Aminated charcoal demulsifier as well as preparation method and application thereof

Abstract

The invention discloses an aminated biochar demulsifier which is prepared by the following steps: pretreating a biomass material by adopting maleic anhydride, and performing hydrothermal amination by utilizing an amination reagent. The method comprises the following steps: firstly, pretreating a biomass material; then, an amination reagent is introduced for hydrothermal amination, and carbonization and amination modification of the biomass material are achieved in one step; the obtained aminated biochar demulsifier has the characteristics of high efficiency, low dosage, short time and the like, the demulsification temperature can be reduced, and the applicability is wide; and the preparation method is simple, convenient and rapid, low in raw material and preparation cost, good in economic and environmental benefits and suitable for popularization and application.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemicals, and particularly relates to an aminated biochar demulsifier, a preparation method and an application thereof. Background Art

[0002] Crude oil emulsions are a common concern in the oilfield industry. Due to the lipophilic nature of natural surfactants in crude oil, oil favors the formation of emulsions upon contact with water. These natural surfactants include asphaltenes, resins, carboxylic acids, and solids such as clays and waxes. The adsorption of natural surfactants at the oil / water interface has a significant impact on delaying or inhibiting the formation of settling films. Naturally occurring surfactants adsorbed at the interface often inhibit or delay film formation, thereby protecting the oil emulsion from droplet coalescence and water separation. The stability of such emulsions can last from minutes to years, depending on the crude oil characteristics and the water content. Stable emulsions present numerous disadvantages in the oilfield, including pipeline corrosion, catalyst deactivation in downstream refinery operations, and increased transportation costs. Therefore, breaking the emulsion prior to transportation is crucial. Emulsion separation methods can be categorized into three categories: physical, biological, and chemical. Chemical demulsifiers are the most widely used in the oilfield.

[0003] Chemical demulsifiers are amphiphilic compounds with both hydrophilic and hydrophobic properties that adsorb at the oil-water interface. Demulsifiers generally exhibit similar behavior to emulsifiers, but may replace stabilizers in both the aqueous and oil phases, allowing the droplets to coalesce. In order to break the stable oil / water interface around the emulsified water droplets, chemical demulsifiers generally need to have stronger surface activity than natural emulsion stabilizers. It is worth noting that chemical demulsifiers are divided into polymer surfactants, nanoparticles and ionic liquids. For example, ethylene oxide-propylene oxide (EO-PO) block copolymers, silicone polyethers, dendrimers, biodegradable polymer surfactants, ionic liquids and nanoparticle-based demulsifiers have attracted increasing attention in the industrial field. However, the above-mentioned demulsifiers still have problems such as complex preparation process, high cost or high demulsification temperature and limited efficiency.

[0004] Therefore, seeking a new demulsifier that is widely available, non-toxic, environmentally friendly, low-cost and has excellent performance still faces great challenges. Summary of the Invention

[0005] The main purpose of the present invention is to address the problems and shortcomings of the existing technology and provide an aminated biochar demulsifier, which can demulsify stable oily wastewater, is green, environmentally friendly and easy to degrade, has the characteristics of high demulsification efficiency, low demulsifier dosage, short demulsification time, etc., and is suitable for promotion and application.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0007] An aminated biochar demulsifier is obtained by firstly pretreating a biomass material with maleic anhydride and then performing hydrothermal amination with an aminating reagent.

[0008] In the above scheme, the biomass material can be selected from agricultural by-products such as rice straw, rice husk, wheat stalk, corn stalk, corn cob, etc.

[0009] In the above solution, the particle size of the biomass material is 200-500 mesh.

[0010] In the above scheme, the pretreatment step includes: uniformly mixing the biomass material and maleic anhydride, heating the mixture for reaction, adding the mixture into water and treating the mixture with a high-speed homogenizer for a certain period of time to obtain pretreated biomass.

[0011] In the above scheme, the mass ratio of the biomass material to maleic anhydride is 1:(3-5).

[0012] In the above solution, the rotation speed of the high-speed homogenizer is 10000-23000 rpm, and the processing time is 20-60 min.

[0013] In the above scheme, the amination reagent can be selected from one or more of liquid ammonia, ammonia water, urea, ammonium chloride, ammonium nitrate, ethylenediamine, etc.

[0014] The preparation method of the above-mentioned aminated biochar demulsifier comprises the following steps:

[0015] 1) Biomass pretreatment;

[0016] The biomass material and maleic anhydride are mixed uniformly, heated to react, added to water and treated with a high-speed homogenizer for a certain period of time to obtain pretreated biomass;

[0017] 2) The pretreated biomass is uniformly dispersed in an amination reagent solution (aqueous solution), followed by a hydrothermal reaction, washing, and drying to obtain the aminated biochar demulsifier.

[0018] In the above scheme, the heating reaction temperature is 80-120° C. and the time is 2-10 h.

[0019] In the above scheme, the hydrothermal reaction temperature is 180-230° C. and the time is 12-24 hours.

[0020] In the above scheme, the concentration of the amination reagent solution is 10-30 wt%.

[0021] Application of the above-mentioned aminated biochar demulsifier in oily wastewater.

[0022] Furthermore, the oil content in the oily wastewater is 0.1-2 wt%.

[0023] In the above scheme, the concentration of the aminated biochar demulsifier in the oily wastewater is 10-100 mg / L.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The present invention first pre-treats the biomass material to change its size, morphology and structure, which is beneficial to ensuring and improving the subsequent amination improvement effect; then, an amination reagent is introduced to perform hydrothermal amination, thereby achieving carbonization and amination modification of the biomass material in one step to prepare an aminated biochar demulsifier; the obtained aminated biochar demulsifier can exhibit suitable wettability, and the biochar generated in the hydrothermal process has a large number of π conjugated systems, which can interact with natural emulsifiers in oily wastewater to promote demulsification; in addition, the simultaneous amination reaction causes a large number of amine groups to be grafted onto the surface of the obtained aminated biochar demulsifier, which presents a positive charge in the aqueous solution and can interact with negatively charged oil droplets, thereby reducing its stability and promoting the occurrence of the demulsification process; in addition, the biochar demulsifier in the present invention contains a certain amount of silicon dioxide, which can also improve the wettability and interfacial activity of the biochar and promote demulsification;

[0026] 2) The aminated biochar demulsifier obtained by the present invention has the characteristics of high efficiency, low dosage, short time, etc., and can reduce the demulsification temperature and has wide applicability;

[0027] 3) The raw materials used in the aminated biochar demulsifier of the present invention are mainly agricultural by-products, and the aminated biochar demulsifier is obtained after simple pretreatment and hydrothermal amination treatment; the chemical agents used in the preparation process can be recycled and reused to reduce production costs; it can effectively expand the scope of application of agricultural by-products and increase the utilization of agricultural by-product resources; and the preparation method involved is simple and fast, with low raw material and manufacturing costs, and has good economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the FTIR spectrum of the aminated biochar demulsifier obtained in Example 1. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] Example 1

[0031] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0032] 1) Washing, drying, and crushing rice straw, and then passing it through a 500-mesh sieve to obtain rice straw powder; mixing 2 g of rice straw powder and 8 g of maleic anhydride, reacting them at 100° C. for 8 h, washing away excess reactants with water, adding a certain amount of water to form a dispersion, and treating them with a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass;

[0033] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of 30% ammonia water, and then placed in a high-pressure reactor to react at 230° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0034] Depend on Figure 1 It can be seen that 3020cm -1 The peak at 1618cm is caused by the bending vibration of NH. -1 The peak at is caused by -NH2 stretching vibration. These results indicate that the target aminated biochar demulsifier was successfully synthesized.

[0035] Example 2

[0036] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0037] 1) Wash, dry, and grind rice husks, then pass through a 200-mesh sieve to obtain rice husk powder; mix 2 g of rice husk powder and 10 g of maleic anhydride, react at 110° C. for 8 h, wash away excess reactants with water, add a certain amount of water to form a dispersion, and treat with a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass;

[0038] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of 30 wt% urea solution, and then placed in a high-pressure reactor for reaction at 230° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0039] Example 3

[0040] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0041] 1) Wheat was washed, dried, and ground, and then passed through a 500-mesh sieve to obtain wheat flour; 2 g of wheat flour and 6 g of maleic anhydride were uniformly mixed, reacted at 80° C. for 8 h, excess reactants were washed with water, and a certain amount of water was added to form a dispersion, which was treated with a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass;

[0042] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of a 30 wt% aqueous solution of ethylenediamine, and then placed in a high-pressure reactor for reaction at 230° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0043] Example 4

[0044] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0045] 1) Wash, dry, and grind rice straw, then pass through a 500-mesh sieve to obtain rice straw powder. Mix 2 g of rice straw powder and 8 g of maleic anhydride, react at 100°C for 8 h, wash off excess reactants with water, add a certain amount of water to form a dispersion, and homogenize using a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass.

[0046] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of 10 wt% urea solution, and then placed in a high-pressure reactor for reaction at 230° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0047] Example 5

[0048] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0049] 1) Washing, drying, and crushing rice straw, and then passing it through a 500-mesh sieve to obtain rice straw powder; mixing 2 g of rice straw powder and 8 g of maleic anhydride, reacting them at 100° C. for 8 h, washing away excess reactants with water, adding a certain amount of water to form a dispersion, and treating them with a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass;

[0050] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of 30 wt% urea solution, and then placed in a high-pressure reactor for reaction at 200° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0051] Example 6

[0052] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0053] 1) Wash, dry, and grind rice straw, then pass through a 500-mesh sieve to obtain rice straw powder. Mix 2 g of rice straw powder and 8 g of maleic anhydride, react at 100°C for 8 h, wash off excess reactants with water, add a certain amount of water to form a dispersion, and homogenize using a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass.

[0054] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of 30 wt% urea solution, and then placed in a high-pressure reactor for reaction at 180° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0055] Comparative Example 1

[0056] A biomass demulsifier, the preparation method of which comprises the following steps:

[0057] 1) Wash, dry, and grind rice straw, then pass through a 500-mesh sieve to obtain rice straw powder. Mix 2 g of rice straw powder and 8 g of maleic anhydride, react at 100°C for 8 h, wash off excess reactants with water, add a certain amount of water to form a dispersion, and homogenize using a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass.

[0058] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of water, and then placed in a high-pressure reactor at 230° C. for 24 h, washed, and dried to obtain a biomass demulsifier.

[0059] Comparative Example 2

[0060] A biochar demulsifier, the preparation method of which comprises the following steps:

[0061] The rice straw was washed, dried, and crushed, and then passed through a 500-mesh sieve to obtain rice straw powder. 10 g of the rice straw powder was then directly carbonized at 400°C in an oxygen-free environment to obtain a biochar demulsifier.

[0062] Comparative Example 3

[0063] An aminated biochar demulsifier, the preparation method of which comprises the following steps:

[0064] 1) Washing, drying, and crushing rice straw, and then passing it through a 500-mesh sieve to obtain rice straw powder; mixing 2 g of rice straw powder and 8 g of acetic anhydride, reacting them at 100° C. for 8 h, washing away excess reactants with water, adding a certain amount of water to form a dispersion, and treating the mixture with a high-speed homogenizer at 23,000 rpm for 30 min to obtain pretreated biomass;

[0065] 2) 2 g of pretreated biomass was evenly dispersed in 20 g of 30% ammonia water, and then placed in a high-pressure reactor to react at 230° C. for 24 h, washed, and dried to obtain an aminated biochar demulsifier.

[0066] Application Examples

[0067] The demulsifiers obtained in Examples 1-6 and Comparative Examples 1-3 were respectively applied to demulsify oily wastewater, and the specific steps were as follows:

[0068] 1) 1 part by weight of crude oil was added to 99 parts by weight of water, stirred and mixed, heated to 45° C., and then stirred at 10,000 rpm for 30 minutes until a stable oil-in-water emulsion (oil content: 1 wt%) was formed;

[0069] 2) adding a certain amount of the demulsifiers obtained in Examples 1-5 and Comparative Examples 1-3 to 20 parts by weight of deionized water to prepare aqueous dispersions of the demulsifiers with a mass fraction of 0.2% respectively;

[0070] 3) 1 part by volume of the above demulsifier aqueous solution was added to 20 parts by volume of the above oil-in-water emulsion (the demulsifier concentration was 100 mg / L), shaken thoroughly to mix, and allowed to stand at room temperature for 30 minutes. The transmittance of the aqueous phase was then measured using an SP2100 spectrophotometer.

[0071] Table 1

[0072] serial number Transmittance% Example 1 92.1 Example 2 92.5 Example 3 91.8 Example 4 84.9 Example 5 86.4 Example 6 81.3 Comparative Example 1 40.3 Comparative Example 2 11.2 Comparative Example 3 63.7

[0073] As can be seen from Table 1, the aminated biochar demulsifier provided by the present invention can exhibit high demulsification efficiency under normal temperature and low concentration conditions, and the water phase is clear after demulsification.

[0074] In summary, the aminated biochar demulsifier provided by the present invention can be used for rapid and efficient demulsification of oilfield oily wastewater, has the characteristics of cheap and easy availability of raw materials, recycling of biomass waste, no pollution and easy degradation, and simple preparation method.

[0075] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. An aminated biochar demulsifier, characterized in that Firstly, maleic anhydride is used to pretreat the biomass material, and then an amination reagent is used to perform hydrothermal amination to obtain the obtained biomass material.

2. The aminated biochar demulsifier according to claim 1, characterized in that The amination reagent is one or more of liquid ammonia, ammonia water, urea, ammonium chloride, ammonium nitrate, and ethylenediamine.

3. The aminated biochar demulsifier according to claim 1, characterized in that The biomass material is one or more of rice straw, rice husk, wheat stalk, corn stalk and corn cob.

4. The aminated biochar demulsifier according to claim 1, characterized in that The pretreatment step comprises: uniformly mixing the biomass material and maleic anhydride, heating the mixture for reaction, adding the mixture into water and treating the mixture with a high-speed homogenizer to obtain pretreated biomass.

5. The aminated biochar demulsifier according to claim 4, characterized in that The mass ratio of the biomass material to maleic anhydride is 1:(3-5).

6. The aminated biochar demulsifier according to claim 4, characterized in that The rotation speed of the high-speed homogenizer is 10000-23000 rpm, and the processing time is 20-60 min.

7. The method for preparing the aminated biochar demulsifier according to any one of claims 1 to 6, characterized in that: The steps include: 1) Biomass pretreatment; The biomass material and maleic anhydride are mixed uniformly, heated to react, added to water and treated with a high-speed homogenizer for a certain period of time to obtain pretreated biomass; 2) The pretreated biomass is uniformly dispersed in an amination reagent solution, followed by a hydrothermal reaction, washing, and drying to obtain the aminated biochar demulsifier.

8. The preparation method according to claim 7, characterized in that The heating reaction temperature is 80-120° C. and the reaction time is 2-10 h.

9. The preparation method according to claim 7, characterized in that The hydrothermal reaction temperature is 180-230° C., and the reaction time is 12-24 hours.

10. Application of an aminated biochar demulsifier in oily wastewater.

Images