First reference installation of Opcon Waste Heat Recovery technology for ships; potential for 5–10% fuel savings
|The MV Figaro. Click to enlarge.|
Opcon, in collaboration with Wallenius Marine, recently completed the first reference installation of its Waste Heat Recovery technology for ocean-going vessels in a project supported by the Swedish Energy Agency. (Earlier post.) The company has now received official approval from Lloyd’s Register for use at sea.
The Opcon systems generate electricity from low-value waste heat in the vessel’s steam and cooling system. The aim is to save fuel while reducing emissions of CO2, NOx, sulfur and particles. For this first reference installation aboard the Large Car-Truck Carrier (LCTC) MV Figaro, IMO 9505041, fuel savings are expected to be around 4-6%, but the potential in other installations is 5-10%, according to Opcon.
|Opcon Powerbox ORC Marine version. Click to enlarge.|
The 227.8-meter (747-foot), 74,258 gross tonnage Figaro, bult by Daewoo Shipbuilding & Marine Engineering, can carry 7,879 cars or a combination of 3,508 cars and 432 buses. The main engine is a two-stroke MAN B&W 8S60ME-C8 electronically controlled directly reversible marine diesel with constant pressure supercharging and a maximum output of 19,040 kW (25,533 hp) at 105 rpm.
In a separate compartment of the engine room there are two 450 V, 60 Hz, 1,700 kW AC-generators installed each powered by a STX/MAN-B&W diesel engine, type 9SL21/31H. In addition the vessel is equipped with a 1,100 kW shaft generator and an emergency diesel generator with a capacity of 215 kW.
Behind this success lies some enormous hard work carried out to integrate these systems. This is a milestone in our efforts to adapt our pioneering technology for production of electricity from waste heat for use in marine applications. We will now fine-tune, test and verify the improvement in energy efficiency that this system offers in various operational scenarios at sea. By utilizing waste heat and recovering the energy, significant environmental gains can be made. Considering today’s oil prices and the efforts being made by the IMO, for example with the coming International Energy Efficiency Certificate (IEE), we believe that this product really has come at exactly the right time.—Rolf Hasselström, President and CEO of Opcon AB
Opcon has developed two marine versions of its Powerbox:
Opcon Powerbox ORC (Organic Rankine Cycle), which enables utilization of low-value heat such as hot water in a vessel’s cooling system. Waste heat is used by a heat exchanger to vaporize a working fluid with a boiling point lower than water. The gas expands over an expander, which drives a generator to produce electricity. The fluid is then cooled, and a pump increases its pressure to 30 bar, and circulates it back through the first heat exchanger.
The unit comprises a Lysholm turbine with a synchronous generator and auxiliary systems. The key factor in the ORC system is the reliable Lysholm turbine, developed by Opcon’s Svenska Rotor Maskiner (SRM).
Opcon Powerbox WST (Wet Steam Turbine) is a special type of steam turbine that generates electricity from wet steam (max 85% liquid), saturated steam or superheated steam (max 250 °C).
The unit comprises a Lysholm turbine with an asynchronous generator and auxiliary systems. The turbine unit receives saturated or wet steam up to 16 bar generated in an exhaust gas boiler connected to the main engine of the ship. The steam is expanded to a set pressure down to 0.2 bar.
|Opcon Powerbox WST Marine version. Click to enlarge.|
The first reference installation features both Opcon Powerbox ORC and Opcon Powerbox WST. The larger Opcon Powerbox ORC is powered by the vessel’s diesel cooling water and in this installation it can supply at most up to 500 kW. The smaller Opcon Powerbox WST is powered by surplus steam available on the vessel.
Opcon estimates that more than 1,000 newly built vessels a year as well as many existing vessels could benefit from Opcon Powerbox technology. The entire merchant shipping fleet is estimated to account for 4-5% of global emissions of CO2.
From a fuel-saving point-of-view, the energy that Opcon’s technology recycles from the ship engine’s cooling system and purge air cooler is the most important feature in this first reference installation, but there is also a large number of vessels for which steam applications will be of great interest, according to the company.