US1873024A - Art of cracking and coking hydrocarbons - Google Patents

Description

Aug. 23, 1932. H. 1 PELZER ART OF CRACKING AND COKING HYDROCARBONS Filed Feb. 19, 1929 ,@M-,wom ATTORNEYS Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE HARRY Il. PELZER, 0F IGHLAND, INDIANA, ASSIGNOR TO SINCLAIR REFINING COM- y PANY, 0F NEW YORK, yNL Y., A CORPORATION OF MAINE ART 0F CRACKING AND COKING HYOROCARBONS Application led February 19, 1929. Serial No. 341,214.

This invention relates to improvements. in the combined vapor phase cracking of 011s, suchas gas oil or kerosene stocks, for the production of lower boiling oils, such as gasoline, and the coking of heavy oils, such'as crudes, topped crudes, flux oils, other res1dual oils and the like. The combined oper-v ation of the invention is of special application in -the handling of crude stocks or resldual stocks the handling of which usually involves difliculties due to corrosion or the products of which are unusually refractory with respect to the usual refining operations, because of the character or quantity of sulphur compounds in the stock, for example; but, as will appear, the invention is, 1n certain aspects, of more general application.

This invention is, in certain aspects, an iInprovement in the operations described in my application Serial No. 340,996, filed February 18, 1929, which has matured into Patent No. 1,831,719 issued November 10, 1931.

In carrying out this inventlon, as in carrying out the invention of Patent N o. 1,831,719 mentioned above, the hot vapor mixture from a vapor phase cracking operation, while still' at a high temperature, is passed in intimate contact with a liquid oil mixture to be reduced to coke in a receptacle adapted toreceive an accumulating charge of coke, this liquid oil mixture is coked in this receptacle by the heat of the hot vapor mixture from the vapor phase cracking operation, and the hot vapor mixture from this receptacle is discharged into and beneath the surface ofa liquid body of oil in another receptacle .in

which it is subj ected to a scrubbing operation.

vAccordimg to this'invention, the hot vapor mixture from the vapor phase cracking op eration is first passed through a irst and a second receptacle of a series in succession, a charge of oil being coked in the first receptacle and the hot vapor mixture from the first receptacle being subjected to a scrubbing operation in the second receptacle during this step in the operation, mixture from the vapor phase cracking operation is then passed through the second and a third receptacle of the series in succession, the preheated charge of oil being coked combined operation,

the hot vapor' in the second receptacle and the hot vapor mixture from the second receptacle being subjected to a scrubbing operation in the third receptacle during this step of the operation, the hot vapor mixture from the vapor phase cracking operation is then passed through the third and a succeeding receptacle of the series, as through the second and third, and so on, the coke product formed in each of the successive receptacles of the series being discharged when the coking operation in each receptacle is terminated. Oil to be reduced to coke may, with advantage, be supplied to the receptacle in Which the scrubbing operation is carried out during each ste of the combined operation. In each step o the the charge of oil in the receptacle through which the vapors first pass is reduced to coke by the heat of the hot vapor mixture from the vapor phase cracking or mixture from reed of entralned operation and the hot va this coking operation is material in the scrubbing thisl vapor mixture is subjected in thereceptacle through which the vapors next pass operation to which while the charge of oil in this last mentioned receptacle is at the same time preheated. In the next step of the combined operation this preheated charge of oil, including the constituents separated from the hot vapor mixture discharged from the coking operation in the preceding step, is reduced to coke, so that the combined operation, in accordance with this invention, is carried out without involving transfer of the charge of oil from the receptacle in which the scrubbing and preheating operation is carried out in each step of the combined operation to the preceding receptacle in which the cokin operation is carried out in the same step cfg the combined operation, the coking operation being transferred instead of the successive charges of oil to be reduced to coke. In this respect, the invention has several practical advantages; for example, hot oil pumps for transferring oil from the scrubbing receptacle to the coking receptacle are made unnecessary. In this respect, the invention is of special application in handling stocks containing substantial amounts of solids or semi-solids or of stocks A:which break up with the formationjof substantial amounts of solids or semi-solids at the temperatures prevailing in the scrubbing operation. The apparatus required is simplified in that the scrubbing operation is carried out in the same receptacles as the vcoking operation. The coke product formed in the coking operation can, 1n most cases, be more .thoroughly freed of volatile constituents without prejudice t Furthermore, the com ined operation of the invention, although carried out as a succession of steps, is, over all, made substantially continuous. v A

The invention will be further described vin connection with zthe accompanying drawing which illustrates, diagrammatically and conventionally, one form of apparatus, in elevation and partly in section with parts broken away, adapted for carrying out the invention, but it is intended and will be understood that the invention can be` carried out in other and diiferent forms of apparatus and that this further description is intended as exempliiication of the invention.

Referring `to the drawing, inJcarrying out the invention in the apparatus illustrated,

the hot vapor mixture from the vapor phase cracking operation carried out in the heater 1, without substantial cooling, is introduced, for example, into the rceptacle A in, which it is passedthrough a charge of oil to be reduce to coke and this charge of oil is thereby coked in the receptacle A while the hot vapor mixture from the receptacle A is subjected to a scrubbing operation in the receptacle B by bein discharged into and beneath the surface o a liquid body 'of oil maintained in the receptacle B this liquidbody of oil in the receptacle B being at the same time' preheated, when the charge of, oil in the receptacle -A has been reduced to coke the hot vapor mixture from'the vapory hase cracking operation carried out in the eater 1 is introduced into the receptacle '.B in which it is passed through thepreheated charge of oil therein and this charge of oil is thereby l coked in the vreceptacle B while the hot vapor mixture from the receptacle B is subjected to a scrubbing operation in the receptacle C by being discharged into and beneath the surface of ra liquid body of oil maintained in the receptacle C, this liquid body of oil inV the receptacle C being at the same time preheated',l and so on, the coke product formed 1n each-of the receptacles being discharged when the coking operation in each receptacle is terminated. Oil to be reduced to coke may be supplied, for example, to the receptacle B while the hot va or mixture from the operating economy.YY

of oil is being .reduced to coke. In the apn paratus illustrated, the vapor phase cracking operationV proper is carried out in the heater l comprising Vtwo groups of seriesconnected heating tubes arranged inthe heating flue of `a furnace 8, the oil owing first through one of the groups of heating -tubes countercurrent to the cooler heating gases and then through the other'group of heating tubes concurrent to the hotter heat.

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ing gases, a fan 9 for circulating the heating gases through the heating flue, ducts 10 provided withdampers as shown for recirculating part of the heating gases through the heating iue and for discharging part of the heating gases to the stack 11, a fan 12 and a preheater 13 arranged in the stack 11 for supplying preheated airfor combustion to the frebox 14 of the furnace 8. Oil is supplied to the heater 1 through connection 15 and the-hot oil products of the vapor phase cracking operation carried out therein are discharged through connection I6.`

`The coking operation and the scrubbing and preheating operationare carried out inv the series of receptacles A, B,- C and D. This series ofreceptacles may' include three, four or more receptacles. These receptacles may,

for' example, \be horizontal or vertical drums with suitable means, removable heads or the like, for the discharge `of the coke product formed therein. In the apparatus illustrated, the hot vapor mixture discharged from the scrubbing and' preheating operation of the combined operation of theinvention is dis-14 charged through connection 7 to suitable condensing or fractionatingand condensing or 1 other recovery apparatus,for example, to re.- covery apparatus such as that described in application Serial No. 198,621 `mentioned a ove, and that recovery apparatus may be operated, in conjunction with the carrying o ut of this invention, as described in application Serial No. 198,621 mentionedabove'.V In the apparatus illustrated, by'y means of conf nections 20, 21, 22 and 23, connections 24, 25,

26 and 27 Yand connections 28, 29, 30 and 31 hot vapor mixture `discharged from the vapor phase cracking operation through connection 16 maybe passed eitherpthrough receptacles and B. in succession, or receptacles B and -C 1n successlon, or receptacles C and'D in and the valves shown in these connections, the' l succession, or receptacles D and A in succession, providing fol-'the carrying out of the. in-

vention in these successive' pairs of receptacles. By-pass connection 32 is provided to permit the hot vapor mixture from thevapor phase cracking operation to be discharged directly from connection 16 through connection 7. The oil to be reduced to coke is supplied to the receptable in which the scrubbing operation is carried out, in each step of the combined operation, through connection 19 by means of the valved branches illustrated.

Connection 17 is provided for supplying steam, through the valved branches shown, to the lower ends of the receptacles A, B, C and D and condenser-18 is provided for use when steaming out these receptacles.

In carrying out the invention in the apparatus illustra-ted, in each step of the combined operation an initial charge of oil less than the total charge of 'oil to be reduced to cokel in the next step of the combined operation may be supplied to the receptacle in which the hot vapor mixture from thereceptacle in which the coking is carried out is subjected to a scrubbing operation and additional amounts of this oil supplied to this receptacle during the scrubbing operation to bring this charge of oil to the desired total by the time it is to be subjected to the coking operation in the next step of the combined operation.

In the apparatus illustrated, receptacle A,

B, C and D, the vapor lines between them,

and connections 16 and 7, are, with lagged or` thermally insulated.

A specilic example of an operation emadvantage,

. bodying the invention as carried out in apparatus of the type illustrated will further exemplify the invention: Fires are started and the heating furnace Sis brought to operating temperatures while circulating steam through the heater l and, for example, receptacle A. The initial charge of oil to be reduced to coke in, for example, receptacle A may be separately preheated and supplied to this receptacle orit may be preheated by circulation through the heater 1 While the heating furnace 8 is being brought to operating temperatures. When the heating furnace 8 has been brought to operating temperatures, the circulation of gas oil or other stock to be subjected to the vapor phase cracking operation through the heater 1 is started. This stock may bea raw gas oil, for example, or an intermediate condensate separated from the vapors discharged through connection v7, vfor example, or a mixture of the two, for example. By the time the circulation of the stock to be sub'- jected to the vapor phase cracking operation through the heater 1 is started, the receptacle B is filled about one-third full, more or less, with the stock to be reduced to coke, and when the circulation of the stock to be subjected to the vapor phase cracking operation through the heater 1 is started the hot vapor mixture from the vapor phase cracking operation is discharged through the charge of oil to be reduced to coke in the receptacle A and the hot vapor mixture from receptacle A is subjected to a scrubbing operation by 4 being discharged through a liquid body of oil maintained in'receptacle B, the hot vapor mixture from receptacle B being discharged through connection 7. During this step of the operation, the stock to be reduced to coke is supplied to the receptacle B at a rate such that this receptacle is approximately full at the end of this step of the operation. When the charge of oil in receptacleA has beenreduced to coke and'when a suflicient charge of oil has accumulated in receptacle B to be subjected to the coking operation, the hot vapor mixture from receptacle B is passed through a liquid body of oil in receptacle() j to which van initial charge of oil has been supplied as previously described in connection with the operation of receptacle B in the preceding step of the combined op-eration. The hot vapor mixture from the vapor phase cracking operation may be passed through `the charge of coke in the receptacle A for some time after the coking operation in receptacle B has been terminated, for example, to assist in stripping this charge of coke of volatile matter. When the charge of coke in receptacle A lis suificiently free of volatile matter, the hot .vapor mixture from the vapor phase cracking operation is discharged directly into the receptacle B, the receptacle A is' steamed out through condenser LS and at the termination of the steaming out operation the charge of coke in the receptacle A is removed and this receptacle is cleaned to be ready to receive a charge of oil for carrying out the scrubbing .operation during the further step of the conrbined operation in which a charge of oil is being reduced to coke in the receptacle D. In apparatus such as that illustrated comprising four coking, and scrubbing and preheating, receptacles,- each receptacle may, as an example of a convenient and satisfactory operating cycle, be operated on the following aov schedule, eight hours on the combined scrubl bing and preheating operation, eight hours on the coking operation, eight hours on stripping the coke of volatile matter and steaming out, and eight hours on cleaning. In carrying out the combined operation of the invention, the hot vapor mixture from the vapor phase cracking operation may be discharged through connection 16 at a temperature, for example, in the neighborhood of 1100-1120 F., and the hot vapor mixture` from the combined operation may be discharged through connection 7 at a temperature in the neighborhood of G50-950 F Asmentioned above, this invention is of special application in handling stocks containing substantial amounts of solids or semi-solids. The invention is useful, forextar, neutralized acid sludges, andthe like.

ample, in reducing to" coke stocks such as lcrude oils or reduced crude oils including i ythereby preheating said liquid body of 011,

substantial amounts of admixedsolid treating agents, lime for example, or such as tank settlings, semi fluid niixtures of coke andv I claim: r p

1. In a combined vapor phase cracking and coking operation, the improvement which comprises vaporizing and cracking oil in the vapor hase, then passing the hot vapor mixture rom the vapor phase cracking operation through a first and a second receptacle of ka series in succession, reducing a charge of oil tocoke in the first receptacle and subjecting the hot vapor mixture from the rst receptacle to a scrubbing operation in the vsecond receptacle by discharging it into and beneath the surface of a liquid body of oil therein While thereby preheating. said liquid body of oil, then passing the hot vapor mixture from the vapor phase cracking by discharging it `into and beneath the surface of a liquid body of oil therein while and 4dlscharging coke from the first receptacle, supplylng-oil to be reduced to coke to the third receptacle during this step of the combined operation, then `passing the hot vapor mixture from the vapor phase cracking operation through the third and a succeeding receptacle of the series, as through the second and third, suplying oil to be reduced to coke;to said succeeding receptacle of -t-he series during this step of the combined operation,--and dlscharging coke from the second resceptacle, and so on, retaining the charge of oil in the receptacle in which the'scrubbing and preheating operation is carried out in each step ofthe combined operation in that receptacle.

HARRY L. ELZER.

- operation through the second and a third re- .i

ceptacle of the series in succession, reducing the preheated charge of oilto coke in the sec-- ond receptacle and subjecting the hot vapor mixture from the second receptacle Cto a scrubbing operation in the third receptacle f by discharging it into and beneath the surface of a 'liquid body of oil therein while thereby prehea'ting said liquid body of oil, and discharging coke "from the first receptacle, then passing the hot vapor mixture from the vapor phase crackingroperation through the third anda succeeding receptacle of the series, as through the second and third, and discharging coke from the second receptacle, and so on, retaining the char e of oil in the receptacle in which the scrub ing In testimony whereof I aix m signature.

and preheating operation is carried out in each step of the combined operation in that receptacle.

42. In a combined vapor phase cracking-and coking operation, the improvement which comprises vaporizingand cracking oil in the ture from the vapor phase cracking operation through a first and a second receptacle of a series in succession, reducing a char e of oil tocoke in the first receptacle and su jecting mixture from the vapor phase cracklng operation through the second and a third receptacle of the series in succession, reducing the preheated charge .of oil to coke in the second receptacle and subjecting the hot vapor mixture from the second receptacle to al scrubbing. operation in the third receptacle vapor phase, then passing the hot vapor mix-

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