Patent Application
20090101118
The disclosure generally relates to a method for supplying fuel to a secondary device.
Several methods are available for storing sufficient amounts of fuel for introduction into a fuel cell or a related device. One method requires high pressure vessels at pressures up to 70 MPa. Another method places a gas absorbing material, such as TiCrMn-alloy, within a storage vessel to increase capacity. Another method uses a cryogenic liquid to store liquid fuel at cryogenic temperatures. Another storage option stows increased amounts of fuel within a storage vessel by utilizing high-surface materials such as activated carbons, zeoliths, metal-organic frameworks, or polymers of intrinsic microporosity.
One embodiment of the disclosure includes a process comprising supplying a gaseous fuel from a fuel storage vessel to a secondary device. The fuel storage vessel may include a gas adsorbing material to enhance the storage capacity of the fuel storage vessel.
Another embodiment of the disclosure may include a process allowing the storage vessel to supply fuel to a secondary device at a predetermined feed pressure. When necessary, a gas compressor activates to assist in supplying fuel to the secondary device at the predetermined feed pressure.
Other exemplary embodiments of the disclosure will become apparent from the detailed description. It should be understood that the detailed description and specific examples, while indicating the exemplary embodiments of the disclosure, are intended for illustration purposes only and not intended to limit the scope of the invention.
The disclosure will now be described, by way of example, and not limitation, with reference to the accompanying drawings. The following is a brief description of the drawings.
Referring now to
Fuel is introduced into the storage vessel 12 which houses the gas adsorbing material 14. The gas adsorbing material 14 allows for increased storage capacity of the fuel at moderate operating conditions. The gas adsorbing material's 14 storage capacity can be maximized at higher pressures and lower temperatures. In one embodiment, the fuel storage vessel 12 may be refueled to a high pressure so as to adsorb the most amount of fuel possible. In another embodiment, while defueling, or supplying fuel to a secondary device 18, the pressure in fuel storage vessel 12 may decrease. A decrease in pressure of the fuel storage vessel 12 assists in releasing as much fuel from the gas adsorbing material 14 as possible. For example, in various embodiments, the pressures in fuel storage devices containing gas adsorbing materials may range from up to 100 bars when full and down to 0.3 bars when empty, and up to 25 bars when full and down to 1 bar when empty. In other embodiments, temperatures for a fuel storage vessel containing a gas adsorbing material range from 25K to 200K.
A fuel supply line 16 may be connected to the fuel storage vessel 12 in order to pass fuel from the fuel storage vessel 12 to a secondary device 18. Generally, the secondary device 18 is a type of fuel consuming device such as, but not limited to, a fuel cell or a combustion engine. If the secondary device 18 is a fuel cell or a combustion engine, possible fuels include hydrogen and methane. However, the secondary device 18 may also be another storage container such as a transportation vessel, a filling vessel at a filing station, a personal storage vessel, or the like, in which case possible fuels include any fuel required to transported or delivered in a gaseous state.
In various embodiments, fuel may be supplied to a secondary device 18 at a predetermined feed pressure of about 3 bars or greater, 3 to 7 bars, or 5 bars. One way to supply feed pressure to the secondary device 20 is to utilize the pressure of the fuel storage vessel 12. For example, the fuel storage vessel 12 can provide the necessary feed pressure to deliver fuel to the secondary device 18 when the fuel storage vessel 12 is full or mostly full. However, the pressure in the fuel storage vessel 12 might decrease as fuel is removed and supplied to the secondary device 18. As mentioned above, a decrease in pressure of the fuel storage vessel 12 aids the gas adsorbing material 14 in releasing fuel. Eventually, the pressure in the fuel storage vessel 12 might fall to levels at or below the predetermined feed pressure of the secondary device 18. At that point, the fuel storage vessel 12 might not be able to supply sufficient fuel to the secondary device 18 on its own. Therefore, any remaining fuel stored in the fuel storage vessel 12, which can be significant for vessels containing a gas adsorbing material, will go unused.
In one embodiment, a gas compressor 20 can be utilized to extract additional fuel from the fuel storage vessel 12 and supply it to the secondary device 18 at the predetermined feed pressure. The type of gas compressor used may be any gas compressor known to those of ordinary skill in the art such as, but not limited to, reciprocating compressors, rotary screw compressors, centrifugal compressors, axial-flow compressors, and scroll compressors. The gas compressor 20 may be located in the fuel supply line 16 or in a separate line. The gas compressor 20 allows for the fuel storage device 12 to be operated at a pressure lower than the predetermined feed pressure in order to release additional amounts of fuel from the gas adsorbing material 14.
In an embodiment without a gas compressor 20, the fuel storage vessel 12 might be limited to high operating pressures capable of providing the predetermined feed pressure to the secondary device 18. These high operating pressures are inefficient because the gas adsorbing material 14 can store sufficient amounts of fuel at pressures below the feed pressure of the secondary device 18. Therefore, when limited to high operating pressures, only a portion of the fuel storage vessel's 14 storage capacity is delivered to the secondary device 18 and more frequent refueling may be required.
Referring again to
In another embodiment of the disclosure, the fuel storage vessel 12, with or without the gas compressor 20, may supply fuel to the secondary device 18 at the predetermined feed pressure. The fuel storage vessel 12 includes a gas adsorbing material 14 for enhancing fuel storage capacity. The fuel storage vessel 12 may be refueled to a pressure well above the predetermined feed pressure of the secondary device 18 in order to maximize the storage capacity of the gas adsorbing material 14. The relatively high pressure of the fuel storage vessel 12 delivers fuel to the secondary device 18 by way of the fuel supply line 16. A pressure regulation system may not be necessary if the secondary device 18 can handle the full pressure range of the fuel storage vessel 12. Also, the gas compressor 20 may be inactive during initial operation because the pressure in the fuel storage vessel 12 is sufficient to supply fuel to the secondary device 18 at the predetermined feed pressure. When the pressure in the fuel storage vessel 12 drops to a predetermined level, the gas compressor 20 activates and delivers the fuel to the secondary device 18 at the predetermined feed pressure. For example, in one embodiment, the predetermined level at which the gas compressor 20 activates may be when the pressure in the fuel storage vessel 12 drops to less than 10% above, at, or below the predetermined feed pressure of the secondary device 18. Also, activating the gas compressor 20 and delivering fuel to the secondary device 18 further reduces the pressure in the fuel storage vessel 12, thus releasing additional fuel from the gas adsorbing material 14.
Another embodiment of the disclosure is shown in
Another embodiment of the disclosure is shown in
In one embodiment, the first conduit line 216 includes a second conduit line 224 to assist in delivering fuel at a predetermined feed pressure to the secondary device 218. The gas compressor 220 may be located on the second conduit line 224 and one or more back pressure valves 226 may be located on the first conduit line 216 or the second conduit line 224, or both In this embodiment, one or more back pressure valves 226 may be utilized to keep fuel from flowing in a reverse direction when the gas compressor 220 is activated or not activated. For example, a back pressure valve may be located in the first conduit line 216 to prevent fuel from flowing back towards the fuel storage vessel 212 by way of the first conduit line 216 when the gas compressor 220 is activated and fuel is being delivered to the fuel storage vessel 212 through the second conduit line 224. A back pressure valve may also be located in the second conduit line 224 to prevent fuel from flowing back towards the fuel storage vessel 212 by way of the second conduit line 224 when the gas compressor 220 is not activated and fuel is being delivered to the fuel storage vessel through the first conduit line 224. One or more pressure regulators 222 may be located on the first conduit line 216 to maintain a predetermined feed pressure to the secondary device 218 if the secondary device 218 is not designed to operate at the high pressures of the fuel storage vessel 212 It should be noted that it is possible to switch the location of the one or more pressure regulators 222 with that of the gas compressor 220. This alternative configuration places the one or more pressure regulators 222 on the second conduit line 224 and the gas compressor 220 on the first conduit line 216. It should also be noted that various control configurations known to those or ordinary skill in the art may be used in conjunction with this embodiment to control flow of the fuel through the first conduit line 216 and the second conduit line 224. For example, the first conduit line 216 and the second conduit line 224 may include one or more valves to control the direction of fuel flow through the fuel supplying system 210.
In another embodiment, the first conduit line 216 and the second conduit line 224 may be separate lines to the secondary device 218. The first conduit line 216 may supply fuel to the secondary device 218 when the pressure in the fuel storage vessel is high enough to supply fuel to the secondary device 218 at the predetermined feed pressure. The second conduit line 224 may include a gas compressor 220 that activates when the pressure in the fuel storage vessel 212 falls to a predetermined level. The first conduit line 216 and the second conduit line 224 may contain one or more pressure regulators 222 to maintain a predetermined feed pressure to the secondary device if the secondary device is not designed to operate at the high pressures of the fuel storage vessel 212. The first conduit line 216 and the second conduit line 224 may also include back pressure valves 226 to keep fuel from flowing back towards the fuel storage vessel. Furthermore, various control configurations known to those or ordinary skill in the art may be used in conjunction with this embodiment to control flow of the fuel through the first conduit line 216 and the second conduit line 224.
Still referring to
While exemplary embodiments of the disclosure have been described above, it will be recognized and understood that various modifications can be made by those of ordinary skill in the art. The appended claims are intended to cover all such modifications which may fall within the spirit and scope of the invention.
