SPIRETH - Methanol as marine fuel
The main goal of the SPIRETH (“Alcohol (spirits) and ethers as marine fuel”) project was to test methanol-based fuels in a full scale pilot project, to contribute to finding the best environmental and economic alternative for a sustainable and successful maritime transport industry.
The project focused on two concepts for using methanol fuel on board as follows:
- DME: Development of a methanol to DME conversion process plant for shipboard operation, and testing the plant and the DME fuel mix on board an existing ship, using an adapted diesel auxiliary engine. Methanol was loaded and stored on the ship, and converted using the Haldor Topsøe OBATETM (On board alcohol to ether) process.
- Methanol: Conversion of a full scale marine diesel engine to run efficiently on methanol with pilot fuel ignition, and performance testing in a laboratory.
The project began in 2012 and testing was completed in 2014. For the DME fuel concept, work carried out included the design, installation, and operation of an OBATETM (On Board Alcohol to Ether) process unit for dehydrating methanol to a fuel mix of DME (60% by weight), water, and methanol. The unit was tested on-board the Stena Scanrail, a ro-pax ferry that sailed between Gothenburg and Frederikshavn.
For the methanol engine conversion part of the project, a retrofit solution was developed for conversion of a ship’s main diesel engine to methanol operation. Low emissions, high efficiency, robust solution and cost effective conversion were key factors considered when evaluating the different combustion concepts and design solutions. Diesel combustion of methanol with pilot fuel ignition was determined to be the preferred combustion retrofit concept. A full scale engine was converted and tested in a laboratory with good results regarding efficiency and reduced emissions of NOx and particulate matter as compared to conventional diesel fuel. SOx emissions were very low because methanol does not contain sulphur and the only contribution was from the pilot fuel used for ignition.
The SPIRETH project work showed that methanol and DME-based fuels are viable alternatives for reducing emissions from ships. Risk and safety analysis work carried out in the project contributed to the development of ship classification society rules for methanol as a ship fuel and to the International Maritime Organization’s draft IGF code (International Code of Safety for Ships using Gases or Other Low-Flashpoint Fuels). The work also led to a full scale methanol ship conversion project by project partner Stena.
The SPIRETH project group consisted of SSPA Sweden (project coordinator), ScandinNAOS (technical coordinator), Stena Rederi, Haldor-Topsøe, Wärtsilä, Lloyd’s Register EMEA, and Methanex.
SPIRETH was co-financed by the Swedish Energy Agency, the Baltic Sea Action Plan Facility Fund (Nordic Investment Bank), the Nordic Council of Ministers’ Energy & Transport Programme, and the Danish Maritime Fund, and the project partners.