US1974303A - Treatment of hydrocarbon oil - Google Patents

Description

Sept. 18, 1934. A, FISHER 1,974,303

TREATMENT OF HYDROCARBON OIL Filed Jan. 25, 1932 CONDENSER Y RECEIVER COMBUST'ON INVENTOR ALFRED FISHER BY 4/ WOZE Patented Sept. 18, 1934 1 Q U E STATES} 1,974,303 TREATMENT OF HYDROCARBON Q11 Alfred Fisher, Chicago, 111., assignor to Universal Oil Produets company, Chicago, 111., a'corporationof South Dakota,

Application January 25, msa iserial No. 588,534

3 Claims; (01. 196-67)" This invention relates to the treatment of hy-- drocarbons',-and more particularly refers to-an improved 'processand apparatus for the reduction ofresidual oils resulting from cracking to substantially devolatil-ized coke, the simultaneous reforming or" uncondensable hydrocarbon gas, from the same cracking operation, by its own partial combustion, and utilization of the highly heated reformed gas to furnish heat for, and

110 otherwise assist, the coking operation.

' I am fully aware of processes in commercial use for thereforming of gases of relatively high calorificvalue by their own partial combustion or oxidation to produce gas of lower calorific value gl5 for industrial and domestic purposes.

' sure by direct contact of said residual oil with aheat carrying medium, such as reheated inter-.' mediate products of the cracking operation, low boiling distillates, gas, et cetera.

The present invention is concerned with an 125 advantageous combination of gas reforming and residual oil carbonization methods operated in conjunction with a cracking process whereby the ,heat attained *by the residual conversion products and the heat attained by the reformedgases 'of the cracking operation is utilized to effect coking and substantial devolatilization of said residual oil; accomplishing, in .a .singleunified operation, the conversion :ofhydro'carbon 'oil to :produce good quality motor fuel, gas suitable for domestic and industrial purposes and substantially "devolatilized coke. 7

One specific embodiment of the'invention may comprise subjecting a hydrocarbon oil to. con- .version in a cracking system whereby low boiling distillate, uncond'ensable gas of relatively high calorific value and residual oil are produced, introducing said residual oilwith'out intentional and substantial loss of heat 'into a coking zone, preferably maintained at substantially atmos- 5 'pheric 'or relatively low superatmospheric pressure, reforming or decreasing the calorific value of said uncondensable gas by its own partial com fbustion and introducing the highly heated prod- ;uct into said coking zone to assist coking and efiect substantial devolatilization of said residual oil.

jfThe accompanying diagrammatic drawing i1- lustrates one specific form of apparatus wherein the process of the present invention may be H 5 accomplished. Raw oil charging lor the system may be supplied through line 1 and valve 2: to pump 3 from which it is fed throu h line 4 and. may pass, all orin part, through line 5 and valve 6 into fractionator 7 or, all or in part, through line, 8, valve 9 and. line 10 direct to heating element 1.1. The raw oil supplied to, the fractionator is. preheated by direct contact with the cracked vaporous products in-this zone and assists in condensing their relatively heavy components collecting therewith in the lower portion of the fractionator to be withdrawn through line 12 andv valve 13 to pu 14, from which the combined feed (preheated raw oil and reflux condensate) is supplied through line IQ and valve 15 to heating element 11; A furnace 16 of any suitable form supplies the required heatto the-oil passing through heating element, 11 and the heated oil is dis charged at the desired conversion temperature and preferably at substantial super-atmospheric pressure through line 17 and valve 18 into reac tion chamber 19.

Chamber 1-9 is a zone of substantial superatmospheric pressure wherein conversion of the heated material from heating element 11 -may continue and wherein the vaporous and non- 'vaporous conversion products are Sep rated,

The residual liquid conversion products are withdrawn from'chamber 19 through line 39 and a portion thereof may, if desired, be withdrawn from the system through line 40 and valve 4-1 to cooling and storage, .or to any desired further treatment. All or a substantial proportion of this product, however, is directed "without substantial loss of heat, through line 42 and valve'43 into coking chamber 44 or through line 42 and valve "43 into coking chamber 44, The vaporous products from chamber 19 pass through line .20 and valve '21 to fractionation in fractionator 7.

The insufficiently converted relatively heavy components of the vapors suppliedto-fractionator "'7 are condensed within this zone to be returned, as already described, to heating element li-for further conversion. The relatively light desirable components of the vapors and uncondensable gas pass from the fractionator through "line 22 and valve 23, are subjected to condensation and cooling in condenser '24, from which the resulting distillate and uncondensable gaspass through line i25and valve 26 to be collected in receiver 27.

Distillate may be withdrawn from the receiver to storage or to further treatment, as desired,

'throughline .28 and valve 29,. .Apcrtion of the 'uncon'densabie :gas may be released from the receiver through line '30 and valve 31. However,

at least a portion, if not all, of the uncondensable gas produced by the cracking operation is withdrawn from receiver 27 through line 32 and valve 33 to combustion zone 34 wherein the well known reforming operation is accomplished. Air or other oxidizing gas is supplied through line 35 admitted to the combustion zone by means of pump or compressor 36 through line 37 and valve 38. The calorific value of the gases is decreased to the desired extent by their partial combustion,

which also serves to heat the gases to a relatively high temperature. The heated reformed gas passes from combustion zone 34 through line 45 and is introduced into chamber 44 through line 46 and valve 4'7, or into chamber 44 through line 46' and valve 4'7.

Coking chambers 44 and 44 aresimilar zones of substantially reduced pressure relative to that employed in chamber 19, which may be operated simultaneously or, preferably, are alternately operated. It will be understood that only one such zone or any number of a plurality of coking chambers may be employed without departing from the scope of the invention. Preferably, however, while one chamber is in operation and is being filled with coke, another is being cleaned and prepared for operation, and when the chamber in operation has become substantially filled with coke it is isolated from the system for cleaning while the chamber prepared for operation is brought into use.

The highly heated reformed gas from'combustion zone 34, as here illustrated, passes upward through the mass of residual material in the coking zone counter-current to the stream of incoming residual oil, by means of which a substantial proportion of its heat is dissipated to the residual material, effecting reduction of the latter to substantially devolatilized coke. The vaporous and gaseous products are withdrawn from coking chambers 44 and 44, through lines 48 and 48, respectively, controlled by the respective Valves 49 and 49', discharging them to line 50.

Inasmuch as the gases and vapors evolved from the residual material during the coking operation will normally increase the calorific value of the total gases passing through the coking zone above that of the reformed gases introduced thereto, it may be desirable to reoirculate -a portion of the vaporous products from the coking zone to the combustion zone in order to better control the calorific value of the resulting product. This may be accomplished by diverting any desired proportion of the vaporous products from line 50 through 1ine51 and valve 52 to pump 53, from which they are supplied through line 54 and valve 55 to combustion zone 34. In this manner gases of the desired calorific value may be withdrawn from the system through valve 56, in line 50." On the other hand, when there is a substantial proportion of liquefiable hydrocarbon vapors Within the gases withdrawn from the coking zone, it may be desirable to subject them, by well known means (not shown), to scrubbing or absorption for the recovery thereof, in which case, by regulating combustion of the gases from receiver 27 in combustion zone 34, the calorific value of the gases entering the coking zone may be maintained sufiiciently low to warrant appreciation of its calorific value by the gases evolved from the residual material during the coking operation, and conditions may be so controlled to permit removal of a gas from the scrubbing or absorption means of the desired calorific value for domestic and industrial purposes.

bustion step. I

In an apparatus such as above illustrated and described, the cracking portion of the system may utilize substantially equalized or differential pressures ranging from 100 pounds or thereabouts to 500 pounds or more per square inch. Conversion temperatures at the outlet from the heating element may range, for example, from 800 to 1,000 F., or thereabouts. The temperature attained by the gas undergoing reformation may range, for example, from 1,000 to 2,000 F., depending primarily upon the calorific value of the gas from the cracking system and the desired calorific value of the final gaseous product. Substantially atmospheric or relatively low superat- 'mospheric pressures below 100 pounds or thereabouts per square inch are preferably employed in the coking zone and the temperature attained in this zone may range, for example, from 900 to 1800 F., or thereabouts, depending primarily upon the temperature of the reformed gas utilized as the heat carrying medium. 7'

As a specific example of the operation of the process of the present invention, as it may be practiced in the apparatus illustrated, -a 22 A. P. I. gravity Mid-continent fuel oil isthe charging stock supplied to the system and it is heated, together with reflux condensate from the fractionator of the cracking process, to a tem-'- perature of approximately 900 F. under a super atmospheric pressure of approximately 250 pounds per square inch. v Substantially this same pressure is maintained throughout the cracking portion of the system. Residual oil is withdrawn from the reaction chamber substantially as fast as it collects within the lower portion of this zone and is introduced into the coking zone at a temperature of approximately 750 F.

The cracking operation may produce approximately 68% of material boiling within the range of motor fuel, with an anti-knock value equivalent to an octane number of approximately '60. The gas produced by this operation, amounting to approximately 650 cubic feet per gallon of charging stock and having a calorific value of approximately 1400 B.t.u.s per cubic foot, is reformed by its own partial combustion to a gas having a calorific value of approximately 400 B.t.u.s per cubic foot. The resulting volume of reformed gas is approximately 3 /2 times the original volume. The reformed gas enters the coking zone at a temperature of approximately 170 0 F. The coking operation may result in the production of about pounds of coke, per barrel of raw oil charging stock supplied to the system, having a volatile content of less than 3% and of rather porous structure, but exceedingly hard and having good structural strength.

I claim as my invention:

1. In the cracking of hydrocarbon oils wherein the hot cracked oil is separated under pressure into residual oil and a mixture of vapors and gases and the vapors separated from the gases by condensation, the method which comprises re ducing the pressure on the residual oil while hot to effect distillation thereof, subjecting at least a portion of the separated gases to partialcombustion to reduce the calorific value and increase the temperature thereof, and introducing the thustreated gases into contact with the residual oil being distilled to coke the latter.

2. The method as defined in claim 1 further characterized in that vapors and gases formed in the coking step are supplied to the partial comcracking zone and distilling the same therein, subjecting at least a portion of the separated gases to partial combustion to reduce the calorific value and increase the temperature thereof, and. introducing the thus treated gases into contact with the unvaporized oil being distilled in said distillation zone to assist the distillation thereof.

ALFRED FISHER.

Images