MHI tests 100 kW class cryogenic ORC power generation using oilless cryogenic turbine generator

Mitsubishi Heavy Industries (MHI) and Mitsubishi Heavy Industries Marine Machinery and Equipment (MHI-MME), a wholly-owned operating company of MHI, have conducted demonstration testing of 100 kW class cryogenic ORC (organic rankine cycle) power generation using the world’s first next-generation oilless cryogenic turbine generator.

The company said the testing demonstrated that with the use of liquid nitrogen as the cryogenic energy source it is possible to secure a stable refrigerant cycle and the specified regeneration output without freezing-induced clogging, etc., even under conditions more severe than the low temperatures of conventional liquefied natural gas (LNG) cryogenic generation.

In the demonstration testing, cryogenic power generation was performed by an intermediate fluid using a rankine cycle using cryogenic energy. Besides using liquid nitrogen in place of the conventionally adopted LNG, the test simulated actual LNG vaporisation equipment such as a marine fuel gas supply system (FGSS) and offshore/onshore LNG vaporisation equipment.

MHI noted 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.

The results suggested the potential for further stabilisation and reliability in LNG refrigerant generation systems and backed expectations of the use of hydrogen, seen as a promising decarbonised fuel, for cryogenic power generation.

According to MHI, the innovative generator adapts the turbine generator featuring a hermetically sealed oilless structure, of the kind used in ORC generation, to cryogenic power generation.

The ORC turbine generator, developed in-house, applying MHI Group’s turbine and cryo-temperature technologies, adopts oilless magnetic bearings and a hermetically sealed structure that prevents refrigerant leakage outside the system, MHI explained.

The company added that the 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 to the turbine structure used in earlier LNG-cooled power generation (steam turbines with open-end type, featuring forced-lubricated sleeve bearings).

MHi further said that the development of a next-generation turbine generator by MHI and MHI-MME will contribute to the creation of a new power generation business, making effective use of unused refrigeration heat and waste heat, adding it will pursue further development of solutions that will contribute to the reduction of greenhouse gas emissions and the protection of the environment.

As part of its initiative to look into a variety of clean energy solutions, in September 2022, MHI signed an agreement with Indonesia’s Institut Teknologi Bandung (ITB) to conduct joint research and development of ammonia-fired power generation by a gas turbine.