RU2238282C1 - Method for preparing agent for reducing hydrodynamic resistance of hydrocarbon liquid - Google Patents

Abstract

FIELD: polymers, chemical technology.

SUBSTANCE: polymeric agents used for reducing resistance cause partial lamination of turbulent flow in boundary region that results to increase of total consumption of liquid. Invention relates to methods for preparing high-molecular polymers of α-olefins soluble in hydrocarbon liquids and can be used for elevating throughput capacity of oil pipelines and product pipelines. Method involves (co)polymerization of higher α-olefins on microspherical titanium trichloride treated preliminary with higher (C₆-C₁₆)-α-olefin taken in the amount 0.13-0.52 M of olefin per 1.0 M of TiCl₃ in the presence of organoaluminum compound as a co-catalyst. Preliminary polymerization causes grinding TiCl₃ particles to colloidal dispersity degree and some elevating medium viscosity value. Application of catalyst treated by this method eliminates the necessity for stirring reaction mass excepting for factor of mechanical destruction of polymer formed. The claimed method provides preparing superhigh-molecular (co)polymers eliciting extremely high effectiveness for reducing hydrodynamic resistance of hydrocarbon liquids.

EFFECT: improved preparing method, enhanced and valuable properties of agent.

2 cl, 5 ex

Description

The invention relates to methods for producing high molecular weight polymers of α-olefins soluble in hydrocarbon liquids, and can be used to increase the throughput of oil pipelines and product pipelines.

Polymeric drag reduction agents cause a partial laminarization of the turbulent flow in the near-wall region, which leads to an increase in the total fluid flow.

There are three necessary conditions for reducing resistance:

1. Good solubility of the polymer in a hydrocarbon liquid;

2. Ultra high molecular weight polymer;

3. Turbulent flow of fluid in the pipeline.

There are two types of anti-turbulent additives (PTP) based on polymers of higher α-olefins. The first type of additives is mortar type additives (Russian patent No. 2075485, BI No. 8, 1997), or, as they are also called, gel additives. Get them by polymerization of a higher α-olefin in a hydrocarbon solution. The product is a viscous solution having the consistency of honey.

Solution-type anti-TB drugs have some disadvantages. Firstly, the mechanism of polymerization of higher α-olefins in solution is such that an ultra-high molecular weight polymer is obtained only at the initial stage of polymerization, and it must be interrupted at 20% monomer conversion (US Pat. No. 4,433,123, MKI C 08 F 004/64; C 08 F 010/00, publ. 02.21.1984), since further polymerization leads to the formation of a ballast polymer that is not active in reducing resistance.

Secondly, the content of the nutrient in the mortar type additives cannot exceed 10 - 12%, otherwise the system will lose fluidity and there will be difficulties with pumping it into the pipeline, therefore transportation costs are the main obstacle to their use, especially at large distances from the production site.

Suspension additives are free of these disadvantages. Their preparation includes the polymerization of higher α-olefins in bulk, where the solvent content does not exceed several percent (US Pat. No. 6172151, MKI C 08 J 005/05, publ. January 9, 2001), then the resulting rubbery polymer is crushed at cryogenic temperatures and prepared a suspension of ground polymer in an aqueous or non-aqueous medium (US Pat. No. 4,837,249, MKI B 05 D 005/08, publ. 06/06/1989; US Pat. No. 4826728, MKI B 32 V 009/10; B 32 V 025/16; B 32 B 027/00, publ. 05/02/1989; US Pat. No. 4720397, MKI B 05 D 005/00, publ. 01/19/1988).

The polymer content in the additives of the suspension is from 20% or more, respectively, and transportation costs are reduced. In addition, the procedure for injecting suspension additives is somewhat simpler than mortar, due to the fact that the latter have a much higher viscosity.

An important fact is that during polymerization in the mass of monomer almost no ballast polymer with a low molecular weight is formed.

Closest to the proposed invention is a method for producing an agent for reducing the hydrodynamic resistance of hydrocarbon liquids (RF patent No. 2171817, MKI C 08 F 10/14, C 08 F 4/654, publ. 08/10/2001). In example No. 4 presents data on the polymerization of hexene in bulk (monomer content of 99%). The polymerization was initiated with a titanium-magnesium catalyst and triethylaluminum (cocatalyst) at 20 ° C. The polymerization process itself was carried out at 0 ° C with stirring for 5 hours. The resulting polymer had a 42.8% decrease in resistance in diesel fuel at a concentration of 10 ppm (0.001%).

The disadvantages of this method include the low efficiency of the polymer in reducing the hydrodynamic resistance, as well as the need for mixing the reaction mass during its synthesis.

The task of the invention is to increase the effectiveness of the polymer agent to reduce resistance and simplify the technology for its preparation.

The problem is achieved in that as the initiator of the polymerization of the higher α-olefin with the number of carbon atoms from 6 to 16, microspherical titanium trichloride in the presence of an organoaluminum compound is used as cocatalyst, pre-treated with a higher α-olefin in an amount of 0.13 - 0.52 mol olefin per 1 mol of TiCl ₃ .

The catalytic complex is a rapidly delaminating suspension of solid titanium trichloride in a solution of an organoaluminum compound in a hydrocarbon. When processing it with a small amount of a higher α-olefin with the number of carbon atoms from 6 to 16 in the indicated ratio, the following occurs:

A) TiCl ₃ particles are reduced in size, reaching a colloidal degree of dispersion;

B) the viscosity of the suspension increases.

The treated catalytic complex is a homogeneous, moderately viscous liquid that does not separate during storage and is convenient to dose.

Polymerization of the monomer in the presence of the treated catalyst complex leads to the formation of a polymer having extremely high efficiency in reducing hydrodynamic resistance.

In addition, the processed titanium trichloride during polymerization in the mass of monomer (monomers) due to the high degree of dispersion does not settle to the bottom even in the absence of mixing, therefore, the polymerization was carried out under static conditions. Perhaps this is one of the reasons for the high efficiency of the obtained polymer, since macromolecules of very long lengths are sensitive to mechanical degradation.

The use of titanium-magnesium catalyst in the prototype allows you to finish the polymerization in 5 hours. However, it is known that the lower the polymerization rate, the higher the molecular weight of the polymer. And the higher the molecular weight of the polymer, the higher its effectiveness in reducing hydrodynamic resistance. The use of titanium trichloride processed by the proposed method allows to increase the polymerization time to several days, which leads to the formation of a polymer of extremely high efficiency.

When comparing the essential features of the present invention revealed that the signs:

- the use of microspherical titanium trichloride in combination with trialkylaluminum (or dialkylaluminium chloride), pre-treated with a small amount of α-olefin, to obtain ultra-high molecular weight (co) polymers C ₆ -C ₁₆ soluble in hydrocarbon liquids;

- the absence of mechanical effects on the polymerization medium, which eliminates the mechanical destruction of the resulting polymer;

- increase the polymerization time to several days to increase the efficiency of (co) polymers;

are new and not described in the prototype.

The following examples reveal the essence of the invention.

Example 1

220 ml of octene were poured into a 500 ml vessel and purged with nitrogen at room temperature for 30 minutes. Then, 0.5 ml of the treated catalytic complex was added (see below), after which nitrogen sparging was stopped. The vessel was tightly closed and left alone at room temperature (17 ° C) for 24 hours. During this time, the reaction mixture gradually lost fluidity and solidified, turning into a rubbery material. The polymer yield was 95%. The consumption of the catalyst was 0.19 g. The decrease in the resistance of AI 80 gasoline with a Reynolds number of 4,500 was 60.7% at a polyo-octene concentration of 2.0 ppm (0,0002%).

The pretreatment of the catalytic complex was as follows: to a suspension of 147.5 g of microspherical TiCl ₃ in 300 ml of a solution of diethylaluminium chloride at a concentration of 200 g / l, 40 ml of 1-octene was added with stirring. As a result, the suspension became a viscous, homogeneous liquid, not delaminating during storage. Instead of octene, any higher α-olefin containing from 6 to 16 carbon atoms, as well as mixtures thereof, is suitable for pretreatment of the catalytic complex.

The magnitude of the decrease in hydrodynamic resistance (DR) was determined on a turbulent rheometer, which measured the time of expiration of a fixed volume of fluid through the pipe in a turbulent mode. DR was calculated by the formula

DR (%) = 100 $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ -t $\genfrac{}{}{0ex}{}{\text{2}}{\text{p}}$ ) / t $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ ,

where t ₀ is the expiration time of a fixed volume of solvent (AI-80 gasoline) at a given shear stress on the pipe wall;

t _p is the expiration time of the same volume of polymer solution at the same shear stress.

Example 2

The same as in example 1, only triethylaluminum (a compound of the type A1R ₃ ) was used as a cocatalyst. The polymerization was carried out for 2 days. The obtained polyoctene reduced the hydrodynamic resistance of AI - 80 gasoline by 58.6% at a concentration of 2.5 ppm.

Example 3

The same as in example 1, only instead of octene in the synthesis of the polymer used an equimolar mixture of octene and decene. The polymerization was carried out for 2 days. The resulting copolymer reduced the hydrodynamic resistance of AI - 80 gasoline by 61.6% at a concentration of 1.5 ppm.

Example 4

The same as in example 1, only instead of octene in the synthesis of the polymer used an equimolar mixture of hexene and hexadecene. The same mixture was used instead of octene for pretreatment of the catalytic complex. The polymerization was carried out for 24 hours. The resulting copolymer reduced the resistance of AI-80 gasoline by 62.3% at a concentration of 5.0 ppm.

Example 5

The same as in example 1, only the reaction mixture after 30 minutes after applying the pre-treated catalyst complex was placed in a cool room with a temperature of 4 ° C. The polymerization was carried out for 2 days. The resulting polymer reduced the resistance of AI-80 gasoline by 51.7% at a concentration of 1.0 ppm.

As can be seen from the examples, the inventive method allows to obtain highly efficient polymers capable of reducing the hydrodynamic resistance of hydrocarbon liquids by 50-60% at a concentration of 1-5 ppm.

Claims (2)

1. A method of obtaining an agent for reducing the hydrodynamic resistance of hydrocarbon liquids by (co) polymerizing higher α-olefins in the presence of a titanium-containing catalyst and an organoaluminum co-catalyst, characterized in that the catalyst is microspherical titanium trichloride pretreated with a higher α-olefin C ₆ -C ₁₆ in the amount of 0.13-0.52 M olefin per 1.0 M TiCl ₃ . 2. The method according to claim 1, characterized in that the polymerization is carried out in the absence of mixing.