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Description
The growing demand for cleaner and more efficient fuel solutions in the maritime industry has caused an increased adoption of liquefied natural gas (LNG) as a primary fuel source. To support this transition, a high-performance submerged electrical centrifugal LNG fuel pump has been developed to meet the stringent operational and safety requirements of this industry. The design of a two-stage centrifugal pump tailored for maritime applications has undergone comprehensive Finite Element Analysis (FEA) and extensive testing to validate its structural integrity.
The pump features an inducer, two-stage impeller with diffuser, and volute design, optimizing its hydraulic performance to ensure stable operation across a wide range of flow capacities. An inducer significantly enhances the pump’s ability to handle low suction pressure, reducing the risk of cavitation and ensuring reliable fuel delivery even in challenging operational profiles. The volute design further improves efficiency by maintaining a smooth and controlled flow path, minimizing energy losses while maximizing head generation.
Designed to be fully submerged in LNG, the pump is housed within a cryostat and vacuum insulated to efficiently minimize heat ingress and maintain the LNG at the required temperature. This insulation technology also extends the operation lifespan by reducing thermal stresses on critical components. The pump's electrical components have been engineered to function efficiently within the cryogenic environment, utilizing materials and insulation systems that maintain electrical integrity at extremely low temperatures. The electric motor with a power rating of 25kW is designed for submersion in liquid gas and cooling by the pumped medium. In addition, the pump is designed with a lubrication system using the cryogenic medium.
Extensive testing has been conducted to validate the pump's durability and reliability. An in-house test facility was constructed for using liquid nitrogen (LIN) as the cryogenic test medium. The pump underwent more than 300 hours of continuous operation under representative working conditions and about 2000 start-stop cycles representing real-world use. These tests demonstrated the capability to withstand repeated thermal cycling and mechanical stresses without performance degradation, thereby ensuring long-term operational reliability.
This LNG fuel pump has been designed for seamless integration into a range of maritime fuel supply systems. Its compact and integrated design allows for easy installation and facilitates service and maintenance. The pump has achieved DNV certification for compliance with safety, environmental and performance standards, confirming that it is fit for use in LNG-fueled marine propulsion and auxiliary systems.
Future developments will explore further optimizations in motor performance, insulation technology, material selection, component design, and filtration and purification systems for managing impurities, contaminants, and particular matter in liquified gas. In addition, aspects such as pressure stabilization mechanisms and reliquefication systems may be incorporated to handle fluctuating demands and requirements for minimal fuel loss and increased efficiency, which will follow with the increasing interest in LNG as a fuel source in the shipping industry.
Given the growing adoption of LNG in maritime propulsion, designing reliable and high-performance cryogenic fuel pumps is critical for the industry. This two-stage, inducer-equipped, volute-designed centrifugal pump represents a significant advancement in cryogenic pumping technology, offering a solution that meets the demanding requirements of the marine market for LNG-powered vessels.
