US2072524A - Process for converting hydrocarbon oils - Google Patents

Description

March 2, 1937.. D. 1H, MACE PROCESS FOR CONVERTING HYDROCARBON OILS Filed May 2, 1932 3 Sheets-Sheet 1 INVENTOR March 29 WBK D. H. MACE PROCESS FOR CONVERTING HYDROCARBON OILS Filed May 2, 1932 3 Sheets-Sheet 2 INVENTOR March 2, 1937. D. H. MACE ROCESS FOR CGNVERTING HYDROGARBON OILS Filed May 2, 1932 5 Sheets-Sheet 5 mNNN .ww Il SEQ gg .MH QN Y m Nv SS S551 hm. Nm m INVENTOR v wml f# 7W Patented Mar. 2, 1937 UNITED STATES PATENT OFFICE PROCESS FOR CONVERTING HYDROCAR- BON OILS poration of Delaware Application May 2, 1932, Serial No. 608,614

6 Claims.

This application is a continuation in part of my copending application Serial Number 26,572 filed April 29, 1925 for Process and 'apparatus for converting hydrocarbon oils.

This invention relates to the conversion under pressure of high boiling hydrocarbon oils into lower boiling products, and has special reference to a conversion process and apparatus of the so called coil and drum type, in which the oil is -decomposed or cracked by rapidly raising the temperature thereof in transit through a heating coil and then delivering it into an enlarged Idrum or chamber in which cracking temperatures and pressures are maintained.

One of the objects of the invention is to provide la process and system of this general character in which the bulk of the heat employed for the cracking operation is imparted to the oil in transit through the heating coil, while the maintenance of the desired cracking temperature in the drum or chamber is effected through the addition of relatively small quantities of heat through the introduction into the body of hot oil therein of highly heated hydrocarbon vapors and gases, hydrogen, or other vaporous or gaseous mediums.

Another object of the invention is to provide a combined liquid-vapor phase cracking process and apparatus in which the bulk of the heat is imparted to a flowing stream of liquid oil in transit through a heating coil and the highly heated oil delivered into a heat-insulated drum in which the vapors and gases from 'a vapor phase cracking operation are introduced for the purpose of either slightly raising the temperature of the liquid body therein to the desired cracking temperature or maintaining the desired cracking temperature therein by compensating for heat losses incident to radiation, decomposition, distillation, etc.

More specifically, it is an object of the invention to minimize and practically eliminate the usual carbon diiliculties resulting from oil cracking or decomposition by regulating the rate of heating the oil in transit through the heating coil so as to bring it to a cracking temperature at substantially its exit from the coil whereby the time element is so controlled as to avoid any substantial degree of cracking within the coil, and thereafter delivering the oil into a heatinsulated drum where the desired cracking temperature is sustained by the continuous admission of highly heated vaporous and gaseous products, preferably although not necessarily, from a vapor phase cracking operation. In this way no appreciable amount of carbon is even formed in the heating coil, while such carbon as is pro-duced by concentrated cracking in the drum is of such a character and is so thoroughly held in suspension in the vigorously agitated oil therein that it may be handled with facility without serious caking upon the unheated Walls thereof.

Another object of the invention is to provide a combined liquid-vapor phase cracking process and system of the coil and drum type in which the nal product of the commingled vapors evolved from the liquid phase and the vapor phase cracking operations shall retain the benecial qualities of both classes of conversion processes, whereby the advantageous slow burning and antiknock properties of unsaturated vapor phase cracked products may be combined with the wellknown desirable qualities of liquid phase cracked products in suicient proportions to produce a gasoline-like fuel of superior character for internal combustion engines. 0

Still another object of the invention is to provide an oil conversion process of the coil and drum type in which a close regulation of the cracking temperatures in the drum, or plurality of series-connected drums, may be obtained by automatically or otherwise regulating the amount or degree of auxiliary heat supplied thereto through highly heated vapors or gases from an external source-preferably from a vapor phase cracking operation-in response to Variations in temperature of the oil in said drum or in said individual drums.

A still further object of the invention is to provide a combined liquid-vapor phase cracking process of the above indicated character in which the heavier constituents of the commingled and combined evolved vapors are separated out and returned, while still hot, to serve as a supply of clean distillate for the vapor phase cracking operation, thereby avoiding the necessity of a preliminary distillation which is usually requisite for producing a charging stock of suitable quality for vapor-phase conversion. The process, therefore, operates after normal conditions are established, to supply oil of suitable character for its own operation in the vapor phase stage. Any excess of such clean distillate may be cyclically returned to the main heating coil for retreatment.

The cle-an distillate may also include or consist solely of gasoline fractions suitable to be reformed by cracking to increase the anti-knock value thereof. If desirable other gasoline fractions to be reformed may be supplie-d from an external source in conjunction With or in place of theV distillate mentioned.

These and other objects of my invention, and the features by means of which they are attained, will be more fully understood from the following description of the process in connection with the preferred embodiment of the apparatus illustrated in the accompanying drawings, in Which:-

Fig. 1 is a diagrammatic view of an apparatus or system constructed in accordance with the present invention and adapted for practicing my improved cracking process, and

Fig. 2 is a diagrammatic view of a modified form of apparatus or system likewise embodying the novel features of my invention.

Fig. 3 is a diagrammatic view of another modied form of system embodying novel features of my invention.

Referring to the drawings, and for the present more particularly to Fig. 1, the system comprises, in general, an elongated heating coil I2 of restricted cross section for heating the oil in transit to a cracking temperature; a heat insulated drum or still I0 for receiving the highly heated oil from the coil I2; an auxiliary converter I4, preferably comprising an elongated cracking coil or tube, of restricted cross section and adapted to crack the oil supplied thereto in the vapor phase and to deliver the resulting highly heated evolved vapors and gases into the body of hot oil in the drum I0 whereby the oil in the still is either raised to or maintained at an effective cracking temperature for the conversion of the oil in the liquid phase, a separator I6 for receiving the combined evolved vapors from the drum I0 and selectively condensing out the heavier constituents thereof, while allowing the lighter constituents of desired volatility to pass on; a condenser I8 for condensing the lighter constituents of the vapors, and a collecting tank 20 for receiving the ultimate light distillate.

The drum I0 may be of any suitable construction and is heat insulated by means of lagging 2|. It is provided with a residue drawoif pipe 22 having a valve 23. The drum is not heated externally and the body of already hot oil delivered thereto receives added heat solely from the vapors and gases evolved in the vapor phase cracking converter I4, which vapors are conducted by means of a heat insulated pipe 24 into the lower part of the still I0 against a deflector 25 by means of which the hot vapors are evenly distributed throughout the drum. The heat insulated pipe 24 is provided with a pressure valve 26 for controlling the passage of vapors therethrough and regulating the pressure on the converter I4.

The heating coil I2 preferably comprises an elongated coil of restricted cross section that is heated by the products of combustion from a suitable furnace 28 disposed below it. The temperature of the oil emerging from the exit of the heating coil may vary between 70D-900 F. but is more frequently maintained at approximately 800 F. A pressure upwards of 80 pounds may be maintained at the coil exit and in the drum, depending upon operating conditions and the character of the stock being treated. Ordinarily, however, a pressure of approximately to 150 pounds will be found suitable for a gas oil charging stock. The heating coil I2 is connected by means of an insulated pipe 29 with the still at a suitable point intermediate its ends. The heated oil is delivered into the drum I0 through an extension of the pipe 29 and against a deector 3I whereby the oil is distribcram uted evenly in the still. The separation of th distributing deflectors 25 and 3I functions to thoroughly agitate the oil and keep the carbon in suspension. The heating coil I2 is continuously supplied with a heavy oil, such for instance as paraffine gas oil, from a suitable source and the oil is forced into the heating coil I2 by a pump 32 through a charging line 33 which is connected to the inlet end of the coil. Other oils may, of course, be used and parafiine gas oil is specified merely for illustrative purposes as showing a particular oil which may be satisfactorily employed.

The auxiliary vapor phase converter I4 may be of any type suitable for vapor phase conversion and as illustrated is of a form similar to that of the heating coil I2 and comprises an elongated coil of restricted cross section that is highly heated by means of a furnace 35 disposed below it. The converter I4 is supplied under pressure with oil of a suitable character from a convenient source and the oil is forced into the coil by a pump 36 through a charging line 31 having a valve 38. For vapor phase conversion, the oil must be relatively clean and, therefore, until the normal operating conditions are established, a preliminary distillation of a suitable oil, such for example as parafiine gas oil, may be resorted to in order to produce an oil having desirable characteristics for this purpose.

As the oil is forced under pressure through the cracking coil I4 at a rapid rate, it is subjected to high cracking temperatures varying from 900 to 1300 F. and is cracked in the vapor phase. The pressure within the cracking coil I4 will exceed somewhat that being utilized in the drum I0 for the liquid phase cracking operation. The vapor phase conversion operation is not confined to these temperatures and pressures and may vary therefrom to a considerable extent, depending upon the character of the oil being treated and other operating conditions. The vapors and gas evolved in the cracking coil I4, including the converted and unconverted vapors, emerge therefrom at very high temperatures and are conducted through the heat insulated pipe 24 and delivered directly into the body of already highly heated liquid oil in the drum I0. The heat of the vapors and gas thus introduced into the still is utilized either to raise the body of hot oil therein to the desired effective cracking temperature or to maintain it at such cracking ternperature to bring about the conversion of the oil in the liquid phase Without the necessity of supplying external heat to the drum. The tempern ature in the still, after the normal operation of the system has been initiated, is maintained at form 700 to 900 F. although it may vary therefrom. At a temperature of 800 F. or somewhat less, the body of liquid oil in the drum will be converted at a satisfactory rate.

Thus it is apparent that the bulk of the heat is supplied to the oil While in the heating coil I2 and that hot gases and vapors are injected into the highly heated oil in relatively small quantities for the purpose of maintaining constant or regulating the cracking temperature of the already highly heated oil in the drum, and for compensating for heat losses occasioned by radiation and decomposition, or by distillation, provided the drum is used for distillation, as is usually considered preferable. It is in thel drum that the bulk of the cracking or decomposition is effected.

although a portion thereof may be carried 'on in the heating'coil I2 if desired.

Ordinarily, however, I consider it advisable to so regulate the temperature of the heating coil furnace 28 with respect to the rate of flow of the oil through the coil I2 that the oil in transit only reaches a suitable and effective cracking temperature substantially at the exit of the coil. The time element of cracking is thus controlled so that no material amount of cracking takes place in the heating coil. By reason of such careful regulation, no appreciable carbon can be formed in the coil. Hence, deposition of carbon, with attending local hot spots and clogging of the coil, is prevented. In the drum, however, the desired cracking temperature is sustained in the manner set forth, and because of the ample volume of the drum, the oil remains under cracking conditions for a suiicient period for the desired degree of cracking to transpire. The drum, being unsubjected to external heat and held at the desired cracking temperature solely by the heat of the vapors and gases from the vapor phase converter I4, which continually keep the body of oil in constant and vigorous agitation, the carbon accumulating therein as a result of cracking is of such character that it may be easily withdrawn with the residual oil and does not cake upon the unheated walls of the drum to an objectionable degree.

In order that the body of oil in the drum I0 may be maintained at a substantially constant predetermined cracking temperature, provision is made for automatically regulating the temperature of the vapors and gases introduced thereinpreferably from the vapor phase cracking operation. For this purpose a thermocouple 39 is positioned in the wall of the still with its inner end projecting into the body of heated oil therein. When the temperature decreases or increases beyond predetermined limits, the thermocouple acts to operate a suitable automatic valve-actuating mechanism 40 which is connected with the fuel supply line 4I of the furnace 35 through which fuel is'supplied to the burner 42, whereby the supply of fuel to the burner 42 is automatically increased or decreased, as may be required. Accordingly, the temperature of the heated vapors andgases introduced into the still Il] is raised or lowered sufficiently to maintain the body of oil in the still at a substantially constant predetermined temperature. Of course, the charging rate of the converter might be regulated in order to vary the temperature of the cracked vapor phase products, if desired, or in any suitable means of regulating the temperature or amount of vaporous products delivered into the drum may be employed.

The intermingled vapors evolved from the liquid phase cracking operation in the drum I0, together with those of the vapor phase cracking operation in the converter I4, are preferably withdrawn Afrom the still through an insulated vapor line 43 and are conducted to the separator I6, wherein a separation of the lighter `and heavier constituents is effected. The lighter constituents of desired volatility emerge from the upper end of the separator I6 and pass through a pipe 44 into the water-cooled condenser I8 in which the vapors are condensed. The condensed distillate is then discharged and collected in the receiving tank 2li which is connected to the condenser by a pipe 46. 'I'he receiving tank 20 is provided with a gas outlet 41having a valve 48 and a discharge outlet 49 having a valve 50, by

means of which the operating pressure of the system is regulated and maintained.

The heavier constituents vof the vapors are condensed in the separator I6 and this hot condensate is conducted through an insulated pipe 5I to a suitable pump 52 (preferably a surge pump) 'by which it is forcibly returned While still hot to the system. This cyclic return of condensate may bev through an insulated pipe 53, having a valve 54, which connects with the charging `line 31 of the vapor phase converter I4, or through an insulated branch pipe 55, having a valve 56, which branch pipe connects with the charging line 33, of the heating coil I 2.V Thus,

by closing valve 56 and opening valve 54, the

clean condensate from separator I6 is pumped back through the pipe 5I, pump 52, pipe 53, and line 31 to the vapor phase converter I4 in which it is again used as the oil supply, or to supplement `an extraneous supply, for the vapor phase conversion. If the amount of condensate returned from the separator I6 is too great to be conveniently handled by the converter I4, the valve 56 in the branch pipe 55 may be opened'to permit a portion, at least, of the condensate to be forcibly recharged `into the heater I2 by the pump 52.

After the process has been brought up to normal operating conditions, the condensate produced in the separator I6 may be of suflicient quantity to be utilized to entirely replace the clean distillate v"originally supplied to the converter I4, as hereinbefore described. In this way the process, after normal operating conditions are establishedproduces its own supply ofclean distillate of a character suitable for the vapor phase cracking operation, so that the auxiliary supply of clean distillate may be either discontinued or substantially reduced. Of course, ii'

necessary, a small amount of preliminarily.

cleaned distillate may at any time be charged into the converter I4 through the pipe 31.

In one of its aspects, the invention is independent of the utilization of vapor phase cracked products for the heat regulation of the crackingA cial properties of liquid phase cracking in such proportions as to produce a particularly desirable and superior motor fuel for internal combustion engines. Moreover, by carrying on the combined liquid-vapor process in the manner described, the characteristics of the ultimate distillate are believed to be considerably improved by reason of chemical reaction between the interrningled vapors of the vapor phase and liquid phase cracking ,operations during the treatment.

The modied form of my invention as illustrated in Fig. 2 is similar in many respects to that illustrated in Fig. l, except that instead of a single cracking still or drum, a plurality or battery of series-connected insulated stills are employed. The several drums or stills 6U, 6I, 62, and 63 constituting the battery are connected by means of vapor lines 64 and liquid level lines 65. Each of the stills is provided with a residue drawoiT line 66 controlled by a valve 61 and all of the `draw-.off lines connect with a common discharge However, it is deemed espepipe 68. The stills are not externally heated but are covered with suitable heat-insulating material to conserve the heat Within; v

The rst still of the series is connected with the heating coil I2 by the insulated pipe 29, as was the single still I0 illustrated in Fig. 1 and already described. Similarly, the coil of the vapor phase converter |4 is connected to an insulated pipe 24 having branches 69, 10, 1| and 12 connected severally with stills 60, 6|, 62 and 63, respectively, and each of the branch lines is controlled by a valve 13.

Theoperation of the modified formV of my invention is in most respects like that described in connection with Fig; 1, except that the highly heated oil fronrthe'heating coil |2 enters the first still 68 of the batteryand overflows through liquid .level lines into the succeeding stills. The gases and vapors evolved inthe vapor phase cracking operation are introduced into the several stills through the insulated line 24 and its branch pipes 69, 18, 1|, and 12, in quantities sumcient to maintain the heated oil in the several stills at the desired cracking temperatures, or to raise 1 the temperature of the oil in the stills to the desired cracking temperatures.

By means of the valves 13 in the several branch lines 69, 10, 1| and 12, independently regulated quantities of hot vapors may be introduced into any one or all the stills to maintain them at the cracking temperatures determined upon. Obviously, the operation of these valves may be rendered individually automatic by providing the several stills with temperature-regulating devices as described in connection with Fig. l, or if preferred, a single such device may be employed to operate all the valves concurrently, or to regulate the supply of fuel to the burner 42 of the vapor phase cracking converter.

The vapors and gases resulting from the combined liquid-vapor phase cracking operations, pass from the several stills through the insulated vapor line 43 to the separator I6 wherein a separation of the heavy and lighter constituents takes place, the lighter constituents being conducted through the condenser |8 and collected in the tank 20 as the ultimate light distillate. The heavy constituents are pumped back either to the vapor phase cracking coil I4 or to the heating coil I2 as already described.

lThe system shown in Fig. 3 is the same as that of Fig. l., with the addition of a second separator and auxiliary pipe lines and valves. In Fig. 3 reference nuineral 16 indicates a second separator connected to the vapor pipe 44 of separator I6 by means of conduit 11 having a shut off valve 18. This conduit is adapted to pass vapors from the vapor pipe 44 of the first separator I6 into the lower part of a second separator 16, wherein the vapors are subjected to condensation resulting in the liquefaction of the heavier constituents thereof such as gasoline fractions suitable for reformation.

A valve 19 is furnished for preventing the passage of vapors from separator I6 to condenser |8 when it is desired to use also the second separator 16, and a pipe llhaving valve 8| 'serves to conduct vapors from the second separator to the pipe 44 leading to the condenser. Condensate from the separator 16 may be passed through pipe lines 82 and 83 into pipe 5I leading to pump 52, and these two lines are supplied with shut off valves 84 and 85 respectively. Conduits 86 and 81 having shut off valves 98 and 9| respectively are connected to. pipes 82 and 83, the former conduit. serving tosupply to the'system gasoline fractions suitable for reformation while the latter conduit having pump. 92 therein connects with the supply pipe line of vapor phase converter I4. An auxiliary pipe line 88 having shut off valve 89 connects conduit 86 with pipe 5| leading to the liquid phase and Vapor phase converters. Pipe lines 82 and 83vas- Well as conduit 81 are heat insulated to prevent heat losses from the products passing therethrough.

In operation, by closing valves 19, 89, 98 and 9| and opening valves 18, 8|, 84 and 85, condensate from the bottom of separator 16, such as gasoline fractions suitable for reformation, may be combined with the condensed heavier constituents removed from separator I6, for recycling lto either or both of the cracking coils. Or if desirable the condensate from separator 16 may be directed entirely to the vapor-phase converter I4 by closing valve 85 and opening 9|. Also by properly throttling these two valves the condensate in question may be directed to both pipe 5I and conduit 8-1 in any proportions selected.

GasolineV fractions suitable for reformation may be injected into either pipe 5I for passage to the liquid phase coil or vapor converter, by opening valve 89-,or these fractions may be caused to flow to' the'vapor phase converter by opening valve 98 and closing 85; Alternatively such fractions may be passed both through pipe 83 and conduit 81 with condensate from separator 16, by opening the proper valves.

Separator 16 may be entirely segregated from the system by closing valves 18, 8| and 84, in which case the valve 19 would be opened to permit the vapors from separator I6 to pass directly to condenser I8 as in Fig. l.

The added separator'and pipe lines serve to supply additional clean products to the vapor phase converter, for cracking at high temperature in the vapor phase. This cracking causes reformation of the gasoline fractions such as to increase the anti-knock value thereof, whereby the antiknock rating of the product produced by the entire system is increased. Any deficiency in the amount of gasoline fractions Withdrawn from the bottom of separator 16 may be made up from an'extraneous source represented by conduit 86, or the extraneous source may be used entirely, the separator 16 being isolated from the system by closing valves 18, 8| and 84. In this case the vapors would pass directly from the separator I6 to condenser I8.

Although the invention has been set forth for illustrative purposes as embodying more or less specic details of operation and structural arrangement, it will be understood that many modications and variations thereof may be made without departing from the spirit and scope of the invention in certain of its aspects. Therefore, only such limitations should be imposed as are indicatedin the appended claims.

I claim:

1. The process of converting high boiling hydrocarbon oils into lower boiling products which comprises forcing oil under pressure through a heating coil of restricted cross section wherein the oily is raised to a cracking temperature, delivering the highly heated oil into a body of oil in the rstof a plurality of bodies of oil maintained in a plurality of series-connected stills, through which the oil flows in succession, maintaining predetermined cracking temperatures in the respective stills by delivering directly to the body of oil in each's'till regulated quantities of cracked vapors resulting from a vapor phase cracking operation, and withdrawing heavy residue and carbon from the last still of the series.

2. The process of converting high boiling hydrocarbon oils into lower boiling products which comprises subjecting oil to a cracking temperature in transit through a heating coil, delivering the heated oil into the ilrst of a plurality of bodies of oil maintained in a plurality of series-connected stills through which the oil flows in succession,

cracking oil in the vapor phase in a separate heating coil, delivering the vapor phase cracked products into the bodies of oil in each of the respective stills to maintain predetermined cracking l5 temperatures therein and crack the bodies of oil in the liquid phase, completing the cracking in the stills and removing the mixed vapors of a liquid phase and the vapor phase cracking operations from the stills, separating out heavier constituents 20 thereof by partial compensation, returning resulting hot condensate to the vapor phase cracking coil to be cracked therein and maintaining superatmospheric pressure upon the oil throughout the operation.

3. The process of converting high boiling hydrocarbon oils into lower boiling products which comprises subjecting oil to a cracking temperature in transit through a heating coil, delivering the heated oil into the first of a plurality of bodies of oil maintained in a plurality of series-connected stills through which the oil-ows in succession, cracking oil in the vapor phase in a separate heating coil, delivering the vapor phase cracked products into the bodies of oil in each i of the respective stills to maintain predetermined cracking temperatures therein and crack the bodies of oil in the liquid phase, completing the cracking in the stills and removing the Iixed vapors of the liquid phase and the vapor phase cracking operations from the stills, separating out heavier constituents thereof by partial condensation, returning a portion of the resulting hot condensate to the vapor phase cracking coil to be cracked therein and the rest of said condensate to said heating coil rst mentioned, and maintaining superatmospheric pressure upon the oil throughout the operation.

4. The method of converting higher boiling oils into lower boiling oils which comprises heating a conned flowing stream of fresh oil charging stock to cracking temperature under superatmospheric pressure, passing the stream of highly heated oil into an enlarged reaction zone wherein further cracking of the highly heated oil occurs, passing resulting cracked products from said reaction zone intoa separate enlarged zone, wherein vapors separate from residue, removing vapors from said zone last mentioned and subjecting them to fractional condensation to separate vapors of desired boiling range from heavier fractions as condensate, passing condensate so formed through a separate heating zone wherein it is raised to a cracking temperature, introducing resulting highly heated condensate into said enlarged zone second mentioned at a point remote from that at which vapors are removed therefrom, and condensing the fractionated vapors to form a desired distillate.

5. The method of converting higher boiling oils into lower boiling oils which comprises heating a confined flowing stream of fresh oil charging stock to cracking temperature under super.- atmospheric pressure, passing the stream of highly heated oil into an enlarged zone wherein a cracking temperatureis maintained and vapors separate from liquids, passing separated liquids from said enlarged zone into a separate enlarged zone, wherein vapors separate from residue, subjecting resulting cracked vapors to fractional condensation to separate vapors of desired boiling range from heavier fractions as condensate, passing condensate so formed through a separate heating Zone wherein it is raised to a cracking temperature, introducing resulting highly heated condensate into said enlarged Zone second mentioned at a point remote from that at which vapors are removed therefrom, and condensing the fractionated vapors to form a desired distillate.

6. The method of converting higher boiling oils into lower boiling oils which comprises heating a confined flowing stream of fresh oil charging stock in a heating coil to cracking temperature under superatmospheric pressure, passing the stream of highly heated oil into a primary enlarged zone wherein a cracking temperature is maintained and vapors separate from liquids, passing resulting cracked products from said primary enlarged zone into a second enlarged zone wherein separation of vapors from liquids occurs, preventing the recirculation of liquids thus separated through said heating coil, removing vapors from said second enlarged zone and subjecting them to fractional condensation to separate vapors of the desired boiling range from heavy fractions as condensate, passing condensate so formed through a separate heating zone from which cracked residual oil is excluded wherein it is raised to a cracking temperature, introducing resulting highly heated condensate into said second enlarged zone, preventing the recirculation of cracked residual oil through said separate heating zone, and condensing the fractionated vapors to form a desired distillate.

DONALD H. MACE.

CERTIFICATE OF CORRECTION.

Patent N0. 2,072,524. March 2, 1937.

DONALD H. MACE.

of the above numbered patent requiring correction as follows: Page 3, first Column, line 55, strike out. the word "in"; page 5, first column, line 3l, claim 5, for "oil-flows" read oil flows; and second column, line 50, claim 6, strike out "from which cracked. residual oil is exo1uded"; and that the said Letters Patent should be road with these corrections therein that the same may conform to the record of the case in the Patent Office. y

Signed and sealed this 30th day o March, A. D. 193'?.

Henry Van Arsdale (Smil) Acting Commissioner of Patents.

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