U.S. patent application number 11/761773 was filed with the patent office on 2008-03-13 for handling and extracting hydrocarbons from tar sands.
Invention is credited to Paul Wegner.
Application Number | 20080060978 11/761773 |
Document ID | / |
Family ID | 38669455 |
Filed Date | 2008-03-13 |
United States Patent
Application |
20080060978 |
Kind Code |
A1 |
Wegner; Paul |
March 13, 2008 |
HANDLING AND EXTRACTING HYDROCARBONS FROM TAR SANDS
Abstract
A method and system for handling tar sands and extracting
bitumen or oil from the tar sands. The method includes the steps of
depositing tar sands in a hopper assembly having a conical bottom.
An organic solvent mixture is sprayed on the tar sands through a
series of jets near the walls of the hopper. The oil or bitumen in
the tar sands is dissolved by the organic solvent mixture. Sand
from the tar sands is allowed to separate and fall toward the
bottom of the hopper assembly. The sands and liquid in a slurry of
fluid are transported from the hopper assembly to a rinse chamber.
The slurry of fluid is delivered into the top of the rinse chamber
tangentially to cause cyclonic action of the slurry in the rinsing
chamber. Solvent introduced at the bottom of the rinse chamber and
the solvent mixture is drawn from the top of the rinse chamber.
Thereafter, the solvent and hydrocarbon liquid mixture is pumped to
a separator in order to separate the oil and bitumen from the
solvent. Finally, the clean solvent is returned to be reused by
introduction into the rinse chamber in order to form a closed loop
process.
Inventors: |
Wegner; Paul; (San Carlos,
CA) |
Correspondence
Address: |
HEAD, JOHNSON & KACHIGIAN
228 W 17TH PLACE
TULSA
OK
74119
US
|
Family ID: |
38669455 |
Appl. No.: |
11/761773 |
Filed: |
June 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60804781 |
Jun 14, 2006 |
|
|
|
Current U.S.
Class: |
208/390 |
Current CPC
Class: |
B01D 11/0223 20130101;
C10G 1/04 20130101; B01D 11/0288 20130101; B01D 11/0296
20130101 |
Class at
Publication: |
208/390 |
International
Class: |
C10G 1/04 20060101
C10G001/04 |
Claims
1. A method for handling tar sands and extracting bitumen or oil
from said tar sands, which method comprises: depositing tar sands
into a hopper assembly: contacting an organic solvent mixture with
said tar sands in said hopper assembly; dissolving said oil or
bitumen in said tar sands with said organic solvent; allowing sand
from said tar sands to separate and fail toward a bottom of said
hopper assembly; transporting said separated sands and said liquid
in a slurry of fluid from said hopper assembly to a top of a rinse
chamber; delivering said slurry of fluid into a top of said rinse
chamber tangentially to cause cyclonic action of the slurry in said
rinsing chamber to separate said sands from said fluid; drawing and
removing said solvent and said oil or bitumen mixture from said
rinse chamber; drawing said solvent and said oil/bitumen mixture to
a separator to separate said oil/bitumen from said solvent; and
returning said solvent to said hopper assembly to be reused to form
a closed loop process.
2. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 wherein said hopper has a conical bottom.
3. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 including the additional step of separating
solids below a certain size with a perforated screen in said hopper
assembly above said conical bottom.
4. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 including maintaining an inert gas blanket at
a top of the hopper assembly.
5. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 wherein said separated sands from said rinsing
chamber are heated to remove solvent.
6. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 5 wherein said separated sands are heated by
steam heat.
7. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 wherein said organic solvent is heated in a
heat exchanger prior to said step of providing on said tar
sands.
8. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 including maintaining a layer of said tar sand
above an area where organic solvent contacts said tar sand to
maintain a vapor absorption barrier.
9. A method for handling tar sands and extracting bitumen or oil as
set forth in claim 1 wherein said organic solvent is a mixture of
hexane and bitumen.
10. A method for handling tar sands and extracting bitumen or oil
as set forth in claim 1 including maintaining liquid spring line in
said hopper assembly.
11. A method for handling tar sands and extracting bitumen or oil
as set forth in claim 1 including maintaining a liquid spring line
in said rinse chamber.
12. A method for handling tar sands and extracting bitumen or oil
as set forth in claim 1 including maintaining a common liquid
spring line in both said hopper assembly and said rinse
chamber.
13. A method for handling tar sands and extracting bitumen or oil
as set forth in claim 1 including maintaining less than atmospheric
pressure in said rinse chamber.
Description
CROSS-REFERENCE OF RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 60/804,781, filed Jun. 14, 2006.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is directed to a method and apparatus
for handling tar sands and extracting bitumen or oil from tar sands
in an economical and efficient continuous closed loop system.
[0004] 2. Prior Art
[0005] Tar sands, sometimes known as oil sands or bituminous sands,
are a combination of clay, sand, water and bitumen. Bitumen is a
semisolid form of oil. It is known to mine tar sands to extract the
bitumen, which is upgraded into synthetic crude or refined directly
into petroleum products.
[0006] Tar sands deposits are found in over 70 countries throughout
the world and represent as much as two-thirds of the world's
reserves of oil.
[0007] In the processing of tar sands which contain oil-bearing
bitumen, the oil-bearing sands must first be mined, the tar sand
processed and the sand cleaned sufficiently to alleviate
environmental concerns upon disposal or proper placement back into
the environment.
[0008] There are various known methods of extracting the bitumen or
oil from the tar sands. In one known process, the tar sands are
mined and hot water and caustic soda (NaOH) are added to the sand.
The resulting slurry is piped to an extraction plant where it is
agitated and the oil skimmed from the top.
[0009] In an alternate known cold flow process, oil is pumped out
of the sands using progressive cavity pumps which lift oil along
with sand. This process only works well where the oil or bitumen is
fluid enough to pump.
[0010] In an alternate known cyclic steam stimulation process, a
well is put through cycles of steam injection, soaking, and oil
production. Oil or bitumen is thereby extracted.
[0011] U.S. Pat. No. 5,998,640 to Haefele et al. discloses a
solvent extraction method that utilizes pressure to assist the
extraction. By providing a pressure differential, oil free solids
may be removed from an oil extraction chamber.
[0012] A large portion of the expense of tar sand processing is
materials handling. The material is sticky, and tough. Conveyors,
augers, and crushers wear quickly when handling tar sand. Solvent
extraction processes are usually considered to be energy intensive
and solvent loss is often an issue. The extraction efficiencies are
normally no greater than 85%. In addition, cold weather can shut
down most operations.
[0013] In order for the extraction of tar sands to be an economical
endeavor, the separation process should ideally be low energy,
provide a simple material handling method, and recycle most of the
chemicals added for processing.
[0014] The present invention also addresses issues concerning
energy recycling and solids handling.
[0015] Accordingly, it is a principal object and purpose of the
present invention to utilize tar sands as a source of cooling for a
solvent condenser.
[0016] It is a further object and purpose of the present invention
to provide a handling and extraction system that does not require
crushing.
[0017] It is a further object and purpose of the present invention
to use an oil/solvent mixture to dissolve, transport and classify
the tar sands.
[0018] It is a further object and purpose of the present invention
to provide a continuous handling and extraction process at
atmospheric pressure in a closed loop system.
SUMMARY OF THE INVENTION
[0019] The present invention is directed to a process and a system
for handling and extracting hydrocarbon liquids from tar sands.
Initially, the tar sands are deposited into an open top hopper
assembly. The hopper or dissolution chamber may include a source of
an organic solvent liquid mixture on the incoming tar sands. The
mixture dissolves the oil or bitumen in the tar sands. Prior to
entry into the dissolution chamber, the solvent will be heated by
being passed in heat exchange relationship in a solvent heat
exchanger.
[0020] The tar sand is introduced at the top of the hopper. Below
there is a inert gas blanket (inert blank zone A) is created by
introduction of a inert gas such as nitrogen or cooled combustion
exhaust to displace oxygen from the tar sand. This prevents oxygen
from entering into the process. The layer of tar sand underneath
the inert gas blanket acts as a solvent vapor absorbing media.
Since fresh tar sand is introduced on a continuous basis new
absorption media constantly replenishes the absorption layer
(absorption zone B) Therefore, this layer never becomes saturated
with solvent vapor. As an added insurance to prevent solvent vapor
incursion into zone A, solvent vapor sucked out in a downward
fashion through zone B. The solvent vapor inert gas mixture exhaust
can be treated with a gas scrubber. The layer below is dissolved by
contacting the tar sand with a warm solvent oil mixture (leach zone
C). The resultant sand slurry passes the through a screen basket
which retains rock, gravel, and coarse sand. This basket is emptied
when it becomes full. The sand slurry combines with the
recirculation loop fluid in mixing T 28.
[0021] Solvent vapors are prevented from leaving the dissolution
chamber by a closed loop system. Solvent laden gas is drawn into
ducts and removed and pumped to a chiller unit which assists in
converting vaporized solvent to liquid.
[0022] Solvent vapors are prevented from leaving the dissolution
chamber by having a layer of tar sands (absorption zone B) and by a
closed loop system . . . to liquid. Any remaining vapors are
stripped out with a gas scrubber.
[0023] The mixture of fine sand and liquid containing solvent and
oil or bitumen is then transported from the base of the hopper to a
rinse chamber in a fluid slurry. The slurry enters into a
tangential cyclone port near the top of the rinse chamber.
Centrifugal force will cause the sand to separate from the solvent.
Slurry liquid gathers at the center and top of the rinse chamber
while the sand moves downward in the rinse chamber.
[0024] A portion of the recirculating solvent and hydrocarbon
liquid mixture is drawn off from the recirculation line to a pump
where it is sent into a further cyclone separator to further polish
off or remove small solid particles such as sand. The fluid which
is free of sand is then pumped to two heat exchangers. Steam is
circulated into the heat exchangers. As the combination solvent and
liquid hydrocarbons are heated, the solvent will vaporize before
the oil or bitumen to be recovered. The vaporized solvent will pass
to the top of the heat exchangers to a vapor collection chamber
where the vapors are directed to a condenser to condense the clean
solvent vapors into liquid solvent. The liquid solvent is
thereafter directed back to a solvent storage tank for clean
solvent. A portion of the solvent vapors directed through port (26)
to the recirculation loop heat exchanger (22) to provide indirect
heat to the recirculation loop solvent oil mixture, while the
balance is directed to the condenser.
[0025] A shaft assembly in the rinse chamber may include a motor or
motors. The shaft assembly and motors rotate a first tray in a
first direction against the series of stationary plows. Downward
progression of the sand in the rinse chamber is facilitated by the
relative motion of the plows relative to the rotating tray.
Rotation of the first tray relative to the plows tends to lift the
solvent saturated sand upward out of the bowl of the first tray
above the fluid line so that the sand moves to the second tray. The
sand residing in the second tray is heated both indirectly and
directly with steam and direct steam injection. The heated sand
which no longer contains liquid solvent has the remaining solvent
vapors displaced with an inert gas (200) The solvent free sand will
fall by gravity to a rotary valve where it is permitted to exit
through the duct which has a inert gas blanket to prevent oxygen
from entering the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a simplified diagrammatic view of a system of
handling and extracting hydrocarbons from tar sands constructed in
accordance with the present invention;
[0027] FIG. 2 is an enlarged view of a cyclone separator and rinse
chamber used as a part of the system shown in FIG. 1;
[0028] FIG. 3 is a sectional view taken along section line 3-3 of
FIG. 2; and
[0029] FIG. 4 is a diagrammatic sequential flow chart of the system
shown in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0030] The embodiments discussed herein are merely illustrative of
specific manners in which to make and use the invention and are not
to be interpreted as limiting the scope of the instant
invention.
[0031] While the invention has been described with a certain degree
of particularity, it is to be noted that many modifications may be
made in the details of the invention's construction and the
arrangement of its components without departing from the spirit and
scope of this disclosure. It is understood that the invention is
not limited to the embodiments set forth herein for purposes of
exemplification.
[0032] The present invention is directed to a method and apparatus
for handling and extracting oil from tar sands. The tar sands
material is initially gathered or excavated from a deposit in
various ways which are not a part of the invention. For example,
the material is peeled off the tar sand deposit and dumped directly
into an oil extraction or hopper assembly as large chunks sized
from approximately 1/4 to 12 inches (1/4'' to 12''). While
occasional large rocks may be crushed or removed, a key feature of
the present invention is that the tar sands generally do not have
to be crushed as a part of the process.
[0033] Referring to the drawings in detail, FIG. 1 illustrates a
schematic diagram of a system 10 of handling and extracting
hydrocarbon from tar sands.
[0034] The system 10 may be located near a tar sands deposit so
transportation and handling costs are low. In one embodiment, the
tar sands 13 are initially peeled off a deposit in sheets, such as
one foot wide sheets. The tar sands material 13 is then dumped into
an oil extraction hopper or dissolution assembly 12. The hopper
assembly 12 may be configured as an open topped cylinder or an open
topped cone.
[0035] The hopper consist of four zones The inert gas blanket zone
(zone A) which prevents oxygen from entering the hopper by
providing a constant flow of inert gas such as nitrogen or
combustion exhaust into this zone. The solvent absorption zone
(zone B) where the continued introduction fresh tar sands into this
zone absorbs any solvent vapors escaping from the leach zone. In
leach zone (zone C) a heated solvent/oil mixture contacts the tar
sand by one or more sources. The rock basket (optional) which
prevents rocks, gravel and coarse sand from entering the mixing T
(18) In this area solvent vapor maybe removed by a vacuum pump to
retard the migration of vapor into zone A.
[0036] The hopper or dissolution chamber 12 may include a source 8
near the outer walls of the cone which provides an organic solvent
liquid mixture, such as a hexane or pentane with bitumen, on the
incoming tar sands as depicted by arrows 6. The solvent/bitumen
mixture dissolves the oil or bitumen in the tar sands. It will be
appreciated that other solvents may be utilized within the spirit
and scope of the present invention.
[0037] Solvent is introduced to the dissolution chamber 12 from a
solvent recirculation loop 14. The flow of solvent controls the
rate and how well the nonporous rocks are washed. The flow of
solvent and oil out through a mixing T 18, determines the
concentration of sand transported to the rinse chamber (to be
described) as a slurry. In one preferred iteration, a concentration
of 5% sand in the outgoing slurry is acceptable.
[0038] Prior to entry into the dissolution chamber 12, the solvent
will be heated by being passed in heat exchange relationship in a
solvent heat exchanger 22.
[0039] Solvent vapors and/or solvent are introduced into the heat
exchanger as shown at arrow 24. Steam maybe used but it is less
desirable. Solvent vapor and condensate exits heat exchanger 22 as
shown at arrow 26.
[0040] The mid portion of the hopper or dissolution chamber 12
contains sources 6 which are below the surface of the deposited tar
sand. The solvent/bitumen mixture dissolves the oil or bitumen in
the tar sands. The eroded sand from zone C falls to the bottom of
the hopper 12 above the conical base of the hopper 12.
[0041] The sand flows through the rock basket which retains the
rock etc while passing the sand to the bottom of the dissolution
chamber.
[0042] The upper portion of the hopper 12 acts like a leach field
in which the oil is leached from the tar sand. Once the oil and
bitumen is dissolved, the sand flows to the bottom of the
dissolution chamber.
[0043] As an option, a perforated screen (not shown) may be
employed spaced above the conical base of the dissolution chamber.
The perforated metal screen or grating only allows fully eroded
sand to pass onto the rinse chamber for further processing. In that
case, the tar sand will not enter the slurry transport system until
it is small enough to pass through the perforated metal screen.
[0044] A valve 28 modulates the flow of oil solvent to leach zone C
which controls the rate of sand erosion in the leach zone which in
turn determines the rate sand flowing to mixing T 18.
[0045] Vapors are prevented from leaving the top dissolution
chamber 12 by removing vapors from rock basket area. This retards
the upward migration of vapor through vapor absorption zone B
towards the top of the hopper shown by arrow 15. Near the bottom of
the hopper 12, solvent laden gas is drawn into ducts 36 and removed
and pumped with gas pump 30 to a chiller unit 32 which assists in
converting the vaporized solvent in to liquid. This followed by a
gas scrubber unit. The resulting gas is directed to the bottom of
conical tray 108 through port 200
[0046] The dissolution chamber 12 reduces or eliminates the need
for a crusher and insures a high level of extraction. Surface oil
is effectively removed from rocks occurring in the tar sand. Since
the flow solvent is functioning in lieu of the crushing agent,
there is little to wear out in the system.
[0047] The present invention uses the oil/solvent mixture to wash
the tar sands in lieu of a crusher. This has several benefits. The
oil/solvent mixture only dissolves oil/sand aggregates, while
leaving the non oil bearing rocks essentially untouched. Moreover,
the hot oil/solvent mixture heats up the tar sand to maximize the
dissolution speed.
[0048] In many cases, the majority of the tar sand has a particle
size of less than 1/16 of an inch. At this particle size, the
washing of the oil and bitumen from the tar sand is rapid and
efficient. The oil/solvent fine sand mixture provides an ideal
mixture for easy transport of the mixture at the mining site to the
wash chamber and desolventization chamber. The combination
oil/solvent provides the proper amount of viscosity, lubrication,
and density to facilitate the transport of the dissolved tar sand
as slurry through a pipe. These features eliminate the crushing
operation and expensive transport tar sand from the mining pit to
the processing area.
[0049] The mixture of fine sand and liquid containing solvent and
oil or bitumen, is then transported from the base of the hopper 12
to near a top of a rinse chamber 40 in a pipe as a fluid slurry.
The liquid oil or bitumen is then harvested from the rinse chamber
14 as will be described herein. The slurry enters into a tangential
cyclone port 54 located at the top of the rinse chamber 40. Since
only fine sand particles are allowed to enter, the slurry line
transportation is simple and uniform. Since the slurry is pumped
into the rinse chamber 40, centrifugal force will cause the sand to
separate from the solvent as illustrated by arrows 42. Once the
sand enters the rinse chamber, the cyclone action of the rinse
chamber configuration allows most of the sand to be removed from
the oil solvent mixture before returning to the recirculation line
44 where it is recirculated back to the nozzles previously
described and the motive power for the oil solvent sand mixture
transport. Then the oil solvent mixture flows through the
dissolution chamber ports and returns to cyclone intake port.
[0050] Since the sand is removed prior to returning to the
recirculation pump, wear issues are minimized for the pump and
spray nozzles.
[0051] The slurry enters the top of the rinse chamber 40
tangentially which causes a cyclonic action within the rinsing
chamber 40. Due to centrifugal force, slurry liquid gathers at the
center of the rinse chamber while the sand in the slurry moves
toward the outer walls of the rinse chamber.
[0052] By the time the tar sands reach the rinse chamber 40, the
vast majority of oil is dissolved out of the tar sands. The
remaining oil is removed by displacement washing. The rinse chamber
40 configuration allows oil solvent mixture to be removed from the
rinse chamber on a continuous basis as a dirt free oil and solvent
mixture. A mass flow meter measures the density of the mixture
continuously such that oil solvent which is harvested maintains a
constant concentration of oil. This permits uniform processing
conditions independently of pay dirt oil concentration.
[0053] Oil free solvent is also introduced at and pumped to the
bottom of the rinse chamber 40. As the dissolved sand progresses
down the rinse chamber 40, the solvent progresses up the chamber in
a counter current fashion as shown by arrows 56.
[0054] Solvent is removed via recirculation line 44 and moved by
pump 43 in a loop past the connection with the dissolution chamber
12 mixing T 18.
[0055] A portion of the recirculating solvent and hydrocarbon
liquid mixture is drawn off from the recirculation line 44 via line
46 to a pump 48 where it is sent into a further cyclone separator
50. The cyclone separator 50 serves to further polish off or remove
small solid particles, such as sand, which are returned to the
recirculation line 44.
[0056] The fluid which is free of sand is then pumped via line 52
to two heat exchangers 60 and 62. Steam is circulated into heat
exchangers 60 and 62 through inputs 64 and 66 and then out
therefrom through outputs 68 and 70. It will be appreciated that
one or more heat exchangers may be employed within the spirit and
scope of the invention.
[0057] As the combination solvent and liquid hydrocarbons are
heated in the heat exchangers 60 and 62, the solvent will vaporize
before the oil or bitumen to be recovered. Accordingly, as shown by
arrows 58, the vaporized solvent will pass to the top of the heat
exchangers 60 and 62 to a vapor collection chamber 72 where a
portion of the vapors are directed to line 24 to recirculation heat
exchanger 24, while the remaining vapors from duct 79 and 26 are
directed to condenser 74. The liquid solvent is thereafter directed
via line 76 back to a solvent storage tank 78 for clean
solvent.
[0058] At the same time, the liquid which is primarily hydrocarbon
oil and bitumen is drawn off via lines 77 to oil storage tank
75.
[0059] The interior of the rinse chamber is kept at a pressure less
than atmospheric pressure which eliminates any need for a
depressurization chamber for removing desolventized sand from the
process. This, in turn, permits continuous production of
desolventized sand without interruption. Accordingly, the
desolventization or rinse chamber 40 is kept at atmospheric
pressure or less to prevent solvent vapors from leaving the
desolventized sand exit port.
[0060] Turning to a consideration of FIG. 2 which shows a portion
of the rinse chamber 40, and continuing consideration of the system
10 in FIG. 1, a siphon chamber 80 is provided surrounding the rinse
chamber 40 and is in fluid communication therewith. In the
preferred embodiment shown, the siphon chamber 80 substantially
circumnavigates the rinse chamber. The siphon chamber 80 is
connected via line or lines 82 and 84 to the gas pump 30 which
insures that a vacuum will be provided to the siphon chamber 80.
Liquid solvent is provided from the solvent storage tank 76 via
line 86 to the siphon chamber by action of a pump 38.
[0061] At the same time, solvent is allowed to travel via line 88
to an excess solvent chamber 90 whereby solvent is allowed to pass
as shown by arrows 92 into an inner container 95 having an open top
and return via line 94 to the liquid solvent storage tank 76. The
level of the open top of the inner container 95 is adjustable by
handle 93. The solvent level 97 in the rinse chamber 40 and in the
excess solvent chamber 90 is maintained at a level as shown by
arrows 96.
[0062] The vapor pressure equalization line 202 insures the
pressure is the same between desolventization zone of the rinse
chamber and the excess solvent chamber 90. Without this feature the
level control system will not work, if the desolventization area
has a pressure which is different from the siphon overflow chamber
90.
[0063] The same level of solvent is also maintained above the
mixing T 18 of the hopper assembly so that the siphon will not be
broken between the rinse chamber and the hopper T. The hopper T is
located at a position low enough that gases are not sucked into the
recirculation loop which could break the siphon.
[0064] A shaft assembly 100 may include a motor or motors 102 and
104. In a preferred embodiment, hydraulic motors are employed at
the top of chamber 40. The shaft assembly and motors rotate a first
conical tray 106 in a first direction against a series of
stationary plows 98. In one non-limiting embodiment, the first tray
is rotated approximately 10 revolutions per minute (rpm).
[0065] The shaft assembly 100 will also rotate a second conical
tray 108, which is coaxial therewith, in an opposite direction from
rotation of the first tray. As best seen in the sectional view in
FIG. 3, extending from the second tray is a series of blades 99. In
one preferred embodiment, the shaft assembly includes a shaft
within a shaft to rotate the first and second tray.
[0066] Downward progression of the sand in the rinse chamber is
facilitated by the relative motion of the plows 98 relative to the
rotating tray 106. It will be appreciated that either the bowl or
the trays may rotate. The rotation of the first tray 106 relative
to the plows 98 tends to lift the solvent saturated sand upward out
of the bowl of the first tray above the fluid line 96 so that the
sand moves to the second tray 108. The sand residing in the second
tray 108 is heated directly and indirectly with steam. Steam heat
is applied to a chamber 110 via inlet 112 and is circulated
therefrom via outlet 114. The sand will tend to vaporize the
solvent which is drawn off to chamber 122 via line 116 to duct 79.
The clean sand with the solvent removed will fall by gravity to a
valve 124 with rotating paddles.
[0067] As best seen in FIG. 1, as the valve paddles rotate, the
clean sand will exit the system as shown by arrow 118 and may be
transported by any mechanism, such as by conveyor 120.
[0068] The bird feeder style P-trap allows removal of the rinsed
tar sand from the bottom of the rinse chamber in a controlled
manner with a minimum amount of solvent associated with the sand.
The rinse chamber 40 is arranged such that the liquid level is
maintained by a siphon tube arrangement. The siphon is established
by introducing a vacuum at the top of the chamber to remove all
gases from the upper rinse chamber and siphon tube areas.
[0069] The system will operate as a closed loop process. A key to
starting the system up is establishing a siphon system. Solvent
must be introduced into the bowl of the rinse chamber 40 and mixing
T 28 to create a P trap seal which allows the siphon loops to be
created. The solvent can be introduced via the recirculation pump
loop and the siphon pump loop. Once the siphons are established,
the solvent is supplied through the siphon pump loop.
[0070] In the case of the recirculation loop, once a seal is
initiated, a vacuum is placed on the rinse chamber 40 to keep the
solvent level near the top of the rinse chamber 40. The siphon pump
is turned on to insure the solvent level in the bowl remains
constant. This is accomplished by siphon overflow stand pipe and a
flow meter. The pump speed is adjusted such that the standpipe
overflow is equal to or greater than zero. The rinse chamber 40 and
the recirculation pump loop fill with solvent. Once the
recirculation loop and rinse chamber is full of solvent, the siphon
loop is established and application of a vacuum is no longer
required as long as air does not enter the upper portion of the
rinse chamber. In this case, vacuum valve is open to remove the air
trapped in the upper portion of the rinse chamber. Once the siphon
loop is established, the recirculation pump may be started. The
siphon loop allows the solvent level to remain constant in the
dissolution chamber even when the solvent recirculation pump is
off. This feature also allows for the continuous introduction of
tar sands into the dissolution chamber without interruption. The
tar sand in the dissolution chamber is gradually dissolved and
transported to the rinse chamber as slurry. The amount of flow
through the bottom T and the upper portion of the dissolution
chamber is modulated to maintain the proper level solvent in the
dissolution chamber to prevent the entrainment of air into the
recirculation loop and the level solvent from getting too high in
the dissolution chamber.
[0071] The fresh solvent used to displacement wash sand in the
rinse chamber 40 is added around the bottom perimeter of the rinse
chamber 40 by an annular ring. The annular ring of solvent is
contained by the lower wall of the rinse chamber and a tube on the
outside of the chamber, which is sealed between the rinse chamber
wall and the top of outside tube. This annular ring is also
controlled by a siphon tube.
[0072] The rate of clean sand removal from the rinse chamber 40 is
dictated by the plow configuration and the number and movement of
the plows relative to the sand. The movement of the plows relative
to the sand is achieved by the rotation of the plow or the bowl,
which forms the annular P trap.
[0073] FIG. 4 illustrates a simplified schematic diagram of the
procedure to handle and extract hydrocarbons from tar sands.
Initially, the hopper assembly 12 is loaded with tar sand and
solvent is injected or sprayed onto the incoming tar sand as shown
by box 130. Through use of the gas pump 30 and closed loop system,
a vacuum is applied in order to assist in keeping the level of
solvent at a desired level as shown at box 132.
[0074] Once the recirculation loop, rinse chamber and siphon pump
loop are full of solvent, the application of vacuum is no longer
required as long as gases to do not enter the upper portion of the
rinse chamber or the siphon pump loop in sufficient quantities to
break either of these siphons. In this case, a vacuum valve is open
to remove the gases trapped in the upper portion of the rinse
chamber or the siphon pump loop.
[0075] After the solvent contacts the tar sands in the hopper
assembly, the slurry of solvent, hydrocarbon liquids, and small
sand particles are transported in a slurry to the rinse chamber as
shown at box 134. Liquid solvent and hydrocarbon liquid is
thereafter drawn off from the rinse chamber by force of the
recirculation pump shown at box 136 and directed to the
recirculation loop heat exchanger. A portion of the liquid is
removed by an oil solvent pump and transported to solvent/oil heat
exchanger. The hydrocarbon oil and bitumen are harvested and
delivered to a storage tank 75 as shown at box 140. The solvent, in
the form of vapors, are drawn off and condensed as shown at box 142
and also pumped back to the rinse chamber as shown at box 144.
[0076] The sand at the base of the rinse chamber is delivered to
the steam heating tray or cone where the sand and solvent therein
are heated, as shown at box 148. The solvent vapors are delivered
back to the solvent condenser 142 while the clean sand which is
tree of hydrocarbon oil and solvent is removed from the rinse
chamber as shown at box 146.
[0077] The invention uses the tar sands themselves as the cooling
source for condensing the solvent which is vaporized from the clean
sand. The heat of condensation is used to heat up the incoming tar
sand. This is accomplished by using an oil/solvent recirculation
pump. The oil/solvent is pumped through the cooling side of the
heat exchanger box 150. The solvent condenses on the heating side
of the heat exchanger. The hot oil/solvent mixture is introduced
onto the cold tar sand. The heat is transferred to the tar sand.
The oil mixture continues through the recirculation loop and
eventually returns to the heat exchanger to be reheated. The
recirculation loop heat exchanger can maintain a temperature
approaching the condensation temperature of the solvent.
[0078] In this manner, the majority of energy for heating the tar
sands is provided by this heat exchanger loop and a significant
portion of the cooling requirement is provided by the heat
exchanger. In some cases, the heating requirements for the sand are
about the same as the condensation requirements.
[0079] An additional benefit of this approach is that the hot
oil/solvent mixture increases the dissolution rate of the tar sand
regardless of incoming tar sand temperature.
[0080] The second aspect of this invention is dissolution,
classification, and transport of the tars sand through the process
on a continuous process. A considerable amount of expense is
normally incurred during the mining, transport, and crushing of tar
for processing. In addition, the degree of extraction is a function
of the size of the oil bearing sand agglomerates. Traditionally,
this is dealt with through the use of a crusher. Crushers are
expensive to buy, maintain, and operate. They are prone to jamming
and the wear on the crush hammers is extensive. In addition, they
are not selective in the crushing process and do not separate the
oil bearing sand from the nonporous rock which typically accompany
the tar sand. Crushers usually process the tar sand at ambient
conditions or with the addition of heat. Cold tar sand is less
sticky but harder to crush into small particles. As the particle
size requirement falls below one inch the energy and cost of
operation grows rapidly.
[0081] Whereas, the present invention has been described in
relation to the drawings attached hereto, it should be understood
that other and further modifications, apart from those shown or
suggested herein, may be made within the spirit and scope of this
invention.
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