RU2272065C2 - Method of treating heavy petroleum to remove hydrogen sulfide - Google Patents

Abstract

FIELD: crude oil treatment.

SUBSTANCE: invention relates to removal of hydrogen sulfide and mercaptans from petroleum and gas condensate. Process is conducted through oxidation of impurities with air oxygen dissolved in petroleum under pressure up to 2.5 MPa at 20 to 70°C in presence of solution of ammonium salts of cobalt sulfophthalocyanines in 20-30% aqueous ammonia solution. Reagents are used in following amounts calculated per 1 mole hydrogen sulfide: 0.1-1.6 mole NH₄OH, 0.05-0.1 g phthalocyanine catalyst, and 0.05-0.1 m³ air. More specifically, ammonium salts of cobalt sulfo-, disulfo-, tetrasulfo-, dichlorodisulfo-, and dichlorodioxydisulfophthalocyanine are used. Part of exhausted ammonia catalyst solution is separated from cleaned raw material and returned into process.

EFFECT: minimized consumption of reagents and power, and enabled carrying out the process directly under oil-field conditions.

10 cl, 1 dwg, 2 tbl, 3 ex

Description

The invention relates to methods for purification of hydrocarbons from hydrogen sulfide and mercaptans and can be used in the gas and oil and oil refining industries.

In heavy sour crude, even after separation and stabilization, up to 0.06% (600 ppm) of hydrogen sulfide may be present. The presence of highly toxic hydrogen sulfide creates an unpleasant odor and environmental problems in the extraction, storage and transportation of oil. According to GOST R 51858-2002 “Oil. General specifications »the mass fraction of hydrogen sulfide in grade 1 oil should not exceed 0.002% (20 ppm).

In industry, alkalization is carried out to remove hydrogen sulfide, mercaptans and acid compounds from oil products (oil distillates and oils). When washed with aqueous solutions of alkalis, petroleum acids, phenols, hydrogen sulfide and low molecular weight mercaptans form water-soluble compounds and are removed with alkaline washing water. For alkalization using 2-12% NaOH solutions, one volume of liquid hydrocarbon is washed with 0.1-0.5 volumes of alkaline solution. For oil refining, this method is not used due to the formation of emulsions and the need for processing (regeneration) of a large volume of alkaline solutions. ["Chemistry of oil and gas" / Ed. Doctor of Technical Sciences Proskuryakova V.A. // L .: Chemistry. 1981, 358 pp.].

In the patent of the Russian Federation No. 2120464 ["A method for deodorizing purification of oil and gas condensate from hydrogen sulfide and low molecular weight mercaptans and installation for its implementation" / Shakirov F.G., Mazgarov A.M., Vildanov A.F. // BI 1998, No. 29, p. 352], a 25-45% aqueous solution of NaOH and a 0.15-0.25% solution of a phthalocyanine catalyst in 0.5 are simultaneously and continuously introduced into the flow of oil or gas condensate with stirring -1.5% aqueous alkali solution, then air is introduced into the feed stream, the resulting mixture is kept at a pressure of 0.5-3.0 MPa and a temperature of 25-65 ° C for 5-180 minutes, after which part of the reaction mixture containing purified raw materials, dissolved exhaust air and an emulsified aqueous-alkaline solution of the catalyst, is directed to mixing with the feedstock. Hydrogen sulfide in this method is oxidized to sodium thiosulfate.

The advantage of this method is the one-stage and simplicity of the process, as well as the return of the spent alkaline solution to the process for reuse. The disadvantages of the method are the increased consumption of reagents, the process under high pressure, prolonged (up to 180 min) exposure of the raw materials with dissolved air under such pressure and contamination of the purified raw materials with an spent alkali solution.

According to the technical nature and the achieved result, the closest to the proposed invention is a method for purifying oil and gas condensate from hydrogen sulfide by oxidation with atmospheric oxygen in the presence of 0.05-1.0% aqueous alkaline solution of a phthalocyanine catalyst. In this method, NaOH, ammonia and soda are used as the alkaline agent. 0.5-1.6 moles of an alkaline agent and 0.1-0.2 nm ^{3 of} air are taken per 1 mol of hydrogen sulfide. The mixture is kept under pressure of 0.3-1.5 MPa at a temperature of 20-70 ° C for 5-180 minutes. As the phthalocyanine catalyst used sodium salts of disulfo-, tetrasulfo-, dichlorodioxidisulfo- and cobalt polyphthalocyanine in an amount of 0.05-0.2 g per mole of hydrogen sulfide [US Pat. RF №2109033 dated 05/05/1996. "A method for purifying oil and gas condensate from hydrogen sulfide" / Shakirov F.G., Mazgarov A.M., Vildanov A.F., Khrushcheva I.K. // BI 1998, No. 11].

An alkaline version of this method, in which NaOH solutions and cobalt sulfophthalocyanine sodium salts are used, has now found practical application in the oil fields.

The disadvantages of this method are:

1. High consumption of expensive phthalocyanine catalyst (0.05-0.2 g per 1 mol or 34 g of H ₂ S). According to this method, when the content in oil is 500 ppm H ₂ S, the consumption of catalyst is 0.73-2.9 g per 1 ton of oil.

2. Large air flow: 0.1-0.2 nm ³ per 1 mol of hydrogen sulfide. When the content in oil is 500 ppm H ₂ S, the air flow rate is 1.47-2.94 nm ³ per 1 ton of oil. The greater the air consumption, the greater the amount of exhaust air emitted after oxidation and the greater the entrainment of light hydrocarbons with the exhaust air. The content of light hydrocarbons in the exhaust gases at 45 ° C is about 50%, that is, the entrainment of hydrocarbons with exhaust air is approximately equal to the amount of exhaust air.

воздуха. Для растворения такого количества воздуха в тяжелой нефти (плотность более 880 кг/м³) при 40-60°С необходимо давление 1,5-3,0 МПа. В известном способе максимальное давление равно 1,5 МПа.3. The known method does not allow to completely clean the raw material when it contains more than 420 ppm of hydrogen sulfide, since oxidation of 420 ppm H ₂ S requires

air. To dissolve such an amount of air in heavy oil (density more than 880 kg / m ³ ) at 40-60 ° C, a pressure of 1.5-3.0 MPa is necessary. In the known method, the maximum pressure is 1.5 MPa.

4. A water-alkaline solution of the catalyst in oil is introduced in an amount of 0.05-1%, therefore, in the case of the formation of a stable emulsion, the mass fraction of water in the refined oil can reach 1%. According to GOST R 51858-2002, the mass fraction of water in marketable oil should not exceed 0.5%.

The invention solves the following problems;

1. Reducing the consumption of phthalocyanine catalyst.

2. Reducing air consumption and reducing hydrocarbon losses (ablation) with exhaust air.

3. Reducing the mass fraction of water and salts in the refined oil.

4. The extension of the scope of the method for oil containing more than 420 ppm hydrogen sulfide.

5. The process of oxidation of hydrogen sulfide (we are talking about the same amount of hydrogen sulfide) at relatively lower pressures than in the known method.

To obtain the technical results in the proposed method for the purification of sour oil from hydrogen sulfide by oxidation with oxygen in the presence of aqueous alkaline solutions of phthalocyanine catalysts, 0.01-0.1% solutions of cobalt phthalocyanine ammonium salts of 20-30 are used as a catalyst solution % aqueous ammonia. The oxidation process is carried out at a temperature of 20-70 ° C and a pressure of up to 2.5 MPa.

Ammonia catalyst solution is introduced into the feedstock in an amount of 0.02-0.2%. The consumption of the phthalocyanine catalyst per 1 mol of hydrogen sulfide is 0.01-0.05 g; air - 0.05-0.1 nm ³ .

In the case of separation from the oil during settling, the aqueous ammonia solution of the catalyst is used repeatedly, that is, the spent solution after separation from the purified oil is strengthened with a fresh catalyst solution in a 20-30% ammonia solution and reused. In cases of the formation of an emulsion of spent catalyst solution and oil, this emulsion is returned to the process for reuse.

The exhaust air is separated from the purified raw material in two stages: in the first separator, the pressure is reduced to 0.2-0.6 MPa, in the second to 0.1-0.15 MPa.

Distinctive features of the proposed method are:

1. The use as a catalyst of solutions of ammonium (ammonium) salts of sulfonic acids of cobalt phthalocyanines in a 20-30% aqueous solution of ammonia. There are no data on the use of ammonium salts of cobalt sulfophthalocyanines in the patent and scientific literature.

2. In the proposed method for one mole of hydrogen sulfide take:

- phthalocyanine catalyst - 0.01-0.05 g - air - 0.05-0.1 nm ³

In the known method, the costs are:

- phthalocyanine catalyst - 0.05-0.2 g - air - 0.1-0.2 nm ³

In addition, in the proposed method, the aqueous-ammonia solution of the catalyst is taken in an amount of 0.02-0.2% to oil, and in the known method they take 0.05-1.0%, that is, 2.5-5 times more. Accordingly, the refined oil in the proposed method in the case of the formation of stable emulsions contains 2.5-5 times less water than in the known method.

Hydrogen sulfide in the presence of phthalocyanine catalysts in a slightly alkaline environment, including in ammonia solutions, is oxidized by the reaction:

0.5 mol or 16 g of oxygen is required per 1 mol of hydrogen sulfide. Hence, theoretically, air consumption is

where 0.231 is the mass fraction of oxygen in the air,%;

1.293 - air density, kg / m ³ .

Part of the hydrogen sulfide is neutralized by ammonia:

The resulting hydrosulfide dissolves in the spent aqueous solution and is removed with the spent aqueous ammonia solution.

Therefore, the lower limit of air consumption should be equal to 0.05 nm ³ per mole of hydrogen sulfide.

It is not necessary to inject more than 0.1 m ³ per 1 mol of hydrogen sulfide into air oil. With an increase in the amount of air introduced into the oil, the amount of exhaust air and the amount of light hydrocarbons carried away with the exhaust air increase, that is, oil losses increase.

In the known methods, strong alkalis (NaOH) are used or an alkaline agent is taken in large quantities (0.1-1.0% of the amount of oil). The solutions have a density of 1020-1150 kg / m ³ . In a strongly alkaline environment (pH> 12.5), hydrogen sulfide is oxidized to thiosulfate by the reaction:

Oxygen in the known methods is consumed twice as much, respectively, air consumption is required 2 times more.

Pressure limits of 0.3-2.5 MPa are established taking into account the solubility of air in oil. At pressures of 0.3 MPa, the solubility of air is 0.2-0.3 nm ³ per 1 m ^{3 of} oil, which at a flow rate of 0.1 nm ³ air per 1 mol of H ₂ S provides complete oxidation of 1-1.5 moles or 34 -51 ppm hydrogen sulfide. In cases of even lower concentrations of hydrogen sulfide in oil, there is simply no need for treatment, that is, the introduction of a treatment plant. For the dissolution of 0.5 nm ³ air in heavy oil (d≥880 kg / m ³ ), a pressure of about 0.6 MPa is necessary, for the dissolution of 1 nm ³ - about 1.3 MPa. For oxidation of 600 ppm or 17.647 moles of hydrogen sulfide, 0.882-1.765 nm ^{3 of} air is required, and for dissolving such quantities of air in oil, a pressure of 1.1-2.2 MPa is required. Therefore, the pressure of 2.5 MPa is taken as the upper limit. There is no need to increase pressure above 2.5 MPa.

In the present invention using 20-30% solutions of ammonia. High-sulfur heavy carbonic oils have a density of 880-900 kg / m ³ . Concentrated 20-30% ammonia solutions have a density of 900-910 kg / m ³ . The closer the density of oil and aqueous solutions, the easier it is to create a homogeneous emulsion of a water-alkaline solution of the catalyst in oil. Therefore, in the proposed method, more efficient mixing is achieved. In addition, 25-28% ammonia solutions are produced by Russian industry.

The required catalyst consumption is established on the basis of experiments. Consumption below 0.01 g per 1 mol of H ₂ S does not provide the necessary oxidation rate, and there is no need to increase the amount of expensive catalyst (price of 1 g 2-3 rubles) above 0.05 g per 1 mol of H ₂ S.

In the known methods, sodium salts of cobalt sulfophthalocyanines are used, which are not stable in highly alkaline solutions (pH> 13.5) at 40 ° C and quickly decompose. Therefore, increased amounts of phthalocyanine catalysts are forced into alkaline solutions. In the proposed method, ammonium salts of cobalt sulfophthalocyanines dissolved in an aqueous solution of ammonia with a pH of <12.5 are used. In such solutions, the stability of ammonium salts is almost 10 times higher than the stability of sodium salts in the known method. Therefore, the consumption of the phthalocyanine catalyst is 4-5 times lower than in the known method.

Ammonium salts of cobalt phthalocyanines sulfonic acids are obtained by dissolving the corresponding sulfonic acids in a 20-30% ammonia solution or by dissolving the sodium salts of sulfonic acids in a 20-30% ammonia solution in the presence of ammonium chloride - NH ₄ Cl by the reaction:

RSO ₃ Na + NH ₄ Cl → RSO ₃ NH ₄ + NaCl

0.01-0.1% solutions of ammonium salts of sulfophthalocyanines can be prepared in one step, but from the point of view of technology it is more rational to first prepare concentrated 1.5 ± 0.5% solutions of ammonium salts of sulfophthalocyanines, then dilute these solutions to working concentration of 0.01-0.05%. To dissolve the powdered sulfonic acids of phthalocyanines, their sodium salts and ammonium chloride, an apparatus (reactor) with mechanical stirring is required, for complete dissolution, a stirring time of 20-30 minutes is required, and for diluting concentrated solutions 100 times with aqueous ammonia, stirring by circulation with a circulation pump in any capacities. To prepare a concentrated solution, you can use a reactor with a small mechanical stirrer. In this embodiment, capital and energy costs will be less than in the case of installing large reactors with a mechanical stirrer to prepare 0.01-0.05% catalyst solutions in one go.

At 45-70 ° C, hydrogen sulfide is completely oxidized in 15-30 minutes, and there is no need to increase the temperature above 70 ° C. At 18-20 ° C, a reaction time of about 1.5 hours is required to complete the reaction. The limitation of the lower temperature limit of 20 ° C is associated with a slowdown in the reaction rate and an increase in the viscosity of oil, which makes it difficult to emulsify the ammonia solution of the catalyst in oil.

The two-stage separation of exhaust air by reducing the pressure in the first separator to 0.2-0.6 MPa and in the second separator to 0.1-0.12 MPa gives the following positive effects:

1. The losses of light hydrocarbons carried away with the exhaust air released from oil are reduced, since the main amount of exhaust air is emitted (separated) in the first separator when the pressure decreases, for example, from 2 to 0.6 MPa or from 1 to 0.2 MPa . When separating under a pressure of 0.2-0.6 MPa, the gas phase contains hydrocarbon vapors significantly less than in the case of separation of exhaust air at atmospheric pressure.

2. During the evaporation of exhaust air from oil with a decrease in pressure to 0.2-0.6 MPa, nitrogen is mainly released, and oxygen remains in solution, since the solubility of oxygen in oil is almost 2 times higher than the solubility of nitrogen. Oxygen remaining in oil in dissolved form continues the oxidation of H ₂ S in the separators. As a result, a more complete purification of oil from hydrogen sulfide is achieved.

The proposed method of oil refining is simple to implement and can be implemented in oil fields and refineries.

The proposed method is illustrated by the attached technological scheme (see drawing) and examples of its implementation.

In the tank T-1, a catalyst solution is prepared by dissolving 0.02% ammonium chloride and 0.04% cobalt disulfophthalocyanine disodium salt, and a cobalt disulfophthalocyanine diammonium salt solution is obtained.

Oil that has undergone preparation (separation, desalination, dehydration) and contains 300-600 ppm hydrogen sulfide with a temperature of 20-65 ° C (preferably 40-55 ° C), enters the buffer tank E-1. From this tank, pump N-1 delivers oil at a pressure of 0.3-2.5 MPa to the oxidation reactor of the column type R-1. The calculated amount (preferably 0.5-1.0 kg / t) of a solution of a phthalocyanine catalyst in ~ 25% aqueous ammonia solution is fed to the inlet of the pump N-1 from the tank E-4 by the ND metering pump. Compressed air, which dissolves in oil, is supplied to the oil stream after pump N-1 by compressor K-1 under a pressure of 0.4-2.5 MPa. Next, the mixture enters the reactor R-1 column type. In the reactor, hydrogen sulfide is oxidized with oxygen dissolved in oil air:

After the reactor, oil enters the C-1 separator, where the pressure drops to 0.20-0.5 MPa, and the main part of the exhaust air is separated from the oil. Then the oil enters the second separator C-2, where the pressure decreases to atmospheric, and the remaining part of the exhaust air is separated. In the separators C-1 and C-2, part of the spent catalyst solution is separated from the refined oil in the form of an emulsion. According to the technological scheme, it is possible to return this emulsion to mixing with crude oil.

Most oils form emulsions when mixed with alkaline solutions. The resulting salts of naphthenic acids are emulsifiers. The higher the ratio of hydrocarbon feed: ammonia solution, the greater the concentration of naphthenates in the aqueous phase and the higher the stability of the resulting emulsion. Heavy carboxylic oils, which contain a lot of naphthenic acids, form persistent, difficult to separate emulsions. Of these oils, the spent aqueous ammonia solution usually settles in the form of an emulsion containing 3-30% water. Upon sedimentation, three layers are formed: at the top is a layer of purified raw materials, at the bottom is a layer of an aqueous solution and in the middle is an emulsion layer. For the complete separation of the emulsion by settling, it takes time from several hours to several days. The presence of salts and temperature increase accelerate the process of separation of the emulsion. In the proposed method, the method of returning the emulsion of the spent solution and oil to the oxidation process described in RF patent 2120464 is used, i.e. mix it with the feedstock. The return of the catalyst solution for reuse allows you to save the consumption of catalyst and ammonia.

Part of the spent alkaline solution in the case of settling it from oil in the separator C-2 is periodically removed from the process. The spent solution can be disposed of by mixing with produced water, followed by their injection into the formation. The volume of produced water is 10-1000 times greater than the volume of spent alkaline solutions, so adding them to produced water does not change the composition of the latter.

The proposed method is tested in laboratory conditions.

Example 1. Prepare solutions of various sulfonic acids (mono-, di - and tetra) cobalt phthalocyanines in a 20-30% solution of ammonia. Phthalocyanine sulfonic acids are introduced at the rate of obtaining 0.01-0.05% of ammonium salts. The resulting solutions are used as a catalyst solution. A weighed portion of the catalyst solution is taken into a flask with a capacity of 120 ml, 30-45 g of oil cooled to -5-0 ° С are added, the air space of the flask is filled with oxygen (70-87 ml). The flask is closed with a rubber stopper and at a temperature of 20-65 ° C, give exposure to stirring with shaking for 15-90 minutes. When chilled oil is heated, an overpressure is created in a closed flask. According to the content of dissolved oxygen in oil, these experiments simulate the processes of oxidation by oxygen of air dissolved under a pressure of 0.6-0.9 MPa, which, according to calculations, corresponds to 0.05-0.1 nm ^{3 of} air per mole of H ₂ S. After exposure 15 min samples of oil (~ 0.5 ml) are taken from the flask with a syringe for analysis, after another 30-60 minutes a second sample is taken. Analyze samples for the content of hydrogen sulfide by potentiometric titration according to GOST 17323-76. In the experiments of table 1, ammonium salts of the following phthalocyanine catalysts were used:

- cobalt phthalocyanine sulfonic acid (CFC);

- cobalt phthalocyanine disulfonic acid (DSFC);

- cobalt phthalocyanine tetrasulfonic acid (TSPA);

- cobalt phthalocyanine dioxidichlorodisulfonic acid (DODHDSFK);

- cobalt phthalocyanine dichlorodisulfonic acid (DCSFC).

Example 2. The first two experiments are carried out, as in example 1. After oxidation, the purified oil in experiment No. 2 is separated from the exhaust air and mixed with the next portion of the oil to be purified in a ratio of 1: 1. In this mixed portion of oil in experiment No. 3, the same amount of catalyst solution is introduced as in experiment No. 1, then the oxidation process is carried out as in example 1. The purified oil after experiment No. 3 is divided into two equal parts, one part of 25 g is mixed with such the same amount of crude oil and the mixture is used in experiment No. 4. The following experiment No. 5 is carried out similarly to experiment No. 4. In experiment No. 6, the amount of refined oil for the preparation of a mixture of oils is taken in half. The results of the experiments are given in table.2. The degree of oil purification (X,%) from hydrogen sulfide is calculated by the formula:

where H ₂ S _Ref - mass fraction of hydrogen sulfide in the original crude oil,%;

H ₂ S _purification - mass fraction of hydrogen sulfide in purified oil,%.

Discussion of the results of the experiments in examples 1 and 2

From literature data it is known that the rate of oxidation of hydrogen sulfide in an alkaline medium is 3-4 orders of magnitude higher than in an acidic medium. Therefore, the amount of ammonia introduced into the oil should be sufficient to create an alkaline environment. As can be seen from table 1, the rate of oxidation of hydrogen sulfide with increasing amount of introduced ammonia, that is, the ratio of NH ₃ : H ₂ S, significantly increases (experiments No. 1, 2 and 13). Hydrogen sulfide can also be oxidized without the use of phthalocyanine catalysts ”, however, in this case, a large consumption of ammonia is required (experiment No. 2).

The introduction of 0.25% ammonium salt DODHDSFK in an aqueous solution of ammonia reduces the concentration of H ₂ S in the purified product by almost half (experiments No. 3 and 4). The greater the amount of introduced catalyst, the higher the degree of purification of raw materials from hydrogen sulfide (experiments No. 4-6). However, the introduction of large quantities of expensive phthalocyanine catalyst is not economically viable. Optimal for the oxidation of hydrogen sulfide is a temperature of 40-60 ° C. The process can be carried out at 20-30 ° C, but in these cases either a long oxidation time (experiment No. 11) or a large consumption of ammonia (experiment No. 12) are required. In experiments No. 4-12, in which the process parameters are within the range proposed in the invention, the content of H ₂ S in the refined oil after 30 minutes of oxidation with a sufficient amount of oxygen does not exceed the established norms of 20 ppm.

In experiments No. 14 and 15, where a catalyst solution with a low concentration of ammonia is used, satisfactory results are achieved, but with a high consumption of ammonia. In experiment No. 13, where a dilute ammonia solution is used and the amount of ammonia is below 0.5 moles per mole of hydrogen sulfide, the required degree of purification is not achieved.

In the known method (experiment No. 16), the required degree of purification is achieved, but with a high consumption of ammonia and a 2–3 times higher consumption of the catalyst — cobalt disulfophthalocyanine disodium salt (DSFC-Na).

As can be seen from table 2 (experiment No. 1), when 0.605 moles of ammonia and 0.02 g of ammonium salt DODHDSFK are added to oil per 1 mol of hydrogen sulfide in 20 minutes at 50 ° C, the mass fraction of H ₂ S in oil decreases from 420 to 83 ppm To clean the oil to an H ₂ S content of 20 ppm, the consumption of NH ₃ and the phthalocyanine catalyst is twice as high (experiment No. 2). In experiments No. 3-5 in the case of mixing the original crude oil with purified oil in a mass ratio of 1: 1, satisfactory purification of the mixture is achieved at the same ammonia and phthalocyanine catalyst costs as in experiment No. 1. A decrease in the amount of refined oil taken for mixing, respectively, a decrease in the amount of spent catalyst solution returned with refined oil leads to a deterioration in the quality of refining (experiment No. 6).

Thus, the return of part of the spent catalyst solution or its emulsion with refined oil makes it possible to reduce (save) the costs of aqueous ammonia and phthalocyanine catalyst.

Example 3. The experiments are carried out as in example 1. Take 75 ml of oil and 45 ml of air and 0.2 g of a catalyst solution containing 0.018% of the catalyst, which is 0.05 g of catalyst per mole of hydrogen sulfide. A solution containing the ammonium salt of DSFC in a 20% ammonia solution is introduced into the first flask, and a solution of the sodium salt of DSFC in a 20% alkali solution (as in the known method) is introduced into the second flask. The oxidation of 355 ppm H ₂ S to S by reaction of 1 per 1 ton of oil requires at least 177.5 g of O ₂ or 0.598 nm ^{3 of} air. The oxidation of H ₂ S in 75 ml or 67.5 g of oil requires at least 40 ml of air. Air consumption per mole of H ₂ S is 0.06 nm ³ . The oxidation is carried out at 50 ° C for 60 minutes According to the analysis in flask No. 1 - H ₂ S - less than 10 ppm, in flask No. 2 - 132 ppm. This is explained by the lack of oxygen in experiment No. 2 due to the oxidation of H ₂ S to thiosulfate.

After that, the space above the oil in flask No. 2 was purged with fresh air, mixed and allowed to hold for another 60 minutes. Carry out an oil analysis; H ₂ S content = 16 ppm. So, for the oxidation of H ₂ S in experiment No. 2, air is required almost 2 times more.

The more air is taken for oxidation, the more exhaust air is generated containing 50-70% hydrocarbons. Therefore, in the inventive method, the loss of hydrocarbons is less than in the known method.

table 2
The results of the experiments in example 2 No. The number of oils in the mixture, g H ₂ S _ref , ppm The amount of catalyst solution,% The ratio of newly introduced reagents to 1 mole of hydrogen sulfide Oxidation temperature, ° С H ₂ S _purification , ppm, after 20 min of oxidation uncleaned. cleared. uncleaned. oil oil mixture in uncleaned. oil in a mixture of oils

моль/моль

mol / mol

g / mol one 25 - 420 - 0,054 0,054 0.605 0.02 45 83 2 25 - 420 - 0.108 0.108 1.21 0.04 45 twenty 3 25 25 420 220 0,054 0,027 0.60 0.02 45 eighteen four 25 25 420 219 0,054 0,027 0.60 0.02 45 24 5 25 25 420 222 0,054 0,027 0.60 0.02 45 twenty 6 25 12.5 420 321 0,054 0,040 0.60 0.02 45 33

Claims (10)

1. The method of purification of heavy sour crude oil from hydrogen sulfide by oxidation with atmospheric oxygen in the presence of aqueous-alkaline solutions of cobalt sulfonated phthalocyanines at a temperature of 15-70 ° C under pressure, characterized in that solutions of cobalt phthalocyanine ammonium salts of 20- are used as a catalyst solution 30% aqueous ammonia; 0.05-0.1 nm ^{3 of} air and 0.01-0.05 g of ammonium salt of cobalt phthalocyanine sulfonic acid are taken per mole of hydrogen sulfide. 2. The method according to claim 1, characterized in that 0.01-0.1% solutions of ammonium salts of cobalt phthalocyanines sulfonic acids are used. 3. The method according to claims 1 and 2, characterized in that the catalyst solution is introduced into the oil in an amount of 0.02-0.2%. 4. The method according to claim 1, characterized in that the use of ammonium salts of mono, - di, - tetrasulfonic acid, dichlorodisulfonic acid and dichlorodioxydisulfonic acid cobalt phthalocyanine. 5. The method according to claims 1 and 4, characterized in that the catalyst solution is obtained by dissolving the sodium salts of cobalt sulfophthalocyanines and ammonium chloride in an aqueous solution of ammonia. 6. The method according to claim 1, characterized in that the catalyst solution after oxidation of hydrogen sulfide is separated from the refined oil and used repeatedly. 7. The method according to claim 1, characterized in that the emulsion of the spent catalyst solution and oil are separated from the purified oil and mixed with the crude oil. 8. The method according to claim 1, characterized in that the process is carried out under a pressure of 0.3-2.5 MPa. 9. The method according to claim 1, characterized in that the separation of exhaust air from the refined oil is carried out in two stages: in the first separator, the pressure is reduced to 0.2-0.6 MPa, in the second separator to 0.1-0.15 MPa . 10. The method according to PP.2, 5, characterized in that first they prepare concentrated 1-2% solutions of ammonium salts of sulfophthalocyanines, then these solutions are diluted with an aqueous solution of ammonia to the content of ammonium salts of 0.01-0.1%.