Surfactant preparation system applicable to cleaning fracturing fluid

Abstract

The present invention relates to the technical field of petroleum engineering and chemical processing equipment, and particularly relates to a surfactant preparation system suitable for clean fracturing fluid; it includes a reaction kettle, which is used to add tertiary amine and chloroacetic acid solution for mixing reaction; and the mixture of tertiary amine and chloroacetic acid solution in the reaction kettle is added into a distillation column through a delivery pump for distillation and stratification. In the present invention, first, the tertiary amine and chloroacetic acid solution are mixed, stirred vigorously, and heated to the reflux temperature for distillation to form an emulsion; the emulsion has a certain stability, that is, it will not immediately stratify even if the stirring is stopped; then sodium hydroxide solution is slowly added to the emulsion to react with the emulsion in situ to generate sodium chloroacetate, which undergoes a quaternization reaction with the tertiary amine, capable of inhibiting the hydrolysis of sodium chloroacetate and improving the final yield of the surfactant; and as the reaction proceeds, the generated betaine also acts as an emulsifier, and no organic solvent needs to be added during the preparation process.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum engineering and chemical processing equipment, and particularly to a surfactant preparation system suitable for clean fracturing fluid. Background Art

[0002] Currently, the synthesis of surfactants (betaines) usually adopts the sodium chloroacetate + water medium method or the ethyl chloroacetate + organic solvent method; among them, the sodium chloroacetate + water medium method is to react sodium chloroacetate with tertiary amine in an aqueous medium under a weakly alkaline environment, and by controlling a certain molar ratio of raw materials, reaction temperature and reaction time, the target product is obtained; since chloroacetic acid in industrial products is more easily stored and transported than sodium chloroacetate, it is necessary to prepare sodium chloroacetate in advance: ClCH 2 COOH + NaOH → ClCH 2 COONa + H 2 O + Q (heat); control the pH value of sodium chloroacetate to 7 - 8, and then carry out the quaternization reaction with sodium chloroacetate and tertiary amine: an alkaline condition is favorable for the quaternization reaction, at this time the carbon-chlorine bond is easily broken and the carbon-nitrogen bond is easily formed; however, sodium chloroacetate is easily decomposed under the reaction conditions in this reaction, resulting in a reduction in the yield of the final product; while the purpose of the ethyl chloroacetate + organic solvent method is to change the heterogeneous reaction into a homogeneous reaction, using n-butyl ketone as the solvent, replacing chloroacetic acid with ethyl chloroacetate, reacting at the reflux temperature (80 °C) for a certain time, then distilling out the solvent, extracting the unreacted tertiary amine and ethyl chloroacetate with n-hexane to obtain the intermediate product quaternary ammonium chloride ester, and then hydrolyzing, desalting and removing the solvent in an ethanol solution of sodium hydroxide to obtain a light yellow viscous product; but due to the use of organic solvents, the problem of recovering organic solvents is involved in the later stage of the process, greatly increasing the cost of the entire process.

[0003] Therefore, the present invention provides a surfactant preparation system suitable for clean fracturing fluid, which is used to inhibit the hydrolysis of sodium chloroacetate and overcome the problem of recovering organic solvents in the later stage of the process. Summary of the Invention

[0004] The purpose of the present invention is to provide a surfactant preparation system suitable for clean fracturing fluid, which mainly solves the technical problems mentioned in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A surfactant preparation system suitable for clean fracturing fluid, the preparation system includes;

[0007] A reaction kettle, which is used to add tertiary amine and chloroacetic acid solution for mixing reaction;

[0008] A distillation column, the feed end of the distillation column is connected to the discharge end of the reaction kettle, and a mixture of tertiary amine and chloroacetic acid solution in the reaction kettle is added into the distillation column through a transfer pump, so that the distillation column heats the mixture of tertiary amine and chloroacetic acid solution to 90°C - 110°C for distillation and layering to obtain an intermediate and clarified water;

[0009] A reactor, the feed end of the reactor is connected to the discharge end of the distillation column, and the reactor is used to add the intermediate and sodium hydroxide solution for quaternization reaction to obtain a surfactant pre-product;

[0010] A boiler, the gas outlet end of the boiler is connected to the gas inlet end of the distillation column, and the steam generated in the boiler is pressurized by an electric pressure pump and then pumped into the distillation column to heat the internal temperature of the distillation column to 90°C - 110°C.

[0011] Preferably, the preparation system further includes;

[0012] A crusher, the feed end of the crusher is connected to the discharge end of the reactor, and the crusher is used to crush the surfactant pre-product;

[0013] A dryer, the feed end of the dryer is connected to the discharge end of the crusher, and the dryer is used to dry the crushed surfactant pre-product to obtain a powdery surfactant;

[0014] A product tank, the feed end of the product tank is connected to the discharge end of the dryer, and the product tank is used to store the powdery surfactant.

[0015] Preferably, a mixing container is arranged between the distillation column and the reactor, the feed end of the mixing container is connected to the discharge end of the distillation column, the discharge end of the mixing container is connected to the feed end of the reactor, and the mixing container is used to naturally cool the intermediate, so that the temperature of the intermediate drops from 90°C - 110°C to 70°C - 90°C.

[0016] Preferably, a stirring structure is arranged inside the mixing container to stir the intermediate, so that the intermediate will not immediately layer during the natural cooling process.

[0017] Preferably, an exhaust port is arranged at the top of the distillation column, and a cooling tower is connected to the exhaust port. The cooling tower is used to cool the high-temperature gas discharged from the distillation column and then discharge it;

[0018] The bottom water tank of the cooling tower is communicated with the exhaust port of the distillation tower. After the use of the distillation tower is completed, the water in the bottom water tank of the cooling tower is pumped into the distillation tower by a water pump for backwashing.

[0019] Preferably, a drain port is provided at the bottom end of the distillation tower, and the drain port is respectively connected with a drain pipe, a reflux pipe and a make-up water pipe through an electromagnetic four-way valve;

[0020] The other end of the drain pipe is connected with a waste water collection bucket for recovering the waste water generated after backwashing in the distillation tower;

[0021] The other end of the reflux pipe is connected with a water tank for recovering the clarified water formed after stratification in the distillation tower;

[0022] The other end of the make-up water pipe is communicated with the water inlet of the boiler for pumping the clarified water in the water tank into the boiler by a water pump for water make-up.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] In the present invention, by changing the feeding method of the raw materials for preparing the surfactant, the molar ratio of tertiary amine to chloroacetic acid solution is first mixed at 1:1 - 1.10, stirred vigorously, and distilled and heated to the reflux temperature (90°C - 110°C) to form an emulsion; the emulsion has a certain stability, and even if the stirring stops, it will not immediately stratify; then sodium hydroxide solution is slowly added to the emulsion to react with the emulsion in situ to generate sodium chloroacetate, and quaternization reaction is carried out with the tertiary amine, which can inhibit the hydrolysis of sodium chloroacetate and improve the final yield of the surfactant; at the same time, as the reaction proceeds, the generated betaine also acts as an emulsifier, so that no organic solvent needs to be added during the preparation process of the preparation system, and thus there is no need to recover the organic solvent in the later stage of the process, which can reduce the cost of the whole process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic structural diagram of a surfactant preparation system for clean fracturing fluid applicable to the present invention;

[0027] In the figure: 1, reaction kettle; 2, distillation column; 3, reactor; 4, boiler; 5, grinder; 6, dryer; 7, product tank; 8, mixing container; 9, cooling tower; 10, drain pipe; 11, reflux pipe; 12, make-up water pipe; 13, water tank; 14, waste water collection bucket; 15, chloroacetic acid solution storage tank; 16, sodium hydroxide solution storage tank; the direction of a is the feeding direction of tertiary amine. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] As Figure 1As shown in the figure, the present invention provides a surfactant preparation system applicable to cleaning fracturing fluids. The preparation system includes a reaction kettle 1, a distillation column 2, a reactor 3, a boiler 4, a pulverizer 5, a dryer 6, and a product tank 7. A chloroacetic acid solution storage tank 15 is installed at the feeding end of the reaction kettle 1. The chloroacetic acid solution in the chloroacetic acid solution storage tank 15 is pumped into the reaction kettle 1 through a delivery pump. At the same time, tertiary amine is added into the reaction kettle 1, and the molar ratio of the tertiary amine to the chloroacetic acid solution is added into the reaction kettle 1 at 1:1 - 1.10 for a mixing reaction. A stirring structure is arranged in the reaction kettle 1 to mix and stir the tertiary amine and the chloroacetic acid solution added into the reaction kettle 1, so that the tertiary amine and the chloroacetic acid solution are evenly mixed; the feeding end of the distillation column 2 is connected to the discharging end of the reaction kettle 1, and the mixture of the tertiary amine and the chloroacetic acid solution in the reaction kettle 1 is added into the distillation column 2 through a delivery pump, so that the distillation column 2 heats the mixture of the tertiary amine and the chloroacetic acid solution to the reflux temperature (90°C - 110°C) for distillation layering to obtain an intermediate and clarified water. The intermediate is an emulsion with a certain stability and will not immediately layer even if stirring stops; the feeding end of the reactor 3 is connected to the discharging end of the distillation column 2. A sodium hydroxide solution storage tank 16 is also connected to the feeding end of the reactor 3. The sodium hydroxide solution in the sodium hydroxide solution storage tank 16 is pumped into the reactor 3 through a delivery pump, so that the intermediate and the sodium hydroxide solution are added into the reactor 3 for quaternization reaction, and the molar ratio of the tertiary amine to sodium chloroacetate is reacted at 1:1 - 1.10 to obtain a surfactant pre-product; the gas outlet end of the boiler 4 is connected to the gas inlet end of the distillation column 2, and the steam generated in the boiler 4 is pressurized by an electric pressure pump and then pumped into the distillation column 2 to heat the internal temperature of the distillation column 2 to 90°C - 110°C; the feeding end of the pulverizer 5 is connected to the discharging end of the reactor 3, and the pulverizer 5 is used to pulverize the surfactant pre-product; the feeding end of the dryer 6 is connected to the discharging end of the pulverizer 5, and the dryer 6 is used to dry the pulverized surfactant pre-product to obtain a powdery surfactant; the feeding end of the product tank 7 is connected to the discharging end of the dryer 6, and the product tank 7 is used to store the powdery surfactant.

[0030] Further, a mixing container 8 is arranged between the distillation column 2 and the reactor 3. The feeding end of the mixing container 8 is connected to the discharging end of the distillation column 2, and the discharging end of the mixing container 8 is connected to the feeding end of the reactor 3. The mixing container 8 is used to naturally cool the intermediate, so that the temperature of the intermediate drops from 90°C - 100°C to 70°C - 90°C; a stirring structure is arranged inside the mixing container 8 to stir the intermediate, so that the intermediate will not immediately layer during the natural cooling process.

[0031] Further, an exhaust port is provided at the top end of the distillation column 2, and a cooling tower 9 is connected to the exhaust port. The cooling tower 9 is used to cool the high-temperature gas discharged from the distillation column 2 and then discharge it. The bottom water tank of the cooling tower 9 is communicated with the exhaust port of the distillation column 2, and is used to pump the water in the bottom water tank of the cooling tower 9 into the distillation column 2 through a water pump for backwashing after the use of the distillation column 2 is completed.

[0032] Further, a drain port is provided at the bottom end of the distillation column 2. The drain port is respectively connected to a drain pipe 10, a reflux pipe 11 and a make-up water pipe 12 through an electromagnetic four-way valve. The other end of the drain pipe 10 is connected to a waste water collection bucket 14 for recovering the waste water generated after backwashing in the distillation column 2, which is convenient for centralized treatment. The other end of the reflux pipe 11 is connected to a water tank 13. After the intermediate in the distillation column 2 is discharged, the electromagnetic four-way valve is controlled to connect the drain port of the distillation column 2 with the reflux pipe 11, so that the water layer at the bottom of the distillation column 2 is discharged into the water tank 13 through the reflux pipe 11 for recovering and reusing the clarified water formed after stratification in the distillation column 2. The other end of the make-up water pipe 12 is communicated with the water inlet of the boiler 4. After all the water in the distillation column 2 is discharged, the electromagnetic four-way valve is controlled to connect the reflux pipe 11 with the make-up water pipe 12, and then the clarified water in the water tank 13 is pumped into the boiler 4 through a water pump for water replenishment. After the water replenishment is completed, the electromagnetic four-way valve is closed.

[0033] As a preferred embodiment of the present invention, first, the molar ratio of tertiary amine to chloroacetic acid solution is added to the reaction kettle 1 at 1:1.05 for mixing reaction. Then, the mixture of tertiary amine and chloroacetic acid solution in the reaction kettle 1 is added to the distillation column 2 through a transfer pump, so that the distillation column 2 heats the mixture of tertiary amine and chloroacetic acid solution to 100 °C for distillation and stratification to obtain an intermediate and clarified water. Then, the intermediate is added to the mixing container 8 for natural cooling, so that the temperature of the intermediate drops from 100 °C to 85 °C. Then, the intermediate is added to the reactor 3, and then sodium hydroxide solution is slowly added to the intermediate to generate sodium chloroacetate in situ with the intermediate in the reactor 3 for quaternization reaction with the tertiary amine. The hydrolysis of sodium chloroacetate can be inhibited during the reaction process, and the final yield of the surfactant can be improved. Among them, the molar ratio of tertiary amine to sodium chloroacetate is 1:1.05 for reaction, and the reaction time is 7 h. At the same time, as the reaction proceeds, the generated betaine also acts as an emulsifier, so that no organic solvent needs to be added during the preparation process of the preparation system. Therefore, there is no need to recover the organic solvent in the later stage of the process, which can reduce the cost of the whole process.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A surfactant preparation system applicable to clean fracturing fluid, characterized in that: The preparation system includes; A reaction kettle (1) for adding tertiary amine and chloroacetic acid solution for mixing reaction; A distillation column (2), the feed end of the distillation column (2) is connected to the discharge end of the reaction kettle (1), and the mixture of tertiary amine and chloroacetic acid solution in the reaction kettle (1) is added into the distillation column (2) through a delivery pump, so that the distillation column (2) heats the mixture of tertiary amine and chloroacetic acid solution to 90°C - 110°C for distillation and layering to obtain an intermediate and clarified water; A reactor (3), the feed end of the reactor (3) is connected to the discharge end of the distillation column (2), and the reactor (3) is used for adding the intermediate and sodium hydroxide solution for quaternization reaction to obtain a surfactant preproduct; A boiler (4), the gas outlet end of the boiler (4) is connected to the gas inlet end of the distillation column (2), and the steam generated in the boiler (4) is pressurized by an electric pressure pump and then pumped into the distillation column (2) to heat the internal temperature of the distillation column (2) to 90°C - 110°C; A mixing container (8) is arranged between the distillation column (2) and the reactor (3), the feed end of the mixing container (8) is connected to the discharge end of the distillation column (2), the discharge end of the mixing container (8) is connected to the feed end of the reactor (3), and the mixing container (8) is used for naturally cooling the intermediate, so that the temperature of the intermediate drops from 90°C - 110°C to 70°C - 90°C.

2. The surfactant preparation system applicable to clean fracturing fluid according to claim 1, characterized in that: The preparation system further includes; A crusher (5), the feed end of the crusher (5) is connected to the discharge end of the reactor (3), and the crusher (5) is used for crushing the surfactant preproduct; A dryer (6), the feed end of the dryer (6) is connected to the discharge end of the crusher (5), and the dryer (6) is used for drying the crushed surfactant preproduct to obtain a powdery surfactant; A product tank (7), the feed end of the product tank (7) is connected to the discharge end of the dryer (6), and the product tank (7) is used for storing the powdery surfactant.

3. The surfactant preparation system applicable to clean fracturing fluid according to claim 1, characterized in that: A stirring structure is arranged inside the mixing container (8) for stirring the intermediate, so that the intermediate will not be immediately layered during the natural cooling process.

4. The surfactant preparation system applicable to clean fracturing fluid according to claim 1, characterized in that: An exhaust port is arranged at the top of the distillation column (2), and a cooling tower (9) is connected to the exhaust port. The cooling tower (9) is used for cooling the high-temperature gas discharged from the distillation column (2) and then discharging it; The bottom water tank of the cooling tower (9) is communicated with the exhaust port of the distillation tower (2), and is used to pump the water in the bottom water tank of the cooling tower (9) into the distillation tower (2) through a water pump for backwashing after the use of the distillation tower (2).

5. The surfactant preparation system applicable to cleaning fracturing fluid according to claim 4, characterized in that: A drain port is arranged at the bottom end of the distillation tower (2), and the drain port is respectively connected with a drain pipe (10), a return pipe (11) and a make-up water pipe (12) through an electromagnetic four-way valve; The other end of the drain pipe (10) is connected with a waste water collection bucket (14) for recovering the waste water generated after backwashing in the distillation tower (2); The other end of the return pipe (11) is connected with a water tank (13) for recovering the clarified water formed after stratification in the distillation tower (2); The other end of the make-up water pipe (12) is communicated with the water inlet of the boiler (4) for pumping the clarified water in the water tank (13) into the boiler (4) through a water pump for water make-up.

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