# US 7,607,310 B2 · Storage of natural gas in liquid solvents and methods to absorb and segregate natural gas into and out of liquid solvents > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,310 B2 - Document ID: US7607310B2 - Status: Granted - Kind: B2 - Application number: 10/928,757 - Filed: 2004-08-26 - Published: 2006-03-02 - Granted: 2009-10-27 - Earliest claimed: 2004-08-26 - Assignees: SeaOne Maritime Corp. - Inventors: Ian Morris; Patrick A. Agnew; Bruce Hall - Web page: https://patentgrep.com/patent/US7607310B2 ## CPC - F17C 11/007: {for hydrocarbon gases, such as methane or natural gas, propane, butane or mixtures thereof [LPG]} - Y10T 137/0329: Mixing of plural fluids of diverse characteristics or conditions - Y10T 137/0352: Controlled by pressure - F17C: VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Systems and processes that facilitate the absorption of natural gas or methane through the interaction of moderate pressure and low temperature into a liquid or liquid vapor medium for storage and transport, and back into a gas for delivery to market. In a preferred embodiment, the absorptive properties of ethane, propane and butane under moderate conditions of temperature and pressure (associated with a novel mixing process) are utilized to store natural gas or methane at more efficient levels of compressed volume ratio than are attainable with natural gas alone under similar holding conditions. The preferred mixing process efficiently combines natural gas or methane with a solvent medium such as liquid ethane, propane, butane, or other suitable fluid, to form a concentrated liquid or liquid vapor mixture suited for storage and transport. The solvent medium is preferably recycled in the conveyance vessel on unloading of the natural gas. ## Claims ### Claim 1 A process of mixing natural gas with a hydrocarbon solvent to yield a liquid medium suited for storage and transport at greater storage densities than compressed natural gas at the same storage conditions, comprising: cooling natural gas and a solvent to temperatures in a range from below −40° F. to about −80° F., wherein the solvent is a liquid hydrocarbon, combining a flow stream of the natural gas having a molar flow rate with a flow stream of the liquid hydrocarbon solvent having a molar flow rate determined as a function of the molar flow rate of the flow stream of the natural gas causing a phase change of the combined flow streams of the natural gas and the liquid hydrocarbon solvent into a single phase liquid medium of natural gas absorbed in the hydrocarbon solvent, compressing the single phase liquid medium at pressures in a range of about 1200 psig to about 2150 psig, and storing the single phase liquid medium in a storage vessel, wherein the natural gas of the single phase liquid medium is stored at storage densities that exceed storage densities of compressed natural gas for the same pressure and temperatures. ### Claim 2 (depends on 1) The process of claim 1 wherein the compressing step includes compressing the liquid medium at pressures in a range of about 1200 psig to about 1440 psig. ### Claim 3 (depends on 2) The process of claim 2 wherein the cooling step includes cooling the gas and solvent to temperatures in a range from below −40° F. to about −60° F. ### Claim 4 (depends on 1) The process of claim 1 wherein the cooling step includes cooling the flow streams of natural gas and hydrocarbon solvent to temperatures in a range from below −40° F. to about −60° F. ### Claim 5 (depends on 1) The process of claim 1 wherein the hydrocarbon solvent is ethane. ### Claim 6 (depends on 1) The process of claim 1 wherein the hydrocarbon solvent is propane. ### Claim 7 (depends on 1) The process of claim 1 wherein the hydrocarbon solvent is butane. ### Claim 8 (depends on 1) The process of claim 1 wherein the natural gas is methane. ### Claim 9 (depends on 1) The process of claim 1 further comprising the steps of reducing the pressure of the single phase liquid medium of natural gas absorbed in the hydrocarbon solvent to separate the natural gas and hydrocarbon solvent, and heating the natural gas to gasify the natural gas. ### Claim 10 (depends on 9) The process of claim 9 further comprising the step of maintaining the liquid medium at a pressure of 1440 psig or less and at temperatures in a range from below −40° F. to −60° F. or above prior to reducing the pressure of the liquid medium. ### Claim 11 (depends on 9) The process of claim 9 further comprising the step of maintaining the liquid medium at a pressure of 1440 psig or less and at temperatures in a range from below −40° F. to −80° F. or above prior to reducing the pressure of the liquid medium. ### Claim 12 (depends on 9) The process of claim 9 further comprising the step of maintaining the liquid medium at a pressure of 2150 psig or less and at temperatures in a range from below −40° F. to −60° F. or above prior to reducing the pressure of the liquid medium. ### Claim 13 (depends on 9) The process of claim 9 further comprising the step of maintaining the liquid medium at a pressure of 2150 psig or less and at temperatures in a range from below −40° F. to −80° F. or above prior to reducing the pressure of the liquid medium. ### Claim 14 (depends on 9) The process of claim 9 further comprising the step of storing the hydrocarbon solvent in liquid phase for future use. ### Claim 15 (depends on 4) The process of claim 4 wherein the storage densities of the natural gas of the single phase liquid medium are in a volumetric ratio range of 215 ft3/ft3 to 335 ft3/ft3. ### Claim 16 (depends on 4) The process of claim 4 wherein the hydrocarbon solvent is ethane and wherein the storage densities of the natural gas of the single phase liquid medium are in a volumetric ratio range of 226 ft3/ft3 to 326 ft3/ft3. ### Claim 17 (depends on 4) The process of claim 4 wherein the hydrocarbon solvent is propane and wherein the storage densities of the natural gas of the single phase liquid medium are in a volumetric ratio range of 265 ft3/ft3 to 320 ft3/ft3. ### Claim 18 (depends on 4) The process of claim 4 wherein the hydrocarbon solvent is butane and wherein the storage densities of the natural gas of the single phase liquid medium are in a volumetric ratio range of 215 ft3/ft3 to 335 ft3/ft3. ### Claim 19 (depends on 4) The process of claim 4 wherein the storage densities of the natural gas of the single phase liquid medium are at least 1.23 to 1.66 times greater than that of compressed natural gas under the same temperature and pressure. ### Claim 20 (depends on 4) The process of claim 4 wherein the hydrocarbon solvent is ethane and wherein the storage densities of the natural gas of the single phase liquid medium are at least 1.23 to 1.36 times greater than that of compressed natural gas under the same temperature and pressure. ### Claim 21 (depends on 4) The process of claim 4 wherein the hydrocarbon solvent is propane and wherein the storage densities of the natural gas of the single phase liquid medium are at least 1.40 to 1.66 times greater than that of compressed natural gas under the same temperature and pressure. ### Claim 22 (depends on 4) The process of claim 4 wherein the hydrocarbon solvent is butane and wherein the storage densities of the natural gas of the single phase liquid medium are at least 1.33 to 1.43 times greater than that of compressed natural gas under the same temperature and pressure.