Open-Loop LNG Liquefaction with Integrated NGL Recovery
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Solution Overview
Problem
Existing methods for removing natural gas liquids (NGLs) and liquefying natural gas require separate front-end NGL extraction units and additional feed compression equipment, leading to increased capital costs and operational complexity.
Innovation Solution
An integrated open-loop refrigeration cycle system that combines a front-end NGL unit with a natural gas liquefaction unit, eliminating the need for feed compression equipment by using the natural gas feed as a continuous refrigerant source, and incorporating a distillation column for separation and reflux to enhance NGL recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a stand-alone front-end NGL extraction unit is used to remove natural gas liquids, then NGL recovery is achieved, but additional feed compression equipment is required and capital costs increase
Solution Approach 1:
The patent combines the NGL extraction unit and the natural gas liquefaction unit into a single integrated system. The NGL extraction column and liquefaction column share common equipment including compressors, heat exchangers, and refrigerant circulation systems. This merging eliminates the need for separate feed compression equipment while maintaining effective NGL recovery, directly resolving the technical contradiction between NGL recovery and equipment complexity.
2Quantity of substance
If separate NGL extraction and liquefaction units are used, then NGL removal is effective, but capital costs increase due to additional equipment
Solution Approach 1:
The integrated system employs multi-functional equipment that serves multiple purposes. For example, the compressor serves both NGL extraction and liquefaction functions; heat exchangers are used for both refrigeration and process heating; and the distillation column performs both NGL separation and natural gas liquefaction. This universality reduces the total equipment count and capital costs while maintaining effective NGL removal.
3Adaptability or versatility
If traditional separate units are used for NGL extraction and liquefaction, then process functionality is achieved, but operating complexity increases
Solution Approach 1:
The patent merges the control systems and operational procedures of NGL extraction and liquefaction into a unified integrated process. The refrigerant circulation system serves both units simultaneously, and the shared equipment requires coordinated but simplified operation. This integration reduces the number of independent systems that must be monitored and controlled, thereby reducing operating complexity while maintaining full process functionality.
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 approach reduces capital costs and operating complexity while achieving similar NGL recovery levels to standalone units, with improved efficiency and simplified design by integrating the NGL extraction and liquefaction processes.
Implementation Method 1
expanding and/or cooling a natural gas feed stream to form a cold stream
Implementation Method 2
cooling at least a first portion of the compressed refrigerant to form a first cold refrigerant stream
Implementation Method 3
expanding the first cold refrigerant stream and separating the stream into liquid and vapor phases to form a first liquefied natural gas stream
Implementation Method 4
introducing the expanded and/or cooled natural gas feed stream into a distillation column...separating the expanded and/or cooled natural gas feed stream into a natural gas liquids stream and a natural gas vapor stream
Data Source
AI summary
Methods and systems for removing natural gas liquids from a natural gas feed stream and for liquefying the natural gas feed stream so as to produce a liquefied natural gas (LNG) stream and a natural gas liquids (NGL) stream.