Oil-containing scum dewatering agent

Abstract

The present application relates to a kind of oil-containing dregs dehydrating agent, comprising: multi-branched demulsifier, double quaternary ammonium salt surfactant, flocculating agent and water;The multi-branched demulsifier is first by triethylene tetramine as reaction initiator, methyl acrylate is monomer by Michael addition reaction and amidation reaction to prepare hyperbranched polyamide-amine;Then under alkaline conditions, propylene oxide, ethylene oxide, propylene oxide is sequentially added to obtain polymerization;The double quaternary ammonium salt surfactant is with rhamnolipid as starting material, acyl chloride reaction is carried out using its terminal carboxyl group first, then amidation reaction is introduced amino, and then with ammonium bromide salt formation.The dehydrating agent of the present application is mixed by multi-branched demulsifier, double quaternary ammonium salt surfactant, flocculating agent and water in specific proportion, with the characteristics of strong demulsification ability, good flocculation effect, can be used to handle the oil-containing dregs of complex components generated in refinery, and the amount of dehydrating agent is less, and dehydration efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of environmental pollution treatment agents, and more specifically, to an oily scum dehydrating agent. Background Technology

[0002] Oily sludge refers to the oily sludge produced in the flotation stage of petrochemical wastewater treatment plants. After flocculants are added, oil droplets and solid particles in the water adhere to tiny air bubbles and are carried to the surface. It is mainly composed of negatively charged hydrophilic colloidal particles, has a complex composition, is difficult to dewater, and its volume increases significantly as the quality of the crude oil deteriorates. Currently, companies typically mix the sludge with other oily sludge, add flocculants, and then mechanically separate and dewater it until the water content is reduced to about 85% before landfilling it as hazardous waste. Due to severe emulsification of the sludge, the dewatering effect of existing processes is limited, and crude oil recovery is difficult, increasing the company's hazardous waste treatment burden and wasting crude oil resources. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide an oily scum dehydrating agent, which is composed of demulsifier, flocculant and surfactant, and has a good dehydration effect.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] An oily scum dewatering agent, comprising, by weight percentage:

[0006] 40-70% multi-branched demulsifier, 20-40% quaternary ammonium salt surfactant, 10% flocculant and the balance water;

[0007] The multi-branched demulsifier is first prepared by using triethylenetetramine as a reaction initiator and methyl acrylate as a monomer through Michael addition reaction and amidation reaction to obtain hyperbranched polyamide-amine; then, under alkaline conditions, propylene oxide, ethylene oxide and propylene oxide are added sequentially to polymerize and obtain a multi-branched polyether type demulsifier.

[0008] The preparation process of the bisquaternary ammonium salt surfactant is as follows:

[0009] S1. Add rhamnolipid and a catalytic amount of DMAP to the reaction flask, and add thionyl chloride dropwise to carry out the acyl chloride reaction. The product after the reaction is completed is dissolved in dichloromethane and placed in an ice-water bath for later use.

[0010] S2. Dissolve methyl 6-aminohexanoate hydrochloride and triethylamine in dichloromethane, and then slowly add them dropwise to step S1. After the addition is complete, heat to 30°C and continue stirring for 24 hours. Add sodium hydroxide solution, collect the organic phase, dry and filter, and use the product for later use.

[0011] S3. Dissolve the product of step S2 in dichloromethane and place it in an ice-water bath. Under nitrogen protection, slowly add 3-dimethylaminopropylamine dropwise. After the addition is complete, move the mixture to room temperature and continue stirring for 24 hours. Distill under reduced pressure to obtain a viscous liquid.

[0012] S4. Dissolve the viscous liquid from step S3 in ethanol, then add 3-bromo-propyltrimethylammonium bromide, heat to 90°C and stir for 24 hours, cool to room temperature, remove the solvent by vacuum distillation, recrystallize with a mixed solution of ethanol and acetone, and dry to obtain the final product.

[0013] Furthermore, the preparation process of the multi-branched demulsifier is as follows:

[0014] 1) Add a certain amount of triethylenetetramine to a reaction flask, add methanol as a solvent and stir to mix it evenly. Then, under the protection of an ice-water bath and nitrogen, slowly add an equimolar amount of methyl acrylate. After the addition is complete, heat to 35°C and stir for 48 h. Then, heat to 60, 80, 100, 120 and 140°C in stages and react for 2 h each time. Vacuum is drawn during the reaction. The resulting viscous liquid is hyperbranched polyamide-amine.

[0015] 2) Add hyperbranched polyamide-amine to the reactor, add a catalytic amount of potassium hydroxide, evacuate, heat to 120°C, and then slowly introduce propylene oxide. When the reactor pressure drops to a negative pressure and stabilizes, introduce ethylene oxide and propylene oxide into the reactor in sequence, and react at a constant temperature until the reactor pressure drops to a negative pressure and stabilizes, thus obtaining the product.

[0016] Further, in step 2), the amounts of raw materials added are as follows: 1 part hyperbranched polyamide-amine, 10 parts propylene oxide, 200 parts ethylene oxide, and 200 parts propylene oxide.

[0017] Furthermore, the flocculant is polyacrylamide.

[0018] Furthermore, the flocculant is cationic polyacrylamide.

[0019] Oily sludge from refineries has a complex composition, and it is difficult to achieve the desired dehydration effect using a single demulsifier or flocculant. This application prepares a dual-headed quaternary ammonium salt surfactant and a multi-branched polyether demulsifier, which are combined with cationic polyacrylamide flocculant to form a dehydrating agent with high dehydration efficiency when used to treat oily sludge. Firstly, cationic polyacrylamide is used as a flocculant to flocculate sludge in scum, forming loose small flocs for removal. Secondly, the bisquaternary ammonium salt surfactant is obtained by modifying rhamnolipin, a biodegradable biosurfactant with demulsifying properties. Through modification, a bisquaternary ammonium salt is grafted onto its surface, resulting in high solubility and adsorption bridging, further promoting flocculation. Thirdly, the multi-branched demulsifier is based on hyperbranched polyamide-amine polymers, utilizing the amino groups on the chains as active sites to polymerize PEO-PPO-PEO chains. Multiple branched polyether chains diffuse out from the hyperbranched polymer chain structure, making it more conducive to contact with oil droplet surfaces in three-dimensional space. With the synergistic effect of the bisquaternary ammonium salt surfactant reducing the interfacial film strength, it can also disperse more quickly at the oil-water interface, promoting oil droplet co-aggregation, improving demulsification efficiency, and facilitating oil-water separation.

[0020] Compared with the prior art, the beneficial effects of the present invention are: the dehydrating agent of the present invention is made by mixing multi-branched demulsifier, quaternary ammonium salt surfactant, flocculant and water in a specific ratio, and has the characteristics of strong demulsification ability and good flocculation effect. It can be used to treat oily sludge with complex composition generated by refineries. The amount of dehydrating agent used is small and the dehydration efficiency is high. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] Example:

[0024] An oily scum dewatering agent, comprising, by weight percentage:

[0025] 40-70% multi-branched demulsifier, 20-40% quaternary ammonium salt surfactant, 10% cationic polyacrylamide flocculant, and the balance water;

[0026] The preparation process of the multi-branched demulsifier is as follows:

[0027] 1) Add a certain amount of triethylenetetramine to a reaction flask, add methanol as a solvent and stir to mix it evenly. Then, under the protection of an ice-water bath and nitrogen, slowly add an equimolar amount of methyl acrylate. After the addition is complete, heat to 35°C and stir for 48 h. Then, heat to 60, 80, 100, 120 and 140°C in stages and react for 2 h each time. Vacuum is drawn during the reaction. The resulting viscous liquid is hyperbranched polyamide-amine.

[0028] 2) Add 1 part of hyperbranched polyamide-amine to the reactor, add a catalytic amount of potassium hydroxide, evacuate, heat to 120°C, and then slowly introduce 10 parts of propylene oxide. When the reactor pressure drops to a negative pressure and stabilizes, introduce 200 parts of ethylene oxide and 200 parts of propylene oxide into the reactor in sequence, and react at a constant temperature until the reactor pressure drops to a negative pressure and stabilizes, thus obtaining the product.

[0029] The preparation process of the bisquaternary ammonium salt surfactant is as follows:

[0030] S1. Add rhamnolipid and a catalytic amount of DMAP to the reaction flask, and add thionyl chloride dropwise to carry out the acyl chloride reaction. The product after the reaction is completed is dissolved in dichloromethane and placed in an ice-water bath for later use.

[0031] S2. Dissolve methyl 6-aminohexanoate hydrochloride and triethylamine in dichloromethane, and then slowly add them dropwise to step S1. After the addition is complete, heat to 30°C and continue stirring for 24 hours. Add sodium hydroxide solution, collect the organic phase, dry and filter, and use the product for later use.

[0032] S3. Dissolve the product of step S2 in dichloromethane and place it in an ice-water bath. Under nitrogen protection, slowly add 3-dimethylaminopropylamine dropwise. After the addition is complete, move the mixture to room temperature and continue stirring for 24 hours. Distill under reduced pressure to obtain a viscous liquid.

[0033] S4. Dissolve the viscous liquid from step S3 in ethanol, then add 3-bromo-propyltrimethylammonium bromide, heat to 90°C and stir for 24 hours, cool to room temperature, remove the solvent by vacuum distillation, recrystallize with a mixed solution of ethanol and acetone, and dry to obtain the final product.

[0034] Multi-branched demulsifier and bisquaternary ammonium salt surfactant were prepared according to the above preparation process, and then mixed with cationic polyacrylamide and water in a certain proportion to form a dehydrating agent (Examples 1-4). The dehydrating agent was then applied to the dehydration treatment of scum.

[0035] In comparison, this application also obtained Comparative Example 1 by replacing the multi-branched demulsifier with PEO-PPO-PEO, and Comparative Example 2 by replacing the bisquaternary ammonium salt surfactant with rhamnolipid.

[0036] This application focuses on oily scum from the flotation section of Yangzhou Petrochemical. On-site sampling and analysis revealed that the scum's water content was 97%. A dehydrating agent of 10 mg / L was added, and after stirring and settling for 2 hours, the water content of the treated scum was calculated. The water content was determined according to GB / T 260—2016, "Determination of Water Content in Petroleum Products—Distillation Method".

[0037] Table 1

[0038]

[0039] In the table, A:B:C:D represents the mass ratio of multi-branched demulsifier: bisquaternary ammonium salt surfactant: cationic polyacrylamide flocculant: water. In Comparative Example 1, A is PEO-PPO-PEO, and the rest is the same as in Example 2; in Comparative Example 2, B is rhamnolipid, and the rest is the same as in Example 2; in Comparative Example 3, no cationic polyacrylamide is added.

[0040] As shown in Table 1, this application achieved a dehydration rate of over 60% for scum treatment after adding only 10 mg / L and standing for 2 hours. Comparing Comparative Examples 1-3, it can be found that the multi-branched demulsifier played a crucial role in the dehydration process, while the quaternary ammonium salt surfactant and cationic polyacrylamide flocculant also played a synergistic and auxiliary role to a certain extent, ultimately resulting in a high efficiency of the dehydrating agent.

[0041] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details shown and described herein.

Claims

1. An oil-containing dross dehydrator characterized by comprising Comprise, by mass percentage: 40~70% multi-branched demulsifier, 20~40% double quaternary ammonium salt surfactant, 10% flocculant, and the balance of water; The multi-branched demulsifier is first prepared by Michael addition reaction and amidation reaction using triethylenetetramine as a reaction initiator and methyl acrylate as a monomer to obtain a hyperbranched polyamide-amine; then, under alkaline conditions, propylene oxide, ethylene oxide, and propylene oxide are sequentially added to polymerize a multi-branched polyether demulsifier; The preparation process of the double quaternary ammonium salt surfactant is as follows: S1, rhamnolipid and a catalytic amount of DMAP are added to a reaction bottle, and acyl chloride reaction is performed by dropwise adding thionyl chloride; the product after the reaction is completed is dissolved in dichloromethane and placed in an ice water bath for standby; S2, 6-aminohexanoic acid methyl ester hydrochloride and triethylamine are dissolved in dichloromethane, and then slowly added to step S1; after the dropwise addition is completed, the temperature is raised to 30°C and the stirring reaction is continued for 24h; sodium hydroxide solution is added, the organic phase is collected, dried and filtered; and the product is standby; S3, the product of step S2 is dissolved in dichloromethane and placed in an ice water bath; 3-dimethylaminopropylamine is slowly added under nitrogen protection; after the dropwise addition is completed, the temperature is raised to room temperature and the stirring reaction is continued for 24h; and a viscous liquid is obtained by distillation under reduced pressure; S4, the viscous liquid of step S3 is dissolved in ethanol, then 3-bromo-propyl trimethyl ammonium bromide is added, the temperature is raised to 90°C and stirred for 24h; the temperature is lowered to room temperature; the solvent is removed by distillation under reduced pressure; a mixed solution of ethanol and acetone is used for recrystallization; and after drying, the double quaternary ammonium salt surfactant is obtained.

2. The oil-containing scum dewatering agent according to claim 1, characterized by, The preparation process of the multi-branched demulsifier is as follows: 1) a certain amount of triethylenetetramine is added to a reaction bottle, methanol is added as a solvent and stirred to mix uniformly; then, under ice water bath and nitrogen protection, an equal molar amount of methyl acrylate is slowly added dropwise; after the dropwise addition is completed, the temperature is raised to 35°C and the stirring reaction is continued for 48h; then, the temperature is staged to 60, 80, 100, 120, and 140, respectively, and reacted for 2h each time; during the reaction process, vacuum is applied; and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) the hyperbranched polyamide-amine is added to a reaction kettle, a catalytic amount of potassium hydroxide is added, vacuum is applied, the temperature is raised to 120°C, then propylene oxide is slowly introduced; when the kettle pressure drops to negative pressure and stabilizes, ethylene oxide and propylene oxide are sequentially introduced into the kettle; and constant temperature reaction is carried out until the kettle pressure drops to negative pressure and stabilizes.

3. The oil-containing scum dewatering agent according to claim 2, characterized by In step 2), the addition amounts of raw materials are as follows: hyperbranched polyamide-amine 1 part, propylene oxide 10 parts, ethylene oxide 200 parts, and propylene oxide 200 parts.

4. The oil-containing scum dewatering agent according to claim 1, characterized by, The flocculant is polyacrylamide.

5. The oil-containing scum dewatering agent according to claim 1, characterized by, The flocculant is cationic polyacrylamide.

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