US1308161A - Process of treating hydrocarbon oil. - Google Patents

Description

R. H. BROWNLEE.

PROCESS OF TREATING HYDROCARBON OILS.

APPLICATION FILED MAR. 29.1917- Patented July 1, 1919.

ROY H. BROWNLEE, OF PITTSBURGH, PENNSYLVANIA.

PROCESS OF TREATING HYDROCARBON OILS.

. Specification of Letters Patent.

Patented July 1., 1919.

Application filed March 29, 1917. Serial No. 158,165.

a process in which a hydrocarbon oil may' be so treated as to crack the same and obtain therefrom a yield of low boiling products,

such as commercial gasolene, which is either much higher than the percentage of such products naturally contained in the oii undergoing treatment or is formed wholly by the breaking up of the heavier hydrocarbons. A further object of the invention is to provide a process which is continuous and which is adapted for the cracking of hydro carbon oils of varying boiling paint and density to obtain a maximum yield of the low boiling liquid hydrocarbons constitut ing commercial gasolene, without excessive formation of permanent gases and carbon. A still further object of the invention is to provide a .process of such nature that the objects above stated are obtained by subjecting the higher boiling or heavier components of the oil to a continuously recurrent treatment, under conditions favorable for the cracking of the same, in the presence of a continuously decreased quantity of the vapors of the lower boiling hydrocarbons formed in the normal operation of the process.

The theory of operation of the present process depends upon the fact that the operation of cracking petroleum and its derivatives constitutes what is essentially a reversible chemical re-action. That is, when a certain proportion of the naturally contained heavier components of the petroleum have undergone a molecular splitting or cracking to form lighter or lower boiling products the re-action normally reaches a state of equilibrium due to the concentration of these products, so that a change of conditions, such as increased temperature, sufli;- cient to cause a continuance of the action will also result in an increased production of undesired end products. In the present process, however, the conditions are such that the vapors condensable into the liquid hydrocarbon products desired may be continuously withdrawn from the system, while the heavier components are retained for a further treatment under conditions in which there is a lessened concentration of the vaporized products into which they are to be decomposed. Generally stated the present process consists in introducing oil and a suitable gas, preferably superheated steam or a hydrocarbon gas, into a pipe system maintained at a temperature and pressure suitable for cracking the hydrocarbon oil undergoing treatment; this pipe system bemg so constructed and the process so conducted that vapors condensable into liquids or" a predetermined gravity and boiling point are continuously withdrawn from the system, while the heavier components which are carried by the gas are deposited in a liquid state throu hout the length of the pipe, and flow bac l iwardly therethrough so that they are subjected to a further cracking in the presence of a lesser concentration of the desired products than at the point of their separation.

In the accompanying drawings, Figure 1 is a diagrammatic plan View illustrating generally apparatus for conductingthe processof the invention; Fig. 2 is a vertical sectional view of the apparatus; and Fig. 3 is a detail view illustrating a modification for introducing both steam and a hydrocarbon gas into the pipe systems of the apparatus.

The general arrangement of the apparatu illustrated comprises a furnace 1 having therein one or more units or pipe systems 2 extending vertically thereof, a plurality of such units being shown throughout as such re-duplication is desirable for purposes of operating economy. Each of the units 2 is connected by suitable means with a steam line 3 leading from a boiler 4 and with an oil line 5 leading from an oil reservoir 6 and having therein a suitable pressure pump 7. As shown, each of the units 2 is connected at its discharge end to a suitable header or vapor line 8 leading to a water cooled condenser 9. In their preferred form, each of the units, or pipe systems, comprises a plurality of sections 10 which are vertically inclined and suitably supported in the furpace, and which are welded or otherwise suitably connected at their contiguous ends so as to form a continuous pipe having elbows 11, at each of which the horizontal direction in which the pipe extends is changed. At the lower extremity of the pipe is a steam injector 12 which, as shown, connects with a steam header 13 which supplies the injector of eachof the pipes and which receives steam from the superheating coil 14 which lies beneath the floor of the furnace and forms a continuatiOn of the steam line 3. In the elbow 11 immediately above the steam injector is located the oil inlet '15 to which leads an oil pipe 16 receiving oil from a line 5 under pressure of the pump 7 Adjacent the lower extremity of the pipeis located the drain pipe 18 for the withdrawal of residuum settling in this portion of the pipe.

In order to regulate the steam used, the steam line 3 is provided with a valve 19 and pressure gage 20, while a valve 21 is also provided in the connection 22 from the steam header to the injector 12. In order to regulate the inflow of oil each of the oil pipes 16 leading from the oil line 5 to each of the units is provided with an oil meter 23 and a valve or cook 24. The valve 25 and pressure gage 26 are located in the vapor line between the furnace and the condenser, and a valve 27 is placed in the outlet from the condenser, so that the pressure in the pipe systems may be uniformly regulated,

and the vaporized products condensed either under substantially atmospheric pressure or under higher pressure as may be desired. Pyrometer connections 28 are also provided in the uppermost sections of each of the pipe system 2 so that the temperature of each of the systems may be observed and the temperature desired may be uniformly maintained.

In conducting the process, the furnace is first fired to raise the pipe systems to a suitable temperature. This temperature naturally varies with the grade of oil to be treated, but is in each instance such as would be more than sufiicient to vaporize substanti'ally all the vaporizable components of the particular oil undergoing treatment if such vaporization were to take place under atmospheric pressure merely.

This definition of the temperature may be illustrated by taking crude petroleum as an example. In such case, if the crude petroleum is of such a grade that all its components,'disregarding residual tars or cokes, will pass over in the 4 form of vapor during ordinary distillation at a temperature of 800 degrees Fahrenheit,

.the temperature maintained in a pipe system employing the present process must be in excess of 800 degrees Fahrenheit; a temperature of from 800 degr'eesto 1200 degrees Fahrenheit being employed. A suitable vapor or gas is then allowed to flow through the pipes to expel air and build up a slight initial pressure in the system. If steam is used it is preferably superheated to a temperature of approximately 350 degrees Fahrenheit in order to increase the velocity of its passage through'the pipes. The inflow of oil is then started, and this is at first almost completely and immediately vaporized and serves to build up a high pressure withing the system, this pressure being regulated by means of either of the pressure regulating valves 25 and 27 and being preferably maintained in excess of five atmospheres.

As the operation proceeds a certain proportion of the oil as originally introduced will not be immediately vaporized, because of the existing high pressure, and will flow backwardly in a film on the walls of the pipe sections 10 lying below the oil inlet 15. This film of oil will be subjected during its passage to a cracking temperature and pressure, and successive portions, or components thereof will be continuously vaporized into vapors such as may be condensed to form products of the desired low boiling point and specific gravity, these vapors being carried forwardly through the system by the current of steam or gas therein. Also a certain proportion of the components of the oil which is originally carried on through the pipe system will separate out during its passage, such separated components being those which are not susceptible of cracking under the conditions of pressure, temperature, and concentration of the oil vapors caused by previous cracking, existing at the point of their separation. These components also flow continuously downward through the pipe system counter to the current of steam or gas therein and are gradually cracked as they reach points at which the concentration of the products previously cracked is increasingly less. During the entire operation the temperature, the rate of oil inflow, and the speed of the carrying gases may be so regulated that the composition of the vapors leaving the discharge ends of the pipe systems is maintained substantially uniform.

As illustrated in the drawings, the connections are arranged to utilize superheated steam as the gas which is to act as a carrier for the oil. The process may, however, be performed with a suitable permanent gas introduced into the pipe system under pressure, with or without the additional use of steam. This permanent gas is preferably a hydrocarbon gas, such as natural gas or the permanent gases formed during the operation of the process, since such gases serve to increase the concentration of the gaseous end products throughout the length of the system, and thus tend to prevent the continuance of the cracking operation beyond the point at which the resulting products are condensable. relatively inactive chemically, under the conditions of the process, such as superheated steam, is used, the gas used serves to prevent undue decomposition by conveying the vaporized portions of the oil throughithe system at a fair rate of speed, and also serves in some degree to modify the effect of the high temperature to which the oil is subjected.

In conducting the process it is possible to use both steam and a permanent gas, such as the hydrocarbon gases above mentioned, and thus secure the effect of both upon the oil undergoing treatment. Fig. 3 of the drawings illustrates a connection arranged to introduce steam, oil, and a permanent gas into the pipe systems. As illustrated, the superheated steam is introduced into the lower extremity of the lowermost pipe section by means identical. with those illustrated in Figs. 1 and 2 of the drawings, previously described. The oil is alsointroduced at the elbow next above the steam inlet, as in the previously'described construction, but a special connection is provided for introducing the permanent gas together with the oil. This arrangement comprises an injector 29 to which lead the oil pipe 16 and a gas pipe 29 leading from any suitable source of gas supply maintained under pressure. By means of this arrangement the 011 is atomized by the gas and is introduced with it in a commingled current,

so that the full effect of the gas in preventing undue decomposition ofthe oil is ob tained. With such connections the oil may be introduced merely under pressure, and

steam alone used for the carrying current, or a permanent gas may be introduced, in addition to the steam, either continuously throughout the time oftreatment or intermittently, as the operator may desire.

Due to the conditions above described the process is capable of cracking a relatively great proportion ofthe material undergoing treatment into a lower boiling product, such proportion depending somewhat upon the nature of the material. run. For in stance with a kerosene distillate the ield of commercial gasolene is extremely igh,

while with a petroleum residuum from which the naturally occurring lighter components of the petroleum have been removed the gasolene yield would be decreased. ln any case however, a relatively high percentage of the vaporizable components of the material submitted to treatment are converted into condensable low boiling products without an excessive formation of carbon or of permanent gas. The process is continuous so that re-treatment of the heavier components takes place during the continuous introduction of new ma- In case a gas which is ing a carrying current of terial without the necessity of drawing off such heavier components and re-treating them by a separate operation.

The process is obviously not limited to the size, form or arrangement of the means used for carrying it out, since a variety of forms or shapes of pipe might be arranged to, form pipe systems suitable for the process described. The arrangement of plant shown is merely general, and is illustrative of one only of a wide range of alternative devices and arrangements.

' What I claim is 1. The process of treating hydrocarbon oils to increase the yield of low boiling point liquid products, which consists in introducing a carrying current of gas adjacent the lower extremity of a vertically extending pipe system heated and maintained. under pressure, introducing the oil below the upper extremity of said pipe system, continuously separating the heavier components from the lighter vaporized products, and permitting a continuous reflux of the former through the system counter to the current of gas introduced thereinto so that the heavier components separated at any point in the system undergo a further treatextremity of said pipe system, continuously separating the heavler components from the lighter vaporized products, and permitting a continuous reflux of the former through the system counter to the current of gas introduced thereinto so that the heavier components separated at any point in the system undergo a further treatment in the presence of a lesser concentration of the lighter products than at the point of their separation.

3. The process of treating hydrocarbon oils to increase the yield of low boiling point liquid products, which consists in introducgas adjacent the lower extremity of a vertically extending pipe system maintained at a temperature in excess of 800 degrees Fahrenheit and under a pressure in excess of five atmospheres, introducing the oil below the upper extremity of said pipe system, continuously separating the heavier components of the oil from the lighter vaporized products, and, permitting a continuous reflux of the former through the system counter to the current of gas introduced thereinto so that the heavier components separated at any point in the system undergo a further treatment in the resence of a lesser concentration of the lig ter vaporized products than at the point of their separation. v

4. The process of treating hydrocarbon oils to increase the yield of low boiling point ual particles of oil from the current of gas and of the vapors formed, whereby every particle of oil may be subjected to repeated treatment at oints in the system containing a lesser concentration of-the products into which the oil is to be converted than at the point of its separation.

5. The process of treating hydrocarbon oils to increase the yield of low boiling point liquid. products, which consists in continuously introducing a currentof gas at a point adjacent the lower extremity of a vertically extending pipe system arranged to permit passage of the same throughout the length thereof, introducing the oil to be treated into said pipe system below the upper extremity thereof, maintaining said system throughout its length under pressure and at a temperature in excess of that required to vaporize substantially all the vaporizable components of the oil at atmospheric pressure, and permitting a repeated separati'on and reflux of individual particles of oil jfrom the current of gas and of the vapors formed, whereby every particle of oil may be subjected to repeated treatment at points in v the system containing a lesser concentration of the products into which the oil is to be converted than at the point of its separation.

6. The process of treating hydrocarbon oils to increase the yield of low boiling point liquid products, which consists in introducing steam adjacent the lower extremity of a vertically extending pipe system heated and maintained under ressure, introducing the oil and a hydrocar on'gas below the upper extremity of said pipe system; continuously separating out the .heavier components from the lighter vaporized products, and withdrawin the latterand permitting a reflux of the ormer through the system so that the heavier components undergo a further treattially all the vaporizable components of the oil at atmospheric pressure, introducing the oil and a hydrocarbon gas below the upper extremity of said pipe system; continuously separating the heavier components from the lighter vaporized products, and permitting a reflux of the former through the system so that the heavier components separated at any point in the system undergo a further treatment in the presence of a lesser concentration of the lighter products than at the point of their separation.

8. The process of treating hydrocarbon oils to increase the yield of low boiling point liquid products, which consists in introducing steam adjacent the lower extremity of a vertically extending pipe system maintained at a. temperature in excess of 800 degrees Fahrenheit and under a pressure in excess of five atmospheres, introducingthe oil and a hydrocarbon gas below theupper extremity of said pipe system; continuously separating the heavier components of the oil from the lighter vaporized products and permitting a reflux of the former through-the system so that the heavier components separated at any point in the system undergo a further treatment in the resence of a lesser concentration of the lighter vaporized products than at the point of their -separation.

9. The process of treating hydrocarbon oils to increase the yield of low boiling liquid products, which consists in introducing ROY H. BROWNLEE.

Witnesses:

WALTER S. KLEMANSKI, Sun B. FRITZ.

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