Reciprocating compressor with high pressure storage vessel let down for CNG station and refueling motor vehicles

• US 8,950,441 B2
• Filed: 06/01/2011
• Issued: 02/10/2015
• Est. Priority Date: 06/10/2010
• Status: Active Grant

• Current Assignee: Clean Energy Fuels Corp.
• Original Assignee: Clean Energy Fuels Corp.
• Inventors: Ding, Denis, Pratt, Mitchell
• Primary Examiner(s): Maust, Timothy L
• Assistant Examiner(s): KELLY, TIMOTHY PATRICK
• Application Number:
  US13/151,072
• Publication Number:
  US 20110303323A1
• Time in Patent Office: 1,350 Days
• Field of Search: 141/1, 141/4, 141/11, 141/82, 141 94- 95, 141/197
• US Class Current: 141/4
• CPC Class Codes: B65B 1/20 Reducing volume of filled material
• 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 2223/036 Very high pressure (>80 bar)
• CPC Class Codes: F17C 2225/0123 gaseous, e.g. CNG, GNC
• CPC Class Codes: F17C 2225/036 Very high pressure, i.e. above 80 bars
• CPC Class Codes: F17C 2227/0164 with specified compressor type, e.g. piston or impulsive type
• CPC Class Codes: F17C 2227/0185 comprising several pumps or compressors
• CPC Class Codes: F17C 2250/0626 Pressure
• CPC Class Codes: F17C 2265/065 for refuelling vehicle fuel tanks
• CPC Class Codes: F17C 2270/0178 Cars
• CPC Class Codes: F17C 5/06 for filling with compressed gases

Abstract

Embodiments of the present invention are directed toward a reciprocating compressor having a high pressure storage vessel let down for a CNG station for refueling motor vehicles, wherein the CNG station design utilizes inlet gas from a local gas utility. By supplementing the inlet gas with a pressure let down in order to de-pressurize the gas from a high-pressure storage vessel, the CNG station has the ability to increase and adjust its flow capacity.

Claims

1. A system, comprising:

a gas inlet section including an inlet gas meter for metering inlet gas from a high pressure storage vessel;

a compressor section;

a valve control panel and storage section;

a pressure let down section comprising multi-stage depressurization regulators, pressure transducers, and gauges to monitor its operation, wherein the pressure let down section depressurizes the high pressure gas from the high pressure storage vessel to the inlet of the compressor section, thereby increasing the flow capacity of the system and providing the ability to increase and adjust its flow capacity; and

a dispensing section.

2. The system of claim 1, wherein the system utilizes inlet gas from a local gas utility.

3. The system of claim 1, wherein the gas inlet section is provided and delivered to the site location by a local gas utility.

4. The system of claim 1, wherein the compressor section comprises a single high pressure reciprocating compressor.

5. The system of claim 4, wherein the high pressure compressor comprises a rotary, single-screw, positive-displacement compressor including a drive shaft, a main screw having six helical grooves, and two planar gaterotors.

6. The system of claim 1, wherein the compressor section comprises a combination of multiple reciprocating compressors configured in parallel.

7. The system of claim 1, wherein the valve control panel and storage section comprises a series of control valves that direct the flow of gas from the compressor to either local storage vessels or to the dispensing section.

8. The system of claim 1, wherein the dispensing section comprises one or more dispensers selected from the group consisting of fast fill dispensers and time fill dispensers.

9. The system of claim 1, wherein the pressure let down section is capable of drawing the gas from the high pressure vessel at a pressure from 3600 psig to 4500 psig down to a pressure of 20 psig to 200 psig before it enters the compressor section.

10. The system of claim 1, wherein the pressure let down section allows the compressor to operate at a high flow capacity during peak hours, and wherein the pressure let down section allows the reciprocating compressor to draw in gas from the local gas utility and refill the high pressure storage vessels at a slower flow capacity and at a lower power level during non-peak hours.

11. The system of claim 10, wherein the ability to provide higher flow during peak hours and slower flow during non-peak hours provides the system with the ability to actively manage the gas supply and demand levels and control the power draw requirement of the system.

12. A method for refueling motor vehicles using a system having a high pressure storage vessel let down for a CNG station, the method comprising:

metering inlet gas from a high pressure storage vessel;

depressurizing high pressure gas from the high pressure storage vessel to an inlet of a compressor using a pressure let down comprising multi-stage depressurization regulators, pressure transducers, and gauges to monitor its operation, thereby increasing the flow capacity of the CNG station and providing the ability to increase and adjust its flow capacity; and

dispensing the gas.

13. The method of claim 12, wherein the CNG station design utilizes inlet gas from a local gas utility.

14. The method of claim 12, wherein a gas inlet section for metering inlet gas from the high pressure storage vessel is provided and delivered to the site location by a local gas utility.

15. The method of claim 12, wherein the compressor comprises a single high pressure reciprocating compressor.

16. The method of claim 15, wherein the high pressure compressor comprises a rotary, single-screw, positive-displacement compressor including a drive shaft, a main screw having six helical grooves, and two planar gaterotors.

17. The method of claim 12, wherein the compressor comprises a combination of multiple reciprocating compressors configured in parallel.

18. The method of claim 12, further comprising directing the flow of gas from the compressor to either local storage vessels or to a dispensing section for dispensing the gas.

19. The method of claim 12, wherein depressurizing high pressure gas is performed by a pressure let down section that draws the gas from the high pressure vessel at a pressure from 3600 psig to 4500 psig down to a pressure of 20 psig to 200 psig before it enters the compressor section.

20. The method of claim 19, wherein the pressure let down section allows the compressor to operate at a high flow capacity during peak hours, and wherein the pressure let down section allows the compressor to draw in gas from the local gas utility and refill the high pressure storage vessels at a slower flow capacity and at a lower power level during non-peak hours.

21. The method of claim 20, wherein the ability to provide higher flow during peak hours and slower flow during non-peak hours provides the CNG station with the ability to actively manage the gas supply and demand levels and control the power draw requirement of the CNG station.