US3725491A - Process for recovering heat from gas mixtures obtained by the thermal cracking of hydrocarbons - Google Patents

Process for recovering heat from gas mixtures obtained by the thermal cracking of hydrocarbons Download PDF

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Publication number
US3725491A
US3725491A US00115319A US3725491DA US3725491A US 3725491 A US3725491 A US 3725491A US 00115319 A US00115319 A US 00115319A US 3725491D A US3725491D A US 3725491DA US 3725491 A US3725491 A US 3725491A
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United States
Prior art keywords
oil
wash
stage
heat
cracked
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Expired - Lifetime
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US00115319A
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English (en)
Inventor
K Gunther
K Noha
H Voigt
E Schneck
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Hoechst AG
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Hoechst AG
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
    • F28C3/00—Other direct-contact heat-exchange apparatus
    • F28C3/06—Other direct-contact heat-exchange apparatus the heat-exchange media being a liquid and a gas or vapour
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D51/00—Auxiliary pretreatment of gases or vapours to be cleaned
    • B01D51/10—Conditioning the gas to be cleaned
    • 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
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G9/002—Cooling of cracked gases

Definitions

  • the present invention relates to a process for recovering heat from a gas mixture obtained by the cracking of hydrocarbons or mixtures of hydrocarbons directed to the production'of acetylene and/or lower olefins, for example, ethylene and propylene, at final cracking temperatures of up to l,500 C.
  • the result of the cracking process depends on the height of the final cracking temperature and the feedstock used.
  • asphalt-like compoundslike soot and coke are formed, which interfere with the quenching and cooling of the cracked gases, particularly if high-boiling feedstock, for example gas oil, is used.
  • the oil wash serves to free the cracked gases from these constituents before a further treatment and to cool them.
  • the wash oil is generally circulated through the washing apparatus and the said impurities are removed by drawing off a slip stream of oil.-The circulating wash oil can be kept at a desired temperature level by indirect heat exchange with a cooling agent, for example water.
  • the heat absorbed by the cooling agent can be utilized, for example, for the production of steam.
  • this known process for the recovery of heat it is generally desired to recover the heat at as high a temperature as possible, for example, in order. to produce steam of as high a working power and in as large an amount aspossible.
  • the effectiveness of this process is limited, however, by the boiling behavior of the wash oil. If the wash oil is kept at a low temperature to avoid losses by vaporization, more heat can be recovered than at higher temperatures of the wash oil but it is only possible in this case to produce steam of a correspondingly low quality.
  • higher temperatures of the wash oil part of the heat is recovered at a higher temperature, while the other part is entrained by the oil vapor developed in a larger amount and can be recovered in the following process stages only at considerably lower temperature.
  • the present invention therefore provides a process in which in a first stage of the oil wash, using temperatures within the boiling range of the wash oil and approximately atmospheric pressures, a cycle of high-boiling oil components is maintained and low-boiling oil components which are recycled from a second wash stage in the form of a condensate are exposed to a direct vaporization by the quenched cracked gases, the saturated mixture of oil vapor and cracked gas formed in the first wash stage is then fed to the second wash stage where the predominant part of the oil is condensed by indirect cooling of the mixture, thecondensing oil entraining the impurities originating from the cracking process, the heat of condensation so obtained is fed to a heater, and the cracked gases are then subjected together with the remaining vapors to a known fractionation and other separating processes.
  • the cracking reactor 1 is charged through pipe 2 with a hydrocarbon mixture and at 3 with cracking.
  • the cracking energy may be supplied, as shown in the drawing, bydirect heat exchange, for example with the help of an oxygen flame or a hydrogen plasma, or by indirect heat exchange.
  • the cracked gases leaving the reactor 1 are quenched, if desired, to a temperature below 850 C by a quenching medium injected through pipe 4.
  • the first wash stage is represented in simplified manner by washing tower 5 and the second wash stage by condenser 6.
  • the boiler 7 traced in dotted lines serves to utilize the waste heat.
  • a temperature within the boiling range of the wash oil is maintained under approximately atmospheric pressure.
  • the amount of quenching medium introduced through pipe 4 and/or the boiling range of the wash oil may be controlled, for example by introduction or removal of wash oil through pipes 14, 15 and 16.
  • Liquid wash oil is cycled from the lower part of washing tower 5 through pipe 8 via pump 9 to the upper part of the tower.
  • the cracked gas flows through the first wash stage (washing tower 5) via pipe 10 to the second wash stage (condenser 6) and finally through pipe 11 to a fractionation not shown in the drawing.
  • the cracked gas conducted in this manner carries oil vapor from the first wash stage into the second wash stage.
  • oil condensate is formed.
  • the oil condensa'te is returned through pipes 12 via pump 13 to the first wash stage and again vaporized by the cracked gases.
  • the second wash stage no further cycle of wash oil is needed because the wash oil which is condensing sufficiently wets the cooling surfaces and washes the impurities originating from the cracking process back into the first wash stage.
  • the oil residues entrained by the gas can be kept small and waste heatof different grades of effectiveness can be obtained.
  • the removed wash oil is replaced by introducing fresh oil and returning oil from other process stages through pipes 16 and/or by the oil fractions obtained in the cracking reaction.
  • EXAMPLE 1 In a thermal cracking process for the manufacture of acetylene 330 kilograms water having a temperature of 80 C were used as quenching agent for 1,000 Nrn of cracked gas having an enthalpy of 0.6 mio kcal (basis at 0 C, gaseous). By quenching to a temperature of 700 C, 1,410 Nm mixture with an enthalpy of 0.43 mio kcal were obtained. This mixture was treated by the process of the invention. The oil wash was carried out with an aromatic oil of an average molecular weight of 240 kg/kmol.
  • the second stage the major part of the oil vapor was condensed.
  • the condensate so obtained constituted the washing liquid.
  • lt washed the heat exchanging surfaces and entrained the impurities originating from the cracking process.
  • the mixture of gas and vapor leaving the second wash stage had a temperature of 200 C and contained 600 kilograms of residual oil, 0.105 mio kcal being discharged with the cracked gas plus steam and 0.06 mio kcal with the oil vapor.
  • the cracked gas enriched with heavy oil vapors had an enthalpy of 200 kcal/Nm at the outlet of the first wash stage, the predominant part of the heat of the cracked gas, i.e., 400 kcal, being contained in the gas in the form of oil vapor.
  • the heat of the cracked gas is removed by double heat exchange, that is first from the cracked gas to the liquid wash oil and second by indirect heat exchange in the oil cycle 8.
  • the predominant part of the heat of the cracked gas can only be obtained at a considerably lower temperature since the wash oil in the oil cycle must be kept at a lower-temperature to avoid vaporization.
  • the saturated steam so obtained therefore has a pressure of only about 10 atmospheres gage.
  • said first stage for use there in said step of subjecting said cracked gases to an oil having components of lower-boiling temperatures than those of said higherboiling temperature oil components.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
US00115319A 1970-02-18 1971-02-16 Process for recovering heat from gas mixtures obtained by the thermal cracking of hydrocarbons Expired - Lifetime US3725491A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2007269A DE2007269C3 (de) 1970-02-18 1970-02-18 Verfahren zur Wärmerückgewinnung aus einem bei der thermischen, auf Acetylenerzeugung gerichteten, Spaltung von Kohlenwasserstoffen entstandenen Gasgemisch

Publications (1)

Publication Number Publication Date
US3725491A true US3725491A (en) 1973-04-03

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ID=5762540

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US00115319A Expired - Lifetime US3725491A (en) 1970-02-18 1971-02-16 Process for recovering heat from gas mixtures obtained by the thermal cracking of hydrocarbons

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Country Link
US (1) US3725491A (xx)
AT (1) AT306686B (xx)
BE (1) BE763030A (xx)
BR (1) BR7101103D0 (xx)
CA (1) CA952545A (xx)
CH (1) CH558314A (xx)
CS (1) CS157096B2 (xx)
DE (1) DE2007269C3 (xx)
ES (1) ES388223A1 (xx)
FR (1) FR2081009B1 (xx)
GB (1) GB1343045A (xx)
NL (1) NL7101912A (xx)
NO (1) NO128538B (xx)
PL (1) PL76471B1 (xx)
RO (1) RO63512A (xx)
SE (1) SE359290B (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3907661A (en) * 1973-01-29 1975-09-23 Shell Oil Co Process and apparatus for quenching unstable gas
US4150716A (en) * 1975-02-07 1979-04-24 Chiyoda Chemical Eng. & Constr. Co. Ltd. Method of heat recovery from thermally decomposed high temperature hydrocarbon gas
US4233137A (en) * 1975-02-07 1980-11-11 Chiyoda Chemical Engineering & Construction Co., Ltd. Method of heat recovering from high temperature thermally cracked hydrocarbons
EP0031609A1 (en) * 1979-12-21 1981-07-08 Shell Internationale Researchmaatschappij B.V. A process for recovering heat from the effluent of a hydrocarbon pyrolysis reactor

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2464091A1 (fr) * 1979-09-04 1981-03-06 Rhone Poulenc Ind Procede de traitement physique et chimique d'un courant gazeux par une pulverisation de liquide a co-courant
WO1993012200A1 (en) * 1991-12-11 1993-06-24 Exxon Chemical Patents Inc. Method for simplifying quench and tar removal facilities in steam crackers

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB929136A (en) * 1960-09-12 1963-06-19 Toyo Koatsu Ind Inc Improvements in or relating to the production of acetylene and ethylene
US3283026A (en) * 1962-12-19 1966-11-01 Knapsack Ag Purification of crude gas obtained by thermal arc splitting of hydrocarbons
US3676519A (en) * 1970-01-02 1972-07-11 Lummus Co Quench process

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1148997B (de) * 1959-03-26 1963-05-22 Basf Ag Verfahren zur Entfernung und Verwertung des bei der Flammenspaltung von Kohlenwasserstoffen entstehenden Russes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB929136A (en) * 1960-09-12 1963-06-19 Toyo Koatsu Ind Inc Improvements in or relating to the production of acetylene and ethylene
US3236905A (en) * 1960-09-12 1966-02-22 Toyo Koatsu Ind Inc Preparing acetylene and ethylene
US3283026A (en) * 1962-12-19 1966-11-01 Knapsack Ag Purification of crude gas obtained by thermal arc splitting of hydrocarbons
US3676519A (en) * 1970-01-02 1972-07-11 Lummus Co Quench process

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3907661A (en) * 1973-01-29 1975-09-23 Shell Oil Co Process and apparatus for quenching unstable gas
US4150716A (en) * 1975-02-07 1979-04-24 Chiyoda Chemical Eng. & Constr. Co. Ltd. Method of heat recovery from thermally decomposed high temperature hydrocarbon gas
US4233137A (en) * 1975-02-07 1980-11-11 Chiyoda Chemical Engineering & Construction Co., Ltd. Method of heat recovering from high temperature thermally cracked hydrocarbons
EP0031609A1 (en) * 1979-12-21 1981-07-08 Shell Internationale Researchmaatschappij B.V. A process for recovering heat from the effluent of a hydrocarbon pyrolysis reactor

Also Published As

Publication number Publication date
CH558314A (de) 1975-01-31
DE2007269B2 (de) 1973-06-28
FR2081009B1 (xx) 1975-01-17
NL7101912A (xx) 1971-08-20
FR2081009A1 (xx) 1971-11-26
SE359290B (xx) 1973-08-27
ES388223A1 (es) 1973-05-01
CS157096B2 (xx) 1974-08-23
PL76471B1 (xx) 1975-02-28
GB1343045A (en) 1974-01-10
CA952545A (en) 1974-08-06
NO128538B (xx) 1973-12-03
AT306686B (de) 1973-04-25
RO63512A (fr) 1978-10-15
DE2007269C3 (de) 1974-02-28
BR7101103D0 (pt) 1973-03-13
DE2007269A1 (de) 1971-09-09
BE763030A (fr) 1971-07-16

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