Liquid Hydrogen Disposal Piping to Prevent Outlet Air Solidification

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Solution Overview

Problem

The disposal of liquid hydrogen through piping over the ocean is hindered by the solidification of external air at the piping's distal end due to its low temperature, which can block the piping and hinder the disposal process.

Innovation Solution

The piping design includes an increased contact area at the distal-end-side portion with external air, or an annular ejecting portion that ejects hydrogen gas, or a vacuum layer and gas encapsulating layer to prevent air solidification, ensuring the piping remains above the freezing points of nitrogen and oxygen, and optionally uses a hydrogen supply line to vaporize liquid hydrogen for ejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If highly thermally insulated piping is used to transport liquid hydrogen, then thermal insulation performance is improved, but the distal end of the piping is cooled down to near the temperature of liquid hydrogen, causing external air to solidify and block the piping

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidpiping blockage risk
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The piping system applies different thermal insulation characteristics to different sections: the proximal end has high thermal insulation to minimize heat ingress, while the distal end has enhanced heat dissipation capability through increased external surface area contact with air, creating a temperature gradient that prevents air solidification at the critical outlet section

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention transitions from a uniform one-dimensional insulation approach to a multi-dimensional heat transfer system by adding radial heat dissipation pathways at the distal end through increased external surface area, allowing heat to be conducted from the liquid hydrogen to the piping wall and then dissipated to the surrounding air in three dimensions

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the piping outer peripheral part is cooled down by liquid hydrogen flow, then liquid hydrogen disposal efficiency is improved, but the temperature drops below the freezing points of nitrogen and oxygen, causing air solidification

Engineering Contradiction:
Improveliquid hydrogen disposal efficiencyVSAvoidpiping temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The invention changes the thermal parameters of the piping system by modifying the external surface area of the distal end section, thereby altering the heat transfer coefficients and thermal resistance to achieve optimal temperature distribution that maintains disposal efficiency while preventing air solidification

Inventive Principle:
Principle #35Parameter changes

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 configuration prevents the solidification of air at the piping's distal end, ensuring continuous liquid hydrogen disposal without blockages and maintaining the fluid inside the piping in a stable liquid state.

Implementation Method 1

radiation of cold energy is accelerated at the distal-end-side portion of the outer peripheral part

Methodology Applied
Scientific EffectRadiation: Thermal Radiation

Implementation Method 2

an outer pipe for forming a vacuum layer in a gap that is formed between the inner pipe and the outer pipe

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Implementation Method 3

the annular ejecting portion is configured to eject hydrogen gas at a distal end of the outer peripheral part of the piping

Methodology Applied
Scientific EffectGas ejection: Jet

Implementation Method 4

a cargo pump installed in the tank; and piping for transferring the liquid hydrogen sucked up by the cargo pump

Methodology Applied
Scientific EffectPumping: Pump

Data Source

PatentEP3296609B1Ship provided with piping for disposing of liquid hydrogen
Publication Date: 2022.02.23 KAWASAKI JUKOGYO KK
  • EP3296609B1 patent drawingFigure 1~2
  • EP3296609B1 patent drawingFigure 3~4
  • EP3296609B1 patent drawingFigure 5~6

AI summary

A ship according to one aspect of the present invention is a ship including piping for disposing of liquid hydrogen over ocean, the liquid hydrogen being a cargo stored in a tank. The piping includes an outer peripheral part that contacts external air. An area of contact between a distal-end-side portion of the outer peripheral part and the external air is greater than an area of contact between a remaining portion of the outer peripheral part and the external air.