RU2698793C1 - Method of purifying liquefied hydrocarbon gases from molecular sulphur, sulphur compounds and carbon dioxide - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention can be used in oil, gas, gas processing, oil refining, petrochemical, chemical and other industries. Method comprises mixing liquefied hydrocarbon gases, which are a hydrocarbon liquid, with an absorbent containing sulphides and / or polysulphides, to form, after completion of mixing, a two-phase layer consisting of an absorbent aqueous layer containing said components extracted from the purified hydrocarbon liquid, and a layer of purified hydrocarbon fluid with reduced content of said components. Absorbent used is an aqueous solution of ethanolamine with concentration of 18–72 wt%, containing water-soluble sulphides and / or polysulphides, selected from: sulphides and / or polysulphides of alkali, alkali-earth metals, ammonium, as well as ethanolamines, wherein content of sulphides and / or polysulphides in water solution of ethanolamine is not less than 0.05 wt%. Mixing of liquefied hydrocarbon gases with absorbent is carried out in an amount required for formation after completion of mixing of absorbent water layer, containing molecular sulphur extracted from purified hydrocarbon liquid, sulphur compounds and carbon dioxide, and a layer of hydrocarbon fluid with no or low content of molecular sulphur, sulphur compounds and carbon dioxide, which is then decanted from the aqueous layer of the absorbent to obtain a purified product.

EFFECT: high efficiency of extracting molecular sulphur simultaneously with sulphur compounds and carbon dioxide to obtain a product purified to required standards, as well as reducing capital and operating costs.

4 cl, 8 tbl, 8 ex

Description

The invention relates to the purification of liquefied hydrocarbon gases (in particular, a wide fraction of light hydrocarbons (BFLH), ethanized wide fraction of light hydrocarbons (ESHLF), liquefied propane-butane fraction, gas stable gasoline (BHS) and other hydrocarbon fractions immiscible with absorbent) from undesirable harmful components, such as: molecular sulfur, sulfur compounds (in particular, from hydrogen sulfide and mercaptans) and carbon dioxide, and can be used in oil, gas, gas processing, eftepererabatyvayuschey, petrochemical, chemical and other industries.

During processing, various sulfur compounds and carbon dioxide, as well as molecular sulfur, the content of which in liquefied hydrocarbon gases can range from trace amounts up to 50 ppm or more, can get into liquefied hydrocarbon gases from raw gas (associated petroleum gas or natural gas). These harmful components, in addition to molecular sulfur, can be removed or reduced to the required level by existing technologies using solutions of ethanolamines. However, it was experimentally established that a pure solution of ethanolamine without the use of special additives (activators, inhibitors) does not have the ability to purify liquefied hydrocarbon gases from dissolved molecular sulfur. In addition, molecular sulfur, which is contained in liquefied hydrocarbon gases containing hydrogen sulfide (even in small concentrations that do not require purification) and carbon dioxide, is of particular complexity. The presence of molecular sulfur, sulfur compounds and carbon dioxide leads to the problem of corrosion in the transport of liquefied petroleum gases and is unacceptable in such quantities when it is processed into gas chemistry products (pyrolysis, catalytic processes).

Due to the presence of molecular sulfur and sulfur compounds, liquefied hydrocarbon gases often do not pass the tests according to GOST 6321-92 “Test method on a copper plate”, as well as ISO 6151 “Liquefied petroleum gases. Corrosive effect on copper. Method using a copper strip ”and ASTM D 1838-07“ Standard Test Method for Corrosion of Striped Copper in a Liquefied Petroleum Gas Medium ”.

The most clear idea of the molecular sulfur content in liquefied hydrocarbon gases is given by the study (see D.V. Panteleev, S.V. Meshcheryakov, I.V. Sukhilina, D.V. Elyutin “Study of the effect of sulfur compounds in liquefied hydrocarbon gases on the quality product during transportation ”, J.“ Gas industry, No. 8, 2012, pp. 70-73), which established that when the sulfur content in liquefied hydrocarbon gases is more than 5 ppm, the quality of liquefied hydrocarbon gases no longer corresponds to the first class when tested on a copper plate and this videtelstvuet increased corrosivity of hydrocarbon medium. Therefore, the purification of liquefied hydrocarbon gases from molecular sulfur is a serious problem in their preparation for transport and processing.

In addition, in most regulatory documents for liquefied petroleum gases (except ESLFL) there is no limit on the content of carbon dioxide, which does not exclude the possibility of the presence of carbon dioxide in these products. The carbon dioxide content in ESFLU in some cases can reach several percent at a rate of 0.03% wt. (TU 38.101524-93, change No. 7).

The foregoing indicates in favor of the need to purify all types of liquefied hydrocarbon gases from molecular sulfur, sulfur compounds and carbon dioxide.

A known method of purification of hydrocarbon gas from acidic components (see RF patent for the invention No. 2069081, B01D 53/14, publ. 11/20/1996), including the absorption of acidic components by a solution of alkanolamine in the presence of an alkanolamine corrosion inhibitor, which is used as alkanolamine polysulfides, previously treated with inorganic sulfides and / or polysulfides, while the concentration of the corrosion inhibitor is maintained within the range of 0.01-0.4 g / l of absorbent solution (~ 0.01-0.04% wt.).

The disadvantage of this method is the possibility of its use only for the purification of hydrocarbon gas and only from such acidic components as hydrogen sulfide and carbon dioxide. In addition, the known method is unsuitable for purification from molecular sulfur, and the alkanolamine polysulfides used in it at the indicated concentration are used primarily as corrosion inhibitors.

A known method of purification of light hydrocarbon fractions containing sulfur compounds and carbon dioxide (see RF patent for the invention No. 2492213, C10G 21/20, C10G 19/02, C10G 19/08, publ. 09/10/2013), comprising contacting the hydrocarbon liquid with a circulating aqueous alkanolamine solution, modified with alkali in an amount of 0.0005-1%.

The disadvantage of this method is the low (15 wt.%) Concentration of alkanolamine, the absence of sulfides and polysulfides in the initial absorbent and the insignificant content of an activating additive in the absorbent (0.0005-1% sodium hydroxide from the mass of the absorbent solution), which together does not allow cleaning hydrocarbon liquid from molecular sulfur if present in the feed.

The closest in technical essence and the achieved result is a method of removing molecular sulfur from hydrocarbon liquids, in which the cleaning of hydrocarbon liquids from molecular sulfur is carried out using an aqueous alkali solution containing water-soluble metal sulfides (see US patent No. US 5,160,045).

The disadvantage of this method is the possibility of its use only for the purification of hydrocarbon liquids, previously pre-purified from impurities such as carbon dioxide and hydrogen sulfide. Those. the main direction of the use of the known method is only the purification of the hydrocarbon liquid from molecular sulfur. If the cleaned hydrocarbon liquid also contains acidic components (hydrogen sulfide, mercaptans and carbon dioxide), poorly regenerated sulfides and carbonates of alkali metals will form as a result of chemical reactions, while the pH of the aqueous solution decreases and it loses the ability to extract sulfur from the hydrocarbon liquid therefore, the efficiency of the process will decrease. In addition, in the presence of acidic components in the hydrocarbon liquid being purified, the use of the known method is also impractical due to unreasonably high alkali consumption and the appearance of a large amount of alkali-sulfur effluents.

The technical task of the invention is the creation of an effective method of purification of liquefied hydrocarbon gases from molecular sulfur, sulfur compounds and carbon dioxide, as well as reducing capital and operating costs.

The technical result consists in increasing the efficiency of molecular sulfur recovery simultaneously with sulfur compounds and carbon dioxide to obtain a product purified to the required standards, as well as reducing capital and operating costs.

The specified technical result is achieved by the fact that in the claimed method of purification of liquefied hydrocarbon gases from molecular sulfur, sulfur compounds and carbon dioxide, comprising mixing liquefied hydrocarbon gases with an absorbent containing sulfides and / or polysulfides, with the formation after mixing of a two-phase layer consisting of an aqueous a layer of absorbent material containing said components extracted from a purified hydrocarbon liquid, and a layer of purified hydrocarbon liquid with a low content of of these components, it is new that an absorbed solution of an increased concentration of ethanolamine containing water-soluble sulfides and / or polysulfides selected from the series: sulfides and / or polysulfides of alkali, alkaline earth metals, ammonium, and ethanolamines is used as absorbent, while mixing liquefied hydrocarbon gases with an absorbent are carried out in an amount necessary for the formation, after completion of mixing, of an aqueous layer of an absorbent containing a mole extracted from the purified hydrocarbon liquid angles to sulfur, sulfur compounds and carbon dioxide, and a layer of hydrocarbon liquid with no or low content of molecular sulfur, sulfur compounds and carbon dioxide, which is then decanted from the aqueous layer of the absorbent to obtain purified product.

In addition, ethanolamines in an aqueous solution are selected from the series: monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA), in an amount of 18-72% by weight, and the concentration of sulfides and / or polysulfides in an aqueous solution of ethanolamine is not less than 0.05% wt.

In addition, activating additives, for example, alkali metal hydroxides in an amount of not more than 5 wt%, can be introduced into the absorbent composition. or phase transfer catalysts, such as: quaternary ammonium salts, phosphonium salts, in an amount up to 1% wt.

The use of an absorbent for cleaning a hydrocarbon liquid, consisting of an aqueous solution of ethanolamine (MEA, DEA, MDEA) of an increased concentration of 18-72% wt. and containing water-soluble sulfides and / or polysulfides in an amount of not less than 0.05% by weight, helps to remove molecular sulfur from a hydrocarbon liquid simultaneously with sulfur compounds and carbon dioxide.

Upon contact of aqueous solutions of ethanolamines containing water-soluble sulfides and / or polysulfides with a hydrocarbon liquid, the molecular sulfur dissolved in it reacts with sulfides and / or polysulfides to form water-soluble polysulfides, which are concentrated in the aqueous phase. Acid gases dissolved in a hydrocarbon liquid also react with ethanolamines. As a result, the aqueous phase is enriched with polysulfides, hydrosulfides and bicarbonates, and the hydrocarbon liquid is purified from molecular sulfur, sulfur compounds and carbon dioxide. The resulting two-phase mixture is then stratified into a layer of hydrocarbon liquid in which the content of molecular sulfur, sulfur compounds and carbon dioxide is absent or is present in a reduced amount, and also into the aqueous absorbent layer containing molecular sulfur, sulfur compounds and carbon dioxide extracted from the hydrocarbon liquid. As a result of subsequent decantation of the obtained hydrocarbon liquid layer from the aqueous absorbent layer, a product is obtained that meets the requirements for purified products.

The inventive combination of features of the method allows to purify liquefied hydrocarbon gases in which the molecular sulfur content varies widely: from a concentration close to saturation, to residual values comparable with the sensitivity of analytical control methods. The rate of removal of molecular sulfur, as well as other pollutants, from the cleaned hydrocarbon liquid is determined by mass transfer from the hydrocarbon phase to the aqueous phase. Therefore, the contact time to achieve the required degree of purification can vary widely depending on a number of factors (the nature of the hydrocarbon fraction, the concentration of contaminants, the concentration of ethanolamine and sulfide and / or polysulfide in the solution being cleaned, temperature, phase ratio), and mainly on mixing conditions hydrocarbon and aqueous phases, and range from several minutes to several hours. Thus, by varying the time and method of contact, the phase ratio, the concentration of sulfides and / or polysulfides in an aqueous solution of ethanolamine, a decrease in the concentration of contaminants in the purified hydrocarbon liquid to the required values is achieved.

Introduction to the composition of the absorbent as an activating additive of alkali metal hydroxides in an amount of not more than 5% wt. helps to increase the efficiency and intensification of the cleaning process of liquefied petroleum gases having a high content of acidic components (for example, carbon dioxide more than 2% wt., hydrogen sulfide more than 0.05% wt.), due to the greater reaction rate with these compounds.

Introduction to the absorbent composition of phase transfer catalysts in an amount of not more than 1% wt. It helps to increase the efficiency and intensification of the process of purification of liquefied hydrocarbon gases having a high content of acidic components (see above) by accelerating the exchange and interaction of reacting substances between the hydrocarbon and aqueous phases. As phase transfer catalysts, triethylbenzylammonium chloride (TEBAH), tetrabutylammonium bromide (TBAB), trioctylmethylammonium chloride (TOMAX) and others, including quaternary phosphonium salts (see Ostrovsky VA, “Interphase Catalysis of Organic Reactions,” can be used). in the Sorov educational journal, volume 6, No. 11, 2000, pp. 30-34).

In addition, the use of the proposed method allows to reduce capital and operating costs for the purification of liquefied petroleum gases, which simultaneously contain molecular sulfur, sulfur compounds and carbon dioxide, since in accordance with the proposed method, the purification is carried out in one stage, while the purification Known methods are carried out using two or more separate purification steps.

Also, the proposed method allows for reliable protection of equipment and pipelines from corrosion and thereby reduce capital and operating costs of production.

The method is as follows.

The conditions for the process of purification of liquefied petroleum gases:

Liquefied hydrocarbon gases (e.g., BFLH or ESFLD) are mixed with an absorbent containing an aqueous solution of ethanolamine (e.g., MEA) into which water-soluble sulfides and / or polysulfides (e.g., sodium sulfide or ethanolamine polysulfide) have been previously added.

The mixture of the hydrocarbon liquid with the absorbent is carried out by physical mixing. The absorbent solution can be dispersed into a cleanable hydrocarbon liquid using any effective mixing (mass transfer) device.

As a result of chemical reactions, water-soluble compounds of elemental sulfur are formed (including polysulfides), as well as hydrosulfides, bicarbonates and carbonates.

When a two-phase mixture is stratified, a layer of hydrocarbon liquid is formed with no or reduced content of molecular sulfur, sulfur compounds and carbon dioxide, as well as an aqueous absorbent layer containing molecular sulfur, sulfur compounds and carbon dioxide extracted from the purified hydrocarbon liquid.

The hydrocarbon layer is then decanted from the aqueous absorbent layer to obtain a purified product, and the aqueous absorbent layer, depending on the degree of saturation with molecular sulfur, sulfur compounds and carbon dioxide, is either sent to the processing of new portions of the crude hydrocarbon liquid or to regeneration from acidic components.

Separation of the emulsion formed by mixing the hydrocarbon liquid with the absorbent, settling of the emulsion to separate the aqueous layer of the absorbent and the hydrocarbon liquid layer, as well as decantation can be carried out using any known methods and existing effective phase separation devices.

The regeneration of a saturated absorbent solution is carried out at a temperature not exceeding 120 ° C using known standard methods for the regeneration of alkanolamine solutions.

A regenerated absorbent solution containing water-soluble sulfides and / or polysulfides is returned to the hydrocarbon liquid purification process. The regenerated solution is periodically adjusted according to the concentration of ethanolamine and water-soluble sulfide and / or polysulfide. When a significant amount of sulfur and other non-regenerable compounds are accumulated in the absorbent solution, their removal is carried out by distillation of the absorbent in the reclaimer according to existing methods.

As a result of purification with the indicated parameters, the residual content of harmful components in the purified hydrocarbon liquid is:

The specified content of harmful components in purified liquefied hydrocarbon gases meets the requirements for hydrocarbon fluids given in the relevant TU and GOST, and provides indicators for class 1 when tested on a copper plate.

The following examples illustrate the invention.

Example 1

To assess the effect of the concentration of ethanolamine on the degree of purification of a hydrocarbon liquid from molecular sulfur, experiments were performed on the purification of hexane with an aqueous solution of ethanolamine of various concentrations containing 1% wt. sodium sulfide (Na ₂ S).

Experimental conditions:

The purified hydrocarbon liquid is hexane, the test temperature is 40 ° C, the time is 30 minutes, the ratio of the phases “hydrocarbon: absorbent” is 3: 1. Table 1 shows the experimental results.

As follows from table 1, the effective purification of liquid hydrocarbons from molecular sulfur for ethanolamines MEA, DEA and MDEA is ensured at a concentration of ethanolamines of 18-72% by weight, which corresponds to 3N - 6N solutions for each ethanolamine.

Example 2

To assess the effect of the concentration of sulfides or polysulfides on the degree of purification of a hydrocarbon liquid from molecular sulfur, experiments were performed on the purification of hexane 24% wt. MEA solution containing various concentrations of sulfides or polysulfides.

Experimental conditions:

The purified hydrocarbon liquid is hexane, the test temperature is 40 ° C, the time is 30 minutes, the ratio of the phases “hydrocarbon: absorbent” is 3: 1. Table 2 shows the experimental results.

As follows from table 2, 24% wt. MEA solution without activating additives (sulfides, polysulfides) does not have the ability to purify the dissolved hydrocarbon liquid from hydrocarbon liquid (experiment No. 1). Sulfides and polysulfides of MEA with a concentration of 0.05% wt. under experimental conditions, hexane is not sufficiently purified of molecular sulfur (experiments No. 2, 3). Sulfides and polysulfides of MEA with a concentration of more than 0.2% wt. under the conditions of the experiment, hexane is purified from molecular sulfur to the required values (experiments No. 4-12).

Example 3

In this example, the following polysulfide compositions (PS) were prepared:

- PS (A): 15% wt. a solution of MEA polysulfides (in terms of sulfur) in a commodity MEA;

- PS (B): 15% wt. MEA polysulfide solution (in terms of sulfur) + 5% wt. sodium hydroxide in the marketed MEA;

- PS (C): 15% wt. MEA polysulfide solution (in terms of sulfur) + 1% wt. sodium sulfide in commercial MEA.

Experimental conditions:

The cleaned hydrocarbon fluid is hexane, containing from 54 to 82 ppm molecular sulfur. Absorbent - 24-30% of May. MEA solution with additives of amine polysulfides (polysulfide compositions PS (A), PS (B), PS (C)), sodium sulfide and potassium sulfide without additives. The ratio of the phases "hydrocarbon: absorbent" is 3: 1. The temperature of the experiments is 40 ° C.

The tests were carried out in a temperature-controlled bath in a three-necked flask equipped with a thermometer, reflux condenser and mechanical stirrer. A measured amount of purified hydrocarbon liquid and a measured amount of absorbent were placed in the flask, then stirring was turned on. Periodically (every 10 min), the stirring was stopped and a sample of the hydrocarbon liquid was taken for analysis. After analysis of molecular sulfur, the sample was returned to the flask and stirring was continued. The sulfur concentration in hexane was determined by x-ray fluorescence method.

All experiments were carried out sequentially on the same equipment using the same dishes. The conditions of the experiments in different experiments (mixing speed, immersion depth of the stirrer, temperature) were the same. When all samples were mixed, an emulsion was observed.

Table 3 shows the experimental results and shows the degree of purification of the hydrocarbon liquid by polysulfide compositions and sulfides.

The results shown in table 3 show that all tested polysulfide compositions (polysulfides of ethanolamines PS (A), polysulfides of ethanolamines treated with NaOH PS (B), and polysulfides of ethanolamines with the addition of Na ₂ S PS (C)) have the ability to purify hydrocarbon liquids from dissolved sulfur. Under experimental conditions, in all cases, complete removal of molecular sulfur occurred (experiments 2, 3, 4, 5, 6, 7). MEA solutions containing sodium and potassium sulfides with a concentration of from 0.05% wt. and more (experiments 8, 9, 10, 11) also have the ability to purify hydrocarbon liquid from molecular sulfur. However, unlike polysulfides, sodium and potassium sulfides are not inhibitors of steel corrosion in amine solutions. At elevated concentrations of ethanolamine and elevated temperatures, intense corrosion of steels is possible, moreover, corrosion products will remove sodium and potassium sulfides from the reaction sphere, forming insoluble iron sulfides.

Example 4

Sequential treatment of several samples of a hydrocarbon liquid containing dissolved sulfur with the same absorbent solution. After complete purification from sulfur, the organic phase was merged and a new portion of the solution to be purified was added.

Experimental conditions:

The cleaned hydrocarbon fluid is hexane containing 65 ppm sulfur. Cleaning solution (absorbent) - 30% wt. MEA solution containing 0.5% wt. polysulfide composition PS (B). The ratio of the phases "hydrocarbon: absorbent" is 3: 1. The temperature of the experiment is 40 ° C.

The experimental results are shown in table 4.

As follows from table 4, the MEA solution of 30% wt. concentration containing 0.5% wt. (5 g / l) of polysulfides can be repeatedly used without regeneration for purification of hydrocarbon liquid from molecular sulfur at a sulfur content of up to 65 ppm.

Example 5

To evaluate the sulfur intensity of an ethanolamine solution containing ethanolamine polysulfides, an experiment was performed on the purification of a hydrocarbon liquid containing a high concentration of dissolved molecular sulfur.

The conditions of the experiment:

The purified hydrocarbon liquid is hexane containing more than 0.1% wt. dissolved molecular sulfur. The cleaning solution is a 30% MEA solution containing 0.5% wt. (5 g / l) polysulfide composition PS (B). The ratio of the phases "hydrocarbon: absorbent" is 3: 1. The temperature of the experiment is 40 ° C.

The experimental results are shown in table 5.

As follows from table 5, the MEA solution of 30% wt. concentration containing 0.5% wt. (5 g / l) polysulfides can purify hydrocarbon liquids with a high molecular sulfur content, but this requires a longer contact time or an increase in ethanolamine concentration, polysulfide concentration, or an increase in the absorbent-hydrocarbon liquid ratio.

Example 6

The experiments were carried out on a bench installation including a reactor vessel and a centrifugal pump, which was used to create the movement of working media and as a vortex mechanism for their intensive mixing.

At the first stage of the experiment, hexane with molecular sulfur dissolved in it (~ 20 ... 40 ppm) was used as a model medium. As the absorbent was used 24% wt. MEA solution containing 1% wt. sodium sulfide and having a degree of saturation with carbon dioxide of 0.1 mol of CO ₂ / mol of MEA.

A series of test experiments was carried out at temperatures of 40 ... 47 ° C with a mixing time of 6 to 12 minutes. The hydrocarbon: absorbent phase ratio was 3.5: 1. As a result of the experiments, the molecular sulfur content in purified hexane was reduced to absence. Thus, this method allowed to achieve a deep degree of purification of a hydrocarbon liquid. Observations showed that in this case, an emulsion is formed "hydrocarbon liquid - absorbent", which quickly disintegrates.

At the second stage, using the same scheme as at the bench installation, experiments were carried out in which liquefied hydrocarbon gases were used as a cleaned hydrocarbon liquid. In this case, the installation was performed in metal to work with pressures corresponding to liquefied hydrocarbon gases at operating temperatures. The capacity of the reactor equipped with Clinker glass (for visual control of phase mixing) had a volume of 400 ml. To approach real conditions, in addition to molecular sulfur, hydrogen sulfide in an amount of up to 100 ppm was added to the hydrocarbon medium, and the absorbent was saturated with carbon dioxide. After the absorption cleaning, the liquefied hydrocarbon gas separated from the absorbent was washed with distilled water and treated (dried) with ethylene glycol. The degree and quality of purification of liquefied petroleum gas was additionally controlled by a copper plate in accordance with the methods of GOST 21443 and ASTM D-1838-03. By a similar technique, experiments were conducted on the purification of molecular sulfur BFLH obtained at one of the gas processing facilities. The experimental results are shown in table 6.

From the data shown in table 6, we can conclude that the use of the claimed method allows not only to efficiently purify liquefied petroleum gases, such as propane, propane-butane and BFLH (ESHLF), but also to ensure the quality of the purified product subject to the conditions stated in the method first class when tested on a copper plate.

Carrying out experiments on a bench installation, which provides efficient mixing and interaction of the hydrocarbon phase and the absorbent, significantly reduced the time required for purification of hydrocarbons, compared with experiments conducted in a flask with a stirrer.

Example 7

The cleaned hydrocarbon liquid is hexane containing 77 ppm molecular sulfur. The absorbent is an aqueous 24% MEA solution containing 0.2% wt. dissolved sodium sulfide and 0.5-10% (wt.) sodium hydroxide. The ratio of the phases "hydrocarbon: absorbent" is 3: 1. Cleaning temperature 40 ° C. Mixing time 5-30 minutes.

In order to more accurately determine the effect of adding sodium hydroxide to the absorbent solution on the degree of purification from molecular sulfur, the concentration of sodium sulfide was taken to be 0.2 wt%, which made it possible to increase the purification time in all experiments and reveal the resulting dependence.

Table 7 shows the effect of sodium hydroxide on the degree of purification from molecular sulfur.

As follows from table 7, the addition of ethanolamine containing sodium sulfide, sodium hydroxide to the solution has a significant effect on the purification of hexane from molecular sulfur at a content of sodium hydroxide in the absorbent in an amount of up to 5% wt.

Example 8

To determine the effect of phase transfer catalysts on the purification of hydrocarbon liquid from molecular sulfur, experiments were carried out to introduce triethylbenzylammonium chloride (TEBAC) into the absorbent solution.

Experimental conditions:

The cleaned hydrocarbon liquid is hexane containing 77 ppm molecular sulfur. Absorbent - water 24% wt. MEA solution containing 0.2% wt. dissolved sodium sulfide and 0.01-2% wt. TEBAH. The ratio of the phases "hydrocarbon: absorbent" is 3: 1. Cleaning temperature 40 ° C.

Table 8 shows the experimental results.

According to the results presented in table 8, we can conclude that the addition of a phase transfer catalyst to the absorbent solution affects the purification of hydrocarbon liquid from molecular sulfur in an amount of up to 1% wt.

Claims (4)

1. The method of purification of liquefied hydrocarbon gases from molecular sulfur, sulfur compounds and carbon dioxide, comprising mixing a hydrocarbon liquid with an absorbent containing sulfides and / or polysulfides, with the formation after mixing of a two-phase layer consisting of an aqueous layer of absorbent containing extracted from the purified hydrocarbon liquid specified components, and a layer of purified hydrocarbon liquid with a reduced content of these components, characterized in that as an absorbent using an aqueous solution of ethanolamine with a concentration of 18-72 wt.% containing water-soluble sulfides and / or polysulfides selected from the series: sulfides and / or polysulfides of alkali, alkaline earth metals, ammonium, and ethanolamines, while the concentration of sulfides and / or polysulfides in an aqueous solution of ethanolamine is not less than 0.05 wt.%, the mixture of the hydrocarbon liquid with the absorbent is carried out in an amount necessary for the formation, after completion of mixing, of the aqueous layer of the absorbent containing extracted from the purified carbohydrate foreign liquid, molecular sulfur, sulfur compounds and carbon dioxide, and a layer of hydrocarbon liquid with no or reduced content of molecular sulfur, sulfur compounds and carbon dioxide, which is then decanted from the aqueous absorbent layer to obtain a purified product. 2. The method according to p. 1, characterized in that the ethanolamines in the aqueous solution are selected from the series: monoethanolamine, diethanolamine, methyldiethanolamine. 3. The method according to p. 1, characterized in that the composition of the absorbent injected alkali metal hydroxides in an amount of not more than 5 wt.%. 4. The method according to p. 1, characterized in that the phase-transfer catalysts are introduced into the absorbent, such as: quaternary ammonium salts, phosphonium salts, in an amount of not more than 1 wt.%.