Ion exchange resin regeneration system and regeneration process using sulfuric acid instead of hydrochloric acid

Abstract

This invention relates to the field of water and steam treatment technology in thermal power plants, and discloses an ion exchange resin regeneration system and process using sulfuric acid instead of hydrochloric acid. The system includes: a sulfuric acid storage unit, a dilution and preparation unit, a regeneration and transportation unit, a resin regeneration tank, a waste liquid collection and treatment unit, and an automatic control unit. The sulfuric acid storage unit is a sealed concentrated sulfuric acid storage tank, equipped with monitoring components and leak-proof structures. The sulfuric acid transportation pipeline is made of sulfuric acid-resistant material, which can effectively prevent the volatilization and escape of concentrated sulfuric acid, monitor the tank level in real time, prevent the risk of leakage and diffusion, and is suitable for long-term storage, transportation, and transportation of sulfuric acid, reducing on-site operational safety hazards. This ion exchange resin regeneration system and process using sulfuric acid instead of hydrochloric acid can effectively reduce acid mist emission, mitigate the corrosion of equipment and facilities by the medium, completely eliminate the safety hazard of chloride ions entering the water and steam system, and simultaneously reduce the difficulty of environmental management of regeneration waste liquid and the safety risks of on-site storage and transportation operations.

Description

Technical Field

[0001] This invention relates to the field of water and steam treatment technology in thermal power plants, specifically to an ion exchange resin regeneration system and regeneration process that uses sulfuric acid instead of hydrochloric acid. Background Technology

[0002] In the chemical water treatment system of thermal power plants, cation exchange resin regeneration is a key process to restore the resin's exchange capacity and ensure the quality of the system's effluent. Existing technologies typically include units for regenerant storage, preparation, transportation, regeneration reaction, and waste liquid treatment, which can complete the regeneration of the failed resin and support the continuous and stable operation of the ion exchange system.

[0003] Currently, hydrochloric acid is commonly used as a regenerator in regeneration systems within the industry. Existing systems are designed with the storage and transport structures in mind, which can meet the basic requirements for reagent transport and resin regeneration. However, hydrochloric acid is highly volatile, and the existing storage and transport structures cannot effectively contain the acid mist. Long-term operation will exacerbate the corrosion of regeneration tanks, pipelines, valves, and surrounding equipment. At the same time, residual chloride ions from regeneration can easily enter the water vapor system with the process, increasing the corrosion risk of metal components in the unit. Chlorine-containing regeneration waste liquid also increases the difficulty of environmental management of wastewater treatment. If the existing system's regenerant is directly replaced with sulfuric acid to avoid chloride ion-related issues, the existing dosing units are mostly single-stage, coarse-grained dosing structures with insufficient concentration control precision. The uniformity of liquid distribution during regeneration is limited, and localized high sulfate concentrations in the resin layer are prone to occur during regeneration. These sulfate ions combine with calcium ions released from resin displacement to form calcium sulfate crystals, causing resin scaling and reduced regeneration efficiency. Furthermore, existing wastewater treatment units only have neutralization processes for conventional acidic wastewater and lack dedicated sulfate disposal capabilities. Adding a separate deep sulfate treatment facility would significantly increase system investment and operating costs. Existing regeneration systems rely heavily on manual control of operating parameters at each stage, which is prone to errors during operation, leading to fluctuations in regeneration conditions and increasing on-site safety risks associated with sulfuric acid media operations. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an ion exchange resin regeneration system and process that uses sulfuric acid to replace hydrochloric acid. This solves the technical problems of existing hydrochloric acid regeneration systems, such as severe acid mist corrosion, chloride ion threats to unit safety, high environmental control pressure, easy resin calcium sulfate scaling after directly replacing sulfuric acid, high cost of sulfate waste liquid disposal, large fluctuations in operating conditions due to manual control, and high operational safety risks.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an ion exchange resin regeneration system using sulfuric acid instead of hydrochloric acid, comprising a sulfuric acid storage unit, a dilution and preparation unit, a regeneration and transportation unit, a resin regeneration tank, a waste liquid collection and treatment unit, and an automatic control unit. The sulfuric acid storage unit is a sealed concentrated sulfuric acid storage tank, equipped with level monitoring devices, temperature monitoring devices, and a leak-proof dike. The sulfuric acid transportation pipeline is made of sulfuric acid-resistant material, effectively preventing the volatilization and escape of concentrated sulfuric acid. It allows for real-time monitoring of the tank's level, temperature, and other operating statuses, preventing leakage and diffusion risks, and is suitable for long-term storage and transportation of sulfuric acid media, reducing on-site operational safety hazards. The dilution and preparation unit connects to demineralized water and concentrated sulfuric acid, and is equipped with an online concentration detection component for preparing dilute sulfuric acid regeneration solution. It allows for real-time closed-loop control of the reagent ratio, ensuring accurate and uniform regeneration solution concentration and avoiding localized excessive concentration of acid leading to calcium sulfate scaling on the resin. The regeneration and conveying unit is equipped with an acid-resistant pump, flow and pressure monitoring components, and distribution components. It uniformly delivers regenerated liquid to each regeneration tank, stably controlling the flow rate and pressure of the regenerated liquid to ensure uniform contact between the resin and the regenerated liquid in each tank and area, thus improving the overall uniformity of resin regeneration. The waste liquid collection and treatment unit is equipped with pH monitoring and neutralization dosing components, and features a desulfurization system co-processing interface that connects to the power plant's desulfurization process water tank. This allows for pH pretreatment of the sulfuric acid regeneration waste liquid before it is connected to the power plant's existing desulfurization system, achieving harmless disposal of sulfate waste liquid and reducing wastewater treatment costs and environmental control pressure. The automatic control unit is connected to the instruments, valves, and pumps of each unit, enabling automated interlocking operation of the entire process of concentrated sulfuric acid feeding, dosing, conveying, regeneration, and rinsing. This reduces human error and improves system stability and operational safety.

[0006] Preferably, the dilution and preparation unit is a two-stage series gradient dilution and preparation mechanism. A first-stage pipeline static mixing and pre-dilution component and a second-stage metering tank homogenization and concentration component are sequentially arranged along the medium flow direction. The first-stage pipeline static mixing and pre-dilution component relies on built-in flow-disrupting elements to ensure thorough turbulent mixing of concentrated sulfuric acid and demineralized water during flow, completing preliminary coarse concentration adjustment and avoiding the problems of localized concentrated acid accumulation and uneven heat release during single-stage dilution. The second-stage metering tank has a built-in circulation homogenization pipeline and a high-precision online concentration detector. The circulation homogenization pipeline is equipped with a small acid-resistant circulation pump, which extracts the liquid from the bottom of the metering tank and returns it to the upper part of the tank, forming forced circulation within the tank. This drives the liquid circulation within the tank, eliminating the phenomenon of concentration stratification at different concentration levels. The online concentration detector feeds real-time concentration data back to the automatic control unit, dynamically adjusting the feed ratio of concentrated sulfuric acid and demineralized water, and performing closed-loop correction of the concentrated sulfuric acid and demineralized water ratio to achieve precise closed-loop control of the output regenerated solution concentration.

[0007] Preferably, the distribution component of the regeneration delivery unit is a pressure-stabilizing and flow-throttling distribution assembly, including an inlet throttling orifice plate and a rear-end pressure-stabilizing buffer tank. The throttling orifice plate throttles and reduces the pressure of the incoming regeneration liquid, while the pressure-stabilizing buffer tank reduces pressure pulsations from the acid-resistant pump, maintaining stable pressure within the main distribution pipe and providing a stable pressure foundation for uniform liquid distribution in each branch pipe. Each output branch pipe is equipped with a flow regulating valve, allowing independent control of the regeneration liquid flow rate in a single branch pipe to adapt to the regeneration requirements of different tanks. Combined with the radial porous water distribution structure at the top of the regeneration tank, the regeneration liquid is evenly distributed along the tank cross-section to the resin layer end face, preventing flow deviation and short-circuit flow. The uniformity deviation of the liquid distribution at the resin layer end face is ≤±5%, ensuring that the entire tank of resin can uniformly contact the regeneration liquid, avoiding problems such as insufficient local regeneration or excessively high local concentrations that induce scaling.

[0008] Preferably, the resin regeneration tank is equipped with a multi-point parameter monitoring component for the resin layer. Multiple sets of conductivity monitoring probes, ion concentration monitoring probes, and temperature monitoring probes are arranged along the height of the resin layer. These probes are positioned at the upper, middle, and lower parts of the resin layer, respectively, to collect real-time data on the conductivity, sulfate concentration, calcium ion concentration, and temperature of the liquid phase within the resin layer at different heights. This allows for a comprehensive understanding of the ion distribution and reaction process within the resin layer during regeneration. The automatic control unit incorporates a calcium sulfate scaling prediction interlock module. Based on real-time monitoring data, it calculates the calcium sulfate supersaturation. Using the calcium sulfate solubility product constant and the current liquid phase ion concentration and temperature parameters, it calculates the real-time supersaturation, quantitatively assessing the scaling risk at various locations within the resin layer. When a warning threshold is reached, it automatically reduces the influent flow rate and concentration. By slowing down the ion replacement rate, it prevents sulfate ions from rapidly combining with calcium ions to form calcium sulfate crystals, thus achieving proactive prevention and control of scaling risks.

[0009] Preferably, the pipelines and valves in the system that come into contact with concentrated and dilute sulfuric acid are made of PTFE-lined or fiberglass-reinforced plastic (FRP). These materials have excellent corrosion resistance to sulfuric acid media, can withstand the erosion of concentrated and dilute sulfuric acid for a long time, avoid equipment leakage and damage caused by acid corrosion, extend equipment service life, and reduce maintenance frequency and operating costs. The instrument probes that come into contact with dilute sulfuric acid are made of Hastelloy alloy, which ensures detection accuracy while having good resistance to dilute sulfuric acid corrosion, ensuring the long-term stability and operational reliability of monitoring data.

[0010] A regeneration process for ion exchange resins using sulfuric acid instead of hydrochloric acid, comprising the above-mentioned ion exchange resin regeneration system using sulfuric acid instead of hydrochloric acid, including: S1. Monitor effluent indicators and initiate regeneration after resin failure. By monitoring the conductivity, sodium ion, and hardness of the ion exchanger effluent online, accurately determine the state of resin exchange capacity depletion, avoiding premature regeneration that wastes reagents or delayed regeneration that affects effluent water quality.

[0011] S2. Backwash the resin layer with deionized water until the effluent is clear. The reverse water flow loosens the compacted resin layer, washes away suspended matter and broken resin particles adsorbed on the resin surface, and provides a uniform and loose resin layer structure for subsequent regeneration, improving the contact effect between the regenerated solution and the resin.

[0012] S3. Dilute concentrated sulfuric acid to prepare dilute sulfuric acid regeneration solution, adjust the ratio online, and accurately control the concentration of regeneration solution through gradient dilution to ensure stable and controllable concentration of regeneration agent to meet the needs of resin regeneration reaction.

[0013] S4. Resin regeneration is completed by introducing regenerating solution in stages and controlling the flow rate. By adjusting the concentration and flow rate of the influent in stages, the formation of calcium sulfate crystals is effectively suppressed while ensuring the depth of resin regeneration.

[0014] S5. Use demineralized water to replace and rinse the residual acid in the resin layer. The demineralized water will push the residual regeneration waste liquid and the displaced metal ions in the resin layer to be discharged, so as to avoid the residual acid and impurities affecting the quality of the subsequent effluent.

[0015] S6. After forward flushing until the water quality meets the standards, the system is put into operation. The high-flow forward flushing thoroughly removes the residual regenerated liquid and regenerated products in the resin layer, ensuring that the effluent water quality meets the operating standards of the power plant's water and steam system.

[0016] S7. Collect waste liquid, neutralize it, and discharge it into the desulfurization system for co-processing. Collect and treat acidic waste liquid generated throughout the regeneration process in a unified manner. Rely on the power plant's existing desulfurization system to achieve harmless disposal of sulfate and reduce environmental disposal costs.

[0017] Preferably, step S3 employs a two-stage gradient dilution process: the concentrated sulfuric acid is initially pre-diluted through static mixing in the first stage, and coarse dilution is rapidly completed using pipeline turbulence, dispersing the heat released during the concentrated sulfuric acid dilution process and avoiding local overheating and sudden concentration changes. Then, it enters the second-stage metering tank for homogenization and concentration adjustment. Through circulation homogenization and closed-loop concentration control, precise fine-tuning is completed to ensure that the output regenerated solution concentration is stable and uniform, and a dilute sulfuric acid regenerated solution with a mass concentration of 2% to 4% is prepared. This concentration range is suitable for the kinetic requirements of the cation resin regeneration reaction, and can effectively control the liquid phase sulfate concentration level, reducing the risk of calcium sulfate scaling from the source.

[0018] Preferably, step S4 employs a concentration-flow rate dual-gradient uplift regeneration method: In the first stage, the resin layer is wetted with a low flow rate and low concentration of regenerated solution, accounting for 20% to 30% of the total regeneration time. During this stage, the calcium ions adsorbed on the resin surface are slowly replaced, and the release rate of calcium ions on the resin surface and in the pores is controlled to prevent local sulfate ions from rapidly combining with calcium ions to form calcium sulfate crystals that adhere to the resin surface. In the second stage, the regeneration is increased to a set concentration and a stable flow rate for continuous regeneration. During this stage, the regenerated solution is ensured to fully contact and react with the resin, deeply replacing the cations adsorbed inside the resin, ensuring that the resin regeneration degree and working exchange capacity meet the operating requirements. When a local calcium sulfate supersaturation of ≥0.8 is detected, the inlet flow rate is automatically reduced by 10% to 20%. By slowing down the ion exchange rate, the local ion concentration peak is reduced, actively eliminating the risk of scaling and balancing regeneration efficiency and anti-scaling effect.

[0019] Preferably, in step S7, the waste liquid is pre-neutralized to pH 4-6 in the collection tank to adjust the acidic waste liquid to a pH range suitable for the desulfurization system influent, avoiding the impact of strong acid on the desulfurization system equipment, slurry microbial community, and absorption efficiency. Then, it is discharged into the power plant's desulfurization process water tank through the co-treatment interface. Sulfate reacts with the calcium-based absorbent in the desulfurization slurry to generate gypsum, which is discharged along with the desulfurization byproducts. The calcium-based absorbent of the power plant's existing desulfurization system is used to solidify sulfate, converting sulfate into desulfurization gypsum byproducts that can be utilized by resources. There is no need to set up a separate deep sulfate treatment facility, realizing the resource-based disposal of waste liquid, significantly reducing the treatment cost of sulfate waste liquid and the environmental control pressure, while reducing the investment and land occupation of new wastewater treatment equipment.

[0020] Preferably, the entire regeneration process is automatically executed by a PLC control system. It can complete the entire process—from failure detection, backwashing, reagent preparation, regeneration, replacement, forward washing, to commissioning—according to preset process parameters, reducing manual intervention and improving the stability and consistency of the regeneration process. Furthermore, the PLC control system has fault alarm, operating parameter storage, and historical curve query functions. It can monitor abnormal parameters such as liquid level, concentration, pressure, and pH in real time and trigger audible and visual alarms, ensuring the inherent safety of sulfuric acid regeneration operations. The parameter storage and historical curve functions facilitate operators in reviewing the regeneration process, conducting process optimization and fault tracing analysis. The regeneration parameters are adaptively adjusted according to the degree of resin failure, allowing for matching corresponding regeneration dosages and durations to resins with different failure depths, saving reagent consumption while ensuring regeneration effectiveness.

[0021] Compared with the prior art, the present invention provides an ion exchange resin regeneration system and regeneration process that uses sulfuric acid instead of hydrochloric acid, which has the following beneficial effects: This ion exchange resin regeneration system and process, which uses sulfuric acid instead of hydrochloric acid as the regenerator, is equipped with a sealed concentrated sulfuric acid storage tank, a monitoring and leak-proof structure, and sulfuric acid-resistant pipelines. It can effectively reduce acid mist emission, mitigate the corrosion of equipment and facilities by the medium, completely eliminate the safety hazard of chloride ions entering the water vapor system, and reduce the difficulty of environmental management of regenerated waste liquid and the safety risks of on-site storage and transportation operations.

[0022] By incorporating a dilution and dosing unit with online concentration detection components and a regeneration and delivery unit with distribution components, the concentration of the regenerated solution can be precisely controlled, ensuring uniform delivery of the regenerated solution to the resin layer of each regeneration tank. This avoids excessively high local sulfate concentrations, effectively inhibits calcium sulfate crystal formation, and guarantees stable and reliable resin regeneration. The wastewater treatment unit is equipped with a co-processing interface with the desulfurization system, enabling the harmless disposal of sulfate wastewater using the existing desulfurization system of the power plant. This eliminates the need for additional deep treatment facilities, reducing wastewater disposal costs.

[0023] The automatic control unit is connected to the instruments, valves and pumps of each unit, enabling automated interlocking operation of the entire process of concentrated sulfuric acid feeding, preparation, regeneration conveying and rinsing. This reduces human error, stabilizes regeneration conditions, lowers the operational safety risks caused by human intervention, and improves the overall operational stability of the system. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the system of the present invention; Figure 2 This is a flowchart of the regeneration process of the present invention. Detailed Implementation

[0025] This invention provides a technical solution; please refer to [link / reference]. Figure 1 and Figure 2This ion exchange resin regeneration system, which uses sulfuric acid instead of hydrochloric acid, includes: a sulfuric acid storage unit, a dilution and preparation unit, a regeneration and delivery unit, a resin regeneration tank, a waste liquid collection and treatment unit, and an automatic control unit. The sulfuric acid storage unit is a sealed concentrated sulfuric acid storage tank, equipped with monitoring components and leak-proof structures. The sulfuric acid delivery pipeline is made of sulfuric acid-resistant material, effectively preventing the volatilization and escape of concentrated sulfuric acid. Real-time monitoring of tank levels, temperature, and other operating statuses prevents leakage and spread risks, making it suitable for long-term storage and transportation of sulfuric acid media and reducing on-site operational safety hazards. The dilution and preparation unit connects to demineralized water and concentrated sulfuric acid and is equipped with online concentration detection components for preparing dilute sulfuric acid regeneration solution. Real-time closed-loop control of the reagent ratio ensures accurate and uniform regeneration solution concentration, avoiding localized excessive concentrations of concentrated acid that could lead to calcium sulfate scaling on the resin. The regeneration and conveying unit is equipped with an acid-resistant pump, flow and pressure monitoring components, and distribution components to uniformly deliver regenerated liquid to each regeneration tank. It can stably control the flow rate and pressure of the regenerated liquid, ensuring uniform contact of resin with the regenerated liquid in each tank and area, and improving the uniformity of resin regeneration throughout the tank. The waste liquid collection and treatment unit is equipped with pH monitoring and neutralization dosing components, and has a desulfurization system co-processing interface. It can pre-treat the sulfuric acid regeneration waste liquid with pH before connecting it to the existing desulfurization system of the power plant, realizing the harmless disposal of sulfate waste liquid, reducing wastewater treatment costs and environmental control pressure. The automatic control unit is connected to the instruments, valves, and pumps of each unit, enabling automated interlocking operation of the entire process of concentrated sulfuric acid feeding, dosing, conveying, regeneration, and rinsing, reducing human operation errors, and improving system operation stability and safety.

[0026] The dilution and preparation unit is a two-stage series gradient dilution and preparation mechanism. Along the medium flow direction, a first-stage static mixing and pre-dilution assembly and a second-stage metering tank homogenization and concentration assembly are sequentially arranged. The first-stage static mixing and pre-dilution assembly uses built-in flow-dispersing elements to ensure thorough turbulent mixing of concentrated sulfuric acid and demineralized water during flow, completing the initial coarse concentration adjustment and avoiding the problems of localized concentrated acid accumulation and uneven heat release during single-stage dilution. The second-stage metering tank has a built-in circulation homogenization pipeline and a high-precision online concentration detector for closed-loop correction of the concentrated sulfuric acid to demineralized water ratio. The circulation homogenization pipeline drives the liquid circulation within the tank, eliminating the phenomenon of concentration stratification at different concentration levels. The online concentration detector feeds real-time concentration data back to the automatic control unit, dynamically adjusting the feed ratio of concentrated sulfuric acid and demineralized water to achieve precise closed-loop control of the output regenerated solution concentration.

[0027] The distribution component of the regeneration delivery unit is a pressure-stabilizing and flow-throttling distribution assembly, including an inlet throttling orifice plate and a rear-end pressure-stabilizing buffer tank. The throttling orifice plate throttles and reduces the pressure of the incoming regenerated liquid at the inlet, while the pressure-stabilizing buffer tank reduces pressure pulsations from the acid-resistant pump, keeping the pressure in the main distribution pipe stable and providing a stable pressure basis for uniform liquid distribution in each branch pipe. Each output branch pipe is equipped with a flow regulating valve, which can independently control the regenerated liquid flow rate of a single branch pipe to adapt to the regeneration conditions of different tanks. In conjunction with the radial porous water distribution structure of the regeneration tank, the regenerated liquid is evenly distributed along the cross-section of the tank to the end face of the resin layer, avoiding flow deviation and short-circuit flow. The uniformity deviation of liquid distribution at the end face of the resin layer is ≤±5%, ensuring that the entire tank of resin can be evenly contacted with the regenerated liquid, avoiding problems such as insufficient local regeneration or excessively high local concentration that induces scaling.

[0028] The resin regeneration tank is equipped with a multi-point parameter monitoring component for the resin layer. Multiple sets of conductivity and ion concentration monitoring probes are arranged along the height of the resin layer, with the probes positioned at the top, middle, and bottom of the resin layer. This allows for real-time acquisition of data on the conductivity, sulfate concentration, and calcium ion concentration of the liquid phase within the resin layer at different heights. This provides a comprehensive understanding of the ion distribution and reaction process within the resin layer during regeneration. The automatic control unit incorporates a calcium sulfate scaling prediction interlock module. Based on real-time monitoring data, it calculates the calcium sulfate supersaturation. Using the calcium sulfate solubility product constant, current liquid phase ion concentration, and temperature parameters, it calculates the real-time supersaturation, quantitatively assessing the scaling risk at various locations within the resin layer. When the warning threshold is reached, the system automatically reduces the influent flow rate and concentration. By slowing down the ion replacement rate, it prevents sulfate and calcium ions from rapidly combining to form calcium sulfate crystals, thus achieving proactive prevention and control of scaling risks.

[0029] Pipelines and valves in the system that come into contact with concentrated and dilute sulfuric acid are all made of PTFE-lined fiberglass. These materials have excellent corrosion resistance to sulfuric acid media and can withstand the erosion of concentrated and dilute sulfuric acid for a long time, avoiding equipment leakage and damage caused by acid corrosion, extending equipment service life, and reducing maintenance frequency and operating costs. Instrument probes that come into contact with dilute sulfuric acid are made of Hastelloy, which ensures detection accuracy while having good resistance to dilute sulfuric acid corrosion, ensuring the long-term stability and operational reliability of monitoring data.

[0030] A regeneration process for ion exchange resins using sulfuric acid instead of hydrochloric acid, comprising the above-mentioned ion exchange resin regeneration system using sulfuric acid instead of hydrochloric acid, including: S1. Monitor effluent indicators and initiate regeneration after resin failure. By monitoring the conductivity, sodium ion, and hardness of the ion exchanger effluent online, accurately determine the state of resin exchange capacity depletion, avoiding premature regeneration that wastes reagents or delayed regeneration that affects effluent water quality.

[0031] S2. Backwash the resin layer with deionized water until the effluent is clear. The reverse water flow loosens the compacted resin layer, washes away suspended matter and broken resin particles adsorbed on the resin surface, and provides a uniform and loose resin layer structure for subsequent regeneration, improving the contact effect between the regenerated solution and the resin.

[0032] S3. Dilute concentrated sulfuric acid to prepare dilute sulfuric acid regeneration solution, adjust the ratio online, and accurately control the concentration of regeneration solution through gradient dilution to ensure stable and controllable concentration of regeneration agent to meet the needs of resin regeneration reaction.

[0033] S4. Resin regeneration is completed by introducing regenerating solution in stages and controlling the flow rate. By adjusting the concentration and flow rate of the influent in stages, the formation of calcium sulfate crystals is effectively suppressed while ensuring the depth of resin regeneration.

[0034] S5. Use demineralized water to replace and rinse the residual acid in the resin layer. The demineralized water will push the residual regeneration waste liquid and the displaced metal ions in the resin layer to be discharged, so as to avoid the residual acid and impurities affecting the quality of the subsequent effluent.

[0035] S6. After forward flushing until the water quality meets the standards, the system is put into operation. The high-flow forward flushing thoroughly removes the residual regenerated liquid and regenerated products in the resin layer, ensuring that the effluent water quality meets the operating standards of the power plant's water and steam system.

[0036] S7. Collect waste liquid, neutralize it, and discharge it into the desulfurization system for co-processing. Collect and treat acidic waste liquid generated throughout the regeneration process in a unified manner. Rely on the power plant's existing desulfurization system to achieve harmless disposal of sulfate and reduce environmental disposal costs.

[0037] Step S3 employs a two-stage gradient dilution process: the concentrated sulfuric acid is initially pre-diluted through static mixing in the first stage, and coarse dilution is rapidly completed using pipeline turbulence, dispersing the heat released during the dilution process and avoiding local overheating and sudden concentration changes. Then, it enters the second-stage metering tank for homogenization and concentration adjustment. Through circulation homogenization and closed-loop concentration control, precise fine-tuning is achieved to ensure a stable and uniform output regenerated solution concentration, resulting in a dilute sulfuric acid regenerated solution with a mass concentration of 2% to 4%. This concentration range is suitable for the kinetic requirements of the cation exchange resin regeneration reaction and can effectively control the liquid phase sulfate concentration level, reducing the risk of calcium sulfate scaling from the source.

[0038] Step S4 employs a concentration-flow-rate dual-gradient regeneration method: In the first stage, the resin layer is immersed in a low-flow-rate and low-concentration regenerator, accounting for 20%–30% of the total regeneration time. During this stage, the calcium ions adsorbed on the resin surface are slowly replaced, and the release rate of calcium ions on the resin surface and in the pores is controlled to prevent local sulfate ions from rapidly combining with calcium ions to form calcium sulfate crystals that adhere to the resin surface. In the second stage, the regenerator is increased to the set concentration and a stable flow rate for continuous regeneration. This stage ensures that the regenerator and resin are in full contact and react, deeply replacing the cations adsorbed inside the resin, and ensuring that the resin regeneration degree and working exchange capacity meet the operating requirements. When a local calcium sulfate supersaturation of ≥0.8 is detected, the inlet flow rate is automatically reduced by 10%–20%. By slowing down the ion exchange rate, the peak local ion concentration is reduced, actively eliminating the risk of scaling and balancing regeneration efficiency and anti-scaling effect.

[0039] In step S7, the waste liquid is pre-neutralized to pH 4-6 in the collection tank to adjust the acidic waste liquid to a pH range suitable for the desulfurization system influent, avoiding the impact of strong acid on the desulfurization system equipment, slurry microbial community, and absorption efficiency. Then, it is discharged into the power plant's desulfurization process water tank through the co-treatment interface. Sulfate reacts with the calcium-based absorbent in the desulfurization slurry to generate gypsum, which is discharged along with the desulfurization byproducts. The calcium-based absorbent in the power plant's existing desulfurization system is used to solidify sulfate, converting sulfate into a desulfurization gypsum byproduct that can be utilized by resources. There is no need to set up a separate deep sulfate treatment facility, realizing the resource-based disposal of waste liquid, significantly reducing the treatment cost of sulfate waste liquid and the environmental control pressure, while reducing the investment and land occupation of new wastewater treatment equipment.

[0040] The entire regeneration process is automatically executed by a PLC control system. It can complete the entire process—from failure detection, backwashing, reagent preparation, regeneration, displacement, forward washing, to commissioning—according to preset process parameters. This interlocking operation reduces manual intervention and improves the stability and consistency of the regeneration process. Furthermore, the PLC control system features fault alarms, parameter storage, and historical curve lookup functions. It can monitor abnormal parameters such as liquid level, concentration, pressure, and pH in real time and trigger audible and visual alarms, ensuring the inherent safety of sulfuric acid regeneration operations. The parameter storage and historical curve functions facilitate operators in reviewing the regeneration process, conducting process optimization, and performing fault tracing analysis. The regeneration parameters are adaptively adjusted according to the degree of resin failure, matching the corresponding regeneration dosage and duration to resins with different failure depths, saving reagent consumption while ensuring regeneration effectiveness.

Claims

1. An ion exchange resin regeneration system employing sulfuric acid in place of hydrochloric acid, comprising: The present invention comprises a sulfuric acid storage unit, a dilution and preparation unit, a regeneration and conveying unit, a resin regeneration tank, a waste liquid collection and treatment unit, and an automatic control unit, characterized in that: the sulfuric acid storage unit is a sealed concentrated sulfuric acid storage tank, equipped with monitoring components and a leak-proof structure; the sulfuric acid conveying pipeline is made of sulfuric acid-resistant material; the dilution and preparation unit is connected to demineralized water and concentrated sulfuric acid, and is equipped with an online concentration detection component for preparing dilute sulfuric acid regeneration solution; the regeneration and conveying unit is equipped with an acid-resistant pump, flow and pressure monitoring components, and a distribution component to uniformly deliver regeneration solution to each regeneration tank; the waste liquid collection and treatment unit is equipped with a pH monitoring and neutralization dosing component, and is provided with a desulfurization system co-processing interface; and the automatic control unit is connected to the instruments, valves, and pumps of each unit.

2. The ion exchange resin regeneration system employing sulfuric acid instead of hydrochloric acid as claimed in claim 1, wherein: The dilution and preparation unit is a two-stage serial gradient dilution and preparation mechanism. A first-stage pipeline static mixing and pre-dilution component and a second-stage metering box homogenization and concentration component are set sequentially along the medium flow direction. The second-stage metering box has a built-in circulation homogenization pipeline and a high-precision online concentration detector to perform closed-loop correction of the ratio of concentrated sulfuric acid and demineralized water.

3. The ion exchange resin regeneration system employing sulfuric acid instead of hydrochloric acid as claimed in claim 1, wherein: The distribution component of the regeneration conveying unit is a pressure-stabilizing and flow-throttling distribution component, which includes an inlet flow-throttling orifice plate and a rear pressure-stabilizing buffer tank. Each output branch pipe is equipped with a flow regulating valve. In conjunction with the radial porous water distribution structure of the regeneration tank, the uniformity deviation of the liquid distribution on the end face of the resin layer is ≤±5%.

4. The ion exchange resin regeneration system employing sulfuric acid instead of hydrochloric acid as claimed in claim 1, wherein: The resin regeneration tank is equipped with a multi-point parameter monitoring component for the resin layer, and multiple sets of conductivity and ion concentration monitoring probes are arranged along the height of the resin layer. The automatic control unit has a built-in calcium sulfate scaling prediction interlock module, which calculates the calcium sulfate supersaturation based on real-time monitoring data and automatically reduces the inlet flow rate and concentration when the warning threshold is reached.

5. The ion exchange resin regeneration system using sulfuric acid instead of hydrochloric acid according to claim 1, characterized in that: The pipelines and valves in the system that come into contact with concentrated sulfuric acid and dilute sulfuric acid are all made of PTFE-lined fiberglass, while the instrument probes that come into contact with dilute sulfuric acid are made of Hastelloy.

6. A regeneration process for ion exchange resins using sulfuric acid instead of hydrochloric acid, comprising the ion exchange resin regeneration system using sulfuric acid instead of hydrochloric acid as described in any one of claims 1-5, characterized in that, include: S1. Monitor the effluent indicators and start regeneration after determining that the resin has failed; S2. Backwash the resin bed with demineralized water until the effluent is clear; S3. Dilute concentrated sulfuric acid to prepare dilute sulfuric acid regeneration solution, and adjust the ratio online; S4. Regenerant is introduced in stages at a controlled rate to complete resin regeneration; S5. Demineralized water is used to replace and rinse the residual acid in the resin layer; S6. The system is put into operation after forward rinsing until the water quality meets the standards; S7. Waste liquid is collected, neutralized, and then discharged into the desulfurization system for co-treatment.

7. The regeneration process of the ion exchange resin using sulfuric acid instead of hydrochloric acid according to claim 6, characterized in that: Step S3 employs a two-stage gradient dilution process: concentrated sulfuric acid is initially pre-diluted through a first-stage static mixing process, and then homogenized and concentrated in a second-stage metering tank to prepare a dilute sulfuric acid regeneration solution with a mass concentration of 2% to 4%.

8. The regeneration process of the ion exchange resin using sulfuric acid instead of hydrochloric acid according to claim 6, characterized in that: Step S4 adopts a concentration-flow rate dual gradient regeneration method: in the first stage, the resin layer is wetted with low flow rate and low concentration regeneration solution, which accounts for 20% to 30% of the total regeneration time. In the second stage, the regeneration is increased to the set concentration and stable flow rate for continuous regeneration. When the local calcium sulfate supersaturation is detected to be ≥0.8, the inlet flow rate is automatically reduced by 10% to 20%.

9. The regeneration process of the ion exchange resin using sulfuric acid instead of hydrochloric acid according to claim 6, characterized in that: In step S7, the waste liquid is pre-neutralized to pH 4-6 in the collection tank, and then discharged into the power plant desulfurization process water tank through the co-processing interface. The sulfate ions react with the calcium-based absorbent in the desulfurization slurry to generate gypsum, which is discharged along with the desulfurization byproducts. There is no need to set up a separate deep sulfate treatment facility, thus realizing the resource-based treatment of waste liquid.

10. The regeneration process of the ion exchange resin using sulfuric acid instead of hydrochloric acid according to claim 6, characterized in that: The entire regeneration process is automatically executed by a PLC control system, which has functions such as fault alarm, storage of operating parameters and query of historical curves. The regeneration parameters are adaptively adjusted according to the degree of resin failure.

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