US2002729A - Process of producing motor fuels from hydrocarbon oils - Google Patents

Description

' May 28, 1935. M, C APPEL L 2,002,729

PRQCESS OF PRODUCING MOTOR FUELS FROM HYDROCARBON OILS Filed May 28, 1954 INVENTOR Hedfer Patented May 28, 1935 UNITED STATES PROCESS OF PRODUCING MOTOR FUELS FROM HYDROCARBON OILS Marvin L. Chappell, Watson, Calif.

Application May 28, 1934, Serial No. 727,972

8 Claims.

This invention relates to an improved method of processing hydrocarbon oils, such as naphtha, lamp oil distillates, gas oil stock, or other petroleum oil stocks, to produce by partial dehydrogenation, cracking and reforming, a motor fuel with high anti-detonating characteristics, and one which may be mixed or blended with other gasoline stocks to improve the anti-detonating characteristics thereof, and/or to produce a motor fuel with high anti-detonating characteristics and a marketable fuel oil from petroleum oil residuums or fuel oil stocks.

This application is in part a continuation of my pending application Serial No. 611,789, filed May 17, 1932, now U. S. Patent 1,984,519, for Process of producing motor fuel from hydrocarbon oils.

Briefly stated, my invention comprises passing hydrocarbon oil through a heating zone under superatmospheric pressure and heating the oil to a cracking temperature; passing the heated oil from the heating zone, with or without reduction of pressure, into a vaporizing zone and vaporizing the oil or a regulated portion thereof; continuously separating and removing the unvaporized oil from the vaporizing zone to produce a marketable fuel oil; mixing the vaporized portion of the oil in the upper section of the vaporizing zone with an aeriform fluid containing free oxygen of less concentration than atmospheric air, preferably ranging from 5 to approximately 18 per cent by volume free oxygen, in quantities suflicient to reduce the hydrogen content of the oil to preferably approximately 14.3 per cent by weight and to not less than 9 per cent by weight; passing the mixture of vaporized oil and aeriform fluid from the upper section of the vaporizing zone into a reaction zone and producing, by further cracking and reforming, oils of the carbocyclic series, such as mixtures of hexahydrobenzol, hexahydrotoluol, I hexahydroxylol, benzol, toluol, xylol, etc., which are oils having antidetonating characteristics when used as a motor fuel; continuously passing the dehydrogenated, cracked, reformed oils and aeriform products, as

produced, from the reaction zone into a fractionating zone, and separating, by fractionation, aeriform products, a motor fuel and a higher boiling distillate from a residual oil, and continuously returning the higher boiling oil, separated from the other fractionated products, to an upper section of the reaction zone to be further cracked for the further continuous production of motor fuel.

Processes of producing oils such as benzol, toluol, xylol, etc., by a partial combustion or dehydrogenation of hydrocarbon oils with air or in the presence of air at elevated temperatures, are known in the art, such as described in U. S. Patents 1,214,204 and 1,257,906, granted to Frederick W. Mann and Marvin L. Chappell, dated January 5 30, 1917 and February 26, 1918 respectively, in which aromatic bodies and gas are produced by passing hydrocarbon oil and air through a highly heated zone filled with contact material, at a pressure less than atmospheric. Similar processes 10 are also known for the production of motor fuel by a partial'combustionof hydrocarbon oil with air at elevated temperatures, under atmospheric or superatmospheric pressure. By such processes,

however, high losses are sustained due to the intensity of the oxidizing reaction or partial combustion of the 011 being processed, resulting in excessive formation of carbon and gas, which may be as much as 40-50 per cent of the hydrocarbon oil.

Now, I have discovered that these excessive losses due to the partial conversion of the hydrocarbon oil into carbon and gases by known processes employing air, are principally due to the aeriform fluid containing too high an oxygen concentration; that by the employment of an aeriform fluid containing free oxygen of lessconcentration than atmospheric air, preferably approximately less than 18 per cent by volume free oxygen, the time of the oxidizing reaction may be prolonged and modified toprevent to a high extent violent molecular disruption of the oil, and thereby decrease the formation of carbon and gaseous products, and that a higher boiling distillate may be separated from the reaction products and further cracked to increase the yield of motor fuel with high anti-detonating characteristics.

By this invention, an aeriform fluid having a free oxygen content of less concentration than atmospheric air, preferably ranging from approximately 5 to 18 per cent by volume, is introduced with hot oil vapor into a contact reaction chamber, at areaction temperature preferably ranging from approximately 800 to 1300 F., in quantities sufllcient to reduce the hydrogen content of the oil vapor to preferably approximately 14.3 per cent by weight and to not less than 9 per cent by weight, the extent of dehydrogenation depending upon the hydrogen content of the oil treated and the products desired.

For example, if it is desired to produce a motor fuel having an anti-knock value or octane number of say 73 to 80, an aeriform fluid having a free oxygen content of say 10 per cent by volume would be introduced in quantities sufiicient to reduce the hydrogen content of the oil to approximately 13 to 14.3 per cent, and a temperature would be maintained in the reaction chamber ranging from approximately 800 to 1100 F. If a motor fuel is desired having an "octane number of say to 90, the quantity of aeriform fluid introduced, having a free oxygen concentration of say 10 per cent, would be sufficient to reduce the hydrogen content of the oil to approximately 9 to 13'per cent, and the temperature maintained in the reaction chamber would be from approximately 1100 to 1300 F.

The aeriform fluid employed may be air diluted with products of combustion, nitrogen, carbondioxide, carbon-monoxide, or other like gases, and the oxygen concentration is varied depending upon the percentage of hydrogen contained by the oil being processed and the products desired. For example, if the oil to be processed has an average hydrogen content of say 16 per cent by weight, the oxygen concentration of the aeriform fluid would be maintained at preferably approximately 17 per cent by volume, and for an oil having a hydrogen content of 14 to 15 per cent, an oxygen concentration of preferably approximately 10 per cent by volume would be used.

An object of the invention is to produce a motor fuel suitable for use in internal combustion engines with a high compression ratio, without requiring the use of anti-knock compounds such as tetraethyl lead.

Another object of the invention is to provide a continuous system for producing motor fuel with high anti-detonating characteristics, and

, then utilizing the motor fuel produced to blend with other gasoline or motor fuel stocks lower in anti-knock value to improve the anti-detonating characteristics thereof.

Another object of the invention is to provide a process which may be regulated to produce a marketable fuel oil and a motor fuel of variable range in anti-knock values with maximum yields, from crude petroleum oil or petroleum oil residua.

Various other objects and advantages of the present invention will be apparent from the description of the preferred form or example of the process embodying the present invention. For this purpose reference is made to the accompanying drawing, in which there is illustrated a form of apparatus in which the invention may be performed. The drawing represents a diagrammatical view of apparatus in which the parts are in sectional elevation.

In the drawing, 3 represents generally a tank for holding the hydrocarbon oil to 'be processed. Pipe l, controlled by valve 2, connects tank 3 to a source of the hydrocarbon oil supply. Pipe 4, controlled by valve 5, connects tank 3 near the bottom to the suction side of pump 6. Pipe I connects the discharge side of pump 6 to heat exchanger 8. Pipe 9 connects heat exchanger 8 to heater coil II. Heater coil II is stationed in the upper section of heater or furnace I8. Heater or furnace I0 is provided with an oil or gas burner I2.

Pipe I3, controlled by valve I4, connects heater coil II to reaction chamber I5. The upper section of reaction chamber I5 is shown filled with contact material I8, such as checker brick work or hollow tile, supported by arch II, although an, open reaction chamber without contact material may be employed. Reaction chamber I5 is preferably lined with a fire resisting material, as shown by the numeral I8, which may be fire brick, fire resistant cement, or other suitable furnace lining known in the art.

Pipe I9 connects reaction chamber I5 at the top to heat exchanger 8. Pipe 20, controlled by valve 2|, connects heat exchanger 8 to fractionating tower 22. Fractionating tower 22 is provided with bubble trays 23 and a separator plate 62. Pipe 25, controlled by valve 24, connects fractionating tower 22 at thebottom to residuum tank 26. Pipe 21, controlled by valve 28, connects residuum tank 26 at the bottom to a fuel oil storage not shown. Pipe 64, with a U bend gas trap 63, connects fractionating tower 22 just above separator plate 62 to the suction side of pump 66. The flow of oil through pipe 64 is controlled by valve 65. Pipe 68, controlled by valve 61, connects the discharge side of pump 66 to an upper section of reactionv chamber I5. Pipe II, controlled by valve I0, connects reaction chamber I5 at the bottom to pipe 25.

Pipe 29 connects fractionating tower 22 at the top to condenser coil 3|. Condenser coil 3| is stationed in condenser box 30. Pipe 32 connects condenser coil 3| to gas separator 33. Pipe 34, controlled by valve 35, connects gas separator 33 to a gas storage tank not shown. Pipe 36 connects gas separator 33 to a gasoline or motor fuel storage tank 31. Pipe 38, controlled by valve 39, connects gasoline storage tank 31 at the bottom to a storage not shown.

Pipe 40 is connected to fiues 52 and 53. Pipe 4 I, controlled by valve 42, connects pipe 40 to the inlet of pump 45. Pipe 43, controlled by valve 44, connects pipe 4| to a source of atmospheric air, also to a source of nitrogen gas, carbondioxide or carbon-monoxide, through branch pipe 60, controlled by valve 6|. Pipe 46 connects the discharge side of pump 45 to heater coil 48.

Heater coil 48 is stationed in the upper section of heater or furnace 41. Heater or furnace 41 is provided with an oil or gas burner 49. Pipe 50, controlled by valve 5|, connects heater coil 48 to the lower section of reaction chamber I5.

The preferred process as carried out in the apparatus just described is'as follows:

Hydrocarbon oil, such as naphtha, lamp oil distillates, gas oil stock, petroleum oil residuum, or crude petroleum oil, contained in tank 3, is caused to flow through pipe 4and into the suction side of pump 6, the rate of flow being governed by operation of valve 5. Pump 6 discharges the hydrocarbon oil to be processed in a regulated stream flow, under a pressure which may range from approximately 50 pounds to as high as 1000 pounds gauge or higher, through pipe 1, heat exchanger 8, pipe 9, heater coil II, pipe I3, and into the vaporizing section of reaction chamber l5, wherein a residual oil is separated from the vaporized portion. The pressure maintained on the uil passing through heater coil I I is controlled by pressure regulating valves I4 and 2 I. The residual oil which collects in the lower section of chamber I5 is continuously or intermittently withdrawn into residuum tank 26 through pipes II and 25, controlled by valve I0. The oil passing through heater coil II is heated to an oxidizing reaction temperature, that is, to a temperature where rapid oxidation may be effected without molecular disruption when the vaporized portion is mixed with an aerii'orm fluid containing pref- .erably from approximately 5 to 18 per cent by volume free oxygen. The temperature employed to heat the oil being processed preferably ranges from approximately 800 to 1300 F., depending upon the stock treated and products desired, al-

though higher temperatures may be employed when high velocities are maintained.

The pressure on the heated oil stream may be reduced to approximately 50 to 300 pounds more or less, as it passes through pressure regulating valve I4, the exact reduction in pressure depending upon the boiling range of the oil and the temperature to which it is heated. For oils with relatively high boiling ranges, such as petroleum oil residua or gas oil distillate, a pressure of 50 to 100 pounds gauge more or less may be maintained in heater coil II, as well as in reaction chamber I5, controlled by valve 2I, while a pressure of 100 to 300 pounds or more may be employed in reaction chamber l5 when certain grades of lamp oil distillate or naphtha are being processed to increase the anti-detonating characteristics thereof.

In the vaporizing section of reaction chamber I5 the vaporized oil is mixed with an aeriform fluid containing, as heretofore stated, preferably from approximately 5 to 18 per cent by volume free oxygen, which has been preferably heated to a temperature ranging from 800 to 1300 F., and in quantities suflicient to reduce the hydrogen content of the oil to preferably approximately 14.3 per cent by weight and, to not less than 9 per cent by weight. The volume of aeriform fluid employed varies through a wide range, depending upon the grade and chemical composition of the oil to be processed.

For example, certain naphtha stocks derived from paraflln base crude petroleum oil, consisting principally of hydrocarbons of the paraffin series (CnH2n-1-2), may require as much as 300 cubic feet of the aeriform fluid (calculated at 0 C. and 760 mm. pressure) containing, say, 17 per cent by volume oxygen per gallon of stock, to produce a motor fuel or gasoline stock having an octane" number of 80 to 90. For certain distillates derived from an asphalt base crude petroleum oil, as little as 10 cubic feet of the aeriform fluid, containing from approximately 5 to 18 per cent by volume oxygen per gallon of stock, may be used to produce a motor fuel or gasoline stock with an octane" number ranging from '70 to 90.

Aeriform fluid or products of combustion from furnaces I0 and 41, containing from approximately 5 to 18 per cent by volume oxygen, are caused to pass from the flues 52 and 53 into pipe 40. From pipe 40 the flue gases pass through pipe M and then into the inlet side of pump 45, the rate of flow being regulated by operation of valve 42. By means of pipe 43 and branch pipe 50, controlled by valve 44 and valve GI respectively, the oxygen content of the flue gases may be increased or decreased to obtain the required oxygen concentration for the oil that is being processed, pipe 43 being connected to a source of nitrogen gas, carbondioxide or like gases, also to a source of atmospheric air. Pump 45 discharges the aeriform fluid, containing the required oxygen concentration, through pipe 46, heater coil 48, pipe 50 controlled by valve 5 I, and then into the lower section of reaction chamber I5, wherein it is mixed with the vaporized portion of the oil coming from heater coil II through pipe I3.

The aeriform fluid passing through heater coil 48 is preferably heated to a temperature ranging from approximately 800 to 1300 F. or higher, this temperature depending upon the temperature of the vaporized oil entering reaction chamber I5, which is so regulated that the resultant temperature of the mixed vaporized oil and heated aeridizing or dehydrogenation reaction has been added, will be approximately 800 to 1100 F. for the production of a motor fuel or gasoline stock to have an octane number of approximately 73 to 80, and approximately 1100 to 1300 F. or higher if a motor fuel or gasoline stock having an octane number of, say, to is desired.

The oil vapor, separated from the unvaporized portion of the oil being processed, mixed with the aeriform fluid, passes up through contact material IS in reaction chamber I5, wherein the oil is dehydrogenated to the required degree, cracked and reformed with the production of gaseous products, high boiling oils and a motor fuel having anti-detonating characteristics to the required degree. From reaction chamber I5 the products of the dehydrogenation, cracking and reforming reaction, and spent aeriform fluid, pass through pipe I9, heat exchanger 8, pipe 20, pressure relief valve 2| where the pressure may be reduced to approximately atmospheric, and then into the lower section of fractionating tower 22.

In fractionating tower 22 the higher boiling oils are separated by fractionation from the aeriform products and the motor fuel produced. A higher boiling distillate collects on separator plate 62 and continuously passes out of fractionating tower 22 through pipe 64 into the suction side of pump 66, the rate of flow being controlled by valve 65. The boiling range of the distillate collecting on separator plate 62 may range from about 300 to 600 F., depending upon the oil being processed and the products desired. Pump 66 discharges this higher boiling distillate, which is composed collects in residuum tank 26, together with the residual oil separated in the vaporizing section of reaction chamber I5. The higher boiling residual oils which collect in tank 26 may be conducted to other storage not shown through pipe 21, controlled by valve 28, after which they may be distilled and the distillate returned to the system and processed for the further production of motor fuel or gasoline stock, and/or marketed as a fuel oil.

The gasoline or motor fuel produced in vapor form, mixed with the othergaseous products, passes from the top of fractionating tower 22 through pipe 23 and into condenser coil 3 I, which is stationed in condenser box 30. A cooling fluid, such as water or brine, flows through condenser box 30, whereby the major portion of the motor fuel is condensed to a liquid. From condenser coil 3| the condensed motor fuel and gaseous products pass through pipe 32 and into gas separator 33, wherein the liquid motor fuel is separated from the gaseous products and passes through pipe 36, and is collected in tank 31.

The gaseous products, containing a certain percentage of the motor fuel, pass through pipe 34, controlled by valve 35, to an absorber not shown, therein the motor fuel retained by the gaseous products is separated by absorption methods known in the, art, and thereafter returned and mixed with the motor fuel or gasoline stock contained in tank 31. The motor fuel which collects in tank 31 is conveyed to other storage not shown by pipe 38, controlled by valve 39, and may be thereafter treated by known puri- 7 fication methods to produce a water white gasoline or motor-fuel oil stock with high anti-detonating characteristics, or it may be blended with other gasoline stocks to increase the anti-detonating characteristics, as heretofore stated.

The term marketable fuel oil as used in the specification and claims of this application is to be taken to mean a liquid hydrocarbon fuel oil as designated by the Bureau of Mines Technical Paper 323-B for Bunker Fuel Oil of the A, "13 or C grades.

While the process herein described is well adapted for carrying out the objects of the present invention, it is to be understood that various modifications and changes may be made without departing from the spirit of the invention, such, for example, as the use of other forms of elongated heaters or reaction chambers, and the invention includes all such modifications and changes as come within the scope of the appended claims.

I claim:

1. A method of processing hydrocarbon oil for the'production of motor fuel and a Bunker fuel oil, the steps which comprise, heating the oil under super-atmospheric pressure to a cracking temperature ranging from approximately 800 to 1300 F., passing the heated oil into a vaporizing zone and separating a vaporized portion of the oil from a primary residual oil; combining with the vaporized portion of the oil an aeriform fluid having a free oxygen content from 5 to approximately 18 per cent by volume, in quantities suflicient to reduce the hydrogen content of the vaporized oil to at least 14.3 per cent and to not less than 9 per cent by weight; passing the combined mixture of vaporized oil and aeriform fluid through a reaction zone at temperatures ranging from approximately 800 to 1300 F., and then separating by fractionation aeriform products, motor fuel and a higher boiling distillate from a secondary residual oil; combining the separated secondary residual oil with the primary residual oil to form Bunker fuel oil.

2. A method of processing hydrocarbon oil for the production of motor fuel anda Bunker fuel oil, as in claim 1, in which the aeriform fluid is air mixed with an inert gas.

3. A method of processing petroleum oil residuum for the production of motor fuel and a Bunker fuel oil, as in claim 1.

4. A method of processing hydrocarbon oil for the production of motor fuel and a Bunker fuel oil, as in claim 1, in which the pressure on the heated oil passing into the vaporizing zone is reduced to approximately 50 to 300 pounds.

5. A method of processing hydrocarbon oil for the production of motor fuel and a Bunker fuel oil. as in claim 1, in which the separated higher boiling distillate is continuously returned to the reaction zone and further cracked by thermo molecular decomposition for the further continubus production of motor fuel and secondary residual oil.

6. A method of processing hydrocarbon oil for the production of motor fuel and a Bunker .fuel

oil, the steps which comprise, heating the oil under superatmospheric pressure to a cracking temperature ranging from approximately 800 to 1300 F., passing the heated oil into a vaporizing zone and separating a vaporized portion of the oil from a primary residual oil; combining with the vaporized portion of the oil an aeriform fluid having a free oxygen content ranging from 5 to approximately 18 per cent by. volume, in an amount which will improve the anti-detonating characteristics of the vaporized portion of the oil; passing the combined mixture of vaporized oil and aeriform fluid through a reaction zone at a temperature ranging from approximately 800 to 1300 F., fractionating the reaction products and separating aeriform products, motor fuel and a higher boiling distillate from a secondary residual oil, combining the separated secondary residual oil with the primary residual oil to form Bunker fuel oil. 7. A method of converting high boiling hy drocarbon oil into low boiling hydrocarbon oil and a Bunker fuel oil, comprising the steps of heating an elongated confined stream of the high boiling hydrocarbon oil to a temperature ranging from approximately 800 to 1300" F., vaporizing a portion of the oil so heated in an enlarged zone and separating therefrom a primary residual oil, then introducing into thevaporized portion of the oil a heated gaseous mixture having a free oxygen content from 5 to approximately 18 per cent by volume, in quantities suificient to reduce the hydrogen content of the vaporized portion of the oil to at least 14.3 per cent and to not less than 9 per cent by weight; fractionating the reaction products and separating aeriform products, motor fuel and a higher boiling distillate from a secondary residual oil; combining the separated secondary residual oil with the primary residual oil to form Bunker fuel oil.

8. A method of processing hydrocarbon oil for the production of motor fuel and a Bunker fuel oil, the steps which comprise, heating the oil under superatmospheric pressure to a cracking temperature ranging from approximately 800 to 1300 F., reducing the pressure and passing the oil into a vaporizing zone and separating a vaporized portion of the oil from aprimary residual oil; combining with the vaporized portion of the oil an aeriform fluid having a free oxygen content from 5 to approximately 18 per cent by volume, in quantities sufficient to reduce the hydrogen content of the vaporized oil to at least 14.3 per cent by weight and to not less than 9 per cent by weight; passing the combined mixture of vaporized oil and aeriform fluid through a reaction zone at temperatures ranging from approximately 800 to 1300 F., and then separating by fractionation aeriform products, motor fuel and a higher boiling distillate from a secondary residual oil; combining the separated secondary residual oil' with the primary residual oil to form Bunker fuel oil.

MARVIN L. CHAPPELL.

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