Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
  • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
  • C10G65/04—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including only refining steps

Definitions

• the present invention relates to the field of fuels for combustion engines internal. It relates more particularly to the manufacture of a motor fuel compression ignition.
• the invention relates to a method of transformation of a diesel cut to produce a fuel with a high cetane number, deeply desulfurized.
• the fuel usable in engines must contain a quantity of sulfur less than about 500 parts per million by weight (ppm).
• ppm parts per million by weight
• diesel means both cuts of this type from direct distillation (or straight-run (SR) depending on the English name) of a crude oil, that cuts of this type from different conversion processes and in particular those resulting from the catalytic cracking.
• Hydrodesulfurization is the essential refining process to bring these products with the required sulfur contents.
• US Pat. No. 5,292,428 proposes a process for hydrotreating hydrocarbon feedstocks including gas oils, comprising two or more catalytic zones, with elimination of H 2 S at the outlet of the first zone and addition of fresh hydrogen in the second reactor.
• the elimination of the H2S thus formed is generally carried out by means of an amine washing device.
• the activity of the catalyst in the second catalytic zone is thus improved due to the lower partial pressure of H 2 S.
• VVH volume of charge per volume of catalyst and per hour
• this process has a certain drawback due to the use of a noble metal in the second step linked on the one hand to the cost of such a catalyst and on the other hand to its sensitivity to hydrogen sulfide, the content of which must be limited to the maximum at the end of the first stage if one wishes to obtain a lifetime of this reasonable second stage catalyst.
• the hydrocarbon cut is typically a kerosene and / or a diesel, the initial boiling point of which is understood between about 150 and 250 ° C, and the final boiling point is between about 300 and 400 ° C.
• the process according to the invention uses two hydrodesulfurization zones containing each at least one bed of hydrodesulfurization catalyst containing on a support at at least one non-noble metal from group VIII associated with at least one metal from group VIB.
• the first step a) of deep hydrodesulfurization is usually carried out in a reaction zone comprising at least one fixed bed of catalyst.
• This area can contain several beds of identical or different catalysts from each other.
• step c) is usually carried out in a reaction zone comprising at least one fixed catalyst bed.
• This area can contain several catalyst beds identical or different from each other.
• the different catalytic zones can be arranged in different reactors. Several catalytic zones, except of the first, can be integrated into a single reactor.
• the amount of catalyst used in the first step (step a)) is so preferred from about 10% to about 40% by weight of the total amount of catalyst used in said process and more preferably this amount will be approximately 15% to about 30% by weight of the total amount of catalyst used in said process.
• Step b) of recovery of a liquid charge depleted in hydrogen sulfide and of a gaseous fraction containing at least part of the hydrogen sulfide contained in the total effluent of step a) can be carried out. work by any means known to those skilled in the art.
• this recovery of a gaseous fraction containing at least part of the hydrogen sulphide contained in the total effluent from step a) can be carried out by stripping or entrainment (also called stripping according to English terminology). by at least one gas containing hydrogen under a pressure substantially identical to that prevailing in the first stage and at a temperature of about 100 ° C to about 450 ° C under conditions of formation of a gaseous stripping effluent containing hydrogen and hydrogen sulfide.
• This recovery can also be carried out, for example, by expansion (flash) of the total effluent from step a).
• the gaseous fraction recovered in step b) containing hydrogen sulfide is sent to an at least partial elimination zone of the hydrogen sulfide which it contains, starting from which one recovers purified hydrogen which one recycles at the entry of stage a) of deep hydrodesulfurization.
• the purification of hydrogen, from the gaseous mixture containing hydrogen and hydrogen sulphide coming from the zone of at least partial elimination of hydrogen sulphide is usually carried out according to one or the other of the conventional techniques well known to those skilled in the art and in particular by prior treatment of this gaseous mixture with a solution of at least one amine under conditions allowing the elimination of the hydrogen sulphide by absorption, said amine being most often chosen from the group formed by monoethanolamine, diethanolamine, diglycolamine, diisopropylamine, and methyldiethanolamine.
• the gaseous mixture will be brought into contact with a basic solution, preferably an aqueous solution of an amine chosen from the group mentioned above, which forms with hydrogen sulfide a compound of addition which makes it possible to obtain a purified gas containing proportions of hydrogen sulfide well below 500 ppm by weight and often less than about 100 ppm by weight. Most often the amount of hydrogen sulfide remaining is less than about 50 ppm by weight and very often less than about 10 ppm by weight.
• This method of purifying the gas mixture is a conventional method well known to those skilled in the art and widely described in the literature.
• treatment with an aqueous amine solution is usually carried out at a temperature of from about 10 ° C to about 100 ° C and often from about 20 to about 70 ° C.
• the amount of amine used is such that the hydrogen sulfide to amine molar ratio is from about 0.1: 1 to about 1: 1 and often from about 0.3: 1 to about 0.8: 1 and per example of about 0.5: 1.
• the pressure at which absorption by the amine solution of hydrogen sulfide is carried out is usually from about 0.1 MPa to about 50 MPa, often about 1 MPa at around 25 MPa and most often from around 1 MPa to around 10 MPa.
• the regeneration of the amine solution is conventionally carried out by variation of pressure.
• a hydrogen sulphide adsorption zone comprising at least one reactor and often at least two adsorption reactors containing for example a preferably regenerable screen or for example zinc oxide and operating by example at a temperature from about 10 ° C to about 400 ° C, and often from about 10 ° C to about 100 ° C and most often from about 20 ° C to about 50 ° C under a total pressure of about 0.1 MPa to about 50 MPa, often from about 1 MPa to about 25 MPa and preferably from about 1 MPa to about 10 MPa.
• the adsorption zone comprises two reactors
• one reactor is used to treat the gas while the other is in the process of regenerating or replacing the material that it contains allowing the drying and desulfurization of the mixture gaseous entering said zone.
• the content of hydrogen sulfide in the gas is usually less than 1 ppm by weight and often of the order of a few tens of ppb by weight.
• step a) usually include a temperature from about 240 ° C to about 420 ° C, a total pressure from about 2 MPa to about 20 MPa and an hourly space velocity of liquid charge of about 0.1 to about 5 and that from step c) usually include a temperature from about 240 ° C to about 420 ° C, a total pressure of about 2 MPa to about 20 MPa and a space speed hourly charge of liquid at most equal to approximately the space velocity hourly of charge liquid from step a).
• the catalyst (s) used in the various catalytic zones are hydrodesulfurization catalysts. These catalysts can be catalysts classics such as those described in the prior art and for example one of those described by the applicant in French patent applications FR-A-2197966, FR-A-2583813ou in patent document EP 297949. It is also possible to use commercial catalysts such as those sold by the company PROCATALYSIS. These catalysts each comprise at least one metal or one compound of group VIB metal and / or at least one non-noble metal or compound of non-noble metal from group VIII, on an appropriate mineral support.
• the catalyst support is generally a porous solid.
• This support is usually chosen from the group formed by alumina, silica, silica-aluminas, zeolites, magnesia, titanium oxide TiO 2 and mixtures of at least two of these mineral compounds.
• Alumina is very commonly used.
• the metal of group VIB is usually chosen from the group formed by molybdenum and tungsten, and the group VIII metal is usually selected from the group formed by nickel, cobalt and iron and most often in the group formed by nickel and cobalt. Combinations such as NiMo or CoMo are typical.
• the catalyst used in step a) and that used in step c) each comprise molybdenum or a molybdenum compound in one quantity expressed by weight of metal relative to the weight of the finished catalyst of approximately 2 at 30% and a metal or a metal compound chosen from the group formed by nickel and cobalt in an amount expressed by weight of metal relative to the weight of the about 0.5 to 15% finished catalyst.
• a catalyst comprising, as the group VIII metal, nickel and as metal of group VIB of molybdenum.
• the catalyst used in step a) and that used in step c) each further comprises at least one element chosen from the group formed by silicon, phosphorus and boron or one or more compounds of this or these elements.
• the catalysts used in step a) and in step c) each comprise at least one halogen.
• the quantity halogen is from about 0.1 to about 15% by weight relative to the weight of the finished catalyst.
• Halogen is often chosen from the group formed by chlorine and fluorine and in a particular form the catalysts used will contain chlorine and fluorine.
• the temperature of the various catalytic zones is preferably between 260 and 400 ° C, and more preferably between 280 and 390 ° C.
• the pressures operating procedures are preferably between 2 MPa and 15 MPa and preferably between 2 MPa and 10 MPa.
• the overall hourly space velocity or overall VVH (volume of charge per volume of catalyst and per hour) is between 0.1 and 10 h -1 .
• the time distribution of residence in the catalytic zones is such that the residence time in the first catalytic bed represents at most 50% of the overall residence time.
• Diesel half composed of direct distillation diesel, and half LCO (catalytic cracked diesel) is treated in a one-step process with a single catalyst bed in a reactor.
• the characteristics of this diesel are mentioned in table 1.
• the sulfur content of the gas oil produced stabilizes at a value of 60 ppm, i.e. a desulfurization rate of 99.62%.
• Hydrogen consumption in weight compared to the load is 1.30%.
• the same gas oil is treated using the same catalyst under the same conditions but with an injection of the feedstock through the bottom of the reactor with a VVH of 0.55 h -1 .
• the sulfur content of the gas oil produced stabilizes at a value of 10 ppm, ie a desulfurization rate of 99.94%.
• the hydrogen consumption by weight relative to the charge is 1.70%. It is therefore found in addition to the penalty due to the low VVH employed a large increase in the consumption of hydrogen compared to the implementation according to Example 1 which is disadvantageous from the industrial point of view.
• the first bed consists of 150 cm 3 of HR 448 catalyst, while the second bed consists of 50 cm 3 of HR 448 catalyst.
• the charge rate is 200 cm 3 / h, i.e. a VVH of 1.33 h -1 on the first bed and 4 hrs -1 on the second bed.
• the residence time is generally 1 hour, as in Example 1.
• the process diagram with intermediate stripping of H 2 S between the two catalyst beds allows, under the operating conditions specified above, to obtain a diesel fuel at 30 ppm of sulfur, ie a desulfurization rate of 99.81%.
• the hydrogen consumption by weight relative to the charge is 1.30%.
• a consumption of hydrogen is observed which is substantially identical to that of Example 1 with a desulfurization rate slightly improved compared to that obtained by operating under the conditions specified in Example 1.
• the overall residence time on all of the two beds is 1 hour, with a residence time of 0.5 hour on each of the beds (VVH of 2 h -1 on each of the beds).
• the conditions here are identical to those of Example 4, with the exception of the catalyst volumes which are respectively 50 cm 3 for the first bed and 150 cm 3 for the second bed. For an overall residence time of 1 hour, the residence time is 0.25 hours on the first bed and 0.75 hours on the second bed.
• the method according to the invention is advantageous for carrying out treatment of diesel desulphurization. It becomes particularly advantageous to achieve low sulfur content in diesel, less than 30 ppm (example 4) or even less than 10 ppm (example 5). To obtain a given sulfur specification, the method according to the invention allows markets with higher VVH, and therefore an economy of interesting catalyst for the operator. Furthermore the consumption of hydrogen remains constant which is particularly interesting for the operator.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

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• 2000
  • 2000-03-02 FR FR0002809A patent/FR2804967B1/fr not_active Expired - Fee Related
• 2001
  • 2001-02-09 CA CA002334932A patent/CA2334932A1/fr not_active Abandoned
  • 2001-02-09 EP EP01400331A patent/EP1123961A1/de not_active Ceased
  • 2001-02-09 JP JP2001033596A patent/JP2001279262A/ja not_active Withdrawn
  • 2001-02-12 US US09/780,418 patent/US6855246B2/en not_active Expired - Fee Related

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