U.S. patent number 3,708,419 [Application Number 05/087,551] was granted by the patent office on 1973-01-02 for self-cycling fluid heater.
Invention is credited to George M. Deputy Administrator of the National Aeronautics and Space Low, Walter K. Moen, N/A.
United States Patent |
3,708,419 |
Low , et al. |
January 2, 1973 |
SELF-CYCLING FLUID HEATER
Abstract
The specification discloses a self-cycling fluid heater
including a high temperature upstream preheater for elevating the
stream temperature, a high intensity jet arc heater which heats the
preheated fluid stream to ultra high reaction temperatures and
discharges said stream into an electric resistance tubular heat
exchanger having variations in wall thickness at measured intervals
along its length to precisely control the temperature of the fluid
passing through such heat exchanger for desired time intervals to
provide the specified chemical reactions desired.
Inventors: |
Low; George M. Deputy Administrator
of the National Aeronautics and Space (N/A), N/A
(Newport Beach, CA), Moen; Walter K. |
Family
ID: |
22205843 |
Appl.
No.: |
05/087,551 |
Filed: |
November 6, 1970 |
Current U.S.
Class: |
422/186.25;
219/383; 392/469 |
Current CPC
Class: |
F24H
1/0045 (20130101); F24H 1/101 (20130101) |
Current International
Class: |
F24H
1/10 (20060101); C22d 007/08 () |
Field of
Search: |
;204/323-328 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mack; John H.
Assistant Examiner: Tufariello; T.
Claims
I claim:
1. A self-cycling heater for heating liquids to ultra high
temperatures comprising:
a. a housing having a high temperature refractory body forming a
reaction chamber therein,
b. a liquid inlet chamber in said refractory body communicating
said reaction chamber,
c. a liquid discharge chamber in said refractory body communicating
said reaction chamber,
d. positive and negative electrodes in said reaction chamber for
forming an electric arc therein for heating liquid flowing
therethrough,
e. preheater means connected to said liquid inlet chamber for
heating the liquid prior to introduction into said reaction
chamber, and
f. downstream reaction heat exchanger means connected to said
liquid discharge chamber for controlling the temperature of said
liquid during a controlled reaction.
2. The invention of claim 1 wherein said preheater and said
downstream reaction heat exchanger comprise tubular electrical
resistance heaters.
3. The invention of claim 2 wherein said tubular electrical
resistance heaters are provided with walls whose thickness varies
according to the temperature desired in each portion of the tubular
heater.
4. The invention of claim 2 in which the length of the various
portions of the tube of a given wall thickness varies according to
the resident time of the liquid flowing therethrough.
5. The invention of claim 2 wherein said tubular electric
resistance pre-heater is coiled around said inlet chamber and said
downstream control heat exchanger coiled around said discharge
chamber.
6. The invention of claim 1 including a restricted throat in said
fluid inlet chamber for increasing the velocity of liquid entering
said reaction chamber.
7. The invention of claim 1 including conduit means extending
radially outwardly from adjacent said reaction chamber to the
exterior of said refractory body and means for injecting fluid into
said conduit means for removing particles of the electrodes from
said fluid stream.
8. The invention of claim 7 wherein said high temperature
refractory body is surrounded by annular chambers and said conduit
means communicates with said annular chambers.
9. The invention of claim 7 including a pair of concentric annular
chambers around said body, with said conduit means connecting the
innermost of said annular chambers with said reaction chamber;
passages connecting the inner and outer annular chambers; and
exhaust means in said outer annular chamber for discharging fluid
therefrom.
10. The invention of claim 1 including port means in said
refractory body adjacent said reaction chamber for injecting
catalyst into said reaction chamber for mixture with liquids
entering said reaction chamber from said inlet chamber.
11. The invention of claim 1 wherein the electrodes are truncated
cones aligned side by side to provide maximum linear contact.
12. The invention of claim 1 wherein said electrodes comprise flat
plates which are stacked one on top the other with insulating means
therebetween and which are operated by alternating current to
provide a long electrode arc.
13. The invention of claim 1 wherein said electrodes have rounded
sides and are arranged side by side to provide a linear arc.
14. The invention of claim 1 wherein said refractory body is formed
of aluminum oxide.
15. The invention of claim 1 wherein said refractory body comprises
a material suitable for combustion as an element in the desired
chemical reaction and which is expendable in the chemical reaction.
Description
ORIGIN OF THE INVENTION
The invention described herein was made in the performance of work
under a NASA contract and is subject to the provisions of Section
305 of the National Aeronautics and Space Act of 1958, Public Law
85- 568 (72 Stat. 435; U.S.C. 2457).
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to a self-cycling fluid heater for
heating a continuous fluid stream having a jet arc heater for
heating fluids and gases to ultra high temperatures, such as
3,000.degree. to 5,000.degree. in an arc crater which discharges
into a tubular heat exchanger precisely controlled to specific
temperatures for desired resident times to facilitate the desired
petro-chemical or other chemical reactions in the flowing
stream.
2. Description of the Prior Art
The prior art includes patents to Rouy U.S. Pat. No. 2,684,329
issued July 20, 1954 for a Method and Apparatus for Promoting
Chemical Reaction, and U.S. Pat. No. 3,003,939 issued Oct. 10, 1961
for a Method and Apparatus for Producing and Enhancing Chemical
Reaction in Flowable Reactant Material. The first of such patents
discloses an apparatus for promoting chemical reaction wherein a
heated fluid travels through a pipe and is subjected to an electric
field, and particularly through an alternating electric field
producing a wide range of graduated intensities to provide a zone
of optimum electron velocity. Whereas, the second Rouy patent
discloses an apparatus and method for effecting chemical reaction
in a reacting zone positioned in an electric field in conjunction
with a venturi nozzle to control the pressure, temperature, and
velocity of a flowable reaction material to favor a particular
desired reaction.
There has long been recognized the need for improved high
temperature processing tools and the advantages to be derived from
high-intensity arc heaters and their ability to activate a solid
phase for reaction. For example, the following publications
recognize the need for such devices:
"Development and Possible Application of Plasma and Related
High-Temperature Generating Devices" Report MAB-167-M Division of
Engineering and Industrial Research, National Academy of Sciences,
National Research Council, Washington, D. C. (August 30, 1960).
"Trends in High-Temperature Chemical Processing" Part 1 Chemical
Engineering March 14, 1966.
Also, there is a recognized need for precise control of the
duration and intensity of heat applied to a reaction stream for
controlling or providing a desired chemical reaction. The present
invention presents a novel means for reclamation of chemicals from
polluted surface water, particularly hydrocarbon waste. By heating
a continuous flowing stream of polluted water to a high reaction
temperature, as made possible by the apparatus of the present
invention, hydrocarbon waste may be extracted from the polluted
stream.
SUMMARY OF THE INVENTION
Briefly, the present invention provides a self-cycling fluid heater
comprising a tubular pre-heater, a high intensity direct arc-jet
heater, and a downstream reaction heat exchanger in which the
temperature of the reaction fluid is precisely controlled. It is an
object of the present invention to provide a new and improved
self-cycling fluid heater incorporating a high intensity arc-jet
with a pre-heater and a downstream reaction heat exchanger wherein
the high intensity arc-jet includes carbon electrodes which provide
an arc for heating a fluid stream to the range of 3,000.degree. to
5,000.degree. F. and discharging the fluid into the tubular heat
exchanger for a controlled reaction of such heated fluid. The
preheater tube as well as the control reaction heat exchanger tube
is chemically milled internally to facilitate self-cycling of
fluids in the system.
Another object of the present invention is to provide a new and
improved self-cycling heater in which heat from the high intensity
arc-jet heats the fluid in a shaped container to cause the fluid to
flow through the pre-heater and also the downstream reaction heat
exchanger. Such invention also includes means for injecting gas
into the arc crater to effect the desired reaction.
It is also an object of the present invention to provide a high
intensity jet arc heater having means to separate particles from
spent carbon electrodes from the fluid stream and also having a
tubular reaction heat exchanger wherein such tubes are loosely
supported intermediate their extreme ends to facilitate expansion
and vibration of such tubular elements during operation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view of a cylindrical heater
housing showing the pre-heater coil, the jet-arc crater, and the
downstream reaction heat exchanger of the present invention;
FIG. 2 is a sectional view showing a sandwich-type electrode for
use in the jet-arc heater of the present invention;
FIG. 3 shows truncated electrodes;
FIG. 4 is a view of a portion of a typical coil showing the
internal construction thereof;
FIG. 5 is a sectional view of a straight heater tube having a
helical internal configuration;
FIG. 6 is a sectional view of another straight heater tube having
hot control zones;
FIG. 7 is a sectional view showing a straight heater tube having
graduated internal sections for controlling the heat of fluid
thereto and causing turbulence in the flow of such fluids;
FIG. 8 is a schematic view of a self-cycling fluid heater of the
present invention shown in conjunction with a petro-chemical
production reclamation facility.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The self-cycling fluid heater apparatus of the present invention is
designated generally as S in FIG. 1 of the drawings. Such heater S
includes a housing H having a pre-heater coil P for pre-heating the
reacting fluid, a jet-arc reaction chamber J in which a high
intensity arc-jet heats such pre-heated fluid to ultra high
reaction temperatures such as 3,000.degree. to 5,000.degree. F. and
discharges such superheated fluids into a downstream control
reaction heat exchanger D where the desired chemical reaction is
controlled. The ultra high temperature is created by the arc crater
designated generally A which spans the gap between the ends of two
carbon electrodes E and F, respectively, which are positioned in
the reaction chamber J. The reaction fluid is circulated through
the pre-heater P where its temperature is elevated to a desired
temperature and thereafter it is injected into the reaction chamber
J and subjected to the ultra high intensity arc-jet and thereafter
such fluid and gas resulting from the high temperature is conducted
through the control reaction heat exchanger D where the controlled
chemical reactions are produced.
In the preferred form of the present invention, as shown in FIG. 1
of the drawings, the housing H includes an outer cylindrical wall
11 having end closure members 12 and 13, respectively. As shown, a
pair of radially inwardly spaced cylindrical walls 15 and 16 which
are disposed concentrically inwardly relative to the outer
cylindrical wall 11 are provided in the housing H and form annular
chambers 17 and 18, respectively. The inner cylindrical wall 16
connects both ends 12 and 13, respectively, and the intermediate
cylindrical wall 15 connects the end 12 but is spaced laterally
from the end 13 to provide a passage for circulating fluid
therethrough which will be described in detail hereinafter. Also,
as shown, a plurality of openings or passages 15a are provided in
the intermediate wall 15 to afford communication between the inner
annular chamber 17 and the outer annular chamber 18.
As shown, an inlet conduit 20 is connected to the pre-heater coil,
P which comprises a plurality of turns of tubular conduit which is
made of corrosion resistant steel, nickel, platinum, tantalum,
rhodium, silver, brass, aluminum, copper, wrought-iron, lead, or
alloys of a wide variety. Also, it will be appreciated that the
pre-heater could consist of a bank of coiled or straight tube
heaters manifolded together to increase flow capacity.
The reaction control heat exchanger D is formed similarly to the
pre-heater P and is provided with an outlet 21 for discharging
fluids and gases from such heat exchanger after the desired
chemical reactions have accrued. The tubular heater P as well as
the reaction heat exchanger D are shown surrounded by super-X high
temperature insulation 24 which is preferably a loose insulation
material that does not restrict the motion of the tubular heater P
or heat exchanger D under pressure and permits vibration of such
tubular sections to thereby increase the heat transfer coefficient
thereof. The inlet 20 is shown connected to the first turn 20a of
the tubular heater P and the last turn 20b is connected to a port
20c formed in the reaction chamber J as will be described in detail
hereinafter. Similarly, the control reaction heat exchanger D has
its innermost turn 25 connected to the port 26 in the reaction
chamber J and the outermost turn 27 is connected to the discharge
conduit 21.
The body of the high intensity reaction chamber J is preferably
formed of a high temperature (3,300.degree. F) castable refractory,
graphite (ATJ, JTA or prolytic) or a water cooled reaction chamber
is provided for higher temperatures. Such reaction chamber body is
preferably formed of a generally cylindrical outer central portion
28 of substantially the same diameter as the inner diameter of the
innermost wall 16 and having restricted diameter axial end portions
30 and 31, respectively, which project axially of the coil tubular
heater P heat exchanger D, respectively. It will be appreciated
that the material from which the body of the reaction chamber is
formed, in addition to being a high temperature castable, material,
may also assist the reaction of the fluids therein by proper
material selection of the chamber walls which may be expendable to
the overall operation of the heater.
The reaction chamber J is preferably formed by using a pre-formed
wax or glass container which may be melted or cracked out for
shaping the chamber with the desired internal configuration. As
shown, such reaction chamber is formed with a discharge chamber 35
positioned in the end 31 and an inlet chamber 37 is axially aligned
with the inlet chamber and positioned in the opposite end 30. Such
discharge chamber 35 has a substantially flat end portion 35a with
a generally circular wall 38 extending longitudinally toward the
center of such reaction chamber J. The walls 38 of the reaction
chamber J flare or curve radially outwardly from adjacent their
inner end 38a toward the inner cylindrical wall 16 to form a curved
or flared surface indicated at 41.
As shown, the inlet chamber 37 adjacent the reaction chamber J is
provided with a substantially flat end 42 and a cylindrical wall 43
which curves or tapers inwardly at 44 to form a throat or
restricted neck 45. Thereafter, such side wall flares upwardly and
outwardly toward the opposite curved walls 41 to provide a
circumferentially extending restricted, outer throat or passage
extending circumferentially of the chamber J and outwardly to a
circumferentially extending slit or port 45 in the wall 16 so as to
communicate the chamber J with the outer annular chambers 17 and
18. As shown, a circular recess 48 surrounds the cylindrical
chamber 38 adjacent the curved end portion 44 to form a
circumferentially extending tubular lip or flange 49 that forms an
inner throat of passage 50 which is disposed between the arc crater
area A and the outer throat 44.
A plurality of circumferentially spaced jets 52 are positioned in
the annular recess 48 for discharging steam or gas into the
narrowed restricted throat or passage 44 for urging gas and
particles formed in the arc-jet crater A outwardly through the
ports 45. A suitable gas injection port 54 is preferably formed in
the reaction chamber housing adjacent the arc-jet crater A for
injecting gas or a catalyst adjacent the temperature in such
arc-jet crater.
As shown, the arc-jet crater is positioned adjacent the facing ends
of the electrodes E and F which are carried in the housing H in
suitable electric bushings 60 that extend through openings in the
wall 11 as well as the inner and intermediate walls 16 and 15,
respectively. Preferably, the positive electrode F is a consumable
electrode which is mechanically advanced into the arc crater. Such
electrodes are operated preferably by a motor generator using
direct current so that the consumable electrode F receives more
heat by electron bombardment. Such consumable electrode normally
operates in the area of 3,000.degree.F. to 5,000.degree.F. and
above where it vaporizes. Carbon particles are ejected from the arc
crater by the influence of the passage 44 provided by the steam
injector nozzles 52 which inject steam through the passage 44 to
draw particles through the passage 50. Such carbon particles are
separated from the reaction gas and collected in the concentric
chambers 17 and 18 and such gas is filtered and exits the chambers
through the passage 19.
In operation, fluid is introduced into the tubular pre-heater P via
the inlet 20 where such fluid is heated to a desired amount as will
be described in detail hereinafter. Such fluid is discharged from
the preheaters through the port 20c into the reaction chamber J.
Such preheated fluid flows through the throat 45 to the arc crater
area A where such fluid or gas is heated to an ultra high
temperature and thereafter such heated fluid passes into the
chamber 35 and is discharged through the port 26 into the
controlled reaction heat exchanger D. There the temperature of such
superheated fluid is maintained at a desired temperature for a
desired period of time to provide the necessary reaction of the
heated fluid or gas. Steam is injected through the lateral ports 52
adjacent the arc crater area A for causing the carbon particles
from the electrodes to pass laterally outwardly into the concentric
chambers 17 and 18 where they settle out or are filtered out from
the gas and bypass gas carrying such particles is then discharged
through the outlet port 19. Other gases or desired elements may be
introduced into the arc crater via the inlet port 54 for combining
with the fluid or gas in such arc crater for subsequent processing
in the controlled reaction heat exchanger.
In operation, the current to the arc crater A is increased to a
point where vaporization of the consumable electrode F reaches a
heat balance most desirable for the particular chemical reaction.
When operating the high intensity arc, the consumable electrode F
is mechanically advanced into the arc crater A where the energy
transfer occurs at high energy transfer efficiencies. This
condition is ideal for chemical synthesis when assisted by
downstream reaction heater D to maintain a desirable reaction
temperature of a constant flowing end product useful gas.
FIG. 8 presents a schematic of a typical self-cycling fluid heater
arrangement shown associated with conventional processing
components. A three-way valve 65 controls the flow through a steam
inlet line 71, a material inlet line 72, and a reactant gas inlet
line 73 into the pre-heater P through a thermal valve 75. Such
fluids are mixed at an elevated temperature in the pre-heater P as
monitored by the thermal valve 75 which controls the alternating
current supply to the saturable core reactor controller 76 that
provides heat to the preheater P. The flow of fluids out of the
pre-heater P to the jet-arc crater in the housing 79 is through a
suitable conduit 80 having a regulator valve 82 therein which
functions as a pressure valve associated with the electrical
equipment as described hereinafter to provide a safety shut-off
apparatus in the event of malfunction of the system. A constant
pressure regulator 85 is associated with the conduit 80 for
controlling the flow of gas to the high intensity arc in the crater
chamber 79. Motor generator 90 supplies current to the electrodes
in the jet-arc crater 79. Steam or other gases may also be supplied
to the crater by means of the conduit 91 which introduces fluid
into the jet-arc crater through a port or opening 54. The reacting
gases leave the arc crater 79 where further mixing occurs at the
downstream port prior to entrance to the downstream reaction
control heat exchanger designated generally D which provides a
precise control to the final product gas passing outwardly or
discharged through the thermal valve 95 which is operably connected
to the saturable core reactor 96 providing alternating current to
the downstream controlled heat exchanger D.
Circuit breaker control devices 98 provide means for interrupting
power to electrical power inputs and such circuit breaker devices
are connected for actuation by the safety control valve 82.
FIG. 4 of the drawing illustrates a portion of a coil tube section
of the pre-heater P or the reaction heat exchanger D showing in
section the chemically milled internal configuration of such
tubular device. In this arrangement the tube is provided with a
relatively large internal diameter thin wall portion designated
generally 100 which is positioned intermediate adjacent relatively
thick wall and small internal diameter sections 101 which, when
included as an electric resistance heater, provide different
temperatures for heating the fluid in such tubular devices. It will
be appreciated that the thinner wall sections will be heated more
than the thicker wall sections. Another example shown in FIG. 6 of
the drawings has a straight section of tube provided with a
substantially uniform internal diameter opening or passage 104 with
relieved or reduced thickness external wall sections 106 providing
hotter zones than the thicker wall portions 107 so that
longitudinally spaced "hot zones" may be provided in the tubular
devices D and P for heating the reactant chemicals passing
therethrough to various temperatures. It will be appreciated that
the various wall portions of such tubes may be made of a specific
thickness to provide the specific temperature desired in the tube,
and each of the various sections is made a particular length so as
to provide a flow time for subjecting the chemicals passing
therethrough to be exposed to the desired temperature for the
desired time.
Similarly, in FIGS. 5 and 7 there are shown various alternate
embodiments of chemically milled heating tubes having varying
internal diameters for providing varying heats for different
controlled periods of time for controlling the temperature of
fluids flowing therethrough. For instance, the tube shown in FIG. 7
includes reduced wall thickness sections 112 of a desired length
and alternate thickened wall sections 114 disposed therebetween.
Such wall sections each having a different heat or temperature
produced therein as a result of passing electrical current
therethrough to provide differing temperatures for each of the
sections to enable each section to heat the fluid passing
therethrough a desired amount. The length of the particular section
of tubing will determine the period of time fluid flowing through
the tube will be subjected to the temperature of any given section.
Also, the configuration shown in FIG. 7 provides turbulence in the
flow of fluid therethrough.
The other alternate embodiment, shown in FIG. 5 of the drawings,
provides a helical arrangement for inducing turbulence of a
particular pattern into the stream of fluid flowing therethrough
and also provides an alternate means for subjecting such fluid to
differing temperatures in the portions of the tube having differing
temperatures in the portions of the tube having different wall
thicknesses, such as the thickened wall sections 116 as compared to
the thinner wall sections 117. It will be further appreciated that
the wall thickness of any particular section may be determined in
accordance with the desired amount of temperature to be applied to
the fluid at that point in the flow pattern, and that the length of
such section may be determined according to the period of time the
fluid is to be subjected to that desired temperature. Thus, it
would be appreciated that the internally milled or externally
milled tubes illustrated in FIGS. 4, 5, 6, and 7 provide means for
controlling the temperature applied to fluid as it flows through a
section of tubular conduit.
Such milled tubular sections in a coiled heater or heat exchanger
are positioned to accomplish self-cycling action by virtue of the
unequal heating of the liquid or fluid in a coil tube wherein
convection currents are set up in either liquids or gases, the heat
being transmitted by molecules in the moving currents. The tubular
conduit may be reduced in wall thickness at long or short intervals
within the heater or heat exchanger to provide hot zones for a
desired resident period of time. The tubular conduit outer wall, or
inner wall for that matter, may be chemically etched so as to
provide operation thereof with a known temperature profile for a
given electrical energy input. With this arrangement, specific
heated zone sections may be provided that will accomplish precise
reaction zone heat conditions in such tubular heaters heat
exchangers.
In chemically milling the tubes, they may be formed in a coil
section, turned on a horizontal axis and partially filled with
etching acid. With the coils so filled, the tube is heated by
passing an electrical current therethrough or other means to
provide the proper etching temperature which will permit etching of
the acid filled portion of the tube to reduce its thickness for
providing higher resistivity and thereby produce a higher operating
temperature and self-cycling action of fluids being heated as they
pass therethrough.
FIGS. 2 and 3 illustrate alternate embodiments of the electrodes E
and F of the present invention wherein FIG. 2 shows flat plate
electrodes 120 and 121 which are separated by glass cloth 123 that
electrically insulates one from the other. In a preferred
embodiment of this invention these electrodes operate on
alternating current and permit an extremely long electrode arc with
an arc crater of greater effective area. Similarly, cylindrical
discs or truncated cones 125 such as shown in FIG. 3, may be used
to provide a uniform electrode erosion and air gap when heavy
sludge is in the arc crater. These electrodes can be arranged side
by side to provide a linear arc and can be rotated to provide
uniform wear. Also, these electrodes can withstand moderate
stresses at high temperatures which can produce crushing actions
desirable for waste materials and feed mechanisms. The
circumferences may be formed with teeth, grooves, and other shapes
which permit automatic feed. Using ATJ graphite, these electrodes
may be machined so that the arc may pass through porous waste
material while in rotation.
It will be appreciated that the self-cycling fluid heater of the
present invention may be applied to present processing systems or,
it may be made portable and operated as an oil skimmer picking up
floating oil and processing it into useful products while providing
a solution to pollution problems.
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the
size, shape, and materials as well as in the details of the
illustrated construction may be made without departing from the
spirit of the invention.
* * * * *