MHI-MME successfully trials ORC waste heat recovery system with LN2

The tests demonstrated that the modified ORC system achieved a stable refrigerant cycle and the specified regeneration output without freezing-induced clogging using LN2 as the cryogenic energy source.

Innovative ORC

The new ORC turbine generator, developed in-house applying MHI Group’s comprehensive turbine and cryo-temperature technologies, adopts oilless magnetic bearings and a hermetically sealed structure that prevents refrigerant leakage outside the system. Improvements for refrigerant power generation were made based on the Company’s operating track record in ORC power generation, enabling higher reliability, space savings and maintenance-free operation compared with the turbine structure used in earlier LNG-cooled power generation (steam turbines with open-end type, featuring forced-lubricated sleeve bearings).

Demonstration

In the demonstration testing, which was conducted in January 2023 at MHI’s Research & Innovation Center in the Nagasaki District, cryogenic power generation was performed by an intermediate fluid using a Rankine Cycle using cryogenic energy. Besides using liquid nitrogen (boiling point: approx.-196℃) in place of the conventionally adopted LNG (boiling point: -160℃), the test simulated actual LNG vaporization equipment such as a marine FGSS (fuel gas supply system) and offshore/onshore LNG vaporisation equipment.

The testing provided useful results in terms of understanding the refrigerant cycle properties and the phase changes of cryo-temperature media such as LNG or liquid nitrogen, and also confirmed the system’s controllability. These results suggest the potential for further stabilization and reliability in LNG refrigerant generation systems, and also support expectations of the use of hydrogen (boiling point: approx. -253℃), seen as a promising decarbonized fuel, for cryogenic power generation.

The Motorship reported that MHI-MME had launched a new binary power generation system based on ORC technology in September 2022.