Cold Cryogenic Liquid Supply Chain With Low-Heat Hydrogen Transfer
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Solution Overview
Problem
Conventional liquid hydrogen delivery methods introduce significant heat into the final vessel, leading to increased venting and inefficiencies, as the cold cryogenic liquid is converted to gas, reducing the usable amount of hydrogen delivered.
Innovation Solution
A method and system that involves pressure equalization between the delivery tank and the final vessel, using a centrifugal pump to transfer liquid hydrogen while minimizing heat input, allowing gas to flow between the two to maintain pressure without external heating, and utilizing subcooling coils to remove heat from the final vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a reciprocating pump is used to pressurize liquid hydrogen from storage tank to fueling pressures, then the hydrogen can be delivered to vehicles, but significant heat is introduced into the cryogenic liquid due to heat of vapor returning to the vessel from pump operation and from natural heat leak
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the liquid hydrogen storage tank and the pump. This heat exchanger allows heat to be removed from the liquid hydrogen before it enters the pump, preventing the heat of vaporization from returning to the vessel. The heat exchanger acts as a mediator that decouples the pressurization function from the thermal contamination.
Solution Approach 2:
The harmful heat transfer process is extracted and separated from the main liquid hydrogen storage system. By implementing a heat exchanger, the heat that would otherwise be trapped in the liquid hydrogen is extracted and dissipated to the environment, preventing it from accumulating in the storage vessel during pump operation.
2Quantity of substance
If liquid hydrogen is delivered at a low temperature/heat content, then there is a higher capacity to absorb heat before the liquid hydrogen reaches the maximum pressure in the vessel, but conventional delivery methods introduce significant heat into the final vessel
Solution Approach 1:
Heat removal is performed as a preliminary action before the liquid hydrogen enters the final vessel. The heat exchanger is positioned to remove heat from the liquid hydrogen during transfer, so that when the cold liquid reaches the final vessel, it has already been pre-cooled, preventing heat accumulation that would otherwise occur during storage and delivery.
3Stability of the object's composition
If the saturation pressure of LH2 is increased to match vessel pressure, then heat can be absorbed without vaporization, but any additional heat causes LH2 to vaporize into GH2 and increase vessel pressure
Solution Approach 1:
The heat exchanger converts the harmful effect of heat transfer into a beneficial cooling process. Instead of heat accumulating in the liquid hydrogen and causing vaporization, the heat exchanger uses the temperature difference to actively remove heat from the liquid, converting what would be a harmful thermal input into a useful cooling mechanism that maintains liquid stability.
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 approach reduces the final vessel's temperature and saturation pressure, preserving colder liquid hydrogen for subsequent deliveries, minimizing venting, and improving operational efficiency by maintaining lower heat content in the system.
Implementation Method 1
using a centrifugal pump to transfer liquid hydrogen
Implementation Method 2
pressure equalization between the delivery tank and the final vessel, allowing gas to flow between the two to maintain pressure
Implementation Method 3
utilizing subcooling coils to remove heat from the final vessel
Implementation Method 4
Any heat introduced through the transfer/delivery processes or in the final vessel is absorbed by the liquid, which increases the temperature/saturation pressure of the cryogenic liquid
Data Source
AI summary
A cryogen storage vessel at an installation is filled with liquid cryogen from a liquid cryogen storage tank that has a pressure lower than that of the vessel. After headspaces of the vessel and tank are placed in fluid communication with another via a gas transfer vessel and are pressure-balanced, a pump in a liquid transfer line connected between the tank and the vessel is operated to transfer amounts of liquid cryogen from the tank to the vessel via the liquid transfer line and pump as amounts of gaseous cryogen are transferred, through displacement by the pumped cryogenic liquid, from the vessel to the tank.