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
  • C10G45/02—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing
  • C10G45/04—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing characterised by the catalyst used
  • C10G45/06—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing characterised by the catalyst used containing nickel or cobalt metal, or compounds thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
  • C07C7/163—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation
• • 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
  • C10G45/02—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/0201—Impregnation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• Fractions consisting of or containing aromatic hydrocarbons may be obtained from petroleum hydrocarbon feedstocks or by the destructive distillation of coal. Such fractions are frequently contaminated with sulphur in a number of combined forms, and whether the fraction is to be used as such or it to be further processed it is usually necessary to remove this sulphur. This course is particularly necessary when the fraction is to undergo catalytic conversion over a sulphur-sensitive catalyst.
• An important case where desulphurisation of an aromatic material is necessary is that in which benzene is obtained, either from a petroleum feedstock by distillation and extraction procedures, or from coal, and then is hydrogenated over a nickel-containing catalyst to give cyclohexane.
• Nickel catalysts are used because they have good activity at low temperatures and because they are cheap, but they are extremely sensitive to sulphur-containing materials, and especially to thiophenic sulphur.
• This form of combined sulphur is one which is not as easily removed by conventional hydrocatalytic desulphurisation procedures as is, for example, mercaptan-type sulphur, and since the presence of such sulphur in a hydrogenation feedstock would, in addition to deactivation of the catalyst and the effect this would have on the conversion efficiency, also adversely affect the hydrogenated material, it is clear that means must be found to remove or reduce the amount of sulphur present before the feedstock is hydrogenated or is otherwise used.
• aromatic materials may be desulphurised over a supported nickel catalyst in such a way that the catalyst has a long life and operating conditions are mild.
• the technique is particularly suitable for removal of thiophenic sulphur, but since this is the most diflicult of all types of combined sulphur to remove, it will also remove other forms of sulphur. If desired, however, and if the feedstock contains a large amount of sulphur, a preliminary catalytic hydro-desulphurisation step may be employed. Hydrogen sulphide, if present, may also be removed in known manner. Such materials, although removable by the desulphurisation technique to be disclosed, would shorten the catalyst life unnecessarily unless removed previously.
• the present technique can 3,484,367 Patented Dec. 16, 1969 ggtanomically remove up to 10 p.p.m. sulphur at up to We have found that for a supported nickel catalyst there is a threshold temperature. Above this temperature the catalyst acts as a conventional hydrogenation catalyst in the presence of hydrogen, but below it hydrogenation occurs only to a limited extent. Below the threshold temperature, however, the supported nickel material is capable of absorbing sulphur. The threshold temperature is comparatively low when the supported nickel material is fresh, but as it absorbs sulphur, and thereby becomes sulphided, the threshold temperature increases.
• the sulphur capacity of the supported nickel increases with increasing temperature, so that by progressively increasing the operating temperature so that this is just below the threshold temperature the full capacity of the supported nickel may be used.
• the absorption effect is believed to be a massive effect, i.e. it is not merely a surface phenomenon, and the limit of sulphur capacity occurs when the nickel is sulphided in depth.
• the capacity of a nickel on sepiolite material is 0.06:1 at C., 0.26:1 at 200 (1., and 0.46:1 at 250 C.
• the ultimate sulphur capacity at much higher temperatures may be as high as 1:1. In practice all hydrogenation activity is lost at an average sulphurznickel atomic ratio of about 0.1:1.
• supported nickel catalyst has been used, although the effect is not catalytic in the accepted sense of the term. A small amount of hydrogen should be present, however, because it has been found that in its absence a slow deactivation of the catalyst surface occurs. This is not due directly to the presence of sulphur, but it is thought that when ring type sulphur (i.e. thiophenic sulphur) is absorbed, ring splitting occurs with combination of the sulphur with the nickel surface, leaving an unsaturated hydrocarbon fragment. It is postulated that polymerisation of these unsaturated fragments takes place and that consequently the nickel surface becomes blocked.
• ring type sulphur i.e. thiophenic sulphur
• the invention consists in a process for the desulphurisation of an aromatic feedstock which comprises contacting the feedstock in the presence of hydrogen, with a supported nickel catalyst at a temperature and pressure at which the catalyst has desulphurisation activity, but below that at which it has substantial hydrogenation activity, and progressively increasing the temperature, and, if desired, increasing the pres sure, as the catalyst takes up sulphur, the conditions of operation being such that no substantial amount of hydrogen sulphide is produced in the process.
• aromatic feedstock includes feedstocks containing a major proportion of aromatic hydrocarbons, the remainder of the feedstock being not such as to de-activate the catalyst surface or to be substantially hydrogenated under the reaction conditions, and wholly aromatic fractions or individual aromatic hydrocarbons or mixtures of such hydrocarbons not obtainable by distillation.
• aromatic hydrocarbons includes substituted aromatic hydrocarbons in which the substituent group or nickel supported on a natural or synthetic support, such as, for example, a refractory oxide of Groups II to V of the Periodic Table, or kieselguhr, pumice, or sepiolite. Sepiolite is the preferred support. It is a commercially available clay mineral which occurs naturally, and may also be prepared synthetically.
• catalysts comprising nickel supported on a base consisting essentially of sepiolite, and high surface area (and hence high activity) and high selectivity materials prepared and activated according to the disclosures of this patent are the preferred catalysts for use in the present process.
• Preferred catalysts contain from 1 to 50% nickel (expressed as elemental nickel), and more particularly from 5 to 25% wt.
• the hydrogen used in the present process may be commercially pure, or it may be used as a mixture with one or more substantially sulphur-free reaction-inert constituents.
• a suitable mixed gas would be that obtained from a steam reformer, containing 95% hydrogen, the remainder of the gas being methane. Gases containing hydrocarbons having two or more carbons per molecule may be used, provided that reaction conditions are carefully controlled to avoid cracking, which in the presence of the nickel catalyst might lead to an exothermic reaction and a temperature runaway.
• the hydrogen content of the mixed gas should be at least 50 mole percent and more particularly from 70 to 99 mole percent.
• Suitable operating conditions for the desulphurisation of an aromatic feedstock according to the invention may be selected from the following:
• the preferred range is 75 to 250 C. (167 to 482 F.) corresponding to a sulphurznickel atomic ratio of 00.51: 1 to 0.46:1.
• Pressure p.s.i.g.-- to 2000, preferably 0 to 50 up to a sulphurznickel atomic ratio of 0.1:1, and then 502000.
• Inlet hydrogen hydrocarbon ratio on total feed, molar- 0.01 to :1 (preferably 0.05 to 0.2:1).
• the reaction pressure may be increased stepwise, since it has been found that this increases the extent of desulphurisation at a given temperature. However, it also increases the extent of hydrogenation taking place at that temperature, and therefore lowers the threshold temperature.
• the process is carried out, when using a fresh catalyst, by passing the feedstock over the catalyst at a temperature and pressure close to the lower limits of the ranges given above, at which it is known that hydrogenation will not occur to an extent sufficient to cause an unacceptable temperature rise.
• the sulphur content of the effluent from the process, and its naphthene content are surveyed and when the sulphur content increases to above a set level the temperature, and, if desired, the pressure, are increased to such an extent that the set value is attained. If the naphthene content increases above the desired level, the temperature and, optionally, pressure, need to be reduced.
• the actual values of temperature and pressure are, accordingly compromise values.
• the desulphurised product of the present process may be hydrogenated over a suitable catalyst, such as a nickel or platinum hydrogenation catalyst.
• a suitable catalyst such as a nickel or platinum hydrogenation catalyst.
• a process for the hydrogenation of benzene containing less than 1 p.p.m. sulphur to cyclohexane using two hydrogenation stages is disclosed in British patent application No. 28,767/65.
• the present desulphurisation process may be used to obtain benzene having less than the above amount of sulphur, and the hydrogenation process of this copending application preferably uses nickel on sepiolite as the catalyst in each stage.
• the invention is illustrated by the following example.
• Cyclohexane Sulphur content of content of Catalyst, Temperature, product, product, sulphur-nickel F percent wt. p.p.m. wt. ratio, atomic At this point the plant pressure was raised to 15 p.s.i.g. and the levels of hydrogenation and desulphurisation also increased.
• 0 has desulphurisation activity but less than 5% by weight of the feed is hydrogenated and no substantial amount of hydrogen sulphide is produced, and progressively increasing the temperature within the said range as the catalyst takes up sulphur.
• reaction temperature is increased within the range 75 to 250 C.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Analytical Chemistry (AREA)
• Water Supply & Treatment (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)

Applications Claiming Priority (1)

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Cited By (1)

Citations (3)

• 1965
  • 1965-07-07 GB GB28768/65A patent/GB1144496A/en not_active Expired
• 1966
  • 1966-06-30 IL IL26071A patent/IL26071A/xx unknown
  • 1966-07-01 US US562124A patent/US3484367A/en not_active Expired - Lifetime
  • 1966-07-04 NO NO163775A patent/NO120150B/no unknown
  • 1966-07-06 DE DE19661568139 patent/DE1568139A1/de active Pending
  • 1966-07-06 ES ES0329183A patent/ES329183A1/es not_active Expired
  • 1966-07-07 AT AT650866A patent/AT283309B/de not_active IP Right Cessation
  • 1966-07-07 SE SE09306/66A patent/SE333789B/xx unknown
  • 1966-07-07 NL NL6609522A patent/NL6609522A/xx unknown
  • 1966-07-07 BE BE683782D patent/BE683782A/xx unknown
  • 1966-07-07 CH CH988866A patent/CH492665A/de not_active IP Right Cessation

Patent Citations (3)

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