Concentric LNG Sampling Probe for Faster, Low-Boil-Off Sampling
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Solution Overview
Problem
Liquefied natural gas (LNG) sampling faces challenges such as premature boiling due to heat ingress, leading to unreliable sample data, and slow fluid flow rates resulting in time delays and waste of bypass flow.
Innovation Solution
A fast loop fluid sampling system with a probe arrangement featuring concentric or parallel supply and return passages, utilizing the Bernoulli effect for pressure differential to drive fluid flow, and a self-contained design for easy retraction and reduced cooling requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation and active cooling are used to prevent premature boiling, then sample integrity is improved, but device complexity and energy consumption increase
Solution Approach 1:
The invention extracts the cooling function from a separate active cooling system and integrates it into the return passage by utilizing the cold LNG sample itself as the cooling medium. The return passage carries cold LNG that naturally cools the supply passage through thermal conduction through the probe wall, eliminating the need for external cooling equipment.
Solution Approach 2:
The system uses the sampled LNG itself to provide the cooling function. The cold sample fluid circulating through the return passage automatically cools the supply passage and prevents premature boiling, making the system self-cooling without requiring external energy input or active cooling mechanisms.
2Speed
If a bypass line is used to increase flow rate, then sampling speed is improved, but fluid waste increases
Solution Approach 1:
The invention merges the cooling function and the sampling function into a single integrated flow loop. The same fluid stream that provides cooling also provides the sample, eliminating the need for a separate bypass line. The return passage serves dual purposes: cooling the supply passage and delivering sample fluid to the vaporizer.
Solution Approach 2:
The return passage is designed to serve multiple functions simultaneously: it acts as a cooling channel for the supply passage, a transport line for the sample fluid, and a return path for the two-phase flow. This multi-functionality eliminates the need for separate bypass lines and reduces overall system complexity.
3Loss of time
If liquid flow rate is increased to reduce time delay, then sampling timeliness is improved, but the system requires higher energy input and increases boil-off gas
Solution Approach 1:
The system utilizes periodic phase change of the LNG sample as it flows through the return passage. The liquid LNG periodically boils and forms two-phase flow, which naturally enhances heat transfer and maintains cooling efficiency. This periodic phase change allows the system to handle variable flow rates without requiring continuous high energy input.
Solution Approach 2:
The invention exploits the phase transition of LNG from liquid to two-phase flow in the return passage. This phase change provides intense cooling through latent heat absorption, allowing the system to maintain effective cooling even at higher flow rates without proportionally increasing energy input or boil-off gas.
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
The system minimizes time delays, reduces fluid waste, and maintains sample integrity by preventing premature vaporization, while eliminating the need for external pumps and reducing boil-off gas generation.
Implementation Method 1
utilizing the Bernoulli effect for pressure differential to drive fluid flow
Implementation Method 2
heat from the atmosphere seeps into the sample as it flows from the sample tap to the vaporizer
Implementation Method 3
This is typically addressed with insulation to slow heat transfer into the system from the atmosphere
Data Source
AI summary
A probe arrangement includes an elongated probe body and a fluid receiving device. The elongated probe body includes a supply passage extending axially from a distal supply port to a proximal supply port and a return passage concentrically surrounding the supply passage and extending axially from a distal return port to a proximal return port. The fluid receiving device includes a fluid receiving passage extending to a fluid receiving port, wherein the proximal return port is sealingly assembled with the fluid receiving port and the proximal supply port is in fluid communication with the fluid receiving port, such that the fluid receiving port provides a first flow path between the proximal supply port and the fluid receiving passage and a second flow path between the proximal supply port and the proximal return port.