US1948736A - Hydrogenation system - Google Patents

Description

Patented Feb. 27, 1934v 1,948,! 36 HYDROGENATION SYSTEM Robert F. Ruthrufl, Hammond, Ind., assignor tov Standard Oil Company (Indiana), Chicago, Ill., a corporation of Indiana Application May 30, 1930. Serial No. 457,6l2

1 Claim. (01. 196-53).

This invention relates to a system for increas ing the hydrogen-carbon ratio of petroleum oils or byproducts and it pertains more particularly to the formation of gasoline from heavy high car bon oils or residues.

The object of this invention is to provide a a system wherein non-hydrogenatable carbon and/or diflicultly hydrogenatable carbons are removed from the charging stock and to thereby avoid carbon deposition in the system. A further object is to utilize more efiectively the hydrogenatable fractions of the oil, to reduce the amount of hydrogen necessary for the treatment,.

and to produce a generally more economical processand apparatus than has heretofore been available. A further object is to provide an improved combination of cracking equipment with hydrogenation equipment whereby the separate systems co-act in a new and novel manner. Other objects will be apparent as the detailed descrip-,

tion of my invention proceeds.

The process as applied to high carbon reduced crude maybe briefly described as charging stock is preheated to 900-925 Rand charged into coking drums wherein a considerable amount of cracking takes place, the gasoline and hydrogenatable products being discharged into a fractionating tower and the difiicultly hydrogenatable coke being withdrawn at intervals from the drums. The liquids from the fractionating tower which are heavier than gasoline are subjected to a pressure of 2000 or with hydrogen, heated to about 850 F. and passed over 'a catalyst, which may be a mixture of chromium and molybdenumoxides.

The products leaving the catalyst chamber are reduced to a pressure of about 300 pounds, flashed and fractionated, the high boiling point liquids being pumped through a chamber at a pressure of about 300 pounds and the low boiling point gases being removed, as hereinafter described. The products from the cracking chamber are introduced into a separator, liquids being withdrawn from the base thereof and introduced into one of the aforesaid preheaters, and gases and vapors being introduced near the base of a fractionating tower to strip the gasoline from the products leaving the catalyst chamber. The gas and vapors leaving the fractionating tower are cooled, the "gasoline is removed therefrom, and the hydrogen is separated from the hydrocarbon and other'gases, said hydrogen beingreintroduced into the system.

The invention will be more clearly understood from the detailed description as follows:

follows: The

3000 pounds, mixed preheater to a cracking In the accompanying drawing I have diagrammatically illustrated a system for carrying out my improved process.

The charging stock may be any hydrocarbon liquid which has a tendency to deposit coke. Eight percent reduced Mid-Continent crude (resulting from the distillation of 92% thereof) may be taken as an example. I may-also use reduced pressure tar, acid tar, or any other oil having a high carbon to hydrogen ratio.

The charging stock is introduced by pipes 10 into the coils ll of preheaterlZ from which the oil is discharged through manifold 13 and pipes 14, 15 and/or 16 into coking drum 1'? at a temperature of about'900 to 950 F. The liquid in the coking drums is maintained at cracking temperature by the constant inflow of hot liquid from the preheater and the reaction yields coke and light hydrocarbon oils. The coke is allowed to settle out or accumulate in the coking drums, and at intervals one of said drums is disconnected from the system and the coke is removed therefrom while the cracking reaction continues in i to separatortank 2'7, gasoline being withdrawn through pipe 28 and the non-condensible hydrocarbon vapors being discharged through pipes 29 and 30. i 1

The liquid hydrocarbons heavier than gasoline are withdrawn from the base of fractionating tower 22 through pipe 31, they are subjected to a pressure of about 3000 pounds by liquid pump 32 and are then passed through preheater 33 and pipe 34 to catalyst chamber 35. Hydrogen from high pressure main 36 is introduced into the oil by pipe 37 preferably before the oil enters the preheater, and this mixture of oil and hydrogen is heated to a temperature of about 800 to 900 F. and passed through catalyst chamber 35, the oil being either in the gaseous or linuid state. The catalyst is preferably a mixture of metals and/or oxides of metals of the sixth periodic group, an example of which is nine parts chromium oxide mixed with one part molybdenum oxide.

Should heavy tarry liquids accumulate in the base of the catalyst chamber, they may be withdrawn through pipe 38 and reducing valve 39.

The reaction products from the catalyst chamber are conducted by pipe 40 through reducing valve 41 into fractionating tower 42, which is equipped with suitable bubble plates and reflux means. Gases and vapors are removed from the top of this tower and liquids heavier than gasoline (of higher boiling point) are withdrawn through pipe 43, subjected to a pressure of about 300 pounds by pump 44, heated in preheater 45 to a temperature of about 900 F. and conducted by pipe 46 to cracking chamber or soaking drum 47. This drum may be of the type generally employed in cracking reactions, and it is, in effect, an enlarged conduit for holding the oils at cracking temperature for the desired time interval.

The mixture is withdrawn from the top of the cracking chamber by pipe 48 and introduced at an intermediate point into separator 49, which may be equipped with suitable bailles, bubble plates, reflux means, etc.

The liquid leaving the base of separator 49 may be withdrawn through pipe 51, valve 52, and pipe 53 to the charging stock entering preheater 12, or it may be withdrawn through pipe 51, valve 54 and pipe 55 to the charging stock entering preheater 33. The liquid in the base of separator 49 may be stripped with steam or with an inert gas, introduced through pipe 56.

The overhead from separator 49 is conducted by pipe 57 to a point near the base of fractionating tower 42, where it is used to strip the gases from the reaction products leaving catalyst chamber 33. The gases and vapors are removed from tower 42 through pipe 58, cooling coils 59, and pipe 60 into separator 61. Gasoline is removed from the baseof this separator through pipe 62 and reducing valve 63.

The gases and vapors leaving the top of separator 61 are conducted by pipe 64 to the base of scrubber tower 65, where they are scrubbed with a suitable liquid, such as absorbtive oil. The scrubbing liquid is withdrawn from the base of the tower through pipe 66 and reducing valve 67 into gas release chamber 68. The liquid is circulated from this chamber through pipes 69, pump 70, pipe 71 and nozzle 72 back into the scrubber for removing further amounts of hydrogen sulfide, metnane, and other gaseous impurities.

The purified hydrogen leaves the scrubber through pipe 73, is compressed to about 200 atmospheres in compressor 74, and is conducted by pipe 75 to pipe 36 where it is mixed with makeup hydrogen from the high pressure main 36.

The hydrocarbon vapors leaving release tank 68 are conducted through pipe 76 to pipe 30 where they are mixed with gases leaving separator tank From the above description it will be seen that I have provided a novel and efllcient combination I of coking, cracking and hydrogenation systems. Many of the gases and liquids resulting from one of these systems may be utilized by another of said systems without loss or heat or lowering of pressure.

The operation of the invention may be briefly summarized as follows: Petroleum oils having a high carbon to hydrogen ratio are heated in preheater A to coking temperature (about 900 F.) and are allowed to coke in suitable drums, B, C, and/or D. The overhead from these drums is fractionated'in tower E, thev gasoline fraction being condensed and removed therefrom in separator F. Heavy liquid from'fractionating tower E is subjected to about 200 atmospheres pressure, mixed with hydrogen, heated to about 850 F. in preheater G and contacted with a catalyst in chamber H. The hydrogenation reaction products are fractionated in tower J, the heavy fractions being pumped through preheater K into a cracking drum or reaction chamber L. Cracked gases from this chamber are separated in tower M and are used for stripping the liquid in the base of tower J. The vapors leaving the fractionating tower J are cooled and gasoline is separated therefrom in separator N, hydrogen being recov ered from the remaining gases in scrubber O and the gases and impurities being released from tank P. 1

While I have described in detail a preferred embodiment of my invention it will be understood that I do not limit myself to these details except as defined by the following claim.

I claim:

In apparatus for converting heavy hydrocarbons into gasoline, a coking system including means for heating oil to cracking temperature at relatively low pressures, and means for separating gasoline and coke from the remaining reaction products thereof; means for compressing said remaining liquid reaction products to pressures upwards of 100 atmospheres, and means for heating said compressed products to temperatures upwards of 750 F., meansfor contacting the same with hydrogen at said temperature and pressure, and means for separating gasoline and hydrocarbons lighter than gasoline from the hydrogenation reaction products; means for cracking the remaining hydrogenation products at a pressure of about 200 pounds, means for contacting the cracked vapors with the hydrogenated products and means for returning the cracked residues to a prior stage of the system.

ROBERT F. RUTHRUFF.

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