RU2278146C1 - Method for dehydration and desalting of petroleum - Google Patents

Abstract

FIELD: petroleum chemistry, chemical technology.

SUBSTANCE: invention relates to using anionic surface-active substances as a petroleum-soluble demulsifying agent used in processes of deep dehydration and desalting of the oil raw in it preparing to the further processing. For realization of method demulsifying additive is added to the oil emulsion by dosing pump or into pipeline directly after a hole, or in the raw feeding line to a device for petroleum preparing. As a demulsifying additive method involves using solution of anionic surface-active substance based on carboxymethylates of oxyethylated isononylphenols of the formula: C₉H₁₉-C₆H₄-O-(CH₂-CH₂O)_n-CH₂COONa wherein n = 10-12 in the presence of methanol-aldehyde fraction as a low-temperature solvent representing waste in production of butyl alcohols. The process is carried out at temperature 80°C. Method provides enhancing effectiveness of dehydration and desalting degree of crude oil.

EFFECT: improved method for dehydration and desalting.

4 ex

Description

The invention relates to the field of application of anionic surfactants (ANPA) as an oil-soluble demulsifier, intended for use both in oilfield treatment plants and in oil refineries in the process of deep dehydration and desalting of crude oil.

Known methods for desalting and dehydrating oil using nonionic surfactants, which use polypropylene glycol ethers of polyethylene glycol or its derivatives with a molecular weight of 2500-10000 (USSR AS No. 171065, BI No. 10, 1965); polypropylene glycol derivatives of ethylene diamine or polypropylene glycol derivatives of ethylene glycol are proposed (AS USSR 168395, BI No. 4, 1965); the use of a mixture of oxyethylated synthetic fatty acids C ₁₀ -C ₂₅ (AS USSR No. 169166, BI No. 6, 1965); the use of hydroxyethylated fatty acids with a carbon number of more than 20 (USSR AS No. 137213, BI No. 7, 1961).

Of 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 ethoxylated fatty acids in hydrocarbon solvents; "Diproxamine 157-65M" according to TU 38.1011128-87 - nonionic surfactant, consisting of a block of copolymers of ethylene and propylene oxides based on ethylene diamine in a methanol solution; Reapon-4B is a non-ionic block copolymer of ethylene oxide and propylene with an average molecular weight of 4200, containing 27-31 hydroxyethyl units and 48-55 groups of propylene oxide in a solution of methanol and water.

Closest to the proposed technical solution is a method of destroying an oil emulsion using the following compositions: Reapon-4B demulsifier and additives of sodium, potassium salt of carboxymethylate of ethoxylated isononylphenol of the formula C ₉ H ₁₉ -C ₆ H ₄ -O (-CH ₂ -CH ₂ O) _n CH ₂ COOKt in their mass ratio (1-4): 1 (RU No. 2105789); an aqueous solution of an anionic surfactant based on the sodium salt of carboxymethylate of ethoxylated isononylphenol of the general formula C ₉ H ₁₉ -C ₆ H ₄ -O (-CH ₂ -CH ₂ O) _n CH ₂ COONa, sodium chloride, calcium chloride and a self-emulsifying organosilicon additive (RU No. 2244733 C1, RU No. 2245355 C1).

The aim of the invention is the use of an effective oil-soluble demulsifier based on AnPAV in 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, improve 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 low-temperature demulsifier, which is a solution of sodium salts of carboxymethylates of ethoxylated isononylphenols C ₉ H ₁₉ -C ₆ H ₄ -O (-CH ₂ -CH ₂ O) _n CH ₂ COONa, where n is 10-12 moles of ethylene oxide (TU 2484-088-05766565-2000), and the solvent is the methanol-aldehyde fraction (TU 2421-111-05766575-2003), butyl alcohol production waste.

A demulsifying additive is prepared by sequentially adding 50 g of a methanol-aldehyde fraction heated to a temperature of 40 ° C to 45 g of sodium salt of carboxymethylate of ethoxylated isononyl phenol, add 5 g of water and mix until a homogeneous solution is obtained.

The resulting demulsifier solution has the following characteristic:

- appearance light yellow liquid or light brown - density at 20 ° C, g / cm ³ , not less 0.930 - mass fraction of the active base,%, within 45-55 - pour point, ° C, not lower minus 40 - demulsifying ability,%, not less than 95 - degree of desalination,%, not less 65

The composition for dewatering and desalting the oil emulsion is used as follows: with a dosing pump, it is injected directly into the pipeline after the production well (pipe demulsification), and at the complex oil treatment plants, it is introduced into the feed line before mixing it with wash water.

заданной минерализации, щелочь (V_NaOH) и деэмульгатор (V_д). Содержимое эмульгируют на перемешивающем устройстве в течение 2-3 минут. После перемешивания делительную воронку с нефтяной эмульсией помещают в термостатирующую камеру с заданной температурой для проведения термохимического обезвоживания и обессоливания.In laboratory conditions, to determine the effectiveness of the demulsifying action of the compounds, the following methodology is used. Prepare a model emulsion. A predetermined amount of crude oil (V _n ) is poured into the separatory funnel, water is added

specified mineralization, alkali (V _NaOH ) and demulsifier (V _d ). 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 given temperature for thermochemical dehydration and desalination.

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 mass fraction of chlorides according to GOST 21534-76 and the residual moisture content according to GOST 14870-77, Dean-Stark method.

степени обессоливания (Х_с) одного и того же состава нефти и по содержанию нефтепродуктов в дренажной воде (С_н/п) при следующих условиях испытания:The effectiveness of demulsifiers is evaluated by demulsification ability

the degree of desalination (X _s ) 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

см³ - water volume

cm ³ 10 - the volume of a 2% solution of NaOH (V _NaOH ), cm ³ 0.2 - flow rate of a 1.0% demulsifier solution (V _d ), cm ³ 0.25 - temperature of thermal stabilization (t), ° C 80

в процентах рассчитывают по формулеDemulsification ability

percent calculated by the formula

- объем воды, взятый на приготовление нефтяной эмульсии, в примерах взято точно 10 см³;Where

- the volume of water taken to prepare the oil emulsion, in the examples taken exactly 10 cm ³ ;

- объем воды, выделившейся из эмульсии за 3 часа (см³).

- the amount of water released from the emulsion for 3 hours (cm ³ ).

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

where CC ref - the chloride content in the original oil (mg / DM ³ );

SS ost - the chloride content in the settled oil (mg / DM ³ ).

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

As can be seen from the above data, the effectiveness of the proposed composition of the demulsifier is higher than that of the known. The demulsification ability is 99.6%, and the degree of desalination is 67.7% with a consumption rate of 14 g / t (7 g / t in terms of AnPAW).

Oil losses with drainage water are minimal and amount to 258 mg / dm ³ , while for known demulsifiers this value is more than 1.5 times higher.

The method is illustrated by the following examples.

Example 1. The model emulsion is based on dehydrated Arlan oil, having the following characteristic:

- density, g / cm ³ 0.884 - chloride content (CC ex), mg / dm ³ 64 - sulfur content,% 1.9 - kinematic viscosity at 50 ° C, cSt 23.0

and water, the salinity of which is 60 mg / cm ³ . The stability of the emulsion obtained is determined by the above method without adding a demulsifier.

Example 2-4. A model emulsion is made up, as in example 1. Dehydration and desalination is carried out using demulsifiers:

Example 2 - known (industrial composition);

example 3 is a prototype;

Example 4 - Proposed.

Using the proposed invention will achieve a high degree of demulsification and desalting through the use of the proposed composition of the demulsifier, improve the state of wastewater generated during the separation of the emulsion, while reducing loss of oil product.

Table Comparative demulsifiers performance Example The name of the compounds The consumption of a 1.0% solution of demulsifier (Vd), cm ³ The specific consumption of the demulsifier, g / t of oil The moisture content in raw materials after heat treatment,% vol.

%Demulsification ability

% The chloride content in desalted raw materials (CC ost), mg / DM ³ The degree of desalination (XC),% Drainage characteristic hydrogen indicator (pH) content n / prod (Sn / p), mg / dm ³ one Without demulsifier 0 0 7 0 64 0 The separation of the emulsion into the aqueous and hydrocarbon phases is not observed 2 Diproxamine 157-65 0.25 fourteen 0.2 97.1 31.1 51,4 7.0 866 3 According to RU N2105789 with a mass ratio of 1: 1 0.25 fourteen 0.1 98.6 27,2 57.5 7.5 423 four Proposed 0.25 fourteen 0,03 99.6 20.7 67.7 7.5 258

Claims (1)

The method of dehydration and desalting of oil by introducing into the oil emulsion a demulsifying additive containing a solvent and an anionic surfactant (ANPA) - sodium salt of carboxymethylate of ethoxylated isononylphenol of the general formula C ₉ H ₁₉ -C ₆ H ₄ -O (-CH ₂ -CH ₂ O) _n CH ₂ COONa, where n is 10-12, characterized in that the methanol-aldehyde fraction (a waste product of butyl alcohols) is used as a low-temperature solvent and the process is carried out at a temperature of 80 ° C.