Continuous mixed refrigerant optimization system for the production of liquefied natural gas (LNG)
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Solution Overview
Problem
Liquefied natural gas (LNG) plants typically operate sub-optimally due to fixed mixed refrigerant (MR) compositions, leading to reduced production and increased costs, as changes in ambient temperature and feedstock composition cannot be accommodated during normal operation.
Innovation Solution
A system and method for continuously adjusting the composition of the MR fluid within a liquefaction system by separating and reintroducing heavy and light components, allowing for real-time optimization of the MR fluid's composition, pressure, and flow rate to match varying operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the mixed refrigerant composition is kept constant during plant operation, then the system structure remains simple and reliable, but the plant performs sub-optimally during the majority of its operation
Solution Approach 1:
The patent implements dynamic adjustment of mixed refrigerant composition by introducing variable flow rate controls that allow the refrigerant composition to change continuously based on operating conditions. This enables the system to adapt to varying ambient temperatures and feedstock compositions without requiring complete system redesign or shutdowns.
Solution Approach 2:
The patent changes the physical-chemical parameters of the mixed refrigerant by adjusting the flow rates of individual refrigerant components. By varying the composition ratios of different refrigerants in the mixed stream, the system optimizes its performance for different operating conditions while maintaining continuous operation.
2Productivity
If the mixed refrigerant composition is changed to optimize performance, then LNG production efficiency improves, but the system requires shutdowns for composition adjustments
Solution Approach 1:
The patent ensures continuous operation of the LNG plant by implementing online composition adjustment capabilities. The mixed refrigerant composition can be modified continuously during operation through variable flow rate controls, eliminating the need for periodic shutdowns to adjust refrigerant mix ratios for changing operating conditions.
Solution Approach 2:
The system transitions from static to dynamic operation by enabling real-time adjustment of refrigerant flow rates. This dynamic control allows the plant to maintain optimal performance across varying conditions without interruption to LNG production.
3Adaptability or versatility
If the mixed refrigerant composition is adjusted frequently, then the plant operates optimally under varying conditions, but the complexity of control systems increases
Solution Approach 1:
The patent implements feedback control mechanisms that continuously monitor operating conditions such as ambient temperature and feedstock composition. Based on this feedback, the system automatically adjusts the mixed refrigerant composition to maintain optimal performance, reducing the need for complex manual control while adapting to varying conditions.
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 enhances the efficiency and profitability of LNG production by enabling continuous optimization of the MR fluid composition, pressure, and flow rate, reducing operational costs and improving LNG production efficiency.
Implementation Method 1
During a compression and condensing process, heavy components within the MR fluid can condense prior to light components
Implementation Method 2
heat can be transferred from the methane-containing vapor to the MR fluid to thereby condense the methane-containing vapor into a liquefied natural gas (LNG)
Data Source
AI summary
Systems and methods are provided for adjusting a composition, pressure, and/or flow rate of a mixed refrigerant (MR) fluid in a liquefaction system to provide refrigeration to natural gas (NG) feedstock to produce liquefied natural gas (LNG). The MR fluid that is in circulation within a liquefaction system can include heavy components and light components. During LNG production, heavy components and/or light components of the MR fluid can be selectively removed from, and reintroduce into the MR fluid, thereby altering the composition of the remaining MR fluid in circulation. Adjusting the composition of the MR fluid in circulation within a liquefaction system can allow the system to be optimized to maximize efficiency, LNG production, and or profitability while the system is in operation.