U.S. patent application number 16/201867 was filed with the patent office on 2019-05-30 for fluid coking using high thrust feed nozzles.
The applicant listed for this patent is Syncrude Canada LTD. in trust for the owners of the Syncrude Project as such owners exist now and. Invention is credited to BRIAN KNAPPER, CRAIG McKNIGHT, JENNIFER McMILLAN, JASON WIENS, MICHAEL WORMSBECKER.
Application Number | 20190161684 16/201867 |
Document ID | / |
Family ID | 66634296 |
Filed Date | 2019-05-30 |
![](/patent/app/20190161684/US20190161684A1-20190530-D00000.png)
![](/patent/app/20190161684/US20190161684A1-20190530-D00001.png)
![](/patent/app/20190161684/US20190161684A1-20190530-D00002.png)
![](/patent/app/20190161684/US20190161684A1-20190530-D00003.png)
![](/patent/app/20190161684/US20190161684A1-20190530-D00004.png)
![](/patent/app/20190161684/US20190161684A1-20190530-D00005.png)
![](/patent/app/20190161684/US20190161684A1-20190530-D00006.png)
United States Patent
Application |
20190161684 |
Kind Code |
A1 |
McMILLAN; JENNIFER ; et
al. |
May 30, 2019 |
FLUID COKING USING HIGH THRUST FEED NOZZLES
Abstract
A process for converting a heavy hydrocarbonaceous feedstock to
liquid products is provided comprising introducing the
hydrocarbonaceous feedstock into a fluid coker comprised in part of
a fluidized bed of heated coke particles, the fluidized bed having
a high velocity core region of heated coke particles and a low
velocity annular region of unreacted hydrocarbon and coke particles
using a plurality of high thrust nozzles and reacting the
hydrocarbonaceous feedstock with the heated coke particles in the
fluid coker to produce the liquid products.
Inventors: |
McMILLAN; JENNIFER;
(Edmonton, CA) ; McKNIGHT; CRAIG; (Sherwood Park,
CA) ; WORMSBECKER; MICHAEL; (Edmonton, CA) ;
WIENS; JASON; (Edmonton, CA) ; KNAPPER; BRIAN;
(Edmonton, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Syncrude Canada LTD. in trust for the owners of the Syncrude
Project as such owners exist now and |
Fort McMurray |
|
CA |
|
|
Family ID: |
66634296 |
Appl. No.: |
16/201867 |
Filed: |
November 27, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62591678 |
Nov 28, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10G 9/005 20130101;
C10G 2300/1044 20130101; C10G 9/32 20130101 |
International
Class: |
C10G 9/32 20060101
C10G009/32; C10G 9/00 20060101 C10G009/00 |
Claims
1. A process for converting a heavy hydrocarbonaceous feedstock to
liquid products, comprising: introducing the hydrocarbonaceous
feedstock into a fluid coker comprised in part of a fluidized bed
of heated coke particles, the fluidized bed having a high velocity
core region of heated coke particles and a low velocity annular
region of unreacted hydrocarbon and coke particles; and reacting
the hydrocarbonaceous feedstock with the heated coke particles in
the fluid coker to produce the liquid products; the feedstock being
introduced into the fluid coker using a plurality of high thrust
nozzles, said nozzles designed to transport unreacted hydrocarbon
and coke from the low velocity annular region to the high velocity
core region to improve hydrocarbon stripping, reduce gas phase
residence time, and increase liquid products yields.
2. The process as claimed in claim 1, whereby the high thrust
nozzles have a spray angle of about 3.degree.-160.degree. and a
nozzle diameter between about 0.2'' and 0.8''.
3. The process as claimed in claim 1, wherein the high thrust
nozzle comprises a diverging section at the tip of the nozzle.
4. The process as claimed in claim 1, wherein the high thrust
nozzle comprises a converging section followed by a diverging
section at the tip of the nozzle.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a fluid coking process for
converting a heavy hydrocarbonaceous feedstock to liquid products
which uses high thrust feed nozzles for injecting feedstock into
the circulating fluidized bed of heated coke particles.
BACKGROUND OF THE INVENTION
[0002] Fluidized bed coking (fluid coking) is a petroleum refining
process in which heavy petroleum feeds, typically the
non-distillable residue (resid) from fractionation or heavy oils
are converted to lighter, more useful products by thermal
decomposition (coking) at elevated reaction temperatures, typically
about 480 to 590.degree. C., (about 900 to 1100.degree. F.) and in
most cases from 500 to 550.degree. C. (about 930 to 1020.degree.
F.). Heavy oils that may be processed by the fluid coking process
include heavy atmospheric resids, vacuum resids, aromatic extracts,
asphalts, and bitumen from oil sands.
[0003] The process is carried out in a unit with a large reactor
vessel containing hot coke particles that are maintained in the
fluidized condition at the required reaction temperature with a
fluidizing gas (e.g., steam) injected at the bottom of the vessel.
The heavy oil feed is heated to a pumpable temperature, typically
in the range of 350 to 400.degree. C. (about 660 to 750.degree.
F.), mixed with atomizing steam, and fed through multiple feed
nozzles arranged at several successive levels in the reactor. The
steam is injected into a stripper section at the bottom of the
reactor and passes upwards through the coke particles in the
stripper as they descend from the main part of the reactor above.
The feed liquid coats the coke particles in the fluidized bed,
which make up the emulsion phase of the fluidized bed. As the
thermal cracking reactions proceed, the liquid is transformed to
vapour, which must migrate from the emulsion phase into the bubble
phase in order to exit the system.
[0004] Liquid yields in fluid coking can be increased by reducing
the reaction severity, or the time that molecules are exposed to
process temperature. The typical approach taken to reduce reactor
severity is to reduce reactor temperature. However, the downside of
reducing temperature is increased stripper and sore thumb fouling,
which can lead to reduced run lengths. Another approach to reduce
reactor severity is to decrease the exposure time at high
temperatures by providing short vapour phase residence times.
[0005] Long hydrocarbon vapour residence times are the most likely
contributor to higher than expected "gas make", defined as
C.sub.4-components, in the fluid coking process. Vapour-liquid
equilibrium suppression, coupled with less than adequate mass
transfer between the emulsion and bubble phases, is the most
probable mechanism responsible for high "coke make", defined as the
toluene insoluble solid by-product of the thermal cracking
reaction. Both phenomena result in lower liquid yields, and
preliminary estimates suggest that they can contribute to as much
as 11 wt % liquid yield loss. Optimizing the rate of removal of
vapour from the emulsion phase should reduce the overall
hydrocarbon vapour residence time of the reactor, increase liquid
yields, and reduce gas make. It is estimated that a 3-5 wt % liquid
yield increase can be achieved through maximizing vapour recovery
from the reactor dense bed.
[0006] Technologies that increase mass transfer between the
emulsion and bubble phase and, thus, reduce the gas phase residence
time and increase hydrocarbon vapour stripping, are required.
SUMMARY OF THE INVENTION
[0007] It has been discovered that the reactor section of a fluid
coker is comprised of a dilute, upward-flowing stream of gas in the
central (core) region of the reactor and a dense, downward-flowing,
outer (annular) region of particles. This is due to the vaporized
hydrocarbons rising primarily in the core. Thus, the core region
has a high vapour and low solids concentration (solids lean) and
the annular region has a low vapour and high solids concentration
(solids dense).
[0008] The present invention is directed to the use of high thrust
feed nozzles to transport unreacted hydrocarbon and coke present in
the annular region of the fluidized bed to the high velocity core
region of the fluidized bed to improve hydrocarbon stripping,
reduce the gas phase residence time, and increase liquid yields.
Thrust is a mechanical force that is generated through the act of
accelerating a mass of fluid. In other words, it is the reaction
force created by the ejection of fluid from a nozzle at high
velocity. The fluid pressure is related to the momentum of the
fluid and acts perpendicular to any imposed boundary, which in this
case is the fluidized solids in the reactor. The amount of thrust
generated depends on the mass flow rate and the exit velocity of
the fluid. High thrust can be achieved by either slightly
accelerating a large mass of fluid, or greatly accelerating a small
mass of fluid.
[0009] Prior art nozzles that are presently used in fluid cokers
have a limited ability to transfer solids from the annular region
of the fluidized bed to the upward flowing core of the fluidized
bed. Thus, a process is provided herein for converting a heavy
hydrocarbonaceous feedstock to liquid products, comprising: [0010]
introducing the hydrocarbonaceous feedstock into a fluid coker
comprised in part of a fluidized bed of heated coke particles, the
fluidized bed having a high velocity core region of heated coke
particles and a low velocity annular region of unreacted
hydrocarbon and coke particles; and [0011] reacting the
hydrocarbonaceous feedstock with the heated coke particles in the
fluid coker to produce the liquid products; the feedstock being
introduced into the fluid coker using a plurality of high thrust
nozzles, said nozzles designed to transport unreacted hydrocarbon
and coke from the low velocity annular region to the high velocity
core region to improve hydrocarbon stripping, reduce gas phase
residence time, and increase liquid products yields.
[0012] In one embodiment, the high thrust nozzles have a spray
angle of about 3.degree.-160.degree. and a nozzle diameter between
about 0.2 and 0.8''.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the accompanying drawings:
[0014] FIG. 1 is a simplified diagram of the reactor of a fluid
coking unit useful in the present invention.
[0015] FIG. 2 shows the local pressure profiles along the length of
a GEN2 feed nozzle when air and water are sprayed into ambient air,
at air to liquid rations (ALRs) of 2.1 and 1.6 wt %.
[0016] FIG. 3 shows a drawing of a GEN3 feed nozzle having a
diverging cloverleaf disperser.
[0017] FIG. 4 shows a drawing of a GEN4 feed nozzle, which consists
of the same internal geometry as the GEN2 nozzle, but with slits at
the nozzle tip.
[0018] FIG. 5 is a graph comparing measured axial thrust force (lb)
with nozzle pressure (psig) for a variety of nozzles when spraying
water only.
[0019] FIG. 6 shows the local pressure profile along the length of
a Diffuser nozzle having a diverging/diffuser section when spraying
air and water into ambient air at ALRs of 2.6 and 1.7 wt %.
[0020] FIGS. 7A and 7B show the differences in the jet plume for
air-water mixtures exiting the GEN2 nozzle and the Diffuser nozzle,
respectively.
[0021] FIG. 8 shows a drawing of the GEN1 nozzle, which consists of
a simple constriction of 7.degree. followed by a 3'' long straight
section.
[0022] FIG. 9 is a graph of the measured axial thrust force (lb) as
a function of the measured nozzle pressure for a variety of nozzles
when spraying air and water.
[0023] FIG. 10 shows the local axial pressure profile along the
length of a GEN2 nozzle with an additional diverging section at the
exit when spraying air and water into ambient air at an ALR of 2.2
wt %.
DETAILED DESCRIPTION
[0024] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
embodiments of the present invention and is not intended to
represent the only embodiments contemplated by the inventor. The
detailed description includes specific details for the purpose of
providing a comprehensive understanding of the present invention.
However, it will be apparent to those skilled in the art that the
present invention may be practiced without these specific
details.
[0025] The present invention is directed to the use of high thrust
feed nozzles in a fluidized coking operation to push unreacted
hydrocarbon and coke to the high velocity core region of the
fluidized bed to improve hydrocarbon stripping, reduce the gas
phase residence time, and increase liquid yields.
[0026] Thrust is a mechanical force that is generated through the
act of accelerating a mass of fluid. In other words, it is the
reaction force created by the ejection of fluid from a nozzle at
high velocity (John and Keith, 2006). The fluid pressure is related
to the momentum of the fluid and acts perpendicular to any imposed
boundary, which in this case is the fluidized solids in the
reactor. The amount of thrust generated depends on the mass flow
rate and the exit velocity of the fluid. High thrust can be
achieved by either slightly accelerating a large mass of fluid, or
greatly accelerating a small mass of fluid.
[0027] There are three main factors that affect thrust: friction
effects, axial momentum loss and thrust loss due to the pressure
difference between the nozzle exit plane and the background. When
friction is considered, it is best to have nozzles with large exit
angles. However, the axial momentum losses increase as the angle
increases since a higher percentage of the exiting flow will be
non-axial.
[0028] Cruz (Cruz, N., "Interactions between Supersonic Gas Jets
and Gas-Solid Fluidized Beds", MSc Thesis, The University of
Western Ontario, 2009) found that the thrust force of gas in a
convergent-divergent nozzle used to attrition particles in a
fluidized bed had a strong relationship with the particle grinding
efficiency. During the attrition process, particles are entrained
into the gas jet and are accelerated to high velocity where they
collide with the particles in the dense phase of the fluidized bed
at the tip of the jet plume and cause particle breakage to occur.
This concept can be used to enhance the movement of solids from the
annular section of the reactor to the core region in the feed zone
by using feed nozzles that produce a high thrust force.
[0029] FIG. 1 is a simplified diagram of the reactor of a fluid
coking unit. The reactor coking zone 10 contains a fluidized bed 11
of heated seed coke particles, heated to a temperature sufficient
to initiate the coking (thermal cracking) reactions, into which the
feedstock is added. The feedstock contacts the coke particles and
reacts, and deposits a fresh coke layer on the hot fluidized coke
particles circulating in the bed. The fluidized bed of coke
comprises a dense bed surface 34, which is static, a dilute core
region 32, which is upward flowing, and a dense annular region 30,
which is downward flowing.
[0030] The feed is injected through multiple high thrust nozzles
located in feed rings 12a to 12f, which are positioned so that the
feed with atomizing steam enters directly into the fluidized bed of
hot coke particles in coking zone 11. Each feed ring consists of a
set of high thrust nozzles (typically 10-20, not designated in FIG.
1) that are arranged around the circular periphery of the reactor
wall at a given elevation with each nozzle in the ring connected to
its own feed line which penetrates the vessel shell (i.e. 10-20
pipes extending into the fluid bed). These high thrust feed nozzles
are typically arranged non-symmetrically around the reactor to
optimize flow patterns in the reactor according to simulation
studies although symmetrical disposition of the nozzles is not
precluded if the flow patterns in the reactor can be optimized in
this way. There are typically 4-6 feed rings located at different
elevations although not all may be active at any one time while the
unit is working.
[0031] Steam is admitted as fluidizing gas in the stripping section
13 at the base of coker reactor 10, through spargers 14 directly
under stripping sheds 15 as well as from lower inlets 16. The steam
passes up into stripping zone 13 of the coking reactor in an amount
sufficient to obtain a superficial fluidizing velocity in the
coking zone, typically in the range of about 0.15 to 1.5 m/sec
(about 0.5 to 5 ft/sec). The coking zone is typically maintained at
temperatures in the range of 450 to 650.degree. C. (about 840 to
1200.degree. F.) and a pressure in the range of about 0 to 1000
kPag (about 0 to 145 psig), preferably about 30 to 300 kPag (about
5 to 45 psig), resulting in the characteristic conversion products
which include a vapor fraction and coke which is deposited on the
surface of the seed coke particles.
[0032] The vaporous products of the cracking reactions with
entrained coke particles pass upwards out of the reaction zone 11,
through a phase transition zone in the upper portion 17 of the
vessel and finally, a dilute phase reaction zone at the inlets of
cyclones 20 (only two shown, one indicated). The coke particles
separated from the vaporous coking products in the cyclones are
returned to the fluidized bed of coke particles through cyclone
dipleg(s) 21 while the vapors pass out through the gas outlet(s) 22
of the cyclones into the scrubbing section of the reactor (not
shown). After passing through scrubbing section which is fitted
with scrubbing sheds in which the ascending vapors are directly
contacted with a flow of fresh feed to condense higher boiling
hydrocarbons in the reactor effluent (typically 525.degree.
C.+/975.degree. F.+) and recycles these along with the fresh feed
to the reactor. The vapors leaving the scrubber then pass to a
product fractionator (not shown). In the product fractionator, the
conversion products are fractionated into light streams such as
naphtha, intermediate boiling streams such as light gas oils and
heavy streams including product bottoms.
[0033] The coke particles that pass downwards from the dense bed 11
to stripper section 13 comprising sheds 15 are partially stripped
of occluded hydrocarbons in the stripper by use of a stripping gas,
usually steam, which enters via spargers 14. The stripped coke
particles are passed via line 25 to a heater (not shown) which is
operated a temperature from about 40 to 200.degree. C., preferably
about 65 to 175.degree. C., and more preferably about 65 to
120.degree. C. in excess of the actual operating temperature of the
coking zone and recycled back to the fluid coking unit.
Example 1
[0034] Current commercial fluid coking feed nozzles are designed to
atomize the bitumen at the nozzle exit through shear from the high
velocity and rapid decompression of the atomization steam upon
exiting the nozzle. This decompression happens both axially and
radially.
[0035] One such coker nozzle is described in detail in Canadian
Patent No. 2,224,615, and is referred to herein as TEBM-2b with
circular exit, or GEN2 nozzle. The GEN2 nozzle consists of a series
of converging, diverging, and converging sections. The pressure
drop across the exit of the GEN2 coker feed nozzle is on the order
of 70 psi. The flow exiting the nozzle consists of bubbles
dispersed in the liquid phase and the large decompression from the
resultant pressure drop at the exit causes an explosive expansion
of the bubbles, resulting in a phase inversion where the flow
changes from liquid continuous in the nozzle to gas continuous in
the jet, with liquid droplets and ligaments distributed in the gas
stream.
[0036] FIG. 2 shows the local pressure profiles along the length of
a GEN2 feed nozzle when air and water are sprayed into ambient air,
at air to liquid ratios (ALRs) of 2.1 and 1.6 wt %. The increase in
pressure along the diverging section of the nozzle is consistent
with subsonic flow. FIG. 2 shows a significant pressure drop at the
exit of the nozzle, which causes the gas to expand rapidly in both
the axial and radial direction.
[0037] In this example, the GEN2 nozzle and the 1.25GEN2, which is
the same as the GEN2 nozzle except all of the dimensions are scaled
up so that the throat area is 25% larger than the GEN2 nozzle, were
tested in order to measured axial thrust force (lb) as a function
of the nozzle pressure. In addition to the GEN2 nozzles, three
commercially available fan spray nozzles, referred to herein as
Nozzle B, Nozzle C and Nozzle D, and a curved throat fan nozzle
used in the FCC process, described in detail in U.S. Pat. No.
6,199,768, referred to herein as CTF, were tested in this example.
A GEN3 nozzle, which consists of the same internal geometry as the
GEN2 nozzle but contains a diverging cloverleaf disperser at the
tip of the nozzle, was also tested. A drawing of a GEN3 nozzle is
shown in FIG. 3 and described in more detail in U.S. Pat. No.
8,999,246. 1.1GEN3 and 1.25GEN3 nozzles are the same as the GEN3
nozzle, but all of the dimensions are scaled up so that the throat
area is 10% and 25% larger than the GEN3 nozzle, respectively.
[0038] Finally, FIG. 4 shows a drawing of a GEN4 nozzle, which
consists of the same internal geometry as the GEN2 nozzle but with
slits at the nozzle tip. The GEN 4 nozzle is described in more
detail in U.S. Pat. No. 9,889,420. The 1.1GEN4 is the same as the
GEN4 nozzle, but all of the dimensions are scaled up so that the
throat area is 10% larger than the GEN4 nozzle.
[0039] Experiments were conducted with the aforementioned feed
nozzles having different equivalent throat diameters and exit
angles by spraying water into open air over a range of liquid flow
rates and nozzle pressures. Table 1 shows a summary of the nozzles
that were tested and their specifications. The nozzles were mounted
on a stand that allowed them to move freely in the axial direction.
The reaction thrust force was measured using a 3000 lb thru-hole
compression load cell, which was mounted on the nozzle conduit and
was compressed between two plates while the nozzle was
spraying.
TABLE-US-00001 TABLE 1 Summary of Nozzle Specifications Tested with
Water Throat Diameter Spray Angle Nozzle Description (inches)
(.degree.) Nozzle B Fan spray nozzle 0.344 50 Nozzle C Fan spray
nozzle 0.297 65 Nozzle D Fan spray nozzle 0.297 120 GEN2 TEBm-2b*
with circular exit 0.512 11 GEN3 TEBm-2b* with cloverleaf 0.512 23
disperser 1.1GEN3 TEBm-2b* with cloverleaf 0.537 23 disperser
1.25GEN3 TEBm-2b* with cloverleaf 0.572 23 disperser CTF Curved
throat fan nozzle 0.27 40 1.1GEN4 TEBm-2b* with four slits in the
0.557 50 exit *Base et al. (1999)
[0040] FIG. 5 shows a plot of the measured axial thrust force (lb)
as a function of the nozzle pressure for the various nozzle
geometries. The axial thrust force was highly correlated with the
nozzle pressure. FIG. 5 shows that nozzles that provide the same
nozzle pressure, with the same exit area, operating at the same
liquid flow rate, result in different axial thrust measurements due
to the difference in nozzle geometry. For example, Nozzle C and
Nozzle D both have an orifice diameter of 0.297'', however, Nozzle
C produces a spray with an angle of 65.degree., whereas Nozzle D
produces a spray with an angle of 120.degree. and when operating at
a nozzle pressure of 400 psig. The measured axial thrust force of
Nozzle C was approximately 10 lb greater than the measured axial
thrust force of Nozzle D. The larger spray angle resulted in a
smaller axial thrust force as more of the thrust force was directed
in the radial direction. Nozzles B-D are BETE nozzles designed to
be operated with liquid only and, therefore, produced higher thrust
forces than the GEN2, GEN3, GEN4 and CTF nozzles, which are
designed to be operated with both gas and liquid. However, even
when operating with only liquid, noticeable differences in the
thrust force were observed with changes in nozzle geometry. For
example, the GEN2 and GEN3 nozzles have the same exit orifice
diameter, and when operating at a fluid pressure of 157 psig the
GEN3 nozzle, which has a diverging nozzle exit, resulted in an
axial thrust force that was approximately 7 lbs greater than the
axial thrust force of the GEN2 nozzle that has a converging nozzle
exit.
[0041] In summary, the results in FIG. 5 show that the thrust force
is highly correlated with the fluid pressure upstream of the
nozzle. In addition, nozzle spray angles and exit geometries can be
optimized to produce higher thrust forces.
Example 2
[0042] In order to maximize the axial thrust force and reduce the
expansion of the jet in the radial direction, a supersonic nozzle
with a diverging/diffuser section was designed to accelerate the
fluid axially in the nozzle exit, prior to injection into the
fluidized bed (hereinafter referred to as the "Diffuser nozzle").
The Diffuser nozzle consists of the same internal geometry as the
GEN2 nozzle but without the final constriction at the nozzle tip.
The diffuser section now resulted in a much narrower jet plume. The
phase inversion occurs within the nozzle, and the fluid
acceleration through the nozzle will increase in the axial
direction. In addition, a supersonic nozzle maximizes the velocity
of the jet at a much larger cross sectional exit area compared to a
subsonic nozzle.
[0043] FIG. 6 shows the local pressure profile along the length of
a Diffuser nozzle when spraying air and water into ambient air at
ALRs of 2.6 and 1.7 wt %. The pressure decrease along the diverging
section of the nozzle indicates that the flow is supersonic. It can
be seen that the fluid exits the nozzle at the same pressure as the
ambient air, which reduces thrust loss and results in minimum
radial expansion.
[0044] FIGS. 7A and 7B are photographs showing the differences in
the jet plume for air-water mixtures exiting the GEN2 nozzle (FIG.
7A) and the Diffuser nozzle (FIG. 7B). The images clearly show that
the spray plume is much narrower with the Diffuser nozzle, since
all of the driving pressure has been used to accelerate the flow in
the axial direction.
[0045] Experiments were conducted using feed nozzles with different
equivalent throat diameters and exit geometries by spraying air and
water into open air over a range of liquid flow rates and nozzle
pressures. Table 2 shows a summary of the nozzles that were tested
and their specifications. The nozzles were mounted on a stand that
allowed them to move freely in the axial direction. The reaction
thrust force was measured using a 3000 lb thru-hole compression
load cell, which was mounted on the nozzle conduit and was
compressed between two plates while the nozzle was spraying.
TABLE-US-00002 TABLE 2 Summary of Nozzle Specifications for Nozzles
Tested with Air and Water Throat Diameter Nozzle Description
(inches) Exit Geometry GEN1 Simple constriction with 0.512
Converging with long circular exit circular exit GEN2 TEBm-2b with
circular exit 0.512 Converging with circular exit GEN3 TEBm-2b with
cloverleaf 0.512 Diverging with disperser cloverleaf shaped exit
1.25GEN2 TEBm-2b with circular exit 0.572 Converging with circular
exit 1.25GEN3 TEBm-2b with cloverleaf 0.572 Diverging with
disperser cloverleaf shaped exit Diffuser Constriction followed by
0.516 Diverging with long diffuser circular exit 1.2Diffuser
Constriction followed by a 0.562 Diverging with long diffuser
circular exit 1.5Diffuser Constriction followed by a 0.628
Diverging with long diffuser circular exit
[0046] A drawing of a GEN1 nozzle is shown in FIG. 8 and consists
of a simple constriction of 7.degree. followed by a 3'' long
straight section. The 1.2Diffuser nozzle and 1.5Diffuser nozzle are
the same as the Diffuser nozzle shown in FIG. 6, but all of the
dimensions are scaled up so that the throat area is 20% and 50%
larger than the Diffuser nozzle, respectively.
[0047] FIG. 9 shows a plot of the measured axial thrust force (lb)
as a function of the measured fluid pressure. The axial thrust
force was highly correlated with the fluid pressure. FIG. 9 shows
that nozzles that provide the same fluid pressure, with the same
throat diameter result in different axial thrust measurements due
to the differences in nozzle geometry. For example, the GEN1, GEN2
and GEN3 all have the same throat diameter, however, at a nozzle
pressure of 275 psig, the measured axial thrust force of the GEN3
nozzle was approximately 11 lb greater than the GEN2 nozzle and 14
lb greater than the GEN1 nozzle. The diverging cloverleaf disperser
located on the tip of the GEN3 nozzle reduces the radial expansion
of the fluid and results in a higher axial thrust force. The
nozzles that provide the largest axial thrust force are the
1.5Diffuser and the 1.2Diffuser. These nozzles have a larger throat
and have a long diffuser section located at the end of the nozzle,
which results in a decrease in pressure along the nozzle outlet,
which means that supersonic velocities are achieved. The axial
thrust through these nozzles has been maximized since the pressure
at the nozzle exit is equal to the ambient pressure and therefore,
all of the driving pressure has been used to accelerate the flow in
the axial direction.
Example 3
[0048] Another nozzle geometry that would maximize the axial thrust
force would be to add a diverging section to the GEN2 nozzle in
order to accelerate the fluid to supersonic velocities before
exiting the nozzle. FIG. 10 shows the local axial pressure profile
along the length of a GEN2 nozzle with an additional diverging
section at the exit when spraying air and water into ambient air at
an ALR of 2.2 wt %. The pressure along the outlet diffusing section
decreases, indicating that supersonic velocities were achieved. The
axial thrust through this nozzle has been maximized since the
pressure at the nozzle exit is equal to the ambient pressure and
therefore all of the driving pressure has been used to accelerate
the flow in the axial direction.
[0049] From the foregoing description, one skilled in the art can
easily ascertain the essential characteristics of this invention,
and without departing from the spirit and scope thereof, can make
various changes and modifications of the invention to adapt it to
various usages and conditions. Thus, the present invention is not
intended to be limited to the embodiments shown herein, but is to
be accorded the full scope consistent with the claims, wherein
reference to an element in the singular, such as by use of the
article "a" or "an" is not intended to mean "one and only one"
unless specifically so stated, but rather "one or more". All
structural and functional equivalents to the elements of the
various embodiments described throughout the disclosure that are
known or later come to be known to those of ordinary skill in the
art are intended to be encompassed by the elements of the claims.
Moreover, nothing disclosed herein is intended to be dedicated to
the public regardless of whether such disclosure is explicitly
recited in the claims.
* * * * *