MXPA98005795A - Method for removing contaminants containing sulfur, aromatic compounds and hydrocarbons apparatus of a - Google Patents

Abstract

The invention relates to a method for removing contaminants containing sulfur in the form of mercaptans and H2S from a hydrocarbon gas, which can also contain CO2 and higher aliphatic and aromatic hydrocarbons, and recover elemental sulfur, where in a first step of absorption the sulfur-containing pollutants are removed from the gas, to form on the one hand a stream of purified gas and on the other hand a gas with a high content of mercaptans, a gas with a high content of mercaptans which is hydrogenated to convert most of the mercaptans to H2S, where subsequently the gas with high content of mercaptans, hydrogenated, is fed to a second stage of absorption in which the gas with high content of mercaptans is separated in a first gas stream enriched with H2S, which is it feeds a Claus plant, followed by a step of selective oxidation of H2S to elemental sulfur in the tail gas, and a second stream of gas with less amount of H2S, second gas stream which is

Description

METHOD FOR REMOVING CONTAMINANTS CONTAINING SULFUR, COMPOUNDS AROM TICOS AND HYDROCARBONS ñ STARTING FROM A GAS DESCRIPTION OF THE INVENTION This invention relates to a method for purifying gas, more particularly hydrocarbon gas, such as natural gas, which is contaminated with sulfur compounds in the form of H 2 S and mercaptans, as well as with C02. More particularly, the invention comprises a method for converting mercaptans to H2S in, and removing C02, hydrocarbons and aromatics absorbed from the gas containing H2S to form elemental sulfur from H2S. In the purification of natural gas, purification of refinery gases and the purification of synthesis gas, ¿5 *} Sulfur-containing gases, in particular H2S, are released, which can be removed to limit the emission to the atmosphere, particularly of SO2, which is formed after the combustion of such sulfur compounds. The degree in which the sulfur compounds are removed from, for example, natural gas, depends on the intended use of the gas and the set of quality requirements. When the gas must meet the so-called "pipeline specifications" the H2S content should be reduced to a value below 5 mg / Nn3. The requirements are also met with respect REF: 27870 to the maximum content of other sulfur compounds. Of the A large number of methods are known by prior art by which the amount of sulfur compounds in a gas, such as natural gas, can be reduced. For the removal of sulfur-containing components from gases, the following process route is usually employed. In a first step the gas to be treated is purified, so the sulfur-containing components are removed from the gas, followed by recovery of sulfur from In the case of two sulfur-containing components, a sulfur purification step of the waste gas is subsequently ensured. In this step of sulfur purification, it is intended to recover the last percentages of sulfur before the residual gas is emitted via the pile or pavilion towards the atmosphere. In the purification step, procedures are used in which aqueous solvents (absorption agents) are often used. These procedures are divided into five main groups, viz. The procedures with chemical solvent, physical solvent procedures, physical / chemical solvent procedures, redox procedures, by means of which H2S is oxidized directly to sulfur in an aqueous solution and finally a group of fixed-bed processes by means of which the HS is 2 £ > adsorbed or absorbed chemically or physically or is catalytically oxidized selectively to elemental sulfur. The first three groups mentioned are commonly used in the industry for the removal of large quantities of sulfur-containing components, most often present in large quantities of gas. The last two groups are limited with respect to the amount of sulfur to be removed and the concentration of the sulfur-containing components. These procedures are therefore less suitable for the removal of high sulfur concentrations in large industrial gas purification plants. The chemical solvent process includes the so-called amine process, in which use is made of aqueous solutions of alkanolamines or potassium carbonate solutions. =. In the physical solvent process, different chemical products are used. For example, polyethylene glycol (DMPEG) known under the name of Selexol, N-Methyl-Pyrrolidone (NMP), known under the name of 0 Purisol, or methanol, known under the name of Rectisol. In the group of physical / chemical procedures, the procedure with Sulfinol is well known. In this process, use is made of a mixture of an alkanolamine with sulfolane dissolved in a small amount of water.

In the three methods mentioned above, an absorption device and a regenerator are used. In the absorption device, the sulfur-containing components are chemically or physically bound to the solvent. By reducing the pressure and / or increasing the temperature in the regenerator, the sulfur-containing components are desorbed from the solvent, subsequently the solvent can be reused. A detailed description of this method is found in R. N. Medox "Gas and Liquid S eetening" 10 Ca pbelll Petroleum Series (1977). In this method, in addition to the sulfur-containing components, C02 is also partially or completely removed, depending on the solvent chosen. The sulfur compounds removed together with the C02 are routed from the regenerator to a X l Sulfur recovery to recover sulfur from H2S and other sulfur compounds. A procedure frequently used to recover the sulfur from the sulfur compounds thus obtained, in particular H2S, is the Claus method. This procedure is described in detail in H. G. Paskall, "Capability of the modified Claus process", Western Research Development, Calgary, Alberta, Canada, 1979. The Claus procedure consists of a thermal step typically followed by two or three reactor steps.

MM- In the thermal passage one third of the H2S is burned to S02 in accordance • * - '2 > . to the reaction.

H2S + 1.5 02? S02 + H20 5 later the rest, that is, 2/3 of the H2S reacts with the S02 formed, according to the reaction of Claus, to form sulfur and water. 0 2 H2S + S02? 3 S + 2 H20 The efficiency of the Claus procedure depends on numerous factors. For example, the equilibrium of the Claus reaction deviates in the direction of the H2S with an increase on the water content in the gas. The efficiency of the sulfur recovery plant can be increased by the use of a tail gas sulfur recovery plant; the known methods are the SUPERCLAUS ™ procedure and the SCOT procedure. In the SUPERCLAUS "0 process, a catalyst is used as described in the European patent applications 242,920 and 409,353, as well as in the international patent application WO-A 95,07856, where this catalyst is used in a third or fourth stage of reactor as described inter alia in "Hydrocarbon fflt Processing" of April 1989, pp. 40-42. Using this method, the last H2S residues present in the process gas stream are selectively oxidized to elemental sulfur according to the reaction H2S + 0.5 02 - - S + H20 In this way the efficiency of the unit sulfur recovery can easily rise to the 99. 5%. The gas fed to the Claus plant can sometimes contain large amounts of C02 for example up to 98. 5%, which has a highly adverse effect on the temperature of the flame in the thermal passage. A great quantity of C02 can lead to instability of the flame and also : 7 faith the efficiency in the thermal step will decrease, so that the total efficiency of the Claus plant decreases. Also, the gas may contain large amounts of hydrocarbons. When the sulfur-containing gas is When processed in an oil refinery gas, the hydrocarbon content will generally be lower, mostly of < 2% in volume. In the purification of natural gas where physical or physical / chemical procedures are used, such as result of the absorption of large quantities of Hydrocarbons and aromatics, respectively, can finally increase in the gas that is passed to the sulfur recovery plant (Claus gas). In the thermal stage of the Claus plant, these hydrocarbons are completely burned because the reaction rate of the hydrocarbons with oxygen is greater than the reaction rate of H2S and oxygen. When large amounts of C02 are present, the temperature of the flame will consequently decrease, and consequently also the reaction speed of the components during combustion. As a result, soot formation may occur in the flame of the thermal stage burner. The formation of soot gives rise to blockage problems in the catalytic reactors of a Claus plant, in particular the first reactor. Also, the relationship between the oxygen requirement for the conversion of H2S to sulfur and the oxygen requirement for the combustion of hydrocarbons and aromatics can take such values that the Claus process can no longer be controlled properly. These problems are known in the industry. In addition, in addition to H2S and the large amounts of C02 mentioned above, mercaptans are also frequently present in the gas. In industry, chemical procedures are used in which mercaptans are not removed from the gas to be purified, S ^^ 'example, natural gas, so that a subsequent cleaning procedure with a fixed bed is not necessary. Molecular sieves are often used for the removal of these mercaptans. However, when such a fixed bed is saturated with mercaptans, the molecular sieves must be regenerated, for which purpose purified natural gas is often used. This gas regeneration could then be 0 purified at the same time. In the regeneration of molecular sieves, mercaptans are released for the most part at the beginning of regeneration. There are also procedures in which the mercaptans of a subsequent purification stage are returned to the Claus plant. Those mercaptans then give a peak load in the thermal stage of the Claus plant, so that air control is severely disturbed. Such a procedure route is described in Oil and Gas Journal 57, August 19, 1991, pp. 57 - 59. In addition, this leads to a loss of natural gas, which 0 can easily rise to about 10%. The method for the processing of sulfur-containing gases, which contain carbonyl sulphide and / or other organic components such as mercaptans and / or dialkyl disulfides, is well known. This method is described in British Patent No. 1563251 and in the ^ British Patent Number 1470950. An object of the present invention is inter alia to provide a method for the removal of sulfur-containing contaminants in the form of mercaptans and H2S from a hydrocarbon gas, such as natural gas, which may also contain C02. and higher aliphatic and aromatic hydrocarbons, and the recovery of elemental sulfur, method in - which the disadvantage exposed above does not occur. From More particularly, an object of the invention is to provide a method by which the tail gases containing not only a few dangerous substances, so that they can be discharged into the atmosphere without any objection. It is also an object of the invention to provide a method by which sulfur-containing contaminants are recovered at a high grade as elemental sulfur, for example up to an amount of more than 90%, more particularly greater than 95%. The present invention provides a simple method to purify hydrocarbon gas contaminated with the recovery of sulfur, according to which the method in a first step of absorption of the sulfur-containing contaminants are removed from the gas, to form on the one hand a stream of purified gas and on the other side a gas with high content of mercaptans, gas with high content of mercaptans which is hydrogenated to convert the largest • part of the mercaptans to H2S, then the gas with high content of mercaptans, hydrogenated, is fed to a second absorption step in which the gas with high content of mercaptans is separated in a first gas stream rich in H2S, the which fed to a Claus plant, followed by an oxidation step with H2S to elemental sulfur in the tail gas, and a second gas stream with lower H2S content, second gas stream in which it burns. Surprisingly, it has been found that with the method according to the invention, large gas streams can be purified in a very efficient manner, while at the same time the requirements can be satisfied with respect to the emission of harmful substances and the efficiency of sulfur recovery. T ^ * According to the invention, the gas with high mercaptan content is first passed through a hydrogenation reactor, whereby the mercaptans in the gases are converted to H2S with the help of the hydrogen supplied. Subsequently the gas with high content of mercaptans is separated in the so-called enrichment unit in two other gases, viz, a gas rich in H2S and a gas rich in C02, which contains most of the C02, hydrocarbons and aromatic compounds.

The gas rich in C02 with hydrocarbons and ÍP aromatics present allows proper combustion in a post-combustion plant. The heat released in this post-combustion can be used very useful, for example for the generating current. The gas rich in H2S is passed to the sulfur recovery plant. With this method, the concentration of H2S can easily be increased from 2 to 6 times. This gas rich in H2S can be processed very well in a plant Claus, the great advantage is that the absence of a large part of the C02, hydrocarbons and aromatics does not cause any production of additional gas in the plant after combustion. As a result, the Claus plant can be made much smaller in design, and reach the same times of much higher sulfur recovery. The tail gas obtained from the Claus plant is further processed in a tail gas recovery plant based on the selective oxidation of the sulfur compounds to elemental sulfur. The gas recovery plant of the bottom is preferably the SUPERCLAUS reactor stage. The gases separated from this tail gas desulfurization unit are burned in an afterburner. The heat released can be used in a manner useful for the generation current.

According to the invention, the gas with high content of mercaptans is passed with hydrogen over a hydrogenation reactor containing a metal catalyst with 6 groups and / or eight sulphide groups on a carrier. As the carrier, alumina is preferably used with this type of catalyst, since this material, in addition to the desired thermal stability, also allows a good dispersion of the active component. As material Catalytically active, a combination of cobalt and molybdenum is preferably used. In the hydrogenation step the mercaptans in the gas are converted to H2S with the help of the hydrogen supplied. To limit the undesirable reaction between H2S and C02 at COS and H20, steam is supplied to the hydrogenation step, so that less COS is formed. 'Ss An alternative method to prevent the formation of COS, but without supplying water vapor, is the installation of a preabsorbent before the hydrogenation stage, so that the concentration of H2S in the gas is reduced to less than one quarter. The gas from this preabsorbent is then passed through a hydrogenation reactor, in which all the mercaptans are converted to H2S with the aid of the added hydrogen. The residual H2S is then absorbed selectively in a second absorbent, the second step of absorption. In equilibrium, the same enrichment with H2S is obtained as with a single absorber. With this method, however, the risk of COS formation is totally or largely prevented. According to a preferred embodiment of the invention, the first absorption step is carried out using a chemical, physical or chemical / physical absorption agent, which removes all natural gas contaminants. Preferably, this is an absorption agent which is based on sulfolane, in combination with a secondary and / or tertiary amine. As already indicated, such systems are known and are already being used on a large scale to purify natural gas, especially when natural gas liquefies after purification (for example the procedure with SULFINOL-D). The absorption, as is conventional, is based on a system whereby the contaminants are absorbed into the solvent in a first column, subsequently, when the solvent is loaded with contaminants, this solvent is regenerated in a second column, for example through heating and / or through the reduction of pressure. The temperature at which the absorption takes place is to a large extent dependent on the solvent and the pressure used. At the actual pressures of natural gas from 2 to 100 bar, the absorption temperature is generally 15 to 50 ° C, although outside these ranges Good results can also be obtained. Natural gas is ? k preferably purifies to meet the gas pipeline specifications, which means that in general no more than 10, particularly no more than 5 ppm, of H2S should be present. The gas stream that emanates from the first absorption / desorption, which contains most contaminants such as H2S, aromatics, "- Hydrocarbons and mercaptans, as well as C02, are hydrogenated then in the presence of a suitable catalyst such as Co / Mo on alumina, and hydrogen. Up to this point, however, the gas stream must be heated from the absorption / desorption temperature of about 40 ° C to the temperature of 200 to 300 ° C required for the hydrogenation. This heating preferably occurs indirectly and not with a burner arranged in the current * Gas, as is conventional. In effect, the disadvantage of directly heating is that the direct heating in this case results in a substantial soot formation, which can lead to fouling and clogging in hydrogenation. As indicated above, steps can be taken to reduce the formation of COS. In the second stage of absorption, the hydrogenated gas is divided into a gas rich in H2S and a gas poor in H2S. This Absorption preferably occurs using a solvent base of a secondary or tertiary amine, more particularly with an aqueous solution of methyldiethylamine, optionally in combination with an activator thereof, or with a hindered tertiary amine. Such procedures are known and described in the literature (MDEA process, UCARSOL, FLEXSORB-SE, and the like). The way of operating such procedures is comparable to that of the first absorption stage. The degree of enrichment is preferably at least 2 to 6 times or more, which partially depends on the initial concentration of H2S. The degree of enrichment can be fixed through the appropriate choice of absorbent construction. The gas rich in H2S is fed to the thermal stage of the Claus plant. Such a plant is known and the way which operates with respect to temperature and pressure has already * &; been described in detail in the publications cited in the introduction. The gas from the tail of the Claus plant, which still contains residual sulfur compounds, is fed, if desired after the supplemental hydrogenation, to a tail gas processing apparatus, wherein through the selective oxidation of the sulfur compounds, elemental sulfur is formed, which is separated into a suitable plant for such purpose , for example as described in European Patent Application No. 655,414. ß After separation of the sulfur, the remaining gas can be burned, optionally to form steam, and discharged to the atmosphere. The selective oxidation is preferably carried out in the presence of a catalyst which selectively converts the sulfur compounds to elemental sulfur, for example the catalyst described in the European and International Patent Applications mentioned at the beginning. These publications, whose content is incorporated here as a reference, they also indicate the most suitable process conditions, such as temperature and pressure. In general, however, the pressure is not critical, and the temperatures may be between the dew point of the sulfur and about 300 ° C, more particularly less than 250 ° C.

The invention will now be described with reference to two drawings in which the method according to the invention is described in the form of a block diagram. The gas with high mercaptan content, which emanates from a first unit absorption (not shown), in which the contaminated natural gas has been separated, on the one hand, a gas stream with the desired specification and, on the other hand, the gas with high content of mercaptans, is carried in the line 1 at the desired hydrogenation temperature, under the addition of hydrogen and / or carbon monoxide via line 2, before transfer it to the hydrogenation reactor 3. Also, via line 6, steam is fed to line 1 to suppress the formation of carbonyl sulphide in the hydrogenation reactor 3. The hydrogenation reactor 3 the mercaptans and other sulfur compounds organic substances present in the gas are converted to H2S. The gas from the hydrogenation reactor 3, after being cooled, is passed via line 7 to an absorbent of a selective absorption / regeneration plant. In this cooling, the supplied water vapor is condensed and via an evaporator 5 it is recirculated to the hydrogenation reactor 3. The non-absorbed gas components, consisting mainly of carbon dioxide, hydrocarbons (including aromatics) and a low content of H2S, are routed via line 8 to an afterburner 18 before the gas is discharged via the stack 19. The gas mixture rich in H2S coming from the regeneration section of the absorption / regeneration plant 9 is supplied via line 10 to the Claus 11 plant, in which most of the sulfur compounds are converted to elemental sulfur which is discharged via line 12. To increase the efficiency of the Claus plant, the tail gas with frequency is passed via line 13 to a sulfur removal step of the tail gas 14. This stage of sulfur removal can be a known sulfur removal process, such as, for example, a dry bed oxidation step, an absorption step, or a liquid state oxidation step. The air required for oxidation is supplied via the line . The sulfur formed is discharged via line 16. The gas is then passed via line 17 to afterburner 18 before the gas is discharged via the stack 19. ßr As indicated in Fig. 2, the gas with high The mercaptan content, which comes from the first absorption unit (not shown), in which the contaminated natural gas has been inhibited, on the one hand, in a gas stream with the desired specification and, on the other hand, the gas with high mercaptan content, is passed through the line 1 to a preabsorbent 2 of an absorption / regeneration plant, which further comprises a second absorber and a regenerator 9. The gas coming from the preabsorbent 2 is passed via line 3 to the hydrogenation reactor 5 and is carried at the desired hydrogenation temperature under the addition of hydrogen and / or carbon monoxide via line 4. In the hydrogenation reactor 5 the mercaptans and other organic sulfur compounds present in the gas are converted to H2S. The gas from the hydrogenation reactor, after being cooled, it is passed via line 6 to a HE; second absorbent. The non-absorbed gas components, which consist substantially of carbon dioxide, hydrocarbons (including aromatics) and a minimum amount of H2S, are routed via line 8 to 5 afterburner 21 before the gas is discharged via the battery 22 The gas mixture rich in H2S, which comes from regenerator 9, is fed via line 13 to the plant 'Claus 14, in which most of the compounds of Sulfur is converted to elemental sulfur which is discharged via line 15. The regenerated absorption agent is recirculated on the second absorbent 7 and then returned via line 11 to the preabsorbent 2. From the preabsorbent 2 the absorbent loaded with H2S and C02 is returned via line 12 to regenerator 9. To increase the efficiency of the Claus plant, the tail gas is passed via line 16 to the sulfur removal step of the tail gas 18. This stage The removal of sulfur can be a known sulfur removal process such as the dry bed oxidation step, an absorption step or a liquid state oxidation step. The air required for oxidation is supplied via line 17. The sulfur formed is discharged via 19. The gas is then passed via line 20 to the afterburner 21 before the gas is discharged via the stack 22. The invention is described in and by the following non-limiting examples. EXAMPLE 1 An amount of gas with high mercaptan content of 15545 Nm3 / h from the regenerator of a gas purification plant had the following composition at 40 ° C and a pressure of 1.70 bar abs. 9. 0 vol. H2S 60 ppm vol. COS 0. 22 vol. CH3SH 0. 38 vol. C2HsSH 81 53 g, or vol. C02 4. 23 vol. H20 3. 51 vol. Hydrocarbons (from Ci to C17) 1. 08 or vol. Araiátiaos Caipuestos (Bsnsaxv Ibluaio, Xileno) To this gas with high mercaptan content was supplied 3000 Nm3 / h of reducing gas containing hydrogen and carbon monoxide and then heated to 205 ° C to hydrogenate all the mercaptans present to H2S in the hydrogenation reactor which contained metal catalyst with 6 groups and / or eight sulfur groups, in this case Co-Mo catalyst. This gas with a high mercaptan content of 7000 Nm3 / h of steam was also supplied to suppress the formation of COS in the hydrogenation reactor. The temperature of the reactor gas was 226 ° C. The gas with high mercaptan content was then cooled to 46 ° C and the water vapor contained in it condensed. This condensation was recirculated, via an evaporator, to the gas with high mercaptan content, which was passed through the hydrogenation reactor. The amount of gas coming from the hydrogenation reactor, after the condensation of the water vapor supplied, was 18545 Nm3 / h and had the following composition 8. 08% ol. H2S 50 ppm vol * COS 69.78 vol. C02 6.4 vol. H20 2.94 vol., Hydrocarbons (from Cx to Ci7) 0.91 vol. Ccppuestos Aratátiaos (BßTcsx *, Toluexv Xilax >) 1. 03 g. O vol. H2 10.86 g. vol. N2 Subsequently the cooled gas was contacted with an absorber of a gas purification plant with a methyldiethanole solution, so the H2S and a part of the. C02 were absorbed. The amount of gas in the product (gas rich in C02) of the absorbent was 15680 Nm3 / h with the following composition: 74 54 g. - O vol. co2 10 500 ppm vol. H2S 60 ppm vol. COS 6 .78 0. O vol. H20 3. 48 g_ or vol. Hydrocarbons (from Ci to C17) 1. 07 g. ? vol. Amrétiaos Catpuestos (Bexeno, Tolueno, Xileno) 1 .21 g. ? vol. H2 12 86 g. vol. N2 ^ Via a afterburner, this was passed to the pile. After desorption in a regenerator, the gaseous mixture of H2S / C02 with high content of mercaptans (gas rich in H2S) was passed in a sulfur recovery plant. This gaseous mixture of H2S / C02 contributed 2870 Nm3 / h and had the following composition at 40 ° C and 1.7 bar abs. 51 9 g. ? vol. H2S wr 43. 8 o. or vol. C02 4. 3 . ? vol. H20 To the burner of the thermal stage of the sulfur recovery plant were supplied 2975Nm3 / h of air, so that after the second stage of the Claus reactor were present 1.14% by volume of H20 and 0.07% by volume of S02 in the gas of the procedure. The gas The process was then fed to the sulfur removal step of the tail gas, which consisted of a selective H2S oxidation reactor. This gas was supplied with 310 Nm3 / h of air. The entrance temperature of the selective oxidation reactor was 220 ° C and the outlet temperature was 292 ° C. The selective oxidation reactor is filled with catalyst as described in European Patents 242,920 and 409,353 and in International Patent Application WO-A 95/07856. The sulfur formed in the recovery plant of sulfur condensed after each stage and was undone. The outgoing inert gas was passed through an afterburner to the stack. The amount of sulfur was 2094 Kg / h. The sulfurization efficiency based on the gas with high original mercaptan content, which contained 9.0% by volume of H2S, was 97.7%.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following: ^

Claims (10)

1. A method for removing contaminants containing sulfur in the form of mercaptans and H2S from a hydrocarbon gas, which can also contain C02 and higher aliphatic and aromatic hydrocarbons, and recover elemental sulfur, characterized in that in a first step of absorption the contaminants that contain sulfur are 0- removed from the gas, to form on the one hand a stream of 10 gas purified and on the other side a gas with high content of mercaptans, ace with high content of mercaptanQr, which is hydrogenated to convert most of the mercaptans to H2S, later the gas with high content of hydrogenated mercaptans is fed to a second step of

Absorption in which the gas with high mercaptan content is separated in a first gas stream rich in H2S, which is fed to a Claus plant, followed by a step of selective oxidation of H2S to elemental sulfur in the gas of the tail, and a second stream of gas with less amount of 20 H2S, second gas stream which is burned. 2. The method according to claim 1, characterized in that the first absorption step is carried out using a chemical, physical or chemical / physical absorption agent, which removes substantially all the 25 sulfur compounds and C02.

3. The method according to claim 2, characterized in that the absorption agent is based on sulfolane, in combination with a secondary or tertiary amine.

4. The method according to claim 1 or 2, characterized in that the absorption step is carried out using an absorption agent based on a secondary and / or tertiary amine.

5. The method according to claims 1-4, characterized in that the first absorption step is carried out in such a way that the gas contains no more than 10, more particularly no more than 5 ppm of sulfur-containing contaminants. .

6. The method according to claim 5, characterized in that the gas is natural gas, which is optionally liquefied after purification.

7. The method according to claims 1-6, characterized in that the second absorption step is carried out in such a way that the H2S content in the first gas stream is at least 2.5 times, more particularly at least four times greater than the H2S content in the gas with high mercaptan content.

8. The method according to claims 1-7, characterized in that the content of mercaptans in the hydrogenated gas stream is less than 1 ppm.

9. The method according to claims 1-8, characterized in that the hydrogenation occurs in the presence of a catalyst on a support, with a catalytically active component based on at least one Group VIB metal and at least one metal of group VIII of the Periodic System of the Elements, more particularly of a combination of cobalt and molybdenum.

10. The process according to claim 1-9, characterized in that the gas with high mercaptan content is fed to a preabsorbent before the hydrogenation step.