RU2244100C1 - Paraffin deposit-preventing hydrophilic property imparting composition - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention is intended to protect inner surface of transmission pipelines against asphalt-tar-paraffin deposits and provides appropriate composition containing 0.5-10% polyvinyl alcohol, 0.01-1% nonionic surfactant (FK 2000 PLUS), and water.

EFFECT: prolonged pipeline protection effect of composition and manifested demulsification activity.

1 dwg, 5 tbl, 5 ex

Description

The invention relates to the oil industry and can be used to protect the inner surface of transport pipelines from asphalt-resin-paraffin deposits. The mechanism of protective action is to create a hydrophilic protective film on the surface of the equipment, preventing the adhesion of paraffin crystals and the formation of a layer of deposits firmly bonded to the metal surface.

A known composition for hydrophilization of the inner surface of pipelines, including,% wt .:

carboxymethyl cellulose 32

hexametaphosphate 60

ethoxylated alcohol 8

used in a working concentration of 3.2 g / l of water. (V.E. Gubin, A.A. Emkov. Transfer of high-viscosity oils with a near-wall layer of a wetting composition. // Transport of oil and oil products. "1980 - No. 4. - S. 3-6).

The disadvantages of this composition are:

- protection of the pipeline from tar-paraffin deposits for a short time;

- a negative impact on the processes of primary preparation of irrigated oils. So, this composition helps to stabilize the water-oil emulsion, thereby complicating the process of demulsification.

Closest to the proposed invention is a composition for hydrophilization of the inner surface of pipelines, including,% wt .:

polyacrylamide 0.02-2

carboxymethyl cellulose 0.1-0.5

nonionic surfactant 0.001-0.01

water rest

(F.A. Kamenshchikov, Ya.L. Smirnov, V.E. Yupashevsky, P.N. Fomin. Composition for preventing paraffin deposition // USSR Author's Certificate No. 794193, Е 21 В 43/00, 01/07/1981, 3 from).

The disadvantages of the known composition are:

- ensuring the protection of pipelines from tar-paraffin deposits for a short time;

- a negative impact on the processes of primary preparation of irrigated oils. The specified composition helps to stabilize the oil-water emulsion, complicating the process of demulsification.

The objective of the present invention is to provide a hydrophilizing composition that protects pipelines from paraffin deposits for a longer time and at the same time exhibits the properties of a demulsifier.

The problem is solved due to the fact that in the hydrophilizing composition to prevent deposition of paraffin containing polymer, nonionic surfactant nonionic surfactants and water, it contains polyvinyl alcohol as a polymer, as an nonionic surfactant - an additive FC 2000 PLUS in the following ratio of components,% wt .:

polyvinyl alcohol 0.5-10

additive FC 2000 PLUS 0.01–1

water rest

Additive FC 2000 PLUS is a composition of triglycerides, natural surfactants, vegetable fatty acids and polyethylene glycol ethers saponified with potassium hydroxide.

Polyvinyl alcohol, the molecules of which form strong hydrogen bonds with water molecules, is used as the main component of the hydrophilizing composition. This explains the stronger retention of the aqueous film by a layer of a hydrophilizing composition based on polyvinyl alcohol, which increases the protective properties of the composition. An auxiliary component that improves the wettability of the metal surface and the washing properties of the composition is nonionic surfactant - an additive of FC 2000 PLUS, which does not cause the formation of precipitation in water of any mineralization. Moreover, the proposed ratio of the components is due to the following. At a concentration of the main component - polyvinyl alcohol - below 0.5% wt. the process of its adsorption on a metal surface becomes difficult and a strong polymer protective film does not form on the metal surface. The use of a solution of polyvinyl alcohol with a concentration above 10% wt. impractical for economic reasons. Solutions of nonionic surfactants - additives FC 2000 PLUS in concentrations below 0.01% wt. - do not have noticeable laundering properties; an increase in the concentration of nonionic surfactant above 1% wt. not economically feasible. In addition, concentrated solutions of the additive FC 2000 PLUS can help stabilize the oil-water emulsion, which will reduce the demulsifying properties of the composition.

Thus, the set of essential features set forth in the claims, allows to achieve the desired technical result. Namely, the claimed composition provides protection of pipelines from paraffin deposits for a longer time and at the same time exhibits the properties of a demulsifier.

Specific implementation examples

We conducted laboratory studies comparing the effectiveness of the developed composition and its prototype. Laboratory studies were carried out on the installation for the study of the waxing process based on the well-known method of “cold rod”.

A diagram of a laboratory setup for studying the process of paraffin deposition by the "cold rod" method is presented in the drawing: 1 - beaker; 2 - oven / magnetic stirrer; 3 - metal "cold rod"; 4 - firing pin.

300 ml of condensate were poured into a thermostatic cup 1. The temperature was raised to 70 ° C and stirring was switched on for 20 minutes with a magnetic stirrer 2. Then the temperature was reduced to 60 ° C and the steel cylinder 3, the surface of which was previously ground, degreased with hexane and alcohol, was dried and treated with the studied aqueous polymer solution in for 1 hour. Inside, the cylinder was cooled with ice. Thus, a temperature drop of 60 ° C was created on the cylinder wall. During the experiment, the condensate in the glass was stirred with a magnetic stirrer for 15 minutes, after which the cylinder was removed from the glass, ice was poured out and water was poured at a temperature of 25 ° C. The mass of deposits remaining on the cylinder was determined by the gravimetric method.

To evaluate the effectiveness of the hydrophilizing effect of aqueous polymer solutions, the following formula is used:

where m ₀ is the mass of deposits in the control experiment;

m ₁ is the mass of deposits on a hydrophilized surface.

For testing, we used a 20% water-oil emulsion artificially prepared from produced water and gas condensate from the Pribrezhnoye deposit in the Krasnodar Territory. The group composition of gas condensate and physicochemical parameters of produced water are given below.

Group hydrocarbon composition of gas condensate:

Name of fractions Content of fractions,% wt.

Petroleum fraction (NK-60 C) 2.0

Aromatic hydrocarbons 13.2

Paraffin hydrocarbons 58.0

Naphthenic hydrocarbons 26.1

Unsaturated hydrocarbons 0.7

Total 100.0

Paraffin content 4.3

Physical and chemical indicators of formation water:

Name of indicators Value of indicators

Density 1,1709 g / cm ³

PH value, pH 7.52

Hardness 1.4 mmol / dm ³

The efficacy of the following formulations was compared:

Example No. 1 (prototype) 1.5 g of polyacrylamide is dissolved with constant stirring in 200 g of water heated to 50 ° C. 0.9 g of carboxymethyl cellulose is dissolved with constant stirring in 97.6 g of water heated to 50 ° C. The resulting solutions are combined, add 0.015 g of OP-10, mix thoroughly until a homogeneous liquid.

Example No. 2 (proposed) 3 g of a dry polyvinyl alcohol powder is dissolved in 295.5 g of water heated to 50 ° C with constant stirring, 1.5 g of nonionic surfactant FC 2000 PLUS are added. The mixture is thoroughly mixed until a homogeneous liquid is obtained.

Physico-chemical characteristics of the reagents are shown in table 1.

Examples No. 3-5 perform analogously to example No. 2, changing the quantitative ratio of the components included in the proposed composition.

The specific compositions of the hydrophilizing composition and the test results are presented in table 2. The influence of the studied compositions on the process of separation of oil-water emulsions is presented in table 3.

As can be seen from the above test results of the claimed composition, the proposed composition more effectively protects the equipment from paraffin deposits. In addition, it has a positive effect on the process of separation of the extracted emulsion, that is, it exhibits the properties of a demulsifier. The advantage of the claimed structure is the use of components manufactured by domestic industry.

Table 1
Physico-chemical characteristics of the reagents. Polyvinyl alcohol (TU 2215-018-00203766-98) Name of indicator Indicator value Dynamic viscosity, Pa · s 10 ³ , no more thirty Mass fraction of volatiles,%, no more 6 Mass fraction of acetate groups,%, no more 1 Solubility in water,%, not less than 99.0 Mass fraction of sodium acetate,%, no more 12 Warranty period of storage 1 year. FC 2000 PLUS (TU 2458-001-49472578-98) Name of indicator Indicator value Appearance darkish viscous liquid Moisture content No more than 15% pH 8-9 Foaming activity no more than 60 cm ³ Reducing the surface tension of a 0.5% aqueous solution at the border with kerosene not less than 70%

table 2
The study of the effectiveness of hydrophilizing compounds Reagent The mass of deposits, g Efficiency% Non-hydrophilized 2,731 metal surface Example 1 (prototype) 0.52 81 Example 2 (proposed) 0.34 87.5 Example 3 (0.5% wt. PVA, 0.01% 0.49 82 wt. FC 2000 PLUS) Example 4 (10% wt. PVA, 1% wt. 0.30 89 FC 2000 PLUS) Example 5 (5.25% wt. PVA, 0.5% 0.38 86 wt. FC 2000 PLUS)

Table 3
The effect of polymer solutions on the separation of oil-water emulsions Polymer grade Time min 5 10 twenty 40 60 90 Emulsion without additives The emulsion is not divided Example 1 (prototype) 0 0 0 10 fifteen thirty Example 2 (proposed) fifty 88 100 100 100 100 Example 3 fifty 88 100 100 100 100 Example 4 75 90 100 100 100 100 Example 5 fifty 90 100 100 100 100 The table shows% vol. separated water.

Claims (1)

A hydrophilizing composition for preventing paraffin deposits in pipelines, containing a polymer, nonionic surfactant, nonionic surfactants and water, characterized in that it contains polyvinyl alcohol as a polymer, and an additive FK 2000 PLUS in the following ratio of components, wt. %: Polyvinyl alcohol 0.5 - 10 Additive FC 2000 PLUS 0.01 - 1 Water Else