U.S. patent application number 14/255476 was filed with the patent office on 2014-09-04 for heat exchanger for an oil storage tank.
The applicant listed for this patent is Lester James Thiessen. Invention is credited to Lester James Thiessen.
Application Number | 20140245972 14/255476 |
Document ID | / |
Family ID | 51420284 |
Filed Date | 2014-09-04 |
United States Patent
Application |
20140245972 |
Kind Code |
A1 |
Thiessen; Lester James |
September 4, 2014 |
Heat Exchanger for an Oil Storage Tank
Abstract
A heating assembly for heating a liquid storage tank includes a
heat exchanger tank supported in one wall of the storage tank to
extend into the storage tank in contact with liquid stored therein.
The heat exchanger tank contains a heat exchanger fluid therein
which is heated by a heating apparatus extending through the heat
exchanger tank whereby heat is only transferred to the liquid in
the storage tank through the heat exchanger fluid. The heating
apparatus extending through the heat exchanger tank may be a burner
tube or an electrical resistance-type heating element according to
different embodiments of the invention.
Inventors: |
Thiessen; Lester James;
(Neilburg, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Thiessen; Lester James |
Neilburg |
|
CA |
|
|
Family ID: |
51420284 |
Appl. No.: |
14/255476 |
Filed: |
April 17, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14178919 |
Feb 12, 2014 |
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14255476 |
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61763603 |
Feb 12, 2013 |
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Current U.S.
Class: |
122/18.3 ;
122/19.1; 392/456 |
Current CPC
Class: |
B65D 88/748 20130101;
F24H 1/186 20130101; F24H 1/185 20130101; F24H 9/1818 20130101;
B65D 88/744 20130101; F24H 9/1836 20130101; F24H 9/146
20130101 |
Class at
Publication: |
122/18.3 ;
122/19.1; 392/456 |
International
Class: |
B65D 88/74 20060101
B65D088/74; F24H 9/12 20060101 F24H009/12 |
Claims
1. A heating assembly for heating a liquid storage tank having
walls surrounding a hollow interior arranged to contain a liquid
therein, the assembly comprising: a heat exchanger tank including
boundary walls containing a heat exchanger fluid therein; a heating
apparatus supported within the heat exchanger tank; the heat
exchanger tank being arranged to be supported within the liquid
storage tank such that heat from the heating apparatus is arranged
to be communicated through the heat exchanger fluid and the
boundary walls of the heat exchanger tank directly to liquid in the
liquid storage tank.
2. The assembly according to claim 1 wherein the heat exchanger
tank is arranged to be supported within the oil storage tank such
that heat is only communicated from the heating apparatus to the
liquid in the storage tank through the heat exchanger fluid.
3. The assembly according to claim 1 wherein the heat exchanger
tank is arranged to be supported in sealing engagement with one of
the walls of the oil storage tank.
4. The assembly according to claim 1 wherein the heat exchanger
tank is arranged to extend generally horizontally inward from an
upright boundary wall of the storage tank.
5. The assembly according to claim 1 in combination with a
production tank arranged to receive produced hydrocarbons therein
directly from a well.
6. The assembly according to claim 1 further comprising an overflow
tank located externally of the heat exchanger tank and an overflow
passage in communication between the overflow tank and the heat
exchanger tank so as to be arranged to permit expansion of the heat
exchanger fluid from the heat exchanger tank into the overflow
tank.
7. The assembly according to claim 1 further comprising a fluid
level monitor arranged to monitor a level of heat exchanger fluid
in the heat exchanger tank, and a controller arranged to cease
operation of the heating apparatus responsive to a level of the
heat exchanger fluid as monitored by the fluid level monitor
falling below a prescribed lower level limit.
8. The assembly according to claim 1 further comprising a heat
exchanger temperature monitor arranged to monitor a temperature of
the heat exchanger fluid in the heat exchanger tank, and a
controller arranged to cease operation of the heating apparatus
responsive to a temperature of the heat exchanger fluid as
monitored by the heat exchanger temperature monitor exceeding a
prescribed upper temperature limit.
9. The assembly according to claim 1 further comprising a heat
exchanger temperature monitor arranged to monitor a temperature of
the heat exchanger fluid in the heat exchanger tank, and a
controller arranged to actuate operation of the heating apparatus
responsive to a temperature of the heat exchanger fluid as
monitored by the heat exchanger temperature monitor falling below a
prescribed lower temperature limit.
10. The assembly according to claim 1 further comprising a storage
temperature monitor arranged to monitor a temperature of the liquid
in the liquid storage tank, and a controller arranged to cease
operation of the heating apparatus responsive to a temperature of
the liquid as monitored by the storage temperature monitor
exceeding a prescribed upper temperature limit.
11. The assembly according to any one of claims 1 through 10
wherein the heat exchanger tank includes a perimeter flange
projecting outwardly from the boundary walls about a circumference
of the heat exchanger tank, the perimeter flange being arranged to
be mounted in sealing engagement about a perimeter of an opening in
the wall of the oil storage tank.
12. The assembly according to claim 11 wherein the perimeter flange
is defined by a perimeter edge of an end wall at one end of the
heat exchanger tank.
13. The assembly according to claim 11 wherein the perimeter flange
includes spaced apart mounting apertures formed therein so as to be
arranged to secure the flange to the perimeter of the opening in
the wall of the oil storage tank using threaded fasteners.
14. The assembly according to claim 1 wherein the heat exchanger
fluid comprises heat transfer oil.
15. The assembly according to claim 1 further comprising a
production passage communicating through the heat exchanger tank
from an inlet end of the production passage arranged to receive
produced fluid from a well therein to outlet of the production
passage arranged for communication with the hollow interior of the
storage tank such that the production passage is in heat exchanging
relationship with the heating apparatus through the heat exchanger
fluid.
16. The assembly according to claim 15 wherein the production
passage follows a sinuous path through the heat exchanger tank.
17. The assembly according to claim 15 wherein the production
passage is above the heating assembly.
18. The assembly according to claim 1 wherein the heating apparatus
comprises a burner tube extending through the heat exchanger tank
and being arranged to be coupled to an external burner so as to
direct exhaust from the burner therethrough.
19. The assembly according to claim 1 wherein the heating apparatus
comprises an electrical resistance-type heating element extending
through the heat exchanger tank.
20. A method of producing hydrocarbons from a well comprising a
wellhead, the method comprising: providing a storage tank in
proximity to the well having an interior storage chamber for
storing produced hydrocarbons therein; providing a heating assembly
comprising: a heat exchanger tank received within the interior of
the storage chamber of the storage tank, the heat exchanger tank
including boundary walls containing a heat exchanger fluid therein;
and a heating apparatus supported within the heat exchanger tank;
directing produced hydrocarbons from the well into the interior
storage chamber of the storage tank; and heating the produced
hydrocarbons in the interior storage chamber of the storage tank by
actuating the heating apparatus such that heat from the heating
apparatus is arranged to be communicated through the heat exchanger
fluid and the boundary walls of the heat exchanger tank directly to
the produced hydrocarbons in the storage tank.
Description
[0001] This application is a continuation-in-part of US parent
application Ser. No. 14/178,919, filed Feb. 12, 2014, and claims
the benefit under 35 U.S.C.119(e) of U.S. provisional application
Ser. No. 61/763,603, filed Feb. 12, 2013.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat exchanger arranged
to be received in a storage tank, for example an oil storage tank,
in which the each exchanger contains a heat exchanger fluid therein
and receives a heating apparatus extending therethrough for heating
the contents in the storage tank by communicating heat from the
heating apparatus through the heat exchanger fluid. The heating
apparatus may comprise a burner tube of a propane burner or an
electrical resistance-type heating element. More particularly, the
present invention relates to a heat exchanger for a heating
apparatus in an oil storage tank which further includes a
production passage extending through the heat exchanger fluid in
the heat exchanger tank for heating produced hydrocarbons as they
are directed through the production passage into the oil storage
tank.
BACKGROUND
[0003] In oil production, it is common to locate an oil storage
tank at an oil well site to produce hydrocarbons from the well
directly into the oil storage tank. It is also known to provide a
propane burner which directs exhaust into a burner tube extending
into the oil storage tank for heating oil in the tank. Heating the
oil assist in settling sand out of the oil to the bottom of the
tank and assists with fluidity of the oil when subsequently pumping
the oil into transport tanker trucks.
[0004] Occasionally oil is pumped from the oil storage tank into
tanker trucks such that the level of oil in the storage tank falls
below the elevation of the burner tube in the storage tank. The
burner tube in this instance can become excessively hot such that
there is danger of igniting volatile hydrocarbons in gaseous form
surrounding the burner tube. Ignition of the fumes can cause
explosions which damage the tank and are a safety concerns for
operators of the storage tank or tanker trucks.
[0005] U.S. Pat. No. 7,726,298 by St. Denis discloses a method and
apparatus for heating a liquid storage tank in place of a
conventional burner tube. An engine is disposed in an engine
compartment appended to a peripheral sidewall of the tank and an
exhaust conduit extends into the interior of the liquid storage
tank from the engine such that heat from hot exhaust gases passing
through the exhaust conduit heats the interior of the liquid
storage tank. The exhaust conduit can still become excessively hot
and is in direct contact with volatile hydrocarbons in the storage
tank such that the same risk of ignition and explosions as noted
above remains present.
[0006] U.S. Pat. No. 7,293,606 by Benoit discloses a heat
exchanging apparatus including a gas fuelled flameless catalytic
heater. According to one embodiment, an oil storage tank is heated
by locating the catalytic heater remotely from the tank and
communicating heat exchanger fluid in a loop between the catalytic
heater and a heater coil in the tank. Although the risk of
combustion within the oil storage tank may be reduced as compared
to use of a burner tube, the heater coil can be difficult to
maintain as it is subjected to abrasive sands and corrosive fluids
within the oil storage tank.
[0007] Electrical resistant heater coils have been used by
immersion within various prior art fluid tanks, such as residential
hot water tanks; however, when used within a hydrocarbon storage
tank for heating the oil therein, the heater coil is subjected to
abrasive sands and corrosive fluids within the oil storage tank.
Variation the diameter of the coil can produce dangerous hot spots.
Also, the heat transfer through the contents within a hydrocarbon
storage tank typically relies on conduction through the
hydrocarbons as the heavy fluid involves minimal fluid movement,
particularly when there is an abundance of sludge and sand therein,
such that the very small heat transfer area of the heater coil is
very inefficient at evenly distributing heat throughout the storage
tank.
SUMMARY OF THE INVENTION
[0008] According to one aspect of the invention there is provided a
heating assembly for heating a liquid storage tank having walls
surrounding a hollow interior arranged to contain a liquid therein,
the assembly comprising:
[0009] a heat exchanger tank including boundary walls containing a
heat exchanger fluid therein;
[0010] a heating apparatus supported within the heat exchanger
tank;
[0011] the heat exchanger tank being arranged to be supported
within the liquid storage tank such that heat from the heating
apparatus is arranged to be communicated through the heat exchanger
fluid and the boundary walls of the heat exchanger tank directly to
liquid in the liquid storage tank.
[0012] The heating apparatus may comprises a burner tube extending
through the heat exchanger tank and being arranged to be coupled to
an external burner so as to direct exhaust from the burner
therethrough, or an electrical resistance-type heating element
extending through the heat exchanger tank.
[0013] The heat exchanger fluid surrounding the heating apparatus
maintains fluid contact with the heating apparatus to prevent the
heating apparatus from reaching excessive temperature which could
otherwise risk igniting vapours in the oil storage tank. The heat
exchanger tank also limits direct contact of the heating apparatus
with hydrocarbons in the storage tank to further minimize the risk
of igniting hydrocarbons in the oil storage tank.
[0014] The heat exchanger tank received within the oil storage
compartment of the oil storage tank allows heat to be transferred
directly from the heat exchanger fluid, through the boundary walls
of the heat exchanger tank, directly to the surrounding oil in the
storage tank. The heat exchanger tank occupies a much larger volume
than the heating element alone for more even transfer of heat to
the surrounding oil in the storage tank. Furthermore, the heat
exchange tank fully surrounds the heating element such that the
heating element is fully protected from abrasive sands and
corrosive fluids within the storage tank.
[0015] Preferably the heat exchanger tank is arranged to be
supported within the oil storage tank such that heat is only
communicated from the heating apparatus to the liquid in the
storage tank through the heat exchanger fluid.
[0016] Preferably the heat exchanger tank is arranged to be
supported in sealing engagement with one of the walls of the oil
storage tank.
[0017] Preferably the heat exchanger tank is arranged to extend
generally horizontally inward from an upright boundary wall of the
storage tank.
[0018] The heat exchanger tank may be used in combination with a
production tank arranged to receive produced hydrocarbons therein
directly from a well.
[0019] Preferably the heat exchanger tank further comprises an
overflow tank located externally of the heat exchanger tank and an
overflow passage in communication between the overflow tank and the
heat exchanger tank so as to be arranged to permit expansion of the
heat exchanger fluid from the heat exchanger tank into the overflow
tank.
[0020] Preferably a fluid level monitor is arranged to monitor a
level of heat exchanger fluid in the heat exchanger tank. In this
instance the controller may be arranged to cease operation of the
heating apparatus responsive to a level of the heat exchanger fluid
as monitored by the fluid level monitor falling below a prescribed
lower level limit.
[0021] Preferably a heat exchanger temperature monitor is arranged
to monitor a temperature of the heat exchanger fluid in the heat
exchanger tank. In this instance the controller may be arranged to
cease operation of the heating apparatus responsive to a
temperature of the heat exchanger fluid as monitored by the heat
exchanger temperature monitor exceeding a prescribed upper
temperature limit.
[0022] Preferably a heat exchanger temperature monitor is arranged
to monitor a temperature of the heat exchanger fluid in the heat
exchanger tank. In this instance the controller may be arranged to
actuate operation of the heating apparatus responsive to a
temperature of the heat exchanger fluid as monitored by the heat
exchanger temperature monitor falling below a prescribed lower
temperature limit.
[0023] Preferably a storage temperature monitor is arranged to
monitor a temperature of the liquid in the liquid storage tank. In
this instance the controller may be arranged to cease operation of
the heating apparatus responsive to a temperature of the liquid as
monitored by the storage temperature monitor exceeding a prescribed
upper temperature limit.
[0024] Preferably the heat exchanger tank includes a perimeter
flange projecting outwardly from the boundary walls about a
circumference of the heat exchanger tank in which the perimeter
flange is arranged to be mounted in sealing engagement about a
perimeter of an opening in the wall of the oil storage tank.
[0025] Preferably the perimeter flange is defined by a perimeter
edge of an end wall at one end of the heat exchanger tank.
[0026] Preferably the perimeter flange includes spaced apart
mounting apertures formed therein so as to be arranged to secure
the flange to the perimeter of the opening in the wall of the oil
storage tank using threaded fasteners.
[0027] Preferably the heat exchanger fluid comprises heat transfer
oil.
[0028] Preferably a production passage communicates through the
heat exchanger tank between an inlet end of the production passage
arranged to receive produced fluid from a well therein and outlet
of the production passage arranged for communication with the
hollow interior of the storage tank such that the production
passage is in heat exchanging relationship with the heating
apparatus through the heat exchanger fluid.
[0029] Preferably the production passage follows a sinuous path
through the heat exchanger tank.
[0030] Preferably the production passage is above the heating
assembly.
[0031] According to a further aspect of the present invention there
is provided method of producing hydrocarbons from a well comprising
a wellhead, the method comprising:
[0032] providing a storage tank in proximity to the well having an
interior storage chamber for storing produced hydrocarbons
therein;
[0033] providing a heating assembly comprising: [0034] a heat
exchanger tank received within the interior of the storage chamber
of the storage tank, the heat exchanger tank including boundary
walls containing a heat exchanger fluid therein; and [0035] a
heating apparatus supported within the heat exchanger tank;
[0036] directing produced hydrocarbons from the well into the
interior storage chamber of the storage tank; and
[0037] heating the produced hydrocarbons in the interior storage
chamber of the storage tank by actuating the heating apparatus such
that heat from the heating apparatus is arranged to be communicated
through the heat exchanger fluid and the boundary walls of the heat
exchanger tank directly to the produced hydrocarbons in the storage
tank.
[0038] Various embodiments of the invention will now be described
in conjunction with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a perspective view of a first embodiment of the
heating assembly;
[0040] FIG. 2 is a sectional view of the heating assembly according
to the first embodiment along the line 2-2 in FIG. 1.
[0041] FIG. 3 is a perspective view of the heating assembly
according to the first embodiment of FIG. 1, shown supported on a
horizontal tank;
[0042] FIG. 4 is a perspective view of the heating assembly
according to the first embodiment of FIG. 1, shown supported on an
upright tank;
[0043] FIG. 5 is a schematic representation of a sectional view
along the line 2-2 in FIG. 1 according to a second embodiment;
[0044] FIG. 6 is a perspective view of a third embodiment of the
heating assembly; and
[0045] FIG. 7 is a sectional view of the heating assembly according
to the third embodiment along the line 7-7 in FIG. 6.
[0046] In the drawings like characters of reference indicate
corresponding parts in the different figures.
DETAILED DESCRIPTION
[0047] Referring to the accompanying figures, there is illustrated
a heating assembly generally indicated by reference numeral 10. The
assembly 10 is suited for heating a liquid storage tank 12 having
tank boundary walls 14 surrounding the hollow interior which
defines a main liquid storage portion for storing liquid, for
example oil therein.
[0048] According to the first and second embodiments of FIGS. 1
through 5, the heating assembly 10 is used with a burner head 16,
for example a propane burner and is mounted within the oil storage
tank in place of a conventional burner tube extending into the tank
for heating the oil therein.
[0049] According to the third embodiment of FIGS. 6 and 7, the
heating assembly 10 is used with an electrical resistance-type
heating apparatus 15, and is mounted within the oil storage tank
instead of a conventional electric heater coil. Contrary to the
present invention, a conventional electric heater coil would be
mounted to extend directly into the oil storage tank in direct
communication with the oil in the storage tank for heating the oil
therein.
[0050] Although various embodiments are shown in the accompanying
figures, the common features of the first and second embodiments
will first be described.
[0051] The assembly 10 is mounted into a suitable opening 18 formed
in an upright one of the walls 14 of the tank. A heat exchanger
tank 20 of the assembly extends into the storage tank through the
opening 18 so as to be elongate and extend generally horizontally
inward into the tank from a first end 22 at the wall of the tank to
an inner second end 24. The tank 20 is fully closed on all sides by
respective side walls 26 and enclosed at both of the first and
second ends by respective ends walls 28 such that the interior of
the heat exchanger tank is a fixed closed volume containing a heat
exchanger fluid therein which fills the tank.
[0052] At the first end of the tank 20, the end wall 28 comprises a
generally vertically oriented end plate which protrudes beyond the
side walls about the full perimeter edge thereof to define a
perimeter flange 30 extending about a full circumference of the
heat exchanger tank at the first end thereof. The perimeter flange
overlaps the side wall of the oil storage tank within which the
heat exchanger tank is mounted about the full perimeter of the
opening 18. Mounting apertures 32 are located at circumferentially
spaced positions about the perimeter flange so as to permit
mounting to the tank wall about the perimeter of the opening using
suitable threaded fasteners for example. A gasket 34 may be
provided about the perimeter of the opening 18 of the tank wall to
be clamped between the storage tank and the perimeter mounting
flange of the heat exchanger tank so that the heat exchanger tank
is mounted in sealing engagement with the storage tank wall about
the full perimeter thereof.
[0053] The assembly further includes a burner tube 36 which is
generally U-shaped so as to comprise two elongate sections 38
extending horizontally and longitudinally substantially between the
first and second ends of the heat exchanger tank. The two sections
38 are joined at the second end of the tank by a curved section to
define the U-shape of the burner tube.
[0054] A lowermost one of the two sections 38 protrudes through the
end wall 28 at the first end of the tank to define an inlet of an
exhaust passage defined by the burner tube. A suitable bolt flange
40 about the inlet permits coupling to a burner head 16 for
receiving the products of combustion therefrom in use to heat the
burner tube and thus heat the oil in the storage tank as described
in further detail below.
[0055] The uppermost section 38 of the burner tube similarly
protrudes through the end wall 28 at the first end of the heat
exchanger tank above the inlet. The portion of the second section
protruding to the exterior is coupled to a vertical stack 42 to
define an outlet of the exhaust passage defined by the burner tube
which is vented to atmosphere.
[0056] The main portion of the burner tube between the inlet and
outlet ends thereof as defined primarily by the first and second
sections 38 and the curved section therebetween is fully contained
within the heat exchanger tank. The heat exchanger tank is in turn
mounted within the storage tank wall so that the main portion of
the burner tube is the only portion received within the storage
tank and also such that the main portion is fully surrounded by
heat exchanger fluid contained within the heat exchanger tank. In a
preferred embodiment, the heat exchanger fluid is a heat transfer
oil. Regardless of the type of heat exchanger fluid, the heat
exchanger tank is mounted such that heat can only be communicated
from the burner tube to the oil in the main oil storage portion of
the storage tank through the heat exchanger fluid in the heat
exchanger tank. This ensures no direct communication between the
burner tube and the oil in the storage tank.
[0057] In use, the heating assembly is installed in a storage tank
by providing a suitable opening in the upright wall of the tank so
that the heat exchanger tank can be substantially fully inserted
into the oil storage tank to extend longitudinally and horizontally
inward from the first end of the tank wall to the second end
terminating internally within the oil storage tank. Using the
gasket and bolts through the perimeter mounting flange the first
end of the heat exchanger tank is mounted in sealing engagement
about the perimeter of the opening in the storage tank wall.
[0058] The burner head is coupled to the inlet of the burner tube
and operated such that the products of combustion from the burner
head are directed through the burner tube from the inlet to the
outlet to heat up the burner tube and in turn heat up the heat
exchanger fluid surrounding the burner tube. The heat transferred
to the fluid is in turn transferred to the oil through the
increased exterior surface area of the heat exchanger tank.
[0059] As shown in FIG. 3, when the tank includes a cylindrical
wall extending horizontally between two opposing end walls, the
heat exchanger tank is typically mounted in one of the upright end
walls.
[0060] Alternatively, as shown in FIG. 4, when the storage tank
comprises an upright cylindrical side wall, typically the heat
exchanger tank is mounted in an opening in the cylindrical
wall.
[0061] Turning now more particularly to the first embodiment of
FIGS. 1 through 4, the assembly 10 in this instance further
includes a production passage 44 in the form of an elongate pipe
extending through the heat exchanger tank to be surrounded by heat
exchanger fluid therein. The production passage extends from a
first end protruding through the end wall 28 at the first end of
the heat exchanger tank at a location below the burner tube to a
second end which is open to the hollow interior of the main oil
storage portion of the storage tank. Although the passage 44 is
shown below in FIGS. 1 through 5, in preferred embodiments, the
passage 44 is located above the burner tube.
[0062] The first end of the production passage includes the bolt
flange 46 at the exterior of the heat exchanger tank to permit
coupling to suitable oil production equipment to receive produced
oil directly therein, thus defining an inlet 48 of the production
passage. Produced fluids are communicated from the inlet towards an
opposing outlet 50 defined by the second end of the production
passage at the second end of the heat exchanger tank.
[0063] The production passage is comprised of plural lengths of
pipe joined by curved sections to define a sinuous path from the
inlet to the outlet through the heat exchanger fluid. The winding
and non-linear path of the production passage increases the
duration that the produced fluids are in heat exchanging
relationship with the heat exchanger fluid.
[0064] Connecting oil production equipment to the inlet of the
production passage also allows heat to be transferred from the
burner tube to the produced fluids in the production passage 44 by
transferring heat across the heat exchanger fluid in the heat
exchanger tank surrounding both the burner tube and the production
passage.
[0065] Turning now more particularly to the embodiment of FIG. 5,
the structure of the heat exchanger tank is substantially identical
to the embodiment of FIGS. 1 through 4; however, additional
controls are provided. In further embodiments, the additional
controls may also be used in combination with the production
passage 44.
[0066] As shown in FIG. 5, a controller 60 is provided which
controls operation of the burner head 16. The controller 60 works
in cooperation with various sensors as described herein. One of the
sensors is a heat exchanger temperature monitor 64 mounted on the
outer end wall 28 of the heat exchanger tank 20 at an intermediate
height between the burner head and the exhaust portion of the
burner tube. The heat exchanger temperature monitor 64 is arranged
to monitor a temperature of the heat exchanger fluid in the heat
exchanger tank. The monitored temperature is relayed to the
controller with all other monitored data. In this instance, the
controller 60 is arranged to both: i) actuate operation of the
burner head responsive to a temperature of the heat exchanger fluid
as monitored by the heat exchanger temperature monitor falling
below a prescribed lower temperature limit, and ii) cease operation
of the burner head responsive to a temperature of the heat
exchanger fluid as monitored by the heat exchanger temperature
monitor exceeding a prescribed upper temperature limit. The heat
exchanger is thus maintained substantially between the upper and
lower temperature limits.
[0067] A storage temperature monitor 66 is also provided for
monitoring a temperature of the liquid in the liquid storage tank.
The storage temperature monitor 66 is supported in the boundary
wall of the storage tank, spaced apart laterally from the heat
exchanger tank, at an elevation which is near a vertical center of
the storage tank and the heat exchanger tank respectively. The
storage temperature monitor communicates through the boundary wall
of the storage tank so as to be in contact with the liquid stored
in the storage tank 12. The controller 60 in this instance is
arranged to cease operation of the burner head responsive to a
temperature of the liquid as monitored by the storage temperature
monitor exceeding a prescribed upper temperature limit regardless
of the condition sensed by the heat exchanger temperature monitor.
More particularly, if the liquid temperature in the storage tank
exceeds the respective upper storage temperature limit, the burner
head is not operated even if the heat exchanger temperature monitor
indicates a temperature below the upper limit thereof.
[0068] Another one of the sensors associated with the controller is
a fluid level monitor 62 which is supported on the outer end wall
28 of the heat exchanger tank 20 to communicate through the end
wall with fluid inside the tank. More particularly, the fluid level
monitor 62 is arranged to monitor a level of heat exchanger fluid
in the heat exchanger tank by determining if the fluid is in
contact with the monitor or not. The monitor is mounted above the
height of the burner tubes to define a minimum operational height
of the liquid. The controller 60 monitors if fluid is in contact
with the monitor 62 to determine if the height of the fluid is
above or below the level of the monitor 62. Accordingly the
controller can be arranged to cease operation of the burner head 16
responsive to a level of the heat exchanger fluid falling below a
prescribed lower level limit defined by the location of the monitor
as indicated by a lack of fluid contact with the monitor 62. The
operation of the burner head is prevented in the instance of a
fluid level below the fluid level monitor 62 even if the
temperature monitors indicate a heating demand.
[0069] Also shown in FIG. 5, an overflow tank 68 is supported
externally of the storage tank 12 and the heat exchanger tank 20 by
being supported along an exterior of the outer end wall 28 of the
heat exchanger tank and along an exterior of one of the boundary
walls of the storage tank 12. The overflow tank 68 locates a
surplus of the heat exchanger fluid therein. The overflow tank 68
is elongate in a vertical direction and is supported such that a
majority of the tank extends upwardly above the top end of the heat
exchanger tank 20. An overflow passage 70 in the form of a small
diameter tube or pipe is in open fluid communication between a
bottom end of the overflow tank and a top end of the heat exchanger
tank so as to be arranged to permit expansion of the heat exchanger
fluid from the heat exchanger tank into the overflow tank and so as
to ensure the heat exchanger tank remains always full in its
entirety with heat exchanger fluid. The top end of the overflow
tank includes a vent 72 which is vented to atmospheric
pressure.
[0070] FIG. 5 further illustrates a drain fitting 74 in
communication through the outer end wall 28 of the heat exchanger
tank 20 adjacent the bottom end thereof. The drain fitting 74 can
be capped or provided with a valve to maintain the fitting in a
closed state under normal operation. The drain fitting is typically
only opened when it is desired to drain the heat exchanger fluid
from the heat exchanger tank, for example when performing
maintenance on the assembly.
[0071] A thermometer 76 can also be mounted externally on the outer
end wall 28 of the heat exchanger tank to display temperature of
the fluid within the heat exchanger tank as measured by the
thermometer in communication with the fluid.
[0072] The assembly according to FIG. 5 is operated in the manner
described above to heat contents of the storage tank for treatment
and the like. In a preferred embodiment, the storage tank receives
produced hydrocarbons therein which may be heated for example to
assist in the settling of sand from the oil. The controller 60
receives data from the various monitors described above and
operates the burner head to maintain the heat exchanger fluid
between upper and lower limits, while simultaneously ensuring that
the temperature of the contents of the storage tank remain between
upper and lower limits. For added safety, the burner is prevented
from operating if the fluid level in the heat exchanger tank falls
below a prescribed limit.
[0073] Turning now to the third embodiment of FIGS. 6 and 7, the
assembly 10 is again mounted into a storage tank opening 18 formed
in an upright one of the walls 14 of the tank. The tank in this
instance includes a collar 19 which is joined to the perimeter edge
of the wall 14 of the tank about the tank opening 18, to project
perpendicularly outward from the wall concentrically with the tank
opening 18. A mounting flange 21 extends radially outwardly from
the collar 19, about the full perimeter of the tank opening 18. The
mounting flange lies parallel to and spaced outwardly from the tank
wall 14 such that the assembly 10 may be readily fastened thereto
as described in further detail below.
[0074] A heat exchanger tank 20 of the assembly extends into the
storage tank through the opening 18 so as to be elongate in a
longitudinal direction extending generally horizontally inward into
the tank from a first end 22 at the wall of the tank to an inner
second end 24. The tank 20 is fully closed on all sides by
respective side walls 26 and enclosed at both of the first and
second ends by respective ends walls 28 such that the interior of
the heat exchanger tank is a fixed volume containing a heat
exchanger fluid therein, for example a heat transfer oil or glycol,
which fills the tank.
[0075] At the first end of the tank 20, the end wall 28 comprises a
generally vertically oriented end plate which protrudes beyond the
side walls about the full perimeter edge thereof to define a
perimeter flange 30 extending about a full circumference of the
heat exchanger tank at the first end thereof. The perimeter flange
overlaps the mounting flange 21 about the tank opening 18 within
which the heat exchanger tank is received. Co-operating mounting
apertures 32 in the mounting flange 21 of the storage tank and the
perimeter flange 30 of the heating assembly permit fasteners to
secure the flanges together about the full perimeter of the opening
18 using suitable threaded fasteners for example. An annular gasket
34 may be provided between the flanges prior to fastening so that
the gasket is received about the full circumference of the opening
18, clamped between the storage tank and the perimeter mounting
flange of the heat exchanger tank. Accordingly, the heat exchanger
tank is mounted in sealing engagement with the storage tank wall
about the full perimeter thereof.
[0076] The heating apparatus 15 includes a resistance type heating
element 37 which is submerged within the heat exchanger fluid in
the heat exchanger tank, and a controller 61 which regulates
electrical power delivered to the heating element 37 to produce
heat. The heating element includes a plurality of winding sections
39 which follow a sinuous path substantially evenly distributed
throughout the volume of the heat exchanger tank to provide
substantially uniform heat to the heat exchanger fluid within the
heat exchanger tank. A sealed port 41 communicates the heat element
37 through the exterior end wall 28 in sealing engagement with the
end wall to prevent the escape of heat exchanger fluid
therethrough.
[0077] The heating element is fully received and contained within
the heat exchanger tank, and in turn, the heat exchanger tank is
mounted within the storage tank wall so that the heat exchanger
tank is substantially fully received within the interior storage
volume of the oil storage tank. Although in the preferred
embodiment the heat exchanger fluid is a heat transfer oil,
regardless of the type of heat exchanger fluid, the heat exchanger
tank is mounted such that heat can only be communicated from the
heating element to the oil in the main oil storage portion of the
storage tank through the heat exchanger fluid in the heat exchanger
tank. This ensures no direct communication between the heating
element and the oil in the storage tank.
[0078] The heating assembly 10 optionally further includes a
production passage 44 in the form of an elongate pipe extending
through the heat exchanger tank to be surrounded by heat exchanger
fluid therein. The production passage extends from a first end
protruding through the end wall 28 at the first end of the heat
exchanger tank at a location above the heating element to a second
end which is open to the hollow interior of the main oil storage
portion of the storage tank.
[0079] The first end of the production passage includes the bolt
flange 46 at the exterior of the heat exchanger tank to permit
coupling to suitable oil production equipment to receive produced
oil directly therein, thus defining an inlet 48 of the production
passage. Produced fluids are communicated from the inlet towards an
opposing outlet 50 defined by the second end of the production
passage at the second end of the heat exchanger tank.
[0080] The production passage is comprised of plural lengths of
pipe joined by curved sections to define a sinuous path from the
inlet to the outlet through the heat exchanger fluid. The winding
and non-linear path of the production passage increases the
duration that the produced fluids are in heat exchanging
relationship with the heat exchanger fluid.
[0081] Connecting oil production equipment to the inlet of the
production passage also allows heat to be transferred upwardly from
the heating element to the produced fluids in the production
passage 44 by transferring heat across the heat exchanger fluid in
the heat exchanger tank surrounding both the heating element and
the production passage.
[0082] With regard to operation of the heating element, the
controller 61 works in cooperation with various sensors as
described herein. One of the sensors is a heat exchanger
temperature monitor 64 mounted on the outer end wall 28 of the heat
exchanger tank 20 at an intermediate height which is centrally
located between the top and bottom ends of the heat exchanger tank.
The heat exchanger temperature monitor 64 is arranged to monitor a
temperature of the heat exchanger fluid in the heat exchanger tank.
The monitored temperature is relayed to the controller with all
other monitored data.
[0083] In this instance, the controller 61 is arranged to both: i)
actuate operation of the electric heating element responsive to a
temperature of the heat exchanger fluid as monitored by the heat
exchanger temperature monitor falling below a prescribed lower
temperature limit, and ii) cease operation of the electric heating
element responsive to a temperature of the heat exchanger fluid as
monitored by the heat exchanger temperature monitor exceeding a
prescribed upper temperature limit. The heat exchanger is thus
maintained substantially between the upper and lower temperature
limits.
[0084] A storage temperature monitor 66 is also provided for
monitoring a temperature of the liquid in the liquid storage tank.
The storage temperature monitor 66 is supported in the boundary
wall of the storage tank, spaced apart laterally from the heat
exchanger tank, at an elevation which is near a vertical center of
the storage tank and the heat exchanger tank respectively. The
storage temperature monitor communicates through the boundary wall
of the storage tank so as to be in contact with the liquid stored
in the storage tank 12.
[0085] The controller 61 in this instance is arranged to cease
operation of the electric heating element responsive to a
temperature of the liquid as monitored by the storage temperature
monitor exceeding a prescribed upper temperature limit regardless
of the condition sensed by the heat exchanger temperature monitor.
More particularly, if the liquid temperature in the storage tank
exceeds the respective upper storage temperature limit, the
electric heating element is not operated even if the heat exchanger
temperature monitor indicates a temperature below the upper limit
thereof.
[0086] Another one of the sensors associated with the controller is
a fluid level monitor 62 which is supported on the outer end wall
28 of the heat exchanger tank 20 to communicate through the end
wall with fluid inside the tank. More particularly, the fluid level
monitor 62 is arranged to monitor a level of heat exchanger fluid
in the heat exchanger tank by determining if the fluid is in
contact with the monitor or not. The monitor is mounted above the
height of an uppermost portion of the heating element to define a
minimum operational height of the liquid.
[0087] The controller 61 monitors if fluid is in contact with the
monitor 62 to determine if the height of the fluid is above or
below the level of the monitor 62. Accordingly the controller can
be arranged to cease operation of the electrical heating element
responsive to a level of the heat exchanger fluid falling below a
prescribed lower level limit defined by the location of the monitor
as indicated by a lack of fluid contact with the monitor 62. The
operation of the electric heating element is prevented in the
instance of a fluid level below the fluid level monitor 62 even if
the temperature monitors indicate a heating demand.
[0088] The heating assembly also includes an overflow tank 68 which
is supported externally of the storage tank 12 and the heat
exchanger tank 20 by being supported along an exterior of the outer
end wall 28 of the heat exchanger tank and along an exterior of one
of the boundary walls of the storage tank 12. The overflow tank 68
locates a surplus of the heat exchanger fluid therein. The overflow
tank 68 is elongate in a vertical direction and is supported such
that a majority of the tank extends upwardly above the top end of
the heat exchanger tank 20. An overflow passage 70 in the form of a
small diameter tube or pipe is in open fluid communication between
a bottom end of the overflow tank and a top end of the heat
exchanger tank so as to be arranged to permit expansion of the heat
exchanger fluid from the heat exchanger tank into the overflow tank
and so as to ensure the heat exchanger tank remains always full in
its entirety with heat exchanger fluid. The top end of the overflow
tank includes a vent 72 which is vented to atmospheric
pressure.
[0089] A drain fitting 74 is also provided in communication through
the outer end wall 28 of the heat exchanger tank 20 adjacent the
bottom end thereof. The drain fitting 74 can be capped or provided
with a valve to maintain the fitting in a closed state under normal
operation. The drain fitting is typically only opened when it is
desired to drain the heat exchanger fluid from the heat exchanger
tank, for example when performing maintenance on the assembly.
[0090] A thermometer 76 can also be mounted externally on the outer
end wall 28 of the heat exchanger tank to display temperature of
the fluid within the heat exchanger tank as measured by the
thermometer in communication with the fluid.
[0091] In use, the heating assembly is installed in a storage tank
by providing a suitable opening 18 in the upright wall of the tank
with a corresponding mounting flange about the opening so that the
heat exchanger tank can be substantially fully inserted into the
oil storage tank to extend longitudinally and horizontally inward
from the first end of the tank wall to the second end terminating
internally within the oil storage tank. Using the gasket and bolts
through the perimeter mounting flange the first end of the heat
exchanger tank is mounted in sealing engagement about the perimeter
of the opening in the storage tank wall.
[0092] As shown in FIG. 3, when the tank includes a cylindrical
wall extending horizontally between two opposing end walls, the
heat exchanger tank is typically mounted in one of the upright end
walls.
[0093] Alternatively, as shown in FIG. 4, when the storage tank
comprises an upright cylindrical side wall, typically the heat
exchanger tank is mounted in an opening in the cylindrical
wall.
[0094] The heating assembly 10 is operated as described above to
heat contents of the storage tank for treatment and the like. In a
preferred embodiment, the storage tank receives produced
hydrocarbons therein, which may be heated, for example to assist in
the settling of sand from the oil. The controller 61 receives data
from the various monitors described above and operates the
electrical heating element to maintain temperature of the heat
exchanger fluid between upper and lower limits, while
simultaneously ensuring that the temperature of the contents of the
storage tank remains between upper and lower limits. For added
safety, the heating element is prevented from operating if the
fluid level in the heat exchanger tank falls below a prescribed
limit.
[0095] Since various modifications can be made in my invention as
herein above described, and many apparently widely different
embodiments of same made within the spirit and scope of the claims
without department from such spirit and scope, it is intended that
all matter contained in the accompanying specification shall be
interpreted as illustrative only and not in a limiting sense.
* * * * *