A method for solvent extraction of chlorine from epoxy resins

Abstract

The application relates to the technical field of epoxy resin refining treatment, and discloses a solvent extraction chlorine removal method for epoxy resin. The method comprises the following steps: mixing the epoxy resin to be treated and a main solvent to form a single-phase resin liquid, collecting liquid, loading an extractant, detecting and quantifying data such as unit quantity, calculating total chlorine to be removed, single-stage target chlorine load, load balance extraction phase ratio and unified extractant volume, establishing a multi-stage extraction path with resin phase in the same direction and extraction phase in the opposite direction, completing mixed phase separation, load calculation, qualification determination and vacuum desolventization, and obtaining low-chlorine epoxy resin. The method reduces experience setting, improves extractant dosage matching, process detectability and batch release reliability.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin refining technology, specifically to a solvent extraction method for dechlorination of epoxy resin. Background Technology

[0002] Epoxy resins are widely used in electronic packaging, copper-clad laminates, coatings, adhesives, and composite materials due to their excellent bonding, chemical resistance, and electrical insulation properties. For electronic, insulating, and high-reliability applications, the chlorine impurity content in epoxy resins directly affects the material's dielectric stability, resistance to damp heat, risk of metal corrosion, and long-term reliability. Therefore, dechlorination treatment is a crucial step in the epoxy resin refining process. Current methods for dechlorinating epoxy resins typically employ water washing, alkaline washing, adsorption, sedimentation separation, single-stage solvent extraction, or multiple repeated extractions. These methods reduce the chlorine content in the resin system by causing chlorine impurities to migrate into the aqueous phase, extraction phase, or adsorption medium.

[0003] Existing solvent extraction dechlorination processes largely rely on fixed extractant dosage, fixed stirring time, and empirical multiple extraction operations. They typically use the final chlorine content as the sole criterion, lacking a unified design for the total amount of chlorine to be removed, the chlorine load of each stage, the capacity of the extract phase, and the flow direction of materials at each stage. For epoxy resin solutions with high chlorine content or large batch-to-batch fluctuations, fixed-phase extraction can easily lead to excessively high chlorine load in the front-stage extraction stage and idle extraction capacity in the later stages, resulting in uneven chlorination contributions from each stage. When the extractant capacity is insufficient, the chlorine-rich extract phase may approach saturation, reducing the driving force for chlorine impurity migration, thus lowering subsequent extraction efficiency and even causing unstable final chlorine content. Furthermore, in existing multi-stage extraction processes, the resin and extract phase flows are often simply connected in series according to equipment layout, lacking a countercurrent carrying relationship based on chlorine mass load and an outlet load calculation mechanism, making it difficult to accurately determine whether the actual chlorine transfer amount at each stage meets expectations. If the decision to repeat extraction is based solely on the final test results, it not only increases solvent consumption and processing time but may also lead to resin loss, increased residual solvent, and a heavier burden on subsequent solvent removal due to over-extraction. For industrial continuous processing scenarios, existing processes still have problems such as insufficient matching between test data and actual extraction systems, significant impact of detection deviations on batch determination, and unclear criteria for handling qualified and unqualified batches.

[0004] Therefore, this case aims to propose a solvent extraction method for dechlorination of epoxy resin. First, basic parameters such as resin liquid volume, initial chlorine mass concentration, target chlorine mass concentration of the product, effective chlorine carrying capacity of the extractant, and chlorine concentration corresponding to the detection limit of quantitation are established. Then, the target chlorine load of each stage is allocated according to the total amount of chlorine to be removed, and the target inlet and outlet chlorine mass concentrations of the resin phase in each extraction stage are determined accordingly, as well as the load-balanced extraction ratio, the uniform extractant volume throughout the process, and the actual extraction ratio. Summary of the Invention

[0005] This invention provides a solvent extraction method for dechlorinating epoxy resin, which helps to solve the problems mentioned in the background art.

[0006] This invention provides the following technical solution: a method for solvent extraction and dechlorination of epoxy resin, comprising: The epoxy resin to be treated is mixed with the main solvent to form a single-phase resin solution. The mass, density, initial and target chlorine mass concentration of the resin solution, extractant loading test, detection quantification and number of units are collected to obtain the resin solution volume, extractant effective chlorine loading concentration and chlorine concentration corresponding to the detection quantification limit. Calculate the total amount of chlorine to be removed based on the initial and target chlorine mass concentrations and the resin liquid volume, determine the number of extraction stages, and generate the target chlorine load for each stage and the target inlet and outlet chlorine mass concentrations of the resin phase for each extraction stage. The load balance extraction was calculated based on the remaining amount of chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of a single stage, and the unified extractant volume throughout the process was formed by combining the effective chlorine carrying capacity of the extractant with the actual extraction volume. Establish a path for the resin phase to flow in the forward direction and the extract phase to flow in the counter-current direction, so that the fresh extractant enters the mixing and phase separation unit corresponding to the final extraction stage, and the extract phase other than the first extraction stage moves into the mixing and phase separation unit corresponding to the adjacent previous extraction stage. Using the resin liquid volume and the unified extractant volume throughout the process as the effective volume of the two phases in each extraction stage, the resin phase outlet liquid and the chlorine-rich extract phase are output. The actual inlet and outlet chlorine mass concentrations of each extraction stage resin phase were detected and established. The actual chlorine transfer load and actual total chlorine transfer amount of each extraction stage were calculated, and the chlorine load of the extraction phase was recorded. Based on the resin liquid volume, the chlorine concentration corresponding to the detection limit, the volume of the extractant throughout the process, and the effective chlorine carrying capacity, the batches are balanced, qualified, monotonically dechlorinated, and the upper limit of carrying capacity are determined to form qualified or unqualified batches. Under qualified batch conditions, the chlorine-rich extraction phase is discharged, and the outlet liquid of the final extraction stage resin phase is desolvated under reduced pressure to obtain a low-chlorine epoxy resin product, thus forming the final chlorine mass concentration, final dechlorination rate, and extraction load results.

[0007] Optionally, the step of mixing the epoxy resin to be treated with the main solvent to form a single-phase resin solution, collecting the resin solution mass, density, initial and target chlorine mass concentration of the resin solution, extractant carrying capacity test, detection quantification, and number of units to obtain the resin solution volume, extractant effective chlorine carrying capacity, and chlorine concentration corresponding to the detection quantification limit, specifically includes: The epoxy resin to be treated is added to the main solvent and stirred to form a single-phase resin solution. The resin solution is then separated into a resin phase and an extract phase after contact with the extractant. Record the resin liquid mass and resin liquid density. Divide the resin liquid mass and resin liquid density by the resin liquid mass, with the resin liquid mass as the dividend and the resin liquid density as the divisor, to obtain the resin liquid volume. The initial chlorine concentration of the resin solution is detected, the target chlorine concentration of the product is set, and the initial chlorine concentration of the resin solution is limited to be higher than the target chlorine concentration of the product, while the target chlorine concentration of the product is limited to be no lower than zero. Extractant carrying capacity test was conducted according to the main solvent, extractant composition and phase separation conditions in the liquid-liquid contact system formed by resin and extractant. The volume and chlorine mass of the chlorine-rich extractant sample were collected after the carrying capacity endpoint was reached, and the volume and chlorine mass of the chlorine-rich extractant sample were limited to be greater than zero. Divide the chlorine mass of the chlorine-rich extractant sample by the volume of the chlorine-rich extractant sample, with the chlorine mass of the chlorine-rich extractant sample being the dividend and the volume of the chlorine-rich extractant sample being the divisor, to obtain the effective chlorine carrying capacity of the extractant. Read the minimum quantitative chlorine mass and detection sampling volume of the chlorine detection method, and limit the minimum quantitative chlorine mass and detection sampling volume of the chlorine detection method to be greater than zero; Divide the minimum quantitative chlorine mass of the chlorine detection method by the detection sampling volume, with the minimum quantitative chlorine mass of the chlorine detection method as the dividend and the detection sampling volume as the divisor, to obtain the chlorine concentration corresponding to the detection limit of quantitation; Read the number of serially connected hybrid phase separation units, use the number of serially connected hybrid phase separation units as the number of extraction stages, establish an extraction stage set from the first extraction stage to the last extraction stage according to the serial connection order, and set a corresponding extraction stage index for each extraction stage.

[0008] Optionally, the step of calculating the total amount of chlorine to be removed based on the initial and target chlorine mass concentrations and the resin feed volume, determining the number of extraction stages, and generating the target chlorine load for each stage and the target inlet and outlet chlorine mass concentrations for each extraction stage resin phase specifically includes: Read the resin liquid volume, the initial chlorine mass concentration of the resin liquid, and the target chlorine mass concentration of the product. Subtract the target chlorine mass concentration of the product from the initial chlorine mass concentration of the resin liquid to obtain the target chlorine reduction concentration. Multiply the target chlorine reduction concentration by the resin liquid volume to obtain the total amount of chlorine to be removed. The total amount of chlorine to be removed is evenly distributed according to the number of extraction stages to obtain the target chlorine load for each stage. Set the target inlet chlorine mass concentration of the first-stage extraction resin phase as the initial chlorine mass concentration of the resin feed solution. According to the extraction stage sequence from the first extraction stage to the last extraction stage, each extraction stage is marked with a corresponding stage number. The corresponding stage number is multiplied by the single-stage target chlorine load, and the product is divided by the resin liquid volume, with the product being the dividend and the resin liquid volume being the divisor, to obtain the cumulative target chlorine reduction concentration of the corresponding extraction stage. Subtract the cumulative target chlorine reduction concentration of the corresponding extraction stage from the initial chlorine mass concentration of the resin feed solution to obtain the target outlet chlorine mass concentration of the resin phase in the corresponding extraction stage; The decrease in the target outlet chlorine mass concentration of two adjacent extraction stage resin phases is limited to the concentration difference obtained by dividing the single-stage target chlorine load by the resin feed volume, and the target outlet chlorine mass concentration of the previous extraction stage resin phase is used as the target inlet chlorine mass concentration of the next extraction stage resin phase.

[0009] Optionally, the comparison between the load-balanced extraction calculated based on the remaining chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of a single stage, and the comparison between the extractant volume formed by the effective chlorine carrying capacity of the extractant and the actual extraction, specifically includes: For each extraction stage, calculate the target chlorine concentration to be reduced at the current extraction stage resin inlet based on the current target inlet chlorine concentration and the target chlorine concentration of the product. Multiply the current chlorine concentration to be reduced at the target inlet of the extraction-stage resin phase by the resin liquid volume to obtain the remaining amount of chlorine to be removed at the target inlet of the current extraction-stage resin phase. Divide the single-stage target chlorine load by the remaining amount of chlorine to be removed at the target inlet of the current extraction stage resin phase, with the single-stage target chlorine load as the dividend and the remaining amount of chlorine to be removed at the target inlet of the current extraction stage resin phase as the divisor, to obtain the current extraction stage load balanced extraction ratio; Divide the total amount of chlorine to be removed by the effective chlorine carrying capacity of the extractant, with the total amount of chlorine to be removed being the dividend and the effective chlorine carrying capacity of the extractant being the divisor, to obtain the total carrying capacity of the extractant volume for the entire process. The load equalization extraction ratio of each extraction stage is multiplied by the resin feed volume to obtain the load equalization required volume for the corresponding extraction stage. The maximum value between the total capacity limit of the extractant volume and the volume required for load balancing of all extraction stages is taken to obtain the uniform extractant volume for the entire process. Divide the volume of the uniform extractant throughout the process by the volume of the resin solution, with the volume of the uniform extractant throughout the process being the dividend and the volume of the resin solution being the divisor, to obtain the actual extraction comparison of the entire process. Multiply the volume of the extractant throughout the entire process by the effective chlorine carrying capacity of the extractant, and limit the product to be no less than the total amount of chlorine to be removed.

[0010] Optionally, establishing a co-current resin phase and counter-current extractive phase path, allowing fresh extractant to enter the mixing and phase-separation unit corresponding to the final extraction stage, and allowing the extractive phase (excluding the first extraction stage) to move into the mixing and phase-separation unit corresponding to the adjacent preceding extraction stage, specifically includes: The resin feed is fed into the mixing and phase separation unit corresponding to the first extraction stage, and flows through the mixing and phase separation units corresponding to each extraction stage in series order. After the resin feed solution completes the mixing and phase separation in the final extraction stage, the resin phase outlet feed solution of the final extraction stage is output from the corresponding mixing and phase separation unit of the final extraction stage. A blank chlorine load deduction was performed on the fresh extractant to form a fresh extractant stream after blank chlorine load deduction; The fresh extractant stream after blank chlorine load deduction is sent to the corresponding mixing and phase separation unit of the final extraction stage and serves as the inlet stream of the extraction phase of the final extraction stage. For each extraction stage except the first extraction stage, the extract phase output from the mixing and phase separation unit corresponding to the current extraction stage is sent to the mixing and phase separation unit corresponding to the adjacent previous extraction stage and used as the inlet stream of the extract phase of the adjacent previous extraction stage. The extraction phase output from the mixing and phase separation unit corresponding to the first extraction stage is used as the chlorine-rich extraction phase.

[0011] Optionally, the process of using the resin feed volume and the unified extractant volume throughout the process as the effective volume of the two phases in each extraction stage for mixing, contact, phase separation, and transfer, and outputting the final extraction stage resin phase outlet liquid and chlorine-rich extract phase, specifically includes: For each extraction stage, the resin phase entering the corresponding mixing and phase separation unit of the current extraction stage is metered, and the effective volume of the resin phase fed in is recorded as the effective volume of the resin phase in the current extraction stage. The effective volume of the resin phase in the current extraction stage is taken as the volume of the resin liquid. The extraction phase entering the mixing and phase separation unit corresponding to the current extraction stage is metered, and the effective volume of the extracted phase is recorded as the effective volume of the extraction phase in the current extraction stage. The effective volume of the extraction phase in the current extraction stage is taken as the volume of the extractant throughout the entire process, so that the resin liquid and the extractant form a liquid-liquid contact system in the mixing and phase separation unit corresponding to the current extraction stage. Read the mixed circulation flow rate and set the fixed number of mixed liquid changes to three; Add the current effective volume of the resin phase in the extraction stage to the current effective volume of the extraction phase in the extraction stage to obtain the total effective volume of single-stage contact in the current extraction stage. Multiply the total effective volume of single-stage contact in the current extraction stage by the fixed number of mixing and liquid exchange cycles, and then divide the product by the mixing circulation flow rate, with the product being the dividend and the mixing circulation flow rate being the divisor, to obtain the uniform mixing contact time. The resin feed and extractant are kept in continuous contact within a uniform mixing contact time, and the single-stage target chlorine load is used as the liquid-liquid contact design quantity for the current extraction stage corresponding to the mixing and phase separation unit. Multiply the effective volume of the extractant phase in the current extraction stage by the effective chlorine load concentration of the extractant to obtain the extractant phase load of the mixed phase separation unit corresponding to the current extraction stage, and verify that the extractant phase load of the mixed phase separation unit corresponding to the current extraction stage is not lower than the single-stage target chlorine load. After the mixing contact is complete, stop mixing and let stand until the resin phase and the extraction phase form a separable interface; The resin phase of each extraction stage, except the final extraction stage, is fed into the corresponding mixing and phase separation unit of the next adjacent extraction stage. The extract phase of each extraction stage except the first extraction stage is fed into the mixing and phase separation unit corresponding to the adjacent previous extraction stage. The final extraction stage resin phase outlet liquid is output from the mixing and phase separation unit corresponding to the final extraction stage, and the chlorine-rich extraction phase is output from the mixing and phase separation unit corresponding to the first extraction stage.

[0012] Optionally, the detection and establishment of the actual inlet and outlet chlorine mass concentrations of each extraction stage resin phase, the calculation of the actual transferred chlorine load and the actual total transferred chlorine amount of each extraction stage, and the recording of the extraction phase chlorine load specifically include: Samples were taken from the resin phase after each extraction stage phase separation, and the actual chlorine mass concentration at the outlet of the corresponding extraction stage resin phase was detected. The actual chlorine mass concentration at the outlet of the corresponding extraction stage resin phase was then limited to not less than zero. Based on the initial chlorine mass concentration of the resin feed and the actual chlorine mass concentration at the outlet of each extraction stage resin phase, a sequence of actual chlorine mass concentrations of the resin phase from the actual inlet of the first extraction stage resin phase to the actual outlet of the last extraction stage resin phase is established. The initial chlorine mass concentration of the resin feed is taken as the actual inlet chlorine mass concentration of the first extraction stage resin phase, and the actual outlet chlorine mass concentration of the adjacent preceding extraction stage resin phase is taken as the actual inlet chlorine mass concentration of the subsequent extraction stage resin phase. For each extraction stage, the actual chlorine concentration at the inlet of the resin phase of the current extraction stage is subtracted from the actual chlorine concentration at the outlet of the resin phase of the current extraction stage to obtain the actual chlorine reduction concentration of the current extraction stage. Multiply the actual chlorine reduction concentration in the current extraction stage by the resin liquid volume to obtain the current chlorine transfer candidate amount in the extraction stage; When the current chlorine transfer candidate quantity in the extraction stage is not less than zero, the current chlorine transfer candidate quantity in the extraction stage is recorded as the current actual chlorine transfer load in the extraction stage; when the current chlorine transfer candidate quantity in the extraction stage is less than zero, the current actual chlorine transfer load in the extraction stage is recorded as zero. For the fresh extractant stream after blank chlorine load deduction, the chlorine load at the inlet of the final extraction stage is recorded as zero; According to the order in which the extractant phase is countercurrently transferred from the final extraction stage to the first extraction stage, for each extraction stage from the final extraction stage to the second extraction stage, the inlet chlorine load of the extractant phase of the current extraction stage is added to the actual transferred chlorine load of the extractant phase of the current extraction stage to obtain the outlet chlorine load of the extractant phase of the current extraction stage. The chlorine load at the outlet of the extraction phase of each extraction stage from the last extraction stage to the second extraction stage is recorded as the chlorine load at the inlet of the extraction phase of the adjacent previous extraction stage. After the transfer of chlorine load at the inlet of the extraction phase from the second extraction stage to the first extraction stage is completed, the chlorine load at the inlet of the extraction phase of the first extraction stage is added to the actual transferred chlorine load of the extraction phase of the first extraction stage to obtain the chlorine load at the outlet of the extraction phase of the first extraction stage.

[0013] Optionally, the determination of whether a batch is qualified or unqualified is based on the resin liquid volume, the chlorine concentration corresponding to the detection limit of quantitation, the volume of the extractant throughout the process, and the effective chlorine carrying capacity, including balancing, compliance, monotonic dechlorination, and upper limit of carrying capacity, to form a qualified or unqualified batch. Multiply the resin liquid volume by the chlorine concentration corresponding to the detection limit to obtain the permissible deviation for a single load. For each extraction stage, an equilibrium determination is made regarding the actual transferred chlorine load. First, the difference between the current actual transferred chlorine load of the extraction stage and the target chlorine load of the single stage is calculated. Then, the absolute value of the difference is transformed to form the absolute value of the current extraction stage load difference. Finally, it is checked that the absolute value of the current extraction stage load difference is not greater than the allowable deviation of the single stage load. The actual chlorine mass concentration at the outlet of the final extraction stage resin phase is judged to meet the standard, and it is verified that the actual chlorine mass concentration at the outlet of the final extraction stage resin phase is not higher than the target chlorine mass concentration of the product. The actual chlorine transfer load of each extraction stage is added together to obtain the actual total chlorine transfer amount; Multiply the volume of the extractant throughout the entire process by the effective chlorine carrying capacity of the extractant to obtain the upper limit of the chlorine-rich extract phase carrying capacity. Then, determine the upper limit of the chlorine-rich extract phase carrying capacity and verify that the chlorine load at the outlet of the first-stage extract phase does not exceed the upper limit of the chlorine-rich extract phase carrying capacity. For each extraction stage, a monotonic dechlorination determination is performed on the actual inlet chlorine concentration and the actual outlet chlorine concentration of the resin phase. The actual inlet chlorine concentration of the current extraction stage resin phase is verified to be no lower than the actual outlet chlorine concentration of the current extraction stage resin phase. When the actual chlorine transfer load of each extraction stage passes the balance judgment, the monotonic dechlorination judgment of each extraction stage passes the judgment, the actual outlet chlorine mass concentration of the resin phase of the final extraction stage passes the standard judgment, and the outlet chlorine load of the extraction phase of the first extraction stage passes the upper limit judgment of the chlorine-rich extraction phase, it is recorded as a load balance qualified batch. If any of the following criteria are not met: balance determination, monotonous dechlorination determination, compliance determination, or upper limit determination of chlorine-rich extract phase load, it shall be recorded as a batch that fails to meet the load balance criteria and shall not be recorded as a release conclusion for low-chlorine epoxy resin products.

[0014] Optionally, the step of discharging the chlorine-rich extraction phase under qualified batch conditions, and then desolvating the final extraction stage resin phase outlet liquid under reduced pressure to obtain a low-chlorine epoxy resin product, thus forming the final chlorine mass concentration, final dechlorination rate, and extraction load results, specifically includes: Under the condition of load balance and qualified batch, the extract phase output from the mixing and phase separation unit corresponding to the first extraction stage is discharged as the chlorine-rich extract phase. Under the condition of a load-balanced qualified batch, the outlet liquid of the final extraction stage resin phase is retained as the low-chlorine resin liquid; Under load-balanced qualified batch conditions, the low-chlorine resin solution is subjected to desolventizing under reduced pressure to remove the main solvent and residual extractant, thereby obtaining the low-chlorine epoxy resin product. The actual outlet chlorine mass concentration of the final extraction stage resin phase is taken as the final chlorine mass concentration. Under the condition of load balance and qualified batch, the initial chlorine mass concentration of the resin solution is subtracted from the final chlorine mass concentration to obtain the final chlorine reduction concentration. The final chlorine reduction concentration is then divided by the initial chlorine mass concentration of the resin solution, with the final chlorine reduction concentration as the dividend and the initial chlorine mass concentration of the resin solution as the divisor, to obtain the final chlorine removal rate. Under the condition of load balance and qualified batch, the output is low-chlorine epoxy resin product, final chlorine mass concentration, final dechlorination rate, actual chlorine transfer load of each extraction stage, actual total chlorine transfer amount and chlorine load at the outlet of the first extraction stage extraction phase; Under the condition of load balancing and non-conforming batch, output the final chlorine mass concentration, the actual chlorine transfer load of each extraction stage, the actual total chlorine transfer amount, and the conclusion that it is not released as a low-chlorine epoxy resin product.

[0015] The present invention has the following beneficial effects: By processing the establishment of the raw material resin solution, confirmation of the extractant's carrying capacity, confirmation of detection capabilities, and collection of basic extraction stage data in the same pre-processing data layer, subsequent extraction design no longer relies on a single empirical ratio, but rather on process-significant data such as the resin solution volume, the initial chlorine concentration of the resin solution, the target chlorine concentration of the product, the effective chlorine carrying capacity of the extractant, and the chlorine concentration corresponding to the limit of quantitation. This approach simultaneously addresses three fundamental questions: how much chlorine is in the material, how much chlorine the extractant can remove at most, and how small a change the detection method can detect. This provides a unified basis for subsequent load allocation, dosage calculation, and acceptance criteria. Compared to existing technologies that involve mixing first and then observing, relying on experience to add extractant, or only detecting chlorine content at the endpoint, this approach quantifies the raw material state, extractant performance, and detection sensitivity upfront. This improves the targeting of process design, reduces blind experimentation and rework, and provides a reliable basis for the calculation and control of each subsequent extraction stage.

[0016] By combining the initial chlorine concentration of the resin feed, the target chlorine concentration of the product, and the resin feed volume, the total amount of chlorine to be removed is first determined. Then, based on the number of extraction stages, the target chlorine load for each stage and the target inlet and outlet chlorine concentrations for each extraction stage are generated. The final chlorine reduction target is broken down into the amount each stage should handle, thus transforming multi-stage extraction from a simple, repetitive process into a tiered process with clearly defined chlorine reduction tasks. Compared to existing technologies that use fixed numbers of stages, fixed ratios, and uniform operating times, this approach emphasizes task decomposition based on the total amount of chlorine to be removed. This ensures that each extraction stage has a clear target outlet concentration and task, improving process controllability and facilitating subsequent verification of whether each stage has achieved its design objectives through actual chlorine load transfer.

[0017] This method calculates the load balance extraction based on the remaining chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of each stage, and compares this with the actual extraction process, forming a unified extractant volume throughout the entire process based on the effective chlorine carrying capacity of the extractant. Its key technical advantage is not simply determining the extractant dosage based on experience, but rather establishing a matching relationship between the amount of chlorine to be removed in each stage and the amount of chlorine the extractant can handle. This simultaneously ensures load balance in each stage and overall process safety, allowing the extractant to meet the total chlorine removal requirements while avoiding significant load deviations in any stage due to varying remaining chlorine to be removed. Compared to existing technologies that add extractant at a fixed volume ratio and then determine compliance through subsequent testing, this method transforms extractant volume design from an experience-based approach to a load-adaptive approach, which improves extractant utilization efficiency, reduces post-treatment pressure, and enhances reproducibility between different batches.

[0018] A multi-stage flow path is established, with the resin phase flowing co-currently and the extract phase flowing counter-currently. This allows fresh extractant to enter the mixing and phase-separation unit corresponding to the final extraction stage, while extract phases from all extraction stages except the first stage are moved to the mixing and phase-separation unit corresponding to the adjacent preceding extraction stage. Counter-current contact enhances the mass transfer driving force, ensuring that the low-chlorine resin phase contacts the fresher extractant in the later stages, while the high-chlorine resin phase contacts the chlorine-enriched extract phase in the earlier stages, thus better conforming to the concentration gradient utilization principle. Compared to existing technologies involving single-tank extraction, multiple liquid changes, or a lack of clear interphase transfer rules, this scheme clearly defines the flow direction of the resin and extract phases, the inlet of the fresh extractant in the final stage, and the outlet of the chlorine-enriched extract phase in the first stage. This makes the multi-stage extraction path clearer, improves extractant utilization efficiency, and reduces the risk of excessive residual chlorine in the final product.

[0019] The effective volume of the resin phase in each extraction stage is defined by the resin feed volume, and the effective volume of the extractant phase in each stage is defined by a unified extractant volume throughout the entire process. Mixing, contact, phase separation, and interphase transfer are performed in each extraction stage. This step not only specifies the contact process but also unifies the relationships between effective volume, continuous contact, static phase separation, and transfer, forming a repeatable extraction unit operation. This avoids phase deviations caused by inconsistent metering between different extraction stages, ensuring that each stage completes the target chlorine load transfer based on the same effective volume, which is beneficial for improving batch stability. Compared with existing technologies that rely on manual experience to control mixing time and phase separation endpoints, this scheme, through the combined design of unified effective volume, mixing contact, and interstage transfer, makes the extraction process more engineered, facilitating scale-up production and subsequent load calculation and determination.

[0020] This method involves detecting and establishing the actual inlet and outlet chlorine concentrations of the resin phase at each extraction stage, calculating the actual transferred chlorine load and total transferred chlorine amount for each extraction stage, and recording the chlorine load of the extract phase. The core value of this approach lies in expanding the extraction results from whether the final product meets standards to a process record of how much chlorine was actually transferred at each stage and how much chlorine was cumulatively carried by the extract phase. This accurately identifies which stage has insufficient extraction, which stage has abnormal load, and whether there is a risk of chlorine carrying over to the extract phase, thus providing a basis for process adjustment and quality traceability. Compared with existing technologies, this approach transforms the process black box into a diagnosable load chain through continuous recording of actual inlet concentration, actual outlet concentration, actual chlorine reduction results, and countercurrent extract phase chlorine load, facilitating batch traceability, anomaly location, and process optimization.

[0021] The batch determination incorporates the detection limit of chlorine concentration, resin volume, uniform extractant volume throughout the process, and effective chlorine capacity of the extractant into batch judgment, forming a system of equilibrium judgment, compliance judgment, monotonic dechlorination judgment, and chlorine-rich extractant phase capacity limit judgment. The permissible deviation of a single-stage load is linked to the detection quantification capability, avoiding misjudging fluctuations within the detection error range as process anomalies. The monotonic dechlorination judgment ensures that the chlorine content of each resin phase does not increase along the process; the capacity limit judgment ensures that the chlorine-rich extractant phase does not exceed the extractant capacity; and the compliance judgment ensures that the final resin phase meets product targets. Compared with existing technologies that rely on single endpoint detection or manual experience for release, this scheme forms a multi-indicator linkage judgment system, making product release more process-based and reducing quality risks caused by detection randomness, extractant saturation, or inter-stage backmixing.

[0022] Using a balanced, qualified batch as a prerequisite for product formation and result output, the chlorine-rich extract phase is discharged under qualified batch conditions. The resin phase outlet liquid of the final extraction stage is then subjected to depressurized solvent removal to obtain a low-chlorine epoxy resin product, generating the final chlorine mass concentration, final dechlorination rate, and extraction load results. The process operation results, product quality results, and process load results are output simultaneously, rather than just yielding a single low-chlorine resin product. Compared to existing technologies that directly desolvate and test the product after extraction, this approach emphasizes judgment, desolvation, and output, while retaining the final chlorine mass concentration, final dechlorination rate, actual chlorine transfer load at each stage, actual total chlorine transfer, and the chlorine load at the outlet of the first-stage extraction stage. This links product formation with process quality records, facilitating industrial-scale quality management, batch release, and subsequent process optimization. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the countercurrent extraction arrangement of the present invention.

[0024] Figure 2 This is a schematic diagram of the raw materials and basic parameters of the present invention.

[0025] Figure 3 This is a schematic diagram showing the chlorine mass concentration of each extraction target in this invention.

[0026] Figure 4 This is a schematic diagram illustrating the determination and product output of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example: A method for solvent extraction to remove chlorine from epoxy resin, comprising: The epoxy resin to be treated is mixed with the main solvent to form a single-phase resin solution. The mass, density, initial and target chlorine mass concentration of the resin solution, extractant loading test, detection quantification and number of units are collected to obtain the resin solution volume, extractant effective chlorine loading concentration and chlorine concentration corresponding to the detection quantification limit. Calculate the total amount of chlorine to be removed based on the initial and target chlorine mass concentrations and the resin liquid volume, determine the number of extraction stages, and generate the target chlorine load for each stage and the target inlet and outlet chlorine mass concentrations of the resin phase for each extraction stage. The load balance extraction was calculated based on the remaining amount of chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of a single stage, and the unified extractant volume throughout the process was formed by combining the effective chlorine carrying capacity of the extractant with the actual extraction volume. Establish a path for the resin phase to flow in the forward direction and the extract phase to flow in the counter-current direction, so that the fresh extractant enters the mixing and phase separation unit corresponding to the final extraction stage, and the extract phase other than the first extraction stage moves into the mixing and phase separation unit corresponding to the adjacent previous extraction stage. Using the resin liquid volume and the unified extractant volume throughout the process as the effective volume of the two phases in each extraction stage, the resin phase outlet liquid and the chlorine-rich extract phase are output. The actual inlet and outlet chlorine mass concentrations of each extraction stage resin phase were detected and established. The actual chlorine transfer load and actual total chlorine transfer amount of each extraction stage were calculated, and the chlorine load of the extraction phase was recorded. Based on the resin liquid volume, the chlorine concentration corresponding to the detection limit, the volume of the extractant throughout the process, and the effective chlorine carrying capacity, the batches are balanced, qualified, monotonically dechlorinated, and the upper limit of carrying capacity are determined to form qualified or unqualified batches. Under qualified batch conditions, the chlorine-rich extraction phase is discharged, and the outlet liquid of the final extraction stage resin phase is desolvated under reduced pressure to obtain a low-chlorine epoxy resin product, thus forming the final chlorine mass concentration, final dechlorination rate, and extraction load results.

[0029] By first mixing the epoxy resin to be treated with the main solvent to form a single-phase resin solution, and then collecting data on the resin solution mass, density, initial chlorine mass concentration, target chlorine mass concentration of the product, extractant loading test data, quantitative detection data, and number of units, the problem of insufficient pre-processing data and reliance on empirically set extraction conditions in existing dechlorination operations is solved. Furthermore, by continuously determining the total amount of chlorine to be removed, the target chlorine load for each stage, the target inlet and outlet chlorine mass concentrations of the resin phase in each extraction stage, the load-balanced extraction ratio, the uniform extractant volume throughout the process, and the actual extraction ratio, the problem of difficulty in accurately matching the extractant dosage to the dechlorination task and the potential uneven distribution of extraction loads at each stage is solved. This scheme also addresses the problem of insufficient utilization of mass transfer driving force in ordinary single-stage extraction or simple repeated extraction by setting the path of co-current resin phase and counter-current extraction phase, allowing fresh extractant to enter from the last stage and the chlorine-rich extraction phase to exit from the first stage. The entire dechlorination process not only focuses on the final chlorine content, but also incorporates the extractant carrying capacity, the actual chlorine transfer load at each stage, monotonic dechlorination, the upper limit of the carrying capacity, and the determination of the qualified product into the process. This transforms the process from an experience-based operation into a calculable, detectable, and traceable closed-loop control method, which is different from the existing technology that judges whether the product is qualified based solely on a fixed number of extractions or endpoint detection.

[0030] Reference Figure 2 The process involves mixing the epoxy resin to be treated with the main solvent to form a single-phase resin solution, collecting data on the resin solution mass, density, initial and target chlorine mass concentrations of the resin solution, extractant loading test, quantitative detection, and number of units to obtain the resin solution volume, extractant effective chlorine loading concentration, and chlorine concentration corresponding to the detection limit. Specifically, this includes: The epoxy resin to be treated is added to the main solvent and stirred to form a single-phase resin solution. The resin solution is then separated into a resin phase and an extract phase after contact with the extractant. Record the resin liquid mass and resin liquid density. Divide the resin liquid mass and resin liquid density by the resin liquid mass, with the resin liquid mass as the dividend and the resin liquid density as the divisor, to obtain the resin liquid volume. The initial chlorine concentration of the resin solution is detected, the target chlorine concentration of the product is set, and the initial chlorine concentration of the resin solution is limited to be higher than the target chlorine concentration of the product, while the target chlorine concentration of the product is limited to be no lower than zero. Extractant carrying capacity test was conducted according to the main solvent, extractant composition and phase separation conditions in the liquid-liquid contact system formed by resin and extractant. The volume and chlorine mass of the chlorine-rich extractant sample were collected after the carrying capacity endpoint was reached, and the volume and chlorine mass of the chlorine-rich extractant sample were limited to be greater than zero. Divide the chlorine mass of the chlorine-rich extractant sample by the volume of the chlorine-rich extractant sample, with the chlorine mass of the chlorine-rich extractant sample being the dividend and the volume of the chlorine-rich extractant sample being the divisor, to obtain the effective chlorine carrying capacity of the extractant. Read the minimum quantitative chlorine mass and detection sampling volume of the chlorine detection method, and limit the minimum quantitative chlorine mass and detection sampling volume of the chlorine detection method to be greater than zero; Divide the minimum quantitative chlorine mass of the chlorine detection method by the detection sampling volume, with the minimum quantitative chlorine mass of the chlorine detection method as the dividend and the detection sampling volume as the divisor, to obtain the chlorine concentration corresponding to the detection limit of quantitation; Read the number of serially connected hybrid phase separation units, use the number of serially connected hybrid phase separation units as the number of extraction stages, establish an extraction stage set from the first extraction stage to the last extraction stage according to the serial connection order, and set a corresponding extraction stage index for each extraction stage.

[0031] By adding the epoxy resin to be treated to the main solvent and stirring it into a single-phase resin solution, the problem of insufficient contact and unstable extraction efficiency when the resin raw material is directly extracted under high viscosity or uneven dispersion is solved. By recording the mass and density of the resin solution and obtaining its volume, the problem of ignoring the volume change of the system when estimating the extraction scale solely based on the mass of the feed material is solved. This scheme also clarifies that the dechlorination process must have a real chlorine reduction task by detecting the initial chlorine mass concentration of the resin solution, setting the target chlorine mass concentration of the product, and limiting the initial concentration to be higher than the target concentration and the target concentration to not be lower than zero, thus avoiding invalid calculations or unreasonable target settings. Its detailed innovation is also reflected in the extractant carrying capacity test, that is, collecting the volume and chlorine mass of a chlorine-rich extractant sample under the main solvent, extractant composition, and phase separation conditions corresponding to the actual liquid-liquid contact system, thereby obtaining the effective chlorine carrying capacity of the extractant. By reading the minimum quantitative chlorine mass and the detection sampling volume of the chlorine detection method and obtaining the chlorine concentration corresponding to the detection limit of quantitation, the problem of ignoring the detection capability boundary in subsequent judgments is solved.

[0032] Reference Figure 3 The calculation of the total amount of chlorine to be removed based on the initial and target chlorine concentrations and the resin feed volume, the determination of the number of extraction stages, and the generation of the target chlorine load for each stage and the target inlet and outlet chlorine concentrations for each extraction stage resin phase specifically include: Read the resin liquid volume, the initial chlorine mass concentration of the resin liquid, and the target chlorine mass concentration of the product. Subtract the target chlorine mass concentration of the product from the initial chlorine mass concentration of the resin liquid to obtain the target chlorine reduction concentration. Multiply the target chlorine reduction concentration by the resin liquid volume to obtain the total amount of chlorine to be removed. The total amount of chlorine to be removed is evenly distributed according to the number of extraction stages to obtain the target chlorine load for each stage. Set the target inlet chlorine mass concentration of the first-stage extraction resin phase as the initial chlorine mass concentration of the resin feed solution. According to the extraction stage sequence from the first extraction stage to the last extraction stage, each extraction stage is marked with a corresponding stage number. The corresponding stage number is multiplied by the single-stage target chlorine load, and the product is divided by the resin liquid volume, with the product being the dividend and the resin liquid volume being the divisor, to obtain the cumulative target chlorine reduction concentration of the corresponding extraction stage. Subtract the cumulative target chlorine reduction concentration of the corresponding extraction stage from the initial chlorine mass concentration of the resin feed solution to obtain the target outlet chlorine mass concentration of the resin phase in the corresponding extraction stage; The decrease in the target outlet chlorine mass concentration of two adjacent extraction stage resin phases is limited to the concentration difference obtained by dividing the single-stage target chlorine load by the resin feed volume, and the target outlet chlorine mass concentration of the previous extraction stage resin phase is used as the target inlet chlorine mass concentration of the next extraction stage resin phase.

[0033] By reading the resin feed volume, initial chlorine concentration, and target chlorine concentration of the product, and accordingly obtaining the target chlorine reduction concentration and total chlorine to be removed, this solves the problem in existing dechlorination processes that only specify endpoint indicators without converting them into actual chlorine removal tasks. Furthermore, by evenly distributing the total chlorine to be removed according to the number of extraction stages, a single-stage target chlorine load is obtained, ensuring that each extraction stage is not merely a formal repetition but has a clearly defined load task. By setting the target inlet chlorine concentration of the resin phase in the first extraction stage as the initial chlorine concentration of the resin feed, and generating the cumulative target chlorine reduction concentration and the target outlet chlorine concentration for each stage according to the extraction stage sequence, the problem of lacking continuous continuity of target concentrations in multi-stage extraction is solved. Finally, by using the target outlet chlorine concentration of the resin phase in the previous extraction stage as the target inlet chlorine concentration of the resin phase in the next extraction stage, a progressively decreasing target concentration chain is established.

[0034] Reference Figure 3 The calculation of load-balanced extraction based on the remaining chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of a single stage, compared with the total volume of extractant formed by combining the effective chlorine carrying capacity of the extractant and the actual extraction, specifically includes: For each extraction stage, calculate the target chlorine concentration to be reduced at the current extraction stage resin inlet based on the current target inlet chlorine concentration and the target chlorine concentration of the product. Multiply the current chlorine concentration to be reduced at the target inlet of the extraction-stage resin phase by the resin liquid volume to obtain the remaining amount of chlorine to be removed at the target inlet of the current extraction-stage resin phase. Divide the single-stage target chlorine load by the remaining amount of chlorine to be removed at the target inlet of the current extraction stage resin phase, with the single-stage target chlorine load as the dividend and the remaining amount of chlorine to be removed at the target inlet of the current extraction stage resin phase as the divisor, to obtain the current extraction stage load balanced extraction ratio; Divide the total amount of chlorine to be removed by the effective chlorine carrying capacity of the extractant, with the total amount of chlorine to be removed being the dividend and the effective chlorine carrying capacity of the extractant being the divisor, to obtain the total carrying capacity of the extractant volume for the entire process. The load equalization extraction ratio of each extraction stage is multiplied by the resin feed volume to obtain the load equalization required volume for the corresponding extraction stage. The maximum value between the total capacity limit of the extractant volume and the volume required for load balancing of all extraction stages is taken to obtain the uniform extractant volume for the entire process. Divide the volume of the uniform extractant throughout the process by the volume of the resin solution, with the volume of the uniform extractant throughout the process being the dividend and the volume of the resin solution being the divisor, to obtain the actual extraction comparison of the entire process. Multiply the volume of the extractant throughout the entire process by the effective chlorine carrying capacity of the extractant, and limit the product to be no less than the total amount of chlorine to be removed.

[0035] By calculating the target chlorine concentration to be reduced at the resin inlet for each extraction stage and further obtaining the remaining chlorine to be removed at the target inlet of the resin phase in the current extraction stage, the problem of the extractant dosage at each stage not being adapted to the remaining chlorine removal task of that stage in the existing technology is solved. Subsequently, by determining the relationship between the target chlorine load of a single stage and the remaining chlorine to be removed at the target inlet, the current extraction stage load balance extraction is compared, ensuring that the extraction task of each stage is not just evenly distributed, but matched with the inlet state of that stage. The total chlorine to be removed and the effective chlorine carrying capacity of the extractant are used to obtain the total process carrying capacity limiting extractant volume, and this is compared with the load balance requirement of all extraction stages. The larger result is taken as the uniform extractant volume for the entire process, solving the problem that simply calculating the load balance may ignore the total carrying capacity of the extractant, and simply calculating the total carrying capacity may ignore the contact requirements of a single stage.

[0036] Reference Figure 1 The establishment of a resin phase co-current and extract phase counter-current path, allowing fresh extractant to enter the mixing and phase separation unit corresponding to the final extraction stage, and allowing the extract phase (excluding the first extraction stage) to move into the mixing and phase separation unit corresponding to the adjacent preceding extraction stage, specifically includes: The resin feed is fed into the mixing and phase separation unit corresponding to the first extraction stage, and flows through the mixing and phase separation units corresponding to each extraction stage in series order. After the resin feed solution completes the mixing and phase separation in the final extraction stage, the resin phase outlet feed solution of the final extraction stage is output from the corresponding mixing and phase separation unit of the final extraction stage. A blank chlorine load deduction was performed on the fresh extractant to form a fresh extractant stream after blank chlorine load deduction; The fresh extractant stream after blank chlorine load deduction is sent to the corresponding mixing and phase separation unit of the final extraction stage and serves as the inlet stream of the extraction phase of the final extraction stage. For each extraction stage except the first extraction stage, the extract phase output from the mixing and phase separation unit corresponding to the current extraction stage is sent to the mixing and phase separation unit corresponding to the adjacent previous extraction stage and used as the inlet stream of the extract phase of the adjacent previous extraction stage. The extraction phase output from the mixing and phase separation unit corresponding to the first extraction stage is used as the chlorine-rich extraction phase.

[0037] By feeding the resin feed solution into the mixing and phase separation unit corresponding to the first extraction stage, and then sequentially flowing through the mixing and phase separation units corresponding to each extraction stage in series, the problems of unclear resin phase path and chaotic material transfer between stages in multi-stage processing are solved. By outputting the resin phase outlet feed solution after mixing and phase separation in the final extraction stage, the outlet position of the low-chlorine resin phase is clearly defined. A beneficial detail of this scheme is that the fresh extractant is subjected to blank chlorine load deduction before being fed into the final extraction stage, serving as the inlet stream for the final extraction stage's extractant phase. This solves the problem of background chlorine potentially being introduced by the extractant itself, affecting load recording and load assessment. Furthermore, by feeding the extractant phase from each stage other than the first extraction stage into the adjacent preceding extraction stage, the extractant phase moves countercurrently from the final stage to the first stage, and finally, the extractant phase output from the first stage is used as the chlorine-rich extractant phase.

[0038] Reference Figure 1 The process involves using the resin feed volume and the unified extractant volume throughout the entire process as the effective volumes of the two phases in each extraction stage, performing mixing, contact, phase separation, and transfer, and outputting the final extraction stage resin phase outlet liquid and chlorine-rich extract phase. Specifically, this includes: For each extraction stage, the resin phase entering the corresponding mixing and phase separation unit of the current extraction stage is metered, and the effective volume of the resin phase fed in is recorded as the effective volume of the resin phase in the current extraction stage. The effective volume of the resin phase in the current extraction stage is taken as the volume of the resin liquid. The extraction phase entering the mixing and phase separation unit corresponding to the current extraction stage is metered, and the effective volume of the extracted phase is recorded as the effective volume of the extraction phase in the current extraction stage. The effective volume of the extraction phase in the current extraction stage is taken as the volume of the extractant throughout the entire process, so that the resin liquid and the extractant form a liquid-liquid contact system in the mixing and phase separation unit corresponding to the current extraction stage. Read the mixed circulation flow rate and set the fixed number of mixed liquid changes to three; Add the current effective volume of the resin phase in the extraction stage to the current effective volume of the extraction phase in the extraction stage to obtain the total effective volume of single-stage contact in the current extraction stage. Multiply the total effective volume of single-stage contact in the current extraction stage by the fixed number of mixing and liquid exchange cycles, and then divide the product by the mixing circulation flow rate, with the product being the dividend and the mixing circulation flow rate being the divisor, to obtain the uniform mixing contact time. The resin feed and extractant are kept in continuous contact within a uniform mixing contact time, and the single-stage target chlorine load is used as the liquid-liquid contact design quantity for the current extraction stage corresponding to the mixing and phase separation unit. Multiply the effective volume of the extractant phase in the current extraction stage by the effective chlorine load concentration of the extractant to obtain the extractant phase load of the mixed phase separation unit corresponding to the current extraction stage, and verify that the extractant phase load of the mixed phase separation unit corresponding to the current extraction stage is not lower than the single-stage target chlorine load. After the mixing contact is complete, stop mixing and let stand until the resin phase and the extraction phase form a separable interface; The resin phase of each extraction stage, except the final extraction stage, is fed into the corresponding mixing and phase separation unit of the next adjacent extraction stage. The extract phase of each extraction stage except the first extraction stage is fed into the mixing and phase separation unit corresponding to the adjacent previous extraction stage. The final extraction stage resin phase outlet liquid is output from the mixing and phase separation unit corresponding to the final extraction stage, and the chlorine-rich extraction phase is output from the mixing and phase separation unit corresponding to the first extraction stage.

[0039] By separately metering the resin phase and extractant phase entering each current extraction stage's corresponding mixing and phase-separation unit, and taking the effective volume of the resin phase as the resin feed volume and the effective volume of the extractant phase as the unified extractant volume throughout the entire process, the problems of inconsistent feed volumes at each stage leading to deviations in the extractant phase and inaccurate load calculations in existing operations are solved. By reading the mixing circulation flow rate, setting a fixed number of mixing and liquid exchange cycles, and obtaining a unified mixing contact time based on the total effective volume of single-stage contact in the current extraction stage, the problem of inconsistent contact levels caused by relying solely on manual experience to control mixing time for different batches or levels is solved. Furthermore, by using the single-stage target chlorine load as the liquid-liquid contact design quantity and verifying that the current extraction stage's extractant phase load is not lower than the single-stage target chlorine load, the problem of potential insufficient extractant load in single-stage contact is solved. After mixing is completed, mixing is stopped and allowed to stand until a separable interface is formed before the resin phase is transferred co-currently and the extractant phase counter-currently, reducing entrainment and inter-stage cross-contamination caused by insufficient phase separation.

[0040] Reference Figure 4 The process of detecting and establishing the actual inlet and outlet chlorine mass concentrations of each extraction stage resin phase, calculating the actual transferred chlorine load and the actual total transferred chlorine amount of each extraction stage, and recording the chlorine load of the extraction phase specifically includes: Samples were taken from the resin phase after each extraction stage phase separation, and the actual chlorine mass concentration at the outlet of the corresponding extraction stage resin phase was detected. The actual chlorine mass concentration at the outlet of the corresponding extraction stage resin phase was then limited to not less than zero. Based on the initial chlorine mass concentration of the resin feed and the actual chlorine mass concentration at the outlet of each extraction stage resin phase, a sequence of actual chlorine mass concentrations of the resin phase from the actual inlet of the first extraction stage resin phase to the actual outlet of the last extraction stage resin phase is established. The initial chlorine mass concentration of the resin feed is taken as the actual inlet chlorine mass concentration of the first extraction stage resin phase, and the actual outlet chlorine mass concentration of the adjacent preceding extraction stage resin phase is taken as the actual inlet chlorine mass concentration of the subsequent extraction stage resin phase. For each extraction stage, the actual chlorine concentration at the inlet of the resin phase of the current extraction stage is subtracted from the actual chlorine concentration at the outlet of the resin phase of the current extraction stage to obtain the actual chlorine reduction concentration of the current extraction stage. Multiply the actual chlorine reduction concentration in the current extraction stage by the resin liquid volume to obtain the current chlorine transfer candidate amount in the extraction stage; When the current chlorine transfer candidate quantity in the extraction stage is not less than zero, the current chlorine transfer candidate quantity in the extraction stage is recorded as the current actual chlorine transfer load in the extraction stage; when the current chlorine transfer candidate quantity in the extraction stage is less than zero, the current actual chlorine transfer load in the extraction stage is recorded as zero. For the fresh extractant stream after blank chlorine load deduction, the chlorine load at the inlet of the final extraction stage is recorded as zero; According to the order in which the extractant phase is countercurrently transferred from the final extraction stage to the first extraction stage, for each extraction stage from the final extraction stage to the second extraction stage, the inlet chlorine load of the extractant phase of the current extraction stage is added to the actual transferred chlorine load of the extractant phase of the current extraction stage to obtain the outlet chlorine load of the extractant phase of the current extraction stage. The chlorine load at the outlet of the extraction phase of each extraction stage from the last extraction stage to the second extraction stage is recorded as the chlorine load at the inlet of the extraction phase of the adjacent previous extraction stage. After the transfer of chlorine load at the inlet of the extraction phase from the second extraction stage to the first extraction stage is completed, the chlorine load at the inlet of the extraction phase of the first extraction stage is added to the actual transferred chlorine load of the extraction phase of the first extraction stage to obtain the chlorine load at the outlet of the extraction phase of the first extraction stage.

[0041] By sampling the resin phase after phase separation at each extraction stage and detecting the actual outlet chlorine concentration of the corresponding extraction stage resin phase, the problem of existing technologies that only detect the final product and cannot determine the effectiveness of intermediate extraction stages is solved. By using the initial chlorine concentration of the resin feed as the actual inlet chlorine concentration of the first-stage resin phase and the actual outlet chlorine concentration of the resin phase of the adjacent preceding extraction stage as the actual inlet chlorine concentration of the subsequent extraction stage resin phase, an actual concentration sequence from the actual inlet of the first stage to the actual outlet of the final stage is established, solving the problem of lacking continuous concentration tracking in multi-stage processes. The actual chlorine reduction concentration of the current extraction stage is obtained through the actual inlet and actual outlet concentrations, and the chlorine transfer candidate quantity is further obtained; when the candidate quantity is below zero, the actual transferred chlorine load is recorded as zero, avoiding unreasonable negative values ​​in the load record due to detection fluctuations or abnormal rebounds.

[0042] Reference Figure 4 The process involves determining whether a batch is qualified or unqualified based on the resin liquid volume, the chlorine concentration corresponding to the detection limit, the volume of the extractant throughout the process, and the effective chlorine carrying capacity, including equalization, compliance, monotonic dechlorination, and upper limit determination, resulting in a qualified or unqualified batch. Specifically, this includes: Multiply the resin liquid volume by the chlorine concentration corresponding to the detection limit to obtain the permissible deviation for a single load. For each extraction stage, an equilibrium determination is made regarding the actual transferred chlorine load. First, the difference between the current actual transferred chlorine load of the extraction stage and the target chlorine load of the single stage is calculated. Then, the absolute value of the difference is transformed to form the absolute value of the current extraction stage load difference. Finally, it is checked that the absolute value of the current extraction stage load difference is not greater than the allowable deviation of the single stage load. The actual chlorine mass concentration at the outlet of the final extraction stage resin phase is judged to meet the standard, and it is verified that the actual chlorine mass concentration at the outlet of the final extraction stage resin phase is not higher than the target chlorine mass concentration of the product. The actual chlorine transfer load of each extraction stage is added together to obtain the actual total chlorine transfer amount; Multiply the volume of the extractant throughout the entire process by the effective chlorine carrying capacity of the extractant to obtain the upper limit of the chlorine-rich extract phase carrying capacity. Then, determine the upper limit of the chlorine-rich extract phase carrying capacity and verify that the chlorine load at the outlet of the first-stage extract phase does not exceed the upper limit of the chlorine-rich extract phase carrying capacity. For each extraction stage, a monotonic dechlorination determination is performed on the actual inlet chlorine concentration and the actual outlet chlorine concentration of the resin phase. The actual inlet chlorine concentration of the current extraction stage resin phase is verified to be no lower than the actual outlet chlorine concentration of the current extraction stage resin phase. When the actual chlorine transfer load of each extraction stage passes the balance judgment, the monotonic dechlorination judgment of each extraction stage passes the judgment, the actual outlet chlorine mass concentration of the resin phase of the final extraction stage passes the standard judgment, and the outlet chlorine load of the extraction phase of the first extraction stage passes the upper limit judgment of the chlorine-rich extraction phase, it is recorded as a load balance qualified batch. If any of the following criteria are not met: balance determination, monotonous dechlorination determination, compliance determination, or upper limit determination of chlorine-rich extract phase load, it shall be recorded as a batch that fails to meet the load balance criteria and shall not be recorded as a release conclusion for low-chlorine epoxy resin products.

[0043] By determining the permissible deviation of the single-stage load by comparing the resin feed volume with the chlorine concentration corresponding to the detection limit of quantitation, this addresses the problem in existing technologies where the capability of the detection method is not included in the process judgment, and small fluctuations within the detection error range are easily misjudged as process anomalies. By balancing the actual transferred chlorine load for each extraction stage, the problem of deviations from the target extraction load at each stage being difficult to detect is solved. By determining the compliance of the actual outlet chlorine mass concentration of the resin phase in the final extraction stage, the issue of whether the chlorine content of the final product meets the product target is resolved. By unifying the extractant volume and effective chlorine carrying capacity throughout the process to obtain the upper limit of the chlorine-rich extraction phase carrying capacity, and verifying that the chlorine load at the outlet of the first-stage extraction stage does not exceed this upper limit, the problem of the chlorine-rich extraction phase potentially exceeding its carrying capacity and affecting the stability of subsequent extractions is solved. Simultaneously, by using a monotonic dechlorination judgment to verify that the actual inlet chlorine mass concentration of each resin phase is not lower than the actual outlet chlorine mass concentration, the problem of chlorine content reversal caused by local backmixing, detection anomalies, or process loss of control is avoided.

[0044] Reference Figure 4 The process involves discharging the chlorine-rich extract phase under qualified batch conditions, desolvating the final extraction stage resin phase outlet liquid under reduced pressure to obtain a low-chlorine epoxy resin product, and generating final chlorine mass concentration, final dechlorination rate, and extraction load results, specifically including: Under the condition of load balance and qualified batch, the extract phase output from the mixing and phase separation unit corresponding to the first extraction stage is discharged as the chlorine-rich extract phase. Under the condition of a load-balanced qualified batch, the outlet liquid of the final extraction stage resin phase is retained as the low-chlorine resin liquid; Under load-balanced qualified batch conditions, the low-chlorine resin solution is subjected to desolventizing under reduced pressure to remove the main solvent and residual extractant, thereby obtaining the low-chlorine epoxy resin product. The actual outlet chlorine mass concentration of the final extraction stage resin phase is taken as the final chlorine mass concentration. Under the condition of load balance and qualified batch, the initial chlorine mass concentration of the resin solution is subtracted from the final chlorine mass concentration to obtain the final chlorine reduction concentration. The final chlorine reduction concentration is then divided by the initial chlorine mass concentration of the resin solution, with the final chlorine reduction concentration as the dividend and the initial chlorine mass concentration of the resin solution as the divisor, to obtain the final chlorine removal rate. Under the condition of load balance and qualified batch, the output is low-chlorine epoxy resin product, final chlorine mass concentration, final dechlorination rate, actual chlorine transfer load of each extraction stage, actual total chlorine transfer amount and chlorine load at the outlet of the first extraction stage extraction phase; Under the condition of load balancing and non-conforming batch, output the final chlorine mass concentration, the actual chlorine transfer load of each extraction stage, the actual total chlorine transfer amount, and the conclusion that it is not released as a low-chlorine epoxy resin product.

[0045] By discharging the chlorine-rich extract phase from the first-stage extraction stage corresponding to the mixed-phase separation unit under balanced load and qualified batch conditions, and retaining the resin phase outlet liquid from the final extraction stage as the low-chlorine resin feed liquid, the problem of unqualified materials being directly fed into post-processing without process judgment was solved, which could lead to the continued processing of unqualified materials. By subjecting the low-chlorine resin feed liquid to reduced pressure desolventizing under qualified batch conditions to remove the main solvent and residual extractant, low-chlorine epoxy resin products were obtained, solving the problem that the resin feed liquid still contained solvent and extractant after extraction and could not be used directly as a product. By using the actual outlet chlorine mass concentration of the final extraction stage resin phase as the final chlorine mass concentration, and obtaining the final dechlorination concentration and final dechlorination rate under qualified batch conditions, the problem of the lack of a correlation between the final product quality results and the process dechlorination effect was solved.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for solvent extraction and chlorine removal from epoxy resin, characterized in that, include: The epoxy resin to be treated is mixed with the main solvent to form a single-phase resin solution. The mass, density, initial and target chlorine mass concentration of the resin solution, extractant loading test, detection quantification and number of units are collected to obtain the resin solution volume, extractant effective chlorine loading concentration and chlorine concentration corresponding to the detection quantification limit. Calculate the total amount of chlorine to be removed based on the initial and target chlorine mass concentrations and the resin liquid volume, determine the number of extraction stages, and generate the target chlorine load for each stage and the target inlet and outlet chlorine mass concentrations of the resin phase for each extraction stage. The load balance extraction was calculated based on the remaining amount of chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of a single stage, and the unified extractant volume throughout the process was formed by combining the effective chlorine carrying capacity of the extractant with the actual extraction volume. Establish a path for the resin phase to flow in the forward direction and the extract phase to flow in the counter-current direction, so that the fresh extractant enters the mixing and phase separation unit corresponding to the final extraction stage, and the extract phase other than the first extraction stage moves into the mixing and phase separation unit corresponding to the adjacent previous extraction stage. Using the resin liquid volume and the unified extractant volume throughout the process as the effective volume of the two phases in each extraction stage, the resin phase outlet liquid and the chlorine-rich extract phase are output. The actual inlet and outlet chlorine mass concentrations of each extraction stage resin phase were detected and established. The actual chlorine transfer load and actual total chlorine transfer amount of each extraction stage were calculated, and the chlorine load of the extraction phase was recorded. Based on the resin liquid volume, the chlorine concentration corresponding to the detection limit, the volume of the extractant throughout the process, and the effective chlorine carrying capacity, the batches are balanced, qualified, monotonically dechlorinated, and the upper limit of carrying capacity are determined to form qualified or unqualified batches. Under qualified batch conditions, the chlorine-rich extraction phase is discharged, and the outlet liquid of the final extraction stage resin phase is desolvated under reduced pressure to obtain a low-chlorine epoxy resin product, thus forming the final chlorine mass concentration, final dechlorination rate, and extraction load results.

2. The method for solvent extraction and dechlorination of epoxy resin according to claim 1, characterized in that, The process involves mixing the epoxy resin to be treated with the main solvent to form a single-phase resin solution. The resin solution mass, density, initial and target chlorine mass concentrations, extractant loading tests, quantitative detection, and number of units are collected to obtain the resin solution volume, extractant effective chlorine loading concentration, and chlorine concentration corresponding to the detection limit. Specifically, this includes: The epoxy resin to be treated is added to the main solvent and stirred to form a single-phase resin solution. The resin solution is then separated into a resin phase and an extract phase after contact with the extractant. Record the resin liquid mass and resin liquid density. Divide the resin liquid mass and resin liquid density by the resin liquid mass, with the resin liquid mass as the dividend and the resin liquid density as the divisor, to obtain the resin liquid volume. The initial chlorine concentration of the resin solution is detected, the target chlorine concentration of the product is set, and the initial chlorine concentration of the resin solution is limited to be higher than the target chlorine concentration of the product, while the target chlorine concentration of the product is limited to be no lower than zero. Extractant carrying capacity test was conducted according to the main solvent, extractant composition and phase separation conditions in the liquid-liquid contact system formed by resin and extractant. The volume and chlorine mass of the chlorine-rich extractant sample were collected after the carrying capacity endpoint was reached, and the volume and chlorine mass of the chlorine-rich extractant sample were limited to be greater than zero. Divide the chlorine mass of the chlorine-rich extractant sample by the volume of the chlorine-rich extractant sample, with the chlorine mass of the chlorine-rich extractant sample being the dividend and the volume of the chlorine-rich extractant sample being the divisor, to obtain the effective chlorine carrying capacity of the extractant. Read the minimum quantitative chlorine mass and detection sampling volume of the chlorine detection method, and limit the minimum quantitative chlorine mass and detection sampling volume of the chlorine detection method to be greater than zero; Divide the minimum quantitative chlorine mass of the chlorine detection method by the detection sampling volume, with the minimum quantitative chlorine mass of the chlorine detection method as the dividend and the detection sampling volume as the divisor, to obtain the chlorine concentration corresponding to the detection limit of quantitation; Read the number of serially connected hybrid phase separation units, use the number of serially connected hybrid phase separation units as the number of extraction stages, establish an extraction stage set from the first extraction stage to the last extraction stage according to the serial connection order, and set a corresponding extraction stage index for each extraction stage.

3. The method for solvent extraction and dechlorination of epoxy resin according to claim 2, characterized in that, The calculation of the total amount of chlorine to be removed based on the initial and target chlorine mass concentrations and the resin feed volume, the determination of the number of extraction stages, and the generation of the target chlorine load for each stage and the target inlet and outlet chlorine mass concentrations for each extraction stage resin phase specifically include: Read the resin liquid volume, the initial chlorine mass concentration of the resin liquid, and the target chlorine mass concentration of the product. Subtract the target chlorine mass concentration of the product from the initial chlorine mass concentration of the resin liquid to obtain the target chlorine reduction concentration. Multiply the target chlorine reduction concentration by the resin liquid volume to obtain the total amount of chlorine to be removed. The total amount of chlorine to be removed is evenly distributed according to the number of extraction stages to obtain the target chlorine load for each stage. Set the target inlet chlorine mass concentration of the first-stage extraction resin phase as the initial chlorine mass concentration of the resin feed solution. According to the extraction stage sequence from the first extraction stage to the last extraction stage, each extraction stage is marked with a corresponding stage number. The corresponding stage number is multiplied by the single-stage target chlorine load, and the product is divided by the resin liquid volume, with the product being the dividend and the resin liquid volume being the divisor, to obtain the cumulative target chlorine reduction concentration of the corresponding extraction stage. Subtract the cumulative target chlorine reduction concentration of the corresponding extraction stage from the initial chlorine mass concentration of the resin feed solution to obtain the target outlet chlorine mass concentration of the resin phase in the corresponding extraction stage; The decrease in the target outlet chlorine mass concentration of two adjacent extraction stage resin phases is limited to the concentration difference obtained by dividing the single-stage target chlorine load by the resin feed volume, and the target outlet chlorine mass concentration of the previous extraction stage resin phase is used as the target inlet chlorine mass concentration of the next extraction stage resin phase.

4. The solvent extraction method for dechlorination of epoxy resin according to claim 3, characterized in that, The comparison between the load-balanced extraction calculated based on the remaining chlorine to be removed at the target inlet of each extraction stage resin phase and the target chlorine load of a single stage, and the comparison between the extractant volume calculated using the effective chlorine carrying capacity of the extractant to form a uniform extractant volume throughout the process and the actual extraction, specifically includes: For each extraction stage, calculate the target chlorine concentration to be reduced at the current extraction stage resin inlet based on the current target inlet chlorine concentration and the target chlorine concentration of the product. Multiply the current chlorine concentration to be reduced at the target inlet of the extraction-stage resin phase by the resin liquid volume to obtain the remaining amount of chlorine to be removed at the target inlet of the current extraction-stage resin phase. Divide the single-stage target chlorine load by the remaining amount of chlorine to be removed at the target inlet of the current extraction stage resin phase, with the single-stage target chlorine load as the dividend and the remaining amount of chlorine to be removed at the target inlet of the current extraction stage resin phase as the divisor, to obtain the current extraction stage load balanced extraction ratio; Divide the total amount of chlorine to be removed by the effective chlorine carrying capacity of the extractant, with the total amount of chlorine to be removed being the dividend and the effective chlorine carrying capacity of the extractant being the divisor, to obtain the total carrying capacity of the extractant volume for the entire process. The load equalization extraction ratio of each extraction stage is multiplied by the resin feed volume to obtain the load equalization required volume for the corresponding extraction stage. The maximum value between the total capacity limit of the extractant volume and the volume required for load balancing of all extraction stages is taken to obtain the uniform extractant volume for the entire process. Divide the volume of the uniform extractant throughout the process by the volume of the resin solution, with the volume of the uniform extractant throughout the process being the dividend and the volume of the resin solution being the divisor, to obtain the actual extraction comparison of the entire process. Multiply the volume of the extractant throughout the entire process by the effective chlorine carrying capacity of the extractant, and limit the product to be no less than the total amount of chlorine to be removed.

5. The method for solvent extraction and dechlorination of epoxy resin according to claim 4, characterized in that, The establishment of a co-current resin phase and counter-current extractive phase path, allowing fresh extractant to enter the mixing and phase separation unit corresponding to the final extraction stage, and allowing the extractive phase (excluding the first extraction stage) to move into the mixing and phase separation unit corresponding to the adjacent preceding extraction stage, specifically includes: The resin feed is fed into the mixing and phase separation unit corresponding to the first extraction stage, and flows through the mixing and phase separation units corresponding to each extraction stage in series order. After the resin feed solution completes the mixing and phase separation in the final extraction stage, the resin phase outlet feed solution of the final extraction stage is output from the corresponding mixing and phase separation unit of the final extraction stage. A blank chlorine load deduction was performed on the fresh extractant to form a fresh extractant stream after blank chlorine load deduction; The fresh extractant stream after blank chlorine load deduction is sent to the corresponding mixing and phase separation unit of the final extraction stage and serves as the inlet stream of the extraction phase of the final extraction stage. For each extraction stage except the first extraction stage, the extract phase output from the mixing and phase separation unit corresponding to the current extraction stage is sent to the mixing and phase separation unit corresponding to the adjacent previous extraction stage and used as the inlet stream of the extract phase of the adjacent previous extraction stage. The extraction phase output from the mixing and phase separation unit corresponding to the first extraction stage is used as the chlorine-rich extraction phase.

6. The method for solvent extraction and dechlorination of epoxy resin according to claim 5, characterized in that, The process uses the resin feed volume and the unified extractant volume throughout the entire process as the effective volume of the two phases in each extraction stage, performing mixing, contact, phase separation, and transfer to output the final extraction stage resin phase outlet liquid and chlorine-rich extract phase. Specifically, this includes: For each extraction stage, the resin phase entering the corresponding mixing and phase separation unit of the current extraction stage is metered, and the effective volume of the resin phase fed in is recorded as the effective volume of the resin phase in the current extraction stage. The effective volume of the resin phase in the current extraction stage is taken as the volume of the resin liquid. The extraction phase entering the mixing and phase separation unit corresponding to the current extraction stage is metered, and the effective volume of the extracted phase is recorded as the effective volume of the extraction phase in the current extraction stage. The effective volume of the extraction phase in the current extraction stage is taken as the volume of the extractant throughout the entire process, so that the resin liquid and the extractant form a liquid-liquid contact system in the mixing and phase separation unit corresponding to the current extraction stage. Read the mixed circulation flow rate and set the fixed number of mixed liquid changes to three; Add the current effective volume of the resin phase in the extraction stage to the current effective volume of the extraction phase in the extraction stage to obtain the total effective volume of single-stage contact in the current extraction stage. Multiply the total effective volume of single-stage contact in the current extraction stage by the fixed number of mixing and liquid exchange cycles, and then divide the product by the mixing circulation flow rate, with the product being the dividend and the mixing circulation flow rate being the divisor, to obtain the uniform mixing contact time. The resin feed and extractant are kept in continuous contact within a uniform mixing contact time, and the single-stage target chlorine load is used as the liquid-liquid contact design quantity for the current extraction stage corresponding to the mixing and phase separation unit. Multiply the effective volume of the extractant phase in the current extraction stage by the effective chlorine load concentration of the extractant to obtain the extractant phase load of the mixed phase separation unit corresponding to the current extraction stage, and verify that the extractant phase load of the mixed phase separation unit corresponding to the current extraction stage is not lower than the single-stage target chlorine load. After the mixing contact is complete, stop mixing and let stand until the resin phase and the extraction phase form a separable interface; The resin phase of each extraction stage, except the final extraction stage, is fed into the corresponding mixing and phase separation unit of the next adjacent extraction stage. The extract phase of each extraction stage except the first extraction stage is fed into the mixing and phase separation unit corresponding to the adjacent previous extraction stage. The final extraction stage resin phase outlet liquid is output from the mixing and phase separation unit corresponding to the final extraction stage, and the chlorine-rich extraction phase is output from the mixing and phase separation unit corresponding to the first extraction stage.

7. The solvent extraction method for dechlorination of epoxy resin according to claim 6, characterized in that, The process of detecting and establishing the actual inlet and outlet chlorine mass concentrations of each extraction stage resin phase, calculating the actual transferred chlorine load and the actual total transferred chlorine amount of each extraction stage, and recording the chlorine load of the extraction phase specifically includes: Samples were taken from the resin phase after each extraction stage phase separation, and the actual chlorine mass concentration at the outlet of the corresponding extraction stage resin phase was detected. The actual chlorine mass concentration at the outlet of the corresponding extraction stage resin phase was then limited to not less than zero. Based on the initial chlorine mass concentration of the resin feed and the actual chlorine mass concentration at the outlet of each extraction stage resin phase, a sequence of actual chlorine mass concentrations of the resin phase from the actual inlet of the first extraction stage resin phase to the actual outlet of the last extraction stage resin phase is established. The initial chlorine mass concentration of the resin feed is taken as the actual inlet chlorine mass concentration of the first extraction stage resin phase, and the actual outlet chlorine mass concentration of the adjacent preceding extraction stage resin phase is taken as the actual inlet chlorine mass concentration of the subsequent extraction stage resin phase. For each extraction stage, the actual chlorine concentration at the inlet of the resin phase of the current extraction stage is subtracted from the actual chlorine concentration at the outlet of the resin phase of the current extraction stage to obtain the actual chlorine reduction concentration of the current extraction stage. Multiply the actual chlorine reduction concentration in the current extraction stage by the resin liquid volume to obtain the current chlorine transfer candidate amount in the extraction stage; When the current chlorine transfer candidate quantity in the extraction stage is not less than zero, the current chlorine transfer candidate quantity in the extraction stage is recorded as the current actual chlorine transfer load in the extraction stage; when the current chlorine transfer candidate quantity in the extraction stage is less than zero, the current actual chlorine transfer load in the extraction stage is recorded as zero. For the fresh extractant stream after blank chlorine load deduction, the chlorine load at the inlet of the final extraction stage is recorded as zero; According to the order in which the extractant phase is countercurrently transferred from the final extraction stage to the first extraction stage, for each extraction stage from the final extraction stage to the second extraction stage, the inlet chlorine load of the extractant phase of the current extraction stage is added to the actual transferred chlorine load of the extractant phase of the current extraction stage to obtain the outlet chlorine load of the extractant phase of the current extraction stage. The chlorine load at the outlet of the extraction phase of each extraction stage from the last extraction stage to the second extraction stage is recorded as the chlorine load at the inlet of the extraction phase of the adjacent previous extraction stage. After the transfer of chlorine load at the inlet of the extraction phase from the second extraction stage to the first extraction stage is completed, the chlorine load at the inlet of the extraction phase of the first extraction stage is added to the actual transferred chlorine load of the extraction phase of the first extraction stage to obtain the chlorine load at the outlet of the extraction phase of the first extraction stage.

8. The solvent extraction method for dechlorination of epoxy resin according to claim 7, characterized in that, The process involves determining whether a batch is qualified or unqualified based on the resin liquid volume, the chlorine concentration corresponding to the detection limit, the volume of the extractant throughout the process, and the effective chlorine carrying capacity, including equalization, compliance, monotonic dechlorination, and upper limit determination. Multiply the resin liquid volume by the chlorine concentration corresponding to the detection limit to obtain the permissible deviation for a single load. For each extraction stage, an equilibrium determination is made regarding the actual transferred chlorine load. First, the difference between the current actual transferred chlorine load of the extraction stage and the target chlorine load of the single stage is calculated. Then, the absolute value of the difference is transformed to form the absolute value of the current extraction stage load difference. Finally, it is checked that the absolute value of the current extraction stage load difference is not greater than the allowable deviation of the single stage load. The actual chlorine mass concentration at the outlet of the final extraction stage resin phase is judged to meet the standard, and it is verified that the actual chlorine mass concentration at the outlet of the final extraction stage resin phase is not higher than the target chlorine mass concentration of the product. The actual chlorine transfer load of each extraction stage is added together to obtain the actual total chlorine transfer amount; Multiply the volume of the extractant throughout the entire process by the effective chlorine carrying capacity of the extractant to obtain the upper limit of the chlorine-rich extract phase carrying capacity. Then, determine the upper limit of the chlorine-rich extract phase carrying capacity and verify that the chlorine load at the outlet of the first-stage extract phase does not exceed the upper limit of the chlorine-rich extract phase carrying capacity. For each extraction stage, a monotonic dechlorination determination is performed on the actual inlet chlorine concentration and the actual outlet chlorine concentration of the resin phase. The actual inlet chlorine concentration of the current extraction stage resin phase is verified to be no lower than the actual outlet chlorine concentration of the current extraction stage resin phase. When the actual chlorine transfer load of each extraction stage passes the balance judgment, the monotonic dechlorination judgment of each extraction stage passes the judgment, the actual outlet chlorine mass concentration of the resin phase of the final extraction stage passes the standard judgment, and the outlet chlorine load of the extraction phase of the first extraction stage passes the upper limit judgment of the chlorine-rich extraction phase, it is recorded as a load balance qualified batch. If any of the following criteria are not met: balance determination, monotonous dechlorination determination, compliance determination, or upper limit determination of chlorine-rich extract phase load, it shall be recorded as a batch that fails to meet the load balance criteria and shall not be recorded as a release conclusion for low-chlorine epoxy resin products.

9. The solvent extraction method for dechlorination of epoxy resin according to claim 8, characterized in that, The process involves discharging the chlorine-rich extract phase under qualified batch conditions, then desolvating the final extraction stage resin phase outlet liquid under reduced pressure to obtain a low-chlorine epoxy resin product. This yields the final chlorine mass concentration, final dechlorination rate, and extraction load results, specifically including: Under the condition of load balance and qualified batch, the extract phase output from the mixing and phase separation unit corresponding to the first extraction stage is discharged as the chlorine-rich extract phase. Under the condition of a load-balanced qualified batch, the outlet liquid of the final extraction stage resin phase is retained as the low-chlorine resin liquid; Under load-balanced qualified batch conditions, the low-chlorine resin solution is subjected to desolventizing under reduced pressure to remove the main solvent and residual extractant, thereby obtaining the low-chlorine epoxy resin product. The actual outlet chlorine mass concentration of the final extraction stage resin phase is taken as the final chlorine mass concentration. Under the condition of load balance and qualified batch, the initial chlorine mass concentration of the resin solution is subtracted from the final chlorine mass concentration to obtain the final chlorine reduction concentration. The final chlorine reduction concentration is then divided by the initial chlorine mass concentration of the resin solution, with the final chlorine reduction concentration as the dividend and the initial chlorine mass concentration of the resin solution as the divisor, to obtain the final chlorine removal rate. Under the condition of load balance and qualified batch, the output is low-chlorine epoxy resin product, final chlorine mass concentration, final dechlorination rate, actual chlorine transfer load of each extraction stage, actual total chlorine transfer amount and chlorine load at the outlet of the first extraction stage extraction phase; Under the condition of load balancing and non-conforming batch, output the final chlorine mass concentration, the actual chlorine transfer load of each extraction stage, the actual total chlorine transfer amount, and the conclusion that it is not released as a low-chlorine epoxy resin product.

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