US3271298A - Thermal cracking of paraffins to aromatics - Google Patents
Thermal cracking of paraffins to aromatics Download PDFInfo
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- US3271298A US3271298A US261878A US26187863A US3271298A US 3271298 A US3271298 A US 3271298A US 261878 A US261878 A US 261878A US 26187863 A US26187863 A US 26187863A US 3271298 A US3271298 A US 3271298A
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- hydrocarbons
- hydrocarbon
- thermal cracking
- aromatic hydrocarbons
- aromatics
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- 238000004227 thermal cracking Methods 0.000 title claims description 19
- 229930195733 hydrocarbon Natural products 0.000 claims description 55
- 150000002430 hydrocarbons Chemical class 0.000 claims description 55
- 150000004945 aromatic hydrocarbons Chemical class 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 20
- 239000004215 Carbon black (E152) Substances 0.000 claims description 19
- 239000012188 paraffin wax Substances 0.000 claims description 11
- 229920006395 saturated elastomer Polymers 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000005336 cracking Methods 0.000 claims description 2
- 125000000753 cycloalkyl group Chemical group 0.000 description 26
- 238000006243 chemical reaction Methods 0.000 description 13
- 125000004432 carbon atom Chemical group C* 0.000 description 11
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- RWGFKTVRMDUZSP-UHFFFAOYSA-N cumene Chemical compound CC(C)C1=CC=CC=C1 RWGFKTVRMDUZSP-UHFFFAOYSA-N 0.000 description 8
- NNBZCPXTIHJBJL-UHFFFAOYSA-N decalin Chemical compound C1CCCC2CCCCC21 NNBZCPXTIHJBJL-UHFFFAOYSA-N 0.000 description 6
- CXWXQJXEFPUFDZ-UHFFFAOYSA-N tetralin Chemical compound C1=CC=C2CCCCC2=C1 CXWXQJXEFPUFDZ-UHFFFAOYSA-N 0.000 description 6
- 239000003701 inert diluent Substances 0.000 description 5
- LAIUFBWHERIJIH-UHFFFAOYSA-N 3-Methylheptane Chemical compound CCCCC(C)CC LAIUFBWHERIJIH-UHFFFAOYSA-N 0.000 description 4
- 125000003118 aryl group Chemical group 0.000 description 4
- OCKPCBLVNKHBMX-UHFFFAOYSA-N butylbenzene Chemical compound CCCCC1=CC=CC=C1 OCKPCBLVNKHBMX-UHFFFAOYSA-N 0.000 description 4
- 239000003085 diluting agent Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 125000001424 substituent group Chemical group 0.000 description 4
- -1 substituent hydrocarbons Chemical class 0.000 description 4
- QNLZIZAQLLYXTC-UHFFFAOYSA-N 1,2-dimethylnaphthalene Chemical compound C1=CC=CC2=C(C)C(C)=CC=C21 QNLZIZAQLLYXTC-UHFFFAOYSA-N 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- IMNFDUFMRHMDMM-UHFFFAOYSA-N N-Heptane Chemical compound CCCCCCC IMNFDUFMRHMDMM-UHFFFAOYSA-N 0.000 description 3
- 150000001925 cycloalkenes Chemical class 0.000 description 3
- 238000004821 distillation Methods 0.000 description 3
- DMEGYFMYUHOHGS-UHFFFAOYSA-N heptamethylene Natural products C1CCCCCC1 DMEGYFMYUHOHGS-UHFFFAOYSA-N 0.000 description 3
- RGSFGYAAUTVSQA-UHFFFAOYSA-N pentamethylene Natural products C1CCCC1 RGSFGYAAUTVSQA-UHFFFAOYSA-N 0.000 description 3
- VPHBYBUYWBZLEX-UHFFFAOYSA-N 1,2-dipropylbenzene Chemical compound CCCC1=CC=CC=C1CCC VPHBYBUYWBZLEX-UHFFFAOYSA-N 0.000 description 2
- CTMHWPIWNRWQEG-UHFFFAOYSA-N 1-methylcyclohexene Chemical compound CC1=CCCCC1 CTMHWPIWNRWQEG-UHFFFAOYSA-N 0.000 description 2
- AFABGHUZZDYHJO-UHFFFAOYSA-N 2-Methylpentane Chemical compound CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 description 2
- GXDHCNNESPLIKD-UHFFFAOYSA-N 2-methylhexane Chemical compound CCCCC(C)C GXDHCNNESPLIKD-UHFFFAOYSA-N 0.000 description 2
- SFRKSDZMZHIISH-UHFFFAOYSA-N 3-ethylhexane Chemical compound CCCC(CC)CC SFRKSDZMZHIISH-UHFFFAOYSA-N 0.000 description 2
- VLJXXKKOSFGPHI-UHFFFAOYSA-N 3-methylhexane Chemical compound CCCC(C)CC VLJXXKKOSFGPHI-UHFFFAOYSA-N 0.000 description 2
- PFEOZHBOMNWTJB-UHFFFAOYSA-N 3-methylpentane Chemical compound CCC(C)CC PFEOZHBOMNWTJB-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- HGCIXCUEYOPUTN-UHFFFAOYSA-N cyclohexene Chemical compound C1CCC=CC1 HGCIXCUEYOPUTN-UHFFFAOYSA-N 0.000 description 2
- ZSWFCLXCOIISFI-UHFFFAOYSA-N cyclopentadiene Chemical compound C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 description 2
- LPIQUOYDBNQMRZ-UHFFFAOYSA-N cyclopentene Chemical compound C1CC=CC1 LPIQUOYDBNQMRZ-UHFFFAOYSA-N 0.000 description 2
- DIOQZVSQGTUSAI-UHFFFAOYSA-N decane Chemical compound CCCCCCCCCC DIOQZVSQGTUSAI-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- PQNFLJBBNBOBRQ-UHFFFAOYSA-N indane Chemical compound C1=CC=C2CCCC2=C1 PQNFLJBBNBOBRQ-UHFFFAOYSA-N 0.000 description 2
- UAEPNZWRGJTJPN-UHFFFAOYSA-N methylcyclohexane Chemical compound CC1CCCCC1 UAEPNZWRGJTJPN-UHFFFAOYSA-N 0.000 description 2
- GDOPTJXRTPNYNR-UHFFFAOYSA-N methylcyclopentane Chemical compound CC1CCCC1 GDOPTJXRTPNYNR-UHFFFAOYSA-N 0.000 description 2
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 2
- BKIMMITUMNQMOS-UHFFFAOYSA-N nonane Chemical compound CCCCCCCCC BKIMMITUMNQMOS-UHFFFAOYSA-N 0.000 description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 2
- BGXXXYLRPIRDHJ-UHFFFAOYSA-N tetraethylmethane Chemical compound CCC(CC)(CC)CC BGXXXYLRPIRDHJ-UHFFFAOYSA-N 0.000 description 2
- 239000008096 xylene Substances 0.000 description 2
- 150000003738 xylenes Chemical class 0.000 description 2
- VIDOPANCAUPXNH-UHFFFAOYSA-N 1,2,3-triethylbenzene Chemical class CCC1=CC=CC(CC)=C1CC VIDOPANCAUPXNH-UHFFFAOYSA-N 0.000 description 1
- TXNWMICHNKMOBR-UHFFFAOYSA-N 1,2-dimethylcyclohexene Chemical compound CC1=C(C)CCCC1 TXNWMICHNKMOBR-UHFFFAOYSA-N 0.000 description 1
- UJUUQKOWULNFNG-UHFFFAOYSA-N 1,3-dimethylphenanthrene Chemical compound C1=CC=C2C3=CC(C)=CC(C)=C3C=CC2=C1 UJUUQKOWULNFNG-UHFFFAOYSA-N 0.000 description 1
- QMFJIJFIHIDENY-UHFFFAOYSA-N 1-Methyl-1,3-cyclohexadiene Chemical compound CC1=CC=CCC1 QMFJIJFIHIDENY-UHFFFAOYSA-N 0.000 description 1
- QCEYTMQUKGCECE-UHFFFAOYSA-N 1-cyclodecyl-1-methylcyclodecane Chemical compound CC1(CCCCCCCCC1)C1CCCCCCCCC1 QCEYTMQUKGCECE-UHFFFAOYSA-N 0.000 description 1
- HYFLWBNQFMXCPA-UHFFFAOYSA-N 1-ethyl-2-methylbenzene Chemical class CCC1=CC=CC=C1C HYFLWBNQFMXCPA-UHFFFAOYSA-N 0.000 description 1
- ATQUFXWBVZUTKO-UHFFFAOYSA-N 1-methylcyclopentene Chemical compound CC1=CCCC1 ATQUFXWBVZUTKO-UHFFFAOYSA-N 0.000 description 1
- BSZXAFXFTLXUFV-UHFFFAOYSA-N 1-phenylethylbenzene Chemical compound C=1C=CC=CC=1C(C)C1=CC=CC=C1 BSZXAFXFTLXUFV-UHFFFAOYSA-N 0.000 description 1
- PSABUFWDVWCFDP-UHFFFAOYSA-N 2,2-dimethylheptane Chemical compound CCCCCC(C)(C)C PSABUFWDVWCFDP-UHFFFAOYSA-N 0.000 description 1
- KYCZJIBOPKRSOV-UHFFFAOYSA-N 4-ethyl-2-methylhexane Chemical compound CCC(CC)CC(C)C KYCZJIBOPKRSOV-UHFFFAOYSA-N 0.000 description 1
- SUMOGCZUNXXYRP-UHFFFAOYSA-N 4-methylpentylbenzene Chemical compound CC(C)CCCC1=CC=CC=C1 SUMOGCZUNXXYRP-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- 125000002015 acyclic group Chemical group 0.000 description 1
- 125000002723 alicyclic group Chemical group 0.000 description 1
- 150000001338 aliphatic hydrocarbons Chemical group 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- WAAUXNSLVPBVRA-UHFFFAOYSA-N cyclopentylmethylbenzene Chemical compound C=1C=CC=CC=1CC1CCCC1 WAAUXNSLVPBVRA-UHFFFAOYSA-N 0.000 description 1
- CZZYITDELCSZES-UHFFFAOYSA-N diphenylmethane Chemical compound C=1C=CC=CC=1CC1=CC=CC=C1 CZZYITDELCSZES-UHFFFAOYSA-N 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002732 mesitylenes Chemical class 0.000 description 1
- GYNNXHKOJHMOHS-UHFFFAOYSA-N methyl-cycloheptane Natural products CC1CCCCCC1 GYNNXHKOJHMOHS-UHFFFAOYSA-N 0.000 description 1
- 150000002790 naphthalenes Chemical class 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 229930195734 saturated hydrocarbon Natural products 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- PXXNTAGJWPJAGM-UHFFFAOYSA-N vertaline Natural products C1C2C=3C=C(OC)C(OC)=CC=3OC(C=C3)=CC=C3CCC(=O)OC1CC1N2CCCC1 PXXNTAGJWPJAGM-UHFFFAOYSA-N 0.000 description 1
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
- C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2/00—Preparation of hydrocarbons from hydrocarbons containing a smaller number of carbon atoms
Definitions
- the present invention relates to a process for the thermal cracking of hydrocarbons. Further, the present invention relates to a process for the production of aromatic hydrocarbons. More particularly, the present invention relates to a process for the thermal cracking of paraffinic hydrocarbons to obtain a cracked product of increased aromatic hydrocarbon content.
- the pressure usually is within the range of from atmospheric to 1000 p.s.i.g., but preferably within the rang of to 300 p.s.i.g.
- an inert diluent preferably steam.
- an inert diluent When an inert diluent is used it generally is used in an amount of 0.1 to 2.0 parts by weight of diluent per part by weight of hydrocarbon feed.
- a diluent to hydrocarbon feed weight ratio of 0.2: l to 0.8 :1 is used in the present invention.
- the cyclic hydrocarbons useful in promoting the formation of aromatic hydrocarbons in accordance with the present invention includes hydrocarbon substituted aromatic hydrocarbons, partially saturated cyclic hydrocar- States Patent bons and saturated cyclic hydrocarbons.
- the hydrocarbon substituted aromatics include both monoand polynuclear aromatics.
- Substituents to the aromatic nucleus may be aryl, alicyclic or acyclic and may be saturated or unsaturated.
- the primary limitation on the substituent hydrocarbons is that there be at least one hydrogen atom attached to the substituent carbon adjacent the aromatic nucleus.
- There may be any number of substituents to the aromatic nucleus such as in dialkylbenzenes, trialkylbenzenes and the like.
- hydrocarbon substituted aromatic hydrocarbons are toluene,
- mesitylenes l-methylnaphthalene, 1,2-dimethylnaphthalene, xylenes,
- triethylbenzenes 1,3-dimethylphenanthrene, 1,2-di-n-propylbenzene, 1-phenyl-4-methylpentane, cyclopentylphenylmethane, 1-cyclopentyl-Z-phenylethane, diphenylmethane, 1,1-diphenylethane, 1-phenyI-Z-methylpropene-Z, l-methyl-S-(propen-2-yl)benzene and the like.
- a preferred group of substituted aromatic hydrocarbons are the monoand di-alkyl substituted benzenes and naphthalenes in which the alkyl substituents have no greater than 10 carbon atoms.
- These preferred hydrocarbon substituted aromatic hydrocarbons are illustrated by the following non-limiting examples: l-methylnaphthalene, toluene, cumene, Xylenes, isopropylbenzene, n-butylbenzene, dimethylnaphthalenes, dibutylbenzenes, methylethylbenzenes, dipropylbenzenes and the like.
- the partially satua rated cyclic hydrocarbons are the cyclic hydrocarbons more saturated than aromatics, but yet not completely saturated and includes both mono-nuclear and poly-nuclear compounds.
- the mono-nuclear cyclic hydrocarbons include the cycloolefins and cyclodiolefins.
- Poly-nuclear cyclic hydrocarbons include the dicycloolefins and dicyclodiolefins, and the fused ring aromatics in which at least one ring is partially or completely saturated, i.e., tetralin and the like.
- the partially saturated cyclic hydrocarbons are illustrated by the following non-limiting examples:
- the preferred partially saturated cyclic hydrocarbons are the cyclodiolefins, cycloolefins and partially saturated dinuclear fused ring aromatics.
- This preferred group of compounds include the following non-limiting examples: cyclohexene, cyclopentene, methylcyclopentene, methylcyclohexene, cyclopentadiene, methylcyclohexadiene, dimethylcyclohexene, Tetralin, indane, and the like.
- Completely saturated cyclic hydrocarbons include the cycloparaffins, dicycloparaffins and the completely saturated fused ring cyclic hydrocarbons.
- hydrocarbons are cyclopentane, cyclohexane, cycloheptane, methylcyclopentane, methylcyclohexane, decahydronaphthalene, methylbicyclodecane, ethylbicyclodecane, and the like.
- the preferred hydrocarbons within this group are the cycloparafiins of 5 and 6 carbon atoms in the ring and having either no substituents or having aliphatic hydrocarbon substituents of 1 to 6 carbon atoms and the saturated di-nuclear fused ring cyclic hydrocarbons of 8 to 12 carbon atoms such as decahydronaphthalene, either unsubstituted or having alkyl substituents of 1 to 6 carbon atoms.
- the amount of cyclic hydrocarbon useful in the present is within the range of approximately 0.1 to mol percent of the paraffin hydrocarbons in the feed. However, it is preferred that the amount of cyclic hydrocarbon be within the range of from approximately 0.5 to 5 mol percent of the paraflin hydrocarbons in the feed.
- the feedstocks to the present process may contain as an impurity small amounts of hydrocarbon substituted aromatics, partially saturated cyclic-hydrocarbons or completely saturated cyclic hydrocarbons. 'If such is present in the feed initially, the amount of such material added to the thermal reaction zone is reduced proportionately.
- the feedstocks which may be processed in accordance with the present invention are paraflinic fractions containing 20 to 100% by weight of parafiin hydrocarbons.
- paraffin hydrocarbons is meant the non-cyclic saturated hydrocarbons.
- the feedstock will be a paraflin fraction of 90 to 100% by weight parafiin hydrocarbons.
- the paraflin hydrocarbons may be relatively low molecular weight liquids or high molecular weight waxy solids.
- the paraffinic hydrocarbons will have at least 6 car-bon atoms and may be straightchain or branched-chain.
- parafiinic hydrocarbons within the scope of the present invention are n-hexane, 2-methylpentane, 3- methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, Z-ethylpentane, n-octane, Z-methylheptane, 2-ethylhexane, 3-methylheptane, 3-ethylhexane, n-nonane, 2,2- dimethylheptane, 2-methyl-4-ethylhexane, 3,3-diethylpentane, n-decane, and the like on up to and including nand iso-paraffins of 70 carbon atoms and higher.
- the preferred parafiin hydrocarbons are those containing 6 to 40 carbon atoms and are either straight-chain or branched-chain.
- the impurities may include any hydrocarbon such as paraffin hydrocarbons of less than 6 carbon atoms, olefins, aromatics, naphthenes and the like, as well as diluents and inert materials.
- spaces velocities of 0.5 to 10 parts by volume of feed per part by volume of internal reaction space generally is used. However, it is preferred that the space velocity be Within the range of 2 to 6 parts by volume of paraffinic feed per part by volume of internal reaction space.
- Example I The paraffinic feedstock used in this demonstration was 100% paralfinic hydrocarbons having a molecular weight range of about 60 to 700. This parafiinic feed was passed through 35 feet of inch stainless steel tubing at a rate of 4.4 pounds of feed per hour. The
- parafiinic feed was passed into the reaction tube concurrently with steam in a ratio of 0.4 pound of steam per pound of feed.
- Five mol percent of toluene was introduced concurrently with the paraffinic feed and steam.
- the inlet temperature of the 35 foot reaction tube was approximately 450 C. and the exit temperature 602 C.
- the pressure within the reaction tube was maintained at approximately 11.3 p.s.i.g. A conversion of 73.5% 'was obtained.
- a C -C fraction was obtained from the cracked oil product by distillation. This fraction represented 14.5% of the total product and was found to contain 7.4% by weight of aromatic hydrocarbons. The percent of aromatic hydrocarbons was calculated on a toluene-free basis.
- Example 11 Example I was substantially repeated with the exception that 5 mol percent of cumene was added and the feed rate was 4.6 pounds per hour. Conversion was approximately 76.4%. A C -C fraction was obtained from the cracked oil product by distillation. This fraction represented 11.0% by weight of the total cracked oil product and was found to contain 4.2% by wieght of aromatic hydrocarbons. The percent of aromatic hydrocarbons was calculated on a cumene-free basis.
- Example 111 Example I was substantially repeated with the exception that 5 mol percent of Decalin was added and the feed rate was 4.7 pounds per hour. Conversion was approximately 77.5%. A C C fraction was obtained from the cracked oil product by distillation. This fraction represented 12.8% by weight of the total cracked oil product and was found to contain 4.37% by weight of aromatic hydrocarbons. The percent of aromatic hydrocarbons was calculated on a Decalin-free basis.
- Example IV Example I was substantially repeated with the exception that no cyclic hydrocarbon was added. Conversion was approximately 73%. The cracked oil product was fractionated to obtain a C -C fraction. This fraction represented 9.2% by weight of the total cracked oil product and was found to contain 1.5% by weight of aromatic hydrocarbons.
- the equipment which may be used in carrying out the present invention is not critical. Any conventional thermal cracking equipment may be used. It is only necessary that the equipment 'be such as to withstand the pressures and temperatures of the reactions and that the equipment follow good engineering principles.
- a process for increasing the production of aromatic hydrocarbons from the thermal cracking of paraffin hydrocarbons which comprises adding 0.1 to 10 mol percent of a hydrocarbon selected from the group consisting of hydrocarbon substituted aromatic hydrocarbons, partially saturated cyclic hydrocarbons and saturated cyclic hydrocarbons to a noncatalytic thermal cracking zone concurrently with a paraffin hydrocarbon feed containing less than 1% of non-parafiin hydrocarbons, said cracking zone being maintained at a temperature of 400-900 C. and a pressure of atmospheric to 1000 p.s.1.g.
- cyclic hydrocarbon is a hydrocarbon substituted aromatic hydrocarbon selected from the group consisting of monoalkylbenzenes, monoalkylnaphthalenes, dialkylbenz/enes, and dialkylnaphthalenes and is one having no greater than 10 carbon atoms in the hydrocarbon substituents.
- cyclic hydrocarbon is a partially saturated cyclic hydrocarbon selected from the group consisting of cycloolefins, cyclodiolefins and partially saturated di-nuclear fused ring aromatics.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Description
3,271,298 THERMAL CRACKING F PARAFFINS T0 AROMATICS Clarence L. Dulaney and Marvin Lee Owens, Jr., Texas City, Tex., assignors to Monsanto Company, a corporation of Delaware N0 Drawing. Filed Feb. 28, 1963, Ser. No. 261,878
10 Claims. (Cl. 208-106) The present invention relates to a process for the thermal cracking of hydrocarbons. Further, the present invention relates to a process for the production of aromatic hydrocarbons. More particularly, the present invention relates to a process for the thermal cracking of paraffinic hydrocarbons to obtain a cracked product of increased aromatic hydrocarbon content.
Because of the relatively low economic value of paraffin hydrocarbons, there is a continuous search for methods whereby these hydrocarbons may be converted into more valuable materials. Among the more valuable materials which may be produced from parafiins are olefin and aromatic hydrocarbons. Thermal cracking of paraflin hydrocarbons is one of the well known and widely used processes whereby the paraffins are converted to more valuable olefinic hydrocarbons. In addition to the olefinic hydrocarbons, a very small amount of aromatic hydrocarbons are usually produced by the thermal cracking of paraffins. However, the amount of aromatic hydrocarbons produced is generally so small that the value of the cracked products is not enhanced despite the higher value of the aromatic hydrocarbons. Because of the high value of the aromatics, the greater the amount of such hydrocarbons which can be produced from the thermal cracking of parafiins the greater the value of the cracked prodnot.
It is an object of the present invention to provide a new and improved process for the thermal cracking of paraflin hydrocarbons. Another object of the present invention is to provide a process for the thermal cracking of paraflin hydrocarbons whereby the quantity of aromatic hydrocarbons produced is significantly increased. Still another object of the present invention is to provide a process for the production of aromatic hydrocarbons from paraifin hydrocarbons. Additional objects will become apparent from the following description of the invention herein disclosed.
In fufillment of these and other objects, it has been found that there is a substantial increase in the yield of aromatic hydrocarbons from the thermal cracking of paraffin hydrocarbons when a minor amount of a cyclic hydrocarbon, selected from the group consisting of hydrocarbon substituted aromatic hydrocarbons partially saturated cyclic hydrocarbons and saturated cyclic hydrocarbons, is added to the thermal cracking zone concurrently with a paraflin hydrocarbon feed. The thermal cracking may be carried out under any conditions of temperature and pressure conventional to such processes. Most often the temperature will be within the range of 400 to 900 C. with temperatures of from 500 to 800 C. being preferred. The pressure usually is within the range of from atmospheric to 1000 p.s.i.g., but preferably within the rang of to 300 p.s.i.g. Ordinarily, the thermal cracking of parafiin hydrocarbon is carried out in the presence of an inert diluent, preferably steam. When an inert diluent is used it generally is used in an amount of 0.1 to 2.0 parts by weight of diluent per part by weight of hydrocarbon feed. Preferably, a diluent to hydrocarbon feed weight ratio of 0.2: l to 0.8 :1 is used in the present invention.
The cyclic hydrocarbons useful in promoting the formation of aromatic hydrocarbons in accordance with the present invention includes hydrocarbon substituted aromatic hydrocarbons, partially saturated cyclic hydrocar- States Patent bons and saturated cyclic hydrocarbons. The hydrocarbon substituted aromatics include both monoand polynuclear aromatics. Substituents to the aromatic nucleus may be aryl, alicyclic or acyclic and may be saturated or unsaturated. The primary limitation on the substituent hydrocarbons is that there be at least one hydrogen atom attached to the substituent carbon adjacent the aromatic nucleus. There may be any number of substituents to the aromatic nucleus such as in dialkylbenzenes, trialkylbenzenes and the like. Several non-limiting examples of hydrocarbon substituted aromatic hydrocarbons are toluene,
cumene,
styrene,
n-butylbenzene,
mesitylenes, l-methylnaphthalene, 1,2-dimethylnaphthalene, xylenes,
triethylbenzenes, 1,3-dimethylphenanthrene, 1,2-di-n-propylbenzene, 1-phenyl-4-methylpentane, cyclopentylphenylmethane, 1-cyclopentyl-Z-phenylethane, diphenylmethane, 1,1-diphenylethane, 1-phenyI-Z-methylpropene-Z, l-methyl-S-(propen-2-yl)benzene and the like.
A preferred group of substituted aromatic hydrocarbons are the monoand di-alkyl substituted benzenes and naphthalenes in which the alkyl substituents have no greater than 10 carbon atoms. These preferred hydrocarbon substituted aromatic hydrocarbons are illustrated by the following non-limiting examples: l-methylnaphthalene, toluene, cumene, Xylenes, isopropylbenzene, n-butylbenzene, dimethylnaphthalenes, dibutylbenzenes, methylethylbenzenes, dipropylbenzenes and the like. The partially satua rated cyclic hydrocarbons, for the purposes of the present invention, are the cyclic hydrocarbons more saturated than aromatics, but yet not completely saturated and includes both mono-nuclear and poly-nuclear compounds. The mono-nuclear cyclic hydrocarbons include the cycloolefins and cyclodiolefins. Poly-nuclear cyclic hydrocarbons include the dicycloolefins and dicyclodiolefins, and the fused ring aromatics in which at least one ring is partially or completely saturated, i.e., tetralin and the like. The partially saturated cyclic hydrocarbons are illustrated by the following non-limiting examples:
The preferred partially saturated cyclic hydrocarbons are the cyclodiolefins, cycloolefins and partially saturated dinuclear fused ring aromatics. This preferred group of compounds include the following non-limiting examples: cyclohexene, cyclopentene, methylcyclopentene, methylcyclohexene, cyclopentadiene, methylcyclohexadiene, dimethylcyclohexene, Tetralin, indane, and the like. Completely saturated cyclic hydrocarbons include the cycloparaffins, dicycloparaffins and the completely saturated fused ring cyclic hydrocarbons. Several non-limiting examples of such hydrocarbons are cyclopentane, cyclohexane, cycloheptane, methylcyclopentane, methylcyclohexane, decahydronaphthalene, methylbicyclodecane, ethylbicyclodecane, and the like. The preferred hydrocarbons within this group are the cycloparafiins of 5 and 6 carbon atoms in the ring and having either no substituents or having aliphatic hydrocarbon substituents of 1 to 6 carbon atoms and the saturated di-nuclear fused ring cyclic hydrocarbons of 8 to 12 carbon atoms such as decahydronaphthalene, either unsubstituted or having alkyl substituents of 1 to 6 carbon atoms.
The amount of cyclic hydrocarbon useful in the present, in most instances, is within the range of approximately 0.1 to mol percent of the paraffin hydrocarbons in the feed. However, it is preferred that the amount of cyclic hydrocarbon be within the range of from approximately 0.5 to 5 mol percent of the paraflin hydrocarbons in the feed. In many instances, the feedstocks to the present process may contain as an impurity small amounts of hydrocarbon substituted aromatics, partially saturated cyclic-hydrocarbons or completely saturated cyclic hydrocarbons. 'If such is present in the feed initially, the amount of such material added to the thermal reaction zone is reduced proportionately.
The feedstocks which may be processed in accordance with the present invention are paraflinic fractions containing 20 to 100% by weight of parafiin hydrocarbons. By paraffin hydrocarbons is meant the non-cyclic saturated hydrocarbons. Preferably the feedstock will be a paraflin fraction of 90 to 100% by weight parafiin hydrocarbons. The paraflin hydrocarbons may be relatively low molecular weight liquids or high molecular weight waxy solids. Generally, the paraffinic hydrocarbons will have at least 6 car-bon atoms and may be straightchain or branched-chain. Several non-limiting examples of parafiinic hydrocarbons within the scope of the present invention are n-hexane, 2-methylpentane, 3- methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, Z-ethylpentane, n-octane, Z-methylheptane, 2-ethylhexane, 3-methylheptane, 3-ethylhexane, n-nonane, 2,2- dimethylheptane, 2-methyl-4-ethylhexane, 3,3-diethylpentane, n-decane, and the like on up to and including nand iso-paraffins of 70 carbon atoms and higher. The preferred parafiin hydrocarbons are those containing 6 to 40 carbon atoms and are either straight-chain or branched-chain. In parafiin fractions containing less than 100% paraflin hydrocarbons, the impurities may include any hydrocarbon such as paraffin hydrocarbons of less than 6 carbon atoms, olefins, aromatics, naphthenes and the like, as well as diluents and inert materials.
In carrying out the practice of the present invention, spaces velocities of 0.5 to 10 parts by volume of feed per part by volume of internal reaction space generally is used. However, it is preferred that the space velocity be Within the range of 2 to 6 parts by volume of paraffinic feed per part by volume of internal reaction space.
In order to demonstrate the efficacy of the present invention, the following examples are presented.
Example I The paraffinic feedstock used in this demonstration was 100% paralfinic hydrocarbons having a molecular weight range of about 60 to 700. This parafiinic feed was passed through 35 feet of inch stainless steel tubing at a rate of 4.4 pounds of feed per hour. The
parafiinic feed was passed into the reaction tube concurrently with steam in a ratio of 0.4 pound of steam per pound of feed. Five mol percent of toluene was introduced concurrently with the paraffinic feed and steam. The inlet temperature of the 35 foot reaction tube was approximately 450 C. and the exit temperature 602 C. The pressure within the reaction tube was maintained at approximately 11.3 p.s.i.g. A conversion of 73.5% 'was obtained. A C -C fraction was obtained from the cracked oil product by distillation. This fraction represented 14.5% of the total product and was found to contain 7.4% by weight of aromatic hydrocarbons. The percent of aromatic hydrocarbons was calculated on a toluene-free basis.
Example 11 Example I was substantially repeated with the exception that 5 mol percent of cumene was added and the feed rate was 4.6 pounds per hour. Conversion was approximately 76.4%. A C -C fraction was obtained from the cracked oil product by distillation. This fraction represented 11.0% by weight of the total cracked oil product and was found to contain 4.2% by wieght of aromatic hydrocarbons. The percent of aromatic hydrocarbons was calculated on a cumene-free basis.
Example 111 Example I was substantially repeated with the exception that 5 mol percent of Decalin was added and the feed rate was 4.7 pounds per hour. Conversion was approximately 77.5%. A C C fraction was obtained from the cracked oil product by distillation. This fraction represented 12.8% by weight of the total cracked oil product and was found to contain 4.37% by weight of aromatic hydrocarbons. The percent of aromatic hydrocarbons was calculated on a Decalin-free basis.
Example IV Example I was substantially repeated with the exception that no cyclic hydrocarbon was added. Conversion was approximately 73%. The cracked oil product was fractionated to obtain a C -C fraction. This fraction represented 9.2% by weight of the total cracked oil product and was found to contain 1.5% by weight of aromatic hydrocarbons.
From the above examples, it is quite apparent that the present invention produces substantially increased yields of aromatic hydrocarbons. Further, it should be noted that in both instances in which cyclic hydrocarbons were added that significantly improved conversions of paraffinic hydrocarbons to cracked products were obtained.
The equipment which may be used in carrying out the present invention is not critical. Any conventional thermal cracking equipment may be used. It is only necessary that the equipment 'be such as to withstand the pressures and temperatures of the reactions and that the equipment follow good engineering principles.
What is claimed is:
1. A process for increasing the production of aromatic hydrocarbons from the thermal cracking of paraffin hydrocarbons which comprises adding 0.1 to 10 mol percent of a hydrocarbon selected from the group consisting of hydrocarbon substituted aromatic hydrocarbons, partially saturated cyclic hydrocarbons and saturated cyclic hydrocarbons to a noncatalytic thermal cracking zone concurrently with a paraffin hydrocarbon feed containing less than 1% of non-parafiin hydrocarbons, said cracking zone being maintained at a temperature of 400-900 C. and a pressure of atmospheric to 1000 p.s.1.g.
2. The process of claim 1 wherein the thermal cracking is carried out in the presence of an inert diluent.
3. The process of claim 1 wherein the parafiin hydrocarbons in the feed contain 6 to 40 carbon atoms.
4. The process of claim 2 wherein the inert diluent is present in an amount of from 0.1 to 2.0 parts by weight of diluent per part by weight of hydrocarbon feed.
5. The process of claim 2 wherein the inert diluent is steam.
6. The process of claim 1 wherein the thermal reaction zone is maintained Within the temperature range of from 500 to 800 C. and the pressure is maintained within the range of from 5 to 300 p.s.i.g.
7. The process of claim 1 wherein the amount of cyclic hydrocarbon added is approximately 0.5 to 5 mol percent of the paraffin hydrocarbons in the feed.
8. The process of claim 1 wherein the cyclic hydrocarbon is a hydrocarbon substituted aromatic hydrocarbon selected from the group consisting of monoalkylbenzenes, monoalkylnaphthalenes, dialkylbenz/enes, and dialkylnaphthalenes and is one having no greater than 10 carbon atoms in the hydrocarbon substituents.
9. The process of claim 1 wherein the cyclic hydrocarbon is a partially saturated cyclic hydrocarbon selected from the group consisting of cycloolefins, cyclodiolefins and partially saturated di-nuclear fused ring aromatics.
References Cited by the Examiner UNITED STATES PATENTS 6/ 1945 Dorsett et al. 208132 9/1958 Smith et al. 208-132 DELBERT E. GANTZ, Primary Examiner.
ALPHONSO D. SULLIVAN, Examiner.
H. LEVINE, Assistant Examiner.
Claims (1)
1. A PROCESS FOR INCREASING THE PRODUCTION OF AROMATIC HYDROCARBONS FROM THE THERMAL CRACKING OF PARAFFIN HYDROCARBONS WHICH COMPRISES ADDING 0.1 TO 10 MOL PERCENT OF A HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF HYDROCARBON SUBSTITUTED AROMATIC HYDROCARBONS, PARTIALLY SATURATED CYCLIC HYDROCARBONS AND SATURATED CYCLIC HYDROCARBONS TO A NON-CATALYTIC THERMAL CRACKING ZONE CONCURRENTLY WITH A PARAFFIN HYDROCARBON FEED CONTAINING LESS THAN 1% OF NON-PARAFFIN HYDROCARBONS, SAID CRACKING ZONE BEING MAINTAINED AT A TEMPERATURE OF 400-900*C. AND A PRESSURE OF ATMOSPHERIC TO 1000 P.S.I.G.
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US261878A US3271298A (en) | 1963-02-28 | 1963-02-28 | Thermal cracking of paraffins to aromatics |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3714282A (en) * | 1970-07-09 | 1973-01-30 | Monsanto Co | Production of propylene and aromatic compounds from liquid feed streams |
US4520217A (en) * | 1981-12-10 | 1985-05-28 | Kinetics Technology International Corp. | Pyrolysis of natural gas liquids to aromatic hydrocarbons using a hot recycled gas |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2378067A (en) * | 1942-09-28 | 1945-06-12 | Petroleum Conversion Corp | Process of cracking petroleum |
US2852440A (en) * | 1954-06-24 | 1958-09-16 | Exxon Research Engineering Co | Production of aromatics and unsaturated hydrocarbons |
-
1963
- 1963-02-28 US US261878A patent/US3271298A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2378067A (en) * | 1942-09-28 | 1945-06-12 | Petroleum Conversion Corp | Process of cracking petroleum |
US2852440A (en) * | 1954-06-24 | 1958-09-16 | Exxon Research Engineering Co | Production of aromatics and unsaturated hydrocarbons |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3714282A (en) * | 1970-07-09 | 1973-01-30 | Monsanto Co | Production of propylene and aromatic compounds from liquid feed streams |
US4520217A (en) * | 1981-12-10 | 1985-05-28 | Kinetics Technology International Corp. | Pyrolysis of natural gas liquids to aromatic hydrocarbons using a hot recycled gas |
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