Demulsifier for raw gas quenching oil emulsion as well as preparation method and application of demulsifier

Abstract

The invention belongs to the technical field of coal chemical industry oil product treatment, and discloses a demulsifying agent for raw gas quenching oil emulsion and a preparation method and application thereof.The demulsifying agent is a star-like three-dimensional structure nonionic polyether demulsifying agent comprising 2-4 polyether branched chains, and the preparation method comprises the following steps that polyether is dissolved in an organic solvent; performing esterification reaction with acrylic acid in an inert atmosphere in the presence of a catalyst to obtain polyether acrylate; and carrying out Michael addition reaction with a polyamine compound in an alcohol solvent to obtain the demulsifier. The preparation method of the demulsifier provided by the invention is simple, green and environment-friendly, and the demulsifier has excellent demulsification performance on stable water-in-oil emulsions such as raw coke oven gas quenching oil and the like, and can realize rapid and efficient oil-water separation.

Description

Technical Field

[0001] This invention relates to the field of coal chemical oil processing technology, specifically to a demulsifier for quenching oil emulsions of raw coal gas, its preparation method, and its application. Background Technology

[0002] Raw coal gas, generated during coal gasification, coking, and coal chemical production processes, typically requires quenching for cooling and purification. During quenching, the raw coal gas comes into full contact with the quenching medium and cools rapidly, easily forming a complex oil-water mixture, known as raw coal gas quenching oil. This type of quenching oil usually contains asphaltenes, resins, and various polar organic components, which readily form stable oil-water emulsions under external shear forces, posing challenges to subsequent oil-water separation and resource recovery.

[0003] Currently, the main methods for treating raw coal gas quench oil emulsions include gravity sedimentation, heating separation, centrifugal separation, and chemical demulsification. Among these, gravity sedimentation and heating separation have relatively low efficiency and high energy consumption; centrifugal separation equipment has high investment and operating costs. In contrast, using chemical demulsifiers for demulsification treatment has advantages such as simple operation and high treatment efficiency, and has become a commonly used technical means in the demulsification treatment of raw coal gas quench oil.

[0004] Among various chemical demulsification strategies, nonionic polyether demulsifiers, with their amphiphilic molecular structure that combines hydrophilic and hydrophobic segments, can rapidly accumulate at the interface and regulate interfacial tension and membrane mechanical properties. Under certain conditions, these demulsifiers can achieve oil-water separation. However, in highly stable emulsion systems such as raw coal gas quench oil, traditional linear polyethers still generally suffer from problems such as limited demulsification efficiency, large dosage, or insufficient adaptability. Furthermore, some preparation methods are complex and not conducive to practical applications.

[0005] Therefore, it is necessary to develop a high-efficiency demulsifier that is easy to prepare, has a controllable structure, and is suitable for the quenching oil system of raw coal gas, so as to improve the oil-water separation efficiency and meet the actual needs of coal chemical production processes. Summary of the Invention

[0006] In view of this, the present invention provides a demulsifier for raw coal gas quench oil emulsion, its preparation method and application, which solves the problems of limited demulsification efficiency and insufficient adaptability of existing demulsifiers in raw coal gas quench oil emulsion, and achieves efficient demulsification treatment of raw coal gas quench oil emulsion.

[0007] The technical solution of the present invention is as follows: The first aspect of this invention provides a demulsifier for quenching oil emulsions of raw coal gas. The demulsifier is a nonionic polyether demulsifier with a quasar-shaped three-dimensional structure comprising 2-4 polyether branches. The demulsifier is prepared by Michael addition reaction of polyether with a polyamine compound after acrylate esterification. The general chemical formula of the demulsifier is as follows: , where m is between 15 and 48, n is between 5 and 8, and m and n are positive integers.

[0008] Preferably, the polyamine compound is one or more of ethylenediamine, diethylenetriamine, and triethylenetetramine.

[0009] Preferably, the polyether is a copolymer obtained by ring-opening polymerization of ethylene oxide and propylene oxide using a polyol as an initiator. The molar ratio of ethylene oxide to propylene oxide is (4-6):1. The polyol is one or more of propylene glycol, ethylene glycol, or glycerol.

[0010] Preferably, the number-average molecular weight of the polyether is 2000-8000.

[0011] A second aspect of the present invention provides a method for preparing a demulsifier for quenching oil emulsions of raw coal gas, comprising the following steps: Step S1: Dissolve the polyether in an organic solvent and, in the presence of an inert atmosphere and a catalyst, react it with acrylic acid to obtain polyether acrylate. Step S2: Dissolve the polyether acrylate obtained in step S1 in an alcohol solvent, and carry out a Michael addition reaction with a polyamine compound under an inert atmosphere. After the reaction is completed, remove the solvent and dry to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier.

[0012] Preferably, in step S1, the catalyst is an acidic catalyst selected from p-toluenesulfonic acid, methanesulfonic acid, and benzoic acid monohydrate, and more preferably p-toluenesulfonic acid; the organic solvent is selected from xylene, toluene, and cyclohexane.

[0013] Preferably, the molar ratio of the polyether to acrylic acid is 1:(2.5-4), more preferably 1:(3.0-3.5), and the amount of catalyst added is 0.2%-0.3% of the molar amount of the polyether.

[0014] Preferably, in step S1, the esterification reaction temperature is 120-140 °C and the reaction time is 4-6 h.

[0015] Preferably, in step S2, the alcohol solvent is anhydrous methanol or anhydrous ethanol, and the molar ratio of the polyether acrylate to the polyamine compound is 1:(2.4-2.6).

[0016] Preferably, in step S2, the Michael addition reaction is carried out at 20-30 °C for 12-36 h, more preferably 20-28 h.

[0017] A second aspect of the present invention provides the application of the above-mentioned demulsifier in demulsification treatment.

[0018] Preferably, the demulsifier is used for demulsification treatment of raw coal gas quench oil emulsion.

[0019] Preferably, the amount of demulsifier added to the raw coal gas quench oil emulsion is 100-1000 mg / L.

[0020] Preferably, the demulsifier is also suitable for demulsifying other coal chemical oil emulsions containing asphaltenes and resins.

[0021] In the quasar-shaped three-dimensional nonionic polyether demulsifier of this invention, the formation of the quasar structure originates from the Michael addition reaction between polyether acrylate and polyamine compounds. First, the polyether molecule is acrylated at its ends, introducing acrylate groups containing α,β-unsaturated double bonds, giving it active sites for nucleophilic addition reactions. Subsequently, the amino groups in the polyamine compound act as nucleophiles, attacking the carbon-carbon double bonds in the acrylate groups, forming a stable β-amino ester structure through a Michael addition reaction. Since polyamine molecules typically contain two or more amino functional groups, each amino group can undergo addition reactions with different polyether acrylate molecules, thereby linking multiple polyether segments together through the polyamine molecule. With the polyamine as the core and the polyether chains as the arms, a quasar-shaped three-dimensional structure with 2-4 polyether branches is formed. This structure allows the molecule to possess both strong hydrophilic and hydrophobic segments, enabling multi-point adsorption at the oil-water interface, thereby enhancing interfacial disturbance and improving demulsification efficiency.

[0022] The advantages and beneficial effects of this invention are: (1) The demulsifier provided by the present invention has a unique quasar-shaped three-dimensional structure. Its multi-branched topology can provide multi-point adsorption at the oil-water interface. Compared with traditional linear structure demulsifiers, it can more effectively destroy the stable interfacial film structure formed by asphaltenes and resins in the raw coal gas quenching oil, thereby improving the demulsification efficiency.

[0023] (2) The molar ratio of ethylene oxide to propylene oxide in the polyether segment of the demulsifier molecule of the present invention is controlled at (4-6):1. While ensuring good water solubility of the demulsifier, it also imparts suitable hydrophobicity, so that the demulsifier can be anchored at the oil-water interface, effectively reducing the oil-water interfacial tension, promoting oil droplet coalescence, and accelerating the oil-water separation process.

[0024] (3) The demulsifier preparation method of the present invention is simple, the reaction conditions are mild, and the raw materials are readily available. The obtained demulsifier is non-ionic, has strong adaptability to the salinity and water quality of the system, and is suitable for efficient demulsification of oil emulsions such as raw coal gas quench oil with complex composition and high stability. Attached Figure Description

[0025] Figure 1 This is the infrared spectrum of the quasar-shaped three-dimensional nonionic polyether demulsifier in Example 1 of this invention.

[0026] Figure 2 This is the thermogravimetric analysis (TGA) of the quasar-shaped three-dimensional nonionic polyether demulsifier in Example 1 of this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0028] This invention provides a method for preparing a demulsifier for quench oil emulsion of raw coal gas, the preparation method comprising the following steps: Step 1: Polyether and acrylic acid are subjected to esterification reaction to synthesize polyether acrylate; Step 2: The polyether acrylate is reacted with a polyamine compound via a Michael addition reaction to obtain a nonionic polyether demulsifier with a quasar-shaped three-dimensional structure having 2-4 branches.

[0029] According to the present invention, the esterification reaction of polyether with acrylic acid in step 1 to synthesize polyether acrylate (PA) includes the following steps: (a) Add polyether and xylene to a three-necked round-bottom flask equipped with a reflux condenser and stir until fully dissolved.

[0030] (b) Acrylic acid was slowly added through a dropping funnel under continuous nitrogen protection. After the addition was complete, p-toluenesulfonic acid was added as a catalyst, and the reaction was carried out under magnetic stirring.

[0031] (c) The reaction solution was removed by rotary evaporation under reduced pressure. The crude product was purified by three cycles of dissolution and precipitation in deionized water to finally obtain polyether acrylate.

[0032] In this invention, the polyether in step (a) is preferably a block or random copolymer obtained by polymerizing ethylene oxide (EO) and propylene oxide (PO) using a polyol as an initiator. The molar ratio of EO to PO is preferably (4-6):1, such as 4:1, 5:1, 6:1, etc., but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The number-average molecular weight of the polyether can be 2000-8000, preferably 4000-6000, such as 4000, 5000, or 6000, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The polyol is propylene glycol, ethylene glycol, or glycerol.

[0033] In this invention, the molar ratio of polyether to acrylic acid in step (a) is preferably 1:(3.0-3.5), such as 1:3 or 1:3.5, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The amount of catalyst added is preferably 0.2%-0.3% of the molar amount of polyether, such as 0.2%, 0.25% or 0.3%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0034] In this invention, the organic solvent in step (b) is preferably xylene, toluene, etc. The catalyst is an acidic catalyst, preferably p-toluenesulfonic acid. The stirring speed is 200-500 r / min, such as 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, or 500 r / min, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 300-400 r / min.

[0035] In this invention, the reaction in step (b) is carried out under the protection of an inert gas (such as nitrogen), and the reaction temperature is preferably 120-140 ℃, such as 120 ℃, 125 ℃, 130 ℃, 135 ℃ or 140 ℃, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable; the reaction time is preferably 4-6 h, such as 4 h, 4.5 h, 5 h, 5.5 h or 6 h, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0036] According to the present invention, step 2 involves a Michael addition reaction between polyether acrylate and a polyamine compound to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier, comprising the following steps: (d) Under nitrogen protection, polyether acrylate is dissolved in anhydrous methanol.

[0037] (e) Add ethylenediamine dropwise and react for a period of time with continuous stirring to allow the Michael addition reaction to occur fully.

[0038] (f) The solvent was removed by rotary evaporation under reduced pressure, and the resulting product was dried under vacuum. The final product was a quasar-shaped three-dimensional nonionic polyether demulsifier (SSP) with 2-4 branches.

[0039] In this invention, the alcohol solvent in step (d) is preferably anhydrous methanol.

[0040] In this invention, the polyamine compound in step (e) is preferably ethylenediamine. The molar ratio of the polyether acrylate to ethylenediamine is preferably 1:(2.4-2.6), such as 1:2.4, 1:2.5, or 1:2.6, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0041] In this invention, the Michael addition reaction temperature in step (e) is preferably 20-30 °C, such as 20 °C, 25 °C or 30 °C, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The reaction time is relatively long, preferably 20-28 h, such as 20 h, 22 h, 24 h, 26 h or 28 h, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0042] In this invention, the vacuum drying temperature in step (f) is preferably 70-90℃, such as 70℃, 75℃, 80℃, 85℃ or 90℃, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable; the vacuum drying time is 10-16h, such as 10h, 12h, 14h or 16h, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0043] As a preferred technical solution, the preparation method of the demulsifier of the present invention includes the following steps: (a) Add 18 g of polyether and 20 mL of xylene to a three-necked round-bottom flask equipped with a reflux condenser, and stir until fully dissolved.

[0044] (b) Under continuous nitrogen protection, 1 g of acrylic acid was slowly added through a dropping funnel. After the addition was complete, 0.001 g of p-toluenesulfonic acid was added as a catalyst. The reaction system was stirred at 300 r / min in a nitrogen atmosphere at 130 °C for 5 h.

[0045] (c) The reaction solution was rotary evaporated at 70 °C under reduced pressure to remove xylene. The crude product was purified by three cycles of dissolution-precipitation in deionized water to finally obtain polyether acrylate (PA).

[0046] (d) Under nitrogen protection, 10 g of polyether acrylate (PA) was dissolved in 50 mL of anhydrous methanol.

[0047] (e) Add 0.02 g of ethylenediamine dropwise and react with continuous stirring for 24 h to allow the Michael addition reaction to fully occur.

[0048] (f) The solvent was removed by rotary evaporation at 40 °C under reduced pressure, and the resulting product was dried under vacuum at 80 °C for 12 h. Finally, a quasar-shaped three-dimensional nonionic polyether demulsifier (SSP) with four branches was obtained.

[0049] The demulsifier preparation method of the present invention is simple, the reaction conditions are mild, and the resulting demulsifier is a non-ionic demulsifier with strong adaptability to system salinity and water quality. It is suitable for demulsification treatment of complex oil emulsions such as raw coal gas quench oil.

[0050] The present invention will be further illustrated below with specific embodiments.

[0051] Example 1 This embodiment provides a quasar-shaped three-dimensional nonionic polyether demulsifier, which is obtained through the following steps: (1) Add 50 g of polyether (purchased from Jiangsu Haian Petrochemical Plant, model 2080, hydroxyl value approximately 18.7 mg KOH / g, EO / PO molar ratio 6:1) and 80 mL of xylene to a 250 mL three-necked flask equipped with a stirrer, thermometer, and nitrogen delivery tube. Turn on the stirrer and introduce nitrogen gas, and heat to 80 °C to completely dissolve the polyether. Then add 1.80 g of acrylic acid (the molar ratio of polyether to acrylic acid is approximately 1:3.0) and 0.10 g of p-toluenesulfonic acid (approximately 0.25% of the molar amount of polyether). Heat the system to 130 °C and reflux for 5 h. After the reaction is complete, cool the system to room temperature to obtain a xylene solution of polyether acrylate, which can be directly used in the next step.

[0052] (2) Transfer all the reaction solution obtained in step (1) above to a 500 mL three-necked flask. Under nitrogen protection, add 100 mL of anhydrous methanol to the system and stir until homogeneous. Then, dissolve 1.20 g of ethylenediamine (based on the initial polyether, the molar ratio of polyether acrylate to ethylenediamine is approximately 1:2.4) in 20 mL of anhydrous methanol and slowly add it dropwise to the reaction system using a constant pressure dropping funnel, controlling the dropping rate to maintain the system temperature below 30 °C. After the addition is complete, continue stirring the reaction at room temperature (25 °C) for 24 h. After the reaction is complete, remove methanol and xylene solvent by rotary evaporation at 60 °C to obtain a viscous liquid. Place the product in a vacuum drying oven at 70 °C and dry for 12 h to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier (SSP). The value of m is 36, and the value of n is 6.

[0053] See Figure 1 The FTIR spectrum shows that the -OH stretching vibration absorption peak in the SSP molecule is at 3446 cm⁻¹. -1 Location. 2887 cm -1 The absorption peak at 1112 cm⁻¹ can be attributed to the stretching vibration of the CH bond in the SSP molecule. -1 The absorption peak at 1550 cm⁻¹ corresponds to the stretching vibration of the ether bond COC. -1 The broad absorption peak at 1734 cm⁻¹ correlates with the symmetric stretching vibration of CN, indicating the successful introduction of N atoms. -1 The C=O bond stretching vibration peak at the point originates from the ester group -COOR, indicating that the ester group was successfully introduced into the SSP molecule. The above results demonstrate that SSP has been successfully synthesized.

[0054] See Figure 2 The thermogravimetric analysis (TG) curve shows that when the temperature increases from 30 °C to 200 °C, the weight loss rate of SSP is 0.65%, which may be attributed to adsorbed moisture and some volatile organic compounds in the material. When the temperature continues to rise to 340 °C, the weight loss of SSP is 1.68%. As the temperature continues to rise from 340 °C to 440 °C, the long-chain structure of SSP is disrupted, the chemical bonds in the molecular chains break, and the compound gradually decomposes. The DTG curve of SSP shows a significant peak at 410 °C, indicating that the weight loss rate of SSP is fastest at this temperature. When the temperature exceeds 510 °C, the remaining weight of SSP is 3.00%, indicating that SSP has almost completely decomposed. The above analysis demonstrates that SSP exhibits good thermal stability, providing a basis for the thermal stability of composite materials used in high-temperature environments.

[0055] Example 2 This embodiment provides a quasar-shaped three-dimensional nonionic polyether demulsifier, which is obtained through the following steps: (1) Add 50 g of polyether (same as in Example 1) and 80 mL of xylene to a 250 mL three-necked flask equipped with a stirrer, thermometer, and nitrogen delivery tube. Turn on the stirrer and introduce nitrogen gas, and heat to 80 °C to completely dissolve the polyether. Then add 2.00 g of acrylic acid (the molar ratio of polyether to acrylic acid is approximately 1:3.3) and 0.12 g of p-toluenesulfonic acid. Heat the system to 125 °C and reflux for 5.5 h. After the reaction is complete, cool the system to room temperature to obtain a xylene solution of polyether acrylate, which can be used directly in the next step.

[0056] (2) Transfer all the reaction solution obtained in step (1) above to a 500 mL three-necked flask. Under nitrogen protection, add 100 mL of anhydrous methanol to the system and stir until homogeneous. Then, dissolve 1.20 g of ethylenediamine (based on the initial polyether, the molar ratio of polyether acrylate to ethylenediamine is approximately 1:2.4) in 20 mL of anhydrous methanol and slowly add it dropwise to the reaction system using a constant pressure dropping funnel, controlling the dropping rate to maintain the system temperature below 30 °C. After the addition is complete, continue stirring the reaction at room temperature (25 °C) for 24 h. After the reaction is complete, remove methanol and xylene solvent by rotary evaporation at 60 °C to obtain a viscous liquid. Place the product in a vacuum drying oven at 70 °C and dry for 12 h to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier.

[0057] Example 3 This embodiment provides a quasar-shaped three-dimensional nonionic polyether demulsifier, which is obtained through the following steps: (1) Add 50 g of polyether segments (same as in Example 1) and 80 mL of xylene to a 250 mL three-necked flask equipped with a stirrer, thermometer, and nitrogen delivery tube. Turn on the stirrer and introduce nitrogen gas, and heat to 80 °C to completely dissolve the polyether. Then add 1.80 g of acrylic acid (the molar ratio of polyether to acrylic acid is approximately 1:3.0) and 0.10 g of p-toluenesulfonic acid. Heat the system to 130 °C and reflux for 5 h. After the reaction is complete, cool the system to room temperature to obtain a xylene solution of polyether acrylate, which can be used directly in the next step.

[0058] (2) Transfer all the reaction solution obtained in step (1) above to a 500 mL three-necked flask. Under nitrogen protection, add 100 mL of anhydrous methanol to the system and stir until homogeneous. Then, dissolve 1.33 g of ethylenediamine (based on the initial polyether, the molar ratio of polyether acrylate to ethylenediamine is approximately 1:2.6) in 20 mL of anhydrous methanol and slowly add it dropwise to the reaction system using a constant pressure dropping funnel, controlling the dropping rate to maintain the system temperature below 30 °C. After the addition is complete, continue stirring the reaction at room temperature (25 °C) for 26 h. After the reaction is complete, remove methanol and xylene solvent by rotary evaporation at 60 °C to obtain a viscous liquid. Place the product in a vacuum drying oven at 70 °C and dry for 12 h to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier.

[0059] Example 4 This embodiment provides a quasar-shaped three-dimensional nonionic polyether demulsifier, which is obtained through the following steps: (1) Add 50 g of polyether (purchased from Jiangsu Haian Petrochemical Plant, model 2060) and 80 mL of xylene to a 250 mL three-necked flask equipped with a stirrer, thermometer, and nitrogen delivery tube. Turn on the stirrer and introduce nitrogen gas, and heat to 80 °C to completely dissolve the polyether. Then add 1.92 g of acrylic acid (the molar ratio of polyether to acrylic acid is approximately 1:3.2) and 0.09 g of p-toluenesulfonic acid (approximately 0.22% of the molar amount of polyether). Heat the system to 135 °C and reflux for 4.5 h. After the reaction is complete, cool the system to room temperature to obtain a xylene solution of polyether acrylate, which can be directly used in the next step.

[0060] (2) Transfer all the reaction solution obtained in step (1) above to a 500 mL three-necked flask. Under nitrogen protection, add 100 mL of anhydrous methanol to the system and stir until homogeneous. Then, dissolve 1.20 g of ethylenediamine (the molar ratio of polyether acrylate to ethylenediamine is approximately 1:2.4 based on the initial polyether) in 20 mL of anhydrous methanol and slowly add it dropwise to the reaction system using a constant pressure dropping funnel, controlling the dropping rate to maintain the system temperature below 30 °C. After the addition is complete, continue stirring the reaction at room temperature (25 °C) for 24 h. After the reaction is complete, remove methanol and xylene solvent by rotary evaporation at 60 °C to obtain a viscous liquid. Place the product in a vacuum drying oven at 70 °C and dry for 12 h to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier.

[0061] Comparative Example 1 A commercially available linear EO-PO block polyether demulsifier (purchased from Jiangsu Haian Petrochemical Plant Co., Ltd., model 2040) with a molecular weight of 3000-4000 was used as a representative of traditional demulsifiers for performance comparison.

[0062] Comparative Example 2 A commercially available linear PEO-PPO block polyether demulsifier (purchased from Guangzhou Zhongwan New Materials Co., Ltd., model OW-10) with a molecular weight of 2000-4000 was used as a representative of traditional demulsifiers for performance comparison.

[0063] Comparative Example 3 The performance of the polyether acrylate described in step (1) of Example 1 was compared using it as a demulsifier.

[0064] Comparative Example 4 This embodiment provides a branched-chain nonionic demulsifier, which is obtained through the following steps: (1) Add 50 g of polyether (model 2080) and 80 mL of xylene to a 250 mL three-necked flask equipped with a stirrer, thermometer, and nitrogen delivery tube. Turn on the stirrer and introduce nitrogen gas, and heat to 80 °C to completely dissolve the polyether. Then add 1.80 g of acrylic acid (the molar ratio of polyether to acrylic acid is approximately 1:3.0) and 0.10 g of p-toluenesulfonic acid (approximately 0.25% of the molar amount of polyether). Heat the system to 130 °C and reflux for 5 h. After the reaction is complete, cool the system to room temperature to obtain a xylene solution of polyether acrylate, which can be used directly in the next step.

[0065] (2) Transfer all the reaction solution obtained in step (1) to a 500 mL three-necked flask. Under nitrogen protection, add 100 mL of anhydrous methanol to the system and stir until homogeneous. Then, dissolve 0.90 g of ethylamine in 20 mL of anhydrous methanol and slowly add it dropwise to the reaction system using a constant pressure dropping funnel, controlling the dropping rate to maintain the system temperature below 30 °C. After the addition is complete, continue stirring the reaction at room temperature (25 °C) for 24 h. After the reaction is complete, remove methanol and xylene solvent by rotary evaporation at 60 °C to obtain a viscous liquid. Place the product in a vacuum drying oven at 70 °C and dry for 12 h to obtain a linear demulsifier.

[0066] Application Example 1 The quasar-shaped three-dimensional nonionic demulsifiers prepared in Examples 1-4 and the demulsifiers in Comparative Examples 1-4 were applied to evaluate the demulsification performance of raw coal gas quench oil emulsions (oil content approximately 20%). The raw coal gas quench oil emulsion is a high-viscosity, high-stability oil-water-solid three-phase coupled system, comprising, by mass fraction: 30%–60% heavy tar, 20%–50% phenol-amine-rich condensate, and 5%–20% asphaltenes and ultrafine coke powder. Asphaltenes and ultrafine coke powder, acting as interfacial active components and structural framework, tightly encapsulate the condensate within the oil phase through their surface activity and interparticle network support, forming a stable emulsion morphology that is extremely difficult to separate into multiple phases.

[0067] Take 50 mL of quenched oil emulsion and place it in a stoppered graduated cylinder. Add a certain concentration of demulsifier and manually shake for 2 min to ensure that the demulsifier is evenly dispersed in the emulsion. Then place the graduated cylinder in a constant temperature water bath at 50 ℃ and observe the demulsification after 10 min and 20 min of settling. The demulsification performance test was conducted according to the petroleum and natural gas industry standard SY / T 5281-2000 "Test Method for Performance of Crude Oil Demulsifier (Bottle Test Method)" to calculate its dehydration rate. The test results are shown in Table 1 below.

[0068] Table 1. Demulsification effect of demulsifiers prepared in different examples and comparative examples.

[0069] Note: "Demulsifier concentration" in the table refers to the concentration of demulsifier in quenched oil emulsion.

[0070] As shown in Table 1, the quasar-shaped three-dimensional nonionic demulsifier provided by this invention exhibits excellent demulsification performance, achieving a dehydration rate of over 90% within 10 minutes and complete demulsification within 20 minutes. In contrast, while the commercially available demulsifiers in Comparative Examples 1-2 show some demulsification effect, their overall efficiency is significantly lower than that of the demulsifier SSP of this invention. This is because commercially available demulsifiers are mostly single-chain structures with simple molecular configurations and weak interfacial forces, making it difficult to effectively disrupt the complex and stable emulsion interfacial film in raw coal gas quenching oil.

[0071] Comparative Example 3 used only polyether acrylate for demulsification, and the demulsification efficiency was significantly lower than that of the embodiments of the present invention, indicating that a single structure is difficult to provide sufficient interfacial active sites. Comparative Example 4 used ethylamine to obtain a single-branched product. Although the demulsification effect was better than that of Comparative Example 3, it was still significantly weaker than that of the SSP of the present invention, proving that the linear structure demulsifier has limited ability, while the multi-branched structure can form multi-point adsorption, which can more effectively weaken the interfacial film strength, thereby significantly improving the demulsification performance.

[0072] Application Example 2 The demulsifier prepared in Example 1 was applied at different concentrations to evaluate the demulsification performance of raw coal gas quench oil emulsion. The raw coal gas quench oil emulsion was the same as that used in Example 1.

[0073] Take 50 mL of raw coal gas quench oil emulsion into a stoppered graduated cylinder, add different concentrations of the nonionic polyether demulsifier prepared in Example 1, manually shake for 2 min to mix evenly, then place it in a constant temperature water bath at 50 ℃ to settle, observe its demulsification, and calculate its dehydration rate according to the petroleum and natural gas industry standard SY / T 5281-2000 "Test Method for Performance of Crude Oil Demulsifier (Bottle Test Method)". The test results are shown in Table 2 below.

[0074] Table 2. Demulsification effect of star-shaped three-dimensional nonionic polyether demulsifier prepared in Example 1 at different concentrations.

[0075] Note: The “demulsifier concentration” in the table refers to the concentration of the demulsifier in the raw coal gas quench oil emulsion.

[0076] As can be seen from the data in Table 2, the quasar-shaped three-dimensional nonionic demulsifier provided in this embodiment of the invention exhibits excellent demulsification performance. Within the tested concentration range, the dehydration rate of the demulsifier first increases and then decreases with increasing concentration, reaching the optimal demulsification effect at 500 mg / L, where the dehydration rate reaches 100% after 20 min of settling. When the concentration exceeds 500 mg / L, because the concentration of the demulsifier is higher than its critical micelle concentration in the system, the molecules will mainly exist in the bulk phase by forming micelles, and its effective adsorption at the oil-water interface will decrease, thus leading to a decrease in demulsification efficiency.

[0077] Application Example 3 The demulsifier prepared in Example 1 was applied to the raw coal gas quench oil emulsion at different temperatures to evaluate its demulsification performance. The raw coal gas quench oil emulsion was the same as that used in Example 1.

[0078] Take 50 mL of raw coal gas quench oil emulsion into a stoppered graduated cylinder, add different concentrations of the quasar-shaped three-dimensional nonionic polyether demulsifier prepared in Example 1, manually shake for 2 min to mix evenly, then place it in a constant temperature water bath at 40 ℃, 50 ℃, 60 ℃ and 70 ℃ for 10 min to settle, observe its demulsification, and calculate its dehydration rate according to the petroleum and natural gas industry standard SY / T5281-2000 "Test Method for Performance of Crude Oil Demulsifier (Bottle Test Method)". The test results are shown in Table 3 below.

[0079] Table 3. Demulsification effect of the demulsifier prepared in Example 1 at different demulsification temperatures.

[0080] Note: "Demulsifier concentration" in the table refers to the concentration of demulsifier in quenched oil emulsion.

[0081] As can be seen from the data in Table 3, the quasar-shaped three-dimensional nonionic polyether demulsifier provided in Example 1 of this invention has excellent demulsification performance. When the temperature is 40 ℃, its dehydration rate is 80.6% within 20 min; when the temperature exceeds 50 ℃, it can achieve complete demulsification (dehydration rate of 100%) within 20 min, which also indicates that the demulsifier has good thermal stability.

[0082] In summary, the quasar-shaped three-dimensional nonionic polyether demulsifier based on polyether segments provided by this invention exhibits excellent demulsification effect on raw coal gas quench oil emulsions, and also demonstrates good demulsification efficiency at high temperatures. The demulsified aqueous phase is colorless and transparent. The quasar-shaped three-dimensional nonionic polyether demulsifier proposed in this invention has high surface activity, good thermal stability, and good dispersibility in the oil phase, making it suitable for water-in-oil emulsions. It also boasts high demulsification efficiency and requires a small injection dosage. Furthermore, the method for preparing the demulsifier in this invention is simple and uses low-cost raw materials.

[0083] This invention provides a demulsifier prepared from polyether segments, which boasts advantages such as simple synthesis process, wide demulsification temperature range, fast demulsification speed, and high efficiency. It is of great significance in solving the problems of complex composition and long demulsification time in raw coal gas quenching oil emulsions. Its unique star-shaped multi-branched structure enhances the interfacial activity and amphiphilicity of the molecules, enabling it to efficiently replace natural surface-active substances at the interface, significantly reduce the oil-water interfacial tension, promote water droplet coalescence, and thus achieve rapid oil-water separation.

[0084] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A demulsifier for use in raw coal gas quenching oil emulsion, characterized in that, The demulsifier is a quasar-shaped three-dimensional nonionic polyether demulsifier comprising 2-4 polyether branches. The demulsifier is prepared by Michael addition reaction of polyether with a polyamine compound after acrylate esterification. The general chemical formula of the demulsifier is as follows: , where m is between 15 and 48, n is between 5 and 8, and m and n are positive integers.

2. The demulsifier according to claim 1, characterized in that, The polyamine compound is one or more of ethylenediamine, diethylenetriamine, and triethylenetetramine.

3. The demulsifier according to claim 1, characterized in that, The polyether is a copolymer obtained by ring-opening polymerization of ethylene oxide and propylene oxide using a polyol as an initiator, wherein the molar ratio of ethylene oxide to propylene oxide is (4-6):

1.

4. A method for preparing a demulsifier as described in any one of claims 1-3, characterized in that, Includes the following steps: Step S1: Dissolve the polyether in an organic solvent and, in the presence of an inert atmosphere and a catalyst, react it with acrylic acid to obtain polyether acrylate. Step S2: Dissolve the polyether acrylate in an alcohol solvent, add a polyamine compound under an inert atmosphere to carry out a Michael addition reaction, remove the solvent after the reaction is completed and dry to obtain a quasar-shaped three-dimensional nonionic polyether demulsifier.

5. The preparation method according to claim 4, characterized in that, In step S1, the molar ratio of the polyether to the acrylic acid is 1:(2.5-4); the amount of catalyst used is 0.2%-0.3% of the molar amount of the polyether.

6. The preparation method according to claim 4, characterized in that, The catalyst is an acidic catalyst selected from p-toluenesulfonic acid, methanesulfonic acid, and benzoic acid monohydrate, and the organic solvent is selected from xylene, toluene, and cyclohexane.

7. The preparation method according to claim 4, characterized in that, The esterification reaction is carried out at a temperature of 120-140℃ for a reaction time of 4-6 h; the Michael addition reaction is carried out at 20-30℃ for a reaction time of 12-36 h.

8. The preparation method according to claim 4, characterized in that, In step S2, the alcohol solvent is anhydrous methanol or anhydrous ethanol, and the molar ratio of the polyether acrylate to the polyamine compound is 1:(2.4-2.6).

9. The use of a demulsifier as described in any one of claims 1-3 or a demulsifier prepared by any one of claims 4-8 in demulsification treatment.

10. The application according to claim 9, characterized in that, The demulsifier is used for demulsification treatment of raw coal gas quench oil emulsion, or other coal chemical oil emulsions containing asphaltenes and resins, and the amount of the demulsifier added to the emulsion is 100-1000 mg / L.

Images