Material returning device of polycarbonate reaction kettle
By designing a polycarbonate reactor recharge device, the problems of loss and separation difficulty of diphenyl carbonate and oligomers are solved by using gas phase recovery and multiple separation treatments, efficient recycling and reuse are achieved, and energy consumption is reduced.
Patent Information
- Application Number
- CN202421720668.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-07-19
AI Technical Summary
In the exchange synthesis process of polycarbonate, diphenyl carbonate and oligomers are brought out through the gas phase, resulting in increased loss and separation difficulty, and the energy consumption required for separation in the prior art is higher.
A polycarbonate reactor recharge device is designed, and phenol and oligomers are recovered by gas phase through the linkage of the primary prepolymerization reactor and the phenol recovery tower, and the diphenyl carbonate and oligomers are recovered and reused through multiple separation and reflux pump circulation, heating and condensation treatment.
It effectively reduces the loss of diphenyl carbonate and oligomers, increases the single-pass yield of polycarbonate plants, and reduces the energy consumption required for cyclic separation of diphenyl carbonate.
Smart Images
Figure CN222943443U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of polycarbonate synthesis, in particular to a material returning device for a polycarbonate reaction kettle. Background Art
[0002] In the process of synthesizing polycarbonate by melt ester exchange of bisphenol A and diphenyl carbonate, phenol is produced as a by-product of the reaction and is carried out of the reactor by the gas phase to promote the polymerization reaction of bisphenol A and diphenyl carbonate.
[0003] The reaction formula for the polymerization of diphenyl carbonate and bisphenol A to produce polycarbonate is as follows:
[0004] .
[0005] Since the prepolymerization reactor temperature is generally 220-240°C and is carried out under vacuum conditions, diphenyl carbonate and some oligomers will be carried out with the gas phase, resulting in the loss of diphenyl carbonate and oligomers in the reaction system. In the prior art, the mixture of diphenyl carbonate and oligomers is generally separated and the diphenyl carbonate is recovered for recycling, which increases the energy consumption required for separation. Summary of the invention
[0006] The technical problem to be solved by the utility model is to provide a polycarbonate reaction kettle material returning device, which can recycle most of the mixture of diphenyl carbonate and oligomers and reduce the loss of diphenyl carbonate and oligomers.
[0007] In order to solve the above technical problems, the technical solution adopted by the utility model is: a polycarbonate reactor return device, comprising a primary prepolymerization reactor, the material outlet at the bottom of the primary prepolymerization reactor is transported to the secondary prepolymerization reactor through a pipeline, the gas phase outlet at the top of the primary prepolymerization reactor is connected to a phenol recovery tower through a pipeline, the gas phase outlet at the top of the phenol recovery tower is connected to a condenser and a phenol recovery tower reflux tank through a pipeline, the discharge port at the bottom of the phenol recovery tower is connected to a phenol recovery tower circulation pump through a circulation pipeline, and a heat exchanger, the discharge end of the circulation pipeline is connected to the phenol recovery tower, the drain pipe is connected to the circulation pipeline, the connection position of the drain pipe and the circulation pipeline is set downstream of the circulation pump of the phenol recovery tower, the drain pipe is provided with a discharge valve, the discharge port of the reflux tank of the phenol recovery tower is connected to the phenol reflux pump and the phenol recovery tower in sequence through the reflux pipeline, the phenol recovery pipeline is connected to the reflux pipeline, the connection position of the phenol recovery pipeline and the reflux pipeline is set downstream of the phenol reflux pump, and the phenol recovery pipeline is provided with a phenol recovery control valve.
[0008] In a preferred embodiment, the circulation pipeline is connected to the reflux branch, the reflux branch is connected to the feed port of the primary prepolymerization reactor, the connection position of the reflux branch and the circulation pipeline is set downstream of the phenol recovery tower circulation pump, and a regulating valve is provided on the reflux branch.
[0009] In a preferred solution, a flow meter is provided on the reflux branch.
[0010] The utility model provides a polycarbonate reactor material return device, which has the following beneficial effects:
[0011] 1. The phenol, diphenyl carbonate and oligomers produced by the polymerization reaction in the primary prepolymerization reactor enter the phenol recovery tower through the gas phase. The phenol discharged from the top of the phenol recovery tower enters the reflux tank of the phenol recovery tower after condensation in the cooler. The reflux tank of the phenol recovery tower returns the material to the phenol recovery tower through the reflux pipeline and the phenol reflux pump to be connected, and phenol is separated from diphenyl carbonate and oligomers for multiple times, thereby reducing the content of diphenyl carbonate and oligomers in phenol.
[0012] 2. The remaining diphenyl carbonate and oligomers in the phenol recovery tower are discharged to the exhaust collection tank through the exhaust pipe or refluxed to the primary prepolymerization reactor for reuse, replenishing the diphenyl carbonate and oligomers lost in the reaction system and increasing the single-pass output of the polycarbonate unit.
[0013] 3. Reduce the energy consumption required for the recycling and separation of diphenyl carbonate. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments:
[0015] Figure 1 It is a structural schematic diagram of the utility model;
[0016] In the figure: a primary prepolymerization reactor 1, a phenol recovery tower 2, a condenser 3, a phenol recovery tower reflux tank 4, a circulation pipeline 5, a phenol recovery tower circulation pump 6, a heat exchanger 7, a drain pipe 8, a discharge valve 9, a reflux pipeline 10, a phenol reflux pump 11, a phenol recovery pipeline 12, a phenol recovery control valve 13, a reflux branch 14, a regulating valve 15, and a flow meter 16. DETAILED DESCRIPTION
[0017] like Figure 1As shown, a polycarbonate reactor return device comprises a primary prepolymerization reactor 1, the material outlet at the bottom of the primary prepolymerization reactor 1 is transported to a secondary prepolymerization reactor through a pipeline, the gas phase outlet at the top of the primary prepolymerization reactor 1 is connected to a phenol recovery tower 2 through a pipeline, the gas phase outlet at the top of the phenol recovery tower 2 is connected to a condenser 3 and a phenol recovery tower reflux tank 4 through pipelines in sequence, the discharge port at the bottom of the phenol recovery tower 2 is connected to a phenol recovery tower circulation pump 6 and a heat exchanger 7 through a circulation pipeline 5 in sequence, the discharge end of the circulation pipeline 5 is connected to the phenol recovery tower 2, and the discharge port of the phenol recovery tower 2 is connected to the phenol recovery tower 2 through a circulation pipeline 5. The recovery tower 2 is connected, the drain pipe 8 is connected to the circulation pipeline 5, the connection position of the drain pipe 8 and the circulation pipeline 5 is set downstream of the phenol recovery tower circulation pump 6, and a discharge valve 9 is provided on the drain pipe 8. The discharge port of the phenol recovery tower reflux tank 4 is connected to the phenol reflux pump 11 and the phenol recovery tower 2 in sequence through the reflux pipeline 10. The phenol recovery pipeline 12 is connected to the reflux pipeline 10, and the connection position of the phenol recovery pipeline 12 and the reflux pipeline 10 is set downstream of the phenol reflux pump 11. The phenol recovery pipeline 12 is provided with a phenol recovery control valve 13.
[0018] Phenol, diphenyl carbonate and oligomers produced by the polymerization reaction enter the phenol recovery tower 2 through the gas phase, and the liquid phase in the phenol recovery tower 2 is transported to the heat exchanger 7 through the phenol recovery tower circulation pump 6 for circulation heating. The phenol discharged from the top of the phenol recovery tower 2 enters the phenol recovery tower reflux tank 4 after condensation by the cooler 3. Since the phenol discharged from the top of the phenol recovery tower 2 is mixed with diphenyl carbonate, the phenol recovery tower reflux tank 4 is connected to the phenol reflux pump 11 and the phenol recovery tower 2 in sequence through the reflux pipeline 10 to separate phenol and diphenyl carbonate again, until the purity of the phenol in the phenol recovery tower reflux tank 4 reaches the set standard and is discharged from the phenol recovery pipeline 12.
[0019] Preferably, the circulation pipeline 5 is connected to the reflux branch 14, and the reflux branch 14 is connected to the feed port of the primary prepolymerization reactor 1. Specifically, the reflux branch 14 can be connected to the primary prepolymerization reactor 1 after merging with the feed pipe of the primary prepolymerization reactor 1. The connection position of the reflux branch 14 and the circulation pipeline 5 is set downstream of the phenol recovery tower circulation pump 6. The reflux branch 14 is provided with a regulating valve 15. The regulating valve 15 is provided to facilitate the adjustment of the amount of diphenyl carbonate and oligomers returned from the reflux branch 14 to the primary prepolymerization reactor 1.
[0020] During specific use, a flow meter 16 is provided on the reflux branch 14 to adjust the flow rate flowing into the reflux branch 14 .
[0021] The mixture of diphenyl carbonate and oligomers not containing phenol is fed back to the primary prepolymerization reactor 1 through the provided reflux branch 14 for reuse, so as to replenish the diphenyl carbonate and oligomers lost in the reaction system.
[0022] The working process of this device is as follows:
[0023] Bisphenol A and diphenyl carbonate slurry enter the primary prepolymerization reactor 1, and phenol, diphenyl carbonate and oligomers produced by the polymerization reaction enter the phenol recovery tower 2 through the gas phase discharge port. The materials of the phenol recovery tower 2 are circulated and transported through the phenol recovery tower circulation pump 6. During the circulation process, the heat exchanger 7 is heated. The phenol gas phase at the top of the phenol recovery tower 2 is condensed by the condenser 3 and enters the phenol recovery tower reflux tank 4. The phenol in the phenol recovery tower reflux tank 4 is refluxed to the phenol recovery tower 2 through the phenol reflux pump 11, so as to improve the purity of phenol in the phenol recovery tower reflux tank 4 and prevent diphenyl carbonate from being brought into the phenol recovery tower reflux tank 4. After the purity of phenol in the phenol recovery tower reflux tank 4 reaches 99%wt, the phenol recovery control valve 13 is opened, and the phenol is sent to the phenol recovery system through the phenol reflux pump 11 and the phenol recovery pipeline 12.
[0024] The material in the bottom of the phenol recovery tower 2 is continuously circulated by the phenol recovery tower circulation pump 6 and heated by the heat exchanger 7, and continuously refluxed and refined. The discharge valve 9 is opened, and the mixture of diphenyl carbonate and oligomers remaining in the bottom of the tower is sent to the exhaust collection tank by the phenol recovery tower circulation pump 6 and the discharge pipe 8.
[0025] After the material sent out by the circulating pump 6 of the phenol recovery tower is analyzed and tested to be free of phenol, the regulating valve 15 is opened, and the material is returned through the reflux branch 14, and returned to the primary prepolymerization reactor 1 together with the bisphenol A and diphenyl carbonate slurry feed. The material in the primary prepolymerization reactor 1 is analyzed, and the regulating valve 15 is adjusted to meet the molar ratio n (diphenyl carbonate): n (bisphenol A) between 1.1 and 1.3. The mixture of excess diphenyl carbonate and oligomers discharged from the phenol recovery tower 2 is sent to the exhaust collection tank through the exhaust pipe 8.
[0026] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.
Claims
1. A polycarbonate reactor material return device, comprising a primary prepolymerization reactor (1), wherein the material outlet at the bottom of the primary prepolymerization reactor (1) is transported to a secondary prepolymerization reactor via a pipeline, and characterized in that: The gas phase outlet at the top of the first-stage prepolymerization reactor (1) is connected to the phenol recovery tower (2) through a pipeline, the gas phase outlet at the top of the phenol recovery tower (2) is connected to the condenser (3) and the phenol recovery tower reflux tank (4) in sequence through pipelines, the discharge port at the bottom of the phenol recovery tower (2) is connected to the phenol recovery tower circulation pump (6) and the heat exchanger (7) in sequence through a circulation pipeline (5), the discharge end of the circulation pipeline (5) is connected to the phenol recovery tower (2), the exhaust pipe (8) is connected to the circulation pipeline (5), and the exhaust pipe (8) is connected to the circulation pipeline ( The connection position of the phenol recovery tower circulation pump (5) is arranged downstream of the phenol recovery tower circulation pump (6), the discharge valve (9) is arranged on the discharge pipe (8), the discharge port of the phenol recovery tower reflux tank (4) is connected to the phenol reflux pump (11) and the phenol recovery tower (2) in sequence through the reflux pipeline (10), the phenol recovery pipeline (12) is connected to the reflux pipeline (10), the connection position of the phenol recovery pipeline (12) and the reflux pipeline (10) is arranged downstream of the phenol reflux pump (11), and the phenol recovery pipeline (12) is provided with a phenol recovery control valve (13).
2. A polycarbonate reactor material return device according to claim 1, characterized in that: The circulation pipeline (5) is connected to a reflux branch (14), and the reflux branch (14) is connected to a feed port of the first-stage prepolymerization reactor (1). The connection position between the reflux branch (14) and the circulation pipeline (5) is arranged downstream of a circulation pump (6) of a phenol recovery tower, and a regulating valve (15) is arranged on the reflux branch (14).
3. A polycarbonate reactor material return device according to claim 2, characterized in that: A flow meter (16) is provided on the reflux branch (14).