Mother liquor evaporation treatment system and mother liquor evaporation treatment method

Abstract

The invention discloses a mother liquor evaporation treatment system and a mother liquor evaporation treatment method. The mother liquor evaporation treatment system comprises an adjusting tank, a first reaction tank, a first filter pressing mechanism, a second reaction tank, a second filter pressing mechanism, an evaporation water inlet tank and an evaporation system which are connected in sequence, a filter aid and an acid solution or an alkali solution can be added into the first reaction tank, and the first reaction tank is used for removing organic matters from the evaporation crystallization mother liquor and decoloring the evaporation crystallization mother liquor; the first filter pressing mechanism is used for carrying out filter pressing treatment on reaction liquid from the first reaction tank, an acid solution or an alkali solution, a filter aid and a modifier can be added into the second reaction tank, and the second reaction tank is used for carrying out organic matter removal and decoloration treatment on filtrate from the first filter pressing mechanism; the second filter pressing mechanism is used for carrying out filter pressing treatment on the reaction liquid from the second reaction tank, and the evaporation system is used for carrying out evaporation treatment on the filter pressing liquid to obtain crystal salt. The finally obtained filtrate is clear and transparent, and the crystalline salt with good granularity and whiteness is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of water treatment, and in particular to a mother liquor evaporation treatment system and a mother liquor evaporation treatment system method. Background Art

[0002] With the continuous development of industry, water shortage and insufficient water environment capacity have become important bottlenecks restricting the development of modern industry. At present, the treatment of industrial wastewater mainly adopts the technical route of "pretreatment-membrane concentration-salt separation and crystallization" to basically achieve zero discharge and reuse of industrial wastewater. In the actual treatment process, there are a large number of organic pollutants in the evaporation mother liquor, which leads to problems such as wall sticking, boiling, scaling, etc. in the evaporation equipment, thereby causing the evaporation energy efficiency to decrease and clogging the tubes of the heat exchanger; and after the organic matter is enriched, in the process of salt lattice formation, the enriched viscous substances will be adsorbed on the lattice, destroying the regularity of the lattice, reducing the lattice strength, and causing lattice distortion, resulting in small salt particles, large specific surface area, large adsorption capacity, poor salt quality, high water content, and ineffective evaporation treatment. Summary of the invention

[0003] Based on this, it is necessary to provide a mother liquor evaporation treatment system. The mother liquor treated by the mother liquor evaporation treatment system of the present invention can finally obtain a clear and transparent filtrate, and various organic substances that affect evaporation can be effectively removed, and re-evaporation can obtain crystalline salt with good particle size and whiteness.

[0004] An embodiment of the present application provides a mother liquid evaporation treatment system.

[0005] A mother liquor evaporation treatment system comprises a first reaction tank, a first filter press mechanism, a second reaction tank, a second filter press mechanism, an evaporation water inlet tank and an evaporation system connected in sequence, wherein a filter aid and an acid solution or an alkaline solution are added into the first reaction tank, the first reaction tank is used to remove organic matter and decolorize the evaporation crystallization mother liquor, the first filter press mechanism is used to perform filter press treatment on the reaction liquid from the first reaction tank, the second reaction tank can be added with an acid solution or an alkaline solution, a filter aid and a modifier, the second reaction tank is used to remove organic matter and decolorize the filtrate from the first filter press mechanism, the second filter press mechanism is used to perform filter press treatment on the reaction liquid from the second reaction tank, the evaporation water inlet tank is used to homogenize and uniformly measure the filtrate from the second filter press mechanism, and the evaporation system is used to evaporate the filtrate from the evaporation water inlet tank after homogenization and uniformity to obtain crystalline salt.

[0006] In some of the embodiments, the inner lining of the first reaction tank has a high temperature resistant anti-corrosion layer, and the high temperature resistant anti-corrosion layer has a tolerance temperature of not less than 80°C.

[0007] In some embodiments, a stirring mechanism is disposed inside the first reaction tank.

[0008] In some embodiments, the mother liquor evaporation treatment system further comprises a regulating tank, and the regulating tank is connected to the first reaction tank so as to homogenize and uniformly measure the evaporated mother liquor before the mother liquor enters the first reaction tank.

[0009] In some embodiments, the pH value in the first reaction tank is controlled to be 1-3 by the acid solution.

[0010] In some embodiments, the pH value in the first reaction tank is controlled to be 12-14 by the alkaline solution.

[0011] In some embodiments, the first filter press mechanism adopts a plate and frame diaphragm filter press, the moisture content of the filter cake after filtration by the first filter press mechanism is ≤65%, and the filter cloth of the first filter press mechanism is made of polyester material with a mesh size between 300 and 400.

[0012] In some embodiments, the second filter press mechanism adopts a plate and frame diaphragm filter press, the moisture content of the filter cake after filtration by the second filter press mechanism is ≤65%, and the filter cloth of the second filter press mechanism is made of polyester material with a mesh size between 300 and 400.

[0013] In some embodiments, the evaporation system includes a single steam kettle, a plate heat exchanger, a vacuum unit, a centrifuge, a centrifuge post-liquid tank and a cold analysis tank, wherein the evaporation water inlet tank, the single steam kettle, the centrifuge, the centrifuge post-liquid tank and the cold analysis tank are connected in sequence, the vacuum unit and the plate heat exchanger are connected to the single steam kettle in sequence, the negative pressure of the single steam kettle is controlled to be -50Kpa~-20Kpa, the single steam kettle is used to evaporate the filtrate after homogenization and uniformity from the evaporation water inlet tank, the centrifuge is used to centrifuge the evaporated mother liquor after evaporation to obtain crystalline salt, the post-liquid after centrifugation of the centrifuge enters the centrifuge post-liquid tank, the centrifuge post-liquid tank regularly discharges the post-liquid to the cold analysis tank, and the cold analysis tank intermittently feeds the centrifuge after the solid material is precipitated from the post-liquid.

[0014] In some of the embodiments, the centrifuge post-spin liquid tank is also connected to the regulating tank to enable part of the concentrated post-spin liquid to flow back to the regulating tank for further pretreatment.

[0015] In some embodiments, the centrifuge post-flushing liquid tank is also connected to the single distillation kettle, so that the post-flushing liquid in the centrifuge post-flushing liquid tank can flow back to the single distillation kettle for circulating steaming.

[0016] In some embodiments, the modifier includes a liquid resin, the liquid resin includes a dicyandiamide formaldehyde condensation resin, the dilution concentration of the modifier is 10%, the dosage of the modifier is 1000 mg / L~5000 mg / L, the decolorization rate of the modifier is not less than 80%, and the COD removal rate of the liquid resin is not less than 60%.

[0017] In some embodiments, the filter aid includes one or more of activated carbon, diatomaceous earth, and perlite, and the dosage of the filter aid is 500 mg / L~2000 mg / L.

[0018] An embodiment of the present application provides a mother liquid evaporation treatment method.

[0019] A mother liquid evaporation treatment method using the above-mentioned mother liquid evaporation treatment system comprises the following steps:

[0020] After being homogenized and uniformly weighed, the evaporation crystallization mother liquor enters a first reaction tank, an acid solution or an alkaline solution is added to the first reaction tank, the pH value in the first reaction tank is controlled to be 1-3 by the acid solution, or the pH value in the first reaction tank is controlled to be 12-14 by the alkaline solution, the organic matter in the first reaction tank is converted from a dissolved state or a colloidal state to a suspended state by the acid solution or the alkaline solution, and then a filter aid is added to the first reaction tank;

[0021] Controlling the first filter press mechanism to perform filter press treatment on the reaction liquid from the first reaction tank, and the filtrate after the filter press treatment enters the second reaction tank after the pH value is adjusted to be neutral;

[0022] Adding a modifier into the second reaction tank to remove organic matter, decolorize and remove COD from the filtrate in the second reaction tank, and then adding a filter aid into the second reaction tank to assist filtering;

[0023] Controlling the second filter press mechanism to perform filter press treatment on the reaction liquid from the second reaction tank to obtain a clear and transparent filtrate, and evaporating the filtrate to obtain a crystalline salt;

[0024] The filtrate is controlled to pass through the evaporation water inlet tank for homogenization and then enter the evaporation system for evaporation treatment to obtain crystalline salt.

[0025] The mother liquor evaporation treatment system of the present invention can be used to treat evaporation crystallization mother liquor, and the final filtrate is clear and bright, various organic substances that affect evaporation can be effectively removed, the COD removal rate of the filtrate is higher than 60%, and the filtrate can be re-evaporated to obtain crystallized salt with good particle size and whiteness. The invention can be used to treat evaporation crystallization mother liquor, and the treatment effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0027] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0028] FIG1 is a schematic diagram of a mother liquid evaporation treatment system according to an embodiment of the present invention.

[0029] Description of Reference Numerals

[0030] 10. Mother liquor evaporation treatment system; 100. First reaction tank; 200. First filter press mechanism; 300. Second reaction tank; 400. Second filter press mechanism; 500. Evaporation system; 510. Single steamer; 520. Plate heat exchanger; 530. Vacuum unit; 540. Centrifuge; 550. Centrifuge post-liquid tank; 560. Cold separation tank; 570. Evaporation water inlet tank; 600. Adjustment tank. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In this article, "optionally", "optional", "optional" means optional, that is, it means to be selected from any of the two parallel solutions of "yes" or "no". If there are multiple "optional" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent. In this application, the descriptions such as "optionally contain" and "optionally include" mean "contain or not contain".

[0037] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for a broad range of quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] The embodiment of the present application provides a mother liquor evaporation treatment system to solve at least one of the following problems existing in the treatment of evaporation mother liquor in the traditional technology: (1) The evaporation mother liquor is difficult to evaporate and is prone to sticking to the wall, boiling, and scaling in the evaporation equipment, thereby causing the evaporation energy efficiency to decrease and clogging the tubes of the heat exchanger. (2) The efficiency of removing COD from the evaporation mother liquor through oxidation technology is low and the cost is high. The high salt water is highly corrosive and the equipment cost is high. (3) The mother liquor is dried by a mother liquor drying evaporator or a curing agent is added and finally treated as hazardous waste. The amount of such hazardous waste is large, there are serious hidden dangers, and the treatment cost is high. The mother liquor evaporation treatment system will be described below in conjunction with the accompanying drawings.

[0040] The mother liquor evaporation treatment system 10 provided in the embodiment of the present application is exemplarily shown in FIG1 , which is a schematic diagram of the structure of the mother liquor evaporation treatment system 10 provided in the embodiment of the present application. The mother liquor evaporation treatment system 10 of the present application can be used for mother liquor evaporation treatment, and the filtrate finally obtained is clear and transparent, and various organic substances that affect evaporation can be effectively removed. In order to more clearly illustrate the structure of the mother liquor evaporation treatment system 10, the mother liquor evaporation treatment system 10 will be introduced in conjunction with the accompanying drawings.

[0041] For example, please refer to FIG. 1 , a mother liquor evaporation treatment system 10 includes a first reaction tank 100, a first filter press mechanism 200, a second reaction tank 300, a second filter press mechanism 400 and an evaporation system 500 connected in sequence. In the first reaction tank 100, a filter aid and an acid solution or an alkaline solution are added. The first reaction tank 100 is used to remove organic matter and decolorize the evaporation crystallization mother liquor. The first filter press mechanism 200 is used to perform filter press treatment on the reaction liquid from the first reaction tank 100. Acid solution or alkaline solution, filter aid and modifier can be added to the second reaction tank 300, and the second reaction tank 300 is used to remove organic matter and decolorize the filtrate from the first filter press mechanism 200. The second filter press mechanism 400 is used to perform filter press treatment on the reaction liquid from the second reaction tank 300.

[0042] In some of the embodiments, the inner lining of the first reaction tank 100 has a high temperature resistant anti-corrosion layer, and the high temperature resistant anti-corrosion layer has a withstand temperature of not less than 80°C.

[0043] In some embodiments, a stirring mechanism is provided inside the first reaction tank 100, and the material of the stirring mechanism is 2205 stainless steel. The setting of the stirring mechanism can improve the mixing uniformity of the mother liquid pre-filter aid, acid solution or alkaline solution in the first reaction tank 100.

[0044] In some of the embodiments, the mother liquor evaporation treatment system 100 further includes a regulating tank 600 , and the regulating tank 600 is connected to the first reaction tank 100 to homogenize and uniformly measure the evaporated mother liquor before it enters the first reaction tank 100 .

[0045] Preferably, the dimensions of the first reaction tank 100 are 3.0 m×6.0 m×3.0 m in length, width and height respectively, and the main body material of the first reaction tank 100 is carbon steel.

[0046] In some embodiments, the pH value in the first reaction tank 100 is controlled to be 1-3 by an acid solution. The acid solution includes hydrochloric acid or sulfuric acid.

[0047] In some embodiments, the pH value in the first reaction tank 100 is controlled to be 12-14 by an alkaline solution. The alkaline solution includes NaOH or KOH.

[0048] In some embodiments, the volume of the first reaction tank 100 is not less than 40 m2. The volume of the first reaction tank 100 can be set according to the actual amount of mother liquor to be processed.

[0049] In some embodiments, the volume of the first reaction tank 100 is 40 m2 to 80 m2.

[0050] Preferably, the volume of the first reaction tank 100 is 40 m2.

[0051] In some embodiments, the volume of the second reaction tank 300 is not less than 40 m2. The volume of the second reaction tank 300 can be set according to the actual amount of mother liquid to be processed.

[0052] In some embodiments, the volume of the second reaction tank 300 is 40 m2 to 80 m2.

[0053] Preferably, the volume of the second reaction tank 300 is 40 m2.

[0054] Preferably, the dimensions of the second reaction tank 300 are 3.0 m×6.0 m×3.0 m in length, width and height respectively, and the main body of the second reaction tank 300 is made of carbon steel.

[0055] It should be noted that the size and volume of the first reaction tank 100 and the second reaction tank 300 in the present application can be set according to actual needs.

[0056] In some embodiments, the first filter press mechanism 200 adopts a plate-frame diaphragm filter press. The plate-frame area of ​​the first filter press mechanism 200 is not less than 200 m2, the moisture content of the filter cake after filtration by the first filter press mechanism 200 is ≤65%, and the filter cloth of the first filter press mechanism 200 is made of polyester material with a mesh size of 300-400.

[0057] In some embodiments, the second filter press mechanism 400 adopts a plate-frame diaphragm filter press. The plate-frame area of ​​the second filter press mechanism 400 is not less than 200 m2, the moisture content of the filter cake after filtration by the second filter press mechanism 400 is ≤65%, and the filter cloth of the second filter press mechanism 400 is made of polyester material with a mesh size of 300-400.

[0058] The plate-and-frame diaphragm filter press in this application is a device for solid-liquid separation, which is widely used in the chemical, pharmaceutical, food processing, mining, environmental protection and other industries. The plate-and-frame diaphragm filter press is based on the traditional plate-and-frame filter press, but by adding a diaphragm and a pressure system, its filtering performance and efficiency have been significantly improved. The working principle of the frame diaphragm filter press includes (1) filtration stage: the material is pumped into the filter chamber of the filter press, the liquid in the material is discharged through the filter cloth, and the solid particles are trapped in the filter chamber to form a filter cake. (2) Pressing stage: when the filter chamber is filled with material, the diaphragm expands and squeezes the filter cake, further reducing the water content of the filter cake. (3) Blowing and drying stage (optional): compressed air is used to blow the filter cake to further reduce its moisture content. (4) Unloading stage: after the filtration and pressing process is completed, the filter cake falls off the filter plate or is mechanically scraped off, and then the filter cloth is cleaned and prepared for the next round of operation. The plate and frame membrane filter press used in this application has the following advantages: (1) Efficient dehydration: Through the secondary squeezing of the membrane, a lower filter cake moisture content can be achieved. (2) Automated operation: Modern plate and frame membrane filter presses are usually equipped with an automated control system that can achieve continuous or semi-continuous operation modes. (3) Flexible adaptability: It can handle materials with different characteristics and particle size distributions and is suitable for a variety of industry applications.

[0059] In some embodiments, the evaporation system 500 includes a single steam kettle 510, a plate heat exchanger 520, a vacuum unit 530, a centrifuge 540, a centrifuge after-throwing liquid tank 550 and a cold separation tank 560, wherein the evaporation water inlet tank, the single steam kettle 510, the centrifuge 540, the centrifuge after-throwing liquid tank 550 and the cold separation tank 560 are connected in sequence, the vacuum unit 530 and the plate heat exchanger 520 are connected to the single steam kettle 510 in sequence, and the negative pressure control of the single steam kettle 510 The pressure is -50Kpa~-20Kpa, the single steamer 510 is used to evaporate the filtrate after homogenization and uniformity from the evaporation water inlet tank, the centrifuge 540 is used to centrifuge the evaporation mother liquor after evaporation to obtain crystalline salt, the after-spin liquid after centrifugation of the centrifuge 540 enters the centrifuge after-spin liquid tank 550, the centrifuge after-spin liquid tank 550 regularly discharges the after-spin liquid to the cold precipitation tank 560, and the cold precipitation tank 560 intermittently feeds the after-spin liquid to the centrifuge 540 after solid materials are precipitated.

[0060] In some embodiments, the centrifuge liquid tank 550 is also connected to the adjustment tank 600.

[0061] In some embodiments, the centrifuge post-flushing liquid tank 550 is also connected to the single distillation kettle 510, so that the post-flushing liquid in the centrifuge post-flushing liquid tank 550 can flow back to the single distillation kettle 510 for circulating steaming.

[0062] In some embodiments, the modifier includes a liquid resin, the liquid resin includes a dicyandiamide formaldehyde polycondensation resin and / or a polysilicate flocculant, the dilution concentration of the liquid resin is 10%, the dosage of the liquid resin is 1000 mg / L to 5000 mg / L, the decolorization rate of the liquid resin is not less than 80%, and the COD removal rate of the liquid resin is not less than 60%. The dicyandiamide formaldehyde polycondensation resin is a polymer compound generated by the reaction of dicyandiamide (dicyandiamide) and formaldehyde under specific conditions.

[0063] In some embodiments, the filter aid includes activated carbon and / or diatomaceous earth, etc. The filter aid can adsorb colloidal substances and form a filter cake with a high porosity. For example, when the filter aid includes activated carbon, the particle size of the activated carbon is 0.5 mm to 2 mm, accounting for not less than 85%, the iodine adsorption value of the activated carbon is ≥500 mg / g, and the dosage of the activated carbon is 500 mg / L to 2000 mg / L.

[0064] In the present application, the mother liquor is subjected to the adsorption of the first reaction tank 100 to achieve the removal of organic matter and decolorization treatment, and after the pressure filtration, it is subjected to the adsorption, decolorization and other treatments of the acid solution or alkaline solution, filter aid and modifier in the second reaction tank 300, and finally the pressure filtration is performed again. In the above process, the activated carbon has a very high specific surface area and porous structure, which can effectively adsorb organic pollutants, pigments, odor substances and heavy metal ions and other impurities in the mother liquor, thereby improving the purity of the solution. By removing impurities in the mother liquor, the quality of subsequent products (such as crystallized products) can be improved, the impurity content in the product can be reduced, and the purity and stability can be improved. The mother liquor after the pressure filtration can be further processed to recover the solvent or other valuable components therein, reduce waste, and reduce production costs.

[0065] Removing harmful substances can reduce the impact on the environment, make the treated mother liquor more compliant with emission standards, and help protect the environment. Pre-removing most impurities through activated carbon can reduce the burden of subsequent processing steps (such as evaporation, distillation, and crystallization) and improve the efficiency of the overall process. Filtering using filter press is simple to operate, has a high degree of automation, can be operated continuously or intermittently, and is suitable for large-scale industrial production.

[0066] An embodiment of the present application provides a mother liquid evaporation treatment method.

[0067] The processing object of the present application is evaporation crystallization mother liquor, which is taken from the existing evaporation crystallization system. Since part of the evaporation crystallization mother liquor in the evaporation crystallization system is enriched and the crystallization salt cannot be separated, the evaporation process is difficult to continue. Therefore, this part of the evaporation crystallization mother liquor needs to be discharged. The evaporation crystallization mother liquor is characterized by a saturated salt solution, with a detected TDS of about 400,000 mg / L to 600,000 mg / L, a COD of about 5000 mg / L to 50000 mg / L, and a color that is often yellow and turbid. The evaporation crystallization mother liquor contains many large molecular organic substances that affect evaporation and are difficult to detect under the influence of high salt.

[0068] A mother liquid evaporation treatment method using the mother liquid evaporation treatment system 10 comprises the following steps:

[0069] It should be noted that, in this article, unless otherwise specified, each reaction step can be carried out in the order described herein, or can be carried out in a non-sequential manner. For example, other steps may be included between each reaction step, and the order of the reaction steps may also be appropriately swapped. This can be determined by the technician based on conventional knowledge and experience. Preferably, the reaction method herein is carried out sequentially.

[0070] After being homogenized and uniformly weighed, the evaporation crystallization mother liquor enters the first reaction tank 100, and an acid solution or an alkaline solution is added into the first reaction tank 100, and the pH value in the first reaction tank 100 is controlled to be 1-3 by the acid solution, or the pH value in the first reaction tank 100 is controlled to be 12-14 by the alkaline solution. The organic matter in the first reaction tank 100 is converted from a dissolved state or a colloidal state to a suspended state by the acid solution or the alkaline solution, and then a filter aid is added into the first reaction tank 100, and the organic matter is separated by flocculation precipitation and flotation methods.

[0071] The first filter press mechanism 200 is controlled to perform filter press treatment on the reaction liquid from the first reaction tank 100 , and the filtrate after the filter press treatment enters the second reaction tank 300 after the pH value is adjusted to be neutral.

[0072] A modifier is added into the second reaction tank 300 to remove organic matter, decolorize and remove COD from the filtrate in the second reaction tank 300, and then a filter aid is added into the second reaction tank 300 to assist filtering.

[0073] The second filter press mechanism 400 is controlled to perform filter press treatment on the reaction liquid from the second reaction tank 300 to obtain a clear and transparent filtrate.

[0074] The filtrate is controlled to be homogenized and uniformly distributed after passing through the evaporation water inlet tank and then enters the evaporation system 500 for evaporation treatment to obtain crystallized salt. During the evaporation treatment in the evaporation system 500, the steam passes through the plate heat exchanger 520 and is condensed, and the condensate passes through the vacuum tank to form a secondary condensate and is discharged, and the non-condensable gas enters the vacuum unit 530 for treatment and is discharged. The evaporation mother liquor of the single steamer 510 enters the centrifuge 540 for centrifugation to obtain solid crystallized salt, and the after-spin liquid after centrifugation of the centrifuge 540 enters the centrifuge after-spin liquid tank 550 for storage, and the centrifuge after-spin liquid tank 550 regularly discharges the after-spin liquid to the cold separation tank 560, and the cold separation tank 560 intermittently feeds the centrifuge 540 after the solid-containing material is precipitated from the after-spin liquid.

[0075] Preferably, part of the evaporated mother liquor in the liquid tank 550 after centrifuge can enter the regulating tank 600 for homogenization and quantity adjustment and then undergo the mother liquor evaporation process again.

[0076] Preferably, part of the evaporation mother liquor in the centrifuge liquid tank 550 can enter the single distillation kettle 510, so that part of the liquid after centrifugation can be refluxed to the single distillation kettle 510 for cyclic steam distillation.

[0077] In the above-mentioned mother liquor evaporation treatment method, the evaporated crystallization mother liquor passes through the first reaction tank 100 for acid precipitation or alkali precipitation, and then undergoes coagulation sedimentation or flotation to remove part of the COD in the liquid, and then activated carbon is added and then subjected to the first filter press. After the pH of the filtrate is adjusted to neutral, a modifier such as dicyandiamide formaldehyde condensation resin is added, and then coagulation sedimentation is further used to remove the COD in the liquid, and then activated carbon is added and filtered, and the filtrate can be evaporated to obtain a crystalline salt.

[0078] Example 1

[0079] This embodiment provides a mother liquid evaporation treatment system 10 .

[0080] The mother liquor evaporation treatment system 10 of this embodiment includes a first reaction tank 100, a first filter press mechanism 200, a second reaction tank 300 and a second filter press mechanism 400 connected in sequence. Among them, filter aids and acid solutions can be added into the first reaction tank 100. The dimensions of the first reaction tank 100 are 3.0m×6.0m×3.0m in length, width and height, respectively, and the main body material of the first reaction tank 100 is carbon steel. The inner lining of the first reaction tank 100 has a high-temperature resistant anti-corrosion layer, and the tolerance temperature of the high-temperature resistant anti-corrosion layer is not less than 80°C. A stirring mechanism is provided inside the first reaction tank 100, and the material of the stirring mechanism is 2205 stainless steel. The dimensions of the second reaction tank 300 are 3.0m×6.0m×3.0m in length, width and height, respectively, and the main body material of the second reaction tank 300 is carbon steel.

[0081] The first filter press mechanism 200 uses a plate-frame diaphragm filter press. The plate frame area of ​​the first filter press mechanism 200 is 200 m2, and the filter cloth of the first filter press mechanism 200 is made of 300-mesh polyester. The second filter press mechanism 400 uses a plate-frame diaphragm filter press. The plate frame area of ​​the second filter press mechanism 400 is 200 m2, and the filter cloth of the second filter press mechanism 400 is made of 300-mesh polyester.

[0082] The mother liquor evaporation treatment was carried out using the mother liquor evaporation treatment system 10. Before the treatment, the TDS of the evaporated crystallization mother liquor was 419800 mg / L and the COD was 5612 mg / L.

[0083] A mother liquid evaporation treatment method using the mother liquid evaporation treatment system 10 comprises the following steps:

[0084] S1. After the evaporation and crystallization mother liquor is homogenized in the adjustment tank, it enters the first reaction tank 100, hydrochloric acid is added into the first reaction tank 100, and the pH value in the first reaction tank 100 is controlled to be 1 by the hydrochloric acid, and the organic matter in the first reaction tank 100 is converted from a dissolved state and a colloidal state to a suspended state by the acid solution, and then activated carbon is added into the first reaction tank 100, wherein the particle size of the activated carbon is 0.5 mm, accounting for 85%, the iodine adsorption value of the activated carbon is ≥500 mg / g, and the dosage of the activated carbon is 500 mg / L, and the organic matter is separated by flocculation precipitation and flotation method.

[0085] S2, controlling the first filter press mechanism 200 to perform filter press treatment on the reaction liquid from the first reaction tank 100, controlling the moisture content of the filter cake after the filter press by the first filter press mechanism 200 to be ≤65%, and the filtrate after the filter press treatment enters the second reaction tank 300 after the pH value is adjusted to neutral.

[0086] S3. Add dicyandiamide formaldehyde polycondensation resin to the second reaction tank 300 to remove organic matter, decolorize and remove COD from the filtrate in the second reaction tank 300. The dilution concentration of dicyandiamide formaldehyde polycondensation resin is 10%, the dosage of liquid resin is 1000 mg / L, the decolorization rate is 80%, and the COD removal rate is 60%. Then add activated carbon to the second reaction tank 300 for filtration assistance. The particle size of the activated carbon is 0.5 mm, accounting for 85%, the iodine adsorption value of the activated carbon is ≥500 mg / g, and the dosage of the activated carbon is 1000 mg / L.

[0087] S4, control the second filter press mechanism 400 to filter the reaction liquid from the second reaction tank 300, and control the moisture content of the filter cake after the second filter press mechanism 400 is ≤65%, so as to obtain a clear and transparent filtrate. After testing, the TDS after treatment is about 421200 mg / L, and the COD is 2144 mg / L.

[0088] S5. The clear filtrate obtained in step S4 is homogenized and uniformly distributed in the evaporation water inlet tank and then enters the single steam kettle 510 for evaporation treatment to obtain crystallized salt. The negative pressure of the single steam kettle 510 is controlled to be -50Kpa. The steam of the single steam kettle 510 is condensed after passing through the plate heat exchanger 520, and the condensate is discharged after passing through the vacuum tank to form a secondary condensate, and the non-condensable gas enters the vacuum unit 530 for treatment and then discharged. The evaporated mother liquor of the single steam kettle 510 enters the centrifuge 540 for centrifugation to obtain solid crystallized salt, and the after-spin liquid after the centrifugation of the centrifuge 540 enters the centrifuge after-spin liquid tank 550 for storage, and the centrifuge after-spin liquid tank 550 regularly discharges the after-spin liquid to the cold analysis tank 560, and the cold analysis tank 560 intermittently feeds the centrifuge 540 after the solid-containing material is precipitated from the after-spin liquid.

[0089] S6. Part of the evaporated mother liquor in the liquid tank 550 after centrifugation can enter the regulating tank 600 for homogenization and quantity adjustment and then re-perform the mother liquor evaporation process.

[0090] S7. Part of the evaporation mother liquid in the centrifuge liquid tank 550 can enter the single distillation kettle 510, so that part of the liquid after centrifugation can flow back to the single distillation kettle 510 for cyclic distillation.

[0091] Example 2

[0092] This embodiment provides a mother liquid evaporation treatment system 10 .

[0093] The mother liquor evaporation treatment system 10 of this embodiment includes a first reaction tank 100, a first filter press mechanism 200, a second reaction tank 300 and a second filter press mechanism 400 connected in sequence. Among them, filter aids and alkaline solutions can be added into the first reaction tank 100. The dimensions of the first reaction tank 100 are 3.0m×6.0m×3.0m in length, width and height, respectively, and the main body material of the first reaction tank 100 is carbon steel. The lining of the first reaction tank 100 has a high-temperature resistant anti-corrosion layer, and the tolerance temperature of the high-temperature resistant anti-corrosion layer is not less than 80°C. A stirring mechanism is provided inside the first reaction tank 100, and the material of the stirring mechanism is 2205 stainless steel. The dimensions of the second reaction tank 300 are 3.0m×6.0m×3.0m in length, width and height, respectively, and the main body material of the second reaction tank 300 is carbon steel.

[0094] The first filter press mechanism 200 uses a plate-frame diaphragm filter press. The plate frame area of ​​the first filter press mechanism 200 is 200 m2, and the filter cloth of the first filter press mechanism 200 is made of polyester with a mesh size of 400. The second filter press mechanism 400 uses a plate-frame diaphragm filter press. The plate frame area of ​​the second filter press mechanism 400 is 200 m2, and the filter cloth of the second filter press mechanism 400 is made of polyester with a mesh size of 400.

[0095] The mother liquor evaporation treatment system 10 is used to carry out the mother liquor evaporation treatment. The TDS of the evaporated crystallization mother liquor is about 411200 mg / L, and the COD is 9365 mg / L.

[0096] A mother liquid evaporation treatment method using the mother liquid evaporation treatment system 10 comprises the following steps:

[0097] S1. After the evaporation and crystallization mother liquor is homogenized in the adjustment tank, it enters the first reaction tank 100, and sodium hydroxide is added into the first reaction tank 100. The pH value in the first reaction tank 100 is controlled to be 13 by sodium hydroxide. The organic matter in the first reaction tank 100 is converted from a dissolved state and a colloidal state to a suspended state by an alkaline solution. Then, activated carbon is added into the first reaction tank 100. The particle size of the activated carbon is 2 mm, accounting for 85%. The iodine adsorption value of the activated carbon is ≥500 mg / g, and the dosage of the activated carbon is 2000 mg / L. The organic matter is separated by flocculation precipitation and flotation.

[0098] S2, controlling the first filter press mechanism 200 to perform filter press treatment on the reaction liquid from the first reaction tank 100, controlling the moisture content of the filter cake after the filter press by the first filter press mechanism 200 to be ≤65%, and the filtrate after the filter press treatment enters the second reaction tank 300 after the pH value is adjusted to neutral.

[0099] S3. Add dicyandiamide formaldehyde polycondensation resin to the second reaction tank 300 to remove organic matter, decolorize and remove COD from the filtrate in the second reaction tank 300. The dilution concentration of dicyandiamide formaldehyde polycondensation resin is 10%, the dosage of liquid resin is 5000 mg / L, the decolorization rate is 80%, and the COD removal rate is 60%. Then add activated carbon to the second reaction tank 300 for filtration assistance. The particle size of the activated carbon is 2 mm, accounting for 85%, the iodine adsorption value of the activated carbon is ≥500 mg / g, and the dosage of the activated carbon is 2000 mg / L.

[0100] S4, control the second filter press mechanism 400 to filter the reaction liquid from the second reaction tank 300, control the moisture content of the filter cake after the second filter press mechanism 400 to be ≤65%, and obtain a clear and transparent filtrate. After testing, the TDS after treatment is about 415200 mg / L, and the COD is 3446 mg / L.

[0101] S5. The clear filtrate obtained in step S4 is homogenized and uniformly distributed in the evaporation water inlet tank and then enters the single steam kettle 510 for evaporation treatment to obtain crystallized salt. The negative pressure of the single steam kettle 510 is controlled to be -20Kpa. The steam of the single steam kettle 510 is condensed after passing through the plate heat exchanger 520, and the condensate is discharged after passing through the vacuum tank to form a secondary condensate, and the non-condensable gas enters the vacuum unit 530 for treatment and then discharged. The evaporated mother liquor of the single steam kettle 510 enters the centrifuge 540 for centrifugation to obtain solid crystallized salt, and the after-spin liquid after the centrifugation of the centrifuge 540 enters the centrifuge after-spin liquid tank 550 for storage, and the centrifuge after-spin liquid tank 550 regularly discharges the after-spin liquid to the cold analysis tank 560, and the cold analysis tank 560 intermittently feeds the centrifuge 540 after the solid-containing material is precipitated from the after-spin liquid.

[0102] S6. Part of the evaporated mother liquor in the liquid tank 550 after centrifugation can enter the regulating tank 600 for homogenization and quantity adjustment and then re-perform the mother liquor evaporation process.

[0103] S7. Part of the evaporation mother liquid in the centrifuge liquid tank 550 can enter the single distillation kettle 510, so that part of the liquid after centrifugation can flow back to the single distillation kettle 510 for cyclic distillation.

[0104] In summary, the mother liquor evaporation treatment system 10 of the present invention can be used to treat evaporation crystallization mother liquor, and the final filtrate is clear and bright, various organic substances that affect evaporation can be effectively removed, the COD removal rate of the filtrate is higher than 70%, and the filtrate can be re-evaporated to obtain crystallized salt with good particle size and whiteness. The present invention can be used to treat evaporation crystallization mother liquor with good treatment effect.

[0105] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0106] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A mother liquor evaporation treatment system, characterized in that: The invention comprises a first reaction tank, a first filter press mechanism, a second reaction tank, a second filter press mechanism, an evaporation water inlet tank and an evaporation system which are connected in sequence, wherein the first reaction tank can be added with a filter aid and an acid solution or an alkaline solution, the first reaction tank is used for removing organic matter and decolorizing the evaporation crystallization mother liquor, the first filter press mechanism is used for performing filter press treatment on the reaction liquid from the first reaction tank, the second reaction tank can be added with an acid solution or an alkaline solution, a filter aid and a modifier, the second reaction tank is used for removing organic matter and decolorizing the filtrate from the first filter press mechanism, the second filter press mechanism is used for performing filter press treatment on the reaction liquid from the second reaction tank, the evaporation water inlet tank is used for homogenizing and quantifying the filtrate from the second filter press mechanism, and the evaporation system is used for evaporating the filtrate after homogenization and quantification from the evaporation water inlet tank to obtain crystalline salt.

2. The mother liquor evaporation treatment system according to claim 1, characterized in that: The inner lining of the first reaction tank has a high temperature resistant anti-corrosion layer, and the high temperature resistant anti-corrosion layer has a tolerance temperature of not less than 80°C; And / or, a stirring mechanism is provided inside the first reaction tank; And / or, the mother liquor evaporation treatment system further comprises a regulating tank, and the regulating tank is connected to the first reaction tank so as to homogenize and uniformly distribute the evaporated mother liquor before the evaporated mother liquor enters the first reaction tank.

3. The mother liquor evaporation treatment system according to claim 1, characterized in that: Controlling the pH value in the first reaction tank to be 1-3 by the acid solution; And / or, the pH value in the first reaction tank is controlled to be 12-14 by the alkaline solution.

4. The mother liquor evaporation treatment system according to any one of claims 1 to 3, characterized in that: The first filter press mechanism adopts a plate and frame diaphragm filter press, the moisture content of the filter cake after filtration by the first filter press mechanism is ≤65%, and the filter cloth of the first filter press mechanism is made of polyester material with a mesh size between 300 and 400.

5. The mother liquor evaporation treatment system according to any one of claims 1 to 3, characterized in that: The second filter press mechanism adopts a plate and frame diaphragm filter press, the moisture content of the filter cake after filtration by the second filter press mechanism is ≤65%, and the filter cloth of the second filter press mechanism is made of polyester material with a mesh size between 300 and 400.

6. The mother liquor evaporation treatment system according to any one of claims 1 to 3, characterized in that: The evaporation system includes a single steam kettle, a plate heat exchanger, a vacuum unit, a centrifuge, a centrifuge post-flushing tank and a cold analysis tank, wherein the evaporation water inlet tank, the single steam kettle, the centrifuge, the centrifuge post-flushing tank and the cold analysis tank are connected in sequence, the vacuum unit and the plate heat exchanger are connected to the single steam kettle in sequence, the negative pressure of the single steam kettle is controlled to be -50Kpa~-20Kpa, the single steam kettle is used to evaporate the filtrate after homogenization and uniformity from the evaporation water inlet tank, the centrifuge is used to centrifuge the evaporated mother liquor after evaporation to obtain crystalline salt, the post-flushing liquid after centrifugation of the centrifuge enters the centrifuge post-flushing tank, the centrifuge post-flushing tank regularly discharges the post-flushing liquid to the cold analysis tank, and the cold analysis tank intermittently feeds the post-flushing liquid to the centrifuge after solid materials are precipitated.

7. The mother liquor evaporation treatment system according to claim 6, characterized in that: The centrifuge post-spin liquid tank is also connected to the regulating tank to enable part of the concentrated post-spin liquid to flow back to the regulating tank for further pretreatment; And / or, the centrifuge post-flushing liquid tank is also connected to the single distillation kettle, so that the post-flushing liquid in the centrifuge post-flushing liquid tank can flow back to the single distillation kettle for cyclic steaming.

8. The mother liquid evaporation treatment system according to any one of claims 1 to 3 and 7, characterized in that: The modifier includes a liquid resin, and the liquid resin includes a dicyandiamide formaldehyde condensation resin. The dilution concentration of the modifier is 10%, the dosage of the modifier is 1000 mg / L to 5000 mg / L, the decolorization rate of the modifier is not less than 80%, and the COD removal rate of the liquid resin is not less than 60%.

9. The mother liquid evaporation treatment system according to any one of claims 1 to 3 and 7, characterized in that: The filter aid is one or more of activated carbon, diatomaceous earth, and perlite, and the dosage of the filter aid is 500 mg / L to 2000 mg / L.

10. A mother liquid evaporation treatment method using the mother liquid evaporation treatment system according to any one of claims 1 to 9, characterized in that: The steps include: After being homogenized and uniformly weighed, the evaporation crystallization mother liquor enters a first reaction tank, an acid solution or an alkaline solution is added to the first reaction tank, the pH value in the first reaction tank is controlled to be 1-3 by the acid solution, or the pH value in the first reaction tank is controlled to be 12-14 by the alkaline solution, the organic matter in the first reaction tank is converted from a dissolved state or a colloidal state to a suspended state by the acid solution or the alkaline solution, and then a filter aid is added to the first reaction tank; Controlling the first filter press mechanism to perform filter press treatment on the reaction liquid from the first reaction tank, and the filtrate after the filter press treatment enters the second reaction tank after the pH value is adjusted to be neutral; Adding a modifier into the second reaction tank to remove organic matter, decolorize and remove COD from the filtrate in the second reaction tank, and then adding a filter aid into the second reaction tank to assist filtering; Controlling the second filter press mechanism to perform filter press treatment on the reaction liquid from the second reaction tank to obtain a clear and transparent filtrate; The filtrate is controlled to pass through the evaporation water inlet tank for homogenization and then enter the evaporation system for evaporation treatment to obtain crystalline salt.

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