US1235523A - Process of treating oils. - Google Patents

Description

Y A. IVI. McAFEE.-

PROCESS 0E. TREATING oILs.

APPLICATION FILED SEPT. 30. 1943.

1,235,523.. Patented July 31, 1917.r N l 1 lmamntoz Uff/66 X1I. A 1

4ALIllIER M. MCAFEE, 0F BAYONNE, NEW JERSEY.

PROCESS OF TREATING- OILS.

Application filed September 30, 1913.

To ZZ whom/t may concern.'

Be it known that I, ALMER MoDUrrm MCAFEE, a citizen of the United States, residing at Bayonne, in the county of Hudson and State of4 New Jersey, haveinvented certain new and useful Improvements in Processes of Treating Oils, of which the following is a specification.

This invention relates to process of treating oils; and it comprises a process of obtaining a substantially complete catalytic conversion of higher boiling petroleum oils into lower boiling oils and in particular of converting high boiling oils, distillates and residua into gasolene solvents and kerogene, or into gasolene alone wherein a body of such high boiling oil is heated in a slow and regular manner in the presence of a catalytically-acting metal, best aluminum, while a current of chlorin or chlorin-containing gas such as hydrochloric acid gas, is introduced into said body, the low boiling products of reaction and the hydrochloric acid produced being removed continuously during the progress of the reaction, and the volume of said body of oil being kept substantially constant by the addition of fresh oil from time to time, or continuously; all as more fully hereinafter set forth and as claimed.-

As thev low boiling petroleum oils of the natmeof gasolene, solvents (distillates used as substitutes for turpentine, for eX- tracting grease, etc.) and kerosene are of considerably higher market value than the higher boiling residua and fractions, such as lubricating oil, gas oil, etc., there has long been an effort in the art to increase the amount of low boiling material at the eX- pense of the higher. To this end, in order to secure more gasolene and kerosene than are naturally contained in the crude petroleum, it is customary to crack the oil more or less; the high boiling portions of the oil are heated to a high temperature to break down such portions to form low boiling oils. Generally this cracking is done under pressure. There is however a limit to the additional amount of low boiling oils such as gasolene and kerosene which can be recovered from petroleum by these cracking processes, since a high degree of cracking is apt to produce too much gas, tar and coke. For this reason 'cracking is not generally carried beyond the point lof obtaining l0 to 20 per cent. of additional low boiling oil. The re- Specication of Letters Patent.

tively low commercial grade.

Patented July 31, 1917.

Serial No. 792,616.

'sidual oils, or distillates left after the cracklng operatlon are utilized as gas oil, parailin oil, fuel oil, etc.; all materials of comparay Practically no method of obtaining increased yields of low boiling oils from petroleum other-than by this cracking operation is in use. The

'cracked gasolenes and kerosenes so obtained are of vlow grade, having a foul odor and. tending to burn with production of smoke and soot. Being largely composed of the unsaturated compounds produced in cracking it 1s not economical to rene them Vwith lacid to any extent as the 'loss of oil and consumption of acid would be too great.

YI have found that by taking any petroleum high boiling oil, whether a crude oil,

a distillate or a residuum, and suspending in it a finely powdered catalytic metal, (best aluminum) heating to a relatively'moderate temperature and introducing chlorin, I can secure a breaking down, of the complex hydrocarbon molecules into simpler molecules of the order of those found in gasolene, solvent oils and kerosene; there being a substantially complete conversion of high boiling oils into low-boiling oils without a wasteful production of low grade by-ploducts. By. suitable regulation of conditions the higher boiling oils can be converted into gasolene alone. The amount of metal necessary is quite small. Most of the chlorin introduced reappears as hydrochloric acid gas which may be condensed and utilized. In this reaction the low boiling bodies or oils produced appear to be completely or substantially, of saturated nature and are therefore of high grade. They do not contain any chlorin.

The best metal which I have found for my purposes is aluminum, although zinc and iron may be used. Their use however, at least with the majority of oils, is much less advantageous than that of aluminum and I shall hereinafter speak more specifically of aluminum. Instead of chlorin, bromin may be employed, but its use presents no advantages. On the other hand, hydrochloric acid may be used in lieu of chlorin; in fact in certain relations its use seems to be more advantageous than thaty of chlorin. The use of both is often convenient, since as the chlorin led into one apparatus reappears as hydrochloric acid, this acid may be used in another apparatus operating in parallel. Generally somewhat higher temperatures are advantageous in working with hydrochloric acid.

While any commercial form of finely comminuted aluminum is useful, l prefer the grade known as aluminum bronze powder, as it is fine, light and readily distributed through the oil and presents enough surface to enable stirring apparatus to keep it in a state of uniform suspension. Aluminum ilings, chips, etc., are not so advantageous. Either the commercial hardened aluminum containing a little Zinc or pure aluminum may be used. W'here pure aluminum is available it is sometimes a convenient expedient to grind up lilings or chips of it with coke or the like, as this gives a largesurface to the aluminum; the soft aluminum spreading over and covering the surface of the granular material. Aluminum amalgam may be employed and is particularly active. Instead of the metallic aluminum, other aluminous material such as dry but reactive forms of alumina may be employed, such as the dried but unignited hydrate, and particularly where hydrochloric acid is used.

The operation is or may be, conducted in a continuous manner; and in practice l prefer to so conduct it, as it enable me to keep l the oil in the apparatus of constant compo sition and at substantially constant temperature; a temperature best adapted for catalysis. To this end l may establish and maintain a body or mass of hot or boiling liquid oil of substantially constant volume and temperaturein a suitable still or the like, said body of oil containing the powdered metal which is kept in suspension by vigorous agitation. This agi tation is necessary both for suspension and to maintain the contents of the still homogenous. The chlorin is led into contact with this oil. From the hot body of oil under treatment l withdraw vapors of the low boiling products formed as fast as produced, the vapors being continuously drawn off in any suitable way and condensed. This is to remove the low boiling bodies from the iniiuence of the catalytic operation, thereby preventingtheir being further broken down into gas and worthless products. And to maintain uniformity of conditions in the sphere of reaction by maintaining constant volume, l continuously replenish the body of oil in the still by feeding in fresh oil at a rate corresponding to the withdrawal of the low boiling vapors.

Petroleum oils, and particularly the high boiling oils, are materials of complex nature, containing many constituents and while these do not all react in the present operation with the same ease or the same speed yet under the described conditions any diilicultly reacting body is simply retained in the still until it is converted and removed. 'lhe charge or" oil in the still is, so to speak,

:instaan a dominant pool averaging out the irregularities of composition in this respect.

The time factor in this operation is an important one. rlhe body of oil should be relatively large as compared with the amount fed in and the amount distilled od' in a time unit. This insures ample time for the treatment of refractory constituents of the oil. A good rate of distillation for the present purposes is such that 12 hours or more are required to form a volume of distillate corresponding to the volume in the still. Stated in another way, the amount of distillate going over in four hours or more may amount to about a third of the volume of the body of oil maintained in the still. ln continuous distillation Where `the volume of oil in the still is maintained constant by the intlux of fresh hot oil, refractory portions of the oil may remain in the still under the influence of the catalyst for two or three days. The heating, distillation and other conditions should be so controlled as to spread the period of high activity of a charge of catalyst over at least 48 hours. The temperature to .be maintained in the oil body during the operation should be as uniform as possible, but the particular degree will depend somewhat upon the particular oil being treated. After adding a charge of catalyst, the temperature may advantageously be allowed to ascend a little during the period in which such charge is in use, being slightly higher toward the end of the activity of such charge than in the beginning. With high boiling oils such as gas atA eeA

oil, lubricating oil, still bottoms, etc., nori mally boiling at or above 600o F., the average temperature in operation is very advantageously around 500 F. With such oils 600 F. may be stated as an extreme temperature, and around 500 F. as the best temperature. At 500 F. there is little or no danger of the ordinary type of cracking distillation taking place while with most of these oils under the conditions of the present operation there will be lively ebullition and distillation. The gasolene, solvent oils and kerosene formed by the catalysis of course boil or vaporize freely from the heavy oil around 500o F. The catalytic action on the extremely high boiling oils at temperatures below 500 is slow. Above 600 there is apt to be too much evolution of vapor while there is also danger of cracking distillation taking place simultaneously with the catalytic reaction. Cracking is not desired in the present invention. With low boiling oils, such as spindle oils, kerosene, etc., the catalytic action is quicker and takes place at a somewhat lower temperature. The still should be well heat insulated as a rule to promote uniformity of temperature conditions therein, but prior to allowing the vapors produced to go to the condensing arfor condensation and return of heavy boiling vapors for a reflux of condensate of high' boiling oil. This is also useful as preventing the passage of volatile aluminum-oil compounds into the condenser with production of stoppage. As a rule, the temperature of the vapors at the point of exit from the distilling and refluxing apparatus should not exceed 350 F. and for certain purposes should not exceed 300 F. If the exit temperature be around 350 the vapors and condensate will contain gasolene, solvent oils and kerosene. Solvent oils in petroleum distillation are the grades of distillate marketed for use in varnish and the like as substitutes for turpentine and sometimes known as turpentine substitute. If it be around 300 F., the vapors and lcondensate will be substantially all gasolene. By dropping the temperature of the exit vapors a little below 300 F., low-boiling, very uniform gasolene may be obtained.

Whatever the speed of distillation, the heating conditions should be so controlled as to keep the body of oil as free as possible of these products, distilling them olf as fast as formed. As soon as produced the gasolene, etc., should be removed from the influence of the catalyst. This is one of the reasons for keeping the body of oil in constant ebullition.

All material and apparatus used should be dry. The oil treated should be tirst heated for a time to free it of moisture prior to introducing metal and chlorin and the -replenishing oil fed into the still should be similarly hot and dry. Anymoisture present or gaining access to the still causes irregular reactions and a waste of reagents. The chlorin or hydrochloric acid employed `should be as dry as possible.

The chlorin or hydrochloric acid gas may be fed into the still in any convenient way as by a duct leading into the still and ending under or above the surface of the oil body, or by introducing the chlorin together with the supply of fresh oil. Where a chlorin conduit ends in proximity to the oil it is generally advantageous to feed the chlorin under considerable pressure to blow out any plugs of carbon, tar, or the like which may tend to stop such conduit. However, the conduit may be so shaped or dimensioned as to make plugging unimportant.

While any type of still may be employed, the ordinary cheese-box type of still made of iron, steel or other convenient material, is advantageous. It may be insulated against escape of heatand should be provided with readily controllable heatingori firing means. The vapor conduit leading from the still should be cooled at one point, as by air cooling, and provided withmeans for returning any condensate occurring at this point back to the still. Beyond the cooled portion, the vapor conduit may lead to the usual condensing arrangement employed in other distilling operations. The temperature of the cooled portion may be regulated as desired. If the temperature of the vapors here be, as is desirable, not above 350o F., the distillate may be condensed as 'a whole andthe gasolene, etc., separately regained by fractionation; or such distillate may be led through the usual condensing arrangements and each grade regained separately. Bv maintaining the temperature in the cooled portion of the vapor conduit having reflux connection .around 300 F., so that the vapors go to exit at 300 or below, the distillate will be substantially lall gasolene. The temperature and composition of the oil in the still should be kept as uniform as possible and the provision of stirring arrangements contributes to this end as do the continuous removal of low boiling oils and addition of fresh oil in the manner described.

"While the described process is not in any way dependent on any particular type of apparatus, and indeed may be performed in any of the usual stills, I have shown more or less diagrammatically, an apparatus of a type I have used with advantage in the conversion of oils with production of secondary gasolene. In this showing the ligure is a central vertical section (partly in elevation) of a single still and accessory parts.

Element 1 designates the still proper, as a whole.` Oil may be introduced throughl valved inlet 2 and withdrawn through valved outlet 3. Firing means are diagrammatically shown at 4. At the top,'the still is provided with top 5 carrying stirring means 6. In a small sized still the whole top may be removable. Passing through the cover is vapor outlet 7 leading to chamber 8. Vapor line 9 leads from this chamber to air cooled condensing chamber 10. As shown, this is of simple cylindrical de'- sign; but any other type of air cooled condenser may be substituted in its stead. From this condensing chamber vapor conduit 11 leads to another and similar condensing chamber 12. Beyond this chamber is vapor conduit 13 carrying thermometer 14 and provided with valve 15. Beyond the valve this conduit connects with condenser or cooling device 16, shown diagrammatically as a series of connected pipes in tank 17, adapted to hold water or other cooling iuid. At the base of the first air condensing chamber is outlet 18 connected to reflux.. conduit 19. As shown, this reflux conduit has a portion 20 at a lower level to serve as an oil trap. Connected to this reflux conduit is outlet 21 for the second air cooled condensing chamber. Valve 22 allows communication between the outlet and the reflux conduit to be closed or opened at pleasure. Connected to 21 above this valve is valved outlet conduit leading to coil 24 shown as located in the same cooling tank as 16. Manhcle 25 may be provided in the top of the still for introducing aluminum and for other' purposes. Inlet 26 having a depend-` ing leg 27 may be provided for the purpose of introducing` chlorin or hydrochloric acid into the charge.

1n the use of this structure, a suitable charge of crude oil may be introduced through inlet 2 and heated until thermome- -ter 14 shows a temperature between 300 F.

and 35001?. At this time the oil is free of water. Aluminum in the desired amount may now be introduced through manhole 25 and the heating continued, clilorin being led in through pipe 26. An evolution of vapors of low boiling oils at once begins and passes upward past 8 through 9 into 10. vChamber 8 serves to retain and return any suspended matter, etc.7 that may be carried up mechanically or otherwise. 1n 1G, vapors are more or less cooled and such oil as is condensed passes downward through 18 into 19, depression 20 serving as an oil trap. Uncondensed vapors go forward through 11 into 12 where a further condensation takes place. Valve 23 being closed and valve 22 open, condensate in this chamber returns or refiuxes through 2O and 19 to the still. lVith thermometer 14 standing at 300" F. to 350O F., vapors passing forward to and condensed in 16 will be gasolene. This gasolene may be fractionated in any way and in any suitable apparatus. Where it is desired to make two cuts in this distillation, valve 22 may be closed and valve 23 opened. In this event, high boiling oils condensing in 10 reflux back as before While such oils as condensed in 12 instead of going back to the still pass beyond 23 into coil 24C. When making two cuts in this manner, the gasolene condensed in 16 needs no further redistillation. The product collected from 24 will be solvent and burning oils or either' according to the temperature in condenser 12.

As described, 1 have stated a discontinuous operation but in practice 1 operate continuously or until the charge of metal in the still becomes exhausted. For this purpose there is a feed of fresh hot oil through 2 in amounts corresponding1 to the volume of, distillate appearing at 16 and 24. Fresh metal may be supplied from time to time through 25. YVhen it is desired to clean out the still this may be donei by means of 3 and 25.

While for the sake of simplicity of illustrati on I have shown but two air-cooled condensers used in series and have shown means for collecting` but two cuts and ;have shown these elements as of a simple type, it will he obvious that any number of condensers messes may be used in series and that they may be of any type. The condensers may be cooled in any other way in lieu of being simply air cooled as shown.

1t will be observed that temperatures used in the present invention are all below the usual cracking temperatures of 650O F. and higher. No cracking7 in the usual sense, is desired in the present process. Pressure may be employed but is not necessary.

rlhe kerosene and solvent oil fractions, where produced, may be retreated with metal and chlorin in the same manner to furnish more gasolene, or they may be marketed directly.

The described process is applicable to any petroleum oil, distillate or residuum. 1t enables a good utilization of gas oil, fuel oil and the like. Kerosene made in this manner, or in any other-manner, may be converted into gasolene by the present process7 as may spindle oils.

The proportion of aluminum necessary is not large and it apparently maintains its activity in this process for a considerable length of time, 2 or 3 days of continuous distillation at least. For most oils less than 1 per cent. of powdered aluminum (reckoned on the amount of oil temporarily in the still) is an eicient amount. Toward the end of the activity of a charge the aluminous material is contained in a granular coky mass which settles out of the oil whenever stirring is discontinued and which may be treated to regain aluminum or aluminum compounds.

ln continuous operation, this granular coky mass7 or portions of it, may be removed from the still from time to time and replaced by corresponding amounts of fresh metal. Ur new catalyst may be addedto the still without removing the old, and this repeated till the accumulation of solid matter becomes inconvenient. As it deposits readily. being substantially free of tar, resin or gum, it is not necessary to remove the whole body of oil from the still or clean the still in changing catalyst; though of course either may be done. The time when a change of catalyst is necessary may be readily observed by a diminution of the flow of low boiling condensate.

TVhere sulfur containing oils are to be treated no preliminary purification is necessary as the process itself evolves and re,- moves sulfur in the form of HES, but in oils where the amount of sulfur bodies occurring is high it is often better to give the oil to be converted into gasolene a previous treatment with acid to remove some of these sulfur bearing compounds. This treatment will also remove moisture. The removal of sulful enhances tl1e`.pei'iod of activity of the catalyst and is therefore advantageous.

ly the described process l have converted sol gas oil and similar oils into gasolene .with about an 85 per cent. conversion. About 10 per cent. of the oil 'is converted into gas which may be used for heating purposes and the residue forms granules of coky carbon.

As to the rationale or mechanism of the reactions occurring in the still in the described process, I cannot say, contenting myself with noting the operations performed and the results obtained. It may bethat some of the catalytic action is due to the direct production of aluminum chlorid in the body of oil, or it may be that the action of the aluminum on the oil in this operation is direct. I may say, however, that the aluminum appears to exercise more catalytic activity in this process than would result from the corresponding amount of aluminum chlorid.

AS stated zinc or iron may be used in lieu of aluminum but are less advantageous. When used, they are employed in the same manner as aluminum. Using alumina, it may be introduced through 25 and hydrochloric acid gas led in through 26. This gas may come from a previous apparatus (not shown) using chlorin.

In another and copending application Serial No. 7 92,615, filed concurrently herewith, I have described and claimed another method of making low boiling oils from high boiling oils in which the high boiling oil is heatedto its boilin point in the presence of aluminum chlorid and the low boiling oil formed is condensed and removed while high boiling oil and vapors of aluminum chlorid are returned to the still. In this ap-v plication the claims are drawn to the process wherein the chlorin or chlorin-containing gas is led into a body of boiling oil containing a metal such as finely divided aluminum.

What I claim is l. In the conversion of petroleum oils, the process which comprises heating a body of such oil to a temperature around 500o F. 'in the presence of finely ldivided metal while leading a current of chlorin into contact with such body.

2. In the conversion of petroleum oils, the process which comprises heating a body of such oilto a temperature around 500 F. in the presence of nely divided aluminum while leading a current of chlorin into contact with such body.

3. In the conversion of petroleum oils, the

'process which comprises heating a body of oil to a temperature around 500 F. in the presence of finely divided aluminum while leading a current of chlorin into contact with such body, such body being kept of constant volume during the operation.

4. In the conversion of petroleum oils, the process which comprises heating a ,body of oil to a temperature around 500l5 F. in the presence of finely divided aluminum while leading a current ,of chlorin into contact with such body, vapors of low boiling products being constantly removed during the operation and the volume of'oil being kept constant by additions of fresh oil in corresponding amounts.

5. In thel conversion of petroleum oils, the process which comprises heating a body of oil to a temperature around its boiling point in contact with nely divided aluminum lvgfhdile leading chlorin into contact with such 6. In the conversion of oils, the process which comprises heating a body of oil to a temperature around its boiling point in contact with finely divided aluminum while leading chlorin into contact with such body, the body of oil and metal being kept violently agitated during the operation.

7. The process which comprises leading chlorin into a boiling agitated body of a petroleum oil containing a catalytic metal in suspension, vapors of lower boiling oils produced being constantly removed during -the operation.

8. The process which comprises leading chlorin into a boiling agitated body of a petroleum oil containing a catalytic metal in suspension, vapors of lower boiling oils produced being constantly removed durin the operation and the volume of boiling o1 being kept constant by addition of fresh oil.

9. The process which comprises maintaining a body of oil containing suspended aluminum in vigorous ebullition while introducing chlorin into the same, the volume of oil being kept substantially constant during the operation by introduction of fresh oil to replenish vapor losses and the operation being continued until catalysis with production of low bodies slackens and a granular coky readily settling material forms.

10. The continuous process of converting high boiling petroleum oils to lower boiling oils which comprises maintaining a body of oil containing suspended aluminum in vigorous ebullition while introducing chlorin into the same, the volume of oil being kept substantially constant during the operation by introduction of fresh oil to replenish vapor losses and the operation being continued until catalysis with production of low boiling bodies slackens and a granular coky readily settling material forms, remov` ing such material and adding fresh aluminum. 4

11. In the production of gasolene and burning oils, the process which comprises maintaining a body of petroleum oil containing suspended aluminum in ebullition at a temperature below 600o F. `while introducing a stream of chlorin.

12. ln the production of gasolene and burning oils, the process which comprises `maintaining a body of agitated petroleumA oil containing suspended aluminum in ebullition at a temperature below 6000 F. while introducing a. stream of chlorin, :fresh oil being introduced to maintain the volume of such body constant and vapors of low boiling bodies being continuously removed.

13. ln the production of gasolene and burning oils, the process which comprises maintaining a body of agitated petroleum oil containing suspended aluminum in ebullition at a temperature below 6000 F. while introducing a stream of chlorin, fresh oil being introduced to maintain the volume of such body constant and vapors of low boiling bodies being continuously removed, the temperature of such vapors at the point of exit not being allowed to rise above 350 F.

14C. The process of converting higher boiling petroleum into lower boiling oils which comprises establishing and maintaining a boiling agitated body of such higher boiling oil in the presence of aluminous material assesses and leading a current of a gas containing chlorin into contact with sald body.

15.1The process of converting higherV boiling petroleum into -lower boiling oils which comprises establishing and maintaining a boiling agitated body of such higher boiling oil in the presence of aluminous material and leading a current of a gas containing free chlorin into contact with said body.

16. The process of converting higher boiling petroleum into lower boiling oils which comprises establishing and maintaining `a boiling body of such higher boiling Oil in the presence of aluminous material and leading a current of a gas containing chlorin into contact with said body.

ln testimony whereof7 l aili my signature in the presence of two subscribing witnesses. v

ALMER M. MCAFEE.

Witnesses l. l). McELRoY, Gnonon MCDANIEL.

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