05 December 2022
Classification society the American Bureau of Shipping (ABS) has granted Alfa Laval the first marine approval for methanol fuelled boiler. Alfa Laval received an Approval in Principle (AIP) on 4 November 2021. This was according to extensive solution testing at the Alfa Laval Test & Training Centre.
Methanol is liquid at ambient temperatures and carbon-neutral if produced from green sources. Thus, it is the next likely fuel step in decarbonising the marine industry. While methanol is already in use on a handful of vessels, its application so far is limited to main engines. In the future, methanol operations will need to extend to boilers.
“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. It was important for us to develop that approach, and we are proud to have it validated by ABS.”Lars Skytte Jørgensen, Vice President Technology Development, Energy Systems, Alfa Laval Marine Division
Alfa Laval has been testing boiler operations with methanol since early 2021 at the Test & Training Centre. Therefore, engine combustion tests with methanol are also underway. Using a pressure-atomizing MultiFlame burner to test 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.
Initially, results were obtained with both pure methanol and a methanol-water mixture. Thus, showed as expected that methanol is easy to ignite and results in very low emissions.
Therefore, the company focused 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 some adaptations. Hence, ensuring that a boiler can produce the same amount of steam regardless of which fuel is in use. This meant that the development could move rapidly to optimize the fuel supply system and work with ABS on the methanol AiP.
“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,”Vassilios Kroustallis, ABS Senior Vice President, Global Business Development.
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.
Meanwhile, Alfa Laval is pursuing wider optimisation possibilities that will compensate for methanol’s lower energy density and higher price. One of these is the use of an Alfa Laval Aalborg Micro economiser in conjunction with the OS-TCi. By absorbing waste heat from the boiler’s exhaust gas, the Aalborg Micro would recover valuable energy and reduce boiler-related fuel consumption by roughly 10%.
“Moving to methanol will require many changes on board, especially when it comes to energy management… The Aalborg Micro is a versatile boost in energy efficiency, suitable for the boiler and elsewhere. Together with other Alfa Laval solutions in development, it will help vessels fulfil energy needs while minimizing the methanol they consume.”Lars Skytte Jørgensen, Vice President Technology Development, Energy Systems, Alfa Laval Marine Division
Source: Alfa Laval