US1989737A - Conversion of hydrocarbons - Google Patents

Description

Feb. 5,. 1935. R. E. BURK TEMPEEATUZE co/vn/ Tio/w54?.

OXYGEN LN VENTOR.

ATTORNEYS Patented Feb. 5, 1935 UNITED STATES PATENT OFFICE CONVERSION F HYDROCARBONS poration of Ohio Application April 15, 1932, Serial No. 605,481

7 Claims.

This invention relates to the conversion of hydrocarbons, and more particularly the obtaining of low boiling products suitable for motor fuels, e'tc. It is among the objects of the invention to provide a system of conversion capable of operating upon various stocks, and with advantages in application and control of heat. Another object is the provision of means for attaining desired temperatures, without undue coking in heating coils or narrow passage-ways. Another object is the'provision of procedure making possible products with satisfactory knock-rating for motor fuel usage. Other objects and advantages will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be applied.

In said annexed drawing:-

The sole figure is a diagrammatic sectional elevation showing apparatus contemplated in the invention.

Referring more particularly to the drawing, there is shown a heating device, for instance in the form of a coil or bank of tubes 3 in a furnace chamber 4, red by any suitable means, as oil, coal, etc. Connecting with the outlet pipe 4 from the heater is a converting chamber 5. This may vary as to detail form. Preferably, it may be heat-insulated, or at least guarded against material heat loss, and for this it may be mounted so as to be surrounded by waste flue gases, or more desirably, may be lagged or covered with heat-` insulating material z. A draw-off line 6 from the bottom leads to a tank or other desired point of disposal, and an off-take 7 at the top leads to a condensing system, which may include fractionating apparatus in detail as may be desired. Connecting valso into the converting chamber is a line or pipe 8 for the supply of oxygen. Compressed pure oxygen may be provided from a suitable'source 9, or more conveniently ordinarily, air may be employed, furnished by a suitable compressor 1.

'Ihe oxygen orv air inlet into the converting chamber is desirably adjacent the inlet of the heated oil as coming from the heater 3. Preferably, the air or oxygen pipe is connected with the oil inlet in the form of .a spray-feed nozzle or jet 11, whereby the heated oil is nely divided or vaporized and exposed to the oxygen or air in a thorough Contact, and if the atomizer head or nozzle has its air feed supplied particularly externally of the oil, coking'up of the nozzle may be largely avoided. 5

In operating for the production of motor fuel for example, a suitable stock, as gas oil, heavy naphtha, or other crackable hydrocarbon material, is forwarded from a source of supply by pipe 12 to the heating coil 3. Preferably, I employ 10 a mixture of petroleum bottom or tar, and naphtha, as will be referred to more in detail below. The temperature applied in the heating coil is desirably sufficient to bring the oil up to cracking point, without however, allowing cracking to occur 15 in the coil. By operating' the furnace and through-put so that only a trace, or for instance not over one per cent of cracking occurs in the coil, it is possible to operate the latter practically continuously without coking trouble. The pressure in the coil need be only a few pounds or suicient for adequate through-put. Most usually a pressure of pounds or more is employed. If desired, the pressure may be carried to high ranges, as much as 1000-1200 pounds per square inch. The heated hydrocarbon stock, still chiefly in liquid state, is then discharged into the converting chamber 5 and exposed intimately.to the action of oxygen or air. The pressure in the converting chamber may range substantially with that in the coil, or preferably will be reduced, being released by suitable valve means 13 to a range for example, of' 12-125 pounds, desirably about 100 pounds, and may be controlled by suitable means at any preferred point beyond the outlet. With the oil :i5 thus already heated up to its cracking point, and then discharged into the presence of oxygen, a rapid breaking-down proceeds, and the extent of action can be controlled as desired, by regulation of the oxygen or air fed through valves 14 Il or l5. The temperature may be brought at least to 700 or 800 F. desirably, and on up to 1l25 F. or higher. The converted products are both of lower molecular weight, andof lesser hydrogen content. The products drawn off by off-take 'l 45 may be condensed and separated or fractionated with the recovery of the motor fuel and heavier fractions.

Some variations as to temperatures and pressures may be had, as indicated, depending upon 50 the contact time available in the converting chamber, its size, the pressure, volume of throughput, and nature of the stock. For example, with a gas oil heated and then subjected to a temperature of 11.25 F. in a converting chamber in 55 the presence of air, and at a pressure of l0 pounds, a contact time of 1.5 seconds is adequate. Again, as another example, gas oil is heated and discharged into the converting chamber, where it is treated in the presence of air, and at a tempera'- ture of about 950 F. and pressure of about 100- pounds per square inch, with a contact time of about 25 seconds.

By employing a mixture of petroleum residuum or tar and a naphtha, some remarkable advantages may be realized. The residuum may be the bottoms of a pipe still or other distillation, or from a cracking operation, as for instance cracking coil tar, or a mixture of distillation residuurn and cracking tar may be used. By naphtha is meant a distillate fraction containing hydrocarbons of the range available for motor fuel. The naphtha most advantageous in mixture is a naphtha which is not quite satisfactory as regards knock rating or one which contains heavy end components. The Knock rating of the nal motor fuel product attained is very notably raised, and may be gauged quite closely as desired, and furthermore, the odoris greatly superior to that or" the initial naphtha. Using for instance, a mixture of 60 per cent cracking coil tar and 40 er cent of a naphtha of initial B. P. 223 F. and final B. P. 508 F. and a feed rate of 26.7 cubic feet `of air per gallon of liquid fed, and a temperature of 1120o F. at the conversion chamber, a product may be had which cuts or fractionally d istills into a motor fuel having an octane knock rating of 78. The heavier remainder after distilling off the motor fuel, amounting to about 30.8 per cent of the total distillate, is an oil of about 39 B. viscosity suitable for domestic furnace and other likey burner usage. By operating at a lower temperature, the gas loss may be less, and a knock rating which is generally satisfactory may also be attained. IFor instance, with a temperature of 1060 C. and air feed of about 12.3 cubic feet of air per gallon of liquid fed, using the aforemen- I tioned mixture of 60 per cent cracking coil tar and 40 per cent heavy naphtha, a yield of a light fraction (38.5 per cent of total liquid charged) off at 460 F. may be had with a knock rating of about 6'7 octane rating, and a fraction of about 39.8

per cent of furnace or fuel burner oil. n

As another instance, starting with a mixture of 40 per cent cracking coil tar and 60 per cent of a naphtha whose knock rating is 26 octane rating, and employing a temperature of 950 F. and an air feedof about 24 cubic feet of air per gallon of the liquid fed, a yield of a motor fuel fraction having an octane rating of 54 and an amount 47.4 per cent o at 460 F. may be had, and a furnace Voil fraction of about 39 per cent.

If desired, the oxygen or air supply may be conditioned as to its Itemperature, by passing through a conditioner 16 on the way to the converting chamber. In the conditioner, the temperature is either raised by application of heat, or is lowered by cooling, as may be desired in any given case.

This application is a continuation-impart of my application Serial No. 552,566, filed July 23rd, 1931 now U. S. Patent 1,963,647.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any o-f the following claims or the equivalent of such, be employed.

. I therefore particularly point out and distinctly claim as my invention:-

1. A method of converting hydrocarbons, which comprises mixing a petroleum hydrocarbon too heavy for motor fuel and a petroleum naphtha and heating a flowing stream thereof to a temperature of Z-1125 F., then admixing with oxygen in a reaction zone to complete the conversion.

2. A method of converting hydrocarbons, which comprises mixing a petroleum residuurn too heavy for motor fuel and a petroleum napht'ia and heating a flowing stream thereof to a temperature of -700-l F., and admixing the hydrocarbons with oxygen in a reaction Zone to complete the conversion.

3. A method of converting hydrocarbons, which` comprises mixing a petroleum residuum too heavy for motor fuel and a petroleum naphtha and heating a flowing stream thereof at super-atmospheric pressure and to a temperature of TO0-1125 F., lowering the pressure, and subjecting the hydrocarbons to contact with oxygen in a reaction zone to complete the conversion.

4. A method of converting hydrocarbons, which comprises mixing a petroleum residuum too heavy for moto-r fuel and a petroleum naphtha and heating a flowing stream thereof under pressure of -1200 pounds per square inch and to a temperature of 700-1125 F., lowering the pressure to 12-125 pounds per square inch, and subjecting the hydrocarbons to contact with oxygen in a reaction zone to complete the conversion.

5. A method of converting hydrocarbons, which comprises heating a mixture of cracking coil tar and naphtha of unsatisfactory knock rating to a temperatureof '700-1125 F., and then subjecting the hydrocarbons to the action of oxygen in a reaction zone to complete the conversion.,

6. A method of converting hydrocarbons, which comprises heating a flowing stream of a mixture of a petroleum residuum too heavy for motor fuel and naphtha to a pressure of 15o-1200 pounds per square inch and temperature of '700-1125 F., lowering the pressure, and admixing air in a reaction zone to complete the conversion.

7. A method of converting hydrocarbons, which comprises heating a flowing stream of a mixture of petroleum residuum too heavy for motor fuel and naphtha to a pressure of 150-1200 pounds per 'square inch and temperature of '700-1125 F., re-

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