Oily sewage purifying agent system and preparation method thereof

Abstract

The invention provides an oily sewage purifier system and a preparation method thereof, and belongs to the field of sewage treatment. The oily sewage purifying agent system is composed of a composite coagulant and an organic polymeric flocculant. Wherein the composite coagulant is prepared from the following components in parts by mass: 20-25 parts of polyferric sulfate; 25 to 30 parts of concentrated sulfuric acid; 3-5 parts of aluminum sulfate; 2-5 parts of ferric trichloride; 3 to 5 parts of poly dimethyl diallyl ammonium chloride; the organic polymeric flocculant is a cationic polyacrylamide aqueous solution. By adopting the multi-component coagulant, the components and the synergistic effect of the components can be utilized. Colloids in the sewage lose stability by adding a composite coagulant, a particle condensation phenomenon is generated, tiny flocs are formed, then cationic polyacrylamide is added, the tiny flocs are combined into dense flocs, the treatment effect is improved, and various organic wastes in the sewage are effectively flocculated and removed.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and in particular to an oily sewage purifier system and a preparation method thereof. Background Art

[0002] The water quality characteristics of heavy oil wastewater are the reasons for the difficulty in oil-water separation and the poor effects of oil and suspended solids removal. Compared with conventional wastewater, oil and water in heavy oil wastewater are prone to form stable water-in-oil emulsions or water-in-oil-in-water multilayer emulsions, which makes heavy oil wastewater seriously emulsified and increases the difficulty of demulsification and oil removal in heavy oil wastewater; the density difference between oil and water in heavy oil wastewater is small, which increases the difficulty of gravity separation of oil and water. In order to achieve the purpose of reinjection or external discharge of heavy oil wastewater, the research and development of high-efficiency water purifiers is the basis and key to heavy oil wastewater treatment.

[0003] Due to the complex composition of heavy oil wastewater, it is difficult for the water purifiers in the existing technology to remove all organic wastes. Therefore, it is urgent to develop a water purifier that can achieve good water purification effects. Summary of the invention

[0004] The present application provides an oily wastewater purifier system and a preparation method thereof, which adopts a multi-component coagulant and utilizes the components themselves and their synergistic effects to solve the technical problem of poor water purification effect of existing oily wastewater purifiers.

[0005] In the first aspect, the present application provides an oily wastewater purifier system, which is composed of a composite coagulant and an organic polymer flocculant; wherein:

[0006] The composite coagulant is composed of the following components in parts by mass: 20 to 25 parts of polyferric sulfate; 25 to 30 parts of concentrated sulfuric acid; 3 to 5 parts of aluminum sulfate; 2 to 5 parts of ferric chloride; 3 to 5 parts of polydimethyldiallylammonium chloride; and the balance is water. The organic polymer flocculant is a cationic polyacrylamide aqueous solution.

[0007] Optionally, the composite coagulant is composed of the following components in parts by mass: 25 parts of polyferric sulfate; 30 parts of concentrated sulfuric acid; 5 parts of aluminum sulfate; 5 parts of ferric chloride; 5 parts of polydimethyldiallylammonium chloride; and 30 parts of water, and the organic polymer flocculant is a cationic polyacrylamide aqueous solution with a mass concentration of 1%.

[0008] Optionally, the mass fraction of iron in the polyferric sulfate is 19% to 21%.

[0009] Optionally, the cationic degree of the cationic polyacrylamide is 45-55.

[0010] In a second aspect, the present application provides a method for preparing the oily wastewater purification agent system according to any one embodiment of the first aspect, the method comprising:

[0011] Aluminum sulfate and polydimethyldiallylammonium chloride are dissolved in water, and then sequentially mixed with polyferric sulfate, ferric chloride and concentrated sulfuric acid to obtain a composite coagulant;

[0012] Cationic polyacrylamide is added into water to obtain an organic polymer flocculant.

[0013] In a third aspect, the present application provides a method for purifying oily wastewater, wherein the oily wastewater purifier system described in any one of the first aspects is used as a reagent for treating oily wastewater, and the method comprises:

[0014] The composite coagulant is added to the oily wastewater to generate micro flocs;

[0015] Adding the organic polymer flocculant to the oily wastewater containing micro flocs to combine the micro flocs to form dense flocs;

[0016] The dense flocs are separated by air flotation to obtain purified oily wastewater.

[0017] Optionally, relative to the volume of 1 L of the oily wastewater, the added volume of the composite coagulant is 0.5 ml to 1.5 ml.

[0018] Optionally, relative to the volume of 1L of the oily wastewater, the added volume of the organic polymer flocculant is 2ml to 4ml.

[0019] Optionally, the sedimentation time in the flotation separation is 1 h to 4 h.

[0020] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0021] The application adopts a multi-component coagulant to utilize the components themselves and their synergistic effects. By adding a coagulant, the colloid in the sewage loses stability, produces a particle coagulation phenomenon, forms tiny flocs, and then adds cationic polyacrylamide to combine the tiny flocs into dense flocs to improve the treatment effect, effectively flocculating and removing various organic wastes in the sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0024] Figure 1 A schematic flow chart of a method for preparing an oily wastewater purification agent system provided in an embodiment of the present application;

[0025] Figure 2 This is a comparison chart of the suspended solids removal rates after treating oily wastewater by the water purification agent system of the embodiment of the present application and the comparative example. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0028] In addition, in the description of the specification of the present application, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second", etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "the following at least one item (items)" or similar expressions refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0030] In the first aspect, the present application provides an oily wastewater purifier system, which is composed of a composite coagulant and an organic polymer flocculant; wherein:

[0031] The composite coagulant is composed of the following components in parts by mass: 20 to 25 parts of polyferric sulfate; 25 to 30 parts of sulfuric acid; 3 to 5 parts of aluminum sulfate; 2 to 5 parts of ferric chloride; 3 to 5 parts of polydimethyldiallylammonium chloride; and the balance is water. The organic polymer flocculant is a cationic polyacrylamide aqueous solution.

[0032] The application adopts a multi-component coagulant to utilize the components themselves and their synergistic effects. By adding a coagulant, the colloid in the sewage loses stability, produces a particle coagulation phenomenon, forms tiny flocs, and then adds cationic polyacrylamide to combine the tiny flocs into dense flocs to improve the treatment effect, effectively flocculating and removing various organic wastes in the sewage.

[0033] In the embodiment of the present application, the positive effect of controlling the amount of polyferric sulfate to 20 to 25 parts is as follows: after the polyferric sulfate is dissolved, a variety of polymerized ions are generated, which have the effects of rapid miscibility, charge neutralization, hydrolysis bridging, coagulation precipitation and adsorption, and are mainly used as flocculants and precipitants in water treatment to remove suspended matter and pollutants. When the amount of polyferric sulfate added is less than 20 parts, the treatment effect is reduced, the reaction rate is reduced, the stability of the solution is reduced, and the flocs formed are easy to decompose; when the amount added is higher than 25 parts, the excessive amount of addition causes turbidity in the water quality, the alum flowers turn up, the amount of sludge after sewage treatment increases, and the cost increases. The polyferric sulfate can be 20 parts, 21 parts, 22 parts, 24 parts, 25 parts, etc.

[0034] The positive effect of controlling sulfuric acid to 25 to 30 parts: sulfuric acid has a good demulsification effect and can be used as a pH regulator. Polyferric sulfate has the best effect in treating oily wastewater in the pH range of 5.5-6.5. Combined with the alkaline characteristics of oily wastewater, adding sulfuric acid in an appropriate amount can improve the wastewater treatment effect. When the sulfuric acid dosage is less than 25 parts, the composite coagulant cannot achieve the best effect in treating oily wastewater; when the sulfuric acid dosage is higher than 30 parts, the pH of the treated wastewater is lower than 6.5, which is not conducive to the subsequent biochemical process and the wastewater discharge index requirement of pH 6-9. The sulfuric acid can be 25 parts, 26 parts, 27 parts, 28 parts, 30 parts, etc.

[0035] The positive effects of controlling 3 to 5 parts of polydimethyldiallyl ammonium chloride and 3 to 5 parts of aluminum sulfate: the relative molecular mass of polydimethyldiallyl ammonium chloride is high and adjustable, the product has good stability, strong adsorption and bridging ability for colloidal substances in water, and good flocculation effect. When used alone, there are the disadvantages of high water treatment cost caused by high price of the agent and narrow range of optimal dosage. Aluminum sulfate and polydimethyldiallyl ammonium chloride are mixed in a ratio of 1:1 and used to enhance the water treatment effect, broaden the scope of use of the agent, and reduce the cost of use. It can improve the deturbidity and decolorization effects. The polydimethyldiallyl ammonium chloride can be 3 parts, 4 parts, 5 parts, etc., and the aluminum sulfate can be 3 parts, 4 parts, 5 parts, etc.

[0036] The positive effect of controlling the ferric chloride to 2 to 5 parts: the main function of the ferric chloride in the composite coagulant is to react chemically with the suspended matter and colloid in the sewage to form larger particles, thereby condensing into precipitated substances and removing them from the sewage. When the ferric chloride dosage is less than 2 parts, the flocs formed are small and loose; when the dosage is greater than 5 parts, the flocculation effect is reduced. The ferric chloride can be 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0037] In some embodiments, the composite coagulant is composed of the following components in parts by mass: 25 parts of polyferric sulfate; 30 parts of sulfuric acid; 5 parts of aluminum sulfate; 5 parts of ferric chloride; 5 parts of polydimethyldiallylammonium chloride; and 30 parts of water, and the organic polymer flocculant is a cationic polyacrylamide aqueous solution with a mass concentration of 1%.

[0038] In some embodiments, the mass fraction of iron in the polyferric sulfate is 19% to 21%.

[0039] The positive effect of controlling the mass fraction of iron in polyferric sulfate to 19% to 21% is that the iron content is the main indicator of the flocculation effect of polyferric sulfate, and the mass fraction can be 19%, 20%, 21%, etc.

[0040] In some embodiments, the cationic polyacrylamide has a cationicity of 45-55.

[0041] The positive effect of controlling the cationic degree of cationic polyacrylamide to 45-55: as the cationic degree increases, the sewage treatment effect improves. When the cationic degree is above 55, the treatment effect is not significantly improved, and the cost is high. Therefore, the cationic degree range of 45-55 is selected. The cationic degree of the cationic polyacrylamide can be 45, 47, 50, 52, 55, etc.

[0042] In a second aspect, the present application provides a method for preparing the oily wastewater purification agent system according to any one embodiment of the first aspect, the method comprising:

[0043] S11, dissolving aluminum sulfate and polydimethyldiallylammonium chloride in water, and then sequentially mixing with polyferric sulfate, ferric chloride and concentrated sulfuric acid to obtain a composite coagulant;

[0044] S12. Add cationic polyacrylamide into water to obtain an organic polymer flocculant.

[0045] In a third aspect, the present application provides a method for purifying oily wastewater, wherein the water purifier system described in any one of the embodiments of the first aspect is used as a reagent for treating oily wastewater, and the method comprises:

[0046] S21, adding the composite coagulant to the oily wastewater to generate micro flocs;

[0047] S22, adding the organic polymer flocculant to the oily wastewater containing micro flocs, so that the micro flocs are combined to form dense flocs;

[0048] S23, separating the dense flocs by flotation to obtain purified oily wastewater.

[0049] In some embodiments, the added volume of the composite coagulant is 0.5 ml to 1.5 ml relative to the volume of 1 L of the oily wastewater. The added volume of the composite coagulant can be 0.5 ml, 0.8 ml, 1.1 ml, 1.3 ml, 1.5 ml, etc.

[0050] In some embodiments, relative to the volume of 1 L of the oily wastewater, the added volume of the organic polymer flocculant is 2 ml to 4 ml.

[0051] Relative to the oily wastewater with a volume of 1L, controlling the added volume of the organic polymer flocculant to 2ml to 4ml has the positive effects: if the dosage of the polymer flocculant is less than 2ml, the flocs are small, unstable, and the sedimentation rate is slow; if the dosage is more than 4ml, it is too large, contributing to COD, the wastewater is emulsified, and the viscosity increases.

[0052] In some embodiments, the sedimentation time in the flotation separation is 1 h to 4 h.

[0053] The positive effect of controlling the settling time in air flotation separation to 1 hour to 4 hours is that if the time is shorter than 1 hour, the flocs cannot be completely settled. The settling time in air flotation separation can be 1 hour, 2 hours, 3 hours, 4 hours, etc.

[0054] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0055] The components and weight percentages of the composite coagulant in the oily wastewater purification agent system in the embodiments and comparative examples are shown in Table 1.

[0056] Table 1 Components and weight fractions of composite coagulants in the examples and comparative examples

[0057]

[0058]

[0059] Based on the components and mass fractions of the above-mentioned composite coagulant and the organic polymer flocculant, the embodiment of the present application provides a method for purifying oily wastewater, the method comprising:

[0060] S211, adding the composite coagulant to the oily sewage to generate micro flocs, the designed flow rate of the oily sewage is 100 L / h;

[0061] S221, adding the organic polymer flocculant to the oily wastewater containing micro flocs, so that the micro flocs are combined to form dense flocs, wherein the ion degree of the cationic polyacrylamide is 50%;

[0062] S231. Separating the dense flocs by flotation to obtain purified oily wastewater. The main process parameters are shown in Table 2.

[0063] Table 2 Main process parameters in oily wastewater purification

[0064]

[0065]

[0066] The indicators of the oily wastewater of the embodiment and the comparative example before and after treatment were tested, and the results are shown in Table 3.

[0067] Table 3 Effect of water purification system on oily wastewater

[0068]

[0069] From Table 3 and Figure 2 It can be seen that by comparing Example 2 with Comparative Examples 1, 2, and 3, it is shown that polyferric sulfate, aluminum sulfate, and ferric chloride, the three inorganic flocculants, have a synergistic effect; by comparing Example 2 with Comparative Examples 4 and 5, it is shown that the inorganic flocculant and polydimethyldiallylammonium chloride have a synergistic effect; by comparing Example 2 with Comparative Examples 6 and 7, it is shown that the composite coagulant and the organic polymer flocculant have a synergistic effect. By comparing Example 2 with Comparative Example 8, it is shown that by adding the composite coagulant first and then the organic polymer flocculant, the purification effect of oily wastewater can be improved.

[0070] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A water purification agent system for oily wastewater, characterized in that: The oily wastewater purifier system is composed of a composite coagulant and an organic polymer flocculant; wherein: The composite coagulant is composed of the following components in parts by mass: 20 to 25 parts of polyferric sulfate; 25 to 30 parts of concentrated sulfuric acid; 3 to 5 parts of aluminum sulfate; 2 to 5 parts of ferric chloride; 3 to 5 parts of polydimethyldiallylammonium chloride; and the balance is water. The organic polymer flocculant is a cationic polyacrylamide aqueous solution.

2. The oily wastewater purification agent system according to claim 1, characterized in that: The composite coagulant is composed of the following components in parts by mass: 25 parts of polyferric sulfate; 30 parts of concentrated sulfuric acid; 5 parts of aluminum sulfate; 5 parts of ferric chloride; 5 parts of polydimethyldiallylammonium chloride; and 30 parts of water. The organic polymer flocculant is a cationic polyacrylamide aqueous solution with a mass concentration of 1%.

3. The oily wastewater purification agent system according to claim 1, characterized in that: The mass fraction of iron in the polyferric sulfate is 19% to 21%.

4. The oily wastewater purification agent system according to claim 1, characterized in that: The cationic degree of the cationic polyacrylamide is 45-55.

5. A method for preparing the oily wastewater purifier system according to any one of claims 1 to 4, characterized in that: The method comprises: Aluminum sulfate and polydimethyldiallylammonium chloride are dissolved in water, and then sequentially mixed with polyferric sulfate, ferric chloride and concentrated sulfuric acid to obtain a composite coagulant; Cationic polyacrylamide is added into water to obtain an organic polymer flocculant.

6. A method for purifying oily wastewater, characterized in that: The water purifier system according to any one of claims 1 to 4 is used as a reagent for treating oily wastewater, and the method comprises: Adding the composite coagulant to oily wastewater to generate micro flocs; Adding the organic polymer flocculant to the oily wastewater containing micro flocs to combine the micro flocs to form dense flocs; The dense flocs are separated by air flotation to obtain purified oily wastewater.

7. The method according to claim 6, characterized in that Relative to the volume of 1L of the oily wastewater, the volume of the composite coagulant is 0.5ml-1.5ml.

8. The method according to claim 6, characterized in that Relative to the volume of 1L of the oily wastewater, the volume of the organic polymer flocculant is 2ml-4ml.

9. The method according to claim 6, characterized in that The sedimentation time in the flotation separation is 1 h to 4 h.

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