US2294565A

US2294565A - Cracking hydrocarbon oil

Info

Publication number: US2294565A
Application number: US328166A
Authority: US
Inventors: Lemen William Edward
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1940-04-06
Filing date: 1940-04-06
Publication date: 1942-09-01
Anticipated expiration: 1959-09-01

Description

Sept. 1, 1942. w. E. LEMEN CRACKING HYDROCARBON OIL Filed April 6, 194C 4 II'and valve I2.

Patented Slept. 1y, 1942 UNITED STATE s PATENT oFFlcE CRACKING HYDROCARBON OIL William Edward Leinen, Chicago',

Universal Oil Products Company, Chicago,

IIL, assignorto Ill.,

a corporation oi Delaware l Application April 6, 1940, Serial No.v 328,166

4 Claims;

This invention 4relates to a process for converting hydrocarbon oils containing substantially noy gasoline into motor fuels of high antiknock value. More specically the process relates to an improved method for cracking petroleum oilsand similar charging stocks inthe presence ing catalyst, passing the higher and lower boiling v fractions to a reaction zone, removing vaporous products therefrom to a fractionating zone, passing liquid reaction products' containing catalyst in suspension to a vaporizing zone, passing the vaporous reaction products therefrom' to 'said fractionating zone, recovering the' spent catalyst from said vaporizing. zone, separating gasoline and gas Vfrom said fractionating z'one, mixing a higherboiling fraction of insuiiiciently converted oil with/powdered catalyst, heating the mixture and passing it to said reaction zone for further conversion as previously indicated, heating a lower boiling fraction in the absence of catalyst and. supplying it yfor conversion as previously mentioned.

The process is illustrated diagrammatically in the accompanying drawing which should not be interpreted as limiting it to the exact apparatus or conditions shown therein. The apparatus is I4. An Aintermediate boiling fraction is removed from the fractionatorthrough line I5, valve I6, pump Iland valve I8 to coil I9 which is disposed in 'heater a cracking temperature within the range of approximately 800-1200 F. and passed through line 2l and valve 22 to reaction chamber 24. A

l higher boiling fraction of oil is removedv from fractionator 6 through line 25, valve 26, pump 21 and valve 28 and is mixed with powdered cracking catalyst from catalyst charger 29, the catalyst entering through line 30, valve 3|, pump 32 and valve 33, joining with line 25. The catalyst may be suspended in a portion or all oi the charging r stock or in an intermediate boiling 'fraction of hydrocarbon oil. The mixture of the higher boiiing fraction of charging stock and catalyst passes through line 34 and valve. 35 to coil 36 which is disposed in heater 31. The mixture is heated to a cracking temperature and pressure, the temy perature being below that at whichv the crack- ,ing reaction becomes, excessively rapid, usually y within the range of approximately 500-1000 F.

and a pressure of approximately 50-1000 pounds per square inch. The additional heat required is supplied by the intermediate boiling fraction from line 2|.` TheI reaction mixture passes through line 38 and valve 39 and thence to reaction chamber 24. A liquid level may be maintained in the reaction chamberwhlch is operated 'at a temperature Within l. the t range ofv approximately 500-1000 F. `or higher andv a pressure of 10D-1000 pounds persquare inch. The maintenance of a liquid level in the reaction chamberr permits adeshown in side elevation and has not been drawn to scale, nor has any attempt been made to prof portionate the various parts of vthe equipment exactly. y l

A charging stock which may comprise crude oil or topped crude oil, but is preferably a distillate fraction of a crude hydrocarbon oil, is introduced through line I, valve 2, pump 3, valve 4 and line 5 to fractionator 6. If a crude oil containing substantial quantities of gasoline is used, the gaso- Y line, together with the cracked gasoline and gases produced as hereinafter described, is removed through line I,valve 8,-condenser 9 to receiver lofi-om which gases are removed to suitable absorption equipmentl not shown through-inne The gasoline may be removed quat contact of the hydrocarbon oill ,with the powdered catalyst. The reaction products are in- `troduced at a point below the surface of the liquid which prevents the catalyst `vfrom settling from the oil while in the chamber.

The particular advantage of this operation is that additional heat may be supplied tovthe reaction chamber by means of the light hydrocarbonfraction which is heated in coil I9.

Vapors from the reaction chamber are removed through line 40 and valve 4I to line 5 and thence to fractionator 6. The liquid portion of reactionv products containing catalyst in suspension is withdrawn through line 42 and valve 43-to vaporizingchamber ,44' which is maintained at a substantially lower pressure than reaction chamber 24. The major portion of the material is vato a stabilizer not shoyvnv through line I3 and valve 55 porized at this point and passedthrough line and valve 46 which joins with line 40 and is passed to the fractionator 6. As in the case of reaction chamber 24a liquid level may be maln- 20. This oil may be heated to tained in vaporizng chamber M in order to obtain additional beneilt of the catalyst and to prevent the catalyst from separating and plugging the lines. A portion or all of the heated low boiling fraction from line 2i may be passed vthrough line 23 and valve 23 to line 42 and valve B3 to supply additional heat and assisty in vaporizing the oil in chamber 44. Residue containing catalyst in suspension is removed through line 47 and valve 48 to catalyst recovery system not shown. from theoil by filtering or other suitable means, and reactivated by treatment with an oxygencontaining gas at a temperature Within the range of approximately 80G-1500 F.

Cracking catalysts suitable for use in the present operation may comprise the so-called silicaalumina, silica-zirconia, silica-alumina-zirconia type catalyst which may be or may not contain small quantities of boron oxide or other agents to improvethe catalytica activity thereof. Composites of this type are prepared` by the separate or simultaneous precipitation of the component parts followed by washing and drying under such conditions that alkali .metal ions are substan- The catalyst is separated tially removed. The catalyst is used in the form, i

of a nely divided powderpreferably approaching colloidal dimensions in order to obtain a high y' R degree of catalytic surface and t0 prevent an undue amount of settling at various points in the equipment.

Other cracking catalysts may be used such as e `naturally-occurring earths or naturally occurring earths which have been treated with acid or other chemicals to increase their catalytic activity.

Still another type of catalyst comprises relatively inert carriers such'as alumina, magnesia, titania, zinc oxide, etc., having deposited thereon relatively minor amounts of the oxides or suldes of molybdenum, chromium, vanadium, etc.A This type of catalyst may als'o be mixed in varying proportions with silica-alumina, silica-zirconia, etc., type of catalyst. J /v The catalytic agents mentioned present process are not necessarily equivalent in the'reactions they promote or in the yield of desirable products obtainable. Theyvary considerably in catalyticactivity and the optimum temperature and pressure conditions, for eachcatalyst is not necessarily the same. r

The following'example is given to illustrate the forvuse in the usefulness and practicability of the process, but j should not be construed as limiting it to the exact conditions or'catalysts lused therein. l

A,Pennsylvania' distillate boiling in the range lof approximately 40G-760 F. may be treated in themanner described in the foregoing speciilcation wherein a light oil side cutof approximately kerosene biling range is processed in the light oil coilv and the residual portion is mixed with,l

approximately 2% by weight of silica-alumina cracking catalyst powder for treatment in the heavy oil coil. 'I'he light oil fraction is, heated to a temperature of approximately 975 F. under a pressure of approximately 500 pounds per square inch. 'I'he heavy oil fraction is heatedto approximately 800 F. under a pressure 4of 200 A Pound);` per square inch. The reaction chamber'- is maintained at a temperature of' approximately v S50-875 Il'.l and a pressure of 175 pounds per square inch. Vaporous reaction products are removed to the fractionator and the liquid products containing catalyst in suspension are passed to the vaporizing chamber which is maintained at a pressure of approximately 50 pounds per square inch. A total yield of gasoline amounting to '12%'of the original charging stock may be obtained in this way. An additional quantity is obtainable by polymerization of the normally gaseous olens contained in the gases.

I claim as my invention:

1. A hydrocarbon oil .conversion process which comprises fractionating the charging oil together with cracked 'vapors'formed in the process in a fractionating zone, removing from said zone a relatively heavy cracking stock and a lighter cracking stock, commingling a powdered cracking catalyst with the heavy stock and heating the mixture to at least 500 F. in a heating zone, discharging the heated mixture into a reaction zone, thermally cracking said lighter stock in a. second heating zone at higher temperature than that to which said mixture is heated in the firstnamed heating ezone, discharging resultant heated products ln`to the reaction zone andtherein transferring heat from said products to said mixture, removing vapors from the reaction zone and supplying the same to the fractionating.

zone, and finally condensing the fractionated vapors. y l

2. A hydrocarbon oil conversion process which comprises fractionating the charging oil together with cracked vapors formed in the process in a fractionating zone, removing from said zone a relatively heavy cracking stock and a lighter cracking stock, commingling a powdered cracking catalyst with the heavy stock and heating the mixture to at least 500 F. in a heating zone,

vdischarging, the heated mixture into` a reaction finally condensing the fractionated vapors.

l 3. A hydrocarbon oil conversion process which comprises commingling a powdered cracking catalystr with a relatively heavy oil, introducing the resultant mixture to a reaction zone maintained under catalytic cracking conditions, simultaneously subjecting a lighter oil to thermal cracking at highertemperature than that maintained in the reaction zone, discharging resultant heated products into the reaction zone and therein transferring heat from said products to said mixture to supply heat for the catalytic crackingoi' said heavy oil, removing vapors from the reaction zone and fractionating and lcondensing the same, separately removing admixed unvaporized oil and catalyst from the reaction zone and introducing"` the same to'a reduced pressure vaporizing zone,- and discharging additional heated productsfromthe thermal cracking step into said vaporizing zone .to assist the vaporization of oil from catalyst therein.

4. Thev process as dened in claim 3 further characterized in that vapors evolved in the vaporizing zone are combined with the vapors from the reaction zone for fractionation andv condensation therewith. v