US2414205A - Production of motor fuel - Google Patents

Description

' Jan. 14, 1947. E. H. LANG PRQDUCTION oFI MOTOR FUEL Filed June 4, 1941 INVENT OR.

No, @aw

Patented Jan. 14, 1947 UNITED STATES PATENT OFFICE- 2,414,205 PRODUCTION oF Moron FUEL Edward H. Lang, Chicago, Ill., assignor to The Pure Oil Company, Chicago, Ill., a corporation Application June 4, 1941, Serial No. 396,495

2 Claims.

' This invention relates to production of motor fuel. I

Various methods are known for converting hydrocarbon oils and gases into motor fuel. The methods which are in common usage are thermal c'racln'ng of oils at high temperatures and thermal orcatalytic polymerization of hydrocarbon gases. Reforming of low octane naphtha either with or without catalyst is also commonly practiced. In all these methods the resulting product is highly unsaturated or olenic.

Experience has shown that highly olenic motor fuels have certain disadvantages. First7 their susceptibility to lead is low as compared with parainic hydrocarbons. Moreover, under high speed operating conditions olenic hydrocarbons have a tendency to cause knocking in modern automotive engines of high compression ratio.

The object of this invention is to provide a method for producing a Well-balanced motor fuel which performs without knocking at all speeds.

Another object of this invention is to provide a method for treating a mixture of hydrocarbons boiling within the gasoline range and containing a high percentage of olenic hydrocarbons, to produce a well-balanced motor fuel.

Still another object of this invention is to' provide a method for converting hydrocarbon oil into motor fuel which gives a high road performance test.

A further object of the invention is to convert hydrocarbon gases into motor fuel which gives a high road performance test.

Still a further object of the invention is to provide a method for improving performance of motor fuels by proper treatment of particular fractions and reblending of the fractions after treatment. I

Other objects of the invention will become apparent from the following description and the accompanying drawing of which the single figure is a diagrammatic elevational view of apparatus suitable for carrying out the invention.

Referring to the drawing, numeral I indicates a line through which fresh oil is fed to the unit. The fresh oil may be gas oil, kerosine or naphtha or it may be residuum where it is desired to practice vis-breaking. The fresh oil is fed into the upper portion of the absorber 3 where it passes in countercurrent contact with hydrocarbon gas which enters the bottom of the absorber through the line 5. The absorber is maintained under suitable pressure which may vary from 100 to 400xpounds per square inch and the temperature is maintained in the absorber at approximately 'I0-90 F. In the absorber substantially all the C3 and heavier hydrocarbons are absorbed from the gas together with minor amounts of lower boiling gases. The unabsorbed gas consisting primarily of C1 and C2 hydrocarbons together with a small amount of hydrogen and higher boiling hydrocarbons, leaves the top of the absonber through the line 'I controlled by valve 9.

The fat oil, i. e., charging stock containing dissolved therein hydrocarbon gases, leaves the bottom of the absorber through line I I, passes through heat exchanger I3 and is then pumped by means of pump I4 through heating and reaction coil I5. The fat oil may be heated in its passage through coil I5 to a temperature of from 900 to 1150o F., depending upon the nature of the oil. `Where residuum stock is being treated, the temperature will be in the neighborhood of 9007 F. Where the process is used for conversion of naphtha, temperatures approaching l F. may fbe used and where stocks boiling intermediate between residuum and naphtha are processed, temperatures will be intermediate between 900 and l150 F.

rhe fat oil is forced through coil I5 at a pressure which may vary from approximately 500 to 3000 pounds per square inch and the time of residence in the coil I5 is sufficient to obtain the desired amount of conversion. The nature of the reaction in the coil I5 is rather complex. Cracking of the oil and gas takes place concurrently with alkylation and polymerization. Because of the high temperatures to which the products are subjected in the coil I5, the resultant-products are highly unsaturated. The olefinic content of the reaction products may be 35 to 50% or more.

The reaction products leave the coil l5 through valve I1 where the pressure may be reduced to 500 pounds per square inch or less, pass through heat exchanger i3 where the temperature is reduced to approximately 350 to 550 F. by indirect heat interchange With the charge to the coil I5 and then pass into the lower portion of the fractionating tower I9. The temperature to which the reaction products are reduced prior to entering the fractionating tower will depend largely on the nature of the charging oil. With heavier charging stocks the temperature of cooling should be close to 550 F. in order to avoid partial condensation in the heat exchanger with resultant coke deposition, With lighter charging stocks the dew point of the reaction products is considerably lower and therefore lower cooling temperaturesmay beused.`

In the fractionating tower separation ofthe reoline. withdrawn through line 5l, condensed in cooling action products into residuum, recycle stock, heavy gasoline distillate, light gasoline distillate and gas takes place. The residuum is withdrawn through line 2l controlled by valve 23 and it may be discharged from the system and used `as fuel oil. The recycle stock which is heavier than the gasoline distillate is withdrawn from the tower through line 2t and may be recycledto the absorber through valve 25, line 2'6, cooling coil 21 and line 29, or may be withdrawn from the system through line 3l controlled by valve 33, or may be charged by means of line 35 and pump 36 either to the reaction coil l5 or through cooling coil 3l and line 38 to line 3i! to act as quenching liquid for the reaction products, where temperatures lower than those resulting from the eX- changer I3 are desired. It will be apparent that the recycle stock may be divided in any desired manner. Uncondensed gas is withdrawn from the top of the fractionating tower through line 4D controlled by valve lli, and cooling coil 42, and charged to absorber 3.

The heavy gasoline distillate is withdrawn from the fractionating tower through line G3 controlled by valve fifi. This distillate may have an initial boiling point of between v200" to 250 F. and an end boiling point of approximately 400 F. The boiling range of this vfraction may vary somewhat, but in any event it should be within the upper gasoline boiling range. passes to the reactor or reaction chamber El5 containing anhydrous aluminum chloride `preferably vdeposited'on a solid comminuted material such as silicaor fullers earth. If the vdistillate is not sufficiently warm kas it Venters the reaction chamber 125, the reaction chamber may be heated to bring .the temperature up to approximately IOW-250 F. Ordinarily, the distillate will be sufficiently warm as it leaves the fractionating tower so asnot to require additional heating. As the heavy gasoline distillate enters the aluminum chloride reaction chamber it is mixed with methyl and/or'ethyl chloride which enter the gasoline stream through line t. In the presence of aluminum chloride these chlorides react with the gasoline insuch manner as to alkylate the unsaturated hydrocarbons contained therein to V:form saturated iso-paraflins. The reaction products leave the reaction chamber #l5 through line A1, pass into separator i8 where the liquid hydrof carbons are separated from the gases which may consist of hydrogen chloride,V chlorine and unoonverted hydrogen and hydrocarbon gases. The liquid hydrocarbons are mixed with the light gasoline ydistillate which is withdrawn from Yfrac- -tionating tower i9 through line 49 controlled by valve 5i and the blend is'passed through line 53 into fractionator 55 Where it is subjected to heating and fractionation to separate end point gas- The gasoline vapors pass overhead, are

coil 59 and collected in receiver` El. The heavy vends are withdrawn from the fractionating tower through line 53 controlled by valve 55 and may be recycled for further conversion.. [The gasoline distillate may be given a caustic wash or other Vsuitable treatmentjif necessary to remove any traces of chlorine or hydrochloric acid which remain therein.

The alkylation reactionv in the reactor t5 may take place --at vatmos'plieric -or superatmospheric *pressure but itis preferably carried `out at pressures ofV the order of 100 vto S50-pounds per square inch. Higher pressures may lbe --us'edif desired. ArEhe gases from-separator 48 laveithe top there- The distillate .ed controlled by valve 93.

i of through the line 61 and are mixed with air which enters the line 6l through line 69. The mixture then passes into the chlorine regenerator 'H which may contain a saturated cuprous chloride solution on pumice. In the presence of the cuprous chloride the air oxidizes the hydrochloric acid, liberating chlorine. The chlorine regenerator should be heated to a `temperature below 7 50 F. but sufficiently high to cause the reaction to take place. The reaction products leave the regenerator 'H through line 'i3 and pass into washing tower and separator l5. Water vapor and hydrochloric acid may be washed fromthe entering gases by means of water fed into the upper portion of the tower through the line 11.

[The wash water is withdrawn from the bottom of the tower through the line 19 controlled by valve 8l. By maintaining the separator 'l5 under superatmospheric pressure, the chlorine can be liquefied in the upper portion of the tower and ,separated fromthe remaining gas such as nitrogen, oxygen and hydrocarbons which escape from 4the'top of the tower through the line 83 controlled by valve 85. Chlorine is withdrawn from the separator 'l5 through line 8l controlled byvalve 89 and recycled through line 'I where it is mixed with the vC1 and C2 hydrocarbons from the absorber. The mixture then'passes to the reactor iii in which chlorine is combined with the C1 and i C2 hydrocarbons to -form chlorides of these hydrocarbons, Make-up chlorine is added through line Reactor 9i may be maintained under atmospheric pressure or under superatmospheric pressure somewhat lower than that maintained in the separator 'l5 and may be cooled to control the reaction. The reaction products are withdrawn from the reactor 9i through line 9d, compressed by means of compressor95 and used to alkylate the heavygasoline Y distillate in the reaction chamber-45.

Instead of chlorinatingthe C1 and C2 gases from absorber 3,these gases may be withdrawn Vfrom the system through'line d6 controlled by valveille'and methane and/or other paraiinic gas fronran independent source fed through line 98 controlled by valveSQ to chlorinator 5I. Moreover, methyl chloride tromV an Vextraneoussource caribe charged through line riiii) controlled by valve iti to the aluminum chloride reactor'd and the necessity of chlorinating methane and/or .ethane as part of the process, dispensed with.

It will "oe seen, therefore, that I have devised a unitary process for converting hydrocarbon oils and gases into a finished gasoline, the light fractionY of which is 'high in unsaturates and the heavier `traction of which is high in. saturated hydrocarbons and 'contains very little unsaturated hydrocarbon. The light fractionV will consistfpredcminantly of olefinic hydrocarbons with ASonie 'arorr'iatic' hydrocarbons'. Thearomatic hy- 'fdrocarbonsin therli'ght fraction are unobjectionvable 'since-'they appear to 'be 4vbeneiicialfor'low speed operation. AIn the heavy fraction of the `gasoline willfbe-.present isoparaiins formed by the allai/lation of the aliphatic unsaturated hy- `drocarboneand. some aromatic 'hydrocarbons con- Ataining alkyl side' chains. .The presence of` alkylated ybenzene and-aiicyclic hydrocarbons in the high 4boilinglfrvalction'is not yobjectionable since they-'appear to'actflilze paranic `hydrocarbons and? therefore are beneficiall for high-speed `performance'.

Although I have shown Land-disclosed ymym- Vventiovn. in connection V.with aljpolyformlsprocess for producing unsaturated gasolinedi'stillates:and

a Friedel-Crafts type of process for saturating the heavy gasoline fraction, it will be understood that the invention is not limited to these specific steps. The invention in its broadest aspects covers the saturation of a higher boiling gasoline fraction rich in oleiinic hydrocarbons and the blending thereof with a lower boiling highly unsaturated gasoline fraction, regardless of the manner in which the saturation is effected. For example, saturation may be eiected by hydrogenation` with hydrogen under pressures of the order of 800 pounds per square inch at temperatures of the order of 350-400 F. in the presence of a catalyst, as, for example, one composed of copper, magnesium oxide and zinc oxide. The highly unsaturated low boiling gasoline fraction may be prepared by either thermal or catalytic polymerization of hydrocarbon gases or by thermal reforming of naphtha at temperatures of the order of 1000-1050 F., or catalytic dehydrogenation of naphtha at temperatures of the order oi 'TSO-950 F. in the presence of a catalyst such as Activated Alumina impregnated with chromium oxide. The method and apparatus describe and show one way of accomplishing the objects of my invention.

The invention accomplishes the object of mproving road performance of motor fuel without the necessity of increasing octane rating as measured by the A. S. T. M. method. Motor fuels produced in accordance with my invention will perform better than motor fuels of equal or even higher octane number prepared by Well known methods.

It Will be understood, however, that although the invention relies on modifying the nature of the compounds in the upper boiling fraction in order to obtain the desired motor fuel, not on the necessity of increasing the octane number of the fuel, in accordance with my invention the octane rating of the fuel as measured by the A. S. T. M. method is in fact increased without suffering any decrease in yield of motor fuel. Alkylation or hydrogenaticn of the upper boiling fraction results in increased octane rating thereof and in an increased amount of liquid product within the motor fuel range.

I claim:

l. The method of preparing motor fuel. which comprises charging e. mixture of hydrocarbon oil and gas to a conversion Zone, subjecting the mixture in said zone to conditions of time, temperature and pressure to convert a substantial portion thereofinto unsaturated hydrocarbons boiling Within the gasoline boiling range, separating from the reaction products a fraction boiling within the upper gasoline boiling range, separating the reaction gases into a fraction containing predominantly C3 and higher boiling hydrocarbons and a fraction containing predominantly C1 and C2 hydrocarbons, recycling the C3 and higher boiling hydrocarbon fraction to the conversion Zone, converting the C1 and C2 hydrocarbons to alkyl chlorides, alkylating the fraction boiling within the upper gasoline range by means of said alkyl chlorides in the presence of aluminum chloride and blending with the alkylated fraction the hydrocarbons rich in unsaturates, boiling within the lower gasoline boiling range.

2. The method of preparing motor fuel which comprises converting hydrocarbon oil into hydrocarbons rich in olenes boiling within the gasoline boiling range and into hydrocarbon gases having from 1 to 4 carbon atoms per molecule, chlorinating C1 and C2 gases to alkyl chlorides, alkylating the higher boiling portion of the gasoline boiling range hydrocarbons by means of said alkyl chlorides in the presence of aluminum chloride, and blending the resulting alkylate with the lower boiling gasoline boiling range olelnic hydrocarbons.

EDWARD I-I. LANG.

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