US2958718A - Upgrading catalytic c5 hydrocarbons - Google Patents

Upgrading catalytic c5 hydrocarbons Download PDF

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US2958718A
US2958718A US629508A US62950856A US2958718A US 2958718 A US2958718 A US 2958718A US 629508 A US629508 A US 629508A US 62950856 A US62950856 A US 62950856A US 2958718 A US2958718 A US 2958718A
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pentene
hydrogenation
hydrocarbons
feed
methylbutene
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US629508A
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Donald L Baeder
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ExxonMobil Technology and Engineering Co
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Exxon Research and Engineering Co
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/12—Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers
    • C07C7/13—Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers by molecular-sieve technique
    • 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
    • C10G25/00—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
    • C10G25/02—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents with ion-exchange material
    • C10G25/03—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents with ion-exchange material with crystalline alumino-silicates, e.g. molecular sieves

Definitions

  • the over-all octane rating of the fuel is some fraction through a molecular sieve adsorption zone so as to remove therefrom substantially all the normal hydrocarbons.
  • a typical composition is as follows:'
  • the molecular sieves utilized are known.
  • the scientific and patent literature contains numerous references to the sieving action of natural and synthetic zeolites.
  • natural zeolites having this sieving property may be mentioned chabazites.
  • a synthetic zeolite with molecular sieve properties is described in US. Patent 2,424,191.
  • Zeolites vary somewhat in composition but generally contain the elements silicon, aluminum, and oxygen as well as an alkali metal and/or an alkaline earth metal element, e.g., sodium and/0r calcium.
  • the naturally occurring zeolite, analcite, for instance, has the empirical formula NaAlSi- O .H O. Barrer, U.S.
  • Patent 2,306,610 teaches that all or part of the sodium is replaceable by calcium to yield, on dehydration, a molecular sieve having the formula (Ca.Na Al Si O Black, US. Patent 2,522,426, describes a synthetic molecular sieve zeolite having the formula 4CaO.A1 'O .4SiO
  • a large number of other naturally occurring zeolites having molecular sieve activity i.e., the ability to adsorb straight chain hydrocarbons and exclude the branch chain isomers due to differences in molecular size, are known.
  • the pores in different zeolites may vary in diameter from less than 3 or 4 to 15 'or more Angstrom units, but for any one zeolite the pores are substantially of uniform size. It is preferred to use zeolites having pore openings of about 5 Angstroms, e.g., calcium alumino silicates.
  • the molecular sieve contacting operation is carried out in the vaporphase at 250 to 350 F. depending on boiling point of feed.
  • The. v./l1r./v. is about 0.5 to 1.
  • the operation is continued until the sieve is saturated with adsorbate (about 10-12 wt. percent on sieve).
  • the adsorbate can be removed by a selective desorbent such as propylene which is then separated from the adsorbent by'simple distillation. It can also be removed by raising the sieve temperature to 600 F. and lowering the pressure to 50 mm.
  • Thefir'sttech nique is preferred since at 600 F.”some polymerization of n-olefins can occur.
  • This effluent is then hydrogenated for complete saturaof hydrogenation catalysts m ay'beemployed. Preferred tion over a hydrogenation catalyst.
  • a wide variety catalysts constitute the oxides of cobalt or molybd Patented Nov. 1, 1.960.
  • cobalt molybdate in admixture and including cobalt molybdate.
  • Other catalytic agents which can be used are platinum or nickel.
  • these catalytic agents are supported on an adsorbent support such as alumina. It is particularly preferred to employ cobalt molybdate as the catalyst.
  • the pressure employed is to be in the range of 25 to 500 pounds per square inch although it is preferred to use pressures below 400 p.s.i.g. for the hydrogenation of the efiluent and it is particularly desirable to employ a pressure of about 200 p.s.i.g. Throughputs of 1 to 2 v./v./hr. may be employed although the preferred range is about 5 to v./v./hr.
  • the temperature maintained during hydrogenation is about 500 to 800 F. and specifically 700 F. Contact of the efliuent with the catalyst under these conditions should be carried out employing a rate of hydrogen supply above about 1000 standard cubic feet of hydrogen per barrel, and generally about 2500 standard cubic feet
  • the specific hydrogenation conditions are to be selected from the foregoing limits by regard to the resulting olefin saturation and/or hydrogen consumption.
  • hydrogen consumptions of about 450 to 600 standard cubic feet per barrel will be employed.
  • a hydrogen consumption of at least about 500 s.c.f./b. is ordinarily required.
  • a Baytown catalytic C feed is fed through line 1 to a 5 Angstrom molecular sieve adsorption zone 2.
  • the adsorbent may be arranged on trays or packed therein with or without supports. One adsorption zone has been shown for simplicity, but two or more can be used.
  • the feed is at a temperature of 250 F. in the vapor phase and the flow rate is 0.5 v./v./hr.
  • the feed had an initial Research octane number of 102.2 and a motor octane number of 88.3. Substantially all, e.g., 31 volume percent on feed of the normal hydrocarbons are adsorbed on the adsorbent in zone 2.
  • the efiiuent free of normal hydrocarbons, is withdrawn from adsorption zone 2 through line 5 to hydrogenation zone 6.
  • This efiiuent prior to the hydrogenation has a Research octane number of 103.5 and a motor octane number of 95.
  • the efliuent is hydrogenated at a temperature of 700 F. in the vapor phase over a cobalt molybdate on alumina catalyst. This efiluent which contains about 38.5 vol. percent olefins is thus completely saturated.
  • the conditions in hydrogenation zone 6 are a pressure of 200 p.s.i.g., a throughput of 2 v./hr./v.
  • the adsorbate on the molecular sieve is desorbed by the addition of propylene also at 250 F. Feed rate is 0.5 v./hr./v.
  • the adsorbate is separated from the propylene by simple distillation and contains the following materials in the indicated yields.
  • Adsorbate Yield on feed n-Pentane 5.0
  • This adsorbate is about 75% olefinic and can be utilized as a feed for chemicals. Because of the normal character of the olefins they are excellent feeds for making alcohols, aldehydes, ethers and therefore command a high price.
  • a process for upgrading a catalytic C hydrocarbon fraction containing isopentane, n-pentane, Z-methylbutene-l, pentene-l, cis-pentene-2, trans-pentene-Z, and 2-methylbutene-2 which comprises the steps of passing the fraction through a molecular sieve adsorption zone so as to remove therefrom substantially all the normal hydrocarbons n-pentane, pentene-l cis-pentene-2 and trans-pentene-Z; withdrawing the normal hydrocarbonfree efiluent from the adsorption zone and hydrogenating the effluent for complete saturation of the Z-methylbutene- 1 and the 2-methylbutene-2 therein in the presence of a hydrogenation catalyst.

Description

Nov. 1, 1960 o. L. BAEDER UPGRADING CATALYTIC c HYDROCARBONS Filed Dec. 20, 1956 Donald L. Baedel Inventor By K CW Afiorney United States Patent 2,958,718 UPGRADING CATALYTIC C HYDROCARBONS Donald L. Baeder, Fanwood, 'N.J., assignor to Esso Research and Engineering Company, a corporationof Delaware Filed Dec. 20,- 1956, Ser. No. 629,508 6 Claims. (Cl. zen-683:9
pression ratio. At the present time the compression ratio of current automobile engines has been increased to values above 6.5, ranging upwardly to as high as 12. Engines having such high compression ratios require use of high anti knock gasolines. The more extended use of automatic transmissions has also aggravated the problem of satisfying the octane requirements of current automotive engines. In the past, octane ratings of gasolines have primarily been determined by ASTM test, designated D908-47T. vWhile this is an important and valuable anti-knock rating test, it has'become appreciated that the Research octane rating of a gasoline as determined by this method correlates poorly with actual road performance of a gasoline. This is true in part since the Research octane number is determined in a test pro cedure at which the engine is operated at conditions of constant speed and constant load. As opposed to this, the actual knocking tendency of a fuel in road performance is greatest during maximum load. It is therefore appreciated at this time that the Research octane number rating of a gasoline is not a complete indication of the value of a gasoline in satisfying an engine under road conditions.
i As a result, other methods of determining octane ratings are commonly employed. One such method is the so-called motor method test, designated by ASTM test Method D357-47. It has been found that the motor method octane determination correlates with the road performance of a gasoline somewhat better than the Research octane rating.
;In view of these basic factors, production of present day high quality gasolines must be carried out with reference to both the Research and Motor method octane rating. The over-all octane rating of the fuel is some fraction through a molecular sieve adsorption zone so as to remove therefrom substantially all the normal hydrocarbons. The normal hydrocarbon-free effluent from the tained from conventional catalytic cracking of petroleum g'as oils; This fraction typically boils in ,the'range of 75 3 to 115.F. and 'contains's'ome C s. A typical composition is as follows:'
Analysis of typicdllliayt own) catalytic C5 stream Vol. percent Butanes V 0.6 Butenes 2.6 Isopentane 42.2 n-Pent-ane 5.0 =2-methylbutene-1 11.6 Pentene-fl 7.6 Cis-pentefie-Z 5.8 tnans-pentene-2 9.2 2-methylbutene-2 15.0 Pentadienes 0.4
The molecular sieves utilized are known. The scientific and patent literature contains numerous references to the sieving action of natural and synthetic zeolites. Among the natural zeolites having this sieving property may be mentioned chabazites. A synthetic zeolite with molecular sieve properties is described in US. Patent 2,424,191. Zeolites vary somewhat in composition but generally contain the elements silicon, aluminum, and oxygen as well as an alkali metal and/or an alkaline earth metal element, e.g., sodium and/0r calcium. The naturally occurring zeolite, analcite, for instance, has the empirical formula NaAlSi- O .H O. Barrer, U.S. Patent 2,306,610, teaches that all or part of the sodium is replaceable by calcium to yield, on dehydration, a molecular sieve having the formula (Ca.Na Al Si O Black, US. Patent 2,522,426, describes a synthetic molecular sieve zeolite having the formula 4CaO.A1 'O .4SiO A large number of other naturally occurring zeolites having molecular sieve activity, i.e., the ability to adsorb straight chain hydrocarbons and exclude the branch chain isomers due to differences in molecular size, are known. The pores in different zeolites may vary in diameter from less than 3 or 4 to 15 'or more Angstrom units, but for any one zeolite the pores are substantially of uniform size. It is preferred to use zeolites having pore openings of about 5 Angstroms, e.g., calcium alumino silicates.
In general the molecular sieve contacting operation is carried out in the vaporphase at 250 to 350 F. depending on boiling point of feed. The. v./l1r./v. is about 0.5 to 1. The operation is continued until the sieve is saturated with adsorbate (about 10-12 wt. percent on sieve). The adsorbate can be removed by a selective desorbent such as propylene which is then separated from the adsorbent by'simple distillation. It can also be removed by raising the sieve temperature to 600 F. and lowering the pressure to 50 mm. Thefir'sttech nique is preferred since at 600 F."some polymerization of n-olefins can occur. x
i The contacting of the, feed with the molecular sieve in the adsorptbn zone is conducted so as to remove frOmthe feed substantially all (95 to 98 ,wt. percent) the normal hydrocarbons. v t
The normal hydrocarbon-free ,eflluent is withdrawn.
' This effluent is then hydrogenated for complete saturaof hydrogenation catalysts m ay'beemployed. Preferred tion over a hydrogenation catalyst.
In, conducting the hydrogenation of the eflluent fraction in accordance with this invention, a wide variety catalysts constitute the oxides of cobalt or molybd Patented Nov. 1, 1.960.
in admixture and including cobalt molybdate. Other catalytic agents which can be used are platinum or nickel. Preferably these catalytic agents are supported on an adsorbent support such as alumina. It is particularly preferred to employ cobalt molybdate as the catalyst. The pressure employed is to be in the range of 25 to 500 pounds per square inch although it is preferred to use pressures below 400 p.s.i.g. for the hydrogenation of the efiluent and it is particularly desirable to employ a pressure of about 200 p.s.i.g. Throughputs of 1 to 2 v./v./hr. may be employed although the preferred range is about 5 to v./v./hr. The temperature maintained during hydrogenation is about 500 to 800 F. and specifically 700 F. Contact of the efliuent with the catalyst under these conditions should be carried out employing a rate of hydrogen supply above about 1000 standard cubic feet of hydrogen per barrel, and generally about 2500 standard cubic feet per barrel.
The specific hydrogenation conditions are to be selected from the foregoing limits by regard to the resulting olefin saturation and/or hydrogen consumption. In general, for hydrogenation for complete saturation, hydrogen consumptions of about 450 to 600 standard cubic feet per barrel will be employed. In treating a typical effluent for complete olefin saturation, a hydrogen consumption of at least about 500 s.c.f./b. is ordinarily required.
The advantages of this invention will be better understood by reference to the following example and flow diagram.
Referring now to the flow diagram, a Baytown catalytic C feed is fed through line 1 to a 5 Angstrom molecular sieve adsorption zone 2. The adsorbent may be arranged on trays or packed therein with or without supports. One adsorption zone has been shown for simplicity, but two or more can be used. The feed is at a temperature of 250 F. in the vapor phase and the flow rate is 0.5 v./v./hr. The feed had an initial Research octane number of 102.2 and a motor octane number of 88.3. Substantially all, e.g., 31 volume percent on feed of the normal hydrocarbons are adsorbed on the adsorbent in zone 2.
The efiiuent, free of normal hydrocarbons, is withdrawn from adsorption zone 2 through line 5 to hydrogenation zone 6. This efiiuent prior to the hydrogenation has a Research octane number of 103.5 and a motor octane number of 95. In hydrogenation zone 6 the efliuent is hydrogenated at a temperature of 700 F. in the vapor phase over a cobalt molybdate on alumina catalyst. This efiluent which contains about 38.5 vol. percent olefins is thus completely saturated. The conditions in hydrogenation zone 6 are a pressure of 200 p.s.i.g., a throughput of 2 v./hr./v. with a hydrogen consumption of about 150 s.c.f./b. The hydrogenated efiluent is withdrawn through line 7 at a 70% yield on original total C feed. Its Research octane number is 104.2 and its motor octane number is 100.0. This latter figure represents a marked increase.
The adsorbate on the molecular sieve is desorbed by the addition of propylene also at 250 F. Feed rate is 0.5 v./hr./v. The adsorbate is separated from the propylene by simple distillation and contains the following materials in the indicated yields.
Adsorbate: Yield on feed n-Pentane 5.0
n-Pentene-l 7.6 Cis Pentene-Z 5.8
Transpentene-Z 9.2 Pentadiene 0.4 C438 3.2
This adsorbate is about 75% olefinic and can be utilized as a feed for chemicals. Because of the normal character of the olefins they are excellent feeds for making alcohols, aldehydes, ethers and therefore command a high price.
The advantages of this invention will be apparent to the skilled in the art. A significant motor octane number improvement is obtained without the necessity of hydrogenating the total feed. Further, hydrogenation of the total feed would not produce a gasoline blending stock with both high Research and Motor octane number. This is due to the fact that the Research octane number of normal olefins are degraded on hydrogenation. The motor octane number in only slightly improved. This is shown as follows:
Research +8 ml. TEL
n-pentane 83. 6
Since all of the C olefins in the adsorbate (31% on feed) would be converted to n-pentane, it is obvious that the octane number obtained by hydrogenation of the total C feed would be inferior to the octane obtained by selective separation fol-lowed by hydrogenation of the isop arafiinisoolefin fraction. Thus this octane improvement is obtained with marked efiiciencies in hydrogen use and equipment size.
It is to be understood that this invention is not limited to the specific examples which have been ofiered merely as illustrations and that modifications may be made without departing from the spirit of the invention.
What is claimed is:
1. A process for upgrading a catalytic C hydrocarbon fraction containing isopentane, n-pentane, Z-methylbutene-l, pentene-l, cis-pentene-2, trans-pentene-Z, and 2-methylbutene-2, which comprises the steps of passing the fraction through a molecular sieve adsorption zone so as to remove therefrom substantially all the normal hydrocarbons n-pentane, pentene-l cis-pentene-2 and trans-pentene-Z; withdrawing the normal hydrocarbonfree efiluent from the adsorption zone and hydrogenating the effluent for complete saturation of the Z-methylbutene- 1 and the 2-methylbutene-2 therein in the presence of a hydrogenation catalyst.
2. The process of claim 1 in which the molecular sieve has p'ore openings of about 5 Angstroms.
3. The process of claim 2 in which the molecular sieve contacting step is carried out in the vapor phase at a temperature in the range of 250 to 350 F. and a feed rate of 0.5/l v./v./hr.
4. The process of claim 3 in which the C hydrocarbon fraction has a boiling point in the range of 75 to F.
5. The process of claim 4 including the additional step of desorbing the normal hydrocarbons from the sieve by treatment with propylene.
6. The process of claim 2 in which the molecular sieve is a calcium alumino silicate.
References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Brooks et al.; The Chemistry of Petroleum Hydrocarbon, vol. 3, pages 121 and 331-2, May 16, 1955.
Nelson et al.: Analytical Chemistry, vol. 29, pages 1026- 1029, July 1957.

Claims (1)

1. A PROCESS FOR UPGRADING A CATALYTIC C5 HYDROCARBON FRACTION CONTAINING ISOPENTANE, N-PENTANE, 2-METHYLBUTENE-1, PENTENE-1, CIS-PENTENE-2, TRANS-PENTENE-2, AND 2-METHYLBUTENE-2, WHICH COMPRISES THE STEPS OF PASSING THE FRACTION THROUGH A MOLECULAR SIEVE ADSORPTION ZONE SO AS TO REMOVE THEREFROM SUBSTANTIALLY ALL THE NORMAL HYDROCARBONS N-PENTANE, PENTENE-1 CIS-PENTENE-2 AND TRANS-PENTENE-2, WITHDRAWING THE NORMAL HYDROCARBONFREE EFFLUENT FROM THE ADSORPTION ZONE AND HYDROGENATING THE EFFLUENT FOR COMPLETE SATURATION OF THE 2-METHYLBUTENE1 AND THE 2-METHYLBUTENE-2 THEREIN IN THE PRESENCE OF A HYDROGENATION CATALYST.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2306610A (en) * 1941-02-24 1942-12-29 Barrer Richard Maling Fractionation of mixtures of hydrocarbons
US2357741A (en) * 1940-10-28 1944-09-05 Anglo Iranian Oil Co Ltd Production of gasolines
US2360253A (en) * 1939-10-23 1944-10-10 Standard Oil Co Process for producing motor fuel
US2420030A (en) * 1943-04-13 1947-05-06 Standard Oil Dev Co Motor fuels and preparation thereof
US2810004A (en) * 1955-03-01 1957-10-15 Exxon Research Engineering Co Hydrogenation of catalytic naphthas
US2818455A (en) * 1955-03-28 1957-12-31 Texas Co Desorption of straight chain hydrocarbons from selective adsorbents

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2360253A (en) * 1939-10-23 1944-10-10 Standard Oil Co Process for producing motor fuel
US2357741A (en) * 1940-10-28 1944-09-05 Anglo Iranian Oil Co Ltd Production of gasolines
US2306610A (en) * 1941-02-24 1942-12-29 Barrer Richard Maling Fractionation of mixtures of hydrocarbons
US2420030A (en) * 1943-04-13 1947-05-06 Standard Oil Dev Co Motor fuels and preparation thereof
US2810004A (en) * 1955-03-01 1957-10-15 Exxon Research Engineering Co Hydrogenation of catalytic naphthas
US2818455A (en) * 1955-03-28 1957-12-31 Texas Co Desorption of straight chain hydrocarbons from selective adsorbents

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