System and method of automatically ending the filling of a gas transport module or other gas transport
Processes and systems are described, which provide important advantages in filling gas storage vessels, such as gas cylinders for the transport of compressed natural gas (CNG). For example, the flow of gas from the fill station may be terminated safely, using an auto-fill shut-off mechanism, without the risk of exceeding vessel pressure ratings and overall reduced risk of operator error. The automatic termination of flow can occur at a preselected pressure that may, for example, be set at a fixed value, or may otherwise be adjusted based on the local temperature at the time of the fill.
1. A process for filling a gas storage vessel, the process comprising:
providing a valve-regulating gas to a pressure-actuated inlet valve, at a valve pressure sufficient to cause a flow of product gas from an upstream end of a fill assembly, through said pressure-actuated inlet valve, and into said gas storage vessel at a downstream end of said fill assembly,
wherein said valve pressure is controlled based on a comparison between an actual pressure and a target storage pressure of said gas storage vessel, said comparison being performed automatically by a valve position controller in fluid communication with both said gas storage vessel and said pressure-actuated inlet valve.
2. The process of claim 1 , wherein said valve-regulating gas is provided, during a filling period, as a valve gas flow at said valve pressure.
3. The process of claim 2 , wherein, when said actual pressure reaches or exceeds said target storage pressure, said filling period is automatically terminated, by an action of said valve position controller, stopping said valve gas flow.
4. A process for filling a gas storage vessel, the process comprising:
providing a valve-regulating gas to a pressure-actuated inlet valve, at a valve pressure sufficient to cause a flow of product gas from an upstream end of a fill assembly, through said pressure-actuated inlet valve, and into said gas storage vessel at a downstream end of said fill assembly,
wherein said valve pressure is controlled based on a comparison between an actual pressure and a target storage pressure of said gas storage vessel, said comparison being performed automatically by a valve position controller in fluid communication with said gas storage vessel, wherein said valve-regulating gas is provided, during a filling period, at said valve pressure without flow.
5. The process of claim 4 , wherein, when said actual pressure reaches or exceeds said target storage pressure, said filling period is automatically terminated, by an action from said valve position controller, venting said valve-regulating gas.
6. The process of claim 1 , wherein said valve-regulating gas is provided to a first, valve gas side of a diaphragm of said pressure-actuated inlet valve, opposite a second, product gas side.
7. A process for filling a gas storage vessel, the process comprising:
providing a valve-regulating gas to a pressure-actuated inlet valve, at a valve pressure sufficient to cause a flow of product gas from an upstream end of a fill assembly, through said pressure-actuated inlet valve, and into said gas storage vessel at a downstream end of said fill assembly,
wherein said valve pressure is controlled based on a comparison between an actual pressure and a target storage pressure of said gas storage vessel, said comparison being performed automatically by a pressure switch in fluid communication with said gas storage vessel, and
wherein, when said actual storage pressure reaches or exceeds said target storage pressure, said pressure switch causes venting of said valve-regulating gas, terminating said filling period.
8. A process for filling a gas storage vessel, the process comprising:
providing a valve-regulating gas from said storage vessel to a pressure-actuated inlet valve, at a valve pressure sufficient to cause a flow of product gas from an upstream end of a fill assembly, through said pressure-actuated inlet valve, and into said gas storage vessel at a downstream end of said fill assembly,
wherein said valve pressure is controlled based on a comparison between an actual pressure and a target storage pressure of said gas storage vessel, said comparison being performed automatically by a valve position controller in fluid communication with said gas storage vessel.
9. The process of claim 8 , wherein said valve position controller remotely regulates said valve pressure.
10. A process for filling a gas storage vessel, the process comprising:
providing a valve-regulating gas from an air supply for pneumatic air brakes to a pressure-actuated inlet valve, at a valve pressure sufficient to cause a flow of product gas from an upstream end of a fill assembly, through said pressure-actuated inlet valve, and into said gas storage vessel at a downstream end of said fill assembly,
wherein said valve pressure is controlled based on a comparison between an actual pressure and a target storage pressure of said gas storage vessel, said comparison being performed automatically by a valve position controller in fluid communication with said gas storage vessel.
11. The process of claim 1 , wherein said product gas is compressed natural gas (CNG).
12. The process of claim 1 , wherein said product gas is provided at said upstream end of said fill assembly, at a supply pressure of greater than about 3000 psig.
13. The process of claim 1 , wherein said valve-regulating gas is provided to said pressure-actuated inlet valve at a valve pressure from about 25 psig to about 150 psig.
14. The process of claim 1 , wherein said gas storage vessel is part of a gas transport module.
15. A system for filling a gas storage vessel, the system comprising:
a fill assembly having upstream and downstream ends,
a connection for said gas storage vessel at said downstream end of said fill assembly,
a pressure-actuated inlet valve separating said upstream end and said downstream end and configured to receive a valve-regulating gas, at a valve pressure sufficient to cause a flow of product gas from said upstream end into said gas storage vessel
a valve position controller configured for fluid communication with both said gas storage vessel and said pressure-actuated inlet valve, and configured to automatically control said valve pressure based a comparison between an actual pressure and a target storage pressure of said gas storage vessel.
16. The system of claim 15 , further comprising separate, first and second ports at said upstream end, for providing product gas at higher and lower pressures, respectively.
17. The system of claim 16 , wherein said pressure actuated inlet valve is configured to cause flow of product gas from said first port only.
18. A gas transport module, comprising
at least one gas storage vessel connected at said downstream end of said fill assembly of the system of claim 15 .
19. A non-transitory computer readable medium having a computer program stored thereon, the computer program including instructions for causing a processor to perform the steps of:
receiving, during a filling period of a gas storage vessel, a signal representative of an actual pressure of said gas storage vessel; and
comparing the actual pressure to a target storage pressure of said gas storage vessel, and, in the case of said actual pressure meeting or exceeding the target storage pressure, transmitting a signal to a valve position controller in fluid communication with a pressure-actuated inlet valve, to depressurize said pressure-actuated inlet valve, which terminates a flow of product gas to said gas storage vessel, at a valve pressure below a valve threshold pressure.
20. The computer readable medium of claim 18 , wherein the target storage pressure is dependent on a measured, ambient temperature.