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CN-122010346-A - Treatment method and device for carbonate brine based on bipolar membrane electrodialysis

CN122010346ACN 122010346 ACN122010346 ACN 122010346ACN-122010346-A

Abstract

The invention discloses a method and a device for treating carbonate brine based on bipolar membrane electrodialysis, wherein the carbonate brine is added into a prepared low-concentration sodium metaaluminate solution through a chemical precipitation tank to carry out precipitation reaction, suspended matters are removed through a filter, organic matters are removed through an active carbon adsorption tower, and finally refined liquid is obtained through an ion exchange system; and (3) introducing the refined solution into a salt chamber of a treatment device, controlling the voltage to be 1.5-2.5V/membrane pair, circularly treating, respectively supplementing deionized water into an alkali chamber and an acid chamber, obtaining high-purity NaOH in the alkali chamber, and obtaining high-purity carbon dioxide in the acid chamber. The method realizes the efficient separation treatment of the carbonate brine, can effectively remove impurities to obtain high-purity NaOH and carbon dioxide, has low treatment energy consumption and controllable cost, and realizes the utilization of high-valued resources of the carbonate brine.

Inventors

  • ZHAO XIAOBIN
  • YOU GUIMING
  • XU WENXIAN
  • CHEN WEIQUN
  • CHENG XIANGWU
  • FAN WENCHAO

Assignees

  • 福建南平三元循环技术有限公司

Dates

Publication Date
20260512
Application Date
20260317

Claims (10)

  1. 1. A method for treating carbonate brine based on bipolar membrane electrodialysis, comprising: Delivering carbonate brine to a chemical precipitation tank, adding a low-concentration sodium metaaluminate solution for precipitation reaction, and removing calcium and magnesium ions to obtain refined solution A; delivering the refined solution A to a filter to remove suspended matters to obtain primary filtrate; Conveying the primary filtrate to an active carbon adsorption tower to remove organic matters and obtain a purified liquid; Conveying the purified liquid to an ion exchange system, and adopting Na-type cation exchange resins connected in series to carry out refining and purification to obtain refined liquid B; Continuously conveying the refined solution B to a salt chamber of a bipolar membrane electrodialysis device, starting a direct current power supply, controlling the voltage to be 1.5V/membrane pair to 2.5V/membrane pair, and enabling the solution in the salt chamber to circulate and reflux after the temperature of the solution in the salt chamber is controlled to be 30-45 ℃ through a plate heat exchanger; The deionized water is supplemented to an acid chamber of the bipolar membrane electrodialysis device, so that a solution in the acid chamber is circulated and refluxed, and carbon dioxide gas generated in the acid chamber is recovered; And replenishing deionized water to an alkali chamber of the bipolar membrane electrodialysis device, enabling solution in the alkali chamber to circulate and reflux after the temperature is controlled to be 30-45 ℃ by a plate heat exchanger, and when the concentration of NaOH solution reaches 5-15%, shunting part of the NaOH solution to an alkali liquid storage tank to obtain the NaOH solution.
  2. 2. The method for treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, wherein the refined solution B is continuously fed to a salt compartment of the bipolar membrane electrodialysis device, further comprising thereafter: and continuously circulating and refluxing the dilute brine with reduced concentration in the salt chamber to the salt chamber, mixing the dilute brine with the continuously conveyed refined solution B, and performing circulating electrolysis.
  3. 3. The method for treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, wherein said purified liquor is fed to an ion exchange system to obtain a purified liquor B, further comprising thereafter: delivering the refined solution B to an ultrafiltration system, and intercepting colloidal substances by adopting a microporous filter with the filtering precision not less than 0.5 mu m to obtain ultrafiltration refined solution; and conveying the ultrafiltration refined liquid to a salt chamber of the bipolar membrane electrodialysis device.
  4. 4. The method of treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, wherein the primary filtrate is fed to an activated carbon adsorption column, comprising: and conveying the primary filtrate to an adsorption tower filled with activated carbon at a hollow tower flow rate of 0.2-1.2 m/h, wherein the activated carbon is coconut shell-based granular carbon with a particle size of 1.0-3.0 mm and an iodine value of more than or equal to 800 mg/g.
  5. 5. The method for treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, wherein the activated carbon adsorption towers are operated in series by adopting double towers, and the total organic carbon value of final effluent is controlled to be less than 3mg/L.
  6. 6. The method for treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, wherein the step of replenishing deionized water to the acid compartment of the bipolar membrane electrodialysis device to circulate the solution in the acid compartment back comprises: And returning the circulating liquid of the acid chamber to the acid chamber after passing through a PP filter or a bag filter with the filtering precision not less than 5-10 mu m, and controlling the circulating current density of the acid chamber to be 400-1000A/m 2.
  7. 7. The method for treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, wherein the step of replenishing deionized water to the alkaline compartment of the bipolar membrane electrodialysis device to circulate the solution in the alkaline compartment back comprises: The circulating current density of the alkali chamber is controlled to be 400A/m <2 > -1000A/m <2 >.
  8. 8. The method of treating carbonate brine based on bipolar membrane electrodialysis according to claim 1, further comprising chemically washing the bipolar membrane electrodialysis device, comprising: conveying HCl solution with mass concentration of 2% -4% into the device for circular cleaning for 12 hours; pure water is conveyed into the device for circular cleaning for 12 hours; conveying NaOH solution with mass concentration of 2% -4% into the device for circular cleaning for 12 hours; Pure water was again supplied to the apparatus for cyclic washing for 12 hours.
  9. 9. A treatment plant for carbonate brine based on bipolar membrane electrodialysis, characterized in that it is adapted for use in the method according to any one of claims 1 to 8, said plant comprising: the salt chamber is used for containing and circulating the refined solution B; The alkali chamber is used for containing and circulating NaOH solution and is communicated with the alkali liquid storage tank; An acid chamber for generating and recovering carbon dioxide gas; The bipolar membrane stack comprises at least two bipolar membrane chambers connected in series, and each membrane chamber is provided with an inlet and an outlet which are communicated with the salt chamber, the alkali chamber and the acid chamber; the first circulating pipeline is connected with the outlet of the salt chamber and the inlet of the salt chamber of the bipolar membrane stack, and is sequentially provided with a first plate heat exchanger, a first pump body and a first filter along the material flow direction; The second circulating pipeline is connected with the outlet of the alkali chamber and the inlet of the alkali chamber of the bipolar membrane stack, and is sequentially provided with a second plate heat exchanger, a second pump body and a second filter along the material flow direction; and the third circulating pipeline is connected with the outlet of the acid chamber and the inlet of the acid chamber of the bipolar membrane stack, and a third pump body and a third filter are sequentially arranged on the third circulating pipeline along the material flow direction.
  10. 10. The processing apparatus according to claim 9, wherein the first filter, the second filter, and the third filter are precision filters, and the third filter is a PP filter or a bag filter, and the filtration accuracy is not lower than 5 μm to 10 μm.

Description

Treatment method and device for carbonate brine based on bipolar membrane electrodialysis Technical Field The invention relates to the field of chemical industry high-salt wastewater treatment, in particular to a method and a device for treating carbonate brine based on bipolar membrane electrodialysis. Background The traditional sodium hydroxide preparation method (such as chlor-alkali industry) and carbon dioxide capturing/converting process often have the problems of high energy consumption, associated byproducts (such as chlorine), complex process or secondary pollution. A process of converting carbonate brine (sodium carbonate or sodium bicarbonate) into sodium hydroxide and carbon dioxide. Many industrial processes, such as certain chemical industries, flue gas scrubbing, or processing in specific chemical fields, produce brine or wastewater rich in sodium carbonate and sodium bicarbonate. The sodium carbonate in the salt-containing wastewater is recycled and converted into sodium hydroxide with high value and high-purity carbon dioxide which can be recycled, so that the method has low carbon and circular economic benefits. The bipolar membrane electrodialysis technology can dissociate water molecules into H + and OH - at the interface layer of the bipolar membrane under the action of a direct current electric field, so that the salt solution is directly converted into corresponding acid and alkali without introducing new chemical substances. The technology has the advantages of relatively low energy consumption, clean and pollution-free process, compact device, adjustable product concentration and the like. Research shows that compared with sodium sulfate and other salts, sodium carbonate is used as a raw material to produce sodium hydroxide, high-purity alkali liquor can be obtained under similar conditions, and in an acid chamber of bipolar membrane electrodialysis under high current efficiency, H + and carbonic acid (CO 32-) are combined to generate carbonic acid (H 2CO3), and the carbonic acid is unstable and is easy to decompose to obtain high-purity carbon dioxide gas. The bipolar membrane electrodialysis system has high requirement on the purity of the feed liquid, and divalent or more metal ions such as calcium, magnesium and the like need to be effectively removed, so that the problem that pollutants form hydroxide precipitates in an alkali chamber to cause the blockage and pollution of the surface of a polluted membrane is avoided. The Bipolar Membrane Electrodialysis (BMED) is used as a novel membrane separation technology, can realize the directional migration of anions and cations through electric field driving, synchronously completes the salt decomposition (commonly used as Na 2SO4→H2SO4 plus NaOH) and the acid-base recovery in a single device, has the characteristics of low energy consumption, high efficiency, no phase change and environmental friendliness, and meets the requirements of green chemical industry and circular economy. Bipolar membrane electrodialysis (Bipolar Membrane Electrodialysis, BMED) is a membrane separation technology based on the electrodialysis principle, and utilizes bipolar membranes to dissociate water molecules into hydrogen ions (H +) and hydroxyl ions (OH -) and obtain acid and alkali, thereby realizing separation and conversion of salt solutions. The technology has the advantages of low energy consumption, simple and convenient operation, environmental protection and the like, and has remarkable advantages in the aspects of treating the salt-containing wastewater, recycling useful substances and the like. The bipolar membrane electrodialysis technology mainly has the problems of high equipment cost, short membrane pollution and service life, high energy consumption, low product concentration, complex pretreatment of wastewater and the like at present. Disclosure of Invention In view of the above, the present invention aims to provide a method and a device for treating carbonate brine based on bipolar membrane electrodialysis. In order to achieve the technical purpose, the invention adopts the following technical scheme: In a first aspect, the present invention provides a method for treating carbonate brine based on bipolar membrane electrodialysis, comprising: Delivering carbonate brine to a chemical precipitation tank, adding a low-concentration sodium metaaluminate solution for precipitation reaction, and removing calcium and magnesium ions to obtain refined solution A; Delivering the refined solution A to a filter to remove suspended matters to obtain primary filtrate; Conveying the primary filtrate to an active carbon adsorption tower to remove organic matters and obtain a purifying liquid; Conveying the purified liquid to an ion exchange system, and adopting Na-type cation exchange resins connected in series to carry out refining and purification to obtain refined liquid B; Continuously conveying the refined solution B to a salt chamber of a bipolar