U.S. patent number 3,642,202 [Application Number 05/036,733] was granted by the patent office on 1972-02-15 for feed system for coking unit.
This patent grant is currently assigned to Esso Research and Engineering Company. Invention is credited to Jake B. Angelo.
United States Patent |
3,642,202 |
Angelo |
February 15, 1972 |
FEED SYSTEM FOR COKING UNIT
Abstract
A mist of atomized hydrocarbonaceous feed material is sprayed
through a nozzle into a fluid coking zone without disruption due to
coke buildup in and on the nozzle by discharging the
hydrocarbonaceous feed through the orifice of a
temperature-regulated axial passageway into a confluence of several
high-velocity gas jets issued from separate ports spaced about the
periphery of the feed passageway orifice. Preferably, the several
gas jets are tangentially impinged upon the feed stream so as to
shearingly whirl the feed stream about the axis of the feed
passageway to produce the mist. Before issuance to produce the
mist, the gaseous material forming the jets are preferably deployed
in an annulus stream about the axial passageway to cool the feed
passageway to prevent coking of the feed in the passageway. An
apertured shield coaxially surrounds the ports and orifice to
peripherally protect the ports and the orifice from hot fluidized
solids in the coking zone. Gaseous materials separate from the
gaseous materials forming the jets are streamed along the exterior
of the apertured shield to wipe the shield free of solids from the
coking zone. The stream of wiping gas aids the atomization of the
hydrocarbonaceous feed.
Inventors: |
Angelo; Jake B. (Rockaway,
NJ) |
Assignee: |
Esso Research and Engineering
Company (N/A)
|
Family
ID: |
21890317 |
Appl.
No.: |
05/036,733 |
Filed: |
May 13, 1970 |
Current U.S.
Class: |
239/8; 239/422;
239/400; 239/403; 239/424 |
Current CPC
Class: |
B05B
7/10 (20130101); B01J 4/002 (20130101); B05B
7/066 (20130101); C10B 55/00 (20130101) |
Current International
Class: |
C10B
55/00 (20060101); B05B 7/02 (20060101); B05B
7/10 (20060101); B05B 7/06 (20060101); A01n
017/02 () |
Field of
Search: |
;239/400,403,405,424,424.5,8,132,132.1,132.3,422 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: King; Lloyd L.
Claims
I claim:
1. Apparatus for spray feeding a mist of hydrocarbonaceous material
into a fluid coking zone for coking on hot, finely divided
fluidized solids, which comprises:
a nozzle having a confined passageway of constant diameter, an
inlet at one end of such passageway for admission of a stream of
hydrocarbonaceous material, a discharge orifice at the other end of
such passageway for discharge of said hydrocarbonaceous material
into said coking zone,
means immediately surrounding said passageway for maintaining the
temperature of said passageway sufficiently lower than the
temperature in said coking zone to prevent coking of feed passing
through said passageway and
a plurality of gas jetting ports spaced apart on the periphery of
said discharge orifice, equidistant from the center of said
passageway, and in confined and fluid communication with means for
supplying gaseous material to such ports, for jetting, effective to
prevent plugging of said ports, a plurality of jets of gaseous
material into said coking zone onto said hydrocarbonaceous material
as such hydrocarbonaceous material discharges from said discharge
orifice, so as to atomize such hydrocarbonaceous material in the
coking zone.
2. The nozzle of claim 1 in which said spaced-apart gas jetting
ports are disposed tangentially to said discharge orifice for
tangential jetting of said gaseous material onto said
hydrocarbonaceous material discharging into said coking zone to
shearingly whirl and atomize said hydrocarbonaceous material.
3. Self-cleaning nonplugging apparatus for spray feeding a mist of
hydrocarbonaceous material into a fluid coking zone for coking on
hot, finely divided fluidized solids, which comprises:
a nozzle having a confined, axial passageway, an inlet at one end
of such passageway for admission of said feed stream of
hydrocarbonaceous material, and a discharge orifice at the other
end of such passageway for discharge of said hydrocarbonaceous
material into said coking zone,
means defining an annular passageway immediately surrounding said
passageway posteriorly of said orifice and having an inlet for
admitting a gaseous temperature regulating material for maintaining
the stream of hydrocarbonaceous material passing through said
passageway at a temperature sufficiently lower than the temperature
in said coking zone to prevent coking of the feed in said
passageway and clogging thereof,
a plurality of gas jetting means terminating in a plurality of
ports spaced apart on the periphery of said discharge orifice and
equidistant from the axis of said passageway, said gas jetting
means being in confined and fluid communication with said annular
passageway for jetting of said gaseous temperature-regulating
material through said ports into said coking zone onto said
hydrocarbonaceous material as such hydrocarbonaceous material
discharges from said orifice into said coking zone, to atomize such
hydrocarbonaceous material without plugging of said ports,
an apertured shield immediately surrounding said spaced-apart ports
and peripherally protecting said ports and said orifice from solids
in said coking zone as said gaseous temperature regulating means
and said hydrocarbonaceous material pass into said coking zone
through the aperture thereof, and
a plurality of gas conduits having inlets for admitting gaseous
material thereinto and terminating in a plurality of outlets spaced
apart about the periphery of said shield for streaming said gaseous
material along the exterior of said shield to wipe said shield free
of solids from said coking zone.
4. The nozzle of claim 3 in which said ports of said gas jetting
means are axially oriented to the axis of said axial passageway at
an angle within the range from about 0.degree. to about 90.degree.
.
5. The nozzle of claim 3 in which said ports of said gas jetting
means are inclined to said discharge orifice at an angle within the
range from about 30.degree. to about 75.degree. .
6. A self-cleaning feed nozzle for plug-free spray feeding a mist
of hydrocarbonaceous material into a fluid coking zone for coking
on hot, finely divided solids, which comprises:
a tube with an axial bore having an inlet at one extremity of the
tube for admitting said feed stream of hydrocarbonaceous material
and an outlet at the other extremity of the tube for discharge of
the hydrocarbonaceous material, said tube tapering at the outlet
end thereof to an angle within the range from about 30.degree. to
about 75.degree. to define the frustum of a cone having a base
diameter equal to the diameter of the tube and a top diameter equal
to the diameter of the bore of the tube, said top comprising a rim,
the external surface of said frustum having a plurality of grooves
extending from the base of the frustum to spaced-apart positions
about said rim,
a tubular frustoconical cap to shield the tapered extremity of said
tube from solids in said coking zone, said cap having an internal
surface with the same taper as the taper of said frustum of said
tube and an external surface with a greater angle of taper than the
taper of such frustum, said cap coaxially matingly fitting over
said frustum of said tube so that said internal surface of said cap
over said grooves in said frustum defines a plurality of confined
channels having inlets at the base of the frustum and outlet ports
spaced apart about the rim of the frustum,
a sleeve surrounding said tube and attached at one end to the base
of said frustoconical cap between the inner and outer surfaces
thereof and defining between said tube and said sleeve an annular
passageway terminating at the base of said frustum of said tube in
fluid communication, through said confined channels, with said
spaced outlet ports, said sleeve having at its other end inlet
means for admitting a gaseous temperature-regulating material into
said annular passageway for maintaining the stream of
hydrocarbonaceous material fed through said axial bore at a
temperature lower than the temperature in said coking zone whereby
coking of said hydrocarbonaceous material in said bore and clogging
of said bore is prevented, said gaseous temperature regulating
material thence issuing in separate jets from said spaced outlet
ports about said rim onto said hydrocarbonaceous material as it
discharges into said coking zone to effect misting of said
hydrocarbonaceous material in said coking zone, and
a plurality of confined shroud gas conduits fluidly separated from
said annular passageway and having inlets for admitting gaseous
materials and axial outlets spaced apart around the periphery of
said external surface of said cap and axially aligned at the same
angle of taper as the external surface of said cap for streaming
said gaseous material along said external surface to wipe such
surface free of solids from said coking zone.
7. The nozzle of claim 6 in which said spaced outlet ports of said
confined channels are tangentially disposed to said rim for
tangential jetting of said gaseous temperature regulating material
onto said hydrocarbonaceous material as it discharges from the
outlet in the tapered extremity of the tube so as to shearingly
whirl the stream of hydrocarbonaceous material about the axis of
the tube to produce the mist in said coking zone.
8. The nozzle of claim 7 in which said spaced outlet ports are
axially oriented to the axis of said tube at an angle within the
range from about 0.degree. to about 90.degree. .
9. The nozzle of claim 8 in which the angle of taper of said tube
is within the range from about 45.degree. to about 60.degree. .
10. The nozzle of claim 9 in which said angle of taper of said tube
is 30.degree. and wherein said ports are axially oriented at a
45.degree. angle to the axis of said tube.
11. A process for spray feeding hydrocarbonaceous material into a
coking zone containing a fluidized bed of hot, finely divided
solids from a spray nozzle without clogging of the nozzle, which
comprises:
passing the feed stream along an axis through a
temperature-regulating zone adjacent said coking zone, and thence
along said axis directly through an entrance into said coking
zone,
regulating the temperature of said feed in said temperature
regulating zone with a gaseous temperature-regulating material
maintained at a temperature lower than the temperature in said
coking zone so as to prevent coking of the feed in its passage to
said coking zone, and
flowing said gaseous temperature regulating material from said
temperature-regulating zone and jetting said gaseous
temperature-regulating material in a plurality of separate jets
circumferentially convergent upon said feed stream as said feed
stream enters said coking zone to atomize said feed stream into a
mist in said coking zone.
12. The process of claim 11 in which said streams of gaseous
temperature regulating material are tangentially jetted onto said
stream of hydrocarbonaceous material so as to shearingly whirl the
stream of hydrocarbonaceous material about the axis of said feed
stream to produce said mist in said cooling zone.
13. The process of claim 12 in which said separate gaseous streams
are jetted onto said feed stream at a velocity ratio, relative to
the velocity of said feed stream, within the range from about 2 to
about 4 and a gas-to-oil specific volume ratio relative to said
feed stream within the range from about 1 to about 5.
14. Apparatus for spray feeding a mist of hydrocarbonaceous
material into a fluid coking zone for coking on hot, finely divided
fluidized solids, which comprises:
a nozzle having a confined passageway of constant diameter, an
inlet at one end of such passageway for admission of a stream of
hydrocarbonaceous material, a discharge orifice at the other end of
such passageway for discharge of said hydrocarbonaceous material
into said coking zone,
means immediately surrounding said passageway for maintaining the
temperature of said passageway sufficiently lower than the
temperature in said coking zone to prevent coking of feed passing
through said passageway, and
a plurality of gas jetting ports spaced apart on the periphery of
said discharge orifice, equidistant from the center of said
passageway, and in confined and fluid communication with means for
supplying gaseous material to such ports, for jetting, effective to
prevent plugging of said ports, a plurality of jets of gaseous
material into said coking zone onto said hydrocarbonaceous material
as such hydrocarbonaceous material discharges from said discharge
orifice, so as to atomize such hydrocarbonaceous material in the
coking zone,
an apertured shielding means immediately surrounding said
spaced-apart gas jetting for peripherally shielding said gas
jetting means and said orifice from solids in said coking zone as
said gaseous material and said hydrocarbonaceous material pass into
said coking zone through the aperture thereof, and
a plurality of spaced-apart shroud gas conduit means surrounding
said apertured shielding means for streaming gaseous materials
along the exterior of said shielding means to wipe said shielding
means free of solids from said coking zone.
Description
BACKGROUND OF THE INVENTION
This invention involves a system for spraying hydrocarbonaceous
feed materials such as a coal liquefaction extract or a petroleum
residuum from a spray nozzle into a fluid coking zone without
disruption of the spray due to clogging of the nozzle with
accumulated coke.
When liquid phase or mixed solid and liquid phase hydrocarbonaceous
feed materials are properly introduced into a coking zone
containing a fluidized bed of hot, finely divided solids, some
portions of the feed material are vaporized instantly and are
recovered from the coking zone as product. Other portions, which
wet the hot, finely divided fluidized particles, are thermally
cracked by the heat of the particles to form coke and cracked
products which are evolved as vapor from the coking zone. Fluid
coking is effective so long as bogging of the bed is avoided.
Bogging, for example, occurs if the hydrocarbonaceous feed is
introduced into the fluid coking zone in a manner which overwets
the finely divided solids, causing clumping or agglomeration of the
particles. Overwetting generally occurs when a fog or mist of
hydrocarbonaceous material sprayed into a fluid coking zone is so
distorted that the spray into the zone is unevenly distributed, or
so disrupted that, instead of a mist, a liquid jet of the feed
material is injected into the bed. The prime source of spray
disruption and distortion is plugging and clogging of the spraying
device due to the formation and buildup of coke in and on it.
Plugging and clogging of known spray nozzles can occur in several
ways. When an atomizing gas and a mixed solid and liquid phase
hydrocarbonaceous feed material are contacted in a nozzle feed tube
conducting the material to a coking zone, the gas can strip away
the liquid portion of the feed from the solid portion, and the
solids can plug the feed tube. U.S. Pat. Nos. 2,786,801, and No.
3,071,540, typify spray or mist generating apparatus plagued with
another type of plugging problem. These spray devices utilize an
axial tube to feed a liquid hydrocarbonaceous material through a
discharge orifice into a solid annular stream of gas jetted through
an annular outlet from an annular passageway formed around the
axial feed tube, as by a second tube coaxially surrounding the feed
tube. In these devices, when a particle of coke material deposits
in a portion of the annular outlet through which the gaseous stream
is jetted, the gaseous material bypasses the deposit and escapes
the outlet through portions of the annular outlet which are
unobstructed and which offer less resistance. The coke deposit in
the annular outlet serves as a seed for coking of hydrocarbonaceous
material so that coke continues to be formed in the outlet, not
being dislodged because the gas continues preferentially to escape
through remaining areas of lesser resistance in the outlet, until
eventually the outlet is so choked with coke that the spray pattern
of the nozzle is seriously distorted or insufficient gas escapes
from the outlet to disperse the feed stream into a spray, with
consequent bogging of the fluidized bed.
To prevent these causes of bogging in coking zone fluidized beds
and to reduce coking reactor downtime to clean plugged-up feed
spray nozzles, a spray system is needed in which fluid passageways
and outlets do not become choked, clogged and plugged due to coke
buildup and accumulation when a hydrocarbonaceous feed is sprayed
into the fluid coking zone. This invention fulfills that need by
providing a self-cleansing spraying system. It also provides a
system for effecting an improved spray into a fluid coking
zone.
SUMMARY OF THE INVENTION
A self-cleansing spraying system for spraying a mist of
hydrocarbonaceous material into a fluid coking zone is provided by
discharging a feed stream of the hydrocarbonaceous material from an
orifice of a confined axial passageway into the fluid coking zone
and jetting atomizing gaseous streams from a plurality of separate
ports spaced about the periphery of such orifice onto the feed
stream as the feed stream emerges from the orifice. By jetting the
gaseous material through the plurality of spaced, separate ports,
the gas is forced to escape through the port it enters, causing
sufficient pressure to build behind any accumulation of coke in
that outlet to dislodge that coke. Before being jetted through the
ports to disperse the hydrocarbonaceous stream into a spray, the
gaseous material of the gas jets is preferably employed to cool the
feed passageway to prevent premature coking of the feed and
plugging of the passageway. In this system, the spaced ports for
the gas jets and the hydrocarbonaceous material discharge orifice
are peripherally protected from solids in the coking zone which
promote coke formation by an apertured shield which coaxially
surrounds the ports and the orifice to admit the gas and
hydrocarbonaceous material into the coking zone through the
aperture. Gaseous streams fluidly separated from the gas jets and
emitted from a plurality of conduits spaced apart about the
periphery of the apertured shield wipe the shield free of solids
from the coking zone to prevent coke buildup on the external
surface of the nozzle in the coking zone.
In one aspect of this invention, an improved spray of the
hydrocarbonaceous feed is obtained by jetting the gaseous material
tangentially upon the hydrocarbonaceous feed discharging from the
feed passageway orifice so as to shearingly whirl the feed stream
about the axis of the feed passageway. The stream of gas wiping the
shield also aids in atomization of the hydrocarbonaceous feed.
The methods of spraying the mist of hydrocarbonaceous material into
the fluid coking zone in a self-cleansing manner and a preferred
form in which the system of the invention is embodied is described
in connection with the drawings which illustrate the preferred
embodiment.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic longitudinal section of an atomization nozzle
constructed in accordance with this invention;
FIG. 2 is a top plan view of the atomization nozzle of FIG. 1,
particularly illustrating the nozzle cap;
FIG. 3 is a schematic elevational view of the tip of the feed tube
of the atomization nozzle of FIG. 1, with the cap of the nozzle in
cross section;
FIG. 4 is a top plan view of the nozzle tip of FIG. 3;
FIG. 5 is another configuration for the channels and the nozzle tip
in the embodiment of FIG. 1;
FIG. 6 is a top plan view of the nozzle of FIG. 5;
FIG. 7 is still another form of the nozzle tip embodied in FIG. 1;
and
FIG. 8 is a top plan view of the nozzle tip of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, reference numeral 10 indicates a confined
axial passageway in the bore of a tube 11 for introduction of a
hydrocarbonaceous material, such as a mixed liquid and solid phase
coal liquefaction product, into a coking zone A. The extremity of
the tube 11 opposite the inlet 12 is tapered externally at an angle
suitably within the range from about 30.degree. to about
75.degree., here illustrated as a 30.degree. angle taper. The axial
passageway 10 defined by the bore of tube 11 is maintained at
constant diameter throughout tube 11. The perimeter of the axial
passageway 10 intersects the tapering external diameter of the tube
11 to define a rim 13. Between the rim 13 and the point of initial
taper of tube 11, a nozzle tip 14 is defined in the form of a
frustum of a cone, the frustum thus having a base diameter equal to
the diameter of the tube and a top diameter equal to the diameter
of the bore of the tube. The rim 13 of the tip 14 delineates an
outlet orifice 15 for discharge of the hydrocarbonaceous feed
introduced into tube 11 through inlet 12.
Referring to FIGS. 3-8, the face 16 of frustoconical tip 14 is
channeled with a plurality of grooves 17 extending from the base of
the cone, indicated by reference numeral 18, to the rim 13 of the
frustoconical tip. The grooves 17 are separated to define
spaced-apart notches 19 in rim 13 of the tube tip.
Returning to FIG. 1, reference numeral 20 indicates a tubular
frustoconical cap provided with an axial aperture 21 in the top of
the cap of substantially the same diameter, but in any case of no
smaller diameter, than the diameter of the bore 10 of tube 11, cap
21 being tapered along internal surface or wall 22 at the same
angle of taper as the frustoconical tip 14 of tube 11, such that
cap 20 coaxially and matingly fits over frustoconical tip 14 of
tube 11 and defines a plurality of confined channels under the
portions of the inner surface wall 22 overlaying the grooves 17 in
face 16 of the frustoconical tip. The confined channels thus extend
from inlets at the base 18 of the frustoconical tip to spaced-apart
ports 19 in the rim 13 of the frustoconical tip.
The ports 19 provide means by which a gaseous material may be
jetted onto a feed stream of hydrocarbonaceous material emerging
from orifice 15. As illustrated, the grooves 17 are channeled in
face 16 of nozzle tip 14 to equal depth from the base 18 to the rim
13 of the tip so that the ports 19 are inclined with respect to the
discharge orifice at an angle within the range from about
30.degree. to about 75.degree.. It is preferred, but not necessary
to channel the grooves 17 in face 16 to equal depth from the base
18 to the rim 13 of tip 14 so that the grooves lay in the same
angle of taper as tip 14. In addition, each of the ports 19 is
axially oriented to the axis of the axial passageway 10 in the tube
at an angle within the range from about 0.degree. to about
90.degree.. FIGS. 4 and 6 illustrate an axial orientation for ports
19 of about 45.degree. with respect to the axis of the axial
passageway 10. FIG. 8 depicts a 0.degree. angle between the axis of
axial passageway 10 and the axes of ports 19. The ports 19 are
preferably disposed, as illustrated in FIGS. 4 and 6, tangentially
to orifice 15 so as to tangentially jet gaseous material from the
ports onto the stream of hydrocarbonaceous material as it emerges
from orifice 15 in order to shearingly whirl the hydrocarbonaceous
material about the axis of the axial passageway in atomizing the
hydrocarbonaceous material. The channels defined by the overlaying
portions of the internal surface of cap 20 and the overlaid grooves
17 in the frustoconical tip may extend from the base 18 to the rim
13 in a rectilinear manner, as in FIGS. 5-8, or in a curved manner,
as in FIGS. 3 and 4, so long as spacing is maintained between the
ports in the rim. The spiral configuration depicted in FIGS. 3 and
4, in which the grooves 17 are spiraled from base 18 to rim 13 of
tip 14 through one-fourth of a turn about the axial passageway 10,
is a preferred manner of tangentially disposing ports 19 relative
to rim 13 of the tip. A clockwise spiral is illustrated, but the
spiral may be counterclockwise. Frustoconical cap 20 surrounds the
ports 19 and the orifice 15 to shield and protect them from solids
in the coking zone which might otherwise land upon the ports and
the orifice from a peripheral or lateral direction.
Returning to FIG. 1, the external surface 23 of frustoconical cap
20 is tapered at a greater angle of taper than the angle of taper
of tip 14, the angle of taper defining the width of a lip 24 at the
intersection of the external wall 23 and internal wall 22, the
external wall taper angle preferably being chosen to minimize the
presence of lip 24. At the base of cap 20 between the surface 23
and internal surface 22 of the cap, an inner sleeve 25 is secured
by weldments. Inner sleeve 25 surrounds tube 11, thereby defining
an inner annular passageway, indicated by reference numeral 26,
between the sleeve 25 and tube 11. Inner annular passageway 26
terminates at the base 18 of the frustoconical tip 14 of tube 11 in
fluid communication with the spaced ports 19 by means of confined
channels 17. At the end of sleeve 25 opposite its attachment to cap
20, sleeve 25 is affixed by means of a closure flange 27 to the
periphery of tube 11. An inlet 28 is provided in sleeve 25 adjacent
closure flange 27 for admission of a gaseous temperature regulating
medium, preferably steam, into the inner annular passageway 26.
Inner sleeve 25 is mounted in a collar 29 fitted with an external
flange 29a which is assembled with a union clamp onto the base
flange 30 of a fixed outer sleeve 31 coaxially surrounding inner
sleeve 25 and affixed to the border of a cylindrical opening 32 in
the wall 33 of the vessel in which the coking reaction is carried
out. Outer sleeve 31 defines an outer annular passageway 34 between
it and inner sleeve 25. An inlet 35 is provided in outer sleeve 31
for introduction of gaseous material into the outer annular
passageway 34. Outer annular passageway 34 and inner annular
passageway 26 are not fluidly communicated. In the base of the
frustoconical cap 20, a plurality of confined gas conduits 36 are
provided which have inlets continuous with the outer annular
passageway 34 for receiving gaseous material and axial outlets 37
spaced apart in the base of the cap around the periphery of the
external surface 23 of the cap 20. The axial outlets 37 are axially
aligned, preferably at the angle of taper of the external surface
23, to converge on the axis of passageway 10 proximate the rim 13
of tip 14, as best viewed in FIG. 4, thereby to stream gaseous
material along the external surface 23 to wipe that surface free of
solids which are deposited on that surface from the coking zone in
the reactor.
Thus, in the embodiment pictured in the figures, a
hydrocarbonaceous feed is introduced into a confined axial
passageway 10 through an inlet 12 and passed through a
temperature-regulating zone maintained at a temperature lower than
the temperature of the coking zone by passage of a gaseous
temperature-regulating material, preferably steam introduced
through inlet 28, through inner annular passageway 26. The
temperature regulating material maintains the temperature of the
tube 11 at a temperature suitably below about 750.degree. F.,
preferably between about 600.degree. and 700.degree. F., to prevent
coking of the hydrocarbonaceous feed in its passage through tube 11
to discharge orifice 15, where the hydrocarbonaceous material is
discharged into the coking zone. The temperature regulating gaseous
material in inner annular passageway 26 flows under pressure into
the plurality of confined channels 17 in the nozzle tip, and thence
through spaced ports 19 onto the hydrocarbonaceous feed stream
emerging through discharge orifice 15 to atomize the feed stream
into a mist of droplets for spray dispersion in the coking vessel.
The gas jets preferably issue tangentially from ports 19 for
tangential impingement upon the feed stream exiting from discharge
orifice 15 to shearingly whirl the feed stream about the passageway
axis, by imparting centrifugal moments to the feed stream, thereby
effecting an improved spray in the coking zone. Inner annular
passageway 26 and confined channels 17 and ports 19 are fluidly
separated, i.e., not in fluid communication with outer annular
passageway 34 and fluid conduits 36 and outlets 37 so that the
gaseous temperature regulating materials cannot divert to outlets
37 if coke deposits momentarily lodge in spaced ports 19. As a
result, pressure builds in any spaced port 19 in which coke
particles do become lodged until the pressure is sufficient to
dislodge such particles, thereby providing self-cleaning of such
ports. The external surface 23 and lip 24 of the atomization nozzle
is wiped free of wetted solids from the coking zone by the play
thereon of wiping gaseous streams coaxially converged upon the
nozzle tip by passage through the confined conduits 36 after
passage through outer annular passageway 34, thus providing further
self-cleaning.
The mixing of the gases and the hydrocarbonaceous material after
the hydrocarbonaceous material emerges from the tip of the nozzle
prevents plugging of the axial passageway 10 by solids when mixed
solid and liquid phase hydrocarbonaceous feed is used.
The nozzle of this invention is adapted to be installed in any
position in a coking zone, vertically, horizontally etc. It can be
extended to any desired depth into the coking zone without coking
the feed in the feed passageway, which is kept below coking
temperatures by the temperature-regulating gaseous material in the
inner annular passageway surrounding the feed passageway.
In operation in spraying a hydrocarbonaceous feed into a fluid
coking zone, in which the hydrocarbonaceous feed rate extends over
a range from about 500 bbl./day per nozzle to about 1,000 bbl./day
per nozzle, a gas-to-hydrocarbonaceous feed specific volume ratio
of at least 1:1 is employed, preferably from about 1:1 to about
5:1. The hydrocarbonaceous feed rate and the
gas-to-hydrocarbonaceous feed specific volume ratio determine the
inside diameters of the feed tube and the gaseous channels which
terminate in the ports 19. For a 500 bbl./day per nozzle
hydrocarbonaceous feed rate, a 0.35-inch inner diameter may
satisfactorily be used. In this instance, a hydrocarbonaceous feed
velocity of from about 30 to about 100 ft./sec., e.g., about 40
ft./sec., through passageway 10 and a gaseous material velocity
through ports 19 of about 125 to about 250 ft./sec., e.g., about
150 ft./sec., may be utilized. For a hydrocarbonaceous feed rate of
about 1,000 bbl./day per nozzle, a 0.4-inch inner diameter for the
feed tube is satisfactory, permitting oil to be fed through the
tube passageway 10 at a velocity of about 110 ft./sec. and gas to
be fed through the confined channels and ports at a velocity of
about 250 ft./sec. The velocity ratio of the atomizing gas jets to
the discharging hydrocarbonaceous feed stream is suitably from
about 2 to about 4. The velocity of the spray discharged from the
tip of the nozzle will range from about 100 ft./sec. to about 250
ft./sec.
The hydrocarbonaceous material introduced into the feed tube is
preferably introduced at a temperature between about 600.degree.
and 700.degree. F. and is maintained at a temperature within the
tube of about 650.degree. and 700.degree. F. when passing through
the tube. Thus, the gaseous temperature regulating material in the
inner annulus is preferably steam heated to about 450.degree. F. A
steam rate of about 5- 30 lbs./hr. is sufficient to maintain this
temperature.
The following table, with reference to the drawing, summarizes
pertinent conditions in a preferred embodiment of the present
invention.
---------------------------------------------------------------------------
TABLE I
Broad Range Preferred Range
__________________________________________________________________________
Coking Zone
__________________________________________________________________________
Temperature of Incoming Solids, .degree.F. 1,000-1,350 1,150-1,200
Temperature in Coking Zone, .degree.F. 900-1,200 950-1,000
Pressure, p.s.i.g. 5-30 10-15 Avg. Solids Size, Microns 50-500
150-200 Density of Solids Suspension in Zone 15-60 35-45 Avg.
Residence Time of Solids in Zone, min. 10-60 15-30 Feed Nozzle
__________________________________________________________________________
Hydrocarbonaceous Feed Rate, bbl./day 5,000-60,000 15,000-50,000
Temperature of Hydro- carbonaceous Feed, .degree.F. 500-750 600-700
Gas/Hydrocarbonaceous Feed Specific Volume Ratio 1-5 1-3 Velocity
of Hydro carbonaceous Feed, ft./sec. 25-150 50-100 Velocity of
Atomizing Gas Jet, ft./sec. 100-350 200-300 Velocity of Wiping Gas
Streams, ft./sec. 50-150 75-125 Forward Velocity of Spray after
Dis- charge, ft./sec. 50-300 150-250
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Having described my self-cleaning system for spraying
hydrocarbonaceous materials into a fluid coking zone, and having
described a preferred embodiment for carrying out that system,
various embodiments for utilizing my system within the scope of the
appended claims will be apparent to those in the art.
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