RU2712589C1 - Method for destruction of highly stable water-oil emulsions - Google Patents

Abstract

FIELD: oil and gas industry; technological processes.

SUBSTANCE: invention relates to destruction of high-stability water-oil emulsions and can be used in oil-producing and oil-refining industry, for example for destruction of high-stability water-oil emulsions (intermediate emulsion layers), stabilized with gel-like associates. Method involves adding a suspension of nanopowder of aluminum nitride in acetone to a water-oil emulsion and subsequent treatment of the mixture with ultrasound at frequency of 24.5 kHz and power of 1 kW in flow mode. Separation of treated emulsion into separate fractions (oil and water) is carried out either by settling or by centrifugation. In case of presence of solid mineral particles in emulsion after its destruction, they are deposited in the form of separate fraction.

EFFECT: method provides effective destruction of high-stability water-oil emulsions characterized by different content of "gel" with residual water content in oil phase of less than 1 wt%, wherein is characterized by continuity of processing and efficiency by using a suspension of aluminum nitride nanopowder in acetone, which is cheap and readily available reagent.

4 cl, 1 tbl, 3 ex

Description

The invention relates to methods for the destruction of oil-water emulsions (intermediate emulsion layers), mainly stabilized by gel-like associations, and can be used in the oil and oil refining industries.

Various methods are used to increase oil recovery and intensify the production of heavy highly viscous oils (microbiological effects, salt, thermal and clay acid treatments, as well as treatment of bottom-hole formation zones with aqueous solutions of surface-active substances and their compositions, solutions of polymers, alkalis, acids and other chemical reagents), often leading to the formation of persistent oil-water emulsions. For their destruction at the stage of oil preparation, various demulsifiers are used, leading to the formation of intermediate emulsion layers at the interface between the aqueous and oil phases. Such intermediate emulsion layers are highly stable oil-water emulsions in which the armor shells of water globules can be stabilized in addition to tar-asphaltene substances contained in large quantities in heavy, highly viscous oil, various mechanical impurities, iron sulfide and gel-like associations. The reason for the formation of gel-like associates in such emulsions is considered to be the use of a large number of demulsifying agents containing hydrophobic high molecular weight nonionic surfactants (block copolymers of ethylene and propylene oxides). Currently, highly stable oil-water emulsions stabilized by gel-like associates, it is almost impossible to destroy by known methods. Therefore, the cost of their disposal is required, which is economically disadvantageous.

In addition to the traditional methods for the destruction of stable water-oil emulsions (sedimentation, centrifugation, heating, the use of demulsifying reagents, etc.), methods using wave effects are actively developing.

A known method of dewatering a water-oil emulsion (RF Patent 2152817, 07/20/2000), which consists in the fact that the emulsion is mixed with an aqueous solution of a demulsifier, pre-treated in a constant magnetic field, and its sedimentation. The disadvantages of this method are the influence of temperature (for each type of water-oil emulsion, a temperature for separation and sludge is selected) and applicability to emulsions with a low water content, the higher the water content, the lower the degree of dehydration of the emulsion.

A known method of oil dehydration (Patent RF 2449004, 04/27/2012), which consists in mixing oil with magnetic fluid, separation of oil into dehydrated oil and the aqueous phase in a gradient magnetic field. The disadvantage of this method is the low separation efficiency of the water and oil phases (the residual water content in the emulsion is more than 10% vol).

A known method of destroying a water-oil emulsion in a container (RF Patent 2415902, 04/10/2011), including a set of rod electrodes, a disk electrode and a water-oil emulsion, by reorienting dipole water molecules on magnetic induction lines. The disadvantages of this method are the complexity of execution and high energy consumption.

A known method of destroying a water-oil trap emulsion (Patent RF 2183132, 06/10/2002), which consists in mixing the emulsion with the composition by separately and sequentially supplying the composition components to the emulsion one after another, followed by the action of the wave field on the aqueous phase in the electropulse mode during frequency spectrum generation from 200 kHz to the frequencies of infrared radiation by circulating through an electric pulse emitter back to the zone of the aqueous phase. The composition used is a composition containing an alkyl sulfonate reagent, a demulsifier based on a mixture of anionic and nonionic surfactants containing sodium alkylbenzenesulfonate sulfonol, and a nitrilotrimethylphosphonic acid reagent. The disadvantages of this method are the rather complex composition with a large number of different reagents, the need for long-term sedimentation and high energy consumption.

A known method of dehydration of an oil-water emulsion (RF Patent 2536583, 12/27/2014), which consists in the combined use of microwave and ultrasonic energy with experimentally selected parameters in frequency and intensity. The disadvantages of this method are the high level of complexity of the equipment used and the high energy consumption.

Known demulsifier for the destruction of oil-water emulsions (RF Patent 2491323, 08/27/2013), which is a nanosized powder of aluminum nitride (AlN). However, the well-known demulsifier is ineffective in the case of the destruction of highly stable oil-water emulsions stabilized by gel-like associates and has been tested only on model mixtures.

A known method of destroying a water-oil emulsion using ultrasonic treatment (RF Patent 2535793, 12/20/2014), including the process of processing the emulsion with a demulsifier, ultrasound and sedimentation process, the optimal level of specific acoustic power of ultrasound is previously determined. The known method has inherent disadvantages in that, for each water-oil emulsion and a fixed ultrasound frequency, empirically select their own values of the optimal level of specific acoustic power of ultrasound for the destruction of the emulsion, and also the lower the frequency of the ultrasound, the lower the degree of dehydration and the longer the processing time.

Closest to the claimed is a method of sample preparation of field resistant gel-containing water-in-oil emulsions (Romanova Yu.N., Musina N.S., Maryutina T.A. Influence of different types of wave action on the destruction of resistant gel-containing water-oil emulsions // Factory Laboratory. Diagnostics of materials. - 2018. - Volume 84. - No. 7. - P. 7-15), consisting in the use of ultrasonic treatment together with the addition of a suspension of aluminum oxide nanopowder in acetonitrile, in which the gel is destroyed and the aqueous and ftyanoy phases. The disadvantages of this method include the use of a larger amount of suspension, the frequency of the processing process, as well as the need to use acetonitrile, characterized by high cost and inaccessibility.

An object of the invention is to develop a method for the effective destruction of highly stable oil-water emulsions containing various amounts of “gel”, with a residual water content of less than 1% by weight in the oil phase, which is characterized by the continuity of the processing process and economy due to the use of a suspension of aluminum nitride nanopowder in acetone , which is a cheaper and more affordable reagent.

The problem is solved in that in the claimed method, the destruction is achieved by adding to the emulsion a suspension of aluminum nitride nanopowder in acetone, subsequent processing of the mixture with ultrasound at a frequency of 24.5 kHz and a power of 1 kW in flow mode and dividing the treated mixture into phases. The amount of suspension added to the emulsion is not more than 8% vol. In this case, to separate the treated mixture into phases, either centrifugation for 10 minutes or sedimentation during the day are used.

The technical result is achieved through the use of ultrasonic processing in flow mode with a frequency of 24.5 kHz and a power of 1 kW, together with the addition of a suspension of nanopowder of aluminum nitride in acetone (not more than 8% vol). This achieves the destruction of the "gel" contained in the emulsion, and the separation of the water and oil phases, as well as in the case of the presence of solid mineral particles in the emulsion, they precipitate.

The ultrasonic action with the addition of a suspension has a complex effect on the armor shells and the “gel” contained in the emulsions. Acetone promotes the breakdown of high molecular weight compounds, which leads to the destruction of the gel phase (the emulsion becomes less viscous, more fluid). Due to its diphilicity (the presence of hydrophilic (polar) and hydrophobic (nonpolar) parts), aluminum nitride nanopowder is redistributed at interphase boundaries, displacing the molecules of natural stabilizers from the surface of water globules due to higher surface activity. Its simultaneous interaction with both the aqueous and oil phases occurs, which, in turn, together with ultrasonic action leads to the destruction of the structural-mechanical barrier. Thus, there is a separation of water from oil.

As samples for destruction, commercial highly stable oil-water emulsions with the characteristics presented in Table 1 were used.

To implement the method, an ultrasonic apparatus is used, consisting of pumps supplying an emulsion and suspension, an ultrasonic generator and a flow reactor. For phase separation of emulsion samples that have been processed in an ultrasonic reactor, sedimentation is used during the day, or a centrifuge of the SM-6MT model is used to accelerate the process.

The method is carried out as follows: using pumps through a flow reactor of an ultrasonic unit, a highly stable oil-water emulsion and a suspension of aluminum nitride nanopowder in acetone are simultaneously fed under ultrasonic treatment. Moreover, the feed rate of the suspension is selected so that the volume is not more than 8% of the volume of the incoming emulsion. In addition, the speed of pumping the emulsion depends on the content of the "gel" - the lower the content of the "gel", the higher the speed. The resulting processed mixture is further sedimented or centrifuged.

Example 1. A sample of emulsion No. 1 with a gel content of 25.0% by mass and water 53.0% by mass of 200 ml and a suspension of aluminum nitride nanopowder in acetone with a volume of 16 ml (nanopowder weighing 32 mg) were pumped through the flow reactor of an ultrasonic unit . The speed of pumping the emulsion was 35 ml / min, suspension - 2.8 ml / min. The emulsion and suspension entering the stream were mixed and subjected to ultrasonic treatment with a frequency of 24.5 kHz and a power of 1 kW. The treated mixture was then centrifuged for 10 minutes at a speed of 1000 rpm. Without centrifugation, the treated mixture in the process of sedimentation was divided into phases during the day. The residual water content in the separated oil phase was less than 1% of the mass.

Example 2. Sample of emulsion No. 2 with a gel content of 8.0% by weight and water 62.0% by weight of 200 ml and a suspension of aluminum nitride nanopowder in acetone with a volume of 12 ml (nanopowder weight 24 mg) was pumped through a flow reactor of an ultrasonic unit . The emulsion pumping rate was 70 ml / min, and the suspension was 4.2 ml / min. The emulsion and suspension entering the stream were mixed and subjected to ultrasonic treatment with a frequency of 24.5 kHz and a power of 1 kW. The treated mixture was then centrifuged for 10 minutes at a speed of 1000 rpm. Without centrifugation, the treated mixture in the process of sedimentation was divided into phases during the day. The residual water content in the separated oil phase was less than 1% of the mass.

Example 3. A sample of emulsion No. 3 with a “gel” content of 16.0% by weight and water 58.0% by weight of 200 ml and a suspension of aluminum nitride nanopowder in acetone with a volume of 14 ml (nanopowder weighing 28 mg) were pumped through a flow reactor of an ultrasonic unit . The emulsion pumping rate was 50 ml / min, and the suspension was 3.5 ml / min. The emulsion and suspension entering the stream were mixed and subjected to ultrasonic treatment with a frequency of 24.5 kHz and a power of 1 kW. The treated mixture was then centrifuged for 10 minutes at a speed of 1000 rpm. Without centrifugation, the treated mixture in the process of sedimentation was divided into phases during the day. The residual water content in the separated oil phase was less than 1% of the mass.

Claims (4)

1. The method of destruction of highly stable water-oil emulsions, which consists in adding to the emulsion a suspension of aluminum nitride nanopowder in acetone, subsequent processing of the mixture with ultrasound at a frequency of 24.5 kHz and a power of 1 kW in flow mode and dividing the treated mixture into phases. 2. The method according to p. 1, which consists in the fact that the amount of suspension added to the emulsion is not more than 8% vol. 3. The method according to p. 1, which consists in the fact that for the separation of the treated mixture into phases using centrifugation for 10 minutes. 4. The method according to p. 1, which consists in the fact that for the separation of the treated mixture into phases using sedimentation during the day.