US2510673A

US2510673A - Reforming gasoline

Info

Publication number: US2510673A
Application number: US789598A
Authority: US
Inventors: Annable Weldon Grant
Original assignee: Pure Oil Co
Current assignee: Pure Oil Co
Priority date: 1947-12-04
Filing date: 1947-12-04
Publication date: 1950-06-06
Anticipated expiration: 1967-06-06

Description

June 6, 1950, w. a. ANNABLE REFORMING GASOLINE Filed Dec. 4, 1947 QEZEUTW s H 1 L .l E

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(aim/m Patented June 6, 1950' I 7 V eldon G anth nnabl u elei l. I1 assi m n, Th .Bflxeflil; 09mm, hicago? ill; a. Q91.-

. n at nz trQhiq Application Dmemlgen 4, 191427; SerialzNo. 78.935798; .la m.-; 95 Q).

1'" 2 This inyentiomrelatesto a methoglffgr conver ingeasoline-Hadbns-Qfi owa tanemtingfio in oline of higheraoctane rating,

A 'ea h D $m 65 $:i1 0 IlQmiQ@ lY-E5 1? siblelto groclueegasplme b thermal craekihgo; arethermallm craekefd g-asolinesj samplets v e o m g; rations ayin an anenu-mber i rma e qm a; mal. fpx m qg bp" on; alqpreciably above 70 motor, method because? of; agd samples seven. and eight am s tpaiiglq 1m the excessive;losses reeulting WhGEhan' attemptis gasplinegl Table l\ /[ate rial:... n w. 1 2" Heavy'Fraction.

Motof octali'lqb uazena Value). ane N0 Actilal Mbtoi" ct Blendingwaluein parafiins-and naphthenes of heavy fraction; =1 e min slim eqctmeaula r ww ti efi la l m tewmw-k fiwfimk v made -to obtaim higher octane materials Itiswappanentimm the table thatzineveryin-v I have discovered thatdf gasoline ofi low oostance the: gasoline, contained. a largeportionofi tance number is properlyfractionatew to sepa heavy paxamnazand nanhthenesi of; low; octane rate. the portion which contains the hydrocar numben bons oflowoctanenumben, and thesewhydliocam accordance with, my invention gasolinet'is; loans are: separately: reformed, gasoline of high; 39 separated'into a light: and heavy. fgtaction and the Octane nu b app e a watalytieally heave inaet qn-,. i v contaipa a su-hetantia-li cracked or reformed gasoline can be prepaned amount of, arqmktticg, 1e s epa1;at.ed:,intov an a1:o@ with comparatively small 1OSS Of gasoline fracmaticaiebjmetion,ancka fraction rich in, panafr; tion: I w finaan hnanbthenes lowmeans ofrsolyent textnace Anhobjectnfgthe inventiqniiatoqpmvidea methro tion, extractive distillation, 012-: any: Qthen- Suitable; d for converting:lbwvctaneeasolinMntO 13 1?:m igate .fmmthe zstmctimqf; the lineof highen oc'tane number.v figaetignriseubjected;12.. thermal re ming Anothen objectofth sinyention is; to provide and tfr e nefq mate ia sepanate. into a he a method-J01: incre sing the; octane; number; .ofs a low boilin ydr carbpns without; excessive; lose: Q ant r am -rieh; iragtiomanga ma Q 1; 11: of'gasqlinflfionfitiwents Pa ami-naflthenee aml'vthe I2 fitill; othenohieetetqfi:tll dnvenfoioni wln hecQme: rritl i raet pa Q$ 1Mm emi e anna lemi txomfi ollow ng desecn ptim emit he IL. accompa yin dr meet; wlaieh; the sie efi unes Thus QJB P QQX QQ. w t mcese qn xthe 'is a; di rammatic; hqw n r a nagatus: i h i gg, 1W1: 9mm: numbe pamffine. m-

m;Gam ng;ou hein ent nn- 7 I ha v be n d scovered matthe: aw- 21mm number; rdi tment amhe. xaelsedsau ines 1e le-need y qoneen xat .1 A r a rtain Qar ffin mnann henesa Qt, 0w w ne E dme tim' teke t We m a a 'amall; umbenin, thQ=high- Q g=. fi0& i; thee line. The heayy fracfi oqni Q easq ine, na sxe tha ina i b il ng betme nia99mx a 1y 549- m .9? m x c mxztif fe n whene=-fx m30;%; m-fifififihe qt l gasq iyet ne mitswi m yeneeume te l m. ef min v.

r 22mm the Q en tes naphth m lierieee:

to a fractionating tower 3, after having been heated to a temperature sufficiently high to vaporize the gasoline fractions. The oil charged through line I may be straight run naphtha, cracked naphtha, or it may be crude oil containing naphtha fractions. The naphtha or other charging stock enters the fractionator 3 at a temperature of approximately 450-500 R, and is separated into a vapor overhead fraction boiling up to approximately 250-300 F. and a condensate having a boiling range of approximately 250-400 F. The vapor fraction is taken over= head through line 5 and condensed in condenser coil 1, and charged to gasoline storage tank 3. The heavy naphtha fraction boiling between approximately 250-400 F. is taken from the tower 3 as a side-stream through line H controlled by valve [3, and either charged by pump to sol= vent extractor I! or charged through line I9 con" trolled by valve 2| to a reformer charge tank 23. Residue may be withdrawn from tower 3 through line controlled by valve 21.

Whether the heavy condensate from tower 3 will be charged to the solvent extractor or to the reformer charge tank will depend on its content of aromatic hydrocarbons. Where the content of aromatics is low, as in the case of some straight run naphthas such as samples 7 and 8 of the previous table, the entire heavy naphtha fraction will be charged directly to the heavy naphtha charge tank. But where the aromatic content is relatively high, as in the case of cracked gasoline samples and the reformate shown in the foregoing table, the heavy fraction is charged to the solvent extractor where it is subjected to a conventional extraction with liquid sulfur dioxide, furfural, phenol or other known solvent for separating aromatics from parafiin and naphthene hydrocarbons in order to separate the naptha into two fractions, one of which is predominantly aromatic in nature, and the other of which consists chiefly of saturated hydrocarbons. The rafiinate, composed chiefly of saturated hydrocarbons, is withdrawn through line 29 and charged to the reformer charge tank 23. The extract passes to stripper 3| through line 33 wherein the solvent is separated from the extract composed chiefly of aromatic' and olefinic hydrocarbons. The solvent is recycled through line 35 to the extractor ll. Fresh solvent may be fed into the extractor ll through line 3'! controlled by valve 39. The extract after separation of solvent therefrom is charged from the stripper 3| through line 4| to gasoline storage tank 9.

Material from reformer charge tank is charged by pump 43 to reforming coil 45 Where the material may be subjected to temperatures of approximately 950-ll00 F. under super-atmospheric pressure ranging from approximately 200- 2,000 pounds per square inch. In the reforming coil the saturated hydrocarbons undergo conver sion to a high percentage of olefinic and aromatic hydrocarbons. From the reforming coil the conversion products pass through valve 4! Where pressure is partially reduced to fractionator 49. In the fractionator 49 the reformed products are fractionated into a low-boiling fraction having a boiling range up to approximately 250-300 R, which is taken from the tower as a condensate through line 5|, and sent through valve 53 to gasoline storage tank 9. A heavy condensate boiling between approximately 250 to 400 F. is taken from the tower as a side-stream through line 55 controlled by valve 57 and recycled to solvent extractor l1. Any heavy material formed in the reforming operation may be withdrawn from fractionator 43 through line 59 controlled by valve 61.. Gas formed in the reforming operation is withdrawn from fractionator 49 through line 63 controlled by valve 65.

Instead of using solvent extraction to separate aromatics from the saturated hydrocarbons in the heavy fraction, extractive distillation or azeotropic distillation may be used, as, for example, distillation with phenol or methyl alcohol.

As a specific example of the invention, gasoline from a high pressure thermal cracking operation have a motor octane number of 65.0. an initial boiling point of F., and an end point of 400 F., is separated into a light fraction boiling up to 250 F. and comprising 46.4% of the gasoline, and a heavy fraction boiling from 250- 400 F. comprising 53.6% of the total gasoline. The octane number of the low-boiling fraction is 72.4 and of the heavy fraction 529 motor method. The heavy fraction is solvent extracted with sulfur dioxide, producing a fraction rich in aromatics and olefins comprising 42% of the total, and having a motor octane blending number of approximately '76. The raffinate, comprising 58% of the heavy fraction, has an octane number of 23.0. Only the rafllnate portion of the gasoline is subjected to thermal reforming in a coil operated at a temperature of 1025 F. and a pressure of 700 pounds per square inch for a period of approximately 100 seconds. The product from the reforming operation is separated into a fraction boiling up to approximately 250 F., which is blended with the remaining fractions of the gasoline, and a fraction boiling between approximately 250-400 R, which is recycled to the sulfur dioxide extraction step. In this operation 92% of the initial gasoline is recovered as gasoline having a motor octane number of 75.0. The loss in gas and heavy products is approximately 8%.

It will be seen, therefore, that by separating from the reformer charging stock only those components which have low octane numbers and;

subjecting only these components to reforming, an over-all yield of approximately 92% of high octane gasoline with a suitable boiling range is,

corresponding approximately to a gasoline into.

two fractions, one having a boiling range up to about 300 F. and a second naphtha fraction boiling between about 300 and 400 F., (2) subjecting the said second fraction to a-thermal reforming operation, (3) separating the reformed products into a first fraction boiling up to about 300 F., and a second fraction boiling betweenabout 300 and 400 F.,- (4) separating the last" mentioned fraction into a fraction rich in arcmatics and olefins and another fraction rich in paraflinic and naphthenic hydrocarbons, (5)' subjecting the said paraffinic and naphthenic fraction to thermal reforming, (6) recovering therefrom a fraction boiling up to approximately 300 F. and a fraction boiling between about 300 and 400 F. rich in aromatics and olefins, and ('7) blending together as gasoline the fractions boiling up to about 300 F. and the fractions rich in' aromatics and olefins boiling between about 300 and 400 F.

2. Method in accordance with claim 1 in which the 300 to 400 F fraction rich in parafiinic and naphthenic hydrocarbons obtained in step (6) is recycled to the first mentioned thermal reforming operation identified as step (2) 3. Method in accordance with claim 1 in which the naphtha fraction boiling between about 300 and 400 F. obtained in step (1) is first separated 10 6 naphthenic hydrocarbons obtained in step (6) separated from the reformed products obtained in step (5) is recycled to the first mentioned thermal reforming operation identified as step (2).

WELDON GRANT ANNABLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,034,495 Sullivan Mar. 1'7, 1936 2,146,039 Whiteley Feb. 7, 1939 2,178,838 Kuhn Nov. '7, 1939 2,241,430 Snow May 13, 1941 2,324,295 Goldsby et a1 July 13, 1943

Claims

1. THE METHOD OF PREPARING GASOLINE OF HIGH OCTANE VALUE CONSISTING OF TH STEPS: (1) SEPARATING A NAPHTHA FRACTION HAVING A BOILING RANGE CORRESPONDING APPROXIMATELY TO A GASOLINE INTO TWO FRACTIONS, ONE HAVING A BOILING RANGE UP TO ABOUT 300*F. AND A SECOND NAPHTHA FRACTION BOILING BETWEEN ABOUT 300* AND 400*F., (2) SUBJECTING THE SAID SECOND FRACTION TO A THERMAL REFORMING OPERATION, (3) SEPARATING THE REFORMED PRODUCTS INTO A FIRST FRACTION BOILING UP TO ABOUT 300*F., AND A SECOND FRACTION BOILING BETWEEN ABOUT 300* AND 400*F., (4) SEPARATING THE LAST MENTIONED FRACTION INTO A FRACTION RICH IN AROMATICS AND OLEFINS AND ANOTHER FRACTION RICH IN PARAFFINIC AND NAPHTHENIC HYDROCARBONS, (5) SUBJECTING THE SAID PARAFFINIC AND NAPHTHENIC FRACTION TO THERMAL REFORMING, (6) RECOVERING THEREFROM A FRACTION BOILING UP TO APPROXIMATELY 300*F. AND A FRACTION BOILING BETWEEN ABOUT 300* AND 400*F. RICH IN AROMATICS AND OLEFINS, AND (7) BLENDING TOGETHER AS GASOLINE THE FRACTIONS RICH IN AROMATICS AND OLEFINS BOILING BETWEEN ABOUT 300* AND 400*F.