U.S. patent application number 14/510548 was filed with the patent office on 2015-04-09 for indirect boiling for water treatment.
The applicant listed for this patent is CONOCOPHILLIPS COMPANY. Invention is credited to Kening GONG, David W. LARKIN, Peter N. SLATER.
Application Number | 20150096754 14/510548 |
Document ID | / |
Family ID | 52776047 |
Filed Date | 2015-04-09 |
United States Patent
Application |
20150096754 |
Kind Code |
A1 |
LARKIN; David W. ; et
al. |
April 9, 2015 |
INDIRECT BOILING FOR WATER TREATMENT
Abstract
Systems and methods relate to vaporizing water into steam, which
may be utilized in applications such as bitumen production. Initial
indirect vaporization of the water at a first pressure for
treatment precedes a steam generator boiling the water at a second
pressure higher than the first pressure. The indirect vaporization
of the water occurs in a vessel upon contact of the water with a
substance such as solid particulate heated to a temperature
sufficient to vaporize the water. Impurities in the water deposit
on the solid particulate and/or combust limiting pass through of
the impurities to the steam generator given that a vapor output of
the vessel from the initial indirect vaporization condenses and is
pressurized before being supplied to the steam generator.
Inventors: |
LARKIN; David W.;
(Bartlesville, OK) ; SLATER; Peter N.;
(Bartlesville, OK) ; GONG; Kening; (Bartlesville,
OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CONOCOPHILLIPS COMPANY |
Houston |
TX |
US |
|
|
Family ID: |
52776047 |
Appl. No.: |
14/510548 |
Filed: |
October 9, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61888576 |
Oct 9, 2013 |
|
|
|
Current U.S.
Class: |
166/303 ; 122/28;
166/57 |
Current CPC
Class: |
F22D 11/006 20130101;
E21B 43/2406 20130101; E21B 43/24 20130101; F22B 33/14
20130101 |
Class at
Publication: |
166/303 ; 122/28;
166/57 |
International
Class: |
F22B 1/04 20060101
F22B001/04; E21B 43/24 20060101 E21B043/24 |
Claims
1. A method of treating and vaporizing water, comprising:
circulating a solid particulate in a vessel; heating the solid
particulate; treating the water by contacting the water with the
solid particulate heated to a temperature for vaporizing the water
into steam that is at a first pressure and is then separated from
the solid particulate and condensed into a liquid to form a treated
feed; and vaporizing the treated feed to generate steam at a second
pressure higher than the first pressure.
2. The method according to claim 1, wherein the heating the solid
particulate is by combusting fuel inside the vessel.
3. The method according to claim 1, wherein the first pressure is
less than 1000 kilopascals.
4. The method according to claim 1, wherein the first pressure is
less than 5000 kilopascals and the second pressure is at least 6500
kilopascals.
5. The method according to claim 1, wherein the heating includes
supplying oxygen to the vessel to burn off organics from the water
that are deposited on the solid particulate.
6. The method according to claim 1, wherein the water contacts the
solid particulate in a riser such that the vaporizing provides lift
for transporting the solid particulate up the riser for gravity
return to the vessel.
7. The method according to claim 1, wherein the solid particulate
includes at least one of geldart A solids and geldart B solids.
8. The method according to claim 1, further comprising injecting
the steam at the second pressure into a formation and producing
steam condensate separated from recovered hydrocarbons to form the
water that is contacted with the solid particulate.
9. The method according to claim 1, wherein the water that is
contacted with the solid particulate comes from blown-down liquid
waste produced during steam generation.
10. The method according to claim 1, further comprising separating
combustion gases used in heating the solid particulate from the
treated feed.
11. The method according to claim 1, wherein combustion gases used
in heating the solid particulate are exhausted without mixing with
the steam produced by the water contacting the solid
particulate.
12. A system for treating and vaporizing water, comprising: a
vessel with a fluidized bed of circulating solid particulate; a
heat source to transfer thermal energy to the solid particulate; an
inlet for the water into the vessel to contact the water with the
solid particulate heated to a temperature for vaporizing the water
into steam that is at a first pressure; an outlet of the vessel in
which the steam flows separated from the solid particulate; a
cooler coupled to the outlet to condense the steam into a liquid
providing a treated feed; and a steam generator to vaporize the
treated feed and output resulting steam at a second pressure higher
than the first pressure.
13. The system according to claim 12, wherein the heat source
includes a fuel and oxidant supply coupled to the vessel for
heating the solid particulate by combustion.
14. The system according to claim 12, wherein the first pressure is
less than 1000 kilopascals.
15. The system according to claim 12, wherein the first pressure is
less than 5000 kilopascals and the second pressure is at least 6500
kilopascals.
16. The system according to claim 12, further comprising a riser in
which the water contacts the solid particulate such that the
vaporizing provides lift for transporting the solid particulate up
the riser for gravity return to the vessel.
17. The system according to claim 12, wherein the solid particulate
includes at least one of geldart A solids and geldart B solids.
18. The system according to claim 12, further comprising: an
injection well coupled to the steam generator for introducing the
steam at the second pressure into a formation; and a production
well coupled to a separator that removes steam condensate from
recovered hydrocarbons to provide the water that is contacted with
the solid particulate.
19. The system according to claim 12, further comprising a
separator for removing combustion gases used in heating the solid
particulate from the treated feed.
20. The system according to claim 12, further comprising an exhaust
from the vessel for removing combustion gases used in heating the
solid particulate without mixing of the gases with the steam
produced by the water contacting the solid particulate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a non-provisional application which
claims benefit under 35 USC .sctn.119(e) of and priority to U.S.
Provisional Application Ser. No. 61/888,576 filed 9 Oct. 2013,
entitled "INDIRECT BOILING FOR WATER TREATMENT," which is
incorporated by reference herein in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] None.
FIELD OF THE INVENTION
[0003] Embodiments of the invention relate to methods and systems
for generating steam which may be utilized in applications such as
bitumen production.
BACKGROUND OF THE INVENTION
[0004] Several techniques utilized to recover hydrocarbons in the
form of bitumen from oil sands rely on generated steam to heat and
lower viscosity of the hydrocarbons when the steam is injected into
the oil sands. One common approach for this type of recovery
includes steam assisted gravity drainage (SAGD). The hydrocarbons
once heated become mobile enough for production along with the
condensed steam, which is then recovered and recycled.
[0005] Costs associated with building a complex, large,
sophisticated facility to process water and generate steam
contributes to economic challenges of oil sands production
operations. Such a facility represents much of the capital costs of
these operations. Chemical and energy usage of the facility also
contribute to operating costs.
[0006] Past approaches rely on once through steam generators
(OTSGs) to produce the steam. However, boiler feed water to these
steam generators requires expensive de-oiling and treatment to
limit boiler fouling problems. Even with this treatment, fouling
issues persist and are primarily dealt with through regular pigging
of the boilers. This recurring maintenance further increases
operating costs and results in a loss of steam production capacity,
which translates to an equivalent reduction in bitumen
extraction.
[0007] Therefore, a need exists for methods and systems for
generating steam that enable efficient hydrocarbon recovery from a
formation.
BRIEF SUMMARY OF THE DISCLOSURE
[0008] In one embodiment, a method of treating and vaporizing water
includes circulating a solid particulate in a vessel and heating
the solid particulate. Treating the water includes contacting the
water with the solid particulate heated to a temperature for
vaporizing the water into steam, which is at a first pressure and
is then separated from the solid particulate and condensed into a
liquid to form a treated feed. The method further includes
vaporizing the treated feed to generate steam at a second pressure
higher than the first pressure.
[0009] For one embodiment, a system for treating and vaporizing
water includes a vessel with a fluidized bed of circulating solid
particulate, a heat source to transfer thermal energy to the solid
particulate, an inlet for the water into the vessel to contact the
water with the solid particulate heated to a temperature for
vaporizing the water into steam that is at a first pressure, and an
outlet of the vessel in which the steam flows separated from the
solid particulate. A cooler couples to the outlet to condense the
steam into a liquid providing a treated feed. A steam generator
vaporizes the treated feed and outputs resulting steam at a second
pressure higher than the first pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A more complete understanding of the present invention and
benefits thereof may be acquired by referring to the following
description taken in conjunction with the accompanying
drawings.
[0011] FIG. 1 is a schematic of a system including a fluidized bed
for initial vaporization to treat water fed into a steam generator
operated at injection pressure, according to one embodiment of the
invention.
[0012] FIG. 2 is a schematic of an exemplary system with input into
a riser for the initial vaporization to treat the water, according
to one embodiment of the invention.
DETAILED DESCRIPTION
[0013] Turning now to the detailed description of the preferred
arrangement or arrangements of the present invention, it should be
understood that the inventive features and concepts may be
manifested in other arrangements and that the scope of the
invention is not limited to the embodiments described or
illustrated.
[0014] Embodiments of the invention relate to systems and methods
for vaporizing water into steam, which may be utilized in
applications such as bitumen production. Initial indirect
vaporization of the water at a first pressure for treatment
precedes a steam generator boiling the water at a second pressure
higher than the first pressure. The indirect vaporization of the
water occurs in a vessel upon contact of the water with a substance
such as solid particulate heated to a temperature sufficient to
vaporize the water. Impurities in the water deposit on the solid
particulate and/or combust limiting pass through of the impurities
to the steam generator given that a vapor output of the vessel from
the initial indirect vaporization condenses and is pressurized
before being supplied to the steam generator.
[0015] FIG. 1 illustrates a system for recovering hydrocarbons that
includes at least one production well 100 and at least one
injection well 102. In an exemplary embodiment, the injection well
102 and the production well 100 provide a well pair for a steam
assisted gravity drainage (SAGD) operation. Various other thermal
oil recovery operations including cyclic steam stimulation, solvent
aided SAGD and steam drive may also employ processes described
herein.
[0016] In operation, a steam chamber develops as steam is
introduced into a formation through the injection well 102 and a
resulting petroleum fluid of steam condensate and the hydrocarbons
migrates through the formation due to gravity for recovery with the
production well 100. The steam comes from water treated as
described herein using a vessel 104 and supplied to a steam
generator 106. The steam contacts the hydrocarbons such that heat
transfers upon condensation making the hydrocarbons mobile and
enabling gravity drainage thereof.
[0017] For some embodiments, the water recycled and treated for
steam generation may come from blown-down liquid waste produced
during steam generation and/or from separated production fluid
associated with the SAGD bitumen recovery operation. A production
separator 108 thus receives the production fluid to remove the
hydrocarbons from the water. The water output from the production
separator 108 passes to the vessel 104.
[0018] The water at time of being vaporized in the vessel 104 for
treatment may still contain: at least about 1000 parts per million
(ppm), at least 10,000 ppm or at least 45,000 ppm total dissolved
solids; at least 100 ppm, at least 500 ppm, at least 1000 ppm or at
least 15,000 ppm organic compounds or organics; and at least 1000
ppm free oil. This initial vaporization and then condensation may
provide the only treatment of the water relied on preceding steam
generation for injection and may feed to a steam generator 106
water containing less than 1000 ppm or less than 100 ppm total
dissolved solids; less than 100 ppm or less than 50 ppm organic
compounds or organics; and less than 1000 ppm or less than 100 ppm
free oil.
[0019] The vessel 104 contains solid particulate. As used herein,
examples of the solid particulate include geldart A solids, geldart
B solids or any mixture thereof. Exemplary geldart A or B solids
include sand, metal spheres, cracking catalyst and mixtures
thereof. In some embodiments, fluidization of the solid particulate
keeps the solid particulate moving within the vessel 104 during
operation to vaporize the water. Such fluidization may involve
circulation of the solid particulate and may rely on addition of
supplemental steam.
[0020] The vessel 104 further couples to a heat source that may
include a supply of oxidant, such as air or oxygen, and fuel, such
as natural gas or methane. The oxygen and fuel introduced into the
vessel 104 combusts to heat the solid particulate such that the
water introduced into the vessel 104 vaporizes upon contact with
the solid particulate. During such combustion, contaminants, such
as organic compounds deposited on the solid particulate from the
water, may partially or fully convert into carbon dioxide and
water, and some salts deposited on the solid particulate from the
water may come off and be swept out of the vessel 104.
[0021] Surface area of the solid particulate provides enough
dispersion of the deposits to limit heat transfer interference. As
needed over time, replacing some or part of the solid particulate
may ensure desired performance is maintained at minimal cost and
with limited to no interruption. For example, a lockhopper system
employed with embodiments can enable such withdrawal and
replacement while in continuous operation.
[0022] The vessel 104 operates at a pressure between atmospheric
pressure and less than a desired injection pressure of the steam
into the injection well 102. These pressures limit compression
needs with respect to the fuel and oxidant supplied to the vessel
104. In some embodiments, the pressure in the vessel 104 ranges
between 0 and 350 kilopascals (kPa), 0 and 700 kPa, 0 and 5000 kPa
or less than 1000 kPa. A gaseous outlet 112 of the vessel 104 thus
conveys water vapor at a corresponding pressure mixed with
combustion exhaust. The water vapor exits the vessel 104 through
the gaseous outlet 112 while the solid particulate remains in the
vessel 104 and/or is trapped by filters or cyclones, for
example.
[0023] A condenser or heat exchanger 114 couples to the gaseous
outlet 112 of the vessel 104 and cools the water vapor into a
liquid. A treatment separator 116 receives flow from the heat
exchanger 114 for removal of gases, such as the combustion exhaust,
from the water that a pump 118 then pressurizes for feeding to the
steam generator 106. The pump 118 may pressurize the water to above
6500 kPa such that the steam conveyed to the injection well 102 is
at the desired injection pressure. For efficiency, heat exchange
may preheat the water from the treatment separator 116 prior to
being supplied to the steam generator 106.
[0024] An example of the steam generator 106 includes an economical
and efficient package drum boiler, which has stringent feed
impurity limits that may not be practical to achieve with prior
water treatment options. Other types of the steam generator 106
suitable for use include a once through steam generator or direct
steam generator. Regardless of operational configuration of the
steam generator 106, limiting the feed impurities with use of the
vessel 104 for water treatment can reduce fouling issues and
blown-down waste liquid.
[0025] In some embodiments, the drum boilers used for the steam
generator 106 enable locating the steam generator 106 at a remote
well pad or within 100 meters of the injection well 102. Large
scale and complex steam generation approaches depend on producing
the steam at a central processing facility. However, heat loss in
steam delivery lines from the central processing facility to the
remote well pad limits length of such lines.
[0026] Various options exist for adding makeup water if necessary.
In some embodiments, additional water 110, such as saline source
water, combines with the water from the production separator 108.
For some embodiments, the additional water 110 may first be treated
by reverse osmosis, for example, and heated to provide steam, which
is at a pressure corresponding to the pressure of the water being
supplied to the vessel 104 and in which the steam is combined for
preheating thereof. Such preheating of the water to the vessel 104
may enable limiting capital costs associated with the vessel
104.
[0027] The makeup water may further bypass the vessel 104. In some
embodiments, flow from the steam generator 106 combines with
another steam source 120 at a corresponding pressure for
introduction of the steam into the injection well 102. For example,
saline source water may pass through treatment, such as reverse
osmosis, and then be pressurized and boil to provide the steam
source 120.
[0028] FIG. 2 shows an alternative system with input of water into
a riser 205 forming part of a heating vessel 204 for the initial
vaporization to treat the water that is recovered from a production
well 200 and removed from oil with a production separator 208.
Solid particulate circulates through the riser 205 and the heating
vessel 204. Similar to the system in FIG. 1, reactants for
combustion enter the heating vessel 204 and are ignited in order to
regain thermal energy used to vaporize the water.
[0029] Flue gases from the combustion exit the heating vessel 204
through an exhaust following any filtering to retain the solid
particulate. Light gases that can dissolve in the water thereby
separate out. Limiting conveyance of these gases with the vaporized
water may facilitate controlling acidity of the water and may not
rely on downstream separation following condensing of the vaporized
water.
[0030] The solid particulate heated in the heating vessel 204
transfers to the riser 205 where the water contacts the solid
particulate resulting in vaporizing the water. The vaporized water
provides lift for the solid particulate in the riser 205. The solid
particulate once up the riser 205 then settles and returns by
gravity to the heating vessel 204 since the heating vessel 204 is
disposed below a top of the riser 205. The vaporized water exits
the riser 205 at a gaseous outlet 212.
[0031] A heat exchanger 214 couples to the gaseous outlet 212 of
the riser 205 and cools the water vapor into a liquid. A pump 118
receives flow from the heat exchanger 214 and pressurizes the water
then supplied to a steam generator 206. The pump 218 may pressurize
the water to above 6500 kPa such that the steam from the steam
generator 206 conveyed to an injection well 102 is at the desired
injection pressure.
[0032] Configurations to provide for the indirect vaporization of
the water in order to treat the water may employ further attributes
as described in the following patent applications: U.S. application
Ser. No. 13/547,565, entitled "Indirect Steam Generation System and
Process" filed Jul. 7, 2012; U.S. Application Ser. No. 61/737,973,
entitled "Heating for Indirect Boiling" filed Dec. 17, 2012; U.S.
Application Ser. No. 61/737,948, entitled "Water with Solvent
Indirect Boiling" filed Dec. 17, 2012; and U.S. Application Ser.
No. 61/737,967, entitled "Heat Exchange for Indirect Boiling" filed
Dec. 17, 2012. Each of the aforementioned patent applications is
hereby incorporated by reference in their entirety. In particular,
these patent applications describe indirect vaporization at the
injection pressure but may be applied as described herein to
vaporize and condense water for treatment while at pressures less
than the injection pressure with subsequent steam generation using
the water from such treatment at the injection pressure.
[0033] Although the systems and processes described herein have
been described in detail, it should be understood that various
changes, substitutions, and alterations can be made without
departing from the spirit and scope of the invention as defined by
the following claims. Those skilled in the art may be able to study
the preferred embodiments and identify other ways to practice the
invention that are not exactly as described herein. It is the
intent of the inventors that variations and equivalents of the
invention are within the scope of the claims, while the
description, abstract and drawings are not to be used to limit the
scope of the invention. Each and every claim below is hereby
incorporated into this detailed description or specification as
additional embodiments of the present invention. The invention is
specifically intended to be as broad as the claims below and their
equivalents.
* * * * *