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CN-121974508-A - Method and system for preventing chlorine generation in amine liquid electrodialysis system

CN121974508ACN 121974508 ACN121974508 ACN 121974508ACN-121974508-A

Abstract

The invention relates to the technical field of flue gas carbon dioxide trapping and industrial water treatment, in particular to a method and a system for preventing chlorine generation in an amine liquid electrodialysis system. The method comprises the steps of deeply dechlorinating the amine liquid through an adsorption bed, and then purifying the amine liquid in an electrodialysis device, wherein the concentration of chloride ions in the amine liquid after deep dechlorination is less than 100 ppm. Through the full-chain technical scheme of source control, process blocking, terminal treatment and closed-loop monitoring, the multiple technical effects of chlorine risk prevention and control, equipment protection, energy efficiency improvement and automatic operation are realized.

Inventors

  • LIU XINGYI
  • ZHOU JINBO
  • ZHANG ZONGJIAN
  • LI ZHIQIANG

Assignees

  • 安徽海螺建材设计研究院有限责任公司

Dates

Publication Date
20260505
Application Date
20260114

Claims (10)

  1. 1. A method for preventing chlorine generation in an amine liquid electrodialysis system is characterized by comprising the steps of deeply dechlorinating an amine liquid through an adsorption bed and purifying the amine liquid in an electrodialysis device; the concentration of chloride ions in the amine liquid after deep dechlorination is less than 100 ppm.
  2. 2. The method of claim 1, wherein the anolyte of the electrodialysis device contains a reducing substance.
  3. 3. The method according to claim 1 or 2, wherein the exhaust port of the anode chamber of the electrodialysis device is connected to an alkali liquor absorption tower, the exhaust gas generated in the anode chamber is collected in a closed manner, and the exhaust gas is introduced into an alkaline absorption liquid for bubbling or spraying absorption treatment.
  4. 4. A method according to any one of claims 1-3, wherein the concentration of chloride ions in the amine solution after deep dechlorination is <50 ppm; the adsorption bed contains an adsorbent, wherein the adsorbent is amine-resistant functional anion exchange resin and/or chloride ion intercalated hydrotalcite; The amine-resistant liquid functional anion exchange resin is chloride ion exchange resin.
  5. 5. The method of claim 2, wherein the reducing substance is selected from one or more of sodium sulfite, sodium thiosulfate, and sodium bisulfite; The concentration of the reducing substance is 0.05-0.15 wt%.
  6. 6. The method of claim 3, wherein the alkaline absorption liquid is sodium hydroxide with a mass fraction of 5-15%.
  7. 7. A system for preventing chlorine generation in an amine liquid electrodialysis system is characterized by comprising a chloride ion adsorption module, a reducing agent adding module and a tail gas treatment module, wherein, The chloride ion adsorption module is arranged on a pipeline between the amine liquid supply unit and the electrodialysis device, and is an adsorption bed filled with a chloride ion selective adsorbent; The reducing agent adding module is communicated with an anolyte circulation pipeline of the electrodialysis device and comprises a reducing agent storage tank and a metering pump; The tail gas treatment module is connected with an exhaust port of an anode chamber of the electrodialysis device through a closed pipeline, and is an alkali liquor absorption tower filled with alkaline absorption liquid and used for bubbling or spraying absorption treatment of waste gas generated in the anode chamber.
  8. 8. The system of claim 7, wherein the chloride ion selective adsorbent is an amine-resistant functionalized anion exchange resin and/or chloride ion intercalated hydrotalcite; The functional anion exchange resin of the amine-resistant liquid is chloride ion exchange resin; the metering pump is a mechanical diaphragm metering pump and is used for adding the reducing substances in the reducing agent storage tank into the anode chamber circulation system according to a set proportion; the concentration of the reducing substance in the anode chamber circulation system is 0.05-0.15 wt%; the reducing substance is selected from one or more of sodium sulfite, sodium thiosulfate and sodium bisulphite; the alkaline absorption liquid is sodium hydroxide with the mass fraction of 5-15%.
  9. 9. The system of claim 7 or 8, further comprising a chloride ion concentration on-line monitor and a central control system; the chloride ion concentration on-line monitor is arranged on a pipeline of the chloride ion adsorption module, is used for monitoring the chloride ion concentration of the dechlorinated amine liquid in real time, and is in signal connection with the central control system; The central control system is respectively connected with the chloride ion concentration on-line monitor, the metering pump and the valve signal of the chloride ion adsorption module, and is used for receiving the chloride ion concentration monitoring data and controlling the dosing amount of the metering pump and the valve switching of the chloride ion adsorption module according to the monitoring data.
  10. 10. The system according to any one of claims 7-9, wherein the chloride ion adsorption module comprises at least two adsorption beds arranged in parallel, each adsorption bed is provided with a valve for controlling on-off of the adsorption bed, and the adsorption beds can be alternately switched for use; Preferably, the central control system receives real-time data transmitted by the chloride ion concentration on-line monitor, and when the chloride ion concentration is detected to be higher than 100ppm, the metering pump is automatically controlled to increase the addition amount of the reducing substance, and simultaneously an alarm signal is sent to prompt the switching of the adsorption beds of the chloride ion adsorption module.

Description

Method and system for preventing chlorine generation in amine liquid electrodialysis system Technical Field The invention relates to the technical field of flue gas carbon dioxide trapping and industrial water treatment, in particular to a method and a system for preventing chlorine generation in an amine liquid electrodialysis system. Background In the process of capturing carbon dioxide by a chemical absorption method, the absorbent amine liquid can be degraded and react with impurities (such as SO x、NOx、Cl-) in the flue gas to generate Heat Stability Salt (HSS) in the recycling process, SO that the activity of the amine liquid is reduced and the equipment corrosion is aggravated. Electrodialysis technology is an effective means of recovering amine solution, which uses an electric field to drive ions through a selective ion exchange membrane, thereby removing anions and cations in HSS. However, in actual operation, especially when treating carbon capture system amine solutions of chlorine-containing fumes of cement kilns and the like, irritating odors can occur around electrodialysis devices. This is due to the chloride ions (Cl -) carried in the amine solution, as a result of extensive analysis. In the anode compartment of electrodialysis, cl - is oxidized in preference to water to form toxic chlorine (Cl 2). The method not only forms a serious threat to the health of field operators, but also can lead chlorine to be dissolved in water to form hypochlorous acid, which can strongly corrode electrodialysis membranes, electrodes and peripheral equipment, shorten the service life of the device, and simultaneously reduce the current efficiency of the system through the side reaction. At present, when the electrodialysis is used for purifying amine liquid, the general attention is paid to the total salt removal rate, the safety and environmental hidden trouble caused by the side reaction of chloride ions are not realized, and a targeted solution is also lacking. The prior art simply operates the electrodialysis unit without knowledge of potential chlorine risk and without any methodological precautions. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides an amine liquid electrodialysis purification system and an amine liquid electrodialysis purification method capable of effectively preventing chlorine from generating and leaking, so that the problems of safety, corrosion and efficiency brought by the system and the method are fundamentally solved. In order to achieve the aim, the invention provides a method for preventing chlorine generation in an amine liquid electrodialysis system, which comprises the steps of deeply dechlorinating an amine liquid through an adsorption bed and purifying the amine liquid in an electrodialysis device; the concentration of chloride ions in the amine liquid after deep dechlorination is less than 100 ppm. Preferably, the anolyte of the electrodialysis device contains a reducing substance. Preferably, an exhaust port of an anode chamber of the electrodialysis device is connected to an alkali liquor absorption tower, waste gas generated in the anode chamber is collected in a sealing mode, and the waste gas is introduced into alkaline absorption liquid for bubbling or spraying absorption treatment. Preferably, the chloride ion concentration of the amine solution after deep dechlorination is less than 50 ppm. Preferably, the adsorbent bed contains an adsorbent, and the adsorbent is amine-resistant functionalized anion exchange resin and/or chloride ion intercalated hydrotalcite. Preferably, the amine-resistant functionalized anion exchange resin is a chloride ion exchange resin. Preferably, the reducing substance is selected from one or more of sodium sulfite, sodium thiosulfate and sodium bisulfite. Preferably, the concentration of the reducing substance is 0.05-0.15 wt%. Preferably, the alkaline absorption liquid is sodium hydroxide with the mass fraction of 5-15%. In a second aspect, the invention provides a system for preventing chlorine gas generation in an amine liquid electrodialysis system, the system comprising a chloride ion adsorption module, a reducing agent dosing module and a tail gas treatment module, wherein, The chloride ion adsorption module is arranged on a pipeline between the amine liquid supply unit and the electrodialysis device, and is an adsorption bed filled with a chloride ion selective adsorbent; The reducing agent adding module is communicated with an anolyte circulation pipeline of the electrodialysis device and comprises a reducing agent storage tank and a metering pump; The tail gas treatment module is connected with an exhaust port of an anode chamber of the electrodialysis device through a closed pipeline, and is an alkali liquor absorption tower filled with alkaline absorption liquid and used for bubbling or spraying absorption treatment of waste gas generated in the anode chamber. Preferably, the chlor