A mother liquor treatment system for the production of 4,4'-diaminodiphenyl ether
By introducing a sedimentation tank and overflow plate design into the mother liquor treatment system, combined with vacuum feeding and gravity feeding, the problems of reduced distillation column throughput and pump wear caused by particulate matter in the mother liquor were solved, achieving more efficient mother liquor treatment and longer pump life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GANSU LUYUDONGYI FINE CHEM CO LTD
- Filing Date
- 2025-08-06
- Publication Date
- 2026-07-03
Smart Images
Figure CN224442201U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical mother liquor treatment technology, specifically a mother liquor treatment system for the production of 4,4'-diaminodiphenyl ether. Background Technology
[0002] 4,4'-Diaminodiphenyl ether is an organic compound mainly used in the production of heat-resistant plastics such as polyimide resin and polymaleimide resin, and can also be used as a crosslinking agent. In the production of 4,4'-diaminodiphenyl ether, dimethylacetamide is added to a reaction vessel followed by dinitrodiphenyl ether. The mixture undergoes reaction, hydrogenation reduction, filtration, cooling, and centrifugation to obtain wet 4,4'-diaminodiphenyl ether. However, the mother liquor from centrifugation contains a large amount of solvent, therefore, it needs to be treated to recover the dimethylacetamide.
[0003] Currently, the typical method for mother liquor recovery involves pumping the primary mother liquor from the centrifuge into a tank, then using a pump to a coarse distillation kettle for coarse distillation. This coarse distillation separates some dimethylacetamide, and the remaining material enters a secondary centrifuge to further separate the crude product from the coarse distillation. The mother liquor then enters a secondary mother liquor tank, which is directly pumped to the crude DMAC solvent tank in the tank area before being fed into a distillation column for purification and reuse. However, this method still has some problems. The secondary mother liquor contains particulate matter, and when it reaches the distillation column for purification, the high solid content can significantly exceed the column's processing capacity, impacting the distillation column pump's failure rate. Furthermore, the particulate matter in the mother liquor accelerates impeller wear in the transfer pump, affecting its lifespan. Therefore, it is necessary to develop a mother liquor treatment system for 4,4'-diaminodiphenyl ether production that can reduce the particulate matter content in the mother liquor, increase the distillation column's throughput, and reduce the failure rate of the submersible pump. Utility Model Content
[0004] To address the above technical problems, this utility model provides a 4,4'-diaminodiphenyl ether production mother liquor treatment system that can reduce the particulate matter content in the mother liquor, increase the distillation column throughput, and reduce the failure rate of the transfer pump. This solves the problem that existing treatment methods cannot remove particulate matter from the mother liquor in a timely manner, resulting in a decrease in the distillation column throughput and severe wear of the transfer pump impeller.
[0005] To solve the above-mentioned technical problems, the present invention provides a mother liquor treatment system for the production of 4,4'-diaminodiphenyl ether, comprising a primary centrifuge, a crude distillation kettle, and a secondary centrifuge. The inlet of the primary centrifuge is connected to the mother liquor inlet pipe, the liquid outlet of the primary centrifuge is connected to the inlet of the primary sedimentation tank via a pipe, the outlet of the primary sedimentation tank is connected to the inlet of the crude distillation kettle via a pipe, the crude distillation kettle is connected to a vacuum pump via a pipe, the gas outlet of the crude distillation kettle is connected to a condenser via a pipe, and the liquid outlet of the crude distillation kettle is connected to a buffer tank via a pipe, the outlet of the condenser is connected to the inlet of the solvent tank, the outlet of the buffer tank is connected to the inlet of the secondary centrifuge via a pipe, the liquid outlet of the secondary centrifuge is connected to the inlet of the secondary sedimentation tank via a pipe, and the outlets of the solvent tank and the secondary sedimentation tank are both connected to a distillation feed pipe via pipes.
[0006] Furthermore, an overflow plate is fixedly connected to the middle of the primary sedimentation tank, and three overflow plates with progressively decreasing heights are fixedly connected at intervals from the inlet to the outlet inside the secondary sedimentation tank.
[0007] Furthermore, the discharge port of the primary sedimentation tank is connected to the inlet of the primary mother liquor tank via a pipe, and the discharge port of the primary mother liquor tank is connected to the inlet of the coarse steaming kettle via a pipe.
[0008] Furthermore, the outlet of the secondary sedimentation tank is connected to the inlet of the secondary mother liquor tank via a pipeline, and the outlet of the secondary mother liquor tank is connected to the distillation feed pipe via a pipeline.
[0009] Furthermore, valves are connected to the pipelines between the primary centrifuge and the primary sedimentation tank, the primary sedimentation tank and the primary mother liquor tank, the primary mother liquor tank and the crude distillation kettle, the crude distillation kettle and the vacuum pump, the crude distillation kettle and the condenser, the condenser and the solvent tank, the crude distillation kettle and the buffer tank, the buffer tank and the secondary centrifuge, the secondary centrifuge and the secondary sedimentation tank, the secondary sedimentation tank and the secondary mother liquor tank, the secondary mother liquor tank and the distillation feed pipe, and the solvent tank and the distillation feed pipe.
[0010] Furthermore, a delivery pump is connected to the pipeline between the secondary mother liquor tank and the distillation feed pipe, and between the solvent tank and the distillation feed pipe.
[0011] This utility model has the following advantages compared with the prior art:
[0012] 1. This utility model connects a primary sedimentation tank after a primary centrifuge and a secondary sedimentation tank after a secondary centrifuge. After two sedimentation processes, the solid particulate material in the mother liquor is reduced to less than 5%, allowing the distillation column to completely separate this solid material, thereby increasing the distillation column's throughput. Simultaneously, the significant reduction in solid particulate material reduces wear on the impeller of the transfer pump, thus extending the pump's service life. Furthermore, by using vacuum feeding when feeding the mother liquor from the primary mother liquor tank to the coarse distillation vessel, the use of a submersible pump is avoided, preventing pump damage from impacting production efficiency.
[0013] 2. This utility model achieves two-stage sedimentation by setting an overflow plate in the primary sedimentation tank and three overflow plates with progressively decreasing heights in the secondary sedimentation tank, thereby improving the sedimentation effect and removing most of the solid particulate matter from the mother liquor. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the connection structure of this utility model.
[0015] In the diagram: 1. Primary centrifuge, 2. Primary sedimentation tank, 3. Primary mother liquor tank, 4. Coarse distillation kettle, 5. Condenser, 6. Solvent tank, 7. Buffer tank, 8. Secondary centrifuge, 9. Secondary sedimentation tank, 10. Secondary mother liquor tank, 11. Vacuum pump. Detailed Implementation
[0016] The present invention will be further described below with reference to the accompanying drawings.
[0017] Currently, in the production process of 4,4'-diaminodiphenyl ether, to recover and reuse the added solvent dimethylacetamide from the mother liquor, the mother liquor is centrifuged once and then pumped to a coarse distillation vessel. The crude dimethylacetamide obtained from the coarse distillation is condensed and recovered to a solvent tank, and then enters a rectification vessel for purification. The mother liquor after coarse distillation is centrifuged again and then enters the rectification vessel for purification. However, the mother liquor contains a large amount of particulate matter, which is not treated during the mother liquor treatment process. As a result, when the mother liquor enters the rectification column, it exceeds the column's processing capacity, leading to a decrease in the mother liquor throughput, high operating pressure on the rectification column pumps, and increased susceptibility to damage. Furthermore, the use of pumps for transportation in each stage of the mother liquor treatment process causes severe wear on the impellers of the transfer pumps, reducing their service life. Therefore, a precipitation method is needed to remove the particulate matter from the mother liquor to solve the problems in the company's current mother liquor treatment process. Figure 1The system shown is a mother liquor treatment system for the production of 4,4'-diaminodiphenyl ether, including a primary centrifuge 1, a coarse distillation kettle 4, and a secondary centrifuge 8. The inlet of the primary centrifuge 1 is connected to a mother liquor feed pipe, and a valve is connected to the mother liquor feed pipe to control the mother liquor feed. The liquid outlet of the primary centrifuge 1 is connected to the inlet on one side of the primary sedimentation tank 2 via a pipe, and a valve is connected to the pipe. The use of a transfer pump is avoided as much as possible in the initial stage of treatment. The liquid outlet of the primary centrifuge 1 is set at a height higher than the inlet of the primary sedimentation tank 2, so the mother liquor after the first centrifugation flows by gravity into the sedimentation tank 2. The mother liquor enters the primary sedimentation tank 2. The outlet of the primary sedimentation tank 2 is connected to the inlet of the primary mother liquor tank 3 via a pipe, which is equipped with a valve. The outlet of the primary sedimentation tank 2 is positioned higher than the inlet of the primary mother liquor tank 3 to allow the mother liquor to flow from the primary sedimentation tank 2 into the primary mother liquor tank 3 by gravity. The outlet of the primary mother liquor tank 3 is connected to the inlet of the coarse distillation kettle 4 via a pipe, which is also equipped with a valve. The coarse distillation kettle 4 is connected to the vacuum pump 11 via a pipe. The coarse distillation kettle 4 is fed via vacuum feeding, avoiding the use of a transfer pump. The gas outlet of the coarse distillation kettle 4 is connected to the cooling system via a pipe. Condenser 5 is connected to the liquid outlet, which is connected to buffer tank 7 via a pipeline. Valves are connected to both pipelines. Gravity feeding can still be achieved between the liquid outlet of the coarse distillation vessel 4 and buffer tank 7 via a height difference, or a conveying pump can be used for feeding. The outlet of condenser 5 is connected to the inlet of solvent tank 6, and a valve is connected to the pipeline. The outlet of buffer tank 7 is connected to the inlet of secondary centrifuge 8 via a pipeline, and a valve is connected to the pipeline. Gravity feeding can also be achieved between the outlet of buffer tank 7 and the inlet of secondary centrifuge 8 via a height difference, or a conveying pump can be used on the pipeline. The pump is used to transport the mother liquor. The liquid outlet of the secondary centrifuge 8 is connected to the inlet of the secondary sedimentation tank 9 through a pipeline. A valve is connected to the pipeline. The liquid outlet of the secondary centrifuge 8 is set at a higher height than the inlet of the secondary sedimentation tank 9 to achieve gravity feeding. The outlet of the secondary sedimentation tank 9 is connected to the inlet of the secondary mother liquor tank 10 through a pipeline. The outlets of the solvent tank 6 and the secondary mother liquor tank 10 are both connected to the distillation feed pipe through pipelines. Valves and transfer pumps are connected to the pipelines between the secondary mother liquor tank 10 and the distillation feed pipe, and between the solvent tank 6 and the distillation feed pipe.
[0018] To ensure a good sedimentation effect and remove most of the particulate matter from the mother liquor, the primary sedimentation tank 2 and the secondary sedimentation tank 9 have conventional tank structures. An overflow plate is fixedly connected to the middle of the primary sedimentation tank 2, which enables two-stage sedimentation in a single pass. The discharge port of the primary sedimentation tank 2 is lower than the upper edge of the overflow plate. The solid content in the mother liquor after passing through the primary sedimentation tank 2 will be reduced by 35-40%. Inside the secondary sedimentation tank 9, three overflow plates of progressively decreasing height are fixedly connected at intervals from the inlet to the outlet, which enables four-stage sedimentation in a single pass. The discharge port of the secondary sedimentation tank 9 is lower than the upper edge of the overflow plate near the outlet. The solid content in the mother liquor after passing through the secondary sedimentation tank 9 can be reduced to below 5%.
[0019] It should be noted that in this embodiment, the primary centrifuge 1, secondary centrifuge 8, crude distillation kettle 4, condenser 5, solvent tank 6, buffer tank 7, primary mother liquor tank 3, and secondary mother liquor tank 10 are all existing devices in the chemical industry, and the connection method between each device using pipelines is also existing technology. The specific structure and pipeline connection method will not be described in detail in this article.
[0020] The working principle of this embodiment is as follows:
[0021] During mother liquor treatment, the valve on the mother liquor feed pipe is opened, and the mother liquor enters the primary centrifuge 1. The primary centrifuge 1 is started, and the mother liquor after the first centrifugation enters the first half of the primary sedimentation tank 2. When the mother liquor level is higher than the overflow plate, the mother liquor flows to the second half of the primary sedimentation tank 2. After the primary sedimentation tank 2 discharges, the mother liquor enters the primary mother liquor tank 3. The vacuum pump 11 is started to evacuate the coarse steaming kettle 4, so that the mother liquor in the primary mother liquor tank 3 is vacuum fed. Steam is introduced into the jacket of the coarse steaming kettle. Vacuum distillation is performed. The gaseous material enters the condenser 5 for cooling and condensation, and then enters the solvent tank 6. The material in the solvent tank 6 is transported to the distillation column for subsequent distillation. The bottom liquid of the crude distillation vessel 4 enters the buffer tank 7. Then, the mother liquor in the buffer tank 7 is passed into the secondary centrifuge 8 for centrifugation. The mother liquor after the secondary centrifugation enters the secondary sedimentation tank 9. After multi-stage sedimentation, it enters the secondary mother liquor tank 10. The material in the secondary mother liquor tank 10 is pumped into the distillation column for subsequent distillation.
Claims
1. A mother liquor treatment system for the production of 4,4'-diaminodiphenyl ether, comprising a primary centrifuge (1), a crude distillation vessel (4), and a secondary centrifuge (8), wherein the inlet of the primary centrifuge (1) is connected to the mother liquor inlet pipe, characterized in that: The liquid outlet of the primary centrifuge (1) is connected to the inlet of the primary sedimentation tank (2) via a pipe. The outlet of the primary sedimentation tank (2) is connected to the inlet of the crude distillation vessel (4) via a pipe. The crude distillation vessel (4) is connected to the vacuum pump (11) via a pipe. The gas outlet of the crude distillation vessel (4) is connected to the condenser (5) via a pipe, and the liquid outlet is connected to the buffer tank (7) via a pipe. The outlet of the condenser (5) is connected to the inlet of the solvent tank (6). The outlet of the buffer tank (7) is connected to the inlet of the secondary centrifuge (8) via a pipe. The liquid outlet of the secondary centrifuge (8) is connected to the inlet of the secondary sedimentation tank (9) via a pipe. The outlets of the solvent tank (6) and the secondary sedimentation tank (9) are both connected to the distillation feed pipe via pipes.
2. The 4,4'-oxydianiline production mother liquor treatment system of claim 1, wherein: An overflow plate is fixedly connected in the middle of the primary sedimentation tank (2), and three overflow plates with progressively decreasing heights are fixedly connected at intervals from the inlet to the outlet inside the secondary sedimentation tank (9).
3. The 4,4'-oxydianiline production mother liquor treatment system of claim 1, wherein: The outlet of the primary sedimentation tank (2) is connected to the inlet of the primary mother liquor tank (3) via a pipe, and the outlet of the primary mother liquor tank (3) is connected to the inlet of the coarse steaming kettle (4) via a pipe.
4. The 4,4'-oxydianiline production mother liquor treatment system of claim 3, wherein: The outlet of the secondary sedimentation tank (9) is connected to the inlet of the secondary mother liquor tank (10) via a pipe, and the outlet of the secondary mother liquor tank (10) is connected to the distillation feed pipe via a pipe.
5. The 4,4'-oxydianiline production mother liquor treatment system of claim 4, wherein: Valves are connected to the pipelines between the primary centrifuge (1) and the primary sedimentation tank (2), the primary sedimentation tank (2) and the primary mother liquor tank (3), the primary mother liquor tank (3) and the crude distillation kettle (4), the crude distillation kettle (4) and the vacuum pump (11), the crude distillation kettle (4) and the condenser (5), the condenser (5) and the solvent tank (6), the crude distillation kettle (4) and the buffer tank (7), the buffer tank (7) and the secondary centrifuge (8), the secondary centrifuge (8) and the secondary sedimentation tank (9), the secondary sedimentation tank (9) and the secondary mother liquor tank (10), the secondary mother liquor tank (10) and the distillation feed pipe, and the solvent tank (6) and the distillation feed pipe.
6. The 4,4'-oxydianiline production mother liquor treatment system of claim 4, wherein: A delivery pump is connected to the pipeline between the secondary mother liquor tank (10) and the distillation feed pipe, and between the solvent tank (6) and the distillation feed pipe.