Method for processing mercaptan-containing hydrocarbon gas

Abstract

The invention relates to a method for processing mercaptan-containing hydrocarbon gas. The method includes the following procedures: (a) amine purification of hydrocarbon gas, and regeneration of the saturated amine solution, (b) adsorption drying of the purified hydrocarbon gas, (c) regeneration of the saturated adsorbent, and cooling of the adsorbent, (d) compression and cooling of the spent regeneration gas, which is sent for mixing with hydrocarbon feedstock gas, (e) sulphur recovery. The amine purification procedure (a) uses an amine solution that prevents the extraction of mercaptans from the hydrocarbon gas. The hydrocarbon gas adsorption drying procedure (b) is combined with a procedure for further adsorption purification of the hydrocarbon gas to remove mercaptans (f). The spent regeneration gas from procedure (c) is cooled and sent to a further procedure of alkali purification to remove mercaptans (g), in which the mercaptans are converted into mercaptides. The mercaptide-saturated alkaline extractant is sent for regeneration, wherein the mercaptides contained in the extractant are converted into disulphides, which are discharged from the apparatus in the form of disulphide oil, and the purified regeneration gas is sent to procedure (d). The invention makes it possible to reduce emissions of sulphur-containing impurities into the atmosphere.

Description

[0001] METHOD FOR PROCESSING HYDROCARBON GAS CONTAINING MERCAPTANS

[0002] FIELD OF TECHNOLOGY

[0003] The method for processing hydrocarbon gas containing mercaptans is intended to prepare hydrocarbon gas for further transportation or processing, including into valuable gas chemical products, and can be used at enterprises in the gas, oil, oil refining and petrochemical industries.

[0004] Removing acidic components from hydrocarbon gases, such as carbon dioxide, hydrogen sulfide, and sulfur-containing compounds such as mercaptans (the most common being methyl mercaptan and ethyl mercaptan), is a mandatory procedure before feeding them into main pipelines to prevent pipe corrosion. The acid gas content of natural gas from different fields or in associated gases typically varies greatly. The total amount of mercaptans in a gas mixture can reach several hundred ppm by volume. The acceptable acid gas content in the purified gas is specific to each feedstock type and the planned processing method for the purified gas. Currently, numerous methods exist for the sequential or simultaneous removal of acid gases and other sulfur-containing compounds from gas mixtures. Given the specific properties of each product being removed, these processes typically involve several different sequential steps.In a standard purification option, carbon dioxide and hydrogen sulfide are removed in an amine purification step using monoethanolamine or diethanolamine, and other sulfur-containing compounds, such as mercaptans or COS, are removed using special processes such as adsorption on a molecular sieve or washing with soda (patent for invention US20150139877, IPC BOID 53 / 14, BOID 53 / 52, C10L 3 / 10, C10L 3 / 12, declared on 23.05.2013, published on 21.05.2015).

[0005] A method is known for purifying a natural gas stream, which comprises: feeding a natural gas stream containing mercaptans to an amine-based separation unit; contacting the natural gas stream containing mercaptans with an amine-containing absorption liquid in the amine-based separation unit and separating the natural gas stream containing mercaptans into a first natural gas stream enriched in mercaptans and a second stream; feeding at least a portion of a first natural gas stream enriched in mercaptans to a selective catalytic oxidation unit and converting at least a portion of the mercaptans in the first natural gas stream enriched in mercaptans into elemental sulfur in the selective catalytic oxidation unit - by selective catalytic oxidation, obtaining a purified natural gas stream depleted in mercaptans (patent for invention US201 10265380, IPC BOID 53 / 14, C10L 3 / 10, BOID 53 / 86, filed on 26.11.2009, published on 03.11.2011).The disadvantages of the invention are:

[0006] • as a rule, catalytic gas purification processes require heating of the entire flow of gas being purified;

[0007] • high requirements for the quality of the purified gas in terms of the content of catalytic poisons (for example, mercury, heavy metals and others);

[0008] • formation of oxidation by-products.

[0009] Also known is a method for purifying a gas for processing a gas stream, which includes: feeding a gas stream into at least one membrane unit to obtain a permeate stream and a retentate stream, wherein the retentate stream contains a lower concentration of at least one of the components: water, hydrogen sulfide or carbon dioxide compared to the gas stream; and feeding the retentate stream into a molecular sieve unit to remove hydrogen sulfide to obtain a purified gas product stream; wherein the change in pressure between the gas stream and the permeate stream is from about 300 pounds per square inch to about 1500 pounds per square inch (patent for invention US20130298765, IPC BOID 59 / 12, filed on 09 / 05 / 2012, published on 11 / 14 / 2013).

[0010] The disadvantages of the invention are:

[0011] - this invention solves the problem of purifying natural gas, but does not solve the problem of utilizing sulfur-containing components of natural gas;

[0012] - low permeate pressure, in which the removed impurities are concentrated;

[0013] - lack of clear separation on the membranes, due to which there are large losses of hydrocarbons with the permeate flow.

[0014] A method for purifying a gas mixture containing acid gases is known, which includes the step of contacting said gas mixture with an absorbing solution, characterized in that the absorbing solution contains an alkanolamine, a C2-C4 thioalkanol and water (Patent of the Republic of Kazakhstan No. 24294, class BOID 53 / 14, C07C 7 / 11, published on 15.07.2011, Bulletin 7). The disadvantages of the invention are:

[0015] - according to the formula of the invention, the said absorbent solution reduces the concentration of mercaptans contained in the gas mixture to a value below approximately 5 ppm, however, the claimed depth of purification has not been proven, since in example 1 there is no information on the depth of purification, and in Fig. 1 the concentration of mercaptan at the outlet of the absorber is in the range of 50-100 ppm;

[0016] - there is no data on the possibility of regenerating the solvent with the release of absorbed acid gases from it and their subsequent use or disposal.

[0017] A method is known for deep drying and purification of natural or associated petroleum gas from sulfur compounds, followed by purification of regeneration gas from hydrogen sulfide and subsequent utilization of regeneration gas, including adsorption of water vapor and sulfur compounds, regeneration of the adsorbent at an elevated temperature by a reverse flow of purified gas, cooling the adsorbent to the adsorption temperature and subsequent purification of the regeneration gas, wherein the natural gas is preliminarily separated from the liquid droplet, a solid layer of highly effective zeolite CaA is used as the adsorbent, the regeneration of the zeolite is carried out at reduced pressure and an elevated temperature of at least 290 °C by a reverse flow of dried and purified gas, after each interaction with the adsorbent, the gas being purified is filtered from adsorbent dust particles, and the regeneration gas is purified on a non-regenerable adsorbent containing zinc oxide ZnO,at a temperature of 300 °C or with an amine solution of DEA in an absorber (patent for invention RU 2805060, IPC BOID 53 / 26, BOID 53 / 04, COIB 17 / 16, C10L 3 / 00, filed on 27.12.2022, published on 11.10.2023). The disadvantages of the invention are:

[0018] - according to the given example, the acid gas formed during the process of amine cleaning of regeneration gas is sent to the flare, which in turn negatively affects the environmental friendliness of the claimed method;

[0019] - this invention does not solve the problem of purifying natural or associated petroleum gas from mercaptans, since during the regeneration of the adsorbent from sulfur-containing compounds, the aqueous solution of DEA does not absorb mercaptans during the subsequent purification of the exhaust gas from regeneration;

[0020] - high energy consumption of the method, since the adsorbent regeneration gas with a temperature of about 300 °C (the permissible temperature for zeolite regeneration is 300-350 °C) must be heated to 360-550 °C to carry out the reaction of hydrogen sulfide with zinc oxide (at 300 °C, this reaction is practically not realized).

[0021] The closest to the claimed invention is a method for processing natural gas with an increased content of acidic components, sequentially including the following stages: a) separation and metering of the consumption of raw natural gas, b) absorption purification of the separated natural gas from acidic components and mercaptans with regeneration of the absorbent and obtaining sulfur-containing acid gases, c) drying of the purified natural gas, d) obtaining elemental sulfur by the Claus method from sulfur-containing acid gases, d) granulation and storage of commercial sulfur, e) metering of commercial natural gas sent to consumers, g) thermal disposal of waste, h) obtaining propane cold, while in the case of the content of acidic components in the raw natural gas of at least 19 mol.and a carbon dioxide:hydrogen sulfide ratio greater than 1.7, stage (b) is carried out sequentially in two stages: in the first stage, hydrogen sulfide is selectively extracted from the separated natural gas, and in the second stage, carbon dioxide and mercaptans, stage (c) is implemented by absorption drying or low-temperature separation of natural gas using stage (h), and stage (g) additionally receives acid gases stripped from the condensate containing dissolved hydrogen sulfide isolated in stage (a), expansion gases of the first and second stages of stage (b), acid desorption gases formed during the regeneration of the absorbent in the second stage of stage (b), as well as weathering gases and condensate formed in stage (c), wherein water vapor formed in the waste heat boilers in stage (d) and the exhaust gas afterburner in stage (g) is used as a heat carrier for regeneration absorbents at stages (b) and (c) (patent for invention RU 2705352, IPC BOID 53 / 00, filed 26.06.2019, published 06.11.2019).

[0022] The disadvantages of the invention are:

[0023] - low conversion of hydrogen sulfide into elemental sulfur (at the level of 80%) in the case of acid gas entering the Claus process from the selective amine purification process (the first stage of purification) with an extremely low content of hydrogen sulfide (from 2 to 10% mole), due to the impossibility of ensuring an acceptable concentration of hydrogen sulfide in the acid gas in the selective amine purification process when processing raw gas with a significantly low H2S / CO2 ratio;

[0024] - low conversion of hydrogen sulfide to elemental sulfur in the Claus process with reduced acid gas flow rates (less than 60% of the nominal value), which in turn limits the applicability of this process to feed gas with a wide flow rate range, which is typical for centralized associated petroleum gas processing facilities at various fields. For such applications, the chemical conversion of hydrogen sulfide to sulfur (liquid-phase oxidation with a chelate solution) is typically used. However, this method, unlike the Claus process, does not convert mercaptans to sulfur;

[0025] - the use of a second stage of absorption purification, in which carbon dioxide and mercaptans are extracted, significantly increases the energy costs of the process, since a significant increase in the consumption of a hybrid absorbent containing a polar component that absorbs mercaptans is required to maintain the required degree of saturation of the absorbent from 0.05 to 0.2 mol of carbon dioxide per mol of amine, which is up to 4 times lower than the permissible standard for amine purification without the extraction of mercaptans;

[0026] - the acid gas from the second stage of absorption purification, containing mercaptans, is sent for thermal disposal, which in turn negatively affects the environmental friendliness of the claimed method;

[0027] - the absorption gas drying method does not meet the requirements for deep gas drying for subsequent cryogenic processing;

[0028] - the method of gas drying by low-temperature separation of natural gas using propane cold requires the use of a hydrate formation inhibitor (methanol or ethylene glycol) and subsequent purification of condensed hydrocarbons from the inhibitor.

[0029] When mercaptans are introduced into a Claus sulfur recovery unit with the acid gas stream from the amine treatment unit, the conversion of hydrogen sulfide to sulfur may be reduced. When using liquid-phase oxidation (e.g., iron chelates) to extract sulfur from the acid gas stream, mercaptans are virtually not recovered and are sent to the thermal oxidizer for combustion with the tail gas stream, thereby increasing sulfur compound emissions into the atmosphere.

[0030] DISCLOSURE OF THE INVENTION

[0031] The objective of the claimed invention is to develop an environmentally friendly method for purifying hydrocarbon gases from acidic components and drying them, ensuring the removal of mercaptans from hydrocarbon gases and obtaining commercial products based on them.

[0032] The technical result of the present invention is:

[0033] - reduction of emissions of sulfur-containing impurities into the atmosphere; simplification of the technological scheme of the hydrocarbon gas processing process;

[0034] - reduction in the number of technological equipment; production of additional commercial products based on extracted mercaptans.

[0035] The problem set is solved due to the fact that in the method for processing hydrocarbon gas containing mercaptans, including the procedures of: a) amine purification of hydrocarbon gas from carbon dioxide and hydrogen sulfide in an absorber with a flow of an aqueous amine solution to obtain purified hydrocarbon gas and regeneration of a saturated amine solution in an amine regeneration column, in which acid gases are stripped; b) adsorption drying of the purified hydrocarbon gas to obtain a prepared hydrocarbon gas; c) regeneration of the saturated adsorbent with a flow of hot regeneration gas and cooling of the adsorbent with a flow of cooling gas; d) compression and cooling of the exhaust regeneration gas with feeding for mixing with the raw hydrocarbon gas;d) obtaining sulfur by a chemical method from an acid gas stream, in the amine purification procedure (a) an amine solution is used that excludes the extraction of mercaptans from the hydrocarbon gas, and the procedure of adsorption drying of hydrocarbon gas (b) is combined with the procedure of additional adsorption purification of hydrocarbon gas from mercaptans (e), and the waste gas from the regeneration procedure (c) is cooled and sent to an additional procedure of alkaline purification from mercaptans (g), wherein mercaptans are converted into mercaptides, and the alkaline extractant saturated with mercaptides is fed to regeneration with the conversion of the mercaptides contained in it to disulfides, which are removed from the plant in the form of disulfide oil, and the purified regeneration gas is fed to procedure (d).;

[0036] Regeneration gases from the adsorption drying and purification process of hydrocarbon gas at temperatures of 280-350°C contain desorbed water and mercaptans. When the regeneration gases are cooled, partial condensation of water occurs, separated from the cooled hydrocarbon gas and sent to the amine purification unit to replenish the aqueous amine solution. The cooled hydrocarbon gas then contacts an aqueous alkali solution, such as sodium hydroxide. During the extraction process, mercaptans are converted to sodium mercaptides via reactions (1) and (2):

[0037] - methyl mercaptan is converted into sodium methyl mercaptide:

[0038] CH3SH + NaOH — ► CH3SNa + H2O, (1)

[0039] - ethyl mercaptan - to sodium ethyl mercaptide:

[0040] CH3CH2SH + NaOH — ► CH3CH2SNa + H2O, (2) in this case, methyl mercaptan is extracted from the regeneration gas almost completely, and ethyl mercaptan – by 97.1%.

[0041] When purging the reaction medium with air (it is possible to intensify the process using catalysts) during the regeneration of the spent alkaline solution, mercaptides form disulfides: dimethyl sulfide, methyl ethyl sulfide, diethyl sulfide according to the scheme (3): 2RSNa + 0.502 + H2O -► RSSR + 2NaOH, (3) with the formation of intermediate hydrogen peroxide.

[0042] The resulting disulfides, due to their poor solubility in aqueous systems, are easily separated from the reaction mixture by settling and other methods of separating heterogeneous systems and are then widely used, for example, to increase the oxidative stability of motor fuels, to dissolve asphaltene-resin-paraffin deposits in process equipment, pipelines and for other purposes.

[0043] It is possible to use associated petroleum gas, natural gas, or a mixture of both as the raw hydrocarbon gas, which expands the raw material base of the method.

[0044] It is advisable to combine the adsorption drying of hydrocarbon gas with the mercaptan removal process. The adsorption cycle utilizes a system of at least three adsorbers operating in a cyclical pattern, with each adsorber sequentially performing an adsorption stage, an adsorbent regeneration stage, and an adsorbent cooling stage. This combination simplifies the natural gas processing flow chart and its maintenance, and reduces the number of process units, thereby lowering the cost of the process.

[0045] It is rational to carry out the adsorption of moisture and mercaptans from hydrocarbon gas using selective adsorption methods on zeolites to increase the efficiency of gas purification and drying, due to the fact that synthetic zeolites provide the highest degree of gas drying and stability during long-term operation, and the use of zeolites of various forms allows the selection of adsorbents that absorb a specific type of impurity, the molecules of which are able to penetrate into the cavities of the zeolites through the windows of its structure.

[0046] For the adsorption of moisture from hydrocarbon gases, it is advisable to use A-type zeolites (type A), in which the SiO2:Al2O3 ratio is no higher than 2. Type A zeolite absorbs industrial gas components with a critical molecular size of no more than 0.4 nm, i.e., it practically does not sorb organic compounds with more than 3 carbon atoms. Since higher hydrocarbons do not penetrate the fine pore structure of NaA zeolites, deactivation is eliminated and the service life of the zeolite is significantly increased. NaA zeolite operates reliably with changes in initial humidity and gas flow rate, which is important for ensuring the required gas dehydration depth in industrial conditions.

[0047] It is advisable to use X-type zeolites for the adsorption of mercaptans from hydrocarbon gas. Type X zeolites have larger inlet windows than type A zeolites and adsorb most high-molecular-weight hydrocarbons: all types of hydrocarbons, organic sulfur compounds, mercaptans, and halogenated hydrocarbons. Type X zeolites also exhibit increased adsorption activity for organosulfur impurities compared to hydrocarbons. Furthermore, the NaX adsorbent requires a higher regeneration temperature, which ensures deeper desorption of mercaptans.

[0048] Due to the differences in the adsorption capacity of A-form and X-form zeolites with respect to moisture and mercaptans, A-form and X-form zeolites can be placed in separate apparatus.

[0049] It is advisable to place A-form and X-form zeolites in separate layers in one apparatus sequentially in the direction of gas flow at the adsorption stage, taking into account the composition of the gas supplied for adsorption according to the content of the absorbed components, which simplifies the process flow diagram and reduces the number of apparatuses in the installation.

[0050] Before procedure (g), cool the regeneration exhaust gas to a temperature of at least 70°C, separating the water condensate. This prevents methyl and ethyl mercaptan from condensing and contaminating the water condensate. The water condensate formed during regeneration gas cooling is sent to procedure (a) to reduce the amount of fresh makeup water.

[0051] It is advisable to return the flow of purified regeneration gas to procedure (b) to reduce the feedstock load of procedure (a).

[0052] It is possible that the hydrogen sulfide content in the hydrocarbon gas supplied for processing ranges from 0.03 to 0.3% by mole, the carbon dioxide content from 0.5 to 5% by mole, and the mercaptan content from 50 to 1000 ppmv.

[0053] It is advisable to use part of the stream of prepared hydrocarbon gas, or the methane fraction, or the methane-ethane fraction, or the stripped gas, separated from the prepared gas during subsequent processing, as the regeneration gas and cooling gas for procedure (c).

[0054] LIST OF DRAWINGS

[0055] Figure 1 shows a basic diagram of the implementation of one of the possible variants of the method for processing hydrocarbon gas containing mercaptans, using the following designations:

[0056] 1-13 - pipelines;

[0057] 100 - amine gas purification unit;

[0058] 200 - drying and mercaptan removal unit;

[0059] 300 - alkaline gas regeneration cleaning unit;

[0060] 400 - alkali solution regeneration unit;

[0061] 500 - regeneration gas compression unit;

[0062] 600 - sulfur production unit.

[0063] BRIEF DESCRIPTION OF DRAWINGS

[0064] The method for processing hydrocarbon gas containing mercaptans involves feeding the hydrocarbon gas via pipeline 1 to amine gas purification unit 100, which is carried out in an absorber where hydrogen sulfide and carbon dioxide are extracted from the gas using an aqueous solution of diethanolamine (DEA) at a feed gas pressure of 6 MPa (e) and a temperature of 45 °C. The gas, purified from acidic components, is fed via pipeline 2 to drying and mercaptan purification unit 200, which involves the adsorption of moisture and mercaptans by zeolites in fixed-bed adsorbers. The number of adsorbers and their operating cycle ensure the operation of at least one adsorber in the gas drying and mercaptan purification mode, and at least one adsorber in the regeneration and cooling mode. The number of adsorbers in the gas drying and purification, regeneration and cooling modes may vary.The duration of each stage of the cyclogram can be the same and be, for example, 8 hours, which is convenient for organizing stable process control. A portion of the dried and purified gas is used as cooling gas and regeneration gas for the adsorbers, while the main portion of the dried and purified gas is discharged as treated gas through pipeline 3. The regeneration exhaust gas after the adsorber is cleaned of zeolite dust, cooled to 70°C, passes through a separator to separate condensed moisture, which is removed as a condensate stream through pipeline 4, and is fed through pipeline 5 to the alkaline gas purification unit 300. Alkaline extraction is used to remove mercaptans and residual hydrogen sulfide from the regeneration gas through chemisorption, forming hydrocarbon-insoluble mercaptides and sodium sulfide.The resulting mercaptide-saturated alkaline solution is fed via pipeline 6 to alkaline solution regeneration unit 400, where, as a result of oxidation with atmospheric oxygen in the presence of a heterogeneous or homogeneous liquid-phase catalyst, the mercaptides are converted into disulfides, separated from the regenerated alkaline solution and removed from the system in the form of disulfide oil via pipeline 7, and the regenerated alkaline solution is returned via pipeline 8 to alkaline gas purification unit 300 for regeneration. Purified regeneration gas from alkaline gas purification unit 300 is sent via pipeline 9 to regeneration gas compression unit 500, from where it is fed via pipeline 10 to drying and mercaptan removal unit 200.The saturated amine solution obtained in the absorber of the amine gas purification unit 100 enters the amine regeneration column, in which the acid gases are stripped and then fed through pipeline 11 to the sulfur production unit 600, designed to obtain elemental sulfur by a chemical method, which is removed from the unit through pipeline 12, and the tail gas is sent through pipeline 13 for combustion in a thermal oxidizer.

[0065] Example. A calculation was performed for the processing of hydrocarbon gas containing mercaptans, with a capacity of 158.6 tons / hour of feedstock according to the claimed invention, with the possibility of subsequent delivery of the treated gas to a main gas pipeline or to a low-temperature hydrocarbon component extraction plant (Sz). И higher-

[0066] Coming:

[0067] Natural hydrocarbon gas - 158.6 t / h, including:

[0068] Name kg / h

[0069] Methane 86800.0

[0070] Ethane 26600.0

[0071] Propane 22400.0

[0072] Isobutane 5600.0 N-butane 8400.0 Nitrogen 5600.0 Hydrogen sulfide 350.0

[0073] Carbon dioxide 2800.0 Methyl mercaptan 9.8 Ethyl mercaptan 4.2 Propyl mercaptan 1.4 Water 70

[0074] Consumption:

[0075] 1) Commercial fuel hydrocarbon gas - 155.33 t / h, including: Methane 86758 kg / h Ethane 26586 kg / h Propane 22391 kg / h Isobutane 5598 kg / h N-butane 8398 kg / h Nitrogen 5599 kg / h Hydrogen sulfide no more than 1 ppmv Carbon dioxide no more than 1 ppmv Mercaptans no more than 5 mg / st.m 3 Water (dew point) no more than minus 75 °C

[0076] 2) Commercial sulfur - up to 0.3 t / h

[0077] 3) Commercial disulfide oil - up to 15 kg / h.

[0078] Thus, the claimed invention solves the problem of developing an environmentally friendly method for processing hydrocarbon gas containing mercaptans, ensuring the removal of mercaptans from hydrocarbon gases with the production of a commercial product based on them in the form of disulfide oil and achieving the following technical result:

[0079] - reduction of emissions of sulfur-containing impurities into the atmosphere;

[0080] - simplification of the technological scheme of the natural gas processing process;

[0081] - reduction in the number of technological devices;

[0082] - production of additional commercial products of disulfide oil based on extracted mercaptans.

Claims

CLAUSES OF THE INVENTION 1. A method for processing hydrocarbon gas containing mercaptans, comprising the procedures of: a) amine purification of hydrocarbon gas from carbon dioxide and hydrogen sulfide in an absorber with a stream of an aqueous amine solution to obtain purified hydrocarbon gas and regeneration of the saturated amine solution in an amine regeneration column in which acid gases are stripped; b) adsorption drying of the purified hydrocarbon gas to obtain prepared hydrocarbon gas; c) regeneration of the saturated adsorbent with a stream of hot regeneration gas and cooling of the adsorbent with a stream of cooling gas; d) compression and cooling of the exhaust regeneration gas with its supply for mixing with the raw hydrocarbon gas;d) obtaining sulfur by a chemical method from an acid gas stream, characterized in that in the amine purification procedure (a) an amine solution is used that excludes the extraction of mercaptans from the hydrocarbon gas, and the procedure of adsorption drying of hydrocarbon gas (b) is combined with the procedure of additional adsorption purification of hydrocarbon gas from mercaptans (e), and the waste gas from the regeneration procedure (c) is cooled and sent to an additional procedure of alkaline purification from mercaptans (g), wherein mercaptans are converted into mercaptides, and the alkaline extractant saturated with mercaptides is fed to regeneration with the conversion of the mercaptans contained therein to disulfides, which are removed from the plant in the form of disulfide oil, and the purified regeneration gas is fed to procedure (d).; 2. The method according to paragraph 1, characterized in that associated petroleum gas, or natural gas, or a mixture of both is used as the raw hydrocarbon gas.

3. The method according to paragraph 1, characterized in that the procedure of adsorption drying of hydrocarbon gas, combined with the procedure of purifying hydrocarbon gas from mercaptans, is implemented in a system of adsorbers operating according to a cyclogram, wherein in each adsorber an adsorption stage, an adsorbent regeneration stage, and an adsorbent cooling stage are sequentially carried out.

4. The method according to paragraph 3, characterized in that the adsorption of moisture and mercaptans from the hydrocarbon gas is ensured by selective adsorption.

5. The method according to paragraph 3, characterized in that the adsorption of moisture from the hydrocarbon gas is provided by A-form zeolites and the adsorption of mercaptans from the hydrocarbon gas is provided by X-form zeolites.

6. The method according to paragraph 5, characterized in that the A-form and X-form zeolites are placed in separate apparatuses.

7. The method according to paragraph 5, characterized in that the A-form and X-form zeolites are placed in separate layers in one apparatus sequentially in the direction of gas flow at the adsorption stage.

8. The method according to paragraph 1, characterized in that the flow of purified regeneration gas is returned to procedure (b).

9. The method according to claim 1, characterized in that the content of hydrogen sulfide in the raw hydrocarbon gas supplied for processing fluctuates in the range from 0.03 to 0.3 mole%, the content of carbon dioxide from 0.5 to 5 mole%, and the content of mercaptans from 50 to 1000 ppmv.

10. The method according to paragraph 1, characterized in that the regeneration gas and the cooling gas of procedure (c) are part of the stream of prepared hydrocarbon gas or a methane fraction, or a methane-ethane fraction, or stripped gas, separated from the prepared gas during subsequent processing.

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