Machine Learning for Mixed Refrigerant Composition in LNG Plants

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Solution Overview

Problem

Liquefied natural gas plants face challenges in optimizing production efficiency due to changes in difficult-to-control operating conditions such as feed gas composition and pressure, and ambient temperature, which affect the composition of the mixed refrigerant used for cooling.

Innovation Solution

A method using machine learning to create a training model that predicts the production efficiency of liquefied natural gas, allowing for real-time determination of an optimal mixed refrigerant composition to improve efficiency, even under changing conditions, by associating operating conditions and operation results in the plant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional control methods are used to maintain stable operating conditions, then control stability is improved, but the ability to adapt to changing feed gas composition and ambient temperature deteriorates

Engineering Contradiction:
Improvecontrol stabilityVSAvoidadaptability to changing conditions
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptation by training a machine learning model with historical operation data that captures varying operating conditions (feed gas composition, ambient temperature) and their corresponding optimal mixed refrigerant compositions. The model dynamically determines the optimal refrigerant composition based on current operating conditions, enabling the system to adapt to changing conditions while maintaining production efficiency.

Inventive Principle:
Principle #15Dynamics

2Productivity

If machine learning model is implemented to determine optimal mixed refrigerant composition, then production efficiency is improved, but system complexity increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical control systems with a machine learning-based information processing system. Instead of using multiple sensors and complex control algorithms to determine optimal refrigerant composition, the system uses a trained model that processes operating condition data and outputs optimal composition recommendations, simplifying the overall control architecture while improving efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If real-time optimization of mixed refrigerant composition is performed, then production efficiency is improved, but measurement and detection requirements increase

Engineering Contradiction:
Improveproduction efficiencyVSAvoidmeasurement requirements
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses historical operation data as a virtual copy of actual plant operations to train the machine learning model. This training data captures the relationships between operating conditions and optimal refrigerant compositions without requiring real-time complex measurements. The model then uses this learned knowledge to determine optimal compositions in real-time based on readily available operating condition data.

Inventive Principle:
Principle #26Copying

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

Enables the determination of a candidate mixed refrigerant composition that enhances production efficiency in liquefied natural gas plants, even when operating conditions are difficult to control, by using a training model generated from historical data or simulation data, facilitating improved operational settings.

Implementation Method 1

a main cryogenic heat exchanger (24) configured to generate liquefied natural gas from a light component of a feed gas via heat exchange between the light component and a mixed refrigerant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a compressor (27) configured to be driven using some of the feed gas and the liquefied natural gas as fuel and compress the mixed refrigerant

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentUS12253306B2Method and system for determining operating conditions of liquefied natural gas plant
Publication Date: 2025.03.18 CHIYODA CORP
  • US12253306B2 patent drawing
  • US12253306B2 patent drawing
  • US12253306B2 patent drawing

AI summary

A method for determining an operating condition of a liquefied natural gas plant (2) includes preparing a training model (88) generated by machine learning using training data in which operating conditions data including a composition of a feed gas, a composition of a mixed refrigerant, and an ambient temperature and operation result data including a production efficiency of a liquefied product containing liquefied natural gas and a heavy component of the feed gas are associated together; and determining, as one new operating condition, a composition of the mixed refrigerant that optimizes a production efficiency of the liquefied natural gas predicted by the training model (88) from a latest composition of the feed gas in the liquefied natural gas plant (2) and a latest ambient temperature.