US2185070A - Process of hydrogenating hydrocarbon oils - Google Patents

Description

93 E. w. STEVENS 2,135,070

PROCESS OF HYDROGENATING HYDROCARBON OILS Filed Jan. 31, 1939 Patented Dec. 26, 1939 Pnocsss or nrnnoennsmc coN onts Elbridge Webster Stevens, Baltimore, Md., assignor, by mesne assignments, to Wachovia and Trust Company, Forsyth County, N. 0., a.

corporation Application January 31, 1939, Serial No. 253,915

7 Claims. (01. 196-53) jecting the vapors of the heavier or higher boiling petroleum oils with hydrogen, to catalytic action in the presence oi or'withinan electrostatic fielti, with the catalysis material in the form of a Venturi-shaped tube or other mixing means, through which the vapors or gases pass so as to intimately contact the petroleum vapor andhydrogen, with simultaneous electric treatment to form a new, permanent compound or compounds or the nature of lower boiling petroleum oils with higher octane rating.

Crude oils as it comes from the ground consists of liquid hydrocarbons of the cnH2n+2 series, containing from ten to twenty percent of gasoline, a like percentage of kerosene, about five percent of gas oiland the'remainder of from fifty to seventy percent fuel oil, suitable only for burning under steam --boilers and for general heating purposes.

In recent years a process known as cracking has been practiced with these heavier hydrocarbon oils with the result that the production 01 approximately another twentypercent of gasoline is to be obtained irom'the original crude 011.

But while this treatment resulted in an additional yield of gasoline, the residue of these heavier oils so treated were rendered less marketable, large percentages of the heavy fractions being turned into non-condensable gas and carbon.

In the practical use of the present invention, there are made use of facts and practices which have not heretoiore been rec as essential to the accomplishment of the art, resulting in a degree of efliclency and of a higher yield of gasoline of asuperior quality than has heretofore been possible.

As is well known, gasoline contains very little more hydrogen than does kerosene and the heavier oils. Below is given a table showing the chemical composition of the constituents of crude oil:

N 5 i301 o gl t me 08? n Y y to m wei ht) (b wefifl) sesssassasasssasss No'nodecane .I.:

It is thus seen what a small amount of hydrogen is-required to convert some of the heavier fractions of the crude oil into the lower boiling compounds. For example, heptane, which is considered the principal ingredient of gasoline, contains but 51/100 of'one percent more hydrogen than does decane, the principal constituent of kerosene.

The accompanying drawing illustrates dia-v grammatically apparatus by means of which the present process may be carried out.

In the practice of the present invention and referring particularly to the apparatus illustrated in the drawing, thereis employed a furnace i for heating the series of coils 2 of the pipe still. A suitable ofl or gas burner 3 is made use of for heating the furnace. Crude oil or other liquid hydrocarbon is pumped from storage through pipe 6 and may enter the third or fourth tray of a dephlegmating bubble-cap type column 5. A float valve 6 of suitable form is coupled by the top and bottom pipes I with the lower part of the column 5 whereby the liquid level in the lower part of the column will effect movement of the float and actuate the valve 8 in pipe line a through the medium of the coupling 9, and when thel line I similar to a venturi.

full. However, the reflux from the trays above will account for most of the contents of this chamber. This reflux, representing the heavier fractions of the oil which have not as yet been turned into gasoline, and the crude oil admitted by way of pipe 4, are pumped through pipe I l to the heating coils 2, or the'crude oil may be introduced into the system directly into this pipe H so as to pass directly to the first coil of the still.

When this oil has become vaporized by circulation through a sufllcient number of turns of the first of the heating coils 2, the vapor first enters the lower chamber of one of a series of catalysis converters which are indicated by the characters Cl2, 0-43 and C--l4 where the vapor receives a given amount of a mixture of hydrogen and hydrogen-rich gas, as will be more fully hereinafter described. The entrance of both the hydrocarbon vapor and the hydrogen and hydrogen-rich gas is made preferably tangentially so as to give to them as thorough a mixing one with the other as is possible.

In each of the converters the catalysis material is in a form which will bring about a close commingling of the molecules of the difierent gases and vapors passing from one heating coil to the other and from the top coil to thecondenser. The object in having the material in this form is to bring the atoms of the different molecules into as close contact with one another as possible while at the same time having them in close proximity to or in contact with the catalytic material. In the diagrammatic illustration of the apparatus the catalysismaterial in each converter is in the form of a double conical tube or atube generally respectively for thevconverters V-l2, V-l3 and V--l'4. The outlet of the first of the coils of the'series 2 in the furnace enters the first converter C-l2 in the lower part thereof and the lower end of the second coil leads from the upper part of the first converter and into the lowenpart of the second converter. This procedure is repeated with respect to the coils and converters, as is clearly shown, and each converter is partioned in a plane passing through the constricted part of the tube therein so that the entering vapors will be compelled to pass through the tube before leaving the'upper part of "the converter.

Extending through the longitudinal center of each convertertube is'an insulated high-tension electrode by means of which an electric field may be set up in each converter tube, however, the

electric impulses impressed upon the mixed mdlecule s of thevapors may also be impressed upon the mixture of hydrocarbon vapors and hydrogen by any other of the wellknown electrical devices generally used, with or without an insulated central electrode. These electrodes are designated respectively for the several converters El2, E--l3 and EI4.

The hydrocarbon vapor, having had the hydrogen and hydrogen-rich gas added and the mixed gases having received a high voltage, high-frequency charge ofelectri'c current of an accurately determined potential when passing through the catalysis tube -V-i2 and at a temperature just above vaporization or below a cracking temperature of the hydrocarbon oil, then passes from the first converter through the second oneof the series of heating coils 2 which is maintained at a higher temperature so that the temperature'of the mixed'vapors will be increased but will still be kept below a crackingtemperature. Here the combined hydrocarbon vapor and hydrogen- These tubes are designated rich gas undergoes a fixing but not a disrupting of its molecular structure.

The vapor-hydrogen mixture then enters the second catalysis converter.C-l3, where it may or may not have additional hydrogen and hydrogen-rich gas added as before, and is subjected to another electrical charge of high-tension, highfrequency current and passes on to be fixed again in the next one of the furnace coils 2 and at a. still higher temperature but below a cracking heat. 5

The vapor-hydrogen-rich gas finallyreceives the last electrical catalytic hydrogenation treatment in the converter 0-44, from the top of which it passes by way of the pipe l5 into the upper part of the cooler It to be cooled for efiicient dephlegmating-column action where the gasoline fractions that have been formed are removed and the dephlegmated reflux is then returned for recycling.

The numeral l1 designates a tank from the upper part of which the non-condensable gases are taken off for recirculation through the system, which non-condensable gases have heretofore been referred to as hydrogen-rich gas. A suitable pump l8, connected with the tank I! by the pipe line l9, accomplishes this function, transferring the hydrogen-rich gas through the distributor pipe 20 to the several converters.

The hydrocarbon oil fractions after being partly cooled in their passage through the cooler l6, enter the lower part of the dephlegmating column by Way of the pipe 21 where the newly made gasoline is separated, the gasoline vapor leaving the top of the column through the pipe 22 to be condensed into liquid by a suitable water-cooled condenser 23, after having the non-condensable gases removed from the liquid gasoline in the separator tank l1, goes on to a suitable storage receptacleby way of the pipe 24. In the manner well known to the art, gasoline is pumped to the top tray of the column 5 by a suitable pump such as is indicated at 25, through the pipe 26 for the proper control of the refiux to regulate. the end point of the gasoline produced. 'It is also well known that the reflux from thetrays of the column finally reaches the chamber at the lower part of the column for recycling through the pipe still by way of the pipe line H and through the catalysis converters with which the still is connected..

The temperature of the hydrocarbon vapor as it passes intothe first converter 0-42, is about 575 F. It enters the second converter at about 600 F. and the .third converter at about 675 F.

These temperatures may be varied to suit different oils by regulating the furnace operation or by any other means which might be employedfor vaporizing the hydrocarbon. Generally there is employed an electric potential of between 2000 and 3000 volts and having an oscillation period of between 20,000 and 40,000 cycles per second, producing a silent dark discharge which is impressed upon the vapor and hydrogen-rich drogemrich gas is admitted to each converter in proportion by weight of the hydrogen vapor treated.

I have found that hydrogenation of petroleum oil vapors takes place in two separate and dis- The expansive force of the heat employed in the vaporization of the oils in order that the molecules of the saturates and unsaturates can become loosened from each other as readily as possible, but immediately the additional hydrogen is introduced to form the desired lower boiling point fractions, slight pressure is desirable, as according to the law of mass action, reaction velocity is proportional to concentration and concentration is directly proportional to pressure.

In the present invention, the vaporizing of the heavy hydrocarbon oils is accomplished with very low pressure; but immediately after the addition of hydrogen to the vapor, the mixture of the two receives a slightly increased velocity when passing through the double conical. tube of the catalytic converter. The reaction desired is greatly assisted by the catalytic material of the tube.

In using the constricted tube to crowd together the atoms of the molecules of the mixed gases whereby there is effected a closer association thereof for the chemical addition of the hydrogen to the hydrocarbon vapors of high-boiling point fractions to those of lower boiling point fractions, such crowding action is not transmitted through the whole system. This allows the primary heat disruptive reaction, which slightly loosens the molecules from each other, to proceed under the most advantageous condition. This absence of high pressure allows the entire apparatus to be constructed of. light and simple materials of relatively cheap construction and design.

I am aware of existing claims having been made in the existing patents of Robertson #1,238,339 and Cherry #1,229,886, likewise Schmidt and Wolcott #1,307,93l, for the decomposing, of liq-' uid hydrocarbon vapors to form light from heavy hydrocarbons, and I, in a former patent, #1,347,119, used a sparking electric discharge to keep a catalysis clean and active, but I believe I am the first to use high-tension electric currents in whichthe frequencies employed are correlated with the particular catalysts used to assist such catalytic material to perform the act of saturating the unsaturated hydrocarbons present, in the closely confined space created by the shape of a constricted tube without raising such hydrocarbon vapors to cracking temperatures, and carrying out the treatment in separate steps, 'each at a higher heat than the previous one, to effect the final conversion, then separating the converted hydrocarbon vapors from the ones not sufficiently converted, and recycling them for further treatment until final conversion takes place and hydrogenation is accomplished without cracking having taken place at all, which results in the proper rearrangement vof the molecules and gives to the gasoline so desirable results when converter 0-42 operates at 575 n, C-l3 at 600 an, and-c-u at cre m, while if a nickel or molybdenum catalysis tube material is used, electric currentoscillationsof from 30,000 to 35,000 per second produce the best result. These temperatures are imparted by the heated vapors to the catalytic material tubes and the desired action of the catalytic'materials is obtained at the vapor temperatures. When it is necessary to increase or lower the temperatures in the converters, that is, the temperatures of the 'catalytic material, such changes are accomplished by increasing or decreasing the furnace temperature. Thus if the furnace temperature is raised, the temperatures of the vapors in the coils 2 will be correspondingly raised, the highest vapor temperature being in the top coil and the lowest inthe bottom coiland such vapor temperatures will be passed on to the tubes of catalytic material. I have found that it is only by correlating the electrical frequencies with certain catalysis materials and a certain degree of heat that good gasoline, and with high octane rating and without undesirable polymerized constituents, .can be produced at the low temperatures used. I I

As an illustration of the foregoing, good results are obtained when operat ng the system while discharging current from the electrodes at the .different percentages at the different temperatures given in association therewith for the converters seem to work best w th the proportions stated for the catalyst materials. 'Nickel might be substituted for-the aluminum but the iron and zinc proportions remain the same. With higher temperatures and higher frequency of electric current, less iron is required and more nickel or aluminum.

Wh le the process described andillustrated diagrammatically sets forth the recycling of the noncondensable fractions with hydrogen gas, the process may be effectively carriedout by the introduction .of pure hydrogen gas into each converter without admixture with the uncondensed gases or fractions recovered from the separator 11.

Although the hydrogen gas may be introduced at any place in the system between the. converters and the separating tank I! or at the converters, as stated, it is preferably ntroduced as illustrated by coupling a high pressure cylinder H of the gas with the upper part of tank I! by the pipe 21 in which a suitable. metering valve 28 is interposed. Thus the flow of the hydrogen into the tank for mixture with the non-condensable gases may be accurately controlled, as is necessary for the most eflicient operation of the process.

What is claimed is:

,1. The process of converting heavy petroleum oil fractions to lighter fractions, which comprises vaporizing the heavy oil fractions, mixing the heated vapor with hydrogen gas, passing the vapor-gas mixture through a space encircled by a catalytic material, producing a high frequency silent dark discharge of electric current through said space, raising the temperature of the vaporgas mixture so treated above the original temperature of the vapor while maintaining the treated vaporgas mixture below 680 F., and again passing the vapor gasmixture through a high frequency electric field forming a silent dark discharge in a space enclosed by a catalytic material. t 4

2. The process of converting heavy hydro-carbon oils to lighter fractions, which comprises vaporizing such oils, passing such vapor at a temperature of less than 600 E, into a catalyst chamber, mixing the hydrogen gas with the vapor in said chamber, flowing the gas and vapor mixture in said chamber through a constricted space designed to produce agitation of the mixture, which space is circumscribed by a catalytic material, impressing on said mixture'within the constricted space a non-sparking charge of high frequency electric current, and repeating the steps outlined in successivechambers with progressive increase in temperature in each chamber and constricted catalytic space, the final temperature being not higher than 680 F.

3. The process of converting heavy hydrocarbon oils to lighter fractions, which comprises vaporizing such oils, passing said vapor at a temperature of less than 600 F., through a catalyst encircled space, admitting hydrogen gas with the vapor just prior to its passage through such space, subj'ecting'the mixture of vapor and gas within the catalytic space to a non-sparking high fre-- quency'electric field while maintaining the catalyst at a temperature at least as high as the temperature of the vapor passing through the space, passing the mixture through a second heated catalyst encircled space, mixing hydrogen gas with the mixture just prior to its passage through the second space, subjecting the mixture in the second space to a non-sparking high frequency electric field, and finally passing themixture through a third catalyst encircled space after adding hydrogen gas to' the mixture prior to its'introduction into the third space and subjecting the mixture in the third space to a non-sparking high frequency electric field, the said spaces being composed of catalytic material of different compositions and the electrical frequency of said fields being regulated in accordance with the character of the catalytic materials, and the temperatures of the spaces, the final temperaturebeing not greater than 680 F.

4. The process of converting heavy carbon oils to lighter fractions, which comprises the steps of vaporizing said oils, passing said vapor successively through a' series of catalyst encircled .spaces, the catalyst material of each of said spaces consisting of a mixtureof aluminum, iron and zinc, the proportions of which are different for each catalyst space, introducing I hydro hydrogen gas for admixture with the said vapor prior to its passage through each of said catalyst encircled spaces, subjecting the hydrogen-vapor mixture to the action of a non-sparking high frequency discharge of electric current within each of said spaces, regulating the frequency of the electric discharge in each of said spacesin accordance with the composition of the adjacent catalytic 'materiaLand progressively increasing the temperature to which the hydrogen-vapor mixture is subjected in its .passage through the successive spaces.

5. The process of converting heavy hydrocarbon oils to'lighter fractions, which comprises the steps of vaporizing said oils, passing said vapor successively through a series of catalyst encircled spaces, the catalyst material of each of said spaces consisting of a"mixture of aluminum, iron and 'zinc, the proportions of which.

are different for each catalyst space, introducing hydrogen gas for-admixture with the said vapor prior to its passagethr ugh each of said catalyst encircled spaces, subjec ing thehydrogen-pvapor mixture to the action of a non-sparking high frequency discharge of electric current within each of said spaces, regulating the frequency of the electric discharge in each of said spaces in accordance with the composition of the adjacent catalytic material, and progressively increasing the. temperature to which the hydrogen-vapor mixture is subjected in its passage through the successive spaces, the temperatures employed in the process being within the range of from 575 F.

6. The process of converting heavy hydrocarbon oils to lighter fractions, which comprises converting the heavy oil to a vapor, maintaining the temperature of the vapor under 680 F., mixing hydrogen gas with the vapor, passing the vapor gas through a passage of catalytic material having the form of 'a venturi, and discharging non-sparking high frequency current within the passage from, a central electrode to the catalytic.

material while the mixed gas arid vapor is pass ing through the passage.

'7. The process of converting heavy hydrocarbon oils to lighter fractions, which comprises heating the heavy oil to convert the same to a vapor, maintaining said vapor temperature at not more than 680 F., mixing hydrogen gas with the vapor, and immediately passing the vapor gas mixture through a passage of catalytic material having a constriction therein, and simultaneously with the passing of the vapor gas mixture through said passage discharging non-sparking high frequency current from the central part of the space in the constricted portion" thereof to the wall of the passage.

EL'BRJDGE WEBSTER STEVENS.

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