US2014212A - Coking hydrocarbon oils - Google Patents

Description

Sept. 1o, 1935. f J, SEGUY 2,014,212

COKING HYDROCARBON OILS Filed April Y30, 1932 LA frac iowa (or Combustion gases and Vaporous hydrocarbons,

resulting from coking of the oil, are removedv from the coking zone through line 2|, valve 22 and are introduced into fractionator or tar separator 23 wherein the heaviest components of the vapors, comprising tars and other materials of high coke-forming characteristics are separated from the lighter vapors and gases. The heavy high coke-forming oils are withdrawn from fractionator 23 .through line 24 and valve 25 to pump 26 by means of which they are returned through line 21 and valve 28 to the manifolds 3, preferably at a point between two of the larger of the nozzles 5, through which the oil from zone 23 is introduced into the coking zone, together with charging stock from line I, and there subjected to further coking.

Vapors escaping condensation in column 23 are withdrawn through line 29 and valve 3|) to further fractionation in fractionator 3| by means of which additional liquid components of the vapors of lower boilingA characteristics than the heavy tars separated in fractionator 23 and of higher boiling characteristics. than the desirable light liquid product of the system are condensed as reflux condensate which collects in the lower portion of fractionator 3| and may be withdrawn through line 32 and valve 33 to cooling and storage or to any desired further treatment, and may, when desired, be recycled to further conversion in the same cracking system from which the residual oil to be coked is obtained, when the oil to be coked is obtained from such a source.

Vapors and gases remaining uncondensed in fractionator 3| are withdrawn through line 34 and valve 35 to condensation and cooling in condenser 36 wherefrom the condensed and uncondensed materials pass through line 31 and valve 38 to be collected in receiver 39. i Uncondensed products, including combustiony gases, hydrocarbon gases and entrained liqueiiable hydrocarbons may be released from receiver 39 through line 40 and valve 4| and are preferably subjected to absorption or scrubbing, by well known means not shown in the drawing, for the removal of the de- Sirable light liquefiable hydrocarbons which may be blended back with the distillate withdrawn from receiver 39 through -line 42 and valve 43, this blended product forming the desirable light liquid' product of the system which preferably comprises materials boiling Within the range of motor fuel and of high anti-knock value. A portion of the gas withdrawn from receiver 39 or preferably a portion of the lean gas from the process, i. e. gas from receiver 39 afterscrubbing or absorption, for the removal of liqueiiable components, may be returned to combustion zone 6 to serve as a portion or all of the fuel required by the process. Line 44, controlled by valve 45, serves as a means of removing gas for this purpose from receiver 39 and line 45', controlled by valve 46, serves as a means of returning the lean gas. Either of these gases thus supplied to pump or compressor 41 are returned through line 48 and valve 49 to burner 9 and thence to combustion zone 6.

Pump 41 may serve as a vacuum pump for maintaining sub-atmospheric pressure in the coking zone and succeeding portions of the system or, when desired, a vacuum pump may be interposed, for example, in line 2| or in line.29 for the purpose of maintaining subatmospheric pressure in the coking zone alone or in the coking zone and any desired portion of the succeeding equipment, although such means are not illustrated in the drawing. v

As already mentioned, the combustion zone mayfbe operated at substantially atmospheric or 5 low superatmospheric pressure up to 60 pounds, or thereabouts, per square inch. The coking zone may be operated at substantially atmospheric orr subatmospheric pressure. Temperatures employed in the coking zone may range from 1200 to 10 1600 F., or thereabouts. The portions of the system succeeding the coking zone may be operated at substantially equalized or increased pressure relative to that employed in the coking zone.

As a specic example of the operation of the 15 process of the present invention, heavy residual oil resulting from cracking is introduced into the coking zone through a plurality of streams of progressively decreasing size at a temperature of approximately 780 F. Hot combustion gases 20 generated under a superatmospheric pressure of about 10 pounds per square inch are passed through the cokingzone and directly contacted `continuously withdrawn from the coking zone and a portion of the lean gas from the system is returned to the combustion zone as fuel. This operation may yield, per barrel of charging stock, about pounds of coke of low volatility, about 35 8 gallons of distillate boiling within the range of motor fuel and having an octane number of approximately 82. The other products of thesystem comprise about 'l1/2 gallons of intermediate Y liquid products suitable for use as cracking stock 40 and about 3500 cubicfeet of gas, per barrel of charging stock. The gas is a mixture of hydrocarbon gases and combustion gases and may have a calorific value of about 500 B. t. u.s

I claim as my invention: 45

1. In a process for the continuous coking of hydrocarbon oil wherein the oil Ais introduced into a coking zone and there directly contacted with hot combustion gases whereby said oil is reduced to coke, the improvement which comprises in- 50 troducing the oil into the coking zone in a plurality of streams of graduated and progressively smaller cross-section, and passing the combustion gases through the coking zone in the direction of decreasing cross-section of said streams. 55

2. A process such as isy claimed in claim 1 wherein subatmospheric pressure is employed in the coking zone.

3. A process for the coking of hydrocarbon oils which comprises introducing the oil into a. cok- 00 ing zone in a plurality of streams of graduated and progressively smaller cross-section, generating combustion gases in a combustion zone and passing the hot combustion products through the coking zone in the direction of decreasing cross- 65 section of said streams, whereby the oil is reduced to coke, removing coke from the coking zone, removing Vaporous and gaseous hydrocarbons together with combustion gases from the 70 coking zone, separating from the mixture of vapors and gases heavy tars and similar coke-forming materials, returning the latter to the coking zone, then cooling the mixture of vapors and gases to condense Vaporous hydrocarbons con- 75 tained therein and returning atleast a portion oi' comprises introducing the oil to the coking zone the latter gaseous hydrocarbons to the combusin a plurality of streams at longitudinally spaced tion zone to serve as fuel for the process. points between said ends of the coking zone, said 4. In the cokingr of hydrocarbon o'il in a cokstreams being of progressively smaller cross-sec- 5 ing zone wherein progressively decreasing temtion in the direction o! decreasing temperatures 5 peratures prevail from one end of the coking zone through the coking zone. to the other end thereof, the improvement which JEAN DELA'I'I'RE SEGUY.

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