US1843700A - Process and apparatus for conversion of petroleum oils - Google Patents

Description

Feb. 2, 1932. w. F. SIMS ET AL 1,843,700

PROCESS AND APPARATUS FOR CONVERSION OF PETROLEUM OILS Original Filed May l, 1923 Patented Feb. 2, 1932 UNITE stares WILLIS IE. SIMS AND JACQUE C. MORCRELL,

OF CHICAGO, ILLINOIS, ASSIGNORS TO UNI- "VEBSAL OIL PRODUOTS COMPAPIY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA PROCESS AN D a:

.:. TUS FOB OONVERSION OF PETROLEUM OILS I Application filed May 1, 1923, Serial No. 835,822. Renewed November 7, 1928.

This invention relates to improvements'in a process and apparatus for the conversion of petroleum oils and refers more particular- 1y to a process relating to the destructive distillation of oils to produce relatively low boiling point oils from higher'boiling point oils, the product obtained having the characteristics of gasoline and the like.

The invention has to do also with a particular type of rectifying columnor tower evaporator in which are incorporated important novel features.

-One of the important objects of the invention resides in the application of heat procured from an internal source which is transferred to the ascending vapors meeting the liquid to be distilledand travelling in a counter-current direction. The particular source of heat is preferably from the distillation of hydrocarbon substances, that is petroleum or any of its distillates, or other hydrocarbons. The vapors may have originated in a cracking still or in an atmospheric pressure still" and a subsequent heat transfer effected by condensing the vapors and recycling them to come in radiating contact with the vapors produced by pressure distillation.

The single figure is a diagrammatic side elevational View of the apparatus.

Preferably the invention consists of heating and vaporizing a liquid hydrocarbon and subjecting. the vapors to a 'dephlegmating action, after which they are condensed and collected as liquid. distillate. This distillate is then recycled and caused to come in radiating contact or serve as a refluxing medium by cascading the liquid in a manner that the heat given up by the original vapors during the dephlegmation thereof will be utilized to re-v distill the recirculated condensate. The redistilled fractions are directed to a separate condensing and collecting means and comprise the final product. By utilizing the heat of the system in-this manner a most eflicient operation may be carried on and a high quality distillate obtained. I

Referring to the. drawing, the charging stock or oil to be treated is introduced from any convenient extraneous source through pipe 1 controlled by a valve 2 and is charged by means of a pump 3 through line 4 to a heating coil5, positioned in a side-fire furnace 6 which is preferably heated by means of gas' burners shown diagrammatically at 7 The particular type of apparatus used is of little importance other than that it is necessary to heat the oil as efliciently as possible and restrict the conversion of the oil as'far as possible to the vaporizing chamber 8, to which the oil is passed through a line 9 after it has been raised to a conversion temperature in the heating coil 5. A valve 10 is positioned in the transfer line 9 to control the flow of liquid or differential pressures, if such are desired.

The chamber 8 consists of an enlarged receptacle in which the oil is ermitted to collect'in a substantial body. %pper and lower removable heads furnish means for facilitating the cleaning of the chamber when the carbon collection therein has become objectionable. The vapors evolved in the chamber 8 pass off through the vapor line 11 controlled byvalve 12, While the unvaporized products and residual materials may be drawn off either continuously or intermittently through the draw-off lines 18 controlled by valves 14. These residual draw-oi? lines are positioned at different heights in the chamber in order that the liquid may be drawn off as the carbon collects. The chamber is equipped with try cocks 15 for ascertaining the liquid level of the chamber.

The vapors passing off from the expansion chamber are introduced to a harp-like heat interchanger or dephlegmator 16 positioned in the lower portion 17 of the rectifying column or tower evaporator 18. The vapors from the expansion chamber are introduced into the lower header 16b of the dephlegmator and pass through a plurality of pipes 16a connecting the lower header 16b and the upper header 160. 7

During their passage through the refluxing element the vapors are subjected to the cooling action of a liquid which flows over the exterior surface of the reflux condenser separating out the relatively high boiling 5 to the charging line 4 where it combines with the incoming charging stock and is recycled to the heating stage. The vapors which rise to the upper header 16c pass off through the vapor line 21 in which is interposed a valve 22 and are subjected to a final condensing action in the condenser coil 23 positioned in the condenser box 24. After passing through the condenser coil the vapors are collected as liquid distillate in the receiver 25. The valve 26 is interposed in the line between the condenser coil and the receiver. The receiver is equipped with a liquid level gauge 27 pressure gauge 28, and a pressure relief valve 29.

The distillate from the receiver 25 maybe returned to the top of the tower evaporator 18 through pipe 30 by manipulation of the valve 31. On being introduced to the rectifying column or tower evaporator the liquid distillate percolates down either over a series of pans which serve to divide the liquid into relatively small particles, or over any desired type of contact material which serves to expose a greater surface of the liquid distillate to the heat given up during dephlegmation of the vapors. This distillate after being cascaded over the contact plates or material in the tower evaporator passes down and circulates around the dephlegmating element 16 which is positioned in the lower portion of; the evaporator shown at 17. The heat given off by the dephlegmator 16 is sufficient to re-distill the liquid, the vapors rising through the tower and passing off through the pipe 32" to a condenser coil 33, and thence to the liquid receiver 34 where the redistilled product is obtained, and may be drawn off through the valve 35. A pressure relief valve 37, liquid level gauge 36, and a pressure gauge 38 on the receiver 34 serveto maintain the desired conditions of pressure in the secondary distillation system. This secondary system is preferably operated under atmospheric condition and therefore any excess pressure may be quickly relieved throughthe relief valvementioned. The unvaporized liquid which collects in the bottom of the chamber 17 about the dephlegmating element vmay be drawn ofl through the pipe 39 and charged by means of a pump 40 back to the line 1 which communicates with the suction side of the pump 3 whereby this liquid distillate is re-run with a charging stock and reflux condensate to the heating stage for re-treatment.

Thus the cracked vapors are passed from the expansion chamber into a primary dephlegmator. where partial condensation takes place, the reflux liquid passing back to the charging'line while the vapors pass aaaroo primary dephlegmator. Any remaining vapors which are being distilled over from the liquid in the base of the evaporating tower.

meetthe descending stream and furnish heat thereto. The tower may be arranged so that the greater part of distillation or evaporation takes place in the upper portion thereof.

, It is desirable to insulate the tower in order to have the maximum amount of heat taken up by the descending liquid. This ar rangement can be applied either to pressure stills or atmospheric stills. The primary out can be taken ofi from'the primary dephleg mator and the final cut taken off from the evaporating tower. Other liquid such as crude petroleum may be treated by pumping the crude into the evaporating tower and topping the heavy hydrocarbon for its lighter fractions, the residuum being passed off as charging stock into the cracking process. Whenoperating the. secondary distillation as a re-run unit it is preferably operated under atmospheric pressure.

By heating mid continent gas oil of approximately 32 Baum gravity to temperatures ranging from 600 to 900 F., under pressure ranging from 50 to 250 lbs. and rerunning the cracked distillate in the manner explained, a good yield of gasoline of new navy specification may be obtained in the final receiver shown at 34. v

It is desirable that the pressure distillate be treated before redistilling in the evaporating column, and suitable arrangements can be made so that thepressure distillate as it leaves the primary receiver can be brought into contact with, and treated by such reagents as sulphuric acid, water, caustic soda,

solutions of litharge in caustic soda and other reagents, in a properly determined order de. pending upon the type of pressure distillate.

Under certain circumstances and in the treatment of certain distilla-tes it may be de-:

42 is tapped into the bottom of the tower evaporator, and the steam of the desired character supplied from any convenient source, not shown.

WVe claim as our invention:

1. A process for converting oil, consisting in passing the oil through a heating zone nseegroo whereit is subjectedto a conversion temperature, in discharging the heated oil into an enlarged reaction zone wherein substantial. vaporization occurs, in passing the vapors from said reaction zone to a dephlegmator, in passing the uncondensed vapors from said dephlegmator to a condenser, and in collecting the resulting distillate, in passing said distillate directly to a zone of heat interchange with the vapors in said dephlegmator Whereby the distillate acts as a cooling medium for a the vapors in the dephlegmator and the heat of the vapors causes a re-distillation of said distillate, in passing the vapors resulting from such re-distillation of said distillate into intimate contact with additional quantities of said distillate to dephlegmate the last named vapors and toassist in the distillation of said additional quantites of distillate, in passing the uncondensed vapors of the distillate to a final condenser wherein they are condensed, and in collecting this final distillate, in returning reflux condensate withdrawn from said dephlegmator as well as such unvaporized distillate as may accumulate in said zone of heat interchange directly to said heating zone while preventing said reflux condensate and unvaporized distillate from contacting with vapors evolved from the oil prior to admission to said heating zone.

2. A process for converting oil, consisting in passing the oil through a heating zone where it is subjected to a conversion temperature, in discharging the heated oil into an enlarged reaction zone wherein substantial vaporization occurs, in passing the vapors from said reaction zone to a dephlegmator, in passing the uncondensed vapors from said dephlegmator to a condenser, and in collecting the resulting distillate, in directing said distillate to a zone of heat interchange with the vapors in said dephlegmator whereby the distillate acts as a cooling medium for the vaporsin the dephlegmator and the heat of the vapors causes a re-distillation of said distillate, in passing the vapors resulting from such re-distillation of said distillate into intimate contact with additional quantities of said distillate to dephlegrnate the last named vapors and to assist in the distillation of said additional quantities of distillate, in passing the uncondensed vapors of the distillate to a linal condenser wherein they are condensed, and in collecting this final distillate, in withdrawing reflux condensate from said dephlegmator, in separately withdrawing such unvaporizeddistillate as may accumulate in said zone of heat interchange and in returning such withdrawn reflux condensate and unvaporized distillate directly to said heating zone without permitting any of such reflux condensate and unvaporized distillate to again commingle with vapors evolved from the oil prior to the admission of such reflux condensate and unvaporized distillate to the heating zone, in continuously withdrawing heavy residual carbon-containing oil from said reaction zone to be isolated from the system, and in maintaining a superatmospheric pressure upon the oil undergoing conversion,

3. In an apparatus for converting oil, the combination with means for heating and vaporizing the oil, of a dephlegmating means connected thereto, condensing means connected to the dephlegmating means, means for passing the condensed distillate to a zone of subjected to re-distillation in said zone of heat 7 interchange, means for returning said withdrawn reflux condensate and unvaporized distillate directly and without contact with vapors to said heating means, and means for maintaining a superatmospheric pressure on the oil undergoing conversion.

4. In an apparatus for converting oil, the combination with a heating means, of vaporizing means, means for conveying oil from the heating means to the vaporizing means, dephlegmating means in communication with said vaporizing means, condensing means connected to said dephlegmating means, means for passing condensed distillate to a zone of heat interchange with vapors undergoing reflux condensation. in said dephlegmating means, to'cause redistillation of said distillate, means for passing the vapors evolved from said distillate into intimate contact with additional quantities of the con densed distillate to thereby dephlegmate said vapors and to assist in the distillation of said additional quantities of distillate, means for condensing vapors resulting from redistillation of said distillate, independent means forv withdrawing reflux condensate separated from the vapors in said dephlegmating means and for withdrawing unvaporized portions of the distillate subjected to redistillation in said zone of heat'interchange, means for uniting the withdrawn reflux condensate and unvaporized distillate and means for passing the united reflux condensate and unvaporized distillate directly and without contact with vapors to said heating means, and means for maintaining a lower pressure in said zone of heat interchange than is maintained upon the vapors undergoing reflux condensation in said dephlegmating means.

5. In the cracking of hydrocarbon oils, the improvement which comprises subjecting the oil to cracking conditions of temperature and pressure in a cracking zone, subjecting the evolved cracked vapors to dephlegmation to condense heavier insufliciently cracked fractions, returning the condensed insufliciently cracked fractions to said cracking zone for retreatrnent in the process, condensing the uncondensed portions of said cracked vapors thereby forming cracked distillate, utilizing portions of said distillate as the cooling medium for said dephlegmation thereby re-distilling said portions of the distillate, passing the vapors evolved by re-distillation of said portions of distillate in intimate contact with additional quantities of said distillateto thereby dephlegmate said vapors and to assist in the rcdistillation of said additional quantities of distillate, and separately condensing as the final product of the process the remaining uncondensed vapors of said distillate.

WILLIS F. SIMS. JACQUE C. MORRELL.

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