US2048351A - Furnace for the pyrolytic treatment of hydrocarbon oils - Google Patents

Description

July 21, 1936. c. OFMELBERG FURNACE FOR THE PYROLYTIC TREATMENT OF HYDROCARBON OILS Filed June 25, .1934 2 Sheets-Sheet l INVENTOR Car/ 0. Me/erg BY .15: 4 am ATTORNEY y 21, c. o. MELBERG 2,048,351

I FURNAQE FOR THE PYROLYTIC TREATMENT OF HYDROCARBON OILS Filed June 23, 1954 2 Sheets-Sheet 2 ATTORNEY INVENTOR Gar/ 0. Ms/berg O O. O'OOGO OOOQOO.

Patented July 21, 1936v i i i FURNACE FOR THE PYROLYTIC TREAT- MENT F HYDROCARBON OILS Carl 0. Melberg, Ponca 'City, Okla., as signor to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Application June g3, 1934, Serial No. 732,051

, I'Claim. (Cl. 196-116) My invention relates to a furnace for the constructed and positioned that the tubes may pyrolytic treatment of hydrocarbon oils, and .be removed, cleaned, inspected, and/or replaced more particularly to a novel furnace constructhrough the headers by removing header covers. tion adapted to be used for cracking, heating, The furnace is fired at any suitable point and is and/or viscosity breaking of hydrocarbon oils. provided with a furnace gas duct arranged with 5 Theuse of pipe furnaces in which oil is flowed its axis coincident with the axis of the setting through a conduit or coil of comparatively small in order to provide for a straight line flow in cross sectional area externally heated by either the radiant heat section, preve t turbulenceradiant or convection heat has lately become In the u t y be p s t ned-convection tube prevalent in the pyrolytic treatment of hydrob s- The O l to be P ocessed may be char d 10 carbon oiIs, The processing and pyrolytic t0 the convection tube bank andthen through treatment ofhydrocarbon oils require comparaa the radiant tube bank. It may be charged to a tively high temperatures very much in excess section of the convection tube bank, then to the of those used in heating water to form steam. radiantly heated bank and then to another sec-.

The hydrocarbon oil is of such characterv tion'of the convection heat bank. The provision that, if heated to certain temperatures, it"tends s made, if d sir d. f r p v t n th ver eat to decompose to form lower boiling hydrocarbons ing o t e 011 being P o sed by injecting a and this decomposition is attended by deposition que ch 0 at a suitab e place in the heating coil. of carbon and tarry substances. Frequently, the In the a mpanying drawings which form part zo gases and lower boiling hydrocarbons which may of the instant Specification a d a e to be read in be formed by the pyrolytic treatment of hydro--' conjunction therewith. and 111 wh c ike re ercarbon oils form heavy polymers in the nature ehce numerals a u d to ndicate like parts in I of tar .or gums. The deposition of these subthe VariOuS w stances in the tubes of a pipe still render ire- Figure 1 is a sectional elevation of a furnace UNITED STATES, PATENT OFFICE quent cleaning necessary. Then, too, the high embodying one mode of carrying out my inven- 25 temperatures and pressures involved subject the tlon. tubes of the pipe still to severe stresses. This ur 2 1S a sectional p V ew ta en on a produces strains and permanent distortion. Frene 01 Figure quently, many hydrocarbon oils being processed Fi ure 3 is d view of a h a e u ed n contain sulphur compounds and/or mercaptans y g out my inv t of a corrosive nature. The attendant corrosion Fi ure 4 is a sectional, view taken along the results in the pitting and weakening of thetube e figure wallswith the result that failures are experienced. u e 5 S a ect ona e eva on 01 a furnace This necessitates the replacing of the tube which embedylflE another mode carrying out y I as has failed. invention. a v

One object of my invention is to provide a Figure 6 is a sectional view of a furace embodvnovel construction of a furnace for the pyrolytic ing still another mode of carrying out my intreatment of hydrocarbon oils which will enable vention. f the tubes ofthe furnace to be readily cleaned, Figure 7 is a diagrammatic sectional View.

.4 inspected, removed, and replaced. showing one mode of passing the ofl through a Another object of my invention is to provide furnace embodying one manner ofcarrying out a novel and emcient arrangement for pyrolytic my invention. treatment of hydrocarbon oils whereby they may More particularly referring now to the drawbe heated by radiant and convection heat in an ing p n a suitable foundation l I build a furefficient manner. nace setting having refractory side walls 2 sup Other and further objects of my invention will po ted. by a su tab e s eel s uctures. These appear from the following description. n is poly onal in cross section'asjcan readily be In general, my invention contemplates the seen by reference to Figure 2 in which it is she provision of a furnace setting in the form of a as a hexagon. It is to be understood, of course,

polygon, as for example pentagon, hexagon, hepthat any suitable number of sides, from five or 50 tagon, octagon, or the like. Thesetting is promore, may be used as desired. The greater the vided with reentrant portions at'the intersection number of sides the shorter the length ofthe of the sides. Short lengths of tubes extend adjatubes which are used in forming the pipe coil of 65 cent the respective sides through the reentrant the furnace. The sides are joined by reentrant portions. The tubes are connected byheaders, so portions 4, which are formed by keyed, rei'rac-y tory blocks 5, which are supported by steel channel columns 6, whose .shape can be readily seen by' reference to Figure 2. The short tube sections 1 extend through the reentrant portions adjacent the side walls of the furnace. Each tube length 1 has a slight pitch and has its ends extending into a header 8 as can readily be seen by reference to Figure 4. The header 8 consists of a body member having somewhat the formof an X, the angle being determined by the type of polygon, being used as the setting. If a hexagon is used as shown in Figure 2, the angle between the tube receiving; arms 3 of the header 8 would be 120". a

.In axial alignment with each of the tube receiving arms are extensions l8 provided with slots II in which are positioned the trunnions 12 of a yoke I3, which is provided with a screw threaded bore. Sealing plugs l4 are adapted to seat upon suitable seats which are provided with metal gaskets l5. Bolts l6 are adapted to be threaded through the screw threaded bores of yokes l3 to press plugs l4 against the seats. This construction can be readily seen by reference to Figures 3 and 4. The ends ofthe'tube 1 are expanded upon suitable seats l1,,- c arrled by tube receiving .por-

tions 9 of the header 8. The tubes 1, when connected by the headers 8, form a spiral coil composed of short lengths of straight pipe. The lengths of pipe may be'curved if desired. It is essential only thatthey be short so that they may be readily replaced and easily handled. The oil inlet to the pipe coil formed as just described is tends. Somewhere along one of the lowest passes,

as for example along tube length 22, a pipe connection may be made such as for example pipe 24 to which a quench oil maybe supplied to control the temperature of the oil being processed.

If a cracking operation is going on, over cracking or the temperature of the pyrolytic reaction may be controlled by controlling the quench oil through pipe 24, provided with a suitable valve.

The oil may be a low boiling oil, if desired. In the form shown in Figure 1, the fuel burners 25 are positioned in the floor of the furnace, air being supplied through ducts 28 which are provided with suitable registers 21. If desired, the space 28 may be connected to a blower system (not shown) or a system which supplies preheated air. The coil formed by the tube lengths '1 is positioned adjacent the walls of the furnace and the oil flowing through this coil will be heated mainly-by radiant heat. Thefurnace gases will be discharged through an outlet duct 23, which is positioned with its axis in axial alignment with the axis of the setting. This enables a straight line, flow of the furnace gases without turbulence and makes for a high velocity of flow.

Referringnow to Figure 5, which is a modificationof my invention, the setting is. a polygonal one as before, with the radiant heat coil arranged as befpre. The duct 29 extends through the setting and is provided at its upper portion with passages 28- through which the furnace gases flow I ontheir way to the stack 29'. Positioned within replacement may be done from without the-fur- 2,o4s,ss1

ed to be heated mainly by convection heat. The

32 to the coil formed of short lengths in the manner described, in' which it is heated mainly by radiant heat. The furnace is fired adjacent the bottom of the setting through burners 25, air

being provided through openings 26 supplied with air regulating registers 21. It is understood, of course, that the passages 28 may be made-adjacent the bottom of the' duct 21 and the furnace fired adjacent the top thereof, if desired. In the form shown in Figure 6, two sets of burners 25 v are shown having respective air registers 21. The furnace shown in Figure 6 may be fired either adjacent the top or the bottom or, if desired, both sets of burners may be employed. A tube bank 33 adapted to be heated mainly by radiant heat is positioned adjacent the ceiling of the setting shown in Figure 6. The tube bank may be used for superheating steam or may be connected in series with the coil formed of short lengths in the manner described. The duct 29-is positioned adjacent the bottom of the setting and the gases of combustion are adapted to heat tube banks 38 and 34 mainly by convection heat on their way to the stack 29'.- In the form shown in Figure 6, the oil is charged to the convection section 38, passes through transfer line 32 to the radiantly heated coil, from which it passes through transfer line 35 to bank 34, which is heated mainly by convection heat from which it passes .through outlet 36..

In the form shown in Figure '7, the oil is charged 35 to convection bank 38, from whichit passes to v the radiantly heated coil 33 through transfer line 32, then to a convection section 31, then through transfer line 38 'to the radiantly heated coil formed of short lengths in the manner described above, then through. transfer line 35 to convection section 34, to outlet 36. In the convection section 34, I may introduce a quench oil through pipe 24, controlled by valve 38. It is to be understood, of course, that this quench oil may be introduced at any suitable place in the travel oi. the oil, preferably in one of the later passes.

It will be seen that I have accomplished the objects of my invention. I have provided a furnace for the pyrolytic processing of hydrocarbon oils in which the oil may be eificiently heated by radiant and convection heat. The tubes 'of the furnace may be readily removed for replacement, may be cleaned easily and conveniently inspected. It is only necessary to remove two of the header plugs I 4 to clean or replace any of the tube lengths of the coil. The tube lengths are short and easily handled. The cleaning and nace settingso that it is not necessary t6 permit the furnace to cool-to such a degree that a man may enter the setting to do the work. The tube lengths are all of the same length so that a number of spare tubes may be precut and kept on hand. The advantages of this arrangement will be manifest.

It'will be understood that certain features and subcombinations are of utility and may be employed without reference to-other features and 78 subcombinations. This is contemplated by and is within the scope of my claim. It is further obvious that various changes may be made in details within the scope of my claim without departing from the spirit of my invention. It is therefore, 76

to be understood that my invention is not to be limited to the specific details shown and described.

vHaving thus described my invention, what I claim is: a In a furnace for the pyrolyticprocessing of hydrocarbon oils, a polygonal setting having live or more sides, the axis of said setting extending vertically, fuel-burning means within said setting, a coil through which the oil to be processed is adapted to flow, said coil comprising a plurality of substantially horizontally short lengths of tubing connected in series and positioned adjacent the side walls of said setting, a duct positioned within and extending axially of said setting. a flue, means providing communication between said duct and said flue whereby gases of combustion may pass from said setting through said duct, heat ex-' change means positioned in said duct and means for connecting said coil and said heat exchange means in series.

CARL 0; MEL-BERG.

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