US1643036A - Method of and apparatus for treating hydrocarbons - Google Patents

Description

Se t. 20192 p 7 `c. P. ToLMAN METHOD 0F AND APPARATUS FOR TREATING HYDROCARBONS Filed Aug. 26, 1926 mwN.

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Patented Sept. 20, 1927.

PATENT OFFICE.

CHARLES 1. -'.I.OIB[A1\T,.OIF KEW GARDENS, NEW YORK. v

METHOD OF AND APPARATUS FOR TREATING HYDROCARBONS.

Application tiled August 26, 1,926. Serial No. 131,'5'.l

My present invention relates to the treating of hydrocarbons by heat with the View either of simply distilling same or and more particularly, of obtaining therefrom, by

5 cracking, hydrocarbons having a lower molecular weight than the starting material.

l In the heat treatment-of oil or other hydrocarbomit is very important not to overheat portions thereof,` as by so doing excessive amounts of carbon and gas are formed which not only represent a waste of the hydrocarbon, but particularly in case of the carbon, present a serious problem in their removal from the system. For this reason and others it has been proposed to heat hydrocarbon oil by commingling therewith a heating fluid whose temperature can be accuratelycontrolled in contradistinction to heating by means of fireheated stills an/d the like which commonly produce local'overheating. The mode of heating mentioned has the further advantage that the heating fluid can be mixed intimately with the oil` and hence impart to it a uniform degree of temperature. After long study ofthe problem I have been led to choose mercury or an equivalent substance, as a highly desirable vehicle for imparting the heat necessary for the cracking or other heat treatment of the oil or other hydrocarbon. The reasons for the selection of mercury for this purpose are chiefly as follows:

1. Its vaporizing characteristics are such that the comparatively high temperature necessary for cracking can be obtained without excessive pressure, and its vapor can be superheated and the relation between temperature and pressure thereby divorced.

2. It is easily condensed, and in contrast to steam, for example, it thus greatly re- -lieves the condensers.`

3. It is easily separated from the oil and is returnable to the boiler by gravity.

4. It carries nothing in solution.

5. It exerts a desirable catalytic .effect upon the oil-undergoing treatment. In thus employing mercury for imparting heat to the oil by physically contacting it therewith, a further problem is presented by the fact of the difference in the vaporpressure characteristics of the mercury vapor .greater than that of mercury so that a temperature of 800 F., for example, would produce saturated oil vapor of a much higher l pressure than that corresponding to the mercury vapor, or 45 lbs. perl square inch. Therefore since ordinarily it is the rule to employ cracking temperatures of 800 and above, a fairly high pressure, both of mercury and oil would be contemplated by a simple mixing of the mercury vapor and liquid oil. However, it has been demonstrated by Leslie and Potthoif, see Jour. Am. Chem. Soc., volume 18, .page 776,'and sub- 75 stantiated by applicants own observation that pressure has relatively little effect upon cracking, and hence the very high pressures which have been usual-practice in the art are unnecessary. Accordingly, a feature of so my present invention resides in employing mercury vapor which is superheated prior to its contact with the oil and which is furthermore yunder comparatively low pressures whereby the necessary temperature for a5 cracking may be had without the employment of pressures which have been shown to be excessive. It is thus possible to introduce the heated mercury vapor directly into liquid oil (or solid hydrocarbons), since by/the use no of superheat the temperature of the mercury may be made equal to that of the vaporized saturated hydrocarbon vapors. However, I find if preferable rst to evaporate/the hydrocarbons in an evaporator of common type, but without effecting substantial cracking of such vapors, and then introduce them, together with the superheated mercury vapor into a suitable reactlon chamber wherein the cracking is to take place. This permits low lou pressures to be employed and also has the further advantage t at a portion of the total heat necessary *l'or accomplishingr the conot the system shown is led olf through pipe version ot the oils to be 'furnished by ordinary means, as by directly tired means, or by vvaste heat apparatus, and thus saves the mercury vapor tor the upper and very much more important part ot the heating cycle. Un the other hand, care is talren that the f vaporizing ot the oil is accomplished with substantially no local overheating or craclring, a condition which is easily attained due to the comparatively low temperature involved. Thus, by the arrangement described, the discrepancy of the temperaturevapor pressure is taken care ot While permittingthe use ot loiv pressures.

Liter the vaporiaed (or solid) hydrocarbon has been subjected to the action ot the hot mercury vapor., the resulting vapors are led olii, and condensed, and the mercury separated and returned to the boiler. 'lhe hydrocarbon products are then iiractionally condensed or disposed ot in known ivays tor the obtainment therefrom of their contained gasoline or other desirel product.

lilly invention `will be better understood by reference to the following detailed description taken with the accompanying drawing toi-ming a part .oiE this specification, which shows more or less diagrammatically a system of apparatus tor carrying out my invention.

-et'erring noW to the drawing by characvters of reference: denotes a mercury boiler of known type having a. mercury vapor oiftake 11 communicating with the heating coil or other heating surface of superheater 12, the heat oic which maybe suitably varied. Here the desired amount of superheating is imparted to the vapors. From supcrheater 12 the mercury vapor is led through pipe 13 into the reaction chamber 14. Communicating with the reaction chamber is also the evaporator 17 into which the oil undergoing treatment is introduced through a pipe 18. A. pipe 19 for either steam or a neutral as to assist the `avaporation also communicates' with the evaporating space of the evaporator or boiler 17. A pipe 20 having a valve 32 admits vapor from the evaporator 17 to the reaction chamber 14. To take care of the residue from evaporator 17 a residue tank 22 is provided. Non-return valves, 13 and 20* are preferably provided in ipes 13 and 20 respectively.

he products of reaction from the chamber 14 are led therefrom throughsJ pipe 24.-, thence to condenser 25 and thence to a separator 26 wherein the separation of the liquid mercury from the liqueed hydrocarbons is effected. The liquid hydrocarbon products are removed from the separator 26 y means of a ipe 28 communicating with a receiver 29. ncondensed vapors and gases are also conducted from the separator 26 by means of a, pipe 3D. The final product :intense 31. Mercury is returned to the boiler om separator 2G through a pipe 33 having therein a suitable pump 34', in case suoli should be necessary. The mercury may be introduced into the system by any suitable means as through the extension 33 of pipe 33 beyond the lseparator 26.

-My invention contemplates not only the oraolringof liquid hydrocarbons, including coal tar or liquids derived from the coke industry, but alsothe distillation and cracking of solid substances yielding hydrocarbons as for exam le: shale, oil-bearing sands, materials of ituminous nature such as, sott coal, lignite, etc.

lt will be noted that by virtue of my improved system ot treating hydrocarbons,the temperature may' be maintained at any suitable value depending upon the nature of the material undergoing treatment. '.lhis temperature for the mercury will ordinarily run over 7000 F., and under 11000 F. As previously mentioned, my improved system is particularly adapted to the use of comparatively low pressures e. g. 5U lbs. and under, although l do not limit myself to any particular pressure range. Furthermore, and as has been previously mentioned, the heat necessary 'for bringing about the cracking reaction is furnished substantially entirely by the mercury vapor, this having the eil-'ect of eliminating entirely all danger of local overheating with the attendant production of carbon and gas.

lt will be understood that the foregoing apparatus is illustrative only and accordingly, I have not shown various auxiliary apparatus such as: valves, gages, pipes for venting and draining, etc., which While necessary for the most eiiicient operation of the `system are not required for the comprehension of the invention and furthermore form, per se no part thereof. It will furthermore be understood that various apparatus for fractionally condensing the reaction products and heating the entering oil thereby may be employed if desired.

aving now vdescribed my invention and tliwpzinciple thereof: v i at I claim is: l 1. In the method of cracking hydrocarbon compounds the steps which consist in vaporizing mercury, su rheating the roduced vapor to above t e desired crac g temperature, subjecting the hydrocarbon to i va rizing conditions, but without causing su stent-icl cracking thereof and commingling the hydrocarbon vapor produced with said superheated mercury vapor, said mercury vapor being of such thermal quality as to tem erature and heat units as to oonstitute su stautially the sole source of heat for said crackin reaction.

2 In the met od 0f cracking 'hydrocarhon compounds, the steps which consist in duced with said'superheated mercury vapor vaporizing mercury, su rheatin the roand maintaining@ superatmospherlc total duced vapor to abovet e desire crac 'ng pressure ofthe reacting components below 10 temperature, subjecting the hydrocarbon 50 unds per square inch. f

5 material to vaporizing conditions but with- `n testimony whereof I have aiixed my out causing substantial cracking thereof and signature to this I sczicatiom commingling the hydrocarbon vapor p'o- C LES P. TOLMAN'.`

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