A bisphenol a anion regeneration system
By setting up a reverse flow pipeline and a nitrogen-assisted unit in the anion exchange bed, combined with the synergistic effect of phenol and caustic soda solution, the catalyst can be regenerated, solving the shutdown problem caused by catalyst failure in the anion exchange bed. This enables multiple recycling of the catalyst and continuous production, reducing costs and waste disposal.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LIAOCHENG LUXI POLYCARBONATE CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-06-19
AI Technical Summary
In existing technologies, the adsorption capacity of anion exchange beds is limited. As the operating time increases, their active sites are gradually occupied by sulfonate ions, leading to catalyst failure, uncontrolled system acidity, and forcing the unit to shut down to replace the catalyst, resulting in huge production losses and solid waste pollution problems.
A bisphenol A anion regeneration system was designed. By setting up a reverse flow pipeline and a nitrogen-assisted unit in the anion bed, and combining the synergistic effect of phenol and caustic soda solution, the catalyst is regenerated. The process includes phenol solution replacement, treatment with 5% caustic soda solution, and final phenol solution washing to restore catalyst activity.
It significantly extends the service life of the catalyst, avoids the cost of frequent catalyst replacement, improves production continuity and equipment utilization, reduces waste treatment costs, increases effective working hours, and improves economic benefits.
Smart Images
Figure CN224371491U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of chemical technology, specifically to a bisphenol A anion regeneration system. Background Technology
[0002] In the industrial production of bisphenol A (BPA), phenol and acetone are introduced into a reactor at a specific molar ratio and catalytically condensed to produce BPA using an acidic catalyst (such as a sulfonic acid ion exchange resin). The core of this process lies in the stability of the catalyst; however, in actual operation, the sulfonic acid groups (-SO3H) on the resin catalyst are prone to detachment. These detached sulfonic acid groups, after entering subsequent systems with the materials, not only catalyze side reactions to generate colored impurities such as quinones and polyphenols, but also trigger isomerization or degradation of the BPA molecule, leading to a darker product color and directly affecting the product's optical purity and application performance.
[0003] To address this issue, the mainstream process currently incorporates an anion exchange bed system downstream of the reactor. This device is filled with a weakly basic anion exchange resin, which adsorbs free sulfonate ions and acidic byproducts through its basic groups, thereby neutralizing the acidity of the system, inhibiting the chain reaction of pigment formation, and ensuring that the color of bisphenol A meets the standards.
[0004] However, this approach suffers from a significant bottleneck: the adsorption capacity of the weakly basic resin is limited, and as operating time increases, its active sites are gradually occupied by sulfonate ions, leading to a continuous decline in adsorption efficiency. This deactivation stems not only from physical adsorption saturation but also from chemical poisoning and mechanical damage to the resin structure caused by long-term swelling / shrinkage. Once the anion exchange bed fails, the uncontrolled acidity of the system will force the unit to shut down and replace the catalyst. Each replacement requires a significant amount of time, involving multiple steps such as equipment isolation, cleaning, unloading, activation of the new catalyst, and system restart. This not only results in substantial production losses but also necessitates the treatment of solid waste pollution from the waste resin. Therefore, there is an urgent need to develop a new system and corresponding process to address the current production predicament. Utility Model Content
[0005] To address the problem of catalyst failure in anion exchange beds leading to system shutdowns for replacement, resulting in huge production losses and solid waste pollution.
[0006] This utility model provides a bisphenol A anion regeneration system, including an anion bed, the inlet pipe of which is connected to a demineralized water inlet pipe, a phenol inlet pipe and a caustic soda inlet pipe respectively; the anion bed is provided with a top vent pipe and a bottom vent pipe, and a reverse flow pipe is provided to connect the inlet pipe and the bottom vent pipe, the upper end inlet of the bottom vent pipe being higher than the upper surface of the anion bed.
[0007] As a preferred embodiment, the inlet pipe is connected to a nitrogen inlet pipe, and the nitrogen inlet pipe is equipped with a nitrogen inlet valve.
[0008] As a preferred embodiment, the top vent pipe is equipped with a sight glass.
[0009] As a preferred embodiment, the demineralized water inlet pipe is equipped with a demineralized water inlet valve, the phenol inlet pipe is equipped with a phenol inlet valve, the caustic soda inlet pipe is equipped with a caustic soda inlet valve, the top vent pipe is equipped with a top vent valve, and the bottom vent pipe is equipped with a bottom vent valve.
[0010] As a preferred embodiment, the reverse flow pipeline is equipped with a backwash valve, which is a double-layer valve.
[0011] As a preferred embodiment, an inlet valve is installed in the inlet pipeline between the nitrogen inlet pipe and the reverse flow pipeline.
[0012] The method of using the bisphenol A anion regeneration system includes the following steps:
[0013] S1. Close the anion bed feed shut-off valve, open the phenol inlet valve and use phenol solution to replace the anion bed until the bisphenol A content in the anion bed is reduced to below 3%, then close the phenol inlet valve; after the phenol replacement is completed, open the demineralized water inlet valve and use demineralized water with a conductivity of less than 50 μS / cm at 65-75℃ to replace the anion bed catalyst until the conductivity of the demineralized water discharged from the bottom vent pipe is less than 50 μS / cm, then close the demineralized water inlet valve;
[0014] S2. Open the caustic soda inlet valve and backwash valve, close the inlet valve and bottom vent valve, and use a 5% caustic soda solution to replace the anion exchange bed. Observe that the caustic soda liquid level is 10-20cm above the catalyst liquid level. Close the caustic soda inlet valve and soak the catalyst for 24 hours. Then, open the bottom vent valve to discharge the caustic soda solution. After the caustic soda regeneration is completed, open the demineralized water inlet valve and use demineralized water with a conductivity of less than 50us / cm at 65-75℃ to replace the anion exchange bed catalyst. Make the conductivity of the demineralized water discharged from the bottom vent pipe less than 50us / cm or the pH between 7 and 9. Then, close the demineralized water inlet valve.
[0015] S3. Close the bottom vent valve, open the phenol inlet valve and the top vent valve, add phenol solution until phenol solution appears at the sight glass, then close the backwash valve and open the inlet valve and the bottom vent valve. Use phenol solution to replace the anion bed catalyst, so that the bisphenol A content in the anion bed is reduced to below 3% to complete the replacement, and then close the phenol inlet valve.
[0016] As a preferred option, after closing the anion bed feed shut-off valve, the material inlet pipe is connected to the crystallization system to avoid system shutdown.
[0017] As a preferred method, when replacing the anion exchange bed catalyst with desalinated water, open the desalinated water inlet valve, backwash valve, and top vent valve, close the inlet valve and bottom vent valve, add caustic soda solution until desalinated water appears at the sight glass, close the backwash valve and open the inlet valve and bottom vent valve, and then replace the anion exchange bed catalyst with the desalinated water solution.
[0018] As a preferred option, before replacing the anion exchange bed catalyst with demineralized water, the nitrogen inlet valve is opened to use nitrogen to force the solution out of the anion exchange bed, thereby reducing the amount of demineralized water used.
[0019] The beneficial effects of this utility model are as follows:
[0020] This invention utilizes the synergistic effect of phenol and caustic soda to regenerate the catalyst in an anion exchange bed, enabling it to be recycled multiple times. First, the anion exchange bed is replaced with a phenol solution to dissolve and remove residual bisphenol A solids and high-concentration solutions from the catalyst surface and pores. The bisphenol A content is reduced to below 3% to prevent residual bisphenol A from reacting with the alkali solution in subsequent steps to form viscous sodium bisphenol A salts, thus avoiding equipment blockage or affecting the regeneration effect.
[0021] Then, the chemical regeneration stage begins, where a 5% caustic soda solution is used to treat the anion exchange bed. Hydroxide ions in the caustic soda undergo an ion exchange reaction with bisphenol A anions adsorbed on the catalyst's active sites, desorbing the deactivated sodium bisphenol A and restoring the catalyst's activity.
[0022] Finally, the regenerated and cleaned catalyst bed is replaced again with a phenol solution. This ensures the system is filled with phenol, preparing it for restarting production, and further removes any remaining trace impurities, ultimately reducing the bisphenol A content in the bed to below 3% again, completing the entire regeneration process.
[0023] This invention significantly extends the service life of expensive anionic catalysts. Through cyclic regeneration, the enormous cost of frequent catalyst replacement is avoided. Simultaneously, the phenol solution used in the regeneration process can be recycled, and the waste alkali solution can be centrally treated or partially recovered, further reducing material consumption and waste disposal costs. Furthermore, during regeneration, material is introduced into the crystallization system via valve switching, avoiding shutdowns of the entire production system, ensuring production continuity, and improving equipment utilization and overall economic efficiency. Attached Figure Description
[0024] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...
[0025] Figure 1 This is a schematic diagram of the structure of this utility model;
[0026] Numbering on the map:
[0027] 1. Anion exchange bed; 2. Demineralized water inlet valve; 3. Phenol inlet valve; 4. Inlet valve; 5. Bottom vent valve; 6. Backwash valve; 7. Nitrogen inlet valve; 8. Caustic soda inlet valve; 11. Top vent valve; 12. Sight glass; 13. Reverse flow pipeline. Detailed Implementation
[0028] To illustrate the features of this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will further explain this utility model.
[0029] Example:
[0030] Please refer to the following: Figure 1 This utility model embodiment provides a bisphenol A anion regeneration system. The inlet manifold of the core equipment, the anion bed 1, is connected to three key media pipelines through a multi-channel diversion device: the desalination water inlet pipe is equipped with a pneumatically adjustable desalination water inlet valve 2, used to inject high-purity desalination water with a temperature precisely controlled within the range of 65-75℃ and a conductivity of less than 50μS / cm; the phenol inlet pipe is equipped with a phenol corrosion-resistant phenol inlet valve 3, used to inject fresh phenol solution without leakage; and the caustic soda inlet pipe is equipped with a caustic soda inlet valve 8, used to inject a 5% concentration caustic soda solution.
[0031] The vent pipe at the bottom of the anion bed 1 has an inverted U-shaped inlet extending 30cm above the upper surface of the anion bed 1 to effectively prevent catalyst loss. A bottom vent valve 5 with a pressure sensor is installed at the end to monitor the back pressure of the drain liquid in real time and prevent bed collapse. The key innovation lies in the configuration of a reverse flow pipe 13, which connects the inlet main pipe to the bottom vent pipe in reverse order, and is equipped with a backwash valve 6 with double mechanical seals. Under an operating pressure of 6.0MPa, the leakage rate is less than 0.001%, completely eliminating the risk of leakage due to corrosion from strong alkaline media.
[0032] In addition, this embodiment adds a nitrogen auxiliary unit, connecting a high-pressure nitrogen inlet pipe to the main inlet pipe section, equipped with a nitrogen inlet valve 7 and an integrated 0.5MPa constant pressure regulator, which can efficiently press out residual liquid at the end of regeneration. At the critical node between the nitrogen inlet pipe and the reverse flow pipeline 13, an inlet valve 4 is specially designed as the flow direction control center, working in conjunction with the backwash valve 6 and the bottom vent valve 5 to form a three-in-one flow direction control system, realizing seamless switching between three modes: bidirectional cleaning (co-current and counter-current), bidirectional regeneration (co-current and counter-current), and nitrogen-pressurized liquid. This design is remotely controlled via a hydraulic actuator, with a response time of less than 0.5 seconds.
[0033] This embodiment achieves a catalyst activity recovery rate of 98.7% through precise flow management, reducing the regeneration cycle from 32 hours in the traditional process to 23 hours. The online monitoring system integrates closed-loop control with dual pH and conductivity probes, ensuring stable effluent parameters within the optimal range of pH=7.5±0.3 and conductivity 48±3μS / cm. During regeneration, the entire equipment maintains continuous operation of the main unit through pipeline switching, increasing annual effective working hours by approximately 380 hours and raising the organic matter recovery rate in wastewater to 92%, significantly reducing hazardous waste treatment costs.
[0034] The method of using the bisphenol A anion regeneration system in this embodiment includes the following steps:
[0035] S1. Initial Permutation Phase:
[0036] Close the anion exchange bed feed shut-off valve and switch the raw material pipeline to the crystallization system to maintain continuous production. Open the phenol inlet valve 3 and continuously inject phenol solution into the anion exchange bed 1, reducing the bisphenol A concentration in the bed to below 3% through liquid-phase displacement. After phenol displacement is completed, start the demineralized water cleaning procedure: simultaneously open the demineralized water inlet valve 2, backwash valve 6, and top vent valve 11, injecting high-temperature demineralized water (conductivity strictly controlled below 50 μS / cm) at 65-75℃ into the system until a stable liquid level is observed in the sight glass 12. Then close the backwash valve 6, open the inlet valve 4 and the bottom vent valve 5 to form a co-current channel, and continue flushing until the conductivity of the discharged water is below the 50 μS / cm threshold.
[0037] S2. Alkali regeneration stage:
[0038] Open the caustic soda inlet valve 8 and backwash valve 6, and close the inlet valve 4 and bottom vent valve 5. Inject a 5% caustic soda solution into the system, and precisely monitor the liquid level rise process through the sight glass 12 to ensure that the caustic soda solution covers 10-20 cm above the catalyst bed. Close the caustic soda inlet valve 8 and allow for 24 hours of static soaking to fully restore the catalyst activity with hydroxide ions. After soaking, open the bottom vent valve 5 to drain the waste caustic soda solution, and then start the nitrogen inlet valve 7 to use 0.3-0.5 MPa nitrogen to force out the residual liquid in the bed, significantly reducing the subsequent cleaning water consumption. Finally, perform a second cleaning with demineralized water according to the operating procedures of Stage 1 until the discharged water meets the qualified standards of conductivity <50 μS / cm or pH value 7-9.
[0039] S3. Final Activation Stage:
[0040] Close the bottom vent valve 5 and open the phenol inlet valve 3 and the top vent valve 11. After the phenol solution is injected until a clear liquid level appears in the sight glass 12, close the backwash valve 6 and simultaneously open the inlet valve 4 and the bottom vent valve 5 to establish a forward flow path. Continue phenol replacement until the bisphenol A content in the bed stabilizes below 3%, and finally close the phenol inlet valve 3 to complete the entire catalyst regeneration process.
[0041] This embodiment utilizes the synergistic effect of phenol and caustic soda to regenerate the catalyst in the anion exchange bed, enabling it to be recycled multiple times. First, the anion exchange bed is replaced with a phenol solution to dissolve and remove residual bisphenol A solids and high-concentration solutions from the catalyst surface and pores. The bisphenol A content is reduced to below 3% to prevent residual bisphenol A from reacting with the alkali solution in subsequent steps to form viscous sodium bisphenol A salts, thus avoiding equipment blockage or affecting the regeneration effect.
[0042] Then, the chemical regeneration stage begins, where a 5% caustic soda solution is used to treat the anion exchange bed. Hydroxide ions in the caustic soda undergo an ion exchange reaction with bisphenol A anions adsorbed on the catalyst's active sites, desorbing the deactivated sodium bisphenol A and restoring the catalyst's activity.
[0043] Finally, the regenerated and cleaned catalyst bed is replaced again with a phenol solution. This ensures the system is filled with phenol, preparing it for restarting production, and further removes any remaining trace impurities, ultimately reducing the bisphenol A content in the bed to below 3% again, completing the entire regeneration process.
[0044] This invention significantly extends the service life of expensive anionic catalysts. Through cyclic regeneration, the enormous cost of frequent catalyst replacement is avoided. Simultaneously, the phenol solution used in the regeneration process can be recycled, and the waste alkali solution can be centrally treated or partially recovered, further reducing material consumption and waste disposal costs. Furthermore, during regeneration, material is introduced into the crystallization system via valve switching, avoiding shutdowns of the entire production system, ensuring production continuity, and improving equipment utilization and overall economic efficiency.
[0045] The above embodiments and accompanying drawings are only used to illustrate the technical solutions of this utility model and are not intended to limit this utility model. This utility model has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of this utility model do not depart from the spirit of this utility model and should also fall within the protection scope of the claims of this utility model. Other related technical structures not disclosed in detail in this utility model are existing technologies in the art.
Claims
1. A bisphenol A anion regeneration system, comprising an anion bed (1), characterized in that: The inlet pipe of the anion bed (1) is connected to the demineralized water inlet pipe, the phenol inlet pipe and the caustic soda inlet pipe respectively; the anion bed (1) is provided with a top vent pipe and a bottom vent pipe, and a reverse flow pipe (13) is provided to connect the inlet pipe and the bottom vent pipe, wherein the upper inlet of the bottom vent pipe is higher than the upper surface of the anion bed (1).
2. The bisphenol A anion regeneration system according to claim 1, characterized in that: The inlet pipe is connected to the nitrogen inlet pipe, and the nitrogen inlet pipe is equipped with a nitrogen inlet valve (7).
3. The bisphenol A anion regeneration system according to claim 1, characterized in that: The top vent pipe is equipped with a sight glass (12).
4. The bisphenol A anion regeneration system according to claim 1, characterized in that: The demineralized water inlet pipe is equipped with a demineralized water inlet valve (2), the phenol inlet pipe is equipped with a phenol inlet valve (3), the caustic soda inlet pipe is equipped with a caustic soda inlet valve (8), the top vent pipe is equipped with a top vent valve (11), and the bottom vent pipe is equipped with a bottom vent valve (5).
5. The bisphenol A anion regeneration system according to claim 1, characterized in that: The reverse flow pipeline (13) is equipped with a backwash valve (6), which is a double-layer valve.
6. The bisphenol A anion regeneration system according to claim 2, characterized in that: An inlet valve (4) is installed between the nitrogen inlet pipe and the reverse flow pipe (13).