Plate-Fin LNG Vaporizer With Inert Gas Buffer Passages
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Solution Overview
Problem
Existing methods for vaporizing cryogenic liquids like liquefied natural gas (LNG) using heat exchange with calorigenic fluids are inefficient, prone to contamination, and vulnerable to thermal shocks during shutdowns and restarts, particularly in tubular geometries and bulky installations.
Innovation Solution
A plate and fin heat exchanger design where each passage of the first fluid (LNG) is separated from the corresponding passage of the second fluid (gaseous nitrogen) by an auxiliary passage containing fins through which an inert gas circulates, enhancing thermal efficiency and preventing contamination by interposing inert gas passages between LNG and nitrogen passages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If tubular heat exchangers are used for vaporizing LNG, then thermal efficiency is improved, but the risk of contamination and vulnerability to thermal shocks increases
Solution Approach 1:
An auxiliary passage containing an inert gas (nitrogen) is introduced between the LNG passage and the calorigenic gas passage. This intermediary passage acts as a buffer that prevents direct contact between LNG and calorigenic gas, eliminating contamination risk while maintaining thermal efficiency through controlled heat exchange. The inert gas serves as a mediator that protects against both contamination and thermal shocks during shutdowns and restarts.
2Reliability
If plate and fin heat exchangers are used with intermediate heat transfer liquid, then contamination risk is reduced, but the installation becomes bulky
Solution Approach 1:
The invention extracts and eliminates the intermediate heat transfer liquid from the system. Instead of using a liquid intermediary that requires bulky containment and circulation systems, the patent uses a gas-phase inert atmosphere in the auxiliary passage. This extraction of the liquid intermediary component significantly reduces installation size while maintaining contamination prevention through the inert gas barrier.
3Use of energy by moving object
If auxiliary passages with inert gas are introduced between LNG and nitrogen passages, then thermal efficiency is improved and contamination is prevented, but device complexity increases
Solution Approach 1:
The auxiliary passage containing inert gas is merged into the overall heat exchanger structure as an integrated component rather than a separate addition. The passage is formed as part of the plate and fin assembly, with the inert gas serving multiple functions simultaneously: thermal buffering, contamination prevention, and pressure equalization. This merging approach minimizes structural complexity while achieving multiple protective functions.
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 improves thermal efficiency, prevents contamination, and mitigates thermal shocks by using inert gas to manage pressure differences and facilitate controlled cooling during start-ups, resulting in a more compact and reliable heat exchange process.
Implementation Method 1
heating a first fluid by heat exchange with a second fluid in a plate and fin heat exchanger
Implementation Method 2
each passage of the first series is separated from the closest passage of the second series by an auxiliary passage containing fins through which an inert gas circulates
Implementation Method 3
the inert gas is at a pressure at least 0.1, or even at least 0.5 bars higher than those of the first fluid and of the second fluid
Implementation Method 4
vaporization of a cryogenic liquid, for example liquefied natural gas, by heat exchange with a calorigenic fluid
Implementation Method 5
the first fluid heats up by heat exchange with a second fluid
Data Source
Figure 1~4
Figure 5~6
AI summary
In a method for heating a first fluid through heat exchange with a second fluid in an exchanger having plates and blades, wherein the first fluid heats up in a first series of separate channels and the second fluid cools in a second series of separate channels, each channel of the first series is separated from the closest channel in the second series by a bladed auxiliary channel where an inert gas flows.