U.S. patent application number 12/191095 was filed with the patent office on 2009-01-08 for vapor containment and electrical power generation.
Invention is credited to James W. Healy.
Application Number | 20090007983 12/191095 |
Document ID | / |
Family ID | 41669236 |
Filed Date | 2009-01-08 |
United States Patent
Application |
20090007983 |
Kind Code |
A1 |
Healy; James W. |
January 8, 2009 |
Vapor Containment and Electrical Power Generation
Abstract
A fuel vapor and energy conservation system includes one or more
liquid fuel storage tanks connected to at least one fuel dispenser
for delivering liquid fuel to vehicle fuel tanks and a
motor/generator set powered by the evaporated fuel vapor and/or
liquid fuel, used alone or in combination to generate electrical
power. In some implementations, the fuel vapor and energy
conservation system also includes a vapor conservation system with
a tank defining a tank volume and a bladder disposed within the
tank volume and defining a bladder volume for receiving fuel vapor
from the ullage space, the tank and the bladder defining an air
space external of the bladder, with a system of vapor conduit for
conducting evaporated fuel vapor between the ullage space and the
bladder volume and a system of air conduit for conducting air into
and out of the air space external of the bladder.
Inventors: |
Healy; James W.; (Hollis,
NH) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Family ID: |
41669236 |
Appl. No.: |
12/191095 |
Filed: |
August 13, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11744541 |
May 4, 2007 |
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12191095 |
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Current U.S.
Class: |
141/7 ;
141/59 |
Current CPC
Class: |
B67D 7/0476
20130101 |
Class at
Publication: |
141/7 ;
141/59 |
International
Class: |
B65B 31/00 20060101
B65B031/00 |
Claims
1. A fuel vapor and energy conservation system, comprising: a
liquid fuel dispensing system comprising: one or more liquid fuel
storage tanks connected to at least one liquid fuel dispenser for
delivering liquid fuel to vehicle fuel tanks, the one or more fuel
storage tanks defining ullage space containing evaporated fuel
vapor above an interface with liquid fuel; a vapor conservation
system comprising: a tank defining a tank volume, and a bladder
disposed within the tank volume and defining a bladder volume for
receiving fuel vapor, the tank and the bladder defining an air
space external of the bladder; a system of vapor conduit for
conducting evaporated fuel vapor between the ullage space and the
bladder volume; a system of air conduit for conducting air into and
out of the air space external of the bladder; and an electrical
power generation system comprising a motor/generator set powered at
least by the evaporated fuel vapor to generate electrical
power.
2. A fuel vapor and energy conservation system, comprising: a
liquid fuel dispensing system comprising: one or more liquid fuel
storage tanks connected to at least one liquid fuel dispenser for
delivering liquid fuel to vehicle fuel tanks, the one or more fuel
storage tanks defining ullage space containing evaporated fuel
vapor above an interface with liquid fuel; and an electrical power
generation system comprising a motor/generator set powered at least
by the evaporated fuel vapor to generate electrical power.
3. The fuel vapor and energy conservation system of claim 2,
further comprising: a vapor conservation system comprising: a tank
defining a tank volume, and a bladder disposed within the tank
volume and defining a bladder volume for receiving fuel vapor from
the ullage space, the tank and the bladder defining an air space
external of the bladder; a system of vapor conduit for conducting
evaporated fuel vapor between the ullage space and the bladder
volume; and a system of air conduit for conducting air into and out
of the air space external of the bladder.
4. The fuel vapor and energy conservation system of claim 1 or
claim 2, further comprising: a vapor shut-off and flow control
valve disposed in a fuel vapor inlet conduit for regulating volume
flow of evaporated fuel vapor to the motor of the motor/generator
set; an air inlet valve disposed in an air inlet conduit for
regulating volume flow of air to the motor of the motor/generator
set; and an air/fuel ratio sensor disposed is an air and fuel vapor
flow conduit in communication with the air inlet conduit and with
the fuel vapor conduit; and an electrical controller; the air/fuel
ratio sensor being disposed in electrical communication with the
controller for signaling the ratio of air to fuel delivered to the
motor; and the controller being in communication with the air flow
control valve and the vapor shut-off and flow control valve for
signaling adjustment of flow of air in the air inlet conduit and/or
flow of evaporated fuel vapor in the fuel vapor conduit, thereby to
adjust and maintain a desired ratio in a mixture of the fuel vapor
and the air delivered to power the motor of the motor/generator
set.
5. The fuel vapor and energy conservation system of claim 4 wherein
the motor of the motor/generator set is selectively powered by
liquid fuel and the system further comprises: a liquid fuel
shut-off disposed in a liquid fuel conduit in communication between
a source of liquid fuel and a carburetor, the carburetor being
disposed in communication with the liquid fuel conduit and the air
intake conduit, and the controller being in communication with the
air flow control valve and the liquid fuel shut-off for signaling
adjustment of flow of air in the air inlet conduit and flow of
liquid fuel in the liquid fuel conduit, thereby to adjust and
maintain a desired ratio in a mixture of the fuel and the air
delivered by the carburetor to power the motor of the
motor/generator set.
6. The fuel vapor and energy conservation system of claim 5,
wherein the motor/generator set is powered by evaporated fuel vapor
and/or by liquid fuel, used alone or in combination.
7. The fuel vapor and energy conservation system of claim 1 or
claim 2, wherein the motor/generator provides power at least for
operation of the vehicle fueling service station.
8. The fuel vapor and energy conservation system of claim 1 or
claim 2, wherein the motor/generator provides power at least for
delivery into a utility power grid.
9. The fuel vapor and energy conservation system of claim 1 or
claim 2, wherein the system further comprises a starter and battery
for initiating operation of the motor in the motor/generator
set.
10. The fuel vapor and energy conservation system of claim 1 or
claim 2, further comprising an air filter disposed in the air inlet
conduit.
11. The fuel vapor and energy conservation system of claim 1 or
claim 2, further comprising a flame arrestor in the fuel vapor
conduit.
12. The fuel vapor and energy conservation system of claim 1 or
claim 2, wherein the controller issues signals for activation and
deactivation of the motor/generator set in response to at least one
condition selected from among the following group of conditions:
Phase 1 hose connection, UST vapor space pressure, manual
start/stop button, and external power supply.
13. The fuel vapor conservation system of claim 1 or claim 3,
wherein the system of vapor conduit further comprises a conduit
system for delivery of fuel vapor displaced from the ullage space
by addition of liquid fuel to the one or more fuel storage tanks
into the bladder volume, and for delivery of fuel vapor from the
bladder volume back into the ullage space as liquid fuel is
dispensed from the one or more liquid fuel storage tanks.
14. The fuel vapor conservation system of claim 13, wherein the
system of vapor conduit further comprises a conduit system for
delivery of fuel vapor from the bladder volume back into the ullage
space as liquid fuel is dispensed from the one or more liquid fuel
storage tanks into vehicle fuel tanks over time.
15. The fuel vapor conservation system of claim 13, wherein the
system of vapor conduit further comprises a float check valve for
restricting flow of liquid fuel toward the bladder volume.
16. The fuel vapor conservation system of claim 1 or claim 3,
wherein the system of air conduit further comprises a conduit
system for delivery of the air displaced from the air space of the
vapor conservation tank into the ullage space of a liquid fuel
delivery vehicle, replacing a volume of liquid fuel delivered from
the liquid fuel delivery vehicle.
17. The fuel vapor conservation system of claim 1 or claim 3,
wherein the system of air conduit further comprises a conduit
system for delivery of the air displaced from the air space of the
vapor conservation tank into the ambient environment.
18. The fuel vapor conservation system of claim 1 or claim 3,
wherein the bladder is inflatable and collapsible.
19. The fuel vapor conservation system of claim 1 or claim 3,
wherein the bladder is formed of thin wall, flexible material.
20. The fuel vapor conservation system of claim 19, wherein the
bladder is formed of resilient material.
21. A method of conserving fuel vapor in a liquid fuel dispensing
system comprising one or more liquid fuel storage tanks connected
to at least one dispenser for delivering liquid fuel to vehicle
fuel tanks, a volume of liquid fuel dispensed from the one or more
liquid fuel storage tanks being replaced by a volume of air, said
method comprising: connecting ullage space of the one or more
liquid fuel storage tanks to a bladder within a vapor conservation
tank; delivering liquid fuel into the one or more liquid fuel
storage tanks, the liquid fuel displacing evaporated fuel vapor
from the one or more liquid fuel storage tanks; delivering
displaced evaporated fuel vapor into the bladder, the delivered
evaporated fuel vapor inflating the bladder and displacing air from
the air space of the vapor conservation tank external of the
bladder; thereafter, over time, delivering evaporated fuel vapor
from the bladder of the vapor conservation tank into ullage space
of the one or more liquid fuel storage tanks, replacing the volume
of liquid fuel delivered from the one or more liquid fuel storage
tanks into vehicle fuel tanks; and using at least evaporated fuel
vapor to operate a motor/generator set for generation of electrical
power.
22. The method of claim 21, comprising using at least a portion of
the electrical power for operation of a vehicle fueling service
station.
23. The method of claim 22, comprising contributing a portion of
the electrical power to a local power grid.
24. The method of claim 21, further comprising: delivering liquid
fuel from a liquid fuel delivery vehicle into the one or more
liquid fuel storage tanks.
25. The method of claim 24, further comprising: connecting ullage
space of the liquid fuel delivery vehicle to air space of the vapor
conservation tank containing the bladder, external of the bladder;
and delivering the air displaced from the air space of the vapor
conservation tank into the ullage space of the liquid fuel delivery
vehicle, the displaced air replacing a volume of the liquid fuel
delivered from the liquid fuel delivery vehicle.
26. The method of claim 21, further comprising: delivering the air
displaced from the air space of the vapor conservation tank into
the ambient environment.
27. The method of claim 21, comprising the further step of:
connecting one or more underground storage tanks to a vapor
conservation tank in the form of an auxiliary tank containing the
bladder.
28. The method of claim 21, comprising the further step of:
connecting one or more underground storage tanks to a vapor
conservation tank in the form of an aboveground auxiliary tank
containing the bladder.
29. The method of claim 21, comprising the further steps of:
converting an underground storage tank to a vapor conservation tank
containing the bladder; and connecting one or more underground
storage tanks to the vapor conservation tank in the form of the
converted underground storage tank containing the bladder.
Description
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 11/744,541, filed, May 4, 2007, now pending,
the complete disclosure of which is incorporated by reference
herein.
TECHNICAL FIELD
[0002] This disclosure relates to underground fuel storage tanks,
and more particularly to systems for containment and conservation
of fuel vapor from such tanks, including for generation of
electrical power.
BACKGROUND
[0003] Vehicle fueling service stations in some regions of the
United States, i.e. those regions where only Phase I (i.e.
non-Phase II) vapor recovery is mandated, and in many other
countries, operate with limited or no restrictions on release of
fuel vapors into the environment, e.g. including fuel vapors
generated by evaporation of liquid fuel into the ullage space of
vehicle and underground storage tanks, and then displaced from the
tank by entering liquid fuel during filling. Even vehicle fueling
service stations operating under the more stringent controls of
Phase I and Phase II vapor recovery can under some circumstances,
release fuel vapors into the environment.
[0004] When a service station dispenses gasoline to customer
vehicles, the liquid gasoline level in the underground storage tank
("UST") will fall. The space created in the UST as gasoline level
falls produces a vacuum. This vacuum causes ambient air to enter
the UST, e.g., via leaks in the tanks and the associated vapor
piping network, including through the tank vent relief valve, if
one has been installed. The inflow of air causes evaporation of
liquid gasoline at the interface of liquid gasoline and air until
an equilibrium condition is achieved. As the rate of gasoline sales
diminishes, or when the service station closes for the night,
evaporation of gasoline into the less-than-saturated air will
continue, which causes the volume of gases in the vapor space to
expand, raising the pressure in the UST vapor space. This condition
leads to the loss of gasoline vapor to the environment, including
through the same leakage paths that permitted ambient air to enter
the UST ullage space during periods of negative pressure.
[0005] This loss of fuel in its vapor state is recognized as a
detriment to the environment. Over an extended period of fueling
operations, it can also represent a substantial loss of product,
and loss of potential profit, to the service station owner and
operator.
SUMMARY
[0006] According to one aspect of the disclosure, a fuel vapor and
energy conservation system comprises a liquid fuel dispensing
system comprising one or more liquid fuel storage tanks connected
to at least one liquid fuel dispenser for delivering liquid fuel to
vehicle fuel tanks, the one or more fuel storage tanks defining
ullage space containing evaporated fuel vapor above an interface
with liquid fuel; a vapor conservation system comprising a tank
defining a tank volume, and a bladder disposed within the tank
volume and defining a bladder volume for receiving fuel vapor, the
tank and the bladder defining an air space external of the bladder;
a system of vapor conduit for conducting evaporated fuel vapor
between the ullage space and the bladder volume; a system of air
conduit for conducting air into and out of the air space external
of the bladder; and an electrical power generation system
comprising a motor/generator set powered by at least the evaporated
fuel vapor to generate electrical power.
[0007] According to another aspect of the disclosure, a fuel vapor
and energy conservation system comprises a liquid fuel dispensing
system comprising one or more liquid fuel storage tanks connected
to at least one liquid fuel dispenser for delivering liquid fuel to
vehicle fuel tanks, the one or more fuel storage tanks defining
ullage space containing evaporated fuel vapor above an interface
with liquid fuel; and an energy generation system comprising a
motor/generator set powered at least by the evaporated fuel vapor
to generate electrical power.
[0008] Preferred implementations of this aspect of the disclosure
may include one or more of the following additional features. The
fuel vapor and energy conservation system further comprises a vapor
conservation system comprising a tank defining a tank volume, and a
bladder disposed within the tank volume and defining a bladder
volume for receiving fuel vapor from the ullage space, the tank and
the bladder defining an air space external of the bladder; a system
of vapor conduit for conducting evaporated fuel vapor between the
ullage space and the bladder volume; and a system of air conduit
for conducting air into and out of the air space external of the
bladder.
[0009] Preferred implementations of both aspects of the disclosure
may include one or more of the following additional features. The
fuel vapor and energy conservation system further comprises a vapor
shut-off and flow control valve disposed in a fuel vapor inlet
conduit for regulating volume flow of evaporated fuel vapor to the
motor of the motor/generator set; an air inlet valve disposed in an
air inlet conduit for regulating volume flow of air to the motor of
the motor/generator set; and an air/fuel ratio sensor disposed is
an air and fuel vapor flow conduit in communication with the air
inlet conduit and with the fuel vapor conduit; and an electrical
controller; the air/fuel ratio sensor being disposed in electrical
communication with the controller for signaling the ratio of air to
fuel delivered to the motor; and the controller being in
communication with the air flow control valve and the vapor
shut-off and flow control valve for signaling adjustment of flow of
air in the air inlet conduit and/or flow of evaporated fuel vapor
in the fuel vapor conduit, thereby to adjust and maintain a desired
ratio in a mixture of the fuel vapor and the air delivered to power
the motor of the motor/generator set. The motor of the
motor/generator set is selectively powered by liquid fuel and the
system further comprises a liquid fuel shut-off disposed in a
liquid fuel conduit in communication between a source of liquid
fuel and a carburetor, the carburetor being disposed in
communication with the liquid fuel conduit and the air intake
conduit, and the controller being in communication with the air
flow control valve and the liquid fuel shut-off for signaling
adjustment of flow of air in the air inlet conduit and flow of
liquid fuel in the liquid fuel conduit, thereby to adjust and
maintain a desired ratio in a mixture of the fuel and the air
delivered by the carburetor to power the motor of the
motor/generator set. The motor/generator set is powered by
evaporated fuel vapor and/or by liquid fuel, used alone or
preferably in combination, to achieve a desired air/fuel ratio. The
motor/generator provides power at least for operation of the
vehicle fueling service station. The motor/generator provides power
at least for delivery into a utility power grid. The system further
comprises a starter and battery for initiating operation of the
motor in the motor/generator set. The fuel vapor and energy
conservation system further comprises an air filter disposed in the
air inlet conduit. The fuel vapor and energy conservation system
further comprises a flame arrestor in the fuel vapor conduit. The
controller issues signals for activation and deactivation of the
motor/generator set in response to at least one condition selected
from among the following group of conditions: Phase 1 hose
connection, UST vapor space pressure, manual start/stop button, and
external power supply. The system of vapor conduit further
comprises a conduit system for delivery of fuel vapor displaced
from the ullage space by addition of liquid fuel to the one or more
fuel storage tanks into the bladder volume, and for delivery of
fuel vapor from the bladder volume back into the ullage space as
liquid fuel is dispensed from the one or more liquid fuel storage
tanks. The system of vapor conduit further comprises a conduit
system for delivery of fuel vapor from the bladder volume back into
the ullage space as liquid fuel is dispensed from the one or more
liquid fuel storage tanks into vehicle fuel tanks over time. The
system of vapor conduit further comprises a float check valve for
restricting flow of liquid fuel toward the bladder volume. The
system of air conduit further comprises a conduit system for
delivery of the air displaced from the air space of the vapor
conservation tank into the ullage space of a liquid fuel delivery
vehicle, replacing a volume of liquid fuel delivered from the
liquid fuel delivery vehicle. The system of air conduit further
comprises a conduit system for delivery of the air displaced from
the air space of the vapor conservation tank into the ambient
environment. The bladder is inflatable and collapsible. The bladder
is formed of thin wall, flexible material. The bladder is formed of
resilient material.
[0010] According to still another aspect of the invention, a method
of conserving fuel vapor in a liquid fuel dispensing system
comprising one or more liquid fuel storage tanks connected to at
least one dispenser for delivering liquid fuel to vehicle fuel
tanks, a volume of liquid fuel dispensed from the one or more
liquid fuel storage tanks being replaced by a volume of air,
comprises connecting ullage space of the one or more liquid fuel
storage tanks to a bladder within a vapor conservation tank;
delivering liquid fuel into the one or more liquid fuel storage
tanks, the liquid fuel displacing evaporated fuel vapor from the
one or more liquid fuel storage tanks; delivering displaced
evaporated fuel vapor into the bladder, the delivered evaporated
fuel vapor inflating the bladder and displacing air from the air
space of the vapor conservation tank external of the bladder;
thereafter, over time, delivering evaporated fuel vapor from the
bladder of the vapor conservation tank into ullage space of the one
or more liquid fuel storage tanks, replacing the volume of liquid
fuel delivered from the one or more liquid fuel storage tanks into
vehicle fuel tanks; and using at least evaporated fuel vapor to
operate a motor/generator set for generation of electrical
power.
[0011] Preferred implementations of this aspect of the disclosure
may include one or more of the following additional features. The
method further comprises using at least a portion of the electrical
power for operation of a vehicle fueling service station. The
method further comprises contributing a portion of the electrical
power to a local power grid. The method further comprises
delivering liquid fuel from a liquid fuel delivery vehicle into the
one or more liquid fuel storage tanks. The method further comprises
connecting ullage space of the liquid fuel delivery vehicle to air
space of the vapor conservation tank containing the bladder,
external of the bladder; and delivering the air displaced from the
air space of the vapor conservation tank into the ullage space of
the liquid fuel delivery vehicle, the displaced air replacing a
volume of the liquid fuel delivered from the liquid fuel delivery
vehicle. The method further comprises delivering the air displaced
from the air space of the vapor conservation tank into the ambient
environment.
[0012] This disclosure thus describes a system for generation of
electric power by use of gasoline vapor contained and conserved
during normal operations of a vehicle fueling service station,
e.g., by a vapor containment system described in my U.S. patent
application Ser. No. 11/744,541. In one implementation, the
gasoline vapors collected in the vapor containment bladder are
optionally consumed as fuel in a gasoline motor/generator employed
as an energy source to produce electric power for the benefit of
the service station owner. The disclosed system will have
application in service stations with both Phase I and Phase II
vapor recovery equipment, and in those service stations with only
Phase I vapor recovery equipment. The disclosed system will also
have application in service stations without vapor recovery
equipment, such as is the case in developing countries.
[0013] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a somewhat diagrammatic representation of a
typical (prior art) gasoline service station during a fuel "drop"
or delivery, e.g. in the United States where only Phase I (i.e.
non-Phase II) vapor recovery is mandated, and in other
countries.
[0015] FIG. 2 is a somewhat diagrammatic representation of a Phase
I gasoline service station of the type depicted in FIG. 1 during a
fuel drop, the service station being equipped with one
implementation of a fuel vapor containment system of the
disclosure, the vapor containment tank being aboveground.
[0016] FIG. 3 is a somewhat diagrammatic side section view of a
slightly different implementation of the fuel vapor containment
system of FIG. 2 with an aboveground vapor containment tank.
[0017] FIG. 4 is a somewhat diagrammatic enlarged side section view
of the bladder support assembly for the fuel vapor containment
system of FIG. 3.
[0018] FIG. 5 is a somewhat diagrammatic representation of another
implementation of a gasoline vapor containment system of the
disclosure, the fuel vapor containment tank being underground.
[0019] FIG. 6 is an end view of the underground fuel vapor
containment tank of FIG. 5.
[0020] FIG. 7 is a somewhat diagrammatic representation of the fuel
vapor containment system of FIG. 5 during a fuel drop.
[0021] FIG. 8 is an end view of an underground fuel storage tank
having a fuel inlet pipe terminating in the ullage space.
[0022] FIG. 9 is an end view of another implementation of a fuel
vapor containment system of the disclosure with an underground fuel
vapor containment tank.
[0023] FIG. 10 is a somewhat diagrammatic representation of a
system for generation of electrical power including a
motor/generator set selectively powered by fuel vapor, e.g. from a
fuel vapor containment system of the disclosure, or by liquid
fuel.
[0024] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0025] Referring to FIG. 1, in a typical prior art fuel storage and
delivery system 10, e.g. at a vehicle fueling service station, S,
each underground storage tank 14 contains a volume of volatile
liquid fuel 16, e.g. gasoline, and a volume of a saturated or
semi-saturated mixture of gaseous fuel vapor and/or air 18 in a
vapor or ullage space, U, above the liquid fuel. The ullage space
is connected to the atmosphere via conduit 20, controlled by a UST
pressure/vacuum relief vent valve 22, which typically is set to
open at -8.0 inches W.C. to permit intake of air into the ullage
space and to open at +3.0 inches W.C. to permit release of gaseous
vapor from the ullage space, thereby to avoid dangerous buildup of
pressure or vacuum within the UST 14.
[0026] During refueling of a vehicle, C, as liquid fuel, L, is
delivered via conduit 24 from the UST 14 into the vehicle fuel tank
28, fuel vapor, V, displaced from the vehicle fuel tank by the
liquid fuel is permitted to escape into the environment.
[0027] Bulk liquid fuel is delivered to service station, S, by fuel
delivery vehicle, e.g. tanker truck 30. During a fuel "drop" or
delivery, the truck tank is connected by conduit 32 to the fuel
inlet spout 15 of UST 14, while the ullage space 18 of UST 14 is
connected by conduit 36 to the ullage space 34 of the tanker truck.
Delivery of liquid fuel 16 into UST 14, e.g. about 5,000 gallons
delivered at 400 GPM (gallons per minute) is typical, causes
displacement of fuel vapor 18 from the ullage of space, U, of UST
14, into the ullage space 34 of the tank truck, replacing the
liquid fuel as it is delivered. Upon completion of the fuel drop,
the tanker truck departs carrying 5,000 gallons of fuel vapor
created from gasoline previously purchased by the service station
owner, with the fuel vapor being subsequently displaced back into
fuel company tanks as the tanker truck is filled for its next
delivery.
[0028] Referring now to FIG. 2, according to the present
disclosure, the fuel storage and delivery system 10', e.g. at a
gasoline fueling station, S', is further equipped with vapor
containment system 12 of the disclosure for capturing and retaining
fuel, e.g. gasoline vapors, at a service station, e.g. rather than
transferring the vapors for removal in a fuel tanker truck, as
typically occurs at service stations with Phase I only vapor
recovery, and/or rather than releasing all or a portion of those
fuel vapors into the environment.
[0029] The vapor containment system 12 includes a vapor storage
tank 42, e.g. an 8,000 gallon steel storage tank, connected to
conduit 20, which, in turn, is in communication with the vapor
space, U, of UST 14. The vapor space is controlled by
pressure/vacuum relief vent valve 22, as described above. The
storage tank 42 contains a thin wall, resilient, flexible urethane,
inflatable bladder 44 defining an auxiliary vapor space volume 46
within the bladder, which is in communication with the UST vapor
space, U, via conduit 20. The bladder 44 and the storage tank wall
48 also together define an air space 50 within the vapor storage
tank 42 but external of the bladder 44, which is in communication
with the atmosphere through a 1/8-inch orifice air relief/air
ingestion port 52 to release air from the air space 50, and also to
ingest air into the air space 50 at about 20 GPM when the pressure
differential is 1 inch W.C., as described in more detail below.
This is a passive system not requiring electrical components. As a
result, installation costs are relatively low.
[0030] Referring also to FIGS. 3 and 4, and also to my U.S. Pat.
No. 6,805,173, the complete disclosure of which is incorporated by
reference herein, the vapor storage tank 42 is shown mounted in
vertical position, e.g. upon a concrete tank slab 66. (Other
suitable methods for installation and mounting may be employed.)
The bladder 44 is suspended within the air space volume 50 of the
tank 42 from the bladder support assembly 68. The support assembly
includes a flange 70, secured to neck 71 at an aperture 72 into the
tank volume by bolts 98 with lock washers 100 and nuts 102, sealed
by o-rings 103, from which extends a pipe nipple 74 supporting a
circumferential bladder flange 76. A clamp ring 78 bolted (79) to
the bladder flange secures and seals the bladder opening. A tap 80
defines an inlet/outlet 81 to a first, axial vapor passageway 83
into the bladder volume 46 by way of pipe nipple 82 terminating in
a pipe barb 84 and a siphon tube 85 that extends to the lower end
of the bladder 44 within the tank 42. A tee-fitting 86 (to which
tap 80 is mounted) defines an inlet/outlet 87 to a second, annular
passageway 88 through the space between coupling 90 and pipe nipple
74 and the outer wall of pipe nipple 82. The inlets/outlets 81, 87,
as well as condensate drain 92 from the base of the tank air space
50, are connected to conduit 20 by 1-inch connection piping 94.
Flow through the connection piping 94 is controlled by ball valves
95, which should be padlock-secured against tampering. The air
relief/air ingestion port 52 is connected to a pipe nipple 53 (FIG.
3) mounted to the flange 70 at an aperture 96 in communication with
the air space 50 about the bladder 44 in tank 42.
[0031] In FIGS. 1 and 2, as described above, all three USTs 14 are
employed for storage of liquid fuel, traditionally with the USTs
14, 14' and 14'' respectively dedicated to storage of regular grade
fuel, middle or mid grade fuel, and premium or plus grade fuel.
[0032] Referring also now to FIG. 5, in another, generally more
preferred implementation, fuel storage and delivery system 10'' is
upgraded for use with a Uni-hose dispenser system (not shown) that
permits blending of regular grade fuel with premium or plus grade
fuel from USTs 114 and 114' to provide a blended middle or mid
grade fuel at the dispenser 26 (FIGS. 1 and 2). As a result, the
third UST 114'' is no longer utilized for storage of liquid fuel,
making it available for use as a vapor storage tank 142 in a vapor
containment system 112. The existing third tank, previously used to
hold the mid-grade fuel product, is converted into a fuel vapor
containment tank 142, in a vapor containment system 112, with an
inflatable/collapsible bladder 144 for capturing and containing
fuel vapor disposed within the underground tank. This alternative
implementation typically provides relatively better economics,
since it makes unnecessary installation of an additional
aboveground tank and piping, e.g. as described with respect to FIG.
2.
[0033] According to this implementation, the third UST 114'' is
retrofitted (typically after removal of the submerged turbine fuel
pump (not shown) to provide maximum available volume) by
installation of an inflatable/collapsible bladder 144, e.g., formed
of thin wall, resilient, flexible material, e.g. urethane, defining
an auxiliary vapor space volume 146 through the tank hatchway 130
(FIG. 5). The fuel vapor piping 120 is modified to place the ullage
spaces, U, of USTs 114 and 114' in communication with the auxiliary
vapor space volume 146 of the bladder 144, e.g. via the former
liquid fuel submerged turbine port pipe 115. The fuel vapor outlet
pipe 117 from tank 114'', now in communication with the air space
150 defined between the bladder 144 and the storage tank wall 148,
is placed in communication with the atmosphere through conduit 152,
terminating at an air relief/air ingestion assembly 154, having a
1/8-inch orifice, again as described in more detail below. The
piping connection between tank 114'' and the fuel vapor piping 120
is secured by valve 156, which is closed during normal operation.
As in the implementation described above, this is a passive system
not requiring electrical components. As a result, retrofitting and
installation costs are relatively low.
[0034] Referring also to FIG. 6, and with reference to the above
description of FIGS. 3 and 4, the bladder 144 is suspended within
the air space volume 150 of the tank 142 from the bladder support
assembly 168, through which extends former liquid fuel submerged
turbine port 115, now connected to vapor conduit 120.
[0035] Referring again to FIG. 2, and more particularly to FIG. 7,
in operation of the vapor containment system 112 of the disclosure,
a fuel drop or delivery at a vehicle fueling service station, S',
with conservation of fuel vapor by the fuel station operator or
owner, proceeds as follows:
[0036] 1. With the bladder 144 in a collapsed condition, the driver
of fuel tanker truck 30 makes a fuel hose connection (typically a
4-inch diameter hose 32) between the underground storage tank 114
and the tanker truck 30.
[0037] 2. The driver makes a vapor hose connection (typically a
3-inch diameter hose 36) to the UST vapor connection pipe 119 in
communication with the air space 150 of the vapor containment tank
114'', external of the bladder 144.
[0038] 3. The driver opens the tanker vapor valve 301.
[0039] 4. The driver opens the tanker liquid fuel valve 302.
[0040] 5. The tanker truck 30 drops 5,000 gallons of liquid fuel 16
through conduit 32 and pipe inlet 15, into the UST 114, at a rate
of up to 400 GPM, forcing 5,000 gallons of vapor 18 from the ullage
space, U, of UST 114, through vapor conduit 120 and pipe
inlet/outlet 115, into the auxiliary vapor space volume 146 of the
bladder 144.
[0041] 6. Inflation of the bladder 144 forces 5,000 gallons of air
from the air space 150 between the bladder 144 and the wall 148 of
UST 114'' through pipe inlet/outlet 119 and conduit 36, into the
tanker 30.
[0042] 7. The tanker 30 disconnects, replaces and properly secures
the UST vapor connection sealing cap 118 on vapor connection pipe
119 (FIG. 5), and leaves, carrying 5,000 gallons of air.
[0043] 8. Vehicles, C, are fueled with the 5,000 gallons of liquid
fuel 16 delivered into UST 114, with removal of liquid fuel 16 from
UST 114 drawing vapor 18 from the auxiliary vapor space volume 146
of bladder 144 into the ullage space, U, of UST 114.
[0044] 9. Removal of vapor 18 from the bladder 144 into the ullage
space, U, of UST 114'' causes gradual collapse of bladder, drawing
air through conduit 152 and pipe 117, into the air space region 150
between the bladder 144 and the wall 148 of the UST 114''.
[0045] 10. The entire process is repeated with each subsequent bulk
delivery of liquid fuel 16.
[0046] Delivery of liquid fuel, e.g. gasoline, from the fuel tanker
truck 30, at flow rates up to 400 GPM, into the underground storage
tank 114 forces the fuel vapor 18 in the ullage space, U, of the
underground storage tank 114 to flow through conduit 120, e.g. an
underground 2-inch pipe, to inflate the bladder 144 in the vapor
containment tank, i.e. aboveground tank 42 (FIG. 2) or underground
tank 114'' (FIGS. 5 and 7), thereby forcing air in the space 150
between the bladder 144 and the inside tank wall 148 to flow out,
and through the vapor hose 36 into the fuel tank truck 30.
[0047] The vapor space of the fuel tanker truck 30 is thus filled
with air expelled from the air space 150 about the bladder 144 of
the containment tank 114'', and the fuel vapor 18 displaced from
the ullage space, U, of the underground storage tank 114 is
contained with the bladder 144, remaining under control and
possession of the service station.
[0048] The fuel vapor 18 that remains in the possession of the
service station owner within the bladder 144 will subsequently,
over time, be drawn back into the ullage space, U, of the
underground fuel storage tank 114 as fuel is removed from the tank
114 to fuel customer vehicles, C. The air that would normally be
ingested as the gasoline level in the underground storage 114 tank
drops is now replaced by fuel vapor 18 from the bladder 144,
resulting in essentially no loss of product due to evaporation.
[0049] The fuel vapor containment system (12, FIG. 2; 112, FIG. 5)
may also provide storage capacity for containing and thereby
preventing diurnal breathing losses. These losses occur due to fuel
evaporation, as the fuel storage and delivery system (10', FIG. 2,
10'' FIG. 5) moves to achieve equilibrium at the interface between
liquid fuel 16 and vapor phase fuel 18 in the UST, and due to
emissions related to changes in barometric pressure.
[0050] The potential savings that might be realized from use of a
vapor containment system of the disclosure at a typical non-Phase
II service station are as follows:
Annual Value of Vapor Retained:
TABLE-US-00001 [0051] Assume: Throughput: 100,000 gallons of fuel
per month Gasoline savings rate: 0.15% Retail sales price: $3.00
per gallon Annual Savings due to retained vapor = 100 , 000 .times.
0.0015 .times. 3.00 .times. 12 = $5 , 400 per year ( at 100 , 000
gallons / month throughput ) ##EQU00001##
Diurnal Breathing Loss Savings:
TABLE-US-00002 [0052] Assume: Positive pressure in the UST for 8
hours per day Vapor Growth Rate: 0.5 GPM Gasoline evaporated per
gallon of vapor: 3.0 grams Given: Gasoline: 6 pounds per gallon
Conversion 454 grams per pound Annual loss: (8 hrs/day) (60
mins/hr) (0.5 gpm) (3 gms/gal) (454 gms/lb) (6.0 lbs/gal) (365
days/yr) = 96.5 gallons per year .times. $3 .00 per gallon = $290
per year ##EQU00002## Total Savings: = $5 , 400 + $290 = $5 , 690
per year for each 100 , 000 gallons of throughput per month
##EQU00003## Annual Savings Annual Savings Annual Throughput at
$3.00/gallon at $3.50/gallon 1,200,000 gallons per year $5,690
$6,638 2,400,000 gallons per year $11,380 $13,276 4,800,000 gallons
per year $22,760 $26,552
[0053] Fuel vapor generation and loss can be relatively higher
under certain conditions. For example, referring to FIG. 8, in a
UST 214, fuel inlet pipe 215 terminates in the upper region of the
UST 214, i.e. in the ullage space, U, rather than, as preferred for
minimizing fuel vaporization, in the lower region of the UST, and
preferably below the level of the liquid fuel 16 in UST 214. The
fuel spray 220 dropping through the ullage space, U, sharply
increases the surface area interface of liquid fuel 16 to air/vapor
18 in the ullage space, U, thus increasing the rate of evaporation
of liquid fuel 16 into fuel vapor 18.
[0054] Referring now to FIG. 10, an energy generation system 400 of
the disclosure includes a motor 402 and a generator 404 coupled in
a motor/generator set 406, e.g. a Guardian, Model 5244, available
commercially from Norwall Power Systems, of Lake Havasu City, Ariz.
After modification to employ a tri-fuel carburetor package capable
of using gasoline, natural gas or propane as an energy source, this
unit will provide 16 KW of power at 240 VAC, single phase.
Depending on conditions at the vehicle fueling service station, S
(FIG. 2), as described in more detail below, and/or decision by the
service station operator or manager, the motor 402 is selectively
fueled by gasoline vapor, e.g. from the vapor containment bladder
44 (FIG. 2), and/or by liquid gasoline from a liquid gasoline fuel
source, e.g. from liquid fuel tank 408.
[0055] When the motor 402 is to be operated on liquid fuel from
tank 408, liquid fuel shut-off valve 410 is opened by a signal 411
from the controller 420 (which is discussed in more detail below)
to permit flow of the liquid fuel to carburetor 412, where it is
combined with a flow of air from air inlet 414. The volume flow
rate of air flowing from the inlet to the carburetor is regulated
by air flow control 418, which is also operated by signals 419 from
controller 420. An air filter 416 is preferably disposed in the air
flow conduit, e.g. between the air inlet and the carburetor.
[0056] When the motor 402 is to be operated on fuel vapor from the
vapor containment bladder 44 (and/or from the ullage spaces, U, of
the USTs 14, 14', 14'' (FIG. 2)), the fuel vapor is delivered
through vapor conduit 422, where vapor shut-off and flow control
valve 424 is opened and regulated by signals 425 from the
controller 420 to permit a controlled volume of fuel vapor to flow
toward the motor 402. When fuel vapors are used to power the engine
402, an air/fuel ratio sensor 426 monitors the air/hydrocarbon
mixture and provides electronic signals 427 to the system
controller 420, which in turn controls the vapor shut-off and flow
control valve 422 and/or the air flow control 418 to adjust the
flow of fuel vapor from the bladder 44 and/or the ullage space, U,
mixed with the flow of ambient air from the inlet 414 to produce
the desired fuel and air mixture. A flame arrestor 428 is
preferably provided in the conduit 420, e.g. between shut-off and
flow control valve 422 and the motor 402.
[0057] Operation of the motor 402 of the motor/generator set 406,
fueled either by evaporated fuel vapor from the vapor conservation
bladder 44 and/or from the UST ullage space, U, or by liquid fuel
from tank 408, powers the generator 404 for generation of
electrical power to be delivered by power lines 438 to the vehicle
fueling service station, S, for its operating needs or into the
local utility power grid for compensation or credit for the service
station operator.
[0058] Upon detection of one of the following conditions, the
controller 420 automatically issues a signal 431 to starter and
battery set 430 mounted to motor 402, to actuate (turn on) the
motor/generator set 406 to begin generation of electrical
power:
[0059] 1. When the vapor space pressure in the underground storage
tanks (USTs 14, 14', 14'') and/or in the vapor containment bladder
44 exceeds atmospheric pressure (i.e., +1/4-inch W.C.), as
communicated to the controller 420 by signal 432.
[0060] 2. When a tank truck 30 (FIG. 7) concludes a fuel drop and
the UST vapor connection sealing cap 118 is properly secured to UST
vapor connection pipe 119 (FIG. 5), as communicated to the
controller 420 by signal 434.
[0061] 3. When an electric power failure occurs at the vehicle
fueling service station, S, as communicated to the controller 420
by signal 436.
[0062] The motor/generator set 406 can also be manually started or
stopped by electrical signal 436 to controller 420 transmitted by
the service station operator or manager as needed or as otherwise
dictated. When manually started, the motor may be operated on
gasoline vapor from the vapor containment system 44 when the vapor
space pressure in the underground storage tanks 14, 14', 14'' is
above +1/4-inch W.C., or, when the pressure is below +1/4-inch
W.C., on liquid gasoline from the fuel tank 408 associated with the
motor/generator set 406.
[0063] The motor/generator set 406 automatically deactivates (turns
off) upon detection of, i.e. in response to signals indicating, one
of the following conditions:
[0064] 1. When the vapor space pressure in the ullage space, U, of
the underground storage tanks and the fully collapsed vapor
containment bladder 44 falls below atmospheric pressure (i.e.,
-1/4-inch W.C.).
[0065] 2. When the Phase I vapor connection sealing cap 118 is
removed from the vapor connection pipe 119 (FIG. 5) of the
underground storage tank 114''.
[0066] Operation of the electrical power generation system 400 of
the disclosure will now be described in use with different
generations of vehicle refueling service stations.
Service Stations with No Vapor Recovery:
[0067] When used in service stations without a vapor recovery
system, the electrical power generation system 400 of the
disclosure restricts discharge of fuel vapors to the atmosphere
through fugitive emission leaks by controlling the UST vapor space
pressure if the storage capacity of the bladder 44 at +1/4-inch
W.C. is exceeded. This condition could occur, e.g., if the
barometric pressure were to drop rapidly. It could also occur,
e.g., when the service station is shut down over night, as a result
of continued evaporation of gasoline until equilibrium conditions
occur.
[0068] When a tank truck 30 is actively refueling the service
station, the vapor storage tank 42 (FIG. 2) provides temporary
storage of the vapors displaced by the in-pouring gasoline. The
stored vapor will then provide the fuel needed to run the
motor/generator set 406 to produce electricity for operation of the
service station, or if excess electric power beyond the needs of
the service station is produced, the extra electricity can be
delivered into the electrical power grid for credit from the local
power utility.
Service Station with Phase I Vapor Recovery:
[0069] When used in service stations equipped with a Phase I vapor
recovery system only, the vapor containment system restricts the
transfer of gasoline vapor from the underground storage tank during
a refueling drop by providing temporary storage for these vapors.
In this case, the tank truck 30 will extract only air from the
space 150 surrounding the bladder 144 in the bladder containment
tank 114''. The gasoline saved in the form of vapor was produced
from the gasoline previously purchased by the service station
owner. The owner of the service station then can elect to use the
captured vapors for the generation of electric power using the
energy generation system 400 of the disclosure, or elect to allow
the captured fuel vapor in the bladder to return to the underground
storage tanks as liquid gasoline is dispensed to customers. This
latter choice will prevent the evaporation of liquid gasoline that
ambient air would cause since the vapor flowing back to the UST
will contain sufficient hydrocarbon vapor to maintain an
equilibrium condition without additional evaporation.
[0070] If the service station shuts down at night, and continued
evaporation of gasoline is taking place, and/or barometric pressure
drops causing the bladder to expand fully, the pressure could rise
to +1/4-inch W.C. When this occurs the motor/generator set 406 will
start automatically to control the UST pressure and supply electric
power for private use with excess electric power flowing to the
utility grid for credit. In addition, the motor/generator set 406
is always available for emergency power generation.
Service Station with Phase I and Phase II Vapor Recovery:
[0071] When used in service stations with both Phase I & II
vapor recovery, the electrical power generation system 400 of the
disclosure has all of the advantages described above for service
stations with Phase I only. The motor/generator set 406 in this
application controls the UST vapor space pressure by turning on
when the pressure reaches +1/4-inch W.C. and turning off when the
pressure falls to -1/4-inch W.C., or to a lower negative pressure,
providing it does not exceed the cracking pressure of the vent
valve 22 (FIG. 2) (i.e., -8 inches W.C.).
[0072] In all of the above applications, the service station owner
has two cost advantages for using electrical/power generation
system 400. The gasoline vapor contained by the system can be used
to generate electricity for their private use, or to reduce their
cost for electric power by providing the excess electricity to the
grid for a credit from the electric utility. The second practical
advantage is the standby electric power generation provided
whenever power failure occurs. This feature will allow the service
station to continue to sell gasoline under power blackout
conditions.
[0073] The disclosure offers both environmental and practical
advantages. An environmental advantage is the effective control of
the vapor space pressure in the underground storage tanks of any
service station to minimize the escape of hydrocarbon vapor to the
atmosphere by holding the pressure slightly above or below
atmospheric. Under negative pressure conditions, ambient air will
be drawn into the ullage space through leaks in the underground
storage tanks and vapor piping system. This disclosure thus has
application in service stations equipped with both Phase I and
Phase II vapor recovery, and in service stations having Phase I
only. The disclosure is equally beneficial in service stations in
those countries that do not mandate the use of vapor recovery
systems. The presence of an emergency back-up generator to keep
service stations operating during periods of public power service
interruption has both economic and public safety advantages.
[0074] A number of implementations of the disclosure have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the disclosure. For example, the bladder described above
may have other forms according to the disclosure. For example, the
bladder may alternatively have the form of a resilient wall or a
diaphragm.
[0075] Also, referring to FIG. 6, retrofitting of an existing,
unused UST 114'' is preferred, e.g. as compared to use of an
aboveground tank for the vapor control system, including for
reasons of cost and security. However, service station USTs are
typically protected by a relative thick, reinforced concrete pad
300, making modification of existing below-ground piping difficult
and expensive, and thus preferably kept to a minimum. As result,
where existing piping arrangements make retrofitting difficult or
overly expensive, an aboveground vapor containment system 12, e.g.
as described above with reference to FIG. 2, may be more
viable.
[0076] Also, the submerged turbine pump in a retrofit UST, e.g. UST
114'' in FIG. 6, may be removed to allow room for expansion and
contraction of the inflatable bladder 144 without unnecessary
physical obstruction within the internal volume of the UST.
[0077] Additionally referring to FIG. 9, in some implementations,
including those described above, in particular with respect to the
implementations of FIGS. 5-7, a vapor conduit 120 connecting the
ullage space, U, of UST 314 with the volume 346 of the bladder 344
in vapor containment tank 314'' may further include float check
valve 380, or, in the alternative, float check valve 380', for
protecting the volume 346 of the inflatable bladder 344 from liquid
fuel 16, e.g. in the event of a tank overfill during a fuel drop.
In the alternative arrangement, the positioning of float check
valve 380' permits liquid fuel 316 from the truck overfill to drain
back into the UST 314.
[0078] Also, for vehicle refueling service stations employing Phase
I and Phase II vapor recovery, the vapor containment bladder system
can optionally be omitted, while using the electrical power
generation system 400 to control pressure of evaporated fuel vapor
in the ullage space of the underground storage tanks.
[0079] Accordingly, other implementations are within the scope of
the following claims.
* * * * *