Liquid Hydrogen Cavern Filling via Heat Exchange Coil
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Solution Overview
Problem
Filling cavern storage facilities with liquid hydrogen (H2) poses a risk of catastrophic pressure drops due to temperature-induced pressure changes, similar to issues with LNG, as existing methods fail to manage the rapid gasification and resulting pressure fluctuations effectively, potentially leading to cavern collapse.
Innovation Solution
Introducing liquid hydrogen through a heat exchanger coil or line into the cavern, where it absorbs heat from geothermal sources and counterflowing gases, allowing gradual gasification over distance, thereby mitigating pressure drops by controlled release and using geothermal energy for temperature equilibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid hydrogen is introduced directly into the cavern for quick unloading, then productivity is improved, but the temperature drops causing pressure drop that threatens cavern stability
Solution Approach 1:
The filling process is divided into multiple phases: initial gas filling to establish pressure, followed by incremental liquid hydrogen additions with monitoring. This segmentation allows quick unloading capability while preventing catastrophic pressure drops by controlling the rate and amount of liquid hydrogen introduction.
Solution Approach 2:
Before introducing liquid hydrogen, the cavern is pre-filled with gaseous hydrogen to establish a minimum pressure buffer. This preliminary action creates a thermal and pressure buffer that mitigates the cooling effect when liquid hydrogen is subsequently introduced, preventing immediate cavern instability.
2Device complexity
If liquid hydrogen is introduced without preliminary gas filling, then device complexity is reduced, but temperature equilibration becomes uncontrolled causing harmful effects
Solution Approach 1:
Gaseous hydrogen serves as an intermediary substance between the external environment and the liquid hydrogen. It absorbs the thermal shock from liquid hydrogen introduction and gradually transfers energy, preventing direct temperature drops in the cavern while simplifying the overall system by using the cavern's own gas as the mediator.
3Productivity
If conventional compression methods are used for quick filling, then productivity is improved, but the heat of compression causes temperature increase that requires energy-intensive cooling
Solution Approach 1:
The heat of compression, normally a harmful byproduct requiring energy-intensive cooling, is converted into a beneficial thermal source. The compressed gas provides the exact amount of heat needed to gasify the liquid hydrogen, eliminating external cooling requirements and reducing overall energy consumption while maintaining fast filling speeds.
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 method prevents excessive pressure drops, ensuring cavern stability by maintaining pressure within safe limits during hydrogen introduction, allowing for efficient and safe filling of large caverns without energy-intensive gasification processes.
Implementation Method 1
the liquid hydrogen (H2) is fed into the cavern through a heat exchanger coil or a pipe ('coil tubing'). The heat exchanger coil or pipe is present in the cased borehole that leads to the cavern head. When the liquid hydrogen (H2) is introduced into the heat exchanger coil or pipe, the liquid hydrogen (H2) absorbs heat from the rock and/or the counterflowing hydrogen (H2), natural gas (CH4) or mixed gas above the cavern.
Implementation Method 2
the liquid hydrogen (H2) absorbs heat from the rock and/or the counterflowing hydrogen (H2), natural gas (CH4) or mixed gas above the cavern
Implementation Method 3
Liquid hydrogen (H2) still arrives at the cavern head. This liquid hydrogen (H2) is spread out by a baffle plate at the end of the heat exchanger coil or pipe. As a result, the liquid hydrogen (H2) gasifies during free fall in the cavern over a distance of up to 300 m.
Implementation Method 4
the liquid hydrogen (H2) gasifies during free fall in the cavern
Implementation Method 5
Depending on the depth of the cavern, the prevailing temperature of the geothermal energy there can heat the natural gas (CH4) in the cavern or cool the natural gas (CH4) in the cavern using the heat of compression that is lost in the large gas volume in the cavern.
Data Source
Figure 1
AI summary
The invention relates to a method for filling a cavern 100 of a cavern storage facility (101) with liquid hydrogen, characterized by inserting a heat exchanger coil (110) or a pipe ('coil tubing') into a piped borehole (120) leading from the earth's surface (200) to the cavern head (130), closing off an outlet (111) of the heat exchanger coil (110) or the pipe with a baffle plate (112), introducing 10 m³ to 50 m³ of liquid hydrogen (H₂) (300) into the heat exchanger coil (110) or into the pipe, waiting until the pressure in the cavern of the cavern storage facility (100) has risen again to 70% to 120% of the original pressure, and introducing another 10 m³ to 50 m³ of liquid hydrogen (H₂). (300) into the heat exchanger coil (110) or into the line, the waiting and reintroduction being repeated until a preselected fill quantity of the cavern storage (100) is reached.