US2035037A - Process and apparatus for converting hydrocarbon gases and liquids - Google Patents

Description

March 24, 1936.

M. P. YOUKER PROCESS AND APPARATUS FOR CONVERTING HYDROCARBON GASES AND LIQUIDS Filed Feb. 29, 1952 ATTO EY.

WM da/ mummxmR MIR Patented .Man 24, 1936 PROCESS APPARATUS FOR CONVERT- ING HYDROCARBON GASES AND LIQUIDS Malcolm P. rouker, Bartlesville, okla., assigner to Phillips Petroleum Company, Bartlesville, Okla., a corporation of Delaware Application February 29, 1932, Serial No. 595,902

9 Claims.

This application has reference to the conversion of hydrocarbon liquids such as crude oil, gas oil, or fuel oil or the like, or mixtures of said liquids and hydrocarbon gases or hydrogen, and has par- .3 ticular reference to the conversion of these materials into gasoline. An object of my new invention is to provide a process and apparatus by which such conversion may be obtained without the excessive formation of coke in the apparatus l used. This object and other objects which will be made apparent in the following specification are accomplished by my new process. In the conversion of hydrocarbon materials accomplished by passing these materials through a tube in which l they are heated to high temperature and held under pressure I have found it advantageous to rapidly heat the materials passing through the first portion of the tube to conversion temperature and to only gently heat the latter part of the tube 30 in which the conversion of .the already heated materials is obtained. Various methods of accomplishing this and various disclosures pertaining to this process have been given in previous applications for patent filed by the present applicant. In this present application further disclosures regarding this process will be made, with particular reference to the manufacture of motor fuel in a combined crude and cracking still in which either crude oil, or gas oil, or fuel oil or the like may be converted to motor fuel.

My new improvements will be understood from the following specification taken in connection with 'the attached drawing on which a form of apparatus by which my new improvements may be .3 applied is illustrated.

Referring to the drawing, the numeral I designates arfurnaceTi thebottom of which is mounted a gas burner 2. Any suitable means of firing combustible material in the bottom of this furnace lo may, of course, be utilized. The near side of furnace I is shown cut away, revealing the disposition of a heating tube which passes therethrough. The numeral 3 designates an unred furnace which may be heated by gases of combustion leaving the furnace I. The near side of furnace 3 is shown cut away', revealing the disposition of a conversion tube which passes therethrough. A smoke stack 4 is connected to the top of furnace I by a breeching 5 in which is mounted a damper 6. A breeching 'l in which is mounted a damper 3 is connected into breeching 5 at a point between damper 6 and furnace I and leads from breeching 5 into the top of furnace 3. A breeching9 leads from the bottom of furnace 3 into smoke stack 4 at a polnt below the point of entry of breeching 5 into smoke stack 4. A breeching I 0 in which is mounted a fanII connects into smoke stack 4 at a pointsintermediate between the points of entry of breechings 5 and. 9 into smoke stack 4 and leads into breeching 'I at a point between 5 damper 8 and furnace 3. A damper I2 is mounted in breeching I 0. The fan II may be operated to circulate gases of combustion from the smoke stack 4 through breechings III and 1 and thence through furnace 3 and breeching 9 back into lo smoke stack 4. An air intake I9 which may be opened or closed and through which the fan II may, by closing damper I2, be caused to intake air from the atmosphere is provided in order to permit cooling of gases circulated through furnace 15 3. Gases of combustion developed in the bottom of furnace I flow upward through furnace I and thence through breeching 5. By means of par-V tially closing damper 6 and partially opening damper 8 a portion of the gases of combustion 20 which flow from furnace I through breeching 5 may be caused to flow thence through breeching 'I and thence downward through furnace 3 and thence through .breeching 9 into smoke stack 4. A heating tube I3 leads from a pump I4 through 25 furnace I to a point P1 between furnace I and furnace 3. The pump I4 is in communication with a supply of hydrocarbon material which is to be converted and operates to force such material through the heating tube I3 to the point P1. 30

-A portion of the heating tube I3 is so arranged that flow of materials through this portion of heating tube I3 is concurrent to the ow' of gases of combustion through furnace I. Another portion of the heating tube I3 is so arranged in the 35 furnace I that ow of materials through this portion of heating tube I3 is countercurrent to the flow of gases of combustion through the furnace I. Some other arrangement of the heating tube I3 in the furnace I may be utilized to carry out this 40 process; however, this particular arrangement may be found advantageous, as will be described later. A conversion tube I5 is connected to the outlet of heating tube I3 at the point P1 and leads through the furnace 3. While the disposition of conversion tube I5 in the furnace 3 is such that flow of materials through the conversion tube I5 is concurrent to the ow of gases of combustion through the furnace 3, an arrangement of the conversion tube I5 such that flow of materials 50 through Athis tube would be countercurrent to the ow of gases of combustion through furnace 3 would be satisfactory. Insulating tubes 20 are sections `of thin metal tubing which may or may not be slipped on over portions of conversion tube I5 to prevent gases of combustion coming in direct contact with conversion tube I5. A valve I6 is mounted atthe outlet end of the conversion tube I5 and may be utilized to regulate the pressure l maintained in heating tube I3 and conversion tube I5. A thermometer II is installed at the point P1 in the junction of heating tube I3 and conversion tube I5 and indicates the temperature of materials passing through these tubes at the point P1. A thermometer I8 is mounted in the conversion tube I5 at a point between furnace 3 and valve I6.

Hydrocarbon materials which are to be converted will be forced by pump I4 through heating tube I3 to the point P1 and thence through conversion tube I5 and valve I5. Furnace I will be fired to an extent suchthat the materials passed through the heating tube I3 will be heated in passage therethrough to a conversion temperature, Which in most cases will lie between 800 F.

and 950 F. Materials which have passed through heating tube I3 and which arrive at the point P1 already heated to conversion temperature will flow thence through conversion tube I5 and through valve I6. The materials passing through conversion tube I5 should be heated only very gently if at all. In most casessome heat is absorbed by the conversion reaction going on in materials passing through the conversion tube I5 and if no heat is supplied thereto the temperature o f materials passing through conversion tube i5 will decrease therein. It may be desirable to :supply heat to materials passing through ccnversion tube I5 in quantity such as to offset radiation losses and to supply at least a portion of the heat absorbed as a result of the conversion reaction. The temperature of materials passing through conversion tube I5 should preferably be maintained about constant or in case this material should be heavy oil, such as fuel oil, it is preferable that the temperature of materials passed through the conversion tube I5 be permitted to decrease in passage therethrough 10 or 15 degrees Fahrenheit. The temperature of materials passed through conversion tube I5 should in no case be increased in passage therethrough more than 50 or degrees Fahrenheit, and heating therein to this extent will usually cause an excessive deposition of carbon therein. u

It should be understood that this process may be successfully used for converting comparatively light hydrocarbon materials to comparatively heavier hydrocarbon Vmaterials; for instance, hydrocarbon gases which result from cracking oil in the conventional manner may be successfully converted to synthetic crude oil containing a high percentage of ordinary gasoline. In carrying out conversion reactions of this kind, the reaction will be found in some cases to be exothermic and in such cases it may be found desirable to supply no heat to the conversion tube I5 and it may even vrbe found desirable to cool the conversion tube I5 `by means of intaking air with the fan II and circulating the same through furnace 3 or by permitting the conversion tube I5 to cool by radiation of heat. In the conversion of hydrocarbons by nor decrease more than 10 F. per 100 feet of the conversion tube I5 in passage therethrough.

Several means by which the gentle regulated heating of materials passing through conversion K tube I5 may be accomplished are included in the apparatus shown on the drawing.

Increasing the length of that part of heating tube I3 through which flow of materials therethrough is countercurrent to the flow of gases of combustion through the furnace I and decreasing the length of that part rf the heating tube I3 through which theflow of materials is concurrent to the flow of gases of combustion through the furnace I will result in decreasing the temperature of the gases of combustion which leave the furnace i and which are utilized to heat materials passing through the conversion tube I5. The relation of the flow of materials through the heating tube I3 with respect to the flow of gases of combustion through furnace I may be so arranged that the temperature of the gases of combustion which have passed over heating tube I3 will be less than 200 F. above the maximum temperature to Which materials are heated While passing through the heating tube I3 and thus gases of combustion leaving furnace I will be made available for heating conversion tube I5 having a temperature of less than 200 F. above the temperature of materials entering the conversion tube I5. In most cases it is desirable that the heating tube I3 be so arranged in the furnace I that gases of combustion leaving furnace I and entering furnace 3 be in excess of the temperature of materials entering conversion tube I5, but in any case the temperature of such gases of combustion should preferably be not more than F. in excess of the temperature of the materials entering the conversion tube I5.

The temperature of gases'of combustion leaving furnace I and entering the furnace 3 through breeching 'I may be reduced by opening damper I2 and operating fan I I to mix with these gases comparatively cooler gases of combustion which have already passed through furnace 3.

The quantity of gases of combustion passed from the furnace I through the breechings 5 and I thence through the furnace ."3 and thence through breeching Q into smoke stack i Will be regulated by operating the damper 0.

Thecguantity of air passed through the furnace I and the initial temperature of gases of combustion developed therein Will be regulated by manipulation of the damper E in connection with the operation of the damper 3.

Heat should be applied to materials passing through the heating tube I3 in such a manner as to raise the temperature of the materials passing therethrough preferably at the average rate of 15 to 30 degrees Fahrenheit per 100 feet of the heating tube I3 and certainly at an average rate in excess of 6 F. per 100 linear feet of the heating tube I3. f

`liz'ailure to supply heat to materials passing through the heating tube I3 rapidly as outlined will result in excessive deposition of carbon in heating tube I3 if conversion temperature is obtained therein. Failure in supplying heat to the materials passing through the conversion tube I5 gently as described Will cause excessive deposition of coke in the conversion tube I5. The heating tube I3 should be made up of tubing having an inside diameter of not more than 4 inches, and preferably about 3 inches inside diameter, in order that the materials passing therethrough maybe heated in a minimum length of time. also n the heating tube I3 should be not more than 3500 feet in length, and preferably less than 2500 feet in length, for the same reason. The conversion tube I5 should preferably be as much as 3000 feet, and not less than 500 feet, in length.

While conversion may be obtained by this proc# ess when the materials passing through the heating tube I3 and the conversion tube I5 are held under a pressure as low. as atmospheric at the point P2, a greater degree of conversion will be obtained with the maintenance of higher pressures therein, even up to 2500 or 3500 pounds per square inch. I iind it desirable to maintain a minimum pressure in the conversion tube I5 at the point P2 of 2500 pounds per square inch I have three commercial units of the type described herein in operation at this time and. nd that the temperatures which may be most advantageously maintained at the points P1 and P2 vary with the particular kind of material being processed. I find it advantageous to maintain temperatures of approximately 850 F. and 840 F. at the points P1 and P2 respectively when con'- verting A. P. I. gravity fuel oil into gasoline under a pressure at the point P2 of approximately 300 pounds per square inch. I nd that a unit in which heavy gas oil is being converted to gasoline under a pressure of about 350 pounds per square inch at the point P2 operates most advantageously when temperatures of 885 F. and 875 F. are maintained at the points P1 and P2,

' respectively. I nd that a unit in which crude oil originally containing about percent. of gasoline is being converted to motor fuel under a pressure of aproximately 2600 pounds per square inch at the point P2 operates advantageously when a temperature approximating 875 F. and a temperature approximating 865 F. are maintained at the points P1 and P2 respectively. The fact that conversion under higher pressures results in higher yields of motor fuel is borne out 1 by the fact that conversion under the conditions described in the latter case results in the obtainance of a yield of approximately per cent of motor fuel'through a single operation while the yields of motor fuel obtained in the former cases described are only about 20 per cent per single operation.

'I'he converted materials which are delivered from the conversion tube I5 through the valve I6' may either be passed directly through a cooling coil to storage or they may be passed directly to any conventional equipment wherein they may be fractionated into desirable fractions which are separately collected, as described in application for patent for improvements in Process for manuf acturing motor fuels led by the present applicant February 12, 1932, Serial No. 592,614. One or more of the fractions produced by the process may be reprocessed in the same manner. y

For purposes of discussion, I have shown the furnaces I and 3 as entirely separate units and have discussed the heating tube I3 and conversion tube I5 as though they were two separate tubes; however, it is obvious that through the use of proper baille walls these two furnaces may for practical purposes be combined in a single furnace and the heating tube I3 and conversion tube. I5 may be a single tube equipped with an intermediate as well as a final temperaturefindicating device.

It will be found that the process disclosed herein has many advantages over conventional processes which are at present utilized for the purpose described, especially in view of the fact that my new process makes possible the obtainance of a high percentage yield per pass through f' the process of gasoline having a highantiknock rating. l

It should be understood that while I have described in detail one method of carrying out my new improvements I do not propose to limit myself to the details shown but propose to claim broadly all of the novel features which are inherent in these improvements.

I claim:

1. A process for the conversion oi nyurocarbon fluids, comprising flowing a hydrocarbon fluid with substantially undiminished veloc'ty through an elongated passageway of restricted cross sectional area, heating a portion of said passageway in one zone by hot gases of combustion and thereby cooiin-g said gases of combustion to a temperature nt more than F.above the maximum temperature to which the fluid is heated n passing through said passageway,- afterwards diverting a portion of the cooled gases and n thereby preventing the diverted portion of said gases from coming in contact with another substantail posterior portion of said passageway in a second zone, circulating another portion of said cooled gases of combustion over the last mentioned portion of the passageway and through the second zone without passing the circulated gases through the rst zone, and recirculating a part of the last mentioned portion of the cooled gases i through said lsecond zone and thereby main- 3' tainng said posterior portion of the passageway at an approximately constant temperature.

2. A process for `the conversion of hydrocarbon fluids, comprsing flowing a hydrocarbon fluid with substantially undiminished velocity through an elongated passageway of restricted cross sectional area, heating a portion of said passageway in one zone by hot gases of combustion and thereby cooling said gases of combustion to a temperature not more than 150 F. above the maximum temperature to whch the fluid is heated in that portion of said passageway, afterwards diverting a portion of the cooled gases of combustion by which said portion of said tube is heated, and thereby preventing the diverted portion of said gases of combustion from coming fn contact with another substantial posteriorv portion of .saidpassageway in a second zone, mixing air at 'atmospheric temperature with another portion of said cooled gases, and contacting the mixture of air and gases with said posterior portion of the passageway in the sec` ond zone without passing said mixture of .air and gases through the first zone, and thereby maintaining said posterior portion of the passageway approximately at the temperature of conversion. l

3. An apparatus for converting hydrocarbon fluids, comprising a heating chamber and a conversion chamber, a heating tube in the heating ing .the other end of the conversion chamber to the stack, a fourth breeching connecting the stack to the second breeching at a point between the rst breeching and the conversion chamber, means for introducing atmospheric air into the fourth breeching, a fan in the last mentioned breeching for causing a circulation of Vgases through a portion of the second breeching, the conversion chamber, third breeching, stack and fourth breeching, and means associated with some of said breechings for causing some of the gases of combustion from the rst breaching to travel to the stack without passing through the other breechings, and some of the gases of combustion from the rst breeching to travel through the second and third breechings, and for also causing some of the gases of combustion to be recirculated through the conversion chamber.

- 4. A process for converting hydrocarbon materials, comprising passing said materials through an elongated restricted passageway, contacting hot lgases of combustion with said passageway and thereby heating said materials which pass through the passageway to the temperature oflcfonversion and cooling said gases of combustion to a temperature not more than 150 F. above the maximum temperature to which the materials are heated in passage through said passageway, Passing said heated materials whichl have passed through said passageway through a second elongated restricted passageway with substantially undiminished velocity, contacting with said second passageway a portion only of the cooled gases of combustion, and introducing relatively cool gases into the last mentioned gases of combustion after the latter have passed the first mentioned passageway and before they have contacted with the second passageway and thereby maintaining said materia-1s at substantially the temperature of conversion.

5. A process for. converting hydrocarbon materials, comprising passing said materials through an elongated restricted passageway, contacting gases of combustion with said passageway and thereby heating said materials which pass through said passageway to the temperature of conversion and cooling said gases of combustion to a temperature not more than 150 F. above the maximum `temperature to which said materials are heated in passage through said passageway, passing said heated materials which have passed through said passageway through a second elongated restricted passageway with substantially undiminished velocity, contacting with said second passageway a portion only of the gases of combustion, and introducing relatively cool diluent gases into the last mentioned gases of combustion after the latter have passed the first passageway and before they have contacted with the second passageway and thereby preventing the temperature of said materials which are passed through said second passageway from being increased in passage therethrough more than 50 F.

6. A process for converting hydrocarbon materials, comprising passing said materials through a first elongated restricted passageway and heating said materials in passage therethrough to the temperature of conversion, contacting hot gases of combustion with said passageway and thereby cooling said gases of combustion to a temperature not more than-150 F. in excess of the maximum temperature to which said materials are heated in passing through said passageway, passing said materials which have been heated as described through a second elongated restricted passageway with substantially undiminished velocity, and further cooling a portion only of the combustion gases and afterwards contacting said portions only with said second passageway and thereby regulating the temperature at the inlet and outlet of said second passageway within a variation of less than 50 F. increase or decrease.

7 A process for converting hydrocarbon uids, comprising passing such a fluid through an elongated restricted passageway, flowing hot gases of combustion counter-current to said fluid and around and in heat exchange relation with the passageway while the uid is owing through at least a portion of said passageway and thereby heating said uid to the temperature of conversionwhile cooling said gases of combustion, passing said heated :duid with substantially undiminished velocity through a second elongated restricted passageway, contacting with said second passageway a portion only of said cooled gases of combustion, and introducing relatively cool gases into said combustion gases after they have passed the iirst passageway and before they have contacted the second passageway and thereby maintaining said iluid at substantially the temperature of conversion.

8. A process for converting hydrocarbon fluids, comprising passing such a fluid through an elongated restricted passageway, flowing hot gases of combustion 'counter-current to said fluid and around and in heat exchange relation with the passageway while the iiuid is flowing through at least a portion of said passageway, whereby said fluid is heated to the temperature of conversion and said gases of combustion are cooled, passing said heateduid with substantially undiminished velocity through a second elongated restricted passageway while flowing a portion only of the cooled gases of combustion concurrent thereto and in heat exchange relation therewith, and introducing relatively cool gases into the combustion gases after they have passed the rst passageway and before they "have contacted the second passageway and thereby maintaining the fluid at substantially said conversion temperature.

9. A process for converting hydrocarbon fluids, comprising passing such a uid successively through rst and second portions of an elongated restricted passageway, generating hot gases of combustion, passing said hot gases of combustion rst in contact with said iirst portion of said passageway, to thereby heat said fluid passing therethrough to atemperature of conversion, thereafter dividing said gases into two streams, diverting one of said streams and preventing it from contacting with said second portion of said second passageway, passing the remaining stream of gases of combustion in contact with said second portion of said passageway, cooling a part of said remaining stream of gases of combustion after it has contacted with said second portion of said passageway by introducing relatively cooled gases from an extraneous source into said part of said remaining stream of gases of combustion, and admxing the mixture of relatively cooled gases and gases of combustion with hot gases of combustion before said part of the remaining stream of gases of combustion contacts with the second portion of said second passageway.

MALCOLM. P. YOUKER.

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