A composition, treatment agent, and application for treating oily wastewater and oily sludge.
By using a combination of cyclodextrin, sodium alginate, glycerol, and acrylamide, the high cost of treating acidic oily wastewater and sludge in existing technologies has been solved, achieving efficient and low-cost flocculation and sedimentation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-12-02
- Publication Date
- 2026-05-26
AI Technical Summary
Existing flocculation and coagulation systems require pre-oxidation and pH adjustment to 7-8 when treating acidic oily wastewater and sludge, resulting in high treatment costs and complex processes.
The treatment agent, which uses cyclodextrin, sodium alginate, glycerol and acrylamide as the main components, utilizes hydrogen bonds, covalent bonds and electrostatic forces between functional groups to achieve rapid treatment of sewage and sludge, eliminating the need for pre-oxidation and pH adjustment steps.
It achieves efficient removal of oil and suspended solids under acidic conditions, reducing processing costs and simplifying the process.
Smart Images
Figure CN118125578B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wastewater treatment, specifically relating to a composition, treatment agent, and application for treating oily wastewater and oily sludge. Background Technology
[0002] Currently, the main treatment methods for oily wastewater, polymer-containing wastewater, and oily sludge involve a combination of physical oil removal (hydraulic cyclone, gravity sedimentation, and air flotation), followed by water quality modification (pre-oxidation and pH adjustment) and flocculation sedimentation. In the water quality modification stage, pre-oxidation primarily involves adding hydrogen peroxide to oxidize the water, while pH adjustment involves adding lime or liquid alkali to adjust the pH to 7-8. Then, flocculants such as polyaluminum chloride and polyacrylamide are added to further treat the modified water through flocculation and sedimentation. The treated water is then used for reinjection, recycling, or discharge.
[0003] As oil and gas field extraction processes become more complex, the quality of produced water also becomes more complex. For example, produced water may be strongly acidic (due to carbon dioxide flooding). Treating this produced water requires pre-oxidation and pH adjustment processes to modify it, bringing the pH to a suitable range so that existing flocculants and flocculants such as polyaluminum chloride and polyacrylamide can effectively perform their flocculation and sedimentation functions. Otherwise, if the water's pH deviates from this range, the flocculation and sedimentation effect will be significantly affected.
[0004] In the treatment of acidic oily wastewater and oily sludge, large amounts of lime or liquid alkali are required during pH adjustment. This not only generates a large amount of sludge but also makes the cost per cubic meter of water treatment excessively high. Currently, the cost of lime or liquid alkali accounts for 70% to 75% of the treatment cost. Given the shortcomings of existing flocculation and coagulation systems, which are significantly affected by pH and require complex processes, there is an urgent need to develop new flocculation and coagulation agent systems to simplify the treatment process and achieve cost reduction and efficiency improvement while meeting water quality standards. Summary of the Invention
[0005] The purpose of this invention is to provide a composition for treating oily wastewater and oily sludge, in order to solve the problem that existing flocculation and coagulation systems require pre-oxidation and pH adjustment to 7-8 when treating acidic oily wastewater and sludge, which results in high treatment costs.
[0006] The second objective of this invention is to provide a treatment agent for oily wastewater and oily sludge to solve the above-mentioned problems.
[0007] A third objective of this invention is to provide the application of the above-described composition and reagent in the treatment of acidic oily wastewater and acidic oily sludge.
[0008] To achieve the above objectives, the technical solution adopted by this invention is as follows:
[0009] A composition for treating oily wastewater and oily sludge includes component A and component B, with a mass ratio of component A to component B of (40-100):(5-8); component A is composed of cyclodextrin, sodium alginate, and glycerol in a mass ratio of (2.5-5):(2-8):(0.5-2.0); component B is acrylamide.
[0010] The oily wastewater and oily sludge treatment composition provided by this invention uses cyclodextrin, sodium alginate, glycerol, and acrylamide as main components. It contains functional groups such as polycarboxyl, polyhydroxy, carbonyl, and amino groups, and utilizes hydrogen bonding, covalent bonding, and electrostatic interactions between these functional groups to achieve rapid treatment of wastewater or sludge. Treatment results on acidic oily wastewater and oily sludge show that it has good acid resistance and adsorption capacity, and can remove oil and suspended solids from acidic oily wastewater and sludge without pre-oxidation or pH adjustment, effectively reducing treatment costs and simplifying the treatment process.
[0011] To further optimize the treatment effect on oily wastewater and oily sludge, preferably, the mass ratio of component A to component B is (80-100):(5-8); in component A, the mass ratio of cyclodextrin, sodium alginate, and glycerol is (3.5-5):(4-8):(1.0-2.0).
[0012] An agent for treating oily wastewater and oily sludge is composed of an oily wastewater and oily sludge treatment composition and water. The oily wastewater and oily sludge treatment composition includes component A and component B, with a mass ratio of (40-100):(5-8). Component A is composed of cyclodextrin, sodium alginate, and glycerol in a mass ratio of (2.5-5):(2-8):(0.5-2.0). Component B is acrylamide.
[0013] The oily wastewater and oily sludge treatment agent of the present invention is a water-soluble preparation of the above-mentioned oily wastewater and oily sludge treatment composition. After the above composition is dissolved in water, its stability and dispersibility are further enhanced, which facilitates mixing and treatment with wastewater and sludge and helps to maximize the treatment effect.
[0014] To further optimize the treatment effect on oily wastewater and oily sludge, preferably, the mass ratio of component A to component B is (80-100):(5-8); in component A, the mass ratio of cyclodextrin, sodium alginate, and glycerol is (3.5-5):(4-8):(1.0-2.0).
[0015] Preferably, the mass fraction of the oily wastewater and oily sludge treatment composition in the agent is 9-22%. The content of the active ingredient in the agent is controlled within the above range, the preparation process is simple, and the stability of each component is good.
[0016] To further improve the removal rate of oil and suspended solids, more preferably, the mass fraction of the oily wastewater and oily sludge treatment composition in the reagent is 17-22%.
[0017] A method for preparing an agent for treating oily wastewater and oily sludge includes the following steps:
[0018] (1) Dissolve component A in water to obtain solution A; dissolve component B in water to obtain solution B;
[0019] (2) Mix liquid A and liquid B evenly according to the ratio.
[0020] The preparation method of the oily wastewater and oily sludge treatment agent of the present invention has high configuration efficiency and can conveniently and efficiently obtain treatment agents with good performance consistency.
[0021] Preferably, the solid content of solution A is 10-25%, and the solid content of solution B is 5-8%. Controlling the solid content of solutions A and B within these ranges allows for rapid dissolution of the components and facilitates mixing. When the solid content of solutions A and B is within these ranges, they effectively form flocculent substances with oily pollutants or suspended solids. If the solid content is too low, floc formation will be incomplete, resulting in poor decontamination; if the solid content is too high, lumpy substances will form, also leading to poor decontamination.
[0022] The above-mentioned composition and reagents are used in the treatment of acidic oily wastewater and acidic oily sludge.
[0023] The above-mentioned compositions and agents have good acid and salt resistance and adsorption capacity, making them more effective in the treatment of acidic oily wastewater, polymer-containing wastewater and sludge, which is conducive to significantly reducing agent costs and simplifying treatment processes. Attached Figure Description
[0024] Figure 1 Scanning electron microscope image of sodium alginate dried in a vacuum drying oven at 40°C for 24 hours;
[0025] Figure 2 The image is a scanning electron microscope image of cyclodextrin dried in a vacuum drying oven at 40°C for 24 hours.
[0026] Figure 3 The image shows a scanning electron microscope (SEM) image of pharmaceutical system C after drying in a freeze dryer for 24 hours.
[0027] Figure 4 Scanning electron microscope image of the oily wastewater (pH=5) treated by reagent system C and dried in a freeze dryer for 24 hours;
[0028] Figure 5 This is a water sample image after treating oily wastewater (pH=5) at the site with reagent system C. Detailed Implementation
[0029] During the development of oil and gas fields, a large amount of oily wastewater, polymer-containing wastewater, and oily sludge are often generated. As extraction continues, the difficulty of extraction increases, resulting in a daily increase in the amount of oily wastewater, more complex wastewater composition, and a need for continuous improvement in treatment methods.
[0030] The treatment composition and reagents provided by this invention can replace the pre-oxidation, acid-base adjustment, and flocculation and sedimentation treatment with polyaluminum chloride and polyacrylamide flocculants in existing treatment processes, thereby significantly reducing treatment costs and simplifying the treatment process. The main components of the reagents of this invention are described below:
[0031] Sodium alginate is a natural polysaccharide from brown algae. It is primarily a linear polymer composed of α-L-guluronic acid and β-D-mannuronic acid structural units linked by β-1,4-glycosidic bonds. Sodium alginate is the only naturally occurring hydrophilic polysaccharide anionic polyelectrolyte gel, containing numerous carboxyl and hydroxyl groups in its gel structure, exhibiting excellent biocompatibility and water solubility. Current technologies for utilizing sodium alginate mainly involve modifying it with catalysts, resulting in high overall costs and limiting its further application in practical fields.
[0032] Cyclodextrins are a collective term for a series of cyclic oligosaccharides produced from amylose under the action of cyclodextrin glucosyltransferase produced by bacilli. They contain 6–12 D-glucanyl units and a large number of hydroxyl groups in their structure. Due to their unique hydrophobic interior and hydrophilic exterior properties, cyclodextrins can form inclusion complexes and molecular assemblies with various inorganic, gaseous, and organic molecules through host-guest molecular pairing, van der Waals forces, and hydrophobic interactions. However, further modification techniques based on cyclodextrins also suffer from high costs and are unsuitable for practical field applications.
[0033] The role of glycerol is to generate electrostatic and hydrogen bonding forces with the carboxyl and hydroxyl groups on sodium alginate and β-cyclodextrin through its multiple hydroxyl groups, which is beneficial for floc formation during the decontamination process. Acrylamide can increase the volume of flocs and accelerate the decontamination speed during the decontamination process.
[0034] The implementation process of the present invention will be described in detail below with reference to specific embodiments. In the following embodiments, all pharmaceuticals used are of analytical grade and are commercially available. The cyclodextrin is β-cyclodextrin. The cyclodextrin and sodium alginate are used after vacuum drying to avoid uneven mixing due to moisture absorption by the raw materials.
[0035] I. Specific embodiments of the oily wastewater and oily sludge treatment composition and agent of the present invention are as follows:
[0036] Example 1
[0037] The oily wastewater and oily sludge treatment agent of this embodiment is composed of an oily wastewater and oily sludge treatment composition and water. The oily wastewater and oily sludge treatment composition consists of component A and component B, with a mass ratio of component A to component B of 40:5. Component A is composed of cyclodextrin, sodium alginate, and glycerol in a mass ratio of 2.5:2:0.5. Component B is acrylamide. The mass fraction of the oily wastewater and oily sludge treatment composition in the agent is 9%.
[0038] The oily wastewater and oily sludge treatment composition of this embodiment is the corresponding composition in the reagent of this embodiment.
[0039] The preparation method of the oily wastewater and oily sludge treatment agent in this embodiment includes the following steps:
[0040] (1) Weigh out dried cyclodextrin, dried sodium alginate and glycerol respectively, and mix them evenly in water at 15°C and 200 rpm with a solid content of 10% to obtain pharmaceutical system A.
[0041] (2) Weigh acrylamide and dissolve it in water at a solid content of 5% to obtain reagent system B.
[0042] (3) In water at 15℃, system A and B are mixed at a mass ratio of 4:1 and stirred for 5 minutes to make them evenly mixed, thus preparing the drug system C (i.e. the treatment agent).
[0043] Examples 2-6
[0044] Referring to Example 1, the different treatment agents in Examples 2 to 6 are described below:
[0045] Table 1. Formulations of the treatment agents in Examples 1-6
[0046]
[0047] Table 2. Preparation methods of treatment agents in Examples 1-6
[0048]
[0049]
[0050] II. Application of experimental examples in the treatment of oily wastewater and oily sludge
[0051] Experimental Example 1: SEM Analysis
[0052] Scanning electron microscopy analysis was performed on dried sodium alginate and dried cyclodextrin, and the characterization results are as follows: Figure 1 , Figure 2 As shown.
[0053] Depend on Figure 1 It can be seen that the microstructure of dried sodium alginate exhibits a stacked, blocky structure. From... Figure 2 It can be seen that the microstructure of dried cyclodextrin is a blocky structure with a rough surface.
[0054] The morphology of the drug system C obtained in Example 5 after freeze-drying is as follows: Figure 3 As shown.
[0055] Depend on Figure 3 It can be seen that its microstructure presents a filamentous porous structure with a large specific area, making it easier to flocculate, settle, and adsorb suspended substances or small molecules.
[0056] After treating the oily wastewater (pH=5) with the reagent system C obtained in Example 5, the lower part of the flocculent precipitate was taken and freeze-dried. The specific morphology is as follows: Figure 4 As shown.
[0057] Depend on Figure 4 It can be seen that the microstructure of the reagent changed after treating the wastewater, appearing as fine filamentous material with a certain degree of porosity. This indicates that the reagent system can effectively treat actual oily wastewater without the need for pre-oxidation and pH adjustment processes (i.e., omitting the pre-oxidation and pH adjustment steps), exhibiting good acid and alkali resistance, which is beneficial for on-site application and reducing reagent costs.
[0058] Experiment Example 2: Treatment of Oily Wastewater and Oily Sludge
[0059] The agents described in Examples 1-6 were used to conduct experiments on the treatment of oily wastewater and oily sludge. During the experiments, the agents were added to the oily wastewater and oily sludge, stirred for 30 seconds, and then allowed to stand. The supernatant was then taken to test the oil content and suspended solids content.
[0060] Both the oily wastewater and oily sludge were acidic, with a pH of 5. When treating the oily wastewater, 10 mL of oily wastewater with a pH of 5 was taken, and 20 mg of the reagent was added. When treating the oily sludge, 10 mL of oily sludge with a pH of 5 was taken, and 25 mg of the reagent was added. Specific treatment results are shown in Tables 3 and 4.
[0061] Table 3 shows the treatment results of the agents in each embodiment on oily wastewater.
[0062]
[0063]
[0064] Table 4 shows the treatment results of the agents in each embodiment on oily sludge.
[0065]
[0066] As shown in Tables 3 and 4, the agents in each embodiment achieved oil removal rates of over 77% and suspended solids removal rates of over 92% in oily wastewater. Example 5 demonstrated the best treatment effect, with oil and suspended solids removal rates reaching 98.31% and 99.67%, respectively. For oily sludge, the removal rates reached over 79% and suspended solids removal rates of over 93%. Example 5 again showed the best treatment effect, with oil and suspended solids removal rates reaching 97.46% and 99.82%, respectively.
[0067] Examples of oily wastewater (pH=5) before and after treatment in Example 5 are shown below. Figure 5 As shown in the figure, the wastewater changed from turbid to clear after treatment, demonstrating good application results. In summary, compared with existing treatment processes involving pre-oxidation, pH adjustment, and flocculation, this invention eliminates the pre-oxidation and pH adjustment processes, significantly reducing the cost of chemicals for oilfield wastewater treatment; furthermore, the water quality treated using this method meets the required standards.
Claims
1. The application of the reagent in the treatment of acidic oily wastewater and acidic oily sludge, characterized in that, A reagent is added to oily wastewater and oily sludge to remove suspended solids. The reagent is composed of an oily wastewater and oily sludge treatment composition and water. The oily wastewater and oily sludge treatment composition includes component A and component B, with a mass ratio of (40~100):(5~8). Component A is composed of cyclodextrin, sodium alginate, and glycerol in a mass ratio of (2.5~5):(2~8):(0.5~2.0). Component B is acrylamide. Component A is dissolved in water to obtain solution A. Component B is dissolved in water to obtain solution B. Solutions A and B are mixed evenly according to the specified ratio to obtain the reagent.
2. The application as described in claim 1, characterized in that, The mass ratio of component A to component B is (80~100): (5~8); in component A, the mass ratio of cyclodextrin, sodium alginate, and glycerol is (3.5~5): (4~8): (1.0~2.0).
3. The application as described in claim 1, characterized in that, The mass fraction of the oily wastewater and oily sludge treatment composition in the reagent is 9-22%.
4. The application as described in claim 3, characterized in that, The mass fraction of the oily wastewater and oily sludge treatment composition in the reagent is 17-22%.
5. A treatment agent for acidic oily wastewater and acidic oily sludge, characterized in that, The treatment agent is composed of an oily wastewater and oily sludge treatment composition and water. The oily wastewater and oily sludge treatment composition includes component A and component B, with a mass ratio of (40~100):(5~8). Component A is composed of cyclodextrin, sodium alginate, and glycerol in a mass ratio of (2.5~5):(2~8):(0.5~2.0). Component B is acrylamide. Component A is dissolved in water to obtain solution A. Component B is dissolved in water to obtain solution B. Solution A and solution B are mixed evenly according to the specified ratio to obtain the agent.
6. The treatment agent for acidic oily wastewater and acidic oily sludge as described in claim 5, characterized in that, The mass ratio of component A to component B is (80~100): (5~8); in component A, the mass ratio of cyclodextrin, sodium alginate, and glycerol is (3.5~5): (4~8): (1.0~2.0).
7. The treatment agent for acidic oily wastewater and acidic oily sludge as described in claim 5 or 6, characterized in that, The mass fraction of the oily wastewater and oily sludge treatment composition in the reagent is 9-22%.
8. The treatment agent for acidic oily wastewater and acidic oily sludge as described in claim 7, characterized in that, The mass fraction of the oily wastewater and oily sludge treatment composition in the reagent is 17-22%.
9. A composition for treating acidic oily wastewater and acidic oily sludge, characterized in that, The product comprises component A and component B, with a mass ratio of (40~100): (5~8). Component A consists of cyclodextrin, sodium alginate, and glycerol in a mass ratio of (2.5~5): (2~8): (0.5~2.0). Component B is acrylamide. In use, component A is dissolved in water to obtain solution A, and component B is dissolved in water to obtain solution B. Solution A and solution B are mixed evenly according to the ratio to obtain a treatment agent for acidic oily wastewater and acidic oily sludge.
10. The composition for treating acidic oily wastewater and acidic oily sludge as described in claim 9, characterized in that, The mass ratio of component A to component B is (80~100): (5~8); in component A, the mass ratio of cyclodextrin, sodium alginate, and glycerol is (3.5~5): (4~8): (1.0~2.0).