US1843385A - Process for treating hydrocarbon oils - Google Patents

Description

Feb. 2, 1932. G. EGLOFF PROCESS FOR TREATING HYDROCARBON OILS Filed June 12, 1920 Patented Feb. 2, 1932' PATENT OFFICE GUSTAV EGLOFF, OF INDEPENDENCE, KANSAS, ASSIGNOR .TO UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA PROCESS FOR TREATING HYDROOARBON OILS Application filed June 12,

The invention relates to improvements in a process and apparatus for treating hydrocarbon oils and refers more particularly to a pressure process for converting relatively heavy hydrocarbons into lighter oils having the characteristic of gasoline or the like.-

Among its salient objects are to provide a process which is carried on in a series of successive stages of increasing temperature and constant pressure; to provide a process which may be operated continuously, producing a high yield of pressure distillate of a high grade; 3, process in which the oil reflux from each stage is returned to be retreated in the succeeding stage except the last, whereby each stage is relieved of retreating the objectionable oil fractions formed therein; to provide a process which utilizes and conserves heat of the reflux condensate in each succeeding stage until from the final stage, it is drawn off as residuum; to provide an apparatus for the carrying out of this process and in general to provide a process and apparatus of the character referred to.

My process covers the pressure distillation of heavy hydrocarbon oils in a battery of ressure stills interconnected, and heated increasingly from still one to the last still in the battery. The condensed oils from the generated vapors in the dephlegmator in stead of returning to the still from which they were enerated are with theexception of the last still diverted to the next still in the battery. Y

The condensed oil from the dephlegmator of still No. 1, is diverted to still N o. 2; condensed oil from dephlegmator on still No. 2 is diverted to still N o. 3 and so on to the end still of the series. The temperature of the oil in the series of pressure stills increases progressively from still N o. 1 to the end of the battery of stills all under the same pressure.

I have found that in a batch still pressure distillation of heavy hydrocarbon oils, that if the time factor or the rate of distillation is maintained constant at constant pressure and increasing liquid temperature of the oil, the quality of the fractions of pres- 1920. Serial No. 388,405.-

sure distillate distilled over progressively decreases. In one series of tests when the batch still was operated at 90 lbs. pressure and distilling each 5 percent fraction of the oil in the still at the same rate, the Baum gravity of the 1st 5% fraction was 67.0 and the fraction between and was 45.0 Baum gravity. A batch pressure distillation produces-a .Widely variable cracked product, when the condensed oil from the dephlegmating system is allowed to fall upon the body of the oil in the still.

I have taken condensate from various parts of the dephle mating systems in pressure distillation and subjected them to similar conditions of cracking in which they were formed and found them much more refractory material to crack than the raw oil or the oil in the still. Now, by my process the condensate from the dephlegmator is diverted to the next still in the battery which is maintained .at a higher temperature than the still it was produced in, hence the velocity of cracking is greatly increased at the same pressure, due to the higher temperature the condensate is subjected to. 7

That a marked difference in the cracking result is obtained by diverting the condensed oil to a higher temperature is certain, for in unit time the velocity of the cracking reaction is enhanced. The complexity of the hydrocarbon cracking reaction is great, and the effect of increased temperature not understood, but that temperature profoundly modifies conversion of high molecular weight hydrocarbon to low molecular weight hydrocarbon is a fact. The chemical mechanics of hydrocarbon reactions resulting from thermal treatment at constant pressure is not-known at present. locities of chemical reactions as a function of temperature are recorded in the'literature. WVith very few exceptions all velocities of chemical reaction increase rapidly with rise of temperature. The followin carefully studied reactions illustrate the e ect of temperature upon same.

The single figure in thedrawing is a diagrammatic perspective view of the apparatus.

However, some ve-' Referring in detail to the drawing, three or more stills such as those shown at 1, 2, and 3, are mounted above furnaces 4, 5, and 6 re spectively. The raw oil is supplied .to the still 1 through the inlet line 7', controlled by valve 8, and a pressure pump 9. From this pressure pump, the oil may be introduced directly to the still 1 through the charging plpe 10, controlled by a valve 11 and pipe 13, regulated by a valve 14 or by throttling the valve 14, the oil charge may in part be introduced to the dephlegmator 15 through the line 16 regulated by valve 17. A circular spray nozzle 18 disseminates the oil in the dephlegmator and permits the oil vapors which rise to the dephlegmator from the first still or retort to more intimately contact a greater portion of the incoming oil and be more thoroughly dephlegmated, and preheated thereby.

That portion of the oil which is not vaporized in the first still is directed to the secondstill through the overflow line 19 regulated by a valve 20 and that portion not vaporized in the second still is introduced to the third still through the overflow line 21, regulated by a valve 22. From the third still a residuum drawofl 23 regulated by a valve 24 furnishes a means for removing the heavier oil and floatin the suspended carbon from the system. ore stills may be added to the system depending upon the type hydrocarbon oil to be cracked. Above the first still is mounted a dephlegmator 15, which is connected to the still by a vapor line 25. Interpos'ed in this line is a valve 26 for cutting out the first still from balance of battery when cleaning out carbon. A. T-connection 27 is shown for directing the reflux from the first dephlegmator to the second still through the connecting line 28 in which is interposed the valve 29. Goosenecks 30 connected to condenser coils 31, leading to receivers 32 furnish a condensing and collecting means for the vapors which pass off from the top of the dephlegm'ators. The condenser coils are mounted in the water condensing box 33. Each receiver is supplied with a pressure gauge 34, liquid draw offs 35 controlled by valves 36 and pressure relief lines 37 regulated by valves 38. Valves 26, 40 and 43 cut out the dephlegmating system when steaming and cleaning out the stills free of carbon.

Vapor line 42 via valve 43 directs the vapors from the third (or subsequent stills) to its dephlegmator 44. In the vapor line 39 is interposed a T-connection '45 similar to that shown at 27, in the vapor line 25. Deflectors 46 cast within the T-connections 27 and deflect the reflux oil which is condensed from each dephlegmator to the next succeeding still. By this means the reflux condensate which is produced by a dephlegmation of the vapors from each still instead of being returned to the same still for reis maintained under the lowest condition of temperature necessary for cracking the fresh oil, and increasing the liquid temperature in each succeeding still gave a higher degree of cracking than if cracked in one still;

The oil is introduced directly to the first still through the line 13, and the process operated continuously. However, the charging stock may be also introduced in part to the dephlegmator through the line 16.

An illustrative run of the process; using a 32.0 Baum gravity gas oil from a mid-continent crude is as follows:

A constant pressure of 95 lbs. was maintained upon the system, still N o. 1 having a liquid temperature of from 705 to 720 F. while still N o. 2 was maintained at a temperature of 722 F. to 735 F. and still No. 3 at temperatures between 734 F. to 750 F., while still No. 4 if such a still is used drew ofl residuum at a temperature of approximately 750 F. The Baum gravity of the pressure distillate from the battery of stills ranged between 50 and 5.3 when operatin normally upon a mid-continent gas oil. The percent age of pressure distillate distilling over of 52.0 gravity was 60.0 and contained 58 per cent of gasoline of 57.0 gravity or 34.8 per cent marketable gasoline on basis of oil used.

I claim as my invention: 7

1. The process of cracking hydrocarbon oils, comprising passing the oils successively through a plurality of stills adapted to be heated to a crackin temperature, in heating the oil in the first still to a liquid temperature not exceeding approximately 720 F., in taking ofi vapors from said still and introducing them to a reflux condenser, in returning reflux condensate to a next succeeding still of the series where the oil is heated to a temperature not exceeding substantially 735 F. in removing vapors from said still, and discharging them into an independent reflux condenser, in returning reflux condensate from said condenser to. a next succeeding still where the oil is heated to a temperature not exceeding approximately 750 F., in discharging vapors from said still into a reflux condenser, and in collecting the uncondensed vapors from each reflux condenser.

2. The process of cracking hydrocarbon oils, comprising passin' the oils successively through a plurality o stills adapted to be heated to a crackin temperature, in heating the oil in the first still to a liquid temperature not exceeding approximately 7 20 F., in taking ofi' vapors from said still and introducing them to a reflux condenser, in returning reflux condensate to a next succeeding still. of

the series where the oil is heated to a temperature not exceeding substantially 735 F., in removing vapors from said still, and discharging them into an independent reflux condenser, in returning reflux condensate from said condenser to a next succeeding still where the oil is heated to a temperature not exceeding approximately 750 F., in discharging vapors from said still into a reflux condenser, in separately collecting the vapors passing from each reflux condenser, and in maintaining a vapor pressure on the oil during distillation.

3. A process of oil conversion, consisting in maintaining a bulk supply of oil under cracking conditions of temperature and pressure in an enlarged zone, in continuously withdrawing unvaporized oil from said zone, in maintaining the supply of oil therein substantially constant by introducing thereto a streamof vcharging oil under a mechanical pressure, in passing vapors evolved from the oil in said enlarged zone to a 'dephlegmator, introducing into said dephlegmator a second stream of charging oil to act asa dephlegmating medium for the evolved vapors, in subjecting said second stream of oil together with reflux condensate resulting from the dephlegmation of the vapors to a higher temperature than that to which the oil is subjected in said enlarged zone while maintained under a superatmospheric pressure. 7

4. A process for cracking oil, consisting in maintaining a supply of oil under cracking conditions of temperature and pressure in an enlarged zone, in continuously withdrawin unvaporized oil from said enlarged zone an passing such unvaporized oilto a second enlarged .zone, in maintaining the supply in said first enlarged zone substantially constant by intro ucing thereto a stream of charging oil under a mechanical pressure, in subjecting the vapors evolved from the oil in said first enlarged zone to reflux condensation by assing such vapors in heat transfer relation with a second stream of oil, in passing the reflux condensate resulting from dephlegmation of the vapors together with said second stream of oil to the body of oil maintained in said second enlarged zone and in subjecting such bod of oil in the second enlarged zone to a higher temperature than that to which the body of oil in the first enlarge zone is subjected.

5. A process for cracking hydrocarbon oil which comprises maintaining a body of oil under cracking conditions of temperature and pressure, removin evolved vapors and passing the same to a ephlegmator, placing a stream of charging oil for the process under a mechanical pressure and dlviding such stream into sections, introducing one section of such stream into the body of oil undergo-

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