US1553300A - Apparatus for cracking or converting oils - Google Patents

Description

,Sept. 15,1925. 1,553,300

0. AMEND APPARATUS FOR CRACKING OR CONVERTING OILS Filed Aug. 9, 1919 0270 I? rlmend Patented Sept. 15, 1925.

1' UNITED STATES PATENT OFFICE.

O TTO P. AMEND, OF NEW YORK, N. Y'., ASSIGNOR TO H YDBOCABBON CORPORATION, OF

NEW YORK, N. Y.

APPARATUS FOR CRACKING OB CONVERTING 01148.

Application filed August a, 1919. Serial no. 316,440.

To all whom it may concern:

Be it known that I, O'rro P. AMEND, a' citizen of the United States, residing 'in the city of New York, borough of Manhattan,

6 county and State of New York, have invented a certain new and useful Apparatus-for Cracking or Converting Oils, of which the following is a specification.

This invention relates broadly to the art 1 of "cracking crude petroleum, heavy naphthas, kerosene, and higher-boiling hydrocarbon distillates or residuals, and converting the same into lower-boiling hydrocarbons, suitable for use in internal combustion en- 16 gines, and for all other purposes for which the low-boiling petroleum distillates are used. The process is applicable either to hydrocarbons of the paraifin or of the napthene or polymethylene series, or to mix- 20 tures of hydrocarbons of any series. The

process is preferably applicable to any of the higher-boiling petroleum distillates, such as kerosene, Mexican distillates, gas oils, and fuel oils.

The method long-employed in the cracking of these hydrocarbon oils has been carried on in a metal still or tube under pressure exteriorly heated in any one of several ways, usually by means of a flame directed thereagainst. The heat required to pro erly crack the oils is, however, relatively igh, and, when externally applied, necessitates the raising of the temperature of the walls of the still to such degree, in order to properly crack the oil within, that their ability to withstand the pressure within the stillis seriously impaired and there is the great danger present of the walls giving away under the pressure and frequently occasioning the explosion of the still. For these tea-- sons great care must be exercised in the carrying out of this process. By the process of the present invention,

however, I amable to secure any desired suitable vaporizing or cracking temperature Within the hydrocarbons, at the same time the sides and bottom of the still or digester are relatively cool, and the ability of the metal of the containing vessel to resist pressure is consequently not seriously impaired. As :a result, much higher pressures may safeof say from 600 to 1,000 barrels capacity, with my process, whereas, such pressures are not practicable on a scale approaching this I in any process in which the oil is heated by external heating. I secure this result by internal heating of the oil itself, by means of one or more high resistance heating ele-' ments, preferably of carbon, and referably entirely immersed in the oil in t e still or 'gester, and heated to the desired cracking temperature.

One of the chief difliculties experienced in cracking and convertin high boiling hydrocarbons into a low boi ng distillate, by the use of heating elements submerged within the oil and heated to incandescence, consists in the fact that when the element is of any size and is heated to the high heat required for successful cracking of the kerosene or other high boiling hydrocarbons, in the case of kerosene, a heat of from a cherry red to a white heat being generally-required, the heating element repels the oil and prevents intimate contact, and the oil at a distance fromthe heating element was merely vaporized without being cracked or converted into lighter hydrocarbon. The greater part of the condensate obtained is, therefore, nonconverted oil. I have found, however, that to overcome this repellent force of the heating elements, and to enforce contact or close proximity of the oil or oil vapors with such incandescent elements, pressure is required.

The function of pressure in my process,-

while it incidentally raises the boiling point and the'temperature of the liquid, and-although it is primarily to enforce close-contact between the oil or oil vapors and the and on the temperature of the elements, and

on the size of the receptacle. It is obviousthat the more pressure is applied to the oil to keep it in actual contact with the incandescent element, the more cracking and the less vaporization without conversion will take place, and that with an easily cracked oil pressures in excess of four atmospheres should preferably be used, say eighty pounds pressure. With a fuel oil, I prefer to use pressures of between eighty and one hundred and fifty pounds.

I have found that submerged resistance conductors made of carbon are most eflicient, both because of the saturated character of the low boiling condensate obtained by their use, and because any carbon resulting from the cracking of the hydrocarbons, on being deposited on the heating elements does not effect them injuriously, whereas the formation of a hard carbon crust on metallic heaters due to the production of metalliccarbides, causes a disintegration of the heating elements, rendering it unfit for practical use. The heating element employed may be in the form of rods, plates, sheets or tubes, or any other form.

By the use of internal heat electrically app ied, I am able to regulate to a nicety the actual heating within the body of the oil. This more perfect regulation of the heat within the hydrocarbons enables a more constant quality of cracked product to be roduced than is possible with external eating of the still.

The accompanying drawings illustrate an eflicient type of apparatus, forming part of my invention, which may beemployed in practicing the process herein described, although I desire to have it understood that other forms of apparatus may also be used.

Referring to the drawings, the 'figure shows, more or less diagrammatically, partly in section, and partly in elevation, a substantially complete apparatus for practicing the process of this invention.

Referring to the drawings, A is a still having an oil inlet w and an inlet for introducing gas. 6 extending nearly to the bottom of the still. The still is heated by means of a submerged carbo resistance element 0, in the form of a pla e or in tubular form as shown, the said element being provided with suitable terminals 03 and e roperlv insulated from the walls of the st1 1.

Oil is introduced into the still through the pipe 0 which is fed either directly from a pipe at, leading from any suitable source, or from a pipe a through which the oil is forced by a pump a fed from any suitable source. In the ipe a is included a series of preheated coils a" so that the oil, when fed in this manner, is partially heated before entering the still or retort A, for the purpose of minimizing the work required by the elect-rode c.

When current is passed through the electrode c, it is raised to a high degree of heat and assumes a temperature anwhere from cherry red to a white heat degree and pressure being maintained in the still as hereinafter described, the cracking operation on the oil proceeds. The products of the cracking process rise in the still and enter a dome A which is superimposed on the still, and passed ofi' through an outlet B. The stack A is preferably of such height and size that 'during the passage of the products of the cracking operation therethrough sufficient refluxing action will take place as to allow the return to the still of uncracked oil vapors carried along bythe products of the cracking operation, and through such refluxing action raise the quality and quantity of the resulting product.

A further refluxing action may be carried on by inclining the draw-off pipe B in an upward direction, although, if desired, the pipe B may extend in a horizontal direction if the tower A is sufiiciently high to properly carry out its functions.

The draw-off pipe B leads to a series of cooling coils D which are housed by a cas- I ing E, through which a cooling medium,

such as water, is circulated through inlet and outlet pipes e and e. During the passage of products of the cracking operation through these coils, the temperature is sufiiciently lowered to condense the greater portion thereof, although a small percentage of such products remain in gaseous form. Leaving the coils D, the products of the cracking operation pass through a pipe F into a receiving reservoir G. The liquid is trapped out in the reservoir G, but the gases flow oif through pipe It leadin to a tank H. The tank of the reservoir (alias a drawofi' pipe 9' through which the liquids may be passed, drawn-01f, and further treated if desired. A ga e glass 9 is preferably associated with the reservoir G so that one may determine the height of the liquid in said reservoir, and the drawing off of such liquid is preferably controlled by valve g included in the draw-0H pipe 9, and the valve 9 is preferably normally closed.

In carrying out the process of this invention, pressure is maintained within the still during the cracking operation, and I preferi ably maintainthis pressure through back pressure on the still from some portion of the system-beyond the stack A. To this end, pressure valves .or regulators may be included in the system at various points. For example, a valve B may be included in the pipe B as shown, which valve will maintain the pressure in the still, or, if desired, the valve B may be omitted, and a valve F included in the pipe F, though both of these valves may be omitted if the valve 9 is maintained closed, and a valve H included in the gas outlet pipe h. The valves B, .F

and H may be either automatic pressure release valves' or valves of any well known type adjusted to hold back the pressure to the desired degree.

The pressureobtained in the retort is cre ated by and is directly dependent upon the temperature of the heating elements and therefore upon the amount of electric ourrent which is employed in the operation, and is produced by the vaporization, dissociation and .expansion of the hydrocarbons.

In the preferred method of practicing the invention, the gas in the tank H is preferably utilized for preheating purposes, and to this end a pipe 71 leads to a burner I associated with the preheating coils a, and in this pipe is included a valve 2' by means of which the flow of gas may be regulated or cut off as desired.

The pipe I), hereinbefore referred to, is intended for the purpose of initially freeing the retort from air prior to the beginning of the process of cracking.

In commercially employin this invention, the process may be continuous or in termittent as desired. That is to say, oil may be fed steadily to the retort A to take the place of the products of the cracking operation which are continuously passed off, I

or said oil may be fed from time to time as desired.

In the drawings the heating element 0 is shown as of tubular cylindrical cross section, but, in practice, it may well partake of other shapes, such for example, as the form of a plate. Many different shapes may be employed with high efficiency and I therefore do not wish to be understood as limiting the shape of the heating element 0 to that shown. In any event, the heat from the heating element 0 will be imparted directly to the body of the oil in which it is. immersed, and the heating of such oil is not therefore dependent upon the heating of the retort in which it is contained. In practice, it is found that even when the oil is subjected to the highest temperatures, .the

. walls of the retort remain relatively cool,

sene, that is, a hydrocarbon having a range of boilng points above 130 degrees C. and below 260 degrees C. In neither of the well known Burton or Palmer processes can kerosene be commercially cracked, the Burton process serving only to operate upon parafinto'the highly volatile low boiling distillate by my process, and the inability of either the Palmer or Burton processes to successfully crack kerosene, brings out strongly the essential differences between the processes in question.

In instantaneous cracking and dissociation of the hydrocarbons induced by the contact with the incandescent carbonheating element produces a very rapid evolution of low boiling hydrocarbon vapors and rapid resulting increase of pressure. In order to obtain by my process a satisfactory conversion of kerosene into low boiling hydrocarbons, a small still should be used equipped withcarbon conductors of relatively large surface in proportion tothe volume ofoil, and the carbon resistance should preferably be heated to a bright red, or from a bright red to a white heat, although heats as low higher the temperature of the carbon heating element, the lighter in gravity is the condens'ate, and the freer it is from olefines and other unsaturated hydrocarbons, and from coloring matter.

In general, with all the hydrocarbons, the lower the boiling points, the higher is the dissociating temperature which should be used. Dissociation temperatures for as oils and fuel oils of as low as about 500 egrees 0., and as high as a white heat of carbon, maybe used, but with these high boiling oils I prefer to use temperatures from a cherry red to a bright red heat of carbon, or approximately from 750 degrees C. to 1500 degrees C. Pressures in excess of four and under ten atmospheres are sufficient, although higher pressure may be used.

In the foregoing description I have'referred in different places to certain temperatures employed, time periods, etc, but I wish it understood that I do not limit myself to these specific features, nor to the specific de tailsof construction of the apparatus employed. The invention should be construed to cover equivalents, and is to be considered as broadly novel as is commensurate with the appended claim.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

Anapparatus for cracking oil, comprising a stilLadapted to contain a relatively stationarybody of the oil, an electric resistor having an extended heating surface arranged within the still and below the normal liquid heating the preheater by combustion of gases level therein, a condenser and connections including connections fornsupplying gases for conducting vapors from the still to the to the last named means from the gas 001- 10 condenser, means arranged beyond the conlecting means.

5 denser for collecting gases uncondensed In testimony whereof, I sign my name to therein, means including a preheater for this specification. supplying oil to the still, and means for OTTO P. AM'END.

Images