RU2244733C1 - Crude oil dehydration and desalting method - Google Patents

Abstract

FIELD: crude oil treatment.

SUBSTANCE: to oil emulsion is added surface-active demulsifying additive containing (i) aqueous solution of surfactant based on sodium salt of oxyethylated isononylphenol carboxymethylate expressed by general formula C₉H₁₉-C₆H₄-O-(-CH₂-CH₂O)_nCOONa, where n=10-12, (ii) self-emulsifying organosilicon compound, and (iii) sodium or calcium chloride salt.

EFFECT: increased demulsifying power.

1 tbl, 13 ex

Description

The invention relates to the field of application of anionic surfactants (ANPA) as a demulsifier for oil emulsions in the preparation of oil and gas condensates in oil fields and refineries.

Known methods of desalting and dehydration of oil using nonionic surfactants, which use polypropylene glycol ethers of polyethylene glycol or its derivatives with a molecular weight of 2500-10000 (A. with. The USSR N171065, BI N 10, 1965); polypropylene glycol derivatives of ethylene diamine or polypropylene glycol derivatives of ethylene glycol are proposed (A.S. USSR 168395, BI N 4, 1965); the use of a mixture of C10-C25 hydroxyethylated synthetic fatty acids (a.s. USSR No. 169166, BI N6, 1965); the use of hydroxyethylated fatty acids with a number of carbon atoms greater than 20 (a. from. USSR N 137213, BI N 7, 1961).

Of the modern domestic demulsifiers, Larsol-2 is known, it is produced according to TU 0258-001-470723231-98, Devon-1 according to TU 0258-002-12683932-98, which are various modifications of hydroxyethylated fatty acids (FFA) in hydrocarbon solvents.

The aim of the invention is the use of an effective water-soluble demulsifier based on ANPA in the conditions for the preparation of oil and gas condensates in oil fields and oil refineries, which will significantly reduce the consumption of demulsifier, improve the quality of the preparation of oil raw materials, while increasing the length of the overhaul run of oil refining plants, and improving the condition of the water basin due to the reduction of oil losses with wastewater and the use of ANPA with high biodegradability .

The goal is achieved through the use of a demulsifying additive, which is an aqueous solution of sodium salt of carboxymethylate of ethoxylated isononylphenol C ₉ H ₁₉ -O- (CH ₂ -CH ₂ O) _n COONa, where n = 10-12 moles of ethylene oxide (TU 2484-088- 05766565-2000) of sodium, calcium chloride salts (GOST 12257-93, GOST 450-77) and self-emulsifying organosilicon compounds (TU 6-02-1-529-86).

A demulsifying additive is prepared by sequentially introducing the indicated reagents into 100 g of water heated to a temperature of 50 ° C, g:

- sodium chloride, calcium 57

- sodium salt of carboxymethylate

ethoxylated isononylphenol 68

- self-emulsifying organosilicon

compound 1

with constant stirring, until they are completely dissolved. The resulting solution has the following characteristics:

- appearance The liquid is light yellow or light brown in color, the presence of fine suspension is allowed - density at 20 ° С, kg / m ³ , not less 1180 - mass fraction of ANPA,%, within 25-35 - crystallization temperature, ° C, not higher minus 25 - demulsification ability,% 100 - degree of desalination,%, not less 67

The effectiveness of the demulsifier was determined by the following method. A predetermined amount of crude oil (Vh) is poured into the separatory funnel, water (Vh ₂ about ref), alkali (v _NaOH ) and demulsifier (V _d ) are _added . The contents are emulsified on a mixing device for 2-3 minutes. After mixing, a separatory funnel with an oil emulsion is placed in a thermostatic chamber with a predetermined temperature for water sludge.

At certain intervals, measurements are made of the water that has settled out of the oil. The tests are carried out for three hours. In a water sample, pH indicators and the content of oil products are determined according to OST 38.01378-85, and in the settled oil, the chloride content according to GOST 21534-76.

The effectiveness of demulsifiers is evaluated by the demulsification ability (Xn ₂ about), the degree of desalination (Xc) of the same oil composition and the oil content in the drainage water (C _{n / a} ) under the following test conditions:

- the volume of crude oil, cm ³ 150

- volume of water (Vн ₂ on the outgoing.), cm ³ 15

- the volume of a 2% solution of NaOH (V _NaOH ), cm ³ 0.4

- consumption of 0.5% aqueous solution

demulsifier (V _d ), cm ³ 0,15-1,2

- temperature of thermal stabilization (t), ° C 80

The table “Comparative performance of demulsifiers” shows the effectiveness of the process of oil dehydration according to the proposed and known methods.

Demulsibility ability (Xn ₂ about) in percent calculated by the formula

where Vн ₂ about ref. - the volume of water (cm ³ ) taken to prepare the oil emulsion, in the examples taken exactly 15 cm ³ ;

Vn ₂ about the rest. - the amount of water released from the emulsion in 3 hours (cm ³ ).

The degree of desalination (Xc) in percent is calculated by the formula

where ss ref. - chloride content in the original oil, (mg / dm ³ );

SS Oct - chloride content in the settled oil, (mg / dm ³ ).

As can be seen from the data in the table, the effectiveness of the proposed composition of the demulsifier is higher than that of known industrial demulsifiers. The demulsification ability is 100%, and the degree of desalination is 67-71% at a demulsifier flow rate of 0.15 to 0.45 cm ³ , which corresponds to the industrial demulsifier consumption rate of 5-15 g / t of oil (examples 11, 12, 13).

For known demulsifiers, these indicators are as close as possible at the following optimal costs, g / t: for OZhK - 60 (example 3); Devon 10-15 (examples 5, 6); Larsol 10-15 (examples 9, 10). It should be noted that for Larsol the demulsification ability is lower by 3.4% compared to the proposed method, by 7% for Devon, and for OLC.

Losses of oil with drainage water have minimal values in examples 11, 12, 13 and are 120-180 mg / dm ³ , while for known demulsifiers they are 2-3 times higher (examples 3, 5), and for Larsol they are within 1160-1290 mg / dm ³ (examples 9, 10).

The method is illustrated by the following examples.

Examples 1-13. Carry out the method according to the methodology above, using desalted Arlan oil. The results of the method are shown in the table “Comparative performance of demulsifiers”, examples 11, 12, 13 in the stated conditions. Examples 1-10 are given for comparison.

As can be seen from the table, the application of the proposed method can significantly increase the efficiency of the process of preparing crude oil at a specific cost of demulsifier 5-15 g / t of oil.

Table
Comparative demulsifiers performance example demulsifier name the consumption of a 0.5% aqueous solution of a demulsifier, (Vd), cm ³ specific consumption of demulsifier, g / t of oil

см³ Volume of water discharged,

cm ³ Demulsification ability

% Chloride content in demineralized oil, (CC oc.), Mg / dm ³ The degree of desalination, (Xs),% Drainage characteristic hydrogen indicator (pH) the content of oil products (Sn / p), mg / DM ³ 1 0.15 fifteen 13.00 86.6 75.3 65.1 6.5 560 2 OZHK ^* 0.3 thirty 9.00 60.0 60,2 72,2 6.0 480 3 0.45 60 15.00 100 85.9 60,2 7.0 580 4 0.15 5 14.00 93.0 73,4 66.0 8.0 267 5 0.3 10 14.00 93.0 58.2 73.1 7.0 230 6 Devonian 0.45 fifteen 14.50 96.6 73.0 66,2 6.75 450 7 0.74 thirty 14.50 96.6 86.6 59.9 6.8 480 8 1,2 60 14.50 93.0 80.2 62.9 7.0 268 nine Larsol 0.3 10 14.50 96.6 95.2 43.5 7.0 1290 10 0.45 fifteen 14.50 96.6 88.0 48,2 7.0 1160 eleven 0.15 5 15.00 100 67.3 67.0 7.0 120 12 proposed 0.3 10 15.00 100 58.7 71.0 7.0 145 thirteen 0.45 fifteen 15.00 100 62,2 70.1 7.0 180 Note: OFA - ethoxylated fatty acids, demulsifier according to TU 38.101417-88

Claims (1)

The method of dehydration and desalting of oil by introducing a surfactant into the oil emulsion, characterized in that a demulsifying additive is used as a surfactant, including an aqueous solution of anionic surfactant (ANPA) based on sodium salts of carboxymethylate of ethoxylated C ₉ N ethoxylated isononyl phenols ₁₉ -C ₆ H ₄ -O - (- CH ₂ -CH ₂ O) _n COONa, and chloride salts of sodium, calcium and a self-emulsifying organic additive.