ABS grants approval in principle for firing boilers with methanol

MARITIME classification society the American Bureau of Shipping has granted Alfa Laval what it says is the first marine approval for operating boilers on methanol.

Alfa Laval received an approval in principle (AIP) on 4 November 2021, based on extensive solution testing at the Alfa Laval Test & Training Centre.

Alfa Laval said methanol, which is carbon-neutral if produced from green sources, is the next likely fuel step in decarbonising the marine industry. While methanol can be found on a handful of vessels and is planned for many more, its use has so far been limited to main engines. In the future, methanol operations will need to extend to boilers.

Alfa Laval Marine Division vice-president technology development, energy systems Lars Skytte Jørgensen said Alfa Laval is looking at the full scope of methanol’s influence on board.

“The most natural choice for boilers is to fire them with the vessel’s primary fuel, but methanol’s low-flashpoint nature and the differences in its energy density require a new approach to the burner and fuel supply systems,” Mr Jørgensen said.

“It was important for us to develop that approach, and we are proud to have it validated by ABS.”

 Alfa Laval has been testing boiler operations with methanol since early 2021 at the Alfa Laval Test & Training Centre, where engine combustion tests with methanol are also underway.

Tests have been conducted using a pressure-atomising MultiFlame burner on an Alfa Laval Aalborg OS-TCi boiler, as well as a methanol valve unit (MVU) designed by Alfa Laval to meet the class requirements from ABS.

Initial results, obtained with both pure methanol and a methanol-water mixture, showed as expected that methanol is easy to ignite and results in very low emissions. Focus was therefore placed on securing the same steam output with methanol – despite its lower heat value – as would be the case using oil or gas as fuel.

A solution was reached after a few adaptations, ensuing that a boiler of a given size can produce the same amount of steam regardless which fuel is used. This meant that development could move rapidly to optimizing the fuel supply system and working with ABS on the methanol AIP.

 ABS senior vice-president, global business development Vassilios Kroustallis said ABS is a leader in maritime sustainability and supporting the industry’s move to alternative fuels like methanol is a high priority.

“We are proud to partner with Alfa Laval and support this pioneering industry development,” he said.

With the AIP in hand, the next step for Alfa Laval will be a pilot installation on an oceangoing vessel. Results from field testing will be crucial in fine-tuning the methanol boiler solution and arriving at a commercial design.