US2140278A - Treatment of hydrocarbon oils - Google Patents

Description

Dec. 13, 1938. M w B RNE 2,140,278

TREATMENT OF HYDROCARBON OILS Original Fi Dec. 1'7, 1932 INVENTOR MARION W BARNES BY F QZQJQ ATTOR Y Patented Dec. 13,1938 2 140 27 UNITED sTATEs PATENT OFFICE TREATDIENT OF HYDROCARBON OILS Marion W. Barnes, Chicago, 11]., assignor to Uni versal Oil Products Company, Chicago, 111., a corporation of Delaware Application December 17, 1932, Serial No. 647,764 Renewed March 18, 1936 Claims. ('01. 122-356) This invention relates to the heating of hydrobustion and radiant heating sections of the furcarbon oils, particularly to the high temperatures nace but provision is made for controlling the required for their conversion, and more specifirelative quantities of combustion gases passed cally embodies improvements to the type of furthrough the convection section of each heating 5 nace wherein separate streams of the same oil coil so that heating conditions are independently 5 are heated under the same or similar conditions controlled in the convection sections as well as in or wherein separate streams of different oils are the radiant section of each coil.' heated under different conditions. The attached diagrammatic drawing and the With theemand for ever increasing capacity following description thereof will serve to more of individu 1 cracking units from year to year, it clearly illustrate the features and advantages of 10 v has in many cases become advantageous in dethe present invention. Figure 1 ofthe drawing S gning furnaces for the high charging rates to is a sectional elevation of the furnace and Figsplit the total oil supplied to the heating coil into ure 2 is a sectional plan View of the same structwo or more streams, each of which is heated in ture. Figure 1 may be considered as taken along y 15 separate sections of a heating coil within a single a vertical plaza indicated by the line l in Fig- 15 furnace, under conditions as nearly identical as ure Z-and ure 2 may be considered as taken it is possible to maintain. Adeparture from this along a hori ntal plane indicated by the line practice, which is apparently gaining favor, com- 2-2 in Figure 1. prises subjecting the raw oil charging stockin The main furnace structure comprises side one portion of the heating coil to different conwalls I and I, end walls 2 and 2', a roof 3 and 20 ditions' of treatment than that afi'orded insuffia floor 4. It will be noted in the, drawing that ciently converted intermediate products of the the furnace is symmetrical on opposite sides of operation (reflux condensate) which are returned a, plane throug t e Center f the furnace, indito another portion of the heating coil. The latcated by line C in the drawing, the left hand ter practice is sometimes varied by separating the side having a combustion zone 5, a radiant heat- 26. raw oil or refiuiiv condensate, or both, into low ing zone 6 and a convection heating zone .Twhile boiling and high boiling fractions which are subthe right hand side of the furnace has similar jected to different heating conditions in separate zones 5', 6' and i, respectively. A perforated portions of a heating coil within a single furnace arch 8 separates combustion zone 5 from radiant structure. In furnaces of this general type, difli-' heating zone-6 while similar perforated arch 8 3i) culty has heretofore been encountered in indeseparates combustion zone 5' from radiant heatpendently controlling the heating conditions in mg Zo e 6'. A bridge Wall 9 Separates C the different portions of the heating coil to which tion zone 5 from convection heating zone I and different streams of the same or different hydroa similar bridgewall 9' separates combustion carbon oils are supplied. zone 5 from convection heating zone 1'. A per- 35 T e present invention embodies a, furnace of forated arch Ill separates bothradiant heating improved design particularly adapted to, the o es, 6 d 6' f e Corresponding COIlVeCf treatment of separate streams of the same or t o heating Zones 7 and and a Dartitidh ll different hydrocarbon oils wherein the heating separates e convection heating, Zones 1 and 1- 40 conditions to which the separate streams are sub- As indicated more clearly in the p n V w 40 jected are independently controlled so that each (Figure 2), the combustion zone 5 compr ses a stream may be subjected to the same or to differpluralityf s parat y fir d compartments t cut heating conditions, as required by the process. utility of which will be later described. Com- In the preferred form of the apparatus of the Dart e s H are Separated by walls and are present invention the furnace structure is bl.- supplied with combustibles in the form of oil, 45 laterally symmetrical, in design and a heating gas p ve Solid u preferablyfmixed coil is disposed within each symmetrical section "with air, steam or other suitable combustionsupof the furnace. Each heating coil is divided into porting and vaporizing medium, through burners radiant and convection sections. Each symmet- M of any suitable form, additional air being sunrical section of the furnace is independently fired plied, when desired, through ducts' [5 controlled '50 so that the heating conditions in the radiant secby dampers l 6. The combustibles are supplied tion of each coil are independently controlled. to the combustion zcne through firing tunnels I! The convection sections of the separate heating which as here illustrated, may be of the Vcnturi coils are adjacent and are heated by the comthroat type in order to impart a high velocity to mingled combustion gases from the separate comthe combustibles, insuring their turbulence and r intimate mixture in the combustion zone to promote complete combustion of the fuel. This is augmented by a slanting target |8 having an irregular surface which assumes incandescence upon heating and assists complete combustion of the fuel. Auxiliary air may be supplied to combustion zone 5 through tunnels I9 regulated by dampers 20, located beneath combustion tunnels Prime numbers corresponding to the numbers above given indicate similar parts on the opposite side of the furnace.

Superimposed rows of horizontally disposed tubes comprise convection bank 2 I, located with in' the convection heating section I and a similar bank 2| of convection heating tubes is located in the convection heating zone I. A row 22 of horizontally disposed tubes extending along the side wall and roof of radiant heating zone 6 forms the radiant heating bank of the left hand side of the furnace and a similar bank of tubes 22' is located along the side wall and roof ofv convection heating zone 6' on the right hand side of the furnace. The tubes of both the radiant and convection banks extend between the end Walls 2 and 2' of the furnace andthe ends of adjacent tubes, as well as adjacent rows of tubes,

I are connected in series by means of suitable headers or return bends, not illustrated in the draw- In the case here illustrated, one stream of oil enters the bottom row of tubes in bank 2| through line 23 and valve 24, passing in series through adjacent tubes and upward through adjacent superimposed rows of tubes to the top row in bank 2|, from which it is discharged through line 25, located outside the heating zone, into the bottom tube of that portion of the radiant bank 22 located along side wall I, passing upward through adjacent tubes in this bank and then through the tubes of the same bank located along the roof of the furnace, being finally discharged from the heating coil through line 26. In a similar manner another stream of oil which, as already indicated,

- may be the same or a different type of oil than that supplied to the furnace through line 23, may be supplied through line 23' and valve 24', flowing through the tubes of convection heating bank 2| through lines 25 and the tubes of radiant bank 22' in the same manner as the oil flowing through the similar bank 2|, line 25 and bank 22, as already described, being finally discharged from the furnace through line 26'. Valves 24 and 24 in lines 23 and 23' respectively, serve as a means of controlling the quantity of oil supplied to each heating coil. It will be understood that the direction as well as the path of flow through the heating coils may be varied from that described and illustrated, without departing from the scope of the. present invention. It is also within the scope of the invention to employ two or more rows of tubes in the radiant banks instead of the single row shown in the drawing, in

which case the rows adjacent the walls of the furnace will be partially shielded by the outer row so that a somewhat lower rate of heating will obtain in the inner rows of the radiant banks.

By employing different directions and/or paths of flow through the heating coils'different heating curves of any desired type may be obtained and the same or a different type of heating curve may be employed for the two streams of oil supplied to the furnace, to suit requirements. Preferably, when the same type of oil is supplied to both heating coils, the path and direction of flow through both coils, well as the quantity of oil supplied to each coil and the heating conditions employed on opposite sides of the furnace, are the same so that the same heating curve is obtained and each stream of oil is subjected to approximately identical conditions of treatment. However, in the improved design of furnace embodied in the present invention, variations may be made in the heating conditions employed'on opposite sides of the furnace, as will be later more fully described, to compensate for any variation in the quantity of oil supplied to each heating coil while the conditions remain the same in the two heating coils. When oils of different characteristics are supplied to the two heating coils different methods of treatment are preferably employed for the two streams which may be accomplished by changing any or all of the variables on opposite sides of the furnace, such as firing conditions on opposite sides of the furnace, the direction or path of flow of oil through the heating coils or the rate of feed to the heating coils.

The oil flowing through radiant heating banks 22 and 22' is heated, primarily, by radiant heat from the combustion gases and from the walls of the furnace. Perforated arches 8 and 8' not only serve to distribute the combustion gases more evenly through the radiant heating zones 6 and 6' but are heated to a radiating temperature thereby serving as a radiating surface for the transmission of heat to the tubes of banks 22 and 22. Due to the division of combustion zones 5 and 5' into a multiplicity of compartments l2 and I2 and the provision already described for supplying combustibles separately to each compartment, variations may be made in the firing conditions in each compartment tocompensate for any unequal draft conditions within the furnace and maintain substantially uniform heating conditions along the length of the radiant tube banks. heating zones. 6 and 6 downward through the convection heating zones 1 and I. ,The extensions of bridge walls 9 and 9' above arches 8 and 8', as illustrated in the drawing, serve to prevent short-circuiting of the combustion gases from the combustion zone to the convection heating zonesand perforated arch l0 serves to uniformly disand pass from the convection heating banks around dampers 21 and 21 which serve as a means of regulating the relative quantity of combustion gases passing through convection heating zones 1 and 1' so that their velocity around the tubes and consequently the rate of heating may be controlled in each of the tube banks 2| and 2|. The spent combustion gases are discharged from the furnace through flue 28, regulated by damper 29 to a suitable stack, not shown. Preferably, however, a portion of the combustion gases having passed through the convection heating zones pass through ducts 30 and 30 to the flue gas recirculating fans 3| and 3| which are motivated by any'suitable means, not illustrated in the drawing, and serve to reclrculate the gases through ducts 32, 32', 32 and 32" to tunnels 33 and 33 from which they may pass through openings 34 and 34' in the floor of the furnace into the combustion zones 5 and 5. Dampers 35 and 35' in openings 34 and 34', respectively, serve to regulate thev quantity of recirculated gases sup- The combustion gases pass from radiant plied to each of the compartments i2 and I2 of the combustion zones, thereby serving as an additional means of regulating the temperature in each compartment of the combustion zones. By discharging the recirculated flue gases into the combustion zones at an angle, as provided by the slanted openings 3% and 3 5', as illustrated in the drawing, turbulence and thorough mixing of the recirculated gases with the fresh products of combustion is insured although this is, of course, not a limiting feature of the invention.

I claim as my invention:

1. In a furnace for simultaneously heating J separate streams of fluid, means dividing the 15 furnace into a convection compartment and a pair of radiant heating compartments, a pair of heating coils, each comprising a plurality of series connected tubes, disposed in said convection compartment a plurality of series connected heatment.

2-. In a furnace for simultaneously heating separate streams of fluid, means dividing the furnace into a central compartment and outer compartments on opposite sides of the central compartment, a pair of heating coils each comprising a plurality of series connected tubes, in said central compartment, a plurality of series connected heating tubes in one of the outer compartments and connected in series with one of said coils, additional series connected heating tubes in the other outer compartment and connected in series with the other of said coils, and means for independently regulating the quantity of combustion gases passed over each of said coils in the central compartment, means for passing combustion gases from both said outer compartments through said central compartment.

3. In a furnace, the combination of means dividing the furnace into a central compartment and a pair of outer compartments, an apertured heat-radiant wall dividing each of the outer compartments into a heating section and a combus tion section, means for generating combustion gases in said combustion sections to flow through said walls into the heating sections, a series of heating tubes in each of the heating sections and a pair of heating coils in said central compartment, one of said coils being connected to the tubes in one of said heating sections and the other of said coils being connected to the tubes in the other heating section, means for passing combustion gases from both' said heating sections through said central compartment, and means for independently regulating the quantity of combustion gases passed over each of said coils in the central compartment.

4. A heating apparatus comprising a furnace having a pair of combustion and heating compartments and a convection heating compartment, means for passing combustion gases from both said combustion compartments through the convection compartment, a fluid conduit comprising serially connected heating tubes disposed in one of the combustion compartments and in the convection compartment, a second. fluid conduit comprising serially connected heating tubes disposed in' the other of said combustion compartments and in the convection compartment, and means for independently regulating the quantity of combustion gases passed over the tubes of each of said conduits disposed in the convection compartment.

5. A heating apparatus comprising a furnace having a pair of outer combustion and heating compartments and a central heating compartment, means for passing combustion gases from both said outer compartments through the central compartment, a fluid conduit comprising serially connected heating tubes disposed in one of the outer compartments and. in the central compartment, and a second fluid conduit comprising serially connected heating tubes disposed in the other of said outer compartments and in the central compartment, and means for independently regulating the quantity of combustion gases passed over the tubes of each of said conduits disposed in the central compartment.

MARION W. BARNES

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