Sieve Bed Regeneration for Low-Energy LNG Gas Purification
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Solution Overview
Problem
Impurities in feedstock, such as water, carbon dioxide, sulfur, and hydrogen sulfides, complicate the processing of natural gas and can damage equipment, necessitating effective purification methods to produce high-quality liquid natural gas (LNG).
Innovation Solution
The use of multiple beds of sieve materials, arranged in stages for drying and purifying, with temperature and pressure swing adsorption techniques to remove impurities, and a regenerating process that extends the life of the sieve materials by heating and cooling them with purified and unpurified gas streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If amine systems or solvent-based systems are used to reduce carbon dioxide concentrations, then purification effectiveness is improved, but energy consumption increases significantly
Solution Approach 1:
The patent employs pressure swing adsorption (PSA) and temperature swing adsorption (TSA) to dynamically change pressure and temperature parameters, enabling the sieve material to selectively adsorb carbon dioxide under high pressure and release it under low pressure or elevated temperature, achieving effective purification without the high energy consumption of amine systems
Solution Approach 2:
The patent utilizes porous sieve materials with specific pore structures and surface properties that selectively adsorb carbon dioxide molecules while allowing methane to pass through, providing an energy-efficient alternative to solvent-based purification methods
2Use of energy by moving object
If sieve materials are used for carbon dioxide adsorption, then energy consumption is reduced, but the system requires significant residue gas for the adsorption process
Solution Approach 1:
The patent recovers the adsorbed carbon dioxide by reducing pressure or increasing temperature, allowing the sieve material to be regenerated and reused. The desorbed gas is separated and can be utilized or disposed of, minimizing the net residue gas requirement while maintaining low energy consumption
3Productivity
If sieve materials operate continuously without regeneration, then productivity is maintained, but the sieve material degrades rapidly and useful life is reduced
Solution Approach 1:
The patent implements periodic regeneration cycles where the sieve material is temporarily taken offline, subjected to pressure or temperature changes to desorb accumulated carbon dioxide, and then returned to service. This periodic maintenance extends the useful life of the sieve material while minimizing interruption to overall productivity
Solution Approach 2:
The system uses a portion of its own output (purified methane or process gas) to provide the temperature or pressure conditions necessary for regenerating the sieve material, enabling the system to maintain productivity while extending material life through self-supported regeneration
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
This method effectively reduces impurity concentrations, extends the life of sieve materials, and reduces energy consumption and residue gas requirements, making it suitable for small-scale LNG production facilities, while ensuring the production of high-quality methane for liquefaction.
Implementation Method 1
Some embodiments employ multiple beds of sieve materials that can remove impurities from the feedstock
Implementation Method 2
The embodiments may also use some of the dried, unpurified gas to heat and cool the beds of sieve material in both the purifying stage and the drying stage
Implementation Method 3
the embodiments may use some of the purified methane to cool the beds of sieve material found in the purifying stage
Implementation Method 4
with temperature and pressure swing adsorption techniques to remove impurities
Implementation Method 5
with temperature and pressure swing adsorption techniques to remove impurities
Data Source
AI summary
A system and process for regenerating sieve materials in a gas processing system. The process can include circulating a cooling gas through sieve material of a first bed, the cooling gas having a first concentration of carbon dioxide (CO2) suitable for liquefaction into a liquid natural gas (LNG) product. The process can also include circulating a regenerating gas through sieve material of a second bed, the regenerating gas having a second concentration of carbon dioxide (CO2) that is greater than the first concentration of carbon dioxide (CO2) of the cooling gas.