Liquid Expander Power Recovery for Flexible LNG Compressor Layout
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Solution Overview
Problem
Existing LNG facilities face challenges in efficiently extracting energy from high-pressure streams for use in remote sections, as direct mechanical coupling of expanders and compressors requires close proximity, making it difficult to retrofit existing facilities and optimize equipment placement.
Innovation Solution
The method involves using liquid expanders to generate work from pressurized streams, converting this work into electricity, and using it to power compressors located elsewhere in the facility, allowing for energy extraction and utilization without the need for major reconfigurations, by employing a cascaded refrigeration process with multiple liquid expanders and generators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If direct mechanical coupling of expander and compressor is used, then energy extraction efficiency is improved, but equipment placement flexibility deteriorates
Solution Approach 1:
The patent replaces the direct mechanical coupling system with an electrical coupling system. The expander drives a generator to produce electricity, which then powers the compressor through an electrical motor. This substitution of mechanical connection with electrical connection allows the equipment to be placed in different locations while maintaining efficient energy transfer, as electrical energy can be transmitted over distances without significant loss.
Solution Approach 2:
The patent introduces electricity as an intermediary between the expander and compressor. Instead of direct mechanical coupling, the expander converts mechanical energy to electrical energy through a generator, and the compressor converts electrical energy back to mechanical energy through a motor. This intermediary approach enables flexible equipment placement while preserving energy extraction efficiency.
2Adaptability or versatility
If liquid expander with electrical coupling is used, then equipment placement flexibility is improved, but system complexity increases
Solution Approach 1:
The patent employs a standardized electrical coupling system that can be applied to various expander and compressor configurations throughout the LNG facility. The generator-motor electrical interface is a universal solution that works across different equipment types and locations, reducing the need for custom mechanical coupling designs and simplifying overall system integration despite the added electrical components.
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 enables efficient energy extraction and utilization from high-pressure streams, allowing for flexible placement of compressors and expanders, thereby optimizing energy use and facility design without the need for significant modifications.
Implementation Method 1
passing a pressurized stream through a liquid expander to reduce the pressure of the stream and generate work
Implementation Method 2
converting the work into electricity
Data Source
AI summary
A process and apparatus for the liquefaction of natural gas including at least one liquid expander for providing expansion of a high-pressure stream and powering a generator capable of producing electricity to be used to drive a compressor located elsewhere in the liquefaction apparatus. Particularly, a liquid expander is used to expand a high-pressure refrigerant stream and to power an electrical generator. The electricity provided by the generator can be used to power a compressor located in the same or a different refrigeration cycle as the liquid expander.