Cryogenic Vaporizer With Onboard Mist Separator
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Solution Overview
Problem
The existing system for vaporizing cryogenic gas-liquid mixtures from inter barrier spaces in cryogenic storage tanks results in excessively high temperatures at the outlet of the vaporizer, which can damage centrifugal compressor impellers, and requires connection to an onshore terminal for cooling, making it impractical to drain the inter barrier space while at sea.
Innovation Solution
A system that vaporizes the cryogenic gas-liquid mixture using cryogenic liquid stored onboard, where the cryogenic liquid is sprayed into the vaporized mixture for direct heat exchange, reducing the temperature below -50°C, and includes a mist separator to remove droplets, eliminating the need for onshore connection and controlling temperature and pressure to protect the compressor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the vaporizer is sized for high flow rates to ensure adequate vaporization capacity, then the vaporization function is improved, but the outlet temperature becomes excessively high which can damage the compressor impeller
Solution Approach 1:
The patent introduces a cooling medium (typically cold natural gas or refrigerant) as an intermediary substance that absorbs excess heat from the vaporized cryogenic mixture. This mediator allows the vaporizer to maintain high outlet temperatures for adequate vaporization while the cooling medium reduces the temperature to safe levels for the compressor, resolving the contradiction between vaporization capacity and temperature control
Solution Approach 2:
The patent segments the temperature control function from the vaporization function by introducing a separate cooling section downstream of the vaporizer. The vaporizer focuses on complete vaporization at high temperatures, while the subsequent cooling section independently manages temperature reduction, allowing each component to be optimized for its specific function without compromising the other
2Temperature
If a cooling system using cold natural gas from an onshore terminal is used to reduce the temperature, then the temperature control is improved, but the system requires connection to an onshore terminal which makes it impractical to drain the inter barrier space while at sea
Solution Approach 1:
The patent modifies the cooling system to use cooling resources available onboard the vessel itself, such as cold natural gas from the cargo tanks or onboard refrigeration systems, rather than requiring external onshore terminal infrastructure. This self-service approach allows the temperature control function to be performed independently at sea, resolving the contradiction between effective cooling and operational independence
Solution Approach 2:
The patent designs the cooling system to utilize existing onboard systems that serve multiple purposes - for example, using cold natural gas from cargo tanks that are already being cooled for storage, or using the vessel's refrigeration system that serves both cargo cooling and now compressor inlet cooling. This multi-functionality eliminates the need for dedicated external cooling infrastructure while maintaining effective temperature control
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 effectively cools the vaporized mixture to safe temperature levels for the compressor, allowing for safe operation at sea without the need for onshore terminals, while maintaining system pressure and preventing damage to compressor components.
Implementation Method 1
a vaporizer (5) for vaporizing the cryogenic gas-liquid mixture
Implementation Method 2
a shell and tube heat exchanger in which the liquid part of the cryogenic gas-liquid mixture, that is the LNG from the IBS, is vaporized by indirect heat exchange with steam
Implementation Method 3
the cryogenic liquid being sprayed into the vaporized cryogenic gas-liquid mixture... a direct heat exchange between the two fluids takes place
Implementation Method 4
the cryogenic liquid vaporizes within the vaporized cryogenic gas-liquid mixture, reducing the overall temperature of the resulting cold mixture
Implementation Method 5
a mist separator for separating off droplets of the cryogenic liquid from the cold mixture
Implementation Method 6
a compressor (9)... the aspiration of the compressor creating a depressurization within the system for vaporizing the cryogenic gas-liquid mixture
Data Source
Figure 1~2
AI summary
System for vaporizing a cryogenic gas-liquid mixture comprising a cryogenic gas-liquid mixture supply line, a vaporizer, spraying means for spraying a cryogenic liquid into the vaporized cryogenic gas-liquid mixture at the outlet of the vaporizer, a mist separator for separating droplets of cryogenic liquid from the vaporized cryogenic gas-liquid mixture and a compressor. The temperature at the inlet of the compressor is controlled with a control valve located on a cryogenic liquid supply line.