US2687992A

US2687992A - Conversion of heavy petroleums in a fluidized coking operation

Info

Publication number: US2687992A
Application number: US101842A
Authority: US
Inventors: Frederick W Leffer
Original assignee: Universal Oil Products Co
Current assignee: Universal Oil Products Co
Priority date: 1949-06-28
Filing date: 1949-06-28
Publication date: 1954-08-31
Anticipated expiration: 1971-08-31

Description

Patented Aug. 31, 1954 UNITED STATES OFFICE CONVERSION OF HEAVY PETROLEUMS IN A i FLUIDIZED COKING OPERATION Application June 28, 1949, Serial No. 101,842

11 Claims. l

This invention relates to an improved process and apparatus for effecting the conversion of heavy petroleums in a uidized coking operation. More particularly the improved operation relates to the conversion of heavy petroleum stocks, such as topped crude, reduced crude, bunker C fuel and the like, to form more desirable lower boiling products and additional coke by utilizing a compact unitary apparatus and a continuous flow of coke particles, with luidization and heating of the circulating coke particles being provided primarily by hot combustion gases.

lThe older and most common methods of coking oils involved the heating of an oil stream to a temperature permitting ash distillation to dryness within a separating and coking chamber, wherein vapors were removed and a solid coherent mass of coke deposit allowed to build up on the walls thereof. This type of operation has been rather unsatisfactory; two or more coke chambers were required to effect a continuous operation, and troublesome methods were required for breaking up the mass of coke and removing it from the chambers. More recently, various fluidized types of coking operations have been developed, utilizing either a single chamber, wherein the oil stream contacts fluidized coke particles and oxidizing gases for the generation of heat by the partial combustion of a portion of the carbonaceous materials within the coking chamber, or

alternately, utilizing two separate zones, one providing a coking zone and the other a combustion and heating zone. In the latter type of operation the charge stream contacts the heated coke particles in a coking and conversion zone and resulting particles are passed to a burning and combustion zone wherein a portion of the coke particles are burned to effect the heating of another portion of the coke particles which is then transferred to the coking zone. However, in general, these operations involve the burning and oxidizing of at least a portion of the coke material which is produced within the operation, to in turn effect a heating of the coke particles which are to be present in the coking zone to aid in effecting the conversion and coking of the charge stream.

It is a principal object of the present invention to provide a continuous iiuidized coking operation wherein the coke particles are heated by hot combustion gases produced externally of the coking zone, substantially without any burning or oxidizing of coke particles during the operation.

It is a further object of the present invention to provide a fluidized coking operation wherein the endothermic heat for the conversion of the hydrocarbon charge stream is supplied by means of hot combustion gases which in turn are generated separately from the coking step by the oxidation of a portion of the product vapors obtained by the conversion and coking reactions.

It is a still further object of the invention to effect an improved flow in a compact unitary apparatus such that a concurrent flow of the charge stream and coke particles is maintained within a coking zone and a countercurrent flow of resulting coke particles is maintained in a heating and drying zone adjacent to and in heat exchange relationship with the coking zone.

It is still another object of the present invention to provide for the preheating of the hydrocarbon charge stream and to utilize high temperature combustion gases as a gaseous medium for atomizing or dispersing the hydrocarbon stream upwardly into the coking zone such that the oil is given a high speed coking temperature immediately prior to contacting the fluidized coke particles.

A further object of the invention resides in providing a compact unitary apparatus for carrying out the present process in a particularly advantageous and thermally effective manner.

Additional objects and advantages of the process will be noted hereinafter or will be apparent from the subsequent description relating tothe present continuous method of operation and apparatus and iiow shown in the accompanying drawing.

Broadly, the present invention provides an improved method for converting a relatively heavy hydrocarbon charge stream into more desirable lower boiling products and coke particles which comprises dispersing the hydrocarbon charge stream upwardly into a confined coking zone concurrently with a hot gaseous heat-carrying medium and heated fluidized coke particles, effecting a high temperature Contact between the particles and the dispersed hydrocarbon charge stream whereby to form vaporous distillation and conversion products and additional coke, discharging resulting coke particles from the upper portion of the coking zone and passing them downwardly through a confined drying zone contiguous the coking zone, passing a hot gaseous non-oxidizing drying medium into and upwardly through the drying zone and therein maintaining the coke particles in a fluidized phase by the ascending drying medium, introducing a portion of the resulting heated and dried coke particles from the lower portion of the drying zone upwardly into and concurrently with said gaseous heat-carrying medium through the coldng zone and into contact therein with the hydrocarbon charge stream, discharging the vaporous and gaseous products from the upper portions of both the coking and drying zones, and withdrawing excess coke particles from the lower portion of the drying zone.

Somewhat more specifically, it is a feature of the present process to utilize hot combustion gases as the fluidizing medium within the coking zone, as well as hot combustion gases for the heating and drying of the resulting coke particles within the drying zone, which is maintained adjacent to and in heat exchange relationship with the coking zone. A portion of the gas and vapor products withdrawn from the upper portions of the contacting zones (the coking zone and the drying zone) is passed to a separate confined combustion gas generating zone wherein air is introduced and hot combustion gases are generated for subsequent passage to each of the contacting zones of the unit. By this type of operation, the coking reaction is performed in a substantially non-oxiding atmosphere and all coke which is formed within the coking zone is maintained in and subsequently withdrawn from the unit with substantially little or no loss and in any event without any substantial combustion thereof. It is of course, a necessary feature of the present fluidized operation to recirculate a portion of the coke particles to the lower end of the colzing and conversion zone to provide nuclei and a hot fluidized mass of particles for contacting the hydrocarbon stream which 'm continuously dispersed or atomized into the coking zone.

Another 'feature of the present process, providing a preferred operation, is the use of a separate stream cf hot combustion gases to atomize or spray and disperse the hydrocarbon stream upwardly into the fluidized bed of particles. The atomizing gas stream is supplied at a high ternperature of the order of 1040 F. to 1500" F. whereby to impart a high speed coking temperature to the oil stream immediately upon its entrance to the coking zone so that the oil substantially at the moment of its dispersal attains abou the same temperature as the temperature of the coke particles being injected upwardly into the colring zone. Also, hot combustion gases are preferably supplied from the combustion gas generator to jet, or inject, the recirculated particles to the lower portion of the ccking zone and the temperature of the combustion gas streams is correlated with the rate of their supply to the coking zone so that a fiuidized bed of coke particles within the coking zone is maintained and the dispersed oil droplets are converted into vaporous and gaseous conversion products and discrete coke particles substantially free from tarry binding material during the continuous concurrent fiow of the fluid materials and fluidized coke particles upwardly through the coking zone. Thus, there are two combustion gas streams entering the lower portion of the cosing zone, the atoinizing or spraying stream and the particle injecting and fiuidizing stream, and the relative quantities of gas, as well as the temperatures of the streams. must be regulated and controlled with respect to the size of the coifling zone and the quantity of heavy oil charge, to effect the desired conversion of the oil spray to coke and more valuable lower boiling products substantially within the confines of the coking zone.

In a preferred arrangement of the contacting zones, the coking and conversion zone is main,-

tained within a cylindrical confined section centrally disposed within and spaced from an enclosing chamber and has open upper and lower ends such that coke particles which have contacted the hydrocarbon charge stream and which are formed in the process may settle downwardly around the coking zone Within the conned chamber. Thus, the resulting coke particles are maintained in an annular shaped bed which descends contiguous to and in heat exchange relationship with the coking and conversion zone. I-Ict combustion gases, as hereinbefore mentioned, are passed upwardly through this descending bed of coke particles to effect a heating and drying thereof prior to their withdrawal or recycle to the colring zone. The desired portion of coke particles required in the coking zone is injected or jetted into the lower portion of the coking zone with the aid of a separate hot combustion gas stream, while the excess coize particles lare discharged from the lower end of the heating and drying zone in a continuous descending stream. It is still another feature of the present invention to pass the net product coke particles substantially by gravity flow from the heating and drying zone into a quenching zone which is maintained separate from and below the latter, so that heat may be recovered from the particles, and the coke particles themselves may be removed from the unit in a slurried stream.

Preferably, water is introduced into the lower portion of the quenching zone and steam generated therein for use in the contacting zones or other portions of the plant. Such steam may be used, for example to strip the coke particles within the lower portion of the heating and drying zone prior to their passing into the quenching zone. However. it is not intended to limit the present invention to the use of water only as a quenching medium within the quenching and cooling zone, for a hydrocarbon distillate stream may be utilized to quench the coke and to provide a hydrocarbon slurry stream suitable for fuel or other uses.

lie gasiform mixture Which is discharged from the upper portion of the coking and conversion zone is passed to a suitable separating and fractionating equipment, except for that portion of the product stream which, in a preferred mode of practicing the present process is passed substantially without cooling to the combustion zone for the generation of the hot combustion gas required in the contacting zones as hereinbefore described. The vaporous product stream prior to its fractionation and separation may be quenched by a water stream or other suitable iuid medium in order to reduce its temperature to a sufficiently low level for fractionation and the recovery of gaseous and low boiling liquid fractions. In a prefererd mode of operation, however, the hydrocarbon charge stream is utilized as the quenching medium for the vaporous product stream to be fractionated so that the charge stream itself is preheated prior to its being introduced into the coking and conversion zone. For example, when obtaining the vaporous product stream from the coking and conversion zones at a temperature of the order of l to 1200 F. the portion of this stream to be fractionated is quenched with the incoming cool charge stream to impart to the latter a temperature of about 600 F. or such other temperature at which substantially none of the oil charge is vaporized and carried to subsequent fractionation in the vapors and gases remaining uncondensed after the quenching step. The resulting preheated oil charge including high boiling components of the uid product stream from the coking operation may be supplied directly to the spraying device within the coking zone, or it may be further preheated in a separate heater to a more elevated temperature of the order of 'W5-900 F. under non-Coking conditions before being introduced through the spraying device to the coking zone.

Reference to the accompanying drawing and the following description thereof will serve to clarify the improved operation and now of the present invention, as well as to point out additional features and advantages obtained by this fluidized cokng embodiment.

Referring now to the accompanying drawing, there is shown one specic embodiment of the present operation within one desirable form of apparatus arrangement. The vertically disposed chamber has an upper enlarged portion to provide a particle separating zone 2, and an internal cylindrically shaped partition or open-ended chamber 3 which in turn provides a coking zone il. The internal chamber 3 is spaced from the wall of the external chamber I in a manner to provide an annular shaped drying zone 5 for the heating and drying of resulting coke particles. In operation, a continuously moving fluidized bed of coke particles is maintained within the coking zone il, with iiuidizing mediums being supplied to maintain the continuous upward movement and overflow of coke particles from the inner zone into the separating zone 2, and subsequently downwardly through the drying zone 5, which encompasses and surrounds the inner coking zone il.

The preheated heavy oil charge stream is introduced to the lower portion of the coking zone by means of line having valve '1, and as hereinbefore noted, the stream is preferably sprayed or dispersed upwardly into the zone by means of a hot combustion gas stream which is supplied to an atomizer or dispersing device 8 by means of line 9 having control valve I0. Preferably, the hydrocarbon stream is preheated to a suitable temperature up to about 900 F. and most advantageously of the order of 800 to 850 F. under substantially non-coking conditions, while the hot combustion gas stream is supplied at a temperature generally above 1000" F. and up to about 1500o F. and preferably at about 1150-1400" F., in order that the oil stream be dispersed at an effective coking temperature into the ascending luidized bed. whereby to form additional finely divided coke particles or additional coke on the coke nuclei which are maintained in the uidized bed within the zone d. A concurrent iluidized flow is maintained within the coking Zone 4l and the operation is maintained in a continuous manner with particles being passed into the separating zone 2 from the open upper end of the coking zone. The resulting coke particles are thus subsequently allowed to descend in a hindered settling flow around the coking zone 4 and chamber wall L?, thus providing a continuous descending nuidized bed of particles within the annular shaped drying zone 5. At the lower end of the drying zone 5, there is introduced a continuous hot combustion gas stream by means of a distributing header l I which in turn is supplied with hot combustion gases through conduit I2 having control valve I3.

A suiicient quantity of hot combustion gases is supplied to the drying zone to maintain a uidized and hindered settling condition within that zone, and to insure the drying or complete coking and devolatilization of asphaltic materials which may be occluded in or absorbed onto the coke particles as they leave the upper portion of the coking zone. In an accumulating zone I4, within the lower portion of the chamber I, the dried coke particles are permitted to collect into a relatively dense phase bed. To preclude compacting within this coke accumulating zone I4, a continuous stream of hot combustion gases is distributed by means of a header l5 and the line I6, having control valve II. The gaseous medium supplied through header l5 provides not only fiuidization of the coke particles within the accumulating zone, but, in addition obtains in part a gravitational separation of the heavier from lighter, or coarser from finer, particles so that primarily relatively ne uiy coke particles are gathered at the lower end of the coking zone 4, for introduction and recycle into the coking zone, while heavier coke particles gravitate to the discharge conduit 32.

A feature of the present invention is the continuous recirculation of coke particles from the accumulating zone I4 into the coking zone ll by their aspiration through a restricted opening I8 at the lower end of the zone Li, and by means of a hot combustion gas stream being supplied through line I9 and control valve 20. The aspiration of coke particles upwardly through the opening I8 is fostered by the differential maintained between the densities of the luidized mass within the coking zone d and the uidized bed in at least the lower portion of the annular drying zone 5, the density of the descending iluidized bed in the latter being maintained generally greater than the density of the ascending fluidized mass within the coking zone d by controlling the relative gas flow rates through these contacting zones in such manner that the average velocity of upward now of the iluidized coke particles in the coking zone is substantially greater than the average velocity of net downward iiow of the fluidzed coke particles in the drying zone 5. The gas now rates through the contacting zones are limited, however, to the extent that sufficient gas must be passed upwardly through the drying zone 5 to preclude compacting of the coke particles therein, that is to say, to preclude formation of a bed in which the coke particles would travel substantially at a uniform rate and substantially without motion relative to each other, while not more gas must be passed through the coking zone than permits separation of at least the bulk, and preferably of substantially all of the coke particles from the gases and vapors in the separating zone 2 of substantially larger cross-section than that of the coking zone Il.

Hot combustion gas issuing from the line le, which preferably terminates in a distributing nozzle directing the gas upwardly in ne jets, aids in propelling a stream or' the hot coke particles, and more particularly relatively ne particles continuously from the accumulating zone la upwardly into the uidized bed maintained within the coking zone d. This gas stream also supplements the heat supply to the coking zone, so that the heat supplied to the latter comprises the total effect from hot coke particles from the drying and accumulating zone, hot combustion gas from the line IS, and the resulting hot fluid stream issuing from the dispersing device or nozzle 8 which sprays the oil charge with a hot combustion gas atomizing medium. The relative quantities of gas introduced through each of the noz- Zles is controlled with respect to each other, as well as to the quantity of hydrocarbon charge and the size of the coking zone, to effect a desirable coking temperature and rate of flow for the continuously rising bed of particles within the cokng and conversion zone.

At the upper end of the chamber l, the hot vapor-ous and gaseous product streams, which ascend from the coking zone li and the drying zone and substantially separate from the solid particles in the separating zone 2, are withdrawn through transfer line 23, having control valve 24. Since these streams usually carry a small amount of entrained coke nes, they may be passed through particle separators 2l, such that a substantially clean gas-vapor product stream may be withdrawn through the

respective lines

22 and 22 and discharged by way of transfer line 23, while recovered coke particles are returned to the drying zone through suitable dip-legs from each of the separators 2i. The mechanical particle separators El, however, may be omitted in some cases, particularly when a separation zone 2 of suicient height and width to permit substantially complete separation of solid particles from the vaporous product mixture can be provided, or when the hot vaporous product stream to be fractionated is quenched with hydrocarbon oil charge.

In accordance with a particular feature of this invention, a portion of the gas-vapor mixture being withdrawn through line 23, is passed by Way of line control valve 2B and blower 2l to a flue gas or combustion gas generator 28. An air or oxygen-containing stream is supplied to the generator 2t by means of line 29 and control valve 3D, such that at least a portion of the cornbustible components may be burned to supply hot combustion gases to the unit as described above. The hot gasiforin mixture passing by way of line .25 to the combustion gas generator is preferably transferred with as little heat loss as possible in order to obtain a thermally eflicient operation of the unit, and in order to minimize the requirements of the oxygen or air stream being introduced to the combustion gas zone. The quantity of gas recirculated is of course controlled and regulated together with the amount of air charged through line 29 to the combustion gas generator so as to insure the supply or" fluidizing and atomizing gas at the desired temperature level and in adequate amounts within the conversion unit. Moreover, the air or other oxygen-containing gas and the vaporous product stream from line 25 are introduced to the gas generator 2i in such proportion that the resultant hot combustion gas is substantially devoid of free oxygen or contains a substantial proportion of unburnt combustible components.

A particular advantage of 'the present coking operation resides in the heat conservation which is attained by the continuous circulation of coke particles through the coking zone 4 and the drying zone 5 within the confines of the chamber l and by the continuous circulation of gas through the contacting zones t and 5, the gas generator 28, and the connecting conduits therebetween, including

lines

23 and 25 with practically no drop in temperature of the circulating gas at any part of the cycle outside chamber l. During normal continuous operation, the portion of the vaporous mixture diverted from line 23 through line 25 to the gas generator constitutes only a minor portion of the gas-vapor stream issuing from the separating zone, by far the greater portion of this gas-vapor stream being available for preheating the hydrocarbon charge stream and for recovery of valuble low boiling products. It is to be understood, of course, that in starting the operation, an adequate supply of coke particles from an outside source or a previous operation is provided in chamber I and a preferably gaseous fuel from storage or other external source is supplied to the gas generator 23 for controlled combustion therein with supply of resultant hot gases to the chamber l in an amount sufcient to rst establish the circulation of hot coke particles therein, whereupon the introduction of hydrocarbon oil charge through line is started and gradually increased t0 optimum rate and the supply of fuel from outside the system is reduced and replaced increasingly by recirculated hot vaporous product mixture until the system is in balanced operation.

Although excess coke particles which are accumulated within the lower portion of the unit and zone i!! may be withdrawn as dry particulated coke, it is also a feature of the present invention to provide means for passing the coke particles to a quenching and coke slurrying zone as provided by chamber 3l. The coke particles are continuously withdrawn in a stream through a vertical conduit 32 and control valve 33, to be subsequently deposited Within the quenching zone 3l where they may be cooled by a suitable quenching medium. The coke particles within chamber 3i may be contacted and quenched with Water or oil or other suitable fluid medium; however, in the embodiment illustrated, water is supplied by means of line .f2-' and control valve 35 to pass upwardly countercurrently to the coke particles to eect a cooling thereof and the generation of steam. Resulting steam is withdrawn through a particle separator' 36 and passed by Way of line 3l and valve Re to a suitable steam drum or to other portions of the unit as may be required, the flow of the steam being controlled by valve 38. The steam generating and quenching zone may be used to advantage to provide a stripping medium for contacting the coke particles within the transfer conduit and the lower accumulating zone it. As indicated, the steam may be introduced to the coke accumulating zone Hl by means of line 39 and control valve G, while Steam may also be introduced into the transfer conduit 32 by means of line 4i and valve 2. Resulting cooled coke may be withdrawn from the lower portion of the quenching and coking tower by means of outlet line [13 and control valve lill. The coke is thus easily transferred to a receiving zone in a slurry stream and in a cooled condition.

The coking operation may be carried out at any desired subatmospheric, substantially atmospheric or superatmospheric pressure. The operating pressure is maintained substantially uniform in the chamber l and the coke quenching tower 3l with only such minor pressure differences between the several contacting zones and the quenching Zone as result from hydrostatic heads of the uidized bede in the chamber l and the head of the coke down-flow stream in line 32. While subatmospheric pressure generally favors the rapid volatilization of the noncoking portion of the heavy oil charge and the drying or devolatilization of the coke particles, the apparatus must necessarily be of larger dimensions for a given charging rate at a subatmospheric pressure than when operating at a higher pressure, and for this reason and in order to facilitate the discharge of cooled coke slurry from tower 3l intov receptacles at atmospheric pressure and avoid the necessity of compressing the vaporous product mixture to be fractionated it is preferred to effect the coking operation at a moderate superatmospheric pressure in the order of from l to 50 pounds per square inch, gauge. lThe quenching of the vaporous product mixture tc be fractionated is effected promptly upon its passage through Valve 24 in line 23 and preferably at only a slightly lower pressure than that maintained in the upper or separating portion of chamber I, the pressure difference across the valve 24 being maintained merely sufficient to secure a steady flow of the materials through chamber E and line 25.

The colre which is produced in this process may be utilized as fuel; however, the substantially pure form of coke which is obtained by this method from hydrocarbon oils is also suitable vas a starting material for electrode carbon manufacture, metallurgical coke and the like.

The fractionating and recovery system to which the vapor-gas product stream is passed from the coking zone is not shown in the present drawing; however, any suitable form of fractionating system may be utilized to recover the desired valuable hydrocarbon fractions, including olenic gases, gasoline fractions of high antiknock value. or aromatics and the like. In a specific and desirable embodiment of the invention, the heavy hydrocarbon stream which is to be coked in the unit, is used as the quenching medium to contact the product stream discharged from line y23, whereby to cool the latter as well as preheat the charge stream prior to its introduction into the coking Zone. By using this stream as the quenching medium, there may be incorporated entrained high boiling components of the gasiform product mixture into the oil charge.

It is of course understood that the exact ar rangement of the several zones in the shapes and proportions indicated in the drawing is not to be limiting, for obvious minor variations in the dimensioning and positioning of the zones, and in the location of the points of introduction and withdrawal of the various streams may be made in accordance with conventional engineering and design practice without departing from the spirit and scope of the invention.

I claim as my invention:

1. A method for converting a hydrocarbon charge stream into lower boiling products and coke particles, comprising dispersing said hydrocarbon charge stream upwardly into a confined coking zone concurrently with a heat-carrying gaseous medium and heated rluidized coke parti cles, eiecting a high temperature contact between said particles and said dispersed stream and during said contact transforming said hydrocarbon charge into vaporous distillation and conversion products and additional coke, discharging resulting coke particles from the upper por tion of the coking zone and passing them downwardly in a coni-ined drying zone contiguous with said coking zone and maintained under non-oxidizing conditions, passing a hot gaseous non-oxidizing drying medium into and upwardly through said drying Zone and heating and maintaining said particles in a iuidized phase by the ascending drying medium, devolatilizing the coke particles in said drying zone by the heat of said drying medium while precluding combustion of any appreciable quantity of the particles, introducing a portion of the resulting heated and dried particles from the lower portion of said drying zone upwardly into and concurrently with said gaseous heat-Carrying medium through said coking zone and into contact therein with said hydrocarbon charge stream, discharging vaporous products from the upper portions of the coking and drying zones, and withdrawing excess coke particles from the lower portion of the drying zone.

2. A method for converting a hydrocarbon charge stream into lower boiling products and coke particles, which comprises dispersing said hydrocarbon charge stream upwardly into a conned coking zone concurrently with a gaseous heatcarrying medium, effecting a high temperature contact of the dispersed stream and gaseous medium with an ascending fluidized bed of heated coke particles within said coking zone and during said contact transforming said hydrocarbon charge into gasiform distillation and conversion products and additional coke, discharging coke particles from the upper portion of the coking zone and passing them downwardly in a conrlned drying zone contiguous with said coking zone and maintained under non-oxidizingconditions, passing a hot gaseous non-oxidizing drying medium into and upwardly through said drying zone and therein heating and maintaining said particles in a descending rluidized bed, devolatilizing the coke particles in said drying zone by the heat of said drying medium while precluding combustion of any appreciable quantity of the particles, introducing a portion of the resulting heated and dried particles from the lower portion of said drying zone with the aid of at least a portion of said gaseous .heat-carrying medium upwardly into said coking zone and said ascending fluidized bed and kinto contact therein with the dispersed hydrocarbon charge stream, discharging gasiforin products from the upper portions of both the coking and drying zones, and withdrawing excess coke particles from the lower portion yof said drying Zone.

3. A method for converting a hydrocarbon charge stream into lower boiling products and coke particles, which comprises dispersing said hydrocarbon charge stream with the aid of a stream of a gaseous heat-carrying medium upwardly into an ascending fluidized bed oi hot coke particles in a coking zone and therein transforming said charge stream into gasiform distillation and conversion products and additional coke, discharging the resulting coke particles from the upper portion of the coking Zone and passing them downwardly in a coniined drying zone contiguous with said coking Zone and maintained under non-oxidizing conditions, passing a hot gaseous non-oxidizing drying medium into and upwardly through said drying zone and therein heating and maintaining said particles in a descending fluidized bed, devolatilizing the coke particles in said drying zone by the heat of said drying medium while precluding combustion of any appreciable quantity of the particles, introducing a portion of the resulting heated and dried particles from the lower portion of said drying zone with the aid of another stream of said gaseous heat-carrying medium upwardly into said coking zone and said ascending iluidized bed and into contact therein with the dispersed hydrocarbon charge stream, discharging gasiiorm products from the upper portions of both the coking and drying zones, and withdrawing excess coke particles from the lower portion of said drying zone.

4. A method for converting a heavy hydrocarbon oil stream into lower boiling products and coke particles, which comprises dispersing said hydrocarbon oil stream upwardly into a confined coking zone concurrently with hot combustion gases and heated fiuidized coke particles, eiiecting a high temperature contact between said particles and the dispersed hydrocarbon stream and during said contact converting the latter stream into gasiform distillation and conversion products and additional coke, discharging the resulting coke particles from the upper portion of the coking zone and heating the same while passing them downwardly in a coniined drying zone maintained adjacent to and in heat exchange relationship with the coking zone and maintained under non-oxidizing conditions, introducing additional hot combustion gases to the lower portion of the drying zone to countercurrently contact and fluidize the descending coke particles therein, devolatilizing the colte particles in said drying zone by the heat of said additional hot gases while precluding combustion of any appreciable quantity of the particles, injecting a portion of the resulting heated and dried particles to the lower portion of said coking zone with a stream of hot combustion gases whereby to provide coke particles for effecting the iuidized contact with the dispersed hydrocarbon stream, discharging gasiiorm products from the upper portions of both the coking and drying zones, and withdrawing excess coke particles from the lower portion of the latter zone as a stream of particulated coke.

I5. The method of claim 4 further characterized in that said combustion gases introduced into the lower portions of the coking zone and the drying zone are supplied from a combustion gas generating zone, maintained separate from said coking and drying zones, and a portion or said gasiform product stream and an oxygen-containing gas stream are introduced into said generating zone whereby to effect the production of said hot combustion gases.

6. The method of claim 5 further characterized in that said heated fluidized coke particles are maintained in an upwardly moving iiuidize"1 bed within said coking zone and said hydrocarbon oil stream is mixed with a separate stream of hot combustion gases within the lower portion of said coking and conversion zone whereby to eiect the dispersing of said hydrocarbon stream into said upwardly moving bed of fluidized coke particles.

'7. A method for converting a heavy hydrocarbon oil stream into lower boiling materials and colte particles, which comprises passing said hydrocarbon stream upwardly in an atomized spray within a conned colring zone concurrently with heated fiuidized coke particles, mixing hot combustion gas with said oil stream to form said atomized spray thereof and passing hot combustion gas to the lower end of said coking zone to iiuidize said heated coke particles moving ccncurrently upwardly through said zone for contact with said spray, effecting the conversion of said hydrocarbon stream to gasiform products and additional coke, passing the resulting coke particles from the upper portion of said coking zone into a descending annular column of particles maintained within a conned drying zone circumscribing said coniined coking zone and maintained under non-oxidizing conditions, passing additional hot combustion gases upwardly through said drying zone countercurrently to said descending annular column and therein uidizing, heating and drying the particles, devolatilizing the coke particles in said drying zone by the heat of said additional hot gases while precluding combustion of any appreciable quantity of the particles, discharging resulting gasiform products from the upper portions of both the coking and drying zones and a stream of the resulting heated and dried coke particles from the lower portion of said annular column into the lower portion of the coking zone, subsequently passing a portion of said gasiforrn products to a combustion gas generating zone, introducing an oxygen-containing gas stream to said combustion gas generating zone and producing therein high temperature combustion gases, said gases being introduced to the lower portions of said coking zone and said drying zone as hereinbefore dened, withdrawing excess coke particles from the lower portion of said drying zone and passing them in a gravity flow to a quenching zone maintained therebelow, quenching said particles with a iiuid stream passing countercurrently upwardly through said descending particles within said quenching zone, discharging a heated iiuid stream from the upper portion of the quenching zone and discharging a slurried coke stream from the lower portion thereof.

3. The method of claim '7 further characterized in that said fluid quenching stream comprises water, and steam is discharged from the upper portion of said quenching zone, a stream of said steam being passed to the lower portion of said drying zone to strip said coke particles prior to their discharge therefrom into said quenching zone.

9. A unitary apparatus for effecting the conversion of a hydrocarbon charge stream into lower boiling products and particulated coke in the presence of finely divided solid material which comprises in combination, a vertically disposed contacting chamber, a quenching chamber below said contacting chamber, a vertical annular partitioning member disposed within and spaced a s bstantial distance from the top and bottom of said contacting chamber and forming an openended internal contacting section and a contiguous annular contacting section, said partitioning member being formed with a restricted opening at the lower end thereof, an upwardly directed gas inlet means terminating within said restricted opening and suitable for propelling solid particles upwardly therethrough, a fluid feed dispersing means within the lower portion of said internal contacting section, a hydrocarbon feed conduit connecting with said dispersing means, additional gas inlet and distribution means within the lower portion of said annular contacting section suitable for effecting uidization of solid particles therein, a combustion gas generating means adjacent said contacting chamber, said combustion gas generating means having a fuel inlet and connecting with said upwardly directed gas inlet means and with said additional gas inlet and distribution means, a connecting conduit extending from the bottom portion of said contacting chamber into the upper portion of said quenching chamber for the discharge of solid particles from the former to the latter, particle outlet means and fluid inlet means at the lower portion of said quenching chamber and fluid outlet means at the upper portion thereof, said fluid outlet means communicating with a branch conduit for the supply of fluid from said quenching chamber to the bottom portion of said contacting chamber, a vapor outlet at the upper portion of said contacting chamber, and a conduit with ow control means connecting said vapor outlet with said fuel inlet to permit the transfer of a portion of the gasiform product stream from said contact chamber to said combustion gas generating means.

10. The apparatus of claim 9 further characterized in that a dspersing gas inlet is provided at said fluid feed dispersing means and a conduit with flow control means connects said combustion gas generating means with said dispersing gas inlet.

11. The process of claim 1 further characterized in that a portion of said discharged vaporous products is burned to produce hot combustion gases substantially devoid of free oxygen and in that separate portions of said combustion gases are introduced to the coking zone and to the drying zone as .said heat-carrying medium and said drying medium, respectively.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Hubmann Sept. 1, 1925 Puening Apr. 25, 1933 Trent Oct. 24, 1933 Lambiotte July 14, 1942 Kuhl Jan. 25, 1944 Myers Feb. 8, 1944 Voorhees June 12, 1945 Johansson May 13, 1947 Scharmann et al. Mar. 2, 1948 Keith July 20, 1948 Lnatz Aug. 31, 1948 Nelson Jan. 15, 1952 Schutte et al June 10, 1952

Claims

2. A METHOD FOR CONVERTING A HYDROCARBON CHARGE STREAM INTO LOWER BOILING PRODUCTS AND COKE PARTICLES, WHICH COMPRISES DISPERSING SAID HYDROCARBON CHARGE STREAM UPWARDLY INTO A CONFINED COKING ZONE CONCURRENTLY WITH A GASEOUS HEAT-CARRYING MEDIUM, EFFECTING A HIGH TEMPERATURE CONTACT OF THE DISPERSED STREAM AND GASEOUS MEDIUM WITH AN ASCENDING FLUIDIZED BED OF HEATED COKE PARTICLES WITHIN SAID COKING ZONE AND DURING SAID CONTACT TRANSFORMING SAID HYDROCARBON CHARGE INTO GASIFORM DISTILLATION AND CONVERSION PRODUCTS AND ADDITIONAL COKE, DISCHARGING COKE PARTICLES FROM THE UPPER PORTION OF THE COKING ZONE AND PASSING THEM DOWNWARDLY IN A CONFINED DRYING ZONE CONTIGUOUS WITH SAID COKING ZONE AND MAINTAINED UNDER NON-OXIDIZING CONDITIONS, PASSING A HOT GASEOUS NON-OXIDIZING DRYING MEDIUM INTO AND UPWARDLY THROUGH SAID DRYING ZONE AND THEREIN HEATING AND MAINTAINING SAID PARTICLES IN A DESCENDING FLUIDIZED BED,