Patent EA-001951-B1 (EA)
Title: Gas storage method and product
Inventor: MORRIS IAN
IPC: C10L3/06
Filed: 1998-04-16
Abstract: 1. A method of storing natural gas, which comprises (a) admixing the natural gas with one or more hydrocarbons selected from the group of saturated and unsaturated C2- and C3- hydrocarbons, to form a resulting mixture, the amount of said one or more hydrocarbons being sufficient so that the product of the z factor and the molecular weight of the resulting mixture is lower than the product of the z factor and the molecular weight for natural gas alone at the pressure at which the mixture will be stored, and (b) storing said resulting mixture at a temperature not exceeding 110 degree F (38 degree C) and a pressure or at least 1000 psia (6894 kPa). 2. A method as claimed in claim 1, where the hydrocarbon comprises one or more C2- hydrocarbons, in an amount which depends on the pressure at which the storage takes place, said amount being sufficient to give the mixture a total C2- hydrocarbon content which ranges smoothly from a minimum percentage by volume of not less than 26% when the storage is at a pressure of 1000 psia (6894 kPa) to a minimum percentage is about 15% when the pressure is 2200 psia (15168 kPa). 3. A method as claimed in claim 1 or 2, in which the hydrocarbon is ethane. 4. A method as claimed in claim 1, where the hydrocarbon is one or more C3- hydrocarbons in an amount which depends on the pressure at which the storage takes place, said amount being sufficient to give the mixture a total C3- hydrocarbon content which ranges smoothly from a minimum percentage by volume of not less than about 5% when the storage is at a pressure of 1000 psia (6894 kPa) to a minimum percentage of about 5% when the pressure is 2200 psia (15168 kPa). 5. A method as claimed in claims 1 or 4, in which the hydrocarbon is propane or a mixture of propane and etane. 6. A method as claimed in any of claims 1-5, in which the hydrocarbon is present in insufficient quantity for the formation of a liquid phase at the temperature and pressure of storage. 7. A method of storing or transporting natural gas, which comprises: (a) admixing the natural gas with at least one compound selected from the group of ammonia, carbon monoxide and hydrogen fluoride to form a resulting mixture, and (b) storing said resulting mixture or transmitting it by pipeline at a temperature not exceeding 110 degree F (38 degree C) and a pressure of at least 800 psia (5515 kPa). 8. A method as claimed in claim 7, in which the resulting mixture is stored, and said compound is present in an amount of at least 0.5% by volume, but an amount insufficient to form a liquid phase at the temperature and pressure of storage. 9. A method as claimed in claim 7, in which the resulting mixture is transmitted by pipeline, and said compound is present in an amount of at least 4% by volume, but an amount insufficient to form a liquid phase at the temperature and pressure of such transmission. 10. A method as claimed in either of claims 8 or 9, in which said compound is ammonia. 11. A method as claimed in either of claims 8 or 9, in which said compound is hydrogen fluoride. 12. A method as claimed in either of claims 8 or 9, in which said compound is carbon monoxide. 13. A gas mixture, for use in a storage facility at a pressure greater than 1,000 psia (6894 kPa) and a temperature of from -40 degree F. to +120 degree F (from -40 to 49 degree C), which comprises: (a) from 68 to 92% by volume of methane (b) from 6 to 35% by volume of ethane (c) from 0% to 12% by volume of propane (d) from 0% to 1% by volume of butane (e) from 0% to 1% by volume of carbon dioxide (f) from 0% to 2% by volume of nitrogen the total being 100%, and such mixture being completely gaseous with no liquid phase at the temperature and pressure of intended operation. 14. A gas mixture as claimed in claim 13, said gas mixture being at a pressure of 1150-2160 psia (7928-14893 kPa) and a temperature of from -20 degree F. to +120 degree F (from -29 to 49 degree C). 15. A gas mixture as claimed in claim 13, said gas mixture being at a pressure of 1350-1750 psia (9308-12066 kPa) and a temperature of from 35 degree F to +120 degree F. 16. A gas mixture for use in a pipeline or storage at a pressure greater than 800 psia (5515 kPa) and a temperature of from -40 degree F, to +100 degree F (from -40 degree C to 38 degree C), which comprises: (a) natural gas (b) from 0.5% to 10% by volume of ammonia (c) 0 to 3 5% by volume of ethane in addition to the ethane forming part of the natural gas, the total being 100%, and such mixture being completely gaseous with no liquid phase at the temperature and pressure of intended operation. 17. A gas mixture as claimed in claim 16, in which the amount of ammonia present is at least 4% by volume. 18. A gas mixture, for use in a pipeline or storage facility at a pressure greater than 1,000 psia (6894 kPa) and a temperature of -40 degree F. to +100 degree F (from -40 degree C to 38 degree C), which comprises: (a) from 68 to 92% by volume of methane (b) from 6 to 35% by volume of ethane (c) from 0 to 12% by volume of propane (d) from 0 to 1% by volume of butane (e) not more than 1% each of carbon dioxide or nitrogen (f) from 0.5% to 10% of ammonia or hydrogen fluoride the total being 100%, and such mixture being completely gaseous with no liquid phase at the temperature and pressure of intended operation. 19. A gas mixture, for use in a pipeline or storage facility at a pressure greater than 1,000 psia (6894 kPa) and a temperature of -40 degree F. to +100 degree F (from -40 degree C to 38 degree C), which comprises: (a) from 68 to 92% by volume of methane (b) from 6 to 35% by volume of ethane (c) from 0 to 12% by volume of propane (d) from 0 to 1% by volume of butane (e) not more than 1% each of carbon dioxide or nitrogen (f) at least 1% carbon monoxide the total being 100%, and such mixture being completely gaseous with no liquid phase at the temperature and pressure of intended operation. 20. A method of transporting natural gas which comprises: adding to said natural gas at least 0.5% (based on volume of the total mixture) of ammonia to form an ammonia-natural gas mixture which is gaseous at a chosen pressure and temperature of pipeline transport transporting said ammonia-natural gas mixture to a desired destination by a pipeline pressurized to at least 800 psia (5515 kPa) and at a temperature of between -40 degree F and 100 degree F (from -40 degree C to 38 degree C) and separating said ammonia from said natural gas. 21. A method as claimed in claim 20, in which the amount of ammonia is a least 4% by volume.