Light Oil Reflux Loop for Lean Natural Gas Heavies Removal
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Solution Overview
Problem
The existing heavies removal system in the LNG Optimized Cascade Process faces increased operating and capital expenditures due to higher lean reflux rates required for processing leaner natural gas feeds, leading to increased natural gas flow and compression needs in the reflux loop.
Innovation Solution
The system replaces the lean reflux stream with a light oil reflux stream, utilizing either a C4-C5 reflux stream or external condensate stream to enhance separation efficiency and reduce the need for gas compression, allowing for leaner feed processing and minimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lean reflux rate is increased to remove C6+ components from leaner natural gas feeds, then separation efficiency is improved, but operating expenditures and capital expenditures increase due to increased natural gas flow to compressors
Solution Approach 1:
The invention changes the physical state parameter of the reflux stream from gas phase to liquid phase by condensing it before returning to the heavies removal column. This parameter change eliminates the need for compression while maintaining the reflux function, thereby reducing energy consumption and operating expenditures while preserving separation efficiency.
Solution Approach 2:
The invention extracts the compression function from the reflux loop by condensing the reflux stream before it returns to the column. This removes the harmful element (gas compression requirement) while preserving the useful function (reflux for separation), thus eliminating the associated operating and capital expenditures.
2Productivity
If lean reflux rate is increased to process leaner natural gas feeds, then heavies removal capability is improved, but device complexity increases due to additional compression equipment
Solution Approach 1:
The invention extracts and removes the compression equipment from the reflux loop by implementing a condensed liquid reflux system. This eliminates the harmful element (device complexity) while preserving the useful function (heavies removal capability) through alternative means (liquid reflux instead of gas compression).
Solution Approach 2:
The invention introduces a condenser as an intermediary device that transforms the reflux stream from gas to liquid phase. This intermediary enables the system to achieve heavies removal without requiring compression equipment, thereby reducing device complexity while maintaining productivity.
3Reliability
If natural gas flow is increased in the reflux loop to maintain separation, then separation performance is maintained, but energy consumption increases due to compression requirements
Solution Approach 1:
The invention changes the phase parameter of the reflux stream from gas to liquid, which fundamentally alters the energy requirements. This parameter change eliminates compression energy consumption while maintaining adequate reflux flow rates to preserve separation performance and reliability.
Solution Approach 2:
The invention converts the harmful energy consumption associated with gas compression into a beneficial liquid reflux system. By condensing the reflux stream, the system eliminates the energy-wasting compression step while maintaining or even improving separation efficiency through controlled liquid reflux.
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 significantly reduces operational expenditures by over 80% and increases separation efficiency, enabling the processing of very lean gas feeds with minimal energy usage and reduced capital expenditures.
Implementation Method 1
flash drum bottoms is pumped through a heat exchanger as a light oil reflux input to the heavies removal column
Implementation Method 2
heavies removal column receiving and processing natural gas and light oil reflux
Implementation Method 3
The heavies removal column reboiler bottoms stream product is input to a debutanizer column
Data Source
AI summary
The invention relates to various nonlimiting embodiments that include methods, apparatuses or systems for processing natural gas comprising a heavies removal column processing natural gas and light oil reflux. The overhead stream goes to heavies treated natural gas storage. The heavies removal column reboiler bottoms stream product is input to a debutanizer column. The debutanizer column overhead lights are input to a flash drum where the bottoms is pumped through a heat exchanger as a light oil reflux input to the heavies removal column, while the debutanizer reboiler bottoms product is stored as stabilized condensate. Alternatively, debutanizer column overhead lights are sent to heavies treated gas storage and the bottoms stream product goes to a depentanizer column, the overhead lights are pumped through a heat exchanger as a light oil reflux input to the heavies removal column, while the depentanizer reboiler bottoms product is stabilized condensate.