Efficient recovery device suitable for ethylene glycol raffinate in transesterification method

Abstract

The utility model discloses an efficient recovery device suitable for ethylene glycol residual liquid in a transesterification method. The efficient recovery device comprises a residual liquid buffer tank (1), a residual liquid pump (2), an evaporator (3), an ethylene glycol refining tower (4), a vacuum pump set (5), a buffer tank (6), an evaporative condenser (7) and a tower top condenser (8). The residual liquid buffer tank (1) is connected with an inlet of the residual liquid pump (2), an outlet of the residual liquid pump (2) is connected with an inlet of the evaporator (3), a bottom outlet of the evaporator (3) is connected with the buffer tank (6), the top of the evaporator (3) is connected with the evaporative condenser (7), an outlet of the evaporative condenser (7) is connected with the buffer tank (6), the buffer tank (6) is connected with the ethylene glycol refining tower (4), and the ethylene glycol refining tower (4) is connected with the overhead condenser (8). And the evaporative condenser (7) and the overhead condenser (8) are respectively connected with the vacuum pump set (5). The process is simple, operation is convenient, the problem of material waste in the prior art is solved, the product yield is increased, and economic benefits are created.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical production, in particular to an ethylene glycol recovery device, and more particularly to a residual liquid recovery device for co-producing ethylene glycol by an ester exchange method. Background Art

[0002] Ethylene glycol is primarily used in the production of polyester, terylene, polyester resins, desiccant, plasticizer, surfactant, synthetic fibers, cosmetics, and explosives. It is also used as a solvent for dyes and inks, as an antifreeze agent for engines, as a gas dehydrator, in the manufacture of resins, and as a wetting agent for cellophane, fibers, leather, and adhesives. Currently, the transesterification process for the co-production of ethylene glycol directly discharges waste liquid containing ethylene glycol. Based on a 50,000 tons / year ethylene glycol production scale, approximately 1% to 5% of the residual liquid is discharged annually. This residual liquid is rich in ethylene glycol, sodium carbonate, and ethylene carbonate. Some companies currently sell this residual liquid as a low-cost waste liquid, while others incinerate it. This problem accumulates over time, leading to significant losses and fierce competition within the industry. Furthermore, the waste treatment process also poses a certain degree of environmental harm. Recovering this residual liquid through recycling would significantly increase economic benefits. Therefore, the present invention proposes a highly efficient recovery device for ethylene glycol residual liquid in the transesterification process to further recover the discharged ethylene glycol residual liquid. Summary of the Invention

[0003] The purpose of the utility model is to overcome the above-mentioned shortcomings and provide an ethylene glycol residual liquid recovery device which is environmentally friendly, has a high product yield and is easy to operate.

[0004] The purpose of this utility model is achieved in this way:

[0005] The invention relates to a high-efficiency recovery device for ethylene glycol residual liquid in an ester exchange process, comprising a residual liquid buffer tank (1), a residual liquid pump (2), an evaporator (3), an ethylene glycol refining tower (4), a vacuum pump group (5), a buffer tank (6), an evaporative condenser (7), and a tower top condenser (8). The residual liquid buffer tank (1) is connected to the inlet of the residual liquid pump (2), the outlet of the residual liquid pump (2) is connected to the inlet of the evaporator (3), the bottom outlet of the evaporator (3) is connected to the buffer tank (6), the top of the evaporator (3) is connected to the evaporative condenser (7), the outlet of the evaporative condenser (7) is connected to the buffer tank (6), the buffer tank (6) is connected to the ethylene glycol refining tower (4), the ethylene glycol refining tower (4) is connected to the tower top condenser (8), and the evaporative condenser (7) and the tower top condenser (8) are respectively connected to the vacuum pump group (5).

[0006] The pressure of the evaporator (3) is 3 kPaA, and the pressure of the ethylene glycol refining tower (4) is 5 kPaA; a vacuum pump is used for vacuuming the evaporator (3) and the ethylene glycol refining tower (4); the vacuum pump group (5) is a screw pump; the evaporator (3) adopts falling film evaporation; and the buffer tank (6) discharges the material to the ethylene glycol refining tower (4) through the pressure difference.

[0007] The utility model has the following positive effects:

[0008] (1) The high-efficiency recovery device for ethylene glycol residual liquid utilizes an evaporator for evaporation separation, and then utilizes an ethylene glycol refining tower to purify the product ethylene glycol, with a high product yield, thereby increasing its economic benefits; and it adopts negative pressure operation conditions, thereby reducing cost consumption and saving energy;

[0009] (2) The high-efficiency recovery device for ethylene glycol residue adopts falling film evaporation to achieve high separation efficiency and high product yield;

[0010] (3) The high-efficiency recovery device of ethylene glycol residual liquid returns the residual liquid to the residual liquid tank for further circulation after separation at the bottom of the evaporator, thereby reducing waste liquid discharge, thereby reducing environmental pollution and improving the utilization rate of residual liquid;

[0011] (4) The high-efficiency recovery device for ethylene glycol residual liquid has a simple process and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the device of the utility model DETAILED DESCRIPTION

[0013] The present invention will be further described below in conjunction with the embodiments. The following embodiments are intended to illustrate the present invention rather than to limit the present invention.

[0014] The ethylene glycol residue produced by the transesterification process is transported to the evaporator (3) for separation via the residue pump (2). The bottom is connected to the residue tank (1) for further circulation. After separation, the top material enters the evaporation condenser (7) for condensation. The gas phase is discharged through the vacuum pump group (5). The liquid phase is connected to the buffer tank (6) and enters the ethylene glycol refining tower (4) for further processing through the pressure difference. The ethylene glycol product is extracted from the top of the tower, and the bottom material is discharged intermittently. The pressure of the evaporator (3) is 3kpaA, and the pressure of the ethylene glycol refining tower (4) is 5kpaA. A vacuum pump is used for vacuuming the evaporator (3) and the ethylene glycol refining tower (4). The vacuum pump group (5) is a screw pump. The evaporator (3) adopts falling film evaporation. The buffer tank discharges the material to the ethylene glycol refining tower (4) through the pressure difference. Example

[0015] Example 1 operating parameters:

[0016] The pressure of the evaporator (3) is 3kpaA, and the pressure of the glycol refining tower (4) is 5kpaA

[0017] Specific methods:

[0018] First, the vacuum pump group (5) is started to evacuate the evaporator (3) and the ethylene glycol refining tower (4) to the above-mentioned pressure. After stabilization, the residual liquid in the residual liquid tank (1) is transported to the evaporator (3) through the residual liquid pump (2) at a flow rate of 15,000 kg / h, and then connected to the buffer tank (6) through falling film evaporation. Then, it is connected to the ethylene glycol refining tower (4) through a pressure difference. After distillation treatment, 99.5% ethylene glycol product is obtained at the top of the ethylene glycol refining tower (4) with a flow rate of 6,613 kg / h. The bottom of the tower is discharged intermittently as needed.

[0019] Example 2 operating parameters:

[0020] The pressure of the evaporator (3) is 5kpaA, and the pressure of the glycol refining tower (4) is 5kpaA

[0021] Specific methods:

[0022] First, the vacuum pump group (5) is started to evacuate the evaporator (3) and the ethylene glycol refining tower (4) to the above-mentioned pressure. After stabilization, the residual liquid in the residual liquid tank (1) is transported to the evaporator (3) through the residual liquid pump (2) at a flow rate of 15,000 kg / h, and then connected to the buffer tank (6) through falling film evaporation. Then, it is connected to the ethylene glycol refining tower (4) through a pressure difference. After distillation treatment, 99.2% ethylene glycol product is obtained at the top of the ethylene glycol refining tower (4) with a flow rate of 5,292 g / h. The bottom of the tower is discharged intermittently as needed.

[0023] As shown by the results of the above-mentioned specific examples 1 and 2, the amount of ethylene glycol produced in example 1 is the largest, and the recovery effect is better.

[0024] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be regarded as within the scope of protection of the present invention.

Claims

1. Applicable to the efficient recovery device of ethylene glycol residue in the transesterification process, characterized by: The invention comprises a residual liquid buffer tank (1), a residual liquid pump (2), an evaporator (3), an ethylene glycol refining tower (4), a vacuum pump group (5), a buffer tank (6), an evaporative condenser (7), and a tower top condenser (8), wherein the residual liquid buffer tank (1) is connected to the inlet of the residual liquid pump (2), the outlet of the residual liquid pump (2) is connected to the inlet of the evaporator (3), the bottom outlet of the evaporator (3) is connected to the buffer tank (6), the top of the evaporator (3) is connected to the evaporative condenser (7), the outlet of the evaporative condenser (7) is connected to the buffer tank (6), the buffer tank (6) is connected to the ethylene glycol refining tower (4), the ethylene glycol refining tower (4) is connected to the tower top condenser (8), and the evaporative condenser (7) and the tower top condenser (8) are respectively connected to the vacuum pump group (5).

2. The high-efficiency recovery device for ethylene glycol residue in the transesterification process according to claim 1, characterized in that The pressure of the evaporator (3) is 3 kpaA, and the pressure of the ethylene glycol refining tower (4) is 5 kpaA.

3. The high-efficiency recovery device for ethylene glycol residue in the transesterification process according to claim 1 is characterized in that A vacuum pump is used as a spare for the evaporator (3) and the ethylene glycol refining tower (4).

4. The high-efficiency recovery device for ethylene glycol residue in the transesterification process according to claim 1, characterized in that The vacuum pump group (5) is a screw pump.

5. The high-efficiency recovery device for ethylene glycol residue in the transesterification process according to claim 1 is characterized in that The evaporator (3) adopts falling film evaporation.

6. The high-efficiency recovery device for ethylene glycol residue in the transesterification process according to claim 1, characterized in that The buffer tank (6) is directly connected to the glycol refining tower (4) and discharges the material by pressure difference.

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