US1392584A - Art of distilling petroleum-oils - Google Patents

Description

F. B. LEWIS AND T. S. COOKE.

ART OF msmuwe PETROLEUM OILS.

APPLICATION FILED MAY 7, 191?.

Patented Oct. 4, 1921.

a mm L 5 i a UNITED STATES FRANK B. LEWIS AND THOMAS S. STANDARD OIL COMPANY, OF DIANA.

PATENT OFFICE.

AB'I OF DISTILLING PETROLEUM-OILS.

Specification of Letters Patent.

Patented Oct. 4, 1921.

Application filed Kay 7, 1917. Serial No. 166,965,

To all whomitmay concern:

Be it known that we, FRANK B. LEVIS and THOMAS S. Coons, citizens of the United States, residing at \Vhiting, in the county of Lake and State of Indiana, have invented a new and useful Improvement in the Art of Distilling Petroleum-Oils, of which the following is a specification.

Our invention relates to the art of distilling petroleum oils and more particularly to a process, of distillation conducted under pressure'for the purpose of effecting the conversion of heavier or high boiling point oils into lighter or lower boiling point oils, as is more fully described in the patent to m. M. Burton, No. 1,049,667.

We have discovered that a distillation process of this character may be accelerated and made to yield superior results both quantitatively and qualitatively if the vapors passing from the still are subjected to the absorbing or direct condensing action of a body or bodies of liquid, as for exam 1c in a fractionating column or the like. l 3y the use of such a fractionating means there are condensed from the outgoing vapor stream practically all constituents thereof which have not suffered sufficient decomposition, and at the same time the condensing effect is so perfectly controlled that no substantial proportion of the vapors which have suffered sufficient decomposition is condensed. In practice we prefer to connect the inlet end of the fractionating column or its equivalent directly with the still, so that the refluxing condensate may return immediately and continuously to the still. "e also pre or toconnect the vapor outlet at the top of the fract-ionating column or its equivalent, through .an open pipe, directly with a water cooled condenser in which the vapors constituting the net result of the process are condensed under the same pressure obtaining in the still and its connecting fractionatin column.

Tlie invention will be fully understood from the following detailed description of one method of carrying out the same. In this description, reference will be had to the accompanying drawing which illustrates more or less diagrammatically an arrangement of still, fractionating column and final condenser, which we find well suited to the practice of our invention.

In this drawing the numeral 1 designates atinc column illustrated in the drawing is of the outline of a vertical cylinder having arranged in its interior a plurality of pans 6, each of which is provided with vapor ducts 7 capped by heads 8 which are perforated at their side walls near the bottom of the pan. A constant level of liquid is maintained in each pan by means of an overflow pipe 9 which discharges into the next lower pan. The bottom pan designated 6 is spaced some little distance above the lower end of the column, and the overflow pipe 9 for this pan carries an inverted siphon or trap 10. The reflux condensate collecting in the bottom of the column is returned to the still by a drain pipe 11 tapped into the back head of the still and connect ing within the still with an inverted siphon 12 (shown in dotted line) by which the reflux condensate is carried down near the hot bottom of the still and again brought upwardly and discharged into the upper portion of the still at a point above the average liquid level and not substantially below the highest liquid level therein.

From the upper end of the fractionating column the outgoing vapors are carried through a line 13 to a condensin coil 14 mounted in a water bath 15. This coil drains into a receiving drum 16 provided at the bottom with a li uid drawofl pipe 17 and at the top with a va ved gas-escape and control pipe 18.

I The operation of this apparatus is as folows:

A charge of relatively heavy or high boiling hydrocarbon oils from which it is desired to produce a maximum quantity of relatively low boiling point or li ht hydrocarbons, is introduced into the stifi 1 and by means of the furnace 2 the contents of the still are raised to the temperature at which distillation begins. It may be noted that in order to prevent the distillation of an part i of the charge contained within the stil 1 before the desired operating temperature has been reached. it is of advantage to introduce into the still and condenser system, as for.

instance through the gas pipe 18, an -incon- I densable and chemically inert gas in suflicient quantities to create a substantial pressure within the apparatus; An economical method of effecting this result is fully described in the atent to Edgar M. Clark No. 1,129,034. f the still and condenser system be thus charged with gas under pressure, the liquid body within the still is prevented from distilling over until it has been raised in temperature to the point required to begin the conversion. lVhen this temperature (which is dependent u on the pressure maintained in the apparatus? is attained the liquid contents of the still begin to suffer chemical changes by which they are in part converted into lighter and lower boiling point constituents, and such reaction products accompanied and diluted by a greater or less proportion of vapors which have not been decomposed to the full extent desired, pass out through the vapor line 3 and into the base of the fractionating column 4. In their passage upward through the column these vapors are fractionally condensed, the condensate serving to fill the pans 6 and continuously overflowing from each upper pan to the next lower pan and finally into thebase of the column, from which the condensate drains through the pipe 11 back to the still 1. Byreason of the inverted siphon 12 this reflux condensate becomes heated to the temperature existing in the still by being carried through the liquid body therein and is then discharged near the top of the still. Should there be any water in the reflux condensate it is therefore introduced in such a manner as to avoid thumping.

Vhen the series of pans 6 in the fractionating column 4 has become filled with liquid the outgoing vapors are compelled to bubble through the liquid in these pans successively in order to reach the top of the column. The pans and the liquid bodies therein are automatically maintained at progressively decreasing temperatures from the base to the top of the column, and the condensate in each pan is of correspondingly dilferent gravity and boiling point. By reason of the thorough-washing and extensive surface contact of the vapors with the several liquid bodies, we find that there is effected an exceedingly accurate fractionation. The column is so proportioned and its condensing capacity is such that the liquid body in the lower pan 6 does not at any time in the normal operation of the apparatus contain any appreciable proportion or percentage of the low boiling point or light constitutents which are to constitute the net resultof the process, so, also the contents of the top an 6 will be substantially an oil slightlyhi er in boilingpoint than the end ractions of the resu t of the process. The intermediate roduct which is to constitute the net p to aaim all novelty inherent in our invert-- pans will contain in varyi proportions, heav and light or high boiling point and low oiling point fractions or constituents.

The vapors which escape condensation in the column 4 or which are redistilled from the upper pan 6 thereof, pass outwardly through the line 13 and are condensed in the water cooled condenser 14, draining from the latter into the receiving drum 16 from which they are withdrawn at such a rate as to maintain a free space above the liquid level in the drum.

The pressure within the a paratus will be controlled through the s pipe 18, this pipe serving to vent from tfi: system any excess quantity of incondensable gas formed therein, or to convey into the system incondensable gas from some other source should the production of gas within the system fail at any time to answer the predetermined pressure requirements therein. A simple method of accomplishing this pressure control through the as-escape pipe 18 is illustrated and descri ed in the patent to Edgar M. Clark above referred to.

The process heretofore described isof the greatest technical advantage whenapplied to the pyrogenesis of gasolene, i. e., themixture of aliphatic hydrocarbons mainly of the saturated series and boiling between 80 and 400 to 420 F., from the heavier or higher boiling point constituents of crude petroleum. such as fuel oil. gas oil and the other relatively heavy products or residues of refinery processes boiling in large part at and above 500 F.

As a specific example of the process above described the following may be given:

A still of a capaclty of 200 barrels is provided with a fractionating column of the design shown in the drawing, 6 feet in diameter and 30 feet in height and provided in its interior with 20 pans, the li uid depth in each pan being 6 inches. is still is char d with a petroleum oil or troleum resi ue, the fractions of which boll between 450 and 750 F., the mixture having a Baum gravity of about 30. The distillation is conducted under a pressure of 5} atmospheres.

While we have described in considerable detail the s ific form of apparatus which we find wel adapted to the carrying out of our improved process, as well as the details of a particular commercial process in 'ac-' cordance with the invention, it will be understood that this is illustrative only and for the purpose of makin clear the nature and mode of applying invention and that the invention s not to be regarded as limited in scope to the illustrative details given except in so far as such limitation 'is included within the terms of the nonbinclaims in which it is our'inlfiention ficiently and maintained cracked Vapors tion as broadly as is permissible in view of t e prior art.

hat We claim as new and desire to secure by Letters Patent is- The improvement in the art of cracking petroleum oils by distillation under pressure which consists in passing the mixture of sufficiently cracked and insufficiently cracked vapors continuously produced within the still through a plurality of separated bodies of petroleum oil arranged in series at temperatures such as to condense all insufficiently cracked fractions but not to condense the sufficiently cracked fractions, and condensing and collecting the sufficiently crackedfractions which escape condensation in the said liquid bodies.

2. he improvement in the art ofcracking petroleum oils by distillation under pressure which consists in passing the mixture of sufficiently cracked and insufficiently continuously produced within the still through a plurality of separated bodies of petroleum oil arranged in series and maintained at tem eratures such as to condense all insufficient y cracked fractions but not to condense the sufficiently cracked fractions, condensing and collecting the sufcracked fractions which escape condensation in the said liquid bodies, and continuously returning to the still the insufficiently cracked fractions condensed by the said liquid bodies.

3. T e improvement in the art of cracking :petroleum oils.by .distillation under pressure which consists in passing the mixture of sufficiently cracked and insufliciently cracked vapors continuously produced within the still through a succession of liquid bodies of petroleum oil maintained at temeratures such as to condense all insufliciently cracked vapors but not to condense the sufliciently cracked fractions, the said liquid bodies being connected and discharging one into the other, in a direction opposite to the flow of vapors, and separatel condensing and collecting the sufficient y cracked fractions escaping condensation in said liquid bodies.

4. The improvement in the art of producing gasolene hydrocarbons from relatively heavy hydrocarbons which consists in subjecting such relatively heavy hydrocarbons to distillation under a pressure upward of 4 atmospheres, passing the mixture of sufficiently and insufficiently cracked vapors continuously produced within the still the su liquid bodies being connected and dischargthrough a succession of liquid bodies of petroleum oil maintained at temperatures to condense all non-gasolenelike hydrocarbons and not to condense the gasolenelike hydrocarbons, and separately condensing and collecting the gasolenelike hydrocarbons.

5. The improvement in the art of roduc ing gasolene hydrocarbons from re atively heavy hydrocarbons which consists in subjecting such relatively heavy hydrocarbons to distillation under a pressure upward of 4 atmospheres, passing the mixture of sufficiently and insufficiently continuously produced within the still through a succession of liquid bodies of petroleum oil maintained at temperatures to condense all non-gasolenelike hydrocarbons and not ta condense the gasolenelike hydrocarbons, separately condensing and collecting the gasolenelike hydrocarbons, and continuously returning the condensed nongasolenelike hydrocarbons to the still.

6. The improvement in the art of crack ing petroleum oils by distillation under pressure which consists in passing the mixture of sufliciently cracked and insufficiently cracked vapors continuously produced Within the still through a succession of liquid bodies of petroleum oil maintained at temperatures such as to condense all insufficientl cracked vapors but not to condense ciently cracked fractions, the said 111g one' into the other in a direction opposite to the flow of vapors, separately condensing and collecting the sufficiently cracked fractions escaping condensation in said liquid bodies, and maintaining the entire system, including the final condenser for the cracked fractions under the same ressure.

7. The improvement in the art 0 producing gasolene hydrocarbons from relatively heavy hydrocarbons which consists in subjecting such relatively heavy hydrocarbons to distillation under a ressure upward of four atmospheres causm" the vapors of the sufficiently cracked fractions to pass through a plurality of separated bodies of petroleum oil arranged in a series'maintained at successively lower temperatures, that of the final body being sufficient to pass the asolene of the desired constitution and condensing and collecting the fractions which pass through said liquid bodies.

FRANK B. LEWIS. THOMAS'S. COOKE.

cracked vapors DISOLAIMEQB 1,392,584.-Frank B. Lewis and Thomas S. Cooke, Whiting, Ind.; An or Dxs'rnmmp Pmonbnu 0114!. Patent dated October 4, 1921. Diacla-nmer filod Apnl 18, 1936, by the assignee, Slandani Oil Company.

'Hcrcby en'tera this disclaimer to that part of the specification which constitutes claima1,34,56and7.

idpwi dud, May 1:, 1936.]

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