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
  • C10G45/44—Hydrogenation of the aromatic hydrocarbons
  • C10G45/46—Hydrogenation of the aromatic hydrocarbons characterised by the catalyst used
  • C10G45/52—Hydrogenation of the aromatic hydrocarbons characterised by the catalyst used containing platinum group metals or compounds thereof
• • 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
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/08—Jet fuel

Definitions

• the heat of combustion of a hydrocarbon is proportional to the hydrogen to carbon ratio, so that its value will be higher for a saturated cyclic hydrocarbon than for the corresponding aromatic hydrocarbon. Moreover the lower the aromatic content of the fuel, the cleaner and the less harmful will be the combustion thereof. It is also desirable to remove aromatics from illuminating oils and stove oils to reduce the evolution of smoke. Still further, the reduction of the aromatic content of some solvents is of great importance on hygienic grounds since the vapors of aromatic hydrocarbons are toxic.
• catalysts may be used for saturating monoand polycyclic aromatics, for example, nickel on kieselguhr or silica, nickel and tungsten sulphides, and noble metals such as platinum.
• nickel as a catalyst permits the reaction to be carried out under relatively moderate conditions of temperature and pressure.
• its use presents two major inconveniences. Firstly, nickel is very sensitive to sulphur-containing compounds and the poisoning resulting from their presence in the feed is irreversible, and secondly, nickel may not be heated above about 400 C. without losing its catalytic activity. The catalyst activity drops continuously as sulphuracontaining compounds accumulate thereon; and the lack of heat stability of the nickel catalyst does not allow the regeneration of the catalytic activity by the combustion of these poisons.
• Nickel and tungsten sulphides in well defined ratios and deposited on a convenient carrier such as alumina, or without carrier, may also be used as catalysts. These sulphides present the advantage of being insensitive to sulphur-containing compounds but are, however, far less catalytically active than the corresponding pure metals.
• the operating conditions must therefore be more severe, i.e. a higher temperature, lower space velocity and especially, a higher pressure are required. This last condition is essential as satisfactory results can be obtained only at higher pressures, on the order of 100 kg./cm. and upwards.
• Platinum on the other hand, does not present the disadvantages inherent in nickel and tungsten sulphides as will appear in the following examples. Platinum catalysts, however, are poisoned by sulphur. Their use thus requires a very considerable and important diminution of the sulphur present in the :feed in order to permit the hydrogenation to be carried out during long periods of time Without having to regenerate the catalyst.
• the principal advantage of this invention is to provide an improved hydrogenation process for the reduction of aromatics in a petroleum distillate.
• the petroleum distillates of this invention usually contain as a matter of practice a minimum of 0.1 p.p.m. by weight of sulphur, and an aromatic content of about 1 to 99% by volume.
• a continuous method for reducing the aromatic hydrocarbon content of a petroleum distillate having a sulphur content prefer-ably not greater than 300 ppm. by weight and boiling in the range of 60 C. to 35 0 C. comprising hydrogenating said petroleum distillate in the presence of a catalyst, comprising platinum on a silica-alumina catalyst carrier which contains at least by weight of silica.
• the influence of the catalyst carrier might be explained by more or less pronounced activity towards the destructive hydrogenation of sulphur-containing molecules. This explanation is purely theoretical and cannot be regarded as in any way limitative of the invention.
• the catalyst preferably contains between 0.1 and 1% platinum by weight, and even more preferably 0.3 to 0.8% by weight.
• the silica content of the catalyst carrier is from 7 5% to by weight.
• Hydrogenation is desirably caried out under the following conditions.
• Temperature to 400 C., preferably 250 to 350 C.;
• Space velocity 0.1 to 20 v./v./hr., preferably 0.5 to 10 v./v./hr;
• Pressure 5.0 to 70 kg./cm. preferably 20 to 55 kg./cm.
• Hydrogen to hydrocarbon ratio 100 to 3,000 liters hydrogen at normal temperature and pressure (N.T.P.) per liter of liquid feed, preferably to 2,500 liters hydrogen, in English units about 50017,000 s.c.f., preferably 8l5014,000 s.c.f. per barrel of liquid feed.
• the processing may be carried out continuously for very long periods of time.
• the sulphur content may be lowered by hydrogenating the petroleum distillate in the presence of a catalyst comprising cobalt and molybdenum oxides supported on alumina according to processes well known in the refining of petroleum distillates.
• the catalyst activity may drop due to the accidental admission of an excessive amount of sulphur or due to a failure to admit the charge for several hours.
• the initial activity is restored simply by readmitting the initial charge and/ or increasing the reaction temperature to 400 C., which is a. temperature much higher than the thermodynamically optimum one, all the other conditions being kept constant, i.e. pressure, hydrogen to hydrocarbon ratio, space velocity, these conditions being the same as for the reaction itself.
• Example 1 A petroleum distill-ate was hydrogen pretreated, according to a technique well known in refinery operations, in order to lower its sulphur content. Charges with various sulphur contents, mentioned hereunder, were obtained by blending treated and untreated distillates, the characteristics of which were as follows- Untreated Treated distillate distillate Specific gravity C./4 C 0.787 0.786 A.S.T.M. Distillation:
• Aromatics percent vol 17 17 Olefins 0 0 Satur es 83 83 Sulphur content, percent weight 0. 200 1 0.0001
• Hydrogen to hydrocarbon ratio 500 liters hydrogen at normal temperature and pressure (N.T.P.) per liter of liquid feed.
• Catalyst A 0.75% platinum by weight supported on alumina
• Catalyst B 0.75 platinum by weight supported on silicaalumina having a silica to alumina ratio of 86 to 14 by weight;
• Catalyst C 0.75% platinum by weight supported on alumina silica added having a silica to alumina ratio of 12 to 88 by Weight.
• Example 2 A charge containing 40 p.p.m. of sulphur and obtained as described in Example 1, was submitted to hydrogenation in a fixed bed of a catalyst containing 0.75% by weight of platinum on a silica-alumina carrier having a silica to alumina ratio of 86 to 14 by weight. barrels of this feed per pound of catalyst were hydrogenated in a continuous manner using the following conditions:
• H /hydrocarbon 500 1. H N.T.P./l. liquid feed.
• the smoke point which is easily and quickly determined is used to evaluate the degree of aromatic hydrogenation.
• This hydrogenation in accordance with our invention performed on a feed having a smoke point of 26 mm. which corresponds for this feed to an aromatic content of 17% by volume as it may be read in Example 1, leads to a product having a smoke point of 30 mm. which corresponds to an aromatic content of about 10% by volume.
• This example illustrates that the hydrogenation process in accordance with our invention, that is to say in the presence of a catalyst containing 0.75% by weight of platinum on a silica-alumina carrier having a silica to alumina ratio of 86 to 14 by weight and in the selected operating conditions, may :be carried out in a continuous manner on a very large volume of feed without any loss of catalytic activity and with a very substantial lowering of the aromatic content of the feed.
• Example 3 It is of the utmost importance to have a catalyst capable of tolerating charges which contain accidentally a very high sulphur content, and which activity of the catalyst may be regenerated without using a complicated process such as the elimination of the impurities by combustion.
• Example 4 Treating at the 400 C. temperature which favors dehydrogenation rather than hydrogenation is also suitable to restore the initial catalyst activity following a drop of activity due to a feed and/ or hydrogen failure for a few hours, the reactor being kept at the reaction temperature.
• the reason for the drop of activity under these conditions is not well understood but could be due to an accumulation of products on the catalyst.
• a charge containing 25 p.p.m. sulphur was treated under the conditions of EX- ample 1 in the presence of catalyst B; the smoke point of the product was 35 mm. After 24 hours processing the liquid flow was stopped and the reactor was kept for 12 hours under hydrogen pressure. The charge was next readmitted; the smoke point of the product was only 30 mm. The temperature was then raised to 400 C.
• the smoke point of the product was 38 mm., thus higher than initially; after about 5 hours processing, the smoke point stabilized at the initial value, i.e. 35 mm.
• This invention is particularly advantageous for the reduction of the aromatic content of jet fuel, kerosene, diesel fuel, and gas oil.
• a continuous process for reducing the aromatic hydrocarbon content of a petroleum fraction boiling in the range of about 60 C. to 350 C. having a substantial sulphur content not higher than 300 parts per million by weight which process comprises hydrogenating said fraction to obtain a substantial hydrogenation of aromatics at a temperature of about 100 to 400 C., at a pressure of about to 1,000 p.s.i.-g., in the presence of about 500 to 17,000 s.c.f. of hydrogen per barrel of liquid feed in contact with a catalyst comprising 0.1 to 1.0% by weight of platinum supported on an active silica-alumina carrier containing from to by weight of silica and at a space velocity of about 0.1 to 20 v./v./hr.

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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)
• Catalysts (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (11)

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Citations (3)

• 0
  • BE BE642626D patent/BE642626A/xx unknown
• 1963
  • 1963-04-11 GB GB14713/63A patent/GB1021321A/en not_active Expired
• 1964
  • 1964-02-03 DE DE19641470591 patent/DE1470591A1/de not_active Withdrawn
  • 1964-04-03 US US357317A patent/US3269939A/en not_active Expired - Lifetime

Patent Citations (3)

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