US1221790A - Obtaining products from petroleum by decomposition of component hydrocarbons thereof. - Google Patents

Description

H. P. CHAMBERLAIN. OBTAINING PRODUCTS FROM PETROLEUM BY DECOMPOSITION 0F COMPONENT HYDROCARBONS THEREOF.

APPLICATION FILED OCT. 20. I9I3.

LQQLTQUW Y Patented Apr. 3, IJIT.

Il'gl.

nonacnr. GN M ERLAIN, or BUFFALO, NEwyoRK, ssIsNon' rosraaimmnorn COMPANY or NEW YORK, OF NEW YORK, N. Y., a CORPORATION OFNEW YORK.

oBTAnviNernonucfrs'rnon PETROLEUM 'BY' DEco rosIrmN or COMPONENT HYDBO-' To all whom it may concern:

Be it knownthat I, HORACE 1. CHAMBER- LAIN, a citizen of the United States, residing at Buffalo, in thecounty of Erie and State 5- of New York,have invented certain newand useful Improvements in Obtaining Products from Petroleum by Decomposition .of Com ponent Hydrocarbons Thereof, of which the following is a specification. i

I This invention relates more particularly to obtaining naphtha, burning oil (kerosene), an asphaltic material and another hereinafter mentioned product from petroleum which is of a character to yield paraffin wax; but each of the improvements composing the invention is intended to be secured for all the uses to which it can be applied with or without modification.

Heretoforein my experience petroleum 20 (of the character mentioned) has-most commonly been subjected in the crudeform in which it is producedat the wells, after separation therefrom of water and earthy matter by settling, to distillation under atmospheric pressure at gradually increasing temperatures in one or more stills (with intermediate transfer of the residual oil when more than one .still is used, with cooling or cooling and storage of the so transferred oil when necessary or desired and with condensation of the'va-porsin a series of condensers at different temperatures during part at least ofthe distillation) such distillation has'been 'continueduntil only. a dry coke remains as undistilled residue; and distillates have been obtained principally, if not exclusively, in theseveral forms (a) ofcrude naphtha in one-or more grades, (7)) water white burning oil (kerosene) distillate, (c) mixed distillate -whichconsists in part of hydrocarbons with "boiling points normal for naphtha, in part'of' higher boiling hydrocarbons withviscosities' normal for burning oil (kerosene), and in part of "hydrocarbons-with viscosities too great for normal constituents of burning oil (kerosene) 'and not great enough to'be normal other than light grades of lubricating-mils, (ll) heavy parfaflin distillate-,1 (6) heavy paraffin slop, and" crude still wax, 1 "also =lcnown as wax slop, wax tailings or as gum From the heav mamfi slop and the crude still "wax, an" additional amount of' heavy paraffin dis.- til'latei has becnfobtained by further distiller- 'jcARBoNs THEREOF.

Specification of Letters Patent. te i 3, 11917,

Application filed October 20, 1913. Serial No. 796,310. 7

tion of them. The points atwhich the different cuts (divisions or collections in different receivers) have been made have differed somewhat in different establishments and also at different times in the same establishments, owing to different views of the manufacturers as to the best methods of working, and so on, or to different market conditions. The normal boiling points of burning oil (kerosene) hydrocarbons have been recognized as between 302 F. and 572 F., or 518 F. (Allen, Oommzercz'al- Organic Analysis, vol. 2, London, 1886, pages 397 and 398) as so defined, boiling points normal for naphtha would extend up to 302 F.; but for some years naphtha has included less volatile hydrocarbons; and for the purposes of the present specification volatility normal for naphtha should be taken to include boiling points up to 338 F. For the same purposes viscosities normal for burning oil (kerosene) hydrocarbons may be taken to extend up to seventy seconds at 100 F. by an Engler viscosimeter, on which water would exhibit a. viscosity of fifty three seconds at the same temperature; and the intermediate viscositi es mentioned may be taken as from seventy to one hundred and seventy seconds by the same Engler instrument; which is also re- .ferred to whenever viscosity figures are given hereinafter.

With a view to increasing the yields of naphtha and burning oil (kerosene) hydrov carbons, it was long ago proposed to distil under superatmospheric pressure oils which n are. composed of or contain higher boiling '90 hydrocarbons, as crude petroleum, for example, or undistilled residues of crude petroleum after removal therefrom of crude naphtha and water white burning oil (kerosene) distillate (with or without obtaining more or less of the mixed distillate herein above mentioned). Such proposals seem to have little, if; any, practical value because,

for-onereason, distillation of crude petro leumandits undistilled residuesunder sufficient 'pressure could be carried, on with safety in stills of; practical size only, ,.to a

comparatively slight extent on. account of overheating the still bottoms; lt fore,-,r' e cently it has been proposed to distil .under superatmospheric pressure distillate ;oilscomposedof hydrocarbonswiththe ntermew diate viscosities .mentioned-,-- whichfor; want of more profitable employment have comviscosity at 100 F. What practical use has been-made of these proposals I am not sufficiently informed to state.

I have discovered that the entire heavy parafiin distillate obtained in the distillation of crude petroleum asaforesaid, treated with sulfuric acid and alkali, and retaining its content of paraflin wax, can be distilled under suitable superatmospheric pressure with the production of what may be called high pressure distillate yielding (by appropriate refining) a notable proportion of finished naphtha with boiling points up to 338 F. (more than I have obtained from high pressure distillate produced by distillating said gas oils or fuel oils under like conditions) and also a large proportion of refinedburning oil (kerosene) of better quality than oil distilling over between the same limits of temperature, 338 F. to 518 E, which I have obtained from the high pressure distillate produced by distilling said gas oils or fuel oils under like conditions.

The burning oil (kerosene) from heavy paraflin distillate has been lighter in gravity and lower in viscosity than that from said gas oils or fuel oils and has also proved itself superior to the latter in burning tests, not exhibiting the same tendency as the latter to smoke, to produce a hard crust on the wick or to throw out mushroom-shaped formations of carbon on the wick. This improved quality of burning oil (kerosene) is of special importance on account of the scarcity of high quality oil which could be used to mix with inferior oil in order to increase the yield of a desired standard.

The treatment of the heavy parafiin distillate with sulfuric acid and alkali and the presence therein of paraflin wax aid, each of them, in securing the results stated; but it is believed that advantage over the prior state of the artcan be obtained without the aid of either of said features. Heavy paraflin distillate in each of four forms, that is to say, either pressed or unpressed and either treated oruntreated with sulfuric acid and alkali, can be distilled under pressure in accordance with the invention, althou h not for all of said forms with the same a vanta e.

Such heavy parafiin distillate in each of said forms contains liquid hydrocarbons with viscosities normal to heavy and medium grades of lubricating oils and also hydrocarbons with the intermediate viscosities mentioned in such relative proportions that in the distillation under pressure the decomposition of the hydrocarbons of each of said kinds is modified by the presence of the two other kinds. For exerting such modifying effect the hydrocarbons of any of said kinds should not be less than about ten per cent. by volume of the sum total of the three kinds; and in the distillate mentioned the kind present in least proportion is in excess of such ten per cent. Said distillate is also so far free from still wax and like heavy mat-- (kerosene) the decomposed hydrocarbons may yield also a residual product of an asphaltic character which is useful and I believe new and which is included in the invention as a new article of manufacture or composition of matter.

I have also discovered I believe a new process of distilling hydrocarbon oils under superatmospheric pressure; which I- have applied to heavy parafiin distillate in each of the forms mentioned; but which I believe can be applied advantageously (as compared with the prior state of the art) to other forms of petroleum (including crude oil and undistilled residues in case it should be found expedient to distil the same under superatmospheric pressure, as well as the herein above mentioned gas oils or fuel oils and other distilled or partly distilled products), and also to hydrocarbon oils from other sources than petroleum.

I have also devised a'distilling apparatus which is useful for performing said process and which I believe to be new and consequently rd as forming part of the present inventlon.

The accompanying drawings represent by way of example an apparatus within the invention, Figure 1 being a longitudinal vertical section, partly in elevation, of the still and accessories, without the condenser, Fig. 2 a view in cross section, partly in elevation, showing still and condenser, and Fig. 3 a detail view insection on an enlarged scale mg device in said of an expansion valve appropriate to be em ployed as a vapor thrott apparatus.

The still a is advantageously of box-like form and .of a large enough capacity to be of ractical value in industrial use, say a horlzontally disposed cylinder eight feet in diameter and eighteen to thirty feet in length, or of other appropriate dimensions. It is supported above a fireplace b for heating and has its upper portion exposed to the atmosphere with little or no protection against cooling. It is best provided with a dome 0 also exposed to the atmosphere. The heating means may be of any appropriate description. A burner d is shown by way of example, the same having a gas supply pipe 6 connected therewith and provided with a controlling valve f. Any desired number of burners can be used; also one or more fires burning solid'or liquid fuel can be used in connection with supplementary gas burners; or other heating arrangements can be adopted. The still, when its bottom becomes heated to incipient redness (the ordinary indication of danger to a still bottom from overheating should distillation be continued) ought then to be ableto withstand an internal pressure in such excess of eighty pounds per square inch above atmospheric pressure as to afiord a proper margin of safety.

The intermediate section of the still (see Fig. 2) is best protected both from the atmosphere and from the fire gases, the cubic contents of the so protected portion being not less than about half the capacity of the still. As shown, about a third of the exterior surface of the still is exposed to the atmosphere, approximately another third is exposed to the fire gases, and the remaining portion, approximately one-sixth on each side, is inclosed by and in contact with the walls of the still setting and is so protected thereby both from the atmosphere and from p the fire gases.

The'vapor pipe 9 leads from dome 0 to a condenser of any known or suitable form; shown as a coil 72, immersed in a tank 9'. Water of a temperature to condense naphtha and heavier vapors is supplied to tank j by water inlet pipe in and withdrawn therefrom in a warmer state by water outlet pipe 3. At m within tank j is a gas separating box with a gas escape pipe at leading from its top and a distillate outlet pipe p leading from the bottom to a receiver (not shown). At (1 is a gas main for carrying away the gas to be burned. Additional fuel would, of course, be needed for heating the still a in case gas from the same should be burned under it.

The vapor pipe 9 is provided with an expansion valve r intermediate the dome c of still a and the condenser. As the best conduct of the pressure distillation requires a close regulation of the volume of escaping vapors, the valve port 8 (Fig. 3) is best of small size as compared with the bore of vapor pipe g; which bore should not be less than about three inches in diameter in order to avoid difiiculty from choking. As shown, the valve is closed by a screw t and has a stufiing box it for its stem. Stutling boxes are also shown at w and w for the pipe connections.

The valve shown is a form known on the market as of needle type and employed (for one purpose at least) as an expansion valve in ice machines using liquefied ammonia as the refrigerating agent. A valve of more pronounced needle form (more acute taper and further projection into the port) might have advantages; but the form shown has been found useful. A valve of other than needle type is not necessarily excluded. Heretofore inplans for distilling petroleum and other hydrocarbons oils under superatmospheric pressure it has been proposed to employ a relief valve which-rises automatically when the pressure reaches a certain degree and closes when the pressure falls below the same degree. The use of such auto matic valve is not necessarily excluded; but its use is attended with no advantage, in my opinion; while, on the other hand, it adds complication to the apparatus and is liable to cause danger or inconvenience by sticking. If used, it would be advantageous to provide means for manually regulating the extent of the valves opening and fer forcing it positively to and from its seat, should occasion arise.

The still is shown provided with a pressure gage y for exhibiting the pressure inside the still, a safety valve 2 for relieving said pressure should it accidentally become excessive, a pyrometer 2 for exhibiting the temperature of the oil in distillation, a second pyrometer 3 for exhibiting the tem perature of the vapors in the vapor space at the front of the still, a third pyrometer 4 for exhibiting the temperature of the vapors as they leave the dome 0 and pass over to be condensed as distillate, a valved oil supply pipe 5, a valved discharge pipe 6 for the residual product, a steam pipe 7 for introducing steam at the close of each run in order to expel hydrocarbon vapors and to cool the still ofl' more rapidly, and a manhole 8 for cleaning out the still at the endof each run. Each pyrometer is inclosed in a protecting sheath or pipe 9 closed at the inner end. Electric pyrometers with wires 10 are indicated.

For obtaining the oil to be supplied to still a crude petroleum may well be dis tilled to dryness under atmospheric pressure in one or more externally heated stills (not shown) with gradual rise of temperature and with fractional condensation of the vapors in the latter part at least of the run, customary apparatus being used for the purpose. After the collection of the water white burning oil (kerosene) distillateand of such amount of the mixed distillate coming over subsequently as" may be desired, the distillate which is subsequently received in such distillation may well be collected in the receiver for heavy parafiin distillate as long as it is sufliciently free from still wax to be readily pressed for paraifin Wax. Assuming that the crude oil operated upon is from the Kansas oil fields and has itself a specific gravity of 0.808, such collection may well include all the distillate which at the condenser outlet is between 0.855 and 0904. in specific gravity at 60 F. p v

Distillate which is received afterward in said distillation of the crude oil may well be itself distilled to dryness, and the so obtained distillate, so long as it is free from still wax, be added to the heavy paraffin distillate of the crude oil run.

The thus obtained material would best betillate in the form in which it is considered best to employ the same for decomposition in the still a.

It would consist principally of hydrocarbons, which (if separate) would be liquid at 60 F.; but it would also contain over four per cent. by volume of parafiin wax (in solution). Its liquid portion would comprise hydrocarbons with viscosities normal to medium grades of lubricants (to wit, from one hundred and seventy seconds to two hundred and ninety seven seconds) and also hydrocarbons with viscosities normal to heavy grades of lubricants (to wit, from two hundred and ninety seven seconds upward) as well as hydrocarbons whose viscosities lie between those normal to burning oil (kerosene) and those normal to medium lubricants (to wit, between seventy seconds and one hundred and seventy seconds). Each of these species of liquid hydrocarbons would be present in above 10 per cent. by volume. A sample from a particular lot of treated and unpressed heavy parafiin distillate which had as a whole a specific gravity of 0.881 at 60 F. and whose distillation under pressure gave results hereinafter set forth was chilled and pressed for paraflin wax and yieldedthe latter at the rate of sixteen and a half pounds to each 42- gallon barrel of the unpressed distillate (equivalent to six per cent. by volume). The so pressed sample was then reduced with free superheated steam introduced into the oil and with fractional condensation of vapors in a series of condensers at different temperatures in the manner customary in obtaining lubricating oils (light and medium grades as distillates and heavy grades as residues) from pressed arafiin distillate and in such reduction yiel ed (1) distillate with viscosities at the condenser outlet up to seventy seconds equal to one per cent. by volume of the unpressed distillate, (2) distillate with viscosities at the condenser outlet between seventy seconds and one hundred and seventy seconds equal to fifty six 44/100 per cent. thereof, and (3) distillate with viscosities at the condenser outlet between one hundred and seventy seconds and two hundred and ninety seven seconds equal to thirteen 89/100 per cent. thereof, leaving (4:) residual oil equal to twenty 38/100 per cent. thereof. There was thus an estimated loss of two 29/100 per cent. by volume in the assay.

The treated and unpressed heavy paraflin distillate is introduced through pipe 5 into the still a until the latter is say six-tenths full. The contents of the still are then gradually raised in temperature, with valve 1' open, until the air has been expelledfrom the still and oil appears as condensate at the condenser outlet. Next the valve 1' is closed and the pressure in the still a is allowed to accumulate until the gage 3 shows say pounds per square inch above atmospheric pressure. Thereupon the valve 1" is cautiously opened; and the heating is carefully regulated to maintain said pressure of 75 pounds without greatly exceeding it. The extent to which the valve 1- is opened is an important matter. It may well be opened to such extent that distillate is received from the condenser h at the rate of about two per 7 cent. by volume of the original charge per hour of It may be opened to a lesser extent, as much less as maybe desired; since the only objection to the resultant slower running would be the increased expense due to the longer time to make the run. It may be opened to a greater extent; but with too large an opening excessive firing would be necessary to maintain a proper pressure in the still a; and, in consequence of such firing, the hydrocarbons passing over mightaverage too high in specific gravity for profitable working. A general increase of as much as twenty four one thousandths (0.024) in the specific gravity of the high pressure distillate (as compared with that obtained in a distillation of oil. from the same lot at the said two'per cent. per hour rate) would probably indicate a fatal impairment in the quality of high pressure distillate. Such comparison should be made between samples to be collected at corresponding periods of the runs, to wit, when the distillatereceived in each run shall be the same percentage of the original charge.

The valve 7 can be adjusted during a run, if considered necessary. or expedient, but in normal running the valve opening may be constantly established, so as to allow a continuous escape of the vapors through it and it need not be altered in size, thus allowing an approximately uniform escape of vapors with an approximately uniform pressure in the still.

As distillation proceeds, the oil in distilr Its temperatures will be higher than those of the oil in a parallel run under atmospheric pressure; but they may be (and in distilling heavy paraffin distillates under a pressure of seventy five pounds have been found to be) below those at which the vapor tension of the undecomposed oil is estimated to equal the still pressure on the basis of considering the'rise in vapor tension of the undecomposed oil for a given number of degrees F. above its boiling point to be equal (or sufficiently near equal) to the rise in vappr tension of benzene (coal tar naphtha, C for an equal number of degrees F. above its boiling point and the temperatures of the oil in distillation in a parallel run under atmospheric pressures to represent (with sufficient accuracy) the boiling points of the undecomposed oil. Hereinafter atable is given which shows the temperatures of the oil in parallel runs on heavy parafiin distillate under atmospheric pressure and ,under seventy five pounds superatmospherlc respectively; and it'will be observed by reference thereto that at corresponding periods of the runs the difference is less than 131 F.; which is the difference in temperature betweenbenzene at its boiling point (where its vapor tension equals the pressure of the atmosphere) and at the point where its vapor tension is seventy five pounds to' the square inch" above atmospheric pressure.

i The evolved vapors are cooled in the exposed upper part of still a and in dome 0 to acon-siderable extent (say between about 150 F. and about 350 F. below the contemporaneous temperatures of the oil in distillation) before they pass over to be condensed as distillate. Such cooling results ina partial condensation of said vapors and the formation of condensatewhich returns to the oil in distillation. It is conceived that some hydrocarbon components of the oil in still a will vaporize without decomposition, owing to the presence in the still a of the vapors of lighter (more Volatile)- hydrocarbons formed bv decomposition, notwithstanding the fact 'that the temperature of the oil in distillation is below the estimated boiling point of the latter underthe pressure in the still a. v v I The followimr table gives figures which were obtained in runs performed at the rates indicated in the table with a small still (a' horizontal cylinder ZOinches in diameter by 42 inches long with a dome four inches in diameter and six inches high) on batches from the same lot ofoil. one under atmospheric pressure and'the other under a super atmospheric pressure as near 75 pounds" to the square inch as practicable without falling below the same. The total hours and minutes of performing the respective runs, in connection with the total percentages received therein, show averageyields of distillate equal to about seven and a half per cent. by volume ofthe original charge per hour in one runand about eight oer cent. per hour in the other; but in industrial, operations a lesser rate is considered better as herein above indicated.

The specific gravities in the table are those of the several fractions of distillate of 5% each by weight: and the times in minutes are those in which said fractions were severally received.

Atmospheric pressure. 75 pounds gage pressure;

Fractions 52 g; E}, I i g, 5Z5, 2 125. E'

7 I? s a 1% s Q w E1 I 13 w E-* 1 663 588 8236 40 766 512 .7569 48 2 e79 582 Y 8473 v 43 75 520 '.7e7s 43 3 691 624 .85 29 45 '66 525 7esa 4e 4. 701 6 35 ss se befs 76a] T550 ".7762 as 5 71o. sa5 .8581) 40 775 529' ..-777o l s 715 s 540 I "77 530 .7758 41 9 no 680 .8555 44 793 545 46 1o 741 635 .8 13 43 804 550- .7945 37 11 752 655 .8519 40 811 554 .7967 as 12 760 688 .8514 as. sis 546. 3e

Totaldistillate time9h.39m.; totaldis.-70%; t'ime9 h.36 m.

Percentages in tableby weight, not volume; total distillate 72% by volume in run under atmospheric pressure, and 78.2% by volume in run under 75 pomids'gage pressure. 7

In giving these and other figures in detall, 1t Wlll be understood that they are by way of example only, in order the better to enablethose skilled in the art to pracwre: the invention.

It is considered best in distilling under pressure that the evolved vapors should not be heated above the contemporaneous temperatures of the oil in distillation. As shown, therefore, only the bottom third or thereabout of the exterior surface of the still is exposed to the fire gases; so that the walls of the vapor space, even when this space is enlarged by progress of the distillation, will not be exposed thereto. The cooling of the vapors is efi'ected as shown by the exposure of the still top and dome to the cooling influence of the atmosphere. The work performed by the vapors in expanding as they pass the valve 1' in distillation under high pressure, with said valve within a short distance from dome 0, also exerts a cooling effect on the vapors in said dome c. condensate as formed drops (or else runs down the sides of the still) into the oil in distillation. A partial condenser exteriorly located and connected with the still by a vapor pipe and a run back for returnmg condensate could be used instead of or in addition to cooling in the vapor space (including dome space when a dome is used).

By having the middle section of the still inclosed by and in contact with the walls of the still setting, the vapors are protected not only against overheating, as just mentioned, but also against the undue cooling which might result from enlargement of the vapor space during the run, were said middle section exposed to the atmosphere. The distillation would best be continued as long as it is safe to do so, in view of the superatmospheric pressure in the still. The limitof safety would probably be about reached when the appearance of the still. bottom indicates incipient redness.

The run being thereupon terminated, the asphaltie material in the still a is withdrawn through pipe 6 and a cooler (not shown) into an appropriate receiver (not shown); the still is subsequently cooled (after introduction of free steam through pipe 7 to expel the vapors, the manhole 8 being opened as the steam first enters) the still is cleaned; and it is then ready to receive a new charge of the treated impressed heavy paratlin distillate.

The high pressure distillate from condenser coil It may well be collected in a single receiver (none shown) and he then fractionated into naphtha, burning oil (kerosene) and a heavier oil. useful as gas or fuel oil. Said heavier oil, also any residue obtained in rerunning the burning oil (kerosene) portion of the high pressure distillate, could be added in whole or in part to a new charge. of the heavy parallin distillate, if so meter-red. ()ther oils could also be added, if so desired, such as residues (hottoms) from rerunning the water white distillate and the mixed distillate of the crude The oil run. Instead of a single condenser h as shown, a series of condensers maintained at difi'erent temperatures could be applied tthe pressure still a.

The asphaltic residual material withdrawn from the still a at the close of the high pressure run in which the figures of the table were obtained had as a whole a specific gravity of 1.0772, and was as a whole ninety eight 65/100 per cent. soluble in carbon bisullid and eighty two 95/100 per cent. soluble in naphtha obtained from Kansas crude oil and consisting of hydrocarbons with specific 'gi'avities ranging from 0.7520 to 0.7002.

If so desired, the pressure distillation can be arrested before the material in the still attains the specific gravity mentioned. Also, if so desired, further distillation can be carried on under atmospheric or other reduced pressure, with or without introduction of free superheated steam or other aeriform fluid (including atmospheric air, should it be desired to modify the composition by oxidation). As obtained from the high pressure still the asphaltic material will ordinarily be soft and sticky even at zero F., on account of the conduct of the distillation only while it can be carried on with safety; but by reduction (partial evaporation) under atmospheric pressure at appropriately high temperature and with introduction of superheated steam into the melted material, it can be brought to such condition that when cool a lump of the same can be molded and drawn out into threads. Distillate obtained from such reduction can be added to heavy paraffin distillate to be distilled under the high pressure mentioned; it could be used as gas oil or fuel oil; or it could be otherwise disposed of, as preferred.

The solution of the asphaltie material as obtained from the high pressure still in the naphtha mentioned (in such proportions as to give the desired fluidity for application) constitutes an excellent varnish or protective coating. The material can be so dissolved and used after reduction (partial evaporation) and oxidation (either or both). It can be used also (alone or in connection with asphaltum and with or without reductionand oxidation, either or both, as may be necessary or expedient) for paving and roofing purposes and for other purposes to which asphaltum has been applied.

While it is considered best to charge the pressure still with an oil which represents an entire range of hydrocarlmns from and including some with the intermediate viscosities mentioned to and including those. recovered from heavy parallin slop, more or less of said hydrocarbons can be collected separately, if so preferred, and only the res inainder of them charged into the still.

menace It is also permissible. within the limits of 5 and those with viscosities normal to lubrieating oils of (either or both) medium and heavy grades, the Words artificial mixtures being used in opposition to a natural mixture of said kinds of hydrocarbons such as exist, for example, in heavy paraffin distillate obtained as aforesaid.

Also oil composed of or containing hydrocarbons with the intermediate viscosities mentioned can be enriched with parafiin wax or an appropriate substitute artificially, or by collectmg a distillate containing paraffin wax.

Yet further within the limits of the invention oil containing liquid hydrocarbons with viscosities normal to medium and heavy lubricating oils oil containing hydroc'ar ons with the intermediate viseosities mentioned can be. distilled separately under pressure and the resulting products can then be mixed. In this way burning oil (kerosene) from distilling oil of the latter kind under pressure can be improvedby the better quality of that from distilling oil of the former kind. I have obtained larger yields, however, both of naphtha and of burning oil (kerosene) from distilling mixtures of (1) hydrocarbons with viscosities normal to heavy lubricating oils and (2) hydrocarbons with the intermediate viscosities mentioned than from distilling like volumes of said two kinds of liquid hydrocarbons separately; and I believe that the same principle would hold true in respect to mixtures containing hydrocarbons with viscosities normal to medium lubricating oils. It is also my belief that better results are attainable by distilling oil in which two or more of said three kinds of liquid hydrocarbons are naturally present than by separating such hydrocarbons and then forming a mixture artificially of them in their original proportions.

Inmaking heavy parafiin distillate a certain amount of decomposition is considered necessary in order to form crystallizable paraffin wax. It is provoked by introducing little or no inert aeriform fluid (like superheated steam) into the still and by cooling the evolved vapors sufiieiently to form a condensate which is returned to the oil in distillation. 'Ihe cracking customary in making heavy paraffin distillate is considered advantageous where such distillate is to be subjected to pressure distillation, for one reason because it removes from the distillate certain coke forming elements; and, if preferred, it can be carried further in preparing distillate for subsequent pressure distillation than is customary in preparing heavy parafin distillate. On the pherie pressure.

(either or both) and.

other hand, it need not necessarily be carried to this extent or to any avoidable ex-.

tent within the limits of the invention as expressed in some at least of the claims.

Aeriform fluid, such as superheated steam, could, for example, be introduced intov crude petroleum in preparing a distillate to be itself distilled under superatmospheric pressure.

In the pressure distillation it is considered best, as mentioned herein above, to use about 75 pounds to the square inch above atmos- Above this pressure the yields of naphtha and hiring oil have not been found by me to increase (rather the reverse); while, of course, the danger increases with the pressure. Below 75 ounds pressure I have found the yields to all off gradually with the ution of pressure; so that under 30 pounds 'the yield of naphtha has been about three-fifths and under 20 pounds less than half of the yield under 7 5 pounds; while the yield of burning oil (kerosene) under 30 pounds has been about four-fifths and under 20 pounds less 'than three-fourths of the yield under 75 pounds. In order that, in a run under 30 pounds, the temperatures of the oil in dis-,

tillation may not be as high as those at which the vapor tension of the undecomposed oil is estimated to equal the still pressure, said temperatures should not be so much as about 73 F. above the temperatures attained at corresponding periods in a parallel run under-atmospheric pressure. In runs under a pressure other than 30 pounds and 7 5 pounds, the temperatures of the oil in distillation should be within a corresponding mam'mum above the so attained temperatures in order that they may be less than those at which the vapor tension of-the undecomposed oil is estimated to equal the still pressure. The vapor tensions of benzene (G l-I are known for a wide range of temperatures. Such tension amounts to 30 pounds super-atmospheric at about 73 F. above the boiling point, to wit, at about 250 F., the'boiling point of benzene being about 1| F.

The application of the invention, or of applicable portions thereof, to petroleum not of a character to yield paraflin wax and to hydrocarbon oils other than petroleum will be sufiiciently evident from the preceding description. There may well be petroleum which does not yield paraffin wax, but which does yield distillate composed of liquid hydrocarbons divisible by their respective viscosities into the three kinds mentioned; and there may well be petroleum which does not yield distillate having hydrocarbons 'so divisible; but all crude petroleum can be distilled to dryness under a suitably low pressure and with or without designedly provoked cracking in order to obtain distillate to be decomlp pressure, w ich distillate may; contain at least the higher boiling hydrocarbons ylelded by such petroleum down to but excluding last runnings that would be objectionable by reason of the presence therein of still wax or like heavy matters of sticky. character,;.. but not necessarily excluding desirable hy dlrocarbons recoverable by the rerunning of s ops.

Instead of relieving the vapors (to wit, at valve'r) from the high. pressure under which they are evolved in still a prior to their condensation (to wit, in condenser 71.), they can be held under said pressure (to wit, by appropriate provisions, not shown, such as qvalves, forexample, in pipes n and 12) until condensed as distillate without there-Q by necessarily discarding all the new,"use-" ful and original features of the present invention. Either way the contents of the still would be confined in order to develop therein the superatmospheric pressure mentioned. I

Working on the continuous system (in which a more or less continuous stream of oil is supplied to a highpressure still and a like stream of residuum withdrawn therefrom during the progress of the distillation) is not necessarily excluded from the scope of the present invention; although it is considered more advantageous to work by the batch system, as herein above described (in which a'charge of oil is supplied to still a and-then runoif to the desired extent, the still being thereupon emptied preparatory to receiving a new char e).

, The mention of particular modifications is not intended to exclude others not menosed by; distillation underhigh tioned in which the substance of one or more of the hereinafter written claims may be embodied.

In reciting in claims following that the oil is free from still wax and like heavy matters of sticky character and from elements yielding the same or coke, a practical rather than a theoretically erfect freedom is to be understood. It ces, for example, for the oiloperated upon to be distillable in an externally heated still of the dimensions hereinbefore mentioned for still a (charged six-tenths full) under a superatmospheric pressure of seventy five pounds to the square inch at the aforesaid rate of two per cent. per hour to the extent of fifty per cent. or more by volume of its component hydrocarbons which have viscosities above seventy seconds at 100 F. withou heating the still bottom to redness.

I claim as my invention or discovery:

1. The process of obtaining hydrocarbon products by decomposition of hydrocarbons, whichprocess consists in operating upon an oil that contains hydrocarbons wlth viscosities intermediate seventy seconds and one hundred and seventy seconds 813100 F. and

carbons of either-kind to not exceeding ninety per cent. of hydrocarbons of the other kind and that is free from still wax :v andlike heavy matters ofsticky character and from elements yielding the same or coke by distilling such oil at decomposing temperatures under a superatmospheric pressure of not less-than thirty pounds per square inch, substantially as described.

2. The process of obtaining hydrocarbon products by decomposition of hydrocarbons, which process consists in operating upon an oil that. contains parafiin wax and also liquid hydrocarbons with viscosities too great for normal. constituents of burning oil (kerosene) 1n the relative proportions of not less than four nor more than ninety percent. of paraflin wax to not more than ninety six per cent. nor less than ten per cent. of said liquid hydrocarbons and that is free from still wax and like heavy matters of sticky character and from elements yielding the same or coke by distilling such oil at decomposing temperatures under a superatmospheric pressure of not less thanthirty pounds per square inch, substantially as described.

3. The process of obtaining hydrocarbon products by decomposition of hydrocarbons,

which process consists in subjecting to distillation at decomposing temperatures under a superat'mospheric pressure of not less than thirty pounds per square inch the heavy paraflin distillate which is -.collectable in an appropriate distillation of crude petroleum of a character to yield paraflin wax, which is free from still wax and like heavy matters of sticky character and from elements yielding the same or coke,\and which consists of hydrocarbons with viscosities ranging from below one hundred and seventy seconds at 100 F. to above two hundred and ninety seven seconds at 100 F., upward of ten per cent. by volume of said hydrocarbons having viscosities intermediate seventy seconds and one hundred and seventy seconds at 100 F substantially as described.

4. The process of obtaining hydrocarbon products by decomposition of hydrocarbons, which process consists in distilling crude petroleum approximately to the point at which the distillate would no longer be free from still wax or like heavy matters of sticky character, collecting distillate up to this point from a point so early in the run that hydrocarbons with viscosities intermediate seventy seconds and one hundred and seventy seconds at 100 F. represent upward of ten per cent. by volume of the so collected distillate, and subjecting the so collected distillate to distillation at decomposing temperatures under a superatmospheric pressure till of not less than thirty pounds per square inch, substantially as described.

5.-The process of obtaining hydrocarbon products by decomposition of hydrocarbons, which process consists in distilling crude petroleum approximately at least to dryness, collecting distillate in such complete distillation in distinct portions, one of them containing the runnings to approximately the point at which the so collected distillate would be no longer free from still wax and like heavy matters of sticky character from a point so early in the run that hydrocarbons .wlth viscosities intermediate seventy seconds and one hundred and seventy seconds at 100 F. represent upward of ten per cent. by volume of the so collected distillate, and the other of them comprising the subsequent runnings, distilling these subsequent runnings approximately at least to dryness with .collection by itself =of distillate free from still wax and like heavy matters of sticky character, mixing this latter distillate with said first portion of distillate from the crude oil run, andsubjecting the mixed distillates to distillation at decomposing temperatures under a superatmospheric pressure of not less than thirty pounds per square inch, substantially as described.

6. The process of obtaining hydrocarbon products by decomposition of hydrocarbons,

which process consists in obtaining oil that consists of a-natural mixture of hydrocarbonsvwith viscosities intermediate seventy seconds'and one hundred and seventy seconds at 100 F. and hydrocarbons with higher viscosities including those above two hundred and ninety seven seconds at 100 F.

in the relative proportions of not less than ten per cent. by volume of hydrocarbons of either kind to not exceeding ninety per cent. of hydrocarbons of the other kind and that is free from still wax and like heavy matters of sticky character and from elements yielding the same or coke, and distilling such oil at decomposing ten ratures under a superatmospheric pressure of not less than thirty pounds per square inch, substantially as described.

7. The process of obtaining hydrocarbon products by decomposition of hydrocarbons,

which process consists in distilling at defree from said matters and elements, and uniting hydrocarbons given ed as vapors in such distillation from said two ,kinds of parent hydrocarbons in the relative proportions of not less than ten per cent. by volume of product from either kind to not exceeding ninety per cent. of product from the other kind, substantially as described.

8. The process of obtaining hydrocarbon products by decompositionof hydrocarbons, which process consists in distilling at decomposing temperatures under a superatmospheric pressure of not less than thirty pounds to the square inch, parafiin wax in a form that is free from still wax and like heavy matters of a sticky character and from elements yielding the same or coke and in also distilling at decomposing temperatures under said superatmospheric pressure liquid hydrocarbons that have viscosities too great for burning oil (kerosene) and that are free from still wax and like heavy matters of a sticky character and from elements yielding the same or coke, and uniting hydrocarbons given off as vapors in such distillation from said paraffin wax and said liquid hydrocarbons in the relative proportions of not less than four nor more than ninety per cent. by volume of product from "said paraflin wax to not more than ninety six per cent. nor less than ten per cent. of product from said liquid hydrocarbons, substantially as described.

9. An asphaltic material for varnish making and other uses, the same being as a whole more than ninety percent. by volume soluble in bisulfid of carbon and more than seventy five per cent. soluble in petroleum naphtha, and consisting over fifty per cent. of hydrocarbons that are heavier than water and are of a coherent and ductile character and that are residues of the decomposition of hydrocarbons with viscosities intermediate seventy seconds and one hundred and seventy seconds at 100 F. and also of liquid hydrocarbons with higher viscosities in the relative proportions of not less than ten per cent. by volume of product from hydrocarbons of either kind to not exceeding ninety per cent. of product from hydrocarbons of the other kind, substantially as described. Y

10. An asphaltic material for varnish making and other uses, the same being as a whole more than ninety per cent. by volume soluble in bisulfid of carbon and more than seventy five per cent. soluble 'in petronot less "than four nor more than ninety per cent-ofproduct from paraflin wax to not more than ninety six'nor'less than ten per cent. of product from said hquld' hydro- .jcarbons, substantially as desdribed.

11. The process of distilling petroleum or other hydrocarbon. oil under superatmosphericlpr'essure for obtalning products by decomposition, which process'consists in (1) within twenty'four one thousandths of those obtained in corresponding periods in a test run in which such passing vapors have formed condensate at the rate of two per cent. by volume of an original charge per hour, and (3) controlling said heating and confining the liquid contents of the still in such manner as to maintain the oil in distillation at. a decomposing temperature and under a pressure of evolved vapors which 1s above a minimum within the pressure mentioned, substantially as described.

12. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products b decomposition, which process consists in (1) heating said petroleum or other oil in an appropriate form to temperatures suflicient to effect decomposition of the oilunder a superatmospherlc pressure of not less than thirty pounds per square inch, when the still contents are suitably confined, (2) conducting the evolved vapors to condensing means through an opening that is constantly established in normal running and is not alterable automatically by variations of pressure either to be automatically closed and reestablished by such variations or to be otherwise varied automatically thereby and is of appropriate size to keep the specific gravities of distillate leaving said condensing means within twenty our one thousandths of those obtained in corresponding periods in a test run in which such passing vapors have formed condensate at the rate of two per cent. by volume of an original charge per hour, and (3) controlling said heating and confining the liquid contents of the still in such manner as to maintain the oil 'in distillation at a decomposing temperature and under a pressure of evolved vapors which is above a minimum within the pressure mentioned, substantially as described.

13. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in (1) heating said petroleum or other oil in an appropriate form to temperatures sufiicient to effect decomposition of the oil under a superatmospheric pressure of not less than thirty pounds per square inch, when. the still contents are suitably confined, (2) conducting the evolved vapors to condensing means through an opening that is constantly established in normal running and can be closed and reestablished and also varied in size manually by an attendant and that is of appropriate size to keep the specific gravities of distillate leaving said condensing means within twenty four one thousandths of those obtained in corresponding periods in a test run in which such passing vapors have formed condensate at the rate of two per cent. by volume of an original charge per hour, and (3) controlling said heating and confining the liquid contents of the still in such manner as to maintain the oil in distillation at a decomposing temperature and under a pressure of evolved vapors which is above a minimum within the pressure mentioned, substantially as described.

14. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in (1) heating said petroleum or other oil in an a propriate form under a superatmos heric pressure of not less than thirty poun s per square inch, sufficiently to induce decomposition of component hydrocarbons, (2) effecting said decomposition at gradually increasing temperatures that are below the respective points at which the ordinary vapor tension of the undecomposed oil is estimated to equal the still pressure, to wit, when the still pressure is thirty pounds superatmospheric efl'ecting said decomposition at temperatures not so much as seventy three degrees F. above those attained in a parallel distillation under atmospheric pressure, when the still pressure is seventy five pounds superatmospheric efi'ecting said decomposition at temperatures not so much as one hundred and thirty one degrees F. above the so attained temperatures, and when another still pressure is employed effecting said decomposition at temperatures within a corresponding maximum above the so attained temperatures, (3) cooling the evolved vapors to between one hundred and fifty and three hundred and fifty degrees F. below the contemporaneous temperatures of the oil in distillation, (4) returning the so formed condensate to the oil in distillation, and (5) condensing the residue of said vapors as distillate, substantially as described.

15. The process of distilling petroleum mamoo or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in (1) heating said petroleum or other oil in an appropriate form under a superatmospherlc pressure of not less than thirty pounds per square inch, sufliciently to induce decomposition of component hydrocarbons, (2) efiecting said decomposition at gradually increasing temperatures that are below the respective points at which the ordinary vapor tension of the undecomposed oil is estimated to equal the still pressure, to wit, when the still pressure is thirty pounds superatmospheric effecting said decomposition at temperatures not so much as seventy three degrees F. above those attained in a parallel distillation under atmospheric pressure, when the still pressure is seventy five pounds superatmospheric effecting said decomposition at temperatures not so much as one hundred and thirty one degrees F. above the so attained temperatures, and when another still pressure is employed effecting said decomposition at temperatures within a corresponding maximum above the so attained temperatures, (8) cooling the evolved vapors to below 550 F. and not so low as to prevent the passage over of hydrocarbons with boiling points intermediate 338 F. to 518 F., (4) returning the so formed condensate to the oil in distillation, and (5) condensing the residue of said vapors as distillate, substantially as described.

16. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in ('1) heating said petroleum or other oil in an appropriate form under a superatmospherie pressure of not less than thirty poundsand not so much as one hundred pounds per square inch sufficiently to induce decomposition of component hydrocarbons, (2) effecting said decomposition at gradually increasing temperatures that are below the respective points at which the ordinary vapor tension of the undecomposed oil is estimated to equal the still pressure, to wit, when the still pressure is thirty pounds superatmospheric efiecting said decomposition at temperatures not so much as seventy three degrees F. above those attained in a parallel distillation under atmospheric pressure, when the still pressure is seventy five pounds superatmospheric effecting said decomposition at temperatures not so much as one hundred and thirty one degrees F. above the so attained temperatures, and when another still pressure is employed efl'ecting said decomposition at temperatures within a corresponding maximum abovethe so attained temperatures, (3) cooling the so evolved vapors to between one hundred and fifty and three hundred and fifty degrees F. below the contemporaneous temperatures of the oil in distillation, (4) returning so formed condensate to the oil in distillation, and (5) condensing the residue of said vapors as distillate, substantially as described.

-17. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products b decomposition, which process consists in (1) heating said petroleum or other oil in an appropriate form under a superatmos heric pressure of not less than thirt poun s and not so much as one hundre pounds per square inch, sufliciently to induce decomposition of component hydrocarbons, (2) effecting said decomposition at gradually increasing temperatures that are below therespective points at which the ordinary vapor tension of the undecomposed oil is estimated to equal the still pressure, to wit, when the still ressure is thirty pounds superatmospheric eifecting said decomposition at temperatures not so much as seventy three degrees F. above those attained in a parallel distillation under atmospheric pressure, when the still pressure is seventy five pounds superatmospheric efl'ecting said decomposition at temperatures not so much as one hundred and thirty one degrees F. above the so attained temperatures, and when another still pressure is employed effecting said decomposition at temperatures Within a corresponding maximum above the so attained temperatures, (3) cooling the so evolved vapors to below 550 F. and not so low as to prevent the passage over of hydrocarbons with boiling points intermediate 338 F. and 518 F., (4) returning so formed condensate to the oil in distillation, and (5) condensing the residue of said vapors as distillate, substantially as described.

1 18. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products-by decomposition, which process consists in (1) heating to decomposing temperatures a batch of said petroleum or other oil in an appropriate form under a superatmospheric pres sure of not less than thirty pounds per square inch, (2) so cooling the evolved vapors in the space above the oil in distillation by exposure of the still top to the atmosphere as to effect a partial condensation of the vapors in said space, (3) protecting said vapors against excessive cooling due to enlargement of said space by diminution ,in volume of the oil in distillation as well as against superheating above the contemporaneous temperatures of said oil, (4) returning condensate formed by said cooling to the oil in distillation, and (5) conducting residual vapors away for condensation as distillate, substantially as described.

19. The process of distilling petroleum or other hydrocarbon oil under superatmos- 'pheric' pressure for obtaining productsby decomposition, which process consists in (1 heating to decomposing temperatures a batch of said petroleum -or other oilin an appropriate form under a superatmos heric pressure of not less than thirty poun siper square inch, (2) so cooling the evolved vapors in the space above the oil in distillation by exposure of the still top to the atmosphere as to effect a partial condensation of the vapors in said space, (3) protecting said vapors against excessive coolmg due to enlargement of said space by diminution in volume of the oil in distillation as well as against superheating above the contemporaneous temperatures of said oil, (4) returning condensate formed by said cooling to the oil in distillation, and (5) conducting residual vapors away through a throttling device for condensation under reduced pressure as distillate, substantially as described. 20. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in (1) heating said petroleum or other oil in an appropriate form under a superatmospheric pressure of not less than thirty pounds per' squareinch sufliciently to induce decom os1- tion of component hydrocarbons, (2) e ecting said decomposition at gradually increasing temperatures under an at least approximately uniform pressure, (3) preserving the evolved vapors from heating above thecontemporaneous temperatures of the oil in distillation, (4) allowing the vapors to escape continuously through a throttling device at a sufficiently small rate to produce distillate whose s ecific gravity will not be more than twenty our one-thousandths (0.024), if any, greater than that of the distillate which would be obtained in a parallel distillation performed at a two per cent. per hour rate, and (5) condensing the so escaping vapors as distillate, substantially as described.

21. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in (1) heating said petroleum or other oil in an appropriate form under a superatmospheric pressure of not less than thirty pounds per square inch sufficiently to induce decomposition of component hydrocarbons, (2) effecting-said decomposition at gradually increasing temperatures under an at least approximately uniform pressure, (3) cooling the evolved vapors under superatmospheric pressure to below 550 F. and not so low as to prevent the passage over of hydrocarbons with. boilin points intermediate 338 F. to 518 F., (4 returning the so formed condensate to the oil in distillation, (5) allowing the uncondensed vapors to escape continuously throu h a throttlin device at a sufficiently smal rate to pro uce distillate whose specific gravity will not be more than twenty four one-thousandths (0.024), if any, greater than that of the distillate which would be obtained in a parallel distillation performed at a two per cent. per hour rate, and (6) condensing the so escaping vapors as distillate, substantially as described.

22. The process of distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which process consists in (1) heating said petroleum or other oil in an a propriate form under a superatmos heric pressure of not less than thirty poun s per square inch sufiicientlyto induce decomposition of component hydrocarbons, (2) effecting said decomposition at gradually increasing temperatures under an at least approximately uniform pressure, (3) preserving the evolved vapors from heating above the comtemporaneous tem eratures of the oil in distillation, (4) coo ing the evolved vapors under superatmospheric pressure to below 550 F. and not so low as to prevent the passage over of hydrocarbons with boilin points intermediate 338 F. to 518 F., (5 returning the so formed condensate to the oil in distillation, (6) allowing the uncondensed vapors to escape continuously through a throttling device at a sufficiently small rate to produce distillate whose specific gravity will not be more than twenty four one-thousandths (0.024), if any, greater than that of the distillate which would be obtained in a parallel distillation performed at a two per cent. per hour rate, and (7 condensing the so escaping vapors as distillate, substantially as described.

23. Apparatus for distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which a paratus comprises (1) a horizontal cylin er still having its upper part exposed to the atmosphere for cooling and its lower part to fire gases for heating, and an intermediate portion, equal in cubic contents to not less than half the capacity of the still, that is protected both from the atmosphere and from the fire gases, said still being of practical size, strong enough to resist an internal superatmospheric pressure of more than thirty pounds to the square inch, adapted for batch running in which the volume of oil in the still diminishes during the run, and so constructed interiorly that condensate formed in the vapor space is returned to the oil in distillation, (2) an outside condenser provided with a distillate draw oil", (3) a vapor pipe leading from said still to said outside condenser, and (4) means for maintaining a superatmospheric pressure in excess of thirty pounds per square inch in said still during distillation, substantially as described.

24. Apparatus for distilling petroleum or other hydrocarbon oil under superatmospheric pressure for obtaining products by decomposition, which apparatus comprises (1) a horizontal cylinder still having its upper part exposed to the atmosphere for cooling and its lower part to fire gases for heating, and an intermediate portion, equal in cubic contents to not less than half the capacity of the still, that is protected both from the atmosphere and from the fire gases, said still being of practical size, strong enough to resist an internal superatmospheric pressure of more than thirty pounds to the square inch, adapted for batch running in which the volume of oil in the still diminishes during the run, and so construct-- ed interiorly that condensate formed in the vapor space is returned to the oil in distillation, (2) an outside condenser provided with a distillate draw oil, (3) a vapor pipe leading from said still to said outside condenser, and (4) a vapor throttling device located intermediate said still and said outside condenser and adapted to hold the vapors in 7 said still under superatmospheric pressure in excess of thirty pounds per square inch,

'while allowing said vapors to escape through said throttling device to said outside condenser, substantially as described.

25. The process of obtaining hydrocarbon products by decomposition of hydrocarbons, which process consists in distilling crude petroleum to beyond the point at which the stream at the condenser outlet exhibits a viscosity of one hundred and seventy seconds at 100 F., collecting in this distillation a cut of distillate, free from still wax and like heavy matters of sticky character, which cut begins so far below and ends so far above the point just mentioned that neither the hydrocarbons therein with viscosit-ies intermediate seventyseconds and one hundred and seventy seconds at 100 F. nor the more viscous hydrocarbons constitute less than 10 per cent. by volume of all the component hydrocarbons thereof with viscosities above seventy seconds at 100 F., and subjecting so obtained and so constituted distillate to distillation at decomposing temperatures, under a superatmospheric pressure of not less than thirty pounds per square inch, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

HORACE P. CHAMBERLAIN.

Witnesses:

G. W. ARMSTRONG, E. A. CO'ITEN.

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