US 2944959 A
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July 12, 1960 R. E. KLINE ETAL 2,944,959
PRocEss FOR UPGRADING A WIDE RANGE cAsoLINE Filed Feb. 26, 1958 F.nZ' @www dffORA/EY 'hi'gh octane rating.
straight run and cracked gasolines.
` nited Sites 4PRocEss FORUPGRADIN'G A WIDE RANGE GAsoLlNE Filed Feb. 26, 195s, ser. No. 717,692
5 Claims ,(Cl.- 20.8.-79)
This invention relates to a process for improving the value of gasoline fractions and more particularly to-a process'comprising separation of gasoline range hydrocarfbons into fractions and-selective treatment of suchff'ractions. and-blending of products to obtain motor fuels of The improvement ofgasoline octane ratingsis a matter of great'importance to petroleum refiners. In the past, gasolines have been producedby catalytically reforming a relatively narrow range straight run fraction and blending -the reformate with other relatively high octane-fractions suchV as catalytically cracked gasoline. Normally, the narrow gasolinerange fraction is processed a single type of reforming process that results chiefly in increased aromatic content of the fraction.
There has existed for some time a need fora unified system of treatments for upgrading the entire pool of straight run` gasoline and/or'olefinic gasolinas, such as catalytically or thermally cracked ,gasolines We have now developed a combination process for treating the entire refinery pool of gasoline range hydrocarbons whether it consist solely of straight run gasoline or of Our process is characterized by the separation of a full range gasoline fraction into smaller fractions that are amenable to particular treatments, each of theseselected treatments .cooperating in a unique way with the treatments of other fractions.
In general, our process comprises fractionating a full range straight run gasoline fraction to obtain a light paraffinic fraction containing substantially all of the C5and CB parafns of the charge stockra middle fraction including the C7 hydrocarbons and extending to an end point of about 360 F. anda heavy fraction having an initial boiling point of about 360 1:".y n-Pentane and n-heXane of the-light parainic fraction are subjected to'isomerization bycontact with a supported platinum catalyst at a `temperaturefrom 600 to 850 F., a liquidhourly space 'velocity greater than 5 volumes of hydrocarbon pervolurne of catalyst per hour (hereinafter abbreviated vol./,
v,o1./.hr.v)",and a low hydrogen4 concentration o f below about 1000 standard cubic feet'per barrel of hydrocarbon (hereinafter abbreviated scf/bbl.) and a product of'increased branched chain parafncontentis recovered. The middle fraction is reformed by contact with aplatinum-alumina catalyst at a hydrogen concentration greater than 3000 s.c.f./bbl., a space velocity below 4 VvoL/vol/ hr., and a temperature yabove 850 F. and a reformate of increased aromatics content is recovered. ,The heavy gasoline fraction is subjected to hydroreforrning in the presence of a fluidized molybdenum oxide catalyst at a hydrogen concentration greater than 3000 sci/bbl., a temperature about 850 F. and a space velocitybelow 3 vol./vol./hr. and two products are recovered, a gasoline of lower average molecular weight and higher aromatic content than the charge to the fluid catalytic hydroreforming treatment and -a heavier residualproduct. The gasoline range products of each of'the three catalytic nent treatments are then blended to produce a gasoline product lboiling from about 100 to 400 F., and having an un-l leaded Research method octane rating of about or above. i
lOur process can be applied to the treatment of the entire refinery gasoline pool, including straight run gasolines and oleiinic gasolines obtained from cracking processes and the like. In this event the process will include the procedure of fractionating a full range (e.g., C5- 450 F.) olenic gasoline to obtain a light fraction and at least o ne heavier fraction. The light fraction contain- 'ing C5 and C6 hydrocarbons is blended without further treatment with the gasoline product obtained by treatment of straight run gasoline. A heavier fraction is mixed with the heavy straight run fraction charged to the fluid catalytic hydroreforming stage. lnan especially preferred embodiment an intermediate fraction of the olenic gasoline is subjected to a mild refining treatment comprising contactwith a hydrogenating catalyst at a temperature below 750 F. a space velocity from 3 to l0 vol./Vol./hr.,
and ahydrogen concentration from 500 to 2000 s.e.f./
bbl. Vwhereby to saturate the olefins and reduce the sulfur Vcontent of the fraction. The resulting product is then mixed with the straight run feed stock for platinum-catalyst fixed-bed reforming.
' `Our process will be described in more detail by reference to the drawings, of which:
Figure l is a flow diagram of one embodiment Vof our process in which the feed stock comprises full range straight run and olefinic gasoline.
Figure 2 is a ow diagram of a modification of our process inthe charging of olefinic gasoline.
`In the modification of our process indicated by the ow diagram of Figure 1 the charge stock comprises full 4range straight run gasoline and olefinic gasoline which range in composition from C5 hydrocarbons to 450 F. end point material. The straight run gasolinefeedv stock is' y introduced by line 10 to a vfractionating column 11, which is a standard multidraw bubble tray fractionating column. Three products are withdrawn from column 11: an overhead light gasoline lfraction consisting of C5 Aand C6 hydrocarbons; a middle fraction consisting of C7 hydrocarbons to 360 F. end point material; and a heavy Yfraction boiling from about 360 to 450 F. The light `fraction is passed by line 12 to a second fractionating ycolumn 13 in Which isopentane is separated from npentane and the hexanes. Isopentane is withdrawn overhead by line 14 and is recovered for blending with the final p roduct. The bottoms from column 13, consisting of n-pentane, n-hexane and branched chain hexanes, is
tion reactor `19 is treated under hydroisomerization conditions described in the patent application of William C.
`Srtarnesand Robert C. Zabor, Serial No. 508,980 filed VMay 17, 1955, now U.S. Patent 2,831,908.
Typical hydroisomerization conditions for the reactor 19 include van average reactor temperature of about 800 F., pressure of about 500 pounds per square inch gauge (hereinafter abbreviated as p.s.i.g.), a liquid-hourly space velocity of about 8 volumes of hydrocarbon per volume of catalyst per hour and a hydrogen concentration of about 500 standard cubic feet per barrel of hydrocarbon. 'Ihe catalyst in this embodiment consists essentially of about 0.5 weight percent platinum, 1.0 weight percent liuorine and the balance predominantly alumina. A
.product rich. in branched chain C5 and C6 parafiins is recovered from reactor 19 by line 20. Hydrogen isseparated from the hydrocarbon product and is recycled to the reactor feed in advance of the preheater. The high octane hydrocarbon product, after stabilization and fractionation is recovered for blending to form the nal gasoline product. Y
The composition of the middle fraction withdrawn from column 11 ranges in this specific embodiment from C,
The catalytic contact in reactor 23is carried out at lowerV space velocity, higher hydrogen concentration and higher temperature than the contact in reactor 19. The space velocity of the feed to reactor 23 is from l to L4 volumes of hydrocarbon per volume of catalyst per hour. The hydrogen concentration is above 3000 s.c.f./bbl. and the reactor inlet temperature is about 900 F. The drawing, for simplicity, shows a single reactor 23.for the reforming of the middle fraction over a fixed-bed platinum-alumina catalyst. However, as we will explain more fully hereinafter, this reforming stage can be carried out in a series of two or more reactors, each having la preheater. Y
The eluent from reactor 23 is Withdrawn via line 24. The normally liquid hydrocarbons are separated from hydrogen and light hydrocarbon gases by conventional means not shown in the drawing and hydrogen is recycled to the charge in advance of the preheater 22. The entire normally liquid hydrocarbon product is of the gasoline boiling range, i.e., end point no higher than about 400 F. It is a high octane product of about the same average molecularV weight but of higher aromatic content than the middle fraction charged to the reactor 23 and without further fractionation can be blendedin its entirety with the Iinal gasoline product withdrawn Yvia line 32.
The heavy fraction withdrawn from column 11 via line 25 is the residue of the vstraight run gasoline feed stock boiling above about 360 F. This heavy fraction, after being mixed with hydrogen, from line 26 andpreheated in the heater 27 is introduced to the uid catalytic hydroreforming reactor 2S. `The reactor 28 contains a fluidized bed of nely divided catalyst consisting of molybdenum oxide supported on alumina. Reactionconditions include: temperature 950 F., pressure 500 p.s.i.g., liquid-hourly space velocity l vol./vol./hr. and hydrogen concentration 6,000 s.c.f./bbl. Reactor 28 has. associated with it a catalyst regeneration vessel, notcshown in the drawing through which the spent iluidized catalyst from the reactor is continuously circulated. The catalyst is regenerated by combustion and a stream Vof hot regenerated catalyst is continuously returned to reactor 28 in a manner well known in the art. A reformed product of substantially lower average molecular weight and higher octane number than the heavy fraction charged is Withdrawn overhead from reactor 28. After separation of the normally liquid hydrocarbons from light. hydrocarbons and hydrogen, the latter being recycled to the reactor in advance of the preheater, the heavy fraction reformate is introduced to the fractionating column 29. A high octane gasoline overhead product is recovered via line 30 for blending to form the nal gasoline product. The bottoms, which boils above about 400 F. is passed to fuel oil blending via line 31.
The gasoline product Withdrawn by line 32 is a blend of the entire normally liquid hydrocarbon content of the isomerate and ,straight run isopentane from line. 313, the
`entire normally liquid hydrocarbon content of the tixed- 'bed platinum catalyst reformate .from line 24 and the light fraction of the -uid catalytic reformate from line 30. The blend has a leaded octane rating (Research, +3 cc.
TEL/gal.) of above and a boiling range from about to 400 F.
The particular embodiment-.of our process that we have described with reference to the drawings can be varied somewhat. We will now discuss ways in which the process can be varied Without depart-ing from the spirit of the invention; Y
We have disclosed. separating straight run gasoline into three fractionsfa C5-C6 fraction, a C7360 F. fraction and a 360 F. toend point fraction. An essential fea- .ture of our invention is that the C5 and C6 parains are separated fromhigher boiling components and are upgraded by hydroisomerization rather than by reforming las applied to ,the-A higher boiling fractions. [Since the light fraction contains almost ,all of the C5 and C6 paraftins,l the lightest'coinponents of the middle fraction are the-C7 hydrocarbons. The `middle fraction, within the practical limits of refinery separa-tion, is substantially free of hexaucs andlighter components. VThe middle frac- Ltion, `in accordance 4:with the invention, isreformed over a 4iixedabed platinum-alumina catalyst. An important feature of our invention is that .the charge to this stage contains only components for which this type of reforming .is particularly suited. It contains no more than minor yand harmless amounts of components, such as oleiins, sulfur compounds or high boiling hydrocarbons, that would rapidly inactivate the fixed-'bed platinum cat-alyst if present in sufficiently high concentrations. Preferably, the end point of the middle fraction is about 360 F. Satisfactory results can be obtained with a middle fraction having an end point somewhat lower than 360 F., for example, as low as 320 F. However, the end poi-nt of the middle fraction must not be substantially above 3609 -F. The reason is that naphthenes of the middle vfraction are dehydrogenated to aromatics in the xed-bed reforming stage. The reformate therefore has a higher end point than the reforming charge stock.
If the end point of the middle fraction which is the retor-ming charge stock is much above 360 F. the end point of the reformate will be too high for gasoline blending. Therefore, it would be necessary to refractionate the reformate to obtain a fraction suitable for gasoline blending. An advantage of our process is that .the
reactor, efduent from Athe fixed-bed reforming stage, after being separated from light gases, can be passed directly to final gasoline product blending without further fractionation.
The heavy fraction from the distillation of the straight run gasoline comprises al1 material boiling above the end point of .the middle fraction. Therefore, the initial point of the heavier fraction is preferably about 360 F. but can vary from about Y320 F. .to 360 F. ,A significant feature of the heavy fraction is that it contains materials that would not be satisfactory for charging to a fixed-bed platinum catalyst Vreformingprocess .but which can be satisfactorily treated in tiuid catalytic reforming. For convenience,we have referred to the heavy fraction as a 450. end-point fraction .and this is the preferred end point. However, in v.accordance -w-ith our invention the heavy lfractions can range in end point from about 410 to 500 F. f
We have described one-particular combination of reaction conditions for the `hydroisorneriz-ation of .the light straight .run fraction. However, as already mentioned, other conditions within the ranges of hydroisomerization conditions described in said patent application Serial No. 508,980, now U.S. Patent 2,831,908, can be used. These conditions include, in-cornparisonto catalytic reforming conditions, a low hydro-gen concentration, a high space velocity vand a moderate temperature.
'I'helhydroisomerization; process employing this-com- 5 bination'of condi-tions is particularly adapted for charge stocks highly concentrated in valiphatic pentanes and hexanes (i.e., containing `at least 85 volume percent aliphatic pentanes .and/or hexanes) and is characterized in its results by a high space-time-yield of the desired `branched chain parains. The hydrogen concentration much lower than is used in .catalytic reforming of highly naphthenic stocks, namely, 4below about 1000 scf/bbl. However, the hydrogen concentrationmust be appreciable. 'If it is 'toorlow the catalyst ,will be rapidly deactivated-by canbonaceous deposits. Therefore, the hydro-gen concentration'islessthan'about 1000 s.c.f./ bbl. .but greater than'theconcentration'corresponding to rapid catalyst 'deactivation and' in nany `event 4'greater than about 50 s.c.f./bb1.
The liquid-honrly space velocity is at least 5 vol./vol./ hr. and preferably is V:at least V8 vol./vol./hr. With the 1high rate of isomeriaation 'obtained with the `stated `low hydrogen concentration, satisfactory conversion 'to branched chain isomers can be obtained at very high space velocity, -e.g., 25 voL/voL/hr. or higher. The average reactor tempera-ture in the hydro'isomerization stage is considerably below conventional temperatures for catalytic refonmfing and will in noevent be higher than 850 F. The exact Ytemperature will depend o-n the particular charge stock and on the activity of the particular yjgilatinurn-alumina catalyst. A highly active catalyst, promoted with a high concentration of uorine, will give (satisfactory conversions at temperatures as low as about `600 F. Accordingly, the temperature can range from 600 to 850 F. The reactor pressure should be above about 200 p.s.i.g. and lprefer-ably is 200 to 600 p.s.i.g.
The platinum-alumina catalyst for' the hydroisomerization stage comprises a minor amount of platinum and a fmajor amount of alumina. The catalyst can be in the 4form of irregular granules or of particles of uniform size rand shape prepared by pelleting, extrusion or other suitablemethods. The platinum content can be from 0.1 to 5 percent by weight butpreferably is from 0.3 to 0.6 percent by weight. The catalyst contains a minor amount, -for example, from 0.1 to l percent by weight of chlorine `and/ or fluorine and/ or other activating components. The halogen or other activating components can also be included in the feed to the process. VThe catalyst may conltain a minor amount, for example, percent vor less, of
.silica which serves as a stabilizer.
, Figure 1 shows an embodiment of our process in which the C5 and C6 fraction is distilled to remove isopentane,
,after which the rest of the fraction, consisting of n-pentane,
[,nrhexa'ne and the branched chain hexanes, is charged to lthe hydroisomerization stage'. However, a number of variations are possible in processing the C5 and C6 partaffins. The essential step is that n-pentane and n-hexane are hydroisomerized in contact with a platinum-alumina `catalyst under the described reaction conditions, but it is not essential that'they be hydroisomerized inthe same reactor. They can be 'separated and hydroisomerized separately. It is `also within the scope of the invention to vrecycle low octane number components of the hydroisomferization-product to the hydroisomcrization reactor 19.
Thus, the reactor eluent of line can be fractionally distilled Vor subjected to molecular sieve separation or to -other separation techniques'to obtain a fraction enriched in n-pentane, n-hexane and/or methylpentanes. This `fraction is then recycled to the hydroisomeri'zation feed `line 18 while the fraction enriched in isopentane and di- :include a temperature from 850 to 950 F., a pressure from 300 to 700 p.s.i.g., a Vliquid-hourly,space velocity from A1 to 4 vol./vol./hr. and a hydrogen to hydrocarbon ratio from 3,000 to 10,000 s.c.f./bbl. These ranges may in part overlap the ranges of conditions suitable for the isomeriziation stage. However, for any specific combinationof ,conditions for the isomen'zation and fixed-bed reforming stages, the hydrogen concentration is higher, the temperature is higher and the space velocity is lower in the reforming stage than in the isomerization stage. When thexedbed reforming .conditions are maintained withinthe. ranges ,indicated and the char-ge is a C7 to about .36.0 .F fraction which is substantially free of oletins and .offlow sulfur content, the reactor can be maintained on- .streani .for very'long cycles, Vfor example, for as long as .lOQbarrels .of charge per pound of catalyst or longer, without-,the necessity of catalyst regeneration.
' The catalyst for the fixed-bed reforming stage can be a catalyst o f the type used inthe'hydroisomerization stage that'is to say, a halogen-promoted platinum-on-alumina Catall/.St "However, somewhat lower halogen concentrations will be used for the reforming stage catalyst and thecataly'st support can be a material other than alumina. Suitable supports or carriers other than alumina include: fresh, aged or deactivated silica-alumina composites, silica-magnesia, bauxite and the like. A i
In the drawing we have shown the stage in which the middle gasoline fraction is reformed in contact with a fixed-bed supported platinum catalyst as a single stage contact in a single reactor. However, as known in the art, this reforming procedure, which involves a number of diierent reactions results in a net temperature drop across the reactor. Advantageously, intermediate heating stages are used to maintain reaction temperature. Conventional fixed-bed platinum catalyst reforming processes employ a series of reactors, each having its own preheater to raise the temperature of the hydrocarbon stream after a drop in temperature in the preceeding reactor. Therefore, instead of the single reforming reactor `23 shown in Figure l, our process can, as in conventional platinum catalyst hydroreforming, employ a series of reactors, a preheaterbeing used for each reactor.
The heavy fraction in our process can have an initial boiling point from about 340 to 380 F. and an end point from about 410 to 500 F. This fraction has a considerably higher initial point than the fractions normally charged'to uid hydroreforming. However, it is a feature of our invention that the lighter hydrocarbons, other than the C5--C6 parafiins charged to the isomerization stage, are reformed in a fixed-bed platinum catalyst reformer and the heavy naphtha hydrocarbons are reformed in a fluid catalytic reformer employing continuous regeneration of the catalyst and a high reaction temperature. Under the reforming conditions that we use in the fluid hydroreforming stage, hydrocracking is extensive and the product has a considerably lower average molecular weight than the charge. Suitable reaction conditions for the stage in which the heavy fraction is reformedv in contact with the uidized reforming catalyst include a` temperature from 850 to 980 F., a pressure from 200 to600 p.s.i.g., a liquid-hourly space velocity from l to 3 vol./vol./hr. andv a hydrogen concentration from 3,000 to 10,000 s.c.f./bbl. The catalyst in this stage is a finely divided supported molybdenum oxide catalyst. This type Y of catalyst consists of 5 to 20 weight percent molybdenum.
oxide deposited on activated alumina. The alumina can contain a small amount of silica, for example, about,5 percent by weight, which improves the surface characteristics of the support.
As Figure 1 shows, the product from the fluid hydrotions.
the catalyst composition.
the treatment of olefinic gasolines such as the products of catalytic or thermal cracking. We can treat the olefinic j'gasoline indifferent ways. One procedure is shown in Figure 1 of the drawing in which we fractionate the olefnic gasoline to obtain a light fraction ranging from C to 360 F. end point material, and a heavy fraction boiling from 360 to 450 F. The light olenic fraction, which will have an octane rating from about 90 to 94 (Research,- clear)V is blended to form part of the final gasoline product. The heavy fraction is mixed with the heavy straight run fraction charged to the uid catalytic hydroreforrning stage. This type of reforming procedure which employs catalyst regeneration is ideally suited for reforming an olei'inic gasoline Which would be unsuitable as a charge stock for .the non-regenerative fixed-bed platinum catalyst reforming stage.
' In still another modification of our procedure for upgrading olefinic gasoline, the olefinic gasoline is separated into two fractions, a light fraction composed of C5 and C5 hydrocarbons, and a heavy fraction composed of the rest of the olefinic gasoline boiling up to about 450 F. The light fraction comprises a portion of the final gasoline product and the heavy fraction is passed to the `fluid catalytic hydroreforming unit.
The choice of procedures for treating the olefnic gasoline will depend upon various circumstances. If the C5- 360'F. light fraction of the olenic gasoline is of suiciently high octane rating, for example, 85 Research, clear, or higher, it will usually be satisfactory to blend this .fraction directly with the final gasoline product as shown in Figure 1. On the other hand, if the light fraction is not of sufciently high octane rating the procedure of Figure 2 is preferable.
In the procedure of Figure 2 the olelinic gasoline is separated in column 40 into three fractions: a C5-C5 light fraction taken overhead via line 41, a (lq-360 F. end point middle fraction withdrawn via line 42 and a S60-450 F. heavy fraction withdrawn via line 43. The light fraction, which will contain C5-C5` olefins as'well as some straight chain and branched chain C5-C5 parains, will have an octane rating from about 85 to 95 Research, clear, and is passed, after separation from light gases, directly to the final gasolineV blending. The middle fraction, having an octane rating from about.85 to 90 Research, clear, can be upgraded by reforming. However, this fraction is too highly olenic for satisfactory charging to the fixed-bed platinum catalyst reformer. Therefore, the fraction is subjected to a mild hydrogen refining pretreatment in reactor 46 inwhich olefins are saturated and sulfur is removed. The pretreating is in accordance with known hydrogen refining procedures and consists of contact with a fixed-bed hydrogenation catalyst in the presence of hydrogen under mild reaction condi- Suitable catalysts include pellets or granules of molybdenum oxide on alumina, cobalt molybdate on alumina, or the like. The hydrogenating metal or metal oxide component, i.e., the molybdenum oxide or cobalt molybdate, will comprise from 5 to 20 weight percent of The alumina can contain a small amount, e.g., 5 weight percent, of silica as a stabilizer.. The mild hydroreiining reaction conditions include a temperature from 600 to 750 F., a pressure from 300 to 600 p.s.i.g., a liquid-hourly space velocity from 3 to l0 vol./vol./hr. and a hydrogen-hydrocarbon ratio from 500 to 2000 s.c.f./bbl. The saturated and desulfurized product from reactor 46 is charged with the middle .straight run fraction to the fixed-bed platinum catalyst reforming unit 23. The heavy olefnic gasoline fraction is charged to the fluid catalytic hydroreforming unit 28 in admixture with the heavy straight run fraction.
Example l below illustrates the results that are obtainable when the process of our invention is applied to the upgrading of a debutanized 462 F. end point Kuwait straight run naphtha as defined in the following table:
8 INSPECTION OF KUWAIT STRAIGHTRUN The naphtha is fractionated to obtain a 22.0 volume percent C5-C6 `fraction boiling from 96 to 160 F., a
v54.0 volumepercentmiddle fraction boiling from 160 `to 360 ,F., anda 24.0 v olume percent bottoms fraction boiling from 360 to 4.62 F..r Theoverhead fraction Vis againseparated by distillation into two fractions, a 31.0 volume Vpercent voverhead fraction consisting essentially of isopentane, boiling from Vto 90 F., and a 69.0 volume percent bottoms fraction containing n-pentane, isohexanes, and normal hexane and'boiling from 90 to 160 F. The latter overhead fraction 'has an octane rating of 92.3 (Research, clear) Research, +3 cc. TEL/ gal.) and is passed to final gasoline product blending. The bottoms lfraction is heatedV to 780 F. and then at a space velocity of 8.0 vol./vol./hr., in admixture with 500 s.c.f. of hydrogen per barrel of hydrocarbon, and at a pressure of 500 p.s.i.g.' is passed through a hydroisomerization reactor containing a xed-bed of halogen-promoted platinum-on-alumina catalyst. The reactor liquid efliuent'is separated from light effluent gases and the unconsumed hydrogen is recycled to the reactor. The consumption of hydrogen amounts to less than 50 s.c.f./bb1. of hydrocarbon charged. A liquid product amounting to 98.5 volume percent of the light fraction charged to the hydroisomerization reactor is recovered. This product has theY following characteristics:
Isopentane- 29.5 n-Pentane 19.2 n-HeXane 10.5 Branched hexanes 33.7 Saturated cyclics 3.0 Benzene 3.6 C7 and heavier 0.5 Gravity: API 86.9
Sulfur: percent 0.003
Octane number: Y
CFRR, clear 'CFRR, +3 cc. TEL 99.7
The middle fraction vof the naphtha feed stockis mixed with hydrogen in a concentration of 7500 s.c.f./bbl. of hydrocarbon; the mixture is heated to 930 F. and at a Vspace velocity of 3.0- vol.'/vol./hr. and a pressure of 500 p.s.i.g. is passed in contact with afxed-bed of-halogen-promoted platinum-on-alumina catalyst. Hydrogen is separated from the 'reactor effluent and is recycled to the reforming reactor feed and to the feed to the hydroisomerization stage. The net yield of hydrogen amounts to 400 s.c.f./bbl. A reformate amounting to 80.1 volume percent of the feed tothe fixed-bed reformer is recovered. This product has the following characteristics:
Gravity: API 50.5
Sulfur: percent 0.003
CFRR, clear 90.1 CFRR, +3 cc. TEL 98.8
IBP F 118 EP F 406 F 160 50% F 232 `The bottoms from the straight run naphtha fractionation is mixed with hydrogen in a concentration of 6000 sci/bbl. of hydrocarbon, is preheated to a temperature of 930 F. and charged to a catalytic reactor containing a iluidized bed of molybdena-on-alumina catalyst .at a space velocity of 1.2 vol./vol./hr. and -a pressure of 350 p.s.i.g. Y The product is separatedfrom hydrogen which is recycled. The yield of hydrogen is 33,0 s.c.f./ bbl.
`The yield of liquid product is about 71 volume percent ofthe hydrocarbon charge Ato thepfluid catalytic reforming reactor. The product has the following character- This product is separated into two fractions, an 88,9
-volurnc percent overhead fraction boiling from 97 F. -andan 11.1.volume percent bottoms fraction boiling from 399 F. The light overhead fraction has thefollowing `This overhead fraction from the ilui'd bed reformer is 'passed to final gasoline product blending and the bottoms fraction is passed to fuel oil blending. The final gasoline product formed by blending the straight run isopentane from thelight fraction of the feed, the first stage lisomerization product, the fixed-bed platinum" catalyst reforming product and the light fraction of theuid bed `reforming product amounts to 80.1 volume percent of the debutanized 462 F. end point straight run naphtha and has the following characteristics:
INSPECTION OF FINAL GASOLINE PRODUCT Y Gravity: API n 61.1 Sulfur: percent 0.004 Octane number:
CFRR, clear 89.9 CFRR, +3 Cc. TEL 100.2 I Distillation, D-86: IBP ,F- 82 EP F 406 170% 4 F 114 50% F 244 90% F `372 Example 2 below illustrates the results that are obtainable when the process of our inventionk is applied to a naphtha as treated in Example 1 above and a debutangasoline pool comprising a 462 F. end point straight run .'10 'ized i440P l-Ffencl pointluid catalytic cracking distillate vas defined in the followingtable:
INSPECTION OF FCC DISTILLATE Example 2 Thestraight run-naphtha is fractionated and they fractions are treated substantially in the same way as described in Example 1. iinic distillate of the above table is separated into two fractions, v2111.846 volume-percent overhead fraction boiling from 1.14.1:0 -352-F. and..a15.4 volume percent bottoms Vfraction boiling-from--365 to 457 F. The overhead ole- *nic fractionhas the following characteristics:
Gravity: ARI '60.5 -Sulfvurz percent l 0:16
CFRR, clear l90.5 JCFRR, +3 ce. TEL/Gal 96.8 Distillation, D-86:
IBP F 114 EP F 352 10% F 145 50% F 215 90% F 312 The bottoms olefinic fraction has the following char- 'acteristics Gravity: API 33.8
Sulfur: percent 0.66 Octane number:
CFRHR, clear 84.6 CFRR, +3 cc. TEL/Gal 90.9 Distillation, 1)-86:
F 365 F 457 F 383 F 392 90% F 414 'The overhead fraction of the FCC distillate is passed to final product blending While the bottoms fraction lis blended-with the 360 to 462 F. bottoms fraction of the straight run naphtha and is charged to fluid catalytic reforming under the conditions described in Example 1. The reactor effluent is separated from hydrogen which-is Vrecycled to the reactor feed. The yield of liquid reformate is about 71 volume percent of the reactor feed. The reformateis separated into two fractions, an 86.5 volume :percent overhead fraction boiling from 101 to 399 F. and a 13.5 volume percent bottoms fraction boiling from v399 to 550 F. The overhead fraction of the reformate has the following characteristics:
Gravity: API 47.3 Sulfur: percent 0.017 Octane number:
CFRR, clear 94.9
CFRR, +3 cc. TEL/ Gal 101.4 Distillation, D-86:
F 101 EP F s99- 10% F 154l 50% F '28s 90% F ssa The catalytically lcracked 'olev Gravity: API v Sulfur: percent 0.051
The bottom fraction of the reformate has Aa gravity of about 12.3 API and a boiling range from about 399 to 550 F. Y l
The final gasoline product is preparedby blending the straight run isopentane separated from the straight run naphthaythe hydroisomerization product, thexed-bed platinum catalyst reforming product, the overhead fraction of the-Huid catalytic reforming-product and the unconverted overhead fraction of the FCC distillate.; Y The nal gasoline product amounts to 84:7 volurnel'percent of the total feed consisting of the Vstraightrun Kuwait naphtha andthe FCC distillate and has the following characteristics: Y
Example 3 below illustrates the results obtaintable when the process of our invention is applied to a gasoline pool comprising a 462? F. end point straight run naphtha .as treated in Example 1 and a debutanized 449 F. end point thermally cracked gasoline as'dened in the following table:
INSPECTION OF THERMALLY CRACKED GASO- Gravity: API Y v 60.4 Sufur: percent 0.058 Octane number:
CFRR, clear .90.3 CFRR, |3 cc. TEL/Gal 99.0 VDistillation, D-862 IBP F 82 EPv F 400 10% f. F-- 114 50% F-.. 241 90% F-- 369 Octane number:
vCFRR, .clear 75.8 CFRR, :+3 cc. TEL/gal. 88.7
' IBP' F 170 EP F 350 10% F 177 50% F 260 90% F 332 The Ybottoms fraction of the olenic thermally-cracked gasoline has the following characteristics:
Gravity: API 31.5 Sulfur: percent 0.15 Octane number: Y
CFRR, clear 71.6 CFRR, -l-3`cc. TEL/gal. 83.4 vDistillation, D-86:
IBP F 360 EP F 450 `10% F-- 369 50% F 405 90% F 441 The overhead fraction, being of sufficiently high octane rating, is passed to final product blending. The middle fraction is mixed with excess recycle hydrogen from the fixed-bed platinum reforming stage in a concentration of 4000 s.c.f./bbl., ythe hydrocarbon-hydrogen mixture is heated to 650 F. and'is passed in contact with a fixedbed nickel-cobalt-molybdenurn-on-alurnina catalyst at a space velocity of 3.0 vol./vol./hr. and a pressure of 400 lp.s.i.g. The product of this hydrogen treatment is separated from light gases and is blended with the middle fraction of the straight run naphtha for charging to the y fixed-bed platinum catalyst reforming stage under substantially the conditi-ons described in Example. 1. The reformate from the fixed-bed reforming stage amounts to 83.4 volume percent of the feed mixture comprising the The straight run naphtha is fractionated and the fractions are treated substantially in the same way as described in Example 1. The olefmic thermally cracked gasoline of the above table is separated into three frac- `tions, a 14.5 volume percent overhead fraction boiling from 86 to 160 F., a 65.0 volume percent middle fraction boiling from 170 to 350 F. and a 20.5 volume per-` cent bottoms vfraction boiling from 360 Ito 450.F. The overhead fraction of the thermally cracked gasoline has the following characteristics: Y
CFRR, clear 86L3 CFRR, +3 cc. TEL/ gal. 95:8 Distillation, D-86:
IBP F 86 EP F 160 The middle fraction of the thermally cracked gasoline has the following characteristics:
Gravity: API 56.9 Sulfur: percent 0.17
' Gravity: API
middle straight run fraction and the hydrogen treated mid- ,dle fraction of the thermally cracked gasoline and has the following characteristics:
Gravity: API 46.5 Sulfur: percent '0.004 Octane number:
CFRR, clear 91.6 CFRR, +3 cc. TEL/gal. 98.4 Distillation, D486:
IBP F 118 EP F-- 405 10% F-- 152 50% F 251 F 362 The bottoms fraction of the thermally cracked gasoline is blended with the bottoms fraction of the straight run naphtha "for charging to fluid bed reforming under substantially the conditions described in Example l. The reactorefuent is separated from hydrogen and light gases and a liquid product yield of about 7l volume percent of the reforming feed is obtained. This product is separated into two fractions, an overhead fraction comprising 87.7 volume percent of the reformate and a bottoms fraction comprising 12.3 volume percent of the reformate. The bottoms fraction is passed to fuel oil blending. 'I he overhead 'fraction is passed to final gasoline product blending. The nal gasoline product, composed of the straight run isopentane, the hydroisomerization product, the fixed-bed platinum reforming product and the uid bed reforming product amounts to 81.9 volume percent of the gasoline pool, comprising the straight Vrun naphtha and the thermally cracked gasoline and has the following characteristics 57.8 Sulfur: percent 0.008
Obviously many modifications and variations of the invention as hereinbefore set forth may be made Without departing Ifrom the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims.
1. A process for increasing the octane rating of gasoline which comprises fractionating a full range straight run gasoline to obtain a light parafinic fraction consisting essentially of C and C6 paraflns, a middle fraction having an end point from about 320 to about 360 F. and a heavy residual fraction of about 450 F. end point, increasing the octane rating of said light fraction in a hydroisomerization stage comprising contacting straight chain C5 and C6 paraiiins in admixture with hydrogen with a fixed-bed, halogen-promoted, platinum-on-alumina catalyst under hydroisomerization conditions including a hydnogen concentration from about 50 to 1,000 s.c.f./ bbl. of hydrocarbon, a liquid-hourly space velocity greater than 5 vol./vol./hr. and a temperature from 600 to 850 F. and recovering a product of substantially the same average molecular weight as said light fraction and higher branched chain paran content, increasing the octane rating of said middle fraction in a fixed-bed catalytic reforming stage comprising contacting said middle fraction in admixture With hydrogen With a fixed-bed, halogenpromoted, platinum-on-alumina catalyst under reforming conditions including a hydrogen concentration from 3,000 to 10,000 scf/bbl., a liquid-hourly space velocity from 1 to 4 voL/voL/hr. and a temperature from 850 to 950 F., separating light gases from the reactor effluent of said fixed-bed catalytic reforming stage and obtaining a normally liquid product entirely of the gasoline boiling range and of higher aromatic content and octane rating than said middle fraction, treating said heavy fraction in a fluid catalytic reforming stage wherein said heavy fraction in admixture with hydrogen is contacted with a iluidized supported molybdenum oxide catalyst under reforming conditions including a hydrogen concentration from 3,000 to 10,000 s.c.f./bhl., a space velocity from l to 3 vol./ vol/hr., and a temperature from 850 to 980 F., recovering a conversion product of substantially lower average molecular Weight and higher aromatic content than said heavy fraction, fractionating said product to recover a light fraction and a residual fraction, and blending said light fraction with the entire normally liquid hydrocarbon products of said hydroisomerization stage and said tixedbed catalytic reforming stage to obtain a gasoline product having an octane rating of at least about 90 Research, clear.
2. A process for increasing the octane rating of a renery gasoline pool including straight run and oleinic gasoline which comprises fractionating a full range straight run gasoline fraction to obtain a light paraiiinic fraction consisting essentially of C5 and C6 parains, a C7 to about 360 F. middle fraction and a heavy fraction boiling from about 360 to 450 F., fractionatng a full range olefinic gasoline to obtain a light fraction comprising C5 and C6 hydrocarbons and a heavier fraction, increasing the octane rating of said light straight run frac- 14 tion in a hydroisomerization stage by contacting n-pentane and n-hexane in admixture with hydrogen with a tixedbed, halogen-promoted, platinum-on-alumina catalyst under hydroisomerization conditions including a hydrogen concentration from about 50 to 1,000 s.c.f./bbl. of hydrocarbon, a liquid-hourly space velocity greater than 5 vol./ VOL/hr. and a temperature from 600 to 850 F. and recovering a product :of substantially the same average molecular weight as said light straight run fraction and of higher branched chain paraflin content, increasing the octane rating of said middle fraction in a fixed-bed catalytic reforming stage by contacting said middle fraction in admixture with hydrogen with a fixed-bed, halogenpromoted, platinum-on-alumina catalyst under reforming conditions including a hydrogen concentration from 3,000 to 10,000 s.c.f./bbl., a liquid-hourly space velocity from 1 to 4 vol./vol./hr. and a temperature from 850 to 950 F. and recovering from said fixed-bed catalytic reforming stage a normally liquid product entirely of the gasoline boiling range and of higher anomatic content Iand octane rating than said middle fraction, mixing said heavy olenic fraction with said heavy straight run fraction and treating the resulting combined fraction in a fluid catalytic reforming stage wherein the combined heavy fraction in admixture with hydrogen is contacted with a fluidized supported molybdenum oxide catalyst under reforming conditions including a hydrogen concentration from 3,000 to 10,000 s.c.f./ bbl., a liquid-hourly space velocity from 1 to 3 vol./ VOL/hr. and a temperature from 850 to 980 F.,V recovering a conversion product of substantially lower average molecular Weight and of higher aromatic content than the combined heavy fraction, fractionating said product to recover a light fraction and a residual fraction, and blending said light fraction with the light fraction of said olefinic gasoline and with the entire normally liquid hydrocarbon products of said hydroisomerizatio-n stage and said xed-bed catalytic reforming stage to obtain a gasoline product having an octane rating of at least about Research, clear.
3. A process in accordance with claim 2 in which said full range oleinic gasoline is fractionated to obtain a C5 to 360 F. light fraction and a 360 to 450 F. heavy fraction.
4. A process according to claim 2 in which said full range olefinic gasoline is fractionated to obtain a light fraction consisting essentially of C5 and C6 hydrocarbons and a. C7 to 360 F. middle fraction, said middle fraction being passed in admixture With hydrogen to a saturating and desulfurizing pretreatment comprising contact with a fixed-bed hydrogenating catalyst at a temperature from 600 to 750 F., a liquid-hourly space velocity from 3 to 10 vol./vol./hr. and a hydrogen concentration from 500 to 2,000 s.c.f./bbl., said pretreated fraction being mixed with the straight run middle fraction charged to said fixed-bed platinum catalyst reforming stage.
5. A process according to claim 2 in which said full range olefinic gasoline is fractionated to obtain a light fraction consisting essentially of C5 and C6 hydrocarbons and a heavy fraction consisting essentially of C7 and higher hydrocarbons.
References Cited in the le of this patent UNITED STATES PATENTS 2,249,461 Diwoky July 15, 1941 2,324,165 Layng et al. July 13, 1943 2,651,597 Corner et al Sept. 8, 1953 2,740,751 Haensel et al Apr. 3, 1956 2,834,823 Patton et al May 13, 1958 nur UNITED STATES PATENT OFFICE CERTIFICATE 0E CORRECTION Patent No. 2344959 Robert E. Kline et al.
It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 9YV 11n@ 71, for "0F" 372" read 0E" 375 signed and sealed this 10th day of January 1961.
SEA L) Attest:
KARL H; AXLINE Attesting Ocer ROBERT C. WAT-SGN Commissioner of Patents Ju1y 12, '1960