Oxidation treatment process and treatment system for high-concentration chloride ion wastewater

Abstract

The invention provides a high-concentration chloride ion wastewater oxidation treatment process, which is used for a high-concentration chloride ion wastewater oxidation treatment system, and is characterized in that chloride ions are oxidized into chlorine gas by using an oxidation-reduction reaction method in an acid environment, and after the chlorine gas is blown out of a water body through aeration, the chlorine gas is absorbed by using an absorbent to generate available resources; the process comprises the following reactions: 2NaCl + Ca (ClO) 2 + 2H2SO4-> Na2SO4 + CaSO4 + 2H2O + Cl2 < superscript > (1) CaCl2 + Ca (ClO) 2 + 2H2SO4-> Ca2SO4 + 2H2O + 2Cl2 < superscript > (2) when the process is used for treating high-concentration chloride ion wastewater, secondary pollution is not generated, and the process has huge potential application in the field of high-concentration chloride ion wastewater.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wastewater treatment, in particular to a high-concentration chloride ion wastewater oxidation treatment process and system. BACKGROUND

[0002] High-concentration chloride ion wastewater often appears in the fields of power plant desulfurization wastewater, RO concentrated water of zero-emission plants, industrial circulating cooling water, etc. Traditional high-concentration chloride ion wastewater treatment methods generally include membrane concentrated water method, MVR evaporation method, multi-effect evaporation method, calcium aluminum ferrous salt method, and electrochemical method, etc. These methods generally have the following shortcomings: high cost of treatment equipment, high energy consumption in the treatment process, and many miscellaneous salts generated after treatment. SUMMARY

[0003] To solve the problems of the traditional high-concentration chloride ion wastewater treatment process, the present application provides a high-concentration chloride ion wastewater oxidation treatment process and system to solve the problems of high cost of treatment equipment and high energy consumption in the treatment process of traditional treatment methods.

[0004] To achieve the above-mentioned purpose, the present application provides a high-concentration chloride ion wastewater oxidation treatment process and system, which utilizes the redox reaction method in an acidic environment to oxidize chloride ions into chlorine gas, which is then absorbed by an absorbent after being blown out of the water body by aeration, producing a usable resource, and the specific reactions include the following: 2NaCl + Ca(ClO)2 + 2H2SO4→ Na2SO4 + CaSO4↓ + 2H2O + Cl2①

[0005] CaCl2 + Ca(ClO)2 + 2H2SO4→ Ca2SO4↓ + 2H2O + 2Cl2↑②.

[0006] Further, the process meets the following conditions when running:

[0007] (1) Measure the chloride ion concentration and convert it to molar concentration;

[0008] (2) Add concentrated sulfuric acid with a chloride ion concentration of 2-4 times to adjust the pH to 1-5;

[0009] (3) Add an oxidizing agent, calcium hypochlorite, with a chloride ion concentration of 0.8-1.2 times;

[0010] (4) The reaction temperature is maintained at 25-60℃;

[0011] (5) The stirring speed is 300-1500 rnd / m;

[0012] (6) The reaction time is 30-50 min.

[0013] Further, the high-concentration chloride ion wastewater oxidation treatment process is used for a high-concentration chloride ion wastewater oxidation treatment system, the system comprises a reactor, a sulfuric acid dosing tank, a calcium hypochlorite dosing tank, a waste gas washing device and a chimney, wherein the sulfuric acid dosing tank and the calcium hypochlorite dosing tank are connected with the reactor, the reactor is further connected with the waste gas device, and the waste gas washing device is connected with the chimney.

[0014] Further, the reactor comprises a reactor cavity, a high-concentration chloride ion wastewater inlet pipe, a support frame, a stirrer, an aeration system, a water outlet pipe, a demister and a chlorine-containing waste gas exhaust pipe.

[0015] Further, the stirrer is installed at the top of the reaction cavity and comprises a motor, a stirring rod and a stirring head, the motor is installed at the outer top of the reactor cavity, the stirring rod is inserted into the wastewater in the inside of the reaction cavity, and the stirring head is driven by the stirring rod to stir the wastewater after the motor is started.

[0016] Further, the aeration system comprises a Roots blower, an air pipe and an aeration head, the Roots blower is installed at a high position above the water level line outside the reactor cavity, is connected with the aeration head through the air pipe, and the aeration head is installed at the bottom of the reactor cavity.

[0017] Further, the chlorine-containing waste gas exhaust pipe is used for exhausting the aeration air and the chlorine gas generated by the reactor, is located at one side of the top of the reactor cavity, is connected with the reactor cavity, and is obliquely arranged at one end, so that the condensed water is beneficially backflowed.

[0018] Further, the waste gas washing device is selected to be a supergravity gas washing device.

[0019] The application has the beneficial effects that the application provides the high-concentration chloride ion wastewater oxidation treatment process and system, the treatment process utilizes the oxidation-reduction reaction method in an acidic environment to oxidize the chloride ions into chlorine gas, the chlorine gas is blown out of the water body after aeration, and then is absorbed by an absorbent to produce a usable resource, and the specific reactions include the following reactions:

[0020] 2NaCl + Ca(ClO)2 + 2H2SO4 → Na2SO4 + CaSO4↓ + 2H2O + Cl2 ①

[0021] CaCl2 + Ca(ClO)2 + 2H2SO4 → Ca2SO4↓ + 2H2O + 2Cl2↑ ②

[0022] When the process is used for treating the high-concentration chloride ion wastewater, the process has the advantages of small equipment investment, low treatment cost and no secondary pollution, and can be widely used in the field of treatment of the high-concentration chloride ion wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1The reactor structure schematic diagram described in the present application;

[0024] Figure 2 The concentration chloride ion wastewater oxidation treatment system schematic diagram described in the present application;

[0025] Legend: 1-reactor cavity 2-high concentration chloride ion wastewater inlet pipe 3-support frame 4-stirrer 5-aeration system 6-outlet pipe 7-demister 8-chlorine-containing waste gas discharge pipe 9-sulfuric acid dosing tank 10-calcium hypochlorite dosing tank 11-waste residue discharge port 12-gas washing device 13-chimney DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. It should be noted that similar reference numerals and letters in the following drawings represent similar items, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0027] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0028] Furthermore, the terms "horizontal", "vertical", and the like are used as terms of convenience to describe the general orientation of components, and do not require absolute horizontal or vertical orientations. For example, "horizontal" merely refers to a direction that is more horizontal than "vertical", and does not require that the structure be perfectly horizontal, but can be slightly inclined. In the description of the application, it is also necessary to note that unless otherwise explicitly specified and limited, the terms "arrange", "mount", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0029] Figure 1 For the reactor structure described in the application;

[0030] Figure 2 For the concentration of chloride ion wastewater oxidation treatment system described in the application;

[0031] The following will be combined with the Figure 1 And the Figure 2 The embodiments of the application are described.

[0032] The application provides a high-concentration chloride ion wastewater oxidation treatment process and treatment system, which utilizes the oxidation-reduction reaction method in an acidic environment to oxidize chloride ions into chlorine gas, which is then blown out of the water body by aeration and then absorbed by an absorbent to produce a usable resource, and specifically includes the following reactions: 2NaCl + Ca(ClO)2 + 2H2SO4 → Na2SO4 + CaSO4↓ + 2H2O + Cl2①

[0033] CaCl2 + Ca(ClO)2 + 2H2SO4 → Ca2SO4↓ + 2H2O + 2Cl2↑②.

[0034] Further, the process meets the following conditions when running:

[0035] (1) Measure the chloride ion concentration and convert it to molar concentration;

[0036] (2) Add concentrated sulfuric acid with a chloride ion concentration of 2-4 times to adjust the pH to 1-5;

[0037] (3) Add an oxidizing agent, calcium hypochlorite, with a chloride ion concentration of 0.8-1.2 times;

[0038] (4) The reaction temperature is maintained at 25-60℃;

[0039] (5) The stirring speed is 300-1500 rpm;

[0040] (6) The reaction time is 30-50 min.

[0041] Further, the high-concentration chloride ion wastewater oxidation treatment process is used for a high-concentration chloride ion wastewater oxidation treatment system, the system comprises a reactor, a sulfuric acid dosing tank, a calcium hypochlorite dosing tank, a waste gas washing device and a chimney, wherein the sulfuric acid dosing tank and the calcium hypochlorite dosing tank are connected with the reactor, the reactor is further connected with the waste gas device, and the waste gas washing device is connected with the chimney.

[0042] Further, the reactor comprises a reactor cavity, a high-concentration chloride ion wastewater inlet pipe, a support frame, a stirrer, an aeration system, a water outlet pipe, a demister and a chlorine-containing waste gas exhaust pipe.

[0043] Further, the stirrer is installed at the top of the reaction cavity and is composed of a motor, a stirring rod and a stirring head, the motor is installed at the outer top of the reactor cavity, the stirring rod is inserted into the wastewater inside the reaction cavity, and after the motor is started, the stirring head stirs the wastewater under the driving of the stirring rod.

[0044] Further, the aeration system is composed of a Roots blower, an air pipe and an aeration head, the Roots blower is installed above the water level of the reactor cavity, is connected with the aeration head through the air pipe, and the aeration head is installed at the bottom of the reactor cavity.

[0045] Further, the chlorine-containing waste gas exhaust pipe is used for exhausting the aeration air and the chlorine gas generated by the reactor, the chlorine-containing waste gas exhaust pipe is located at one side of the top of the reactor cavity, and the end connected with the reactor cavity is inclined, which is beneficial to the reflux of condensed water.

[0046] Further, the waste gas washing device selects a supergravity gas washing device.

[0047] Example 1

[0048] Taking high-concentration desulfurization wastewater as an example, the chloride ion concentration of the desulfurization wastewater of a certain thermal power plant is 20000 mg / L, 1.71 mol / L of concentrated sulfuric acid is added, PH=2, then 0.55 mol / L of calcium hypochlorite is added, and the mixture is stirred at 40℃ for 60 min, the aeration air volume is kept at 1000 m3 / h during the reaction, and the chloride ion concentration of the wastewater is measured to be 1836 mg / L after 60 min, which meets the treatment requirements. The treated water contains calcium sulfate and sodium sulfate and can be completely reused to configure calcium hydroxide desulfurization liquid.

[0049] Example 2

[0050] Take the RO concentrated water of a zero-emission steel plant as an example, a certain steel plant uses zero-emission technology to treat wastewater, but there is a problem of accumulation of chloride ion concentration, so after adding chemicals + microfiltration + ultrafiltration treatment of wastewater, the RO membrane concentration process is used to treat chloride ion. The chloride ion concentration of the RO membrane concentrated water is 1000 mg / L. 0.09 mol / L of concentrated sulfuric acid is added to the water, PH=5, then 0.028 mol / L of calcium hypochlorite is added, and the reaction is stirred at 30°C for 40 min. During the reaction process, the aeration air volume is maintained at 20000 m3 / h. After 40 minutes, the chloride ion concentration of the wastewater is measured to be 81 mg / L, meeting the treatment requirements. The treated water contains calcium sulfate, magnesium sulfate and sodium sulfate, and the corrosion is greatly reduced. After being treated by the original wastewater treatment process, it can be recycled.

[0051] Example 3

[0052] Take the circulating cooling water of a power plant as an example. The circulating cooling water of a certain power plant has a chloride ion concentration of 800 mg / L after multiple rounds of recycling. 0.07 mol / L of concentrated sulfuric acid is added to the water, PH=4, then 0.023 mol / L of sodium hypochlorite is added, and the reaction is stirred at 40°C for 50 min. During the reaction process, the aeration air volume is maintained at 10000 m3 / h. After 50 minutes, the chloride ion concentration of the wastewater is measured to be 71 mg / L, meeting the treatment requirements. The treated water contains calcium sulfate, magnesium sulfate and sodium sulfate, and the corrosion is greatly reduced. After being treated by the original hardening removal process, it can be recycled.

[0053] The present application provides a kind of concentration chloride ion wastewater oxidation treatment process and system, the treatment process utilizes the redox reaction method in acidic environment, chloride ion is oxidized into chlorine, after being blown out of water body by aeration, again using absorbent to absorb, produce usable resources, specifically including the following reactions:

[0054] 2NaCl+Ca(ClO)2+2H2SO4→Na2SO4+CaSO4↓+2H2O+Cl2(1)

[0055] CaCl2+Ca(ClO)2+2H2SO4→Ca2SO4↓+2H2O+2Cl2↑(2)

[0056] When the process treats high-concentration chloride ion wastewater, it has the advantages of small equipment investment, low treatment cost and no secondary pollution, and can be widely used in the field of treatment of high-concentration chloride ion wastewater.

Claims

1. A process for oxidizing high-concentration chloride ion wastewater, characterized in that: The aforementioned treatment process is used in a high-concentration chloride ion wastewater oxidation treatment system. The process utilizes an acidic environment and a redox reaction to oxidize chloride ions into chlorine gas. After being aerated and blown out of the water body, the gas is then absorbed by an absorbent to generate a usable resource. Specifically, the process includes the following reactions: 2NaCl+Ca(ClO)2+2H2SO4→Na2SO4+CaSO4↓+2H2O+Cl2① CaCl2+Ca(ClO)2+2H2SO4→Ca2SO4↓+2H2O+2Cl2↑②.

2. The high-concentration chloride ion wastewater oxidation treatment process according to claim 1, characterized in that: The process includes the following steps during operation: (1) Measure the chloride ion concentration and convert it to molar concentration; (2) Add concentrated sulfuric acid with a chloride ion concentration of 2-4 times to adjust the pH to 1-5; (3) Add calcium hypochlorite, an oxidant with a chloride ion concentration of 0.8-1.2 times; (4) The reaction temperature is maintained at 25-60℃; (5) The stirring speed is 300-1500 rnd / m; (6) The reaction time is 30-150 min.

3. The high-concentration chloride ion wastewater oxidation treatment process as described in claim 1 is used in a high-concentration chloride ion wastewater oxidation treatment system, characterized in that... The treatment system includes a reactor, a sulfuric acid dosing tank, a calcium hypochlorite dosing tank, an exhaust gas scrubbing device, and a chimney. The sulfuric acid dosing tank and the calcium hypochlorite dosing tank are connected to the reactor, the reactor is also connected to the exhaust gas scrubbing device, and the exhaust gas scrubbing device is connected to the chimney.

4. The high-concentration chloride ion wastewater oxidation treatment system as described in claim 3, characterized in that: The reactor includes a reactor chamber, a high-concentration chloride ion wastewater inlet pipe, a support frame, a stirrer, an aeration system, an outlet pipe, a demister, and a chlorine-containing waste gas exhaust pipe.

5. The high-concentration chloride ion wastewater oxidation treatment system according to claim 4, characterized in that: The high-concentration chloride ion wastewater inlet pipe is installed on the upper side of the reactor cavity, and the inlet inserted into the reactor cavity is below the water level line.

6. The high-concentration chloride ion wastewater oxidation treatment system according to claim 4, characterized in that: The agitator is installed at the top of the reactor cavity and consists of a motor, a stirring rod, and a stirring head. The motor is installed at the top of the reactor cavity, and the stirring rod is inserted into the wastewater inside the reactor cavity. After the motor is started, the stirring head stirs the wastewater under the action of the stirring rod.

7. The high-concentration chloride ion wastewater oxidation treatment system according to claim 4, characterized in that: The aeration system consists of a Roots blower, ductwork, and aeration heads. The Roots blower is fixed above the water level outside the reactor chamber and is connected to the aeration heads via ductwork. The aeration heads are installed at the bottom of the reactor chamber.

8. The high-concentration chloride ion wastewater oxidation treatment system according to claim 4, characterized in that: The outlet pipe is installed on the side of the reactor cavity opposite to the inlet pipe of the high-concentration chloride ion wastewater. The inlet of the outlet pipe is inserted into the reactor cavity below the water level line and is connected to the outlet pipe through a U-shaped bend.

9. The high-concentration chloride ion wastewater oxidation treatment system according to claim 4, characterized in that: The chlorine-containing exhaust pipe is used to discharge the aerated air and chlorine produced by the reactor. The chlorine-containing exhaust pipe is located on one side of the top of the reactor cavity, and the end connected to the reactor cavity is oriented at an angle to facilitate the return of condensate.

10. A high-concentration chloride ion wastewater oxidation treatment system according to claim 3, characterized in that: The waste gas scrubbing device is a supergravity scrubbing device.

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