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
  • C10G70/00—Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00
  • C10G70/04—Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00 by physical processes
  • C10G70/06—Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00 by physical processes by gas-liquid contact
• • 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
  • C10G70/00—Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00
  • C10G70/04—Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00 by physical processes
  • C10G70/041—Working-up undefined normally gaseous mixtures obtained by processes covered by groups C10G9/00, C10G11/00, C10G15/00, C10G47/00, C10G51/00 by physical processes by distillation
• • 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
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/10—Feedstock materials
  • C10G2300/1037—Hydrocarbon fractions
  • C10G2300/1044—Heavy gasoline or naphtha having a boiling range of about 100 - 180 °C
• • 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
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/20—Characteristics of the feedstock or the products
  • C10G2300/201—Impurities
  • C10G2300/207—Acid gases, e.g. H2S, COS, SO2, HCN

Definitions

• This invention relates generally to fractionation columns, and more particularly, to apparatus and methods for removing H 2 S and moisture from the naphtha overhead of a fractionator.
• Hydrocarbon feeds can be reacted in a hydroprocessing zone where a number of reactions take place, including hydrocracking, hydrotreating, hydrogenation, and
• the hydroprocessing zone is typically followed by a stripper column, where the hydroprocessing zone effluent is separated into a stripper overhead stream and a stripper bottoms stream.
• the stripper column bottoms is sent to a fractionation column, where it is separated into a fractionation column bottoms stream and a naphtha overhead stream.
• Other streams such as light gas oil and heavy gas oil streams, can also be separated out in the fractionator, if desired.
• the naphtha overhead stream is recovered.
• the naphtha overhead stream includes naphtha, H 2 S, and, in some cases, water.
• H 2 S generated during desulfurization reactions in the hydroprocessing zone is removed predominantly in the stripper column.
• the stripper column is designed to remove H 2 S to the level of parts per billion (ppb) in the stripper bottoms stream, small amounts of H 2 S slip through into the fractionator.
• the H 2 S becomes concentrated to a level of parts per million (ppm) in the fractionator overhead liquid stream.
• ASTM D-4952-09 Doctor Test
• wppm An H 2 S level of 1 weight ppm (wppm) can result in the naphtha not meeting the Doctor Test.
• the H 2 S must be removed from the naphtha overhead stream using a secondary processing system.
• the H 2 S is removed using a caustic (NaOH) wash and a sand filter.
• Caustic NaOH
• refiners do not want to use caustic because of the hazards associated with handling it and problems related to disposing of the spent caustic.
• the naphtha may be sent to a downstream stabilizer/sp litter combination for removal of light petroleum gas.
• the H 2 S can be removed along with the light petroleum gas.
• this equipment increases the cost of the process.
• One aspect of the present invention relates to a method of making naphtha substantially free of H 2 S.
• the method includes stripping an incoming stream containing naphtha and H 2 S in a fractionator into at least an overhead stream containing the naphtha and H 2 S and a bottoms stream, and introducing the overhead stream from the fractionator into a separator to form a naphtha stream substantially free of H 2 S and an overhead stream containing H 2 S.
• the apparatus includes a hydroprocessing zone having an inlet and an outlet.
• the inlet of a stripper column is in fluid communication with the outlet of the
• the inlet of the stripping fractionator is in fluid communication with the bottoms outlet of the stripper column.
• the apparatus includes a separator having an inlet, a product outlet, and an overhead outlet. The inlet of the separator is in fluid communication with the overhead outlet of the stripping fractionator.
• FIG. 1 illustrates one embodiment of a process utilizing the present invention.
• FIG. 2 illustrates another embodiment of a process utilizing the present invention.
• a separator including but not limited to, vacuum dryers or coalescers
• the H 2 S can be removed, and the naphtha can be made substantially free of H 2 S.
• naphtha we mean C5 hydrocarbons up to hydrocarbons having a boiling point of 150°C (i.e., hydrocarbons having a boiling point in the range of 30°C to 150°C).
• substantially free of H 2 S we mean the H 2 S content is undetectable by ASTM test method UOP 163 and the naphtha passes the Doctor Test, ASTM D4952. This eliminates the need for the caustic/sand filter arrangement or the downstream stripper/stabilizer.
• the separator is a vacuum dryer
• the liquid portion of the vacuum dryer overhead can be recycled back to the stripper.
• the separator can be a coalescer which is installed to remove the water, and hence the H 2 S.
• Fig. 1 illustrates one embodiment of a process utilizing the present invention.
• the feed 5 can be any hydrocarbon feed stream(s) predominantly boiling between 240°C and 600°C.
• the feed 5 is hydroprocessed in the hydroprocessing zone 10.
• the effluent 15 can be subjected to one or more separation processes where at least a portion of the gas is removed and the remaining liquid/gas effluent proceeds, as is known in the art (not shown), if desired.
• the remaining effluent 15 from the hydroprocessing zone 10 is sent to a stripper column 20, where it is separated into a stripper overhead stream 25 containing at least one of light naphtha, light petroleum gas, light hydrocarbons, and H 2 S, and a stripper bottoms stream 30 containing light and heavy naphtha, other hydrocarbons heavier than naphtha (e.g., kerosene, diesel, vapor gas oil, unconverted oil, and the like, depending on the feed and the
• the stripper bottoms stream 30 is sent to a fractionator 35. Stripping medium 40 is introduced into the fractionator 35.
• the stripper bottoms stream 30 is separated into a fractionator bottoms stream 45 containing unconverted oil, a heavy gas oil (HGO) stream 50, a light gas oil (LGO) stream 55, and a fractionator overhead stream 60.
• HGO heavy gas oil
• LGO light gas oil
• the HGO stream 50 and LGO stream 55 can be further processed and/or recovered, if desired.
• the fractionator overhead stream 60 contains primarily naphtha, and H 2 S.
• Fractionator overhead stream 60 is sent to receiver 65 wherein it is separated into a receiver overhead gas stream 70, a sour water stream 75, and a liquid naphtha stream 80.
• the liquid naphtha stream 80 can contain small amounts of water and H 2 S.
• the liquid naphtha stream 80 is split into a reflux stream 85, which is sent back to the fractionator column 35, and stream 90, which is sent to a separator.
• Suitable separators include, but are not limited to, a vacuum dryer 95, as shown in Fig. 1, or a coalescer 130, as shown in Fig. 2.
• Sufficient H 2 S is removed in the vacuum dryer 95 so that the naphtha in product stream 100 is substantially free of H 2 S.
• An overhead stream 105 from the vacuum dryer 95 contains H 2 S.
• the vacuum dryer is operated under vacuum.
• the level of vacuum is not limited; however, it is desirably the lowest level that will remove sufficient H 2 S so that the naphtha in product stream 100 is substantially free of H 2 S.
• the vacuum dryer can be operated at any suitable temperature. The temperature of operation is related to the level of vacuum generated in the dryer (i.e., the higher the level of vacuum, the lower the temperature needs to be).
• the vacuum dryer overhead stream 105 is sent to an ejector receiver 110, where it is separated into ejector stream 115, which is condensed steam, a non-condensible vapor stream 120, and a condensable stream 125.
• ejector stream 115, non-condensible vapor stream 120, and condensable stream 125 will have some H 2 S in them.
• Condensable stream 125 can be recycled to the stripper column 20, if desired.
• a coalescer 130 could be used, as illustrated in Fig. 2.
• the coalescer 130 removes the water as stream 135 from the naphtha product 140. Because of the high solubility of H 2 S in water, the H 2 S would be removed with the water.
• Typical operating conditions for the coalescer include operating at the temperature of stream 90.

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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)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (5)

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• 2012
  • 2012-08-17 US US13/588,065 patent/US9181501B2/en active Active
• 2013
  • 2013-07-25 WO PCT/US2013/051955 patent/WO2014028190A1/en not_active Ceased
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