US2376077A - Production of motor fuel - Google Patents

Description

y 1945. a. a OBERFELL ETAL 2,376,077

PRODUCTION. OF MOTOR FUEL Filed March 14, 1941 2 Sheets-Sheet l DEHYDROGENATION Y ETHANE PROPANE 128 DEHYDROGENA I 46 AROMAT ZAT ION DEHYDROGENAT ION INVENTOR GEORGE G. OBERFELL NES BY JEAN P. O

- A ORNEY y 1945. a. G. OIBVERFELL ET AL 2,376,077

PRODUCTION MOTOR FUEL Filed March 14, 1941 v .2 Sheets-Sheet 2 CATALYTIC ALKYLATION IZATION RE FORM N6 252 2s| Y SEPARAT INVENTOR GEORGE e. OBERFELL BY JEAN P. JONES Patented May 15, 1945 UNITED STATES PATENT OFFICE PRODUCTION OF MOTOR FUEL George G. Oberfell and Jean P. Jones, Battlesville, Okla., assignors to Phillips Petroleum Company,a corporation of Delaware Application March 14, 1941, Serial No. 383,430

9 Claims.

tor fuels having gasoline characteristics and premium qualities especially as to antidetonating values from hydrocarbons available in so-called wet natural gases. It relates still more particularly to the production of such motor fuels in high yields by the utilization of the major part of the 10 C2 and heavier hydrocarbons'available in natural gas.

By far the outstanding trend in motor fuels in recent years has been the tendency toward increase in antidetonating characteristics as measured by increase in octane numbers. Automobile manufacturers have continuously designed their cars to make use of the increased efflcienoy and performance afi'orded by high octane gasolines,-

and refiners have attempted above all to produce go rally occurring normally gaseous mixtures, was in a great demand among refiners because the vapor pressure and volatility afforded by blending natural gasoline with their products allowed them to acteristics of volatile fuels, volatility became the most desired quality, and gasoline and natural gasoline as a blending stock appeared to be the only means to obtain this volatility.

The use of cracking processes for manufacturing gasoline was originally motivated by the desire for higher yields of gasoline and has more re cently been stimulated by the demand for higheroctane numbers. Likewise the more recent use of gas conversion processes has resulted in increased yields of motor fuel stocks with high octane numbers and has also resulted in'the use of lighter hydrocarbon fractions available from natural sources which formerly were wasted. However, from the view point of the natural gasoline industries perhaps the most important effect of cracking and gas conversion processes was the production of more volatile motor fuel stocks in the refineries. As an example of these trends, in Mid-Continent gasolines, during thepast 15 years Table I is presented, which shows clearly that while the volatility of motor fuels has been increasing for many years, this increase has been more than made up by volatile fractions produced at refineries, and there has resulted a decrease rather than an increase in the amount of natural gasoline used per gallon of finished gasoline product.

TABLE I Estimated composition of motor fuel (per cent by volume) Constituent Years l Refinery base (50% evaporated at 284 F.) (includes straight run and heavier cracked frac- 2 Volatile refinery products (volatility characteristics based on 12 lb. natural) (includes vapor recovery and light cracked fractions) 3 Natural gasoline (12 lb. vapor pressure) Ne Ii- 2. 8 9. 4 20. 1 20. 2 20. 5

.gi le 6.2 7.1 7.4 7.0 7.1 6.9

4 Butane.(natural and refinery) out deeper into the kerosine fractions of crude oil and thus produce higher yields of gasoline. Minimum volatility speciflcations'were some of the most important specifications atthat time, and the most dimcult ones to meet. Moreover, with In addition to this, natural gasoline constitutes only a small proportion of the hydrocarbon material available in natural occurring normally gaseous hydrocarbon stocks such as natural gas. In Table II is shown in column 1 the composition of the recognition of the superior performance chara natural gas which may be assumed to be typical.

Tan: 11

Raw natural gasoline, 125' A. P. I.

l 2 I 3 4 5 t N tural I'lmlfld M l li r i l i Com hen a v 0 gm 0 qpo gas, mol per per uid, vol; per g? per cent cent cent cent Methane 87.0 2.2 3.1 Ethane 6. 0 l0. 0 l2. 0 Propane 4.0 37.0 40.3 Isobutane. 1 7 7.9 7.2 N-butane- 24.0 22.8 Isopenhne.-. 5. 6 4. 6 N- tane. 4.9 4.2 Iso l. 3 3. 3 2. N-henne 2.2 1.6 Heptanes and 3. 0 l. 7

heavier A very large proportion of this natural gas is methane which as yet is still practically unavailable for conversion in the motor fuel stocks. Only about 3 mol per cent of this natural gas comprises 04 and heavier hydrocarbons, which are normally included in natural gasolines, and although there is a large proportion of natural gas which is methane, there is roughly three times as much ethane and propane as material available directly for natural gasoline. Processes are now available which without undue expense can extract substantially all of the C: and heavier hydrocarbons from such natural gas. Column 2 and 3 respectively of Table II show the composition of the product which can be extracted from this natural gas in commercial quantities without undue expense. It will be noted that although this product contains only a small portion of the available ethane, nevertheless on a liquid volume basis not more than about 30% comprises those constituents which make up natural gasoline, since ordinarily only about one-half or less of the butanes are included to form a 26-70 natural gasoline. The approximate composition of a natural gasoline blending stock known to the trade as 26-70 natural gasoline is shown in column 4, together with the octane number of the principle fractions which are shown in column 5.

The lightest third of 26-70 natural gasoline is butane hydrocarbons whose vapor pressure makes it unsuitable for blending directly into motor fuel in any large proportion. Because of the limitations to its use as a blending stock large quantities of butane are now being processed in polymerization operations or are being marketed as such in a variety of fuel applications. Half of the remainder of natural gasoline consists of pentanes which are hydrocarbons of intermediate vapor pressure but which have a high volatility so that these materials can not be used in large percentages in blending with many other motor fuel stocks because of their effect in increase in the volatility of the final gasoline product as indicated by the percentage evaporated at 212 F.

The other half of butane-free natural gasoline is a low vapor pressure hexane and heavier fraction. About ten years ago this fraction had an octane number which compared favorably with the average octane number of motor fuels of that time. However, at present the average octane number of most of the gasolines on the market is around 75 or even higher and as a result the low octane number of this portion of natural gasoline places it in the same class as low end point straight run gasoline.

It is. therefore, readily seen that in order to utilize natural occurring low boiling hydrocarbone to the maximum advantage it is necessary to increase the octane number of fractions of low volatility which are directly available as well as to convert hydrocarbons-of 2-5 carbon atom per molecule into hydrocarbon fractions which have high octane numbers and which are not highly volatile.

We have now invented a process which produces high yields of motor fuel stocks having gasoline characteristics, or suitable for. blending stocks to produce such gasolines, which utilizes to a high degree of emciency substantially all of the C2 and heavier hydrocarbons which can be obtained from natural gas, or similar hydrocarbon sources, by a combination'of process steps which not only cooperate to produce products which.

may be successfully blended together, but which are also so cooperatively combined that byproduct fractions from one proces step are efficiently utilized in other process steps along with hydrocarbon fractions primarily charged to such other process steps. l

It is an object of our invention to produce a motor fuel stock of high value from lower boiling hydrocarbons.

Another object of our invention is to utilize the ethane and heavier constituents of natural gas to maximum advantage in the production of motor fuel.

A further object of our invention is to establish a process for treating naturally occurring gaseous and liquid hydrocarbons to produce a composite blended motor fuel with well balanced characteristics.

Another object of our invention is to produce from any mixture or mixtures of normally gaseous hydrocarbons of limited methane content a motor fuel having high antiknock qualities, and to produce such a motor fuel in a particularly high yield with reference to the hydrocarbons treated and/or available.

Still another object is to separate from a natural gas substantially all of the C2 and heavier 45.hydrocarbon content therein and to produce therefrom a normally liquid motor fuel whose volatility, saturate content, and aromaticity may be varied at will.

Still another object of our invention is to establish a process in which separate constituents of a hydrocarbon mixture extracted from a wet natural gas are subjected to various conversion steps to produce motor fuel stocks which can be blended together to produce a composite motor fuel of gasoline characteristics, the said conversion steps cooperating among themselves to effect the conversions in an optimum manner with high yields.

Other objects and advantages of our invention will become apparent from the accompanying description and disclosure.

In the present specification and claims by m0- tor fuel of gasoline characteristics is meant a hydrocarbon mixture, which may or may not contain small amounts of added chemicals such as antidetonants and gum inhibitors and the like. which will meet any set of the various specifications recognized in the trade for gasoline. As an example of such specifications the following Table III is quoted from the Bureau of Mines Report of Investigations 3492. These, however, are not necessarily to be considered limiting as to any particular characteristic or group of characteristics. In addition to the characteristics shown, it is assumed that all the gasolines are sweet and contain inhibitors to prevent excessive gum formation where necessary, and meet any other qualifications usual to the trade.

Tun: 111

Motor gasoline survey (ranges of 90% of fuels tested) Regular price Premium price gasoliues gasolines Summer Winter Summer Winter 1936 1938-33 1036 1038-39 Gravity... API.. 56. 8-62. 59.1-66. 6 56.9-05. 6 59. 3-669 Sulfur. -.per cent 0. 023-0. 20 0. 026-0. 24 0. 019-0. 087 0. 021-0. 087 Reid vapor pr'essure 6. 0-9. 1 8. 4-12. 1 5. 2-8. 8 7. 5-11. 7 68. 0-71. 0 69. 4-72. 5 74. 0-81. 0 75. 9-81.13

94-114 83-97 95-118 85-1 135-161 114-141 133-164 118-147 160-192 133-174 159-188 138-175 180-218 154-201 176-214 158-199 229-264 209-255 206-257 203-246 273-310 264-304 239-306 236-293 335-371 336-371 286-365 280-363 End point 383-419 386-415 343-417 360-413 Distillation 1055.. 1. 0-2. 5 1. 3-3. 4 0. 8-2. 3 1.0-3. 2

Reference will nowbe made to the drawing which forms a part of the specification and which diagrammatically illustrates by way of a flow sheet an arrangement of apparatus in which our invention, together with various modifications thereof, may be practiced. In the description of this drawing the various process steps will be described in connection with optimum conditions for their operation, which'will serve as examples thereof,

Referring now to the drawing;a suitable hydrocarbon mixture, such as the natural gas whose composition was given in Table II or such as the raw natural gasoline separated therefrom whose composition is also given in this table, is charged to a suitable separating apparatus ll through pipe "I. The separating or fractionating apparatus II is diagrammatically illustrated as a fractionating column. It will be appreciated, however, that in actual practice if fractional distillation means only are used, such a separation as is to be hereinafter described will ordinarily require a series of fractionating columns together with normally occurring attendant auxiliary apparatus, and that in many cases it will be desirable to conduct at least one or more of the separations by means of absorbents such as are well known to the art. Extremely light constituents such as methane and inert gases may be removed through a pipe 12 controlled by a valve 13. It is not primarily an object of this invention to A. Ethane B. Propane C. Isobutane D. Normal butane E. Isopentane 1". Normalpentane Ci. Hexanes and heavier (in the gasoline range) dehydrogenated in the presence of any one ofa large number of known dehydrogenation catalysts, it is very satisfactorily dehydrogenated in the absence of catalysts by being heated to a high temperature at a low pressure.

. for such a thermal dehydrogenation are a temperature between about 1200 and 1500 F. and a pressure not substantially in excess of 100 pounds per square inch, preferably about 5-30 pounds per square inch gauge, for a period of time such as to efl'ect a content of about 10 or 15 to 40 or '45 per cent unsaturates in the efiluenti gases. This dehydrogenation is readily accomplished by passing the ethane fraction through a suitable tube coil in a furnace. The dehydrogenation eflluent is passed through pipe 20 to separating means 21 wherein a normally gaseous unsaturated hydrocarbon fraction, which will be predominantly ethylene, is separated from other constituents. Light gases comprising primarily methane and hydrogen are removed from the process through a pipe 22 and controlled by valve 23. Undesirably heavy hydrocarbons are removed from the process through a pipe 24 controlled by valve 25. The 'separatingmeans 21 will generally be so operated that the ethylene fraction will also generally contain unsaturated Ca hydrocarbons and may also contain unsaturated C4 hydrocarbons when their presence is not deleterious in the subsequent reaction steps, as well as corresponding parailfins. Such an ethylene fraction is removed through a pipe 26 for subsequent reaction with heavier hydrocarbon fractions as will be hereinafter discussed. A suitable ethane fraction from an outside source, or separated from other process steps of our invention, may be introduced through pipe 21 and valve 28 to pipe ii.

In many methods of operation it will be found desirable to include a substantial part of the protreat hydrocarbons which boil substantially above the end point of gasoline, that is above about 400 to 450 F.,' and any such heavy hydrocarbons which may be present in the material charged through the pipe l0 may be removed from the so large that the fraction can not be satisfactorily identified as shown. In some instances an individual fraction may comprise the indicated hydrocarbon in a purity of about 95 per cent or more.

pane present in the material charged through pipe I 0 in the ethane fraction for conversion into ethylene and propylene, so that the fraction will be better termed an ethane-propane" fraction. In most instances, however, it will be desirable to separate at least a substantial portion of the propane fraction for separate treatment. In these cases a propane fraction is removed from the separating means H through pipe 30 and valve 3| and is passed through valve 32 to a react on zone illustrated by reaction coil 33, situated in a suitable furnace or the like 34, wherein the propane is reacted under alkylation conditions with ethylene, produced in the step just descr bed, which is passed from pipe 28 through a pipe 35 and is introduced to the reaction mixture and reaction zone 33, preferablyat a plurality of points, such as are represented by pipes 36 and 3'! controlled Such conditions ature, pressure and reaction time should be so controlled that appreciable conversion of propane by itself would ordinarily not take place. The

unsaturates are so introduced that their concentration at any one point will not exceed about 10 per cent by weight, and in many instances will not be in excess of about 1 or 2 per cent by weight. The efliuent of this alkylation step is passed through a pipe 40 and a valve 4| to a suitable separation means 42. The products of the reaction will be primarily C5 to Ca hydrocarbons, isopentane being the predominant single hydrocarbon. An isopentane fraction is removed from separating means 42 through a pipe 41, and may be discharged from the system for any desired use through a valve 0 or may e passed from pipe I! through pipe III, for further use within the process as will be described, and/or through pipe 2" for blending with other products. Light hydrocarbons may be removed from the process and from separating means 42 through a pipe 03 controlled by a valve 4|. This fraction will generally comprise the larger part of the unreacted propane and lighter hydrocarbons which may be separated and returned to the system either directly to separating means II as through pipe It, or may be mixed directly with the correspondin fraction or fractions removed through pipe It by being added thereto through pipe 50 and valve 5| for propane, or through pipe 21 for ethane. A normal pentane fraction, which may contain heavier hydrocarbons in the gasoline range, may be removed from separating means 42 through a pipe I! and may be discharged from through valve 53, or may be passed through pipe 54 and valve 55 for subsequent use in the process as will be hereinafter described. Heavier hydrocarbons may be removed from separator 42 and from the process through pipe 45 controlled by valve 4..

In many cases at least a portion of the propane fraction may be subjected to more or less nondestructive dehydrogenation to form propylene for su nt reaction in a catalytic alkylation step to be described. In such a case a suitable portion of the propane fraction may be removed from pipe through a pipe 56 and valve 51 to a dehydrogenation unit II. The dehydrogenation in unit 58 may be carried out noncatalytically. but in most cases it will be preferable to conduct a more or less clean-cut dehydrogenation to propylene with a minimum production of ethylene, and this is best accomplished by use of a suitable dehydrogenation catalyst such as chromium oxide, alone or in admixture with other oxides such as are known to the art. The dehydrogenation temperatures should generally be between 900 and 1300 1". preferably about 950 to 1200 F., and pressure should not be in excess of 100 pounds per square inch, and will preferably be between 5 and 30 pounds per square inch gauge. The reaction time should be such that about 15 to 30 or 40 per cent of the eiiiuent is unsaturated hydrocarbon material. The eiliuent or the dehydrogenation the process unit I. is passed through the pipe 59 to the separating means 00. When desired light materials, which will be primarily hydrogen together with some methane, may be removed from separating means ll and from the process through pipe 6| controlled by valve 82. A hydrocarbon fraction containing the desired unsaturated hydrocarbons are removed through pipe 83 and valve 64 for subsequent use as will be hereinafter described. Heavier hydrocarbons present may be removed through a pipe 65 and avalve 68.

An isobutane fraction is removed from separator means il through a pipe 10 and valve 1i and may be passed through valve 12 to a suitable alkylation unit such as is represented by reaction coil 13 located in a furnace or other suitable heating means ll. Unsaturated C: and/or C3 hydrocarbons produced in dehydrogenation unit It may be passed to the alkylation unit I3 from pipe 20, and are preferably introduced to the reaction mixture in the reaction zone 13 at a plurality of points, such as are represented by pipes 16 and I1 controlled by valves 18 and 19 respectively. The reaction in coil 13 is preferably conducted under conditions substantially the same ashas been discussed in connection with the alkylation of propane with a similar unsaturated material in reaction coil 33. When the unsaturated hydrocarbon material passed through pipe 26 is primarily ethylene, the principal product produced by the alkylation in coil 13 under these conditions will be hexanes, heptanes and octanes, of which the predominant constituent will be neohexane. The eiliuent of the reaction coil 73 is passed through a pipe and valve 8| to separating means 82. A suitable alkylate fraction, which may under suitable conditions be substantially pure neohexane, is removed from separating means 82 through a pipe 83 and may be discharged from the process through valve 84 or part or all of the fraction may be passed through pipe 85 and valve 88 to pipe 255 for blending with other products, as will be described. Undesirably light material will be removed from separatin means 82 through pipe 81 controlled by valve 88 and undesirably heavy material may be removed through 89 controlled by valve 90. An unreacted C4 hydrocarbon fraction is removed from separating means 82 through a pipe 9i and may be passed entirely or in part back to pipe 10 through valve 92. This hydrocarbon fraction will contain an appreciable although small amount of unsaturated hydrocarbons, and since it also has a very high proportion of lsobutane it will serve as an excellent charge stock for catalytic alkylation with other low boiling unsaturated hydrocarbons. To accomplish this a part or all 01' the material passing through pipe 9| may be removed through pipe 98 controlled by a valve 94 and passed to a catalytic alkylation unit 95. In many instances a substantial portion of the isobutane may be passed directly from pipe 10 throu h ipe 96 and Y valve 9! to pipe 93 and this catalytic alkylation step.

The proylene fraction produced by dehydroenation in unit 58 serves as an excellent source of unsaturated material for this catalytic alkylation and may be introduced into pipe 93 from pipe 63 for this reaction. In alkylation unit 95 the hydrocarbons brought thereinto by pi e 93 are treated in the presence of a suitable alkylation calatlyst to form isoparafllns predominantly of 7 and 8 carbon atoms per molecule, which have high octane numbers and low volatility and are therefore desirable ingredients for the as'rao'rv I gasoline product of our invention. The alkylation process preferably uses a catalyst such as an aluminum halide catalyst, especially aluminum chloride or bromide or any one of numerone metal halo-aluminates known to the art such as sodium chloro-aluminate, or zinc chloride or bromide, boron fluoride or zirconium tetrachloride or the like, or concentrated sulfuric acid, or concentrated hydrofluoric acid.

It a catalytic alkylation process involving a liquid or a mobile catalyst is used, the catalyst may be fed to the system through pipe 00 controlled by valve 99. In such a process it is advantageous to use sulfuric acid or hydrofluoric acid as the catalyst, since these catalysts appear to be more selective than some of the other alkylation catalysts for the alkylation of isoparafilns, and cause a minimum of side reactions. To minimize concurrent polymerization reactions the mixtur of hydrocarbons in the catalyst should be intimately contacted, and the concentration of unsaturated hydrocarbons in any one portion of the mixture preferably should be kept low relative to the concentration of isoparaflins, as may be effected by multipoint addition of olefins to a reacting stream, recirculation of a portion of the reactants in a closed cycle, and the like. In most instances a suitable reaction temperature will be found between about 0 and 125 F., generally between about and 10 F., although higher or lower temperatures may be used, as may be found most suitable for the catalyst used. The hydrocarbon efiluent is passed through a pipe I00 to a separator IOI wherein heavy, hydrocarbon-immiscible material is separated from the hydrocarbons and removed through a pipe I02 controlled by valve I03. When sulfuric acid or hydrofluoric acid is used as the alkylation catalyst, a substantial portion of this material may often be passed directly from pipe I02 to pipe 90 for re-use in the process. A hydrocarbon eiiluent of the catalytic alkylationis passed from separator IOI through a pipe I04 controlled by a valve I05 to a separating means I06. An alkylate product is removed from separating means I05 through a pipe I01, and may be discharged from the process through valve I08 but in most cases this product will be passed from pipe 101 through pipe I09 controlled by a valve IIO to pipe 255 for blending with other hydrocarbon fractions produced from other steps of the process to give a. finished gasoline product.

Any undesirable low boiling material which is present in the efliuent of the catalytic alkylation step may be removed from separator I06 and from the process through pipe H9 controlled by valve I29, and intermediate fraction such as propane and/or butane may be removed from separating means I05 through pipe II1 controlled by valve II8, and may be returned to the process in the most suitable manner. Heavy hydrocarbons may be removed through pipe I48 controlled by valve I49.

The isopentane fraction separated from separating means 42 through pipe 41, having been produced by thermal alkylation, will often contain a small but appreciable amount of unsaturated hydrocarbons especially if this fraction is so separated that it contains a substantial portion of the C4 hydrocarbons produced in the process. For instance, such a fraction recovered from an alkylation of propane with ethylene had substantially the following composition.

M01 per cent Component At least a part of this material may well make a suitable charge stock for the catalytic alkylation process just described, and its use will tend to produce an alkylate product of high octane number and still lower volatility. To this end a suitable portion of this isopentane fraction may be removed from pipe 41 through pipe III controlled by a valve II2, which passes directly to pipe '93. In some cases it may be desirable to submit a. portion of this material to alkylation in the unit 13, and if such is the case a portion thereof may be passed from pipe III through pipe 3 controlled by a valve II4 passing to pipe 10. Isobutane or isopentane from any desirable outside source, or separated from any of the streams discharged from this process, may be introduced to pipe 10 through pipe II5 controlled by valve II6.

A normal butane fraction is removed from separating means II through pipe I20 controlled by a valve I2I. This normal butane fraction 80 may be treated in any one or more of several manners about to be described, or a portion thereof may be included directly in a final blended gasoline product. When a portion is to be blended with the gasoline directly, it may be passed from pipe I20 through pipe I22 and valves I23 and I24 to pipe 255, or if desired the portion thereof may be removed from the system through a pipe I25 controlled by a valve I26. Normal butane may be advantageously dehydrogenated to form normal butenes which can then be reacted genation carried out in unit I30 is preferably a catalytic operation, more or less as has been discussed for the catalytic dehydrogenation of the propane fraction in the dehydrogenation unit 58. The optimum temperature for the dehydrogenation of normal butane is somewhat lower than that for the dehydrogenation of propane and will generally be found within the range of 850 to 1150 F. preferably between about 900 and 1050 F. The dehydrogenation pressure should again not be in excess of about pounds per square inch, and preferably .is between about 5 and 30 pounds per square inch gauge, with a reaction time such thaththe effluent contains between about 10 and 35 or 40 per cent of unsaturates and generally between about 15 and 25 per cent of unsaturates. Any suitable dehydrogenation catalyst known to the art may be used although we prefer to utilize a catalyst comprising chromium oxide. The dehydrogenation efiluent is passed from unit I30 through pipe I3I to suitable separating means I32. A 04 fraction containing butenes produced by the dehydrogenation, and which may also contain other hydrocarbons such as propylene and/or pentenes which have also been formed in small amounts in the dehydrogenation, is removed from separating means I02 through a pip I 33 and valve I and is introduced to the catalytic alkylation unit 80 by being passed to pipe 83. Undesired low boiling material produced by the dehydrogenation is removed from separating means I02 through a pipe I80 controlled by a valve I80. Any heavier hydrocarbons produced as by-products of the process may be removed therefrom through pipe I31 controlled by valve Il0. In some cases a portion of these high boiling materials may be advantageously included in the charge to the catalytic alkylation step and in such a case may be passed from pipe I31 through pipe I40 controlled by valve Ill to pipe I33, or may be removed as a separate fraction from separating means I32.

Normal butane can be converted inexpensively and with quite satisfactory yields into aromatic hydrocarbons by being subjected to high temperatures' and low pressures, and the aromatic hydrocarbons so produced will iorm valuable constituents of premium motor i'uels. If it is desired to produce such aromatics, a portion of the normal butane fraction may be passed from pipe I20 through pipe I22 and pipe I controlled by a valve I45 to an aromatization unit I 40. In this unit the normal butane fraction is converted at a relatively high temperature of the order of l300-2000 F., more preferably 1400-1750 F., at a low pressure, not substantially in excess of about 200 pounds per square inch, for a reaction time of about 0.01-0.5 second in the absence of catalysts to produce a satisfactory yield of aromatic hydrocarbons. Catalysts such as are known to the art may be used, but satisfactory operation may be obtained in the absence of catalysts. The reaction eiiluents are passed through pipe I41 to separating means I00. Undesirably heavy hydrocarbon material and tar may be removed through a pipe I controlled by a valve I02 and discharged from the system. A desirable aromatic fraction in the gasoline boiling range may be removed through a pipe I58 and passed through a valve I54 to pipe 255 for blending into a final motor fuel product as will be described. If it is desired to separate any portion of this aromatic stream, for the preparation of aromatic products, such a. portion may be separated from pipe I03 through pipe I55 controlled by a valve I00. Any undesirable light material may be removed from separating means I50 through a pipe I01 controlled by valve I58. If it is desired to recycle a normal butane fraction from the emuent of the aromatization unit it may be included in material separated through pipe I01. and after subsequent purification may be reintroduced into the system as through pipe I42, controlled by valve I, or more directly to the aromatization unit by means not shown. Inasmuch as the C4 fraction will contain an appreciable portion 01' unsaturated hydrocarbons suitable for use in the catalytic alkylation step such a fraction may be removed from separating means I00 through pipe I00 controlled by a valve IOI and passed to pipe I" for reaction as has been described.

In most instances the isopentane separated from the material charged through pipe I0 to the process is suitable, without further conversion, as a blending stock. It is also an excellent revalve I00 unit 184. The isomerizatiorr asvao'rr actant for the catalytic alkylation unit 00 and any desired portion may be treated in this manner. An isopentane fraction may be removed from separating means II through pipe I02 corrtrolled by a valve I08 and may be passed through directly to pipe 200 for blending with the finished product or the process. I! desired a portion may be discarded from the process through pipe I00 controlled by a valve 608. Any portion desired for the catalytic alkylation may be passed from pipe I02 through pipe It! controlled by a valve I08 to pipe I03. In some instances it may be desirable that the catalytic allwlation be conducted with isopentane as the low boiling isoparafllnic reactant, in which case. the material passing through pipe I01 will constitute the principal isoparaflinic charge to this step. Isopentane from an outside source may be added to the system, if desired through pipe 00 controlled by valve 09 to pipe I 02.

Normal pentane, although it does not have as high an octane number as isopentane. may also at times be included directly in the finished gasoline without subsequent treatment. However, on account of its low octane number we generally prefer to subject it to an operation which will make it more desirable for use as a gasoline blending stock. Such treatment may be either dehydrogenation, producing pentenes which may be blended directly into the gasoline or which may serve as reactants for the catalytic allsylation, or the normal pentane may be subjected to an isomerization or reforming, either by itself or in combination with other higher boiling hydrocarbons or low octane number as will be subsequently described. A normal pentane fraction is removed from separating means II through pipe I10 controlled by valve I1 I. A portion thereof may be passed through a valve I 12 to a dehydrogenation unit I13, which should be operated under substantially the same operating conditions just described for the dehydrogenation unit I in which normal butane is dehydrogenated. The eilluent of dehydrogenation unit I13 is passed through a pipe I14 to suitable separating means I10. Undesirable low boiling material which will be primarily hydrogen and methane may be discharged through a pipe I10 controlled by a valve I11. A pentene fraction produced by the dehydrogenation may be removed through pipe I10 and passed directly to the catalytic alkylation unit 95 through valve I19 into pipe I 33. If it is desired to blend any portion of this normal pentene fraction directly with the gasoline it ma be passed from pipe I18 through pipe I80 controlled by a valve I8I to pipe I22 and on to pipe 255.

In some instances it may be desirable to isomerize the normal pentane fraction to produce isoparafllns such as isopentane and/or isobutane, which may be recovered as such for blending with the final gasoline product, or which may be passed to the catalytic alkylation unit 95. To this end any desirable portion of the normal pentane fraction may be passed from pipe I10 through a pipe I82 controlled by a valve I83 to isomerization may be conducted by any suitable conditions known to the art and is preferably conducted at a temperature between about 0 and 400 F. and a pressure suflicient to maintain the hydrocarbon material in liquid phase and in the presence 01' an isomerization catalyst such as aluminum chloride or aluminum bromide. The isomerization eflluent is passed through a pipe I85 controlled by a valve I80 to aavao'rv suitable separation means I81. Heavy material, which may include a sludge which contains an isomerization catalyst if the isomerization unit in I84 is operated under conditions such as to produce such a material, may be removed through pipe I88 controlled by valve I89. Any undesirable low boiling material may be removed through a pipe I90 controlled by a valve I9I. A suitable isoparaflin fraction produced by the isomerization is removed through a pipe I92 and may be passed through valve I93 to pipe 255 for blending in the finished gasoline product, or any desired portion thereof may be discharged from the system through pipe I94 controlled by valve I95. This isoparaflin fraction will contain material which is highly desirable, as discussed, for charge to the catalytic alkylation unit 95 and any portion desired for such reaction may be passed from pipe I92 through pipe I95 controlled by a valve I91. A normal paraiiin fraction may be separated from means I81 and returned to isomerization unit I84 through pipe I98 controlled by valve I99. Normal pentane from a separate source for treatment within the process'may be introduced to pipe I10 through pipe I59 and valve I09. Material so introduced may include recycled material from one or more of the conversion steps.

In some instances it may be desired to blend a portion of the normal pentane fraction directly in the finished gasoline product, in which case it may be passed from pipe I10 through pipe 200 controlled by a valve I to pipe I22. In case it is desired to subject a portion of the normal pentane fraction to isomerization or reforming in conjunction with other fractions of low octane number, a portion suitable for this may be passed from pipe 200 through pipe 202 controlled by valves 203 and 204 to pipe 201 passing to the reforming unit 208, to be described.

In many instances it will be found desirable to subject the hexanes and heavier fraction to a reforming operation to improve its octane num ber. When this fraction is shown-by analysis, as by careful fractional separation and testing of individual fractions, to be. comprised predominantly of hydrocarbons of low octane numbers, the entire fraction may be subjected to reforming by being passed from separating means II through a pipe 205 controlled by valve 205 to pipe 202 and through valve 204 to pipe 201 and reforming unit 208. In those'cases where it is not necessary to reform this hexanes and heavier fraction, or at least not to treat all of it in this manner, it may be passed from pipe 205 to pipe 202 and through valve 203 to pipe 200, and through valve 20I to pipes I22, and 255 for blendmany instances it will be found by suitable analysis that the hexanes and the heavier fraction will contain substantial portions of hydrocarbons of low octane number and substantial portions of hydrocarbons of high octane number, and that such portions may be advantageously separated from each other andonly the fractions of low octane number subjected to a reforming operation. In such a case the hexanes and heavier fraction may be passed from pipe 205 through a pipe 2I0 controlled by a valve 2 to a suitable separating means illustrated by a fractionating column 2I2. From the separating means 2 I2 there may be separated one or more fractions of low octane number and one or more fractions of high octane number. While the separating means 2I2 is shown as a fractionating column, it is to be understood that any suitableknown method of carrying outthe separation desired ior any particular hexanes and heavier fraction may be practiced, and in fact, many of the fractions may be more preferably separated by means of selective solvents which will separate aromatic or naphthenic hydrocarbons from paraflinic hydrocarbons. Such selectlve solvent extraction methods may, of course, be operated in combination with suitable fractional distillation units to effect the desired separations, as will be readily understood, and applied, by one skilled in the art. Material in the hexanes and heavier range from an outside source may be added, as desired, to the process through pipe 231 controlled by valve 238 to pipe 205.

In the present process fractions of high octane number are shown as being separated, from the material charged through pipe 2I0, by means of pipes 2I3, 2I4 and 2I5 controlled by valves 2I5, 2I1 and 2I8 respectively. Such fractions will comprise highly branched paraflln hydrocarbons, aromatic hydrocarbons, some of the lower boiling naphthenes, and/or the like. The fractions from. pipes 2 I4 and 2 I5 may be blended with the fraction in pipe 2I3 and passed through valve 2I9 to pipe 255 for subsequent blending in a finished gasoline product, or may be discharged from the system through pipe 220 controlled by a valve 22I. Selected fractions may be removed from the process as from pipe 2 through pipe 222 controlled by a valve 223, and from pipe 2I5 through pipe 224 controlled by a valve 225. Fractions of low octane number, primarily more or less straight-chain paraflins, may be removed from the material passing through pipe 2I0 through pipes 226, 221 and 228 controlled by valves 230, 23I and 232 respectively. fractions of low octane number may be blended together by being passed to pipe 201 and are subjected to a reforming in unit 208. Selected fractions for any suitable use may be removed from one or more of these streams as by being passed frompipe 221 through pipe 233 controlled by a valve 234, or from pipe 228 through pipe 235 controlled by a valve 236.

The material of low octane number passed through pipe 201 to reforming unit 208 may be treated in anysuitable manner to improve its octane number. This treatment may be carried out as an isomerization treatment under conditions similar to those described for the isomerization unit I84 or may be carried out by any suitable thermal reforming treatment at elevated temperatures and pressures.

However, we prefer to improve the octane number of this material by treating it in the presence of a catalyst under conditions such that there is a minimum of production of normally gaseous material or a minimum change in the boiling range characteristics of the material treated. Such a catalytic reforming may be carried out by passing the hydrocarbon stock over a suitable solid granular catalyst such as bauxite or other mineral materials, either alone or impregnated with suitable materials such as chromium oxide. For these operations the temperatures should be in the range of about 750 to 1100 F. preferably in the range of about 900-1050 F. under a pressure not substantially in excess of about pounds per square inch, preferably within the range of 5-30 pounds per gauge, and at a flow rate of about 0.5 to 5 liquid volumes of hydrocarbons charged per volume of space occupied by the granular catalyst per hour. Under these con- These ditions dehydrogenation and isomerization reactions take place with a minimum formation of light gases other than hydrogen. Free hydrogen may or may not be added to'the charge to such a treatment as by being introduced to pipe 241 by means not shown, as may be found desirable. Of the hydrocarbon gases produced the major portion is .C: and C4 unsaturated hydrocarbon material which can be subsequently'used in other steps of the process as will be described. For example, in such a treatment there was produced, for every barrel of hydrocarbon stock charged, about 247 cubic feet of C4 and lighter gases, which were predominantly free hydrogen and of which about 82 cubic feet comprised Ca and C4 hydrocarbons, of which over 70 mol per cent were oleilns.

The eiiiuent of the reforming unit 204 is passed through pipe 240 to a separation unit 2 which may include fractional distillation units and/or selective solvent absorption units as will be found most desirable. A reformed gasoline stock of high octane number is removed from separation unit 2 through a pipe 242 and is passed through a valve 242 to pipe 255 for blending with other stocks which are passed to pipe 255 to produce a finished motor fuel of gasoline characteristics and of high octane number. Any portion of the material passing through pipe 242 may be removed from the system through pipe 249 controlled by a valve 244. Light gases comprising primarily free hydrogen and methane and C1; hydrocarbons may be removed through the system through pipe 245 controlled by a valve 246. C: and C4 hydrocarbons, which will be predominantly unsaturated and highly suitable as a por-- tion of the charge stock to the catalytic alkylation unit 95, may be removed from separation unit 2 through pipe 241 controlled by a valve 248 and passed directly to pipe53. Any heavy undesired material may 25! controlled by a valve 25L A hydrocarbon stock-in the gasoline range of low octane number, or a portion of the stock passed through pipe 242, may be passed from separation unit 2 through pipe 252 controlled by a valve 253 to pipe 228 for subsequent retreatment in the reforming unit 205. When this recycle stock comprises a portion of the material removed through pipe 242 the result will be, after a steady state of operation has been reached, a higher octane number for the material passing through pipe 242. when selective solvent extraction is employed in the separation unit 24I, a separation may be readily accomplished between products of high octane number and unreacted material of low octane number, which latter can then be recycled through pipe 252 for retreatment.

A portion of the isopentane fraction produced in the thermal alkylation reaction zone 33 and removed from separation unit 42 through pipe 4'! may be passed therefrom through pipe 255 controlled by a valve 256 and blended with the reformed hexanes and heavier fraction passing through pipe 242. Other hydrocarbon fractions produced in the process and passed through pipes I, I5, I53, I62, I92, H3, 242, and/or I22, controlled by valves H0, 56, I54, I54, I93, 2I9 243, and I24, respectively, may be blended in pipe 255, to produce a motor fuel of gasoline characteristics as a final product of the process.

The reformed hexanes and heavier fraction and the catalytic alkylate will be the principal stocksof low volatility, and to these materials it is necessary to add one or more additional hybe removed through pipe scram":

drocarbon fractions of higher volatility to produce a finished motor fuel of gasoline characteristics- In most cases it will be necessary to add two or more of the other fractions described herein. Isopentane may be added directly from the separating means I I or may be added as a product of a process of the alkylation unit 33. The aromatic hydrocarbons produced in the aromatization of normal butane will be intermediate in volatility between the stocks of low volatility and stocks of high volatility. The neohexane fraction will be relatively high as to volatility and octane number, but will be low as to vapor pressure. Appreciable amounts of normal butane may be used directly as a result of the production of considerable quantities of a stock of extremely low volatility by the catalytic alkylation unit. When treating an initial stock charged through pipe II which contains appreciable amounts of sulfur compounds, they should be removed so as not to exceed the limits required by specifications for the final product. Most sulfur compounds present in the lighter fractions may be removed by simple alkali washes, carried out where necessary by apparatus not shown. The treatment described as preferred for the reforming unit 208 also converts the majority of the sulfur compounds which may be present in the hexanes and heavier fraction treated therein, and resulting hydrogen sulfide, or the like, is readily removed by suitable treatment such as an alkali wash, or distillation, forming a part of separation unit 2. Other known desulfurization operations may be carried out where suitable or necessary, as can be readily determined and applied by one skilled in the art.

It will be readily appreciated that our invention comprises combinations of process steps, each of which is separately known to the art, and that the accompanying flow sheet is diagrammatic only. some of the process steps are operated under quite high superatmospheric pressures, while others are operated under relatively low pressures, which may at times even be subatmospheric. For all of the process steps desirable operating conditions and ranges have been disclosed and discussed, and in all cases flows of materials treated and produced have been shown. The adaptation of our invention, or any particular modification thereof, to operation on a commercial scale with commercial epuipment such as pumps, compressors, heat exchangers,

heating units and furnaces, cooling catalyst chambers and reactors, separating equipment such as fractional distillation columns, absorbers, and solvent extractors, etc., may be readily made by one skilled in the art in view of the teachings of the present disclosure. Various modifications of our invention may be carried out without departing from the spirit of the disclosure or from the scope of the claims.

We claim:

1. A process for converting normally gaseous hydrocarbons having two to four carbon atoms per molecule into hydrocarbons boiling in the gasoline range, which comprises reacting propane with ethylene under noncatalytic alkylation conditions to form pentanes and recovering from eilluents of said alkylation an isopentane fraction so produced and containing a minor amount of olefins, separately reacting isobutane with ethylene under noncatalytic alkylation conditions to form hexanes and recovering from eflluents of the last said alkylation a hexane fraction so produced and an unreacted isobutane fraction containing a minor amount of oiefins, passing to a catalytic alkylation step said isopentane fraction and said unreacted isobutane fraction to react oleflns contained therein with said isoparaflins to form a normally liquid paraflinic fraction boiling aforesaid hexane fraction to produce a. gasoline of high octane number.

2. A multistage process for the conversion of substantially all of the natural gas hydrocarbons heavier than methane and boiling in and below the gasoline range contained in a hydrocarbon mixture recovered from a wet natural gas to a hydrocarbon material having gasoline characteristics, which comprises separating from a wet natural gas a fraction comprising ethane, a fraction comprising propane, a fraction comprising isobutane, a fraction comprising normal butane, a

fraction comprising a pentane, and a fraction in the gasoline boiling range of relatively low antiknock value and comprising heavier hydrocarbons, said fractions together comprising essentially all of the hydrocarbon material heavier than methane and boiling in and below the gasoline range originally in said wet natural gas, dehydrogenating said ethane fraction to form ethylene, reacting ethylene 50 produced with a portion of said propane to form predominantly saturated hydrocarbons comprising isopentane, separating from the effluent an isopentane fraction, dehydrogenating a further portion of said propane to form propylene, reacting said propylene, said isobutane, and said isopentane fraction from said alkylation in a catalytic alkylation step to form. predominantly saturated hydrocarbons in the gasoline boiling range of relatively high antiknock value, reforming said heavier fraction to increase the antiknock value thereof without materially changing the boiling characteristics, and blending said normal butane, said natural pentane fraction, said reformed heavier fraction, and said catalytic alkylate in the gasoline range to produce a composite hydrocarbon liquid having gasoline characteristics of boiling range, vapor pressure and volatility and having a high antiknock value.

8. A process for the production of a normally liquid hydrocarbon material of gasoline characteristics and relatively high antiknock value, which comprises separating from a natural gas a hydrocarbon material comprising substantially all of the hydrocarbons having two and more carbon atoms per molecule including normally liquid hydrocarbons in the gasoline boiling range and of relatively low antiknock value, separating from said hydrocarbon material an ethane fraction, a propane fraction, an isobutane fraction, a normal butane fraction, a pentane fraction, and a natural gasoline fraction in the gasoline boiling range of relatively low antiknock value, dehydrogenating said ethane fraction to form ethylene and recovering ethylene so produced,dehydrogenating said propane fraction to form propylene and recovering a propylene fraction so produced, reacting said ethylene with said isobutane fraction under noncatalytic alkylating conditions to form isomeric hexanes and recovering a resultant alkylate fraction in the gasoline boiling range and an unreacted isobutane fraction, dehydrogenating at'least a part of said normal butane fraction to produce butenes and recovering a butene fraction so produced, reacting said unreacted isobutane fraction, said propylene fraction and said butene fraction under catalytic alkylation conditions to form a catalytic alkylate and recovering a catalytic alkylate in the gasoline boiling range so produced, subjecting said natural gasoline fraction of low antiknock value to a catalytic treatment at elevated temperature to increase the antiknock value without essentially changing the boiling characteristics, recovering a reformed natural gasoline so produced, and blending said reformed natural gasoline, said catalytic alkylate fraction, said noncatalytic alkylate fraction, said pentane fraction and a portion of said normal butane fraction to produce a liquid hydrocarbon material having gasoline characteristics of boiling range, vapor pressure and volatility and of relatively high antiknock value.

4. A process for producing a balanced gasoline of premium characteristics from the ethane and heavier constituents of a wet natural gas, which comprises separating from a wet natural gas an ethane-propane fraction, an isobutane fraction,

and a natural gasoline fraction in the gasoline boiling range, said fractions together comprising eflluents an ethylene fraction, reacting said ethyl-,

ene fraction and said isobutane fraction under noncatalytic alkylation conditions to produce a noncatalytic alkylate comprising isohexanes and separating from the eilluent a noncatalytic a1- kylate fraction in the gasoline boiling range, reacting a portion of said normal butane fraction under aromatizing conditions to produce low boiling aromatics and separating from the eiiluent an aromatic fraction in the gasoline boiling range, separating by fractional distillation said natural gasoline fraction into a fraction comprising predominantly constituents of poor antiknock values and a fraction comprising predominantly constituents of good antiknock values, catalytically reforming said poor antiknock fraction to improve the antiknock value without materially altering the boiling characteristics and recovering from the eflluent a reformed natural gasoline fraction, and blending together said reformed fraction, said high antiknock natural gasoline fraction, said aromatic fraction, said noncatalytic alkylate fraction, said isopentane fraction, and a portion of said normal butane fraction to form a balanced gasoline of high antiknock value and containing all the hydrocarbon material obtained from the aforesaid fractions.

5. A process for producing a high yield of a liquid hydrocarbon I material having gasoline characteristics of boiling range and vapor pressure, and of relatively high antiknock value from a wet natural gas, which comprises separating from said wet natural gas to an ethane-propane fraction, an isobutane fraction, a normal butane fraction, a pentane fraction, and a hexane and heavier fraction in the gasoline boiling range, said fractions together comprising substantially all of the hydrocarbon material heavier than methane and boiling in and below the gasoline range originally in said wet natural gas, dehydrogenating said ethane-propane fraction to form ethylene andpropylene and separating from the eflluents an ethylene-propylene fraction so produced, re-' acting said ethylene-propylene fraction with said isobutane fraction under noncatalytic alkylating conditions to form low boiling normally liquid,

a normal butane fraction, an isopentane fraction,

predominantly parafllnic hydrocarbons and separating from the eifluents a noncatalytic alkylate fraction in the gasoline boiling range, so produced, subjecting at least a portion of said normal butane fraction to an elevated temperature and relatively low pressure to form low boiling, normally liquid, predominantly aromatic hydrocarbons' and separating from the effluents an aromatic fraction in the gasoline boiling range, separating said hexanes and heavier fraction into a fraction of high antiknock value and a fraction of low antiknock value, subjecting said low antiknock fraction to a catalytic reforming at elevated temperature to improve the antiknock value without substantial change in boiling characteristics, and recovering the resultant hydrocarbons in the gasoline boiling range, and blending said reformed fraction, said high antiknock hexanes and heavier fraction, said aromatic fraction and said alkylate fraction together with said pentane fraction and a portion of said normal butane fraction to form a liquid hydrocarbon material containing all the hydrocarbon material obtained from the aforesaid fractions and having gasoline characteristics of boiling range and vapor pressure and of relatively high antiknock value.

6. A process for producing a high yield of a liquid hydrocarbon material having gasoline characteristics of boiling range and vapor pressure and of relatively high antiknock value from a wet natural gas, which comprises separating from said wet natural gas an ethane fraction, a

. propane fraction, an isobutane fraction, a normal butane fraction, a normal pentane fraction, and

a hexane and heavier fraction in the gasoline boiling range, said fractions together comprising substantially all of the hydrocarbon material heavier than methane and boiling in and below the gasoline range originally in said wet natural gas, dehydrogenating said ethane fraction to form ethylene and recovering an ethylene fraction so produced, dehydrogenating a portion of said propane fraction to produce propylene and recovering a propylene fraction so produced, reacting a portion of said ethylene fraction and a further portion of said propane fraction under noncatalytic alkylating conditions to produce highly volatile normally liquid predominantly paraflinic hydrocarbons and recovering from the efiluents a pentane fraction so produced, reacting said isobutane fraction and a further portion of said ethylene fraction under noncatalytic alkylating conditions to form low boiling normally liquid predominantly parafllnic hydrocarbons and separating from the effluents a noncatalytic alkylate fraction in the gasoline boiling range so produced, separating also an unreacted isoparaflin fraction, subjecting said hexanes and heavier fraction to catalytic reforming at an elevated temperature to increase the antiknock value thereof without substantial change in boiling characteristics, separating a reformed fraction from the eflluents, separating also a C3-C4 fraction, subjecting in admixture said C3-C4 fraction, said unreacted isoparafiln fraction, said non'catalytie 'alkylate pentane fraction and said propylene fraction to catalytic alkylation to form a catalytic alkylate and separating from the eilluents a catalytic alkylate fraction in the gasoline boiling range, and blending said catalytic alkylate fraction, said noncatalytic alkylate fraction, said reformed fraction, and said normal butane and said normal pentane fraction to produce a normally liquid hydrocarbon material containing all the hydrocarbon material obtained from the aforesaid fractions and with gasoline characteristics of boiling range and vapor pressure and of relatively high antiknock value.

7. A process for the production of a motor fuel having gasoline characteristics of boiling range and vapor pressure and a relatively high antiknock value from a Wet natural gas containing normally gaseous hydrocarbons heavier than methane and normally liquid hydrocarbons in the gasoline boiling range, which comprises separating from said hydrocarbon mixture an ethanepropane fraction, a propane fraction, an isobutane fraction, a normal butane fraction, an isopentane fraction, 2. normal pentane fraction, a natural gasoline fraction boiling in the gasoline range of high antiknock value, and a natural gasoline fraction boiling in the gasoline range of low antiknock value, said fractions together representing substantially all the hydrocarbons originally in said wet natural gas heavier than methane and boiling in and below the gasoline boiling range, dehydrogenating said ethane-propane fraction to produce ethylene and recovering from eflluents of said dehydrogenation an ethylene fraction, dehydrogenating a portion of said propane fraction to produce propylene and recovering from efiiuents of said dehydrogenation a propylene fraction, reacting a portion of said ethylene fraction and a further portion of said propane fraction under alkylation conditions to produce highly volatile normally liquid predominantly paraffinic hydrocarbons and recovering from effluents of said alkylation a pentane fraction so produced, reacting a, further portion of said ethylene fraction and a portion of said lsobutane fraction under alkylation conditions to produce low-boiling normally liquid predominantly paraflinic hydrocarbons and separating from eflluents of said alkylation an alkylate fraction so produced and boiling in the gasoline range, separating also from eiiiuents of said alkylation an unreacted isoparaflin fraction, subjecting a portion of said normal butane fraction to aromatizing conditions to produce low-boiling aromatic hydrocarbons and also normally gaseous olefins by concomitant dehydrogenation reactions, separating from effluents of said aromatizing an arcmatic hydrocarbon fraction boiling in the gasoline range, separating also from said aromatizing a normally gaseous olefin fraction, subjecting said normal pentane fraction to catalytic isomerization to form low-boiling isoparaflins and recovering from effluents of said isomerization a low boiling isoparaifin fraction, subjecting said natural gasoline fraction of low antiknock value to reforming conditions to produce a stock of a higher antiknock value and substantially the same boiling characteristics and minor amounts of olefinic C3 and C4 hydrocarbons by minor concomitant cracking reactions, separating from efiluents of said reforming a reformed fraction boiling in the gasoline range, separating also from eiliuents of said reforming a C3-C4 fraction, subjecting in admixture said C3-C4 fraction, the aforesaid pentane fraction from said propane alkylation, said propylene fraction, the aforesaid unreacted isoparaffin fraction, a further portion of said isobutane fraction, the aforesaid low-boiL ing isoparailin fraction, and the aforesaid normally gaseous olefin fraction from said aromatizing to catalytic alkylation to form a catalytic alkylate, separating from efiluents of said catalytic alkylation a catalytic alkylate fraction boiling in the gasoline range, and blending said catalytic alkylate, said alkylate fractionfrom isobutane alkylation, said aromatic fraction, a further portion of said normal butane fraction, said isopentane fraction, said natural gasoline fraction of high antiknock value, and said reformed fraction to produce a normally liquid hydrocarbon material containing all the hydrocarbon material obtained from the aforesaid fractions and with gasoline characteristics of boiling range and vapor pressure and of relatively high antiknock value.

8. A process for the production of a motor fuel having gasoline characteristics of boiling range and vapor pressure and a relatively high antiknock value from a saturated hydrocarbon mixture containing normally gaseous hydrocarbons heavier than methane and normally liquid hydrocarbons in the gasoline boiling range, which comprises separating from said hydrocarbon mixture an ethane-propanefraction, a propane-fraction, an isobutane fraction, a normal butane fraction, a pentane fraction, a natural gasoline fraction boiling in the gasoline range of high antiknock value, and a natural gasoline fraction boiling in the gasoline range of low antiknock value, said fractions together comprising substantially all of the hydrocarbon material heavier than methane and boiling in and below the gasoline range originally in 'said wet natural gas, dehydrogenating said ethane-propane fraction to produce ethylene and recovering from efliuents of said dehydrogenation an ethylene fraction, dehydrogenating a portion of said propane fraction to produce propylene and recovering from efliuents of. said dehydrogenation a propylene fraction, reacting a portion of said ethylene fraction and a further portion of said propane fraction under alkylation conditions to produce hi hly volatile normally liquid predominantly paraflinic hydrocarbons and recovering from eilluents of said alkylation a pentane fraction so produced, reacting a further portion of said ethylene fraction and a portion of said isobutane fraction under alkylation conditions to produce low-boiling normally liquid predominantly paraiilnic hydrocarbons and separating from efliuents of said alkylation an alkylate fraction so produced and boiling in the gasoline range, separating also from emuents of said alkylation an unreacted isoparailin fraction, subjecting a portion of said normal butane fraction to aromatizing conditions to produce low-boiling aromatic hydrocarbons and also normally gaseous olenns by concomitant dehydrogenation reactions, separating from eflluents of said aromatizing an aromatic hydrocarbonfraction boiling in the gasoline range, separating also from said aromatizing a normally gaseous olefin fraction, subjecting said natural gasoline fraction of low antiknock value to reforming conditions to produce a'stock of a higher antiknock value and substantially the same boiling characteristics and minor amounts of olefinic C3 and C4 hydrocarbons by minor concomitant cracking reactions, separating from eilluents of said reforming a reformed fraction boiling in the gasoline range, separating also from effluents of said reforming a C3-C4 fraction, subjecting in admixture said C1-C4 fraction, the aforesaid pentane fraction from said propane alkylation, said propylene fraction, the aforesaid unreacted isoparamn fraction,

a further portion of said isobutane fraction, and the aforesaid normally gaseous olefin fraction from said aromatizing to catalytic alkylation to form a catalytic alkylate, separating from emuents of said catalytic alkylation a catalytic alkylate fraction boiling in the gasoline range, and blending said catalytic alkylate, said alkylate fraction from isobutane alkylation, said aromatic fraction, 9. further portion of said normal butane fraction, said pentane fraction, said natural gasoline fraction of high antiknock value, and said reformed fraction to produce a normally liquid hydrocarbon material containing all the hydrocarbon material obtained from the aforesaid fractions and with gasoline characteristics of boiling range and vapor pressure and ofv relatively high antiknock value.

9. A process for producing a high yield of a liquid hydrocarbon material having gasoline characteristics of boiling range and vapor pressure and a relatively high antiknock value from a wet natural gas, which comprises separating from said wet natural gas an ethane-propane fraction, a propane fraction, an isobutane fraction, a normal butane fraction, a pentane fraction, a natural gasoline fraction boiling in the gasoline range and having a high antiknock value, and a natural gasoline fraction boiling in the gasoline range and having a low antiknock value, said fractions together representing essentially all of the hydrocarbon material originally present'in said wet natural gas heavier than methane and boiling in and below thegasoline boiling range, dehydrogenating said ethane-propane fraction to form ethylene and separating from eiiiuents of said dehydrogenation ethylene so produced, reacting said propane fraction with a portion of said ethylene under noncatalytic alkylation conditions to form pentane and recovering from eflluents of said alkylation an isopentane fraction so produced containing a minor amount of olefins, separately reacting said isobutane fraction with the remainder of said ethylene under noncatalytic alkylation conditions to form hexanes and recovering from effluents of the last said alkylation a hexane fraction so produced and an unreacted isobutane fraction containing a minor amount of olefins, passing to a catalytic alkylation step said isopentane fraction and said unreacted isobutane fraction to react olefins containing therein with said isoparaillns to form a normally liquid parafiinic fraction boiling in the gasoline range, separating from eflluents of said catalytic alkylation a gasoline range fraction so produced, subjecting a portion of said normal butane fraction to an elevated temperature and relatively low pressure to form low-boiling normally liquid aromatic hydrocarbons and separating from eifluents thereof an aromatic hydrocarbon fraction in the gasoline boiling range so produced, subjecting said natural gasoline fraction having a low antiknock value to reforming conditions to produce hydrocarbons having rela tively high antiknock value and separating from eflluents of said reforming a reformed fraction boiling in the gasoline range and of relatively high antiknock value so produced, blending said fraction from catalytic alkylation, said hexanes and heavier fraction from said noncatalytic isobutane alkylation, said aromatic fraction, a further portion of said normal butane fraction, said pentane fraction, said natural gasoline fraction having a high antiknock value, and said reformed fraction to produce a normally liquid hydrocarbon material containing all the hydrocarbon material obtained from the aforesaid fractions and boiling in the gasoline range, and having gasoline characteristics of boiling range and vapor pressure and having a relatively high antiknocl: value.

GEORGE G. OBERFEIL. JEAN P. JONES.

Images