Ship Reliquefaction System Nitrogen Leak Detection at Start-Up
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing reliquefaction systems for ships lack effective methods to promptly detect leaks in heat exchangers during initial start-up or restart, posing safety risks due to the use of extremely cold, flammable substances.
Innovation Solution
A leakage detection system that includes a refrigerant charge line connected to an inventory tank filled with nitrogen, allowing nitrogen to be supplied to the refrigerant compressor during start-up or restart to detect leaks in the refrigerant circulation line and other pipelines connected to the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the reliquefaction system uses extremely cold nitrogen refrigerant, then liquefaction efficiency is improved, but safety risk increases due to potential leakage of cold, flammable substances
Solution Approach 1:
The system performs preliminary leak detection by introducing nitrogen gas through the refrigerant charge line before actual operation begins. This preliminary action identifies potential leakage points in the heat exchanger and connected pipelines, allowing operators to address safety concerns before introducing the hazardous cold nitrogen refrigerant, thus maintaining both efficiency and safety.
2Reliability
If the system performs comprehensive leak detection before start-up, then safety is improved, but preparation time increases
Solution Approach 1:
The leak detection function is merged with the existing refrigerant charging process. The refrigerant charge line, which is already part of the system for introducing refrigerant, is utilized to introduce nitrogen for leak detection. This merging eliminates the need for separate detection equipment and procedures, achieving comprehensive safety checks without adding significant preparation time.
Solution Approach 2:
The system uses itself to perform leak detection by introducing nitrogen through its own refrigerant charge line and monitoring pressure changes or flow characteristics within the existing refrigerant circulation system. This self-service approach avoids external detection equipment and integrates safety verification into the normal operational procedures.
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 prompt detection of leaks in the heat exchanger and connected pipelines, reducing preparation time and ensuring safety by integrating leak detection with the refrigerant charging process.
Implementation Method 1
allowing nitrogen to be supplied to the refrigerant compressor during start-up or restart to detect leaks in the refrigerant circulation line
Implementation Method 2
a heat exchanger cooling the compressed gas from the compressor through heat exchange with refrigerant
Implementation Method 3
a refrigerant compressor disposed on the refrigerant circulation line to compress the refrigerant discharged from the heat exchanger
Implementation Method 4
a refrigerant expander expanding and cooling the refrigerant compressed by the refrigerant compressor
Data Source
AI summary
A leakage detection system includes: a gas supply line along which boil-off gas is supplied to a compressor; a reliquefaction line along which the compressed boil-off gas is cooled and reliquefied through a heat exchanger and is returned to a storage tank; a refrigerant circulation line along which a refrigerant is circulated; a refrigerant compressor to compress the refrigerant discharged from the heat exchanger; a refrigerant expander expanding and cooling the compressed refrigerant compressed by the refrigerant compressor and having been cooled through the heat exchanger and supplying the cooled refrigerant back to the heat exchanger; and a refrigerant charge line connecting an inventory tank filled with nitrogen to an upstream side of the refrigerant compressor. Upon initial start-up or restart of a reliquefaction process, the nitrogen is supplied to the upstream side of the refrigerant compressor via the refrigerant charge line to detect leaks in the refrigerant circulation line.