Ship Cargo Tank Segmentation for High-Pressure Discharge
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Solution Overview
Problem
The existing configuration for discharging liquefied gas from a ship requires both the pump and tank to have high pressure capacity, leading to increased costs and restricted tank size due to the need for enhanced pressure resistance.
Innovation Solution
A ship design featuring a main tank with low pressure resistance and a smaller sub tank with high pressure resistance, connected by a pipe system that includes a vaporizer to generate cargo gas, allowing for efficient transfer and discharge of cargo liquid using the pressure from the sub tank, thereby reducing the pressure burden on the main tank and pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressure capacity of the tank or pump is increased to handle high-pressure liquefied gas, then the discharge capability is improved, but the cost increases and tank size is restricted
Solution Approach 1:
The cargo tank system is segmented into a main tank for bulk storage and a sub-tank for pressure management and discharge operations. The sub-tank acts as an intermediate chamber that receives cargo from the main tank and handles the high-pressure discharge to external facilities, thereby protecting the main tank from high-pressure requirements while maintaining discharge capability.
Solution Approach 2:
The sub-tank serves as an intermediary between the main tank and external discharge facilities. It receives cargo liquid from the main tank via a transfer line and then discharges it to external facilities through a discharge line, absorbing the pressure stress and protecting the main tank structure from high-pressure demands.
2Productivity
If the pressure capacity of the tank or pump is increased to handle high-pressure liquefied gas, then the discharge capability is improved, but the tank size is restricted
Solution Approach 1:
The cargo tank system is segmented into a main tank for bulk storage and a sub-tank for pressure management and discharge operations. The sub-tank acts as an intermediate chamber that receives cargo from the main tank and handles the high-pressure discharge to external facilities, thereby protecting the main tank from high-pressure requirements while maintaining discharge capability.
Solution Approach 2:
The sub-tank serves as an intermediary between the main tank and external discharge facilities. It receives cargo liquid from the main tank via a transfer line and then discharges it to external facilities through a discharge line, absorbing the pressure stress and protecting the main tank structure from high-pressure demands.
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 enables an increase in tank size while maintaining cost-effectiveness by utilizing the sub tank's high pressure resistance and reducing the pumping capacity requirements, allowing for efficient discharge of cargo liquid without the need for high-pressure pumping.
Implementation Method 1
The vaporizer evaporates a cargo liquid, which is a liquid phase of the cargo, to generate a cargo gas
Implementation Method 2
A pressurizing line connects an upper portion in the sub tank and an upper portion in the main tank and pressurizes an inside of the main tank by pressure in the sub tank
Data Source
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AI summary
A ship comprising: a hull having a pair of broadsides; a main tank provided inside the hull and storing liquid or gaseous cargo; a sub-tank that has less capacity than the main tank and has greater pressure resistance than the main tank; a transport line that is connected to the sub-tank and has a section for connection to outside the ship; a first line connecting the main tank and the sub-tank; a second line connecting the main tank and the sub-tank; a vaporizer that, out of the first line and the second line, is provided only in the second line, vaporizes cargo liquid which is a liquid phase of the cargo, and generates a cargo gas; and a pumping unit that selects either the first line or the second line and pumps the cargo liquid from the main tank to the sub-tank.