Liquefaction system
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Solution Overview
Problem
Existing natural gas liquefaction methods using open-loop refrigeration cycles face inefficiencies, high capital costs, and impracticality with coil wound heat exchangers due to high pressure drop losses and power requirements, limiting their practical application.
Innovation Solution
A method and system that divides a cooled combined feed stream into multiple streams for sequential cooling and flashing, utilizing a coil wound heat exchanger for indirect heat exchange and separation of liquid and vapor fractions, allowing for efficient liquefaction with reduced capital costs and improved mechanical design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coil wound heat exchanger is used with multiple refrigerant streams on the cold side, then cooling duty can be provided, but the design becomes impractical due to high pressure drop losses and very high power requirements
Solution Approach 1:
The cold side of the heat exchanger is divided into multiple passages, with each passage handling a single refrigerant stream. This segmentation allows efficient heat transfer while maintaining manageable pressure drops and power requirements for each individual stream, avoiding the impracticality of trying to fit multiple streams into a single coil wound heat exchanger shell side.
2Quantity of substance
If multiple refrigerant streams are placed on the shell side of a heat exchanger, then cooling capacity increases, but the device complexity and impracticality increase due to accommodation limitations
Solution Approach 1:
Instead of attempting to accommodate multiple refrigerant streams in the shell side of a single heat exchanger, the invention divides the cold side into multiple passages, each dedicated to a single refrigerant stream. This segmentation maintains cooling capacity while significantly reducing design complexity and avoiding the accommodation problems inherent in multi-stream shell side configurations.
3Temperature
If high pressure drop losses are accepted to use a coil wound heat exchanger with multiple streams, then cooling duty is achieved, but the power requirement becomes very high and impractical
Solution Approach 1:
The heat exchanger cold side is segmented into multiple passages, with each passage optimized for a single refrigerant stream. This approach achieves the required cooling duty while maintaining reasonable pressure drops and power requirements, making the system practically applicable rather than theoretically possible but impractical.
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
Enhances efficiency, reduces capital costs, and improves mechanical design by utilizing a coil wound heat exchanger for natural gas liquefaction, achieving improved cooling and liquefaction processes.
Implementation Method 1
cooling the feed stream to form a cooled feed stream and condensing the refrigerant via indirect heat exchange with the feed stream
Implementation Method 2
The tube side defining one or more passages through the heat exchanger section for cooling the one or more feed streams
Implementation Method 3
condensing the refrigerant via indirect heat exchange with the feed stream
Implementation Method 4
the shell side defining a passage through the heat exchanger section for condensing the refrigerant
Implementation Method 5
expanding the high pressure combined feed stream to cool the stream, thereby forming a cooled combined feed stream
Implementation Method 6
separating the liquid and vapor fractions of the two-phase stream to form a liquid stream and a gaseous stream
Data Source
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AI summary
Described herein are methods and systems for liquefying natural gas using an open-loop natural gas refrigeration cycle; coil wound heat exchanger units suitable for cooling one or more feed streams, such as for example one or more natural gas feed streams, via indirect heat exchange with a gaseous refrigerant; and methods and systems for removing heavy components from a natural gas prior to liquefying the natural gas using an open-loop natural gas refrigeration cycle.