Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/04—Liquid carbonaceous fuels essentially based on blends of hydrocarbons
  • C10L1/08—Liquid carbonaceous fuels essentially based on blends of hydrocarbons for compression ignition

Definitions

• the invention is directed to a method to increase the cetane number of a gas oil product based on a petroleum derived gas oil by adding to the petroleum derived gas oil an amount of a Fischer-Tropsch derived gas oil.
• petroleum derived gas oils have generally a lower cetane number than gas oils derived from a Fischer-Tropsch process.
• Fischer-Tropsch derived gas oil A problem with Fischer-Tropsch derived gas oil is that they are not widely available and that the cost of preparing such gas oils is believed to be higher than the cost of preparing petroleum derived gas oil for the foreseeable future. There is thus a continuous drive to minimize the amount of Fischer-Tropsch derived gas oil in such a blend while meeting the different final product specifications.
• the fraction x will be a value between 0 and 1 and preferably greater than 0.02.
• the invention is in particular directed to blends wherein the fraction x of Fischer-Tropsch derived gas oil is less than 0.7 and more preferably less than 0.5 and most preferably between 0.05 and 0.3.
• the cetane number of the petroleum derived gas oil and the Fischer-Tropsch derived gas oil as used in the method according the invention may be measured according the normal ASTM D613 method. Because such a method is cumbersome when performing the blending method according to the invention in a refinery environment a more preferred method is by measuring the cetane number by near infrared spectroscopy (NIR) as for example described in detail in US-A-5349188 . Such measurements will include the use of a correlation between the measured spectrum and the actual cetane number of the sample.
• NIR near infrared spectroscopy
• the underlying model is made by correlating the cetane number according to ASTM D613 of a wide variety of petroleum derived samples, Fischer-Tropsch derived gas oil samples and/or their blends with their near infrared spectral data.
• the method according to the invention is embedded in an automated process control of the blending operation in for example a refinery environment.
• a process control may use so-called quality estimators which will provide, by making use of a model, a real time prediction of the cetane number of the resulting blend from readily available raw process measurements, such as for example the cetane numbers as measured by NIR and the volumetric flows.
• quality estimators is calibrated on-line by making use of for example the method described in detail in WO-A-0206905 .
• the Fischer-Tropsch derived gas oil may be any gas oil, which is prepared from the synthesis product of a Fischer-Tropsch synthesis.
• the gas oil product may be obtained by fractionation of such a Fischer-Tropsch synthesis product or obtained from a hydroconverted (hydrocracking/hydroisomerisation) Fischer-Tropsch synthesis product.
• Fischer-Tropsch derived gas oils are described in EP-A-583836 , WO-A-9714768 , WO-A-9714769 , WO-A-0011116 , WO-A-0011117 , WO-A-0183406 , WO-A-0183648 , WO-A-0183647 , WO-A-0183641 , WO-A-0020535 , WO-A-0020534 , EP-A-1101813 and US-A-6204426 .
• the Fischer-Tropsch derived gas oil will consist of at least 90 wt%, more preferably at least 95 wt% of iso and linear paraffins.
• the weight ratio of iso-paraffins to normal paraffins will suitably be greater than 0.3. This ratio may be up to 12. Suitably this ratio is between 2 and 6.
• the actual value for this ratio will be determined, in part, by the hydroconversion process used to prepare the Fischer-Tropsch derived gas oil from the Fischer-Tropsch synthesis product. Some cyclic-paraffins may be present.
• the Fischer-Tropsch derived gas oil has essentially zero content of sulphur and nitrogen (or amounts which are no longer detectable).
• the Fischer-Tropsch derived gas oil will suitably have a distillation curve which will for its majority be within the typical gas oil range: between about 150 and 400 °C.
• the Fischer-Tropsch gas oil will suitably have a T90 wt% of between 340-400 °C, a density of between about 0.76 and 0.79 g/cm 3 at 15°C, a cetane number greater than 70, suitably between about 74 and 82, and a viscosity between about 2.5 and 4.0 centistokes at 40 °C.
• the petroleum derived gas oils are gas oils as obtained from refining and optionally (hydro)processing of a crude petroleum source.
• the petroleum derived gas oil may be a single gas oil stream as obtained in such a refinery process or be a blend of several gas oil fractions obtained in the refinery process via different processing routes. Examples of such different gas oil fractions as produced in a refinery are straight run gas oil, vacuum gas oil, gas oil as obtained in a thermal cracking process and light and heavy cycle oil as obtained in a fluid catalytic cracking unit and gas oil as obtained from a hydrocracker unit.
• a petroleum derived gas oil may comprise some petroleum derived kerosene fraction.
• the straight run gas oil fraction is the gas oil fraction, which has been obtained in the atmospheric distillation of the crude petroleum refinery feedstock. It has an Initial Boiling Point (IBP) of between 150 and 280 °C and a Final Boiling Point (FBP) of between 320 and 380 °C.
• the vacuum gas oil is the gas oil fraction as obtained in the vacuum distillation of the residue as obtained in the above referred to atmospheric distillation of the crude petroleum refinery feedstock.
• the vacuum gas oil has an IBP of between 240 and 300 °C and a FBP of between 340 and 380 °C.
• the thermal cracking process also produces a gas oil fraction, which may be used in step (a).
• This gas oil fraction has an IBP of between 180 and 280 °C and a FBP of between 320 and 380 °C.
• the light cycle oil fraction as obtained in a fluid catalytic cracking process will have an IBP of between 180 and 260 °C and a FBP of between 320 and 380 °C.
• the heavy cycle oil fraction as obtained in a fluid catalytic cracking process will have an IBP of between 240 and 280 °C and a FBP of between 340 and 380 °C.
• These feedstocks may have a sulphur content of above 0.05 wt%. The maximum sulphur content will be about 2 wt%.
• the Fischer-Tropsch derived gas oil comprises almost no sulphur it could still be necessary to lower the sulphur level of the petroleum derived gas oil in order to meet the current stringent low sulphur specifications.
• the reduction of sulphur will be performed by processing these gas oil fractions in a hydrodesulphurisation (HDS) unit.
• HDS hydrodesulphurisation
• Gas oil as obtained in a fuels hydrocracker has suitably an IBP of between 150 and 280 °C and a FBP of between 320 and 380°C.
• the cetane number of the (blend of) petroleum derived gas oil (fractions) as described above is preferably greater than 40 and less than 70.
• Other properties of the blend need to meet the required specifications. Examples of such properties are the Cloud Point, CFPP (cold filter plugging point), Flash Point, Density, Di+-aromatics content, Poly Aromatics and/or distillation temperature for 95% recovery.
• the final blended gas oil product comprising the Fischer-Tropsch and the petroleum derived gas oil will have a sulphur content of at most 2000 ppmw (parts per million by weight) sulphur, preferably no more than 500 ppmw, most preferably no more than 50 or even 10 ppmw.
• the density of such a blend is typically less than 0.86 g/cm 3 at 15 °C, and preferably less than 0.845 g/cm 3 at 15 °C.
• the lower density of such a blend as compared to conventional gas oil blends results from the relatively low density of the Fischer-Tropsch derived gas oils.
• the above fuel composition is suited as fuel in an indirect injection diesel engine or a direct injection diesel engine, for example of the rotary pump, in-line pump, unit pump, electronic unit injector or common rail type.
• the final gas oil blend may be an additised (additive-containing) oil or an unadditised (additive-free) oil. If the fuel oil is an additised oil, it will contain minor-amounts of one or more additives, e.g.
• additives selected from detergent additives, for example those obtained from Infineum (e.g., F7661 and F7685) and Octel (e.g., OMA 4130D); lubricity enhancers, for example EC 832 and PARADYNE 655 (ex Infineum), HITEC E580 (ex Ethyl Corporation), VEKTRON 6010 (ex Infineum) (PARADYNE, HITEC and VEKTRON are trademarks) and amide-based additives such as those available from the Lubrizol Chemical Company, for instance LZ 539 C; dehazers, e.g., alkoxylated phenol formaldehyde polymers such as those commercially available as NALCO EC5462A (formerly 7D07) (ex Nalco.), and TOLAD 2683 (ex Petrolite) (NALCO and TOLAD are trademarks); anti-foaming agents (e.g., the polyether-modified polysiloxanes commercially available as TEGOPREN
• the additive concentration of each such additional component in the additivated fuel composition is preferably up to 1 %w/w, more preferably in the range from 5 to 1000 ppmw, advantageously from 75 to 300 ppmw, such as from 95 to 150 ppmw.

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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)
• Combustion Methods Of Internal-Combustion Engines (AREA)

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Publications (2)

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• 2003
  • 2003-04-15 AU AU2003229676A patent/AU2003229676A1/en not_active Abandoned
  • 2003-04-15 WO PCT/EP2003/003927 patent/WO2003087273A1/en not_active Ceased
  • 2003-04-15 JP JP2003584217A patent/JP2005522569A/ja active Pending
  • 2003-04-15 DE DE60332937T patent/DE60332937D1/de not_active Expired - Lifetime
  • 2003-04-15 CN CNB038085887A patent/CN1276062C/zh not_active Expired - Fee Related
  • 2003-04-15 EP EP03722483A patent/EP1506272B1/en not_active Expired - Lifetime
  • 2003-04-15 BR BR0308905-3A patent/BR0308905A/pt not_active IP Right Cessation
  • 2003-04-15 AT AT03722483T patent/ATE470696T1/de not_active IP Right Cessation
  • 2003-04-15 US US10/511,127 patent/US20050256352A1/en not_active Abandoned

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