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
  • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
  • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
  • C10G45/60—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used
  • C10G45/64—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used containing crystalline alumino-silicates, e.g. molecular sieves

Definitions

• the present invention relates to a process for reducing the amount of cyclic structures present in a gas oil.
• Compounds contributing favourably to the cetane index are paraffins. Naphthenes contribute less favourably to the cetane index, while aromatics are even less desirable from that point of view.
• Several processes are known for increasing the cetane index of a given gas oil, such as hydrocracking and hydrogenation. Hydrocracking has as a disadvantage that part of the feed is converted into undesired lighter products. Hydrogenation comprises conversion of olefinic compounds, in particular aromatic compounds, into the corresponding saturated compounds. The optimum cetane index which is possible for a given gas oil without substantial cracking of molecules, will not be attained in this way.
• the present invention relates to a process for reducing the amount of cyclic structures present in a gas oil, which process comprises contacting a gas oil with hydrogen at elevated temperature and pressure using a catalyst comprising one or more Group VIII noble metal(s) on a support wherein the support comprises a modified Y-type zeolite having a unit cell size between 24.20 and 24.40 A and a SiO2/Al2O3 molar ratio of between 10 and 150 and recovering a gas oil comprising a reduced amount of cyclic structures.
• gas oil is meant a hydrocarbon oil comprising mainly hydrocarbons boiling in the range between 170 and 390 °C and containing at least 25% by weight of hydrocarbons boiling in the range between 250 and 390 °C, which hydrocarbon oil further has a cetane index between 38 and 49.
• a relatively light gas oil is used, i.e. mainly comprising hydrocarbons boiling in the range between 170 and 320 °C.
• hydrotreated gas oils are used as these have a relatively low nitrogen and sulphur content which contributes favourably to the life time of the catalyst.
• Hydrodecyclization is understood to comprise reduction of the amount of cyclic structures present in the gas oil.
• the amount of cyclic structures present is reduced with at least 10%, based on amount of cyclic structures present in the feed preferably with at least 15%.
• No substantial cracking takes place, which means that the gas oil recovered from the process according to the present invention comprises at least 5% by weight of hydrocarbons boiling in the range between the 90% by weight boiling point of the feed gas oil and the final boiling point of the feed gas oil.
• a catalyst comprising one or more Group VIII noble metal(s).
• Metals which can be suitably present are platinum and/or palladium.
• the catalyst comprises between 0.05 and 3% by weight of noble metal(s) based on amount of zeolite. More preferably, the catalyst comprises platinum and palladium in a molar ratio of between 0.25 and 0.75.
• the catalyst further comprises a support comprising a modified Y-type zeolite having a SiO2/Al2O3 molar ratio of between 10 and 150. It has been found that catalysts comprising a relatively low SiO2/Al2O3 molar ratio give surprisingly good results.
• a molar ratio which is preferred is between 15 and 50, more specifically between 20 and 45.
• the unit cell size of the Y-type zeolite applied is between 24.20 and 24.40 A, more specifically between 24.22 and 24.35.
• the hydrodecyclization process can suitably be carried out at a temperature between 150 and 400 °C, preferably at a temperature between 250 and 380 °C.
• the hydrogen partial pressure applied will usually be between 10 and 150 bar, preferably between 30 and 100 bar.
• the catalyst temperature and pressure will generally be chosen in such combination that a gas oil is produced having a cetane index of more than 45, preferably more than 50, and comprising less than 25% by weight of aromatic compounds, preferably less than 20. It was found that even gas oils having a cetane index of more than 50 and comprising less than 5% by weight of aromatic compounds, so-called “green gas oils", can be produced in the present process.
• the cetane index is measured according to ASTM D976.
• the characteristics of the gas oil produced depend on the feed gas oil and the process conditions.
• the cetane index and aromatic content which are aimed at in commercial operation, are determined by economic considerations.
• a hydrotreated straight run gas oil as described in Table 1 was contacted with a catalyst comprising Y-type zeolite having a unit cell size of 24.24 A and a SiO2/Al2O3 molar ratio of 40 and containing 0.3% by weight of platinum and 0.5% by weight of palladium, based on amount of zeolite, at a temperature of 265 °C, a hydrogen partial pressure of 35 bar and a weight hourly space velocity of 1.4 ton/m3.hour.

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• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (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)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Catalysts (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (1)

• 1991
  • 1991-05-09 GB GB919110012A patent/GB9110012D0/en active Pending
• 1992
  • 1992-05-07 DE DE69204206T patent/DE69204206T2/de not_active Expired - Fee Related
  • 1992-05-07 FI FI922069A patent/FI114317B/fi active IP Right Grant
  • 1992-05-07 DK DK92201302.4T patent/DK0512652T3/da active
  • 1992-05-07 JP JP14110192A patent/JP3210729B2/ja not_active Expired - Fee Related
  • 1992-05-07 ES ES92201302T patent/ES2077338T3/es not_active Expired - Lifetime
  • 1992-05-07 NO NO921806A patent/NO304029B1/no unknown
  • 1992-05-07 CA CA002068174A patent/CA2068174C/en not_active Expired - Fee Related
  • 1992-05-07 EP EP92201302A patent/EP0512652B1/de not_active Expired - Lifetime

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