Demulsifier for oil-water separation of fermentation liquor and preparation method of demulsifier

Abstract

The invention relates to the technical field of demulsifiers, and particularly provides a demulsifier for oil-water separation of fermentation liquor and a preparation method of the demulsifier. The demulsifying agent disclosed by the invention is prepared from the following components in parts by weight: 50 to 65 parts of fatty diamine polyoxyethylene ether, 20 to 30 parts of fatty amine polyoxyethylene ether, 5 to 15 parts of fatty alcohol polyoxypropylene polyoxyethylene ether and 5 to 10 parts of dispersing agent. The preparation method comprises the following steps: S1, weighing fatty diamine polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty alcohol polyoxyethylene polyoxypropylene ether and a dispersing agent according to a preset proportion; and S2, uniformly mixing the components weighed in the step S1, heating to a preset temperature, and stirring and mixing for 3-4 hours. The demulsifier is good in demulsification performance and convenient to operate and control in the actual application process.

Description

Technical Field

[0001] This invention relates to the field of demulsifier technology, specifically providing a demulsifier for oil-water separation of fermentation broth and its preparation method. Background Technology

[0002] The simplest way to achieve effective separation of the organic and aqueous phases is to use a demulsifier to eliminate the emulsion interface and achieve separation. However, different demulsifiers have different abilities to demulsify the organic phase, and their performance directly affects the separation effect. Taking penicillin as an example, when extracting penicillin from fermentation broth with butyl acetate, because the fermentation broth contains a large amount of positively charged soluble proteins, sugars, mycelia, and other mixtures, an emulsion layer is formed at the interface between the organic and aqueous phases during extraction, affecting the product yield. Therefore, a demulsifier needs to be added during production to remove the emulsion and achieve rapid separation of the two phases.

[0003] To address the separation difficulties caused by emulsification during penicillin extraction, demulsifiers are currently the primary method for two-phase separation, and their performance directly affects penicillin yield. The fermentation oil-water separation demulsifier disclosed in Chinese patent CN1389291A, composed of 50%-80% amide, 20%-50% alkylamine polyoxyethylene ether, and 0%-20% additives, is currently used in domestic penicillin production. This demulsifier has low water and fat solubility, and while it is effective for demulsifying low-fermentation-unit, low-viscosity penicillin fermentation broths, its effectiveness is poor when used in high-fermentation-unit, high-viscosity penicillin fermentation broths, which have become more common in recent years. It easily leads to problems such as gelation and excessive foaming, severely impacting production. Summary of the Invention

[0004] To overcome the above-mentioned defects, the present invention provides a demulsifier for oil-water separation of fermentation broth and its preparation method. The demulsifier has good demulsification performance and is easy to operate and control in practical applications.

[0005] In a first aspect, the present invention provides a demulsifier for oil-water separation of fermentation broth, comprising, by weight: 50-65 parts of fatty diamine polyoxyethylene ether, 20-30 parts of fatty amine polyoxyethylene ether, 5-15 parts of fatty alcohol polyoxypropylene polyoxyethylene ether, and 5-10 parts of dispersant.

[0006] Furthermore, the dispersant is a bisquaternary ammonium salt.

[0007] Furthermore, the bisquaternary ammonium salt is a dodecylamine polyoxyethylene ether bisquaternary ammonium salt.

[0008] Furthermore, the dispersant further includes: polyoxyethylene ether and polyacrylamide; wherein the mass ratio of bisquaternary ammonium salt, polyoxyethylene ether and polyacrylamide is (55-65):(25-35):(8-12).

[0009] In a second aspect, the present invention provides a method for preparing a demulsifier, comprising: S1, Weigh out fatty diamine polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty alcohol polyoxyethylene polyoxypropylene ether and dispersant according to the preset ratio; S2, mix the components weighed in step S1 evenly, heat to the preset temperature, and stir for 3-4 hours.

[0010] Furthermore, in step S2, the preset temperature is 70-80℃.

[0011] Furthermore, the aliphatic diamine polyoxyethylene ether is prepared by alkaline catalysis of aliphatic diamine and ethylene oxide.

[0012] Furthermore, the fatty amine polyoxyethylene ether is prepared by alkaline catalysis of fatty amine and ethylene oxide.

[0013] Furthermore, the fatty alcohol polyoxypropylene polyoxyethylene ether is prepared by alkaline catalysis of fatty alcohol with ethylene oxide and propylene oxide.

[0014] The above-described technical solutions of the present invention have at least one or more of the following beneficial effects: In implementing the technical solution of this invention, the demulsifier exhibits excellent demulsification performance and is also simple and easy to operate. With its superior demulsification and operational performance, the demulsifier of this invention can effectively solve the problems currently faced in penicillin production, such as incomplete demulsification and low production efficiency due to complex operations.

[0015] The demulsifier of this invention is soluble in butyl acetate and can neutralize two soluble proteins with positive and negative charges, making the interface easier to separate, resulting in good demulsification effect and low dosage.

[0016] This invention is applicable to demulsification of penicillin fermentation broth with high fermentation unit and high viscosity. Attached Figure Description

[0017] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Furthermore, similar numbers in the drawings are used to denote similar components, wherein: Figure 1 This is a schematic flowchart of the main steps in the preparation method of a demulsifier according to an embodiment of the present invention. Detailed Implementation

[0018] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] This invention provides a demulsifier for oil-water separation in fermentation broth. This demulsifier plays a crucial role in the oil-water separation process, effectively achieving oil-water separation. The main components of this demulsifier include fatty diamine polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty alcohol polyoxypropylene polyoxyethylene ether, and a dispersant. These components work synergistically to achieve a good demulsification effect.

[0020] To demonstrate the proportions of each component, parts by weight are used for measurement. Specifically, in the overall composition of the demulsifier, fatty diamine polyoxyethylene ether comprises 50-65 parts. This content ensures that it plays a major role in the demulsification process, influencing the interfacial properties between oil and water droplets in the fermentation broth. Fatty amine polyoxyethylene ether comprises 20-30 parts, which works synergistically with other components to further optimize the demulsification effect; fatty alcohol polyoxypropylene polyoxyethylene ether comprises 5-15 parts, whose unique molecular structure helps to regulate the performance of the demulsifier; and dispersant comprises 5-10 parts, which enables other components to be better dispersed in the system, ensuring the overall stability and uniformity of the demulsifier's performance.

[0021] In one embodiment, the dispersant is a bisquaternary ammonium salt.

[0022] In one embodiment, the bisquaternary ammonium salt is dodecylamine polyoxyethylene ether bisquaternary ammonium salt.

[0023] In one embodiment, the dispersant further includes: polyoxyethylene ether and polyacrylamide; wherein, The mass ratio of bisquaternary ammonium salt, polyoxyethylene ether and polyacrylamide is (55-65): (25-35): (8-12).

[0024] In the dispersant, the quaternary ammonium salt is the main force for charge neutralization, quickly neutralizing negatively charged proteins and mycelial fragments in the fermentation broth and disrupting the electrostatic stability mechanism of the emulsion layer.

[0025] Polyoxyethylene ethers are used as interfacial penetrants and wetting agents. They reduce interfacial tension, help demulsifiers effectively penetrate into the interior of high-viscosity emulsions, and improve the clarity of oil-water phase separation.

[0026] Polyacrylamide is used as a steric hindrance and flocculant aid. By bridging long molecular chains and providing steric repulsion, it prevents the re-aggregation of demulsified particles and promotes the flocculation and sedimentation of fine suspended matter, thereby achieving a cleaner two-phase interface.

[0027] This invention uses fatty diamine polyoxyethylene ether as the base material for demulsifier, and then combines it with fatty amine polyoxyethylene ether, fatty alcohol polyoxypropylene polyoxyethylene ether and dispersant. The four components work synergistically to overcome the shortcomings of demulsifiers composed of oleamide and alkylamine polyoxyethylene ether.

[0028] To further improve the effect of the demulsifier, especially for demulsifying high-viscosity fermentation broths, the demulsifier of the present invention further includes: an synergist in parts by weight of 2-10.

[0029] In one embodiment, the synergist is cationic polyacrylamide, which functions as a flocculation and sedimentation agent and a solid phase removal agent. In high-viscosity fermentation broths, solid particles are an important "stabilizing framework" for the emulsion layer. Cationic polyacrylamide removes these particles from the interface region through flocculation, directly dismantling the physical support structure of the emulsion layer and making the oil-water interface film fragile and easily broken.

[0030] The resulting flocs settle to the bottom of the aqueous phase, significantly reducing the content of suspended solids and impurities in the oil phase (butyl acetate), thereby obtaining an extremely clear organic phase. This not only improves the quality of penicillin products (low residue) but also reduces the burden on subsequent refining processes.

[0031] The rapid flocculation effect of cationic polyacrylamide clears the way for the main demulsifier, which is mainly composed of fatty diamine polyoxyethylene ether, allowing it to focus more on breaking down the remaining emulsion stabilized by surfactants, thus improving the efficiency of the main agent.

[0032] To further strengthen the interface and prevent reemulsification, the synergist also includes EO-PO-EO triblock polyether. EO-PO-EO triblock polyether is a fully polyether-type polymer, specifically a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer. Its symmetrical triblock structure of "hydrophilic (EO)-hydrophobic (PO)-hydrophilic (EO)" exhibits extremely strong interfacial directional adsorption capabilities. The hydrophobic PO segments tend to anchor in the oil phase or the hydrophobic region of the interface, while the hydrophilic EO segments on both sides extend into the aqueous phase, forming a robust "anchor-chain" structure. It can compete for interfacial sites with naturally occurring, highly interfacially active substances such as proteins and phospholipids in the fermentation broth. Due to its more regular molecular structure and higher adsorption energy, it can effectively replace or displace the original emulsifier, thereby weakening the stubborn interfacial film with high viscoelasticity formed by proteins, etc. When oil droplets coalesce due to the action of demulsifiers, this thick hydration layer effectively prevents the separated oil or water droplets from approaching, colliding, and emulsifying again under flow or shear, ensuring the irreversibility of separation and the long-term clarity and stability of the interface.

[0033] In one embodiment, the synergist is cationic polyacrylamide and EO-PO-EO triblock polyether in a mass ratio of 2.5:1.

[0034] This invention also provides a method for preparing the above-mentioned demulsifier, referring to... Figure 1 ,include: S1, Weigh out fatty diamine polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty alcohol polyoxyethylene polyoxypropylene ether and dispersant according to the preset ratio; S2, mix the components weighed in step S1 evenly, heat to the preset temperature, and stir for 3-4 hours.

[0035] In one embodiment, in step S2, the preset temperature is 70-80°C.

[0036] The following describes the preparation process of the main components of the demulsifier. First, the preparation process of aliphatic diamine polyoxyethylene ether will be described. In one embodiment, the aliphatic diamine polyoxyethylene ether is prepared by alkaline catalysis of aliphatic diamine and ethylene oxide. The alkaline catalysis process involves using an alkaline catalyst for the catalytic reaction. Potassium hydroxide can be selected as the alkaline catalyst.

[0037] In one embodiment, the mass ratio of aliphatic diamine to ethylene oxide is 1:(0.55-1.38).

[0038] In one embodiment, the basic catalyst accounts for 0.3% - 0.5% of the mass fraction of the aliphatic diamine.

[0039] In one embodiment, the preparation process of aliphatic diamine polyoxyethylene ether includes: a. Mix tallow diamine with an alkaline catalyst until homogeneous to obtain the first mixture; b. Heat the first mixture to 150-160℃, then add ethylene oxide to carry out a catalytic reaction, and the product is obtained after the reaction.

[0040] Fatty diamine polyoxyethylene ether is an amine ether compound produced by the alkaline-catalyzed reaction of tallow diamine and ethylene oxide at 150-160℃. The general reaction formula is: R-NHCH2CH2CH2NH2+(X+Y)(C2H4O)→RN(C2H4O) X CH2CH2CH2N(C2H4O)Y, where X+Y is 3-11 and R is C 12 -C 18 Alkyl groups.

[0041] The preparation process of fatty amine polyoxyethylene ether will be described below. In one embodiment, the fatty amine polyoxyethylene ether is prepared by alkaline catalysis of a fatty amine and ethylene oxide. The alkaline catalysis process involves using an alkaline catalyst for the catalytic reaction. Potassium hydroxide can be selected as the alkaline catalyst.

[0042] In one embodiment, the mass ratio of fatty amine to ethylene oxide is 1:(0.3-2).

[0043] In one embodiment, the alkaline catalyst accounts for 0.3% - 0.5% of the mass fraction of the fatty amine.

[0044] In one embodiment, the preparation process of fatty amine polyoxyethylene ether includes: c. Mix the fatty amine with the alkaline catalyst until homogeneous to obtain a second mixture; d. The second mixture is heated to 150-160℃, and then ethylene oxide is added to carry out a catalytic reaction, and the product is obtained after the reaction.

[0045] Fatty amine polyoxyethylene ether is an amine ether produced by the alkalization reaction of fatty amines with ethylene oxide. The general reaction formula is: RNH2+N(C2H4O)→RN(C2H4O)nH where R is a C12-C18 alkyl group and n is 2-10.

[0046] The preparation process of fatty alcohol polyoxypropylene polyoxyethylene ether is described below. In one embodiment, the fatty alcohol polyoxypropylene polyoxyethylene ether is prepared by alkaline catalysis of fatty alcohol with ethylene oxide and propylene oxide. The alkaline catalysis process involves using an alkaline catalyst for the catalytic reaction. Potassium hydroxide can be selected as the alkaline catalyst.

[0047] In one embodiment, the mass ratio of fatty alcohol to ethylene oxide and propylene oxide is 1:2.4:1.6.

[0048] In one embodiment, the alkaline catalyst accounts for 0.4%-0.6% of the mass fraction of the fatty alcohol.

[0049] In one embodiment, the preparation process of fatty alcohol polyoxypropylene polyoxyethylene ether includes: e. Mix octadecyl alcohol with an alkaline catalyst until homogeneous to obtain a third mixture; f. The third mixture is heated to 120-130℃, and then ethylene oxide and propylene oxide are added for catalytic reaction. The product is obtained after the reaction.

[0050] Fatty alcohol polyoxypropylene polyoxyethylene ether is a polyether compound formed by the alkaline-catalyzed reaction of fatty alcohols with propylene oxide and ethylene oxide. The general reaction formula is: C n H 2n+1 OH + X(C3H6O) + Y(C2H4O) → C n H 2n+1 (C3H6O) X (C2H4O) Y H, where R is C 12 -C 18 Alkyl groups, where X is 10-11 and Y is 9-10.

[0051] The following examples illustrate the effect of the demulsifier of the present invention. Example 1

[0052] Take 320 kg of aliphatic diamine, heat it to 155°C under the action of 1.28 kg of alkaline catalyst potassium hydroxide, and pass in 176 kg of ethylene oxide to obtain aliphatic diamine polyoxyethylene (4) ether.

[0053] Take 268 kg of octadecylamine, heat it to 153°C under the action of 1.07 kg of alkaline catalyst potassium hydroxide, and pass 132 kg of ethylene oxide through it to obtain octadecylamine polyoxyethylene (3) ether.

[0054] Take 270 kg of octadecyl alcohol, heat it to 128°C under the action of 1.35 kg of alkaline catalyst potassium hydroxide, and pass in 638 kg of propylene oxide and 440 kg of ethylene oxide to obtain octadecyl alcohol polyoxypropylene (11) polyoxyethylene (10) ether.

[0055] S1, weigh each component according to the mass percentage: 55% fatty diamine polyoxyethylene (3) ether, 25% octadecylamine polyoxyethylene (3) ether, 15% octadecyl alcohol polyoxypropylene (11) ether polyoxyethylene (10) ether, and 5% dodecylamine polyoxyethylene ether bisquaternary ammonium salt. S2. Mix all the components from step S1 evenly, heat to 80°C, and stir for 3 hours to obtain the demulsifier. Example 2

[0056] Take 320 kg of aliphatic diamine, heat it to 160°C under the action of 0.96 kg of alkaline catalyst potassium hydroxide, and pass in 264 kg of ethylene oxide to obtain aliphatic diamine polyoxyethylene (6) ether.

[0057] Take 142 kg of dodecylamine, heat it to 151°C under the action of 0.71 kg of alkaline catalyst potassium hydroxide, and pass 132 kg of ethylene oxide through it to obtain dodecylamine polyoxyethylene (3) ether.

[0058] Take 270 kg of octadecyl alcohol, heat it to 130°C with 1.62 kg of alkaline catalyst potassium hydroxide, and pass in 638 kg of propylene oxide and 440 kg of ethylene oxide to obtain octadecyl alcohol polyoxypropylene (11) polyoxyethylene (10) ether.

[0059] S1, by mass percentage, comprises 55% fatty diamine polyoxyethylene (6) ether, 25% dodecylamine polyoxyethylene (3) ether, 15% octadecyl alcohol polyoxypropylene (11) ether polyoxyethylene (10) ether and 5% dodecylamine polyoxyethylene ether bisquaternary ammonium salt.

[0060] S2. Mix all the components from step S1 evenly, heat to 75°C, and stir for 3.5 hours to obtain the demulsifier. Example 3

[0061] Take 320 kg of aliphatic diamine, heat it to 150°C under the action of 1.6 kg of alkaline catalyst potassium hydroxide, and pass in 308 kg of ethylene oxide to obtain aliphatic diamine polyoxyethylene (7) ether.

[0062] Take 142 kg of dodecylamine and heat it to 160°C under the action of 0.554 kg of alkaline catalyst potassium hydroxide, and pass 440 kg of ethylene oxide through it to obtain dodecylamine polyoxyethylene (10) ether.

[0063] Take 270 kg of octadecyl alcohol, heat it to 128°C under the action of 1.08 kg of alkaline catalyst potassium hydroxide, and pass in 638 kg of propylene oxide and 440 kg of ethylene oxide to obtain octadecyl alcohol polyoxypropylene (11) polyoxyethylene (10) ether.

[0064] S1, by mass percentage, comprises 55% fatty diamine polyoxyethylene (7) ether, 25% dodecylamine polyoxyethylene (10) ether, 15% octadecyl alcohol polyoxypropylene (11) ether polyoxyethylene (10) ether and 5% dodecylamine polyoxyethylene ether bisquaternary ammonium salt.

[0065] S2. Mix all the components from step S1 evenly, heat to 70°C, and stir for 4 hours to obtain the demulsifier. Example 4

[0066] Take 320 kg of aliphatic diamine, heat it to 159°C under the action of 1.28 kg of alkaline catalyst potassium hydroxide, and pass in 440 kg of ethylene oxide to obtain aliphatic diamine polyoxyethylene (10) ether.

[0067] Take 268 kg of octadecylamine, heat it to 150°C under the action of 0.804 kg of alkaline catalyst potassium hydroxide, and pass 440 kg of ethylene oxide through it to obtain octadecylamine polyoxyethylene (10) ether.

[0068] Take 270 kg of octadecyl alcohol, heat it to 120°C under the action of 1.566 kg of alkaline catalyst potassium hydroxide, and pass in 638 kg of propylene oxide and 440 kg of ethylene oxide to obtain octadecyl alcohol polyoxypropylene (11) polyoxyethylene (10) ether.

[0069] S1, by weight percentage, consists of 55% fatty diamine polyoxyethylene (10) ether, 25% octadecylamine polyoxyethylene (10) ether, 15% octadecyl alcohol polyoxypropylene (11) ether polyoxyethylene (10) ether and 5% dodecylamine polyoxyethylene ether bisquaternary ammonium salt.

[0070] S2. Mix all the components from step S1 evenly, heat to 72°C, and stir for 3 hours to obtain the demulsifier. Example 5

[0071] The only difference between this embodiment and Example 1 is that the dispersant in this embodiment further includes polyoxyethylene ether and polyacrylamide. The mass ratio of the bisquaternary ammonium salt, polyoxyethylene ether, and polyacrylamide is 60:30:10. During the preparation process, in step S2, all components of the dispersant are added together, mixed evenly with the other components, and then heated. Example 6

[0072] The only difference between this embodiment and Example 5 is that the mass ratio of bisquaternary ammonium salt, polyoxyethylene ether, and polyacrylamide in the dispersant of this embodiment is 55:35:8. Example 7

[0073] The only difference between this embodiment and Example 5 is that the mass ratio of bisquaternary ammonium salt, polyoxyethylene ether, and polyacrylamide in the dispersant of this embodiment is 65:25:12. Example 8

[0074] The difference between this embodiment and Embodiment 1 is that this embodiment further includes 8 parts by weight of a synergist. The synergist is cationic polyacrylamide and EO-PO-EO triblock polyether, with a mass ratio of 2.5:1. The synergist is added in step S2, and after being mixed evenly with the other components, it is heated.

[0075] Comparative Example 1 The preparation process of the demulsifier in this comparative example includes: (1) Add 263 kg of oleic acid (octadecenoic acid), 230 kg of polyethylene polyamine, and 220 kg of xylene to a reaction vessel, heat and stir to 120-170℃, and carry out acylation and dehydration to remove all water. Remove all xylene by vacuum distillation to obtain the product oleyl polyethylene polyamine.

[0076] (2) 269 kg of octadecylamine was heated to 170-190°C and 396 kg of ethylene oxide was introduced to obtain octadecylamine polyoxyethylene (9) ether.

[0077] (3) Mix 210 kg of oleoyl polyethylene amine obtained in step (1) with 90 kg of octadecylamine polyoxyethylene (9) ether obtained in step (2), heat to 70-90°C, stir and mix for 4 hours, and filter while hot to obtain a transparent brown viscous and uniform demulsifier.

[0078] This invention tests the demulsifiers used in Examples 1-5, Example 8, and Comparative Example 1 to assess their demulsification effect on penicillin fermentation broth. During the tests, the penicillin filtrate concentration was 123,000 u / ml, and the demulsifier dosage was 1200 mg / kg. The test results are shown in Tables 1-2.

[0079] Table 1. Static Experiment of Demulsification Effect

[0080] The present invention also conducted a comparative observation experiment on the demulsifiers of Example 1 and Comparative Example 1. The specific process was as follows: 50 ml of penicillin filtrate and 20 ml of butyl acetate were added to 1-2 ml of demulsifier (6% aqueous solution) (600-1200 mg / Kg). Sulfuric acid (1.2%) was added to adjust the pH to 1.9-2.1. The mixture was stirred at 300 rpm for 2 minutes. 10 ml of the solution was placed in a centrifuge tube and centrifuged at 5000 rpm for 3-5 minutes. The mixture was then observed. The remaining solution was placed in a graduated cylinder and allowed to stand for observation to observe the separation of the oil and water phases.

[0081] Table 2. Observation of demulsifier comparison

[0082] Analysis of the data presented in Tables 1 and 2 shows that the demulsifier of this invention exhibits excellent demulsification performance, significantly outperforming similar products. Furthermore, it boasts a simple and easy-to-use operation process. With its superior demulsification and operational performance, this demulsifier effectively addresses current problems in penicillin production, such as incomplete demulsification and low production efficiency due to complex operations. Therefore, this demulsifier, with its strong demulsification ability, low dosage, and environmentally friendly all-fermentation broth oil-water demulsifier, possesses significant potential for widespread application.

[0083] The demulsifier of this invention is soluble in butyl acetate and can neutralize two soluble proteins with positive and negative charges, making the interface easier to separate. It has a good demulsification effect and requires only 600-1200 mg / Kg.

[0084] This invention is suitable for demulsifying penicillin fermentation broths with high fermentation unit and high viscosity. It not only achieves excellent demulsification but also maintains a stable penicillin yield of over 95%, with virtually no residue, thus improving the quality of the finished penicillin product and reducing production costs. It should be noted that while this demulsifier is particularly suitable for, but not limited to, demulsification of fermentation broths used for extraction and separation, such as for penicillin.

[0085] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effects of the present invention, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these variations are all within the scope of protection of the present invention.

[0086] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A demulsifier for oil-water separation of fermentation broth, characterized in that, It comprises, by weight: 50-65 parts of fatty diamine polyoxyethylene ether, 20-30 parts of fatty amine polyoxyethylene ether, 5-15 parts of fatty alcohol polyoxypropylene polyoxyethylene ether, and 5-10 parts of dispersant.

2. The demulsifier according to claim 1, characterized in that, The dispersant is a bisquaternary ammonium salt.

3. The demulsifier according to claim 2, characterized in that, The quaternary ammonium salt is dodecylamine polyoxyethylene ether quaternary ammonium salt.

4. The demulsifier according to claim 2 or 3, characterized in that, The dispersant further includes: polyoxyethylene ether and polyacrylamide; wherein the mass ratio of bisquaternary ammonium salt, polyoxyethylene ether and polyacrylamide is (55-65):(25-35):(8-12).

5. A method for preparing the demulsifier according to any one of claims 1-4, characterized in that, include: S1, Weigh out fatty diamine polyoxyethylene ether, fatty amine polyoxyethylene ether, fatty alcohol polyoxyethylene polyoxypropylene ether and dispersant according to the preset ratio; S2, mix the components weighed in step S1 evenly, heat to the preset temperature, and stir for 3-4 hours.

6. The preparation method according to claim 1, characterized in that, In step S2, the preset temperature is 70-80℃.

7. The method according to claim 5, characterized in that, The aliphatic diamine polyoxyethylene ether is prepared by alkaline catalysis of aliphatic diamine and ethylene oxide.

8. The method according to claim 5, characterized in that, The fatty amine polyoxyethylene ether is prepared by alkaline catalysis of fatty amine and ethylene oxide.

9. The method according to claim 5, characterized in that, The fatty alcohol polyoxypropylene polyoxyethylene ether is prepared by alkaline catalysis of fatty alcohol with ethylene oxide and propylene oxide.

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