Energy-saving dechlorinated light salt brine denitration device

Abstract

The utility model provides an energy-saving dechlorinated light salt brine denitration device which comprises an electric membrane stack, a direct current-to-alternating current inverter and a concentration device which are sequentially connected through lines. Reasonable concentration interval planning is adopted, reverse electrodialysis formed by a univalent ion exchange anion membrane and a cation exchange membrane forms a salinity difference power generation unit, ion separation and direct-current power generation can be realized while brine flows, the requirement of zero power consumption of dechlorinated light salt brine can be met, and system consumption is greatly saved; according to the device, reverse electrodialysis is used as power generation equipment, direct operation of power equipment can be realized by cooperating with an effective inversion power technology, resistance-type heating is used as a surplus power dissipation device, and stable operation of system power can be effectively realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to dechlorination weak brine sulfate radical denitration technical field, especially to a kind of energy-saving dechlorination weak brine denitration device. BACKGROUND

[0002] The salt water of all chlor-alkali enterprises is in a closed loop, and the added salt contains a certain amount of sulfate radical. If the sulfate radical in the salt water is not treated, the sulfate radical in the circulating salt water system will continue to increase, and too high sulfate radical will cause abnormal operation of ion-exchange membrane electrolytic cell.

[0003] Dechlorination weak brine is the tank liquid of sodium hydroxide produced by ion-exchange membrane in chlor-alkali enterprises, which contains 200 g / L of sodium chloride and 10 g / L of sodium sulfate. In the traditional technology, the dechlorination weak brine is led out, and then the sulfate radical is concentrated, and then the crystallization conversion of sulfate radical is realized, and the solid sulfate is discharged from the salt water system. The mainstream sulfate radical concentration technology at present is to separate the sulfate radical and sodium chloride by using nanofiltration membrane.

[0004] Nanofiltration membrane is a pressure-driven membrane. Under the action of pressure difference driving force, sodium chloride salt and small molecules of water permeate the nanofiltration membrane, and large molecules of sulfate radical are intercepted on the membrane surface. In this way, the raw material liquid can be separated into two outflow liquids, one is the permeate liquid with low sulfate radical concentration, and the other is the concentrated liquid with high sulfate radical concentration. Although the specific separation devices are different, in order to complete the concentration process, the raw water needs to be pressurized. At present, centrifugal water pump or volumetric water pump is used to complete the pressurization process of dechlorination weak brine. In order to concentrate the sulfate radical to about 60-80 g / L, the pressurization pressure of the selected water pump needs to reach more than 2 MPa. If it is required to reach more than 130 g / L, the pressurization pressure of the selected water pump needs to reach more than 4 MPa.

[0005] For a 400,000-ton chlor-alkali enterprise, when the wet salt adopts 96% sodium chloride content and the salt index of sulfate radical is 0.55%, the flow rate of dechlorination weak brine that needs to be concentrated is about 110 m3 / h. According to the pressure of 2 MPa, the motor type of the pump needs to be selected to about 110 kW.

[0006] The dechlorination dilute brine sulfate concentration device is a hardware device relying on a water pump, and the water pump is a typical energy consumption unit, which is generally driven by 50Hz three-phase alternating current. In other words, regardless of how to operate, the dechlorination dilute brine sulfate concentration device needs to draw external electric energy as a basic consumption for operation. Generally, at least 1kW / m3 of energy consumption level is needed. Chlor-alkali enterprises are energy consumers, and the comprehensive power consumption index is a crucial process technical parameter for the enterprise. If the energy consumption level of the process unit is reduced, the cost of the enterprise will be reduced, and the competitiveness of the enterprise will be improved.

[0007] Therefore, an energy-saving dechlorination dilute brine denitration device is provided to solve the problem of high energy consumption of the dechlorination dilute brine denitration in the prior art. Content of the utility model

[0008] In view of the above-mentioned defects of the prior art, the purpose of the utility model is to provide an energy-saving dechlorination dilute brine denitration device for solving the problem of high energy consumption of the dechlorination dilute brine denitration in the prior art.

[0009] To achieve the above-mentioned purpose and other related purposes, the utility model provides an energy-saving dechlorination dilute brine denitration device, which comprises an electric membrane stack, a direct-current to alternating-current inverter and a concentration device, and the electric membrane stack, the direct-current to alternating-current inverter and the concentration device are connected in sequence through a circuit.

[0010] The electric membrane stack is used to generate direct current and is delivered to the direct-current to alternating-current inverter, and the direct-current to alternating-current inverter is used to convert the direct current into alternating current to supply energy to the concentration device.

[0011] Preferably, the inside of the electric membrane stack is sequentially provided with an anode chamber, a dilution chamber and a cathode chamber from left to right, and concentration chambers are further arranged on both sides of the dilution chamber.

[0012] The dilution chamber and the two concentration chambers are provided with a plurality of interval arranged cation exchange membranes and anion exchange membranes.

[0013] Preferably, five input ends and five output ends are arranged on the front and back sides of the electric membrane stack respectively, and the five input ends and the five output ends correspond to the anode chamber, the dilution chamber, the cathode chamber and the two concentration chambers of the electric membrane stack respectively.

[0014] Preferably, a positive electrode electrode and a negative electrode electrode are arranged on the two sides of the electric membrane stack respectively, and the positive electrode electrode and the negative electrode electrode are connected with the direct-current to alternating-current inverter through wires.

[0015] Preferably, the anion exchange membrane can be used for monovalent ion separation, and the separation coefficient of chloride ions and sulfate radicals can reach below 0.01.

[0016] Preferably, the concentration device comprises a pressure supply pump one, a nanofiltration membrane assembly one, a pressure supply pump two, a nanofiltration membrane assembly two, a material separation and concentration device, and a heating device.

[0017] One output end of the electric membrane stack is connected with the input end of the pressure supply pump one through a pipeline, and the output end of the pressure supply pump one is connected with the input end of the nanofiltration membrane assembly one through a pipeline.

[0018] The other output end of the electric membrane stack is connected with the input end of the pressure supply pump two through a pipeline, and the output end of the pressure supply pump two is connected with the input end of the nanofiltration membrane assembly two through a pipeline.

[0019] The output pipelines of the nanofiltration membrane assembly one and the nanofiltration membrane assembly two are combined and connected with the input end of the material separation and concentration device, and one output end of the material separation and concentration device is connected with the input end of the heating device.

[0020] Preferably, the other output pipeline of the nanofiltration membrane assembly two is combined with the other output pipeline of the material separation and concentration device and connected with one input end of the electric membrane stack.

[0021] Preferably, the direct-current-to-alternate-current inverter is connected with the pressure supply pump one, the pressure supply pump two, the material separation and concentration device, and the heating device through lines for energy supply operation.

[0022] As described above, the energy-saving dechlorination and denitration device for dilute salt water has the following beneficial effects: the device adopts reasonable concentration interval planning, a reverse electrodialysis unit composed of a single ion exchange negative membrane and a cation exchange membrane, and realizes ion separation and direct current power generation while salt water flows, can realize the demand of zero power consumption of dechlorination and dilute salt water, greatly saves system consumption; the device takes reverse electrodialysis as a power generation equipment, and cooperates with effective inverter technology to realize direct operation of a power equipment, takes a resistance type heating as a redundant power dissipation device, and can effectively realize stable operation of system power. The device changes the idea, changes the energy consumption device into a power generation device, and opens up a new vision for comprehensive utilization of the same type of high-concentration salt water.

[0023] Therefore, the device effectively overcomes various shortcomings in the prior art and has high industrial utilization value. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 A structure schematic view of the energy-saving dechlorination and denitration device for dilute salt water is shown.

[0025] Fig. 2 An electric membrane stack structure view of the energy-saving dechlorination and denitration device for dilute salt water is shown.

[0026] ELEMENT NUMBER EXPLANATION

[0027] 1. electric membrane stack; 2. pressure pump 1; 3. nanofiltration membrane module 1; 4. pressure pump 2; 5. nanofiltration membrane module 2; 6. material separation and concentration device; 7. heating device; 9. DC to AC inverter;

[0028] 10. anode chamber; 11. dilution chamber; 12. cathode chamber; 13. concentration chamber; 14. cation exchange membrane; 15. anion exchange membrane. DETAILED DESCRIPTION

[0029] The following specific embodiments illustrate the implementation of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification.

[0030] Please refer to Figs. 1-2 . It should be understood that the structure, proportion, size, etc. shown in the drawings attached to the specification are only used to understand and read the content disclosed in the specification for those skilled in the art, and are not used to limit the implementation conditions of the present application, so they do not have technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application. At the same time, the terms such as "up", "down", "left", "right", "middle" and "one" used in the specification are only for the convenience of clear description, and are not used to limit the scope of the present application, and the change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the scope of the present application.

[0031] The arrow direction in the drawing of the specification is the solution flow direction.

[0032] As Figs. 1-2 shown, the present application provides an energy-saving dechlorination and desalination device, which comprises an electric membrane stack 1, a DC to AC inverter 9 and a concentration device, and the electric membrane stack 1, the DC to AC inverter 9 and the concentration device are connected in sequence through a line. The electric membrane stack 1 is used to generate direct current, which is delivered to the DC to AC inverter 9, and the DC to AC inverter 9 is used to convert the direct current into alternating current to power the concentration device. In use, the dechlorinated and desalinated water is introduced into the electric membrane stack 1, and the electric membrane stack 1 will exhibit reverse electrodialysis phenomenon under the action of natural seepage, thereby generating direct current, which is delivered to the DC to AC inverter 9 through a line, realizing the phase change conversion of electric current and the adjustment of voltage to ensure the output of stable industrial electricity of 380V, meeting the power operation needs of the concentration device in the system.

[0033] In an embodiment, please refer to Figs. 1-2, the inside of the electric membrane stack 1 is sequentially distributed with the anode chamber 10, the dilution chamber 11 and the cathode chamber 12 from left to right, and the dilution chamber 11 is further provided with the concentration chambers 13 on both sides; the dilution chamber 11 and the two concentration chambers 13 are provided with a plurality of spaced cation exchange membranes 14 and anion exchange membranes 15. In use, the anode chamber 10 is connected with 2mol / L-10mol / L sodium hydroxide solution, the cathode chamber 12 is connected with hydrochloric acid solution, the dilution chamber 11 is connected with dechlorinated dilute brine solution, and the concentration chambers 13 are connected with 0.1-0.5mol / L NaCl dilute brine. Preferably, the concentration of the sodium hydroxide solution is maintained at 2mol / L-10mol / L, the concentration of the hydrochloric acid solution is maintained at 2mol / L-10mol / L, the dechlorinated dilute brine after the electric membrane stack 1 is reduced to become dilute liquid, i.e. a solution containing lower sodium chloride concentration and certain sodium sulfate concentration, and the sodium chloride concentration of the NaCl dilute brine is increased to become concentrated liquid, i.e. a solution containing certain sodium chloride concentration and very little sodium sulfate concentration; preferably, the solutions on the sides of the dilution chamber and the concentration chambers adopt countercurrent mode, and the concentration difference on both sides is maintained above 20g / L. Typically, the sodium chloride concentration of the dechlorinated dilute brine is 200-210g / L, the sodium sulfate concentration is 8-12g / L, the sodium chloride concentration of the solution after dilution is 100-150g / L, and the sodium sulfate concentration is 8-12g / L. The sodium chloride concentration of the solution after concentration is 30-60g / L, and the sodium sulfate concentration is 0-0.5g / L.

[0034] In an embodiment, referring to Figs. 1-2 , the electric membrane stack 1 is provided with five input ends and five output ends on both sides, and the five input ends and the five output ends correspond to the anode chamber 10, the dilution chamber 11, the cathode chamber 12 and the two concentration chambers 13 of the electric membrane stack 1. In the anode chamber 10, the hydroxyl ions will undergo electrolytic oxidation reaction to produce oxygen. In the cathode chamber 12, the hydrogen ions will undergo electrolytic reduction reaction to produce hydrogen.

[0035] In an embodiment, referring to Figs. 1-2 , the electric membrane stack 1 is provided with positive electrode and negative electrode on both sides, and the positive electrode and the negative electrode are connected with the direct current to alternating current inverter 9 through wires. According to the actual use, the electrode pair with appropriate specification can be selected to output 300V-700V direct current.

[0036] In an embodiment, referring to Figs. 1-2 , the anion exchange membrane 15 can be used for monovalent ion separation, and the separation coefficient of chloride ions and sulfate radicals can reach below 0.01.

[0037] In an embodiment, referring to Figs. 1-2, the concentrating device comprises a pressure pump 2, a nanofiltration membrane assembly 3, a pressure pump 4, a nanofiltration membrane assembly 5, a material separation and concentration device 6, and a heating device 7; one output end of the electric membrane stack 1 is connected with the input end of the pressure pump 2 through a pipeline, the output end of the pressure pump 2 is connected with the input end of the nanofiltration membrane assembly 3 through a pipeline; the other output end of the electric membrane stack 1 is connected with the input end of the pressure pump 4 through a pipeline, the output end of the pressure pump 4 is connected with the input end of the nanofiltration membrane assembly 5 through a pipeline; the output pipelines of the nanofiltration membrane assembly 3 and the nanofiltration membrane assembly 5 are combined and connected with the input end of the material separation and concentration device 6, and one output end of the material separation and concentration device 6 is connected with the input end of the heating device 7. In use, the dechlorinated dilute brine is introduced into the dilution chamber 11 to reduce the concentration of sodium chloride and be converted into dilute liquid with a sodium chloride concentration of 100-150 g / L and a sodium sulfate concentration of 8-12 g / L, and then flows through the pressure pump 2 and the nanofiltration membrane assembly 3 to concentrate the sulfate concentration and be converted into two solutions, one of which is dechlorinated dilute brine concentrate with a sodium chloride concentration of 100-150 g / L and a sodium sulfate concentration of 60-200 g / L, which is equivalent to the concentrate of the traditional dechlorinated dilute brine concentrating device, and the other is nanofiltration permeate with a sodium chloride concentration of 100-160 g / L and a sodium sulfate concentration of 0.5-2 g / L. The concentrating chamber 13 outputs a solution with a sodium chloride concentration of 30-60 g / L and a sodium sulfate concentration of 0-0.5 g / L, which flows through the pressure pump 4 and the nanofiltration membrane assembly 5 and is divided into two solutions, one of which is combined with the nanofiltration permeate described above and then enters the material separation and concentration device 6, and the other is combined with the nanofiltration permeate described above and then enters the material separation and concentration device 6. The material separation and concentration device 6 separates and concentrates the solution to be converted into two solutions, one of which is separation lean liquid with a sodium chloride concentration of 0-2 g / L and a sodium sulfate concentration of 0-0.1 g / L, and the other is concentrate with a sodium chloride concentration of 190-220 g / L and a sodium sulfate concentration of 2-5 g / L. The concentrate with a sodium chloride concentration of 190-220 g / L and a sodium sulfate concentration of 2-5 g / L is converted into permeate equivalent to the traditional dechlorinated dilute brine concentrating device after entering the heating device and is sent out to enter the brine system.

[0038] In an embodiment, please refer to Figs. 1-2 , the other output pipeline of the nanofiltration membrane assembly 5 is combined with the other output pipeline of the material separation and concentration device 6 and then connected with one input end of the electric membrane stack 1. The separation lean liquid is combined with the other solution with a low sodium chloride concentration discharged from the nanofiltration membrane assembly 5 and then is sent into the electric membrane stack 1 as make-up water of the NaCl dilute brine.

[0039] In an embodiment, please refer to Figs. 1-2 , the direct current to alternating current inverter 9 is connected with the pressure pump 2, the pressure pump 4, the material separation and concentration device 6, and the heating device 7 through lines respectively for energy supply operation.

[0040] The material concentration device 6 can include: a, a reverse osmosis device including a reverse osmosis membrane shell and elements, a pressure supply pump (electrically driven), for realizing material separation by using electricity to change one solution into two solutions, i.e. dilute liquid and concentrated liquid; b, a MVR evaporation device including an evaporation chamber, a heating chamber, and an electrically driven MVR compressor, for realizing material separation by using electricity to change one solution into dilute liquid and concentrated liquid; c, an electrodialysis device including an electrodialysis membrane stack, a driving power supply, and a pressure supply pump (electrically driven), for realizing material separation by using electricity to change one solution into dilute liquid and concentrated liquid. The heating device 7 can be an electric resistance water heater, which realizes water heating by electric heating.

[0041] The pressure supply pump one 2, the pressure supply pump two 4, the material separation and concentration device 6, and the heating device 7 are all electrically driven devices, and after the above-mentioned electric membrane stack 1, an electric power of 3809.8 kW can be generated; after inversion, the effective output power is 3543.2 kW, the power required by the pressure supply pump one 2 is 272.5 kW, the power required by the pressure supply pump two 4 is 626.7 kW, and the power required by the material separation and concentration device 6 is 2467.3 kW. The total power required is 3366.5 kW. The self-produced and consumed residual power of the system is 176.7 kW. The heating device 7 can realize the temperature rise of the overflow solution by 3.2℃. The consumption of hydrochloric acid and sodium hydroxide is 9.4 mol / h.

[0042] The above-mentioned embodiments only exemplarily illustrate the principle and effect of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. An energy-saving dechlorinated dilute brine denitration device, characterized in that, include: An electro-film stack (1), a DC-to-AC inverter (9), and a concentration device are connected in sequence via lines. The electrofilm stack (1) is used to generate direct current and deliver it to the DC-to-AC inverter (9), which is used to convert the direct current into AC power to power the concentration device.

2. The energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 1, wherein: The interior of the electrofilm stack (1) is provided with an anode chamber (10), a desalination chamber (11) and a cathode chamber (12) arranged from left to right. Concentration chambers (13) are also provided on both sides of the desalination chamber (11). The desalination chamber (11) and the two concentration chambers (13) are equipped with a number of cation exchange membranes (14) and anion exchange membranes (15) arranged at intervals.

3. The energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 2, wherein: The electrofilm stack (1) is provided with five input terminals and five output terminals on the front and rear sides respectively. The five input terminals and five output terminals correspond to the anode chamber (10), desalination chamber (11), cathode chamber (12) and two concentration chambers (13) of the electrofilm stack (1) respectively.

4. The energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 1, wherein: The electrofilm stack (1) is provided with a positive electrode and a cathode electrode on both sides, and the positive electrode and the cathode electrode are connected to the DC to AC inverter (9) through wires.

5. The energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 2, wherein: The anion exchange membrane (15) can be used for monovalent ion separation, and its separation coefficient for chloride and sulfate ions can reach below 0.

01.

6. An energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 1, wherein: The concentration device includes a pressure pump (2), a nanofiltration membrane module (3), a pressure pump (4), a nanofiltration membrane module (5), a material separation and concentration device (6), and a heating device (7); One output end of the electrofiltration membrane stack (1) is connected to the input end of the pressure pump (2) through a pipeline, and the output end of the pressure pump (2) is connected to the input end of the nanofiltration membrane assembly (3) through a pipeline. The other output end of the electrofiltration membrane stack (1) is connected to the input end of the pressure pump (4) through a pipeline, and the output end of the pressure pump (4) is connected to the input end of the nanofiltration membrane assembly (5) through a pipeline. The output pipelines of nanofiltration membrane module one (3) and nanofiltration membrane module two (5) are combined and connected to the input end of the material separation and concentration device (6). One output end of the material separation and concentration device (6) is connected to the input end of the heating device (7).

7. An energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 6, wherein: The other output line of the nanofiltration membrane module 2 (5) merges with the other output line of the material separation and concentration device (6) and is then connected to one input end of the electro-membrane stack (1).

8. An energy efficient dechlorinated dilute brine de-nitrification device as claimed in claim 6, wherein: The DC-to-AC inverter (9) is connected to the first pressure pump (2), the second pressure pump (4), the material separation and concentration equipment (6), and the heating equipment (7) respectively via lines for power supply operation.

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