Preparation method of modified biomass demulsifier, demulsifier and application

Abstract

The application discloses a preparation method of a modified biomass demulsifier, the demulsifier and application, and regenerates cellulose oligomers by hydrolyzing cotton through phosphoric acid, and then directly hydrothermally treating the cellulose oligomers through amino chemicals to prepare an aminated demulsifier. The application of the aminated demulsifier in oily wastewater is that the water phase transmittance of the oily wastewater after demulsification is above 86%, and the oil removal rate is as high as 99%. The demulsifier provided by the application has the characteristics of cheap and easily available raw materials, small demulsifier dosage, high demulsification efficiency, short demulsification time, biomass waste recycling, no pollution, easy degradation and simple preparation method, good adaptability, and good application and promotion prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of demulsifiers in the oil and gas industry, and particularly relates to a preparation method of an amino-biomass demulsifier, the demulsifier and application. BACKGROUND

[0002] In the oil and gas industry, oil-water mixed emulsion is a difficult problem to be solved in oil and gas exploration, oil production, oilfield water transportation and treatment and refining. First, in the drilling process, the additives added in the drilling fluid have emulsifying effect on mixed diesel oil, grease and the like, resulting in high oil content of the drilling waste liquid, affecting treatment and reuse and discharge; second, due to the lipophilic characteristics of natural surfactants in crude oil, the crude oil emulsion is formed with water; third, the active agent in the fracturing fluid is emulsified with crude oil or the oil displacement agent in the chemical oil displacement is emulsified with crude oil, and the adsorption of the oil / water interface has a great influence on the delay or inhibition of the leakage of the sedimentation film. The active agent is often adsorbed on the interface, which will inhibit or delay the precipitation of the film, resulting in difficulty in separation of oil and water, affecting subsequent treatment, transportation and processing and the like. Therefore, demulsification is crucial in the oil and gas industry. The emulsion decomposition method can be divided into three categories, namely, mechanical, electrical and chemical. In practice, the combination of mechanical and chemical, or electrical and chemical is the best choice. The most widely used technologies include heating and adding demulsifiers.

[0003] Chemical demulsifiers are amphiphilic compounds with both hydrophilic and hydrophobic properties, which can be adsorbed on the oil / water interface. Demulsifiers usually exhibit similar behavior to emulsifiers, but can replace stabilizers in the water and oil phases, causing droplets to coalesce. In order to break the stable oil / water interface around the emulsified water droplets, chemical demulsifiers usually need to have stronger surface activity than natural emulsion stabilizers. Notable chemical demulsifiers are divided into polymeric surfactants, nanoparticles and ionic liquids. For example, ethylene oxide-propylene oxide (EO-PO) block copolymers, silicon polyether, dendritic polymers, biodegradable polymer surfactants, ionic liquids and nanoparticle-based demulsifiers have attracted more and more attention in the industry. However, these demulsifiers have some inherent problems, such as complex and dangerous preparation process, high cost of raw materials, certain pollution to the environment, serious waste of resources and the like.

[0004] Chinese patent document with publication number CN105384927A and publication date of March 9, 2016 discloses an oil-in-water emulsion demulsifier and a preparation method thereof. The oil-in-water emulsion demulsifier is prepared by sequentially preparing a bisamide, a chlorinated polyether, and a cationic polyether. The preparation method comprises the following steps: 1) mixing an organic amine and a fatty acid in a molar ratio of 1:2-1:4 under stirring, controlling the temperature of the reaction system at 50-170 DEG C, and reacting for 3-18 h to obtain the bisamide; 2) sequentially adding an organic solvent ethanol and the bisamide into a four-necked flask provided with a thermometer, a stirrer, and a condenser, starting to drop polyepichlorohydrin at 20-120 DEG C, stirring for 5 h, and cooling to obtain the chlorinated polyether which is a brownish red viscous liquid; and 3) placing the chlorinated polyether and a dimethylamine aqueous solution synthesized above into a clean reaction kettle, purging air by introducing nitrogen, controlling the temperature at 50-80 DEG C, reacting for 5 h, continuously heating to 120 DEG C, and reacting for 6 h to obtain a brownish cationic polyether which is a water-soluble oil-in-water emulsion demulsifier. Although the organic demulsifier prepared by the method has high efficiency, the demulsifier remains in the oil phase or the water phase after demulsification, causing corresponding environmental problems.

[0005] Chinese patent document with publication number CN106219669A and publication date of December 14, 2016 discloses a preparation method of a magnetic graphene oxide demulsifier. The magnetic graphene oxide demulsifier is prepared by loading graphene oxide on the surface of magnetic iron powder as a carrier. The amount ratio of the ferromagnetic powder, ethanol, water, silane coupling agent, and graphene oxide is 1-5 g: 70-95 mL: 5-30 mL: 0.2-1 g: 1-5 g. The method loads graphene oxide on the surface of the magnetic iron powder as a carrier to prepare the demulsifier which can be reused. The magnetic iron powder modified graphene oxide demulsifier mentioned in the above patent has the advantages of recyclability, but still has many problems such as complex process and high raw material cost. Therefore, it still faces great challenges to seek a new demulsifier with wide sources, low cost, and excellent performance. SUMMARY

[0006] The present application aims at the defects and deficiencies of the prior art, and provides a preparation method of a modified biomass demulsifier. The method can effectively solve the technical problems of high raw material cost, narrow source selection range, and poor performance of the demulsifier in the prior art.

[0007] Another object of the present application is to provide a demulsifier prepared by the preparation method.

[0008] Still another object of the present application is to provide an application of the prepared demulsifier.

[0009] The present application is achieved by adopting the following technical solutions:

[0010] The application discloses a preparation method of a modified biomass demulsifier, and belongs to the technical field of demulsifiers.

[0011] The preparation method specifically comprises the following steps: adding cotton into phosphoric acid, dissolving sufficiently, and then stirring at 40-70 DEG C for 1-3 hours; adding ethanol to regenerate the dissolved cellulose and obtain cellulose oligomers; adding the cellulose oligomers into an aqueous solution of an amino compound, stirring uniformly, and then transferring into a polytetrafluoroethylene reaction kettle, and then hydrothermally obtaining the amino demulsifier.

[0012] Further, the cotton is natural cotton.

[0013] Further, the cotton is a product taking cotton as a raw material.

[0014] Further, the mass ratio of the cotton to the phosphoric acid is 1-5:100.

[0015] Further, the mass ratio of the cellulose oligomers to the aqueous solution of the amino compound is 2:40-50.

[0016] Further, the amino compound is at least one of ammonia, urea, ammonium bicarbonate and ethylenediamine.

[0017] The amino demulsifier is prepared by the preparation method of the modified biomass demulsifier.

[0018] The application of the amino demulsifier in oil-containing wastewater emulsion.

[0019] Further, the application comprises the following steps: dispersing the amino demulsifier in water to obtain a suspension, and then mixing the suspension with the oil-containing wastewater emulsion at room temperature and standing for 10-30 minutes.

[0020] After the demulsification, most of the amino demulsifier adsorbs oil and then floats on water together with the separated oil phase, and a small part of the amino demulsifier is deposited in water, and can be separated by long-time sedimentation or centrifugal separation, and the separation is relatively simple.

[0021] Further, the addition amount of the amino demulsifier in the oil-containing wastewater is 25-150 mg / L.

[0022] Further, the addition amount of the amino demulsifier in the oil-containing wastewater is 75-100 mg / L.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] 1. The preparation method uses cotton as a precursor to obtain an aminated demulsifier, the aminated demulsifier has a large number of active amino groups on the surface, and exhibits high interfacial activity, can quickly reduce the interfacial tension, and induce demulsification.

[0025] 2. The raw materials can be directly obtained from natural cotton or through waste cotton fabrics, can interact with asphaltene after modification, and are positively charged in the emulsion after modification to neutralize the electrostatic oil droplets with negative charge and promote demulsification. The application fully utilizes natural biomass, reduces the use of fossil raw materials, can be degraded in the natural environment, and has good application prospect.

[0026] 3. The aminated demulsifier provided by the application can realize normal temperature demulsification of oil-containing emulsion, realize effective separation of oil-water, and has the characteristics of small dosage and high demulsification efficiency. The oil removal rate of 75mg / L of the demulsifier under normal temperature conditions for 30min can reach 99.20%. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The scanning electron microscope image of the aminated demulsifier described in Example 4. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application, and are not used to limit the application.

[0029] The cotton used in the examples is natural cotton. The crude oil used in the examples is from Tarim Oilfield.

[0030] Example 1

[0031] As a preferred embodiment of the application, a preparation method of a modified biomass demulsifier is disclosed, which regenerates cellulose oligomers by hydrolyzing cotton with phosphoric acid, and then directly hydrothermally prepares an aminated demulsifier from the cellulose oligomers and an amino compound.

[0032] Example 2

[0033] As another preferred embodiment of the present application, a preparation method of a modified biomass demulsifier is disclosed, which specifically comprises the following steps: adding cotton into phosphoric acid, dissolving sufficiently, then heating to 50℃ and stirring for 2h, then adding ethanol to regenerate the dissolved cellulose and obtain cellulose oligomers, adding the cellulose oligomers into an aqueous amino compound solution, stirring uniformly, then transferring into a polytetrafluoroethylene reaction kettle, and then hydrothermally obtaining an aminated demulsifier. The cotton is natural cotton. The mass ratio of cotton to phosphoric acid is 3:100; and the mass ratio of cellulose oligomers to the aqueous amino compound solution is 2:45. The amino compound is at least one of ammonia, urea, ammonium bicarbonate and ethylenediamine.

[0034] Example 3

[0035] The aminated demulsifier prepared in Example 1 or 2 is applied to an oil-containing wastewater emulsion, which comprises the following steps: dispersing the aminated demulsifier in water to obtain a suspension, then mixing the suspension with the oil-containing wastewater emulsion at room temperature and standing for 10-30min.

[0036] After the demulsification is completed, most of the aminated demulsifier adsorbs oil and then floats on water together with the separated oil phase, and a small part of the aminated demulsifier is settled in water, which can be separated by long-time sedimentation or centrifugal separation, and the separation is relatively simple. Further, the addition amount of the aminated demulsifier in the oil-containing wastewater is 75mg / L.

[0037] Example 4

[0038] The present embodiment provides a preparation method of a modified biomass demulsifier, which is obtained by the following steps:

[0039] 2g of cotton is added into 100ml of phosphoric acid, dissolved sufficiently, then heated to 50℃ and stirred for 2h, then 50ml of ethanol is added and stirred for 20min to regenerate the cellulose oligomers, then the product is washed to neutral by centrifugation, and then freeze-dried.

[0040] 2g of cellulose oligomers is added into 50ml of an aqueous amino compound solution, stirred uniformly, then transferred into a polytetrafluoroethylene reaction kettle, then hydrothermally reacted at 220℃ for 24h to obtain an aminated demulsifier.

[0041] Example 5

[0042] The present embodiment provides a preparation method of a modified biomass demulsifier, which is obtained by the following steps:

[0043] 2g of cotton is added into 100ml of phosphoric acid, dissolved sufficiently, then heated to 50℃ and stirred for 2h, then 50ml of ethanol is added and stirred for 20min to regenerate the cellulose oligomers, then the product is washed to neutral by centrifugation, and then freeze-dried.

[0044] 2g of the cellulose oligomer was added into 50ml of the aqueous solution of the amino compound, stirred uniformly, and then transferred into a polytetrafluoroethylene reaction kettle, and then hydrothermal reaction was carried out at 200 DEG C for 24h to obtain the amino demulsifier.

[0045] Example 6

[0046] The amino demulsifier prepared in Example 4 was formulated into suspensions with different concentrations, and the demulsification performance of the amino demulsifier with different concentrations in the oil-containing wastewater emulsion was characterized.

[0047] 5 parts by weight of crude oil was added into 495 parts by weight of deionized water, stirred and mixed, heated to 60 DEG C, and then stirred at a speed of 11000r / min for 20min to obtain a stable oil-containing wastewater emulsion (oil-in-water emulsion).

[0048] Different parts by weight of the amino demulsifier prepared in Example 4 were added into water to formulate amino demulsifier suspensions with mass fractions of 0.3%, 0.25%, 0.2%, 0.15%, 0.1% and 0.05% respectively, and the obtained samples were recorded as experimental groups 1-6 respectively; the blank group was water, and the sample was recorded as experimental group 7.

[0049] 1 part by volume of the above experimental groups 1-6 was added into 20 parts by volume of the oil-containing wastewater emulsion, and then fully oscillated and mixed uniformly, and then placed at normal temperature for 30min, and the light transmittance and oil removal rate were measured, and the results are shown in Table 1.

[0050] Table 1 demulsification results of experimental groups 1-7

[0051] Group Demulsifier (mg / L) Transmittance (%) Oil removal rate (%) Experiment group 1 150 70.1 98.75 Experiment group 2 125 74.4 98.82 Experiment group 3 100 86.3 99.20 Experiment group 4 75 86.6 99.20 Experiment group 5 50 69.3 98.8 Experiment group 6 25 36.1 97.5 Experiment group 7 0 0 0

[0052] Note: In the table, "amino demulsifier (mg / L)" refers to the concentration of the amino demulsifier in the oil-containing wastewater emulsion.

[0053] As shown in Table 1, the amino demulsifier provided by the application has good demulsification performance, and after 30min of settling at normal temperature, the light transmittance of the oil-containing wastewater emulsion can reach 86.6%, and the oil removal rate can reach 99.20% at a concentration of 75mg / L

[0054] Example 7

[0055] Based on the amino demulsifier prepared in Example 4, experimental groups 8-12 were established in turn to characterize the demulsification performance of the amino demulsifier at different pH values.

[0056] 5 parts by weight of crude oil was added into 495 parts by weight of deionized water, stirred and mixed, the pH value was adjusted by adding hydrochloric acid or sodium hydroxide, heated to 60 DEG C, and then stirred at a speed of 11000r / min for 20min to obtain a stable oil-containing wastewater emulsion (oil-in-water emulsion).

[0057] The amino demulsifier prepared in Example 4 was added to water to prepare amino demulsifier suspensions with mass fractions of 0.05%, 0.1% and 0.15% respectively, and the samples were recorded as experimental groups 8-12 respectively;

[0058] 1 part by volume of the amino demulsifier suspension was added to 20 parts by volume of oil-containing wastewater emulsion with different pH values, and then mixed uniformly by oscillation, and then placed at room temperature for 30 min, and the light transmittance and oil removal rate were measured, and the results are shown in Table 2.

[0059] Table 2 Demulsification results of experimental groups 8-12

[0060] Group pH Transmittance % Oil removal rate % Experiment group 8 4 0.9 91.68 Experiment group 9 6 66.1 99.18 Experiment group 10 7 86.6 99.16 Experiment group 11 8 71.4 98.47 Experiment group 12 10 3.4 93.8

[0061] As can be seen from Table 2, the amino demulsifier provided by the application can achieve a higher demulsification efficiency near neutral.

[0062] The demulsifier provided by the application is suitable for demulsification of oil-containing wastewater emulsion, and has the characteristics of simple preparation method, wide source of raw materials, no pollution, easy degradation, excellent demulsification performance and the like.

[0063] The specific embodiments of the application described above do not constitute a limitation on the scope of protection of the application. Any various other corresponding changes and modifications made according to the technical concept of the application shall be included in the scope of protection of the claims of the application.

Claims

1. A method for preparing a modified biomass demulsifier, characterized by: The cotton is hydrolyzed by phosphoric acid to obtain cellulose oligomers, and then the cellulose oligomers are directly hydrothermally prepared with an amino compound to obtain an aminated demulsifier; The preparation method specifically comprises the following steps: adding cotton into phosphoric acid, dissolving sufficiently, heating to 40-70 DEG C, stirring for 1-3 h, then adding ethanol to regenerate the dissolved cellulose and obtain cellulose oligomers, adding the cellulose oligomers into an amino compound aqueous solution, stirring uniformly, transferring into a polytetrafluoroethylene reaction kettle, and then hydrothermally obtaining an aminated demulsifier.

2. The method for preparing a modified biomass demulsifier according to claim 1, characterized in that: The cotton is natural cotton.

3. The method for preparing a modified biomass demulsifier according to claim 1, characterized in that: The cotton is a product taking cotton as a raw material.

4. The method for preparing a modified biomass demulsifier according to claim 1, characterized in that: The mass ratio of the cotton to phosphoric acid is 1-5:

100.

5. The method for preparing a modified biomass demulsifier according to claim 1, characterized in that: The mass ratio of the cellulose oligomers to the amino compound aqueous solution is 2:40-50.

6. The method for preparing a modified biomass demulsifier according to claim 1, characterized in that: The amino compound is at least one of ammonia, urea, ammonium bicarbonate and ethylenediamine.

7. An aminated demulsifier prepared by the modified biomass demulsifier preparation method in claim 1.

8. Application of the aminated demulsifier prepared by the modified biomass demulsifier preparation method in claim 1 in oil-containing wastewater emulsion.

9. Use of the amino-functional demulsifier according to claim 8 in emulsions of oil-containing wastewater, characterized in that The method comprises the following steps: dispersing the aminated demulsifier in water to obtain a suspension, and then mixing the suspension with the oil-containing wastewater emulsion at room temperature and standing for 10-30 min.

10. Use of the amino-functional demulsifier according to claim 9 in emulsions of oily waste water, characterized in that: The addition amount of the aminated demulsifier in the oil-containing wastewater is 25-150 mg / L.

11. Use of the amino-functional demulsifier according to claim 10 in an emulsion of oil-containing wastewater, characterized in that: The addition amount of the aminated demulsifier in the oil-containing wastewater is 75-100 mg / L.

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