Defoamers and their defoaming method in petrochemical industry

Abstract

The application belongs to the technical field of defoaming agent preparation, and more particularly relates to a defoaming agent and a defoaming method thereof in petrochemical industry. The defoaming agent is a silicone oil defoaming agent, which comprises the following raw materials in parts by weight: 100-120 parts of dimethyl silicone oil, 6-9 parts of silica sol, 3-4 parts of chitosan, and 10-12 parts of emulsifier. The dimethyl silicone oil is first treated by allyl glycidyl ether and then grafted with tyrosine with an isoelectric point of 5.66. The silica sol is first treated by ammonia water and then surface-modified by hexamethyldisilazane. The pH of the defoaming agent is 7.0. The product obtained by the application has the advantages of high defoaming efficiency and short defoaming time.

Description

Technical Field

[0001] This invention belongs to the field of defoamer preparation technology, and more specifically, relates to a defoamer and its defoaming method in petrochemicals. Background Technology

[0002] Crude oil has a complex composition, so the processing technology is also very complex. Foam is generated in delayed coking and aromatics extraction units, which can easily lead to fluctuations in unit production.

[0003] However, the main defoamers currently available are silicone-based defoamers. These standalone defoamers suffer from low defoaming efficiency and long defoaming time. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the problems of low defoaming efficiency and long defoaming time of existing defoamers.

[0005] The purpose of this invention is to provide an antifoaming agent.

[0006] Another object of the present invention is to provide a defoaming method in petrochemicals.

[0007] The above-mentioned objective of this invention is achieved through the following technical solution:

[0008] This invention provides an antifoaming agent, which is a silicone oil-based emulsion. The silicone oil-based emulsion comprises the following raw materials in parts by weight:

[0009] 100-120 parts dimethyl silicone oil, 6-9 parts silica sol, 3-4 parts chitosan, 10-12 parts emulsifier, 110-130 parts deionized water;

[0010] Dimethyl silicone oil is first treated with allyl glycidyl ether and then grafted with tyrosine with an isoelectric point of 5.66.

[0011] The silica sol is first treated with ammonia and then surface modified with hexamethyldisilazane.

[0012] The pH of the defoamer is 7.0.

[0013] The above technical solution first treats dimethyl silicone oil with allyl glycidyl ether, allowing tyrosine (isoelectric point 5.66) to be grafted onto the dimethyl silicone oil molecular chain. Since the defoamer has a pH of 7.0, tyrosine carries a negative charge, enabling it to adsorb the polycations of chitosan. This allows the dimethyl silicone oil molecular chain to adhere to chitosan via electrostatic attraction. Because chitosan has adsorption properties, it can adsorb foam in the system, allowing the dimethyl silicone oil to spread rapidly on the foam film, causing the foam film to rupture and achieving rapid defoaming. Simultaneously, the amino groups in the tyrosine-grafted dimethyl silicone oil can form hydrogen bonds with the hydroxyl groups in the hexamethyldisilazane-modified silica. When the dimethyl silicone oil spreads rapidly on the foam film, the hydrophobic silica... Silica can locally penetrate the surface of bubbles, reducing the local surface tension. Combined with the effect of solid particles, it acts like a needle tip piercing the bubble, accelerating its collapse. Secondly, the silica sol is pretreated with ammonia and then surface-modified with hexamethyldisilazane. The ammonia pretreatment promotes the hydrolysis and polymerization of hydroxyl groups in some silica sol particles, causing some polar Si-OH to dehydrate and condense into less polar Si-O-Si bonds. This makes the silica sol particles more compact and reduces the pore size. On the one hand, at the same concentration, more silica particles can be obtained; on the other hand, the reduced pore size can reduce the amount of gas in the silica, preventing gas from overflowing and promoting foam formation when added to petrochemical plants.

[0014] Furthermore, the viscosity range of dimethyl silicone oil is 200-100,000 centistokes.

[0015] Furthermore, the defoamer also includes 2-3% by weight of dimethyl silicone oil as a solubilizer.

[0016] Furthermore, the solubilizer is selected from one or more of octanol, propanol, and ethanol.

[0017] The above technical solution promotes the dissolution of the surfactant layer of the foam by adding a solubilizer, thereby reducing the surfactant concentration on the surface layer. At the same time, the solubilizer also dissolves into the surfactant adsorption layer, reducing the tightness between surfactant molecules, thus weakening the stability of the foam.

[0018] Furthermore, the emulsifier is prepared by compounding Tween series emulsifiers and Span series emulsifiers at a mass ratio of 1-1.5:1.

[0019] Furthermore, the Tween series emulsifiers are selected from any one of Tween 20, Tween 40, and Tween 60.

[0020] Furthermore, the Span series emulsifiers are selected from any one of Span 40, Span 60 and Span 80.

[0021] Furthermore, the defoamer also includes 3-4% by weight of dimethyl silicone oil soluble starch; the soluble starch is emulsified and modified by mixing Span 60 and Tween 60.

[0022] This invention also provides a defoaming method in petrochemicals, the defoaming method comprising the following steps:

[0023] (1) Preparation of defoamer: Dimethyl silicone oil and silica are stirred at 150°C and then cooled to room temperature to obtain silicone paste complex; chitosan is added to deionized water, then emulsifier is added for ultrasonic dispersion, and silicone paste complex, solubilizer and soluble starch are added and stirred to form emulsion, thus obtaining defoamer;

[0024] (2) Add the defoamer prepared in (1) into a heating box and heat it, and then inject it into a petrochemical device for defoaming.

[0025] The above technical solution promotes the dissolution of chitosan in the system by adding chitosan to deionized water and then adding an emulsifier for ultrasonic dispersion, thereby achieving a better defoaming effect.

[0026] Furthermore, the conditions of the heating chamber in step (2) include: temperature 40-50℃; time 40-60min.

[0027] The above technical solution heats the emulsifier in a heating chamber and controls the temperature and time, thereby causing the gas in the silica pore structure to escape, reducing the presence of incompatible gases in the system, and thus reducing the formation of foam in the system.

[0028] Beneficial effects: (1) In this technical solution, dimethyl silicone oil is first treated with allyl glycidyl ether so that tyrosine with an isoelectric point of 5.66 can be grafted onto the dimethyl silicone oil molecular chain. Since the pH of the defoamer is 7.0, tyrosine carries a negative charge and can adsorb the polycations of chitosan. This allows the dimethyl silicone oil molecular chain to adhere to chitosan through electrostatic interaction. Because chitosan has adsorption properties, it can adsorb the foam in the system, thereby allowing the dimethyl silicone oil to spread quickly on the foam film and cause the foam film to rupture, thus achieving a rapid defoaming effect. At the same time, the amino groups in the dimethyl silicone oil grafted with tyrosine can form hydrogen bonds with the hydroxyl groups in the silica modified by hexamethyldisilazane. When the dimethyl silicone oil spreads quickly on the foam film, Hydrophobic silica can locally penetrate the surface of bubbles, reducing the local surface tension. Combined with the effect of solid particles, it acts like a needle tip piercing the bubble, accelerating its collapse. Secondly, the silica sol is pretreated with ammonia and then surface-modified with hexamethyldisilazane. The ammonia pretreatment promotes the hydrolysis and polymerization of hydroxyl groups in some silica sol particles, causing some polar Si-OH to dehydrate and condense into less polar Si-O-Si bonds. This makes the silica sol particles more compact and reduces the pore size. On the one hand, at the same concentration, more silica particles can be obtained; on the other hand, the reduced pore size can reduce the amount of gas in the silica, preventing gas from overflowing and promoting foam formation when added to petrochemical plants.

[0029] (2) This technical solution promotes the dissolution of the surfactant layer of the foam by adding a solubilizer, thereby reducing the surfactant concentration on the surface layer. At the same time, the solubilizer will also dissolve into the surfactant adsorption layer, reducing the tightness between surfactant molecules, thereby weakening the stability of the foam.

[0030] (3) This technical solution involves adding chitosan to deionized water and then adding an emulsifier for ultrasonic dispersion, thereby promoting the dissolution of chitosan in the system and thus achieving a better defoaming effect.

[0031] (4) This technical solution heats the emulsifier in a heating box and controls the temperature and time, thereby causing the gas in the silica pore structure to overflow, reducing the presence of incompatible gases in the system, and thus reducing the formation of foam in the system. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0033] This invention provides an antifoaming agent, which is a silicone oil-based emulsion. The silicone oil-based emulsion comprises the following raw materials in parts by weight:

[0034] 100-120 parts dimethyl silicone oil, 6-9 parts silica sol, 3-4 parts chitosan, 10-12 parts emulsifier, 110-130 parts deionized water;

[0035] Dimethyl silicone oil is first treated with allyl glycidyl ether and then grafted with tyrosine with an isoelectric point of 5.66.

[0036] The silica sol is first treated with ammonia and then surface modified with hexamethyldisilazane.

[0037] The pH of the defoamer is 7.0.

[0038] The above technical solution first treats dimethyl silicone oil with allyl glycidyl ether, allowing tyrosine (isoelectric point 5.66) to be grafted onto the dimethyl silicone oil molecular chain. Since the defoamer has a pH of 7.0, tyrosine carries a negative charge, enabling it to adsorb the polycations of chitosan. This allows the dimethyl silicone oil molecular chain to adhere to chitosan via electrostatic attraction. Because chitosan has adsorption properties, it can adsorb foam in the system, allowing the dimethyl silicone oil to spread rapidly on the foam film, causing the foam film to rupture and achieving rapid defoaming. Simultaneously, the amino groups in the tyrosine-grafted dimethyl silicone oil can form hydrogen bonds with the hydroxyl groups in the hexamethyldisilazane-modified silica. When the dimethyl silicone oil spreads rapidly on the foam film, the hydrophobic silica... Silica can locally penetrate the surface of bubbles, reducing the local surface tension. Combined with the effect of solid particles, it acts like a needle tip piercing the bubble, accelerating its collapse. Secondly, the silica sol is pretreated with ammonia and then surface-modified with hexamethyldisilazane. The ammonia pretreatment promotes the hydrolysis and polymerization of hydroxyl groups in some silica sol particles, causing some polar Si-OH to dehydrate and condense into less polar Si-O-Si bonds. This makes the silica sol particles more compact and reduces the pore size. On the one hand, at the same concentration, more silica particles can be obtained; on the other hand, the reduced pore size can reduce the amount of gas in the silica, preventing gas from overflowing and promoting foam formation when added to petrochemical plants.

[0039] Furthermore, the viscosity range of dimethyl silicone oil is 200-100,000 centistokes.

[0040] Furthermore, the defoamer also includes 2-3% by weight of dimethyl silicone oil as a solubilizer.

[0041] Furthermore, the solubilizer is selected from one or more of octanol, propanol, and ethanol.

[0042] The above technical solution promotes the dissolution of the surfactant layer of the foam by adding a solubilizer, thereby reducing the surfactant concentration on the surface layer. At the same time, the solubilizer also dissolves into the surfactant adsorption layer, reducing the tightness between surfactant molecules, thus weakening the stability of the foam.

[0043] Furthermore, the emulsifier is prepared by compounding Tween series emulsifiers and Span series emulsifiers at a mass ratio of 1-1.5:1.

[0044] Furthermore, the Tween series emulsifiers are selected from any one of Tween 20, Tween 40, and Tween 60.

[0045] Furthermore, the Span series emulsifiers are selected from any one of Span 40, Span 60 and Span 80.

[0046] Furthermore, the defoamer also includes 3-4% by weight of dimethyl silicone oil soluble starch; the soluble starch is emulsified and modified by mixing Span 60 and Tween 60.

[0047] This invention also provides a defoaming method in petrochemicals, the defoaming method comprising the following steps:

[0048] (1) Preparation of defoamer: Dimethyl silicone oil and silica are stirred at 150°C and then cooled to room temperature to obtain silicone paste complex; chitosan is added to deionized water, then emulsifier is added for ultrasonic dispersion, and silicone paste complex, solubilizer and soluble starch are added and stirred to form emulsion, thus obtaining defoamer;

[0049] (2) Add the defoamer prepared in (1) into a heating box and heat it, and then inject it into a petrochemical device for defoaming.

[0050] The above technical solution promotes the dissolution of chitosan in the system by adding chitosan to deionized water and then adding an emulsifier for ultrasonic dispersion, thereby achieving a better defoaming effect.

[0051] Furthermore, the conditions of the heating chamber in step (2) include: temperature 40-50℃; time 40-60min.

[0052] The above technical solution heats the emulsifier in a heating chamber and controls the temperature and time, thereby causing the gas in the silica pore structure to escape, reducing the presence of incompatible gases in the system, and thus reducing the formation of foam in the system.

[0053] Beneficial effects: (1) In this technical solution, dimethyl silicone oil is first treated with allyl glycidyl ether so that tyrosine with an isoelectric point of 5.66 can be grafted onto the dimethyl silicone oil molecular chain. Since the pH of the defoamer is 7.0, tyrosine carries a negative charge and can adsorb the polycations of chitosan. This allows the dimethyl silicone oil molecular chain to adhere to chitosan through electrostatic interaction. Because chitosan has adsorption properties, it can adsorb the foam in the system, thereby allowing the dimethyl silicone oil to spread quickly on the foam film and cause the foam film to rupture, thus achieving a rapid defoaming effect. At the same time, the amino groups in the dimethyl silicone oil grafted with tyrosine can form hydrogen bonds with the hydroxyl groups in the silica modified by hexamethyldisilazane. When the dimethyl silicone oil spreads quickly on the foam film, Hydrophobic silica can locally penetrate the surface of bubbles, reducing the local surface tension. Combined with the effect of solid particles, it acts like a needle tip piercing the bubble, accelerating its collapse. Secondly, the silica sol is pretreated with ammonia and then surface-modified with hexamethyldisilazane. The ammonia pretreatment promotes the hydrolysis and polymerization of hydroxyl groups in some silica sol particles, causing some polar Si-OH to dehydrate and condense into less polar Si-O-Si bonds. This makes the silica sol particles more compact and reduces the pore size. On the one hand, at the same concentration, more silica particles can be obtained; on the other hand, the reduced pore size can reduce the amount of gas in the silica, preventing gas from overflowing and promoting foam formation when added to petrochemical plants.

[0054] (2) This technical solution promotes the dissolution of the surfactant layer of the foam by adding a solubilizer, thereby reducing the surfactant concentration on the surface layer. At the same time, the solubilizer will also dissolve into the surfactant adsorption layer, reducing the tightness between surfactant molecules, thereby weakening the stability of the foam.

[0055] (3) This technical solution involves adding chitosan to deionized water and then adding an emulsifier for ultrasonic dispersion, thereby promoting the dissolution of chitosan in the system and thus achieving a better defoaming effect.

[0056] (4) This technical solution heats the emulsifier in a heating box and controls the temperature and time, thereby causing the gas in the silica pore structure to overflow, reducing the presence of incompatible gases in the system, and thus reducing the formation of foam in the system.

[0057] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0058] Example 1

[0059] Tyrosine-grafted modified dimethyl silicone oil:

[0060] Weigh out the following components in the indicated weight proportions: 20 parts dimethyl silicone oil, 20 parts tyrosine with an isoelectric point of 5.66, 100 parts dimethyl sulfoxide, 22 parts allyl glycidyl ether, and 5 parts caster catalyst.

[0061] Dimethyl silicone oil was added to dimethyl sulfoxide, followed by allyl glycidyl ether and castor catalyst. The mixture was heated to 80°C for 3 hours under a nitrogen atmosphere. Then, tyrosine with an isoelectric point of 5.66 was added, and the mixture was rapidly cooled to 60°C. The mixture was stirred at 600 rpm for 3 hours. The solvent was then removed by vacuum distillation. The product was then placed in a drying oven at 60°C and dried for 12 hours to obtain tyrosine-grafted modified dimethyl silicone oil.

[0062] Treatment of modified silica sol:

[0063] Weigh out the following components in the indicated weight proportions: 30 parts ammonia, 30 parts hexamethyldisilazane, and 50 parts silica sol.

[0064] In a vacuum environment, ammonia water is first added to silica sol, the temperature is raised to 50°C, and the mixture is stirred at 500 r / min for 24 h. Then the temperature is raised to 100°C and held for 4 h. After cooling to 50°C, hexamethyldisilazane is added and the mixture is stirred at 500 r / min for 15 h to obtain the modified silica sol.

[0065] Emulsified modified soluble starch:

[0066] Weigh out the following components in the indicated weight proportions: 30 parts soluble starch, 10 parts Span 60, 8 parts Tween 60, and 50 parts deionized water.

[0067] Soluble starch was added to deionized water and stirred for 40 minutes at 100 r / min. Then, Span 60 and Tween 60 were added and mixed. The mixture was then ultrasonically dispersed for 1 hour at an ultrasonic frequency of 400 kHz to obtain emulsified modified soluble starch.

[0068] Preparation of defoamer:

[0069] Weigh out the following quantities in order of weight:

[0070] 110 parts of the tyrosine-grafted modified dimethyl silicone oil prepared above, 8 parts of the treated modified silica sol prepared above, 3.5 parts of chitosan, 11 parts of emulsifier, and 120 parts of deionized water.

[0071] The tyrosine-grafted modified dimethyl silicone oil and the modified silica sol prepared above were stirred at 150°C and 800 r / min for 3 h, and then cooled to room temperature to obtain a silicone paste complex. Chitosan was added to deionized water, then an emulsifier was added, and the mixture was ultrasonically dispersed at 400 kHz for 5 h. The silicone paste complex, solubilizer, and the emulsion-modified soluble starch prepared above were then added, and the mixture was stirred at 400 r / min for 2 h to form an emulsion. The pH was adjusted to 7.0 to obtain the defoamer.

[0072] The solubilizer comprises 2.5% of the mass of dimethyl silicone oil; the solubilizer is selected from octanol; the emulsifier is prepared by compounding Tween series emulsifier and Span series emulsifier in a mass ratio of 1.3:1; the Tween series emulsifier is selected from Tween 20; the Span series emulsifier is selected from Span 40; the mass of the emulsified modified soluble starch prepared above is 3.5% of the mass of dimethyl silicone oil.

[0073] Defoaming methods in petrochemicals:

[0074] Defoamer is defined as a material-to-defoamer ratio of 500:1.

[0075] The defoamer prepared above is injected into a heating box and heated, and then injected into a petrochemical plant for defoaming.

[0076] The conditions for the heating chamber include: a temperature of 45°C and a time of 50 minutes; the petrochemical equipment is selected from the aromatics extraction unit.

[0077] Example 2

[0078] Tyrosine-grafted modified dimethyl silicone oil:

[0079] Weigh out the following components in the indicated weight proportions: 20 parts dimethyl silicone oil, 20 parts tyrosine with an isoelectric point of 5.66, 100 parts dimethyl sulfoxide, 22 parts allyl glycidyl ether, and 5 parts caster catalyst.

[0080] Dimethyl silicone oil was added to dimethyl sulfoxide, followed by allyl glycidyl ether and castor catalyst. The mixture was heated to 80°C for 3 hours under a nitrogen atmosphere. Then, tyrosine with an isoelectric point of 5.66 was added, and the mixture was rapidly cooled to 60°C. The mixture was stirred at 600 rpm for 3 hours. The solvent was then removed by vacuum distillation. The product was then placed in a drying oven at 60°C and dried for 12 hours to obtain tyrosine-grafted modified dimethyl silicone oil.

[0081] Treatment of modified silica sol:

[0082] Weigh out the following components in the indicated weight proportions: 30 parts ammonia, 30 parts hexamethyldisilazane, and 50 parts silica sol.

[0083] In a vacuum environment, ammonia water is first added to silica sol, the temperature is raised to 50°C, and the mixture is stirred at 500 r / min for 24 h. Then the temperature is raised to 100°C and held for 4 h. After cooling to 50°C, hexamethyldisilazane is added and the mixture is stirred at 500 r / min for 15 h to obtain the modified silica sol.

[0084] Emulsified modified soluble starch:

[0085] Weigh out the following components in the indicated weight proportions: 30 parts soluble starch, 8 parts Span 60, 10 parts Tween 60, and 50 parts deionized water.

[0086] Soluble starch was added to deionized water and stirred for 40 minutes at 100 r / min. Then, Span 60 and Tween 60 were added and mixed. The mixture was then ultrasonically dispersed for 1 hour at an ultrasonic frequency of 400 kHz to obtain emulsified modified soluble starch.

[0087] Preparation of defoamer:

[0088] Weigh out the following quantities in order of weight:

[0089] 100 parts of the tyrosine-grafted modified dimethyl silicone oil prepared above, 6 parts of the treated modified silica sol prepared above, 3 parts of chitosan, 10 parts of emulsifier, and 110 parts of deionized water.

[0090] The tyrosine-grafted modified dimethyl silicone oil and the modified silica sol prepared above were stirred at 150°C and 800 r / min for 3 h, and then cooled to room temperature to obtain a silicone paste complex. Chitosan was added to deionized water, then an emulsifier was added, and the mixture was ultrasonically dispersed at 400 kHz for 5 h. The silicone paste complex, solubilizer, and the emulsion-modified soluble starch prepared above were then added, and the mixture was stirred at 400 r / min for 2 h to form an emulsion. The pH was adjusted to 7.0 to obtain the defoamer.

[0091] The solubilizer is 2% of the mass of dimethyl silicone oil; the solubilizer is selected from propanol; the emulsifier is prepared by compounding Tween series emulsifier and Span series emulsifier in a mass ratio of 1:1; the Tween series emulsifier is selected from Tween 40; the Span series emulsifier is selected from Span 60; the mass of the emulsified modified soluble starch prepared above is 3% of the mass of dimethyl silicone oil.

[0092] Defoaming methods in petrochemicals:

[0093] Defoamer is defined as a material-to-defoamer ratio of 500:1.

[0094] The defoamer prepared above is injected into a heating box and heated, and then injected into a petrochemical plant for defoaming.

[0095] The conditions for the heating chamber include: a temperature of 50°C and a time of 40 minutes; the petrochemical equipment is selected from the aromatics extraction unit.

[0096] Example 3

[0097] Tyrosine-grafted modified dimethyl silicone oil:

[0098] Weigh out the following components in the indicated weight proportions: 20 parts dimethyl silicone oil, 20 parts tyrosine with an isoelectric point of 5.66, 100 parts dimethyl sulfoxide, 22 parts allyl glycidyl ether, and 5 parts caster catalyst.

[0099] Dimethyl silicone oil was added to dimethyl sulfoxide, followed by allyl glycidyl ether and castor catalyst. The mixture was heated to 80°C for 3 hours under a nitrogen atmosphere. Then, tyrosine with an isoelectric point of 5.66 was added, and the mixture was rapidly cooled to 60°C. The mixture was stirred at 600 rpm for 3 hours. The solvent was then removed by vacuum distillation. The product was then placed in a drying oven at 60°C and dried for 12 hours to obtain tyrosine-grafted modified dimethyl silicone oil.

[0100] Treatment of modified silica sol:

[0101] Weigh out the following components in the indicated weight proportions: 30 parts ammonia, 30 parts hexamethyldisilazane, and 50 parts silica sol.

[0102] In a vacuum environment, ammonia water is first added to silica sol, the temperature is raised to 50°C, and the mixture is stirred at 500 r / min for 24 h. Then the temperature is raised to 100°C and held for 4 h. After cooling to 50°C, hexamethyldisilazane is added and the mixture is stirred at 500 r / min for 15 h to obtain the modified silica sol.

[0103] Emulsified modified soluble starch:

[0104] Weigh out the following components in the indicated weight proportions: 30 parts soluble starch, 10 parts Span 60, 8 parts Tween 60, and 50 parts deionized water.

[0105] Soluble starch was added to deionized water and stirred for 40 minutes at 100 r / min. Then, Span 60 and Tween 60 were added and mixed. The mixture was then ultrasonically dispersed for 1 hour at an ultrasonic frequency of 400 kHz to obtain emulsified modified soluble starch.

[0106] Preparation of defoamer:

[0107] Weigh out the following quantities in order of weight:

[0108] 120 parts of the tyrosine-grafted modified dimethyl silicone oil prepared above, 9 parts of the treated modified silica sol prepared above, 4 parts of chitosan, 12 parts of emulsifier, and 130 parts of deionized water.

[0109] The tyrosine-grafted modified dimethyl silicone oil and the modified silica sol prepared above were stirred at 150°C and 800 r / min for 3 h, and then cooled to room temperature to obtain a silicone paste complex. Chitosan was added to deionized water, then an emulsifier was added, and the mixture was ultrasonically dispersed at 400 kHz for 5 h. The silicone paste complex, solubilizer, and the emulsion-modified soluble starch prepared above were then added, and the mixture was stirred at 400 r / min for 2 h to form an emulsion. The pH was adjusted to 7.0 to obtain the defoamer.

[0110] The solubilizer is 2% of the mass of dimethyl silicone oil; the solubilizer is selected from ethanol; the emulsifier is prepared by compounding Tween series emulsifier and Span series emulsifier in a mass ratio of 1.5:1; the Tween series emulsifier is selected from Tween 60; the Span series emulsifier is selected from Span 80; the mass of the emulsified modified soluble starch prepared above is 4% of the mass of dimethyl silicone oil.

[0111] Defoaming methods in petrochemicals:

[0112] Defoamer is defined as a material-to-defoamer ratio of 500:1.

[0113] The defoamer prepared above is injected into a heating box and heated, and then injected into a petrochemical plant for defoaming.

[0114] The conditions for the heating chamber include: a temperature of 50°C and a time of 60 minutes; the petrochemical equipment is selected from the aromatics extraction unit.

[0115] Example 4

[0116] The difference between this embodiment and Example 1 is that no solubilizer was added, while all other conditions remained the same.

[0117] Example 5

[0118] The difference between this embodiment and Example 1 is that the solubilizer is prepared by mixing octanol and ethanol in a 1:1 mass ratio, while the other conditions remain unchanged.

[0119] Example 6

[0120] The difference between this embodiment and Example 1 is that the emulsifier is selected from Tween 20, while the other conditions remain the same.

[0121] Example 7

[0122] The difference between this embodiment and Example 1 is that the emulsifier is selected from Span 40, while the other conditions remain the same.

[0123] Example 8

[0124] The difference between this embodiment and Example 1 is that no soluble starch was added, while all other conditions remained the same.

[0125] Example 9

[0126] The difference between this embodiment and Example 1 is that the soluble starch was not emulsified and modified by mixing Span 60 and Tween 60, while the other conditions remained the same.

[0127] Comparative Example 1

[0128] The difference between this comparative example and Example 1 is that chitosan was not added, while all other conditions remained the same.

[0129] Comparative Example 2

[0130] The difference between this comparative example and Example 1 is that the dimethyl silicone oil was not grafted with tyrosine, which has an isoelectric point of 5.66, while the other conditions remained the same.

[0131] Comparative Example 3

[0132] The difference between this comparative example and Example 1 is that the silica sol was not surface-modified with ammonia and hexamethyldisilazane, while the other conditions remained the same.

[0133] Comparative Example 4

[0134] The difference between this comparative example and Example 1 is that the silica sol was only surface modified with hexamethyldisilazane, while the other conditions remained unchanged.

[0135] Comparative Example 5

[0136] The difference between this comparative example and Example 1 is that dimethyl silicone oil was grafted with tyrosine, which has an isoelectric point of 7.0, while the other conditions remained the same.

[0137] Comparative Example 6

[0138] The difference between this comparative example and Example 1 is that the pH of the defoamer was adjusted to the isoelectric point of tyrosine, 5.66.

[0139] The products obtained in Examples 1-9 and Comparative Examples 1-6 were subjected to performance tests. The specific test methods and results are as follows:

[0140] Static defoaming time test: Weigh the defoamer according to the material to defoamer ratio of 500:1, then inject the prepared defoamer into a heating box and heat it at 50℃ for 60 minutes. Then inject it into an aromatic hydrocarbon extraction device for defoaming. Record the time from the disappearance of foam to the appearance of the liquid surface, in seconds. The shorter the defoaming time, the higher the defoaming efficiency.

[0141] The specific test results are shown in Table 1;

[0142] Table 1: Product Performance Test Results

[0143] Defoaming time / s Example 1 0.10 Example 2 0.10 Example 3 0.11 Example 4 0.26 Example 5 0.11 Example 6 0.14 Example 7 0.14 Example 8 0.20 Example 9 0.19 Comparative Example 1 0.58 Comparative Example 2 0.48 Comparative Example 3 0.63 Comparative Example 4 0.35 Comparative Example 5 0.46 Comparative Example 6 0.49

[0144] As can be seen from the test results in Table 1, the product obtained by the present invention has the advantages of high defoaming efficiency and short defoaming time.

[0145] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A defoamer, characterized in that, The defoamer is a silicone oil-based emulsion, which comprises the following raw materials in parts by weight: 100-120 parts dimethyl silicone oil, 6-9 parts silica sol, 3-4 parts chitosan, 10-12 parts emulsifier, 110-130 parts deionized water; Dimethyl silicone oil is first treated with allyl glycidyl ether and then grafted with tyrosine with an isoelectric point of 5.

66. The silica sol is first treated with ammonia and then surface modified with hexamethyldisilazane. The pH of the defoamer is 7.

0.

2. The defoamer according to claim 1, characterized in that, Dimethyl silicone oil has a viscosity range of 200-100,000 centistokes.

3. The defoamer according to claim 1, characterized in that, The defoamer also includes a solubilizer of 2-3% by weight of dimethyl silicone oil.

4. The defoamer according to claim 3, characterized in that, The solubilizer is selected from one or more of octanol, propanol, and ethanol.

5. The defoamer according to claim 1, characterized in that, The emulsifier is prepared by compounding Tween series emulsifiers and Span series emulsifiers at a mass ratio of 1-1.5:

1.

6. The defoamer according to claim 5, characterized in that, The Tween series emulsifiers are selected from any one of Tween 20, Tween 40 and Tween 60.

7. The defoamer according to claim 5, characterized in that, The Span series emulsifiers are selected from any one of Span 40, Span 60 and Span 80.

8. The defoamer according to claim 1, characterized in that, The defoamer also includes 3-4% by weight of dimethyl silicone oil and soluble starch; the soluble starch is emulsified and modified by mixing Span 60 and Tween 60.

9. A defoaming method in petrochemicals, characterized in that, The defoaming method using the defoamer according to any one of claims 1-8 includes the following steps: (1) Preparation of defoamer: The prepared tyrosine-grafted modified dimethyl silicone oil and the prepared treated modified silica sol were stirred at 150°C and then cooled to room temperature to obtain silicone paste complex; chitosan was added to deionized water, then emulsifier was added for ultrasonic dispersion, and then silicone paste complex, solubilizer and soluble starch were added and stirred to form emulsion, thus obtaining defoamer; (2) Add the defoamer prepared in (1) into a heating box and heat it, and then inject it into a petrochemical device for defoaming.

10. The defoaming method in petrochemicals according to claim 9, characterized in that, The conditions for the heating chamber in step (2) include: temperature 40-50℃; time 40-60min.