Natural Gas Storage in Light-Hydrocarbon Solvents
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Solution Overview
Problem
Current natural gas storage and transportation methods, such as LNG, PLNG, and CNG, face challenges in achieving high cargo density, reducing process energy consumption, and minimizing containment vessel mass, especially for remote or stranded gas reserves, due to limitations in design codes and energy efficiency.
Innovation Solution
The development of Compressed Gas Liquid (CGL) technology, which involves creating and storing a liquid phase mix of natural gas and light-hydrocarbon solvents under specific temperature and pressure conditions, using solvents like ethane, propane, and butane, to enhance volumetric and mass ratios within lighter containment systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional LNG, PLNG, or CNG systems are used for natural gas storage and transportation, then the natural gas can be stored and transported, but the cargo density is limited and containment vessel mass is high
Solution Approach 1:
A liquid hydrocarbon solvent acts as an intermediary medium to dissolve natural gas, creating a liquid-phase mixture that achieves higher cargo density. The solvent enables natural gas to be stored at higher densities without requiring extremely high pressures or temperatures, thereby reducing containment vessel mass while increasing the quantity of natural gas that can be stored per unit volume
Solution Approach 2:
The system changes the physical state parameters of natural gas by dissolving it in a liquid hydrocarbon solvent at moderate temperatures and pressures. This parameter change allows the natural gas to be stored in a liquid phase with higher density than traditional CNG or PLNG methods, improving cargo density without proportionally increasing containment vessel mass
2Quantity of substance
If higher pressure is applied to increase natural gas density in CNG systems, then cargo density improves, but containment vessel mass increases due to design code limitations
Solution Approach 1:
The liquid hydrocarbon solvent serves as a mediator that enables natural gas to achieve high density without extreme pressure. The solvent molecules interact with natural gas molecules, allowing the mixture to be compressed to higher densities at moderate pressures, thus avoiding the need for heavy containment vessels designed for high-pressure operation
3Productivity
If LNG systems are used for remote reserves, then natural gas can be transported, but the implementation cost is high and economies of scale are required
Solution Approach 1:
The system uses readily available liquid hydrocarbon solvents (such as pentane, hexane, or other light hydrocarbons) that can be obtained at low cost and do not require expensive specialized infrastructure. These solvents act as disposable or recyclable media that enable transportation capability without the high implementation costs of LNG systems
Solution Approach 2:
By changing the storage and transportation parameter from cryogenic temperatures (LNG) to moderate temperatures with liquid solvent dissolution, the system achieves transportation capability for remote reserves without requiring expensive LNG infrastructure. The parameter change enables use of simpler, less expensive containment and transportation vessels
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
CGL technology achieves improved cargo density and reduced energy consumption compared to traditional methods, allowing for more efficient storage and transportation of natural gas with better mass-to-containment ratios, making it suitable for remote reserves that were previously uneconomical to exploit.
Implementation Method 1
storing the CGL product under temperature and pressure conditions that facilitate improved volumetric ratios of the stored gas within containment systems
Implementation Method 2
pressure conditions ranging from about 300 psig to about 1800 psig
Implementation Method 3
temperature conditions from less than −80° F. to about −120° F.
Data Source
AI summary
Systems and methods to create and store a liquid phase mix of natural gas absorbed in light-hydrocarbon solvents under temperatures and pressures that facilitate improved volumetric ratios of the stored natural gas as compared to CNG and PLNG at the same temperatures and pressures of less than −80° to about −120° F. and about 300 psig to about 900 psig. Preferred solvents include ethane, propane and butane, and natural gas liquid (NGL) and liquid pressurized gas (LPG) solvents. Systems and methods for receiving raw production or semi-conditioned natural gas, conditioning the gas, producing a liquid phase mix of natural gas absorbed in a light-hydrocarbon solvent, and transporting the mix to a market where pipeline quality gas or fractionated products are delivered in a manner utilizing less energy than CNG, PLNG or LNG systems with better cargo-mass to containment-mass ratio for the natural gas component than CNG systems.