US2902427A - Hydroforming process - Google Patents

Hydroforming process Download PDF

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Publication number
US2902427A
US2902427A US555885A US55588555A US2902427A US 2902427 A US2902427 A US 2902427A US 555885 A US555885 A US 555885A US 55588555 A US55588555 A US 55588555A US 2902427 A US2902427 A US 2902427A
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United States
Prior art keywords
hydroforming
hydrogen
naphtha
boiling
recycle gas
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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.)
Expired - Lifetime
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US555885A
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English (en)
Inventor
Jr Albert B Welty
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ExxonMobil Technology and Engineering Co
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Exxon Research and Engineering Co
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Filing date
Publication date
Priority to BE567544D priority Critical patent/BE567544A/xx
Application filed by Exxon Research and Engineering Co filed Critical Exxon Research and Engineering Co
Priority to US555885A priority patent/US2902427A/en
Priority to GB39287/56A priority patent/GB798018A/en
Priority to FR1169620D priority patent/FR1169620A/fr
Priority to DEE13442A priority patent/DE1038218B/de
Application granted granted Critical
Publication of US2902427A publication Critical patent/US2902427A/en
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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
    • C10G35/00—Reforming naphtha
    • C10G35/04—Catalytic reforming
    • C10G35/06—Catalytic reforming characterised by the catalyst used
    • C10G35/085—Catalytic reforming characterised by the catalyst used containing platinum group metals or compounds thereof

Definitions

  • the present invention relates to improvements in hydroforming. More particularly, the present invention relates to the hydroforming of the naphtha in the presence of platinum in a fixed bed type of operation in which process the total naphtha is fractionated to obtain a low boiling fraction boiling up to 200 F. and a higher boiling fraction boiling above 200 F. and separately treating the said fractions under conditions which give improved results.
  • Hydroforming is a process in which a naphtha is treated in the presence of a solid catalytic material and hydrogen at ⁇ elevated temperatures and pressures with the result that the naphtha is improved in octane quality.
  • the principal reaction during hydroforming is the dehydrogenation of naphthenes present in the feed to the corresponding aromatics.
  • isomerization of normal paraihns to form isoparaiiins isomerization of alkylated cyclopentanes to cyclohexanes and some hydrocracking of the higher boiling paraflins to lower boiling products.
  • the process results in the net production of hydrogen but in any event there is no net consumption of hydrogen.
  • the catalyst employed in hydroforming may be in the form of fixed beds or the caalyst, in powdered form, may be employed utilizing the uidized solid technique.
  • the catalysts principally in commercial use are platinum ⁇ carried on alumina, or molybdenum oxide carried on alumina, the former being used in the form of fixed beds in a multi-stage operation with reheating between stages, while the latter is being employed in the form of a uidized bed.
  • hydroforming naphthas the optimum pressure is different for various boiling range naphthas.
  • high boiling naphthas are treated at moderately high pressures for best results.
  • the lower boiling naphthas, on the other hand, and in particular, the naphtha fractions boiling below 200 F. are treated at fairly low pressures for best results.
  • the rate of deactivating coke formation on the catalyst determines the length of time it may be used before regeneration is required and also the catalyst life or the length of time the catalyst may be employed before it is required to replace it and, therefore it is desirable to minimize this coke formation. It is common knowledge that the higher the hydrogen partial pressure, the lower the rate of coke formation will be. Therefore, higher pressure operations are required to produce aromatics in good yields with minimum coke formation and longer catalyst life.
  • the optimum operating pressure for high boiling naphthas such as those boiling above 200 F. will be considerably higher than that for low boiling naphthas such as particularly those boiling below about 200 F;
  • the object of the present invention is to hydroform light naphtha and heavy naphtha separately in the same equipment under optimum conditions for each.
  • the present invention provides means whereby this can be accomplished.
  • the hydroforming reaction is highly endothermic, that is, a large amount of heat is consumed when the reaction occurs.
  • the catalyst is disposed in one or more reactors in series and each reactor runs adiabatically, that is, no heat is put into or taken out of each reactor. Because of the large heat absorption by the reaction, there is a large temperature drop from the reactor inlet to outlet. This is undesirable because as the temperature drops, the rate of reaction decreases, and, in fact, this is the reason why it is necesessary to use more than one reactor in series and to reheat the hydrocarbon between reactors.
  • the temperature drop for ⁇ a given amount of reaction depends solely on the heat capacity of the vapors flowing through the bed. The higher the heat capacity, the lower the temperature drop will be. For this reason, it is desirable to recirculate as much recycle gas as practical from the standpoint of pressure drop through the system, compresso-r horsepower required, size of heat exchangers required, etc.
  • a recycle gas rate for example, of 6,000 s.c.f./bbl. of feed
  • the recycle gas actually has more heat-absorbing capacity than the feed itself.
  • the 6,000 scf/bbl. of recycle gas might have a heat capacity of about 180 B.t.u.s per F. whereas the barrel of feed would have a heat capacity of about B.t.u.s/ F.
  • the heat carrying capacity ofthe recycle gas depends -on'the gases of which it is composed.
  • hydrogen which is the principal volumetric component
  • a hydrocarbon like butane, for example, Vhas a relatively high -heat capacity.
  • the volumetric heat capacity of fbutane gas is approximately four times as high as that of hydrogen. The reason for this is the greaterweight of butane ⁇ per unit volume 'of gas as compared to hydrogen.
  • Recycle gas is a mixture of many gases-its 'principal component is hydrogen but it also contains substantial quantities of saturated hydrocarbons. Generally, it contains, on a volumetric basis, more methane than ethane, more ethane than propane, more propane than butane, etc. Usually, relatively little C6 or C7 hydrocarbons are present.
  • One way to increase the heat carrying capacity of this recycle gas then is to reduce rits hydrogen content and at the same time increase the content of highermolecular weight hydrocarbons, particularly Cs, Cs, Css, etc.
  • the hydroformed product is cooled toa ⁇ temperature of about 100 F. and thereafter the gas and liquid separated.
  • This gas is the product gas and a portion of it is also the recycle gas.
  • the composition of the recycle gas depends upon the quantities of gaseous materials being produced, to some extent on the nature of the liquid product, and very much upon the temperature and pressure of liquid-gas separation.
  • the product may be cooled not to the conventional 'temperature of about 100 E., but to some higher temperature, say .tofabout 300 F.
  • the following table shows the eifect of separator temperature on the specic gravity of the recycle gas and its heat carrying capacity, lin ⁇ a particular case.
  • naphtha feed l is introduced Ito the present system .through line '.1.
  • the naphtha is heated in furnace and thence withdrawn in vapor formvia line 4 and ycharged to a'separator or fractional distillation column V5, wherein a yfraction boiling from-Oto 200 P is 'withdrawn overhead throughline 6 and charged to a storage-drum 7, while va fraction boiling vfrom 200 F. 'to ⁇ say"400or F. is-withdrawn' as Ibottoms ⁇ from column 5, lineS andcharged tov a heavy naphtha storage ldrum 9.
  • This heated mixture is thence Withdrawn from furnace 11 through line 13 and charged to the first reactor 14 of a series of reactors.
  • the mixture of heavy naphtha vapors and hydrogen-containing gas passes through reactor 14 in contact with a bed of catalyst C at conditions of temperature and pressure and residence time as hereinafter more fully specified with the result that the naphtha undergoes at least partial hydroforming. Due to the fact that the reaction is highly endothermic there is subsequently a temperature decrease from the inlet to the outlet of reactor 14 so that product withdrawn via line 15 is reheated in the second furnace 16, withdrawn from said furnace and thence passed via line 17 to a second reactor 18 Where again the naphtha contacts a bed of catalyst C and undergoes further hydroforming.
  • the product is withdrawn from reactor 18 via line 19 and is reheated in a third furnace 20, withdrawn through line 21 and charged to a third reactor 22 also containing a bed of catalyst and wherein the hydroforming reaction is subsequently completed.
  • the product is withdrawn from reactor 22 through line 23, cooled in 24 to a temperature of about 100 F thence withdrawn through line 25 and charged to a separation drum 26.
  • From separation drum 26 recycled gas is recovered overhead via line 27, forced through a compressor 28 and charged via line 12 to line 10, as previously explained. Excess recycled gas may be ejected through line 33.
  • the hydroformed product is withdrawn from separator 26 through line 30, passes through valve 37, line 32 and valve 42 to a conventional stabilizing and rerunning system.
  • the ow of heavy naphtha from storage drum 9 is discontinued and light naphtha is withdrawn from storage drum 7 via valved line 34. It is mixed with recycled gas obtained via line 12 and line 12a and charged to furnace 11 wherein the mixture is heated to reaction temperatures and this mixture is then passed through the series of reactors in the same manner as that previously described in connection with the processing of the heavy naphtha with the exception that, as previously pointed out viz., that the system is now operated at a substantially lower pressure and the separator drum 26 is operated at a substantially higher ternperature by controlling the degree of cooling in cooler 24 so that the recycled gas recovered overhead from separator 26 via line 27 is at a substantially higher temperature than that at which the recycled gas exists when processing the heavy naphtha.
  • Product gas for recovery leaves separator 26 through line 29, passes through valve 3S and line 39 to cooler 38.
  • Liquid product passes from the bottom of separator 26 through line 30 through valve 36 and line 40 where it combines with the product gas and passes through cooler 38.
  • gas and liquid are cooled to conventional temperatures suc'h as 100 F. and then separated again in vessel 31.
  • Gas product leaves through line 33 and pressure control valve 31 and passes to a conventional gas recovery system.
  • Liquid product leaves separator 31 through line 32 and valve 42, which controls the level in separator 31, and passes to a conventional liquid stabilizing and rerunning system.
  • Boiling range (total naphtha), F 152-387 Naphthenes, vol. percent 43 Parans, vol. percent i 49 Aromatics, vol. percent 8 Bromine number 0.2 Sulfur, wt. percent 0.005 Octane number, CFRR 55.7
  • Catalyst composition 0.6 wt. percent Pt 0.6 Wt. percent Cl 98.8 wt. percent eta alumina Inlet temperature, F. 948 Pressure, p.s.i.g 420 Residence time, sec. 5.8
  • Recycle gas feed to reactor s.c.f./bbl. oil 6000 Density of recycle gas relative to air 0.25 Concentration of H2 in recycled gas, mol
  • Catalyst-Platinum or palladium suitably supported.
  • Inlet temperature F. 900-1000 Pressure, p.s.i.g 350-600 Residence time, sec 4 20 vRecycle gas feed to reactor, s.c.f./bb1.
  • Inlet temperature ⁇ F. 900-1000 Illressure, p-.s.i.g 50-300 Residence time, sec. 8-25 Recycle gas feed to reactor, .sl.c.f./bbl.
  • the present invention contemplates hydroforming anaphtha in the presence of a platinum Vgroupmetal catalyst disposed in a plurality of reactors in which the naphtha is hydroformed by passage through the said reactorsin series vunder hydroforming conditions of temperature, pressure and contact time.
  • a platinum Vgroupmetal catalyst disposed in a plurality of reactors in which the naphtha is hydroformed by passage through the said reactorsin series vunder hydroforming conditions of temperature, pressure and contact time.
  • the Anaphtha is separated into a ylight boiling fraction and a high boiling fraction and the separated fractions are separately hy'droformed.
  • the light naphtha is hydroformed under substantially -lower pressure than the heavy naphtha but in order to make full use of the heating and compres- ⁇ sor capacity the recycled gas fed to the reaction zone with the low boiling or light naphtha contains a higher percentage of hydrocarbons than does the recycled gas employed in the heavy naphtha. It is thus necessary to so operate the hydroforming of the .light naphtha that the recycled gas will contain at least 50% of the heat necessary to support the endothermic reaction of hydroforming.

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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)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Catalysts (AREA)
US555885A 1955-12-28 1955-12-28 Hydroforming process Expired - Lifetime US2902427A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE567544D BE567544A (enExample) 1955-12-28
US555885A US2902427A (en) 1955-12-28 1955-12-28 Hydroforming process
GB39287/56A GB798018A (en) 1955-12-28 1956-12-27 Improved hydroforming process
FR1169620D FR1169620A (fr) 1955-12-28 1956-12-28 Procédé d'hydroreformation
DEE13442A DE1038218B (de) 1955-12-28 1956-12-28 Hydroformierungsverfahren fuer Rohbenzin

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US555885A US2902427A (en) 1955-12-28 1955-12-28 Hydroforming process

Publications (1)

Publication Number Publication Date
US2902427A true US2902427A (en) 1959-09-01

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US555885A Expired - Lifetime US2902427A (en) 1955-12-28 1955-12-28 Hydroforming process

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US (1) US2902427A (enExample)
BE (1) BE567544A (enExample)
DE (1) DE1038218B (enExample)
FR (1) FR1169620A (enExample)
GB (1) GB798018A (enExample)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2251571A (en) * 1937-11-19 1941-08-05 Standard Oil Dev Co Catalytic treatment of hydrocarbons
US2380938A (en) * 1941-01-14 1945-08-07 Standard Oil Co Process of inhibiting cracking in re-forming of hydrocarbons
US2689208A (en) * 1951-01-31 1954-09-14 Universal Oil Prod Co Hydrocarbon conversion process
US2721884A (en) * 1955-10-25 Production of aromatic hydrocarbons

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2866745A (en) * 1951-12-15 1958-12-30 Houdry Process Corp Multistage hydrocarbon reforming process
NL92595C (enExample) * 1953-11-16

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721884A (en) * 1955-10-25 Production of aromatic hydrocarbons
US2251571A (en) * 1937-11-19 1941-08-05 Standard Oil Dev Co Catalytic treatment of hydrocarbons
US2380938A (en) * 1941-01-14 1945-08-07 Standard Oil Co Process of inhibiting cracking in re-forming of hydrocarbons
US2689208A (en) * 1951-01-31 1954-09-14 Universal Oil Prod Co Hydrocarbon conversion process

Also Published As

Publication number Publication date
FR1169620A (fr) 1958-12-31
BE567544A (enExample)
GB798018A (en) 1958-07-09
DE1038218B (de) 1958-09-04

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