Ship LPG Return System With Cooled Recirculation Tank Control
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Solution Overview
Problem
Existing combustion engines face challenges in efficiently recycling liquefied petroleum gas without causing flash gas formation, solidification of oil content, and high energy consumption in recirculation systems, particularly when using ammonia as a fuel.
Innovation Solution
A return system incorporating a recovery device with a cooling mechanism, a recirculation tank, and a control system to manage fluid flow and pressure, ensuring efficient reuse of recirculated gas by cooling and storing it in a recirculation tank, and controlling fluid flow to minimize energy consumption and prevent solidification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recirculation flows are cooled down to prevent flash gas formation and oil solidification, then the quality of recirculated fuel gas is improved, but energy consumption increases due to cooling requirements
Solution Approach 1:
The patent combines the cooling device with the recovery device into an integrated system. The cooling device is positioned within the recovery device to cool recirculation flows during the recovery process, allowing simultaneous cooling and fuel gas recovery without requiring separate energy-intensive cooling systems. This merging reduces overall energy consumption while maintaining fuel gas quality.
Solution Approach 2:
The system uses the recirculation flows themselves as the cooling medium. The recirculation flows are cooled by exchanging heat with incoming fuel gas or ambient environment, and the cooled flows are then reused in the recirculation process. This self-service approach eliminates the need for external cooling systems and reduces energy consumption.
2Reliability
If recirculation flows are cooled to prevent oil solidification, then system reliability is improved, but flash gas formation may occur due to temperature and pressure changes
Solution Approach 1:
The patent carefully controls temperature and pressure parameters during the cooling and recovery process. The cooling device operates within specific temperature ranges that prevent oil solidification while avoiding conditions that would cause flash gas formation. Pressure is maintained within limits that prevent sudden phase changes. These parameter changes are monitored and adjusted to balance preventing oil solidification with avoiding flash gas.
Solution Approach 2:
The system incorporates monitoring of temperature, pressure, and flow conditions to provide feedback control. Sensors detect conditions that may lead to flash gas formation or oil solidification, and the control system adjusts cooling rates and pressure settings accordingly. This feedback mechanism ensures that the recirculation flows are cooled sufficiently to prevent oil solidification while maintaining conditions that avoid flash gas formation.
3Quantity of substance
If a recirculation tank is used to collect and separate fuel gas, then fuel gas retention is improved, but system complexity increases due to additional components
Solution Approach 1:
The recirculation tank is designed to perform multiple functions: it collects recirculation flows, separates fuel gas from other components, stores fuel gas, and maintains system pressure. By making the tank multi-functional, the patent reduces the need for separate dedicated components for each function, thereby improving fuel gas retention while minimizing the increase in system complexity.
Solution Approach 2:
The recirculation tank is designed with internal segmentation or zoning to separate different phases and components. The tank includes regions for liquid recirculation flows, vapor fuel gas collection, and separation zones. This segmentation allows efficient fuel gas retention and separation while maintaining a compact, integrated tank design rather than requiring multiple separate vessels.
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
The system maximizes the retention of ammonia or fuel gas, reduces energy consumption, and prevents oil solidification, ensuring efficient operation and cost-effective management of recirculated liquefied petroleum gas.
Implementation Method 1
a cooling device which is configured to cool the recirculation flow supplied by the main engine and/or auxiliary engine
Implementation Method 2
the recirculation tank is operated at a lower pressure level than the recovery device and below the saturation pressure associated with the saturation temperature so that so-called flash gas is produced in the recirculation tank
Data Source
AI summary
The invention relates to a return system (2) for returning recirculated propulsion liquefied petroleum gas, in particular, recirculated propulsion liquefied petroleum gas of a main engine (4) and/or auxiliary engine (6) of a ship (100).According to the invention, it is proposed that the return system (2) comprises a recovery device (8), wherein the recovery device (8) is connected by a supply line (10a, 10b) to a main engine (4) or an auxiliary engine (6) in a fluid-conducting manner and comprises a cooling device (26) which is configured to cool the recirculation flow (12a, 12b) supplied by the main engine (4) and/or the auxiliary engine (6), a gas supply system (14), which is configured to supply propulsion liquefied petroleum gas to the main engine (4) or the auxiliary engine (6), wherein the gas supply system (14) is connected to the recovery device (8) via a recirculation line (16) in a in a fluid-conducting manner and wherein a control valve (18) is assigned to the recirculation line (16) for setting a fluid flow through the recirculation line (16), and a recirculation tank (20), which is connected via an inlet line (22) is connected to the recovery device (8) and via an outlet line (24) to the gas supply system (14).