WO2023050561A1 - 一种稳定运行的高硬水电化学除硬系统及处理工艺方法 - Google Patents

一种稳定运行的高硬水电化学除硬系统及处理工艺方法 Download PDF

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WO2023050561A1
WO2023050561A1 PCT/CN2021/134920 CN2021134920W WO2023050561A1 WO 2023050561 A1 WO2023050561 A1 WO 2023050561A1 CN 2021134920 W CN2021134920 W CN 2021134920W WO 2023050561 A1 WO2023050561 A1 WO 2023050561A1
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water
electrochemical
hard
diaphragm
hardness
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English (en)
French (fr)
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朱田震
姚光源
何爱珍
于德泽
陶蕾
王萌
滕厚开
秦立娟
张迪彦
刘建秋
赵新星
杨军
王宁
郝晓宇
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中海油天津化工研究设计院有限公司
中海油能源发展股份有限公司
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Publication of WO2023050561A1 publication Critical patent/WO2023050561A1/zh

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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/4602—Treatment of water, waste water, or sewage by electrochemical methods for prevention or elimination of deposits
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F2001/5218—Crystallization
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/46115—Electrolytic cell with membranes or diaphragms
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4612—Controlling or monitoring
    • C02F2201/46125—Electrical variables
    • C02F2201/4614—Current
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/005—Processes using a programmable logic controller [PLC]
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2301/00—General aspects of water treatment
    • C02F2301/04—Flow arrangements
    • C02F2301/043—Treatment of partial or bypass streams

Definitions

  • the invention relates to an efficient and stable electrochemical hardness removal method, which belongs to the field of electrochemical hardness removal.
  • Patent publications CN105523611A, CN106277369 B, CN204198498U, CN110615507 B, CN213558901 U, CN208594102U, CN204198498 U, CN 107235564 have been applied in engineering practice to a certain extent B).
  • electrochemical water softening technology can save the process of pre-adjusting alkali, adding acid to adjust the pH value, introducing new ions into the water without or as little as possible, less waste residue, and occupying a lot of space It has the advantages of small size, flexible operation, and convenient automatic control, and has high economic and environmental benefits.
  • electrochemical dehardening technology is that it can deposit and remove the scale-forming ions in water, so as to increase the concentration multiple and achieve the purpose of water saving. .
  • electrochemical dehardening technology mainly includes two types: direct electrochemical dehardening technology and diaphragm electrochemical dehardening technology.
  • the former mainly promotes calcium and magnesium ions to deposit on the cathode wall in the form of carbonate or hydroxide through the cathodic reaction at the cathode/water interface, and then through physical scraping (patent publication CN 213558901 U), chemical pickling or electrolysis Regularly clean the scale layer on the cathode wall surface by means of chemical inversion (patent publication CN 111170424 A), eliminate the voltage drop caused by the scale layer, and restore the activity of the electrode, so as to maintain a constant hard removal capacity and treatment energy consumption.
  • the diaphragm electrochemical dehardening technology adds an ion-conductive diaphragm between the cathode and anode to inhibit the neutralization of hydroxide ions and hydrogen ions generated by the cathode and anode, thereby improving the current efficiency.
  • the invention aims at the deficiencies in the existing membrane electrochemical dehardening technology, and provides a stably operating electrochemical dehardening method, which solves the problems of scale blockage in the electrolytic cell and poor operation stability during the operation of the device.
  • the present invention is a high-hardness electrochemical hard water removal system with stable operation, which includes an enhanced crystallization device and a scale crystal separation system connected in sequence, and also includes a diaphragm electrochemical hard removal device. It is characterized in that the water inlet of the enhanced crystallization device It is the water inlet of the high-hardness electrochemical hard removal system.
  • the alkaline softened water outlet of the scale crystal separation system is connected with a return pipe and a soft water outlet pipe, wherein the return pipe is connected with the water inlet of the diaphragm electrochemical hard removal device, and the soft water outlet
  • the water pipe is provided with an intersection connected with the anode outlet pipe of the diaphragm electrochemical dehardening device, so that the alkaline demineralized water flows downstream after being regulated by the anode outlet, and the cathode outlet water of the diaphragm electrochemical dehardening device passes through the cathode
  • the water outlet pipe of the chamber is connected with the water inlet pipe of the enhanced crystallization device, so that the outlet water of the cathode chamber is mixed with high-hard water and then enters the enhanced crystallization device.
  • the enhanced crystallization device is an electrochemical flocculation device, a chemical flocculation device, a seed crystallization device, a high-voltage electrostatic field enhanced crystallization device, an electromagnetic enhanced crystallization device or an ultrasonic enhanced crystallization device or a combination of several devices.
  • the scale separation system is a settling tank, a filter, or a combination of a settling tank and a filter, preferably a settling tank and a filter.
  • the diaphragm electrochemical dehardening device is a diaphragm electrolyzer, and the flow directions of the cathode chamber and the anode chamber are both bottom-in and top-out flow directions.
  • the anode material of the diaphragm electrochemical hard removal device is graphite, carbon felt, lead alloy, noble metal coating electrode, metal oxide coating electrode or conductive polymer coating electrode, preferably a metal oxide coating electrode;
  • the cathode material is Carbon steel, stainless steel, copper alloy, graphite, carbon felt, lead alloy, noble metal electrode, metal oxide coated electrode or conductive polymer coated electrode, preferably stainless steel or titanium alloy;
  • the diaphragm adopts ion exchange membrane, bipolar membrane, Microporous ceramic membrane, microporous plastic membrane, lignocellulosic membrane or asbestos membrane.
  • the system further includes a PLC automatic control system to realize close and remote control of process parameters.
  • the present invention also provides a process method for stably treating high-hard water by the above-mentioned high-hard water electrochemical hard-removal system, comprising the steps of:
  • the highly hard water is mixed with the cathode effluent of the above-mentioned diaphragm electrochemical hard removal device, and the pH value of the mixed water is controlled to be above 9.8, and then enters the enhanced crystallization device for crystallization and hard removal treatment to obtain scale-containing crystals with a total hardness of 0 to 2 mmol/L.
  • the alkaline demineralized water suspension containing scale crystals is introduced into the separation system for clarification treatment, and part of the obtained alkaline demineralized water flows back into the cathode chamber and anode chamber of the diaphragm electrochemical dehardening device for electrolytic treatment, and is controlled to enter the cathode chamber
  • the flow ratio to the anode chamber is 0.8-5, and the pH value of the cathode chamber outlet water is controlled between 10.5 and 13 by adjusting the electrolysis current, and the pH value of the anode chamber outlet water is controlled between 3.5 and 7.5;
  • the water from the cathode chamber of the diaphragm electrochemical hard removal device and the highly hard water are preferably mixed according to a flow ratio of 0.5 to 2.
  • the turbidity of the alkaline demineralized water after clarification treatment by the scale crystal separation system is less than 50 NTU.
  • the molar ratio of calcium hardness and inorganic carbon in the highly hard water is less than 0.8, add inorganic carbon to the highly hard water to adjust the molar ratio of calcium hardness to inorganic carbon in the range of 0.8 to 1.3.
  • the inorganic carbon mentioned therein is preferably carbon dioxide, water-soluble carbonate or bicarbonate.
  • water-soluble alkaline hydroxide is added to high hard water, preferably when the pH value of hard and soft water is less than 7, soluble alkaline hydroxide is added to high hard water.
  • the process method it is preferable to regularly clean the dirt and residue deposited inside the diaphragm electrochemical dehardening device, and it is more preferable to use pickling to clean it, and periodically pump the cleaning solution into the electrolytic cell through automatic control for cleaning.
  • the present invention further provides the application of the high-hardness water electrochemical dehardening system in the softening treatment of circulating cooling water, coal gasification black ash water and other scaling-prone water rich in calcium and magnesium hardness ions.
  • the beneficial effects of the high hard water electrochemical hard removal system and treatment method of the present invention are: by refluxing the treated alkaline demineralized water, the crystallization process in the diaphragm electrochemical hard removal device is transferred to the outside of the device, reducing the cost of the device. The risk of internal fouling and blockage is eliminated, the cleaning cycle is extended, and the efficient and stable operation of the diaphragm electrochemical dehardening device is realized.
  • Fig. 1 is a process flow chart of electrochemical hard removal according to an embodiment of the present invention.
  • Electrocoagulation enhanced crystallization device 1. Scale crystal separation system; 3. Diaphragm electrochemical hardening device; 101. Electrocoagulation anode; 102. Electrocoagulation cathode; 103. Electrocoagulation enhanced crystallization device power supply; 104.
  • High Hard water inlet pipe; 105 high hard water cathode water mixing pipe; 201, settling tank; 202, filter tank; 203, buffer tank; 204, return pipe; 205, soft water outlet pipe; 301, diaphragm electrochemical removal of hard cathode; 302, Cathode chamber; 303, diaphragm; 304, diaphragm electrochemical hard anode removal; 305, anode chamber; 306, diaphragm electrochemical hard removal power supply; 307, cathode chamber outlet pipe; 308, anode chamber outlet pipe; 309, cleaning tank.
  • the high-hardness water electrochemical dehardening system of the present invention includes an electrocoagulation enhanced crystallization device 1 , a scale crystal separation system 2 and a diaphragm electrochemical dehardening device 3 connected in sequence.
  • the water inlet of the electrocoagulation enhanced crystallization device 1 is the water inlet of the high-hardness electrochemical hard removal system
  • the alkaline softened water of the scale crystal separation system 2 flows through the buffer tank 203 and then flows through the return pipe 204 and the softened water outlet pipe 205 respectively
  • the return pipe 204 is connected with the water inlet of the diaphragm electrochemical hard removal device 3
  • the demineralized water outlet pipe 205 is provided with an intersection connected with the anode outlet pipe 308 of the diaphragm electrochemical hard removal device 3, so that the alkaline demineralized water passes through the anode
  • the outlet water from the chamber 305 is adjusted and then flows downstream for use.
  • the outlet water from the cathode chamber 302 of the diaphragm electrochemical dehardening device 3 communicates with the high-hard water cathode water mixing pipe 105 of the electrocoagulation enhanced crystallization device 1 through the cathode chamber outlet pipe 307, so that the cathode chamber 302 outlet water is mixed with high hard water (through the high hard water inlet pipe 104 ) and enters the electrocoagulation enhanced crystallization device 1 through the high hard water cathode water mixing pipe 105 .
  • Both the electrocoagulation anode 101 and the electrocoagulation cathode 102 are made of carbon steel.
  • the scale crystal separation system 2 is composed of a settling tank 201, a filter 202 and a buffer pool 203 connected in sequence, wherein the filtration precision of the filter is 1 ⁇ m.
  • the diaphragm electrochemical hard removal device 3 is a diaphragm electrolyzer.
  • the anode 301 is a titanium-based platinum group metal oxide coating electrode
  • the cathode 304 is a stainless steel electrode
  • the diaphragm 303 is a fluorine-containing sulfonic acid type cation exchange membrane.
  • the process method for the stable treatment of high hardness water by electrochemical hard water removal system includes the following steps:
  • the alkaline demineralized water suspension containing scale crystals enters the scale crystal separation system 2 for clarification treatment.
  • the alkaline demineralized water suspension containing scale crystals first enters the sedimentation tank 201, and after precipitation treatment, the supernatant is filtered through the filter 202 to obtain alkaline demineralized water with a turbidity below 10NTU, which further flows into Buffer tank 203, in which part of the alkaline demineralized water flows back into the cathode chamber 302 and anode chamber 305 of the diaphragm electrochemical dehardening device 3 through the return pipe 204 for electrolytic treatment.
  • Water from the cathode chamber 302 of the diaphragm electrochemical hard removal device 3 is mixed with high hardness water according to a flow ratio of 0.5 to 2.
  • sodium hydroxide is added to the high hard water to adjust the dehardened water out of the soft water outlet pipe 205 to more than 5.
  • the diaphragm electrochemical dehardening device 3 needs to regularly clean the deposited scale in the device, preferably pickling cleaning, and periodically pump the cleaning liquid in the cleaning tank 309 into the cathode chamber 302 and anode of the diaphragm electrochemical dehardening device 3 through the automatic control system In chamber 305, cycle cleaning is performed.
  • the above processing technology can be automatically controlled by PLC, and the near and remote control of each process parameter can be realized.
  • the beneficial effects of the present invention are: by refluxing the treated alkaline demineralized water, the crystallization process in the diaphragm electrochemical hard removal device is transferred to the outside of the device, reducing the risk of fouling and clogging inside the device, and prolonging the cleaning
  • the cycle realizes the purpose of efficient and stable operation of the diaphragm electrochemical dehardening device.
  • the present invention also has a certain removal effect on silicon in the treated water body, which can reduce the risk of downstream silicon scale deposition.
  • Table 1 shows the physical and chemical parameters of ash water quality in a coal chemical enterprise.
  • the gray water medium with a flow rate of 500L/h is drawn from the gray water tank, and the method of the present invention is used for softening treatment, and a long-term performance stability investigation is carried out.
  • the molar ratio of calcium hardness to total inorganic carbon is 3.54, far greater than 1, so sodium carbonate is added to the raw water to make the molar ratio of calcium hardness to total inorganic carbon close to 1.
  • the control parameters of the electrochemical hard removal process are shown in Table 2.
  • the effect of long-term operation is shown in Table 3.
  • the physical and chemical parameters of circulating cooling water in a refining and chemical enterprise are shown in Table 4.
  • the cooling water medium with a flow rate of 1000L/h is drawn from the cooling tower bypass, and the method of the present invention is used for softening treatment, and a long-term performance stability investigation is carried out.
  • the molar ratio of calcium hardness to total inorganic carbon is close to 1, so the high hardness water and the cathode chamber effluent are directly mixed for treatment.
  • the control parameters of the electrochemical hard removal process are shown in Table 5.
  • the effect of long-term operation is shown in Table 6.

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

本发明公开了一种稳定运行的高硬水电化学除硬系统及处理工艺方法。所述除硬系统包括依次连接的强化结晶装置(1)、垢晶分离系统(2)及隔膜电化学除硬装置(3)。所述处理工艺方法主要包括三步：1)高硬水与隔膜电化学除硬装置(3)阴极出水混合后经强化结晶装置(1)得到碱性软化水悬浊液；2)此悬浊液经垢晶分离系统(2)处理后部分回流进入隔膜电化学除硬装置(3)的阴极室(302)和阳极室(305)进行电解处理；3)隔膜电化学除硬装置阴极室(302)出水返回与高硬水混合进入强化结晶装置(1)，阳极室(305)出水则与剩余所述的碱性软化水混合流向下游。本发明通过将隔膜电化学除硬装置内的结晶过程转移到装置之外，降低了装置内部结垢堵塞风险，实现了隔膜电化学除硬装置高效稳定运行。

Description

一种稳定运行的高硬水电化学除硬系统及处理工艺方法 技术领域
本发明涉及一种高效稳定的电化学除硬方法，属于电化学除硬领域。
背景技术
利用电化学手段对含硬度离子的水体进行软化，早在1982年就有相关文献的报道(Technical Report-University of Texas.Centre for Research in Water Resources,CRWR 186,Austin(1982))，随后德国、以色列等国研究者开始将该技术用于含硬工业用水的软化处理研究(Chemical Engineering&Technology:Industrial Chemistry-Plant Equipment-Process Engineering-Biotechnology,1999,22(7):583-587；Desalination,2008,230(1-3):329-342；Journal of membrane science,2013,445:88-95；Desalination and Water Treatment,2011,31(1-3):35-41；Desalination and Water Treatment,2016,57(48-49):23147-23161)。自2002年起，该技术从以色列引入国内，相关文献及专利报道逐年增加(西安交通大学学报,2009,43(5):104；Separation and Purification Technology 2018,191:216-224；Separation and Purification Technology,2019,210:943-949.专利公开CN105523611A、CN106277369 B、CN204198498U、CN110615507 B、CN213558901 U、CN208594102U、CN204198498 U、CN 107235564 B)，目前该技术已在工程实践中得到一定程度的应用。相比于传统的石灰纯碱软化法，电化学软化水技术可省去预调碱、后加酸回调pH值过程、无需或尽可能少向水体中引入新的离子、废渣量少、占地空间小、操作灵活、便于自动化控制等优势，具有很高的经济效益和环境效益。此外，与以往传统的化学加药法以及电磁技术、超声波防垢技术相比，电化学除硬技术的优点在于能够将水中的成垢离子沉积取出，以此提升浓缩倍数，实现节水之目的。
目前，电化学除硬技术主要包括两种类型：直接电解除硬技术和隔膜电化学除硬技术。前者主要是通过阴极/水界面的阴极反应，促使钙、镁离子以碳酸盐或者氢氧化物形式在其阴极壁面沉积，然后通过物理刮除(专利公开CN 213558901 U)、化学酸洗或者电化学倒极(专利公开CN 111170424 A)等方式定期将阴极壁面垢层清理掉，消除垢层产生的电压降，恢复电极活性，以此保持恒定的除硬能力和处理能耗。目前，该类技术已广泛用在一些中小型水系统中。尽管如此，该技术电流效率低，一般在5％～25％之间，这极大限制了 该类型技术装备在大型水系统中的应用。与直接电解除硬技术不同的是，隔膜电化学除硬技术通过在阴阳极之间加一离子导电隔膜，抑制阴、阳极产生的氢氧根离子和氢离子中和，以此提升电流效率。相关文献及公开专利(Desalination,2010,263(1-3):285-289；CN 111170424 A，CN 107235564 B)表明，隔膜电化学除硬技术的电流效率可达到70％以上，除硬效果有显著的提高。此外，该技术所用电解电流密度相比前者技术可提升5倍以上，这两个优势可明显提升设备的集成度，降低设备占地面积，满足大型水系统的除硬需求。
目前针对隔膜电化学除硬，已有的文献(Desalination,2010,263(1-3):285-289)及公开专利(CN 107235564 B)主要采取的是“隔膜电化学除硬装置–晶种法诱导结晶–过滤”三步法处理工艺或者“隔膜法电化学除硬装置–沉淀”两步法处理工艺。这些处理工艺在均达到较高的除硬率，但其运行稳定性无法得到保证，这也是阻碍隔膜法电化学除硬技术应用的关键瓶颈之一。隔膜电化学除硬过程中，钙、镁垢会在阴极和隔膜壁面沉积，导致设备槽压快速升高，能耗增加，稳定运行周期不超过一天，通常只有几个小时，远达不到工程化应用要求；若采用周期性酸洗，耗酸量巨大，且产生大量高硬度含酸废水。对此问题，现有公开专利CN 106277369 B公开一种阻垢方法，阴极室使用非结垢性的导电水质，以避免阴极结垢堵塞的问题；利用阳极反应生成的酸来降低待处理水体中的碱度，以此降低下游结垢倾向。该专利一定程度上能保证电极及隔膜的稳定工作，但水体中的硬度离子并没有实质性地去除，为缓解设备腐蚀，实际工业用水的pH值(循环冷却水)往往会上调至8以上，该条件下碳酸盐碱度增加，结垢问题无法从本质上得到解决。
因此对隔膜电化学除硬技术来讲，如何在有效降低硬度的基础上保证装置运行的稳定性，仍亟需进一步改进现有技术。
发明内容
本发明针对现有隔膜电化学除硬技术存在的不足，提供一种稳定运行的电化学除硬方法，解决了装置运行过程中电解槽内结垢堵塞、运行稳定性差的问题。
本发明解决上述技术问题的技术方案如下：
本发明一种稳定运行的高硬水电化学除硬系统，包括依次连接的强化结晶装置和垢晶分离系统，还包括隔膜电化学除硬装置，其特征在于，所述的强化结晶装置的进水口为高硬电化学除硬系统入水口，垢晶分离系统的碱性软化水出水连接有回流管和软水出水管，其中回流管与所述的隔膜电化学除硬装置的进水口相连，软水出水管上设有与所述隔膜 电化学除硬装置的阳极出水管相通的交汇口，使碱性软化水经阳极出水调节后流向下游使用，所述的隔膜电化学除硬装置的阴极出水经阴极室出水管与强化结晶装置的进水管相通，使阴极室出水与高硬水混合后进入强化结晶装置。
所述的强化结晶装置为电化学絮凝装置、化学絮凝装置、晶种结晶装置、高压静电场强化结晶装置、电磁强化结晶装置或超声强化结晶装置的单个装置或者其中几种装置的组合。
所述垢晶分离系统为沉降槽、过滤器，或沉降槽与过滤器的组合，优选为沉降槽和过滤器的组合。
所述的隔膜电化学除硬装置为隔膜电解槽，其阴极室和阳极室流向均为下进上出流向。
所述隔膜电化学除硬装置的阳极材质为石墨、碳毡、铅合金、贵金属镀层电极、金属氧化物涂层电极或导电聚合物涂层电极，优选采用金属氧化物涂层电极；阴极材质采用碳钢、不锈钢、铜合金、石墨、碳毡、铅合金、贵金属电极、金属氧化物涂层电极或导电聚合物涂层电极，优选采用不锈钢或钛合金；隔膜采用离子交换膜、双极膜、微孔陶瓷膜、微孔塑料隔膜、木质纤维膜或石棉隔膜。
优选，所述的系统还包括PLC自动化控制系统，实现对工艺参数近、远程调控。
本发明还提供了上述高硬水电化学除硬系统稳定处理高硬水的工艺方法，包括步骤：
1)高硬水与所述的隔膜电化学除硬装置阴极出水混合，控制混合水pH值为9.8以上后进入强化结晶装置进行结晶除硬处理，得到总硬度在0到2mmol/L的含垢晶的碱性软化水悬浊液；
2)将含垢晶的碱性软化水悬浊液引入分离系统进行澄清处理，得到的碱性软化水部分回流进入隔膜电化学除硬装置的阴极室和阳极室进行电解处理，控制进入阴极室和阳极室的流量比在0.8～5，通过调节电解电流大小控制阴极室出水pH值在10.5到13之间，控制阳极室出水pH值在3.5到7.5之间；
3)隔膜电化学除硬装置阴极室出水返回与高硬水混合进入强化结晶装置，阳极室出水则与剩余所述的碱性软化水混合后得到除硬软水进入后续流程。
上述工艺方法中，所述隔膜电化学除硬装置阴极室出水和高硬水优选按照流量比0.5到2混合。
优选，所述垢晶分离系统澄清处理后的碱性软化水的浊度＜50NTU。
进一步优选，当高硬水中钙硬度和无机碳摩尔比例小于0.8时，向高硬水中补加无机碳，将钙硬度和无机碳摩尔比例调至0.8到1.3范围内。其中所述的无机碳优选为二氧化碳、可溶于水的碳酸盐或碳酸氢盐。
所述的工艺方法，根据除硬软水的pH值向高硬水中补加易溶于水的碱性氢氧化物，优选当除硬软水的pH值小于7时，向高硬水中补加易溶的碱性氢氧化物，将除硬软水pH值调至7以上。
所述的工艺方法，优选定期清洗所述的隔膜电化学除硬装置内部沉积的垢渣，进一步优选采用酸洗清理，通过自动控制周期性将清洗液泵入电解槽，进行清洗。
本发明还进一步提供了所述的高硬水电化学除硬系统在循环冷却水、煤气化黑灰水及其它富含钙、镁硬度离子的易结垢型水质等高硬水软化处理中的应用。
本发明高硬水电化学除硬系统及处理工艺方法的有益效果是：通过将处理后碱性软化水回流的方式，将隔膜电化学除硬装置内的结晶过程转移到装置之外，降低了装置内部结垢堵塞的风险，延长清洗周期，实现隔膜电化学除硬装置的高效稳定运行。
附图说明
图1为本发明的一种实施例电化学除硬工艺流程图。
其中，1、电絮凝强化结晶装置；2、垢晶分离系统；3、隔膜电化学除硬装置；101、电絮凝阳极；102、电絮凝阴极；103、电絮凝强化结晶装置电源；104、高硬水进水管；105、高硬水阴极水混合管；201、沉降槽；202、过滤罐；203、缓冲池；204、回流管；205、软水出水管；301、隔膜电化学除硬阴极；302、阴极室；303、隔膜；304、隔膜电化学除硬阳极；305、阳极室；306、隔膜电化学除硬电源；307、阴极室出水管；308、阳极室出水管；309、清洗罐。
具体实施方式
下面结合具体实施例对本发明一种稳定运行的高硬水电化学除硬系统及处理工艺方法做进一步描述。
如图1所示，本发明的高硬水电化学除硬系统按照流程包括依次连接的电絮凝强化结晶装置1、垢晶分离系统2及隔膜电化学除硬装置3。其中，电絮凝强化结晶装置1的进水口 为高硬电化学除硬系统入水口，垢晶分离系统2的碱性软化水经缓冲池203后分别流经回流管204和软化水出水管205，其中回流管204与隔膜电化学除硬装置3的进水口相连，软化水出水管205上设有与隔膜电化学除硬装置3的阳极出水管308相通的交汇口，使碱性软化水经阳极室305出水调节后流向下游使用，所述的隔膜电化学除硬装置3的阴极室302出水经阴极室出水管307与电絮凝强化结晶装置1的高硬水阴极水混合管105相通，使得阴极室302出水与高硬水(经高硬水进水管104)混合后经高硬水阴极水混合管105进入电絮凝强化结晶装置1。
电絮凝阳极101和电絮凝阴极102的材质均采用碳钢材质。
垢晶分离系统2由沉降槽201、过滤器202及缓冲池203依次连接组成，其中过滤器过滤精度为1μm。
隔膜电化学除硬装置3为隔膜电解槽。其阳极301采用钛基铂族金属氧化物涂层电极，阴极304采用不锈钢电极；隔膜303采用含氟磺酸型阳离子交换膜。
高硬水电化学除硬系统稳定处理高硬水的工艺方法包括如下步骤：
1)40～50℃的高硬水经高硬水进水管104与隔膜电化学除硬装置3阴极室302出水(经阴极水出水管307)混合进入高硬水阴极水进水管105，通过调节二者流量比，控制混合水pH值在9.8以上，然后进入电絮凝强化结晶装置1进行结晶除硬处理，得到总硬度在0到2mmol/L的含垢晶的碱性软化水悬浊液；
2)含垢晶的碱性软化水悬浊液进入垢晶分离系统2进行澄清处理。含垢晶的碱性软化水悬浊液先进入沉淀槽201，经沉淀处理后，上清液再经过滤器202过滤处理得到浊度在10NTU以下的碱性软化水，该碱性软化水进一步流入缓冲池203，其中部分碱性软化水经回流管204回流进入隔膜电化学除硬装置3的阴极室302和阳极室305进行电解处理。控制进入阴极室302和阳极室305的流量比在0.8～5，通过隔膜电化学除硬电源103调节电解电流大小，将阴极室302出水pH值控制在10.5到13之间，将阳极室305出水pH值控制在3.5到7.5之间；
3)隔膜电化学除硬装置3的阴极室302出水经阴极室出水管307返回与高硬水混合经高硬水阴极水混合管105进入电絮凝强化结晶装置1，阳极室305出水则与剩余所述的碱性软化水混合后得到除硬软水经软水出水管205进入后续流程。
隔膜电化学除硬装置3的阴极室302出水和高硬水按照流量比0.5到2的比例混合。
当高硬水中钙硬度和无机碳摩尔比例小于0.8时，向高硬水中补加碳酸钠，将钙硬度 和无机碳摩尔比例调至0.8到1.3范围内。
当除硬软水的pH值小于5时，向高硬水中补加氢氧化钠将软水出水管205出来的除硬软水调至5以上。
隔膜电化学除硬装置3需定期清洗装置内沉积垢渣，优选采用酸洗清理，通过自动控制系统周期性将清洗罐309中清洗液泵入隔膜电化学除硬装置3的阴极室302和阳极室305中，进行循环清洗。
以上处理工艺可通过PLC实现自动化控制，并实现各工艺参数的近、远程调控。
本发明的有益效果是：通过将处理后的碱性软化水回流的方式，将隔膜电化学除硬装置内的结晶过程转移到装置之外，降低了装置内部结垢堵塞的风险，并延长清洗周期，实现了隔膜电化学除硬装置高效稳定运行之目的。除此之外，本发明对处理水体的中的硅也具有一定的去除效果，可降低下游硅垢沉积的风险。
实施例1
某煤化工企业气化炉灰水水质物化参数见表1所示。从灰水槽引出500L/h流量的灰水介质，采用本发明方法进行软化处理，并进行长周期性能稳定性考察。从表1计算得到钙硬度与总无机碳的摩尔比为3.54，远大于1，故在原水中补加碳酸钠，使钙硬度与总无机碳的摩尔比接近1。电化学除硬工艺控制参数如表2所示。长周期运行效果如表3所示。
表1某煤化工企业气化炉灰水水质物化参数
Figure PCTCN2021134920-appb-000001
表2某煤化工企业气化炉灰水的电化学除硬工艺控制参数
Figure PCTCN2021134920-appb-000002
Figure PCTCN2021134920-appb-000003
表3某煤化工企业气化炉灰水的电化学除硬效果
Figure PCTCN2021134920-appb-000004
实施例2
某炼化企业循环冷却水水质物化参数见表4所示。从冷却塔旁路引出1000L/h流量的冷却水介质，采用本发明方法进行软化处理，并进行长周期性能稳定考察。从表1计算得到钙硬度与总无机碳的摩尔比接近1，故直接将高硬水和阴极室出水混合处理。电化学除硬工艺控制参数如表5所示。长周期运行效果如表6所示。
表4某炼化企业循环冷却水水质物化参数
Figure PCTCN2021134920-appb-000005
表5针对某炼化企业循环冷却水的除硬工艺参数
Figure PCTCN2021134920-appb-000006
表6针对某炼化企业循环冷却水的电化学除硬效果
Figure PCTCN2021134920-appb-000007
以上所述仅为本发明的较佳实施例，并不用以限制本发明，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (13)

  1. 一种稳定运行的高硬水电化学除硬系统，包括依次连接的强化结晶装置和垢晶分离系统，还包括隔膜电化学除硬装置，其特征在于，所述的强化结晶装置的进水口为高硬电化学除硬系统入水口，垢晶分离系统的软化水出水口连接有软化水回流管线和软化水出水管线，其中软化水回流管线与所述的隔膜电化学除硬装置的进水口相连，软化水出水管线上设有与所述的隔膜电化学除硬装置的阳极出水管线相通的交汇口，使软化水经阳极出水调节后回流向下游使用，所述的隔膜电化学除硬装置的阴极出水口经管线与强化结晶装置的进水管相通，使阴极出水与高硬水混合后进入强化结晶装置。
  2. 根据权利要求1所述的稳定运行的高硬水电化学除硬系统，其特征在于，所述的强化结晶装置为电化学絮凝装置、化学絮凝装置、晶种结晶装置、高压静电场强化结晶装置、电磁强化结晶装置或超声强化结晶装置的单个装置或者其中几种装置的组合。
  3. 根据权利要求1所述的稳定运行的高硬水电化学除硬系统，其特征在于，所述垢晶分离系统为沉降槽、过滤器，或沉降槽与过滤器的组合。
  4. 根据权利要求1所述的稳定运行的高硬水电化学除硬系统，其特征在于，所述的隔膜电化学除硬装置为隔膜电解槽，其中隔膜电解槽的阴极室和阳极室流向均为下进上出流向。
  5. 根据权利要求1所述的稳定运行的高硬水电化学除硬系统，其特征在于，所述隔膜电化学除硬装置的阳极材质为石墨、碳毡、铅合金、贵金属镀层电极、金属氧化物涂层电极或导电聚合物涂层电极；阴极材质采用碳钢、不锈钢、铜合金、石墨、碳毡、铅合金、贵金属电极、金属氧化物电极或导电聚合物涂层电极；隔膜为离子型交换膜、双极膜、微孔陶瓷膜、微孔塑料隔膜、木质纤维膜或石棉隔膜。
  6. 一种根据权利要求1所述的高硬水电化学除硬系统稳定处理高硬水的工艺方法，其特征在于，包括步骤：
    1)高硬水与所述的隔膜电化学除硬装置阴极出水混合，控制混合水pH值为9.8以上后进入强化结晶装置进行结晶除硬处理得到总硬度在0到2.0mmol/L的含垢晶的碱性软化水悬浊液；
    2)将含垢晶的碱性软化水悬浊液引入垢晶分离系统进行澄清处理，得到的碱性软化水部分回流进入隔膜电化学除硬装置的阴极室和阳极室进行电解处理，控制进入阴极室和阳极室的流量比在0.8～5，通过调节电解电流大小控制阴极室出水pH值在10.5到13之间，控制阳极室出水pH值在3.5到7.5之间；
    3)隔膜电化学除硬装置阴极室出水返回与高硬水混合进入强化结晶装置，阳极出水则与剩余所述的碱性软化水混合后得到除硬软水进入后续流程。
  7. 根据权利要求6所述的工艺方法，其特征在于，所述隔膜电化学除硬装置阴极室出水和高硬水按照流量比0.5～2混合。
  8. 根据权利要求6所述的工艺方法，其特征在于，所述垢晶分离系统澄清处理后的碱性软化水的浊度＜50NTU。
  9. 根据权利要求6所述的工艺方法，其特征在于，当高硬水中钙硬度和无机碳摩尔比例小于0.8时，向高硬水中补加无机碳，将钙硬度和无机碳摩尔比例调至0.8到1.3范围内；所述的无机碳优选为二氧化碳、可溶于水的碳酸盐或碳酸氢盐。
  10. 根据权利要求6所述的工艺方法，其特征在于，当除硬软水的pH值小于7时，向高硬水中补加易溶的碱性氢氧化物，使除硬软水pH值调至7以上。
  11. 根据权利要求6所述的工艺方法，其特征在于，所述的隔膜电化学除硬装置定期清洗装置内部沉积的垢渣。
  12. 根据权利要求1所述的稳定运行的高硬水电化学除硬系统，其特征在于，所述的系统还包括PLC自动化控制系统，实现对工艺参数近、远程调控。
  13. 一种权利要求1所述的高硬水电化学除硬系统在循环冷却水、煤气化黑灰水及其它富含钙、镁硬度离子的易结垢型水质的软化处理中的应用。
PCT/CN2021/134920 2021-09-30 2021-12-02 一种稳定运行的高硬水电化学除硬系统及处理工艺方法 WO2023050561A1 (zh)

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JP2009233503A (ja) * 2008-03-26 2009-10-15 Panasonic Corp 軟水化装置およびそれを用いた給湯装置
CN104211235A (zh) * 2014-09-30 2014-12-17 章明歅 一种电化学水垢去除装置及去除水垢的方法
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