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
  • C10G69/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process
• • 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
  • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
  • C10G65/14—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural parallel stages only
  • C10G65/16—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural parallel stages only including only refining steps
• • 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
• • 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
  • C10G67/04—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 solvent extraction as the refining step in the absence of hydrogen

Definitions

• the present invention relates to a process for desulfurizing catalytically cracked gasoline. More particularly, the present invention relates to a process for hydrodesulfurizing catalytically cracked gasoline containing sulfur compounds and olefin components in the presence of a catalyst.
• catalytically cracked gasoline is a stock of high-octane number gasoline containing a certain amount of olefin components.
• Catalytically cracked gasoline is a gasoline fraction obtained by catalytically cracking a heavy petroleum fraction as a stock oil, such as a vacuum gas oil or an atmospheric residual oil, and recovering and distilling the catalytically cracked products:
• Catalytically cracked gasoline is a primary blending stock of automotive gasoline.
• the stock oil for catalytic cracking has a relatively high content of sulfur compounds.
• the resulting catalytically cracked gasoline also has a high sulfur compound content.
• the resulting gasoline fraction would cause environmental pollution if used as a blending stock of automotive gasoline.
• the stock oil is usually subjected to a desulfurization process prior to catalytic cracking.
• a naphtha fraction obtained by distilling crude oil is generally subjected to catalytic reforming to at least partially aromatize the same and increase its octane number. Because a reforming catalyst is generally poisoned by sulfur compounds, the naphtha fraction should also be desulfurized prior to catalytic reforming.
• a hydrodesulfurization process has hitherto been carried out to achieve the above-noted desulfurization in the field of petroleum refining.
• a hydrodesulfurization process includes contacting a stock oil to be desulfurized with an appropriate catalyst for hydrodesulfurization in a pressurized hydrogen atmosphere at a high temperature.
• Catalysts which are typically used for hydrodesulfurization of heavy petroleum fractions such as a stock oil for catalytic cracking (e.g., a vacuum gas oil or an atmospheric residual oil) and a stock oil for thermal cracking (e.g., a vacuum residual oil), comprise a group VIII element (e.g., cobalt and nickel) and a group VI element (e.g., chromium, molybdenum and tungsten) supported on an appropriate carrier (e.g., alumina).
• group VIII element e.g., cobalt and nickel
• a group VI element e.g., chromium, molybdenum and tungsten
• the hydrodesulfurization process is usually conducted at a temperature of about 300 to about 400°C, a hydrogen partial pressure of about 30 to about 200 kg/cm 2 , and a liquid hourly space velocity (hereinafter abbreviated as LHSV) of about 0.1 to about 10 1/hr.
• LHSV liquid hourly space velocity
• Catalysts which are typically used for hydrodesulfurization of naphtha comprise a combination of a group VIII element and a group VI element (e.g., a combination of cobalt and molybdenum) supported on an appropriate carrier (e.g., alumina).
• the hydrodesulfurization process is usually carried out at a temperature of about 280 to about 350°C, a hydrogen partial pressure of about 15 to about 40 kg/cm 2 , and an LHSV of about 2 to about 8 1/hr.
• the cracked gasoline fraction following hydrodesulfurization is desirably subjected to catalytic reforming, isomerization, etc. so as to increase the octane number. That is, two processes are involved.
• the technique disclosed in the unexamined published Japanese patent application No. Hei. 6-509830 based on a PCT application is an example of such a two process system.
• An object of the present invention is to provide a process for effectively hydrodesulfurizing catalytically cracked gasoline containing sulfur compounds and olefin components while minimizing the reduction of olefin components.
• the present inventors sought to develop a hydrodesulfurization process for removing sulfur compounds to a permissible level while minimizing reduction in the content of olefin components.
• the present inventors found that various sulfur compounds contained in catalytically cracked gasoline are not equally hydrodesulfurized, and the ease or difficulty in desulfurization varies depending on the molecular structure of the sulfur compounds.
• the present inventors have discovered a process for hydrodesulfurizing catalytically cracked gasoline containing sulfur compounds and olefin components, which comprises separating the catalytically cracked gasoline into a plurality of fractions including at least one of (i) a first fraction rich in sulfur compounds that are hard to desulfurize and (ii) a second fraction rich in sulfur compounds that are easy to desulfurize, next hydrodesulfurizing at least one of the first and second fractions in the presence of a catalyst, and then mixing the hydrodesulfurized fraction(s) with the remaining fractions.
• the present invention relates to a process for desulfurizing catalytically cracked gasoline comprising separating the catalytically cracked gasoline into at least one of a fraction that has a high content of a single or a plurality of sulfur compounds that are difficult to desulfurize and a fraction that has a high content of a single or a plurality of sulfur compounds that are easy to desulfurize, subjecting at least one of the fractions to hydrodesulfurization under optimum conditions, and mixing the fractions.
• the catalytically cracked gasoline for use in the present invention is a gasoline fraction distilled at a temperature of from about 30 to about 250°C.
• the catalytically cracked gasoline is obtained by catalytically cracking a heavy petroleum fraction (e.g., a vacuum gas oil or an atmospheric residual oil) to mostly convert the heavy petroleum fraction into a broad range of petroleum fractions, and recovering and distilling the catalytically cracked products.
• the catalytically cracked gasoline is often separated into a light fraction and a heavy fraction which are used depending on the intended application as a gasoline base.
• the boiling point of the light fraction is from about 30 to about 180°C, and that of the heavy fraction is from about 80 to about 250°C.
• catalytically cracked gasoline fractions contain about 10 to about 1000 ppm of sulfur compounds, such as thiophene, alkylthiophenes, benzothiophene, alkylbenzothiophenes, thiacyclopentane, alkylthiacyclopentanes, mercaptanes and sulfides.
• Catalytically cracked gasoline which has been subjected to sweetening also contains disulfides.
• These sulfur compounds can be analyzed and quantified by a GC-AED (a gas chromatography with an atomic emission detector).
• thiophene and alkylthiophenes are compounds that are difficult to desulfurize.
• Alkylthiophenes are more difficult to desulfurize than thiophene.
• the alkylthiophenes become more difficult to desulfurize with an increase in the number of constituent alkyl groups.
• the present invention is characterized in that one or more sulfur compounds which are difficult to desulfurize are identified as such, and one or more fractions having a high concentration of sulfur compounds that are hard to desulfurize are handled separately from other fractions.
• benzothiophene, alkylbenzothiophenes, thiacyclopentane, and alkylthiacyclopentanes are examples of sulfur compounds that are easy to desulfurize.
• benzothiophene is the easiest to desulfurize.
• the alkylbenzothiophenes become more difficult to desulfurize with an increase in the number of constituent alkyl groups.
• Separating the catalytically cracked gasoline into a fraction that is rich in sulfur compounds that are hard to desulfurize and into a fraction that is rich in sulfur compounds that are easy to desulfurize may be accomplished by any of distillation, adsorption, crystallization and the like. Distilling is the most convenient of these methods.
• the boiling points of typical sulfur compounds that are easy to desulfurize are as follows. Thiacyclopentane: 121.12°C; 2-methylthiacyclopentane: 133.23°C; 3-methylthiacyclopentane: 138.64°C; 2,trans-5-dimethylthiacyclopentane: 142.00°C; 2,cis-5-dimethylthiacyclopentane: 142.28°C; 3,3-dimethylthiacyclopentane: 145.00°C; 2,3-dimethylthiacyclopentane: 148.00°C; 3-ethylthiacyclopentane: 165.00°C; benzothiophene: 219.90°C; methylbenzothiophene: 243.90°C.
• the sulfur compounds that are hard to desulfurize and some of the sulfur compounds that are easy to desulfurize have boiling points that are close together. Accordingly, it is necessary to first determine the distribution of sulfur compounds by analysis, and to then select a distillation apparatus and distillation conditions that would provide the greatest degree of separation possible. After separation, the fraction that is rich in sulfur compounds that are hard to desulfurize desirably contains sulfur compounds that are hard to desulfurize in an amount of more than 50 mol%, preferably at least 60 mol%, of the total sulfur compound content.
• the fraction that is rich in sulfur compounds that are easy to desulfurize desirably contains sulfur compounds that are easy to desulfurize in an amount of more than 50 mol%, preferably at least 60 mol%, of the total sulfur compound content.
• a multi-stage distillation apparatus is preferred to a single distillation apparatus for carrying out separation and concentration at increased efficiency.
• the method used for desulfurizing a fraction that is rich in sulfur compounds that are hard to desulfurize and a fraction that is rich in sulfur compounds that are easy to desulfurize is selected according to the intended purpose.
• rich in sulfur compounds that are hard to desulfurize might be defined as a fraction containing sulfur compounds that are hard to desulfurize in an amount of more than 50 mol%, preferably at least 60 mol%, of the total content of sulfur compounds contained in the fraction.
• the language "rich in sulfur compounds that are easy to desulfurize” might be defined as a fraction containing sulfur compounds that are easy to desulfurize in an amount of more than 50 mol%, preferably at least 60 mol%, of the total content of sulfur compounds contained in the fraction.
• sulfur content is to be reduced to a limited extent
• a fraction that is rich in sulfur compounds that are easy to desulfurize is subjected to hydrodesulfurization under mild conditions, for example, in the presence of a catalyst for hydrodesulfurization at a temperature of about 200 to about 300°C, a hydrogen partial pressure of about 5 to about 20 kg/cm 2 , and an LHSV of about 4 to about 20 1/hr.
• Hydrodesulfurization of the fraction that is rich in sulfur compounds that are easy to desulfurize can be performed while retaining the olefin components that are originally present in the fraction. More particularly, if proper reaction conditions are selected, a desulfurization rate as high as 70% or even more can be achieved while controlling hydrogenation of the olefins to 10% by volume or lower, thus minimizing a reduction in octane number.
• the reaction conditions of hydrodesulfurization are selected from a temperature range of from about 200 to about 350°C, a hydrogen partial pressure range of from about 5 to about 30 kg/cm 2 , an LHSV range of from about 1 to about 20 1/hr, and a hydrogen/oil ratio range of from about 300 to about 5000 scf/bbl.
• both a fraction that is rich in sulfur compounds that are hard to desulfurize and a fraction that is rich in sulfur compounds that are easy to desulfurize are subjected to hydrodesulfurization.
• the conditions of hydrodesulfurization are optimized for each fraction to achieve the desired high rate of desulfurization while controlling hydrogenation of olefins to minimize a reduction in octane number.
• the catalyst for use in the present invention includes those ordinarily used for hydrodesulfurization in the field of petroleum refining. That is, the catalyst generally comprises a desulfurization active metal supported on a porous inorganic oxide carrier.
• the porous inorganic oxide carrier includes alumina, silica, titania, magnesia and mixtures thereof.
• Alumina and silica-alumina are preferred.
• the desulfurization active metal includes chromium, molybdenum, tungsten, cobalt, nickel and mixtures thereof. Cobalt-molybdenum and nickel-cobalt-molybdenum are preferred. These metals can have the form of a metal, an oxide, a sulfide or a mixed form thereof on the carrier.
• the active metal can be supported on the carrier by a known method, such as impregnation or co-precipitation.
• a catalyst comprising cobalt-molybdenum or nickel-cobalt-molybdenum supported on an alumina carrier is preferred.
• the amount of the active metal supported on the oxide carrier is preferably about 1 to about 30% by weight, more preferably about 3 to about 20% by weight, in terms of the oxide of the active metal.
• the metals may be preliminarily converted to sulfides in a known manner before use in hydrogenation.
• the reaction tower for hydrogenation may be of a fixed bed type, a fluidized bed type or a boiling bed type.
• a fixed bed type reactor is preferred.
• the catalytically cracked gasoline fraction can be contacted with the catalyst in any of a parallel upward flow system, a parallel downward flow system or a countercurrent flow system.
• a catalytically cracked gasoline light fraction (about a 30 to 80°C fraction) was obtained by catalytically cracking a stock oil containing an atmospheric residual oil.
• the term "about a 30 to 80°C fraction” as used herein is a nominal designation. This fraction actually contained 11.9% by weight of a fraction having a boiling point of 30°C or lower and 3.2% by weight of a fraction having a boiling point exceeding 80°C (hereinafter referred to as an 80+°C cut) as shown in Table 1 below.
• the about a 30 to 80°C fraction had a density of 0.675 g/cm 3 at 15°C, a sulfur content of 27 ppm, an olefin content of 65% by volume, and a research method octane number of 93.8.
• a commercially available catalyst comprising an alumina carrier having supported thereon 5% by weight of CoO and 17% by weight of MoO 3 was used for hydrodesulfurization after it was preliminarily converted to a sulfide form in a usual manner.
• the above-described catalytically cracked gasoline fraction was hydrodesulfurized using a fixed bed parallel downward flow type hydrogenation reaction apparatus under relatively mild conditions, i.e., at a reaction temperature of 250°C, a partial hydrogen pressure of 10 kg/cm 2 , an LHSV of 5 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• hydrodesulfurized catalytically cracked gasoline light fraction having a sulfur content of 12 ppm, an olefin content of 44% by volume, and a research method octane number of 86.1. There was no loss of liquid components due to the treatment.
• the mixture of the 70 to 80°C cut and the 80+°C cut had a sulfur content of 145 ppm and an olefin content of 59% by volume.
• the hydrodesulfurization treatment reduced the sulfur content and the olefin content to 3 ppm and 5% by volume, respectively.
• the treated oil was added to the remaining cuts to obtain catalytically cracked gasoline having a sulfur content of 8 ppm, an olefin content of 62% by volume, and a research method octane number of 91.8. There was no loss of liquid components due to the treatment.
• Example 1 The same catalytically cracked gasoline as used in Comparative Example 1 was distilled into 7 cuts each by a difference in distillation temperature of 10°C in the same manner as in Example 1.
• the 60 to 70°C cut was hydrodesulfurized using the same apparatus and catalyst as used in Comparative Example 1 at a reaction temperature of 250°C, a hydrogen partial pressure of 5 kg/cm 2 , an LHSV of 5 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the sulfur content and the olefin content of the 60 to 70°C cut were 24 ppm and 55% by volume, respectively, while those of the hydrodesulfurized oil were 5 ppm and 41% by volume, respectively.
• the treated oil of the mixture of the 70 to 80°C cut and the 80+°C cut and the treated oil of the 60 to 70°C cut were added to the remaining cuts to obtain catalytically cracked gasoline having a sulfur content of 3 ppm, an olefin content of 57% by volume, and a research method octane number of 89.5. There was no loss of liquid components due to the treatment.
• a catalytically cracked gasoline whole fraction (about a 30 to 210°C fraction) obtained by catalytically cracking stock oil containing an atmospheric residual oil was used as a catalytically cracked gasoline.
• the term "about a 30 to 210°C fraction” as used herein is a nominal designation.
• This fraction actually contained 4.9% by weight of a fraction having a boiling point of 30°C or lower and 1.5% by weight of a fraction having a boiling point exceeding 210°C (hereinafter referred to as 210+°C cut) as shown in Table 2 below.
• the whole fraction had a density of 0.731 g/cm 3 at 15°C, a sulfur content of 92 ppm, an olefin content of 43% by volume, and a research method octane number of 92.0.
• a commercially available catalyst comprising an alumina carrier having supported thereon 3.8% by weight of CoO and 12.5% by weight of MoO 3 was used for hydrodesulfurization after it was preliminarily converted to a sulfide form in a usual manner.
• the above-described catalytically cracked gasoline was hydrodesulfurized using the same reaction apparatus as used in Comparative Example 1 under mild conditions, i.e., at a reaction temperature of 240°C, a hydrogen partial pressure of 10 kg/cm 2 , an LHSV of 7 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the same catalytically cracked gasoline whole fraction as used in Comparative Example 2 was hydrodesulfurized under more severe conditions than those employed in Comparative Example 2, i.e., at a reaction temperature of 270°C, a hydrogen partial pressure of 10 kg/cm 2 , an LHSV of 5 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the apparatus and catalyst used were the same as those used in Comparative Example 2.
• the cuts that were rich in sulfur compounds that are easy to desulfurize i.e., the 120 to 130°C cut, 130 to 140°C cut, 190 to 200°C cut, 200 to 210°C cut, and 210+°C cut were mixed together and subjected to hydrodesulfurization using the same apparatus and catalyst as used in Comparative Example 2 at a reaction temperature of 240°C, a hydrogen partial pressure of 10 kg/cm 2 , an LHSV of 7 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the mixture of the cuts rich in sulfur compounds that are easy to desulfurize had a sulfur content of 171 ppm and an olefin content of 28% by volume, which were reduced by hydrodesulfurization to 33 ppm and 26% by volume, respectively.
• the oil thus treated was added to the remaining cuts to obtain catalytically cracked gasoline having a sulfur content of 69 ppm, an olefin content of 42.5% by volume, and a research method octane number of 91.7. There was no loss of liquid components due to the treatment.
• Example 3 The same catalytically cracked gasoline as used in Comparative Example 2 was distilled to obtain 20 divided cuts each different in distillation temperature by 10°C in the same manner as in Example 3. A mixture of the cuts rich in sulfur compounds that are easy to desulfurize, i.e., the 120 to 130°C cut, 130 to 140°C cut, 190 to 200°C cut, 200 to 210°C cut, and 210+°C cut, was treated under the same conditions as in Example 3.
• the proportion of thiophene, a sulfur compound that is hard to desulfurize, of the sulfur content of the 70 to 80°C cut and the 80 to 90°C cut was 85 mol% and 90 mol%, respectively;
• the proportion of methylthiophene, a sulfur compound that is hard to desulfurize, of the 110 to 120°C cut was 87 mol%;
• the proportion of dimethylthiophene, a sulfur compound that is hard to desulfurize, of the 140 to 150°C cut was 87 mol%;
• the total proportion of trimethylthiophene, methylethylthiophene, and propylthiophene, which are sulfur compounds that are hard to desulfurize, of the sulfur content of the 160 to 170°C cut was 69 mol%;
• Those cuts rich in sulfur compounds that are hard to desulfurize i.e., the 70 to 80°C cut, 80 to 90°C cut, 110 to 120°C cut, 140 to 150°C cut, 160 to 170°C cut, and 180 to 190°C cut were mixed and hydrodesulfurized using the same apparatus and catalyst as used in Comparative Example 2 at a reaction temperature of 300°C, a hydrogen partial pressure of 30 kg/cm 2 , an LHSV of 5 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the mixture of the cuts rich in sulfur compounds that are hard to desulfurize had a sulfur content of 166 ppm and an olefin content of 31% by volume, which were reduced to 14 ppm and 4% by volume, respectively, by the hydrodesulfurization treatment.
• the treated oil was added to the remaining cuts to obtain catalytically cracked gasoline having a sulfur content of 25 ppm, an olefin content of 35% by volume, and a research method octane number of 89.2. There was no loss of liquid components by the treatment.
• a catalytically cracked gasoline whole fraction (about a 30 to 230°C fraction) was obtained by catalytically cracking a stock oil containing an atmospheric residual oil.
• the whole fraction had a density of 0.748 g/cm 3 at 15°C, a sulfur content of 352 ppm, an olefin content of 38% by volume, and a research method octane number of 91.7.
• the whole fraction was hydrodesulfurized using the same apparatus and catalyst as in Comparative Example 1 at a reaction temperature of 250°C, a hydrogen partial pressure of 10 kg/cm 2 , an LHSV of 7 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the same catalytically cracked gasoline as used in Comparative Example 4 was divided by distillation into a 30 to 100°C cut and a 100 to 230°C cut.
• the ratio of the 30 to 100°C cut to the whole fraction was 32% by weight, and the 30 to 100°C cut had a sulfur content of 62 ppm and an olefin content of 53% by volume.
• the ratio of the 100 to 230°C cut to the whole fraction was 68% by weight, and the 100 to 230°C cut had a sulfur content of 488 ppm and an olefin content of 31% by volume.
• the sulfur content of the 100 to 230°C cut was found by analysis to consist of 28 mol% of benzothiophene, 31 mol% of methylbenzothiophene, 2 mol% of thiacyclopentane, and 3 mol% of methylthiacyclopentane, which are sulfur compounds that are easy to desulfurize, and the balance of thiophene compounds which are sulfur compounds that are hard to desulfurize.
• the 100 to 230°C cut rich in sulfur compounds that are easy to desulfurize was hydrodesulfurized using the same apparatus and catalyst as used in Comparative Example 1 at a reaction temperature of 250°C, a hydrogen partial pressure of 10 kg/cm 2 , an LHSV of 5 1/hr, and a hydrogen/oil ratio of 1000 scf/bbl.
• the sulfur content and the olefin content were reduced to 135 ppm and 28% by volume, respectively.
• the treated oil was mixed with the 30 to 100°C cut to obtain catalytically cracked gasoline having a sulfur content of 112 ppm, an olefin content of 36% by volume, and a research method octane number of 90.5. There was no loss of liquid components due to the treatment.
• the catalytic hydrodesulfurization process for treating catalytically cracked gasoline containing sulfur compounds and olefin components is characterized in that the catalytically cracked gasoline is separated into a fraction rich in sulfur compounds that are hard to desulfurize and a fraction rich in sulfur compounds that are easy to desulfurize. One or both of the fractions are subjected to hydrodesulfurization under optimum conditions, and the fractions are then mixed together again.
• the process of the present invention makes it possible to efficiently desulfurize stock oil while suppressing a reduction in olefin content, to thereby minimize a reduction in octane number.

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• 1995
  • 1995-02-03 JP JP03776495A patent/JP3443474B2/ja not_active Expired - Lifetime
  • 1995-12-23 TW TW084113905A patent/TW318862B/zh not_active IP Right Cessation
• 1996
  • 1996-02-02 KR KR1019960002500A patent/KR100396143B1/ko not_active IP Right Cessation
  • 1996-02-02 CA CA002168720A patent/CA2168720C/en not_active Expired - Lifetime
  • 1996-02-03 SG SG1996000905A patent/SG52231A1/en unknown
  • 1996-02-05 DE DE69609640T patent/DE69609640T2/de not_active Expired - Lifetime
  • 1996-02-05 EP EP96101595A patent/EP0725126B1/de not_active Expired - Lifetime

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