Method for trapping mercaptans using macropore trapping mass and mesopore trapping mass

Abstract

A process for capturing mercaptans contained in a sulfur-containing hydrocarbon feedstock, the process being carried out at a temperature between 40°C and 250°C, a pressure between 0.2MPa and 5MPa, and an hourly space velocity, defined as the volumetric flow rate of the feedstock at the inlet per volume of the capture mass, of 0.1 h -1 ~50h -1 in the presence of a capture mass comprising an active phase based on at least one Group VIII, IB or IIB metal and a mesoporous or macroporous support, said support being selected from the group consisting of alumina, silica, silica-alumina and clay, said capture mass being 120 ml. 2 / g~350m 2 / g specific surface area, The volume of mesopores having a diameter of 2 nm or more and less than 50 nm corresponds to 40% by volume to 70% by volume of the total pore volume of the capture mass; The volume of macropores having a diameter of 50 nm or more corresponds to 30% to 60% by volume of the total pore volume of the capture mass; process.

Description

[Technical field]

[0001] The present invention relates to the field of hydrotreating gasoline fractions, in particular gasoline fractions coming from fluidized bed catalytic crackers. More particularly, the present invention relates to a process for capturing mercaptan-type compounds contained in a hydrocarbon feedstock in the presence of specific trapping masses. [Background technology]

[0002] Automotive fuel standards require a significant reduction in the sulfur content of these fuels, especially gasoline. This reduction is aimed at limiting the content of sulfur and nitrogen oxides in motor vehicle exhaust gases in particular. Gasoline fuel standards, in force since 2009 in Europe, set a maximum sulfur content of 10 parts per million (ppm) by weight. Such standards are also in force in other countries, e.g. the United States and China, which have required the same sulfur content limits since January 2017. To achieve these standards, gasoline must be treated through a desulfurization process.

[0003] The main source of sulfur in the gasoline base is "cracked" gasoline, which is the gasoline fraction obtained mainly from the catalytic cracking process of atmospheric or vacuum residues of crude oil. The catalytic cracking fraction constitutes on average 40% of the gasoline base and actually accounts for more than 90% of the sulfur content in gasoline. Therefore, a desulfurization step of the catalytic cracked gasoline is necessary to produce low-sulfur gasoline. Other sources of gasoline that may contain sulfur include coker gasoline, visbreaker gasoline, and, to a lesser extent, gasoline obtained from atmospheric distillation or steam cracking.

[0004] To remove sulfur from gasoline fractions, gasoline with high sulfur content must be specially treated by desulfurization in the presence of hydrogen. These are called hydrodesulfurization (HDS) processes. However, these gasoline fractions, more specifically catalytic cracking (FCC) gasoline, contain a lot of unsaturated compounds in the form of monoolefins (about 20% to 50% by weight), diolefins (0.5% to 5% by weight) and aromatics, which contribute to a good octane number. These unsaturated compounds are unstable and react during hydrodesulfurization. Diolefins polymerize during hydrodesulfurization to form gums. This gum formation gradually deactivates the hydrodesulfurization catalyst or gradually clogs the reactor. As a result, diolefins must be removed by hydrotreating before these gasolines can be subjected to any processing. Conventional processing processes non-selectively desulfurize gasoline by hydrogenating most of the monoolefins, which results in high octane number losses and high hydrogen consumption. Modern hydrodesulfurization processes make it possible to desulfurize cracked gasolines rich in monoolefins while limiting the hydrogenation of the monoolefins and thus the loss of the octane number, as described, for example, in EP-A-1 077 247 and EP-A-1 174 485.

[0005] However, if the desulfurization of the cracked gasoline needs to be very thorough, some of the olefins present in the cracked gasoline will be hydrogenated on the one hand and will form mercaptans on the other hand, resulting in the formation of H 2 S. This group of compounds, represented by the chemical formula R-SH, where R is an alkyl group, is generally called recombined mercaptans and accounts for 20% to 80% by weight of the residual sulfur in desulfurized gasoline. The reduction of the content of recombined mercaptans may be achieved by catalytic hydrodesulfurization, but this leads to hydrogenation of most of the monoolefins present in the gasoline, greatly reducing the octane number of the gasoline and also leading to excessive consumption of hydrogen. Furthermore, it is known that the lower the target sulfur content, i.e., the more thoroughly one tries to remove the sulfur compounds present in the feedstock, the greater the proportional reduction in octane number due to hydrogenation of monoolefins in the hydrodesulfurization process.

[0006] For these reasons, it is desirable to treat this partially hydrodesulfurized gasoline by means of a carefully selected adsorption technique capable of simultaneously removing the unconverted sulfur compounds and recombined mercaptans originally present in the cracked gasoline, without hydrogenating the monoolefins present, in order to maintain the octane number.

[0007] Various solutions have been proposed in the literature to extract these mercaptans from hydrocarbon fractions, either through adsorption-type processes or by combining hydrodesulfurization or adsorption steps, but more efficient trapping masses for mercaptan extraction are still needed to suppress the hydrogenation reactions that cause the reduction of the octane number of the target gasoline.

[0008] For example, US Patent Application 2003 / 0188992 describes a method for desulfurizing olefinic gasoline by treating the gasoline in an initial hydrodesulfurization step, followed by a polishing step to remove mercaptan-type sulfur compounds, which consists primarily of solvent extraction of the mercaptans by washing.

[0009] US Pat. No. 5,866,749 proposes a solution for the removal of elemental sulfur and mercaptans contained in olefinic fractions by passing the mixture to be treated over reducing metals selected from groups IB, IIB and IIIA of the periodic table, at temperatures below 37° C.

[0010] US Pat. No. 6,579,444 presents a process for removing sulfur from gasoline, or the sulfur remaining in partially desulfurized gasoline, based on the use of solids containing cobalt and a group VI metal.

[0011] US Patent Application 2003 / 0226786 presents a process for desulfurizing gasoline by adsorption and a method for regenerating the adsorbent. The adsorbent envisaged is any hydroprocessing catalyst, more particularly a solid containing a group VIII metal, either alone or mixed with a group VI metal, and containing between 2% and 20% by weight of the group VIII metal.

[0012] French Patent No. 2908781 discloses a process for capturing sulfur compounds from a partially desulfurized hydrocarbon feedstock in the presence of an adsorbent containing at least one metal of group VIII, IB, IIB or IVA, the adsorbent being used in reduced form in the absence of hydrogen and at temperatures above 40°C.

[0013] The applicant has surprisingly found that it is possible to improve the performance of the mercaptan capture process by using a capture mass that is meso- and macro-porous in combination with a high specific surface area, thereby significantly increasing the mercaptan retention capacity. Without wishing to be bound by any theory, the synergistic effect between a high specific surface area and the specific pore distribution of the capture mass makes it possible, on the one hand, to ensure a good dispersion of the metal elements within said capture mass, and, on the other hand, to reduce the phenomenon of restricted mobility of the sulfur-containing compounds to be captured. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] European Patent Application Publication No. 1077247 [Patent Document 2] European Patent Application Publication No. 1174485 [Patent Document 3] U.S. Patent Application No. 2003 / 0188992 [Patent Document 4] U.S. Pat. No. 5,866,749 [Patent Document 5] U.S. Patent No. 6,579,444 [Patent Document 6] US Patent Application No. 2003 / 0226786 [Patent Document 7] French Patent No. 2908781 Summary of the Invention [Means for solving the problem]

[0015] The present invention relates to a process for capturing mercaptans contained in an optionally partially desulfurized sulfur-containing hydrocarbon feed resulting from a catalytic hydrodesulfurization step, the process being carried out at a temperature between 40° C. and 250° C., at a pressure between 0.2 MPa and 5 MPa, and with an hourly space velocity, defined as the volumetric flow rate of the feed at the inlet per volume of the capture mass, of 0.1 h -1 ~50h -1 in the presence of a capture mass comprising an active phase based on at least one Group VIII, IB or IIB metal and a mesoporous or macroporous support, said support being selected from the group consisting of alumina, silica, silica-alumina and clay, said capture mass being 120 ml. 2 / g~350m 2 / g specific surface area, The volume of mesopores having a diameter of 2 nm or more and less than 50 nm corresponds to 40% by volume to 70% by volume of the total pore volume of the capture mass; The volume of macropores having a diameter of 50 nm or more corresponds to 30% to 60% by volume of the total pore volume of the capture mass; Regarding the process.

[0016] According to one or more embodiments, the capture mass is 150 m 2 / g~300m 2 / g.

[0017] According to one or more embodiments, the volume of mesopores with a diameter of 2 nm or more and less than 50 nm represents 45% to 65% by volume of the total pore volume of the capture agglomerate.

[0018] According to one or more embodiments, the volume of macropores with a diameter of 50 nm or more represents 35% to 55% by volume of the total pore volume of the capture mass.

[0019] According to one or more embodiments, the content of the group VIII, IB or IIB element is between 10% and 80% by weight based on the total weight of the capture mass.

[0020] According to one or more embodiments, the Group VIII, IB or IIB metal is selected from nickel, copper or zinc.

[0021] According to one or more embodiments, the metal is nickel.

[0022] According to one or more embodiments, the content of elemental aluminum and / or elemental silicon in the capture mass is between 5% and 45% by weight based on the total weight of the capture mass.

[0023] According to one or more embodiments, the capture agglomerate has a total pore volume of between 0.1 ml / g and 0.7 ml / g as measured by mercury porosimetry.

[0024] According to one or more embodiments, the hydrocarbon feedstock is a feedstock that has been partially desulfurized by a catalytic hydrodesulfurization process.

[0025] According to one or more embodiments, the hydrocarbon feedstock being treated is a partially desulfurized catalytically cracked gasoline having a boiling point below 350° C., containing 5% to 60% by weight of olefins and less than 100 ppm by weight of sulfur, based on the total weight of the feedstock. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Below, the groups of chemical elements are indicated according to the CAS classification (CRC Handbook of Chemistry and Physics, published by CRC Press, editor in chief DR Lide, 81st edition, 2000-2001). For example, group VIII according to the CAS classification corresponds to the metals in columns 8, 9 and 10 according to the new IUPAC classification.

[0027] The BET specific surface area is measured by nitrogen physisorption according to standard ASTM D3663-03, the method described in "Adsorption by Powders & Porous Solids: Principles, Methodology and Applications" by Rouquerol F., Rouquerol J. and Singh K., Academic Press, 1999.

[0028] In this specification, following the IUPAC convention, "micropores" are understood to mean pores with a diameter of less than 2 nm, i.e. less than 0.002 μm, "mesopores" to mean pores with a diameter of more than 2 nm, i.e. more than 0.002 μm and less than 50 nm, i.e. less than 0.05 μm, and "macropores" to mean pores with a diameter of 50 nm or more, i.e. more than 0.05 μm.

[0029] In the following description of the invention, the "total pore volume" (TPV) of the capture mass or support is understood to mean the volume measured by mercury intrusion porosimetry according to standard ASTM D4284-83, at a maximum pressure of 4000 bar (400 MPa), with a surface tension of 484 dynes / cm and a contact angle of 140°. The wetting angle was taken to be 140° according to the recommendations of Jean Charpin and Bernard Rasneur, Techniques of the Engineer, Analysis and Characterization Treatise, pages 1050-5.

[0030] For better accuracy, the values ​​of total pore volume in ml / g given in the following text correspond to the value of the total mercury volume in ml / g measured on a sample (total pore volume measured by mercury intrusion porosimetry) minus the value of the mercury volume in ml / g measured on the same sample for a pressure equivalent to 30 psi (approximately 0.2 MPa).

[0031] The macropore and mesopore volumes are measured by mercury intrusion porosimetry according to standard ASTM D4284-83 at a maximum pressure of 4000 bar (400 MPa), a surface tension of 484 dynes / cm and a contact angle of 140°.

[0032] The value at which mercury fills all intragranular voids is set to 0.2 MPa, and it is considered that mercury penetrates into the pores of the sample when this value is exceeded.

[0033] The macropore volume of the entrapment mass or support is defined as the cumulative volume of mercury introduced at pressures between 0.2 MPa and 30 MPa, corresponding to the volume contained in pores with an apparent diameter of more than 50 nm.

[0034] The mesopore volume of the entrapment mass or support is defined as the cumulative volume of mercury introduced at a pressure between 30 MPa and 400 MPa, and corresponds to the volume contained in pores with an apparent diameter of more than 2 nm and less than 50 nm.

[0035] When the increase in pore volume, measured by mercury porosimetry, is plotted as a function of pore diameter, the porosity modes correspond to the inflection points of the depicted function.

[0036] The content of metallic elements (group VIII, IB or IIB metals) is measured by X-ray fluorescence.

[0037] (Mercaptan capture) The present invention relates to a process for capturing mercaptans contained in a sulfur-containing hydrocarbon feedstock, said feedstock having been advantageously partially desulfurized by a catalytic hydrodesulfurization step in the presence of a capture mass.

[0038] The mercaptan capture step is generally carried out at a temperature of 40°C to 250°C, preferably 100°C to 250°C, and more preferably 130°C to 240°C.

[0039] The process generally lasts for 0.1 h. -1 ~50h -1 , preferably 0.5h -1 ~20h -1 , preferably 0.5h -1 ~10h -1 The process is carried out at an hourly space velocity (defined as the volumetric flow rate of the feed at the inlet per volume of the captured mass).

[0040] The mercaptan capture process is generally carried out in the absence of hydrogen. The feed should preferably remain liquid, which requires sufficient pressure above the vaporization pressure of the feed. The mercaptan capture process is generally carried out at a pressure of 0.2 MPa to 5 MPa, preferably 0.2 MPa to 2 MPa.

[0041] Advantageously, the reaction section of the capture process comprises 2 to 5 reactors, referred to by the term PRS for Replaceable Reactor System or "Lead & Lag", which are operated in a replaceable mode.

[0042] The sulfur-containing hydrocarbon feedstock, which is optionally partially desulfurized, is preferably a gasoline containing olefinic compounds, preferably a gasoline fraction obtained from a catalytic cracking process. The treated hydrocarbon feedstock generally has a boiling point below 350° C., preferably below 300° C., very preferably below 250° C. Preferably, the feedstock contains 5% to 60% by weight of olefins, based on the total weight of said feedstock. Preferably, the hydrocarbon feedstock contains less than 100 ppm by weight of sulfur, preferably less than 50 ppm by weight, based on the total weight of said feedstock. Preferably, the partially desulfurized hydrocarbon feedstock contains less than 50 ppm by weight of sulfur in the form of mercaptans, preferably less than 30 ppm by weight of sulfur in the form of mercaptans, based on the total weight of the feedstock.

[0043] Preferably, the feedstock to be treated is subjected to a partial desulfurization treatment prior to the mercaptan capture process, which step consists of contacting the sulfur-containing feedstock fraction with hydrogen in one or more hydrodesulfurization reactors arranged in series, which contain one or more catalysts suitable for carrying out hydrodesulfurization. Preferably, the operating pressure of this step is generally between 0.5 MPa and 5 MPa, very preferably between 1 MPa and 3 MPa, and the temperature is generally between 200°C and 400°C, very preferably between 220°C and 380°C. Preferably, the amount of catalyst used in each reactor is generally greater than m3 per hour under standard conditions. 3 The flow rate of gasoline to be processed is expressed as 1 m 3 The ratio of catalyst to the number of catalysts is 0.5h. -1 ~20h -1 , very preferably 1h -1 ~10h -1 Preferably, the hydrogen flow rate is generally in the range of 100 to 2000 m3 per hour under standard conditions. 3 Hydrogen flow rate (Nm 3 / h) and m per hour 3 The ratio of the flow rate of the raw material to be treated, expressed as 50 Nm 3 / m 3 ~1000Nm 3 / m 3 , very preferably 70Nm 3 / m 3~800Nm 3 / m 3 Preferably, this step is carried out selectively, i.e. with the aim of hydrodesulfurization, i.e. with a degree of hydrogenation of the monoolefins of less than 80% by weight, preferably less than 70% by weight, very preferably less than 60% by weight.

[0044] The degree of desulfurization achieved in this hydrodesulfurization step is generally greater than 50%, preferably greater than 70%, so that the hydrocarbon fraction used in the mercaptan capture step contains less than 100 ppm by weight of sulfur, preferably less than 50 ppm by weight of sulfur.

[0045] In the preliminary hydrodesulfurization step, any hydrodesulfurization catalyst can be used. Preferably, a catalyst is used that has a high selectivity for hydrodesulfurization reactions compared to olefin hydrogenation reactions. Such a catalyst comprises at least one porous inorganic support, a group VIB metal, a group VIII metal. The group VIB metal is preferentially molybdenum or tungsten, and the group VIII metal is preferentially nickel or cobalt. The support is generally selected from the group constituted by alumina, silica, silica-alumina, silicon carbide, titanium oxide, alone or in a mixture with alumina or silica-alumina, and magnesium oxide, alone or in a mixture with alumina or silica-alumina. Preferably, the support is selected from the group constituted by alumina, silica and silica-alumina. Preferably, the hydrodesulfurization catalyst used in the additional hydrodesulfurization step has the following characteristics: The content of the Group VIB element is 1% by weight to 20% by weight of the oxide of the Group VIB element based on the weight of the catalyst. The content of the Group VIII element is 0.1% by weight to 20% by weight of the oxide of the Group VIII element based on the weight of the catalyst. The molar ratio of (Group VIII element / Group VIB element) is 0.1 to 0.8.

[0046] If the metal is cobalt or nickel, the metal content is expressed as CoО and NiО, respectively. If the metal is molybdenum or tungsten, the metal content is expressed as MoО, respectively. 3 , WO 3 It is expressed as:

[0047] A highly preferred hydrodesulfurization catalyst contains cobalt and molybdenum and has the above-mentioned characteristics. In addition, the hydrodesulfurization catalyst may contain phosphorus. In this case, the phosphorus content is preferably 0.1 wt% to 10 wt% P based on the total weight of the catalyst. 2 O 5 and the molar ratio of phosphorus to Group VIB element is 0.25 or more, preferably 0.27 or more.

[0048] Preferably, the feedstock being treated is subjected to a complementary polishing hydrodesulfurization treatment after the partial desulfurization treatment and before the mercaptan capture process. The polishing hydrodesulfurization step is primarily intended to convert the recombined mercaptans produced during the partial desulfurization treatment into at least partially olefins and H. 2 The first hydrodesulfurization step is mainly used to break down most of the sulfur compounds into H 2 The remaining sulfur compounds are essentially refractory sulfur compounds, whereas the H produced is hydrodesulfurized to convert them to S. 2 This is a recombined mercaptan produced by the addition of S.

[0049] The polishing hydrodesulfurization step is generally carried out at a temperature between 280° C. and 400° C., preferably between 300° C. and 380° C., preferably between 310° C. and 370° C. The temperature of this polishing step is generally at least 5° C. higher, preferably at least 10° C. higher, very preferably at least 20° C. higher than the temperature of the first hydrodesulfurization step. This step is generally carried out for 0.5 h. -1 ~20h -1 , preferably for 1 h -1 ~10h -1 The process is generally carried out at an hourly space velocity (defined as the volumetric flow rate of the feed at the inlet per volume of catalyst) of 10 ...3 Hydrogen flow rate (Nm 3 / h) and m per hour 3 The ratio of the flow rate of the raw material to the flow rate of the processed material is 10 Nm 3 / m 3 ~1000Nm 3 / m 3 , preferably 20 Nm 3 / m 3 ~800Nm 3 / m 3 The hydrogen flow rate is set so that

[0050] The process is generally carried out at a pressure between 0.5 MPa and 5 MPa, preferably between 1 MPa and 3 MPa.

[0051] In the polishing hydrodesulfurization step, any hydrodesulfurization catalyst can be used. Preferably, the catalyst comprises at least one porous inorganic support and a group VIII metal. The group VIII metal is preferentially nickel. The support is generally selected from the group constituted by alumina, silica, silica-alumina, silicon carbide, titanium oxide, alone or mixed with alumina or silica-alumina, and magnesium oxide, alone or mixed with alumina or silica-alumina. Preferably, the support is selected from the group constituted by alumina, silica and silica-alumina. Preferably, the hydrodesulfurization catalyst used in the polishing hydrodesulfurization step has the following characteristics: The content of the Group VIII element is 0.1% by weight to 30% by weight of the oxide of the Group VIII element based on the weight of the catalyst. · The support used is an alumina-based support.

[0052] Preferably, the hydrocarbon feedstock after polishing hydrodesulfurization treatment contains less than 100 ppm by weight of sulfur derived from organic compounds, preferably less than 50 ppm by weight of sulfur derived from organic compounds, especially in the form of mercaptans and sparingly soluble sulfur compounds.

[0053] At the end of the hydrodesulfurization process, the effluent is treated with dissolved H 2Hydrogen and H by any method known to those skilled in the art (desorber, stabilization column, etc.) are added to recover a liquid effluent in which S represents at most 30 wt.%, further at most 20 wt.%, further at most 10 wt.% of the total sulfur present in the hydrocarbon fraction to be processed downstream by the mercaptan capture process. 2 A step of separating S is carried out.

[0054] (captured mass) The capture mass used in the context of the process according to the invention comprises an active phase based on at least one group VIII, IB or IIB metal and a mesoporous or macroporous support, the support being selected from the group consisting of alumina, silica, silica-alumina and clay, the capture mass being 120 ml or less. 2 / g~350m 2 / g specific surface area, The volume of mesopores having a diameter of 2 nm or more and less than 50 nm corresponds to 40% by volume to 70% by volume of the total pore volume of the capture mass; The volume of macropores having a diameter of 50 nm or more corresponds to 30% by volume to 60% by volume or less of the total pore volume of the capture mass.

[0055] The content of group VIII, IB or IIB elements is preferably between 10% and 80% by weight, preferably between 20% and 70% by weight, very preferably between 30% and 70% by weight, relative to the total weight of the capture mass.

[0056] Preferably, said group VIII, IB or IIB metal is selected from nickel, copper or zinc. Highly preferably, said metal is nickel.

[0057] The capture mass also comprises a support selected from the group consisting of alumina, silica, silica-alumina and clay. The content of elemental aluminum and / or elemental silicon in the capture mass is preferably between 5% and 45% by weight, highly preferably between 5% and 30% by weight, based on the total weight of the capture mass.

[0058] According to one variant, the capture mass used according to the invention may contain at least one group IA or IIA element, preferably sodium or calcium. If the capture mass contains at least one group IA or IIA element, its content is preferably between 0.01% and 5% by weight, very preferably between 0.02% and 2% by weight, relative to the total weight of the capture mass.

[0059] The capture mass used in accordance with the present invention is 120 mm 2 / g~350m 2 / g, preferably 150m 2 / g~300m 2 / g, more preferentially 175m 2 / g~270m 2 / g.

[0060] The capture agglomerates used according to the invention preferably have a total pore volume measured by mercury porosimetry of from 0.1 ml / g to 0.7 ml / g, preferably from 0.2 ml / g to 0.6 ml / g.

[0061] According to the present invention, the volume of mesopores having a diameter of 2 nm or more and less than 50 nm corresponds to 40 vol. % to 70 vol. %, preferably 45 vol. % to 65 vol. %, of the total pore volume of the captured agglomerate.

[0062] According to the invention, the volume of macropores having a diameter of 50 nm or more corresponds to 30% to 60% by volume, preferably 35% to 55% by volume, of the total pore volume of said trapped agglomerate.

[0063] The capture mass used according to the invention is advantageously in the form of grains having an average diameter between 0.5 and 10 mm. The grains may have any shape known to the person skilled in the art, for example, beads (preferably having a diameter between 1 and 6 mm), extrudates, tablets or hollow cylinders. Preferably, the capture mass is in the form of extrudates having an average diameter between 0.5 mm and 10 mm, preferably between 0.8 mm and 3.2 mm, or in the form of beads having an average diameter between 0.5 mm and 10 mm, preferably between 1.4 mm and 4 mm. The term "average diameter" of the extrudates is understood to mean the average diameter of the circle circumscribing the cross section of these extrudates.

[0064] The capture mass used in the context of the process according to the invention can be prepared according to any method known to the person skilled in the art, for example by dry impregnation of a shaped porous inorganic support with the active phase precursor or by kneading the active phase precursor with the structured phase precursor and then shaping.

[0065] Advantageously, the capture agglomerates undergo an activation step so that the active phase is at least partially reduced. This treatment makes it possible to form metal particles of group VIII, IB or IIB elements in the zero-valent state. The reducing gas is preferably hydrogen. Hydrogen may be used pure or in a mixture, for example a mixture of hydrogen / nitrogen, hydrogen / argon or hydrogen / methane. If hydrogen is used in a mixture, any ratio may be envisaged. The reduction treatment is preferentially carried out at a temperature between 100° C. and 500° C., preferably between 100° C. and 450° C. The duration of the reduction treatment is generally between 1 h and 40 h, preferably between 1 h and 24 h. The ramp-up to the desired reduction temperature is generally slow, for example set between 0.1° C. / min and 10° C. / min, preferably between 0.3° C. / min and 7° C. / min. If the step of activating the capture agglomerates is carried out ex situ, i.e. outside the reactor of the mercaptan capture process according to the invention, it is advantageous to carry out a passivation step to protect the capture agglomerates. This passivation step can be carried out in the presence of an oxidizing gas according to any method known to those skilled in the art. After the passivation step, the final activation step is advantageously carried out in situ, i.e. in the reactor of the mercaptan capture process according to the invention, under a stream of a reducing gas such as hydrogen or under the stream of the feedstock to be treated, at a temperature between 100° C. and 300° C., preferably between 100° C. and 250° C.

[0066] The invention is illustrated by the following examples, without limiting its scope. EXAMPLES

[0067] Example 1: Capture mass A (not according to the invention) The alumina support (sold by Axens®) has a diameter of 1.4 mm to 4 mm and a specific surface area of ​​70 m 2 / g and a pore volume of 0.63 ml / g, and is provided in the form of beads as follows: 63% of the total pore volume of pores has a pore diameter of ≥ 2 nm and < 50 nm. · 37% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0068] A nickel nitrate solution containing 14% Ni by weight (Parchem®) is also provided.

[0069] Capture mass A is prepared by dry impregnation of 50 g of alumina support with 25.6 ml of aqueous nickel nitrate solution, followed by drying in air at 120° C. for 12 hours, and then calcination at 450° C. for 6 hours. The operation of dry impregnation and subsequent heat treatment is repeated five times on the recovered solid.

[0070] Capture mass A contains 34.5% nickel and 28.7% aluminum by weight based on the total weight of the solids. 2 / g and a total pore volume of 0.35 ml / g. 50% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. 50% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0071] Example 2: Capture mass B (not according to the invention) The alumina support has a diameter of 1.6 mm and a specific surface area of ​​213 m 2 / g and a pore volume of 0.53 ml / g in the form of extrudates (sold by Axens®) in the following condition: 100% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. 0% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0072] A nickel nitrate solution containing 14% Ni by weight (Parchem®) is also provided.

[0073] Capture mass B is prepared by dry impregnation of 50 g of alumina support with 21.9 ml of aqueous nickel nitrate solution, followed by drying in air at 120° C. for 12 hours, and then calcination at 450° C. for 6 hours. The operation of dry impregnation and subsequent heat treatment is repeated six times on the recovered solid.

[0074] Capture mass B contains 35.1% nickel and 27.9% aluminum by weight based on the total weight of the solids. 2 / g and a total pore volume of 0.29 ml / g, with the following conditions: 100% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. 0% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0075] Example 3: Capture mass C (not according to the invention) The alumina support has a diameter of 1.6 mm and a specific surface area of ​​78 m 2 / g and a pore volume of 0.78 ml / g in the form of extrudates (sold by Axens®) in the following condition: 100% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. 0% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0076] A nickel nitrate solution containing 14% Ni by weight (Parchem®) is also provided.

[0077] The capture mass C is prepared by dry impregnation of 50 g of alumina support with 30.7 ml of aqueous nickel nitrate solution, followed by drying in air at 120° C. for 12 hours, and then calcination at 450° C. for 6 hours. The operation of dry impregnation and subsequent heat treatment is repeated four times on the recovered solid.

[0078] Capture mass C contains 35.0% nickel and 28.9% aluminum by weight based on the total weight of the solids. 2 / g and a total pore volume of 0.43 ml / g, with the following conditions: 100% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. 0% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0079] Example 4: Capture mass D (not according to the invention) The alumina support has a diameter of 1.4 mm to 4 mm and a specific surface area of ​​11 m 2 / g and a pore volume of 0.53 ml / g beads (sold by Axens®) in the following condition: 2% of the total pore volume of the pores has a diameter greater than or equal to 2 nm and less than 50 nm. · 98% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0080] A nickel nitrate solution containing 14% Ni by weight (Parchem®) is also provided.

[0081] Capture mass D is prepared by dry impregnation of 50 g of alumina support with 21.9 ml of aqueous nickel nitrate solution, followed by drying in air at 120° C. for 12 hours, and then calcination at 450° C. for 6 hours. The operation of dry impregnation and subsequent heat treatment is repeated six times on the recovered solid.

[0082] Capture mass D contains 35.1% nickel and 28.5% aluminum by weight based on the total weight of the solids. 2 / g and a total pore volume of 0.29 ml / g, with the following conditions: 1% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. · 99% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0083] Example 5: Capture mass E (according to the present invention) The alumina support has a diameter of 1.4 mm to 4 mm and a specific surface area of ​​264 m 2 / g and a pore volume of 0.49 ml / g beads (sold by Axens®) in the following condition: 65% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. · 35% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0084] A nickel nitrate solution containing 14% Ni by weight (Parchem®) is also provided.

[0085] Capture mass E was prepared by dry impregnation of 50 g of alumina support with 21.9 ml of aqueous nickel nitrate solution, followed by drying in air at 120° C. for 12 h, and then calcination at 450° C. for 6 h. The dry impregnation and heat treatment operations were repeated four times on the recovered solid.

[0086] Capture mass E contains 34.8% nickel and 27.3% aluminum by weight based on the total weight of the solids. 2 / g and a total pore volume of 0.28 ml / g, with the following conditions: 55% of the total pore volume of the pores has a pore diameter of 2 nm or more and less than 50 nm. 45% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0087] Example 6: Capture mass F (according to the invention) The silica-alumina support has a diameter of 1.6 mm and a specific surface area of ​​317 m 2 / g and a pore volume of 0.71 ml / g in the form of extrudates (sold by Sasol®) in the following condition: 79% of the total pore volume of the pores has a pore diameter of ≥ 2 nm and < 50 nm. · 21% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0088] A nickel nitrate solution containing 14% Ni by weight (Parchem®) is also provided.

[0089] Capture mass F was prepared by dry impregnation of 50 g of silica-alumina support with 30.7 ml of aqueous nickel nitrate solution, followed by drying in air at 120° C. for 12 hours and then calcination at 450° C. for 6 hours. The dry impregnation and subsequent heat treatment operations were repeated four times on the recovered solid.

[0090] Capture mass F contains 35.0% nickel, 19.0% aluminum, and 6.5% silica by weight based on the total weight of the solids. 2 / g and a total pore volume of 0.39 ml / g, with the following conditions: 61% of the total pore volume of pores has a pore diameter of ≥ 2 nm and < 50 nm. 39% of the total pore volume of the pores has a pore diameter of 50 nm or more.

[0091] Example 7: Evaluation of the performance of capture masses for the capture of mercaptans The performance evaluation of masses A, B, C, D, E and F is carried out by monitoring their dynamic trapping performance of hexanethiol in a hydrocarbon matrix.

[0092] A test column with a diameter of 1 cm is pre-introduced with 10 ml of the solid to be tested. The solid is reactivated in situ at 400 °C for 2 hours under a hydrogen flow of 10 l / h. A hydrocarbon matrix, called feedstock, is pre-prepared by mixing heptane, 1-hexene and 1-hexanethiol so as to obtain a matrix containing 2000 ppm by weight of sulfur and 10% by weight of olefins. The column containing the solid is then re-introduced at 200 °C under a pressure of 1.7 MPa under a flow of heptane with an hourly space velocity of 8 h -1 The experiment was carried out at 200°C, 1.7 MPa pressure, and 8 h hourly space velocity with heptane flow. -1 The start of the process is when the feed stream is replaced with 100% sulfur. The effluent leaving the column is analyzed to determine the sulfur concentration of the treated matrix.

[0093] The dynamic performance of the solids corresponds to the amount of sulfur that the solids will retain when the effluent concentration corresponds to one-tenth of the sulfur concentration in the feedstock. The results are summarized in Table 1 below.

[0094] [Table 1]

[0095] Only capture masses E and F according to the present invention, which combine a high specific surface area and a specific mesopore and macropore distribution, show high performance in capturing hexanethiol in an olefinic hydrocarbon matrix compared to capture masses A to D not according to the present invention.

Claims

1. 1. A process for capturing mercaptans contained in a sulfur-containing hydrocarbon feedstock, carried out at a temperature of 40°C to 250°C, at a pressure of 0.2 MPa to 5 MPa, and at an hourly space velocity, defined as the volumetric flow rate of the feedstock at the inlet per volume of the capture mass, of 0.1 h-1 to 50 h-1, in the presence of a capture mass comprising an active phase based on at least one Group VIII, IB or IIB metal and a mesoporous or macroporous support, said support being selected from the group consisting of alumina, silica, silica-alumina and clay, said capture mass having a specific surface area of ​​120 m2 / g to 350 m2 / g; the volume of mesopores with a diameter of 2 nm or more and less than 50 nm corresponds to 40% to 70% by volume of the total pore volume of the capture mass; The volume of macropores with a diameter of 50 nm or more corresponds to 30% to 60% by volume of the total pore volume of the capture mass; process.

2. 10. The process of claim 1, wherein the capture mass has a specific surface area of ​​150 m2 / g to 300 m2 / g.

3. 3. The process of claim 1 or 2, wherein the volume of mesopores with diameters of 2 nm or more and less than 50 nm represents 45% to 65% by volume of the total pore volume of the capture mass.

4. 10. The process of claim 1, wherein the volume of macropores having a diameter of 50 nm or greater represents 35% to 55% by volume of the total pore volume of the capture mass.

5. 2. The process of claim 1, wherein the content of the Group VIII, IB or IIB element is 10% to 80% by weight based on the total weight of the capture mass.

6. 2. The process of claim 1, wherein the Group VIII, IB, or IIB metal is selected from nickel, copper, or zinc.

7. 7. The process of claim 6, wherein the metal is nickel.

8. 2. The process of claim 1, wherein the content of elemental aluminum and / or silicon in the capture mass is 5% to 45% by weight relative to the total weight of the capture mass.

9. 10. The process of claim 1, wherein the capture agglomerate has a total pore volume of from 0.1 ml / g to 0.7 ml / g as measured by mercury porosimetry.

10. 10. The process of claim 1, wherein the hydrocarbon feedstock is a feedstock that has been partially desulfurized by a catalytic hydrodesulfurization process.

11. 11. The process of claim 10, wherein the hydrocarbon feedstock to be treated is a partially desulfurized catalytically cracked gasoline having a boiling point below 350°C, containing 5% to 60% by weight of olefins based on the total weight of the feedstock, and containing less than 100 ppm by weight of sulfur.