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
  • C10G17/00—Refining of hydrocarbon oils in the absence of hydrogen, with acids, acid-forming compounds or acid-containing liquids, e.g. acid sludge
  • C10G17/02—Refining of hydrocarbon oils in the absence of hydrogen, with acids, acid-forming compounds or acid-containing liquids, e.g. acid sludge with acids or acid-containing liquids, e.g. acid sludge
  • C10G17/04—Liquid-liquid treatment forming two immiscible phases
  • C10G17/06—Liquid-liquid treatment forming two immiscible phases using acids derived from sulfur or acid sludge 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
  • C10G67/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only
  • C10G67/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only
  • C10G67/08—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only including acid treatment as the refining step in the absence of hydrogen

Definitions

• This invention relates to desulfurization of hydrocarbon oils.
• Hydrocarbon oils such as for example those obtained by fractional distillation of petroleum, often are contaminated with sulfur containing impurities. For many purposes it is desirable that such impurities should be removed.
• desulfurization of the hydro carbon feedstock is a necessary step in the manufacture of methanol from a mixture of carbon monoxide and hydrogen produced by steam reforming of a straight-run naphtha. In this process it is essential that the naphtha should be substantially free from sulfur, because if the sulfur content of the naphtha is greater than about 5 p.p.m. the catalyst used in the steam reforming process deteriorates rapidly under normal commercial conditions.
• the sulfur content of a straightrun naphtha may be decreased from 200-1000 p.p.m. to 20100 p.p.m. by treatment with sulfuric acid.
• the degree of desulfurization depends on the amount of acid used and on the thoroughness with which the acid and the hydrocarbon are mixed.
• partial desulfurization may be achieved by hydrodesulfurization.
• the sulfur content of a straight-run naphtha of boiling range up to 165 C. may be decreased from 357 p.p.m. to -26 p.p.m.
• a similar degree of desulfurization may be achieved by passing the vapor, with or without hydrogen, over a contact material comprising zinc oxide, manganese oxide or iron oxide at 350 C. to 450 C.
• a process for desulfurization of a hydrocarbon oil which is substantially free from ethylenically or acetylenically unsaturated compounds, which process comprises three stages, of which the first stage comprises treating the hydrocarbon oil with sulfuric acid under conditions as hereinafter specified, and/ or vaporizing it and then passing the vapor thus produced over a contact material comprising zinc oxide, manganese oxide or iron oxide (preferably zinc oxide) at a temperature between 350 C. and 450 C. and at a pressure between 1 and 50 atmospheres, the second stage comprises passing the vaporized hydrocarbon, together with hydrogen, at a temperature between 350 C. and 450 C. and at a pressure between 1 and 50 atmospheres, over a hydrodesulfurization catalyst, and the third stage comprises contacting the product from the second stage with a hydrogen sullide absorbing material.
• the first stage comprises treating the hydrocarbon oil with sulfuric acid under conditions as hereinafter specified, and/ or vaporizing it and then passing the vapor thus produced over a contact material comprising zinc oxide, manga
• the first stage of the process comprises one or both of two specified desulfurization steps.
• the first stage include both of these stepsi.e. treating the hydrocarbon oil with sulfuric acid, then vaporizing it and passing the vapor thus produced over a contact material comprising zinc oxide, manganese oxide or iron oxide (preferably zinc oxide) under conditions as hereinbefore specified.
• the sulfuric acid treatment may conveniently be effected at or below room temperature.
• the temperature of the oil and acid mixture should not be allowed to rise above about 40 C.
• a convenient concentration of sulfuric acid is 90 to 98% by weight.
• the oil and acid mixture remaining after the sulfuric acid treatment stage may conveniently be separated electrostatically.
• the hydrocarbon oil is preferably washed with an aqueous alkali, for example sodium hydroxide, to remove any remaining sulfuric acid, electrostatically separated from the alkali, and finally washed with water.
• an aqueous alkali for example sodium hydroxide
• the separated acid may be recycled to the vessel in which the hydrocarbon oil and acid are mixed.
• the temperature is preferably within the range 380 C. to 400 C., and the pressure is preferably between 4 and 20 atmospheres.
• hydrodesulfurization catalysts are palladium, platinum or cobalt molybdate, supported on alumina.
• cobalt molybdate catalysts are well known and comprise the oxides of cobalt and molybdenum either as such or in combined form.
• the absorbing material preferably comprises Zinc oxide, manganese oxide or iron oxide (zinc oxide being preferred). These substances have the advantage that they will eifectively absorb hydrogen sulfide from the hot hydrocarbon vapor, which therefore does not have to be cooled first.
• the treatment with a contact material comprising zinc oxide, manganese oxide or iron oxide which may comprise at least part of the first stage of the process, and the second and third stages of the process may conveniently be effected in one operation by passing the hydrocarbon vapor, mixed with hydrogen, through a sandwich consisting of a bed of hydrodesulfurization catalyst between two beds each of which comprises zinc oxide, manganese oxide or iron oxide.
• the process of the present invention is particularly suitable for desulfurization of a straight-run naphtha, by which is meant a mixture of paraffinic, naphthenic and aromatic hydrocarbons obtained by fractional distillation of petroleum and having a boiling range of about 10 C.
• the process is not suitable for desulfurization of hydrocarbons containing substantial amounts of ethylenically or acetylenically unsaturated compounds, such as for example hydrocarbons obtained as a result of a thermal cracking process.
• the naphtha is mixed with hydrogen preferably in a 1:1 molar ratio.
• the hydrode- 'sulfurization catalyst catalyses the hydrogenation of organic sulfur compounds, such as for example thiophenes and thiophanes, to hydrogen sulfide, which is absorbed by the final bed of zincoxide or its equivalent.
• the ratio of hydrogen to hydrogen sulfide in contact with the hydrodesulfurization catalyst is very high. Consequently it is impossible for any detectable amount of organic sulfur compounds to exist in equilibrium with hydrogen and the hydrogen sulfide formed in the hydrodesulfurization reaction, and a very high degree of sulfur removed can be obtained.
• the mixture of hot desulfurized naphtha vapor and hydrogen which is produced by the preferred process of the present invention, may be mixed with steam and used as the feed in a steam reforming process for production of methanol synthesis gas.
• This of course is only one use of the invention, which finds a wide application to industrial processes where hydrocarbon oils need to be desulfurized to a high degree.
• Example 1 I A Venezuelan straight-run naphtha of specific gravity 0.746 and boiling range 103 C. to 164 C. containing 250 p.p.m. of sulfur was passed through a bed of zinc oxide at 400 C. at a liquid hourly space velocity of 0.75. The sulfur content of the product was 56 p.p.m. This partially purified material, mixed with an equimolar volume of hydrogen, was then passed through a catalyst comprising 0.3% platinum on alumina at 385 C., and then through a bed of zinc oxide in the form of 45 inch pills at 385 C. to 390 C. The liquid hourly space velocities through these beds were respectively 1.1 and 0.75. The sulfur content of the product was less than 1 p.p.m.
• Example 2 A straight-run naphtha of specific gravity 0.72 approxi- Temperatur 1 C 380 Pressur 7 lbs./in. 45 Liquid hourly space velocity over cobalt molybdate catalys 0.9 Liquid hourly space velocity over zinc oxide pills 1.2
• the sulfur content of the product after the seven days run of the experiment was 1-3 p.p.m.
• the naphtha was then vaporized, mixed with an equimolecular volume of hydrogen and preheated to 400 C. under atotal pressure of 16 atmospheres.
• the mixture of naphtha and hydrogen was then passed successively through a bed of zinc oxide pi]ls, a bed of cobalt molybdate pellets, and finally a second bed of zinc oxide pills.
• the liquid hourly space velocities through these beds were respectively 2.4, 1.0,and 2.4.
• the total sulfur content of the naphtha after this treatment was 3-5 p.p.m.
• a process for desulfurization of straight-run petroleum naphtha which is substantially free from ethylenically and acetylenicaly unsaturated compounds com- 5 prising (1) contacting said oil with sulfuric acid,
• a process for desulfurization of a straight run petroleum naphtha which is substantially free from ethylenically and acetylenically unsaturated compounds comprising treating said oil with sulfuric acid, separating the oil from the acid, (3) vaporizing the oil separated from said acid, (4) contacting the vapors together with hydrogen with a hydrodesulfurization catalyst at a temperature of between 350 C. and 450 C. and a pressure of between 1 and 50 atmospheres and then (5 contacting the resulting product, while vaporized, with a material selected from the group consisting of zinc oxide, manganese oxide and iron oxide to remove hydrogen sulfide, whereby the sulfur content of said oil is reduced to at most 5 parts per million.
• a process according to claim 1 in which the naphtha is mixed with hydrogen in a 1:1 molar ratio while in contact with a hydrodesulfurization catalyst.
• a process according to claim 2 in which sulfuric acid separated from the naphtha after treatment thereof is recycled and combined with crude hydrocarbon oil for acid treatment of the oil.
• a process for desulfurization of a straight run petroleum naphtha which is substantially free from ethylenically and acetylenically unsaturated compounds comprising (1) vaporizing said oil,
• a process for desulfurization as set forth in claim 11 in which the oil is passed through a sandwich consisting of a bed of hydrodesulfurization catalyst between two beds each of which comprises material selected from the group consisting of zinc oxide, manganese oxide and iron oxide.

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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)

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Cited By (20)

Citations (9)

• 1959
  • 1959-08-20 US US834946A patent/US3063936A/en not_active Expired - Lifetime
• 1961
  • 1961-05-03 FR FR860639A patent/FR1311143A/fr not_active Expired

Patent Citations (9)

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