A polystyrene-polyether core-shell structure demulsifier and a preparation method thereof

Abstract

The application discloses a polystyrene-polyether core-shell structure demulsifier and a preparation method thereof, relates to the technical field of oil fields, and comprises the following steps: adding nano polystyrene microspheres, p-chlorobenzaldehyde and aluminum tribromide into ethanol, stirring and reacting, filtering, washing, and drying to obtain modified nano polystyrene microspheres; and adding the modified nano polystyrene microspheres and polyether monoamine into ethanol, stirring and reacting at room temperature for 12 hours, filtering, washing, and drying to obtain the polystyrene-polyether core-shell structure demulsifier. Compared with existing polyether demulsifiers, the polystyrene-polyether core-shell structure demulsifier has a faster demulsification and dehydration rate and a higher dehydration rate, and has better demulsification and dehydration performance for thick oil crude oil emulsion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemistry, in particular to a polystyrene-polyether core-shell structure demulsifier and a preparation method thereof. BACKGROUND

[0002] Bohai oilfield is the world's largest offshore heavy oil field, with 58% of heavy oil production. Heavy oil plays a dominant role in offshore oil development and has become an important pillar of national oil supply. Produced liquid treatment is the "last mile" of green, safe and sustainable development and production landing in oilfields, and is the "link" of production realization and sales benefit. Offshore platform produced liquid treatment has become a major "bottleneck" technical problem for the sustained production of offshore oil industry, especially the treatment of heavy oil produced liquid. Among them, the demulsification and dehydration of heavy oil emulsion (generally referred to as W / O emulsion) is the key to the treatment of heavy oil produced liquid, and a high-efficiency demulsifier usually needs to be developed. Block polyether is the most commonly used demulsifier in offshore oilfields at present. In order to improve its demulsification performance, its structure can be changed by chain extension, branching and other means to improve its performance. The common chain extension method is to use toluene diisocyanate as a chain extender, and the isocyanate group reacts with the hydroxyl group of polyether to extend the chain. The common branching method is to use a resin containing multiple active hydrogens as a starting agent to ring-opening polymerize ethylene oxide and propylene oxide. However, conventional demulsifiers also have some shortcomings and deficiencies in actual application. First, the demulsification efficiency of these demulsifiers is greatly affected by environmental factors, especially in offshore oilfields, because the temperature, salinity and pressure fluctuate sharply, the effect of the demulsifier is often difficult to maintain stable. Second, when treating heavy oil emulsion, conventional demulsifiers can cause the treated emulsion to be re-emulsified, forming a secondary emulsion, which not only increases the complexity of the treatment, but also can cause secondary pollution. Third, most conventional demulsifiers do not have ideal effects in high-concentration heavy oil emulsion, resulting in a slow demulsification process and often requiring a high dosage, thereby increasing the operating cost. In addition, these demulsifiers usually lack sufficient selectivity, which can also demulsify other non-target substances, thereby affecting the treatment efficiency and even shortening the service life of the equipment. Therefore, it is urgent to develop more efficient and more adaptable demulsifiers, especially for specific conditions in offshore oilfields. SUMMARY

[0003] In view of this, the present application provides a polystyrene-polyether core-shell structure demulsifier and a preparation method thereof, which can realize rapid and complete stable demulsification compared with existing demulsifiers.

[0004] The present application discloses a polystyrene-polyether core-shell structure demulsifier and a preparation method thereof, which comprises the following steps:

[0005] Step S1: nano polystyrene microspheres, p-chlorobenzaldehyde, aluminum tribromide are added into ethanol to stir and react, then filtered, washed, and dried to obtain surface-modified nano polystyrene microspheres;

[0006] Step S2: the surface-modified nano polystyrene microspheres and polyether monoamine are added into ethanol to stir and react at room temperature for 11-13 hours, then filtered, washed, and dried.

[0007] In an embodiment of the present application, the nano polystyrene microspheres in step S1 have a particle size of 20-30 nm.

[0008] In an embodiment of the present application, the concentration of the nano polystyrene microspheres in ethanol in step S1 is 5 g / 100 mL.

[0009] In an embodiment of the present application, the concentration of p-chlorobenzaldehyde in ethanol in step S1 is 0.1-0.5 mol / L.

[0010] In an embodiment of the present application, the molar ratio of aluminum tribromide to p-chlorobenzaldehyde in step S1 is 1:4-8.

[0011] In an embodiment of the present application, the stirring and reaction in step S1 is carried out at 30-60℃ for 5-8 hours.

[0012] In an embodiment of the present application, the concentration of the surface-modified nano polystyrene microspheres in ethanol in step S2 is 5 g / 100 mL.

[0013] In an embodiment of the present application, the polyether monoamine in step S2 is one of M-1000, M-2005, M-2070, and M3085.

[0014] In an embodiment of the present application, the molar ratio of the aldehyde groups on the surface of the surface-modified nano polystyrene microspheres to the polyether monoamine in step S2 is 1:0.3-0.6.

[0015] and the polystyrene-polyether core-shell structure demulsifier prepared by the above method.

[0016] The present application has the following technical effects:

[0017] The polystyrene-polyether core-shell structure demulsifier disclosed in the present application has a faster demulsification and dehydration rate and a higher dehydration rate than existing polyether demulsifiers, and has more thorough demulsification effect, stronger stability, and more excellent demulsification and dehydration performance for thick oil crude oil emulsion, and has good selectivity. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1The infrared spectrum of the polystyrene-polyether core-shell structure demulsifier in Example 1 of the present application is shown in the following figure.

[0019] Figure 2 The scanning electron microscope (SEM) observation result of the polystyrene-polyether core-shell structure demulsifier in Example 1 of the present application is shown in the following figure. DETAILED DESCRIPTION

[0020] The present application will be further described in detail below with reference to examples, but the embodiments of the present application are not limited thereto, wherein the experimental methods used in the following examples are conventional methods unless otherwise specified; and the materials, reagents and the like used therein are commercially available unless otherwise specified.

[0021] Example 1

[0022] (1) 5 g of polystyrene microspheres with a particle size of 20-30 nm (denoted as m1), 5.62 g (0.04 mol) of p-chlorobenzaldehyde, and 1.78 g (0.0067 mol) of aluminum tribromide were added into 100 mL of ethanol, and after stirring and reacting at 40°C for 8 h, filtration, ethanol washing, and drying were performed to obtain modified nanometer polystyrene microspheres with aldehyde groups on the surface (denoted as m2).

[0023] (2) 5 g of the modified nanometer polystyrene microspheres with aldehyde groups on the surface obtained in step (1) and 7.5 g of polyether monoamine M-2005 (0.00375 mol) were added into 100 mL of ethanol, wherein the aldehyde groups on the surface of the modified polystyrene microspheres were 0.0075 mol, and after stirring and reacting at room temperature for 12 h, filtration, ethanol washing, and drying were performed to obtain a polystyrene-polyether core-shell structure demulsifier.

[0024] Example 2

[0025] The embodiment of the present example is basically the same as that of Example 1, and the aldehyde groups on the surface of the modified polystyrene microspheres are 0.0075 mol, and the difference lies in that 3.75 g of M-1000 is added in (2).

[0026] Example 3

[0027] The embodiment of the present example is basically the same as that of Example 1, and the aldehyde groups on the surface of the modified polystyrene microspheres are 0.0075 mol, and the difference lies in that 7.5 g of M-2070 is added in (2).

[0028] Example 4

[0029] The embodiment of the present example is basically the same as that of Example 1, and the aldehyde groups on the surface of the modified polystyrene microspheres are 0.0075 mol, and the difference lies in that 11.25 g of M-3085 is added in (2).

[0030] Example 5

[0031] The embodiment of the present example is basically the same as that of Example 1, except that the aldehyde group on the surface of the modified polystyrene microspheres is 0.0075 mol, and the mass of the polyether monoamine M-2005 added in (2) is 4.5 g.

[0032] Example 6

[0033] The embodiment of the present example is basically the same as that of Example 1, except that the aldehyde group on the surface of the modified polystyrene microspheres is 0.0075 mol, and the mass of the polyether monoamine M-2005 added in (2) is 6 g.

[0034] Example 7

[0035] The embodiment of the present example is basically the same as that of Example 1, except that the aldehyde group on the surface of the modified polystyrene microspheres is 0.0075 mol, and the mass of the polyether monoamine M-2005 added in (2) is 9 g.

[0036] In the above examples, the calculation method of the mass molar concentration b (mmol / g) of the aldehyde group polystyrene on the surface of the microspheres is shown in formula (1):

[0037] b = [(m2-m1) / M x m2] x 1000 (1)

[0038] In formula (1), m2 is the mass of the polystyrene microspheres after the reaction of step S1, g; m1 is the mass of the polystyrene microspheres before the reaction of step S1, g; M is the molecular weight of p-chlorobenzaldehyde, g / mol.

[0039] To better illustrate the technical effects of the present application, the following related examples are provided with corresponding characterization and performance evaluation.

[0040] I. Infrared characterization

[0041] The polystyrene-polyether core-shell structure demulsifier prepared in Example 1 was subjected to infrared characterization, and the results are shown in Figure 1 It can be seen that, Figure 1 3308.03 cm -1 , 1626.90 cm -1 , 1550.34 cm -1 are the characteristic absorption peaks of styrene structural units, and 1102.08 cm -1 is the characteristic absorption peak of polyether, and the obtained substance is determined to have polystyrene and polyether structural groups.

[0042] II. Micro-morphology characterization

[0043] The polystyrene-polyether core-shell structure demulsifier in Example 1 was characterized by SEM, and the results are shown in Figure 1. Figure 2 As can be seen from Figure 1, the polystyrene-polyether core-shell structure demulsifier is spherical, and the particle size is still in the range of 20-30 nm, which proves that the spherical demulsifier with polystyrene-polyether core-shell structure is indeed prepared. Figure 2

[0044] III. Demulsification performance test

[0045] (1) Comparison of performance of core-shell structure demulsifier and other demulsifiers

[0046] The polystyrene-polyether core-shell structure demulsifiers prepared in Examples 1-4 were compared with common demulsifiers on the market in terms of demulsification performance. The steps of the demulsification experiment are as follows:

[0047] 1) 50 g of crude oil (taken from a production platform in Bohai oilfield, density at room temperature is 0.9635 g / cm 3 ) and 50 g of salt water (1 wt% NaCl aqueous solution) were preheated at 80°C for 30 min. The stirrer was started, and the salt water solution was gradually added to the crude oil at a stirring speed of 550 rpm. After the addition of the polymer solution was completed, the stirring was continued for 15 min to obtain a stable W / O crude oil emulsion.

[0048] 2) The emulsion prepared above was quickly transferred to a dehydration bottle, and the demulsifier (100 mg / L) was added to the dehydration bottle. After the emulsion was shaken by hand for 200 times, the emulsion was placed in a water bath at 80°C for incubation. The volume of water in the dehydration bottle at 30 min was recorded, and the dehydration rate was calculated. The specific results are shown in Table 1:

[0049] Table 5 Comparison of performance of demulsifiers

[0050]

[0051] (Demulsifier 5010, demulsifier 2410, demulsifier 2409, and demulsifier 2403 in Table 1 were purchased from Hebei Shengtian Chemical Co., Ltd.)

[0052] As can be seen from Table 1, the polystyrene-polyether core-shell structure demulsifier of the present application has a more excellent demulsification performance compared with the modified polyether amine and the four thick oil demulsifiers on the market.

[0053] (2) Effect of surface aldehyde group content of core-shell structure demulsifier on demulsification performance

[0054] Example 1 and Examples 5-7 were subjected to demulsification experiments in the same way as (1), and the experimental results are shown in Table 2:

[0055] ​Table 2 Influence of molar ratio of polyether monoamine to aldehyde group on surface of modified polystyrene microspheres on performance of core-shell demulsifier

[0056]

[0057] From Table 2, when the molar ratio of aldehyde group on surface of modified polystyrene microspheres to polyether monoamine is in the range of 1:0.3-0.6, the 30 min dehydration rate of the core-shell demulsifier can be controlled at above 90%, which proves that the polystyrene-polyether core-shell structure demulsifier disclosed in the application has excellent demulsification performance.

[0058] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the embodiments of the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be the protection scope of the claims.

Claims

1. A method for preparing a polystyrene-polyether core-shell structure demulsifier, characterized in that, Includes the following steps: Step S1: Add nano-polystyrene microspheres, p-chlorobenzaldehyde, and aluminum tribromide to ethanol, stir and react, then filter, wash, and dry to obtain modified nano-polystyrene microspheres; Step S2: Add the modified polystyrene nanospheres and polyether monoamine to ethanol and stir at room temperature for 11-13 hours. Then filter, wash and dry to obtain the product. The polyether monoamine is one of M-1000, M-2005, M-2070 and M-3085.

2. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: The nano-polystyrene microspheres mentioned in step S1 have a particle size of 20~30nm.

3. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: The concentration of the nano-polystyrene microspheres in ethanol in step S1 is 5 g / 100 mL.

4. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: In step S1, the concentration of p-chlorobenzaldehyde in ethanol is 0.1~0.5 mol / L.

5. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: In molar ratio, the ratio of aluminum tribromide to p-chlorobenzaldehyde in step S1 is 1:4~8.

6. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: The conditions for the stirring reaction in step S1 are: stirring at 30~60℃ for 5~8 hours.

7. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: The concentration of the modified polystyrene nanospheres in ethanol in step S2 is 5 g / 100 mL.

8. The method for preparing a polystyrene-polyether core-shell structure demulsifier according to claim 1, characterized in that: In molar ratio, the ratio of aldehyde groups to polyether monoamines on the surface of the modified polystyrene nanospheres in step S2 is 1:0.3~0.

6.

9. A polystyrene-polyether core-shell structure demulsifier, characterized in that, Prepared using the method described in any one of claims 1 to 8.

Images