A polyether demulsifier and its synthesis method

Abstract

The invention belongs to the technical field of sewage treatment, and specifically relates to a polyether demulsifier and a synthesis method thereof. The synthesis method is as follows: add p-aminopyridine, toluene, and a catalyst in a high-pressure reactor in sequence, purge the reactor with nitrogen, and evacuate; introduce ethylene oxide and propylene oxide in sequence, heat, keep warm for reaction, cool, and stop the reaction to obtain a mixed solution; slowly stir the mixed solution, adjust the pH with hydrochloric acid, place it in a separating funnel, let it stand for stratification, discard the water phase, perform vacuum distillation on the toluene phase, discard the fraction below 100°C, and collect the fraction; add acetone and dodecyl bromide to the fraction, heat and reflux, cool to below 40°C, perform vacuum distillation, discard the evaporated acetone, and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product demulsifier. The demulsifier has the characteristics of simple synthesis process and high demulsification rate. When the concentration is 20 mg / L, the oil removal rate reaches more than 98%.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and specifically relates to a polyether demulsifier and a synthesis method thereof. Background Art

[0002] As oilfield development enters the middle and late stages, the water content of oil well produced fluids rises sharply, with the comprehensive water content exceeding 90%, and the comprehensive water content of some single well produced fluids reaching or even exceeding 95%. In order to improve crude oil recovery, major oilfields have implemented ASP technology in many blocks, which has significantly improved crude oil recovery. However, alkali, surfactants and polymers have also made the emulsification of oilfield produced water more and more serious, and the oil content in produced water has increased. It is necessary to demulsify the produced water to recover crude oil.

[0003] The proportion of oil-in-water (O / W) emulsions in oilfield produced fluids is increasing. O / W emulsions maintain a stable state through negative electrical repulsion between oil droplets and viscoelastic interfacial film protection. As the emulsification degree of O / W emulsions increases, the oil-water interface structure becomes more complex, and the demulsification process becomes increasingly difficult.

[0004] The main methods of demulsification are physical methods (such as coalescence degreasing, cyclone degreasing) and chemical methods. Among them, the treatment effect of physical methods is generally not ideal. The commonly used agent for chemical methods is demulsifier, which can be roughly divided into the following two categories: one category has diverse ingredients and good degreasing effect, but has the disadvantages of complex preparation and use process and high cost; the other category of degreasing agent has a single ingredient, simple preparation and use process, low cost, and low water quality requirements, but has the disadvantage of poor degreasing effect.

[0005] CN101113028A discloses a demulsifying purifier, characterized in that it is composed of the following raw materials in weight percentage: 2% to 68% of sewage clean, 2% to 37% of polyferric sulfate, 5% to 45% of polyaluminium chloride, 6% to 57% of anhydrous calcium chloride, and 19% to 47% of ferric chloride; its preparation method is: add sewage clean, polyferric sulfate and polyaluminium chloride into a mixer, then pour in anhydrous calcium chloride and add 50% of water of the sum of the four raw materials, stir fully, stir at a speed of 60 revolutions per minute, ensure that the solid components are completely dissolved, and keep for 2-3 hours; then add ferric chloride and continue stirring, stirring at a speed of 50-80 revolutions per minute, for 0.5-1 hour, stop for 6-10 hours, filter and pack into product packaging barrels. The invention has the advantages of good sewage treatment effect and small investment. The demulsifying purifier is used at a concentration of 300-500 mg / L. The dosage of the agent is very large during demulsification, which not only causes troublesome operation and increased costs, but also generates a large amount of scum and leaves a large amount of the agent in the water, causing secondary pollution.

[0006] CN104176788A discloses an oil remover for wastewater produced by binary composite flooding in oil fields and a preparation method thereof. The oil remover comprises acryloyloxyethyl dimethylamine, chloroalkane, acrylamide, N,N'-methylenebisacrylamide, ammonium persulfate and sodium sulfite. The preparation method of the oil remover is as follows: acryloyloxyethyl dimethylamine and chloroalkane (C n H 2n+1 Cl, n = 1 ~ 12) reaction to generate cationic monomers; acrylamide and N, N'-methylenebisacrylamide are mixed, added to deionized water three times, stirred while adding, and after complete dissolution, the prepared cationic monomers are added, and then ammonium persulfate and sodium sulfite solutions are added respectively, and the degreasing agent is obtained after stirring at a constant temperature of 45 ° C for 3h to 5h. The invention has the advantages of simple preparation, convenient use, small amount of reagents, low cost, high oil removal rate of more than 90%, and the recovered oil generated by separation does not affect the subsequent crude oil dehydration. Therefore, the present invention can be widely used in the oil removal process of binary composite flooding produced wastewater in oil fields. The field test of the degreasing agent has a reagent addition concentration of 60mg / L, and the oil content after treatment still remains 68.2mg / L, and the demulsification and oil removal efficiency needs to be improved. Summary of the invention

[0007] Aiming at the deficiencies of the current prior art, the present invention provides a polyether demulsifier and a synthesis method thereof. The demulsifier has the characteristics of simple synthesis process and high demulsification rate. When the use concentration is 20 mg / L, the oil removal rate reaches more than 98%.

[0008] In order to achieve the above object, one of the objects of the present invention discloses a polyether demulsifier, and the molecular formula of the polyether demulsifier is as follows:

[0009]

[0010] Where:

[0011] m is a positive integer of 2-20, more preferably a positive integer of 5-10;

[0012] n is a positive integer of 2-20, more preferably a positive integer of 10-20;

[0013] x is a positive integer of 5-50, more preferably a positive integer of 20-30;

[0014] y is a positive integer of 5-50, more preferably a positive integer of 10-20.

[0015] Another object of the present invention is to provide a method for synthesizing a polyether demulsifier, and the synthesis method is as follows:

[0016] (1) adding p-aminopyridine, toluene, and a catalyst to a high-pressure reactor in sequence, purging the reactor with nitrogen, and evacuating the reactor; introducing ethylene oxide and propylene oxide in sequence, heating, keeping the temperature for reaction, cooling to below 40° C., stopping the reaction, and obtaining a mixed solution;

[0017] (2) The mixed solution was slowly stirred, and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel, allowed to stand for stratification, the aqueous phase was discarded, the toluene phase was subjected to reduced pressure distillation, the fraction below 100° C. was discarded, and the fraction between 100° C. and 220° C. was collected;

[0018] (3) Add acetone and dodecyl bromide to the fraction between 100 and 220°C, heat to reflux, cool to below 40°C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with an equal weight of methanol to obtain the product demulsifier.

[0019] In the present invention, preferably, the molar ratio of ethylene oxide, propylene oxide, dodecyl bromide and p-aminopyridine is 10-100:4-40:0.7-1.1:1; more preferably, the molar ratio of ethylene oxide, propylene oxide, dodecyl bromide and p-aminopyridine is 20-50:10-20:0.8-1.05:1.

[0020] In the present invention, preferably, the mass ratio of toluene to p-aminopyridine in step (1) is 3-6:1.

[0021] Preferably, the catalyst in step (1) is one of sodium hydroxide, potassium hydroxide and calcium acetate, and the mass ratio of the catalyst to p-aminopyridine is 0.01-0.05:1.

[0022] Preferably, the heating temperature in step (1) is 120-180° C., and the insulation reaction time is 1-6 h; more preferably, the heating temperature is 130-150° C., and the insulation reaction time is 2-5 h.

[0023] In the present invention, preferably, the mass ratio of acetone to p-aminopyridine in step (3) is 15-20:1.

[0024] Preferably, the heating reflux time in step (3) is 12-48 h; more preferably, the heating reflux time is 24-36 h.

[0025] The reaction equation of the polyether demulsifier of the present invention is:

[0026]

[0027]

[0028] The polyether demulsifier of the present invention is a mixed type of cationic and nonionic surfactant, wherein the cation is a tertiary amine and a quaternary ammonium on a pyridine ring, and the nonionic is a hetero-embedded polyether. The surfactant lipophilic group is a dodecyl group and a dipolyoxypropyl ether segment, and the hydrophilic group is a pyridine ring and a dipolyoxyethyl ether segment. Most of the crude oil in the emulsion is tiny oil droplets, the surface of the oil droplets is negatively charged and very stable, the cationic group can neutralize the negative charge of the interface film of the emulsified oil droplets, compress and destroy the double electric layer, weaken the strength of the interface film, and make the emulsified droplets collide and coalesce, the tertiary amine can neutralize the negatively charged oil droplets, so that the oil droplets lose the repulsive effect and gather together, so that the tiny oil droplets gather and release to form oil droplets with large particle size, thereby achieving the purpose of demulsification; the molecule of the present invention can enter the oil-water interface, replace the surfactant with strong emulsification, displace the surfactant molecules and other surface active substances, destroy the emulsification ability of the oil droplets, and make it easier for the small oil droplets to approach and condense; the hetero-embedded polyether segment in the molecule of the present invention has high flexibility, it is easy to cause the internal rotation of the molecular chain, and can capture a large number of tiny oil droplets, increase the chance of oil droplet collision, and form oil droplets that are easy to coalesce and float to achieve the purpose of demulsification.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] (1) The raw materials of the polyether demulsifier of the present invention are cheap, easy to obtain, widely available, and have a simple synthesis process;

[0031] (2) The polyether demulsifier of the present invention has a good demulsification effect. When the concentration is 20 mg / L, the oil removal rate reaches more than 98%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is an infrared spectrum characterization diagram of the polyether demulsifier M8, a product of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with specific examples and with reference to data. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0034] Example 1

[0035] (1) 0.5 mol of p-aminopyridine, 282 g of toluene, and 0.47 g of sodium hydroxide were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 5 mol of ethylene oxide and 2 mol of propylene oxide were introduced in sequence, and the reaction was heated to 120° C. and kept at this temperature for 1 hour, and then the temperature was lowered to below 40° C. to stop the reaction.

[0036] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0037] (3) Add 705 g of acetone and 0.35 mol of dodecyl bromide to the fraction between 100 and 220 °C, heat and reflux for 12 h, cool to below 40 °C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M1.

[0038] Example 2

[0039] (1) 0.5 mol of p-aminopyridine, 250 g of toluene, and 0.68 g of sodium hydroxide were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 10 mol of ethylene oxide and 4 mol of propylene oxide were introduced in sequence, and the reaction was heated to 130° C. and kept at this temperature for 1.5 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0040] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0041] (3) Add 730 g of acetone and 0.4 mol of dodecyl bromide to the fraction between 100 and 220 °C, heat and reflux for 12 h, cool to below 40 °C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M2.

[0042] Example 3

[0043] (1) 0.5 mol of p-aminopyridine, 222 g of toluene, and 0.99 g of sodium hydroxide were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 15 mol of ethylene oxide and 8 mol of propylene oxide were introduced in sequence, and the reaction was heated to 140° C. and kept at this temperature for 2 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0044] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0045] (3) Add 768 g of acetone and 0.55 mol of dodecyl bromide to the fraction between 100 and 220 °C, heat and reflux for 16 h, cool to below 40 °C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M3.

[0046] Example 4

[0047] (1) 0.5 mol of p-aminopyridine, 198 g of toluene, and 1.33 g of sodium hydroxide were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 20 mol of ethylene oxide and 15 mol of propylene oxide were introduced in sequence, and the reaction was heated to 140° C. and kept at this temperature for 3 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0048] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0049] (3) Add 816 g of acetone and 0.52 mol of dodecyl bromide to the fraction at 100-220°C, heat and reflux for 16 h, cool to below 40°C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M4.

[0050] Example 5

[0051] (1) 0.5 mol of p-aminopyridine, 188 g of toluene, and 1.78 g of potassium hydroxide were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 30 mol of ethylene oxide and 15 mol of propylene oxide were introduced in sequence, and the reaction was heated to 150° C. and kept at this temperature for 4 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0052] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0053] (3) Add 848 g of acetone and 0.44 mol of dodecyl bromide to the fraction at 100-220°C, heat and reflux for 24 h, cool to below 40°C, and distill under reduced pressure. Discard the acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M5.

[0054] Example 6

[0055] (1) 0.5 mol of p-aminopyridine, 162 g of toluene, and 2.1 g of potassium hydroxide were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 40 mol of ethylene oxide and 12 mol of propylene oxide were introduced in sequence, and the reaction was heated to 160° C. and kept at this temperature for 5 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0056] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0057] (3) Add 886 g of acetone and 0.5 mol of dodecyl bromide to the fraction at 100-220°C, heat and reflux for 24 h, cool to below 40°C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M6.

[0058] Example 7

[0059] (1) 0.5 mol of p-aminopyridine, 144 g of toluene, and 2.2 g of calcium acetate were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 45 mol of ethylene oxide and 12 mol of propylene oxide were introduced in sequence, and the reaction was heated to 180° C. and kept at this temperature for 6 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0060] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0061] (3) Add 904 g of acetone and 0.46 mol of dodecyl bromide to the fraction at 100-220°C, heat and reflux for 36 h, cool to below 40°C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M7.

[0062] Example 8

[0063] (1) 0.5 mol of p-aminopyridine, 141 g of toluene, and 2.35 g of calcium acetate were added to a high-pressure reactor in sequence, and the reactor was purged with nitrogen and evacuated; 50 mol of ethylene oxide and 20 mol of propylene oxide were introduced in sequence, and the reaction was heated to 180° C. and kept at this temperature for 6 h. The reaction was then stopped after the temperature was lowered to below 40° C.

[0064] (2) The mixed solution was slowly stirred and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel and allowed to stand for separation. The aqueous phase was discarded and the toluene phase was subjected to reduced pressure distillation. The fraction below 100° C. was discarded and the fraction between 100° C. and 220° C. was collected.

[0065] (3) Add 940 g of acetone and 0.48 mol of dodecyl bromide to the fraction at 100-220°C, heat and reflux for 48 h, cool to below 40°C, and distill under reduced pressure. Discard the distilled acetone and dissolve the remaining viscous liquid with the same weight of methanol to obtain the product polyether demulsifier M8.

[0066] Example 9 Demulsifier Evaluation

[0067] Demulsification experiments were conducted on produced water after oil-water separation at a certain oilfield joint station using the demulsifier of the present invention at different concentrations. The experimental method was based on SY / T5797-1993 "Method for evaluating the performance of demulsifiers for oil-in-water emulsions".

[0068] Properties of produced water: oil content, 867 mg / L; temperature, 68°C; mineralization, 24300 mg / L.

[0069] Demulsifier concentration: 5, 10, 15, 20 mg / L.

[0070] Comparative demulsifier: BP-169.

[0071] The experimental results are shown in Table 1.

[0072] Table 1 Demulsifier demulsification test results (oil removal rate, %)

[0073]

[0074]

[0075] From Table 1 we can see that:

[0076] (1) The oil removal rate of the polyether demulsifiers M1-M8 of the present invention reached 80% or more when the concentration was 5 mg / L, and the highest reached 93.2%; while the oil removal rate of BP-169 was 72.6% when the concentration was 5 mg / L;

[0077] (2) The oil removal rate of the polyether demulsifiers M1-M8 of the present invention reached 90% or more when the concentration was 10 mg / L, and the highest reached 98%; while the oil removal rate of BP-169 was 82.6% when the concentration was 10 mg / L;

[0078] (3) The oil removal rate of the polyether demulsifiers M1-M8 of the present invention reached 95% or more when the concentration was 15 mg / L, and the highest reached 99.1%; while the oil removal rate of BP-169 was 92.0% when the concentration was 15 mg / L;

[0079] (4) The oil removal rate of the polyether demulsifiers M1-M8 of the present invention reaches 98% or more when the concentration is 20 mg / L, and the highest reaches 99.4%; while the oil removal rate of BP-169 is 93.5% when the concentration is 20 mg / L. Compared with the prior art products, the demulsifier of the present invention has a good oil removal effect.

[0080] Example 10 Demulsifier Field Application

[0081] A field test was conducted at a water injection station. The treatment object was ASP flooding produced water, which had an oil content of 1800 mg / L, a mineralization of 13000 mg / L, and a temperature of 72°C. The test treatment scale was 75m 3 The demulsifier N8 of the present invention was used to demulsify the produced water. The dosage of the demulsifier N8 was 1.5 kg / d and the concentration was 20 mg / L. After the treatment, the oil content of the produced water was reduced to 8 mg / L, and the oil removal rate reached 99.5%, meeting the process requirements.

[0082] Example 11 Infrared spectroscopy characterization

[0083] The product M8 was characterized by infrared spectroscopy. Figure 1 shown.

[0084] Figure 1 Medium, 2935cm -1 It is the absorption peak of the CH bond in dodecyl; 1408cm -1 It is the absorption peak of polyoxypropylene ether; 1066cm -1 It is the absorption peak of polyoxyethylene segment; 890cm -1 It is the CN stretching vibration absorption peak.

[0085] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for synthesizing a polyether demulsifier, characterized in that: The synthetic method is as follows: (1) adding p-aminopyridine, toluene, and a catalyst to a high-pressure reactor in sequence, purging the reactor with nitrogen, and evacuating the reactor; introducing ethylene oxide and propylene oxide in sequence, heating, keeping the temperature for reaction, cooling to below 40° C., stopping the reaction, and obtaining a mixed solution; (2) The mixed solution was slowly stirred, and the pH was adjusted to 7-9 with hydrochloric acid. The mixture was placed in a separatory funnel, allowed to stand for stratification, the aqueous phase was discarded, the toluene phase was subjected to reduced pressure distillation, the fraction below 100° C. was discarded, and the fraction between 100° C. and 220° C. was collected; (3) adding acetone and dodecyl bromide to the fraction between 100° C. and 220° C., heating to reflux, cooling to below 40° C., distilling under reduced pressure, discarding the distilled acetone, and dissolving the remaining viscous liquid with an equal weight of methanol to obtain the product demulsifier; The catalyst in step (1) is one of sodium hydroxide, potassium hydroxide and calcium acetate, and the mass ratio of the catalyst to p-aminopyridine is 0.01-0.05:

1.

2. A method for synthesizing a polyether demulsifier as claimed in claim 1, characterized in that: The molar ratio of ethylene oxide, propylene oxide, dodecyl bromide and p-aminopyridine is 10-100:4-40:0.7-1.1:

1.

3. A method for synthesizing a polyether demulsifier as claimed in claim 1, characterized in that: The heating temperature in step (1) is 120-180° C., and the insulation reaction time is 1-6 hours.

4. A method for synthesizing a polyether demulsifier as claimed in claim 3, characterized in that: The heating temperature is 130-150° C., and the heat preservation reaction time is 2-5 hours.

5. A method for synthesizing a polyether demulsifier as claimed in claim 1, characterized in that: The mass ratio of acetone to aminopyridine in step (3) is 15-20:

1.

6. A method for synthesizing a polyether demulsifier as claimed in claim 1, characterized in that: The heating reflux time in step (3) is 12-48h.

7. A method for synthesizing a polyether demulsifier as claimed in claim 6, characterized in that: The heating reflux time is 24-36h.

8. A polyether demulsifier, characterized in that: The molecular formula of the polyether demulsifier is as follows: Where: m is a positive integer from 2 to 20; n is a positive integer from 2 to 20; x is a positive integer between 5 and 50; y is a positive integer ranging from 5 to 50.

9. A polyether demulsifier as claimed in claim 8, characterized in that: The m is a positive integer of 5-10, n is a positive integer of 10-20, x is a positive integer of 20-30, and y is a positive integer of 10-20.

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