Defoaming agent for oilfield sewage treatment and preparation method thereof

Abstract

The invention belongs to the technical field of oilfield ecological environment treatment, and particularly relates to a defoaming agent for oilfield sewage treatment and a preparation method of the defoaming agent. The preparation method comprises the following steps: sequentially adding bis (3-trimethoxysilylpropyl) amine, a catalyst and halohydrin into a high-temperature and high-pressure reactor, mixing and stirring at normal temperature for 30-60 minutes to form a mixed emulsion, introducing nitrogen, vacuumizing and replacing, heating to 80-100 DEG C, circularly introducing ethylene oxide, continuously heating to 120-140 DEG C, keeping the temperature to react for 2-3 hours, and cooling to room temperature to obtain the high-temperature-resistant epoxy resin. And introducing cold nitrogen, cooling to 40-50 DEG C, adding the compound emulsifier, and uniformly stirring and mixing to obtain the product defoaming agent. The defoaming agent disclosed by the invention has the advantages of simple preparation process, low cost and good oil field oily sewage treatment effect.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield ecological environment management, and specifically relates to a defoaming agent for oilfield sewage treatment and a preparation method thereof. Background Art

[0002] Crude oil developed from oil fields generally contains water and needs to be dehydrated before refining. The wastewater produced by dehydration carries a small amount of crude oil. After being treated by a sewage treatment device, it meets the discharge standards. During the aeration process of sewage treatment, a large amount of foam will be generated due to the oil in the water, which seriously affects the sewage treatment effect. The domestic oilfield oily wastewater treatment process generally first performs basic oil removal, then aeration and biochemical treatment to ensure that the wastewater meets the discharge standards.

[0003] At present, commonly used defoamers are mainly mineral oil and silicone emulsions, among which silicone emulsions are widely used due to their good defoaming performance and low dosage. CN108726913A discloses a silicone ether composite defoamer and its preparation method and application, which is obtained by stirring and emulsifying 15%-25% polyoxysilane, 15%-25% polyether, 2%-5% hydrophobic white carbon black, 2%-5% composite emulsifier, 1%-2% stabilizer and a small amount of water; CN110314417B discloses a silicone defoamer, which is obtained by stirring and emulsifying 5-10 parts of hydroxy silicone oil, 20-50 parts of polymethylsiloxane, 1-3 parts of thickener, 50-100 parts of water, 6-8 parts of emulsifying dispersant, 1-5 parts of white carbon black, 30-60 parts of modified polyether. Emulsification; CN115518418B discloses a mineral oil defoamer and a preparation method thereof, which is compounded with 50-90 parts of mineral oil, 5-20 parts of zwitterionic emulsifier, 5-20 parts of nonionic emulsifier, 1-10 parts of perfluoropolyether, 0.3-5 parts of defoamer and 0.5-5 parts of thickener; CN109200632A discloses a multifunctional non-toxic high-temperature organosilicon modified polyether industrial defoamer and a preparation method thereof, which is compounded with 50-90 parts of polyether, 10-50 parts of modified organosilicon simple body and 5-15 parts of sulfuric acid, and has the characteristics of high temperature resistance.

[0004] Generally speaking, the existing defoaming agents have their own strengths, but there are problems such as long defoaming time and poor defoaming effect in the treatment of oilfield oily wastewater, which leads to high concentration of defoaming agents and affects the stable operation of sewage treatment facilities. Summary of the invention

[0005] To this end, the embodiment of the present invention provides a defoaming agent for oilfield wastewater treatment and a preparation method thereof, so as to achieve the purpose of stable operation, standard discharge and reduced treatment cost of oily wastewater treatment facilities. In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

[0006] A defoaming agent for oilfield wastewater treatment and a preparation method thereof, the method comprising the following steps:

[0007] (1) adding di(3-trimethoxysilylpropyl)amine, a catalyst, and haloethanol in a high temperature and high pressure reactor in sequence, and mixing and stirring at room temperature for 30-60 minutes to form a mixed emulsion;

[0008] (2) introducing nitrogen, evacuating and replacing 2-3 times, raising the temperature to 80-100°C, circulating ethylene oxide, continuing to raise the temperature to 120-140°C, continuously stirring, and keeping the temperature for reaction for 2-3 hours;

[0009] (3) Stop introducing ethylene oxide, introduce cold nitrogen to lower the temperature of the reactor to 40-50° C., add the composite emulsifier and continue stirring for 20-30 minutes to obtain a defoaming agent.

[0010] Furthermore, in step (1), the molar ratio of di(3-trimethoxysilylpropyl)amine, haloethanol and ethylene oxide is 1:(2-3):(10-12).

[0011] Furthermore, the haloethanol in step (1) is chloroethanol.

[0012] Furthermore, the catalyst in step (1) is a mixture of Lewis acid and boron fluoride.

[0013] Furthermore, the mass ratio of the catalyst to di(3-trimethoxysilylpropyl)amine in step (1) is (0.1-0.2):1.

[0014] Furthermore, the composite emulsifier in step (3) is a mixture of a lipophilic emulsifier Span-80 and a hydrophilic emulsifier Tween-80.

[0015] Furthermore, the mass ratio of the lipophilic emulsifier Span-80 and the hydrophilic emulsifier Tween-80 in the composite emulsifier in step (3) is (2-3):1.

[0016] Furthermore, in the step (1), the mass ratio of the Lewis acid to the boron fluoride mixture in the catalyst is 1:(1.5-2).

[0017] Furthermore, the mass ratio of the composite emulsifier in step (3) to the di(3-trimethoxysilylpropyl)amine in step (1) is 1:(2-3)

[0018] Furthermore, the prepared defoaming agent is used for treating oily wastewater in oilfield development.

[0019] According to the embodiments of the present invention, a defoamer for oilfield wastewater treatment and a preparation method thereof have the following advantages:

[0020] 1. Select di(3-trimethoxysilylpropyl)amine and chloroethanol, which are low in cost, good in stability and easily available as raw materials for polymerization, and form a mixed emulsion by mixing and stirring at room temperature under the catalysis of a mixture of Lewis acid and boron fluoride. The operation is simple and the cost is controllable.

[0021] 2. Before introducing ethylene oxide for reaction, introduce nitrogen to create an oxygen-free environment to enhance the safety of the reaction.

[0022] 3. The circulation of ethylene oxide greatly improves the utilization rate of ethylene oxide, the conversion rate of the reaction, and the economic efficiency of the reaction.

[0023] 4. By adding the optimal ratio of lipophilic and hydrophilic emulsifier composition, the surface tension is greatly reduced, the lubrication performance is improved, the raw material cost is low, and the preparation process is simple.

[0024] 5. The composite silicon-containing polyether surfactant of the present invention has good foam suppression and foam breaking effects when treating oilfield oily wastewater. The defoaming rate at a concentration of 5 mg / L is above 95% on average, and has good market application value. DETAILED DESCRIPTION

[0025] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] (1) adding 341 g of di(3-trimethoxysilylpropyl)amine, 34 g of a catalyst (13.6 g of Lewis acid, 27.2 g of boron fluoride), and 160 g of chloroethanol in a high temperature and high pressure reactor, mixing and stirring at room temperature for 30 minutes to form a mixed emulsion;

[0028] (2) introducing nitrogen, evacuating and replacing 2-3 times, heating to 80°C, circulating 440 g of ethylene oxide, continuing to raise the temperature to 125°C, stirring continuously, and keeping the temperature for reaction for 3 hours;

[0029] (3) Stop introducing ethylene oxide, introduce cold nitrogen to lower the temperature of the reactor to 40° C., add 114 g of a composite emulsifier (85.5 g of a lipophilic emulsifier Span-80 and 28.5 g of a hydrophilic emulsifier Tween-80), and continue stirring for 25 minutes to obtain a defoaming agent.

[0030] Example 2

[0031] (1) adding 341 g of di(3-trimethoxysilylpropyl)amine, 68 g of a catalyst (23 g of Lewis acid, 45 g of boron fluoride), and 240 g of chloroethanol in a high temperature and high pressure reactor, mixing and stirring at room temperature for 50 minutes to form a mixed emulsion;

[0032] (2) introducing nitrogen, evacuating and replacing 2-3 times, heating to 100°C, circulating 528 g of ethylene oxide, continuing to raise the temperature to 140°C, stirring continuously, and keeping the temperature for reaction for 2.5 hours;

[0033] (3) Stop introducing ethylene oxide, introduce cold nitrogen to lower the temperature of the reactor to 50° C., add 170 g of a composite emulsifier (100 g of a lipophilic emulsifier Span-80 and 70 g of a hydrophilic emulsifier Tween-80), and continue stirring for 30 minutes to obtain a defoaming agent.

[0034] Example 3

[0035] (1) adding 341 g of di(3-trimethoxysilylpropyl)amine, 68 g of a catalyst (23 g of Lewis acid, 45 g of boron fluoride), and 240 g of chloroethanol in a high temperature and high pressure reactor, mixing and stirring at room temperature for 60 minutes to form a mixed emulsion;

[0036] (2) introducing nitrogen, evacuating and replacing 2-3 times, heating to 90°C, circulating 440 g of ethylene oxide, continuing to raise the temperature to 120°C, stirring continuously, and keeping the temperature for reaction for 3 hours;

[0037] (3) Stop the introduction of ethylene oxide, introduce cold nitrogen to lower the temperature of the reactor to 44°C, add 170 g of composite emulsifier (100 g of lipophilic emulsifier Span-80 and 70 g of hydrophilic emulsifier Tween-80), continue stirring for 20 minutes, and obtain a defoamer. The conversion rate of the raw material of Example 1-3 bis(3-trimethoxysilylpropyl)amine is shown in Table 1.

[0038] Table 1 Conversion rate of di(3-trimethoxysilylpropyl)amine after reaction in step (3)

[0039]

[0040]

[0041] The control test of the present invention is to introduce ethylene oxide unidirectionally for polymerization reaction. Compared with the data of Examples 1-3 in which ethylene oxide is introduced cyclically, it can be seen that the cyclic introduction of ethylene oxide greatly improves the conversion rate of the raw material di(3-trimethoxysilylpropyl)amine and improves the economy of the reaction.

[0042] The test object is the oily wastewater after dehydration at a joint station of the Dingbian Oil Production Plant of Yanchang Oilfield in Shaanxi Province. The concentration of the defoamer is 5 mg / L. The test results are shown in Table 2.

[0043] Table 2 Defoaming test results statistics

[0044] Defoaming agent Defoaming rate Example 1 93％ Example 2 98％ Example 3 95％

[0045] It can be seen from the test results in Table 1 that the average defoaming rate of the defoaming agent of the present invention at a concentration of 5 mg / L is above 95%, and can reach up to 98%.

[0046] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A defoaming agent for oilfield wastewater treatment and a preparation method thereof, characterized in that: The preparation method comprises the following steps: (1) adding di(3-trimethoxysilylpropyl)amine, a catalyst, and haloethanol in a high temperature and high pressure reactor in sequence, and mixing and stirring at room temperature for 30-60 minutes to form a mixed emulsion; (2) introducing nitrogen, evacuating and replacing 2-3 times, raising the temperature to 80-100°C, circulating ethylene oxide, continuing to raise the temperature to 120-140°C, continuously stirring, and keeping the temperature for reaction for 2-3 hours; (3) Stop introducing ethylene oxide, introduce cold nitrogen to lower the temperature of the reactor to 40-50° C., add the composite emulsifier and continue stirring for 20-30 minutes to obtain a defoaming agent.

2. The defoaming agent for oilfield wastewater treatment and its preparation method according to claim 1, characterized in that: The molar ratio of di(3-trimethoxysilylpropyl)amine, haloethanol and ethylene oxide is 1:(2-3):(10-12).

3. The defoaming agent for oilfield wastewater treatment and its preparation method according to claim 1, characterized in that: The haloethanol in step (1) is chloroethanol.

4. The defoaming agent for oilfield wastewater treatment and the preparation method thereof according to claim 1, characterized in that: The catalyst in step (1) is a mixture of Lewis acid and boron fluoride.

5. The defoaming agent for oilfield wastewater treatment and its preparation method according to claim 1, characterized in that: The mass ratio of the catalyst to di(3-trimethoxysilylpropyl)amine is (0.1-0.2):

1.

6. The defoaming agent for oilfield wastewater treatment and the preparation method thereof according to claim 1, characterized in that: The composite emulsifier in step (3) is a mixture of a lipophilic emulsifier Span-80 and a hydrophilic emulsifier Tween-80.

7. The defoaming agent for oilfield wastewater treatment and the preparation method thereof according to claim 6, characterized in that: The mass ratio of the lipophilic emulsifier Span-80 and the hydrophilic emulsifier Tween-80 in the composite emulsifier is (2-3):

1.

8. The defoaming agent for oilfield wastewater treatment and its preparation method according to claim 4, characterized in that: The mass ratio of the Lewis acid and boron fluoride mixture in the catalyst of the step is 1:(1.5-2).

9. The defoaming agent for oilfield wastewater treatment and the preparation method thereof according to claim 1, characterized in that: The mass ratio of the composite emulsifier in step (3) to the di(3-trimethoxysilylpropyl)amine in step (1) is 1:(2-3).

10. The defoamer prepared according to any one of claims 1 to 9 is used for treating oily wastewater in oilfield development.

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