US3686344A - Production of acetylene - Google Patents

Production of acetylene Download PDF

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Publication number
US3686344A
US3686344A US47964A US3686344DA US3686344A US 3686344 A US3686344 A US 3686344A US 47964 A US47964 A US 47964A US 3686344D A US3686344D A US 3686344DA US 3686344 A US3686344 A US 3686344A
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Prior art keywords
acetylene
methanol
hydrocarbons
water
crude
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Expired - Lifetime
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US47964A
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English (en)
Inventor
Erwin Brunner
Rolf Platz
Kurt Taglieber
Kurt Weinfurter
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BASF SE
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BASF SE
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C11/00—Aliphatic unsaturated hydrocarbons
    • C07C11/22—Aliphatic unsaturated hydrocarbons containing carbon-to-carbon triple bonds
    • C07C11/24—Acetylene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/005—Processes comprising at least two steps in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/11—Purification; Separation; Use of additives by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids

Definitions

  • ABSTRACT Production of pure acetylene from a cracked gas obtained by cracking gaseous hydrocarbons, the process comprising a number of steps wherein the higher C to C hydrocarbons remaining in the crude acetylene are washed out with an organic solvent such as toluene.
  • This invention relates to a process for the production of acetylene by thermal cracking of methane, in particular natural gas, and working up the cracked gas by removing CO and washing the acetylene with a selective solvent, whereupon the crude acetylene thus obtained is further purified by a combined condensation and washing step.
  • thermal cracking of hydrocarbons immediately followed by quenching of the cracked gas gives a gas mixture consisting of hydrogen, carbon monoxide, carbon dioxide, methane, ethylene, acetylene and hydrocarbons of more than two carbon atoms.
  • Thermal cracking processes for the production of such acetylene-containing gas mixtures are described, for example, in Chemie-Ing-Techn, 26, No. 5, 253 (1954), British Pat. Specification No. 834,419 1960) and German Pat. Specification No. 1,063,595.
  • This object is achieved by conventional cracking of natural gas, washing the thus obtained cracked gas with a solvent showeing selectivity for acetylene and subsequently purifying the resulting crude acetylene in a further washing stage, in which, however, the inorganic reagents and absorbents used as washing liquors in known processes are replaced by certain organic solvents.
  • the crude acetylene to be purified in step (c) contains moisture, care must be taken to avoid the deposition of ice when the crude acetylene is chilled to l0 to 30 C, since this would eventually choke the condensing apparatus.
  • this may be simply achieved by loading the water-containing crude acetylene with methanol vapor such that a liquid mixture consisting of higher hydrocarbons, methanol and water is condensed out in the condensation step, separating the condensate in a separating vessel into a hydrocarbon phase and a methanol/water phase containing traces of hydrocarbons and acetylene, separating the latter phase in a distillation column into water as bottoms and methanol as overhead product, and recycling the desorbed acetylene together with non-condensed methanol vapor to the condensation stage.
  • the moisture-containing crude acetylene recovered from the N-methyl pyrrolidone wash may be washed, not with methanol but with anhydrous N-methyl pyrrolidone. This is particularly advantageous because no additional washing liquor need be introduced between the selective wash and the toluene wash.
  • the novel method of producing pure acetylene is carried out by thermally cracking natural gas by the aforementioned process described in Chemie-lng.-Techn. .loc. cit., to produce a cracked gas containing the following components, in percentages by volume:
  • the acetylene is washed out of the cracked gas in known manner with a suitable solvent, such as dimethyl forrnamide, butyro lactone, tetraethyl glycol dimethyl ether and, preferably, N-methyl pyrrolidone.
  • a suitable solvent such as dimethyl forrnamide, butyro lactone, tetraethyl glycol dimethyl ether and, preferably, N-methyl pyrrolidone.
  • This wash is described in detail in Chernie-Ing.-Techn., loc. cit.
  • the N-methyl pyrrolidone wash is expediently carried out by initially treating the cracked gas in a pre-washing stage using N-methyl pyrrolidone as washing liquor in order to remove the highly soluble diacetylene.
  • the acetylene is washed out in the washing column proper. Pressures between 5 and 20 atmospheres absolute, preferably between 10 and 15 atmospheres absolute, and temperatures ranging from 10 to 50 C are used. More sparingly soluble components which are also dissolved in the cracked gas stream are stripped in a countercurrent column by rising acetylene, using a column pressure preferably 1 to 2' atmospheres absolute.
  • the solvent is then regenerated in a vacuum column at pressures between 0.15 and 0.3 atmospheres absolute, in which the bottoms temperature is from to 140 C and preferably from 1 10 to C.
  • the first heat exchanger of such a combination is advantageously a packed, waterirrigated direct cooler 2, which also acts as a decomposition barrier for the acetylene. 1n the second heat exchanger 3 of the combination the gas iscooled countercurrently with condensate and pure acetylene, whilst the residual heat is removed in the third heat exchanger 4 by refrigerants.
  • the crude acetylene normally contains water vapor, and to avoid choking the condenser it is necessary to prevent the water vapor from freezing out before the crude acetylene enters the final heat exchanger, in which cooling to below 0C is effected. This may be achieved by washing the crude acetylene with methanol or anhydrous N-methyl pyrrolidone before it enters the condenser, as may be effected, for example, in a small washer attached to direct cooler 2.
  • Suitable washing liquors are, preferably, weakly polar organic liquids which are inert under the reaction conditions, have a boiling range above 80 C and a freezing point below 40 C, and low viscosity in the temperature range 20 to 40 C.
  • organic liquids are, for example, aliphatic or aromatic hydrocarbons free from functional groups. Specific examples are n-heptane, noctane, m-xylene, di-n-butyl ether and preferably toluene. Mixtures of such compounds are also eminently suitable.
  • the wash with the organic liquid boiling above 80 C is carried out in conventional apparatus, for example a washing column,.the crude acetylene entering at the bottom, whilst the organic liquid trickles down countercurrently.
  • the dimensions of this washing column are such that as many hydrocarbons as possible are washed out.
  • the heat of solution which is liberated during the countercurrent wash is conveniently removed in intermediate coolers 7,8.
  • a purified acetylene which contains, apart from C0 (0.02 percent by volume) and indifferent gases (particularly nitrogen and noble gases) (0.06 percent by volume), only 0.001 percent by volume of C to C hydrocarbons and 0.1 percent by volume of the organic washing liquor.
  • the laden organic liquor leaving the washing column as bottoms is heated to approximately 0 to C and degasified to recover dissolved acetylene, conveniently in a countercurrent tower 9.
  • the gas obtained contains about mole percent of acetylene and is recycled to the crude acetylene entering heat exchanger 2.
  • the washings leaving the countercurrent tower are then heated to about C in a heat exchanger 10 and then passed to a fractionating column 11.
  • the overhead product consists essentially of C to C hydrocarbons and contains about 0.4 mole percent of acetylene.
  • the regenerated organic washing liquor is cooled in conventional heat exchangers 12 and recycled to the washing column.
  • the methanol entrained as vapor from apparatus 2 is preferably recovered.
  • water is added to the condensate obtained by cooling the crude acetylene in the separator, and separated in a separating vessel 13 into a water/methanol phase and a hydrocarbon phase.
  • Liberated acetylene is recycled via a degasifying pipe to the second heat exchanger of the cooler combination.
  • Methanol is isolated from the methanol/water phase, conveniently by distillation in a column 14, and is reused in the condensation stage. Liberated acetylene and a portion of non-condensed methanol vapor are also recycled to the crude acetylene stream.
  • the N-methyl pyrrolidone/water mixture obtained in separating vessel 13 is passed to the countercurrent tower used for the N-methyl pyrrolidone wash. This part of the wash is not shown in F IG. 1.
  • the process according to the invention is particularly suited for the production of pure acetylene from cracked gases as obtained by cracking gaseous hydrocarbons such as natural gas.
  • a process for the production of pure acetylene which comprises the following steps:
  • step (a) thermally cracking a gaseous hydrocarbon in the presence of oxygen with subsequent quenching under conditions conducivee to the formation of acetylene; washing the gaseous effluent from step (a) with an organic liquid showing selectivity for the absorption of acetylene and selected from the group consisting of dimethyl formamide, butyrolactone, tetraethyl dimethyl glycol ether and N-methylpyrrolidone, and recovering from said organic liquid a crude acetylene containing hydrocarbons of three to more carbon atoms and traces of water;
  • step (c) removing from the gaseous effluent from step (c) substantially all of the hydrocarbons containing three to five carbon atoms accompanying the acetylene by washing the crude acetylene obtained from step (c) with toluene;
  • step (d) recovering dissolved acetylene from the toluene obtained from step (d) by heating said toluene to temperatures ranging from 0 to 40 C. and recycling the recovered acetylene to the gaseous eflluent from step (b);
  • step (e) distilling the toluene wash liquid obtained from step (e), thereby producing an overhead product consisting of hydrocarbons and a bottoms product methanol/water phase still containing traces of consisting of pure toluene which is recycled to step hydrocarbons and acetylene, (d) as fresh wash liquid.
  • step (d) distilling said methanol/water phase to give water 2.
  • step (b) loading the gaseous effluent from step (b) with methanol vapor and condensing out of said laden effluent a liquid mixture comprising methanol, water and a hydrocarbon mixture consisting essenl0 tially of hydrocarbons of more than five carbon atoms,
  • step (ca) separating the liquid effluent from step (ca) in a separating vessel into a hydrocarbon phase and a (cc), said desorbed acetylene being laden with methanol vapor not condensed in said step (cc), to the condensation step (ca).
  • said gaseous hydrocarbon is natural gas consisting essentially of methane.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US47964A 1969-07-07 1970-06-22 Production of acetylene Expired - Lifetime US3686344A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1934304A DE1934304C3 (de) 1969-07-07 1969-07-07 Verfahren zur Gewinnung von Acetylen

Publications (1)

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US3686344A true US3686344A (en) 1972-08-22

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US47964A Expired - Lifetime US3686344A (en) 1969-07-07 1970-06-22 Production of acetylene

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US (1) US3686344A (de)
AT (1) AT296942B (de)
BE (1) BE752891A (de)
DE (1) DE1934304C3 (de)
NL (1) NL7009299A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367363A (en) * 1980-12-23 1983-01-04 Gaf Corporation Production of acetylene
US4701190A (en) * 1985-11-07 1987-10-20 Linde Aktiengesellschaft Process for recovering methylacetylene and/or propadiene
US4740222A (en) * 1982-05-03 1988-04-26 Advanced Extraction Technologies, Inc. Recovery and purification of hydrogen from refinery and petrochemical off-gas streams
US4743282A (en) * 1982-05-03 1988-05-10 Advanced Extraction Technologies, Inc. Selective processing of gases containing olefins by the mehra process
US4788379A (en) * 1980-12-23 1988-11-29 Gaf Corporation Production of acetylene
US5804689A (en) * 1995-01-30 1998-09-08 Linde Aktiengesellschaft Process for recovering acetylene from hydrocarbons by thermal cracking
US20090260657A1 (en) * 2004-12-16 2009-10-22 Basf Aktiengesellschaft Method for cleaning deposits from equipment that have accumulated during a method for recovering nmp, by the introduction of hot water and agitation
CN109503310A (zh) * 2018-11-30 2019-03-22 西南化工研究设计院有限公司 一种天然气制备高浓度乙炔和氢气的工艺

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA573349A (en) * 1959-03-31 Wolfram Arthur Process for the separation of higher acetylene hydrocarbons
US2894602A (en) * 1955-09-24 1959-07-14 Montedison Spa Separation of acetylene from methane cracking gases by means of a selective solvent
GB834419A (en) * 1955-05-13 1960-05-11 Hoechst Ag Process and apparatus for carrying out chemical reactions at high temperatures
US3026969A (en) * 1958-10-02 1962-03-27 Belge Produits Chimiques Sa Gas treating process
US3174292A (en) * 1960-05-27 1965-03-23 Union Carbide Corp Acetylene recovery process
US3405192A (en) * 1964-02-01 1968-10-08 Linde Eismasch Ag Process for obtaining pure acetylene
US3531915A (en) * 1967-10-27 1970-10-06 Basf Ag Removing water vapor from cracked gases

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA573349A (en) * 1959-03-31 Wolfram Arthur Process for the separation of higher acetylene hydrocarbons
GB834419A (en) * 1955-05-13 1960-05-11 Hoechst Ag Process and apparatus for carrying out chemical reactions at high temperatures
US2894602A (en) * 1955-09-24 1959-07-14 Montedison Spa Separation of acetylene from methane cracking gases by means of a selective solvent
US3026969A (en) * 1958-10-02 1962-03-27 Belge Produits Chimiques Sa Gas treating process
US3174292A (en) * 1960-05-27 1965-03-23 Union Carbide Corp Acetylene recovery process
US3405192A (en) * 1964-02-01 1968-10-08 Linde Eismasch Ag Process for obtaining pure acetylene
US3531915A (en) * 1967-10-27 1970-10-06 Basf Ag Removing water vapor from cracked gases

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367363A (en) * 1980-12-23 1983-01-04 Gaf Corporation Production of acetylene
US4788379A (en) * 1980-12-23 1988-11-29 Gaf Corporation Production of acetylene
US4740222A (en) * 1982-05-03 1988-04-26 Advanced Extraction Technologies, Inc. Recovery and purification of hydrogen from refinery and petrochemical off-gas streams
US4743282A (en) * 1982-05-03 1988-05-10 Advanced Extraction Technologies, Inc. Selective processing of gases containing olefins by the mehra process
US4701190A (en) * 1985-11-07 1987-10-20 Linde Aktiengesellschaft Process for recovering methylacetylene and/or propadiene
US5804689A (en) * 1995-01-30 1998-09-08 Linde Aktiengesellschaft Process for recovering acetylene from hydrocarbons by thermal cracking
US20090260657A1 (en) * 2004-12-16 2009-10-22 Basf Aktiengesellschaft Method for cleaning deposits from equipment that have accumulated during a method for recovering nmp, by the introduction of hot water and agitation
CN109503310A (zh) * 2018-11-30 2019-03-22 西南化工研究设计院有限公司 一种天然气制备高浓度乙炔和氢气的工艺

Also Published As

Publication number Publication date
DE1934304A1 (de) 1971-01-21
DE1934304C3 (de) 1979-04-05
AT296942B (de) 1972-03-10
BE752891A (fr) 1971-01-04
DE1934304B2 (de) 1978-03-09
NL7009299A (de) 1971-01-11

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