US2087507A - Process of hydrocarbon oil conversion - Google Patents

Description

July 20,- 1937. c. P. DUBBS PROCESS OF HYDROCARBON OIL CONVERSION Original Filed Aug. 1, 1930 Z 7Z?/7%0T--' 4 66670072? c466:

Patented July 20, 1937 UNITED STATES ans? PROCESS OF HYDROGARBQN OIL CONVERSION Application August 1,

1930, Serial No. 472,233

Renewed September 20, 1935 2 Claims.

This application is a continuation in part of my co-pending application, Serial No. 453,594,

filed. May 19, 1930.

This invention relates to improvements in the art of converting high boiling hydrocarbons to lower boiling point hydrocarbons, and pertains in its specific embodiment to the treatment of heavy residual oil produced in cracking processes at elevated temperatures for the purpose of producing marketable fuel oils therefrom.

In most oil conversion processes and in most operations thereof, heavy residual oils are produced, the usual aim being to manufacture from any given charging stock a maximum yield of motor fuel and a minimum yield of heavy residual oil and coke. In producing a maximum yield of gasoline, the residual oil from the process is frequently so heavy and viscous that it is not suitable for marketing. My invention provides steps 20 or improvements in processes whereby residual oils are converted to salable fuel oil.

The extent of cracking, i. e. the yield of gasoline is usually limited to the point where coke begins to form in more or less substantial quantities, or to the point where the residual oil becomes too heavy and viscous to be' of commercial use. In the improved practice which constitutes my invention these processes are not so limited. A greater yield of gasoline can be produced and the residual oil from the operation can be treated so as to produce a desirable fuel oil.

In the cracking processes generally, the oil is heated as a body or in a single or number of streams. After this heated oil has undergone conversion a non-vaporized oil is separated from gases and motor fuel containing hydrocarbon vapors, before or after removal from the reaction zone. Non-vaporized oil in some operations is retained in the reaction or vaporizing zone for an extended period of time and in other operations is removed from the zone of reaction after shorter periods of time thereby avoiding undesired reactions. Whether this non-vaporized oil is cooled directly or subjected to conditions whereby lighter hydrocarbons are removed by vaporization, the final non-vaporized residual oil can be subjected to the process of my invention wherein this oil can be rendered into a more desired fuel oil product.

In applying my invention to the residual oil produced in one embodiment of the cracking process, the non-vaporized oil, either withdrawn from the reaction chamber or formed in .a subsequent stage of treatment, as for example where this oil is subjected to flash distillation at reduced pressure, or a mixture of such oils is processed in a heating element where it is treated at elevated temperature .and preferably at superatmospheric pressure. The conditions of processing are so selected as to reduce the viscosity of the oil treated to the degree necessary to meet market specifications. In the preferred embodiment of my invention, the non-vaporized residuum oil after being heated to a suitable temperature is rapidly cooled so that no further reaction in the oil takes place. Gasoline may be formed in the operation which can be separated from the processed oil so that it has proper test qualities as to flash and fire. The invention will be more readily understood by referring tothe accompanying drawing, which illustrates a diagrammatic side elevational View, not drawn to scale, of a cracking process in which my invention can be applied.

Referring to the drawing, the charging stock is directed to the process through line i and valve 2 to pump 3 which pumps the oil into line 4 from which a part or all of this oil may flow through line; 5, regulated by valve 6, to dephlegmator l where this oil is preheated by heat interchange with flash distillation vapors from flash distillation chamber 55. The pre-heated charging stock together with condensed vapors flow from dephlegmator 1 through line 8 and valve 9 to pump It which pumps this oil through line H and valve l2, in part or in whole, through line I3, regulated by valve i4, and through valve l5 into dephlegmator l6 where this oil is further heated by heat interchange with cracked vapors from reaction chamber 3!. The pro-heated oils, together with condensed, partially converted hydrocarbons, flow through line ll and valve I8 to pump l9 which pumps this oil through line 20 and valve 2| into line I I which leads into heating element 22 located in furnace 23.

When it is not desired to pump all or a part of the charging stock to dephlegmator l, as for example when its cooling effect is not desired, this oil may be directed from line 4 into line 24, regulated by valve 25, which leads through valve 26 into the products flowing to heating element 22 or through line 21, regulated by valve 28 into line 53 leading to dephlegmator Hi. The oil heated to suitable cracking conditions of temperature and pressure leaves heating element 22 through line 29, regulated by valve 3i! and flows to the reaction chamber 3! where cracking takes place and non-vaporized residue is separated from cracked vapor and gaseous products. Non- Vaporized residual oil is withdrawn through line 7 described above.

32, regulated by valve 33, and is subsequently processed as will be later described.

Vapors and gases leave reaction chamber 3| through line 34, regulated by valve 35 and flow to dephlegmator I6 where partially converted hydrocarbons are separatedfrommotorfuelcontaining hydrocarbons, the partially converted hydrocarbons condensing and mixing with the oil introduced through line I3 and being then directed to the heating element for treatment as has been- Motor fuel containing hydrocarbons leavedep-hlegmator I5 through line 36, regulated by valve 3! flowing to the condenser 38 and the cooled and condensed products thencefiow through line 39, regulated by valve. 49, to

'receiver 4| Where liquid and gaseous products are separated. Gaseous products are removed through line 42, regulated by valve 43, and liquid products are removed through line 44, regulated by valve 45. Any desired portion of the liquid in receiver 4| may be directed through line 46, regulated by'valve 41, to the pump 48 which pumps this oil through line 49 and vaive 59 to the top of dephlegmator I8 so as to control the temperature and thus regulate the quality of the overhead product. r

The non-vaporized residual oil removed from reaction chamber 3| through line 32, regulated by valve'33, may flow into line 52 and thence into line 53, regulated by valve 54 leading into fiash'distillation chamber 55 where this oil is treated 7 preferably at reduced pressure and flash distilled, untilizing its latent heat. Unvaporized oil is removed through line. 55, regulated by valve 51, and will be processed according to my invention as will be later described. Vapors and gases from flash distillation chamber 55 flow through line 58, regulated by valve 59 into dephlegm-ator I where they may be cooled by incoming charging stock introduced through line 5 and the condensed products directed through line 8 as previously described. Motor fuel containingvapors and gases leave dephlegmator' I through line 69, regulated by valve GI, and 'flow through condenser 62 and the cooled and condensed products thence flow through line 93, regulated by valve 94 into receiver 65 where liquid 7 and gaseousproducts are separated. Gaseous products are removed through line' 61, regulated by valve 68, and liquid products are removed through line 69, regulated by valve I0.

In the practice of my invention the unvaporized oil from flash distillation chamber removed through line 56, regulated by valve 51, is directed into line I I, regulated by valve 12, leading to pump I3 which pumps this oil through line 14, regulated by valve I5, into heating element I5 located in furnace II. The oil is here processed at suitable temperature and pressure conditions and the processed oil leaves the heating element through line I8 and may be directed into line I9, regulated ,by'valve 89, into the lower part of dephlegmator and separator 8| where motor fuel containing liquid and gaseous products are separated. Gases are removed through line 88, regulated by valve 89, and the liquid products are remowed through line 98, regulated by valve 9|.

Steam. or other suitable means may be injected into the non-vaporized oil or into zone 8|, as for example, through line I I5, regulated by valve II 6, to assist in removing light hydrocarbons so that the final fuel oil product will have the desired, flash and fire test. Non-vaporized oil from dephlegmator and separator 8| may be with drawn through line 92 and directed through line 93, regulated by valve 94, into line 95 leading to cooler 96 and the cooled oil leaving cooler 98 through line 91 directed to line 98, regulated by valve 99, and thence to. storage. Anny desired portion of the cooled oil leaving cooler 96 through line 91 may flow to valve I99 to pumpIOI which pumps this oil through line I02 and valve I03 into line I8, thus effecting cooling of the heated product leaving heating element I6. A portion of the non-vaporized residual oil withdrawn from reaction chamber 3| and flowing through line 52 may also be used inthis manner for cooling purposes by' allowing it to flow of its own pressure through line I84, regulated by valve I05, and thence intoline I02 leading to line I8, or the oil in line 52 may be directed into line II3, regulated by valve H4, and thence through line 9'Ito the suction side of pump. I91 which pumps the oil through line I82 into said line I8.

In the event that a coke-containing oil is ob- V tained in the lower part of zone 8|, a coke-com taining sludge may be removed, as for example through line 92 and valve I96 leading to a suitable disposal, valve 94 in line 93 being closed. The clean and substantially coke-free oil is then removed as for example th'rough line 95, regulated by valve I81. In some operations theheated products leaving heating element It through line I8 are preferably directed through valve IIII'into line 95 leading to cooler 95, thus avoiding processing in zone 8|.

Where it'is desired to process a portion of the non-vaporized oil' from reaction chamber 3| removed through line 32, directly in the heating pumped together with other products to heating 7 element I6.

. subjecting the non-vaporized oil from the reaction chamber 3| to treatment in the heating element I6 is particularly desirable when the operation of the process is so controlled that the chamber 3| is used as a combination reaction and flashing distillation chamber wherein the pressure is reduced as the'oil passes from the heating coil. 22 to the chamber 3| by obvious manipulation of the pressure control valve 39. In this modification of my process the chamber 55 and its connected parts may be dispensed with. In this operation it may be desirable to subject all of the residuum Withdrawn from the chamber 3| directly to the action of a treatment in the heating element I6.

7 It is to be understood that while my processiis being described more particularly with the use of so-called clean circulation, the features of my invention can be used to advantage with processes of the so-called cyclic circulation type, wherein oil is subjected to conversion by passing to and from an enlarged zone through a heating coil.

In the practice of my invention, temperatures may be used from 750 to 1000 F., more or less. The pressure may range from high superatmospheric pressure, for example, 2000 pounds per square inch or more, to sub-atmospheric or atmospheric pressure. These pressures may vary within the system, various pressures being used in the various elements comprising the process or substantially equalized pressures may be used.

Heavy oils issuing from conversion processes having viscosities as high as 12,000 seconds Furol, or more, can be treated to produce fuel oil of 200 to 300 seconds Furol viscosity or less having also suitable flash and fire test.

As a specific example of the application of my invention to a cracking process well known in the industry where a topped crude oil of 18-20 A. P. I. gravity is being processed, this oil is heated together with partially converted hydrocarbons from the process in heating element 22 so that the temperature at the outlet of this heating element may be approximately 915 F., and the pressure therein may be approximately 250 pounds to the square inch, and as the oil enters the chamber 3! the pressure may be reduced to, say pounds per square inch. The pressure on the dephlegmator I6, condenser 38 and receiver ll may be substantially equalized with the pressure in the chamber 3| and it is regulated by maintaining a level of the motor fuel containing distillate in receiver 4! and by releasing uncondensable gases through line 42, regulated by valve 43. The gasoline produced represents approximately 38-40 percent based on the 18-20 gravity oil charged to the process.

Non-vaporized oil from chamber 3!, which has a Furol viscosity of approximately 1000 at 122 F. is directed to heating element 16 according to the improvement comprising my invention and is heated to approximately 915 F. at a pressure of approximately 300 pounds per square inch. Oil withdrawn from zone BI and cooled in cooler 96, together with a small amount of oil withdrawn from reaction chamber 3|, is pumped into the heated products leaving heating element 16 before emerging into dephlegmator and separator 8i. The heated products are thereby cooled to approximately 600 F. and the pressure is reduced so that a pressure in zone 8! is approximately pounds per square inch. A small amount of gasoline containing hydrocarbons is removed at the top of zone 8|, the character of which is partially regulated by cooling with motor fuel containing distillate from receiver 4| introduced through line I08, regulated by valve I09.

The cooled final fuel oil product from this process has a Furol viscosity of approximately seconds and as a result of the improved practice in connection with the cracking operation yield of gasoline has been increased from approximately 4-6 percent based on the oil charged to the cracking process or approximately 10-15 percent based on the total gasoline output.

The above illustrations and examples should not be construed as limitations on the broad scope and spirit of the invention.

I claim as my invention:

1. A process for producing motor fuel and fuel oil which comprises heating hydrocarbon oil to cracking temperature under superatmospheri'c pressure while flowing in a restricted stream through a heating zone, subsequently discharging the heated oil, both vaporous and liquid, into an enlarged zone maintained under a materially lower pressure than the heating zone and separating vapors from unvaporized oil therein, fractionating and finally condensing said vapors and recovering the final distillate, increasing the pressure on the unvaporized oil to above that maintained on the oil in the heating zone and passing the same, without material positive cooling, to a second heating zone, heating the unvaporized oil under the increased pressure in said second Zone to a viscosity-reducing temperature not substantially in excess of that to which the oil is heated in the first-mentioned heating zone, removing the oil from the second heating zone and without vaporization cooling the same, introducing a portion of the cooled oil to the heated oil being removed from the second heating zone as a cooling agent therefor, and recovering the remaining portion of said cooled oil.

2. A process for converting hydrocarbon oil into gasoline-like products and a marketable fuel oil residue comprising initially subjecting the hydrocarbon oil in a heating zone to an active cracking temperature, thence passing the hydrocarbon oil to a reaction zone, passing liquid residual products from said reaction zone to a low pressure flash distillation zone, taking off unvaporized heavy residue from said low pressure flash distillation zone, passing the same thence through a second heating zone wherein it is raised to a cracking temperature to effect reduction in the viscosity of said heavy residual oil, cooling the efilux from said second heating zone without vaporization thereof and dividing the thus cooled oil into two portions, recovering one portion as a productof the process while utilizing the remaining portion as the cooling medium for the oil discharging from said second heating zone.

CARBON P. DUBBS.

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