Macromolecule / small molecule complex surfactant for enhancing cleaning of oily sludge

Abstract

This invention belongs to the field of oily sludge cleaning technology, specifically a macromolecular / small molecule composite surfactant for enhanced cleaning of oily sludge. A macromolecular surfactant is synthesized by mixing a main monomer (such as acrylamide), a hydrophilic monomer (such as 2-acrylamido-2-methylpropanesulfonic acid), and a hydrophobic monomer (such as long-chain alkyl methacrylate) through free radical polymerization. The unique long-chain structure of this macromolecular surfactant can form larger micelles, effectively encapsulating colloids and asphaltenes. When used in combination with a small molecule surfactant, it forms mixed micelles with stronger solubilizing capabilities, achieving highly efficient removal of colloids and asphaltenes from high-to-medium concentration oily sludge, thereby improving the removal rate of total petroleum hydrocarbons. This invention provides a new technology for the efficient and deep treatment of high-to-medium concentration oily sludge.

Description

Technical Field

[0001] This invention relates to the field of sludge harmless treatment technology, specifically to a macromolecular / small molecule composite surfactant for enhancing the cleaning of oily sludge. Background Technology

[0002] Oily sludge is mainly generated during the extraction, refining, and storage of crude oil, and is a complex mixture composed of crude oil, water, and solid particles. Domestic and international methods for remediating high-concentration oily sludge primarily involve "chemical cleaning-thermal desorption" or "chemical cleaning-microbial treatment." The role of chemical cleaning is to remove high concentrations of petroleum hydrocarbons and create conditions for subsequent treatment. The key to chemical cleaning lies in the selection of cleaning agents. Currently, commonly used small-molecule surfactants (Mr < 1000) for cleaning high-concentration oily sludge include anionic surfactants (such as sodium dodecylbenzenesulfonate (SDBS) and sodium dodecyl sulfate (SDS)), nonionic surfactants (such as Triton X~100 (TX100) and Tween 80), and anionic / nonionic composite surfactants (such as SDBS + TX100). Surfactant elution mainly works through emulsification and solubilization, removing petroleum from the sludge surface while simultaneously recovering petroleum resources. However, small-molecule surfactants have significant limitations in cleaning high-concentration oily sludge due to their molecular structure (short hydrophobic chains, small micelle volume): they struggle to effectively penetrate the oil-solid interface film or fully encapsulate large-molecule colloids and asphaltenes. Small-molecule surfactants are more effective at cleaning light components (saturated hydrocarbons, aromatic hydrocarbons) in oily sludge, but they are less effective at removing total petroleum hydrocarbons (TPH). Oily sludge cleaned with these small-molecule surfactants often retains large-molecule petroleum hydrocarbons, making subsequent thermal desorption and biodegradation difficult to remediate to acceptable levels.

[0003] Recent studies have shown that macromolecular surfactants (MS) have significant advantages in cleaning high-concentration oily sludge. Domestic and international research on MS mainly focuses on polyacrylamide derivatives and modified cellulose derivatives. The advantages of MS are as follows: it can significantly reduce the oil-water interfacial tension, making it easier for asphaltene (TPH) to desorb from the soil particle surface; its molecular structure can form larger micelles, effectively encapsulating colloids and asphaltenes, and exhibiting stronger solubilizing ability for TPH. Studies have found that although hydrophobically modified cellulose derivatives possess many of the advantages of macromolecular surfactants, their removal effect on heavy components such as colloids and asphaltenes in oily sludge is limited. When treating oily sludge with high heavy component content, this type of surfactant still has limitations: difficulty in stripping heavy oil from the soil surface; limited emulsifying and solubilizing ability leading to easy redeposition of oil; and poor molecular permeability affecting deep cleaning effects. Furthermore, its preparation process is complex, requiring high technology and cost. Hydrophobically modified polyacrylamide (HMPAM) is produced by grafting hydrophobic groups (such as long-chain alkyl groups) onto the acrylamide backbone. These long hydrophobic chains can embed into the hydrophobic core of gums and asphaltenes through hydrophobic interactions (such as van der Waals forces and hydrogen bonds), enhancing their stripping from the oil sludge surface. Furthermore, the larger molecular weight of HMPAM allows for the formation of larger micelles, effectively encapsulating the stripped oil droplets and achieving highly efficient removal of gums and asphaltenes. In addition, HMPAM can be prepared via free radical polymerization, a simple and low-cost process suitable for large-scale application. Macromolecular surfactants, with their multifunctional structure, combine hydrophobic segments to strip the oil phase and hydrophilic segments to enhance the dispersion in the aqueous phase, thus strengthening the removal of gums and asphaltenes from oily sludge. Small molecule surfactants, due to their short chains and high interfacial activity, can quickly penetrate the oil-solid interface, breaking the oil-soil bond by reducing interfacial tension, thereby achieving rapid stripping of the oil phase. When used in combination, the two can achieve both efficient stripping and stable dispersion of the oil phase, forming a mixed micelle structure with stronger solubilization ability and higher stability, which significantly improves the cleaning efficiency of high-concentration oily sludge. However, there are currently no reports on the use of macromolecular / small molecule composite surfactants to clean oily sludge. Summary of the Invention

[0004] The purpose of this invention is to provide a macromolecular / small molecule composite surfactant for enhanced cleaning of oily sludge. The macromolecular surfactant incorporates a hydrophobic monomer, a long-chain alkyl methacrylate, during its preparation. This structure, lacking a benzene ring, can embed itself into the hydrophobic core of gums and asphaltenes through hydrophobic interactions (such as van der Waals forces and hydrogen bonds), thereby enhancing the stripping ability of this component from the oily sludge surface and improving the total petroleum hydrocarbon removal rate. The small molecule surfactant is a nonionic surfactant.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A macromolecular / small molecule composite surfactant for enhancing the cleaning of oily sludge is obtained by free radical polymerization of acrylamide as the main monomer, 2-acrylamido-2-methylpropanesulfonic acid as the hydrophilic monomer, and long-chain alkyl methacrylate as the hydrophobic monomer. The macromolecular surfactant is prepared by mixing the macromolecular surfactant and nonionic surfactant in a mass ratio of 1:1 to 10:1 to obtain the macromolecular / small molecule composite surfactant.

[0007] Furthermore, in the preparation process of the macromolecular surfactant, acrylamide accounts for 60% to 80% of the total monomer mass fraction, 2-acrylamido-2-methylpropanesulfonic acid accounts for 10% to 30% of the total monomer mass fraction, and long-chain alkyl methacrylate accounts for 5% to 20% of the total monomer mass fraction. The total monomer is the sum of the main monomer, hydrophilic monomer, and hydrophobic monomer, and the total mass fraction of the three monomers is 100%.

[0008] Furthermore, the structural formula of the macromolecular surfactant is as follows:

[0009]

[0010] In the formula, x=60~70%, y=15~25%, z=5~15%, x+y+z=1, a=10~16.

[0011] Further, the long-chain alkyl methacrylate is at least one of octadecyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate, or hexadecyl methacrylate; the nonionic surfactant is at least one of Triton 100, Tween 60, or Tween 80.

[0012] Furthermore, the preparation process of the macromolecular surfactant is as follows:

[0013] First, weigh the main monomer acrylamide and the hydrophilic monomer 2-acrylamido-2-methylpropanesulfonic acid in a mass ratio of 6:1 to 6:3, add them to deionized water and mix, and adjust to a weakly alkaline state.

[0014] Subsequently, an emulsifier is added and stirred until completely dissolved. Then, the hydrophobic monomer long-chain alkyl methacrylate is added. The mass ratio of the emulsifier to the main monomer acrylamide is 1:1000 to 10:1000, and the mass ratio of the main monomer acrylamide to the long-chain alkyl methacrylate is 6:0.5 to 6:2.

[0015] Next, nitrogen gas is introduced to purge and deoxygenate the system, and then ammonium persulfate initiator is slowly added dropwise. The mass ratio of ammonium persulfate initiator to the main monomer acrylamide is 3:1000~9:1000. After the addition is complete, the mixture is stirred for 25~40 min.

[0016] After stirring, the system is heated to 60-90℃ and reacted for 4-6 h with stirring. After the reaction is complete, the product is collected and dried at 30-80℃ for 20-36 h to obtain the macromolecular surfactant HMPAM.

[0017] Preparation of macromolecular / small molecule composite surfactant: The macromolecular surfactant HMPAM prepared above and the small molecule surfactant are compounded in a certain mass ratio to obtain a macromolecular / small molecule composite surfactant that enhances the cleaning of oily sludge. The small molecule surfactant is selected from nonionic surfactants (such as Triton 100, Tween 60, or Tween 80).

[0018] The macromolecular surfactant prepared in this invention is anionic. Nonionic small-molecule surfactants have low critical micelle concentrations and good solubilizing abilities; therefore, they are chosen to be compounded with the macromolecular surfactant synthesized in this invention. The two can exert a synergistic effect and enhance the cleaning effect on oily sludge.

[0019] Furthermore, the macromolecular / small molecule composite surfactant is used to clean oily sludge.

[0020] Furthermore, the process of using the macromolecular / small molecule composite surfactant to clean oily sludge is as follows: oily sludge with an oil content of 15%wt~20%wt is placed in a reactor, and the macromolecular / small molecule composite surfactant and water are added for cleaning. The mass ratio of the composite surfactant to the oily sludge is 1:100~10:100, the cleaning temperature is 50~90℃, the rotation speed is 100~150 rpm, and the cleaning time is 0.5~2 h.

[0021] Alternatively, the macromolecular / small molecule composite surfactant can be mixed with water to obtain a composite surfactant solution with a concentration of 1~5 g / L. Then, the composite surfactant solution can be added to oily sludge with an oil content of 15%wt~20%wt for cleaning. The cleaning conditions are: cleaning temperature 50~90℃, rotation speed 100~150 rpm, and cleaning time 0.5~2 h.

[0022] Furthermore, during the cleaning process, an auxiliary agent is added, which is at least one of sodium carbonate, sodium bicarbonate, or sodium silicate, and the amount of the auxiliary agent added is 1~5 g / L.

[0023] Furthermore, after cleaning the oily sludge, the total petroleum hydrocarbon removal rate in the oily sludge was calculated by gravimetric method, and the removal rates of gum and asphaltenes were measured by stepwise solvent extraction-chromatographic column method; the total petroleum hydrocarbon removal rate was consistently above 65%, and the removal rate of heavy components, including gum and asphaltenes, was controlled above 70%.

[0024] This invention utilizes a macromolecular / small molecule composite surfactant to enhance the removal of heavy components, including colloids and asphaltenes, from oily sludge. Through the synergistic effect of the macromolecular / small molecule composite surfactant, it enhances the removal of total petroleum hydrocarbons, especially the removal of colloids and asphaltenes in oily sludge, thereby achieving efficient cleaning of high-to-medium concentration oily sludge.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1) The macromolecular surfactant in the macromolecular / small molecule composite surfactant of this invention is a hydrophobic monomer with long-chain alkyl methacrylate. This structure can be embedded into the hydrophobic core of colloids and asphaltenes through hydrophobic interactions (such as van der Waals forces and hydrogen bonds), making it easier for colloids and asphaltenes to desorb from the oil sludge. Combined with the high molecular weight of HMPAM, it can form larger micelles, which can effectively encapsulate the stripped oil droplets, thereby achieving efficient removal of colloids and asphaltenes from oil sludge.

[0027] 2) In this invention, the synthesized macromolecular surfactant HMPAM is compounded with a small molecule surfactant (nonionic surfactant TX100) to obtain the macromolecular / small molecule composite surfactant. Under the conditions of a composite surfactant solution concentration of 3 g / L, a temperature of 75℃, a cleaning time of 1 h, and a rotation speed of 120 rpm, oily sludge was cleaned. Compared with the traditional small molecule composite surfactant (SDBS+TX100) under the same conditions, the total petroleum hydrocarbon (TPH) removal rate was increased by 38.6%, and the gum and asphaltenes removal rates were increased by 80.7% and 61.2%, respectively. Specific experimental data are shown in Table 1.

[0028] Table 1. Comparison of the effects of macromolecular and small molecule composite surfactants with traditional small molecule composite surfactants

[0029]

[0030] 3) The process of this invention is simple, the cost is low, and the cleaning effect is good. It can be applied on a large scale to the efficient cleaning of high-concentration oily sludge. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments, but these are not intended to limit the scope of protection of the present invention.

[0032] This invention utilizes acrylamide as the main monomer, 2-acrylamido-2-methylpropanesulfonic acid as the hydrophilic monomer, and long-chain alkyl methacrylate as the hydrophobic monomer. Through free radical polymerization, a novel hydrophobically modified polyacrylamide-based macromolecular surfactant is obtained. The long-chain alkyl methacrylate in this macromolecular surfactant can bind to heavy components such as colloids and asphaltenes in oily sludge through hydrophobic interactions, inserting itself into their aggregates and disrupting intermolecular forces, thereby promoting oil desorption from the soil particle surface. Simultaneously, the steric hindrance effect generated by the macromolecular skeleton can further inhibit oil droplet collision and aggregation, enhancing the removal efficiency of heavy components and ultimately significantly improving the total petroleum hydrocarbon removal efficiency.

[0033] The above-mentioned macromolecular / small molecule composite surfactant was used to clean oily sludge: A certain mass of oily sludge with an oil content of 15% wt to 20% wt was placed in a reactor, and an appropriate mass of macromolecular / small molecule composite surfactant (the mass ratio of composite surfactant to oily sludge was 1:100 to 10:100) was added, along with an appropriate amount of water. The cleaning was carried out at a cleaning temperature of 50 to 90℃ and a rotation speed of 100 to 150 rpm for 0.5 to 2 hours. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH content of the oily sludge was determined by gravimetric method, and the TPH removal rate was calculated. The four components of crude oil were determined by stepwise solvent extraction-chromatographic column method.

[0034] In the examples below, the mass ratio of emulsifier to main monomer is 3:1000, and the mass ratio of initiator ammonium persulfate to main monomer is 5:1000. Unless otherwise specified, all "%" in this invention refers to mass percentage.

[0035] Example 1

[0036] Preparation of macromolecular surfactant: Acrylamide, the main monomer, and 2-acrylamido-2-methylpropanesulfonic acid, the hydrophilic monomer, were added to deionized water at a mass ratio of 6:3. The pH of the solution was adjusted to 8.0. Sodium dodecyl sulfate, the emulsifier, was added and stirred until completely dissolved. Then, hexadecyl methacrylate, the hydrophobic monomer, was added, with a mass ratio of acrylamide to hexadecyl methacrylate of 6:1. The system was purged with nitrogen to remove oxygen, and then ammonium persulfate, the initiator, was slowly added dropwise. After the addition was complete, the mixture was stirred continuously for 30 min. After stirring was complete, the system was heated to the reaction temperature of 80 °C and reacted for 6 h with stirring. After the reaction was completed, the product was collected and dried at 50 °C for 25 h to obtain the macromolecular surfactant HMPAM. The yield of HMPAM was above 92%.

[0037] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0038] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 84.5% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 89.5% and 91.2%, respectively, by stepwise solvent extraction-chromatographic column method.

[0039] Example 2

[0040] Preparation of macromolecular surfactants: First, weigh the main monomer acrylamide and the hydrophilic monomer 2-acrylamido-2-methylpropanesulfonic acid at a mass ratio of 6:2, add them to deionized water and mix, and adjust to a weakly alkaline pH of 7.0;

[0041] Subsequently, an emulsifier was added and stirred until completely dissolved, followed by the addition of the hydrophobic monomer dodecyl methacrylate; wherein the mass ratio of emulsifier to main monomer was 3:1000; and the mass ratio of main monomer acrylamide to dodecyl methacrylate was 6:0.5.

[0042] Next, nitrogen gas was introduced to purge and deoxygenate the system, and then ammonium persulfate initiator was slowly added dropwise. The mass ratio of ammonium persulfate initiator to main monomer was 5:1000. After the addition was completed, the mixture was stirred for 30 min.

[0043] After stirring, the system was heated to 80°C and reacted for 6 h with stirring. After the reaction was completed, the product was collected and dried at 50°C for 25 h to obtain the macromolecular surfactant HMPAM.

[0044] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0045] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 66.5% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 70.5% and 71.2%, respectively, by stepwise solvent extraction-chromatographic column method.

[0046] Example 3

[0047] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 2, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and tetradecyl methacrylate is 6:1:1.

[0048] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0049] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 72.5% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 78.3% and 80.7%, respectively, by stepwise solvent extraction-chromatographic column method.

[0050] Example 4

[0051] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 2, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and hexadecyl methacrylate is 6:2:1.

[0052] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0053] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 86.4% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 89.8% and 92.0%, respectively, by stepwise solvent extraction-chromatographic column method.

[0054] Example 5

[0055] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 1, except that the hydrophobic monomer is octadecyl methacrylate and the pH of the solution is adjusted to 6.0.

[0056] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 1:1 to obtain macromolecular / small molecule composite surfactant.

[0057] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 86.9% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 89.2% and 91.7%, respectively, by stepwise solvent extraction-chromatographic column method.

[0058] Example 6

[0059] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 4, except that the macromolecular / small molecule composite surfactant is prepared by mixing HMPAM and TX100 in a mass ratio of 3:1 to obtain the macromolecular / small molecule composite surfactant.

[0060] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 82.7% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 85.5% and 90.6%, respectively, by stepwise solvent extraction-chromatographic column method.

[0061] Example 7

[0062] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 1, except that the macromolecular / small molecule composite surfactant is prepared by mixing HMPAM and TX100 in a mass ratio of 5:1 to obtain the macromolecular / small molecule composite surfactant.

[0063] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 78.7% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 83.1% and 86.5%, respectively, by stepwise solvent extraction-chromatographic column method.

[0064] Example 8

[0065] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 1, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and hexadecyl methacrylate is 10:2:1, and the pH of the solution is adjusted to 7.0.

[0066] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 10:1 to obtain macromolecular / small molecule composite surfactant.

[0067] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 75.2% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 78.8% and 81.9%, respectively, by stepwise solvent extraction-chromatographic column method.

[0068] Example 9

[0069] The preparation processes of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment are the same as in Example 1. The difference lies in the cleaning process of the oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel, and 200 g of macromolecular / small molecule composite surfactant, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75°C and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 68.6% by gravimetric method, and the removal rates of colloids and asphaltenes were 73.8% and 77.5%, respectively, as determined by stepwise solvent extraction-chromatographic column method.

[0070] Example 10

[0071] The preparation processes of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment are the same as in Example 1. The difference lies in the cleaning process of the oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel, and 1000 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 87.9% by gravimetric method, and the removal rates of colloids and asphaltenes were 90.8% and 93.9%, respectively, as determined by stepwise solvent extraction-chromatographic column method.

[0072] Example 11

[0073] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 2, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and octadecyl methacrylate is 5:2:1, and the pH of the solution is adjusted to 7.5.

[0074] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0075] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 50℃ and 100 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 88.3% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 90.5% and 92.1%, respectively, by stepwise solvent extraction-chromatographic column method.

[0076] Example 12

[0077] The preparation process of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment is the same as in Example 11, except that the pH of the solution is adjusted to 6.0.

[0078] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 90℃ and 150 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 89.7% by gravimetric method. The removal rates of colloids and asphaltenes were 91.6% and 94.2%, respectively, as determined by stepwise solvent extraction-chromatographic column method.

[0079] Example 13

[0080] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 2, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and hexadecyl methacrylate is 5:2:1, and the pH of the solution is adjusted to 7.5.

[0081] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0082] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 75℃ and 120 rpm for 0.5 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 83.3% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 86.7% and 90.1%, respectively, by stepwise solvent extraction-chromatographic column method.

[0083] Example 14

[0084] The preparation process of the macromolecular surfactant in this embodiment is the same as in Example 2, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and octadecyl methacrylate is 5:2:1, and the pH of the solution is adjusted to 8.0.

[0085] Preparation of macromolecular / small molecule composite surfactant: HMPAM and TX100 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0086] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of pure water were added. The mixture was then washed at 75℃ and 120 rpm for 2 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 84.4% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 89.5% and 93.1%, respectively, by stepwise solvent extraction-chromatographic column method.

[0087] Example 15

[0088] The preparation processes of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment are the same as in Example 14. The difference lies in the cleaning process of the oily sludge: 10 kg of oily sludge with an oil content of 20% wt and a water content of 45% wt was placed in a reaction vessel, and 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. Subsequently, the sludge was cleaned at 75°C and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 80.9% by gravimetric method, and the removal rates of colloids and asphaltenes were measured to be 87.7% and 89.2%, respectively, by stepwise solvent extraction-chromatographic column method.

[0089] Example 16

[0090] The preparation processes of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment are the same as in Example 1, except that the macromolecular / small molecule composite surfactants are first mixed with water to obtain a composite surfactant solution with a concentration of 1 g / L. The volume ratio of the composite surfactant solution to the mass of the oily sludge is 20 L: 1 kg. Then, the composite surfactant solution is added to the oily sludge with an oil content of 15% wt for washing. The washing conditions are: washing temperature 75℃, rotation speed 120 rpm, and washing time 1 h. After the reaction, the soil solids are collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge is calculated to be 75.3% by gravimetric method. The removal rates of colloids and asphaltenes are measured to be 82.9% and 85.9% by stepwise solvent extraction-chromatographic column method, respectively.

[0091] Example 17

[0092] The preparation processes of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment are the same as in Example 1. The difference is that the macromolecular / small molecule composite surfactants are first mixed with water to obtain a composite surfactant solution with a concentration of 5 g / L. Then, the composite surfactant solution is added to oily sludge with an oil content of 15% wt for washing. The volume ratio of the composite surfactant solution to the mass of the oily sludge is 20 L: 1 kg. The washing conditions are: washing temperature 75℃, rotation speed 120 rpm, and washing time 1 h. After the reaction, the soil solids are collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge is calculated to be 85.1% by gravimetric method. The removal rates of colloids and asphaltenes are measured to be 90.6% and 91.5% by stepwise solvent extraction-chromatographic column method, respectively.

[0093] Example 18

[0094] The preparation process of the macromolecular surfactant in this embodiment is the same as that in Example 1, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and octadecyl methacrylate is 8:2:1, and the pH of the solution is adjusted to 7.0.

[0095] Preparation of macromolecular / small molecule composite surfactant: HMPAM and Tween 60 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0096] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried. The TPH removal rate in the oily sludge was calculated to be 84.9% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 89.5% and 92.3%, respectively, by stepwise solvent extraction-chromatographic column method.

[0097] Example 19

[0098] The preparation process of the macromolecular surfactant in this embodiment is the same as that in Example 1, except that the mass ratio of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid and hexadecyl methacrylate is 6:2:1, and the pH of the solution is adjusted to 7.0.

[0099] Preparation of macromolecular / small molecule composite surfactant: HMPAM and Tween 80 were compounded at a mass ratio of 2:1 to obtain macromolecular / small molecule composite surfactant.

[0100] Cleaning of oily sludge: 10 kg of oily sludge with an oil content of 15% wt and a water content of 45% wt was placed in a reaction vessel. 600 g of the macromolecular / small molecule composite surfactant prepared above, 600 g of sodium silicate, and 200 L of water were added. The mixture was then washed at 75℃ and 120 rpm for 1 h. After the reaction, the soil solids were collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge was calculated to be 85.5% by gravimetric method. The removal rates of colloids and asphaltenes were determined to be 90.4% and 91.2%, respectively, by stepwise solvent extraction-chromatographic column method.

[0101] Example 20

[0102] The preparation processes of macromolecular surfactants and macromolecular / small molecule composite surfactants in this embodiment are the same as in Example 5, except that HMPAM and TX100 are compounded at a mass ratio of 2:1. The macromolecular / small molecule composite surfactant is first mixed with water to obtain a composite surfactant solution with a concentration of 3 g / L. Then, the composite surfactant solution is added to oily sludge with an oil content of 15%wt for washing. The volume ratio of the composite surfactant solution to the mass of the oily sludge is 20 L:1 kg. The washing conditions are: washing temperature 75℃, rotation speed 120 rpm, and washing time 1 h. After the reaction, the soil solids are collected by centrifugation and air-dried naturally. The TPH removal rate in the oily sludge is calculated to be 87.5% by gravimetric method. The removal rates of colloids and asphaltenes are measured to be 89.5% and 93.2% by stepwise solvent extraction-chromatographic column method, respectively.

[0103] Comparative Example 1

[0104] The preparation steps of the macromolecular surfactant in this comparative example are the same as those in Example 4, except that the hydrophobic monomer is octyl methacrylate and the hydrophilic monomer is sodium α-olefin sulfonate.

[0105] The preparation of the macromolecular / small molecule composite surfactant and the process for cleaning oily sludge were the same as in Example 4. The difference lay in the use of different hydrophilic and hydrophobic monomers in the preparation of the macromolecular surfactant. The TPH removal rate in the oily sludge was calculated to be 45.6% by gravimetric method, and the removal rates of colloids and asphaltenes were 32.3% and 40.5%, respectively, as determined by stepwise solvent extraction-chromatographic column method.

[0106] Comparative Example 2

[0107] The steps for preparing the macromolecular surfactant in this comparative example are the same as in Example 4, except that the hydrophobic monomer is hexyl methacrylate and the hydrophilic monomer is sodium α-olefin sulfonate.

[0108] The preparation of the macromolecular / small molecule composite surfactant and the process for cleaning oily sludge were the same as in Example 4. The difference lay in the use of different hydrophilic and hydrophobic monomers in the preparation of the macromolecular surfactant. The TPH removal rate in the oily sludge was calculated to be 40.1% by gravimetric method, and the removal rates of colloids and asphaltenes were 28.8% and 33.7%, respectively, as determined by stepwise solvent extraction-chromatographic column method.

[0109] Comparative Example 3

[0110] The steps for preparing the macromolecular surfactant in this comparative example are the same as in Example 4, except that the hydrophobic monomer is octyl methacrylate.

[0111] The preparation of the macromolecular / small molecule composite surfactant and the process for cleaning oily sludge were the same as in Example 4. The difference was that the hydrophobic monomer used to prepare the macromolecular surfactant was different. The TPH removal rate in the oily sludge was calculated to be 54.2% by gravimetric method, and the removal rates of colloids and asphaltenes were 47.8% and 50.7%, respectively, as determined by stepwise solvent extraction-chromatographic column method.

[0112] Under the same conditions, the macromolecular surfactant prepared in Example 4, compared with the macromolecular surfactants prepared in Comparative Examples 1-3, showed better cleaning effect on oily sludge when combined with small molecule surfactants. In the examples, the TPH removal rate consistently reached over 65%, and the removal rate of heavy components (colloids, asphaltenes) also exceeded 70%; the present invention shows a more significant effect in cleaning heavy components.

[0113] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A macromolecular / small molecule composite surfactant for enhancing the cleaning of oily sludge, characterized in that, A macromolecular surfactant is obtained by free radical polymerization using acrylamide as the main monomer, 2-acrylamido-2-methylpropanesulfonic acid as the hydrophilic monomer, and long-chain alkyl methacrylate as the hydrophobic monomer. The macromolecular surfactant and nonionic surfactant are then formulated in a mass ratio of 1:1 to 10:1 to obtain the macromolecular / small molecule composite surfactant. The structural formula of the macromolecular surfactant is: ， In the formula, x=60~70%, y=15~25%, z=5~15%, x+y+z=1, a=10~16.

2. The macromolecular / small molecule composite surfactant for enhancing the cleaning of oily sludge according to claim 1, characterized in that, The long-chain alkyl methacrylate is at least one of octadecyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate, or hexadecyl methacrylate; the nonionic surfactant is at least one of Triton 100, Tween 60, or Tween 80.

3. The macromolecular / small molecule composite surfactant for enhancing the cleaning of oily sludge according to claim 1, characterized in that, The preparation process of the macromolecular surfactant is as follows: First, weigh the main monomer acrylamide and the hydrophilic monomer 2-acrylamido-2-methylpropanesulfonic acid in a mass ratio of 6:1 to 6:3, add them to deionized water and mix, and adjust to a weakly alkaline state. Subsequently, an emulsifier is added and stirred until completely dissolved. Then, the hydrophobic monomer long-chain alkyl methacrylate is added. The mass ratio of the emulsifier to the main monomer acrylamide is 1:1000 to 10:1000, and the mass ratio of the main monomer acrylamide to the long-chain alkyl methacrylate is 6:0.5 to 6:

2. Next, nitrogen gas is introduced to purge and deoxygenate the system, and then ammonium persulfate initiator is slowly added dropwise. The mass ratio of ammonium persulfate initiator to the main monomer acrylamide is 3:1000~9:1000. After the addition is complete, the mixture is stirred for 25~40 min. After stirring, the system is heated to 60-90℃ and reacted for 4-6 h with stirring. After the reaction is complete, the product is collected and dried at 30-80℃ for 20-36 h to obtain the macromolecular surfactant HMPAM.

4. The application of the macromolecular / small molecule composite surfactant for cleaning oily sludge as described in any one of claims 1 to 3.

5. The application according to claim 4, characterized in that, The process of using the macromolecular / small molecule composite surfactant to clean oily sludge is as follows: oily sludge with an oil content of 15%wt~20%wt is placed in a reactor, and the macromolecular / small molecule composite surfactant and water are added for cleaning. The mass ratio of the composite surfactant to the oily sludge is 1:100~10:100, the cleaning temperature is 50~90℃, the rotation speed is 100~150 rpm, and the cleaning time is 0.5~2 h. Alternatively, the macromolecular / small molecule composite surfactant can be mixed with water to obtain a composite surfactant solution with a concentration of 1~5 g / L. Then, the composite surfactant solution can be added to oily sludge with an oil content of 15%wt~20%wt for cleaning. The cleaning conditions are: cleaning temperature 50~90℃, rotation speed 100~150 rpm, and cleaning time 0.5~2 h.

6. The application according to claim 5, characterized in that, During the cleaning process, an auxiliary agent is added, which is at least one of sodium carbonate, sodium bicarbonate or sodium silicate, and the amount of the auxiliary agent added is 1~5 g / L.

7. The application according to claim 6, characterized in that, After cleaning the oily sludge, the total petroleum hydrocarbon removal rate in the oily sludge was calculated by gravimetric method, and the removal rates of gum and asphaltenes were measured by stepwise solvent extraction-chromatographic column method. The total petroleum hydrocarbon removal rate was consistently above 65%, and the removal rate of heavy components, including gum and asphaltenes, was controlled above 70%.

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