RU2125081C1 - Method of dehydrating crude oil - Google Patents

Abstract

FIELD: oil and gas production. SUBSTANCE: in order to improve quality of dehydrated petroleum, when treating any-type crude oils with different contents of salts, as demulsifier, substance is used selected from the group of beta- hydroxyethylenediamine, in particular: 1-polyethoxy-2-hexadecenyl(or heptadecenyl, or octadecenyl)imidazoline or 1,1-bis(polyethoxy)-2- hexadecenyl(or heptadecenyl, or octadecenyl)-2-imidazolinium acetate. EFFECT: enhanced dehydration efficiency. 2 tbl

Description

 The invention relates to the field of oil preparation, in particular, to methods for oil dehydration, and is intended for use both in oilfield processing plants and in refineries in the processes of deep oil dehydration.

 A known method of dehydration of oil by introducing into the water-oil emulsion of the de-emulsifier Diproxamine 157-65M, which is a block copolymer of ethylene and propylene oxides based on ethylene diamine (see, for example, A.C. USSR, N 447427, class C 10 G 33/04, 1972).

 The disadvantage of this known method is the lack of effectiveness in the dehydration of various types of oils.

Указанный способ предназначен для обезвоживания легких типов нефтей.Closest to the proposed method is methods of dehydration of oil, including the introduction of a water-in-oil emulsion of a demulsifier based on a nitrogen-containing compound, a product of incomplete hydrolysis of polyacrylonitrile with sodium hydroxide, of the following formula

The specified method is intended for dehydration of light types of oils.

 However, this known method does not provide high-quality dehydrated oil during demulsification of all types of oils (especially medium, heavy) with a high content of salts in them (residual salt content after processing is 33-34% of the original). In addition, the known method requires elevated temperatures of the process.

 Along with this, when implementing the known method, high-quality anti-corrosion protection of oilfield equipment is not provided.

 The aim of the present invention is to improve the quality of dehydrated oil in the processing of any type of oil while reducing the degree of corrosion and the consumption of demulsifier.

 An additional goal is to expand the range of demulsifiers suitable for various types of oils.

где
m = 15 - 70;
R - алкил C₁₆ - C₁₈,
или 1,1 - бис (полиэтокси)-2-гексадеценил (или гептадеценил) (или октадеценил)-2- имидозолиния ацетат (именуемый в дальнейшем "Оксимид") следующей формулы:

где
n + m = 34 - 70;
R - алкил C₁₆ - C₁₈.This goal is achieved by the fact that in the known method of dehydration and desalting of oil by introducing a demulsifier based on a nitrogen-containing compound into a water-oil emulsion, a substance selected from the group of β hydroxyethylethylenediamine derivatives is used as said demulsifier:
1-polyethoxy-2-hexadecenyl (or heptadecenyl) (or octadecenyl) imidazoline (hereinafter referred to as "Imidazoline") of the following formula:

Where
m = 15 - 70;
R is alkyl C ₁₆ - C ₁₈ ,
or 1,1 - bis (polyethoxy) -2-hexadecenyl (or heptadecenyl) (or octadecenyl) -2-imidosolinium acetate (hereinafter referred to as "Oximide") of the following formula:

Where
n + m = 34 - 70;
R is alkyl C ₁₆ - C ₁₈ .

 As it turned out unexpectedly, the use of demulsifiers of the specified composition in the claimed method ensured effective dehydration of light, medium and heavy oils while reducing the degree of corrosion. Apparently, this is a consequence of the physicochemical interaction and the influence of the structural elements of these demulsifiers on the natural stabilizers contained in the oil-water emulsion.

 The demulsifier "Imidazoline" is obtained by sequential alkylation of β-hydroxyethylethylenediamine with the formation of 2-hexa (hepta) (octa) decenyl imidazoline, and then the resulting product is hydroxyethylated.

"Imidazoline" is a liquid soluble in water, alcohols, chloroform, aromatic solvents and is characterized by the following indicators:
Density ρ $\genfrac{}{}{0ex}{}{\text{20}}{\text{4}}$ 976.4-1060 kg / m ³ ;
Viscosity V ₂₀ ^o C - 969 - 1500 cps;
Like m. - 1000 - 4500.

The demulsifier "Oksimid" is obtained by quaternization in solution at 55-75 ^o C of salts of 2-alkyl-substituted imidazolines with ethylene oxide (see AS USSR N 1703644, class C 07 D 233/22, from 1989).

"Oksimid" is a liquid soluble in water, alcohols, chloroform, aromatic solvents and is characterized by the following indicators:
Density ρ $\genfrac{}{}{0ex}{}{\text{20}}{\text{4}}$ 1018 - 1100 kg / m ³ ;
Viscosity V ₂₀ ^o C 1200 - 1800 Spa;
Like m. 1800 - 5000.

To implement the proposed method in the field, carry out the following operations in the following sequence:
- the above substance selected from the group of derivatives of β-hydroxyethylethylenediamine is introduced into the water-oil emulsion and mixed;
- heat it to a temperature of 30-80 ^o C;
- submit it to the settling apparatus;
- they suck 2-4 hours;
-separated water is discharged into the wastewater treatment system.

The proposed method in the laboratory was carried out as follows:
Example. They took 100 ml of the test oil, placed it in a graduated bottle, then the calculated amount of demulsifier was added to the bottle, the bottle was closed and mixed with not sharp, uniform shaking of only 50 shakes.

The test oil was heated in a water bath to +40 ^o C and in each bottle, the amount of water released for 2 hours was determined by graduation.

 For further tests (determination of the residual water content in oil), the corresponding samples immediately after the test were carefully removed from the bottle using a syringe and examined by known methods.

 The determination of the residual water content in oil was carried out in accordance with the American ASTM standard, which is based on the centrifugation method.

 Data on the quality of oil generated during the implementation of the proposed method are shown in table 1.

Assessment of the anticorrosive properties of demulsifiers used in the implementation of the proposed method was determined by the gravimetric method using a standard 3% sodium chloride solution with an H ₂ S content of 20 to 150 mg / L.

 The tests were carried out for 6 hours in a laboratory setup of the Wheel type in a closed system with a test medium moving speed of 0.4 m / s, as well as in hermetically closed circulation cells according to OST 39-099-79.

 Data on the corrosion activity of "Imidazoline" and "Oxymide" are shown in table 2.

 The data presented in table 1 show that when implementing the proposed method provides high efficiency demulsification of any type of oil, namely: light, medium and heavy. Moreover, a high degree of dehydration is achieved with a lower consumption of demulsifier.

 The data shown in table 2 show that when implementing the proposed method, the oilfield equipment will practically not corrode, since the demulsifiers used in the proposed method are characterized by high anticorrosion properties.

 Using the proposed method in oil treatment plants will ensure the achievement of high quality of the latter.

Claims (1)

A method for dehydrating oil by introducing a nitrogen-containing compound demulsifier into the water-oil emulsion, characterized in that a substance selected from the group of β-hydroxyethylethylenediamine derivatives: 1-polyethoxy-2-hexadecenyl (or heptadecenyl) or ) imidazoline of the general formula

where m = 17 - 70;
R is alkyl C ₁₆ - C ₁₈ ,
or 1,1-bis (polyethoxy) -2-hexadecenyl (or heptadecenyl) (or octadecenyl) -2-imidazolinyl acetate of the general formula

where n + m = 34 - 70;
R is alkyl C ₁₆ - C ₁₈ .

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