U.S. patent application number 13/013232 was filed with the patent office on 2012-07-26 for online pigging system and method.
This patent application is currently assigned to TECHNIP FRANCE. Invention is credited to Peter Schroeer ARMSTRONG, Gregory Bryan CARGLE, Hans Christian DREYER, Amit GUPTA, Shawn Ashley WENTZ.
Application Number | 20120186781 13/013232 |
Document ID | / |
Family ID | 45768284 |
Filed Date | 2012-07-26 |
United States Patent
Application |
20120186781 |
Kind Code |
A1 |
DREYER; Hans Christian ; et
al. |
July 26, 2012 |
ONLINE PIGGING SYSTEM AND METHOD
Abstract
The disclosure provides a heat transfer system having a tubing
coil for heating fluid flowing therein, where the tubing coil can
be pigged (descaled) while operationally online, instead of
offline. The online system uses an assembly of valves and
associated equipment to connect to a pig launcher and pig receiver
while the system is online. A valve opens and the pig launches into
the flow stream under pressure through the valve and travels along
the tube with the fluid. The system continues to produce heated
fluid with the pig in the flow path. A pig receiver receives the
pig after the pigging, and then is isolated from the flow path of
the heated fluid by another valve. The pig launcher, pig receiver,
and pig are removed, and this process is repeated for any other
passes in the tubing coil.
Inventors: |
DREYER; Hans Christian;
(Sugar Land, TX) ; ARMSTRONG; Peter Schroeer;
(Katy, TX) ; CARGLE; Gregory Bryan; (Cypress,
TX) ; WENTZ; Shawn Ashley; (The Woodlands, TX)
; GUPTA; Amit; (Katy, TX) |
Assignee: |
TECHNIP FRANCE
Courbevoie
FR
|
Family ID: |
45768284 |
Appl. No.: |
13/013232 |
Filed: |
January 25, 2011 |
Current U.S.
Class: |
165/95 |
Current CPC
Class: |
F22B 29/06 20130101;
C10G 2300/805 20130101; F01K 23/10 20130101; F28G 1/12
20130101 |
Class at
Publication: |
165/95 |
International
Class: |
F28G 15/04 20060101
F28G015/04 |
Claims
1. A heat transfer system, comprising: a heat source coupled to a
chamber having a tubing coil disposed therein, the heat source
adapted to heat at least a portion of a fluid in the tubing coil
into a heated fluid by providing heat to the tubing coil, the
tubing coil having an inlet and an outlet, the inlet adapted to
receive the fluid for flowing through a flow path in the tubing
coil and the outlet adapted to allow the heated fluid to exit the
tubing coil; a first inlet connection coupled to the inlet for
coupling with a supply line to supply the fluid into the tubing
coil; a second inlet connection coupled to the inlet and fluidicly
independent of the first inlet connection; an inlet valve coupled
to the second inlet connection; a third inlet connection coupled to
the inlet valve; a pig launcher coupled to the third inlet
connection, the pig launcher adapted to launch a pig into the
tubing coil through the inlet valve; a first outlet connection
coupled to the outlet and adapted to allow the heated fluid to exit
therethrough; a second outlet connection coupled to the outlet and
fluidicly independent of the first outlet connection; an outlet
valve coupled to the second outlet connection; a third outlet
connection coupled to the outlet valve; and a pig receiver coupled
to the third outlet connection, the pig receiver adapted to receive
the pig from the tubing coil through the outlet valve.
2. The system of claim 1, wherein the heat transfer system
comprises a steam generator, the fluid in the tubing coil comprises
feedwater, and the heated fluid comprises steam.
3. The system of claims 2, wherein the steam generator comprises a
once-through steam generator, and the heat source comprises a
burner.
4. The system of claim 2, wherein the steam generator comprises a
once through heat recovery steam generator, and the heat source
comprises a gas turbine, a burner, or a combination thereof.
5. The system of claim 1, wherein the fluid comprises feedwater,
the heated fluid comprises steam, and further comprising; a steam
pipeline coupled to the outlet of the tubing coil and disposed in a
geologic stratum having hydrocarbons, the steam pipeline having an
injection portion with openings to allow the steam to be injected
into the geologic stratum; a collection pipeline disposed in the
geologic stratum and having a collection portion with openings to
allow heated hydrocarbons from the steam to flow into the
collection pipeline; and a processor adapted to process the heated
hydrocarbons after collection.
6. The system of claim 1, wherein one or more of the pig launcher,
inlet valve, and second inlet connection and third inlet connection
are longitudinally aligned with a longitudinal axis of the tubing
coil adjacent the inlet.
7. The system of claim 6, wherein the first inlet connection is
nonaligned with the longitudinal axis of the tubing coil adjacent
the inlet.
8. The system of claim 1, wherein one or more of the pig receiver,
outlet valve, and second outlet connection and third outlet
connection are longitudinally aligned with a longitudinal axis of
the tubing coil adjacent the outlet.
9. The system of claim 8, wherein the first outlet connection is
nonaligned with the longitudinal axis of the tubing coil adjacent
the outlet.
10. The system of claim 1, wherein the tubing coil comprises
multiple tubing passes, and wherein at least two of the tubing
passes each have an inlet and an outlet and an inlet valve coupled
to the inlet and an outlet valve coupled to the outlet for coupling
each of the at least two tubing passes to the pig launcher and the
pig receiver.
11. A method of pigging a heat transfer system, the system having a
heat source coupled to a chamber having a tubing coil disposed
therein, the tubing coil having one or more tubing passes, the heat
source adapted to heat at least a portion of the fluid in the
tubing coil into a heated fluid by providing heat to the tubing
coil, the tubing coil having an inlet and an outlet, the inlet
adapted to receive the fluid for flowing through a flow path in the
tubing coil, and the outlet adapted to allow the heated fluid to
exit the tubing coil, the heat transfer system further having: a
first inlet connection coupled to the inlet for coupling with a
supply line to supply the fluid into the tubing coil; an inlet
valve coupled to the inlet fluidicly independent of the first inlet
connection; a pig launcher coupled to the inlet valve, the pig
launcher adapted to launch a pig into the tubing coil through the
inlet valve; a first outlet connection coupled to the outlet and
adapted to allow the heated fluid to exit therethrough; an outlet
valve coupled to the outlet fluidicly independent of the first
outlet connection; and a pig receiver coupled to the outlet valve,
the pig receiver adapted to receive the pig from the tubing coil
through the outlet valve, the method comprising: maintaining
operation of the heat transfer system by continuing to supply fluid
through the first inlet connection into the tubing coil; opening
the inlet valve; launching the pig into a tubing pass of the tubing
coil through the inlet valve and into a flow path of the fluid;
descaling tubing surfaces of the tubing pass while continuing to
generate the heated fluid in the tubing pass; opening the outlet
valve; ejecting the pig through the outlet valve into the pig
receiver; and flowing the heated fluid generated upstream and
downstream of the pig in the tubing pass through the outlet
independent of the outlet valve.
12. The method of claim 11, further comprising closing the inlet
valve and the outlet valve and continuing to flow the fluid into
the inlet and the heated fluid out of the outlet.
13. The method of claim 11, wherein the tubing coil comprises
multiple tubing passes, and wherein at least two of the tubing
passes each have an inlet and an outlet and an inlet valve coupled
to the inlet and an outlet valve coupled to the outlet, and further
comprising removing the pig launcher and the pig receiver from a
first tubing pass and assembling the pig launcher and pig receiver
to an inlet valve and an outlet valve on a second tubing pass.
14. The method of claim 13, further comprising pigging the second
tubing pass while maintaining operation of the second tubing
pass.
15. The method of claim 11, wherein the fluid comprises feedwater,
the heated fluid comprises steam, and the outlet is coupled to a
steam pipeline disposed in a geologic stratum containing
hydrocarbons, and further comprising injecting the steam through
the steam pipeline into the geologic stratum to heat the
hydrocarbons and collecting at least a portion of the heated
hydrocarbon into a collection pipeline.
16. The method of claim 11, wherein the pig launcher is
longitudinally aligned with a longitudinal axis of the tubing coil
adjacent the inlet, and further comprising launching the pig from
the pig launcher in alignment with the longitudinal axis of the
tubing coil.
17. The method of claim 11, wherein the pig receiver is
longitudinally aligned with a longitudinal axis of the tubing coil
adjacent the outlet, and further comprising receiving the pig into
the pig receiver in alignment with the longitudinal axis of the
tubing coil.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO APPENDIX
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The disclosure relates generally to a method for cleaning
heat transfer systems, and more specifically, to heat transfer
systems having tubing coils for passing fluid therethrough to be
heated by a heat source.
[0006] 2. Description of the Related Art
[0007] Heat transfer systems having tubing coils are used in a
number of applications. A heat source transfers heat through a heat
exchanger generally having a chamber and a tubing coil therein. The
heat source heats the tubing coil that in turn heats a fluid
flowing through the tubing coil. The heat source can be, for
example, a fuel combustion burner, radiant heat source, including
infrared, hot fluids, including gases, or exhaust fluids from a
turbine or engine, or other waste heat fluids. FIG. 1 is a
representative schematic diagram of a fire heater for heating
hydrocarbon in a tubing coil. If the fluid is a hydrocarbon, the
hydrocarbon in the tubing coil can be heated to change viscosity to
improve flowability and handling. The system 100 can include a heat
source, such as a burner 102, that provides heat into a chamber 104
having a tubing coil 106. The tubing coil 106 has an inlet 108 and
an outlet 110 through which the hydrocarbon can flow in and out the
tubing coil. An exhaust 112 allows exhaust gases to exit the
chamber 104. If the temperature is sufficiently high, the
hydrocarbon fluid can undergo a process known as "cracking," when
the high-boiling, high-molecular weight hydrocarbon fractions of a
hydrocarbon fluid are converted into lighter weight, more valuable,
hydrocarbon fluids, such as gasoline and other products.
[0008] If the fluid is water, the water can be heated, for example,
into steam. An exemplary typical heat transfer system for water is
a once-through heat recovery steam generator ("OTHRSG"). FIG. 2 is
a representative schematic diagram of an OTHRSG system with a
tubing coil. The OTHRSG system 200 uses a heat exchanger, having a
chamber 204 with a tubing coil 206. The system 200 can include a
heat source 202, such as gas turbine exhaust or waste heat, to
transfer heat into water passing through the tubing coil 206 from
an inlet 208 to an outlet 210. An exhaust 212 allows exhaust gases
to exit the chamber 204. The resulting heated water, such as steam,
be used in various processes, including to drive a steam
turbine.
[0009] A specialized type of OTHRSG without boiler drums is known
as a once-through steam generator ("OTSG"). FIG. 3 is a
representative schematic diagram of an OTSG system. The OTSG system
300 includes a chamber 304 with a tubing coil 306 therein. The
system 300 can include a heat source 302, such as a burner, to
transfer heat into water passing through the tubing coil 306 from
an inlet 308 to an outlet 310. An exhaust 312 allows exhaust gases
to exit the chamber 304.
[0010] More specifically, OTSG systems can be used, for example, to
generate steam for oil sands for crude oil exploration, extraction,
production, and related markets, including Steam Assisted Gravity
Drainage (SAGD) projects. A representative OTSG system is shown in
FIGS. 4 and 5 for use with an oil sands production facility. FIG. 4
is a schematic perspective view of an OTSG facility for extraction
of hydrocarbon from oil sands. FIG. 5 is a schematic cross
sectional side view of the OTSG unit producing steam for extraction
of hydrocarbon from the oil sands. The figures will be described in
conjunction with each other.
[0011] An OTSG system 2 includes water tanks 4 with OTSG units 8
located in a building 6. An OTSG unit 8 includes a heat source 10,
such as a burner, that is used to generate heat inside a chamber 15
typically having a feedwater preheat zone 12 and a steam generation
zone 14. A supply line 13 provides feedwater to a tubing coil 16
through a tubing inlet 18. Heat is transferred from the heat source
to the feedwater in the tubing coil 16 to generate steam. The steam
exits a tubing outlet 20 of the tubing coil 16 into a steam
pipeline 22 that transports the steam into geological strata 24
having an oil sands layer 26 and injects the steam through openings
in the pipeline 22 in an injection zone 28. The process uses the
steam heat to heat the hydrocarbons in the sand to a flowable
consistency for extraction by flowing by gravity the hydrocarbons
in a collection zone 30 into a collection pipeline 32. The
collection pipeline flows the hydrocarbons into a processor unit 34
for extraction of the water from the hydrocarbons and other
processing.
[0012] The tubing coil 16 of an OTSG unit typically has multiple
tubing passes designed into its heat transfer system, and typically
four or six passes. Each pass is a serpentine-arranged single tube
with essentially one inlet 18, as a point of entry, and one outlet
20, as a point of exit, per pass. In addition to heating by
convection from hot gases, the tube is typically disposed along a
radiant wall in the OTSG unit to maximize heat transfer. For each
tubing pass, feedwater enters the inlet 18 for the tube and mostly
steam with some water (typically 80% steam and 20% saturated water)
exits through the outlet 20 of the tube.
[0013] However, feedwater impurities naturally build up in the
tubing coil 16 of the OTSG unit as the water is converted to steam.
The impurities cause scaling along the tube walls (known as "tube
fouling") which reduces heat transfer effectiveness and may
eventually lead to plugging of the tube. Over time, scaling
adversely impacts steam production and fuel consumption with
subsequent impact on unit operation and therefore oil production
from the oil sands.
[0014] Most oil producers employing OTSG technology utilize
multiple OTSG units mainly due to the scaling issue. The only
currently available technology for descaling OTSG units is a
process called "offline pigging."
[0015] Offline pigging requires taking the entire OTSG unit offline
from a multi-OTSG unit configuration. The individual OTSG unit 8 is
shut down and steam production is halted for that one unit. As the
individual OTSG unit is taken offline, equipment from other
portions of the OTSG unit that is connected to the inlet and outlet
of the tubing coil, and particularly the tubing pass, is
disconnected and removed. A pigging system is mounted to the inlet
and outlet of the tubing pass. The pigging system includes a pig
launcher, pig receiver, and a pig. The pig launcher is placed at
the inlet of tubing pass and pig receiver is placed at the outlet
of tubing pass. The pig is launched from the pig launcher into the
tubing pass under water pressure particular to the offline pigging
process. As the pig passes through the tubing pass, the pig removes
scales from the tubing inside surfaces. The pig exits the outlet
and is received by the pig receiver. Flush water follows the pig,
and scale is carried away with water out of the system. One pass is
pigged at a time. For units with multiple passes, each pass is
descaled in turn by disconnecting and removing the equipment from
the inlet and outlet of each pass, connecting a pigging system to
the inlet and outlet, launching and receiving the pig, and flushing
out the scale, then reconnecting. Once all the passes have been
descaled, the unit is then turned back on for normal operation.
This offline pigging practice is the current industry
convention.
[0016] The pigging process is repeated for each OTSG unit on a
rotation basis. It normally takes a few hours for an OTSG unit to
cool down for descaling, and a few more hours to resume full
capacity steam production once started up again to full operating
temperatures. Further, when the OTSG unit is used for the oil
sands, the production may be delayed for several days to even a
month or more, while the production envelope restabilizes the heat
and pressures underground. Thus, often a duplicate OTSG unit is
available to maintain the steam production, while the other OTSG
unit is offline for descaling. However, the additional OTSG unit
available for use when the other unit is offline is an intensive
capital expenditure with operating expenditures as well.
[0017] Further, the turning off and on of the OTSG unit in the
descaling process has a measurable impact on useful life on the
tube or tubes and related equipment due to thermal stresses from
transient conditions, thereby increasing maintenance with labor and
material replacement costs over the life of the system.
[0018] Thus, there remains a need for an improved system and method
for descaling an OTSG unit without having to force the OTSG unit
offline.
BRIEF SUMMARY OF THE INVENTION
[0019] The disclosure provides a heat transfer system having a
tubing coil for heating fluid flowing therein, where the tubing
coil can be pigged (descaled) while operationally online, instead
of offline. The online system uses an assembly of valves and
associated equipment to connect to a pig launcher and pig receiver
while the system is online. A valve opens and the pig launches into
the flow stream under pressure through the valve and travels along
the tube with the fluid. The system continues to produce heated
fluid with the pig in the flow path. A pig receiver receives the
pig after the pigging, and then is isolated from the flow path of
the heated fluid by another valve. The pig launcher, pig receiver,
and pig are removed, and this process is repeated for any other
passes in the tubing coil. In at least one embodiment, the heat
transfer system can include a heat recovery steam generator system,
such as a once-through steam generator System ("OTSG").
[0020] The disclosure provides a heat transfer system, comprising:
a heat source coupled to a chamber having a tubing coil disposed
therein, the heat source adapted to heat at least a portion of a
fluid in the tubing coil into a heated fluid, the tubing coil
having an inlet and an outlet, the inlet adapted to receive the
fluid for flowing through a flow path in the tubing coil and the
outlet adapted to allow the heated fluid to exit the tubing coil; a
first inlet connection coupled to the inlet for coupling with a
supply line to supply the fluid into the tubing coil; a second
inlet connection coupled to the inlet and fluidicly independent of
the first inlet connection; an inlet valve coupled to the second
inlet connection; a third inlet connection coupled to the inlet
valve; a pig launcher coupled to the third inlet connection, the
pig launcher adapted to launch a pig into the tubing coil through
the inlet valve; a first outlet connection coupled to the outlet
and adapted to allow the heated fluid to exit therethrough; a
second outlet connection coupled to the outlet and fluidicly
independent of the first outlet connection; an outlet valve coupled
to the second outlet connection; a third outlet connection coupled
to the outlet valve; and a pig receiver coupled to the third outlet
connection, the pig receiver adapted to receive the pig from the
tubing coil through the outlet valve. The heat transfer system can
include a heat recovery steam generator, where the fluid in the
tubing coil includes feedwater, and the heated fluid includes
steam.
[0021] The disclosure also provides a method of pigging a heat
transfer system, the system having a heat source coupled to a
chamber having a tubing coil disposed therein, the tubing coil
having one or more tubing passes, the heat source adapted to heat
at least a portion of a fluid in the tubing coil into a heated
fluid, the tubing coil having an inlet and an outlet, the inlet
adapted to receive the fluid for flowing through a flow path in the
tubing coil, and the outlet adapted to allow the heated fluid to
exit the tubing coil, the system further having: a first inlet
connection coupled to the inlet for coupling with a supply line to
supply the fluid into the tubing coil; an inlet valve coupled to
the inlet fluidicly independent of the first inlet connection; a
pig launcher coupled to the inlet valve, the pig launcher adapted
to launch a pig into the tubing coil through the inlet valve; a
first outlet connection coupled to the outlet and adapted to allow
the heated fluid to exit therethrough; an outlet valve coupled to
the outlet fluidicly independent of the first outlet connection;
and a pig receiver coupled to the outlet valve, the pig receiver
adapted to receive the pig from the tubing coil through the outlet
valve, the method comprising: maintaining operation of the system
by continuing to supply the fluid through the first inlet
connection into the tubing coil; opening the inlet valve; launching
the pig into a tubing pass of the tubing coil through the inlet
valve and into a flow path of the fluid; descaling tubing surfaces
of the tubing pass while continuing to generate the heated fluid in
the tubing pass; opening the outlet valve; ejecting the pig through
the outlet valve into the pig receiver; and flowing the heated
fluid generated upstream and downstream of the pig in the tubing
pass through the outlet independent of the outlet valve.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0022] FIG. 1 is a representative schematic diagram of a fire
heater for heating hydrocarbon in a tubing coil.
[0023] FIG. 2 is a representative schematic diagram of an OTHRSG
system with a tubing coil.
[0024] FIG. 3 is a representative schematic diagram of an OTSG
system.
[0025] FIG. 4 is a schematic perspective view of an OTSG facility
for extraction of hydrocarbon from oil sands.
[0026] FIG. 5 is a schematic cross sectional side view of the OTSG
unit producing steam for extraction of hydrocarbon from the oil
sands.
[0027] FIG. 6 is a side schematic view of an OTSG unit adapted to
be operated online.
[0028] FIG. 7 is a top schematic view of the OTSG unit adapted to
be operated online.
[0029] FIG. 8 is a schematic view of an exemplary tubing coil
having multiple passes.
[0030] FIG. 9 is a schematic view of an exemplary tubing coil
having a single pass.
[0031] FIG. 10 is a schematic view of an exemplary tubing coil
having multiple passes with valving and related connections adapted
to allow online operation of the OTSG system.
[0032] FIG. 11 is a schematic view of an exemplary tubing coil
having a single pass with valving and related connections adapted
to allow online operation of the OTSG system.
DETAILED DESCRIPTION
[0033] The Figures described above and the written description of
specific structures and functions below are not presented to limit
the scope of what Applicant has invented or the scope of the
appended claims. Rather, the Figures and written description are
provided to teach any person skilled in the art how to make and use
the inventions for which patent protection is sought. Those skilled
in the art will appreciate that not all features of a commercial
embodiment of the inventions are described or shown for the sake of
clarity and understanding. Persons of skill in this art will also
appreciate that the development of an actual commercial embodiment
incorporating aspects of the present inventions will require
numerous implementation-specific decisions to achieve the
developer's ultimate goal for the commercial embodiment. Such
implementation-specific decisions may include, and likely are not
limited to, compliance with system-related, business-related,
government-related and other constraints, which may vary by
specific implementation, location, and from time to time. While a
developer's efforts might be complex and time-consuming in an
absolute sense, such efforts would be, nevertheless, a routine
undertaking for those of ordinary skill in this art having benefit
of this disclosure. It must be understood that the inventions
disclosed and taught herein are susceptible to numerous and various
modifications and alternative forms. The use of a singular term,
such as, but not limited to, "a," is not intended as limiting of
the number of items. Also, the use of relational terms, such as,
but not limited to, "top," "bottom," "left," "right," "upper,"
"lower," "down," "up," "side," and the like are used in the written
description for clarity in specific reference to the Figures and
are not intended to limit the scope of the invention or the
appended claims. Where appropriate, some elements have been labeled
with an alphabetic character after a number to reference a specific
member of the numbered element to aid in describing the structures
in relation to the Figures, but is not limiting in the claims
unless specifically stated. When referring generally to such
members, the number without the letter is used. Further, such
designations do not limit the number of members that can be used
for that function.
[0034] The disclosure provides a heat transfer system having a
tubing coil for heating fluid flowing therein, where the tubing
coil can be pigged (descaled) while operationally online, instead
of offline. The online system uses an assembly of valves and
associated equipment to connect to a pig launcher and pig receiver
while the system is online. A valve opens and the pig launches into
the flow stream under pressure through the valve and travels along
the tube with the fluid. The system continues to produce heated
fluid with the pig in the flow path. A pig receiver receives the
pig after the pigging, and then is isolated from the flow path of
the heated fluid by another valve. The pig launcher, pig receiver,
and pig are removed, and this process is repeated for any other
passes in the tubing coil.
[0035] As discussed above, heat transfer systems having tubing
coils are used in a number of applications. For the purposes of
illustration, a heat transfer system will be described in terms of
an OTHRSG system, and particularly, an OTSG system. However, it is
understood that the examples herein are non-limiting, as the
inventive concept and technical solution can be applied to other
heat transfer systems having a tubing coil for heating a fluid
disposed therein. Thus, for example, while the heat source can be
described as a burner that heats from fuel combustion, as is
generally used in an OTSG system, the heat source can also include
a turbine exhaust, a turbine exhaust coupled to a burner,
electrical heating through resistive heating or induction heating,
combinations thereof, and any other type of heating that can
provide heat to a tubing coil for fluid therein. Similarly, while
the fluid is described in terms of feedwater and the heated fluid
as steam, as is generally used in an OTSG system, the fluid can
also include any flowable substance that can be flowed in a tubing
coil, including without limitation hydrocarbons and other organic
fluids, and other flowable substances. Thus, while the OTSG is
described in some detail relevant to the inventive concepts, the
exemplary components described herein should be understood to
encompass similar functional components in other heat transfer
systems. For example, the heat source in the following figures,
shown as a burner, should be understood to also include other known
types of heat sources, such as, but not limited to, the types of
heat sources in the above list and shown as a block diagram in FIG.
5 above.
[0036] FIG. 6 is a side schematic view of an OTSG unit adapted to
be operated online. FIG. 7 is a top schematic view of the OTSG unit
adapted to be operated online. FIG. 8 is a schematic view of an
exemplary tubing coil having multiple passes. FIG. 9 is a schematic
view of an exemplary tubing coil having a single pass. The figures
will be described in conjunction with each other.
[0037] A heat transfer system, such as an OTSG system, 2 includes
an OTSG unit 8 generally described above with additional valving
and other associated equipment adapted to allow the OTSG unit to
operate online while pigging. A heat source 10, such as a burner,
produces heat that is directed into the OTSG unit heating chamber
15 that generally includes a heated fluid zone, such as a steam
generation zone 14, and a fluid preheat zone 12, such as for
incoming feedwater. A tubing coil 16 is disposed in one or more
portions of the chamber 15. The tubing coil 16 can include multiple
tubing passes, such as tubing passes 17A, 17B, 17C, illustrated in
FIG. 8, or a single tubing pass 17, illustrated in FIG. 9,
generally referenced as tubing pass 17. Each tubing pass 17
generally includes an accessible inlet 18 and outlet 20 with an
inlet valve and outlet valve coupled thereto, described in more
detail in reference to FIGS. 10 and 11 below.
[0038] FIG. 10 is a schematic view of an exemplary tubing coil
having multiple passes with valving and associated equipment
adapted to allow online operation of the OTSG system. The chamber
15 contains a majority of the tubing coil 16 that is used to heat
the fluid, such as feedwater, into a heated fluid, such as
principally steam. The tubing coil generally includes one or more
tubing passes 17, such as tubing passes 17A, 17B. This portion of
the OTSG system is prone to developing the scale on the tube walls
of the tubing passes and need periodic descaling.
[0039] The portion of the online OTSG system 8 shown in FIG. 10
includes valving and associated equipment arranged and coupled to
the inlet 18 and the outlet 20 of the tubing coil 16 to allow the
online OTSG system to continue to operate while pigging. For
example, the tubing pass 17A includes an inlet 18 is fluidicly
coupled to an inlet connection 46 for the supply of fluid, such as
the feedwater, into the tubing pass. However, in the exemplary
illustrated online OTSG system, the tubing pass 17A, and more
generally the tubing coil 16, is also fluidicly coupled independent
of the first inlet connection to a second inlet connection 40 for
coupling to a removable pig launcher 36, known in the art. The
connection 40 is coupled to an inlet valve 42. The valve 42 is
coupled to another inlet connection 44. The connection 44 can be
coupled during operation of the OTSG system to the removable pig
launcher 36. Thus, the connection 46 for the feedwater and the
connection 40 for the pigging form two distinct points of access
into the inlet 18 of the tubing coil 16. One or more of the pig
launcher 36, valve 42, and connections 40, 44 can be longitudinally
aligned with a longitudinal axis 60 of the tubing pass 17A at the
inlet 18, and more generally that portion of the tubing coil
adjacent the connection 40, to facilitate the pig 58 being injected
into the flow path of the tubing pass 17. In at least one
embodiment, the inlet connection 46 for the supply of feedwater
into the tubing pass 17A will be nonaligned with the longitudinal
axis. The connections can be a flange, threaded connection, quick
disconnect, or other means of coupling two elements together.
Further, the connections can be separate or integral with another
element, such as a valve or spool having a connection on each
end.
[0040] Similarly, the tubing pass 17A includes an outlet 20
fluidicly coupled to an outlet connection 48 for allowing the steam
and any remaining heated feedwater to exit from the tubing pass. In
the exemplary illustrated online OTSG system, the tubing pass 17A,
and more generally the tubing coil 16, is also fluidicly coupled
independent of the first outlet connection 48 to a second outlet
connection 50 for coupling to a pig receiver 38, known in the art.
The connection 50 is coupled to an outlet valve 52. The valve 52 is
coupled to another outlet connection 54. The connection 54 can be
coupled during operation of the OTSG system to the pig receiver 38.
Thus, the connection 48 and the connection 50 form two distinct
points of exit from the outlet 20 of the tubing coil 16. One or
more of the pig receiver 38, valve 52, and connections 50, 54 can
be longitudinally aligned with a longitudinal axis 60 of the tubing
pass 17A at the outlet 20, and more generally that portion of the
tubing coil adjacent the connection 50, to facilitate the pig being
ejected from the tubing pass and received into the pig receiver. In
at least one embodiment, the outlet connection 48 for the exit of
steam from the tubing pass 17A will be nonaligned with the
longitudinal axis. Another connection 56 can be used as an
additional access point to the tubing pass.
[0041] Each tubing pass can have an inlet valve and outlet valve
coupled thereto so that the pig launcher and pig retriever can be
coupled to the valves while the OTSG system is online. Thus, the
OTSG system 8 can remain online producing the heated fluid, such as
the steam, during set up and assembly operations of the pig
launcher 36 and pig receiver 38 in preparation for a pigging
operation to the tubing pass 17A. When the equipment is assembled
and the pigging is about to be initiated, the valve 42 can be
opened to expose the pig launcher 36 and a pig 58 in the pig
launcher to the inlet 18 of the tubing pass 17A. Similarly, the
valve 52 can be opened to expose the pig receiver 38 to the outlet
of the tubing pass 17A.
[0042] The pig 58 is launched into the flow path of the
feedwater/steam in the inlet 18. The launch can be actuated by
higher pressure water or the forces on the pig into the flow path.
The pig 58 travels along the tubing pass 17A to descale the tubular
internal surfaces with the feedwater pressure pushing the pig. The
OTSG system is continuing to heat the tubing pass and produce steam
downstream and upstream of the pig 58 in the normal course of
operation. As the pig 58 ends the travel in the tubing pass 17A,
the pig enters a portion of the tubing pass that is aligned with
the valve 52 and pig receiver 52. The mass of the pig 58 along the
flow path provides inertia to the pig to continue generally
straight through the valve 52 and into the pig receiver 38.
However, the steam in the tubing pass 17A exits the outlet 20 to
continue to provide steam to the underground oil sands for
production thereof. The valves 42, 52 can be closed to isolate the
pig launcher 36, pig receiver 38, and pig 58 in the pig receiver 38
from the flow path of the feedwater and steam through the tubing
pass 17A.
[0043] For tubing coils having multiple tubing passes, generally
each tubing pass has an inlet, an outlet, an inlet valve coupled to
the inlet, and an outlet valve coupled to the outlet. The pig
launcher 36, pig receiver 38, and pig 58 can be removed from the
valves on the tubing pass 17A, and assembled in similar manner to
valves on the tubing pass 17B for pigging the tubing pass 17B, and
so forth until all tubing passes for the OTSG unit are
descaled.
[0044] Thus, the OTSG unit can remain online with all tubing passes
operating at full or substantially full load producing steam at
significantly less expense to the overall system in maintaining
operational throughput.
[0045] FIG. 11 is a schematic view of an exemplary tubing coil
having a single pass with valving and related connections adapted
to allow online operation of the OTSG system. In a similar fashion
as described above for FIG. 10, the online OTSG system can be
pigged without requiring the OTSG system to stop operation in an
offline mode. The valving and connections are mounted with the
tubing coil to allow the pig launcher 36 and pig receiver 38 to be
connected to the tubing coil 16 having a tubing pass 17 while the
tubing coil is operational. The valve 42 can be opened and the pig
58 injected into the flow path of the feedwater through the tubing
pass 17 and is energized by the feedwater behind the pig to push
the pig through the internal portions of the tubing pass 17 while
steam is generated through the pass. The pig receiver 38 receives
the pig 58 through an open valve 52, and the steam exits the tubing
coil 16. The valves 42 and 52 can be closed to isolate the pig
launcher 36 and pig receiver 38 from the flow path through the
tubing coil and the pig launcher and pig receiver disconnected to
be used on another tubing pass or tubing coil of another OTSG
unit.
[0046] Some of the potential advantages of the online OTSG system
include: [0047] reduced capital expenditures and operational
expenditures, at least in part, due to a reduced need of having
extra OTSG units to operate while an OTSG unit is placed offline
for pigging; [0048] potentially reduced footprint without a need
for an extra OTSG unit to maintain steam production while an OTSG
unit is offline; potentially more flexibility in design without the
extra OTSG unit as restraints on the design, placement, piping,
controls, and other factors associated with an additional unit;
[0049] increased steam production for existing systems having extra
OTSG units by having all OTSG units online without having to be
offline for pigging; and [0050] potentially reduced maintenance,
including labor and materials, with the long term impact of
additional thermal stresses on shutting down and restarting OTSG
units.
[0051] Other and further embodiments utilizing one or more aspects
of the invention described above can be devised without departing
from the spirit of the invention. For example, the exemplary heat
transfer system can be used in other environments besides
production from oil sands. Further, the heat transfer system can be
used for different types of fluids including hydrocarbons and other
organic fluids, including gases. Thus, the invention applies to any
heat transfer system having a tubing coil used for any application.
Further, different connections and equipment can be used for a
variety of connections and valves for the invention and the
embodiments of connections and valves are exemplary without
limitation. Other variations in the system are possible.
[0052] Further, the various methods and embodiments described
herein can be included in combination with each other to produce
variations of the disclosed methods and embodiments. Discussion of
singular elements can include plural elements and vice-versa.
References to at least one item followed by a reference to the item
may include one or more items. Also, various aspects of the
embodiments could be used in conjunction with each other to
accomplish the understood goals of the disclosure. Unless the
context requires otherwise, the word "comprise" or variations such
as "comprises" or "comprising," should be understood to imply the
inclusion of at least the stated element or step or group of
elements or steps or equivalents thereof, and not the exclusion of
a greater numerical quantity or any other element or step or group
of elements or steps or equivalents thereof. The device or system
may be used in a number of directions and orientations. The term
"coupled," "coupling," "coupler," and like terms are used broadly
herein and may include any method or device for securing, binding,
bonding, fastening, attaching, joining, inserting therein, forming
thereon or therein, communicating, or otherwise associating, for
example, mechanically, magnetically, electrically, chemically,
operably, directly or indirectly with intermediate elements, one or
more pieces of members together and may further include without
limitation integrally forming one functional member with another in
a unitary fashion. The coupling may occur in any direction,
including rotationally.
[0053] The order of steps can occur in a variety of sequences
unless otherwise specifically limited. The various steps described
herein can be combined with other steps, interlineated with the
stated steps, and/or split into multiple steps. Similarly, elements
have been described functionally and can be embodied as separate
components or can be combined into components having multiple
functions.
[0054] The invention has been described in the context of preferred
and other embodiments and not every embodiment of the invention has
been described. Apparent modifications and alterations to the
described embodiments are available to those of ordinary skill in
the art given the disclosure contained herein. The disclosed and
undisclosed embodiments are not intended to limit or restrict the
scope or applicability of the invention conceived of by the
Applicant, but rather, in conformity with the patent laws,
Applicant intends to protect fully all such modifications and
improvements that come within the scope or range of equivalent of
the following claims.
* * * * *