Fluent material handling – with receiver or receiver coacting mea – Multiple passage filling means for diverse materials or flows – With baffle – spreader – displacer – drip ring – filter or screen
Reexamination Certificate
2002-12-09
2004-06-01
Jacyna, J. Casimer (Department: 3751)
Fluent material handling, with receiver or receiver coacting mea
Multiple passage filling means for diverse materials or flows
With baffle, spreader, displacer, drip ring, filter or screen
C141S003000, C141S004000, C141S018000, C141S325000, C222S003000, C222S131000, C137S264000, C220S560050, C220S560070, C220S560100, C220S560110, C220S565000
Reexamination Certificate
active
06742554
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a type 4 compressed gas container and, more particularly, to a type 4 compressed gas container for storing hydrogen gas on a vehicle for a fuel cell engine, where the container includes an inner vessel for preventing heated gas from damaging an internal liner of the container while the container is being filled with compressed gas.
2. Discussion of the Related Art
Hydrogen is a very attractive source of fuel because it is clean and can be used to efficiently produce electricity in a fuel cell. The automotive industry expends significant resources in the development of hydrogen fuel cells as a source of power for vehicles. Such vehicles would be more efficient and generate fewer emissions than today's vehicles employing internal combustion engines.
A hydrogen fuel cell is an electrochemical device that includes an anode and a cathode with an electrolyte therebetween. The anode receives hydrogen gas and the cathode receives oxygen. The hydrogen gas is ionized in the anode to generate free hydrogen ions and electrons. The hydrogen ions pass through the electrolyte to the cathode. The hydrogen ions react with the oxygen and the electrons in the cathode to generate water as a by-product. The electrons from the anode cannot pass through the electrolyte, and thus are directed through a load to perform work before being sent to the cathode. The work acts to operate the vehicle. Many fuels cells are combined in a stack to generate the desired power.
A vehicle fuel cell engine can include a processor that converts a liquid fuel, such as alcohols (methanol or ethanol), hydrocarbons (gasoline), and/or mixtures thereof, such as blends of ethanol/methanol and gasoline, to hydrogen gas for the fuel cell. Such liquid fuels are easy to store on the vehicle. Further, there is a nationwide infrastructure for supplying liquid fuels. Gaseous hydrocarbons, such as methane, propane, natural gas, LPG, etc., are also suitable fuels for both vehicle and non-vehicle fuel cell applications. Various processors are known in the art for converting the liquid fuel to gaseous hydrogen suitable for the fuel cell.
Alternatively, hydrogen gas can be processed separate from the vehicle and stored at filling stations and the like. The hydrogen gas is transferred from the filling station to pressurized tanks or containers on the vehicle to supply the desired hydrogen gas to the fuel cell engine as needed. Typical pressures within compressed hydrogen gas containers for fuel cell applications are in the range of 200 bar-700 bar.
Storage containers for compressed gases must have mechanical stability and integrity so that the container does not rupture or burst from the pressure within. It is typically desirable to make hydrogen gas containers on vehicles lightweight so as not to significantly affect the weight requirements of the vehicle. The current trend in the industry is to employ type 4 compressed gas tanks for storing compressed hydrogen gas on the vehicle. A type 4 tank includes an outer structural layer made of a synthetic material, such as a glass fiber or a carbon fiber wrap, and a plastic liner. The outer layer provides the structural integrity of the tank for the pressure contained therein, and the plastic liner provides a gas tight vessel for sealing the gas therein. The plastic liner is first formed by a molding process. Then, the fiber wrap is formed around the liner and caused to set thereto.
FIG. 1
is a cross-sectional view of a type 4 compressed gas container
10
currently contemplated in the industry to store compressed hydrogen gas on a vehicle for fuel cell engines. The container
10
is cylindrical in shape to provide the desired integrity, and includes an outer structural wall
12
and an inner liner
14
defining a container chamber
16
therein. The outer wall
12
is typically made of a suitable fibrous interconnected synthetic wrap, such as glass or carbon fiber wraps, and has a sufficient thickness to provide the desired mechanical rigidity for pressure containment. The liner
14
is typically made of a suitable plastic, such as a high-density polyethylene, to provide a gas tight containment vessel within the container
10
. The thickness of the liner
14
is generally about 5 mm. Thus, the combination of the outer wall
12
and the liner
14
provides the desired structural integrity, pressure containment and gas tightness in a light-weight and cost effective manner.
The container
10
includes an adapter
18
that provides the inlet and outlet opening for the hydrogen gas contained therein. The adaptor
18
is typically a steel structure that houses the various valves, pressure regulators, piping connectors, excess flow limiter, etc. that allow the container
10
to be filled with the compressed hydrogen gas, and allow the compressed gas to be discharged from the container
10
at or near ambient pressure, or a higher pressure, to be sent to the fuel cell engine. The adapter
18
is made of steel to provide the structure desired for storing compressed hydrogen gas, and typically has a weight of about 5 kg. A suitable adhesive, sealing ring, or the like is employed to seal the liner
14
to the adapter
18
in a gas tight manner, and secure the adapter
18
to the outer wall
12
.
FIG. 1
shows the container
10
being filled with a hydrogen fill gas
20
through the adaptor
18
. During the filling process, the fill gas.
20
flows into the container
10
from one end
22
of the container
10
to an opposite end
24
of the container
10
and becomes contained gas
26
. As the filling process proceeds, the pressure in the container
10
increases. It is desirable that the temperature of the fill gas
20
be near ambient temperature (300 K, 27° C.) and be at a suitable pressure to fill the container
10
within a few minutes (less than three minutes). However, as a result of the thermodynamic properties of the fill gas
20
and the contained gas
26
, adiabatic compression causes the contained gas
26
to be heated in response to the fill gas
20
being introduced therein under pressure.
This heating of the contained gas
26
within the container
10
presents a problem because the plastic liner
14
will be damaged if the temperature of the contained gas
26
increases above a fail temperature of the liner material, for example, above 85° C. If the temperature of the contained gas
26
exceeds the fail temperature of the liner material, the liner material properties will change (melt), and the gas sealing ability of the liner
14
may be compromised. Therefore, it is necessary to provide some technique for maintaining the temperature of the contained gas
26
within the container
10
below the liner fail temperature while the container
10
is being filled and thereafter.
FIGS. 2-4
depict simulations of the contained gas
26
being heated within the container
10
.
FIG. 2
is a plan view of a simulation model
28
where a container
30
is being filled with compressed gas
42
from an infinite reservoir
32
through a valve
34
depicting the Joule Thompson effect. The container
30
is separated into individual cells
36
, here fifty cells, numbered from a first cell
38
closest to the fill point of the container
30
to a last cell
40
at an opposite end of the container
30
from the fill location. Before the filling process is initiated, each of the cells
36
is at a pressure 2.8 MPa and a temperature near ambient, about 300 K. Further, the temperature of the fill gas is also near ambient.
In this simulation, certain assumptions are made that are not present in real applications. First, there is no heat exchange between the contained gas and the container walls or other parts of the container, such as the adapter
18
. Second, the reservoir
32
is infinitely large and therefore no pressure or temperature change occurs in the reservoir
32
during the filling process. Third, the fill gas is introduced in a longitudinal direction into the container
30
from left to right. Fourth, t
Brooks Cary W.
Jacyna J. Casimer
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