane, and 10-25 wt.% water.

[0024] In step one, the feed inlet of the light-weight removal tower 1 is located on the 32nd tray from the bottom, the operating pressure is 0.01-0.2 MPa (gauge pressure), the top temperature and the outlet temperature are 60-95℃, the reflux ratio is 5-30, and the bottom temperature is 80-105℃.

[0025] In step one, the composition of the fore-distillate collected from the top of the column is: acetal content ≥0.1 wt.%, ethanol 80-95 wt.%, and water 5-20 wt.%; the composition of the ethanol-water mixture collected from the bottom of the column is: 1,3-dichlorobutane 1-60 ppm, ethanol 70-90 wt.%, and water 10-30 wt.%.

[0026] In step two, the membrane dehydration unit 3 dehydrates at a temperature of 90-110℃ and a pressure of 0.01-0.1mPa (gauge pressure), and the permeate vacuum pressure is 0.1-500pa (absolute pressure).

[0027] In step two, the membrane dehydration component 3 is a liquid phase dehydration, and the membrane material used is selected from one or more of Na molecular sieve membranes, organic polymer membranes, hollow fiber membranes, and composite membranes.

[0028] In step two, the ethanol content of the membrane dehydration unit 3 is ≥99.99%, the water content is ≤0.01%, and the 1,3-dichlorobutane content is 1-60 ppm. The permeate contains ≤1% ethanol and ≥99% water.

[0029] In step three, the theoretical number of trays in the deweight removal tower 4 is 80, and it can be a plate tower or a packed tower.

[0030] In step three, the feed inlet of the deweight removal tower 4 is located on the 32nd tray from the bottom, the operating pressure is 0.01-0.2 MPa (gauge pressure), the top temperature and the outlet temperature are 60-95℃, the reflux ratio is 5-30, and the bottom temperature is 90-110℃.

[0031] In step three, the composition of the qualified finished product taken from the top of the tower is: ethanol ≥ 99.99 wt.%, acetal 0-1 ppm, 1,3-dichlorobutane 0-1 ppm, and moisture ≤ 0.01 wt.%; the composition of the waste liquid discharged from the bottom of the tower is: 1,3-dichlorobutane content ≥ 0.1%, ethanol ≤ 99.9 wt.%, and moisture ≤ 0.01 wt.%.

[0032] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0033] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A purification apparatus for recovering high-purity ethanol from waste liquid, characterized in that: The light-removing column (1), the heavy-removing column (4) and the membrane dehydration assembly (3) are connected, the outlet of the column still of the light-removing column (1) is connected to the inlet of the membrane dehydration assembly (3), the inlet of the heavy-removing column (4) is connected to the cut-off side of the membrane dehydration assembly (3), the light-removing column (1) is a pressurized rectifying column, the heavy-removing column (4) is an atmospheric rectifying column, and the membrane dehydration assembly (3) is a liquid-phase dehydration.

2. The purification apparatus for recovering high-purity ethanol from waste liquid according to claim 1, characterized by: The number of theoretical plates of the light-removing column (1) is 40, and the mother liquor enters from the 32th theoretical plate from bottom to top.

3. The purification device for recovering high-purity ethanol from waste liquid according to claim 1, characterized by: The number of theoretical plates of the heavy-removing column (4) is 80, and the inlet of the heavy-removing column (4) is located at the 32th theoretical plate from bottom to top.

4. The purification apparatus for recovering high-purity ethanol from waste liquid according to claim 1, characterized by: The membrane material in the membrane dehydration assembly (3) is selected from one or more of Na molecular sieve membrane, organic polymer membrane, hollow fiber membrane and composite membrane.

5. The purification device for recovering high-purity ethanol from waste liquid according to claim 1, characterized by: The outlet at the top of the light-removing column (1) is also connected to a forefraction tank (2).

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