High-suspended-matter sewage treatment agent for oil extraction plant

Abstract

The invention relates to the technical field of sewage treatment, and particularly discloses a high-suspended-matter sewage treatment agent for an oil extraction plant. The invention discloses a high-suspended-matter sewage treatment agent for an oil extraction plant. The high-suspended-matter sewage treatment agent comprises 40-60 parts of modified bentonite; 5-15 parts of ferrous sulfate; 5-15 parts of aluminum ferric sulfate; 1 to 5 parts of ethylenediamine tetraacetic acid; 10 to 20 parts of an active biochar material; 3 to 8 parts of chitosan; 5 to 10 parts of a flocculating agent; the modified bentonite is obtained by modifying bentonite through laccase and nano zero-valent iron; the active biochar material is obtained by taking waste biomass as a raw material and carrying out semi-carbonization and activation treatment. The sewage treatment agent disclosed by the invention can be used for purifying high-suspended-matter sewage generated by oil extraction plants and oil wells, has high removal efficiency on suspended matters, and can effectively remove organic humus, so that the content of the suspended matters in the treated sewage reaches the standard.

Description

Technical Field

[0001] The present application relates to the technical field of sewage treatment, and more specifically, to a sewage treatment agent for high-suspended solid sewage in oil production plants. Background Art

[0002] The sewage generated by oil production plants is characterized by complex composition, high suspended solid content, high oil content, and the presence of various chemical substances. Among them, suspended solids are a key pollutant index, and these suspended solids include cuttings, clay particles, bacterial cells, corrosion products, and various organic and inorganic impurities. They will cause an increase in the turbidity of the sewage, affect the effect of subsequent treatment processes, and even cause wear and blockage of equipment. For the high-suspended solid sewage generated by oil production plants, relying solely on natural sedimentation, the sedimentation speed is slow, it is difficult to achieve efficient solid-liquid separation, and it cannot meet the requirements of large-scale sewage treatment. At present, the high-suspended solid sewage generated by oil production plants is mainly purified by adding treatment agents.

[0003] In related technologies, for example, the patent document with the publication number CN109574118B discloses a sewage treatment composite agent and its preparation method. The technical solution adopted is: a sewage treatment composite agent, calculated by mass percentage, includes 85% - 94% of bentonite, 0.5% - 2.5% of sodium tartrate, 0.5% - 2.5% of carboxyethylthiosuccinic acid, 0.4% - 1.6% of chitosan, and 4% - 9% of hard metal salts; the bentonite is inorganic modified bentonite.

[0004] However, when this composite agent is actually applied to the treatment of high-suspended solid sewage in oil production plants, there are still some deficiencies. The components of suspended solids in the sewage of oil production plants are complex, including not only inorganic solid impurities but also humus rich in residues of animals and plants in the formation that have been transformed through long-term natural decomposition. These humus substances have complex structures and high molecular weights, and are mainly composed of various components such as humic acid, fulvic acid, and humin. They exist in the sewage in the form of colloids or dissolved states. Although components such as bentonite in the above composite agent show certain adsorption and flocculation abilities for solid impurities, they cannot effectively remove humus. If humus is not removed from the sewage through effective means, it will continue to decompose after being discharged into the natural environment. This process will consume a large amount of dissolved oxygen in the water body, thereby inducing the problem of water body hypoxia and causing potential negative impacts on the aquatic ecosystem. Therefore, there are still certain defects in the current composite agent in efficiently removing humus from the sewage of oil production plants, and further research and improvement are needed. Summary of the Invention

[0005] Based on the above situation, in order to improve the removal effect of the treatment agent on humus in sewage and ensure that the suspended solid content of the treated sewage meets the standard, the present application provides a sewage treatment agent for high-suspended solid sewage in oil production plants.

[0006] The sewage treatment agent for high suspended solids in oil production plants provided by this application adopts the following technical solution: A sewage treatment agent for high suspended solids in oil production plants is made from the following raw materials in parts by weight: 40 - 60 parts of modified bentonite; 5 - 15 parts of ferrous sulfate; 5 - 15 parts of ferric aluminum sulfate; 1 - 5 parts of ethylenediaminetetraacetic acid; 10 - 20 parts of activated biochar material; 3 - 8 parts of chitosan; 5 - 10 parts of flocculant; The modified bentonite is obtained by modifying bentonite with laccase and nano zero-valent iron; The activated biochar material is obtained by using waste biomass as raw material and undergoing semi-carbonization and activation treatment.

[0007] Its effect is as follows: The modified bentonite is obtained by modifying bentonite with laccase and nano zero-valent iron. Laccase is a copper-containing polyphenol oxidase with significant degradation ability for humus. The humus structure in the sewage of oil production plants is complex. Laccase can catalyze the oxidation reaction of compounds such as phenols and aromatic amines in humus and decompose them into small molecule substances. By degrading humus, and then adsorbing and purifying the degraded humus through modified bentonite, the content of suspended solids in the sewage of oil production plants is effectively reduced. The surface of nano zero-valent iron is rich in active sites, which can interact with laccase molecules through chemical bonding and electrostatic adsorption, so as to firmly fix laccase on its surface. At the same time, when nano zero-valent iron is mixed with bentonite, it can form a bridging effect between bentonite particles, making laccase more stably loaded on bentonite, thus improving the stability of modification. Nano zero-valent iron has strong reducing ability. For some complex structures in humus, it can destroy some of its structures through reduction, reducing the molecular weight and complexity of humus, which is more conducive to the further degradation of humus by laccase. In addition, the degraded humus products carry a certain charge, and the surface charge of nano zero-valent iron can interact with these products through electrostatic attraction, thereby enhancing the adsorption ability of modified bentonite to the degradation products.

[0008] Ferrous sulfate and ferric aluminum sulfate hydrolyze in sewage to form iron hydroxide and aluminum hydroxide colloids. These colloids have strong adsorption and flocculation effects, enabling the suspended solids in the sewage to aggregate into larger particles, thus facilitating precipitation and removal. Ethylenediaminetetraacetic acid (EDTA) can form stable complexes with metal ions in the sewage, reducing the interference of metal ions on other components and also helping to remove some heavy metal ions. Chitosan has good flocculation and adsorption properties and can combine with suspended solids and colloidal substances in the sewage to form flocs, accelerating the precipitation process. The flocculant further enhances the flocculation effect of suspended solids in the sewage, increases the precipitation speed, and ensures that the content of suspended solids in the treated sewage meets the standard. The treatment agent of this application has an efficient removal effect on humus in the sewage of oil refineries, and also has good adsorption and flocculation effects on other suspended solids, significantly reducing the content of suspended solids and turbidity in the sewage.

[0009] Optionally, the modified bentonite is prepared by the following method: A. Prepare an aqueous solution of laccase and an ethanol dispersion of nano-zero-valent iron; add bentonite to deionized water, stir for 10 - 20 min, and then perform ultrasonic treatment for 15 - 30 min to obtain a bentonite suspension; B. Place the bentonite suspension in a reaction kettle filled with nitrogen. Under the stirring condition of 100 - 200 r / min, add the ethanol dispersion of nano-zero-valent iron, then stir and react for 1 - 2 h. Then add the aqueous solution of laccase into the reaction kettle, maintain the reaction temperature at 30 - 40 °C, and react for 2 - 4 h to obtain an intermediate solution; C. Transfer the intermediate solution to a centrifuge tube, centrifuge at a speed of 3000 - 5000 r / min for 10 - 15 min under nitrogen protection, separate out the solid precipitate, then wash the solid precipitate and dry it under a nitrogen atmosphere to obtain the modified bentonite.

[0010] By adopting the above technical solution, under nitrogen protection, nano-zero-valent iron is first mixed with bentonite, and its active sites bind to the surface of bentonite. Subsequently, laccase is added. Nano-zero-valent iron immobilizes laccase through chemical bonding and electrostatic adsorption. At the same time, its bridging effect between bentonite particles makes laccase more stably loaded on bentonite, ensuring that laccase can effectively contact and decompose humus. Nano-zero-valent iron can also reduce humus, creating more favorable conditions for the action of laccase. The modified bentonite prepared by the above method not only has good adsorption and flocculation effects on other suspended solids, but also has good removal effects on humus in the sewage, thus helping to reduce the content of suspended solids in the sewage of oil refineries.

[0011] Optionally, the concentration of the laccase aqueous solution described in step A is 10 - 50 mg / mL; the concentration of the ethanol dispersion of nano zero-valent iron is 5 - 20 mg / mL; the mass concentration of the bentonite suspension is 5% - 10%.

[0012] By adopting the above technical solution, the laccase aqueous solution with the above concentration ensures that laccase can fully participate in the decomposition reaction of humus; when the concentration of the ethanol dispersion of nano zero-valent iron is within the above-provided concentration range, its active sites can fully interact with laccase and bentonite; the bentonite suspension with a specific mass concentration makes the bentonite particles disperse evenly, providing sufficient contact sites for nano zero-valent iron and laccase, and thus enabling the modified bentonite to maintain a good modification effect.

[0013] Optionally, the mass ratio of the bentonite suspension, the ethanol dispersion of nano zero-valent iron, and the laccase aqueous solution in step B is 10 : (0.5 - 1) : (1 - 2).

[0014] Optionally, the active biochar material is prepared by the following method: The waste biomass is heated at 180 - 190 °C and an oxygen volume concentration of 1% - 5% for 2 - 3 h to obtain semi-carbonized biomass, and then the semi-carbonized biomass is soaked in a potassium hydroxide solution for 12 - 24 h. After soaking, the semi-carbonized biomass is dried, and then calcined at 450 - 600 °C for 1 - 2 h under anaerobic conditions to obtain the active biochar material.

[0015] By adopting the above technical solution, the active biochar material prepared by the above method has a rich pore structure and surface activity, can efficiently adsorb humus and other pollutants in sewage, and improves the removal ability of sewage treatment agents for complex pollutants. After the waste biomass is semi-carbonized and activated by potassium hydroxide under specific conditions, potassium carbonate generated by the reaction of potassium hydroxide and carbon volatilizes during the calcination process, leaving rich pores and increasing the specific surface area. At the same time, after the active biochar material is mixed with components such as modified bentonite, the presence of the active biochar material can provide a stable microenvironment for active components such as laccase and promote the decomposition of humus by laccase.

[0016] Optionally, the mass concentration of the potassium hydroxide solution is 30% - 40%, and the mass ratio of the semi-carbonized biomass to the potassium hydroxide solution is 1 : (3 - 4).

[0017] Optionally, the waste biomass is any one of rice husk, corn straw, and sugarcane bagasse.

[0018] Optionally, the flocculant is any one of polyferric chloride or polyacrylamide.

[0019] Optionally, the viscosity of the chitosan is 0.7 - 1 Pa·s.

[0020] By adopting the above technical solution, chitosan within this viscosity range has appropriate fluidity and molecular extensibility in solution, and the amino and hydroxyl groups on its molecular chain can better interact with pollutants. During the flocculation process, it can cooperate with the flocculant to improve the removal effect of suspended solids and humus in sewage.

[0021] This application also provides a preparation method for the sewage treatment agent for high-suspended solids in oil production plants, adopting the following technical solution: A preparation method for the sewage treatment agent for high-suspended solids in oil production plants includes the following steps: S1. Mix the modified bentonite and the activated biochar material, and stir at a speed of 100 - 150 r / min for 5 - 10 min to obtain a premix; S2. Mix ferrous sulfate, ferric aluminum sulfate, ethylenediaminetetraacetic acid, chitosan, and the flocculant with the premix and continue stirring for 20 - 30 min to obtain a mixture; S3. Transfer the mixture to an extrusion granulator for extrusion granulation to obtain granular agents, and dry the granular agents at 60 - 80 °C for 3 - 5 h to obtain the sewage treatment agent for high-suspended solids in oil production plants.

[0022] By adopting the above technical solution, multiple components in the above method cooperate. Ferrous sulfate, ferric aluminum sulfate, etc. cooperate with the modified bentonite and the activated biochar to enhance the treatment capabilities such as flocculation and adsorption of impurities in sewage. The modified bentonite is modified by laccase and nano-zero valent iron, which can efficiently degrade and adsorb humus in sewage, effectively reduce the suspended solid content, and improve the sewage purification effect. In summary, this application has the following beneficial effects: 1. This application uses laccase and nano-zero valent iron to modify bentonite. Since laccase can catalyze the oxidation reaction of phenolic, aromatic amine and other compounds in humus to decompose them into small molecules, and nano-zero valent iron can enhance the immobilization of laccase and reduce the complex structure of humus, the synergistic effect of the two enhances the effect of the modified bentonite on the efficient degradation and adsorption of humus in the sewage of oil production plants, and can effectively reduce the suspended solid content in sewage.

[0023] 2. This application preferably adopts steps such as semi-carbonizing waste biomass under specific conditions, soaking it with a specific concentration of potassium hydroxide solution, and high-temperature roasting to prepare the activated biochar material. Since this process forms a rich pore structure and a large specific surface area, and can provide a stable microenvironment for active components such as laccase, the activated biochar material can efficiently adsorb small molecules and other pollutants after the degradation of humus in sewage, and cooperate with the modified bentonite to improve the effect of the sewage treatment agent on the removal ability of complex pollutants.

[0024] 3. The method of the present application is to mix modified bentonite, activated biochar materials with ferrous sulfate, aluminum ferric sulfate, ethylenediaminetetraacetic acid, chitosan and flocculants in a specific proportion, and adopt a suitable preparation process. Each component plays its own adsorption, flocculation, complexation and other effects, and cooperates with each other. The prepared treatment agent has a good removal effect on humus and other suspended matter in oil field wastewater, can significantly reduce the suspended matter content and turbidity in wastewater, and ensure that the wastewater is discharged in compliance with the standards. DETAILED DESCRIPTION

[0025] The present application is further described in detail below with reference to the embodiments.

[0026] Preparation example of modified bentonite Preparation Example 1 The modified bentonite is prepared by the following method: A. Prepare a 10 mg / mL laccase aqueous solution and a 5 mg / mL nano zero-valent iron ethanol dispersion; add 5 kg of bentonite to 95 kg of deionized water, stir for 10 min, and then ultrasonicate for 15 min to obtain a bentonite suspension with a mass concentration of 5%; B. 10 kg of bentonite suspension was placed in a reactor filled with nitrogen. Under stirring conditions of 100 r / min, 0.5 kg of nano zero-valent iron ethanol dispersion was added, and then stirred for reaction for 1 hour. Then, 1 kg of laccase aqueous solution was added to the reactor. The reaction temperature was maintained at 30° C. and the reaction was carried out for 2 hours to obtain an intermediate solution. C. The intermediate solution was transferred to a centrifuge tube, and centrifuged at 3000 r / min for 10 min under nitrogen protection to separate the solid precipitate, and then the solid precipitate was washed and dried under nitrogen atmosphere to obtain modified bentonite.

[0027] Preparation Example 2 The modified bentonite is prepared by the following method: A. Prepare a laccase aqueous solution with a concentration of 30 mg / mL and an ethanol dispersion of nano zero-valent iron with a concentration of 12 mg / mL; add 8 kg of bentonite to 92 kg of deionized water, stir for 15 min, and then ultrasonicate for 25 min to obtain a bentonite suspension with a mass concentration of 8%; B. 10 kg of bentonite suspension was placed in a reactor filled with nitrogen. Under stirring conditions of 150 r / min, 0.8 kg of nano zero-valent iron ethanol dispersion was added, and then stirred for reaction for 1.5 h. Then, 1.5 kg of laccase aqueous solution was added to the reactor. The reaction temperature was maintained at 35° C. and the reaction was carried out for 3 h to obtain an intermediate solution. C. Transfer the intermediate solution into a centrifuge tube, centrifuge at a speed of 4000 r / min for 12 min under nitrogen protection to separate out the solid precipitate, then wash the solid precipitate and dry it under a nitrogen atmosphere to obtain the modified bentonite.

[0028] Preparation Example 3 The modified bentonite is prepared by the following method: A. Prepare an aqueous laccase solution with a concentration of 50 mg / mL and an ethanol dispersion of nano zero-valent iron with a concentration of 20 mg / mL; add 10 kg of bentonite to 90 kg of deionized water, stir for 20 min, and then perform ultrasonic treatment for 30 min to obtain a bentonite suspension with a mass concentration of 10%. B. Place 10 kg of the bentonite suspension in a reaction kettle filled with nitrogen. Under the stirring condition of 200 r / min, add 1 kg of the ethanol dispersion of nano zero-valent iron, then stir and react for 2 h. Then add 2 kg of the aqueous laccase solution into the reaction kettle, maintain the reaction temperature at 40 °C, and react for 4 h to obtain an intermediate solution. C. Transfer the intermediate solution into a centrifuge tube, centrifuge at a speed of 5000 r / min for 15 min under nitrogen protection to separate out the solid precipitate, then wash the solid precipitate and dry it under a nitrogen atmosphere to obtain the modified bentonite.

[0029] Preparation Example 4 The modified bentonite is different from that in Preparation Example 3 in that in this preparation example, in step B, the mass ratio of the bentonite suspension, the ethanol dispersion of nano zero-valent iron, and the aqueous laccase solution is 10:3:3.

[0030] Preparation Example 5 The modified bentonite is different from that in Preparation Example 3 in that in this preparation example, in step A, an aqueous urease solution with a concentration of 50 mg / mL is prepared, and in step B, an equal amount of the aqueous urease solution is used instead of the aqueous laccase solution to participate in the reaction.

[0031] Preparation Example 6 The modified bentonite is different from that in Preparation Example 3 in that in this preparation example, the ethanol dispersion of nano zero-valent iron is added in step B. Specifically, step B is as follows: Place 10 kg of the bentonite suspension in a reaction kettle filled with nitrogen, then add 2 kg of the aqueous laccase solution into the reaction kettle, maintain the reaction temperature at 40 °C, and react for 4 h to obtain an intermediate solution.

[0032] Preparation Examples of Active Biochar Materials Preparation Example 7 The active biochar material is prepared by the following method: Rice husks are heated at 180 °C with an oxygen concentration of 1% for 2 h to obtain semi-carbonized biomass. Then, the semi-carbonized biomass is soaked in a 30% potassium hydroxide solution by mass for 12 h, with the mass ratio of the semi-carbonized biomass to the potassium hydroxide solution being 1:3. After soaking, the semi-carbonized biomass is dried, and then calcined at 450 °C for 1 h under anaerobic conditions to obtain an activated biochar material.

[0033] Preparation Example 8 An activated biochar material is prepared by the following method: Corn straw is heated at 185 °C with an oxygen concentration of 3% for 2.5 h to obtain semi-carbonized biomass. Then, the semi-carbonized biomass is soaked in a 35% potassium hydroxide solution by mass for 18 h, with the mass ratio of the semi-carbonized biomass to the potassium hydroxide solution being 1:3.5. After soaking, the semi-carbonized biomass is dried, and then calcined at 550 °C for 1.5 h under anaerobic conditions to obtain an activated biochar material.

[0034] Preparation Example 9 An activated biochar material is prepared by the following method: Corn straw is heated at 190 °C with an oxygen concentration of 5% for 3 h to obtain semi-carbonized biomass. Then, the semi-carbonized biomass is soaked in a 40% potassium hydroxide solution by mass for 24 h, with the mass ratio of the semi-carbonized biomass to the potassium hydroxide solution being 1:4. After soaking, the semi-carbonized biomass is dried, and then calcined at 600 °C for 2 h under anaerobic conditions to obtain an activated biochar material.

[0035] Preparation Example 10 The activated biochar material is different from that in Preparation Example 9 in that in this preparation example, an equal amount of a 40% sodium hydroxide solution by mass is used to soak the semi-carbonized biomass.

[0036] Examples Example 1 A sewage treatment agent for high-suspended solids in oil refineries, and its raw material components and dosages are shown in Table 1. Among them, the modified bentonite is the modified bentonite prepared in Preparation Example 1; the activated biochar material is the modified biochar material prepared in Preparation Example 7; the viscosity of chitosan is 0.7 Pa·s; and the flocculant is polyferric chloride.

[0037] A method for a sewage treatment agent for high-suspended solids in oil refineries includes the following steps: S1. Mix the modified bentonite and the activated biochar material, and stir at a speed of 100 r / min for 10 min to obtain a premix; S2. Mix ferrous sulfate, ferric aluminum sulfate, ethylenediaminetetraacetic acid, chitosan and a flocculant with the premix and continue stirring for 20 min to obtain a mixed material. S3. Transfer the mixed material to an extrusion granulator for extrusion granulation to obtain granular medicaments, and dry the granular medicaments at 60 °C for 5 h to obtain the medicament for treating high-suspended solid sewage in an oil production plant.

[0038] Example 2 A medicament for treating high-suspended solid sewage in an oil production plant, and the raw material components and dosages are shown in Table 1. Among them, the modified bentonite is the modified bentonite prepared in Preparation Example 2; the activated biochar material is the modified biochar material prepared in Preparation Example 8; the viscosity of chitosan is 0.8 Pa·s; the flocculant is polyacrylamide.

[0039] A method for preparing a medicament for treating high-suspended solid sewage in an oil production plant, comprising the following steps: S1. Mix the modified bentonite and the activated biochar material, and stir at a speed of 120 r / min for 8 min to obtain a premix. S2. Mix ferrous sulfate, ferric aluminum sulfate, ethylenediaminetetraacetic acid, chitosan and a flocculant with the premix and continue stirring for 25 min to obtain a mixed material. S3. Transfer the mixed material to an extrusion granulator for extrusion granulation to obtain granular medicaments, and dry the granular medicaments at 70 °C for 4 h to obtain the medicament for treating high-suspended solid sewage in an oil production plant.

[0040] Example 3 A medicament for treating high-suspended solid sewage in an oil production plant, and the raw material components and dosages are shown in Table 1. Among them, the modified bentonite is the modified bentonite prepared in Preparation Example 3; the activated biochar material is the modified biochar material prepared in Preparation Example 9; the viscosity of chitosan is 1.0 Pa·s; the flocculant is polyacrylamide.

[0041] A method for preparing a medicament for treating high-suspended solid sewage in an oil production plant, comprising the following steps: S1. Mix the modified bentonite and the activated biochar material, and stir at a speed of 150 r / min for 5 min to obtain a premix. S2. Mix ferrous sulfate, ferric aluminum sulfate, ethylenediaminetetraacetic acid, chitosan and a flocculant with the premix and continue stirring for 30 min to obtain a mixed material. S3. Transfer the mixed material to an extrusion granulator for extrusion granulation to obtain granular medicaments, and dry the granular medicaments at 80 °C for 3 h to obtain the medicament for treating high-suspended solid sewage in an oil production plant.

[0042] Table 1 Raw material components and dosages (kg) of the treatment medicaments in Examples 1-3

[0043] Example 4 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that the modified bentonite in this example is the modified bentonite prepared in Preparation Example 4.

[0044] Example 5 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that the activated biochar material in this example is the modified biochar material prepared in Preparation Example 10.

[0045] Example 6 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that the flocculant in this example is aluminum sulfate.

[0046] Comparative Example Comparative Example 1 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that an equal amount of unmodified bentonite is used in this comparative example to replace the modified bentonite.

[0047] Comparative Example 2 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that an equal amount of coal-based activated carbon is used in this comparative example to replace the biochar material.

[0048] Comparative Example 3 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that the modified bentonite in this comparative example is the modified bentonite prepared in Preparation Example 5.

[0049] Comparative Example 4 A sewage treatment agent for high suspended solids in oil production plants, which is different from Example 1 in that the modified bentonite in this comparative example is the modified bentonite prepared in Preparation Example 6.

[0050] Performance Detection Test In this example, the equipment flushing sewage generated in the drilling platform area during the drilling process is used as the sewage sample to be tested. After testing, its suspended solid content is shown in Table 2.

[0051] Table 2 Sewage Suspended Solid Content

[0052] Detection Method 1. Sample collection: After mixing the above-mentioned sewage samples to be tested evenly, they are divided into several equal parts, each part of the water sample has a volume of 500 mL, sealed and labeled.

[0053] 2. Reagent addition and reaction: Take 10 portions of 500 mL of sewage water samples respectively, and sequentially add the reagents prepared in Examples 1-6 and Comparative Examples 1-4. The addition amount of the reagent is 25 g. Place the water samples on a magnetic stirrer and stir and react at a rotation speed of 200 r / min for 30 min to fully mix and react the reagent with the sewage.

[0054] 3. After the reaction is completed, centrifuge the water samples again in a centrifuge at a rotation speed of 4000 r / min for 15 min, and take the supernatant. Measure the turbidity of the treated water samples with a turbidimeter; measure the absorbance of humus in the treated water samples with a spectrophotometer, and calculate the humus content according to the standard curve; filter the supernatant with a 0.45 μm filter membrane, and measure the suspended solid content of the treated water samples by the gravimetric method. The results are shown in Table 3.

[0055] Table 3 Detection results

[0056] The suspended solid removal rates of the sewage in Examples 1-3 are all above 98%, and among them, Example 1 is the highest, reaching 99.08%. This shows that the reagent prepared by compounding modified bentonite, activated biochar materials and other components in a specific proportion has a significant effect on removing suspended solids in the sewage for flushing drilling platform equipment. Laccase and nano-zero-valent iron in the modified bentonite synergistically degrade and adsorb humus, the rich pore structure of the activated biochar material adsorbs small molecule pollutants, and the flocculation of the colloids generated by the hydrolysis of ferrous sulfate, ferric aluminum sulfate, etc. and the flocculant together promote the coagulation and sedimentation of suspended solids. The contents of inorganic solid particles in the sewage treated in Examples 1-3 are 8 mg / L, 10 mg / L, and 13 mg / L respectively. The modified bentonite and the activated biochar material have a certain adsorption effect on inorganic solid particles, and at the same time the flocculant makes the inorganic particles coagulate and sediment, and multiple components synergistically reduce the content of inorganic solid particles. The contents of organic humus in the sewage treated in Examples 1-3 are reduced to relatively low levels, which are 3 mg / L, 5 mg / L, and 4 mg / L respectively. This benefits from the oxidation and decomposition of phenolic and aromatic amine compounds in humus by laccase, the enhancement of laccase activity by nano-zero-valent iron and the reduction of the complex structure of humus, making it more easily decomposed and adsorbed, and the further adsorption of small molecules after the degradation of humus by the activated biochar material, thus effectively reducing the content of organic humus in the sewage.

[0057] In Example 4, the suspended solid removal rate of the sewage decreased to 96.58%, which was lower than that in Examples 1-3. This might be because the mass ratio of the bentonite suspension, the ethanol dispersion of nano zero-valent iron, and the laccase aqueous solution in Preparation Example 4 was changed, affecting the synergistic effect of laccase and nano zero-valent iron in the modified bentonite, resulting in a decrease in the degradation and adsorption ability of humus, and further affecting the overall suspended solid removal effect. After treatment, the content of organic humus increased to 25 mg / L, indicating that this change in mass ratio was not conducive to the decomposition and adsorption of humus, making the humus removal effect worse.

[0058] The content of organic humus in the sewage after treatment in Example 5 was 29 mg / L, indicating that the adsorption ability of the treatment agent prepared in this example for the degradation products of humus was weakened. Since sodium hydroxide solution was used instead of potassium hydroxide solution in Preparation Example 10 to prepare the activated biochar material, the pore structure and surface properties of the activated biochar material were changed, resulting in a decrease in its adsorption ability, thus affecting the removal effect of suspended solids and humus. The suspended solid removal rate of the sewage after treatment in Example 6 was 96.16%. It shows that when aluminum sulfate was selected instead of polyaluminum chloride as the flocculant, the flocculation effect of aluminum sulfate was slightly inferior, resulting in a decrease in the overall suspended solid removal rate.

[0059] The suspended solid removal rates of the sewage after treatment in Comparative Examples 1-4 were basically 94.41 or below. Compared with Examples 1-3, the suspended solid removal rate of the sewage decreased significantly. It can be seen that the main reason was that the content of organic humus in the sewage after treatment in Comparative Examples 1-4 was still relatively high, indicating that the treatment agents prepared in Comparative Examples 1-4 could not effectively remove organic humus, thus resulting in a decrease in the suspended solid removal rate.

[0060] The suspended solid removal rate of Comparative Example 1 was 93.82%, which was significantly lower than that in the example. Using unmodified bentonite, lacking the degradation and adsorption effects of laccase and nano zero-valent iron on humus, and relying only on the adsorption performance of bentonite itself, it was unable to effectively remove humus in the sewage, thus affecting the overall suspended solid removal effect.

[0061] The suspended solid removal rate of Comparative Example 2 was 93.49%. Substituting coal-based activated carbon for the biochar material, the pore structure and surface functional groups of coal-based activated carbon were different from those of the activated biochar material, and its adsorption ability for the degradation products of humus and other pollutants was weak, affecting the removal of suspended solids.

[0062] The suspended solid removal rate of Comparative Example 3 was 94.16%. In Preparation Example 5, urease was used instead of laccase. Urease could not effectively catalyze the oxidation reaction of phenolic and aromatic amine compounds in humus like laccase, and was unable to degrade humus, thus reducing the suspended solid removal effect.

[0063] The suspended solid removal rate of Comparative Example 4 was 94.41%. In Preparation Example 6, nano zero-valent iron was not added, resulting in a decrease in the stability and activity of laccase, thus weakening the ability to degrade humus, which in turn affected the removal of suspended solids.

[0064] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment that do not contribute creatively as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A chemical agent for treating high-suspended solid sewage in an oil production plant, characterized in that, It is made from the following raw materials in parts by weight: 40 - 60 parts of modified bentonite; 5 - 15 parts of ferrous sulfate; 5 - 15 parts of ferric aluminum sulfate; 1 - 5 parts of ethylenediaminetetraacetic acid; 10 - 20 parts of activated biochar material; 3 - 8 parts of chitosan; 5 - 10 parts of flocculant; The modified bentonite is obtained by modifying bentonite with laccase and nano zero - valent iron; The activated biochar material is obtained by using waste biomass as raw material and through semi - carbonization and activation treatment.

2. The sewage treatment agent for high suspended solids in an oil production plant according to claim 1, characterized in that The modified bentonite is prepared by the following method: A. Prepare an aqueous solution of laccase and an ethanol dispersion of nano zero - valent iron; add bentonite to deionized water, stir for 10 - 20 min, and then perform ultrasonic treatment for 15 - 30 min to obtain a bentonite suspension; B. Place the bentonite suspension in a reaction kettle filled with nitrogen. Under the stirring condition of 100 - 200 r / min, add the ethanol dispersion of nano zero - valent iron, then stir and react for 1 - 2 h. Then add the aqueous solution of laccase into the reaction kettle, maintain the reaction temperature at 30 - 40 °C, and react for 2 - 4 h to obtain an intermediate solution; C. Transfer the intermediate solution to a centrifuge tube. Under nitrogen protection, centrifuge at a speed of 3000 - 5000 r / min for 10 - 15 min to separate out the solid precipitate. Then wash the solid precipitate and dry it under a nitrogen atmosphere to obtain the modified bentonite.

3. The sewage treatment agent for high suspended solids in oil production plants according to claim 2, wherein: In step A, the concentration of the aqueous solution of laccase is 10 - 50 mg / mL; the concentration of the ethanol dispersion of nano zero - valent iron is 5 - 20 mg / mL; the mass concentration of the bentonite suspension is 5% - 10%.

4. A sewage treatment agent for high suspended solids in an oil production plant according to claim 2, characterized in that: In step B, the mass ratio of the bentonite suspension, the ethanol dispersion of nano zero - valent iron and the aqueous solution of laccase is 10:(0.5 - 1):(1 - 2).

5. A sewage treatment agent for high suspended solids in an oil production plant according to claim 1, characterized in that The activated biochar material is prepared by the following method: Heat the waste biomass at 180 - 190 °C and an oxygen volume concentration of 1% - 5% for 2 - 3 h to obtain semi - carbonized biomass. Then soak the semi - carbonized biomass with potassium hydroxide solution for 12 - 24 h. After soaking, dry the semi - carbonized biomass, and then calcine it at 450 - 600 °C for 1 - 2 h under an anaerobic condition to obtain the activated biochar material.

6. The sewage treatment agent for high suspended solids in an oil production plant according to claim 5, wherein, The mass concentration of the potassium hydroxide solution is 30% - 40%, and the mass ratio of the semi - carbonized biomass to the potassium hydroxide solution is 1:(3 - 4).

7. A sewage treatment agent for high suspended solids in an oil production plant according to claim 5, characterized in that The waste biomass is any one of rice husk, corn straw and bagasse.

8. A sewage treatment agent for high suspended solids in an oil production plant according to claim 1, characterized in that, The flocculant is any one of polyferric chloride or polyacrylamide.

9. A sewage treatment agent for high suspended solids in oil production plants according to claim 1, characterized in that, The viscosity of the chitosan is 0.7 - 1 Pa·s.

10. A preparation method of a sewage treatment agent for high suspended solids in an oil production plant according to any one of claims 1-9, characterized in that, It includes the following steps: S1. Mix the modified bentonite and the activated biochar material, and stir at a speed of 100 - 150 r / min for 5 - 10 min to obtain a premix; S2. Mix ferrous sulfate, ferric aluminum sulfate, ethylenediaminetetraacetic acid, chitosan and the flocculant with the premix and continue to stir for 20 - 30 min to obtain a mixture; S3. Transfer the mixture to an extrusion granulator for extrusion granulation to obtain granular medicament, and dry the granular medicament at 60 - 80 °C for 3 - 5 h to obtain the medicament for treating high-suspended solid sewage in oil production plants.

Images