Title: Low operating pressure gas scrubber
Abstract: Provided herein is an apparatus for scrubbing either acidic or alkaline impurities from gas streams, wherein the gas streams to be scrubbed exist at a pressure which is only slightly higher than ambient pressure. An apparatus according to a preferred form of the invention exists substantially in the shape of a rectangular or cubic solid, having an inlet pipe which is directed to an inner chamber having a wall portion which functions as a manifold, including a plurality of gas conduction tubes in fluid contact with the inner chamber, and into which tubes the gas to be scrubbed enters. The gas to be scrubbed passes through holes in the walls of the gas conduction tubes and contacts a liquid absorbent substance present in the interior confines of the apparatus, which liquid is capable of reacting with one or more impurities in the gas stream, thus eliminating the impurities from the gas stream. The gas stream so treated emerges from the apparatus through a gas outlet provision.
Patent Number: 6,893,484 Issued on 05/17/2005 to Thomas
| Inventors:
|
Thomas; Paul E. (Odessa, TX)
|
| Assignee:
|
Desert Energy LTD (Odessa, TX)
|
| Appl. No.:
|
679208 |
| Filed:
|
October 6, 2003 |
| Current U.S. Class: |
95/226; 95/235; 96/353; 96/354; 261/123; 261/124; 422/231 |
| Intern'l Class: |
B01D 047/02 |
| Field of Search: |
261/1221,123,124,DIG. 9
96/351-354
95/226,235
422/231
210/221.2
|
References Cited [Referenced By]
U.S. Patent Documents
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| 941676 | Nov., 1909 | Green.
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| 1018996 | Feb., 1912 | Swett.
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| 2334232 | Nov., 1943 | Wells.
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| 3516647 | Jun., 1970 | Jaffe et al.
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| 3566583 | Mar., 1971 | Ashmore.
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| 3711072 | Jan., 1973 | Waldenville.
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| 3803812 | Apr., 1974 | Romero.
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| 4330510 | May., 1982 | Schauer et al.
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| 4350505 | Sep., 1982 | Mallory et al.
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| 4511379 | Apr., 1985 | Hauptmann.
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| 4564447 | Jan., 1986 | Tiedemann.
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| 4722799 | Feb., 1988 | Ashbrook et al.
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| 4933118 | Jun., 1990 | Meston.
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| 5064450 | Nov., 1991 | Lankton et al.
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| 5102583 | Apr., 1992 | Bannon.
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| 5376311 | Dec., 1994 | DeGuzman.
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| 5713971 | Feb., 1998 | Rohrbach et al.
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| 5730784 | Mar., 1998 | Smith et al.
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| 5851389 | Dec., 1998 | Brewster et al.
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| 6004381 | Dec., 1999 | Rohrbach et al.
| |
| 6506352 | Jan., 2003 | Lindfors et al.
| |
| 6547855 | Apr., 2003 | Schmidtke.
| |
| Foreign Patent Documents |
| 337804 | Jun., 1921 | DE.
| |
Primary Examiner: Chiesa; Richard L.
Attorney, Agent or Firm: Whewell; Christopher J.
Claims
1. A device useful for scrubbing contaminants from gaseous streams comprising:
a) an enclosure comprising a bottom portion, a rear wall portion, a front wall
portion, a left side wall portion and a right side wall portion, wherein said left
side wall portion and said right side wall portion each include a hole disposed
therethrough, one of said holes being a gas inlet and the remaining hole being
a gas outlet; and
b) a gas manifold portion comprising:
i) a substantially vertically disposed plate portion, said plate portion having
an upper end portion, a lower end portion, two side edge portions, and a plurality
of holes disposed through it along its lower end portion,
ii) a plurality of gas conduction tubes coinciding with the number of plurality
of holes disposed through said plate portion along its lower end portion, each
of said gas conduction tubes having a top surface portion, a first open end portion
and a second closed end portion, wherein said open end portion of each of said
gas conduction tubes are affixed over said holes disposed through said plate portion,
said gas conduction tubes each comprising a plurality of holes disposed along their
lengths,
iii) a substantially horizontally disposed plate top portion having two end portions
and two edge portions located at the upper end portion of the plate portion such
that the angle of intersection the plate top portion makes with the plate portion
is any angle between about 45 degrees and 135 degrees,
wherein said lower end portion of said plate portion is sealed along its length
to said bottom portion of said enclosure, and wherein each of said side edge portions
of said plate portion are sealed along each of their lengths to said front wall
portion and said rear wall portion of said enclosure, respectively, and wherein
each of said end portions of said plate top portion are sealed along their lengths
to said front wall portion and said rear wall portion of said enclosure and wherein
the edge portion of said plate top portion which does not intersect with said plate
portion is sealed along its length to said left side wall portion of said enclosure,
thus defining a sealed chamber defined by said plate portion, said plate top portion,
a portion of said front wall portion of said enclosure, a portion of said rear
wall portion of said enclosure, and a portion of said left side wall portion.
2. A device according to claim 1 wherein at least one of said right side wall,
left side wall, front wall or rear wall portions include two holes disposed through
it for charging and draining said device with a liquid absorbent substance.
3. A device according to claim 1 wherein said plurality of holes disposed through
said plate portion at its lower end portion comprises any number of holes between
about 2 and about 20.
4. A device according to claim 1 wherein said plurality of gas conduction tubes
is any number between about 2 and about 20.
5. A device according to claim 1 wherein the plurality of holes disposed along
the lengths of each of said gas conduction tubes comprises any number of holes
between about 8 holes and about 16 holes for every 2.5 centimeters of length of
said gas conduction tube.
6. A device according to claim 1 wherein each of the holes in said plurality
of holes disposed along the lengths of each of said gas conduction tubes have a
cross sectional area of any value in the range of between about 0.4 square centimeters
to about 1.2 square centimeters.
7. A device according to claim 1 wherein each of the holes in said plurality
of holes disposed along the lengths of each of said gas conduction tubes are round
and have a diameter of any value in the range of between about 1.5 millimeters
to about 4.5 millimeters.
8. A device according to claim 1 wherein the plurality of holes disposed along
the lengths of each of said gas conduction tubes are disposed so that there are
between about 8 holes and 16 holes for every 25 millimeters of length of said gas
conduction tubes.
9. A device according to claim 1 having a length dimension between about 20 centimeters
and about 200 centimeters, a width dimension between about 20 centimeters and about
200 centimeters, and a height dimension between about 1 centimeters and about 8 centimeters.
10. A device according to claim 1 further comprising a sheet of metal mesh disposed
across substantially all of said top surface portion of said gas conduction tubes.
11. A device according to claim 10 further comprising a sheet of expanded metal
disposed on the top of said sheet of metal mesh.
12. A device according to claim 11 further comprising a baffle means which comprises
a sheet of metal mesh disposed between two sheets of expanded metal, wherein said
baffle means is disposed above the top surface of the liquid absorbent substance
and wherein the top surface of the baffle means is below the lowest portion of
the opening of said gas outlet.
13. A device according to claim 1 further comprising a liquid absorbent substance
present within said enclosure, wherein the top surface of said liquid absorbent
substance is above the top surface of said gas conduction tubes, and further comprising
a baffle means which comprises a sheet of metal mesh disposed between two sheets
of expanded metal, wherein said baffle means is disposed above the top surface
of the liquid absorbent substance and wherein the top surface of the baffle means
is below the lowest portion of the opening of said gas outlet.
14. A device according to claim 13 wherein the angle of intersection of the plate
top portion and the plate portion is about 90 degrees.
15. A device according to claim 1 wherein the volume of said sealed chamber disposed
within said enclosure is between about 4000 cubic centimeters and 800,000 cubic
centimeters, excluding the volume contained in the gas conduction tubes.
16. A device according to claim 1 further comprising a liquid absorbent substance
present within said enclosure, wherein the top surface of said liquid absorbent
substance is above the top surface of said gas conduction tubes, but below the
lowest portion of the opening of said gas outlet.
17. A device according to claim 1 further comprising a liquid absorbent substance
present within said enclosure, wherein the liquid absorbent substance is disposed
so that its top surface is above the top surface of said gas conduction tubes,
and further comprising a baffle means which comprises a sheet of metal mesh disposed
between and in contact with each of two sheets of expanded metal, and wherein the
top surface of said liquid absorbent substance is below the bottom surface of said
baffle means.
18. A device according to claim 16 wherein said liquid absorbent substance is
selected from the group consisting of: acidic liquids and alkaline liquids.
19. A device according to claim 18 wherein said liquid absorbent substance is
alkaline and is selected from the group consisting of: triazine, alkanolamines,
aqueous caustic soda, monoethanolamine, diethanolamine, and triethanolamine.
20. A process for scrubbing a gaseous substance having an undesired impurity
present comprising the step of feeding said gaseous substance into said gas inlet
of a device according to claim 16, wherein said gaseous substance is at a pressure
of between about 0.1 psi and about 20 psi above the ambient pressure.
21. A process according to claim 20 wherein said impurity comprises hydrogen sulfide.
22. A process for scrubbing a gaseous substance having an undesired impurity
present comprising the step of feeding said gaseous substance into said gas inlet
of a device according to claim 17, wherein said gaseous substance is at a pressure
of between about 0.1 psi and about 20 psi above the ambient pressure.
23. A process according to claim 22 wherein said impurity comprises hydrogen sulfide.
24. A process for scrubbing a gaseous substance having an undesired impurity
present comprising the step of feeding said gaseous substance into said gas inlet
of a device according to claim 18, wherein said gaseous substance is at a pressure
of between about 0.1 psi and about 20 psi above the ambient pressure.
25. A process according to claim 24 wherein said impurity comprises hydrogen sulfide.
26. A process for scrubbing a gaseous substance having an undesired impurity
present comprising the step of feeding said gaseous substance into said gas inlet
of a device according to claim 19, wherein said gaseous substance is at a pressure
of between about 0.1 psi and about 20 psi above the ambient pressure.
27. A process according to claim 26 wherein said impurity comprises hydrogen sulfide.
Description
TECHNICAL FIELD
This invention relates to gas scrubbing equipment. More particularly it relates
to equipment suitable for scrubbing either acidic or alkaline impurities from gas
streams, wherein the gas stream to be scrubbed exists at a pressure which is only
slightly higher than ambient pressure.
BACKGROUND
The prior art is replete with various examples of devices and methods for the
removal or "scrubbing" of certain undesirable gaseous components from gas streams
in general. One area in which a large number of developments have been made is
in the scrubbing of gases produced during oil recovery and storage operations.
During such operations, poisonous hydrogen sulfide present presents a health hazard
to workmen in the area. To protect the workmen and the public-at-large, the permissible
conditions and levels for emissions of hydrogen sulfide are regulated by various
regulatory agencies. A few exemplary developments from the prior art follows, each
of which are herein incorporated by reference thereto.
U.S. Pat. No. 750,155 teaches a device having a suction producing means and
a water tank vertically discharging air through a nozzle below the surface of the
water in the tank. There is a sleeve loosely surrounding the nozzle and terminating
at its upper end just above the surface of the water, and a cap located a short
distance above the upper end of the sleeve.
U.S. Pat. No. 941,676 describes an apparatus for supplying atmospheres of various
humidities having: a) an air pump and a means for its operation; b) an air humidifying
tank containing water; c) an air tank; d) an exit pipe leading from each tank to
the pump; e) a pipe leading from the air tank to beneath the water level of the
humidifying tank; and f) a valve mechanism adapted to open communication directly
between the air tank and the pump, or indirectly through the humidifying tank.
U.S. Pat. No. 1,018,996 provides a tobacco smoke absorption apparatus having
a receptacle for containing liquid, a vertical pipe projecting through the top
of the receptacle and having its lower open end terminating adjacent to the bottom
of the receptacle, a combustion chamber having an open lower end, and a grating
above same, wherein the combustion chamber is mounted on the upper end of the vertical
pipe. It further includes a means for causing a downward draft from the combustion
chamber and up through the liquid containing receptacle and above it.
U.S. Pat. No. 4,330,510 sets forth a method of scrubbing noxious gas from a
gas stream which comprises: a) filling a closed upstanding container having a bottom,
a side wall, and a top cover with a gas washing liquid to a predetermined level,
the container having a baffle plate mounted substantially horizontally in the container
above the predetermined liquid level and being spaced from the side wall of the
container about at least substantially the entire periphery of the baffle plate
to permit cleansed gas to escape, the space between the baffle plate and the gas
washing liquid being substantially unobstructed, the baffle plate having a surface
facing the liquid in the lower portion of the container as gas is driven therethrough
and to act as an impact wall against which gas-containing bubbles impinge; b) pumping
a gas to be processed into at least one drive pipe having an inlet positioned outside
of the container and extending into the container with an outlet near the bottom
of the container appreciably below the predetermined liquid level to direct the
gas stream substantially vertically into the bottom of the container and to form
gas-containing bubbles in the gas washing liquid; c) discharging cleansed gas escaping
around the periphery of the baffle plate from the container through an outlet stack,
the outlet stack communicating with the interior of the container above the baffle
plate; and d) impacting the gas-containing bubbles against the baffle plate to
cause the gas-containing bubbles to recirculate through the liquid before passing
outwardly around the periphery of the baffle plate.
U.S. Pat. No. 4,350,505 discloses a device for treating gases containing nitrogen
for utilizing the nitrogen for reduction of oxygen content in well bore drilling
fluids and comprising: a) a housing means; b) a chamber provided in the housing
means and having a suitable filter material disposed therein to provide a filter
chamber; c) a chamber provided in the housing means below the filter chamber and
having a suitable liquid disposed therein to provide a liquid bath chamber d) a
stand-pipe means disposed in the housing means and providing communication between
the filter chamber and the liquid bath chamber; e) a level control means for controlling
the level of the liquid bath in the liquid bath chamber; f) a first discharge means
in communication with the liquid bath for discharge of the liquid bath; g) a second
discharge means in communication with the liquid bath chamber and disposed above
the upper level of the liquid bath; h) a means disposed in the liquid bath chamber
and disposed above the upper level of the liquid bath to provide a tortuous path
of travel between the liquid bath and the second discharge means; i) an inlet means
providing access to the interior of the filter chamber for admitting the nitrogen
containing gases thereto; and j) a means operably connected with the second discharge
means for creating a suction within the housing means for pulling the gases through
the filter chamber and liquid bath for removing unwanted debris from the gases
and discharging clean gases from the device, including spreader plate means disposed
in the filter chamber for dispersing the exhaust gases upon initial entry thereof
into the filter chamber.
U.S. Pat. No. 4,511,379 teaches a gas scrubber comprising a first chamber having:
a) inner and outer concentric substantially circular side walls each of constant
diameter; b) a first end wall extending between corresponding end edges of the
side walls; c) a helical second end wall extending between corresponding end edges
of the side walls and once therearound to adjacent the first end wall; d) a gas
inlet in the outer wall adjacent the position of maximum height thereof, the gas
inlet being positioned so as to direct gas passing therethrough tangentially between
the side walls; e) a plurality of fluid nozzles disposed on the inner wall so as
to spray liquid toward the outer wall; f) gas outlets extending substantially around
a side wall and dimensioned so that the velocity of the gas flowing between the
walls is substantially constant; and g) liquid outlet means to allow liquid to
leave the gas scrubber.
U.S. Pat. No. 4,722,799 describes an apparatus for continuously desulphurizing
natural gas and regenerating a reaction solution comprising: a) a contacting means
comprised of a tower and solution removal means, the contacting means for contacting
natural gas with the reaction solution to substantially oxidize sulphurous compounds
in the natural gas; b) a treating means comprised of a collector tank and a recycling
means, the recycling means operably connected to the contacting means and the collector
tank, the treating means for continuously regenerating the reaction solution, the
recycling means for circulating the reaction solution through the contacting means
and the treating means; c) a degassing means operably connected to the contacting
means and the treating means, the degassing means for removing entrained gases
from the reaction solution, wherein the degassing means is comprised of a colloid
mill and wherein the recycling means reduces sulphurous compounds in the solution
and causes sulphur to precipitate from the solution, the sulphur being removed
by a removal mechanism.
U.S. Pat. No. 4,933,118 provides a portable gas scrubbing apparatus comprising:
a) oblong casing means for containing a treatment fluid; b) inlet duct means in
one end of the casing means for introducing gas into the bottom of the one end
of the casing means; c) a first inclined baffle means extending between the sides
of the casing means from the one end of the casing means to proximate the other
end of the casing means; d) a second inclined baffle means above the first inclined
baffle means extending between the sides of the casing means from the other end
of the casing means to proximate the one end of the casing means, whereby, when
gas is introduced into the casing means to the treatment fluid and the baffle means,
the baffles define a circuitous path for gas introduced through the inlet means
into the treatment fluid beneath the first baffle means at the one end of the casing
means to the top surface of the fluid, thereby ensuring good contact between the
gas and the treatment fluid; and outlet duct means in the top of the casing means
for discharging treated gas from the casing means. The inlet duct means extends
into the casing beneath the first baffle means proximate the one end of the casing
means for introducing the gas beneath the first baffle means and horizontal tube
means connected to the inlet duct means beneath the first baffle means for distributing
the gas beneath the first baffle means.
U.S. Pat. No. 5,064,450 sets forth a gas absorber for removing at least one
gaseous component from a flowing gas stream by contacting the gas stream with a
lean liquid stream to absorb at least a portion of the gaseous component to produce
a rich liquid stream comprising the gaseous component and a flowing gas stream
having a reduced concentration of the gaseous component which absorber comprises:
a) a double wall forming an annulus having a means for restricting fluid flow into
the bottom of the gas absorber from the bottom of the annulus and a means for passing
fluid out of an upper section of the annulus into the gas absorber; b) an inlet
for the lean liquid stream having a locus in the upper end of the gas absorber;
c) an inlet for the flowing gas stream; d) an outlet for the rich liquid stream
having a locus in the lower end of the gas absorber; e) an outlet for the flowing
gas stream having a reduced concentration of the gaseous component; and f) at least
one inlet communicating with the lower end of the annulus which inlet is used to
introduce a lean liquid stream at least a portion of which flows upwardly through
the annulus and overflows from the top of the annulus and thereby protecting at
least a portion of the outer wall from contact with the flowing gas stream.
U.S. Pat. No. 5,102,583 discloses an apparatus for contacting a gas and a liquid
comprising: a) a substantially vertical column containing a plurality of substantially
horizontal contacting trays is which contacting tray is provided with passages
for gas and liquid and wherein at least one of the contacting trays is a control
tray; b) a liquid inlet provided in the upper section of the column; c) a gas outlet
located above the uppermost contacting tray; d) a gas inlet provided in the lower
section of the column; e) a liquid outlet below the lowermost contacting tray;
f) a means for controlling the flow of liquid from the control tray; and g) a differential
pressure controller responsive to means sensing the density of the mixture of gas
and liquid at least one contacting tray above the control tray which controller
communicates with the means for controlling the flow of liquid from the control
tray and wherein the differential pressure controller is activated by the pressure
difference between the space above the uppermost contacting tray and the space
below the control tray.
U.S. Pat. No. 5,376,311 teaches an apparatus for mixing gas and liquid comprising:
a) a generally rectangular concrete base; b) a vertically extending cylindrical
housing mounted on the concrete base and having a hollow interior, and open top
end portion and a bottom portion embedded on the concrete base, the bottom portion
being provided with horizontal reinforcing bars passing through the walls of the
cylindrical housing to anchor the housing with the concrete base, the cylindrical
housing being provided with a plurality of apertures disposed at the lower section
thereof proximate the concrete base; c) gas diffuser means concentrically held
inside the cylindrical housing; the gas diffuser means being defined by an elongated
porous tubular member provided with a cap fitted at the top end portion thereof
and an elbow fitting detachably secured at the bottom end portion thereof; d) an
inlet means consisting of a main pipe having opposite first and second ends, the
first end being fitted on the elbow fitting and the second end being connected
to a main air supply; and e) a holder means snugly fitted and screwably secured
inside the cylindrical housing, the holder means being adapted to hold the porous
tubular member in a vertical position as gas from the main supply is distributed therein.
U.S. Pat. No. 5,713,971 describes a cabin air filtration system for removing
gas phase contaminants comprising: a) a cavity; b) an air flow path through the
cavity; c) a liquid inlet into the cavity; d) a liquid outlet from the cavity;
e) a fibrous wicking material having a plurality of elongated strands which are
aligned to define a mesh within the cavity, the strands each having a hollow internal
region extending longitudinally along the strand connected to an outer surface
through at least one slot extending longitudinally along the strand, the hollow
internal region transferring liquid from the inlet to the outlet along a path transverse
to the air flow path; f) a means for supplying a gas absorbing liquid to the inlet;
g) a means for conveying the gas absorbing liquid and any absorbed gases therein
from the liquid outlet; and h) a means for circulating air from a cabin, through
the mesh along the air flow path, the cavity and back into the cabin, the gas phase
contaminants being communicated to the gas absorbing liquid through the slot in
the fiber wicking material whereby the gas phase contaminants are absorbed by the
gas absorbing liquid retained in the hollow region without essentially affecting
the air flow through the mesh.
U.S. Pat. No. 5,730,784 provides a process for the removal of hydrogen sulfide
from a gas stream containing hydrogen sulfide, which comprises: a) oxidizing a
portion of the hydrogen sulfide therein to form sulfur dioxide therefrom and to
produce an oxidized gas stream containing sulfur dioxide and a stoichiometric excess
of hydrogen sulfide; b) reacting substantially all the sulfur dioxide in the oxidized
gas stream with hydrogen sulfide remaining in the oxidized gas stream in a first
liquid phase to form sulfurous material therefrom contained in the first liquid
phase and to produce a further gas stream having a decreased and residual hydrogen
sulfide content; c) oxidizing substantially all hydrogen sulfide remaining in the
further gas stream in a second liquid phase to form a sulfurous material therefrom
contained in the second liquid phase and to produce a gas stream substantially
free from gaseous sulfur compounds, and d) venting the gas stream substantially
free from gaseous sulfur compounds.
U.S. Pat. No. 5,851,389 sets forth a device arranged to be longitudinally inserted
and removed from a conduit, and arranged to be positioned at a desired location
along the conduit to remove a contaminant from a fluid flowing through the conduit,
comprising a container having an axis, the container having: a) a first wall generated
about the axis, the first wall being permeable to the fluid stream; b) a second
wall generated about the axis, the second wall being spaced from the first wall
and being permeable to the fluid stream; c) the first wall defining a first volume;
d) the first and second walls defining a second volume therebetween; e) a first
member sealing the first and second volumes at one end of the container; f) a second
member sealing the second volume at the other end of the container, g) the second
volume occupied by filter material; and h) a expandable barrier impervious to the
fluid stream positioned adjacent the other end and selectively forming a seal between
the second wall and the wall of the conduit. The device may be longitudinally inserted
into a conduit and moved to a desired position therealong, and the barrier may
be selectively expanded to seal the space between the second wall and the conduit
wall, so that the fluid stream flowing through the conduit will be sequentially
directed into the first volume, through the first wall, into the second volume
where the filter material removes the contaminant from the fluid, and through the
second wall.
U.S. Pat. No. 6,004,381 discloses an apparatus for removing gas phase molecules
from a fluid stream comprising: a) a plurality of elongated fibers each having
a longitudinally extending hollow internal cavity including an opening extending
longitudinally along the fiber from the internal cavity to the outer fiber surface;
b) a liquid which can absorb the gas phase molecules disposed within the internal
cavities of the plurality of elongated fibers; c) a flow path for the fluid stream,
containing the gas phase molecules to be removed, directed over a portion of the
plurality of elongated fibers whereby the gas phase molecules to be removed are
absorbed by the liquid; and d) a means for directing the fluid stream along the
flow path.
U.S. Pat. No. 6,506,351 discloses a process for removing nitrogen oxides from
a gas stream comprising: a) feeding the gas stream to a nitrogen oxides adsorber
selected from the group consisting of a multi-fixed bed adsorber and a rotary wheel
adsorber containing a metal oxide based chemisorbent or an adsorbent selected from
the group consisting of Y zeolites, gamma alumina, treated gamma alumina, and supported
MgO, whereby the nitrogen oxides are adsorbed in the adsorber; and b) feeding an
ozone and oxygen containing gas stream to the adsorber, whereby the ozone reacts
with the nitrogen oxides to form N
2O
5.
The prior art includes many more examples of developments directed to similar
subject matter. However, none of the prior art devices provide a relatively portable
device which is capable of scrubbing gases like hydrogen sulfide from the headspaces
of storage tanks or other locations or sources at which the pressure of the gas
to be scrubbed exists at a pressure which is only slightly elevated over atmospheric
pressure. The present invention provides such apparatus.
SUMMARY OF THE INVENTION
The present invention provides a device useful for scrubbing contaminants from
gaseous streams comprising:
- a) an enclosure comprising a bottom portion, a rear wall portion, a
front wall portion, a left side wall portion and a right side wall portion, wherein
the left side wall portion and the right side wall portion each include a hole
disposed therethrough, one of said holes being a gas inlet and the remaining hole
being a gas outlet; and
- b) a gas manifold portion comprising:
- i) a substantially vertically disposed plate portion, the plate
portion having an upper end portion, a lower end portion, two side edge portions,
and a plurality of holes disposed through it along its lower end portion,
- ii) a plurality of gas conduction tubes coinciding with the number
of plurality of holes disposed through the plate portion along its lower end portion,
each of the gas conduction tubes having a first open end portion and a second closed
end portion, wherein the open end portion of each of the gas conduction tubes are
affixed over the holes disposed through the plate portion, the gas conduction tubes
each comprising a plurality of holes disposed along their lengths,
- iii) a substantially horizontally disposed plate top portion having
two end portions and two edge portions located at the upper end portion of the
plate portion such that the angle of intersection the plate top portion makes with
the plate portion is any angle between about 45 degrees and 135 degrees,
wherein the lower end portion of the plate portion is sealed along its length
to the bottom portion of the enclosure, and wherein each of the side edge portions
of the plate portion are sealed along each of their lengths to the front wall portion
and the rear wall portion of the enclosure, respectively, and wherein each of the
end portions of the plate top portion are sealed along their lengths to the front
wall portion and the rear wall portion of the enclosure and wherein the edge portion
of the plate top portion which does not intersect with the plate portion is sealed
along its length to the left side wall portion of the enclosure, thus defining
a sealed chamber defined by the plate portion, the plate top portion, a portion
of the front wall portion of the enclosure, a portion of the rear wall portion
of the enclosure, and a portion of the left side wall portion of the enclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
In the annexed drawings:
FIG. 1 shows a perspective view of a gas scrubbing apparatus according to the invention;
FIG. 2 shows a perspective view of a gas scrubbing apparatus according to the invention;
FIG. 3 shows a side view of a gas scrubbing apparatus according to the invention;
FIG. 4A shows a perspective view of a gas manifold useful in providing a gas
scrubbing apparatus according to the invention;
FIG. 4B shows an overhead perspective view of a gas manifold useful in providing
a gas scrubbing apparatus according to the invention;
FIG. 4C shows a side perspective view of a gas manifold useful in providing
a gas scrubbing apparatus according to the invention;
FIG. 5A shows a perspective view of a unshaped piece of sheet steel stock useful
in providing a gas scrubbing apparatus according to one method of manufacturing
a device according to the invention;
FIG. 5B shows an end view of a unshaped piece of sheet steel stock useful in
providing a gas scrubbing apparatus according to one method of manufacturing a
device according to the invention; and
FIG. 6 shows a cross section view of an assembled apparatus according to a preferred
form of the invention.
DETAILED DESCRIPTION
Referring to the drawings and initially to FIG. 1 there is shown a perspective
view of a gas scrubbing apparatus
10 according to the invention existing
substantially in the form of a rectangular solid and having a front wall portion
3, top portion
9, left side wall portion
11, and gas inlet
hole
5.
FIG. 2 shows a perspective view of a gas scrubbing apparatus
10 according
to the invention having front wall portion
3, top portion
9, right
side wall portion
13, gas outlet hole
7, liquid inlet hole
19,
and liquid drain hole
21.
In FIG. 3 is shown a side view of a gas scrubbing apparatus
10 according
to the invention showing the respective locations of the gas inlet hole
5,
gas outlet hole
7, liquid inlet hole
19, liquid drain hole
21,
and front wall portion
3.
In FIG. 4A there is shown a perspective view of a gas manifold
69 useful
in providing a gas scrubbing apparatus according to the invention, wherein the
gas manifold comprises a vertically-disposed plate portion
23 having an
upper end portion
80, a lower end portion
82, and two side edge portions
84 and
86, wherein there is a plate top portion
25 disposed
at the upper end portion of the plate portion
23 such that the plate top
portion
25 makes an angle of any value between about 45 degrees and 135
degrees at the point of its intersection with the plate portion
23; preferably
this angle is about 90 degrees. The manifold
69 also includes a plurality
of hollow gas conduction tubes
41, each of which have one open end and one
closed end, wherein the open end portion of the gas conduction tubes are attached
to the lower portion of the plate
23, over holes
47 disposed through
the plate
23 just above its lower portion. According to one preferred form
of the invention, each of the gas conduction tubes
41 are themselves provided
a plurality of holes
43 disposed on both their sides, along their entire
length. The conduction tubes
41 are preferably square in cross-section;
however the use of conduction tubes having other cross-section geometries are within
the scope of this invention, including round cross-sections, oval cross sections,
triangular cross sections, rectangular cross sections, rhombohedral cross sections,
trapezoidal cross sections, pentagonal cross sections, hexagonal cross sections,
etc. In all cases, including those where cross sectional geometries other than
square or rectangular are employed, the holes
43 are disposed so that their
axes are disposed at about a right angle with respect to the length dimension of
the gas conduction tubes
41. The plate top portion
25 includes two
end portions
88 and
90, and two edge portions
92 and
94.
The gas conduction tubes
41 are preferably affixed to the plate portion
23 by welding, as both the plate portion
23 and gas conduction tubes
41 comprise iron or steel in a preferred form of the invention. This is
accomplished by first providing the plate portion
23 to have a plurality
of holes
47 disposed at its lower portion which conform substantially to
the cross section of the gas conduction tubes
41, but are slightly smaller
in cross sectional area than the cross sectional area defined by the outer perimeter
of the cross section of the gas conduction tube at its intersection with the plate
portion
23, so as to enable a sound seal, ensuring that all of the open
space defined by each of the holes
47 is within the confines of the cross
section of the gas conduction tubes
43 at their open ends. The open end
of each of the gas conduction tubes
43 are placed over each hole
47
in the plate portion
23, and welded in position.
The plate top portion
25 is preferably attached to the plate portion
23
by welding in one form of the invention. According to an alternate form of the
invention, the plate top portion
25 is of singular construction as the plate
portion
23, i.e., it is the same piece, and the angle between 45 and 135
degrees at the intersection of the plate top portion
25 and plate portion
23 has been imparted by the bending of a single sheet of plate steel using
a brake and shear or other metal bending device, as such machines for bending steel
are known in the art. Materials of construction other than steel are contemplated
for providing the gas manifold
69 useful in providing an apparatus
10
according to the present invention, including other metals such as stainless steel,
aluminum, zinc, titanium, copper, brass, and other alloys. Additionally, the invention
comprises the use of composite materials, such as fiberglass, graphite-reinforced
composites, etc., as well as polymer sheets such as PVC, CPVC, polypropylene homopolymers,
copolymers of propylene and ethylene, polyethylene, ethylene-vinyl acetate copolymers,
and other organic polymers known in the art as possible materials of construction
of all elements of the invention.
FIG. 4B shows an overhead view of a gas manifold
69 useful in providing
a gas scrubbing apparatus
10 according to the invention, with its gas conduction
tubes
41 affixed to the plate portion
23. Also shown in this figure
is the plate top portion
25, and the locations of the plurality of holes
43 disposed about both of the side walls of each of the gas conduction tubes
41 in this embodiment in which the gas conduction tubes are of a square
cross section. Also shown in this FIG. 4B is the width dimension W
1
of the gas manifold
69 at its widest point, and its length dimension L
1.
FIG. 4C shows a side perspective view of a gas manifold
69 useful in
providing a gas scrubbing apparatus
10 according to the invention, having
plate portion
23, plate top portion
25, and gas conduction tubes
41. The location of the holes
43 is also shown disposed on the side
wall portions of the gas conduction tubes.
FIG. 5A shows a perspective view of a u-shaped piece of sheet steel stock
20
useful in providing a gas scrubbing apparatus
10 according to the invention,
the end view of which is shown in FIG.
5B. Such a u-shaped piece of steel
stock
20 is but one convenient means by which an apparatus according to
the invention may be provided. When this means for manufacture is chosen, one of
the walls serves as the front wall portion
3 of the apparatus, and one of
the walls serves as the rear wall portion
17, and the bottom portion
15
of the u-shaped steel stock
20 serves as the bottom portion
15 of
an apparatus
10 according to the invention. In its employment, the u-shaped
piece of steel stock
20 has a width dimension W
2, which is only
slightly wider than the width dimension W
1 of the gas manifold
69,
and a length dimension L
2, which is only slightly wider than the length
dimension L
1 of the gas manifold
69. Such provisions enable the
gas manifold
69 to be placed within the confines of the walls comprising
the front wall portion
3 and rear wall portion
17 so that the end
portions of the gas manifold
69 are substantially aligned with the ends
of the u-shaped steel stock
20. Subsequent to such placement, steel stock
having the dimensions of the left side wall portion
11 and right side wall
portion
13 are welded in place at the open end portions of the u-shaped
steel stock
20, and a suitably shaped top portion
9 is welded in
place on the top of the assembly, to provide an apparatus as shown in FIGS. 1,
2 and
3. The left side wall portion
11 is equipped with a
hole disposed through it to which a piece of pipe is attached to provide the gas
inlet
5, which serves as a convenient means for attaching a conduit which
supplies a gas needing to be scrubbed of impurities to the apparatus
10
for treatment. The right side wall portion
13 is equipped with a hole disposed
through it to which a piece of pipe is attached to provide the gas outlet
7,
which serves as a convenient means for attaching a conduit to convey the gas which
has been scrubbed of impurities to any desired location for venting to the atmosphere
or for further treatment, if desired or necessary. The right side wall portion
is also provided with two holes disposed through it which serve as locations for
filling and draining the apparatus of a liquid absorbent substance, such as an
alkaline liquid for cases where the apparatus
10 is to be used in scrubbing
acidic impurities from gas streams. The locations of these holes are at the specified
liquid inlet
19 and liquid drain
21, as previously described, and
preferably conveniently comprise a protruding circular boss having a threaded interior
wall that is adapted to receive a pipe plug for sealingly containing the liquid
absorbent substance within the interior confines of the apparatus welded over each
of the holes, similar to the drain on the crankcase of a combustion engine and
identical in function thereto.
According to an alternative means for manufacturing an apparatus according
to the invention, a hollow box shaped substantially in the form of a rectangular
solid comprising a bottom portion and four side wall portions is employed, whose
interior dimensions coincide with the length, width and height dimensions of the
gas manifold
69. The gas manifold
69 is dropped into such box and
welded in place as previously stated, to define the chamber
29 (FIG. 6)
and a top portion is subsequently welded in place in the location of the top portion
to comprise a sealed box having the gas manifold
69 tightly housed therein.
The gas inlet
5, gas outlet
7, liquid inlet
19, and liquid
drain
21 are provided as previously described.
FIG. 6 shows a cross section view of an assembled apparatus according to a preferred
form of the invention. In this figure, the purpose of the plate top portion
25
is evident. Prior to the affixing the top portion
9 to the apparatus, the
line of intersection between where the edge portion
92 (FIG. 4A) of the
plate top portion
25 contacts the left side wall portion
11 is sealed
along its length, for example, with a weld bead. Also, the points at which the
side edge portions
84 and
86 (FIG. 4A) of the plate portion
23
and the end portions
88 and
90 (FIG. 4A) of the plate top portion
25 contact the front wall portion
3 and rear wall portion
17
are all sealed along the length of these junctions as well, such as with a weld
bead. Such provision thus defines a sealed chamber
29, defined by the plate
portion
23, plate top portion
25, portions of each of the left side
wall portion
11 and portions of the front wall portion
3 and the
rear wall portion
17, into which chamber
29 all gas inputted to the
apparatus
10, represented by arrows in this FIG. 6, must enter. This chamber
29 is thus precluded from being in direct fluid contact with the headspace
77 in the remainder of the inner confines of the apparatus
10, particularly
when the liquid absorbent substance
27 is disposed in the device in its
normal use, at a level as shown. Preferably, the volume of the sealed chamber
29
disposed within the enclosure is between about 4000 cubic centimeters and 800,000
cubic centimeters, excluding the volume contained in the gas conduction tubes.
During operation of a gas scrubbing apparatus
10 according to the invention,
the gas to be scrubbed enters the gas inlet
5 at a pressure greater than
atmospheric by an amount in the range of between about 0.1 psi and about 20 psi
above atmospheric pressure, and travels down through chamber
29 in the direction
of the arrows until it encounters the plurality of holes
47 in the gas manifold
69. The gas to be scrubbed enters the gas conduction tubes
41 through
the holes
47 and exits the holes
43 which are disposed through the
walls of the gas conduction tubes, and contacts the liquid absorbent substance
27, with which acidic components present in the gas to be scrubbed chemically
react in the case where the liquid absorbent substance
27 is alkaline, to
form a neutralization product, such as a salt or adduct, by reaction with an alkaline
substance in the liquid absorbent substance. Alternatively, the gas to be scrubbed
may comprise an undesirable alkaline component, such as a volatile amine compound,
and the liquid absorbent substance may comprise an acidic substance. The gas, having
been relieved of its undesirable constituent(s) then passes into the headspace
77 and is directed outside of the apparatus
10 via the gas outlet
7 for further treatment, analysis, or venting to the atmosphere.
According to a preferred form of the invention, there is a layer of metal
mesh
39 which rests on the top surface of the gas conduction tubes
41,
which metal mesh may be any metallic mesh which does not restrict the flow of gas,
whose function is to aid in distribution of gas into the liquid phase. According
to one preferred form of the invention, the metal mesh is 4-ply material wherein
each layer has holes ½ centimeter by 1 centimeter. However other metal meshes
may be used, including meshes comprising carbon steel, Teflon® polymers, stainless
steel and various plastics having a mesh size between about ½ centimeter and
1 centimeter or any metallic element or alloy which is not attacked by the liquid
absorbent substance. There is also provided a sheet of expanded metal
35
which rests on top of the metal mesh
39 for the purpose of supporting the
metal mesh. The sheets of metal mesh
39 and expanded metal
35 are
both submerged beneath the surface of the liquid absorbent substance
27.
The expanded metal may comprise any expanded metal having openings in the range
of between ½ and 1.5 square inches in area which is comprised of iron, steel,
titanium, Teflon® polymers, other plastics (PE, PP, PVC, etc.) or any metallic
element or alloy which is not attacked by the liquid absorbent substance.
There is also a "sandwich" comprising a sheet of expanded metal
33 and
a sheet of expanded metal
31 having a sheet of metallic mesh
37 disposed
therebetween. The materials from which these expanded metal sheets and metal mesh
may be comprised are the same as mentioned above. This sandwich serves as a baffle,
for cases when sudden increases in line pressure of the gas to be scrubbed occur,
to prevent the liquid absorbent substance
27 from being forced out of the
gas outlet
7 in liquid form. This baffle means is held in place above the
top surface of the liquid absorbent substance
27 (and preferably substantially
parallel to the surface of the liquid absorbent substance
27), by conventional
means which may comprise an angle bracket disposed at each of the four corners
of the "sandwich" which comprises the baffle means. The top surface of the baffle
means
96 is preferably below the lowest portion of the opening of the gas
outlet
7. Also shown in FIG. 6 are the respective locations of the liquid
inlet
19 and the liquid drain.
As mentioned, an apparatus according to the invention operates to scrub undesirable
substances from gas streams by causing contact with the gas to be scrubbed and
a liquid absorbent substance
27. The liquid absorbent substance
27
may be any substance which is capable of undergoing a chemical reaction with an
undesirable chemical species present in the gas to be scrubbed. Thus, the present
invention contemplates the use of alkaline substances as the liquid absorbent substance,
for cases when it is desired to remove acidic components from the gas to be scrubbed.
Likewise, the present invention contemplates the use of acidic substances as the
liquid absorbent substance, for cases when it is desired to remove alkaline or
basic components from the gas to be scrubbed. In either case, both aqueous and
non-aqueous liquid absorbent substances may be used, as such are known in the chemical arts.
One use for which the present invention is particularly suited is for removing
hydrogen sulfide gas from gaseous hydrocarbons. In such employment, the preferred
liquid absorbent substance may be any substance used in the prior art for scrubbing
hydrogen sulfide from gaseous hydrocarbons, including amino compounds. Preferred
materials useful as the liquid absorbent substance in instances where hydrogen
sulfide is to be scrubbed include triazine; caustic soda solutions; zinc oxide
solutions; and alkanolamines, including without limitation: triethanolamine, diethanolamine,
and monoethanolamine.
One unique aspect of an apparatus according to the invention
10 is its
ability to scrub hydrogen sulfide from gaseous streams which are present at a pressure
which is only slightly in excess of atmospheric pressure. This is accomplished
by having the height of the liquid absorbent substance present in an apparatus
10 according to the invention to be about 14 centimeters from the bottom
portion
15. Thus the depth of the liquid absorbent substance within an apparatus
according to the invention is preferably between about 10 centimeters and 18 centimeters.
An apparatus according to the invention may take on any length and any width
dimension.
The length of the apparatus may be any length between about 25 centimeters long
to 200 centimeters long. The width of the apparatus may be any width between about
20 centimeters wide to 250 centimeters wide.
Although the preferred embodiment shown in the various figures comprises
5 gas conduction tubes
41, the scope of the present invention is not so
limited to gas manifolds
69 having 5 gas conduction tube
