Ship CO2 Loading Pipe Segmentation to Prevent Dry Ice
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Solution Overview
Problem
The challenge is to prevent the solidification of liquefied carbon dioxide into dry ice within the loading pipe during the loading process, which can obstruct the flow and affect the operation of the tank due to pressure differences and evaporation, especially since the triple point pressure of carbon dioxide is higher than that of LNG or LPG.
Innovation Solution
A ship design with a loading pipe system that includes an upper and lower loading pipe, along with on-off valves controlled by a detection system to manage the pressure and liquid level, ensuring that liquefied carbon dioxide is loaded through the upper pipe initially and then switched to the lower pipe once the liquid level reaches a certain height, maintaining pressure above the triple point pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the loading pipe extends from the top portion to the bottom portion of the tank, then the liquid head pressurization suppresses flash evaporation at the pipe opening, but the pressure at the pipe top portion decreases due to height difference, causing liquefied carbon dioxide to evaporate and potentially solidify into dry ice
Solution Approach 1:
The loading pipe is divided into multiple sections with different functions: a transport pipe for bulk transport, an upper loading pipe for initial loading, and a lower loading pipe for continued loading after liquid level rise. This segmentation allows each section to operate under optimal pressure conditions, preventing dry ice formation in the transport pipe while maintaining effective loading.
Solution Approach 2:
The system dynamically switches between the upper loading pipe and lower loading pipe based on the liquid level in the tank. When the liquid level rises above the lower loading pipe opening, the system transitions from using the upper pipe to the lower pipe, adapting to changing pressure conditions to prevent evaporation and solidification.
2Reliability
If the loading pipe opens to the lower portion of the tank, then the liquid head provides sufficient pressure to prevent flash evaporation, but the pipe top portion experiences pressure reduction that may cause solidification
Solution Approach 1:
The loading system is segmented into a transport pipe and a lower loading pipe that opens to the lower tank portion. The transport pipe delivers liquefied carbon dioxide to the tank region where liquid head pressure is sufficient to prevent flash evaporation and subsequent solidification, while the lower loading pipe ensures continued pressurization as the liquid level rises.
Solution Approach 2:
The lower loading pipe acts as an intermediary that maintains the pressure gradient necessary to prevent flash evaporation. By positioning the opening at the lower tank portion, it ensures that the discharged liquefied carbon dioxide immediately receives sufficient liquid head pressure, preventing the harmful solidification effect.
3Power
If the triple point pressure of carbon dioxide is close to the operating pressure of the tank, then the tank can operate at efficient pressure, but the pressure in the pipe top portion may drop to or below the triple point pressure, causing solidification
Solution Approach 1:
The system dynamically adapts to pressure changes by switching between upper and lower loading pipes. When operating at efficient pressures close to the triple point, the system uses the upper loading pipe initially, then transitions to the lower loading pipe as the liquid level rises, maintaining pressure above the triple point throughout the loading process.
Solution Approach 2:
The system changes the operational parameters by switching between different pipe configurations based on liquid level. This parameter change ensures that the pressure of liquefied carbon dioxide remains above the triple point pressure throughout the loading process, preventing solidification while maintaining efficient operation near the triple point.
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 effectively suppresses the generation of dry ice in the loading pipe, ensuring smooth tank operations by maintaining the pressure of liquefied carbon dioxide above its triple point pressure, preventing solidification and flow obstruction.
Implementation Method 1
the vicinity of the opening of the loading pipe is pressurized with an increase in liquid head
Implementation Method 2
flash evaporation of the liquefied gas discharged from the opening of the loading pipe
Implementation Method 3
the liquefied carbon dioxide evaporates, and due to the evaporation latent heat thereof, the temperature of the liquefied carbon dioxide remaining without evaporating is lowered
Implementation Method 4
the pressure of a triple point (hereinafter referred to as triple point pressure) at which a gas phase, a liquid phase, and a solid phase coexist
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
This ship includes a hull, a tank, and loading piping. The hull has a pair of ship sides. The tank is provided in the hull. The tank can store liquefied carbon dioxide. The loading piping loads liquefied carbon dioxide, supplied from the outside of the ship, into the tank. The loading piping includes transport piping, upper loading piping, lower loading piping, a first on-off valve, and a second on-off valve. The transport piping has a connection part connected to the outside of the ship. The transport piping extends into the hull. The upper loading piping branches off and extends from the transport piping. The upper loading piping opens at the upper part of the inside of the tank. The lower loading piping branches off and extends from the transport piping. The lower loading piping opens at the lower part of the inside of the tank. The first on-off valve is provided in the upper loading piping. The second on-off valve is provided in the lower loading piping.