Claims
- 1. A storage system for storing a compressible gas in the dense phase under pressure, the storage system comprising:one or more pipes of a material which will withstand a predetermined range of temperatures and meet required design factors for the pipe material; a chilling member cooling the gas to a temperature within said temperature range; a pressurizing member pressurizing the gas within a predetermined range of pressures at a lower temperature of said temperature range where the compressibility factor of the gas is at a minimum; and said chilling member and pressurizing member setting the temperature and pressure of the gas to maximize the ratio of mass of stored gas to mass of the pipe.
- 2. The storage system of claim 1 wherein said pipes material is either X-80 or X-60 premium high strength steel and said temperature range is between −20° F. and 0° F.
- 3. The storage system of claim 2 wherein said lower temperature is substantially −20° F.
- 4. The storage system of claim 3 wherein the gas has a specific gravity of about 0.6 and said pressure range is between 1800 and 1900 pounds per square inch.
- 5. The storage system of claim 3 wherein the gas has a specific gravity of about 0.7 and said pressure range is between 1300 and 1400 pounds per square inch.
- 6. The storage system of claim 1 wherein said pipe is made of X-100 premium high strength steel and said temperature range is between −40° F. and 0° F.
- 7. The storage system of claim 4 wherein said lower temperature is substantially −40° F.
- 8. The storage system of claim 1 wherein said pressure range is that range of pressures at said lower temperature where the compressibility factor varies no more than 2% of the minimum compressibility factor.
- 9. The storage system of claim 1 wherein there are a plurality of pipes connected by one or more manifolds.
- 10. The storage system of claim 1 wherein the pipe material is steel and one required design factor is 0.5 of the yield strength of steel pipe.
- 11. The storage system of claim 1 wherein said pipe is made of steel and further including maximizing the ratio of the mass of the stored gas to the mass of said steel pipe.
- 12. The storage system of claim 11 wherein the pipe diameter and pipe wall thickness are chosen to maximize the ratio of masses.
- 13. The storage system of claim 12 wherein the gas has a specific gravity of substantially 0.6 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 20 inches, and the pipe wall thickness is between 0.43 and 0.44 inches.
- 14. The storage system of claim 12 wherein the gas has a specific gravity of substantially 0.6 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 36 inches and the pipe wall thickness is between 0.78 and 0.79 inches.
- 15. The storage system of claim 12 wherein the gas has a specific gravity of substantially 0.7 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 24 inches and the pipe wall thickness is between 0.38 and 0.39 inches.
- 16. The storage system of claim 12 wherein the gas has a specific gravity of substantially 0.7 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 36 inches and the pipe wall thickness is between 0.58 and 0.59 inches.
- 17. A method for storing a compressible gas in the dense phase in a storage container under pressure, the method comprising:selecting a predetermined range of temperatures which meet the required design factors for the storage container; selecting a predetermined range of pressures at a lower temperature of said temperature range which minimizes the compressibility factor of the gas; and maximizing the mass of gas to mass of container ratio.
- 18. The method of claim 17 wherein said storage container is made of X-80 or X-60 premium high strength steel and said temperature range is between −20° F. and 0° F.
- 19. The method of claim 18 wherein said lower temperature is substantially −20° F.
- 20. The method of claim 19 wherein the gas has a specific gravity of about 0.6 and said pressure range is between 1800 and 1900 pounds per square inch.
- 21. The method of claim 19 wherein the gas has a specific gravity of about 0.7 and said pressure range is between 1300 and 1400 pounds per square inch.
- 22. The method of claim 17 wherein said storage container is made of X-100 premium high strength steel and said temperature range is between −40° F. and 0° F.
- 23. The method of claim 22 wherein said lower temperature is substantially −40° F.
- 24. The method of claim 17 wherein said pressure range is that range of pressures at said lower temperature where the compressibility factor varies no more than 2% of the minimum compressibility factor.
- 25. The method of claim 17 wherein said storage container is made of steel pipe.
- 26. The method of claim 25 wherein one required design factor is 0.5 of the yield strength of the steel pipe.
- 27. The method of claim 25 further including maximizing the ratio of the mass of the stored gas to the mass of the steel pipe.
- 28. The method of claim 27 further including selecting a pipe diameter and determining the optimum pipe wall thickness from the ratio of masses.
- 29. The method of claim 28 wherein the gas has a specific gravity of substantially 0.6 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 20 inches and the pipe wall thickness is between 0.43 and 0.44 inches.
- 30. The method of claim 28 wherein the gas has a specific gravity of substantially 0.6 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 36 inches and the pipe wall thickness is between 0.78 and 0.79 inches.
- 31. The method of claim 28 wherein the gas has a specific gravity of substantially 0.7 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 24 inches and the pipe wall thickness is between 0.38 and 0.39 inches.
- 32. The method of claim 28 wherein the gas has a specific gravity of substantially 0.7 and wherein one required design factor is 0.5 of the yield strength of the steel pipe, the steel pipe has a yield strength of 80,000 psi, the pipe diameter is 36 inches and the pipe wall thickness is between 0.58 and 0.59 inches.
- 33. A method for optimizing gas payload in a gas storage pipe, the method comprising:selecting a pipe having a yield strength; selecting the minimum temperature which will allow the pipe material to meet a predetermined design consideration; determining the pressure, as controlled by a design factor, that at the minimum temperature, locally maximizes the mass of the gas in the pipe; maximizing the ratio of the mass of the stored gas to the mass of the pipe; selecting a pipe diameter; and determining the optimum pipe wall thickness from the ratio of masses and selected pipe diameter.
- 34. The method of claim 33 wherein the steel pipe is a high strength steel pipe 36 inches in diameter and made of material having a yield strength between 60,000 and 100,000 pounds per square inch.
- 35. The method of claim 33 wherein the design factor is the lower of 0.5 of the yield strength of the pipe and 0.33 of the ultimate tensile strength of the pipe.
- 36. The method of claim 33 wherein the minimum temperature is −20° F.
- 37. The method of claim 36 wherein the optimum pressure is between 1,200 and 1,500 pounds per square inch.
- 38. The method of claim 37 wherein the steel pipe has a 36 inch diameter.
- 39. The method of claim 38 wherein the gas has a specific gravity of 0.6 and the pipe has a wall thickness of 0.66 inches.
- 40. The method of claim 38 wherein the gas has a specific gravity of 0.7 and the pipe has a wall thickness of 0.49 inches.
- 41. The method of claim 33 wherein the ratio of the mass of stored gas to the mass of storage components is at least 0.3.
- 42. A system for storing gas having a compressibility factor and a gas constant, the system comprising:a plurality of pipes having an inner and outer diameter; a manifold connecting said plurality of pipes; and said pipes being made of a material having a yield stress which will withstand a reduced temperature and elevated pressure that maintains the gas at a minimum compressibility factor and in a dense phase, wherein said pipe material and the reduced temperature and elevated pressure are chosen so as to maximize the value of Ψ as determined by: Ψ=S2 ρsZRTg Di(Do+Di);where S is the allowable stress of the pipe material, ρs is the density of the pipe material, Z is the compressibility factor of the gas, R is the gas constant, Tg is the reduced temperature; Di is the inner diameter of the pipe, and Do is the outer diameter of the pipe.
- 43. The system of claim 42 wherein the gas is stored at a temperature in the range of −20° F. to 0° F. and at a pressure above 1200 pounds per square inch.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefit of 35 U.S.C. 119(e) of provisional application Ser. No. 60/230,099, filed Sep. 5, 2000 and entitled “Methods and Apparatus for Transporting CNG,” hereby incorporated herein by reference, and is related to U.S. patent application entitled “Methods and Apparatus for Compressible Gas”, filed concurrently herewith and hereby incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
US Referenced Citations (43)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1073399 |
Mar 1911 |
CA |
Non-Patent Literature Citations (3)
Entry |
D. Stenning: The Coselle CNG Carrier A New Way to Shop Natural Gas by Sea[online] [Retrieved on Jun. 21, 2000] Retrieved from the Internet:<URL: http://www.coselle,com/tech.htm:. |
D. Stenning: The Coselle CNG Carrier A New Way to Shop Natural Gas by Sea[online] [Retrieved on Jun. 21, 2000] Retrieved from the Internet:<URL: http://www.coselle,com/tech.htm: http://www.coselle,com/tech2.htm; http://www.coselle.com/tech3.htm; http://www.coselle.com/tech4.htm; and http://www.coselle.com/tech5.htm. |
PCT International Search Report for Appln. No. PCT/US01/27470, Dated Jun. 26, 2002; (5 p.). |
Provisional Applications (1)
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Number |
Date |
Country |
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60/230099 |
Sep 2000 |
US |