Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02665751 2009-05-12
INTEGRATED STEAM GENERATION PROCESS FOR ENHANCED OIL
RECOVERY.
Field of the Invention
This application relates to a system and method for producing steam for
Enhanced Oil
Recovery (EOR) facilities. This new invention relates to processes for
producing steam from any
type of fuel, including low quality, solid fuels like petcoke or coal and any
water source without
any water treatment like brackish water containing high levels of dissolved
and suspended
inorganic solids or organics, such as oil.
The invention includes an atmospheric or pressurized solid fuel boiler package
with low
pressure and temperature water distillation package for the production of pure
steam for injection
into the underground formation to recover heavy crude oil. The injection of
steam into heavy oil
formations and especially oils and formation was proven to be an effective
method for EOR and
it is the only method currently used for recover bitumen from deep underground
oils and
formations in Canada. It is known in previous applications that EOR can be
utilized to recover
bitumen where the combustion gases are injected into the formation. The
problem with that
approach is that the oil producers are reluctant to implement significant
changes, especially if
they include changing the composition of gas injected to the underground
formation. This
problem was solved in this application with the use of "commercially
available" steam boilers
and water treatment facilities together with the DCSG (Direct Contact Steam
Generation) and
maintaining most of the advantages of the DCSG for the overall process in the
integrated system
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as described herein.
By integrating the boiler, the distillation facility and the other process
units as described
in this application, the water and combustion gas are separated with Zero
Liquid Discharge. A
ZLD facility is more environmentally friendly compared to a system that
generates reject water
and sludge. In one embodiment, most of the water vapor and the produced heat
is recovered and
used to generate distilled water for additional steam production. The system
might also include a
direct contact brine evaporator dryer (siniilar to DCSG), a dry solids removal
system (to remove
them from the gas stream), and a wet steam generator, (a scrubbing vessel for
scrubbing solids,
sulfur and generating wet steam). The boiler can be a low efficiency boiler
(without economizer)
as the heat of the discharged combustion gas is used in the direct contact
dryer and in the direct
contact wash vessel to evaporate water.
The brine from the distillation facility can be recycled to a liquid
evaporator and dryer
where additional steam is generated and dry solid wastes will be removed from
the produced gas
in a commercially available gas-solid separation unit.
The invention method and system for producing steam for extraction of heavy
bitumen
including the steps of mixing fuel with an oxidizing gas. Combusting the
mixture and capturing
portion of the combustion heat for generating steam from clean water. Mixing
the combustion
gas with low quality contaminated water and transferred the liquid water to
gas phase with
solids, wherein solids are separated from the gas phase. The gas phase is
mixed with saturated
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water to scrub the remaining solids and produce saturated steam. The solid
rich saturated water is
recycled back and mixed with the combustion gases for liquid gasification. The
saturated steam
is condensed to generate heat and clean condensed water for steam generation.
The heat can be
used for evaporating additional low quality water at distillation facility to
produce distilled water
and concentrate brine. The brine is recycled back for liquid gasification. The
high pressure steam
is sent to an enhanced oil recovery facility for extract heavy oil.
The above-mentioned invention also relates to processes for making SAGD and
CSS
facilities or other EOR facilities more environmentally friendly by using low
quality fuels, like
petcoke or coal instead of natural gas. It reduces the amount of greenhouse
gas emissions
through thermal efficiency. The generated CO2 gas can be recovered for
underground
sequestration or for usage in EOR.
BACKGROUND OF THE INVENTION
Steam injection into deep underground formations has proven to be an effective
method
for EOR facilities producing heavy oil. It is typically done through SAGD
(Steam Assistant
Gravity Drainage), Steam Drive or by Cyclic Steam Stimulation (CSS). In recent
years, the
SAGD method has become more popular, especially for heavy oil sand formations.
Presently,
different forms of steam injection are the only method commercially used on a
large scale for
recovering oil from oil sands formations.
The use of DCSG (Direct Contact Steam Generator) to generate high pressure
steam and
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flue gas mixture has many advantages; however it might have some significant
disadvantages
resulting from the presence of the combustion gases, mainly C02, within the
steam. That might
present a problematic situation when used in combination with particular types
of underground
formations and recovery processes.
It is a goal of the present invention to provide a system and method for the
improvement
of EOR facilities like SAGD, through a supply of high - pressure steam for
underground
injection wells.
It is another objective of the present invention to provide a system that can
produce steam
from distilled water and the brine produced by the distillation facility
without liquid discharge.
Another objective of the invention is to provide a system and method that
utilizes low-
grade fuel with commercially available solid fuel burner packages.
An additional objective of the present invention is to provide a system and
method that
will remove produced solids from the system by converting the liquids to gas
phase and
removing solids from the gas phase. The solids are as result from the fuel and
the evaporated
water. The solids can be silicon base materials, calcium based material,
different type of salts
carried by the water etc.
Furthermore, it is another objective of the present invention to provide a
system and
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method that enhances thermal efficiency and minimizes the amount of energy
used to produce
the steam injected into the underground formation to recover heavy oil.
It is a further objective of the present invention to provide a system and
method that
minimizes the amount of greenhouse gases released out into the atmosphere.
A further purpose of the present invention to provide a system and method that
serve to
make EOR facilities, like SAGD, more environmentally friendly by using low -
quality fuel.
It is still a further objective of the present invention to provide a method
for steam
production for the extraction of heavy bitumen.
It is an object of the present invention to provide a method for producing
super-heated,
dry, solid- free steam.
It is still a further objective of the present invention to provide a method
that uses
discarded water, possibly mixed with oil, clay or silica sand from a SAGD
facility.
It is another objective of the present invention to provide a system for oil
recovery using
heat injection.
These and other objectives and advantages of the present invention will become
apparent
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from a reading of the attached specifications and appended claims.
SUMMARY OF THE INVENTION
The method and system of the present invention for steam production for
extraction of
heavy bitumen by injecting the steam to an underground formation or by using
it as part from an
above ground oil extraction facility includes the following steps: (1) mixing
a low quality fuel
containing heavy bitumen, solid hydrocarbons or carbon emulsions and oxidizing
gases like
oxygen, enriched air or air; (2) combusting the mixture under high pressure
and temperature
while transferring the liquid phase to a gas phase; (3) evaporating de-oil
produced water and
make-up water at distillation facility to produce distilled water and
concentrate brine; (4)
recovering heat from the combustion reaction 2 for generating high pressure
steam; (5)
separating the solids from the gas phase in a dry form; (6) mixing the gas
with liquid water,
possibly with lime or other alkaline materials for S02 removal, at saturated
temperature and
pressure in order to produce a saturated, clean wet steam and gas mixture,
while removing most
of the S02 and scrubbing any remaining solids from the gas; (7) Injecting the
produced steam
into underground formation for EOR (Enhanced Oil Recovery)
If a ZLD (Zero Liquid Discharge) process is preferable, then prior to step (5)
there an
additional step may be added (3A); solids rich water is injected to the flow
of the combustion
gases to generate steam and solid waste. The water contains high levels of
total dissolved and
suspended solids (like silica, calcium, magnesium, sodium, carbonate or
organics and the
gypsum generated from the scrubbing of the S02). This step should be fulfilled
before step 5,
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due to the fact that the solids carried with the water are separated from the
gas phase in a dry
form. Step 3A can be done in a pressurized rotary kiln, in a fluidized bed
type pressurized spray
dryer design where the low quality water slurry is sprayed into the flow of
the combusted gas or
by integrated water injection as part of the boiler.
If a pressurized boiler is used and a thermal distillation process (like Multi-
Effect
Distillation), then prior to step (7) there an additional steps may be added;
(6A) Separating the
combustion NCG (Non Condensable Gases) from the steam by condensing the steam.
(6B)
Recovering the condensed water and condensed heat from the gas-steam mixture.
(6C) Using the
condensed water, possibly with the distilled water for generating the steam in
step 4. Steps 1-4
can be done using commercially - available solid fuel boiler packages and
distillation units.
The discharged NCG is at a relatively low temperature, close to the water
condensation
temperature. The cooled combustion gases can be discharged to the atmosphere.
An additional
option, if the recovery of C02 for sequestration is required, is to separate
the C02 from
combustion gases using a membrane. Low temperature membrane technology is
commercially
available. The discharged pressure will be used for the separation process.
Another option is to use an oxygen plant where the combustion gases will be
mainly C02
that can be directly recovered for sequestration.
According to one aspect of the present invention, there is provided a method
for
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producing a steam and gas mixture for injection into an underground formation
to extract heavy
bitumen comprising mixing fuel with oxidation gases to form a mixture;
combusting the mixture
under high pressures and temperatures to generate combustion gases; mixing
said combustion
gases with water having a high level of solids therein to form a combustion
gas mixture;
evaporating the water in the combustion gas mixture to leave the solids in a
dry form; washing
the combustion gas mixture with water at a saturated temperature and pressure;
scrubbing any
remaining solids from the combustion gas mixture to form a clean steam and gas
mixture; and
injecting the clean steam and gas mixture into the underground formation to
extract the heavy
bitumen.
According to another aspect of the present invention, there is provided a
system for producing a
clean steam and gas mixture for injection into an underground formation to
extract heavy
bitumen comprising mixing fuel with oxidation gases in a combustion boiler to
form a mixture;
combusting the mixture under high pressures and temperatures in the combustion
boiler to
generate combustion gases; mixing said combustion gases with water in the
combustion boiler
having a high level of solids therein to form a combustion gas mixture;
evaporating the water in
the combustion gas mixture to leave the solids in a dry form; transferring the
combustion gases
to a gas-solid separator unit; removing the dry form solids from the a gas-
solid separator unit;
transferring the combustion gases to a steam generation and wash vessel;
washing the
combustion gas mixture in the steam generation and wash vessel with water at a
saturated
temperature and pressure; scrubbing any remaining solids from the combustion
gas mixture to
form the clean steam and gas mixture; and injecting the clean steam and gas
mixture into the
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underground formation to extract the heavy bitumen.
According to another aspect of the present invention, there is provided a
method
for producing a pure steam mixture for injection into an underground formation
to extract
heavy bitumen comprising mixing fuel with oxidation gases to form a mixture;
combusting
the mixture under high pressures and temperatures to generate combustion
gases; mixing
said combustion gases with water having a high level of solids therein to form
a combustion
gas mixture; evaporating the water in the combustion gas mixture to leave the
solids in a
dry form; removing the dry form solids; washing the combustion gas mixture
with water at
a saturated temperature and pressure; scrubbing any remaining solids from the
combustion gas mixture to form the clean steam and gas mixture; transferring
the clean
steam and gas mixture to a heat exchange condenser, heat from the clean steam
and gas
mixture being used to heat water supplied from a distillation facility, the
water from the
distillation facility being combusted to generate a pure steam mixture that
can be used to
extract the heavy bitumen; and injecting the pure steam mixture into the
underground
formation to extract the heavy bitumen.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a schematic view of an illustration of the current invention for
an integrated solid
fuel boiler and distillation for EOR;
FIGURE 2 is a schematic view of an illustration of a boiler, solid removal,
wet steam scrubber
and integrated distillation unit for the production of steam for heavy oil
recovery;
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FIGURE 3 is a schematic view of an illustration of a boiler, direct contact
steam generator with
dry solid generation, solid removal, direct-contact scrubber with wet steam
generator, direct-
contact condenser and low - pressure steam generation and distillation
facility for generating
distilled water for steam generation during EOR;
FIGURE 3A is a schematic view of an illustration of an atmospheric boiler,
direct contact drier
with dry solid generation, solid removal, direct-contact scrubber with wet
steam generator, and
Mechanical Vapor Compression distillation facility for generating distilled
water for steam
generation in the boiler for EOR;
FIGURE 4 is a schematic view of: a direct contact steam generator, solids
separator, heat
exchanger for steam generation, scrubbing vessel and condenser for generating
low pressure
steam for distillation facilities;
FIGURE 5 shows an illustration of: a boiler, direct contact steam generator
with dry solid
generation, solid removal system, direct-contact scrubber with a wet steam
generator, direct-
contact condenser and a low pressure steam generation and distillation
facility for producing
distilled water for steam generation during EOR;
FIGURE 6 is a schematic view that shows one possible option, which makes use
of an MED
(Multi Effect Distillation) unit. This type of commercially available
distillation unit may be used
within the present invention; and
FIGURE 7 is a schematic view of the combustion side of the system described in
Fig. 6. with
water injected Pressurized Fluidized-Bed Boiler.
DETAILED DESCRIPTION OF THE DRAWINGS
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FIGURE 1 shows a block diagram. Boiler 1 combusts low quality fuel 4. For
example:
untreated, heavy crude oil, vacuum residue (VR), coal, asphaltin or petcoke in
slurry form, the
fuel is injected simultaneously with oxidation gas 5 (oxygen, air or enriched
air). Next, they are
combusted. The combustion boiler can be any boiler capable of combusting the
particular fuel.
Water 7 is used to generate high-pressure steam 6 for EOR. The discharged
combustion gases 8
are treated in block 2, where they are used to generate additional water
vapor, remove the S02
and the waste solids. This is done by injecting slurry water with the high
levels of solids into the
combustion gases that are discharged from the boiler. The amount of the
injected water is
controlled, so that all the injected water evaporates, leaving the solids it
carried in a dry form.
This can be done in a rotating kiln type unit used by different industries to
dry solids; or by an up
- flow high pressure drier, capable of eliminating the internal solids
deposits. The solids rich gas
further flows to a gas-solid separator unit. Such units are commercially
available and are capable
of removing most of the solids in a dry form. The removed solids are released
through the de-
compression hopper system, possibly with heat exchange to remove their heat
before they are
discharged. For dust control, the low quality water can be utilized by
spraying it onto the dry
powder. After most of the solids have been removed in a dry form 9, the solid,
lean gas flow 10
flows to liquid scrubber and steam generation vessel where the gas is washed
by water at a
saturated temperature. To remove the S02 the water can contain lime as well as
other alkali
materials. Removing heat separates the saturated gas from the steam; the water
is recovered in a
liquid form. For pressurized boiler the liquid water can be flashed to
generate low-pressure
steam. The condensation heat and steam are further used for distillation of
brackish and produced
water 13 in a commercially available distillation facility 3. The distillation
facility can be MED
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(Multi Effect Distillation) MSF (Multi-Stage Flash), or combined with VC
(Vapor Compression)
facilities. The distilled water 7 is used for generating steam 6 and is
injected to the oil formation
using injection well 16 for EOR. The brine produced by the distillation
facility 3 is recycled back
to generate steam and dry solids 2.
FIGURE 2 is a schematic view of one illustration of the present invention.
Fuel 2,
possibly with water 3 is mixed with oxidized gas 1 and injected into a
pressurized steam boiler 4
where the combustion is at an elevated pressure. The boiler can have solid
char discharged from
the bottom of its combustion chamber. The boiler produces high-pressure steam
5 from distilled
water feed 11. The steam is injected to the underground formation EOR.
Solids rich water 3 is injected to the combustion boiler 4. The amount of
water 3 is controlled to
make sure that all the water is converted to steam and that the remaining
solids are in a dry form.
The solid rich combustion gases discharged from the boiler flow to a dry
solids separator 7. The
dry solid separator is commercially available in a package. There are some gas-
solid separation
designs than can be used. The dry solids are removed in a dry form from the
separator 6. The
solids lean flow 8 is mixed with saturated water 14 in a direct contact steam
generation and wash
vessel 13 where the heat, carried with the gas 8 generates steam. Saturated
liquid water 16
washes the solids carried within the gas. The liquid water may include
alkaline materials (like
lime) to scrub the S02 present in the pressurized combustion gases generated
by the boiler.
Make-up water 15 is added to the scrubbing vessel 13 to replace the evaporated
water and the
solid rich water discharged from the vessel bottom. The solids rich water 3 is
discharged from
the bottom of vessel 13 and recycled back to the boiler 4 where the liquid
water is converted to
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steam and the solids are removed in a dry form, ready for disposal. The
combustion gases
saturated with wet steam 17 are free of solids. Also, most of the sulfuric gas
generated from
burning sulfur - rich fuels can be removed in the form of gypsum. The wet gas
mixture flows to
condenser and heat exchanger 18. Heat is removed from the combustion gases.
This results in
condensed steam that is separate from the combustion gases. The recovered heat
is used to
generate low-pressure steam 20 for operating distillation facility 25. The
saturated steam in the
combustion gas condenses 20 and it is used for steam generation. It also acts
as a heat source for
the distillation facility 25. The non - condensable combustion gas 19 is
carried out after most of
the condensed water vapor has been released from the vessel for further
treatment; For example,
into C02 recovery for sequestration or directly out into the environment (if
there is no
requirement for C02 sequestration).
The combustion gas condensates 11 together with the distilled water from the
distillation facility,
which is used as boiler - fed water 11 for generating the steam for EOR
injection. The distillation
facility continually generates brine water with high dissolved solids
concentration 21. The brine
water is recycled back to boiler 4, where the liquid water is converted to
steam and the dissolved
solids remain in a dry form. Some of the brine water can be used as make-up
water in the
scrubbing and steam-generating vessel 15.
The distillation unit 25 is a commercially available facility. There are a few
principles and
designs that can be used with it. For example, an MED (Multi Effect
Distillation system) can be
used. The distillation facility treats de-oiled produced water and make up
water. This could
potentially be brackish water from underground wells (not shown on the
sketch).
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FIGURE 3 is a schematic view of one embodiment of the present invention. Fuel
2,
possibly with water 3 is mixed with oxidize gas 1 and injected into steam
boiler 4. The boiler can
have a solid waste discharged from the bottom of the combustion chamber. The
boiler produces
high-pressure steam 5 from distilled feed water 19. The steam is injected to
the underground
formation through injection we116 for EOR.
The combustion gases with carry - on flying solids flow to direct contact
dryer 15. The dryer
generates steam from solid - rich water 14. The drier discharges a stream of
combustion gas 13
with dry steam and solid particles that were carried on from boiler 4 and from
the solid rich
water 14 that was used for steam generation. The amount of water 14 is
controlled to verify that
all the water is converted to steam and that the remaining solids are in a dry
form. The solid -
rich gas flow goes to a dry solids separator 16. The dry solid separator is
commercially available
package and it can be used in a variety of gas-solid separation designs. The
solids lean flow 12 is
mixed with saturated water 21 in direct contact steam generation and wash
vessel 20 where the
heat is carried in gas 12 generated steam. The solids carried with the gas are
washed by saturated
liquid water 23. The liquid water may include lime to scrub the S02 discharged
from the boiler,
generating additional solids. The solids rich water 24 is discharged from the
bottom of vesse120
and recycled back to drier 15 where the liquid water is converted to steam and
the solids are
removed in a dry form for disposal. The combustion gases, saturated with wet
steam 22 are
solids free and most of the sulfuric gases generated from burning sulfur -rich
fuel are removed in
the form of gypsum. The wet gas mixture flows to a direct contact heat
exchanger 25. Cold,
distilled, boiler - feed quality water 18 is continually sprayed into vessel
25, thus condensing
some of the steam that is part of the combustion gases. The steam operating
the distillation
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facility 29 supplied from the boiler 5. The saturated steam in the combustion
gas continually
condenses because of heat exchange with the cold distilled water 18. The non-
condensable
combustion gases 27 (after most of the water vapor was condensed) are released
from vessel 25
for further treatment, like C02 recovery for sequestration, or directly to the
environment, if there
is no requirement for C02 sequestration.
Distillation unit 11 produces distillation water 18. Some of it is used for
generating steam for
the distillation unit in vessel 25 and brine water 24. The brine water 24 is
recycled back to the
direct contact steam generator and solids drier 15 where the liquid water is
converted to steam
and the dissolved solids remain in a dry form.
Distillation unit 11 receives de-oiled produced water 9 that is separated in a
commercially
available separation facility that is currently in use by the industry.
Additional make-up water 34
is added. This water can be brackish water, from deep underground formation or
from any other
water source that is locally available to the oil producers. The quality of
the make-up water 34 is
suitable for the distillation facility 11, where there are typically very low
levels of organics due
to their tendency to damage the evaporator's performance or carry on and
damage the boiler.
Low quality water 35 with high levels of dissolved and suspended solids that
include organics is
not acceptable by distillation facility 11. It is sent to the direct contact
steam generator and solids
dryer 15, where the solids are separated in direct contact with the hot
combustion gas flow to two
components: gas and dry solids 13.
The cold distilled water produced by distillation facility 11 is used to
recover the steam and the
condensation heat in saturated gas flow 22. The condensate and the distilled
water 19 are sent for
the generation of high-pressure steam in boiler 4 and possibly also in a
separate steam generation
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facility 30 where high-pressure steam 32 is produced for EOR.
The brine 24 and the scrubbing water 21 are recycled back to 14 (to the direct
contact steam
generator and solid drier 15) as described before. Some brine 24 can be use in
the make-up water
34. The high - pressure steam from the boiler 5 and from a possibly separate
steam generator
facility 32 is injected to the injection well for EOR.
The we117 produces a mixture of tar, water and other contaminations. The oil
and the water are
separated in commercially available plants 10 to the de-oiled water 9 and to
the oil product 8.
FIGURE 3A is a schematic view of an illustration of an atmospheric boiler,
direct contact
drier with dry solid generation, solid removal, direct-contact scrubber with
wet steam generator,
and Mechanical Vapor Compression distillation facility for generating
distilled water for steam
generation in the boiler for EOR. Fuel 2, possibly with water is mixed with
air 1 and injected into
an atmospheric steam boiler 4. The boiler can have waste discharged from the
bottom of the
combustion chamber. The boiler produces high-pressure steam 3 from treated
distillate feed
water 5. The steam is injected to the underground formation through injection
we1121 for EOR.
The combustion gases with carry - on flying solids flow to direct contact
dryer 9. The dryer can
be commercially available direct-contact rotary drier or any other type of
direct contact drier
capable of generating solid waste and steam from solid - rich brine water 8.
The drier discharges
a stream of combustion gas 10 with dry steam and solid particles that were
carried on from boiler
4 and from the solid rich water 8. The amount of water 8 is controlled to
verify that all the water
is converted to steam and that the remaining solids are in a dry form. The
solid - rich gas flow
goes to a dry solids separator 12. The dry solid separator is commercially
available package and
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it can be used in a variety of gas-solid separation designs. The solids lean
flow 11 is mixed with
saturated water 22 in direct contact wash vessel 15. The solids carried with
the gas are washed by
saturated liquid water 22. The liquid water may include lime to scrub the S02
discharged from
the boiler, generating additional solids. The solids rich water 14 is
discharged from the bottom of
vessel 22 and recycled back to drier 9 where the liquid water is converted to
steam and the solids
are removed in a dry form for disposal. The combustion gases are solids free
and most of the
sulfuric gases generated from burning sulfur -rich fuel are removed in the
form of gypsum. The
combustion gases are released from vessel 15 for further treatment, like C02
recovery for
sequestration, or directly to the environment, if there is no requirement for
C02 sequestration.
Distillation unit 20 produces distillation water 8. . The brine water 24 is
recycled back to the
direct contact steam generator and solids drier 15 where the liquid water is
converted to steam
and the dissolved solids remain in a dry form.
Distillation unit 11 is a Mechanical Vapor Compression (MVC) distillation
facility. It receives
de-oiled produced water that is separated in a commercially available
separation facility that is
currently in use by the industry with additional make-up water 16. This water
can be brackish
water, from deep underground formation or from any other water source that is
locally available
to the oil producers. The quality of the make-up water is suitable for the
distillation facility 20,
where there are typically very low levels of organics due to their tendency to
damage the
evaporator's performance or carry on and damage the boiler. The distilled
water produced by
distillation facility 11 is treated by distillate treatment unit 17, typically
supplied as part of the
MVC distillation package. The treated distilled water 5 can be used in the
boiler to produce
100% quality steam for EOR.
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The brine 8 and the scrubbing water 14 are recycled back to the direct contact
drier 9 as
described before. Some brine 8 can be use in the make-up water 13. The high -
pressure steam
from the boiler 4 is injected to the injection well 21 for EOR.
FIGURE 4 is a schematic view of one embodiment of the invention. Fuel 2,
possibly with
water 3 is mixed with oxidizing gas 1 possibly with recycled cooled combustion
gas 11 and is
injected into a pressurized, direct - contact rotating steam generator 4 where
the combustion is at
elevated pressure. This produces high-pressure combustion gases and steam 13.
Solids - rich
water 12 is injected to the direct contact steam generator 4 where the water
evaporates to steam
and the solids are carried on with gas flow 13. The amount of water 3 is
controlled to verify that
all the water is converted to steam and that the remaining solids are in a dry
form and at the
desired temperature. The solid - rich combustion gases discharged from the
steam generator
flow to a dry solids separator 5. The dry solid separator is commercially
available package. The
dry solids are removed in a dry form from the separator 15. The solids lean
flow 14 goes through
heat exchanger 6 where high-pressure steam 27 is generated from distilled
water 17. Some of the
distilled water 28 can be used to generate steam in separate steam generation
facilities. If the
oxidized gas is comprised of oxygen or oxygen enriched air, some of the
combustion gases can
be recycled back to the direct contact steam generator 4 and mixed with the
oxidizing gas to
control the combustion temperature. The steam - rich combustion gases are
mixed with saturated
water in direct - contact steam generation and wash vessel 7 where the heat
carried by the gas 32
generates steam and the solids carried with the gas are washed by the
saturated liquid water 16.
The liquid water may include alkali materials, like lime, to scrub the S02
presence in the
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pressurized combustion gases generated by the steam generator 4. Make-up water
33 is added to
scrubbing vessel 7 to replace the evaporated water and the solid - rich water
discharged and
recycled from the vessel bottom 16. The combustion gases, saturated with wet
steam 19 are
solids - free and most of the sulfuric gas generated from burning sulfur rich -
fuel is removed in
the form of gypsum. The wet gas mixture 19 flows to heat exchange condenser 8
where the
thermal energy is used to heat the produced and make-up water 21, used by the
distillation
facility 30. The distillation facility 30 is also a commercially available
facility. For example, it
could be a Multi Effect Distillation unit. The condensed water 23 from
condenser 8 flows to a
flash tank separator 10. Steam generated in flash tank 25 is used to operate
the distillation
facility. The distillation facility produces distillation water. The
distillation water 26 together
with the liquid water from the flash tank 10 is used for steam generation in
the direct - contact
steam generator. Brine water 29 rejected from distillation facility 30 is
recycled, together with
the solid - rich water discharged from vessel 12, back to the direct contact
steam generator 4,
where the water converted to steam and the solids were removed in a dry form.
The non-
condensable combustion gases are released from heat exchanger 31. The C02 can
be recovered
and used for sequestration or released to the environment if there is no
requirement for the C02
recovery.
FIGURE 5 is a schematic view of one embodiment of the invention. Fue12,
possibly with
water 3 is mixed with oxidizing gas 1 and injected into a pressurized steam
boiler 5 where the
combustion is at elevated pressure, in the range of 2bar to 70bar. The boiler
can have a solid
char discharged from the bottom of the combustion chamber. The boiler produces
high - pressure
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steam 12 from distilled feed water 15. The steam is injected to the
underground formation
through injection we1149, for EOR.
The combustion gases with carry - on fly solids flow to a direct - contact
pressurized spray dryer
and steam generator 10. The dryer generates steam from solid - rich water 12.
The fluid
discharged from the drier contains fly solids that are generated from the
evaporated water as well
as solids that were carried within the combustion gas flow from the boiler.
The amount of water
12 is controlled to verify that all the water is converted to steam and that
the remaining solids are
in a dry form. As a result, the discharge from drier 10 is a dry combustion
gas mixture (i.e.- it has
super-heated dry steam). The solid - rich gas flows to a dry solids-gas
separator 8. The separator
is a commercially available package and it can be used with a variety of gas-
solid separation
designs. Dry solids are recovered for disposal through pressure reduction
chambers (not shown).
The solids lean flow 12 is mixed with saturated water 19 in direct - contact
steam generation and
wet scrubbing vessel 17, where the heat carried by the gas 13 generates steam.
The solids
carried by the gas are washed by the saturated liquid water 19. The liquid
water may include
alkali material, like lime, to scrub the S02 discharged from the boiler. The
solid - rich water 18
is discharged from the bottom of vessel 17 and recycled 12 back to drier 10,
where the liquid
water is converted to steam and where the solids are removed in a dry form for
disposal. The
combustion gases, saturated with wet steam 20 are solid - free and most of the
sulfuric gas
generated from burning sulfur - rich fuel is removed in the form of gypsum.
The wet gas mixture
flows to a direct contact heat exchanger and also to a steam condenser 36.
Cold, distilled, boiler
feed - quality water 30 is continually sprayed into vesse136 while condensing
some of the steam
that is part of the combustion gases. The amount and temperature of the liquid
injected water 30
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is controlled to maintain the heated condensing of liquid water 28 at a
temperature close to (but
not colder than) the saturated temperature of the partial steam pressure in
the vessel. The
saturated steam in combustion gas 20 continually condenses, because of its
heat exchange with
the cold distilled water 30 and increased quantities of the saturated liquid
water 28. The non-
condensable combustion gases 53 are released from vessel 36 for further
environmental - related
processing. This occurs after most of the water vapor is recovered and
condensed. Processing
may include C02 recovery for sequestration. Otherwise, the waste products can
be released
directly into the environment, if there are no laws stating otherwise, or if
there are no economic
advantages to C02 sequestration. There are few developed technologies that
separate C02 from
the pressurized discharged flow 53 that are able to use the discharged
pressure for reduction of
energy consumption during separation while still pressurizing and drying the
C02. If oxygen is
used as the oxidizer gas, some cooled combustion gases 27 (mainly C02 and H20)
will be
recycled back and mixed with the oxygen to maintain combustion temperatures at
a usable
range, typically less than 2000C. The technology for Oxy-combustion is well
known; boilers
designed for this process are commercially available.
The liquid water at saturated temperature 28 is delivered to flash tank 26 and
flashed at a
pressure lower then the partial pressure of the steam in vessel 36. It is
converted to pure steam 39
that is used to drive the distillation process 40. The condensation 29 from
flash tank 26 is
recycled back and used for generating steam in boiler 5, or in a separate
steam generator unit 43
for EOR. Distillation unit 40 is a commercially available unit. A typical
distillation technology
can be the Multi Effect Distillation unit, possibly with Thermal Vapor
Compression that uses
steam jet compressor 38 to increase system output by working as a heat pump
over the multi
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evaporator condensers cells, between line 32 and 33 (not shown). The
distillation produces BFW
(Boiler Feed Water) quality water 30 used for steam generation in boiler 5.
The distillation
facility produces brine water 23 with a high concentration of dissolved
solids. The brine water 23
is recycled back to the direct contact steam generator and solids drier 10
where the liquid water
is sprayed into the combustion gas and converted to steam and dry solids
particles.
Production well 51 produces a mixture of bitumen, water and gas 48. The
produced mixture is
separated in commercially available treatment plants that use a variety of
separation technologies
to separate the produced emulsion into oil products and water. The produced
hydrocarbons 47
are sold or sent for further treatment. The produced water is treated to
remove carbon
contaminants in commercially available processes 42. The de-oiled water 24 is
used as the water
source for distillation facility 40 and also possibly as make-up water for wet
scrubbing and steam
generation unit 17. Any oily water 25 is recycled back to drier 10 or used
with the fuel 3 for
preparing the solid fuel and water slurry 2 for the boiler 5. Additional make-
up water 45 possibly
brackish can be produced from a deep underground well 50. This water is added
to the produced
water and treated by distillation facility 40 or used as make-up water for the
wet scrubber and
steam generator 17. If an additional steam generator facility is used, like Co-
Gen or OTSG where
about 80%-90% quality steam is produced, then the steam is separated where
100% quality
steam 44 is injected through injection well 49 for EOR. The blow-down water 46
is recycled
back to the saturated water steam generator and wet scrubber 17.
Distillation unit 11 receives de-oiled, produced water 9 that is separated in
commercially
available separation facilities that are currently used by the industry.
Additional make-up water
45 is added. This water can be brackish water from deep underground
formations, 50 or from
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other water sources that are locally available to the oil producers. The
quality of the make-up
water 45 is suitable for the distillation facility 40, where, typically the
levels of organics are at
very low levels, due to their tendency to damage the evaporator's performance
or carry - on and
damage the boiler. Low quality water, 35 with high levels of dissolved and
suspended solids that
include organics are not accepted by the distillation facility 40. They are
sent to the direct contact
steam generator within solids dryer 10, where they are converted in direct
contact with the hot
combustion gas flow to steam and dry solids 11.
The cold distilled water produced by distillation facility 40 is used to
recover the condensed heat
in saturated gas flow 20, while generating low - pressure steam 39 for running
distillation facility
40. The rest of the condensation 29 and the distilled water 31 are combined
and sent for the
generation of high-pressure steam in boiler 5 and possibly, also in a separate
steam generation
facility 43 where high-pressure steam 12 is produced for EOR.
The brine 23 that is rejected from the distillation facility is recycled back
to dryer 10 and to
vessel 17, together with additional make-up water 4. The brine 23 and
scrubbing water 18 is
recycled back to 12, to the direct contact steam generator and solid drier 10,
as described before.
The high - pressure steam from boiler 5 and from a possibly separate steam
generator facility 43
is injected to the injection well 49 for EOR.
The produced well 51 produces a mixture of tar, water and other contaminants.
The oil and the
water is separated 41 to de-oiled water 24 and to oil product 47.
FIGURE 6 is a schematic view of integration with MED (Multi Effect
Distillation)
distillation system without Thermal Vapor Compression. Combustion gases 6 with
flying solids
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that were not removed by the dry solid-gas separation unit (shown on Figure
7), mixed with
saturated water 9 in direct contact steam generation and wet scrubbing vessel
7. In it, heat
carried by gas flow 6 generates steam and the solids carried by the gas are
washed by the
saturated liquid water 8. The liquid water may include alkali material like
lime to scrub the S02
discharged from the boiler. The solids rich water 9 is discharged from the
bottom of vessel 7 and
recycled back to the drier (shown on Figure 7), where the liquid water is
converted to steam and
the solids are removed in a dry form for disposal. The combustion gases
saturated with wet
steam 4 are solids free. Most of the sulfuric gas generated from burning
sulfur rich - fuel is
removed in the form of gypsum. The wet gas mixture 4 flows to a direct contact
steam condenser
heat exchanger 15. Cold, distilled, boiler feed quality water 3 is continually
sprayed into vessel
15, while heat and some of the steam that is part of the combustion gases is
recovered. The
amount and temperature of the liquid injected water 3 is controlled to
maintain the heated liquid
water 13 at a temperature close to (but not colder than) the saturated
temperature of the partial
steam pressure in the vessel. The saturated steam in combustion gas 4
continually condenses
because of heat exchange with the cold distilled water 3 and adding to the
distilled injected water
3. The non-condensable combustion gas 5 are released from vessel 15 for
further processing (like
C02 capturing) or released to the atmosphere, after most of the water vapor is
recovered and
condensed. The liquid water at saturated temperature 12 is delivered to flash
tank 16 and flashed
at a pressure lower than the steam partial pressure in vessel 15 to generate
pure steam 18 that is
used to drive the distillation process 30. The condensate 17 from flash tank
16 is recycled back
and used (possibly after some processing) as Boiler Feed Water for generating
steam for EOR.
The Multi Effect Distillation takes place in a series of vessels (effects) 23
and uses the principle
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of condensation and evaporation at reduced pressure. The heat is supplied to
the first effect 19 in
the form of steam 18. The steam 18 is injected to the first effect 19 at a
pressure range of 0.2-12
bar. The steam condenses while feed water 20 is heated. The condensation 21 is
collected and
used for boiler feed water 3 and for injection to vessel 15. Each effect
consists of a vessel 19, a
heat exchanger 21 and flow connections 20 and 24. There are several commercial
designs
available for the heat exchanger area, that have horizontal tubes with a
falling brine film or
vertical tubes with a rising liquids or a falling film or plates with a
falling film. The feed water
20 is distributed on the surface of the heat exchange and evaporator 21. The
steam produced in
each effect condenses on the colder heat transfer surface of the next effect.
The last effect 22
consists of the final condenser 22, continually cooled by the feed water, thus
preheating the feed
water 1. The feed water comprised from de-oiled produced water, brackish water
26 wells 25 or
ant other locally available water source. The brine concentrate 2 flows back,
where it is sprayed
and mixed with combustion gases generated by the boiler. All this is occurs
while steam and dry
solids are generated (shown on Figure 7).
FIGURE 7 is a schematic view of the combustion side of the system described in
Fig. 6.
Fuel 2 is mixed with air 55 and injected into a Pressurized Fluidized-Bed
Boiler 51 with water
injection. The boiler produces high-pressure steam 59 from distilled feed
water 3. The steam is
injected to the underground formation through injection well 73 for EOR.
The discharged NCG 5 expands to an atmospheric pressure 75 while compressing
the
combustion air 74 to the boiler combustion pressure 55. The C02 can be
separated from the
NCG using commercially available technologies. The combustion air injected at
the bottom of
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the boiler to maintain the fluidized bed. High pressure 100% quality steam 59
is generated from
distilled water 3 through heat exchange inside the boiler 56.
Hydrocarbons and water mixture 70 is produced from the production well 72. The
mixture is
separate in separation facility 68 where the heavy oil product, possibly mixed
with diluent 71, is
separate from the water. The produced water 69 is treated by de-oiled unit 67
where de-oiled
produced water 1 generated and sent to the MED unit (see Fig. 6). The produced
water that
contain organics 62 together with the concentrated brine from the distillation
facility 2 flows
back to the boiler 52, where it is sprayed at the upper section of the boiler
53 and mixed with the
up-flowing combustion gases generated by the boiler. The liquids evaporate
while steam and dry
solids are generated. Small solid particles carried with the up-flowing gas
and large solid
particles are falling to the fluidized bed by gravitation. The solid - rich
combustion gases
discharged from the boiler 61 flows to a dry solids separator 60. The dry
solid separator is
commercially available package. The dry solids are removed in a dry form from
the separator 63
through heat recover 64 and de-compression 65 sections. The solids lean flow 6
flows to vessel 7
(see Fig. 6).
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