Direct Sensing Gas Detection for LNG Hazardous Areas
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Solution Overview
Problem
Conventional gas detection systems in hazardous areas of gas carriers take too long to detect flammable gas leaks, leading to potential explosions due to delayed detection and incomplete analysis, especially in high-pressure systems like LNG carriers, and are prone to errors in sampling and analysis.
Innovation Solution
Installation of direct sensing type gas detectors and LOS (line of sight) infrared gas detectors in enclosed spaces for real-time detection, combined with exhaust fans for immediate ventilation to prevent gas accumulation and explosions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional sampling and analysis system is used, then gas concentration can be measured, but detection time is too long (30 minutes to 140 seconds) causing delayed response to gas leaks
Solution Approach 1:
The patent replaces the mechanical sampling system with optical detection technology. Infrared sensors and laser-based detectors directly measure gas concentration without physical sampling, eliminating the time delay caused by gas transport through pipelines while maintaining measurement precision.
Solution Approach 2:
The patent introduces optical fields (infrared radiation, laser beams) as intermediaries to detect gas molecules. These optical mediators interact with gas molecules directly in the hazardous area, enabling real-time detection without the need for mechanical sampling and transport systems.
2Area of stationary object
If gas sampling pipeline is extended to cover all sampling head locations, then complete area coverage is achieved, but gas transport time increases (up to 140 seconds) delaying detection
Solution Approach 1:
The patent replaces the extended mechanical sampling pipeline with distributed optical sensors positioned throughout the hazardous area. Each sensor independently detects gas locally, achieving complete area coverage without the time penalty of gas transport through long pipelines.
Solution Approach 2:
The patent divides the hazardous area into multiple detection zones, each monitored by independent optical sensors. This segmentation allows simultaneous detection across the entire area, eliminating the sequential sampling delay inherent in extended pipeline systems.
3Reliability
If gas detection equipment is installed in separate enclosed space (cargo compressor room), then equipment protection is improved, but detection response time increases (30 to 60 seconds) due to distance
Solution Approach 1:
The patent uses optical fields as intermediaries to bridge the gap between the hazardous area and protected detection equipment. Optical sensors can be positioned in safe zones while their detection fields extend into hazardous areas, providing both equipment protection and rapid response through direct optical measurement without gas transport delays.
4Measurement precision
If sequential sampling of multiple sampling heads is performed, then comprehensive gas analysis is achieved, but total analysis time reaches approximately 30 minutes
Solution Approach 1:
The patent replaces sequential mechanical sampling with parallel optical detection. Multiple optical sensors simultaneously monitor different locations and gas types, achieving comprehensive gas analysis in real-time rather than over a 30-minute sequential period.
Solution Approach 2:
The patent implements continuous real-time monitoring using optical sensors that continuously measure gas concentrations without interruption. This eliminates the stop-and-go nature of sequential sampling, maintaining continuous detection across all monitoring points simultaneously.
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
Enables immediate detection and ventilation of flammable gas leaks in hazardous areas, reducing the risk of explosions and ensuring safety in high-pressure systems by rapidly identifying and dispersing hazardous gases.
Implementation Method 1
LOS (line of sight) infrared gas detector
Data Source
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AI summary
A method of detecting leaking gas in a hazardous area of a gas carrier is disclosed. At least two direct sensing type gas detectors are installed in a hazardous area, an enclosed space of a gas carrier, or onshore or offshore facilities using boil-off gas, so that leaking gas can be immediately detected in the hazardous area or the enclosed space, and a warning alarm is issued or an emergency stop system is actuated depending upon a detected amount of leaking gas.