EP0237661A1 - Procédé de conversion d'hydrocarbures - Google Patents

Procédé de conversion d'hydrocarbures Download PDF

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Publication number
EP0237661A1
EP0237661A1 EP86301965A EP86301965A EP0237661A1 EP 0237661 A1 EP0237661 A1 EP 0237661A1 EP 86301965 A EP86301965 A EP 86301965A EP 86301965 A EP86301965 A EP 86301965A EP 0237661 A1 EP0237661 A1 EP 0237661A1
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EP
European Patent Office
Prior art keywords
stream
conversion
fractionation tower
tower
hydrocarbon
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86301965A
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German (de)
English (en)
Inventor
Martin Anthony Murphy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ExxonMobil Technology and Engineering Co
Original Assignee
Exxon Research and Engineering Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB08424077A priority Critical patent/GB2164659B/en
Application filed by Exxon Research and Engineering Co filed Critical Exxon Research and Engineering Co
Priority to EP86301965A priority patent/EP0237661A1/fr
Publication of EP0237661A1 publication Critical patent/EP0237661A1/fr
Withdrawn legal-status Critical Current

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    • 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
    • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • 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
    • C10G7/00—Distillation of hydrocarbon oils

Definitions

  • the present invention relates to a hydrocarbon conversion process.
  • the hydrocarbon chargestock for such conversion processes has been separated by distillation into a fraction which is suitable for conversion and other fractions, among which are fractions of low utility, such as fuel oil.
  • the converted fraction is substantially at the elevated conversion temperature and is passed to a fractionation tower in which separation into heavy and light conversion products occurs and is promoted.
  • the heavier fractionated materials are withdrawn from the bottom of the fractionation tower, and a portion thereof is cooled and circulated back to the top of a lower zone of the fractionation tower where it serves to desuperheat and quench converted products entering the fractionation tower. It will be appreciated that the amount of heat which must be removed from the recirculated heavier fractionated materials to provide adequate desuperheating and quenching of the converted products is relatively great, and this is reflected in a correspondingly great investment in suitable cooling equipment.
  • the hydrocarbon chargestock is crude oil which is separated by distillation in an atmospheric pipestill into a plurality of fractions including a reduced crude boiling at 700°F+ (371°C).
  • the reduced crude is passed to a conversion products fractionation tower which it enters at the top of the stripping section so as to quench and be stripped by hot effluent from a catalytic cracker so that a bottoms products is recovered from the bottom of the fractionation tower at a temperature of 820 to 830°F (438 to 443°C).
  • the feed for the catalytic cracker is either wholly or mainly a gas oil fraction which is withdrawn from the fractionation tower at a location above the top of the stripping section. Some of the bottoms product is cooled to 700°F (371°C) and recirculated to the bottom of the tower to avoid cracking and the deposition of coke, and the remainder (amounting to 12 to 18% of the original feed) is discarded as a low value oil component.
  • the present invention provides a hydrocarbon conversion process comprising the steps of :
  • the distillation unit comprises an atmospheric pressure distillation zone wherein an atmospheric residue is separated from the hydrocarbon chargestock under approximately atmospheric pressure, and a vacuum distillation zone operating under sub-atmospheric pressure which receives at least some atmospheric residue from the atmospheric pressure distillation zone and separates it into a plurality of discrete streams of which one is said vacuum residue stream and another is the said conversion feed stream.
  • the temperature and/or pressure within the vacuum distillation zone and/or the fractionation tower is and/or are adjusted so that the vapour pressure of liquid leaving the lowest fractionation device of the vacuum distillation zone is higher than the vapour pressure of liquid leaving the lower fractionation device of the fractionation tower.
  • the hydrocarbon conversion unit may be a catalytic cracking unit (e.g. a fluid catalytic cracking unit, FCCU).
  • FCCU fluid catalytic cracking unit
  • the invention also provides apparatus for performing the new process as described above.
  • Crude oil is supplied via line 11 to an atmospheric pipestill (“APS") 12 wherein it is separated into a plurality of streams including an atmospheric residuum stream which is recovered from the bottom of APS 12 via line 13 and passed via a heating device, which in this instance, is a furnace 14, and line 15 to a vacuum pipestill (“VPS”) 16 operated under subatmospheric pressure.
  • APS atmospheric pipestill
  • VPS vacuum pipestill
  • the atmospheric residuum is separated into a plurality of streams including a gas oil stream, a vacuum residuum stream, and other streams.
  • the vacuum residuum stream is removed from the bottom of the VPS 16 via line 17 and pump 18, and is thereafter cooled in heat exchanger 19 and then passed via line 20 to a receiving tank 21 wherein low utility, low value products are received for use as fuel oil blending components or as feed for other refining and/or conversion operations.
  • the gas oil stream is passed from the VPS 16 via line 22 to a heating device, which in this instance, is a furnace 23, and thereafter via line 24 to a catalytic cracking unit 25 (enclosed within the broken lines) wherein the gas oil stream is converted in the reactor at an elevated temperature to catalytically cracked products.
  • the latter are recovered via line 26 and passed at substantially the elevated temperature of the reactor into a lower part of the lower region 27 of a fractionating column 28.
  • the lower region 27 operates as a desuperheating zone.
  • the cracked products are separated into a plurality of fractionation streams including normally gaseous streams (e.g. H2, CH4, C2H6, liquid petroleum gas fractions), normally liquid streams (e.g. light and heavy naphthas, kerosines), and higher boiling streams including a so-called cycle gas oil stream ("CGO stream”) and a cracked residue.
  • normally gaseous and liquid streams are recovered from the fractionating column 28 via respective conduits (not shown) and reference will hereinafter be made only to the cycle gas oil and cracked residue streams.
  • the CGO stream is recovered from the fractionating column 28 via line 29 and circulated to the cracking unit 25, in admixture with the gas oil stream in line 22, for further conversion in the cracking unit 25.
  • the cracked residue is recovered from the bottom of the fractionating column 28 via line 30 under the action of pump 31.
  • a major proportion of the cracked residue is passed via line 32 to heat exchanger 33 where it is cooled to a temperature approximating that at the top of the lower, desuperheating region 27.
  • a major portion of the resulting cooled cracked residue is circulated via line 34 to the top of the desuperheating region 27 where it enters the fractionating column 28 and passes downwards in countercurrent to vapour phase cracked products rising up the desuperheating region 27 whereby some vapour phase cracked products are condensed and separation of the cracked products into different boiling fractions occurs.
  • the remaining cooled cracked residue is passed via line 35 into the base region of the fractionating column 28 to provide additional local cooling and thereby prevent continued cracking and the formation and deposition of coke in the base region of the column 28.
  • the temperature and rate of supply of cooled cracked residue to the desuperheating region 27 is at least sufficient to prevent cracking and concomitant coke deposition on the vapour-liquid contacting elements (for example, those known in the art as "sheds") 37 within the desuperheating region 27.
  • the portion of the cracked residue which is not passed via line 32 to the heat exchanger 33 is discarded via line 38 as a low value fuel oil component which is discharged into receiving tank 21 after it has been cooled to a suitable temperature (e.g.250°F, 121°C) for receipt and storage in the tank 21.
  • the cooling is effected by a heat ex­changer 60 in line 38.
  • the VPS residuum stream is cooled in heat exchanger 19 and then discarded via line 20 as, e.g. a fuel oil component
  • the VPS residuum e.g. after cooling in the heat exchanger 19 is not discharged to the receiving tank 21 but is employed as at least part of the desuperheating and quenching medium in the fractionating column 28.
  • the VPS residuum after suitable cooling, is passed via line 50 into the top of the lower region 27 of the fractionating column 28.
  • the cooling of the VPS residuum in Figure 2 may be effected wholly in heat exchanger 19 or partly in heat exchanger 19 and partly in heat exchanger 33 or wholly in heat exchanger 33 (in which case, heat exchanger 19 may be eliminated from the Figure 2 embodiment).
  • the contact between the rising hot cracked products entering column 28 and the descending cooled VPS residuum not only causes desuperheating and quenching of the former but additionally heating of the VPS residuum with attendant separation of the latter into vapourised fractions which rise up the interior of the column 28 and at least partly contribute to the gas oil recycle stream in line 29, and non-vapourized fractions thereof which descend to the base of the column where they are recovered via line 30 in admixture with cracked residue.
  • mixed residue The resulting mixture of fractionated VPS residuum and cracked residue, hereinafter termed “mixed residue”, is circulated by pump 31 in part to heat exchanger 33 wherein it is cooled before being passed via lines 34 and 35 to the bottom region of the lower zone 27 in order to reduce temperatures therein and thereby reduce cracking and coke deposition.
  • the remaining part of the mixed residue is conveyed by line 38 to receiving tank 21 for use as a fuel oil component and/or as a feed for use in a further conversion operation such as visbreaking, coking and/or flexicoking.
  • VPS residuum would be highly undesirable within the desuperheating lower region 27 of the fractionating tower because it would crack and cause coke deposition and, moreover, act to reduce the amount of higher utility materials available in the streams recovered from the rectifying zone (above the level of the lower region 27) of the fractionating column 28 by absorbing some of said higher utility materials. It has been discovered that, contrary to this long-held expectation, no such drawback occurs.
  • a highly preferred feature in the practice of the invention is that the vapour pressure of fluid leaving the lowest fractionating device (e.g. tray, packing element) of the VPS 16 should be higher than the vapour pressure of fluid leaving the lowest fractionating device of the fractionating column 28.
  • the manner in which this preferred feature can be realized will be well-known to those skilled in petroleum refining technology. In principle, it may be realized by arranging that (a) the pressure at the bottom of the VPS 16 is greater than that at the bottom of the fractionating column 28 or (b) the temperature at the bottom of the fractionating column 28 is greater than that at the bottom of the VPS 16, or (c) a suitable combination of (a) and (b). Those skilled in the art will know how to achieve effects (a) and/or (b).
  • the amount of cracking and coke deposition in the bottom of the fractionating column 28 is about the same or less in the Figure 2 plant compared with the Figure 1 plant.

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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)
EP86301965A 1984-09-24 1986-03-18 Procédé de conversion d'hydrocarbures Withdrawn EP0237661A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB08424077A GB2164659B (en) 1984-09-24 1984-09-24 Hydrocarbon conversion process
EP86301965A EP0237661A1 (fr) 1984-09-24 1986-03-18 Procédé de conversion d'hydrocarbures

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB08424077A GB2164659B (en) 1984-09-24 1984-09-24 Hydrocarbon conversion process
EP86301965A EP0237661A1 (fr) 1984-09-24 1986-03-18 Procédé de conversion d'hydrocarbures

Publications (1)

Publication Number Publication Date
EP0237661A1 true EP0237661A1 (fr) 1987-09-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP86301965A Withdrawn EP0237661A1 (fr) 1984-09-24 1986-03-18 Procédé de conversion d'hydrocarbures

Country Status (2)

Country Link
EP (1) EP0237661A1 (fr)
GB (1) GB2164659B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1204718A1 (fr) * 1999-06-11 2002-05-15 ExxonMobil Research and Engineering Company Attenuation de l'encrassement par des huiles de craquage thermique
CN114949906A (zh) * 2022-06-20 2022-08-30 中国海洋石油集团有限公司 一种降低分馏塔塔底物料循环量的dcc装置及方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB719003A (en) * 1950-04-01 1954-11-24 Standard Oil Dev Co Petroleum oil refining process
GB762091A (en) * 1952-08-01 1956-11-21 Exxon Research Engineering Co Improvements in or relating to combination distillation and hydrocarbon conversion process
GB773524A (en) * 1952-11-08 1957-04-24 Exxon Research Engineering Co A combined process for distilling and cracking petroleum oils
US2834715A (en) * 1954-06-03 1958-05-13 Thomas W Pratt Preparation of catalytic cracking feed

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB719003A (en) * 1950-04-01 1954-11-24 Standard Oil Dev Co Petroleum oil refining process
GB762091A (en) * 1952-08-01 1956-11-21 Exxon Research Engineering Co Improvements in or relating to combination distillation and hydrocarbon conversion process
GB773524A (en) * 1952-11-08 1957-04-24 Exxon Research Engineering Co A combined process for distilling and cracking petroleum oils
US2834715A (en) * 1954-06-03 1958-05-13 Thomas W Pratt Preparation of catalytic cracking feed

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1204718A1 (fr) * 1999-06-11 2002-05-15 ExxonMobil Research and Engineering Company Attenuation de l'encrassement par des huiles de craquage thermique
EP1204718A4 (fr) * 1999-06-11 2003-09-24 Exxonmobil Res & Eng Co Attenuation de l'encrassement par des huiles de craquage thermique
CN114949906A (zh) * 2022-06-20 2022-08-30 中国海洋石油集团有限公司 一种降低分馏塔塔底物料循环量的dcc装置及方法

Also Published As

Publication number Publication date
GB2164659A (en) 1986-03-26
GB8424077D0 (en) 1984-10-31
GB2164659B (en) 1988-06-02

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Inventor name: MURPHY, MARTIN ANTHONY