Heat Exchanger Flow Grouping for Stable Fluid Liquefaction
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Solution Overview
Problem
Existing liquefaction facilities face instability and potential mechanical failure due to reduced mass flow rates of hydrocarbon streams, leading to frictional pressure drops and liquid plug formation in heat exchangers, which can cause rapid thermal oscillations and mechanical issues.
Innovation Solution
A heat exchanger design with multiple primary groups of flow passages that can be selectively blocked in response to varying mass flow rates, maintaining frictional pressure drop and ensuring stable operation by directing the fluid stream through fewer passages, thereby accommodating reduced mass flows without increasing pressure drop requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the mass flow rate of the hydrocarbon stream is reduced, then the production flexibility and adaptability are improved, but the frictional pressure drop decreases leading to unstable cooling behavior and potential mechanical failure
Solution Approach 1:
The system dynamically adjusts the number of active flow passages based on the mass flow rate of the hydrocarbon stream. During turn-down operation, fewer flow passages are activated to maintain appropriate frictional pressure drop and stable cooling behavior, while at full capacity all passages are utilized for maximum production.
Solution Approach 2:
The heat exchanger flow passages are divided into multiple separable groups that can be independently activated or deactivated. This segmentation allows the system to adapt the number of active passages to match the production rate, maintaining optimal pressure drop characteristics across different operating conditions.
2Adaptability or versatility
If the number of flow passages is increased to accommodate reduced mass flow, then the adaptability is improved, but the device complexity and pressure drop requirements increase
Solution Approach 1:
The heat exchanger is designed with multiple discrete flow passage groups that can be selectively activated. This segmentation allows the system to accommodate varying mass flow rates without requiring a completely different heat exchanger configuration, reducing overall device complexity while maintaining adaptability.
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 design allows for stable operation at reduced mass flow rates, reducing the risk of mechanical failure and maintaining efficiency, while also being cost-effective and thermodynamically more efficient, capable of accommodating significant reductions in mass flow without the need for excessive pressure drop enhancements.
Implementation Method 1
each said primary group for carrying a part of the fluid stream through the heat exchanger and to indirectly cool said part against a refrigerant in the shell side of the heat exchanger to provide a liquefied fluid stream
Implementation Method 2
A reduction in the mass flow of the hydrocarbon stream from the designed operational conditions can result in a decrease in the frictional pressure drop of the hydrocarbon stream across the main heat exchanger(s), increasing the potential for unstable behaviour in the cooling process
Data Source
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AI summary
A fluid is cooled and liquefied in an apparatus with a heat exchanger (5) having a shell side (78) within its walls (85) and a plurality of flow passages extending through the shell side (78). The plurality of flow passages comprises two or more primary groups (40a, 40b) of one or more primary flow passages, each said primary group for carrying a part of the fluid stream through the heat exchanger (5) and to indirectly cool said part against a refrigerant in the shell side (78) of the heat exchanger (5) to provide a liquefied fluid stream (50, 70). A primary inlet header (6,6') connects the two or more primary groups (40a, 40b) of primary flow passages to a source of the fluid (10), and arranged to split the fluid stream between the two or more primary groups (40a, 40b) of primary flow passages. Means (25a, 25b) are provided for selectively blocking at least one of the two or more primary groups (40a, 40b) of primary flow passages whilst allowing the fluid stream to flow through the remaining unblocked primary groups of primary flow passages.