US1992512A - Process and apparatus for increasing the octane value of liquid hydrocarbon motor fuels - Google Patents

Description

Feb. 26, 1935. A. D. SMITH 1,992,512

PROCESS AND APPARATUS FOR INCREASING THE OCTANE VALUE OF LIQUID HYDROCARBON MOTOR FUELS- Filed Oct. 20, 1952 ARTHUR D. J'M/TH Patented Feb, 26, 1935 4 barrel states PROCESS AND APPARATUS FOR meanes- ING THE OCTANE VALUE 0F LIQUID HY- DROCARBON MOTOR-FUELS Arthur D. Smith, Chicago, m, assignor to Jenkins Petroleum Process Company, Chicago,

BL, a corporation of Q Application October 20,

8 iClairns.

This invention relates to a method and apparatus for increasing the so-called octane value of liquid hydrocarbon motor fuels, and particularly to a method and apparatus whereby a maximum yield of relatively light, anti-knock motor fuel, such as gasoline of high octane value, may be obtained from liquid hydrocarbons of lower octane value.

One object of the invention is to provide for the continuous production of gasoline of high octane rating, by commingling under pressure, in a constricted tubular means, a stream of cracking hydrocarbon vapor, comprising .high octane fractions, with a stream of substantially liquid hydrocarbons obtaining approximately at an incipient cracking temperature; followed by immediately diffusing the resultant, partially vaporous mixture in a body of combinative hydrocarbon vapor, comprising relatively low octane fractions, obtaining under cracking conditions of heat and pressure less than the cracking hydrocarbon vapor; maintaining the diffused, admixed vapor under such cracking conditions for a period formative of an increase in high octane fractions; and dephlegmating the vapor so treated to separate high octane gasoline.

Another object of the invention is to provide for the continuous production of high octane gasoline, by subjecting a stream of relatively light hydrocarbons, dephlegmated in a concurrently operated, cyclic cracking process, to cracking in vapor phase under a pressure and at a temperature best suited to produce high octane fractions; commingling such cracking vapor, in a constricted tubular means, with a stream of substantially liquid heavier hydrocarbons refluxed in the cyclic process and preheated therein to approximately an incipient cracking temperature; immediately diffusing the resultant, partially vaporous mixture in a body of combinative hydrocarbon vapor, comprising relatively low octane fractions, also produced in the cyclic process and obtaining under the therein cracking conditions of heat,and pressure; maintaining the thus 'difiused, admixed vapor under such cracking conditions, for a period formative of an increase in high octane fractions; and dephlegmating the vapor so treated to separate high octane gasoline.

An additional purpose of the invention includes inhibition of undesirable polymerization and/or decomposition of a stream of cracking hydrocarbonvapor, comprising high octane fractions; effected by rapidly cooling such stream by comminglement under pressure, in a constricted tubular means, with a stream of substantially liquid Wisconsin 1932, Serial No. 638,829

glement as above described; to effect such comminglement in a constricted tubular means, preferably of a conventional eductor type; to eject the commingled mixture therefrom as a confluent.

spray or mist, consisting of vapor saturated with minutely divided, liquid particles; to diffuse such saturated vapor, without an appreciable intervening interval, in a body of combinative hydrocarbon vapor, comprising low octane fractions, arising from a freely contacting pool of cracking liquid hydrocarbons; and to maintain the diffused, admixed vapor in contact with such pool, for a period formative and fixative of high octane fractions.

In order that the method and apparatus employed may be more clearly understood, reference ismade to the accompanying drawing, where Fig. 1 represents partly in vertical cross section, and partly in side elevation, one form of'means adapted for carrying out the invention; while Figs. 2 and 3 designate plan and end views respectively, of the eductor connections employed in said means.

The general apparatus includes a known type of still suitable for conducting a mixed phase cyclic cracking process, comprising an upper 1ongitudinal drum 1, superimposed over front and rear sluiceways 2 and 3, joined to upper and lower transverse drums 4 and 5; these latter being united by the tube bank 6, heated by furnace '7. Cyclic circulation of the still contents is effected by the propeller 8, located in rear sluiceway 3, and driven by motor 9 through the agency of shaft 10... From near the rear head of the upper longitudihal drum, a vapor line 11 freely connects to the baffle tower 12, from the base of whicha reflux line 13, including its internally extended, preheating nipples 13, is in uninterrupted connection with a constricted, confluent tubular means,preferably an eductor 14.

The latter, which is of the conventional, spray discharge type, is installed in theVfront end of the drum 1, in the vertical, axial plane thereof; with nozzle slightly above, and at an angle of about 15 to the plane of the operating level 15, so that the ejected spray will take approximately the outline 15'. The eductor is actuated by vapor entering through line 36.

Continuous charging of the cyclic cracking system is effected by the pressure pump 16, taking suction from a source of supply not shown; and discharging through line 17, as controlled by valve 18, to near the top of the reflux tower 12. Provision is also made for introduction of the regu lar charging stock, and/or other suitable heavier hydrocarbon through the reflux line 13, by means of a branch line 19. Pumps 16 and/or 16' are employed for such purpose, through proper adjustment of valves 18, 18 and 18"; the latter being installed on a line taking suction from a source (not shown) without the apparatus.

Withdrawal of the still contents is normally effected through the line 20, as controlled by valve 20'. The still is furtherprovided with the usual accessories such as safety valve, liquid level gauge, and instruments for indicating and/or recording pressure and temperature.

Pressure distillate is released through the line 21, as controlled by valve 22, to the bubble tower 23, from which'dephlegmated gasoline escapes through line 24, as controlled by valve 25, to a condensing means (not shown). The condensate in bubble tower 23, i. e., pressure distillate bottoms or relatively light hydrocarbons, flows through the line 26, to the accumulating drum 27, from which it may be withdrawn from the system through valve 28.

The pressure pump 29, with supply thereto controlled by valves 30 and 30, taking suction respectively from the accumulating drum 27, and a source (not shown) without the apparatus, discharges through stop valve 29' and line 31, to the cracking coil 32, located in the furnace 33; both coil and furnace being of conventional type and the latter heated by any suitable means.

Operating pressure in coil 32 is controlled by valves 34 and 35 installed in lines 36 and 36' respectively. Line 36 enters the drum 1 through the front head thereof, and connects to the before mentioned eductor 14. When the vapor released through valve 34 is under insuflicient pressure to actuate the eductor, the compressor 37, driven by any conventional means, is employed to develop the necessary force. In such instance the normally closed valve 35 would be opened, and the normally opened valve 34, would be closed.

In carrying out the invention, let it be assumed that a known type of continuous, cyclic process is in concurrent operation, wherein a body of cyclically circulating oil, containing a dispersed mineral adsorbent such as lime, is maintained in drum 1 at say a temperature of about 785 F. and under a pressure of about 135 lbs. that charging of the system is through line 17; that pressure distillate (crude gasoline) is produced; that reflux therefrom, together with fresh charging stock, (such composite forming one source of the before mentioned heavier hydrocarbons) preheated in its passage, but still substantially in liquid phase, flows from the bafile tower 12 throughline 13 and eductor 14 into drum 1;

that pressure distillate bottoms (forming one source of the before mentioned relatively light hydrocarbons) flows from bubble tower 23 through line 26 to the accumulating drum 27; that gasoline of say 63 octane rating is released through line 24; and that a sufficient quantity of the still contents is withdrawn through line 20 to maintain the operating level at 15.

When a sufiicient quantity of relatively light hydrocarbons has flowed into the accumulating drum 27, continuous charging therefrom is effected by pump 29 through line 31 to the coil 32, which is maintained at a temperature and under a pressure formative of high octane gasoline, such pressure usually obtaining in coil 32, that the therein treated product, as released through valve 34, will freely enter the eductor 14 in vapor form. The actual temperature and pressure employed will vary with the composition of the relatively light hydrocarbons processes. As the invention comprehends the substitution of the pressure distillate bottoms dephlegmated from the concurrently operated cyclic process, either Wholly or in part by distillate, naphtha and gasoline of low octane rating, or composite fractions thereof, (taking suction through valve 30' from a source without the appartaus); no definite temperature limits can be set, but generally a range of 900-1200 F. will suflice to secure the desired intermediate octane increase. Where insufficient pressure is developed, by reason of the obtaining temperature, recourse is had to the compressor 37, in the manner before described.

Upon comminglement of the stream of cracking vapor with the cooler stream of heavier hydrocarbons, an eductive effect is produced on the reflux flow, preventive of gas-locking and/or accumulation and subsequent sudden release of baffie tower condensate, so harmful and dangerous to regular operation; this insurance of regular flow being especially beneficial where solid adsorptive material is mixed with the reflux flow.

Undesirable polymerization and/or decomposition of the cracking vapor entering the eductor 14 is prevented in two distinct, inhibitive stages; 1. e., initially, through reduction of the temperature of such vapor through comminglement with the stream of heavier hydrocarbons to a point somewhat above the obtaining cracking temperature of the cyclic process; employing where necessary to effect the requisite degree of cooling, additional heavier hydrocarbons over the normal, composite reflux, by diverting a portion of the main charging stock through the branch line 19; or replacing such increase, wholly or in part, by heavier hydrocarbons from without the system, such as crude, distillate and/or natural gasoline, introduced by pump 16' in a manner previously described. The second stage of inhibition occurs through reduction in the temperature of the partially vaporous mixture, resulting from comminglement as above described, upon diffusion of such mixture in the pressure distillate vapor of the cyclic process; such stage following the first with an intervening period so infinitesimally small as to be in effect concurrent therewith, and in the total temperature reduction thus preventive of undesirable polymerization, but permitting that of gum forming compounds.

It will be noted that under the immediately above described conditions, the cracking vapor entering the eductor 14, first commingles with relatively unthermalized hydrocarbons; secondly, the resultant," partially vaporous mixture then diffuses in the more thermalizd vapor of the cyclic process; and thirdly, the thus difiused vapors remain in contact with the relatively highly thermalized, cyclically circulating, liquid body of hydrocarbons, until release from the cracking zone. Whether it be by reason of the cracking vapor first commingling with relatively unthermalized hydrocarbons, arid the product thereof diffusing in the more 'thermalized vapor of the cyclic process without a sufl'icient, interveninginterval of molecular rearrangement; or whether such rearrangement occurs upon initial contact, followed by metastatic change after diifusion; is not known.' The fact remains, that a higher octane gasoline is produced by the above treatment, than if the cracking vapor be directly cominingled with the more thermalized, cyclically circulating, liquid body; or the pressure distillate vapor derived therefrom.

The process possesses a further advantage, in that the diffused, combinative vapors obtaining as above described, must travel a relatively long path in contact with the cyclically circulating, liquid body before release from the cracking zone, such interval being productive of fixation of high octane gasoline; so that the flnalvapor, after refluxing and dephlegmation in baflie and bubble towers l2 and 23, respectively, yields uponcondensation a gasoline of octane value otherwise unobtainable; in short in the vicinity of 10 to 15 points increase in rating, depending on the nature of the original stock processed.

The invention is not limited to the apparatus, nor to the combination with the specific cyclic process herein described; nor to the temperatures, pressures and exact types of hydrocarbons herein mentioned by way of example; and what I claim is new and desire to protect by'Letters Patent is:

1. Process for the production of gasoline of high octane rating which comprisescornmingling under pressure in a constricted tubular means a stream of relatively light hydrocarbon containing fractions of high octane rating and obtaining under vapor phase cracking conditions with a stream of substantially liquid hydrocarbon obtaining approximately at an incipient cracking temperature, substantially concurrent with such comminglement eflecting fractional vaporization and diflusion of the resultant hydrocarbon composite within a body of hydrocarbon vapor nascently generated from a freely contacting pool of cyclically circulating, relatively heavy hydrocarbon obtaining under cracking conditions of heat and pressure less than said cracking hydrocarbon vapor, maintaining the diffused admixed vapor substantially under the cracking conditions of said relatively heavy hydrocarbon for a period formative of an increase in gasoline of high octane rating and subsequently dephlegmating the vapor so treated to separate said gasoline of high octane rating.

2. Process for the production of gasoline of high octane rating which comprises commingling under pressure in a constricted eductive means a stream of cracking hydrocarbon vapor containing high octane fractions with a stream of substantially liquid hydrocarbon obtaining approximately at an incipient cracking temperature,-

subtsantially concurrently with such comminglement vaporizing light fractions of said liquid hydrocarbon, condensing heavy fractions of said hydrocarbon vapor, ejecting and diffusing the resultant hydrocarbon composite as a confluent spray or mist within a body of hydrocarbon vapor comprising fractions of, relatively low octane rating nascently generated by a freely contacting pool of cyclically circulating, relatively heavy hydrocarbon obtaining under cracking conditions of heat and pressure less than saidcracking hydrocarbon vapor, maintaining the diffused admixed vapor substantially tinder the cracking conditions of said relatively heavy hydrocarbon for a period formative of an increase in gasoline of high 00- process to cracking in vapor phase under a pres- I sure and at a temperature best suited to produce gasoline of high octane rating, commingling suchcracking vapor in a confluent eductive means with a stream of substantially liquid heavy hydrocarbon refluxed in said cyclic cracking process and preheated therein to an approximately incipient cracking temperature, substantially concurrently with such comminglement ejecting from said eductive means the resultant hydrocarbon composite as a confluent mist or spray consisting of vapor saturated with minutely divided liquid particles and diffusing said spray within a body of hydrocarbon vapor comprising fractions of relatively low octane rating nascently generated from a freely contacting pool of cyclically circulating, relatively heavy hydrocarbon obtaining under cracking conditions of heat and pressure less than said cracking hydrocarbon vapor, maintaining the, difiused admixed vapor substantially ing fractions of high octane rating to a degree preventive of undesirable polymerization, efiected in the first stage by reducing the temperature of said stream to a degree inhibitive of said undesirable polymerization but less than finally desired through comminglement in a confluent eductive meanswith a stream of substantially liquid hydrocarbon, and in thesecond stage by reducing such intermediate temperature to a final preventive degree by expanding and diflusing the resultant hydrocarbon composite of such comminglement as a confluent spray or mist within "a body of hydrocarbon vapor nascently generated from a freely contacting pool of cyclically circulating, relatively heavy hydrocarbon obtaining at substantially said preventive temperature.

5. Process for the continuous production of gasoline of high octane rating which includes the steps of subjecting a stream of relativelylight hydrocarbon dephlegmated in a concurrently operated cyclic process, or extraneously supplied, to cracking in vapor phase under a pressure and temperature best suited to produce fractions of high octane rating, conducting such cracking vapor to a confluent eductive means locatedwithin a conversion drum and arranged to discharge in the normal vapor space thereof, conveying to said eductive means through a separate tubular means disposed within said conversion drum a stream of relatively unthermalized, substantially liquid hydrocarbon refluxed in said cyclic process or extraneously supplied, preheating said stream. to approximately an incipient cracking temperature, commingling said streams of cracking vapor and liquid hydrocarbon within said eductive means and substantially concurrently with such comprising fractions of relatively low octane ratcomminglement ejecting, expanding, contacting, and diffusing the resultant hydrocarbon composite as a spray or mist within a body of hydrocarbon vapor comprising fractions of relatively low octane rating nascently generated from a freely contacting pool of cyclically circulating, relatively heavy hydrocarbon obtaining under cracking conditions of said cyclic process, maintaining the difiused admixed vapor in contact with said pool for a period formative of an increase in gasoline fractions of high octane rating, withdrawing vapor so treated from said cracking conditions, dephlegmating said vapor and separating gasoline of high octane rating.

6. Cyclic process for the continuous production of gasoline of high octane rating which includes the steps of cyclically circulating relatively heavy hydrocarbon oil under cracking conditions of heat and pressure through a heating tube bank and a superimposed connecting conversion drum, conducting vapor evolved in said drum to a reflux tower, condensing in said tower heavier fractions of said vapor, conveying such condensed fractions or similar fractions extraneously supplied to a confluent eductive means disposed within said drum and arranged to discharge into the normal vapor space thereof, effecting such conveyance by a closed path within said drum separate from that of the evolved vapor conducted to said tower, releasing lighter fractions from said tower to a bubble tower, condensing and separating in said bubble tower heavier fractions of said lighter fractions as relatively light hydrocarbon, releasing the lightest fractions of said lighter fractions for subsequent condensation as gasoline, subjecting the relatively light hydrodephlegmated in said bubble tower or similar hydrocarbon extraneously supp'ied to cracking in vapor phase under conditions of heat and pressure best suited to produce fractions of high octane rating, conducting such cracking vapor to said eductive means for comminglement therein with said heavier fractions condensed in said reflux tower or similar fractions extraneously supplied, substantially concurrently with such comminglement ejecting, expanding, contacting, and diffusing the resultant hydrocarbon composite as a spray or mist in a body of hydrocarbon vapor ing nascently generated from a freely contacting pool of said cyclically circulating, relatively heavy hydrocarbon obtaining in said conversion drum under cracking conditions of said cyclic process, maintaining the diffused admixed vapor in contact with said pool for a period formative of an increase in gasoline fractions of high octane rating, withdrawing vapor so treated from said cracking conditions, dephlegmating said vapor and separating gasoline of high octane rating.

'7. In an oil cracking apparatus comprising a conversion drum, means for circulating cracking oil within said drum, a vapor line leading from said drum to a reflux tower, a reflux conduit from the base of said tower extending to and through the length of said drum to a confluent eductive means disposed in said drum and arranged to discharge in the vapor zone thereof, auxiliary charging means for supplying oil to said reflux conduit, cracking coil means, means for controlling pressure within said coil, a vapor conduit for conveying vapor from said coil to said eductive means, and mechanical means in said vapor conduit for producing pressure therein.

8. In an oil cracking still comprising a con-' version drum cyclically connected to a bank of heating tubes, a vapor line leading from said drum to a reflux tower, a reflux conduit from the base of said tower extending within and through the length of said drum to a confluent eductive means disposed therein and adapted to discharge in the normally vapor space of said drum, charging means for supplyingsaid tower and said reflux conduit with cracking stock, auxiliary charging means for supplying said reflux conduit, a vapor line leading from said reflux tower to a bubble tower, a vapor line leading from said bubble tower to a condensing means, a reflux conduit from the base of said bubble tower extending to an accumulating tank, a cracking coil, charging means for supplying said coil from said accumulating tank or other extraneous source, means for controlling pressure within said coil, a vapor conduit for conveying vapor from said coil to said eductive means, and mechanical means in said vapor pipe for producing pressure therein.

ARTHUR D. SMITH.

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