State-of-the-art marine Waste Heat Recovery Organic Rankine Cycle

A new state-of-the-art binary power generation system based on Organic Rankine Cycle technology (WHR-ORC system) has been developed for marine waste heat recovery from sulphur free fuel burning engines, which are becoming mainstream in the transition to a low-carbon and decarbonized society. It consists of three models that cover rated outputs of between 200kW and 700kW and is capable of being used on a wide range of vessel types.

The Waste Heat Recovery Organic Rankine Cycle (WHR-ORC) system is claimed as the most advanced waste heat recovery system with high thermal efficiency characterized as oil-free, fully sealed, and maintenance-free. It was developed by combining marine waste heat recovery system, which includes waste gas economizer, steam turbine, and power turbine (gas turbine), with centrifugal chilling technology. In the future, it is expected to achieve high efficiency and energy-saving in engines powered by carbon-free fuels such as hydrogen and ammonia as well as by carbon-neutral fuels, including biomethane and bio-methanol.

It is thought, based on manufacturer’s literature, that the centrifugal technology uses non-flammable R-245fa (boiling point 15.3°C) as the working fluid for the Organic Rankine Cycle. However, HCFO-1233zd(E) (b.pt. 18.3°C) has similar properties to HFC-245fa and can also be used for ORC systems.

Source: Hellenic Shipping News and manufacture’s information.

Explanatory Note: Particularly in maritime industry, according to International Maritime Organization (IMO) and International Convention for the Safety of Life at Sea (SOLAS) regulations, the flash point of fluid in the machinery space shall not be lower than 60°C, which dictates the choice of working fluids for the ORC system, and which means that none of the hydrocarbons can be considered as the working fluid. Between 2007 and 2012, shipping had 2.8% share of global GHG emissions, therefore, current studies focus on increasing energy efficiency, reducing costs and emissions. One of the most promising technologies for fulfilling the requirements is Organic Rankine Cycle (ORC). See: An investigation of marine waste heat recovery system based on Organic Rankine Cycle under various engine operating conditions, M. Akman and S. Ergin, Proc IMechE Part M:J Engineering for the Maritime Environment 2019, Vol. 233(2) 586–601, DOI: 10.1177/1475090218770947

More information about Organic Rankine Cycle fluids is available on the fluorocarbons website.

 

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