阅读说明：本技术 一种炼化污水处理用复合絮凝剂及炼化污水的处理方法 (Composite flocculant for treating refinery sewage and treatment method of refinery sewage ) 是由 王伟 蒋鹏程 于 2018-09-06 设计创作，主要内容包括：本发明提供一种炼化污水处理用复合絮凝剂及炼化污水的处理方法,其中该炼化污水处理用复合絮凝剂包括如下重量份的组分：铝盐8～15份、锌盐6～10份、有机絮凝剂0.02～0.05份、有机络合剂3～4份、水70～85份和无机强酸,其中无机强酸在炼化污水处理用复合絮凝剂中的浓度为0.025～0.085mol/100g。本发明提供的炼化污水处理用复合絮凝剂,解决了单一有机絮凝剂絮体松散的问题,在处理炼化污水时,具有絮凝效率高、絮体较大且密实、投加量少和成本低等优势。(The invention provides a composite flocculant for treating refining sewage and a treatment method of the refining sewage, wherein the composite flocculant for treating the refining sewage comprises the following components in parts by weight: 8-15 parts of aluminum salt, 6-10 parts of zinc salt, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent, 70-85 parts of water and strong inorganic acid, wherein the concentration of the strong inorganic acid in the composite flocculant for treating the refined sewage is 0.025-0.085 mol/100 g. The composite flocculant for treating the refining sewage solves the problem of loose flocs of a single organic flocculant, and has the advantages of high flocculation efficiency, larger and compact flocs, small addition amount, low cost and the like when the refining sewage is treated.)

1. The composite flocculant for treating the refining sewage is characterized by comprising the following components in parts by weight:

8-15 parts of aluminum salt, 6-10 parts of zinc salt, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent, 70-85 parts of water and strong inorganic acid, wherein the concentration of the strong inorganic acid in the composite flocculant for treating the refinery sewage is 0.025-0.085 mol/100 g.

2. The composite flocculant for treating refining wastewater according to claim 1, wherein the inorganic strong acid is hydrochloric acid, nitric acid, or sulfuric acid.

3. The composite flocculant for refining and chemical wastewater treatment according to claim 1 or 2, which is characterized by comprising the following components in parts by weight based on 100 parts by weight of the total mass of the composite flocculant for refining and chemical wastewater treatment:

8-15 parts of aluminum salt, 6-10 parts of zinc salt, 1-3 parts of concentrated hydrochloric acid, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent and the balance of water; or

8-15 parts of aluminum salt, 6-10 parts of zinc salt, 3-8 parts of concentrated sulfuric acid, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent and the balance of water; or

8-15 parts of aluminum salt, 6-10 parts of zinc salt, 2-5 parts of concentrated nitric acid, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent and the balance of water.

4. The composite flocculant for treating refinery-related wastewater according to claim 1, wherein the organic flocculant is polyacrylamide and has a molecular weight of 1000 ten thousand or more.

5. The composite flocculant for treating refining wastewater according to claim 1, wherein the organic complexing agent is triethanolamine and/or thiourea.

6. A preparation method of a composite flocculant for treating refining sewage is characterized by comprising the following steps:

dissolving 8-15 parts by weight of aluminum salt and 6-10 parts by weight of zinc salt in an aqueous solution of strong inorganic acid to obtain a first solution;

dissolving 0.02-0.05 part by weight of organic flocculant in water, and then mixing with 3-4 parts by weight of complexing agent to obtain a second solution;

mixing the first solution and the second solution, and then aging to obtain the composite flocculant for the refining sewage treatment;

wherein the weight part of water in the composite flocculant for treating the refining and chemical wastewater is 70-85, and the concentration of inorganic strong acid in the composite flocculant for treating the refining and chemical wastewater is 0.025-0.085 mol/100 g.

7. The method according to claim 6, wherein the aging is performed at 20-30 ℃ for 2-10 hours.

8. The method according to claim 6 or 7, wherein the mass ratio between the water in the first solution and the water in the second solution is 1: 1.5 to 2.5.

9. A method for treating refinery sewage, which is characterized by comprising the following steps: the composite flocculant for treating the refining wastewater, which is disclosed by any one of claims 1 to 5, is added to the refining wastewater, wherein the addition amount of the composite flocculant for treating the refining wastewater is 0.8-2.4 mg/L.

10. The treatment method according to claim 9, wherein the oil content of the refinery-derived wastewater is 20 to 150mg/L, the conductivity is 100 to 2000 μ s/cm, and the turbidity is not more than 100 NTU.

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a composite flocculant for treating refining sewage and a treatment method of the refining sewage.

Background

Along with the development of the petroleum industry and the continuous expansion of oil refining capacity in China, the discharge amount of refining sewage is increased. The refining and chemical sewage has the characteristics of high oil content, high salt content, high COD and the like, and the main pollutants of the refining and chemical sewage are suspended oil, emulsified oil, various suspended matters, salts, partially soluble organic matters and the like. If the treatment is not effective in time, the soil structure can be damaged, soil pores can be blocked, and the soil fertility is seriously reduced; in addition, the method can form a long-term and tired vicious circle for natural water and atmospheric environment, and finally cause destructive results.

At present, due to the heavy crude oil quality and the stricter environmental regulations, the standard discharge of refinery sewage faces more serious challenges. The main method for treating the refinery sewage at the present stage is a chemical flocculation method, and by adding a flocculating agent into the refinery sewage, suspended matters and insoluble or difficultly soluble organic matters in the refinery sewage can be removed. At present, inorganic flocculants such as ferric chloride, polyaluminum ferric chloride and polyaluminum chloride and organic flocculants such as polyacrylamide and chitosan are adopted. However, for the refinery sewage with high oil content and high salt content, a large amount of flocculant needs to be added correspondingly, which not only causes the sedimentation speed of flocs to be slower and leads the treatment efficiency of the refinery sewage to be lower, but also increases the treatment cost of the refinery sewage because of higher cost of the flocculant agent.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the composite flocculant for treating the refining and chemical wastewater, which has a very good treatment effect on the refining and chemical wastewater with high oil content and high salt content, has the characteristics of small dosage and rapid sedimentation, and reduces the treatment cost of the refining and chemical wastewater.

The invention provides a preparation method of the composite flocculant for treating the refining and chemical sewage, which has the characteristics of simple and convenient preparation process.

The invention also provides a treatment method of the refining sewage, and the composite flocculant for treating the refining sewage can realize effective treatment of the refining sewage with high oil content and high salt content.

In order to achieve the aim, the composite flocculant for the treatment of the refining and chemical sewage comprises the following components in parts by weight:

8-15 parts of aluminum salt, 6-10 parts of zinc salt, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent, 70-85 parts of water and strong inorganic acid, wherein the concentration of the strong inorganic acid in the composite flocculant for treating the refined sewage is 0.025-0.085 mol/100 g.

The composite flocculant for treating the refining and chemical sewage (hereinafter referred to as composite flocculant for convenience of explanation) is obtained by compounding organic and inorganic components, wherein the inorganic metal salt is combined with the organic flocculant and is matched with the organic complexing agent, the components have reasonable composition and good mutual synergistic effect, when the high-oil-content and high-salt-content refinery sewage is treated, can form larger and compact floc in the flocculation process, has more three-dimensional net structures, the floc has more complex surface structure and presents very irregular surface structure, thereby leading the floc to have very large surface area and stronger adsorbability, therefore, even under the conditions of high oil content and high salt content with the oil content of 20-150 mg/L and the conductivity of 100-2000 mu s/cm, the method still has good removal effect on turbidity, chroma, COD and the like of the refining sewage; in addition, the floc also has the advantage of rapid sedimentation. Therefore, compared with the traditional flocculating agent, the composite flocculating agent provided by the invention has the advantages of high flocculating efficiency, small dosage, good economic benefit and the like.

The inorganic metal salt used in the present invention is specifically an aluminum salt and a zinc salt, in order to provide aluminum ions and zinc ions, respectively. Among them, the aluminum salt may be specifically a water-soluble salt of aluminum, such as aluminum sulfate, aluminum nitrate, aluminum chloride, or the like; the zinc salt may specifically be a water-soluble salt of zinc, such as zinc sulfate, zinc nitrate, zinc chloride, and the like.

In the present invention, strong inorganic acids are used to provide an acidic environment and to reduce or even avoid the hydrolysis of aluminum and zinc salts. The inorganic strong acid may be one of six inorganic strong acids, i.e., perchloric acid, hydroiodic acid, hydrobromic acid, hydrochloric acid (hydrochloric acid), sulfuric acid, and nitric acid, which are known in the field of inorganic chemistry. The raw material cost and the treatment efficiency of the composite flocculant on the refining sewage are comprehensively considered, and hydrochloric acid, sulfuric acid or nitric acid is generally selected.

It can be understood that the currently available inorganic strong acid reagent hardly achieves 100% purity, for example, the concentration of the commonly used concentrated hydrochloric acid reagent is 36-38%, the concentration of the concentrated sulfuric acid reagent is about 98.3%, and the concentration of the concentrated nitric acid reagent is about 68%, that is, the inorganic strong acid reagent inevitably contains a part of water. In particular, the water carried by the concentrated hydrochloric acid, concentrated sulfuric acid or concentrated nitric acid is also referred to as water in the composite flocculant. For convenience of explanation, the present invention refers to water that is not derived from concentrated hydrochloric acid, concentrated sulfuric acid, or concentrated nitric acid as added water. Therefore, the water component in the composite flocculant for treating the refining sewage comprises water inevitable in the strong inorganic acid and proper amount of externally added water. Of course, if the inorganic strong acid is specifically an aqueous solution of the inorganic acid, for example, diluted hydrochloric acid obtained by diluting concentrated hydrochloric acid with water, the water in the diluted hydrochloric acid is also naturally counted as the water component in the composite flocculant.

Therefore, the raw material can be configured according to the concentration of the inorganic strong acid reagent actually used, and especially, the dosage of the inorganic strong acid reagent and the water is reasonably controlled so that the concentration of the inorganic strong acid in the final composite flocculant reaches 0.025-0.085 mol/100 g. In the specific implementation process of the invention, concentrated hydrochloric acid, concentrated sulfuric acid or concentrated nitric acid is generally diluted by water to obtain the aqueous solution of the corresponding inorganic strong acid, and then the aqueous solution is prepared in proportion to make the final inorganic strong acid reach the concentration requirement.

When the used inorganic strong acid is concentrated hydrochloric acid (the concentration is 36-38%), the composite flocculant specifically comprises the following components in parts by weight based on 100 parts by weight of the total mass: 8-15 parts of aluminum salt, 6-10 parts of zinc salt, 1-3 parts of concentrated hydrochloric acid, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent and the balance of water (namely, external water).

When the used inorganic strong acid is concentrated sulfuric acid (the concentration is about 98.3%), the composite flocculant specifically comprises the following components in parts by weight based on 100 parts by weight of the total mass: 8-15 parts of aluminum salt, 6-10 parts of zinc salt, 3-8 parts of concentrated sulfuric acid, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent and the balance of water (namely, external water).

When the used inorganic strong acid is concentrated nitric acid (the concentration is about 68%), the composite flocculant specifically comprises the following components in parts by weight based on 100 parts by weight of the total mass: 8-15 parts of aluminum salt, 6-10 parts of zinc salt, 2-5 parts of concentrated nitric acid, 0.02-0.05 part of organic flocculant, 3-4 parts of organic complexing agent and the balance of water (namely, external water).

In the invention, the selected organic flocculant can be polyacrylamide, and the organic flocculant can be cationic polyacrylamide, anionic polyacrylamide or nonionic polyacrylamide. In the specific implementation process of the invention, the molecular weight of the polyacrylamide is more than 1000 ten thousand, so that the composite flocculant has better treatment effect.

In the invention, the selected organic complexing agent can specifically select an organic complexing agent which can have certain complexing effect on aluminum ions and zinc ions. In the practice of the present invention, at least one of triethanolamine and thiourea is selected as the organic complexing agent. In the specific implementation process of the invention, triethanolamine is usually selected as the organic complexing agent, taking the raw material cost and the treatment effect of the final composite flocculant into comprehensive consideration.

The aluminum salt such as aluminum sulfate, aluminum nitrate and aluminum chloride, the zinc salt such as zinc sulfate, zinc nitrate and zinc chloride, the inorganic strong acid such as concentrated hydrochloric acid, concentrated nitric acid and concentrated sulfuric acid and the organic complexing agent which are used for preparing the composite flocculant can be analytically pure and can be purchased commercially. The polyacrylamide can be supplied by Clarity excellent materials, Limited liability company, the molecular weight of the polyacrylamide product is more than 1000 ten thousand, and the dissolution time is less than or equal to 90 min.

The invention also provides a preparation method of the composite flocculant for treating the refining sewage, which comprises the following steps:

dissolving 8-15 parts by weight of aluminum salt and 6-10 parts by weight of zinc salt in an aqueous solution of strong inorganic acid to obtain a first solution;

dissolving 0.02-0.05 part by weight of organic flocculant in water, and then mixing with 3-4 parts by weight of complexing agent to obtain a second solution;

mixing the first solution and the second solution, and then aging to obtain a composite flocculant for treating the refined sewage;

wherein the water content in the composite flocculant is 70-85 parts by weight, and the concentration of the inorganic strong acid in the composite flocculant for treating the refining sewage is 0.025-0.085 mol/100 g.

Specifically, the water component may be divided into two parts in advance, one part is used for diluting the strong inorganic acid to obtain an aqueous solution of the strong inorganic acid, and the other part is used for preparing the second solution. That is, first, an inorganic strong acid such as concentrated hydrochloric acid, concentrated nitric acid, or concentrated sulfuric acid is diluted with a part of water to obtain an aqueous solution of the inorganic strong acid, and then, a zinc salt and an aluminum salt are dissolved in the aqueous solution of the inorganic strong acid to obtain a first solution. And dissolving polyacrylamide into the other part of water, adding a complexing agent, and uniformly mixing to obtain a second solution. And finally, mixing the first solution and the second solution and then aging to obtain the composite flocculant.

In the process of preparing the first solution, in order to realize the sufficient dissolution of the zinc salt and the aluminum salt in the aqueous solution of the strong inorganic acid, the temperature of the aqueous solution of the strong inorganic acid can be controlled to be maintained at 55-65 ℃, and the aqueous solution of the strong inorganic acid can be sufficiently stirred in the process of adding the aluminum salt and the zinc salt. After the aluminum salt and the zinc salt are completely dissolved, the obtained first solution is kept stand for a period of time, on one hand, the aluminum salt and the zinc salt are further fully dissolved, on the other hand, the first solution is cooled, and the side reaction caused by the mixing of the first solution and the second solution at a higher temperature is avoided. The first solution can be generally kept still for about 20min at room temperature, so that the temperature of the first solution is reduced to below 30 ℃;

in the process of preparing the second solution, the polyacrylamide is dissolved into the remaining part of the water, and then the complexing agent is added and mixed uniformly. In the process of dissolving polyacrylamide, in order to ensure the full dissolution of polyacrylamide, the temperature of water can be controlled to be maintained at 55-65 ℃, and the mixture is fully stirred. After the second solution is prepared, the second solution may be allowed to stand at room temperature for a period of time to further ensure sufficient dissolution of the polyacrylamide and sufficient mixing with the complexing agent, and to avoid side reactions occurring during the mixing process with the first solution due to the higher temperature of the second solution, and the second solution is usually allowed to stand at room temperature for about 20min to reduce the temperature of the second solution to below 30 ℃.

And finally, slowly pouring the second solution into the first solution, and continuously and rapidly stirring the first solution at the same time to fully mix the first solution and the second solution, preferably to prevent white flocs from being generated, thereby finally obtaining the composite flocculant for the refining sewage treatment.

As mentioned above, the water in the composite flocculant comprises water in concentrated hydrochloric acid, concentrated nitric acid or concentrated sulfuric acid and externally added water. Therefore, the water carried by the inorganic strong acid reagent, the external water for diluting the inorganic strong acid in the process of preparing the first solution and the external water used in the process of preparing the second solution are the sum of the three parts of water, namely the water in the composite flocculant.

In the case of using concentrated hydrochloric acid, concentrated nitric acid, or concentrated sulfuric acid as the inorganic strong acid, the ratio of the added water used for preparing the first solution and the second solution is not particularly limited in the present invention, as long as sufficient dissolution of the zinc salt and the aluminum salt in the aqueous solution of the inorganic strong acid and sufficient dissolution of polyacrylamide in the remaining water can be achieved.

In the specific implementation process of the invention, the mass ratio of the external water for preparing the first solution to the external water for preparing the second solution is 1: 1.5 to 2.5. For example, when concentrated hydrochloric acid is used, 20 to 30 parts of the additional water are added when the first solution is prepared, and 40 to 55 parts of the additional water are added when the second solution is prepared.

After the first solution and the second solution are mixed, the mixture is generally aged at 20 to 30 ℃ to enable the first solution and the compound in the second solution to fully react, for example, the aging is performed at room temperature, and the aging time is controlled to be 2 to 10 hours.

The invention also provides application of the composite flocculant for treating the refining sewage in treating the refining sewage.

As mentioned above, the composite flocculant is prepared by compounding and combining inorganic metal salts such as aluminum salt and zinc salt with an organic flocculant, so that the prepared novel composite flocculant has a three-dimensional net structure and is more stable in floc structure; the organic and inorganic compound use effectively solves the problems of large adding amount, low flocculation efficiency and fine floc of a single inorganic flocculant and the problems of high cost and loose floc of a single organic flocculant. Therefore, the composite flocculant provided by the invention can well realize the treatment of the refinery sewage, is especially suitable for the treatment of the refinery sewage with high oil content (the oil content is 20-150 mg/L), high salt content (the conductivity is 100-2000 mus/cm) and turbidity not more than 100NTU, and has the advantages of small dosage and rapid sedimentation.

The invention also provides a treatment method of the refining sewage, which comprises the following steps: the composite flocculant for treating the refining sewage is added into the refining sewage, the addition amount of the composite flocculant for treating the refining sewage is 0.8-2.4 mg/L, namely 0.8-2.4 mg of the composite flocculant is added into every 1L of the refining sewage to be treated.

The addition amount of the composite flocculant can be reasonably determined according to the actual condition of the refining and chemical sewage, and is generally controlled to be 1.0-2.4 mg/L.

Furthermore, a coagulant aid can be used in the process of adding the composite flocculant, wherein the coagulant aid is some auxiliary agents added for improving or strengthening the coagulation process, the action principle of the coagulant aid is related to specific application, for example, for the condition of excessive propagation of algae, an oxidant can be added for preoxidation to improve the coagulation effect; for low-temperature low-turbidity water treatment, due to high viscosity and poor floc settling property, an organic coagulant aid can be added to increase the floc size, increase the floc density and improve the settling speed; for raw water with low alkalinity, the pH value is reduced in the coagulation process, so that a pH regulator needs to be added for pH adjustment; for wastewater containing iron and manganese, a proper amount of oxidant can be added to destroy organic complexes of iron and manganese. Therefore, the proper coagulant aid can be reasonably selected according to the actual condition of the sewage to be treated, the type of the flocculant and other factors.

In consideration of the actual condition of the refining sewage, the invention adopts the organic coagulant aids such as activated silicic acid, bone glue, PAM and the like to further increase the density of flocs and improve the coagulating sedimentation effect. In the specific implementation process of the invention, the adding amount of the organic coagulant aid is generally 0.4-1.2 mg/L, namely 0.4-1.2 mg of the organic coagulant aid is added into 1L of the refined sewage to be treated on average.

In the specific implementation process of the invention, firstly, a sample of the refined sewage to be treated is taken, and a flocculation test is carried out on the sample by adopting the composite flocculant and the organic coagulant aid, the addition of the composite flocculant and the organic coagulant aid is changed, and a group of formulas with the best flocculation effect is selected, namely the optimal addition.

The composite flocculant for the treatment of the refining sewage is prepared by compounding and combining inorganic metal salts such as aluminum salt and zinc salt with an organic flocculant, so that the prepared novel composite flocculant has a three-dimensional net structure, and is large and compact in floc and more stable in structure. Statistics shows that when the addition amount of the composite flocculant is 0.8-1.2 mg/L, the oil removal rate can reach about 48-65% after about 30min, and the turbidity removal rate can reach 85%, even more than 90%, which shows that the composite flocculant has very good oil removal and turbidity removal effects.

Therefore, the composite flocculant for treating the refining sewage provided by the invention has the advantages of high flocculation efficiency, small dosage, low cost and the like, and particularly has a very good treatment effect on the refining sewage with high oil content (such as 20-150 mg/L of oil content) and high salt content (the conductivity is 100-2000 mu s/cm), so that the problems of low flocculation efficiency and long flocculation time caused by loose flocs of a single flocculant and the cost problem caused by large dosage are effectively solved.

In addition, each component of the composite flocculant for treating the refining sewage provided by the invention can be a conventional reagent at present, so that the raw material cost is further reduced.

The preparation method of the composite flocculant for treating the refining and chemical sewage, provided by the invention, has the characteristic of simple preparation process, and is convenient for practical popularization and application.

According to the method for treating the refining sewage, the composite flocculant for treating the refining sewage is added, so that the refining sewage is effectively treated, and the method has the advantages of high flocculation efficiency, short flocculation time, small addition amount of the composite flocculant and low treatment cost.

Drawings

FIG. 1 shows the floc morphology (x 1000) of an electro-desalted wastewater treated by using the composite flocculant provided in example 1 of the present invention;

FIG. 2 is a floc morphology (x 1000) of an electro-desalted wastewater treated by using the flocculant provided in comparative example 1 of the present invention;

FIG. 3 is a floccule morphology (x 2000) of an electro-desalted wastewater treated by using the composite flocculant provided in example 1 of the present invention;

FIG. 4 is a floc morphology (x 2000) of an electro-desalted wastewater treated with a flocculant provided in comparative example 1 of the present invention;

FIG. 5 shows the floc morphology (x 5000) of the electro-desalted wastewater treated by the composite flocculant provided in example 1 of the present invention;

FIG. 6 shows the floc morphology (x 5000) of an electro-desalted wastewater treated with the flocculant of comparative example 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the following examples and comparative examples, turbidity was measured using a 2100N turbidimeter by HACH corporation; measuring the oil content by adopting an LX-2RI full-automatic infrared oil tester; COD content was measured using DR2700 from HACH, where DRB200 from HACH was used as the digestion apparatus.