U.S. patent application number 12/165817 was filed with the patent office on 2008-10-30 for submerged gas evaporators and reactors.
This patent application is currently assigned to LIQUID SOLUTIONS LLC. Invention is credited to Bernard F. Duesel, John P. Gibbons, Michael J. Rutsch.
Application Number | 20080265446 12/165817 |
Document ID | / |
Family ID | 37102976 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080265446 |
Kind Code |
A1 |
Duesel; Bernard F. ; et
al. |
October 30, 2008 |
SUBMERGED GAS EVAPORATORS AND REACTORS
Abstract
A submerged gas processor in the form of an evaporator or a
submerged gas reactor includes a vessel, a gas delivery tube
partially disposed within the vessel to deliver a gas into the
vessel and a process fluid inlet that provides a process fluid to
the vessel at a rate sufficient to maintain a controlled constant
level of fluid within the vessel. A weir is disposed within the
vessel adjacent the gas delivery tube to form a first fluid
circulation path between a first weir end and a wall of the vessel
and a second fluid circulation path between a second weir end and
an upper end of the vessel. During operation, gas introduced
through the tube mixes with the process fluid and the combined gas
and fluid flow at a high rate with a high degree of turbulence
along the first and second circulation paths defined around the
weir, thereby promoting vigorous mixing and intimate contact
between the gas and the process fluid. This turbulent flow develops
a significant amount of interfacial surface area between the gas
and the process fluid resulting in a reduction of the required
residence time of the gas within the process fluid to achieve
thermal equilibrium and/or to drive chemical reactions to
completion, all of which leads to a more efficient and complete
evaporation, chemical reaction, or combined evaporation and
chemical reaction process.
Inventors: |
Duesel; Bernard F.; (Goshen,
NY) ; Gibbons; John P.; (Cornwall, NY) ;
Rutsch; Michael J.; (Tulsa, OK) |
Correspondence
Address: |
MARSHALL, GERSTEIN & BORUN LLP
233 S. WACKER DRIVE, SUITE 6300, SEARS TOWER
CHICAGO
IL
60606
US
|
Assignee: |
LIQUID SOLUTIONS LLC
Maryland Heights
MO
|
Family ID: |
37102976 |
Appl. No.: |
12/165817 |
Filed: |
July 1, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11186459 |
Jul 21, 2005 |
7416172 |
|
|
12165817 |
|
|
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|
Current U.S.
Class: |
261/136 ;
261/123; 261/152 |
Current CPC
Class: |
B01J 2219/00135
20130101; B01D 1/14 20130101; B01J 2219/00166 20130101; B01J
19/2405 20130101; B01F 15/00883 20130101; B01J 2219/00777 20130101;
B01F 3/04248 20130101; B01J 2219/00768 20130101 |
Class at
Publication: |
261/136 ;
261/123; 261/152 |
International
Class: |
B01F 3/04 20060101
B01F003/04 |
Claims
1-9. (canceled)
10. The submerged gas processor of claim 30, further including a
reinforcing plate attached to the vessel and attached to the
weir.
11. The submerged gas processor of claim 10, further including a
stabilizer ring attached to the reinforcing plate and disposed
between the gas tube and the weir.
12-15. (canceled)
16. The submerged gas processor of claim 30, further including a
jacket disposed adjacent to an outer wall of the vessel that may be
used for either heating or cooling the process liquid.
17. The submerged gas processor of claim 16, wherein the jacket
includes a fluid volume that enables heating or cooling fluid to
circulate adjacent the vessel.
18. The submerged gas processor of claim 16, wherein the jacket
includes an electrical heating element.
19-29. (canceled)
30. A submerged gas processor comprising: a vessel capable of
holding a fluid, wherein the fluid, when disposed in an at rest
condition within the vessel defines an at rest fluid level within
the vessel; a fluid inlet disposed within the vessel; a gas tube
extending into the vessel adapted to transport a gas into the
interior of the vessel, the gas tube including a gas exit port
disposed below the at rest fluid level; an exhaust port disposed in
the vessel adapted to transport gas from the interior of the
vessel; and a weir, having a first end and a second end, the weir
disposed adjacent the gas exit port within the vessel to create a
confined volume between the tube and the weir; wherein the weir
includes a first end and a second end and wherein at least a
substantial portion of the weir is disposed below the at rest fluid
level within the vessel so as to form a first circulation gap
between the first weir end and a first wall of the vessel and to
form a second circulation gap between the second weir end and a
second wall of the vessel.
31. (canceled)
32. The submerged gas processor of claim 30, wherein the second end
of the weir is disposed at or above the at rest fluid level of the
vessel.
33. (canceled)
34. The submerged gas processor of claim 30, further including a
baffle disposed within the vessel at or above the at rest fluid
level of the vessel.
35. The submerged gas processor of claim 30, further including a
baffle disposed within the vessel above the second end of the
weir.
36. (canceled)
37. (canceled)
38. The submerged gas processor of claim 30, further including a
heating device associated with the vessel.
39. The submerged gas processor of claim 30, further including a
cooling device associated with the vessel.
40. The submerged gas processor of claim 30, wherein the weir
comprises a tubular member disposed around the gas tube.
41. The submerged gas processor of claim 40, wherein the tubular
member is circular in cross section.
42. The submerged gas processor of claim 40, wherein the tubular
member is disposed co-axial to the gas tube.
43-59. (canceled)
60. A submerged gas processor comprising: a vessel; a fluid inlet
disposed within the vessel; a weir disposed within the vessel to
define a first volume and a second volume within the vessel; a gas
delivery tube extending into the vessel, the gas delivery tube
including a gas exit disposed in the first volume; a gas exhaust
port disposed in the vessel; and a biogas burner attached to the
gas delivery tube; wherein the weir includes a first weir end and a
second weir end and is disposed within the vessel to create a first
fluid circulation path adjacent the first weir end to allow fluid
to flow from the first volume to the second volume and to create a
second fluid circulation path adjacent the second weir end to allow
fluid to flow from the second volume to the first volume when gas
is introduced into the first volume from the gas exit.
61. The submerged gas processor of claim 60, the first weir end is
disposed above the gas exit and the second weir end is disposed
below the gas exit.
62. The submerged gas processor of claim 60, wherein the first
volume is smaller than the second volume.
63. The submerged gas processor of claim 60, wherein the second
fluid circulation path is formed between the second weir end and a
bottom wall of the vessel.
64. The submerged gas processor of claim 60, further including a
baffle disposed within the vessel above the first volume adjacent
the first weir end.
65. The submerged gas processor of claim 60, further including a
heating device disposed adjacent an outer wall of the vessel or
associated with the vessel.
66. The submerged gas processor of claim 60, further including a
cooling device disposed within or adjacent to the vessel.
67-69. (canceled)
70. The submerged gas processor of claim 60, wherein the weir
comprises a generally flat plate member.
71. The submerged gas processor of claim 70, wherein the generally
flat plate member extends across the vessel between opposite sides
of the vessel.
72. The submerged gas processor of claim 60, further including a
burner that operates on gaseous or liquid fuel attached to the gas
tube.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates generally to devices that mix
gases and liquids, and more specifically, to submerged gas
processors including submerged gas evaporators and submerged gas
reactors.
BACKGROUND
[0002] Submerged gas evaporators, submerged gas reactors and
combination submerged gas evaporator/reactor systems in which gas
is dispersed within the liquid phase, referred to generally herein
as submerged gas processors, are well known types of devices used
in many industries to perform evaporation and chemical reaction
processes with respect to various constituents. U.S. Pat. No.
5,342,482, discloses a common type of submerged combustion gas
evaporator, in which combustion gas is generated and delivered
though an inlet pipe to a dispersal unit submerged within the
liquid to be evaporated. The dispersal unit includes a number of
spaced-apart gas delivery pipes extending radially outward from the
inlet pipe, each of the gas delivery pipes having small holes
spaced apart at various locations on the surface of the gas
delivery pipe to disperse the combustion gas as small bubbles as
uniformly as practical across the cross-sectional area of the
liquid held within the processing vessel. According to current
understanding within the prior art, this design provides desirable
intimate contact between the liquid and the combustion gas over a
large interfacial surface area while also promoting thorough
agitation of the liquid within the processing vessel.
[0003] Because submerged gas processors do not employ heat
exchangers with solid heated surfaces, these devices provide a
significant advantage when compared to conventional evaporators or
chemical reactors when contact between a liquid stream and a gas
stream is desirable. In fact, submerged gas processors are
especially advantageous when the desired result is to highly
concentrate a liquid stream by means of evaporation.
[0004] However, many feed streams, prior to reaching a desired
concentration, produce solids in the form of precipitates that are
difficult to handle. These precipitates may include substances that
form deposits on the solid surfaces of heat exchangers used in
conventional evaporators, and substances that tend to form large
crystals or agglomerates that can block passages within processing
equipment, such as the gas exit holes in the system described in
U.S. Pat. No. 5,342,482. Generally speaking, feed streams that
cause deposits to form on surfaces and create blockages within
process equipment are called fouling fluids.
[0005] Additionally, common problems within conventional
evaporation and chemical reaction systems used for processing
fouling fluids include deterioration of the rate of heat transfer
over time due to the buildup of deposits on solid heat exchange
surfaces and equipment malfunctions related to blockages in
critical locations such as gas outlet pipes. These common problems
adversely affect the efficiency and costs of conventional processes
in that the potential for buildup of deposits and blockages
necessitate frequent cleaning cycles to avoid sudden failures
within the evaporation or reaction equipment.
[0006] Additionally, most evaporation and chemical reactor systems
that rely on intimate contact between gases and liquids are prone
to problems related to carryover of entrained liquid droplets that
form as the vapor phase disengages from the liquid phase. For this
reason, most evaporator and chemical reactor systems that require
intimate contact of gas with liquid include one or more devices to
minimize entrainment of liquid droplets and/or to capture entrained
liquid droplets while allowing for separation of the entrained
liquid droplets from the exhaust gas flowing out of the evaporation
zone. The need to mitigate carryover of entrained liquid droplets
may be related to one or more factors including conformance with
environmental regulations, conformance with health and safety
regulations and controlling losses of material that might have
significant value.
[0007] Unlike conventional evaporators and reactors where heat is
transferred to the material being processed through heat exchangers
with solid surfaces, heat and mass transfer within submerged gas
processors take place at the interface of a discontinuous gas phase
dispersed within a continuous liquid phase. Compared to the fixed
solid heat transfer surfaces employed in conventional evaporators
and reactors, fouling fluids cannot coat the heat transfer surface
within submerged gas processors as new surface area is constantly
being formed by a steady flow of gas which is dispersed within the
liquid phase and remains in contact with the liquid for a finite
period of time before disengaging. This finite period of time is
called the residence time of the gas within the evaporation, or
evaporation/reaction zone.
[0008] Submerged gas processors also tend to mitigate the formation
of large crystals because dispersing the gas beneath the liquid
surface promotes vigorous agitation within the evaporation or the
evaporation/reaction zone, which is a less desirable environment
for crystal growth than a more quiescent zone. Further, active
mixing within an evaporation or reaction vessel tends to maintain
precipitated solids in suspension and thereby mitigates blockages
that are related to settling and/or agglomeration of suspended
solids.
[0009] However, mitigation of crystal growth and settlement is
dependent on the degree of mixing achieved within a particular
submerged gas processor, and not all submerged gas processor
designs provide adequate mixing to prevent large crystal growth and
related blockages. Therefore, while the dynamic renewable heat
transfer surface area feature of submerged gas processors
eliminates the potential for fouling liquids to coat heat exchange
surfaces, conventional submerged gas processors are still subject
to potential blockages and carryover of entrained liquid within the
exhaust gas flowing away from the evaporation zone.
[0010] Direct contact between hot gas and liquid undergoing
processing within a submerged gas processor provides excellent heat
transfer efficiency. If the residence time of the gas within the
liquid is adequate for the gas and liquid temperatures to equalize,
a submerged gas processor operates at a high level of overall
energy efficiency. For example, when hot gas is dispersed in a
liquid that is at a lower temperature than the gas and the
residence time is adequate to allow the gas and liquid temperatures
to attain the adiabatic operating temperature for the system, all
of the available driving force of temperature differential will be
used to transfer thermal energy from the gas to the liquid. The
minimum residence time to attain equilibrium of gas and liquid
temperatures within the evaporation, reaction or combined
reaction/evaporation zone of a submerged gas processor is a
function of factors that include, but are not limited to, the
temperature differential between the hot gas and liquid, the
properties of the gas and liquid phase components, the properties
of the resultant gas-liquid mixture, the net heat absorbed or
released through any chemical reactions and the extent of
interfacial surface area generated as the hot gas is dispersed into
the liquid.
[0011] Given a fixed set of values for temperature differential,
properties of the gas and the liquid components, properties of the
gas-liquid mixture, heats of reaction and the extent of the
interfacial surface area, the residence time of the gas is a
function of factors that include the difference in specific gravity
between the gas and liquid or buoyancy factor, and other forces
that affect the vertical rate of rise of the gas through the liquid
phase including the viscosity and surface tension of the liquid.
Additionally, the flow pattern of the liquid including any mixing
action imparted to the liquid such as that created by the means
chosen to disperse the gas within the liquid affect the rate of gas
disengagement from the liquid.
[0012] Submerged gas processors may be built in various
configurations. One common type of submerged gas processor is the
submerged combustion gas evaporator that generally employs a
pressurized burner mounted to a gas inlet tube that serves as both
a combustion chamber and as a conduit to direct the combustion gas
to a dispersion system located beneath the surface of liquid held
within an evaporation vessel. The pressurized burner may be fired
by any combination of conventional liquid or gaseous fuels such as
natural gas, oil or propane, any combination of non-conventional
gaseous or liquid fuels such as biogas or residual oil, or any
combination of conventional and non-conventional fuels.
[0013] Other types of submerged gas processors include hot gas
evaporators where hot gas is either injected under pressure or
drawn by an induced pressure drop through a dispersion system
located beneath the surface of liquid held within an evaporation
vessel. While hot gas evaporators may utilize combustion gas such
as hot gas from the exhaust stacks of combustion processes, gases
other than combustion gases or mixtures of combustion gases and
other gases may be employed as desired to suit the needs of a
particular evaporation process. Thus, waste heat in the form of hot
gas produced in reciprocating engines, turbines, boilers or flare
stacks may be used within hot gas evaporators. In other forms, hot
gas evaporators may be configured to utilize specific gases or
mixtures of gases that are desirable for a particular process such
as air, carbon dioxide or nitrogen that are heated within heat
exchangers prior to being injected into or drawn through the liquid
contained within an evaporation vessel.
[0014] Regardless of the type of submerged gas processor or the
source of the gas used within a processor, in order for the process
to continuously perform effectively, reliably and efficiently, the
design of the submerged gas processor must include provisions for
efficient heat and mass transfer between gas and liquid phases,
control of entrained liquid droplets within the exhaust gas,
mitigating the formation of large crystals or agglomerates of
particles and maintaining the mixture of solids and liquids within
the submerged gas processing vessel in a homogeneous state to
prevent settling of suspended particles carried within the liquid
feed and/or precipitated solids.
SUMMARY OF THE DISCLOSURE
[0015] A simple and efficient submerged gas processor includes an
evaporation, reaction or combination evaporation/reaction vessel, a
tube partially disposed within the vessel which is adapted to
transport a gas into the interior of the vessel, a process fluid
inlet adapted to transport a process fluid into the vessel at a
rate that maintains the process fluid inside the vessel at a
predetermined level and an exhaust stack that allows spent gas to
flow away from the vessel. In addition, the submerged gas processor
includes a weir disposed within the reaction vessel. The weir may
at least partially surround the tube and may be submerged in the
process fluid to create a fluid circulation path around the weir
within the vessel. In one embodiment, the weir is open at both ends
and forms a lower circulation gap between a first one of the weir
ends and a bottom wall of the vessel and an upper circulation gap
between a second one of the weir ends and a normal process fluid
operating level.
[0016] During operation, gas introduced through the tube mixes with
the process fluid in a first confined volume formed by the weir,
and the fluid mixture of gas and liquid flows at high volume with a
high degree of turbulence along the circulation path defined around
the weir, thereby causing a high degree of mixing between the gas
and the process fluid and any suspended particles within the
process fluid. Shear forces within this two-phase or three-phase
turbulent flow that result from the high density liquid phase
overrunning the low density gas phase create extensive interfacial
surface area between the gas and the process fluid that favors
minimum residence time for mass and heat transfer between the
liquid and gas phases to come to equilibrium compared to
conventional gas dispersion techniques. Still further, vigorous
mixing created by the turbulent flow hinders the formation of large
crystals of precipitates within the process fluid and, because the
system does not use small holes or other ports to introduce the gas
into the process fluid, clogging and fouling associated with other
submerged gas processors are significantly reduced or entirely
eliminated. Still further, the predominantly horizontal flow
direction of the liquid and gas mixture over the top of the weir
and along the surface of the process fluid within the processing
vessel enables the gas phase to disengage from the process fluid
with minimal entrainment of liquid due to the significantly greater
momentum of the much higher density liquid that is directed
primarily horizontally compared to the low density gas with a
relatively weak but constant vertical momentum component due to
buoyancy.
[0017] In addition, a method of processing fluid using a submerged
gas processor includes providing a process fluid to a vessel of a
submerged gas processor at a rate sufficient to maintain the fluid
level at a predetermined level within the vessel, supplying a gas
to the vessel, and mixing the gas and process fluid within the
vessel by causing the gas and process fluid to flow around a weir
within the submerged gas processor to thereby transfer heat energy
and mass between the gas and liquid phases of a mixture and/or to
otherwise react constituents within the gas and liquid phases of a
mixture.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a cross-sectional view of a submerged gas
processor constructed in accordance with the teachings of the
disclosure.
[0019] FIG. 2 is a cross-sectional view of a second submerged gas
processor including a baffle.
[0020] FIG. 3 is a cross-sectional view of a third submerged gas
processor having a tubular shaped weir.
[0021] FIG. 4 is a top plan view of the submerged gas processor of
FIG. 3.
[0022] FIG. 5 is a cross-sectional view of a fourth submerged gas
processor connected to a source of waste heat.
[0023] FIG. 6 is a cross-sectional view of a submerged gas
processor having a heating blanket disposed around an exterior
portion thereof.
DETAILED DESCRIPTION
[0024] Referring to FIG. 1, a submerged gas processor 10, in the
form of a submerged combustion gas evaporator, includes a burner 20
and a hot gas supply tube or gas inlet tube 22 having sparge or gas
exit ports 24 at or near an end 26 thereof. The gas inlet tube 22
is disposed within an evaporator vessel 30 having a bottom wall 31
and a process fluid outlet port 32. A process fluid inlet port 34
is disposed in one side of the vessel 30 and enables a process
fluid 35 (and other liquids) to be provided into the interior of
the vessel 30. Additionally, a weir 40, which is illustrated in
FIG. 1 as a flat or solid plate member having a first or lower end
41 and a second or upper end 42, is disposed within the vessel 30
adjacent the gas inlet tube 22. The weir 40 defines and separates
two volumes 70 and 71 within the vessel 30. As illustrated in FIG.
1, a gas exit port 60 disposed in the top of the vessel 30 enables
gas to exit from the interior of the vessel 30.
[0025] In the submerged combustion gas evaporator of FIG. 1, the
burner 20, which may be a nozzle mix or pre-mix type of pressurized
burner, is supplied with fuel under pressure from a blower or pump
(not shown in FIG. 1) through a line 51 and is supplied with air
under pressure from a blower (not shown in FIG. 1) through a line
53. Moreover, the process fluid 35 may be supplied through the
fluid inlet 34 by a pump (not shown in FIG. 1) at a rate sufficient
to maintain a surface 80 of the process fluid 35 within the vessel
30 at a predetermined level, which may be set by a user. A level
sensor and control (not shown in FIG. 1) may be used to determine
and control the rate that the process fluid 35 is supplied through
the inlet port 34.
[0026] As illustrated in FIG. 1, the weir 40 is mounted within the
vessel 30 to form a lower circulation gap 36 between the first end
41 of the weir 40 and the bottom wall 31 of the vessel 30 and to
form an upper circulation gap 37 between the second end 42 of the
weir 40 and the surface 80 of the process fluid 35 (or the top wall
of the vessel 30). As will be understood, the upper end 42 of the
weir 40 is preferably set to be at or below the surface level 80 of
the process fluid 35 when the process fluid 35 is at rest (i.e.,
when no gas is being introduced into the vessel via the gas inlet
tube 22). In some situations, it may be possible to set the upper
end 42 of the weir 40 slightly above the at rest level of the
process fluid 80, as long as introduction of the gas via the gas
inlet tube 22 still causes liquid to flow over the upper end 42 of
the weir 40. In any event, as illustrated in FIG. 1, the weir 40
also defines and separates the confined volume or space 70 in which
the sparge ports 24 are located from the volume or space 71. If
desired, the weir 40 may be mounted to the vessel 30 via welding,
bolts or other fasteners attached to internal side walls of the
vessel 30.
[0027] During operation, a pressurized mixture of gas and air from
the lines 51 and 53 is ignited within the burner 20 and is forced
to flow under pressure into and through the gas inlet tube 22 where
combustion of the fuel is completed before the combusted fuel/air
mixture (hereinafter "combustion gas") reaches the sparge or exit
ports 24. The combustion gas exits the gas inlet tube 22 through
the sparge ports 24 into the confined volume 70 formed between the
weir 40 and the gas inlet tube 22, causing the combustion gas to be
dispersed into the continuous liquid phase of the process fluid
within the vessel 30. Generally speaking, gas exiting from the
sparge ports 24 mixes with the liquid phase of the process fluid
within the confined volume 70 and causes a high volume flow pattern
to develop around the weir 40. The velocity of the flow pattern and
hence the turbulence associated with the flow pattern is highest
within the confined volume 70 and at the locations where the liquid
flows through the upper gap 37 and the lower gap 36 of the weir 40.
The turbulence within the confined volume 70 significantly enhances
the dispersion of the gas into the process fluid which, in turn,
provides for efficient heat and mass transfer between the gas and
the process fluid. In particular, after exiting the sparge ports
24, the combustion gas is dispersed as a discontinuous phase into a
continuous liquid phase of the process fluid forming a gas/liquid
mixture within the confined volume 70. The mass per unit volume of
the gas/liquid mixture in the confined volume 70 is significantly
less than that of the continuous liquid phase of the process fluid
in the volume 71. Due to this large difference in mass per unit
volume of the liquid compared to the gas, typically on the order of
approximately 1000 to 1, a difference in static hydraulic pressure
is formed between the gas/liquid mixture in the confined volume 70
and the liquid phase in the volume 71 at all elevations. This
imbalance in static hydraulic pressure forces the process fluid to
flow from the higher pressure region, i.e., the volume 71, to the
lower pressure region, i.e., the confined volume 70, at a rate that
overcomes the impressed static hydraulic pressure imbalance and
creates flow upward through the confined volume 70.
[0028] Put another way, the dispersion of gas into the process
fluid 35 within the confined volume 70 at the sparge ports 24
develops a continuous flow pattern that draws process fluid 35
under the bottom edge 41 of the weir 40 through the lower
circulation gap 36, and causes the mixture of gas and process fluid
35 to move through the confined volume 70 and toward the surface 80
of the process fluid 35. Near the surface 80, the gas/liquid
mixture reaches a point of balance at which the imbalance of static
hydraulic pressure is eliminated. Generally speaking, this point is
at or near the upper circulation gap 37 formed between the second
end 42 of the weir 40 and the process fluid surface 80. At the
balance point, the force of gravity, which becomes the primary
outside force acting on the gas/fluid mixture, gradually reduces
the vertical momentum of the gas/liquid mixture to near zero. This
reduced vertical momentum, in turn, causes the gas/liquid mixture
to flow in a predominantly horizontal direction over the second end
42 of the weir 40 (through the circulation gap 37 defined at or
near the surface 80 of the process fluid 35) and into the liquid
phase of the process fluid 35 within the volume 71.
[0029] This flow pattern around the weir 40 affects the dispersion
of the combustion gas into the continuous liquid phase of the
process fluid 35 and, in particular, thoroughly agitates the
continuous liquid phase of the process fluid 35 within the vessel
30 while creating a substantially horizontal flow pattern of the
gas/liquid mixture at or near the surface 80 of the continuous
liquid phase of the process fluid 35. This horizontal flow pattern
significantly mitigates the potential for entrained liquid droplets
to be carried vertically upward along with the dispersed gas phase
as the dispersed gas phase rises through the liquid phase due to
buoyancy and finally disengages from the continuous liquid phase of
the process fluid at the surface 80 of the process fluid 35.
[0030] Also, the mixing action created by the induced flow of
liquid and liquid/gas mixtures within both the confined volume 70
and the volume 71 hinders the formation of large crystals of
precipitates, which generally requires a quiescent environment. By
selectively favoring the production of relatively small particles
of precipitates, the mixing action within vessel 30 helps to ensure
that suspended particles formed in the submerged gas evaporation
process may be maintained in suspension within the liquid phase
circulating around the weir 40, which effectively mitigates the
formation of blockages and fouling within the submerged gas
evaporator. Likewise, because relatively small particles that are
readily maintained in suspension are formed through precipitation,
the efficiency of the evaporator is improved over conventional
evaporation systems in terms of freedom from clogging and fouling
and the degree to which the feed liquid may be concentrated.
[0031] In addition, as the circulating liquid phase within volume
71 approaches the bottom wall 31 of the vessel 30, the liquid phase
is forced to flow in a predominantly horizontal direction and
through the lower gap 36 into the confined volume 70. This
predominantly horizontal flow pattern near the bottom wall 31 of
the vessel 30 creates a scouring action at and above the interior
surface of the bottom wall 31 which maintains particles of solids
including precipitates in suspension within the circulating liquid
while the submerged combustion gas evaporator is operating. The
scouring action at and near the bottom wall 31 of the vessel 30
also provides means to re-suspend settled particles of solids
whenever the submerged gas evaporator is re-started after having
been shutdown for a period of time sufficient to allow suspended
particles to settle on or near the bottom wall 31.
[0032] As is known, submerged gas evaporation is a process that
affects evaporation by dispersing a gas within a liquid or liquid
mixture, which may be a compound, a solution or slurry. Within a
submerged gas evaporator heat and mass transfer operations occur
simultaneously at the interface formed by the dynamic boundaries of
the discontinuous gas and continuous liquid phases. Thus, all
submerged gas evaporators include some method to disperse gas
within a continuous liquid phase. The system shown in FIG. 1
however integrates the functions of dispersing the gas into the
liquid phase, providing thorough agitation of the liquid phase, and
mitigating entrainment of liquid droplets with the gas phase as the
gas disengages from the liquid. Additionally, the turbulence and
mixing that occurs within the vessel 30 due to the flow pattern
created by dispersion of gas into liquid within the confined volume
70 reduces the formation of large crystals of precipitates and/or
large agglomerates of smaller particles within the vessel 30.
[0033] FIG. 2 illustrates a second embodiment of a submerged gas
processor 110, which is very similar to the submerged gas
evaporator 10 of FIG. 1 and in which elements shown in FIG. 2 are
assigned reference numbers being exactly 100 greater than the
corresponding elements of FIG. 1. Unlike the device of FIG. 1, the
submerged gas processor 110 includes a baffle or a shield 138
disposed within the vessel 130 at a location slightly above or
slightly below the fluid surface 180 and above the second end 142
of the weir 140. The baffle or shield 138 may be shaped and sized
to conform generally to the horizontal cross-sectional area of the
confined volume 170. Additionally, if desired, the baffle 138 may
be mounted to any of the gas inlet tube 122, the vessel 130 or the
weir 140. The baffle 138 augments the force of gravity near the
balance point by presenting a physical barrier that abruptly and
positively eliminates the vertical components of velocity and
hence, momentum, of the gas/liquid mixture, thereby assisting the
mixture to flow horizontally outward and over the weir 140 at the
upper circulation gap 137.
[0034] As will be understood, the weirs 40 and 140 of FIGS. 1 and 2
may be generally flat plates or may be curved plates that extend
across the interior of the vessel 30 between different, such as
opposite, sides of the vessel 30. Basically, the weirs 40 and 140
create a wall within the vessel defining and separating the volumes
70 and 71 (and 170 and 171). While the weirs 40 and 140 are
preferably solid in nature they may, in some cases, be perforated,
for instance, with slots or holes to modify the flow pattern within
the vessel 10 or 110, or to attain a particular desired mixing
result within the volume 71 or 171 while still providing a
substantial barrier between the volumes 70 and 71 or 170 and 171.
Additionally, while the weirs 40 and 140 preferably extend across
the vessels 30 and 130 between opposite walls of the vessels 30 and
130, they may be formed into any desired shape so long as a
substantial vertical barrier is formed to isolate one volume 70 (or
170) closest to the gas inlet tube 22 from the volume 71 (or 171)
on the opposite side of the weir 40, 140.
[0035] FIG. 3 illustrates a cross-sectional view of a further
submerged gas processor 210 having a weir 240 that extends around a
gas inlet tube 222. The submerged gas processor 210, which may be a
submerged gas evaporator, a submerged gas chemical reactor or a
combination submerged gas evaporator/chemical reactor, generally
speaking has evaporative capacity equivalent to approximately
10,000 gallons per day on the basis of evaporating water from
process liquid. A combustion device (not shown in FIG. 3) delivers
approximately 2,200 standard cubic feet per minute (scfm) of
combustion gas at 1,400.degree. F. or approximately 11,058 actual
cubic feet per minute (acfm) to the gas inlet tube 222. While the
dimensions of the submerged gas processor 210 are exemplary only,
the ratios between these dimensions may serve as a guide for those
skilled in the art to achieve a desirable balance between three
desirable process results including: 1) preventing the formation of
large crystals of precipitates and/or agglomerates of solid
particles while maintaining solid particles as a homogeneous
suspension within the process liquid by controlling the degree of
overall mixing within vessel 230; 2) enhancing the rates of heat
and mass transfer and any desirable chemical reactions by
controlling the turbulence and hence interfacial surface area
created between the gas and liquid phases within confined volume
270; and 3) mitigating the potential of entraining liquid droplets
in the gas as the gas stream disengages from the liquid phase at
the liquid surface 280 by maintaining a desirable and predominately
horizontal velocity component for the gas/liquid mixture flowing
outward over the second end 242 of the weir 240 and along the
surface of the liquid 280 within vessel 230. As illustrated in FIG.
3, the submerged gas processor 210 includes a vessel 230 with a
dished bottom having an interior volume and a vertical gas inlet
tube 222 at least partially disposed within the interior volume of
the vessel 230. In this case, the gas inlet tube 222 has a diameter
of approximately 20 inches and the overall diameter of the vessel
230 is approximately 120 inches, but these diameters may be more or
less based on the design capacity and desired process result as
relates to both gas and liquid flow rates and the type of
combustion device (not shown in FIG. 3) supplying hot gas to the
submerged gas processor. In this example the weir 240 has a
diameter of approximately 40 inches with vertical walls
approximately 26 inches in length. Thus, the weir 240 forms an
annular confined volume 270 within vessel 230 between the inner
wall of the weir 240 and the outer wall of the gas inlet tube 222
of approximately 6.54 cubic feet. In the embodiment of FIG. 3,
twelve sparge ports 224 are disposed near the bottom of the gas
inlet tube 222. The sparge ports 224 are substantially rectangular
in shape and are, in this example, each approximately 3 inches wide
by 71/4 inches high or approximately 0.151 ft.sup.2 in area for a
combined total area of approximately 1.81 ft.sup.2 for all twelve
sparge ports 224. Thus, in this example the ratio of gas flow per
unit sparge port area is approximately 6100 acfm per ft.sup.2 at
the hot gas operating temperature within the gas inlet tube 222, in
this case 1,400.degree. F.
[0036] As will be understood, the combustion gas exits the gas
inlet tube 222 through the sparge ports 224 into a confined volume
270 formed between the gas inlet tube 222 and a tubular shaped weir
240. In this case, the weir 240 has a circular cross-sectional
shape and encircles the lower end of the gas inlet tube 222.
Additionally, the weir 240 is located at an elevation which creates
a lower circulation gap 236 of approximately 4 inches between a
first end 241 of the weir 240 and a bottom dished surface 231 of
the vessel 230. The second end 242 of the weir 240 is located at an
elevation below a normal or at rest operating level of the process
fluid within the vessel 230. Further, a baffle or shield 238 is
disposed within the vessel 230 approximately 8 inches above the
second end 242 of the weir 240. The baffle 238 is circular in shape
and extends radially outwardly from the gas inlet tube 222.
Additionally, the baffle 238 is illustrated as having an outer
diameter somewhat greater than the outer diameter of the weir 240
which, in this case, is approximately 46 inches. However, the
baffle 238 may have the same, a greater or smaller diameter than
the diameter of the weir 240 if desired. Several support brackets
233 are mounted to the bottom surface 231 of the vessel 230 and are
attached to the weir 240 near the first end 241 of the weir 240.
Additionally, a gas inlet tube stabilizer ring 235 is attached to
the support brackets 233 and substantially surrounds the bottom end
226 of the gas inlet tube 222 to stabilize the gas inlet tube 222
during operation.
[0037] During operation of the submerged gas reactor 210, the
combustion gases are ejected through the sparge ports 224 into the
confined volume 270 between the outer wall of the gas inlet tube
222 and the inside wall of the weir 242 creating a mixture of gas
and liquid within the confined volume 270 that is significantly
reduced in bulk density compared to the average bulk density of the
fluid located in the volume 290 outside of the wall of the weir
240. This reduction in bulk density of the gas/liquid mixture
within confined volume 270 creates an imbalance in head pressure at
all elevations between the surface of the liquid 280 within vessel
230 and the first end 241 of the weir 240 when comparing the head
pressure within the confined volume 270 and head pressure within
the volume 290 outside of the wall of the weir 240 at equal
elevations. The reduced head pressure within the confined volume
270 induces a flow pattern of liquid from the higher head pressure
regions of volume 290 through the circulation gap 236 and into the
confined volume 270. Once established, this induced flow pattern
provides vigorous mixing action both within the confined volume 270
and throughout the volume 290 as liquid from the surface 280 and
all locations within the volume 290 is drawn downward through the
circulation gap 236 and upward due to buoyancy through the confined
volume 270 where the gas/liquid mixture flows outward over the
second end 242 of the weir 240 and over the surface of the liquid
280 confined within the vessel 230.
[0038] Within confined volume 270, the induced flow pattern and
resultant vigorous mixing action creates significant shearing
forces that are primarily based on the gross difference in specific
gravity and hence momentum vectors between the liquid and gas
phases at all points on the interfacial surface area of the liquid
and gas phases. The shearing forces driven by the significant
difference in specific gravity between the liquid and gas phases,
which is, generally speaking, of a magnitude of 1000:1 liquid to
gas, cause the interfacial surface area between the gas and liquid
phases to increase significantly as the average volume of each
discrete gas region within the mixture becomes smaller and smaller
due to the shearing force of the flowing liquid phase. Thus, as a
result of the induced flow pattern and the associated vigorous
mixing within the confined area 270, the total interfacial surface
area increases as the gas/liquid mixture flows upward within
confined volume 270. This increase in interfacial surface area or
total contact area between the gas and liquid phases favors
increased rates of heat and mass transfer and chemical reactions
between constituents of the gas and liquid phases as the gas/liquid
mixture flows upward within confined volume 270 and outward over
the second end 242 of the weir 240.
[0039] At the point where gas/liquid mixture flowing upward within
confined volume 270 reaches the elevation of the fluid surface 280
and having passed beyond the second edge 242 of the weir 240, the
difference in head pressure between the gas/liquid mixture within
the confined volume 270 and the liquid within volume 290 fluid is
eliminated. Absent the driving force of differential head pressure
and the confining effect of the wall of the weir 240, gravity and
the resultant buoyancy of the gas phase within the liquid phase
become the primary outside forces affecting the continuing flow
patterns of the gas/liquid mixture exiting the confined space 270.
The combination of the force of gravity and the impenetrable
barrier created by the baffle 238 in the vertical direction
eliminates the vertical velocity and momentum components of the
flowing gas/liquid mixture at or below the elevation of the bottom
of the baffle 238 and causes the velocity and momentum vectors of
the flowing gas/liquid mixture to be directed outward through the
gap 239 created by the second end 242 of the weir 240 and the
bottom surface of the baffle 238 and downwards near the surface of
the liquid 280 within the vessel 230 causing the continuing flow
pattern of the gas/liquid mixture to assume a predominantly
horizontal direction. As the gas/liquid mixture flows outwards in a
predominantly horizontal direction, the horizontal velocity
component continually decreases causing a continual reduction in
momentum and a reduction of the resultant shearing forces acting at
the interfacial area within the gas/liquid mixture. The reduction
in momentum and resultant shearing forces allows the force of
buoyancy to become the primary driving force directing the movement
of the discontinuous gas regions within the gas/liquid mixture,
which causes discrete and discontinuous regions of gas to coalesce
and ascend vertically within the continuous liquid phase. As the
ascending gas regions within the gas/liquid mixture reach the
surface 280 of the liquid within the vessel 230, buoyancy causes
the discontinuous gas phase to break through the liquid surface 280
and to coalesce into a continuous gas phase that is directed upward
within the confines of the vessel 230 and into the vapor exhaust
duct 260 under the influence of the differential pressure created
by the blower or blowers (not shown in FIG. 3) supplying combustion
gas to the submerged gas processor 210.
[0040] FIG. 4 is a top plan view of the submerged gas reactor 210
of FIG. 3 illustrating the tubular nature of the weir 240.
Specifically, the generally circular gas inlet tube 222 is
centrally located and is surrounded by the stabilizer ring 235. In
this embodiment, the stabilizer ring 235 surrounds the gas inlet
tube 222 and essentially restricts any significant lateral movement
of the gas inlet tube 222 due to surging or vibration such as might
occur upon startup of the system. While the stabilizer ring 235 of
FIG. 4 is attached to the support brackets 233 at two locations,
more or fewer support brackets 233 may be employed without
affecting the function of the submerged gas reactor 210. The weir
240, which surrounds the gas inlet tube 222 and the stabilizer ring
235, and is disposed co-axially to the gas inlet tube 222 and the
stabilizer ring 235, is also attached to, and is supported by the
support brackets 233. In this embodiment, the confined volume 270
is formed between the weir 240 and the gas inlet tube 222 while the
second volume 290 is formed between the weir 240 and the side walls
of the vessel 230. As will be understood, in this embodiment, the
introduction of the gas from the exit ports 224 of the gas inlet
tube 220 causes process fluid to flow in an essentially toroidal
pattern around the weir 240.
[0041] Some design factors relating to the design of the submerged
gas processor 210 illustrated in FIGS. 3 and 4 are summarized below
and may be useful in designing larger or smaller submerged gas
processors, which may be used as evaporators or as chemical
reaction devices or both. The shape of the cross sectional area and
length of the gas inlet tube is generally set by the allowable
pressure drop, the configuration of the process vessel, and the
costs of forming suitable material to match the desired cross
sectional area, and, importantly, if direct fired, the
characteristics of the burner that is coupled to the submerged gas
processor. However, it is desirable that the outer wall of the gas
inlet tube 222 provides adequate surface area for openings of the
desired shape and size of the sparge ports which in turn admit the
gas to the confined volume 290. For a typical submerged gas
evaporator, submerged gas reactor or combination submerged gas
evaporator/reactor, the vertical distance between the top edge 242
of the weir 240 and the top edge of the sparge ports should be not
less than about 6 inches and preferably is at least about 17
inches. Selecting the shape and, more particularly, the size of the
sparge port 224 openings is a balance between allowable pressure
drop and the initial amount of interfacial area created at the
point where the gas is dispersed into the flowing liquid phase
within confined volume 290. The open area of the sparge ports 224
is generally more important than the shape, which can be most any
configuration including, but not limited to, rectangular,
trapezoidal, triangular, round, oval. In general, the open area of
the sparge ports 224 should be such that the ratio of gas flow to
total combined open area of all sparge ports should at least be in
the range of 1,000 to 18,000 acfm per ft.sup.2, preferably in the
range of 2,000 to 10,000 acfm/ft.sup.2 and more preferably in the
range of 4,000 to 8,000 acfm/ft.sup.2, where acfm is referenced to
the operating temperature within the gas inlet tube. Likewise, the
ratio of the gas flow to the cross sectional area of the confined
volume 270 should be at least in the range of 200 to 10,000
scfm/ft.sup.2, preferably in the range of 50 to 6,000 scfm/ft.sup.2
and more preferably in the range of 1,000 to 2,500 scfm/ft.sup.2.
Additionally, the ratio of the cross sectional area of the vessel
230 to the cross sectional area of the confined volume 270
(CSA.sub.vessel) is preferably in the range from three to one
(3.0:1) to twelve-hundred to one (1200:1), is more preferably in
the range from five to one (5.0:1) to one-hundred to one (100:1)
and is highly preferably in the range of about ten to one (10:1) to
fourteen to one (14:1). These ratios are summarized in the table
below. Of course, in some circumstances, other ratios for these
design criteria could be used as well or instead of those
particularly described herein.
TABLE-US-00001 TABLE 1 Preferred Ratios Embodiment Acceptable Range
Preferred Range acfm/Total 4,000-8,000 1,000-18,000 2,000-10,000
CSA.sub.sparge ports acfm/ft.sup.2 acfm/ft.sup.2 acfm/ft.sup.2
scfm/ 1,000-2,000 200-10,000 500-6,000 scfm/ft.sup.2
CSA.sub.confined volume scfm/ft.sup.2 scfm/ft.sup.2
CSA.sub.confined volume/ 10:1-14:1 3.0:1-1,200:1 5.0:1-100:1
CSA.sub.vessel
[0042] Turning now to FIG. 5, a submerged gas processor in the form
of a submerged gas reactor 310 is shown which is similar to the
submerged gas evaporator of FIG. 1, and in which like components
are labeled with numbers exactly 300 greater than the corresponding
elements of FIG. 1. Unlike the device 10 of FIG. 1, the submerged
gas reactor 310 of FIG. 5 does not include a pressurized burner
but, alternatively, receives hot gases directly from an external
source, which may be for example, a flare stack, a reciprocating
engine, a turbine, or other source of waste heat. The hot gases
supplied by the external source may include gases having a wide
range of temperature and/or specific components and these hot gases
may be selected by one skilled in the art to achieve any
combination of a rate and degree of chemical reaction between
components in the gas and liquid, a specific rate of evaporation or
to create a specific concentration of the process fluid.
[0043] FIG. 6 illustrates a submerged gas processor 410 which is
similar to the submerged gas processors of FIGS. 1, 2 and 5, in
which like elements are labeled with reference numbers exactly 400
greater than those of FIG. 1. However, the submerged gas reactor
410 includes a jacket 482 at least partially surrounding the vessel
430. The jacket 482 may be used to assist in heating the fluid
within the vessel 430, or alternately in cooling the process fluid
within the vessel 430 as may be desirable to provide for a better
or more complete evaporation process, or to provide for better
reactions, such as chemical reactions or precipitation of
components from the process fluid. Thus, the jacket 482 may be a
heating or a cooling jacket. Alternatively or in addition, the
process fluid may be heated or cooled by other or additional
elements before entering the vessel 430, by recirculation from and
to vessel 430 through other or additional elements external to or
even internal to the vessel 430, or by withdrawal from vessel 430
through other or additional elements external to tank 430. For
heating purposes the jacket 482, other or additional external
elements may be supplied using steam or other heat transfer fluids,
electric resistive heating elements, hot gases, or any other manner
of providing heat. For cooling purposes the jacket 482, other or
additional external elements may be supplied with water or other
cold fluids such as antifreeze solutions or gas. Thus, in one
example, the jacket 482 may allow gases having a wide range of
temperatures to be introduced into and used within the vessel 430
to promote a particular chemical reaction or series of reactions
within the vessel 430 between the gas and the process fluid or to
promote a desired amount of evaporation within the vessel 430. The
gas can be a pure reactant, a mixture of reactants, or a mixture of
reactant gases and diluent gas or gases. In addition, selected
degree of evaporation may be employed in combination with a
chemical reaction or any combination of chemical reactions. Of
course, such heating or cooling jackets may be used in, for
example, the embodiment of the submerged gas processor of FIGS. 1-5
or any other embodiment.
[0044] It will be understood that, because the weir and gas
dispersion configurations within submerged gas processors
illustrated in the embodiments of FIGS. 1-6 provide for a high
degree of mixing, induced turbulent flow and the resultant intimate
contact between liquid and gas within the confined volumes 70, 170,
270, etc., the submerged gas processors of FIGS. 1-6 create a large
interfacial surface area for the interaction of the process fluid
and the gas provided via the gas inlet tube, leading to very
efficient heat and mass transfer between gas and liquid phases
and/or high rates of chemical reactions between components within
these two phases. Furthermore, the use of the weir and, if desired,
the baffle, to cause a predominantly horizontal flow pattern of the
gas/liquid mixture at the surface of the fluid process mixture
mitigates or eliminates the entrainment of droplets of process
liquid within the exhaust gas. Still further, the high degree of
turbulent flow within the vessel mitigates or reduces the formation
of large crystals or agglomerates and maintains the mixture of
solids and liquids within the evaporator/reactor vessel in a
homogeneous state to prevent or reduce settling of precipitated
solids. This factor, in turn, reduces or eliminates the need to
frequently clean the reactor vessel and, in the case of evaporation
processes, allows the process to proceed to a very high state of
concentration by maintaining precipitates in suspension. In the
event that such solids do form, however, they may be removed via
the outlet port 32 (FIG. 1) using a conventional valve
arrangement.
[0045] While a couple of different types submerged gas processors
having different weir configurations are illustrated herein, it
will be understood that the shapes and configurations of the
components, including the weirs, baffles and gas entry ports, used
in these devices could be varied or altered as desired. Thus, for
example, while the gas inlet tubes are illustrated as being
circular in cross section, these tubes could be of any desired
cross sectional shape including, for example, square, rectangular,
oval, etc. Additionally, while the weirs illustrated herein have
been shown as flat plates or as tubular members having a circular
cross-sectional shape, weirs of other shapes or configurations
could be used as well, including weirs having a square,
rectangular, oval, or other cross sectional shape disposed around a
fire or other gas inlet tube, weirs being curved, arcuate, or
multi-faceted in shape or having one or more walls disposed
partially around a fire or gas inlet tube, etc. Also, the gas entry
ports shown as rectangular may assume most any shape including
trapezoidal, triangular, circular, oval, or triangular.
[0046] Still further, as will be understood, the terms submerged
gas reactor, submerged gas evaporator and submerged gas processor
have been used herein to generally describe and to include both
submerged gas evaporators and submerged gas chemical reactors as
well as other devices. As a result, any of the submerged gas
processors described or illustrated herein may be used as
evaporators or as chemical reaction devices or both. Likewise, the
principles described herein may be used on a submerged combustion
gas evaporator or reaction device, e.g., one that combusts fuel to
create the gas, or on a non-combustion gas evaporator or reaction
device, e.g., one that accepts gas from a different source. In the
later case, the gas may be heated gas from any desired source, such
as an output of a reciprocating engine or a turbine, a process
fueled by landfill gas, or any other source of heated gas. Such a
reciprocating engine or turbine may operate on landfill gas or on
other types of fuel. Of course, generally speaking, the submerged
gas processors described herein may be connected to any source of
waste heat and/or may be connected to or include a combustion
device of any kind that, for example, combusts one or a combination
of a biogas, a solid fuel (such as coal, wood, etc.), a liquid fuel
(such as petroleum, gasoline, fuel oil, etc.) or a gaseous fuel.
Alternatively, the gas used in the submerged gas processor may be
non-heated and may even be at the same or a lower temperature than
the liquid or process fuel within the vessel, and may be provided
to induce a chemical or physical reaction of some sort such as the
formation of a desirable precipitate.
[0047] Still further, as will be understood by persons skilled in
the art, the improved submerged gas processors described herein may
be operated in continuous, batch or combined continuous and batch
modes. Thus, in one instance the submerged gas processor may be
initially charged with a controlled amount of liquid to be
processed and operated in a batch mode. In the batch mode, liquid
feed is continuously added to the submerged gas processor to
maintain a constant predetermined level within the process vessel
by replacing any components of the process fluid that are
evaporated and/or reacted as the process proceeds. Once the batch
process has reached a predetermined degree of concentration,
completeness of a chemical reaction, amount or form of precipitate,
or any combination of these or other desirable attributes, the
process may be shutdown and the desirable product of the process
may be withdrawn from the submerged gas processor for use, sale or
disposal. Likewise, the submerged gas processor may be initially
charged with a controlled amount of liquid to be processed and
operated in a continuous mode. In the continuous mode, liquid feed
would be continuously added to the submerged gas processor to
maintain a constant predetermined level within the process vessel
by replacing any components of the process fluid that are
evaporated and/or reacted as the process proceeds. Once the fluid
undergoing processing has reached a predetermined degree of
concentration, completeness of a chemical reaction, amount or form
of precipitate, or any combination of these or other desirable
attributes, withdrawal of process fluid at a controlled rate from
the process vessel would be initiated. The controlled withdrawal of
process fluid would be set at an appropriate rate to maintain a
desirable equilibrium between the rate of feed of the liquid and
the gas, the rate of evaporation of components from the process
liquid, and the rate at which the desired attribute or attributes
of the processed fluid are attained. Thus, in the continuous mode,
the submerged gas processor may operate for an indeterminate length
of time as long as there is process feed liquid available and the
process system remains operational. The combined continuous and
batch mode refers to operation where, for instance, the amount of
available feed liquid is in excess of that required for a single
batch operation, in which case the process may be operated for
relatively short periods in the continuous mode until the supply of
feed liquid is exhausted.
[0048] While certain representative embodiments and details have
been shown for purposes of illustrating the invention, it will be
apparent to those skilled in the art that various changes in the
methods and apparatus disclosed herein may be made without
departing from the scope of the invention, which is defined in the
appended claims.
* * * * *