Dehydrating agent for oil-containing scum

Abstract

The invention relates to an oil-containing scum dehydrating agent which comprises a multi-branch demulsifier, a biquaternary ammonium salt surfactant, a flocculating agent and water, the preparation method of the multi-branched-chain demulsifier comprises the following steps: firstly, preparing hyperbranched polyamide-amine by taking triethylene tetramine as a reaction initiator and methyl acrylate as a monomer through Michael addition reaction and amidation reaction; and then sequentially adding epoxypropane, ethylene oxide and epoxypropane under an alkaline condition for polymerization to obtain the product. The biquaternary ammonium salt surfactant is formed by taking rhamnolipid as an initial raw material, firstly carrying out acylating chlorination reaction by utilizing terminal carboxyl of the rhamnolipid, then carrying out amidation reaction to introduce amino, and then forming the biquaternary ammonium salt surfactant with ammonium bromide. The dehydrant is formed by mixing the multi-branch demulsifier, the biquaternary ammonium salt surfactant, the flocculant and the water according to a specific proportion, has the characteristics of strong demulsification capability and good flocculation effect, can be used for treating oil-containing scum with complex components generated in a refinery plant, and has the advantages of small dosage of the dehydrant and high dehydration efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of environmental pollution treatment agents, in particular to an oil-containing scum dehydrating agent. Background Art

[0002] Oily scum refers to the oily sludge produced when oil droplets and solid particles in the water are attached to tiny air bubbles and carried to the water surface after flocculants are added in the flotation section of the wastewater treatment process of petrochemical enterprises. It is mainly composed of negatively charged hydrophilic colloidal particles, with complex composition and difficult to dehydrate. As the quality of crude oil deteriorates, the amount of scum will increase significantly. At present, enterprises generally mix scum with other oil sludge and add flocculants. After mechanical separation and dehydration, the water content is reduced to about 85% and then landfilled as hazardous waste. Due to the serious emulsification of scum, the dehydration effect of the existing process is limited, and crude oil recovery is difficult, which not only increases the burden of hazardous waste treatment for enterprises, but also wastes crude oil resources. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention aims to provide an oily scum dehydrating agent, which is compounded by a demulsifier, a flocculant and a surfactant and has a good dehydrating effect.

[0004] To achieve the above object, the present invention provides the following technical solutions: An oily scum dehydrating agent, comprising, by mass percentage: 40~70% multi-branched demulsifier, 20~40% diquaternary ammonium salt surfactant, 10% flocculant and the rest water; The multi-branched demulsifier is firstly prepared from triethylenetetramine as a reaction initiator and methyl acrylate as a monomer by Michael addition reaction and amidation reaction to obtain a hyperbranched polyamide-amine; then propylene oxide, ethylene oxide and propylene oxide are successively added under alkaline conditions to polymerize to obtain a multi-branched polyether demulsifier; The preparation process of the diquaternary ammonium salt surfactant is as follows: S1. Add rhamnolipid and a catalytic amount of DMAP into a reaction flask, add thionyl chloride dropwise to carry out chlorination reaction, and dissolve the product after the reaction in dichloromethane and place in an ice water bath for standby use; S2, dissolving 6-aminocaproic acid methyl ester hydrochloride and triethylamine in dichloromethane, and then slowly adding them dropwise to step S1, heating to 30°C after the addition, stirring and reacting for 24 hours, adding sodium hydroxide solution, collecting the organic phase, drying and filtering, and the product is ready for use; S3, dissolving the product of step S2 in dichloromethane and placing it in an ice-water bath, slowly adding 3-dimethylaminopropylamine dropwise under nitrogen protection, moving to room temperature after the addition is complete, and continuing to stir the reaction for 24 hours, and distilling under reduced pressure to obtain a viscous liquid; S4, dissolving the viscous liquid in step S3 in ethanol, then adding 3-bromo-propyltrimethylammonium bromide, heating to 90° C. and stirring for 24 h, cooling to room temperature, distilling under reduced pressure to remove the solvent, recrystallizing with a mixed solution of ethanol and acetone, and drying to obtain the product.

[0005] Furthermore, the preparation process of the multi-branched demulsifier is as follows: 1) Add a certain amount of triethylenetetramine to the reaction bottle, add methanol as a solvent and stir to mix evenly, then slowly drop an equal molar amount of methyl acrylate in an ice water bath and under nitrogen protection, heat to 35°C after the addition is complete, stir and react for 48 h; then heat to 60, 80, 100, 120, 140 in stages, react for 2 h respectively, and evacuate during the reaction, and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) Add the hyperbranched polyamide-amine into the reaction kettle, add a catalytic amount of potassium hydroxide, evacuate, raise the temperature to 120°C, and then slowly introduce propylene oxide. When the pressure of the kettle drops to negative pressure and stabilizes, introduce ethylene oxide and propylene oxide into the kettle in sequence, and react at a constant temperature until the pressure of the kettle drops to negative pressure and stabilizes.

[0006] Furthermore, in the step 2), the amounts of raw materials added are: 1 part of hyperbranched polyamide-amine, 10 parts of propylene oxide, 200 parts of ethylene oxide, and 200 parts of propylene oxide.

[0007] Furthermore, the flocculant is polyacrylamide.

[0008] Furthermore, the flocculant is cationic polyacrylamide.

[0009] The composition of the oily scum in the refinery is complex, and it is difficult to achieve an ideal dehydration effect using a single demulsifier or flocculant. The present application prepares a double-headed quaternary ammonium salt surfactant and a multi-branched polyether demulsifier, which are combined with a cationic polyacrylamide flocculant to form a dehydrating agent, which has a high dehydration efficiency when used to treat oily scum. Firstly, cationic polyacrylamide is used as a flocculant to flocculate the sludge in the scum to form loose small flocs for removal; the diquaternary ammonium surfactant is obtained by modifying the biosurfactant rhamnolipid as the starting material. Rhamnolipid is biodegradable and has a certain demulsification effect. Through modification, a double-headed quaternary ammonium salt is grafted on its surface, which has a high solubility and an adsorption bridging effect, further promoting the flocculation effect; the multi-branched demulsifier is based on a hyperbranched polyamide-amine polymer, using the amino groups on its chain as active sites to polymerize to form a PEO-PPO-PEO chain, and multiple branched polyether chains are diffused on the structure of the hyperbranched polymer chain, which is more conducive to contact with the surface of the oil droplet in three-dimensional space. Under the synergistic effect of the diquaternary ammonium surfactant in reducing the strength of the interfacial film, it can also be more quickly dispersed to the oil-water interface, promote the aggregation of oil droplets, improve the demulsification efficiency, and promote oil-water separation.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: the dehydrating agent of the present invention is prepared by mixing a multi-branched demulsifier, a diquaternary ammonium salt surfactant, a flocculant and water in a specific proportion, and has the characteristics of strong demulsification ability and good flocculation effect, and can be used to treat oily scum with complex components produced by refineries, with a small amount of dehydrating agent used and high dehydration efficiency. DETAILED DESCRIPTION

[0011] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] In addition, 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.

[0013] Example: An oily scum dehydrating agent, comprising, by mass percentage: 40~70% multi-branched demulsifier, 20~40% diquaternary ammonium salt surfactant, 10% cationic polyacrylamide flocculant and the balance water; Wherein, the preparation process of the multi-branched demulsifier is as follows: 1) Add a certain amount of triethylenetetramine to the reaction bottle, add methanol as a solvent and stir to mix evenly, then slowly drop an equal molar amount of methyl acrylate in an ice water bath and under nitrogen protection, heat to 35°C after the addition is complete, stir and react for 48 h; then heat to 60, 80, 100, 120, 140 in stages, react for 2 h respectively, and evacuate during the reaction, and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) Add 1 part of hyperbranched polyamide-amine into the reaction kettle, add a catalytic amount of potassium hydroxide, evacuate, raise the temperature to 120°C, and then slowly introduce 10 parts of propylene oxide. When the pressure of the kettle drops to negative pressure and stabilizes, introduce 200 parts of ethylene oxide and 200 parts of propylene oxide into the kettle in sequence, and react at a constant temperature until the pressure of the kettle drops to negative pressure and stabilizes.

[0014] The preparation process of the diquaternary ammonium salt surfactant is as follows: S1. Add rhamnolipid and a catalytic amount of DMAP into a reaction flask, add thionyl chloride dropwise to carry out chlorination reaction, and dissolve the product after the reaction in dichloromethane and place in an ice water bath for standby use; S2, dissolving 6-aminocaproic acid methyl ester hydrochloride and triethylamine in dichloromethane, and then slowly adding them dropwise to step S1, heating to 30°C after the addition, stirring and reacting for 24 hours, adding sodium hydroxide solution, collecting the organic phase, drying and filtering, and the product is ready for use; S3, dissolving the product of step S2 in dichloromethane and placing it in an ice-water bath, slowly adding 3-dimethylaminopropylamine dropwise under nitrogen protection, moving to room temperature after the addition is complete, and continuing to stir the reaction for 24 hours, and distilling under reduced pressure to obtain a viscous liquid; S4, dissolving the viscous liquid in step S3 in ethanol, then adding 3-bromo-propyltrimethylammonium bromide, heating to 90° C. and stirring for 24 h, cooling to room temperature, distilling under reduced pressure to remove the solvent, recrystallizing with a mixed solution of ethanol and acetone, and drying to obtain the product.

[0015] According to the above preparation process, a multi-branched demulsifier and a diquaternary ammonium surfactant were prepared respectively, and then mixed with cationic polyacrylamide and water in a certain proportion to form a dehydrating agent (Examples 1-4), and the dehydrating agent was applied to the scum dehydration treatment.

[0016] For comparison, the present application also uses PEO-PPO-PEO instead of the multi-branched demulsifier to obtain Comparative Example 1, and uses rhamnolipid instead of the diquaternary ammonium salt surfactant to obtain Comparative Example 2.

[0017] This application takes the oil-containing scum of the flotation section of Yangzhou Petrochemical as the research object. After on-site sampling and analysis, the water content of the scum of the flotation section of the enterprise is 97%. The amount of dehydrating agent added is 10mg / L. After stirring and standing for 2h, the water content of the scum after natural sedimentation is calculated. The determination of water content refers to GB / T 260-2016 "Determination of water content of petroleum products by distillation method".

[0018] Table 1 In the table, A:B:C:D are the mass ratios of multi-branched demulsifier: diquaternary ammonium salt surfactant: cationic polyacrylamide flocculant: water. A in Comparative Example 1 is PEO-PPO-PEO, and the rest is the same as in Example 2; B in Comparative Example 2 is rhamnolipid, and the rest is the same as in Example 2; Comparative Example 3 does not add cationic polyacrylamide.

[0019] It can be seen from Table 1 that the dehydration rate of the scum treatment in the present application is more than 60% after the addition amount is only 10 mg / L and the standing time is 2h. By comparing Comparative Examples 1-3, it can be found that the multi-branched demulsifier plays a vital role in the dehydration process, and the diquaternary ammonium salt surfactant and the cationic polyacrylamide flocculant also play a synergistic auxiliary role to a certain extent, which ultimately makes the dehydrating agent more efficient.

[0020] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and shown and described herein.

Claims

1. An oily scum dehydrating agent, characterized in that: Included by mass percentage: 40~70% multi-branched demulsifier, 20~40% diquaternary ammonium salt surfactant, 10% flocculant and the rest water; The multi-branched demulsifier is firstly prepared from triethylenetetramine as a reaction initiator and methyl acrylate as a monomer by Michael addition reaction and amidation reaction to obtain a hyperbranched polyamide-amine; then propylene oxide, ethylene oxide and propylene oxide are successively added under alkaline conditions to polymerize to obtain a multi-branched polyether demulsifier; The preparation process of the diquaternary ammonium salt surfactant is as follows: S1. Add rhamnolipid and a catalytic amount of DMAP into a reaction flask, add thionyl chloride dropwise to carry out chlorination reaction, and dissolve the product after the reaction in dichloromethane and place in an ice water bath for standby use; S2, dissolving 6-aminocaproic acid methyl ester hydrochloride and triethylamine in dichloromethane, and then slowly adding them dropwise to step S1, heating to 30°C after the addition, stirring and reacting for 24 hours, adding sodium hydroxide solution, collecting the organic phase, drying and filtering, and the product is ready for use; S3, dissolving the product of step S2 in dichloromethane and placing it in an ice-water bath, slowly adding 3-dimethylaminopropylamine dropwise under nitrogen protection, moving to room temperature after the addition is complete, and continuing to stir the reaction for 24 hours, and distilling under reduced pressure to obtain a viscous liquid; S4, dissolving the viscous liquid in step S3 in ethanol, then adding 3-bromo-propyltrimethylammonium bromide, heating to 90° C. and stirring for 24 h, cooling to room temperature, distilling under reduced pressure to remove the solvent, recrystallizing with a mixed solution of ethanol and acetone, and drying to obtain the product.

2. The oily scum dehydrating agent according to claim 1, characterized in that: The preparation process of the multi-branched demulsifier is as follows: 1) Add a certain amount of triethylenetetramine to a reaction bottle, add methanol as a solvent and stir to mix evenly, then slowly drop an equal molar amount of methyl acrylate in an ice water bath and under nitrogen protection, heat to 35°C after the dropwise addition is complete, stir and react for 48 hours; then heat to 60, 80, 100, 120, 140 in stages, react for 2 hours respectively, and evacuate during the reaction, and the obtained viscous liquid is the hyperbranched polyamide-amine; 2) Add the hyperbranched polyamide-amine into the reaction kettle, add a catalytic amount of potassium hydroxide, evacuate, raise the temperature to 120°C, and then slowly introduce propylene oxide. When the pressure of the kettle drops to negative pressure and stabilizes, introduce ethylene oxide and propylene oxide into the kettle in sequence, and react at a constant temperature until the pressure of the kettle drops to negative pressure and stabilizes.

3. The oily scum dehydrating agent according to claim 2, characterized in that: In the step 2), the amounts of raw materials added are: 1 part of hyperbranched polyamide-amine, 10 parts of propylene oxide, 200 parts of ethylene oxide, and 200 parts of propylene oxide.

4. The oily scum dehydrating agent according to claim 1, characterized in that: The flocculant is polyacrylamide.

5. The oily scum dehydrating agent according to claim 1, characterized in that: The flocculant is cationic polyacrylamide.

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