CN112225377A - System and method for resourceful treatment of high-salinity organic wastewater - Google Patents

System and method for resourceful treatment of high-salinity organic wastewater Download PDF

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CN112225377A
CN112225377A CN202011054756.6A CN202011054756A CN112225377A CN 112225377 A CN112225377 A CN 112225377A CN 202011054756 A CN202011054756 A CN 202011054756A CN 112225377 A CN112225377 A CN 112225377A
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sodium sulfate
salt
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hydrochloric acid
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CN112225377B (en
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曹宏斌
李玉平
高明
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Institute of Process Engineering of CAS
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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
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B7/00—Halogens; Halogen acids
    • C01B7/01—Chlorine; Hydrogen chloride
    • C01B7/07—Purification ; Separation
    • C01B7/0706—Purification ; Separation of hydrogen chloride
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
    • C01D5/16—Purification
    • 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
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
    • C02F1/10—Treatment of water, waste water, or sewage by heating by distillation or evaporation by direct contact with a particulate solid or with a fluid, as a heat transfer medium
    • C02F1/12—Spray evaporation
    • 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
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/722—Oxidation by peroxides
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/727—Treatment of water, waste water, or sewage by oxidation using pure oxygen or oxygen rich gas
    • 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
    • C02F1/72—Treatment of water, waste water, or sewage by oxidation
    • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/30—Organic compounds

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  • Inorganic Chemistry (AREA)
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  • Hydrology & Water Resources (AREA)
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Abstract

A system and a method for resourceful treatment of high-salinity organic wastewater are disclosed, wherein the system comprises five units, namely raw water concentration, atomization pyrolysis, sodium sulfate purification, hydrochloric acid recovery and tail gas treatment. The raw water concentration unit is used for concentrating the high-salinity organic wastewater; the atomization pyrolysis unit adds an acidifying agent into the concentrated solution for acidification, and simultaneously, after an oxidant is added, organic matters in water are thoroughly oxidized and removed through atomization pyrolysis, and hydrogen chloride gas and sodium sulfate mixed salt are obtained through separation; the sodium sulfate purification unit is used for dissolving, removing impurities and evaporating and crystallizing the separated sodium sulfate mixed salt, and the sodium sulfate is purified through recrystallization; the hydrochloric acid recovery unit is used for filtering and condensing the separated hydrogen chloride gas and recovering hydrochloric acid; and the tail gas treatment unit is used for deacidifying and purifying the residual tail gas of the hydrochloric acid recovery unit. The system and the method can realize the high-efficiency removal of organic matters in the high-salinity wastewater, and simultaneously recover hydrochloric acid and sodium sulfate crystallized salt; realizes the resource treatment of the high-salinity organic wastewater and has better application prospect.

Description

System and method for resourceful treatment of high-salinity organic wastewater
Technical Field
The invention belongs to the technical field of industrial wastewater treatment, relates to a system and a method for treating organic wastewater, and particularly relates to a system and a method for recycling high-salt organic wastewater.
Background
The heavily polluted enterprises such as steel, coal chemical industry, petrochemical industry, coal power, nonferrous metallurgy, fine chemical industry, pharmacy and the like not only have large water resource consumption, but also have large pollution discharge intensity. In order to deal with the dual pressure from water resources and the environment, a large number of enterprises adopt a membrane concentration technology to carry out zero emission reconstruction on a wastewater treatment system, a large amount of high-concentration brine which cannot be recycled is also generated while the water resources are recovered, and the part of wastewater has high salinity and also contains refractory organic matters. In order to reduce the amount of the high-concentration brine, some enterprises crystallize the salt in the wastewater by a simple evaporation method, and the main components of the generated waste salt are NaCl and Na2SO4The mixed salt has low value and contains refractory toxic organic matters, and can not be used as common industrial salt. Because the waste salt is not easy to solidify and is easy to dissolve in water, the long-term storage of the waste salt not only occupies a large amount of land, but also poses great threat to the environment.
In order to realize NaCl and Na in the high-salinity wastewater2SO4The resource recycling of the method is that at present, domestic high-salt organic wastewater is generally subjected to salt separation treatment firstly, and the adopted salt separation technology mainly comprises membrane salt separation and thermal salt separation. The membrane method salt separation mainly adopts a nanofiltration membrane to realize the separation of monovalent salt and divalent salt in high-salinity water. The thermal method for separating salt mainly utilizes fractional crystallization of different salt substances in the wastewater at different temperatures to realize separation. Before salt separation, however, an advanced oxidation method such as a Fenton oxidation method, an ozone catalytic oxidation method, an electrocatalytic oxidation method and the like is generally adopted to remove COD in the wastewater with high salt content. Because the organic matters in the wastewater cannot be completely removed by the advanced oxidation methods, the residual organic matters are continuously concentrated in the subsequent evaporation and crystallization process of the high-salt wastewater, most of the organic matters remain in the crystallization mother liquor and are finally mixed into the miscellaneous salt to be discharged, and the recycling of the crystallization salt is limited. There is still a need to further develop a method suitable for high-efficiency treatment of high-salinity wastewater to achieve near-zero discharge of high-salinity wastewater and resource utilization of salt-separated products.
Patents related to harmless and recycling treatment methods and systems for high-salt organic wastewater and waste salts are reported, for example, CN 109775785 a discloses a high-salt wastewater incineration desalting system and a treatment method thereof, and CN 102168857 a discloses a high-concentration salt-containing organic wastewater incineration device and process. CN 106731582 a discloses a method for comprehensively treating acidic waste gas containing hydrogen sulfide and solid waste miscellaneous salts, which utilizes the reaction of the recovered sulfuric acid and the solid waste miscellaneous salts containing sodium sulfate and sodium chloride to prepare sodium bisulfate, thereby realizing the recycling of miscellaneous salts. However, the miscellaneous salt also contains organic matters with high concentration and difficult degradation, and the resource utilization of the crystal salt product is still limited.
Therefore, a new system and a new method for treating high-salt organic wastewater are needed, which can thoroughly/deeply remove refractory organic matters in the high-salt wastewater, and can realize efficient separation of soluble inorganic salts in the high-salt wastewater, so that industrial salt products meeting application requirements are obtained, and recycling treatment of the high-salt organic wastewater is really realized.
Disclosure of Invention
Aiming at the problem that the prior art can not realize the high-efficiency treatment of the high-salt organic wastewater and the resource utilization of the waste salt, the invention provides a system and a method for the resource utilization treatment of the high-salt organic wastewater, and the method can realize the thorough removal of organic matters in the high-salt wastewater by utilizing an atomization pyrolysis technology; meanwhile, the method can recover high-purity sodium sulfate and hydrochloric acid, and realizes harmless and recycling treatment of high-salt organic wastewater.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a high-salinity organic wastewater recycling treatment system, which comprises a raw water concentration unit, an atomization pyrolysis unit and a sodium sulfate purification unit which are sequentially connected through pipelines; and a gas outlet of the atomization pyrolysis unit is sequentially connected with the hydrochloric acid recovery unit and the tail gas treatment unit through pipelines.
The raw water concentration unit is used for concentrating high-salinity organic wastewater; the atomization pyrolysis unit is connected with a concentrated solution outlet of the raw water concentration unit and is used for acidifying the concentrated solution, adding an oxidant, removing organic matters through atomization pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder; the sodium sulfate purification unit is connected with a salt powder discharge port of the atomization pyrolysis unit and is used for sequentially dissolving, removing impurities, evaporating, crystallizing and recrystallizing sodium sulfate mixed salt powder; the hydrochloric acid recovery unit is connected with a gas outlet of the atomization pyrolysis unit and is used for sequentially filtering and condensing hydrogen chloride gas and recovering hydrochloric acid; and the tail gas treatment unit is connected with a tail gas outlet of the hydrochloric acid recovery unit and is used for purifying the recovered tail gas.
Preferably, the raw water concentration unit comprises a raw water tank, a concentration device and a concentrated water tank which are connected in sequence.
Preferably, the concentration device comprises one or more of a pressure driven membrane concentration device, an electrically driven membrane concentration device or an evaporative concentration device.
Preferably, the atomization pyrolysis unit comprises a water pump, a fan, an acidifier supply device, an oxidant supply device, an atomization pyrolysis tower and a cyclone dust collector, wherein the water pump and the fan are respectively connected with the atomization pyrolysis tower through pipelines; the gas outlet of the atomization pyrolysis tower is connected with a cyclone dust collector, and the solid outlet of the cyclone dust collector and the salt powder outlet of the atomization pyrolysis tower are respectively connected with a sodium sulfate purification unit.
Preferably, the sodium sulfate purification unit comprises a dissolving tank, an impurity removal reaction tank, an evaporative crystallization device and a recrystallization device.
A feed inlet of the dissolving tank is communicated with a salt powder discharge port of the atomization pyrolysis tower and a solid outlet of the cyclone dust collector, and a water outlet of the dissolving tank is communicated with a water inlet of the impurity removal reaction tank through a pipeline; the water outlet of the impurity removal reaction tank is communicated with the water inlet of the evaporative crystallization device, and the crystal discharge port of the evaporative crystallization device is communicated with the recrystallization device through a pipeline; condensate liquid outlets of the evaporative crystallization device and the recrystallization device are communicated with the dissolving tank through pipelines; the mother liquor discharge ports of the evaporative crystallization device and the recrystallization device are communicated with a raw water tank of the raw water concentration unit through pipelines.
Preferably, the atomization pyrolysis tower comprises a tower body, an atomization device, a burner and a temperature control system. The combustor is used for providing hot air meeting the temperature requirement for the atomization pyrolysis tower under the control of the temperature control system, so that the hot air is contacted with the liquid sprayed into the tower body, the contact mode comprises any one of forward flow, reverse flow or cross flow, and a person skilled in the art can reasonably set the position of the atomization device according to the contact mode required by the process, so that organic matters in the liquid sprayed by the atomization device are decomposed under the action of the hot air provided by the combustor, and are separated to obtain mixed salt powder of hydrogen chloride gas and sodium sulfate; the temperature control system properly adjusts the working conditions of the burner according to the temperature measurement value in the atomization pyrolysis tower so as to ensure that the atomization pyrolysis tower stably operates under the set temperature condition.
The temperature control system is a conventional temperature control system in the field, and comprises but is not limited to a temperature measuring device and a temperature control device; the temperature measuring device comprises a thermocouple and/or a thermal resistor, and the temperature control device comprises a digital display and/or an industrial personal computer which are commonly used in the field; one skilled in the art can make a reasonable choice of temperature control system based on process requirements and the invention is not unduly limited herein.
Preferably, the atomizing means is a two-fluid nozzle.
Preferably, the hydrochloric acid recovery unit comprises a filter, a condenser and a hydrochloric acid storage tank which are connected in sequence.
Preferably, the filter medium in the filter in the hydrochloric acid recovery unit is a ceramic membrane. More preferably, the pore size of the ceramic membrane is 5 to 20 μm, and may be, for example, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm, but is not limited to the values recited, and other values not recited in the numerical range are also applicable; the ceramic membrane may have an open porosity of 30-50%, for example 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48% or 50%, but is not limited to the values recited, and other values not recited within the range of values are equally applicable.
Preferably, the material of the condenser comprises any one of graphite, ceramic, glass or polytetrafluoroethylene.
The high-salt organic wastewater recycling treatment system provided by the invention is characterized in that firstly, high-salt organic wastewater is concentrated, then an acidifying agent is added into concentrated solution for acidification, meanwhile, an oxidizing agent is added to improve the decomposition efficiency of organic matters difficult to degrade in the wastewater in the subsequent atomization pyrolysis treatment process, the organic matters are thoroughly removed, meanwhile, the hydrogen chloride and the sodium sulfate in atomized particles are efficiently separated, then, a subsequent sodium sulfate purification step and a hydrochloric acid recovery step are respectively carried out to obtain high-purity sodium sulfate crystalline salt and hydrochloric acid, and the hydrochloric acid recovery tail gas is purified by a tail gas treatment unit. The high-salinity organic wastewater recycling treatment system can efficiently remove organic matters in high-salinity wastewater, simultaneously recover hydrochloric acid and sodium sulfate crystal salt, really realize harmless, recycling, low-cost and short-flow treatment of the high-salinity organic wastewater, and ensure that the treatment process is environment-friendly and has no secondary pollution.
In a second aspect, the present invention provides a method for resource treatment of high-salinity organic wastewater by using the system of the first aspect, the method comprising the following steps:
(1) concentration: concentrating the high-salt organic wastewater to improve the content of soluble solids and organic matters in the high-salt organic wastewater to obtain a concentrated solution;
(2) atomizing and pyrolyzing: adding an acidifying agent into the concentrated solution obtained in the step (1) for acidification treatment, simultaneously adding an oxidant, removing organic matters in the concentrated solution through atomization and pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder;
(3) and (3) recovering hydrochloric acid: sequentially filtering and condensing the hydrogen chloride gas generated in the step (2), and recovering to obtain hydrochloric acid;
(4) sodium sulfate purification: dissolving the sodium sulfate mixed salt powder generated in the step (2), removing impurities, performing evaporative crystallization and recrystallization to obtain purified sodium sulfate crystalline salt, returning crystallization mother liquor to the step (1) for concentration again, and returning condensed water generated by evaporative crystallization and recrystallization to the step for dissolving the sodium sulfate mixed salt powder;
(5) tail gas treatment: and (4) conveying the hydrochloric acid recovery tail gas generated in the step (3) to a tail gas treatment unit for purification.
The main source of the high-salinity organic wastewater comprises any one or the combination of at least two of the steel industry, the coal chemical industry, the petrochemical industry, the coal and electricity industry, the nonferrous metallurgy industry, the fine chemical industry or the pharmaceutical industry and the like, typical but non-limiting combinations include the steel industry in combination with the coal chemical industry, the coal chemical industry in combination with the petrochemical industry, the petrochemical industry in combination with the coal electric industry, the coal electric industry in combination with the nonferrous metallurgy industry, the nonferrous metallurgy industry in combination with the fine chemical industry, the fine chemical industry in combination with the pharmaceutical industry, the steel industry, the coal chemical industry in combination with the coal electric industry, the coal chemical industry, the combination of the coal electric industry and the nonferrous metallurgy industry or the combination of the steel industry, the coal chemical industry, the petrochemical industry, the coal electric industry, the nonferrous metallurgy industry, the fine chemical industry and the pharmaceutical industry.
Preferably, the TDS in the high-salinity organic wastewater is more than or equal to 3 percent, such as 3 percent, 4 percent, 5 percent, 6 percent, 7 percent, 8 percent, 9 percent, 10 percent, 11 percent, 12 percent, 13 percent, 14 percent or 15 percent, but not limited to the recited values, and other values not recited in the numerical range are also applicable; COD.gtoreq.200 mg/L, for example 200mg/L, 500mg/L, 1000mg/L, 5000mg/L, 10000mg/L, 30000mg/L, 50000mg/L, 70000mg/L, 100000mg/L or 150000mg/L, but not limited to the recited values, and other values not recited in the numerical range are also applicable; the soluble inorganic salts comprise sodium chloride and sodium sulphate, wherein the ratio of the mass fraction of sodium chloride to sodium sulphate is ≥ 0.2:1, and may for example be 0.2:1, 0.5:1, 1.0:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1, but are not limited to the values listed, and other values not listed within the numerical range are equally applicable.
Preferably, the concentration treatment method of step (1) comprises one or a combination of at least two of pressure-driven membrane concentration, electric-driven membrane concentration and evaporation concentration, and typical but non-limiting combinations include a combination of pressure-driven membrane concentration and electric-driven membrane concentration, a combination of electric-driven membrane concentration and evaporation concentration, a combination of pressure-driven membrane concentration and evaporation concentration or a combination of pressure-driven membrane concentration, electric-driven membrane concentration and evaporation concentration. The method of concentration treatment can be appropriately selected by those skilled in the art according to the composition of the desired concentrated high-salt organic wastewater.
Preferably, the total organic and TDS content of the concentrate of step (1) is 30-60wt%, for example 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt% or 60wt%, but not limited to the recited values, and other values not recited within the range of values are equally applicable.
Preferably, the acidifying agent in step (2) comprises one or a combination of at least two of sulfuric acid, sodium bisulfate, or industrial waste acid. More preferably, the concentration of the sulfuric acid is 40 to 90 wt.%, for example, 40 wt.%, 50 wt.%, 60 wt.%, 70 wt.%, 80 wt.% or 90 wt.%, but not limited to the recited values, and other values not recited within the numerical range are equally applicable.
Preferably, the oxidizing agent in step (2) comprises any one or a combination of at least two of oxygen, ozone, persulfate, or peroxide, and typical but non-limiting combinations include oxygen and persulfate, oxygen and peroxide, ozone and persulfate, and ozone and peroxide. More preferably, the oxygen and ozone in the oxidant in step (2) are mixed with the concentrate by a two-fluid nozzle.
Preferably, the amount of the oxidant added in step (2) is 0.5-2.5% by mass of the treated amount of the concentrate, for example, 0.5%, 1%, 1.5%, 2% or 2.5%, but not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the mean diameter of the droplets formed after atomization of the concentrate in step (2) is from 10 to 100. mu.m, and may be, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, but is not limited to the values recited, and other values not recited in the numerical ranges are equally applicable.
Preferably, the temperature of the hot air introduced for the atomization pyrolysis in step (2) is 800 ℃ to 1100 ℃, such as 800 ℃, 850 ℃, 900 ℃, 950 ℃, 1000 ℃, 1050 ℃ or 1100 ℃, but not limited to the recited values, and other values not recited in the numerical ranges are equally applicable; the exhaust temperature is 500-700 ℃, for example 500 ℃, 550 ℃, 600 ℃, 640 ℃, 650 ℃, 660 ℃ or 700 ℃, but not limited to the enumerated values, and other unrecited values in the numerical range are also applicable; the atomized droplets have a residence time of from 2 to 5s, for example 2s, 2.5s, 3s, 3.5s, 4s, 4.5s or 5s, but are not limited to the values listed, and other values not listed in the numerical range are equally suitable.
Preferably, the gas after condensation in step (3) has a temperature of 20-40 ℃, for example 20 ℃, 21 ℃, 23 ℃, 25 ℃, 27 ℃, 29 ℃, 30 ℃, 31 ℃, 33 ℃, 35 ℃, 37 ℃, 39 ℃ or 40 ℃, but is not limited to the recited values, and other values not recited in the range of values are equally applicable.
Preferably, the hydrochloric acid concentration recovered by condensation in step (3) is from 5 to 15% by weight, for example 5%, 7%, 9%, 11%, 13% or 15% by weight, but is not limited to the values recited, and other values not recited in the range of values are equally applicable.
Preferably, the content of sodium sulfate in the sodium sulfate crystalline salt obtained in step (4) is 97.5wt% or more, for example 97.5wt%, 97.8wt%, 98wt%, 98.5wt% or 99wt%, but not limited to the recited values, and other values not recited in the numerical range are also applicable.
As a preferable technical solution of the method according to the second aspect of the present invention, the method comprises the steps of:
(1) concentration: concentrating the high-salt organic wastewater to improve the content of soluble solids and organic matters in the high-salt organic wastewater to obtain a concentrated solution;
(2) atomizing and pyrolyzing: adding an acidifying agent into the concentrated solution obtained in the step (1) for acidification treatment, and simultaneously adding an oxidant, wherein the adding amount of the oxidant accounts for 0.5-2.5% of the mass fraction of the treatment amount of the concentrated solution; removing organic matters in the concentrated solution through atomization pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder; the average diameter of the liquid drop particles formed after the atomization of the concentrated solution is 10-100 mu m, the temperature of hot air introduced by the atomization pyrolysis is 800-1100 ℃, the exhaust temperature is 500-700 ℃, and the retention time of the atomized liquid drops is 2-5 s;
(3) and (3) recovering hydrochloric acid: sequentially filtering and condensing the hydrogen chloride gas generated in the step (2), and recovering to obtain hydrochloric acid with the concentration of 5-15 wt%; the temperature of the condensed gas is 20-40 ℃;
(4) sodium sulfate purification: dissolving the sodium sulfate mixed salt powder generated in the step (2), and performing impurity removal, evaporative crystallization and recrystallization to obtain purified sodium sulfate crystalline salt, wherein the content of sodium sulfate in the sodium sulfate crystalline salt is more than or equal to 97.5 wt%; the crystallization mother liquor returns to the step (1) for secondary concentration treatment, and condensed water generated by evaporative crystallization and recrystallization returns to the step for dissolving the sodium sulfate mixed salt powder;
(5) tail gas treatment: conveying the hydrochloric acid recovery tail gas generated in the step (3) to a tail gas treatment unit for purification;
the source of the high-salt organic wastewater comprises any one or the combination of at least two of the industries of steel, coal chemical industry, petrifaction, coal power, nonferrous metallurgy, fine chemical industry, pharmacy and the like, wherein the TDS of the high-salt organic wastewater is more than or equal to 3 percent, the COD of the high-salt organic wastewater is more than or equal to 200mg/L, the soluble inorganic salt comprises sodium chloride and sodium sulfate, and the mass fraction ratio of the sodium chloride to the sodium sulfate is more than or equal to 0.2: 1;
the concentration treatment method of the step (1) comprises one or a combination of at least two of pressure-driven membrane concentration, electric-driven membrane concentration or evaporation concentration; the content of organic matters and TDS in the concentrated solution obtained in the step (1) is 30-60 wt%.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the invention, the high-salinity organic wastewater is concentrated, so that the water resource recovery is realized, the water treatment amount in the subsequent steps is reduced, the heat energy consumed in the atomization pyrolysis step is effectively reduced, and the concentration of the hydrochloric acid obtained by recovery is improved;
(2) according to the invention, the acidifying agent is added to ensure that the mixed salt in the concentrated solution is easy to separate into hydrogen chloride and sodium sulfate through subsequent atomization and pyrolysis;
(3) according to the invention, the oxidant is added into the concentrated solution, so that organic matters in the wastewater are easily oxidized and decomposed at high temperature and are efficiently removed;
(4) the invention utilizes the double-fluid nozzle to realize the full mixing of oxygen, ozone and concentrated solution in the oxidant and ensure the atomization effect of the wastewater, thus being beneficial to realizing the high-efficiency separation of hydrogen chloride and sodium sulfate and the thorough removal of organic matters in the wastewater;
(5) according to the invention, the removal of organic matters and the separation of inorganic salts in the wastewater are coupled to one operation step, so that the treatment time is short, the occupied area of equipment is saved, and the utilization rate of heat energy can be improved;
(6) the atomization pyrolysis temperature of the atomization pyrolysis tower provided by the invention can be adjusted according to the concentration and the property of organic matters in the wastewater, so that the organic matters are completely degraded, the fuel is saved, and the secondary pollution is avoided;
(7) according to the high-salt organic wastewater recycling treatment system, the high-temperature-resistant ceramic membrane filter is used for filtering fine salt powder particles in the tail gas of the atomization pyrolysis unit, so that secondary pollution caused by cooling of the flue gas is avoided;
(8) the sodium sulfate crystal salt and the hydrochloric acid recovered by the method can be sold as industrial raw materials, and the resource utilization of the high-salt organic wastewater is realized.
Drawings
FIG. 1 is a process flow diagram of a high-salinity organic wastewater recycling method provided by the invention;
FIG. 2 is a schematic view of a high-salinity organic wastewater recycling system provided by the invention;
FIG. 3 is a schematic structural view of a spray pyrolysis tower provided in example 1;
fig. 4 is a schematic structural view of a spray pyrolysis tower provided in example 2.
Wherein: 1, a raw water concentration unit; 2, atomizing a pyrolysis unit; 3, a sodium sulfate purification unit; 4, a hydrochloric acid recovery unit; 5, a tail gas treatment unit; 21, a tower body; 22, an atomizing device; 23, a burner; and 24, a temperature control system.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
As a preferred technical scheme of the present invention, fig. 1 is a process route diagram of a high-salinity organic wastewater recycling treatment method, and the specific process flow comprises the following steps:
(1) concentration: concentrating the high-salinity organic wastewater, wherein the total content of organic matters and TDS in the concentrated solution is 30-60 wt%;
(2) atomizing and pyrolyzing: adding an acidifying agent into the concentrated solution generated in the step (1) for acidification treatment, simultaneously adding an oxidizing agent, atomizing to enable the wastewater to form droplets with the diameter of 10-100 mu m, removing organic matters in the wastewater under a high-temperature environment provided by hot air, and enabling the separated hydrogen chloride and sodium sulfate to enter respective recovery steps;
(3) and (3) recovering hydrochloric acid: filtering the hydrogen chloride gas generated in the atomization pyrolysis step to remove fine particles, and then condensing and recovering to obtain hydrochloric acid with the concentration of 5-15 wt%;
(4) sodium sulfate purification: after dissolving the sodium sulfate mixed salt powder separated by atomization pyrolysis, removing impurities, evaporating for crystallization and recrystallizing to obtain purified sodium sulfate crystallized salt, wherein the content of sodium sulfate is more than or equal to 97.5wt%, the sodium sulfate crystallized salt can be sold as an industrial raw material, the recycling of salt is realized, crystallization mother liquor discharged in the crystallization process is returned to the step (1) for retreatment, and condensate of evaporation crystallization and recrystallization is returned to the step for dissolving the sodium sulfate mixed salt powder;
(5) tail gas treatment: and (4) purifying the hydrochloric acid recovery tail gas generated in the step (3) by a tail gas treatment unit.
The high-salt organic wastewater in the step (1) is high-salt organic wastewater which is from steel industry, coal chemical industry, petrochemical industry, coal power industry, nonferrous metallurgy industry, fine chemical industry or pharmaceutical industry, has TDS (total dissolved solids) of more than or equal to 3 percent and COD (chemical oxygen demand) of more than or equal to 200mg/L, mainly contains sodium chloride and sodium sulfate, and has the mass fraction ratio of the sodium chloride to the sodium sulfate of more than or equal to 0.2: 1.
Example 1
The embodiment provides a system for recycling high-salt organic wastewater, and a schematic diagram of the system for recycling high-salt organic wastewater is shown in fig. 2, and the system comprises a raw water concentration unit 1, an atomization pyrolysis unit 2 and a sodium sulfate purification unit 3 which are sequentially connected through a pipeline; the gas outlet of the atomization pyrolysis unit is sequentially connected with a hydrochloric acid recovery unit 4 and a tail gas treatment unit 5 through pipelines;
the raw water concentration unit 1 is used for concentrating high-salinity organic wastewater; the raw water concentration unit 1 comprises a raw water tank, a concentration device and a concentrated water tank which are connected in sequence through pipelines; the concentration device comprises any one of a pressure-driven membrane concentration device, an electric-driven membrane concentration device or an evaporation concentration device or a combination of at least two of the pressure-driven membrane concentration device, the electric-driven membrane concentration device and the evaporation concentration device. The raw water tank is used for collecting and storing high-salinity organic wastewater generated in the industrial production process. The enrichment facility is arranged in with waste water concentration, realizes water resource recovery, reduces 2 treatment capacities of atomizing pyrolysis unit, improves the hydrochloric acid concentration that retrieves among the hydrochloric acid recovery unit 4 and obtains. The concentrate tank is used for storing the concentrate and supplying it to the subsequent atomizing pyrolysis unit 2.
The atomization pyrolysis unit 2 is connected with an outlet of a concentrated water tank of the raw water concentration unit 1, and is used for acidifying concentrated solution, adding an oxidant, removing organic matters through atomization pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder; the atomization pyrolysis unit 2 comprises a water pump, a fan, an acidifier supply device, an oxidant supply device, an atomization pyrolysis tower and a cyclone dust collector. The schematic structural diagram of the atomization pyrolysis tower is shown in fig. 3, and includes a tower body 21, an atomization device 22, a burner 23, and a temperature control system 24. The atomization device 22 in the atomization pyrolysis tower adopts a two-fluid nozzle, the water pump conveys the concentrated solution added with the acidifying agent and the oxidant to the atomization device 22 through a water path, the fan conveys the gas medium to the atomization device 22 through a gas path to realize the sufficient atomization of the liquid, the separation of hydrogen chloride and sodium sulfate in the atomized particles is realized under the high-temperature hot air environment provided by the burner 23 at the bottom of the atomization pyrolysis tower, and meanwhile, the organic components in the particles are thoroughly removed under the action of high temperature and the oxidant; wherein the concentrated solution sprayed from the atomizer 22 is brought into counter-current contact with hot air supplied from the burner 23. And the cyclone dust collector separates the sodium sulfate mixed salt powder from the tail gas discharged from the atomization pyrolysis tower. The temperature control system appropriately adjusts the working conditions of the burner 23 according to the temperature measurement value in the atomization pyrolysis tower so as to ensure that the atomization pyrolysis tower stably operates under the set temperature condition.
The sodium sulfate purification unit 3 is connected with the salt powder discharge port of the atomization pyrolysis unit 2 and is used for sequentially dissolving, removing impurities, evaporating, crystallizing and recrystallizing sodium sulfate mixed salt powder; the sodium sulfate purification unit 3 comprises a dissolving tank, an impurity removal reaction tank, an evaporation crystallization device and a recrystallization device. The dissolving tank receives the sodium sulfate mixed salt powder separated by the atomization pyrolysis unit 2 and condensate recovered by the evaporation crystallization device and the recrystallization device of the unit to form a sodium sulfate solution; the impurity removal reaction tank is used for removing impurities in the sodium sulfate solution and improving the quality of sodium sulfate crystal salt; the evaporation crystallization device concentrates and crystallizes the sodium sulfate solution after impurity removal to realize primary purification of sodium sulfate, condensed water generated in the evaporation crystallization and recrystallization processes flows back to the dissolution pool of the unit, crystallization mother liquor flows back to the raw water tank of the raw water concentration unit 1 to be treated again, and sodium sulfate crystals generated by evaporation crystallization enter the recrystallization device to realize further purification.
The hydrochloric acid recovery unit is connected with a gas outlet of the atomization pyrolysis unit 2 and is used for sequentially filtering and condensing hydrogen chloride gas and recovering hydrochloric acid; the hydrochloric acid recovery unit 4 comprises a filter, a condenser and a hydrochloric acid storage tank which are connected in sequence. The filter is connected with a gas outlet of the cyclone dust collector of the atomization pyrolysis unit 2 through a pipeline, and further purifies the hydrogen chloride gas. The filter adopts a ceramic membrane filter element, the aperture of the ceramic membrane is 5-20 mu m, the aperture ratio is 30-50%, the filter can realize filtration treatment at high temperature, and secondary pollution caused by flue gas cooling is avoided. The condenser is connected with the outlet of the filter and used for cooling the tail gas, the cooled hydrochloric acid flows into the hydrochloric acid storage tank, the non-condensable gas discharged by the condenser enters the tail gas treatment unit 5, and the condenser can be made of any one of graphite, ceramic, glass or polytetrafluoroethylene.
And the tail gas treatment unit 5 is connected with the tail gas outlet of the hydrochloric acid recovery unit 4 and is used for purifying the recovered tail gas.
Example 2
Compared with the system in the embodiment 1, the system in the high-salt organic wastewater recycling treatment system is the same as the system in the embodiment 1 except that the schematic structural diagram of the atomization pyrolysis tower in the system in the high-salt organic wastewater recycling treatment system is shown in fig. 4, and the concentrated solution sprayed by the atomization device 22 is in concurrent contact with the hot air provided by the burner 23.
Comparative example 1
This comparative example provides a system for resourceful treatment of high-salt organic wastewater, compared with example 1, except that the atomization pyrolysis unit is replaced by a heating and stirring reaction device which is conventional in the field, the rest is the same as example 1.
The heating and stirring reaction device is connected with an outlet of a concentrated water tank of the raw water concentration unit 1 and is used for acidifying concentrated solution, adding an oxidant and then separating hydrogen chloride gas and sodium sulfate mixed salt powder by heating and stirring; the heating and stirring reaction device comprises a heating reaction kettle, a stirrer, an acidifier supply device, an oxidant supply device and a temperature control system.
The acidifying agent supply device is used for adding an acidifying agent into the concentrated solution for acidifying treatment; the oxidant supply device is used for adding an oxidant into the concentrated solution after the acidification treatment; the stirrer is used for stirring and heating liquid in the reaction kettle; the temperature control system is used for controlling the temperature in the heating reaction kettle.
Due to the limitation of the material of the heating reaction kettle and the characteristic that sodium salt is easy to coke at high temperature, the heating and stirring reaction device is difficult to stably operate at high temperature for a long time. Macromolecular degradation-resistant organic matters in the concentrated solution are difficult to completely decompose, so that the organic matters are remained in the sodium sulfate solution, and the purity of the subsequent obtained sodium sulfate is influenced.
Application example 1
The present application example provides a method for performing resource treatment on high-salt organic wastewater by using the high-salt organic wastewater resource treatment system provided in example 1, and the water quality of the high-salt organic wastewater to be treated is as follows: TDS 6%, COD 30000mg/L, Na+ 21600mg/L、Cl-20000mg/L and SO4 2-18000 mg/L; the method comprises the following steps:
(1) concentrating the high-salt organic wastewater by adopting a method of combining electric drive membrane concentration with MVR evaporation concentration to obtain a concentrated solution with TDS of 30wt% and COD content of 150000 mg/L;
(2) adding sulfuric acid with the concentration of 40wt% into the concentrated solution obtained in the step (1) as an acidifier, adding sodium persulfate with the mass of 1.5% of that of the concentrated solution as an oxidant, atomizing to form liquid drops with the average diameter of 50 micrometers, setting the temperature of hot air introduced in the atomizing pyrolysis process to be 1000 ℃, the residence time of the liquid drops to be 2.6s, and the exhaust temperature to be 650 ℃, so as to obtain hydrogen chloride tail gas and sodium sulfate mixed salt powder;
(3) hydrogen chloride tail gas separated by atomization pyrolysis enters a hydrochloric acid recovery step, the tail gas is filtered and condensed, the temperature of the condensed gas is set to be 40 ℃, and 10wt% hydrochloric acid is recovered;
(4) sodium sulfate mixed salt powder separated by atomization pyrolysis enters a sodium sulfate purification step, and the content of sodium sulfate in the crystal salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is more than or equal to 99wt%, so that the crystal salt can be sold as industrial salt.
Application example 2
The present application example provides a method for performing resource treatment on high-salt organic wastewater by using the high-salt organic wastewater resource treatment system provided in example 1, and the water quality of the high-salt organic wastewater to be treated is as follows: TDS 13%, COD 100000mg/L, Na+ 47800mg/L、Cl-56000mg/L and SO4 2-24000 mg/L; the method comprises the following steps:
(1) the high-salt organic wastewater is concentrated by adopting an MVR evaporation concentration method to obtain a concentrated solution with TDS of 30wt% and COD content of 230000 mg/L.
(2) Adding sulfuric acid with the concentration of 70wt% into the concentrated solution obtained in the step (1) as an acidifying agent, adding hydrogen peroxide with the mass of 2.5% of that of the concentrated solution as an oxidant, atomizing to form liquid drops with the average diameter of 10 micrometers, setting the temperature of hot air introduced in the atomizing pyrolysis process to be 1100 ℃, the residence time of the liquid drops to be 3s, and the air exhaust temperature to be 700 ℃, so as to obtain mixed salt powder of hydrogen chloride tail gas and sodium sulfate;
(3) hydrogen chloride tail gas separated by atomization pyrolysis enters a hydrochloric acid recovery step, the tail gas is filtered and condensed, the temperature of the condensed gas is set to be 30 ℃, and 13wt% hydrochloric acid is recovered;
(4) sodium sulfate mixed salt powder separated by atomization pyrolysis enters a sodium sulfate purification step, and the sodium sulfate content in the crystal salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is more than or equal to 98.5wt%, so that the crystal salt can be sold as industrial salt.
Application example 3
The present application example provides a method for performing resource treatment on high-salt organic wastewater by using the high-salt organic wastewater resource treatment system provided in example 2, and the water quality of the high-salt organic wastewater to be treated is as follows: TDS 3%, COD 10000mg/L, Na+ 11000mg/L、Cl-14000mg/L and SO4 2-4000 mg/L; the method comprises the following steps:
(1) concentrating the high-salt organic wastewater by adopting a pressure-driven membrane concentration and electric-driven membrane concentration combined MVR evaporation concentration method to obtain a concentrated solution with TDS of 30wt% and COD content of 100000 mg/L;
(2) adding 90wt% sulfuric acid serving as an acidifying agent into the concentrated solution obtained in the step (1), adding 0.5 wt% of sodium persulfate serving as an oxidant in the mass of the concentrated solution, mixing and atomizing ozone serving as an oxidant and the concentrated solution through a two-fluid nozzle to form liquid drops with the average diameter of 100 microns through atomization, and setting the temperature of hot air introduced in the atomization pyrolysis process to be 800 ℃, the residence time of the liquid drops to be 2.3s and the exhaust temperature to be 500 ℃ to obtain mixed salt powder of hydrogen chloride tail gas and sodium sulfate;
(3) hydrogen chloride tail gas separated by atomization pyrolysis enters a hydrochloric acid recovery step, the tail gas is filtered and condensed, the temperature of the condensed gas is set to be 25 ℃, and 14wt% hydrochloric acid is recovered;
(4) sodium sulfate mixed salt powder separated by atomization pyrolysis enters a sodium sulfate purification step, and the content of sodium sulfate in the crystal salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is more than or equal to 97.5wt%, so that the crystal salt can be sold as industrial salt.
Application example 4
The present application example provides a method for performing resource treatment on high-salt organic wastewater by using the high-salt organic wastewater resource treatment system provided in example 1, and the water quality of the high-salt organic wastewater to be treated is as follows: TDS 5%, COD 30000mg/L, Na+ 19000mg/L、Cl-20000mg/L and SO4 2-10000 mg/L; the method comprises the following steps:
(1) concentrating the high-salt organic wastewater by adopting a method of combining electric drive membrane concentration with MVR evaporation concentration to obtain a concentrated solution with TDS of 28wt% and COD content of 168000 mg/L;
(2) adding sodium bisulfate solid into the concentrated solution obtained in the step (1) as an acidifying agent, adding hydrogen peroxide accounting for 1% of the mass of the concentrated solution as an oxidant, atomizing to form liquid drops with the average diameter of 80 microns, setting the temperature of hot air introduced in the atomization pyrolysis process to be 900 ℃, the residence time of the liquid drops to be 2.1s and the exhaust temperature to be 630 ℃, and obtaining mixed salt powder of hydrogen chloride tail gas and sodium sulfate;
(3) hydrogen chloride tail gas separated by atomization pyrolysis enters a hydrochloric acid recovery step, the tail gas is filtered and condensed, the temperature of the condensed gas is set to be 35 ℃, and 11wt% hydrochloric acid is recovered;
(4) sodium sulfate mixed salt powder separated by atomization pyrolysis enters a sodium sulfate purification step, and the sodium sulfate content in the crystal salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is more than or equal to 98wt%, so that the crystal salt can be sold as industrial salt.
Application example 5
The application example provides a method for recycling high-salt organic wastewater by using the recycling treatment system for high-salt organic wastewater provided in the embodiment 1,the water quality of the high-salinity organic wastewater to be treated is as follows: TDS 10%, COD 30000mg/L, Na+ 38000mg/L、Cl-50000mg/L and SO4 2-12000 mg/L; the method comprises the following steps:
(1) concentrating the high-salt organic wastewater by adopting a method of combining electric drive membrane concentration with MVR evaporation concentration to obtain a concentrated solution with TDS of 30wt% and COD content of 90000 mg/L;
(2) adding industrial waste acid serving as an acidifying agent into the concentrated solution obtained in the step (1), adding 2% of sodium persulfate serving as an oxidant in mass of the concentrated solution, simultaneously mixing and atomizing oxygen serving as the oxidant and the concentrated solution through a two-fluid nozzle to form liquid drops with the average diameter of 10 microns through atomization, and setting the temperature of hot air introduced in the atomization pyrolysis process to 850 ℃, the residence time of the liquid drops to be 2s and the exhaust temperature to be 590 ℃, so as to obtain mixed salt powder of hydrogen chloride tail gas and sodium sulfate;
(3) hydrogen chloride tail gas separated by atomization pyrolysis enters a hydrochloric acid recovery step, the tail gas is filtered and condensed, the temperature of the condensed gas is set to be 20 ℃, and 15wt% hydrochloric acid is recovered;
(4) sodium sulfate mixed salt powder separated by atomization pyrolysis enters a sodium sulfate purification step, and the content of sodium sulfate in the crystal salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is more than or equal to 99wt%, so that the crystal salt can be sold as industrial salt.
Application example 6
The present application example provides a method for performing resource treatment on high-salt organic wastewater by using the high-salt organic wastewater resource treatment system provided in example 1, and the water quality of the high-salt organic wastewater to be treated is as follows: TDS 5%, COD 200mg/L, Na+18000mg/L、Cl-6000mg/L and SO4 2-30000 mg/L; the method comprises the following steps:
(1) concentrating the high-salt organic wastewater by adopting a method of combining electric drive membrane concentration with MVR evaporation concentration to obtain a concentrated solution with TDS of 30wt% and COD content of 1200 mg/L;
(2) adding industrial waste acid serving as an acidifying agent into the concentrated solution obtained in the step (1), simultaneously mixing and atomizing oxygen serving as an oxidant and the concentrated solution through a two-fluid nozzle, atomizing to form liquid drops with the average diameter of 100 microns, setting the temperature of hot air introduced in the atomization pyrolysis process to be 1100 ℃, the residence time of the liquid drops to be 5s, and the exhaust temperature to be 500 ℃, and obtaining mixed salt powder of hydrogen chloride tail gas and sodium sulfate;
(3) hydrogen chloride tail gas separated by atomization pyrolysis enters a hydrochloric acid recovery step, the tail gas is filtered and condensed, the temperature of the condensed gas is set to be 20 ℃, and 5wt% hydrochloric acid is recovered;
(4) sodium sulfate mixed salt powder separated by atomization pyrolysis enters a sodium sulfate purification step, and the content of sodium sulfate in the crystal salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is more than or equal to 99wt%, so that the crystal salt can be sold as industrial salt.
Comparative application example 1
The comparative application example provides a method for performing resource treatment on high-salt organic wastewater by using the high-salt organic wastewater resource treatment system provided in the comparative example 1, except that the atomization pyrolysis process is replaced by a conventional heating and stirring reaction process, and other process parameters are consistent with those of the application example 1.
The water quality of the high-salinity organic wastewater to be treated is as follows: TDS 6%, COD 30000mg/L, Na+ 21600mg/L、Cl-20000mg/L and SO4 2-18000 mg/L; the method comprises the following steps:
(1) concentrating the high-salt organic wastewater by adopting a method of combining electric drive membrane concentration with MVR evaporation concentration to obtain a concentrated solution with TDS of 30wt% and COD content of 150000 mg/L;
(2) adding sulfuric acid with the concentration of 40wt% into the concentrated solution obtained in the step (1) as an acidifier, adding sodium persulfate with the mass of 1.5% of that of the concentrated solution as an oxidant, and heating and stirring at 200 ℃ to separate hydrogen chloride tail gas and sodium sulfate salt particles;
(3) hydrogen chloride tail gas separated by heating and stirring enters a hydrochloric acid recovery step, the tail gas is condensed after being filtered, the temperature of the condensed gas is set to be 40 ℃, and hydrochloric acid is recovered;
(4) sodium sulfate particles enter a sodium sulfate purification step, and the content of sodium sulfate in the crystalline salt obtained by impurity removal, evaporative crystallization and recrystallization recovery is less than or equal to 80wt%, so that the sodium sulfate particles cannot be sold as industrial salt.
In summary, the high-salt organic wastewater recycling treatment system provided by the invention firstly concentrates the high-salt organic wastewater, then adds the acidifying agent into the concentrated solution for acidification, and simultaneously adds the oxidant to improve the decomposition efficiency of the organic matters difficult to degrade in the wastewater in the subsequent atomization pyrolysis treatment process, so as to realize complete removal of the organic matters, simultaneously, the hydrogen chloride and the sodium sulfate in the atomized particles are also efficiently separated, then, the subsequent sodium sulfate purification step and the hydrochloric acid recovery step are respectively carried out to obtain high-purity sodium sulfate crystalline salt and hydrochloric acid, and the hydrochloric acid recovery tail gas is purified by the tail gas treatment unit. The high-salinity organic wastewater recycling treatment system can efficiently remove organic matters in high-salinity wastewater, simultaneously recover hydrochloric acid and sodium sulfate crystal salt, really realize harmless, recycling, low-cost and short-flow treatment of the high-salinity organic wastewater, and ensure that the treatment process is environment-friendly and has no secondary pollution.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (10)

1. A system for recycling high-salt organic wastewater is characterized by comprising a raw water concentration unit, an atomization pyrolysis unit and a sodium sulfate purification unit which are sequentially connected through pipelines; a gas outlet of the atomization pyrolysis unit is sequentially connected with a hydrochloric acid recovery unit and a tail gas treatment unit through pipelines;
the raw water concentration unit is used for concentrating the high-salinity organic wastewater;
the atomization pyrolysis unit is connected with a concentrated solution outlet of the raw water concentration unit and is used for acidifying the concentrated wastewater, adding an oxidant, removing organic matters through atomization pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder;
the sodium sulfate purification unit is connected with a salt powder discharge port of the atomization pyrolysis unit and is used for sequentially dissolving, removing impurities, evaporating, crystallizing and recrystallizing sodium sulfate mixed salt powder;
the hydrochloric acid recovery unit is connected with a gas outlet of the atomization pyrolysis unit and is used for sequentially filtering and condensing hydrogen chloride gas and recovering hydrochloric acid;
and the tail gas treatment unit is connected with a tail gas outlet of the hydrochloric acid recovery unit and is used for purifying the recovered tail gas.
2. The system as claimed in claim 1, wherein the raw water concentrating unit comprises a raw water tank, a concentrating device and a concentrated water tank which are connected in sequence;
preferably, the concentration device comprises one or more of a pressure driven membrane concentration device, an electrically driven membrane concentration device or an evaporative concentration device;
preferably, the atomization pyrolysis unit comprises a water pump, a fan, an acidifier supply device, an oxidant supply device, an atomization pyrolysis tower and a cyclone dust collector, wherein the water pump and the fan are respectively connected with the atomization pyrolysis tower through pipelines; the gas outlet of the atomization pyrolysis tower is connected with a cyclone dust collector, and the solid outlet of the cyclone dust collector and the salt powder outlet of the atomization pyrolysis tower are respectively connected with a sodium sulfate purification unit.
3. The system of claim 2, wherein the sodium sulfate purification unit comprises a dissolving tank, an impurity removal reaction tank, an evaporative crystallization device and a recrystallization device;
a feed inlet of the dissolving tank is communicated with a salt powder discharge port of the atomization pyrolysis tower and a solid outlet of the cyclone dust collector, and a water outlet of the dissolving tank is communicated with a water inlet of the impurity removal reaction tank through a pipeline; the water outlet of the impurity removal reaction tank is communicated with the water inlet of the evaporative crystallization device, and the crystal discharge port of the evaporative crystallization device is communicated with the recrystallization device through a pipeline; condensate liquid outlets of the evaporative crystallization device and the recrystallization device are communicated with the dissolving tank through pipelines; the mother liquor discharge ports of the evaporative crystallization device and the recrystallization device are communicated with a raw water tank of the raw water concentration unit through pipelines.
4. The system of claim 2, wherein the atomizing pyrolysis tower comprises a tower body, an atomizing device, a burner and a temperature control system;
preferably, the atomizing means is a two-fluid nozzle.
5. The system of claim 1, wherein the hydrochloric acid recovery unit comprises a filter, a condenser and a hydrochloric acid storage tank which are connected in sequence;
preferably, the filter media in the filter is a ceramic membrane; more preferably, the ceramic membrane has a pore size of 5-20 μm and an open porosity of 30-50%;
preferably, the material of the condenser comprises any one of graphite, ceramic, glass or polytetrafluoroethylene.
6. A method for resource treatment of high-salinity organic wastewater by applying the system of any one of claims 1-5, characterized in that the method comprises the following steps:
(1) concentration: concentrating the high-salt organic wastewater to improve the content of soluble solids and organic matters in the high-salt organic wastewater to obtain a concentrated solution;
(2) atomizing and pyrolyzing: adding an acidifying agent into the concentrated solution obtained in the step (1) for acidification treatment, simultaneously adding an oxidant, removing organic matters in the concentrated solution through atomization and pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder;
(3) and (3) recovering hydrochloric acid: sequentially filtering and condensing the hydrogen chloride gas generated in the step (2), and recovering to obtain hydrochloric acid;
(4) sodium sulfate purification: dissolving the sodium sulfate mixed salt powder generated in the step (2), removing impurities, performing evaporative crystallization and recrystallization to obtain purified sodium sulfate crystalline salt, returning crystallization mother liquor to the step (1) for concentration again, and returning condensed water generated by evaporative crystallization and recrystallization to the step for dissolving the sodium sulfate mixed salt powder;
(5) tail gas treatment: and (4) conveying the hydrochloric acid recovery tail gas generated in the step (3) to a tail gas treatment unit for purification.
7. The method of claim 6, wherein the source of the high-salinity organic wastewater comprises one or more of steel, coal chemical, petrochemical, coal electric, nonferrous metallurgy, fine chemical, and pharmaceutical industries;
preferably, the TDS of the high-salt organic wastewater is more than or equal to 3 percent, the COD of the high-salt organic wastewater is more than or equal to 200mg/L, and the soluble inorganic salt comprises sodium chloride and sodium sulfate, wherein the mass fraction ratio of the sodium chloride to the sodium sulfate is more than or equal to 0.2: 1;
preferably, the concentration treatment method of step (1) comprises one or more of pressure-driven membrane concentration, electrically-driven membrane concentration or evaporation concentration;
preferably, the total content of organic matters and TDS in the concentrated solution in the step (1) is 30-60 wt%.
8. The process of claim 6, wherein the acidifying agent in step (2) comprises one or more of sulfuric acid, sodium bisulfate, and spent industrial acid; more preferably, the concentration of the sulfuric acid is 40-90 wt%;
preferably, the oxidant in step (2) comprises one or more of oxygen, ozone, a persulfate or a peroxide; more preferably, the oxygen and ozone in the oxidant in step (2) are mixed with the concentrate through a two-fluid nozzle;
preferably, the adding amount of the oxidant in the step (2) accounts for 0.5-2.5% of the treatment amount of the concentrated solution;
preferably, the average diameter of the droplet particles formed after the concentrated solution is atomized in the step (2) is 10-100 μm;
preferably, the temperature of the hot air introduced in the atomization pyrolysis in the step (2) is 800-.
9. The method according to claim 6, wherein the gas after condensation in step (3) has a temperature of 20-40 ℃;
preferably, the concentration of hydrochloric acid recovered by condensation in step (3) is 5-15 wt%;
preferably, the content of the sodium sulfate in the sodium sulfate crystalline salt obtained in the step (4) is more than or equal to 97.5 wt%.
10. A method according to any of claims 6-9, characterized in that the method comprises the steps of:
(1) concentration: concentrating the high-salt organic wastewater to improve the content of soluble solids and organic matters in the high-salt organic wastewater to obtain a concentrated solution;
(2) atomizing and pyrolyzing: adding an acidifying agent into the concentrated solution obtained in the step (1) for acidification treatment, and simultaneously adding an oxidant, wherein the adding amount of the oxidant accounts for 0.5-2.5% of the mass fraction of the treatment amount of the concentrated solution; removing organic matters in the concentrated solution through atomization and pyrolysis, and separating to obtain hydrogen chloride gas and sodium sulfate mixed salt powder; the average diameter of the liquid drop particles formed after the atomization of the concentrated solution is 10-100 mu m, the temperature of hot air introduced by the atomization pyrolysis is 800-1100 ℃, the exhaust temperature is 500-700 ℃, and the retention time of the atomized liquid drops is 2-5 s;
(3) and (3) recovering hydrochloric acid: sequentially filtering and condensing the hydrogen chloride gas generated in the step (2), and recovering to obtain hydrochloric acid with the concentration of 5-15 wt%; the temperature of the condensed gas is 20-40 ℃;
(4) sodium sulfate purification: dissolving the sodium sulfate mixed salt powder generated in the step (2), and performing impurity removal, evaporative crystallization and recrystallization to obtain purified sodium sulfate crystalline salt, wherein the content of sodium sulfate in the sodium sulfate crystalline salt is more than or equal to 97.5 wt%; the crystallization mother liquor returns to the step (1) for secondary concentration treatment, and condensed water generated by evaporative crystallization and recrystallization returns to the step for dissolving the sodium sulfate mixed salt powder;
(5) tail gas treatment: conveying the hydrochloric acid recovery tail gas generated in the step (3) to a tail gas treatment unit for purification;
the source of the high-salt organic wastewater comprises one or more of steel, coal chemical industry, petrifaction, coal power, nonferrous metallurgy, fine chemical industry and pharmaceutical industry, the TDS of the high-salt organic wastewater is more than or equal to 3%, the COD of the high-salt organic wastewater is more than or equal to 200mg/L, the soluble inorganic salt comprises sodium chloride and sodium sulfate, and the mass fraction ratio of the sodium chloride to the sodium sulfate is more than or equal to 0.2: 1;
the concentration treatment method of the step (1) comprises one or more of pressure-driven membrane concentration, electric-driven membrane concentration or evaporation concentration; the content of organic matters and TDS in the concentrated solution obtained in the step (1) is 30-60 wt%.
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