US1872808A - Process of recovering light oils, motor fuel, and the like - Google Patents

Description

Patented Aug. 23, 1932 1;

UNITED "STATES CHARLES J. BAMSBUBG, on EDGEWORTH, PENNSYLVANIA} ASSIGNOR Tomlin norrnns COMPANY, A oon-rorm'rron or PENNSYLVANIA" PROCESS OF RECOVEBQING LIGHT OILS, MOTOR FUEIQAND THE-LIKE No Drawing.

' changes A second object of my inventionis'to provide a process of so treating a petroleum: derivative that upon subsequently cracking said derivative, the light distillates therefrom will 1 0. be of advantageous character-with respect to their use as motor fuel.

A further object of my invention is to provide a process of treating a petroleum derivative containing light aromatic oils, for the recovery of motor, fuel, wherein conversion of such oils into undesirable products is avoided.

A still further object of my invention is .to provide a process for removing gumi-forming or other objectionable constituents from diswtillates of'the character indicated, w thout unnecessary losses.

My invention has other new and useful operative advantages or results as may hereinafter be found to obtain.

Present practice, with regard to the recovery of light oils from fuel gas, is to' circulate over the gas a solvent derived from petroleum, such as gas oil or the like, for the absorption of aromatic hydrocarbon oils from the gas, and subsequently to subject the thereby enriched oil to steam distillation to strip it of said absorbed oils, prior to recirculation over the gas. This stripping process involves extensive apparatus for elfecting-heat exchange, steam distillation, cooling, and re circulation. Further apparatus, including stills, condensers, agitators, etc., and corresponding manipulations, are required for con verting the crude light oil into pure products,

such as benzol, toluol and xylol. 'Moreover,

products 1 combustion motors.

for further objects such Application: filed December 24, 1926. Serial No. 156,9365' PATENT? orFIcE the efiiciency of removal of said. hydrocarbon oils, using a recirculated solvent, is open 7 to improvement.

Mixtures of gasoline and aromatic light oils have been found to be advantageous motor fuels, especially'by reason of the fact that the incorporation of such materials in gasoline produces the desirableeifectof suppressing detonation, when used as fuel in internal For this a reason, J aromatic light oils have been admixed with gasoline and the mixture placed on the market as anti-knock? motor fuel, thusr affording an advantageous outlet for the-sale of such oilsv recovered by gas manufacturers.

With respect to the manufacture of gasoline, it is now commonpractice to crack petroleum derivatives, such as gas oil, in the field,-using pressure distillation processes, some of which produce as much-as 40% of gasoline from gasoil. Thereare, however,

certain disadvantages of cracking gas coil" in the field. The permanent gases produced in the crackingoperation'are useful only as fuel in the plant, and generally no market for their; advantageous sale exists. Furthermore, the residuum from the cracking stills is of practically no value inan oil refinery.

My invention provides for treating fuelgas with gas oil or similar petroleum derivative,

without recirculation, to remove light aromatic oils from the gas, and subsequently crackingthe thereby enriched gas oilto produce an-advantageous motor fuel of the antiknock character. -v a According to my invention, I subject fuel gas to contact with gas oil'in suitable contact apparatus, for the removal of benzol and its homologues. By reasonof-the fact that the gas oil is not recirculated, and comes into contact with the gas substantially free from aromatic hydrocarbon oils, the efficiency of removal of the latter is increased, as compared to the usual-light oil recovery process involving recirculation of solvent. When operating with fresh solvent and without recirculation, the enriched petroleum solvent removed from contact with the gas may contain as much as 8% of benzol hydrocarbons- I'then subject the enriched gas oil to acrackinc jor otherobjectionable or undesirable com-3 ing operation. For this operation, any suit-It will be seen that the washing necesary to able pressure distillation or other cracking process may be employed, for example, the Fleming process, the Dubbs process, or the like." In this stage, the oil or vapors thereof are subjected to extremely hightemperatures under pressure in such manner as to convert a maximum portion of the oil into lighter products, such as gasoline. The distillate from this 'crackingop rati'on, in addition to gasoline, will contain the light oils removed from the of.

In order to remove-gum-forming or other,

objectionable constituents introduced with the aromatic hydrocarb'on'removed from the gas, I subject this distillate to the-usual Washing operations, such as treatmentwith sulphuric acid, caustic sodasolution, fdoctor solution, or the like, especially when losses caused by thorough washing'of the petroleum 'distillates are no't'excessive. 1

'5' The'eracking process may be carried so'far that-a residuum of coke is obtained. The residuum maybe added to the coal being car- 'bonized', orgif coke, to the coke produced in,

the gas plant. In'thismannen the full value of the residuum as fuel may be realized The permanent gases produced in the'cracking operation are conducted into the gas mains, and thus realize their full value. In will beseen that, with an'enrichment equal to about 8% of the petroleum solvent, if the latter is subjected to a cracking operation 'ca-' pable' of'producing of the desired distillat e, such distillate will contain about 16% of 'benzol hydrocarbons, which is a sufficient proportion to produce an anti-knock effect.

i In order to prevent the breaking down of the aromatic oils, such as benzol, into diphenyl pounds, I maysubject the enriched gas oil, prior to the cracking operation, to steam'distillation for the removal of such light oils as will interfere with, or will be undesirably affected by, thecracking operation. This steam distillation may be accomplished in the usual bell-and-tray column, or any otherfsuitable apparatus. -The, gas oil passes downward through the column, in counter-current with steam and vapor,-and is stripped'of substantially all aromatic hydrocarbons. The lat- "ter are condensed, separated from aqueous condensate, washedito remove gum-forming constituents, and added to the distillate from "the cracking operation.

The hot gas oil leaving the'still is run into the pressure stills and is there cracked in the "'usual'manner, thus eflecting a saving inheat units.- The light distillates from the cracking operation are added to the washed condensate from the steam distillation. This'procedure is particularly advantageouswhen the. petroleum distillate is of such character that large "losseswould result from thorough washing.

'moval of light oils, and the recovery of such fuel gas or cracked products therecracking operation.

remove gum-forming constituents introduced with the aromatic hydrocarbons is accomplished out of the presence of the petroleum distillates. The latter may not be washed at all,:or, at most,only a light washing may be given them.

According to my invention, fuel gas may be treated by a simple process for the re-.

light 'oils'is so accomplished that a desirable and readily marketable product, is. obtained at high efiiciency. The invention further provides an advantageous process of cracking enriched petroleum distillate into motor fuel of anti-knock character, with numerous advantages and results as hereinabove set forth.

An alternate or supplementary source of benZol and its homologues available in gas plants, and Within the scope of myinvent'ion', s; is the tarproduced in the gasification'ofcan bonaceous materials, as in coal gas orwater gas manufacture, or the like. Derivatives of such tars may beadded to gas oil priorto V cracking the same for "the purpose of making C an anti-knock motor fuel, whether or not the gas oil contains similarmaterials derived from washing thegas directly. My process is not limited to the use of a particular petroleum oil as solvent, though?-9 gas oil is preferred, nor to any particular means of effecting the various steps, and is to be construed as within the scope of the following claims. 7 V

' I claim as my invention: ,v

1. The'process of obtaining a motor fuel which comprises treating fuel gas containing aromatic hydrocarbons Witha fresh petroleum oil to remove aromatic hydrocarbons therefrom, subjecting the thereby enriched petroleum oil to steam distillation to remove thelighter aromatic hydrocarbons therefrom, subjecting the stripped petroleum oil containing the heavier aromatic hydrocarbons to a cracking operation and mixing the distillate oils from said steam distillation and said 2. The process of obtainingamotor fuel -which'comprises treating fuel gas containing aromatic hydrocarbons with, a fresh-petroleum oil to remove aromatic hydrocarbons therefrom, subjecting the thereby enriched petroleum oil to steam distillation to re- :move the lighter aromatic hydrocarbons therefrom, subjecting the stripped petroleum 55120 011' containing the heavier aromatic hydro-V carbons to a cracking operatiomwashing the distillate oil from said steam distillation to remove gum-forming and other objectionable constituents therefrom and mixing said" washed distillate oil with the distillate from said cracking operation. I f V 3; The process of obtaining motor 'fuel having anti-knock properties which .comprises washing coal gas containing benzene" and other benzenoid hydrocarbons with a petroleum distillate oil for the removal from said gas of said benzenoid hydrocarbons, re-

CHARLES J. RAMSBURG.