CNG time fill system and method with safe fill technology

• US 8,783,307 B2
• Filed: 12/29/2010
• Issued: 07/22/2014
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: Clean Energy Fuels Corp.
• Original Assignee: Clean Energy Fuels Corp.
• Inventors: Ding, Denis
• Primary Examiner(s): MAUST, TIMOTHY LEWIS
• Application Number:
  US12/981,276
• Publication Number:
  US 20110155278A1
• Time in Patent Office: 1,301 Days
• Field of Search: 141/4, 141/18, 141/39, 141/47, 141/83, 141/94, 141/95, 141/197, 114/4, 137/110
• US Class Current: 141/197
• CPC Class Codes: F17C 2205/0326 electrically actuated
• CPC Class Codes: F17C 2221/033 Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• CPC Class Codes: F17C 2223/0123 gaseous, e.g. CNG, GNC
• CPC Class Codes: F17C 2227/0157 Compressors
• CPC Class Codes: F17C 2227/0185 comprising several pumps or compressors
• CPC Class Codes: F17C 2250/043 Pressure
• CPC Class Codes: F17C 2250/0473 Time or time periods
• CPC Class Codes: F17C 2250/0626 Pressure
• CPC Class Codes: F17C 2250/0636 Flow or movement of content
• CPC Class Codes: F17C 2260/038 Detecting leaked fluid
• CPC Class Codes: F17C 2265/065 for refueling vehicle fuel tanks
• CPC Class Codes: F17C 2270/0139 Fuel stations
• CPC Class Codes: F17C 5/007 for individual gas tanks or containers, e.g. in vehicles filling with liquid fuel not under pressure, B60S5/02, B67D7/00
• CPC Class Codes: F17C 5/06 for filling with compressed gases

Abstract

The present invention provides a CNG time fill system having a compression system including a gas dryer and one or more gas compressors, a gas storage system for storing the natural gas, a manifold time fill system for filling a plurality of natural gas vehicles with the natural gas, a pressure transducer or pressure transmitter for detecting the pressure within the manifold time fill system, and an automatic shut off valve for selectively stopping the flow of gas into the manifold time fill system.

Claims

1. A compressed natural gas (CNG) time fill system, comprising:

a compression system including a gas dryer and one or more gas compressors;

a gas storage system for storing CNG;

a manifold time fill system for filling a plurality of natural gas vehicles with CNG;

a pressure transducer or pressure transmitter for periodically detecting the pressure within the manifold time fill system to check for steady static pressure within the manifold time fill system during the flow of CNG through the manifold time fill system; and

an automatic shut off valve for selectively stopping the flow of CNG into the manifold time fill system allowing the compression system to fill the gas storage system after a predetermined time and shutting the compression system down when the manifold time fill system fails to achieve the steady static pressure within a predetermined time, while repeatedly allowing the compression system to continue to deliver CNG to the manifold time fill system as long as the manifold time fill system achieves the predetermined steady state level within the predetermined time until the pressure within the manifold time fill system has reached a target fill pressure.

2. The CNG time fill system of claim 1, wherein an amount of storage capacity in the gas storage system is variable based upon compression capacity and number of vehicles.

3. The CNG time fill system of claim 1, wherein the automatic shut off valve isolates the manifold time fill system from the compression system.

4. The CNG time fill system of claim 1, wherein the pressure transducer or pressure transmitter detects a pressure measurement downstream of the automatic shut off valve.

5. The CNG time fill system of claim 4, wherein the pressure measurement is provided to a programmable logic controller.

6. The CNG time fill system of claim 5, wherein the programmable logic controller determines whether the manifold time fill system is maintaining the steady static pressure.

7. The CNG time fill system of claim 6, wherein if the manifold time fill system fails to achieve the steady static pressure within the predetermined time, a system operator is warned of a potential leak.

8. A method for providing a compressed natural gas (CNG) time fill system for simultaneously fueling a plurality of natural gas vehicles, comprising:

charging a gas storage system such that it is ready for fueling;

opening a time fill valve, turning on a compression system and starting to deliver CNG to a manifold time fill system;

closing the time fill valve and allowing the compression system to continue to fill the gas storage system;

waiting for the manifold time fill system to reach a predetermined steady static pressure;

shutting down the compression system and warning a system operator of a potential leak if pressure within the manifold time fill system fails to achieve the predetermined steady static pressure within a predetermined continuous period of time; and

continuing to deliver CNG to the manifold time fill system until the pressure within the manifold time fill system has reached a target fill pressure if the predetermined steady static pressure has been achieved for the predetermined continuous period of time.

9. The method of claim 8, wherein CNG is delivered to the manifold time fill system for a predetermined duration.

10. The method of claim 9, wherein the predetermined duration is based on a number of natural gas vehicles to be fueled, gas storage capacity, and compression capacity.

11. The method of claim 9, wherein the predetermined duration is between 5 minutes and 60 minutes.

12. The method of claim 8, wherein warning the system operator of a potential leak comprises sending an alarm to the system operator.

13. The method of claim 8, further comprising periodically checking and verifying that the manifold time fill system is maintaining a steady state static pressure throughout the entire time fill process.

14. A compressed natural gas (CNG) time fill system, comprising:

a compression system including a gas dryer and one or more gas compressors;

a gas storage system for storing CNG;

a manifold time fill system for filling a plurality of natural gas vehicles with the CNG;

an automatic shut off valve for selectively stopping the flow of CNG into the manifold time fill system by isolating the manifold time fill system from the compression system and allowing the compression system to fill the gas storage system after a predetermined time and shutting the compression system down when the manifold time fill system fails to achieve the steady static pressure within the predetermined time, while repeatedly allowing the compression system to continue to deliver CNG to the manifold time fill system as long as the manifold time fill system achieves the predetermined steady state level within the predetermined time until the pressure within the manifold time fill system has reached a target fill pressure; and

a pressure transducer or pressure transmitter for periodically detecting the pressure within the manifold time fill system downstream of the automatic shut off valve to check for the steady static pressure within the manifold time fill system during the flow of CNG through the manifold time fill system.

15. The CNG time fill system of claim 14, wherein an amount of storage capacity in the gas storage system is variable based upon compression capacity and number of vehicles.

16. The CNG time fill system of claim 14, wherein the pressure measurement is provided to a programmable logic controller.

17. The CNG time fill system of claim 16, wherein the programmable logic controller determines whether the manifold time fill system is maintaining the steady static pressure.

18. The CNG time fill system of claim 17, wherein if the manifold time fill system fails to achieve the steady static pressure within the predetermined time, a system operator is warned of a potential leak.