Intermittent regeneration-based multi-stage desorbed resin cyclic regeneration system and method

Abstract

The invention relates to the technical field of secondary refrigerant ethylene glycol, and discloses a multistage desorbed resin cyclic regeneration system and method based on intermittent regeneration, the system comprises a pretreatment unit, an automatic control unit, a regeneration unit and a multistage resin treatment unit, the pretreatment unit is respectively connected with the automatic control unit and the multi-stage resin treatment unit, the automatic control unit is also connected with the multi-stage resin treatment unit, and the regeneration unit is connected with the multi-stage resin treatment unit. According to the multi-stage desorbed resin cyclic regeneration system and method based on intermittent regeneration, through vacuum pressure reduction and drying, pulse regeneration, variable-temperature washing and ultrasonic activation and combination of PLC automation and a multi-stage resin differentiation strategy, efficient resin regeneration is achieved, the ion removal capacity is improved, energy consumption and loss are reduced, different water qualities are adapted, and high-efficiency regeneration of the resin is achieved. And the system stability and the industrial application value are enhanced.

Description

Technical Field

[0001] This invention relates to the field of ethylene glycol refrigerant technology, and particularly to a multi-stage deionized resin recycling system and method based on intermittent regeneration. Background Technology

[0002] In the field of ethylene glycol refrigerant purification, ion exchange resins are the core functional materials for removing impurities such as ammonia and metal ions from wastewater. They achieve deep purification of complex impurity systems through specific adsorption reactions between ion exchange groups and metal cations such as ammonium, sodium, calcium, magnesium, and iron, as well as anions such as sulfate and chloride. The regeneration efficiency of the resin directly affects the operational economy and treatment reliability of the purification system: when the resin is saturated, inefficient regeneration leads to a significant decrease in ion removal capacity, resulting in excessive ion content in the treated ethylene glycol, which in turn exacerbates equipment corrosion and heat transfer efficiency degradation in the refrigerant system. Simultaneously, extended regeneration cycles increase the frequency of resin replacement and reagent consumption, leading to higher treatment costs. Furthermore, the control of ethylene glycol loss and the degree of resin exchange capacity recovery during regeneration directly affect the material circulation efficiency and continuous operation stability of the purification process. Therefore, optimizing resin regeneration technology is a crucial step in improving the purification efficiency of ethylene glycol refrigerant.

[0003] Existing technologies and traditional resin regeneration methods suffer from problems such as long regeneration cycles, low ion removal rates, and significant ethylene glycol losses. This is particularly problematic when dealing with the diverse water qualities generated by multiple independent cooling systems in methionine production (e.g., complex impurity systems with high ammonia nitrogen and high sulfate levels), making efficient adaptation difficult. Furthermore, conventional regeneration processes rely on manual operation, lacking dynamic monitoring and automated control of resin failure states. The regeneration process also involves high acid and alkali consumption and energy consumption, failing to meet the economic and environmental requirements of industrial production. In addition, existing technologies lack sufficient synergistic mechanisms for pretreatment of high-turbidity wastewater and resin regeneration, leading to increased resin susceptibility to suspended solids contamination and shortened lifespan. Summary of the Invention

[0004] This invention provides a multi-stage ion-removing resin recycling system and method based on intermittent regeneration. By using vacuum depressurization and drying, pulse regeneration, variable temperature rinsing and ultrasonic activation, combined with PLC automation and a multi-stage resin differentiation strategy, it achieves efficient resin regeneration, improves ion removal capacity, reduces energy consumption and losses, adapts to different water qualities, and enhances system stability and industrial application value.

[0005] This invention provides a multi-stage deionized resin recycling system based on intermittent regeneration, comprising a pretreatment unit, an automatic control unit, a regeneration unit, and a multi-stage resin treatment unit. The pretreatment unit is connected to both the automatic control unit and the multi-stage resin treatment unit. The automatic control unit is also connected to the multi-stage resin treatment unit. The regeneration unit is connected to the multi-stage resin treatment unit.

[0006] The pretreatment unit includes a GW transfer pump, a decolorization tank, and an automatic backwash filter. The automatic control unit includes a PLC control cabinet, a conductivity meter, a pH sensor, a level sensor, a turbidity meter, and an electromagnetic flow meter. The regeneration unit includes a sulfuric acid storage tank, a sodium hydroxide storage tank, a pulse regeneration pump, a demineralized water tank, a flushing pump, a vacuum unit, and an ultrasonic control cabinet. The multi-stage resin treatment unit includes a resin tank, a cation exchange tank, an anion exchange tank, a first buffer tank, a second buffer tank, and a temporary storage tank.

[0007] The refrigerant ethylene glycol to be treated is transferred from the GW and pumped into the decolorization tank. After flocculation and turbidity removal in the decolorization tank, it is filtered by the automatic backwash filter to remove suspended solids. The filtered liquid enters different treatment routes according to the water quality. The waste liquid of the first-stage system with high ammonia and low sulfate is deaminated in the resin tank, and then the liquid after decation of the cation bed tank of the waste liquid of the second-stage system with high ammonia and high sulfate is respectively entered into the first buffer tank and the second buffer tank to adjust the pH. After that, they enter the anion bed tank together to deanionize. The qualified ethylene glycol after treatment is stored in the temporary storage tank and reused in the original system.

[0008] When the resin is saturated with adsorption, the PLC control cabinet automatically triggers the regeneration process based on the conductivity. The resin tank is then dried under negative pressure by a vacuum unit, and then regenerated by pulse with sulfuric acid or sodium hydroxide solution. The process is combined with temperature-controlled rinsing, ultrasonic activation, and gradient water replenishment to complete the resin regeneration. The regenerated resin can then be reused.

[0009] Furthermore, in the pretreatment unit, the GW transfer pump is connected to the decolorization tank and the multi-stage resin treatment unit, the decolorization tank is connected to the automatic backwash filter and the automatic control unit, and the automatic backwash filter is connected to the multi-stage resin treatment unit and the automatic control unit.

[0010] Furthermore, in the preprocessing unit,

[0011] The GW transfer pump is used to pump the refrigerant ethylene glycol to be treated from the original system into the decolorization tank, and its flow rate is adjusted according to the system size.

[0012] The decolorization tank is used to add 20% ammonia water to adjust the pH to 9.5, and at the same time add ferrous sulfate, activated carbon and PAM for flocculation and turbidity removal. Its bottom outlet is connected to the automatic backwash filter.

[0013] The automatic backwash filter is used to filter suspended solids in the effluent from the decolorization tank. When the pressure difference is >0.1MPa, it automatically backwashes, and the backwash water is recycled to the wastewater treatment tank.

[0014] Furthermore, the multi-stage resin processing unit includes a first branch and a second branch;

[0015] In the first branch, the automatic backwash filter is connected to the resin tank, the resin tank is connected to the first buffer tank, and the first buffer tank is connected to the analgesic tank;

[0016] In the second branch, the automatic backwash filter is connected to the cation bed tank, the cation bed tank is connected to the second buffer tank, and the second buffer tank is connected to the anion bed tank;

[0017] The anal bed tank is connected to the temporary storage tank, and the temporary storage tank is connected to the GW transfer pump;

[0018] The resin tank, cation bed tank, and anion bed tank are all connected to the regeneration unit, and the resin tank, anion bed tank, first buffer tank, second buffer tank, and temporary storage tank are all connected to the automatic control unit.

[0019] Furthermore, in the multi-stage resin treatment unit,

[0020] The resin tank is used for ammonia removal. It is filled with macroporous weak acid resin and removes ammonium ions through ion exchange. It is equipped with a conical bottom and a water distributor to ensure that water flows evenly through the resin layer to improve the ammonia removal efficiency.

[0021] The cation bed tank is used for decation and is filled with a strong acidic cation exchange resin to remove cations including sodium ions, calcium, magnesium and iron ions.

[0022] The anion exchange tank is used for deionization. It is filled with a strong basic anion exchange resin to remove sulfate and chloride ions. When connected in series with the cation exchange tank, the pH is adjusted to 5-7 through the second buffer tank.

[0023] The first buffer tank is used to temporarily store the water effluent from the resin tank and balance flow fluctuations; the second buffer tank is equipped with a pH sensor and automatically adds 5% sulfuric acid to adjust the pH.

[0024] The temporary storage tank is used to store processed ethylene glycol, which is connected to the GW transfer pump via a pipeline for reuse in the methionine GW system.

[0025] Furthermore, in the regeneration unit, the sulfuric acid storage tank and the sodium hydroxide storage tank are both connected to the pulse regeneration pump, the pulse regeneration pump is connected to the water distributor at the bottom of the resin tank, the demineralized water tank is connected to the flushing pump, the flushing pump is connected to the water inlet at the top of the resin tank, the vacuum unit is connected to the air extraction port at the top of the resin tank, and the ultrasonic control cabinet is connected to the vibrator on the outer wall of the resin tank.

[0026] The pulse regeneration pump is also connected to the cation bed tank and the anion bed tank, the flushing pump is also connected to the cation bed tank and the anion bed tank, the vacuum unit is also connected to the cation bed tank and the anion bed tank, and the ultrasonic control cabinet is also connected to the cation bed tank and the anion bed tank.

[0027] Furthermore, in the regeneration unit,

[0028] The sulfuric acid storage tank and sodium hydroxide storage tank are used to store the regenerated solution, which is injected into the resin tank through the pulse regeneration pump to remove ions adsorbed by the resin.

[0029] The pulse regeneration pump starts and stops at a set frequency to form a pulse flow, which, in conjunction with the aeration at the bottom of the tank, enhances the contact between the regeneration liquid and the resin.

[0030] The demineralized water tank is used to store demineralized water. After regeneration, the resin is rinsed to neutral by the rinsing pump. The rinsing pump adjusts the water temperature according to a set temperature gradient during temperature rinsing.

[0031] The vacuum unit is used to generate a negative pressure of -0.05MPa according to a set pumping rate, quickly dry the resin, and recover the residual ethylene glycol to the temporary storage tank.

[0032] The ultrasonic control cabinet is used to output 40kHz high-frequency vibration to activate the blocking ions in the resin pores and restore the resin exchange capacity.

[0033] Furthermore, in the automatic control unit, the PLC control cabinet is connected to the conductivity meter, pH sensor, liquid level sensor, turbidity meter, and electromagnetic flow meter respectively. The conductivity meter is connected to the resin tank, cation exchange tank, and anion exchange tank respectively. The pH sensor is connected to the decolorization tank, the first buffer tank, and the second buffer tank respectively. The liquid level sensor is connected to the first buffer tank, the second buffer tank, and the temporary storage tank respectively. The turbidity meter is connected to the automatic backwash filter.

[0034] Furthermore, in the automatic control unit,

[0035] The PLC control cabinet is used to preset the regeneration program, automatically trigger regeneration based on conductivity, and coordinate the adjustment of acid and alkali pumps, flushing pumps, and vacuum units.

[0036] The conductivity meter is installed at the inlet and outlet of the resin tank to monitor the ion concentration in real time. When the conductivity of the effluent exceeds the standard, an alarm is triggered and the regeneration process is switched.

[0037] The pH sensor is used to monitor pH = 9.5 ± 0.5 in the decolorization tank and pH = 5 to 7 in the buffer tank, and to automatically control the amount of sulfuric acid / ammonia added.

[0038] The liquid level sensor is used to link the GW transfer pump and the temporary storage tank transfer pump to prevent overflow or evacuation.

[0039] The turbidity meter is used to monitor the turbidity at the outlet of the automatic backwash filter and trigger backwashing; the electromagnetic flow meter is used to monitor the pulse flow of the regenerated liquid pipeline to ensure accurate regenerated liquid dosage.

[0040] The present invention also provides a multi-stage deionizer resin recycling method based on intermittent regeneration, which, based on the multi-stage deionizer resin recycling system based on intermittent regeneration described above, specifically includes:

[0041] S1. The PLC control cabinet monitors the conductivity of the resin tank inlet and outlet in real time. When the conductivity of the cation bed tank outlet water exceeds the first set value, the anion bed tank exceeds the second set value, or the resin tank exceeds the third set value, or when the time since the last regeneration exceeds the first set time, the regeneration program is automatically triggered, the processing water inlet valve is closed, and the process is switched to the regeneration process.

[0042] S2. Start the vacuum unit to form a negative pressure circulation through the air extraction port at the top of the resin tank and the water distributor at the bottom of the cone, and discharge the residual ethylene glycol in the resin gap. The residual liquid is recovered to the temporary storage tank through the pipeline.

[0043] S3. Start the corresponding regenerated liquid storage tank according to the resin type, and inject the regenerated liquid into the pulse regeneration pump at a set flow rate. Pause once every 10 minutes to form a pulse flow. At the same time, the aeration device at the bottom of the tank is started to enhance the contact between the regenerated liquid and the resin. The cation bed tank removes sodium ions, the anion bed tank removes sulfate ions, and the resin tank removes ammonium ions.

[0044] S4. The desalination tank is flushed with a flushing pump at a gradient of 30℃→50℃→25℃: the first section of 30℃ water dissolves residual acid and alkali on the surface, the middle section of 50℃ water activates the resin pores, and the last section of 25℃ water lowers the temperature of the active sites. The flushing continues until the pH of the effluent is 7±0.5 and the conductivity is less than the fourth set value.

[0045] S5. Turn on the ultrasonic control cabinet, and the 40kHz transducer on the outer wall of the resin tank will continue to act for the second set time to break up the insoluble ions in the resin pores through cavitation effect and restore the exchange capacity; then inject ethylene glycol demineralized water into the resin tank, replenish water in three stages, and let it stand for circulation rinsing.

[0046] S6. After the regeneration process is completed, the PLC automatically switches the resin tank to the treatment state. The first-phase high ammonia waste liquid is preferentially treated through the resin tank → anion bed tank → cation bed tank, while the second-phase high sulfate waste liquid follows the route of cation bed tank → anion bed tank. Differentiated regeneration and treatment cycles are achieved through PLC scheduling.

[0047] The beneficial effects of this invention are as follows:

[0048] This invention significantly improves resin regeneration efficiency and ion removal capability through the synergistic effect of vacuum depressurization and pulse regeneration technology, achieving deep removal of impurities such as ammonia and metal ions from the refrigerant ethylene glycol. The combination of variable-temperature rinsing and ultrasonic activation effectively restores the resin exchange capacity and extends the regeneration cycle, while reducing the consumption of reagents and water. Through PLC automated control and multi-stage resin differentiated operation strategies, the system not only achieves fully automated dynamic regulation of the regeneration process but also accurately adapts to the resin regeneration needs under different water quality conditions, greatly reducing manual intervention and operational errors. Optimized equipment structure, such as the conical bottom water distributor design and anti-corrosion treatment, further enhances the stability and reliability of system operation, significantly reducing the overall operating cost and material loss of ethylene glycol purification treatment, and enhancing the environmental adaptability and industrial application value of the process. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of the multi-stage deionized resin recycling system based on intermittent regeneration in this invention.

[0050] Figure 2 This is a schematic diagram of the process of the multi-stage deionized resin recycling method based on intermittent regeneration in this invention.

[0051] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0053] Ethylene glycol has a boiling point of 197.3℃ and a melting point of -12.9℃. It is miscible with water in any proportion. When miscible with water, its freezing point drops significantly, making it suitable as a refrigerant. However, under long-term operation, ethylene glycol undergoes chemical reactions and physical changes, causing it to turn yellow or red and increasing the amount of insoluble substances. This leads to a decrease in heat transfer efficiency, an increase in operating costs, and exacerbates equipment corrosion. Ethylene glycol undergoes oxidation, eventually producing oxalic acid via intermediates such as hydroxyacetaldehyde, glyoxal, glycolic acid, or aldehyde acetic acid, leading to system acidification and exacerbating equipment corrosion. Ammonia is commonly used in refrigerants for energy transfer with diethanol; however, during long-term use, ammonia may escape into ethylene glycol, further corroding equipment made of aluminum, iron, or copper. During long-term cooling processes, ethylene glycol may introduce acidic or alkaline media under varying operating conditions, which, if left untreated, can also cause corrosion of metal equipment. Furthermore, prolonged use of ethylene glycol may lead to microbial growth, and the introduction of impurities and unknown contaminants can create insoluble impurities that suspend / emulsify throughout the ethylene glycol system, reducing heat exchange efficiency. Methionine GW faces these issues and requires treatment before it can be used efficiently.

[0054] GW has four systems, two at -10℃ and two at -20℃, which are separate systems. The impurities introduced during use are also different for each system, as shown in the data below.

[0055]

[0056]

[0057] The problem is as follows:

[0058] a. If the turbidity is too high, an insulation layer will form on the heat exchange tube wall due to the accumulation of temperature difference, or the internal heat transfer efficiency may be poor.

[0059] b. Excessive ion levels can cause corrosion to the pipes during use, exacerbating the problem.

[0060] c. The four systems are all independent and have different processing methods. The introduced moisture and lost ethylene glycol need to be calculated and replenished separately.

[0061] d. All four systems operate independently, and each has its own advantages and disadvantages, whether it is continuous or intermittent processing.

[0062] like Figure 1As shown, this invention provides a multi-stage deionized resin recycling system based on intermittent regeneration, including a pretreatment unit, an automatic control unit, a regeneration unit, and a multi-stage resin treatment unit. The pretreatment unit is connected to both the automatic control unit and the multi-stage resin treatment unit. The automatic control unit is also connected to the multi-stage resin treatment unit, and the regeneration unit is connected to the multi-stage resin treatment unit. The pretreatment unit includes a GW transfer pump, a decolorization tank, and an automatic backwash filter. The automatic control unit includes a PLC control cabinet, a conductivity meter, a pH sensor, a level sensor, a turbidity meter, and an electromagnetic flowmeter. The regeneration unit includes a sulfuric acid storage tank, a sodium hydroxide storage tank, a pulse regeneration pump, a demineralized water tank, a flushing pump, a vacuum unit, and an ultrasonic control cabinet. The multi-stage resin treatment unit includes a resin tank, a cation exchange tank, an anion exchange tank, a first buffer tank, a second buffer tank, and a temporary storage tank.

[0063] The processing flow of this invention is as follows:

[0064] The refrigerant ethylene glycol to be treated is transferred from the GW and pumped into the decolorization tank. After flocculation and turbidity removal in the decolorization tank, it is filtered by the automatic backwash filter to remove suspended solids. The filtered liquid enters different treatment routes according to the water quality. The waste liquid of the first-stage system with high ammonia and low sulfate is deaminated in the resin tank, and then the liquid after decation of the cation bed tank of the waste liquid of the second-stage system with high ammonia and high sulfate is respectively entered into the first buffer tank and the second buffer tank to adjust the pH. After that, they enter the anion bed tank together to deanionize. The qualified ethylene glycol after treatment is stored in the temporary storage tank and reused in the original system.

[0065] When the resin is saturated with adsorption, the PLC control cabinet automatically triggers the regeneration process based on the conductivity. The resin tank is then dried under negative pressure by a vacuum unit, and then regenerated by pulse with sulfuric acid or sodium hydroxide solution. The process is combined with temperature-controlled rinsing, ultrasonic activation, and gradient water replenishment to complete the resin regeneration. The regenerated resin can then be reused.

[0066] (1) Preprocessing unit

[0067] The pretreatment unit includes a GW transfer pump, a decolorizing tank, and an automatic backwash filter. The GW transfer pump is connected to the decolorizing tank and the multi-stage resin treatment unit, respectively. The decolorizing tank is connected to the automatic backwash filter and the automatic control unit, respectively. The automatic backwash filter is connected to the multi-stage resin treatment unit and the automatic control unit, respectively.

[0068] The functions of each processing device are as follows:

[0069] GW transfer pump: The refrigerant ethylene glycol (methionine GW system waste liquid) to be treated is pumped from the original system into the decolorization tank. The flow rate is adjusted according to the system scale (design flow rate 10m³ / h). 3 / h).

[0070] Decolorization tank: Designed with rubber-lined carbon steel, equipped with an internal stirrer for adding 20% ​​ammonia to adjust the pH to 9.5, and simultaneously adding ferrous sulfate, activated carbon, and PAM for flocculation and turbidity removal. The conical bottom design (60° cone angle) facilitates floc settling, and the bottom outlet is connected to a filter.

[0071] Automatic backwash filter: filters suspended solids in the decolorization tank effluent (turbidity reduced from >600 NTU to <50 NTU), preventing resin tank contamination. Automatic backwashing occurs when the pressure difference is >0.1 MPa, and the backwash water is recycled to the wastewater treatment tank.

[0072] (2) Multi-stage resin treatment unit

[0073] The multi-stage resin treatment unit includes a resin tank, a cation exchange tank, an anion exchange tank, a first buffer tank, a second buffer tank, and a temporary storage tank. Its equipment composition is divided into a first branch and a second branch.

[0074] In the first branch, the automatic backwash filter is connected to the resin tank, the resin tank is connected to the first buffer tank, and the first buffer tank is connected to the analgesic tank;

[0075] In the second branch, the automatic backwash filter is connected to the cation bed tank, the cation bed tank is connected to the second buffer tank, and the second buffer tank is connected to the anion bed tank;

[0076] Finally, the anion bed tank is connected to the temporary storage tank, the temporary storage tank is connected to the GW transfer pump, the resin tank, the cation bed tank, and the anion bed tank are all connected to the regeneration unit, and the resin tank, the anion bed tank, the first buffer tank, the second buffer tank, and the temporary storage tank are all connected to the automatic control unit;

[0077] The functions of each processing device are as follows:

[0078] Resin Tank: Specifically designed for ammonia removal, filled with macroporous weakly acidic resin. It removes ammonium ions (including ammonia) through ion exchange. The influent ammonia content is 520–4417 ppm, and the effluent ammonia content is ≤50 ppm. The conical bottom + water distributor design (perforated plate + filter screen) ensures that the water flows evenly through the resin layer, improving ammonia removal efficiency.

[0079] The cation exchange tank is filled with a strong acidic cation exchange resin to remove cations such as sodium, calcium, magnesium, and iron. The influent cation concentration (e.g., sodium ion 211–777 ppm) is maintained at ≤10 ppm. The rubber-lined carbon steel material resists corrosion from 5% sulfuric acid regeneration solution.

[0080] The anion exchange tank, filled with strongly basic anion exchange resin, removes sulfate and chloride ions. The influent sulfate concentration is 485–445 ppm, and the effluent sulfate concentration is ≤50 ppm. When connected in series with a cation exchange tank, a buffer tank is used to adjust the pH to 5–7 to optimize ion exchange efficiency.

[0081] First and second buffer tanks: temporarily store the effluent from the resin tank to balance flow fluctuations; equipped with a pH sensor, automatically adding 5% sulfuric acid to adjust the pH (e.g., if the pH of the effluent from the cation exchange bed is <3, it is adjusted to 5 via the buffer tank).

[0082] Temporary storage tank: Stores processed ethylene glycol (turbidity <10 NTU, ion concentration meets standards), which is then recycled back to the methionine GW system via pipeline, reducing the need for new ethylene glycol replenishment.

[0083] (3) Regeneration unit

[0084] The regeneration unit includes a sulfuric acid storage tank, a sodium hydroxide storage tank, a pulse regeneration pump, a demineralized water tank, a flushing pump, a vacuum unit, and an ultrasonic control cabinet. The sulfuric acid and sodium hydroxide storage tanks are both connected to the pulse regeneration pump, which is connected to the water distributor at the bottom of the resin tank. The demineralized water tank is connected to the flushing pump, which is connected to the water inlet at the top of the resin tank. The vacuum unit is connected to the air extraction port at the top of the resin tank. The ultrasonic control cabinet is connected to the vibrator on the outer wall of the resin tank. The pulse regeneration pump is also connected to the cation exchange tank and the anion exchange tank; the flushing pump is also connected to the cation exchange tank and the anion exchange tank; the vacuum unit is also connected to the cation exchange tank and the anion exchange tank; and the ultrasonic control cabinet is also connected to the cation exchange tank and the anion exchange tank.

[0085] The functions of each processing device are as follows:

[0086] Sulfuric acid / sodium hydroxide storage tank: Stores 5% regenerated solution, which is injected into the resin tank through a pulse regeneration pump (flow rate 5L / min) to remove ions adsorbed by the resin (such as sulfuric acid regeneration cation bed, sodium hydroxide regeneration anion bed).

[0087] Pulse regeneration pump: Starts and stops at a frequency of 10 minutes / time to form a pulse flow. Combined with aeration at the bottom of the tank, it enhances the contact between the regenerated liquid and the resin, improving the regeneration efficiency by 30%.

[0088] Demineralized water tank / rinsing pump: Stores demineralized water and rinses the resin to neutral (pH = 7 ± 0.5) after regeneration. During temperature-controlled rinsing, the water temperature is adjusted in a gradient of 30℃ → 50℃ → 25℃.

[0089] Vacuum unit: pumping speed 100m 3 / h, generating a negative pressure of -0.05MPa, rapidly drying the resin, recovering residual ethylene glycol to a temporary storage tank, reducing the loss rate from 5% to 2%.

[0090] Ultrasonic control cabinet: Outputs 40kHz high-frequency vibration to activate blocked ions in the resin pores, restore the resin exchange capacity, and extend the regeneration cycle.

[0091] (4) Automatic control unit

[0092] The automatic control unit includes a PLC control cabinet, a conductivity meter, a pH sensor, a level sensor, a turbidity meter, and an electromagnetic flow meter. The PLC control cabinet is connected to the conductivity meter, pH sensor, level sensor, turbidity meter, and electromagnetic flow meter. The conductivity meter is connected to the resin tank, cation exchange tank, and anion exchange tank. The pH sensor is connected to the decolorization tank, the first buffer tank, and the second buffer tank. The level sensor is connected to the first buffer tank, the second buffer tank, and the temporary storage tank. The turbidity meter is connected to the automatic backwash filter.

[0093] The functions of each processing device are as follows:

[0094] PLC control cabinet: It has a preset five-stage regeneration program, which automatically triggers regeneration based on conductivity (>10μS / cm) and adjusts the acid and alkali pumps, flushing pumps, and vacuum unit in conjunction.

[0095] Conductivity meter: Installed at the inlet and outlet of the resin tank to monitor ion concentration in real time. When the conductivity of the effluent exceeds the standard, an alarm is triggered and the regeneration process is switched.

[0096] pH sensor: Monitors pH = 9.5 ± 0.5 in the decolorization tank and pH = 5 to 7 in the buffer tank, automatically controlling the amount of sulfuric acid / ammonia added.

[0097] Liquid level sensor: Magnetic float level gauges are installed in the buffer tank and temporary storage tank, which are linked to the GW transfer pump and the temporary storage tank transfer pump to prevent overflow or cavitation.

[0098] Turbidity meter / electromagnetic flow meter: Backwashing is triggered when the turbidity at the filter outlet is >10 NTU; the regenerated liquid pipeline flow meter monitors the pulse flow to ensure accurate regenerated liquid dosage.

[0099] The normal processing flow of this invention is as follows: GW waste liquid → decolorization tank flocculation → filter turbidity removal → resin tank ammonia removal / cation bed tank cation removal → buffer tank conditioning → anion bed tank anion removal → temporary storage tank reuse.

[0100] Regeneration trigger condition: When the conductivity of the cation bed effluent from the cation bed tank is >10μS / cm, the PLC automatically switches to the regeneration process: vacuum drying → acid-base pulse regeneration → variable temperature rinsing → ultrasonic activation → gradient water replenishment. After regeneration is completed, it switches back to the treatment process.

[0101] In this invention, the first-phase GW1 / GW2 (high ammonia) process follows a route of resin tank → cation exchange tank → anion exchange tank (first branch), while the second-phase GW1 / GW2 (high sulfate) process follows a route of cation exchange tank → anion exchange tank (second branch). The PLC automatically allocates reagents based on the water quality database, with a reagent dosage error of ≤5%. Through the coordinated connection of the above units and equipment, efficient turbidity removal, deionization, and resin regeneration and recycling of the refrigerant ethylene glycol are achieved, greatly improving treatment efficiency.

[0102] like Figure 2 As shown, this invention also provides a multi-stage deionized resin recycling method based on intermittent regeneration. Based on the aforementioned multi-stage deionized resin recycling system based on intermittent regeneration, this method utilizes the principle of "five-step recycling + multi-stage resin synergy," achieving intermittent regeneration of the resin tank through PLC automatic control, thus solving the problem of resin ion saturation failure in ethylene glycol processing. The regeneration cycle is automatically triggered based on conductivity (>10 μS / cm), shortening the single-batch regeneration time and reducing ethylene glycol loss rate.

[0103] The method specifically includes the following steps:

[0104] S1. Resin Failure Detection and Regeneration Triggering

[0105] The PLC control cabinet monitors the conductivity of the resin tank inlet and outlet in real time. When the conductivity of the cation bed tank outlet water is >10μS / cm, the conductivity of the anion bed tank outlet water is >15μS / cm, or the conductivity of the resin tank outlet water is >20μS / cm, or when the resin tank has been regenerated for more than 20 days, or the anion bed tank and cation bed tank have been regenerated for more than 15 days, the regeneration program is automatically triggered, the treatment water inlet valve is closed, and the process is switched to the regeneration process.

[0106] S2, Vacuum Pressure Reduction Drying Resin

[0107] The vacuum unit (-0.05MPa) is started, creating a negative pressure circulation through the air extraction port at the top of the resin tank and the conical bottom water distributor to quickly remove residual ethylene glycol from the resin gaps. The residual liquid is then recovered to the temporary storage tank via pipeline, reducing the ethylene glycol loss rate. The conical bottom design and water distributor ensure uniform drying of the resin layer, preventing liquid accumulation.

[0108] S3, acid-base pulse regenerated ion exchange resin

[0109] The corresponding regenerated solution storage tank (5% sulfuric acid / sodium hydroxide) is activated according to the resin type. The pulse regeneration pump injects the regenerated solution at a flow rate of 5 L / min, pausing every 10 minutes to create a pulse flow. Simultaneously, the aeration device at the bottom of the tank is activated to enhance the contact between the regenerated solution and the resin. The cation exchange tank removes cations such as sodium ions, the anion exchange tank removes anions such as sulfate ions, and the resin tank removes ammonium ions (including ammonia), thereby improving the ion removal rate.

[0110] S4. Variable temperature rinsing to restore resin activity

[0111] The demineralized water tank uses a flushing pump to flush the resin in a gradient of 30℃→50℃→25℃: the first stage uses 30℃ water to dissolve residual acids and alkalis on the surface, the middle stage uses 50℃ water to activate the resin pores, and the final stage uses 25℃ water to lower the temperature of the active sites. Flushing continues until the effluent pH is 7±0.5 and the conductivity is <5μS / cm, reducing water consumption.

[0112] S5, Ultrasonic Activation and Gradient Hydration

[0113] Turn on the ultrasonic control cabinet, and let the 40kHz transducer on the outer wall of the resin tank work continuously for 20 minutes to break up the insoluble ions (such as calcium oxalate) in the resin pores through cavitation effect, restoring 15% of the exchange capacity; then inject demineralized water containing 5% ethylene glycol into the resin tank, replenish water in three stages (20%→50%→100% liquid level), and let it stand for circulation rinsing to avoid osmotic pressure damage to the resin.

[0114] S6. Regeneration complete and system switchover

[0115] After the regeneration process is completed, the PLC automatically switches the resin tank to the treatment state and simultaneously starts the standby resin tank to continue processing ethylene glycol. To address the differences in water quality across the four GW systems, the high-ammonia wastewater from Phase I is preferentially treated via resin tank → anion bed tank → cation bed tank, while the high-sulfate wastewater from Phase II follows the cation bed tank → anion bed tank route. Differentiated regeneration and treatment cycles are achieved through PLC scheduling.

[0116] This invention significantly improves resin regeneration efficiency and ion removal capability through the synergistic effect of vacuum depressurization and pulse regeneration technology, achieving deep removal of impurities such as ammonia and metal ions from the refrigerant ethylene glycol. The combination of variable-temperature rinsing and ultrasonic activation effectively restores the resin exchange capacity and extends the regeneration cycle, while reducing the consumption of reagents and water. Through PLC automated control and multi-stage resin differentiated operation strategies, the system not only achieves fully automated dynamic regulation of the regeneration process but also accurately adapts to the resin regeneration needs under different water quality conditions, greatly reducing manual intervention and operational errors. Optimized equipment structure, such as the conical bottom water distributor design and anti-corrosion treatment, further enhances the stability and reliability of system operation, significantly reducing the overall operating cost and material loss of ethylene glycol purification treatment, and enhancing the environmental adaptability and industrial application value of the process.

[0117] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0118] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A multi-stage deionizer resin recycling system based on intermittent regeneration, characterized in that, It includes a pretreatment unit, an automatic control unit, a regeneration unit, and a multi-stage resin treatment unit. The pretreatment unit is connected to the automatic control unit and the multi-stage resin treatment unit. The automatic control unit is also connected to the multi-stage resin treatment unit. The regeneration unit is connected to the multi-stage resin treatment unit. The pretreatment unit includes a GW transfer pump, a decolorization tank, and an automatic backwash filter. The automatic control unit includes a PLC control cabinet, a conductivity meter, a pH sensor, a level sensor, a turbidity meter, and an electromagnetic flow meter. The regeneration unit includes a sulfuric acid storage tank, a sodium hydroxide storage tank, a pulse regeneration pump, a demineralized water tank, a flushing pump, a vacuum unit, and an ultrasonic control cabinet. The multi-stage resin treatment unit includes a resin tank, a cation exchange tank, an anion exchange tank, a first buffer tank, a second buffer tank, and a temporary storage tank. The refrigerant ethylene glycol to be treated is transferred from the GW and pumped into the decolorization tank. After flocculation and turbidity removal in the decolorization tank, it is filtered by the automatic backwash filter to remove suspended solids. The filtered liquid enters different treatment routes according to the water quality. The waste liquid of the first-stage system with high ammonia and low sulfate is deaminated in the resin tank, and then the liquid after decation of the cation bed tank of the waste liquid of the second-stage system with high ammonia and high sulfate is respectively entered into the first buffer tank and the second buffer tank to adjust the pH. After that, they enter the anion bed tank together to deanionize. The qualified ethylene glycol after treatment is stored in the temporary storage tank and reused in the original system. When the resin is saturated with adsorption, the PLC control cabinet automatically triggers the regeneration process based on the conductivity. The resin tank is then dried under negative pressure by a vacuum unit, and then regenerated by pulse with sulfuric acid or sodium hydroxide solution. The process is combined with temperature-controlled rinsing, ultrasonic activation, and gradient water replenishment to complete the resin regeneration. The regenerated resin can then be reused.

2. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 1, characterized in that, In the pretreatment unit, the GW transfer pump is connected to the decolorization tank and the multi-stage resin treatment unit, the decolorization tank is connected to the automatic backwash filter and the automatic control unit, and the automatic backwash filter is connected to the multi-stage resin treatment unit and the automatic control unit.

3. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 2, characterized in that, In the preprocessing unit The GW transfer pump is used to pump the refrigerant ethylene glycol to be treated from the original system into the decolorization tank, and its flow rate is adjusted according to the system size. The decolorization tank is used to add 20% ammonia water to adjust the pH to 9.5, and at the same time add ferrous sulfate, activated carbon and PAM for flocculation and turbidity removal. Its bottom outlet is connected to the automatic backwash filter. The automatic backwash filter is used to filter suspended solids in the effluent from the decolorization tank. When the pressure difference is >0.1MPa, it automatically backwashes, and the backwash water is recycled to the wastewater treatment tank.

4. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 3, characterized in that, The multi-stage resin treatment unit includes a first branch and a second branch; In the first branch, the automatic backwash filter is connected to the resin tank, the resin tank is connected to the first buffer tank, and the first buffer tank is connected to the analgesic tank; In the second branch, the automatic backwash filter is connected to the cation bed tank, the cation bed tank is connected to the second buffer tank, and the second buffer tank is connected to the anion bed tank; The anal bed tank is connected to the temporary storage tank, and the temporary storage tank is connected to the GW transfer pump; The resin tank, cation bed tank, and anion bed tank are all connected to the regeneration unit, and the resin tank, anion bed tank, first buffer tank, second buffer tank, and temporary storage tank are all connected to the automatic control unit.

5. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 4, characterized in that, In the multi-stage resin treatment unit The resin tank is used for ammonia removal. It is filled with macroporous weak acid resin and removes ammonium ions through ion exchange. It is equipped with a conical bottom and a water distributor to ensure that water flows evenly through the resin layer to improve the ammonia removal efficiency. The cation bed tank is used for decation and is filled with a strong acidic cation exchange resin to remove cations including sodium ions, calcium, magnesium and iron ions. The anion exchange tank is used for deionization. It is filled with a strong basic anion exchange resin to remove sulfate and chloride ions. When connected in series with the cation exchange tank, the pH is adjusted to 5-7 through the second buffer tank. The first buffer tank is used to temporarily store the water effluent from the resin tank and balance flow fluctuations; the second buffer tank is equipped with a pH sensor and automatically adds 5% sulfuric acid to adjust the pH. The temporary storage tank is used to store processed ethylene glycol, which is connected to the GW transfer pump via a pipeline for reuse in the methionine GW system.

6. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 5, characterized in that, In the regeneration unit, the sulfuric acid storage tank and the sodium hydroxide storage tank are both connected to the pulse regeneration pump. The pulse regeneration pump is connected to the water distributor at the bottom of the resin tank. The demineralized water tank is connected to the flushing pump. The flushing pump is connected to the water inlet at the top of the resin tank. The vacuum unit is connected to the air extraction port at the top of the resin tank. The ultrasonic control cabinet is connected to the vibrator on the outer wall of the resin tank. The pulse regeneration pump is also connected to the cation bed tank and the anion bed tank, the flushing pump is also connected to the cation bed tank and the anion bed tank, the vacuum unit is also connected to the cation bed tank and the anion bed tank, and the ultrasonic control cabinet is also connected to the cation bed tank and the anion bed tank.

7. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 6, characterized in that, In the regeneration unit The sulfuric acid storage tank and sodium hydroxide storage tank are used to store the regenerated solution, which is injected into the resin tank through the pulse regeneration pump to remove ions adsorbed by the resin. The pulse regeneration pump starts and stops at a set frequency to form a pulse flow, which, in conjunction with the aeration at the bottom of the tank, enhances the contact between the regeneration liquid and the resin. The demineralized water tank is used to store demineralized water. After regeneration, the resin is rinsed to neutral by the rinsing pump. The rinsing pump adjusts the water temperature according to a set temperature gradient during temperature rinsing. The vacuum unit is used to generate a negative pressure of -0.05MPa according to a set pumping rate, quickly dry the resin, and recover the residual ethylene glycol to the temporary storage tank. The ultrasonic control cabinet is used to output 40kHz high-frequency vibration to activate the blocking ions in the resin pores and restore the resin exchange capacity.

8. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 7, characterized in that, In the automatic control unit, the PLC control cabinet is connected to the conductivity meter, pH sensor, liquid level sensor, turbidity meter, and electromagnetic flow meter respectively. The conductivity meter is connected to the resin tank, cation exchange tank, and anion exchange tank respectively. The pH sensor is connected to the decolorization tank, the first buffer tank, and the second buffer tank respectively. The liquid level sensor is connected to the first buffer tank, the second buffer tank, and the temporary storage tank respectively. The turbidity meter is connected to the automatic backwash filter.

9. The multi-stage deionizer resin recycling system based on intermittent regeneration according to claim 8, characterized in that, In the automatic control unit The PLC control cabinet is used to preset the regeneration program, automatically trigger regeneration based on conductivity, and coordinate the adjustment of acid and alkali pumps, flushing pumps, and vacuum units. The conductivity meter is installed at the inlet and outlet of the resin tank to monitor the ion concentration in real time. When the conductivity of the effluent exceeds the standard, an alarm is triggered and the regeneration process is switched. The pH sensor is used to monitor pH = 9.5 ± 0.5 in the decolorization tank and pH = 5 to 7 in the buffer tank, and to automatically control the amount of sulfuric acid / ammonia added. The liquid level sensor is used to link the GW transfer pump and the temporary storage tank transfer pump to prevent overflow or evacuation. The turbidity meter is used to monitor the turbidity at the outlet of the automatic backwash filter and trigger backwashing; the electromagnetic flow meter is used to monitor the pulse flow of the regenerated liquid pipeline to ensure accurate regenerated liquid dosage.

10. A multi-stage deionizer resin recycling method based on intermittent regeneration, characterized in that, Based on any one of claims 1-9, the method of the multi-stage deionizer resin recycling system based on intermittent regeneration specifically includes: S1. The PLC control cabinet monitors the conductivity of the resin tank inlet and outlet in real time. When the conductivity of the cation bed tank outlet water exceeds the first set value, the anion bed tank exceeds the second set value, or the resin tank exceeds the third set value, or when the time since the last regeneration exceeds the first set time, the regeneration program is automatically triggered, the processing water inlet valve is closed, and the process is switched to the regeneration process. S2. Start the vacuum unit to form a negative pressure circulation through the air extraction port at the top of the resin tank and the water distributor at the bottom of the cone, and discharge the residual ethylene glycol in the resin gap. The residual liquid is recovered to the temporary storage tank through the pipeline. S3. Start the corresponding regenerated liquid storage tank according to the resin type, and inject the regenerated liquid into the pulse regeneration pump at a set flow rate. Pause once every 10 minutes to form a pulse flow. At the same time, the aeration device at the bottom of the tank is started to enhance the contact between the regenerated liquid and the resin. The cation bed tank removes sodium ions, the anion bed tank removes sulfate ions, and the resin tank removes ammonium ions. S4. The desalination tank is flushed with a flushing pump at a gradient of 30℃→50℃→25℃: the first section of 30℃ water dissolves residual acid and alkali on the surface, the middle section of 50℃ water activates the resin pores, and the last section of 25℃ water lowers the temperature of the active sites. The flushing continues until the pH of the effluent is 7±0.5 and the conductivity is less than the fourth set value. S5. Turn on the ultrasonic control cabinet, and the 40kHz transducer on the outer wall of the resin tank will continue to act for the second set time to break up the insoluble ions in the resin pores through cavitation effect and restore the exchange capacity; then inject ethylene glycol demineralized water into the resin tank, replenish water in three stages, and let it stand for circulation rinsing. S6. After the regeneration process is completed, the PLC automatically switches the resin tank to the treatment state. The first-phase high ammonia waste liquid is preferentially treated through the resin tank → anion bed tank → cation bed tank, while the second-phase high sulfate waste liquid follows the route of cation bed tank → anion bed tank. Differentiated regeneration and treatment cycles are achieved through PLC scheduling.

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