On board CCS

ONBOARD CCS TECH LIKELY TO USE OPEN-SOURCE SOLVENTS

Wärtsilä is taking a central role in developing maritime carbon capture & storage (CCS) technologies and says it will most likely rely on generic solvents to facilitate worldwide availability for shipowners

Sigurd Jenssen, Director at Wärtsilä Exhaust Treatment, says that the company’s on-going testing of a 1MW landbased system at its research centre in Moss, Norway, demonstrates good performance without the need to replenish the solvent after fi ve months. “We are not seeing any signifi cant solvent degradation, but we don't really know yet how long the solvent will last or how big a OPEX component it will be. So far it looks very, very promising that the degradation is quite slow.”

The system being developed works for the exhaust of any fuel containing carbon, including HFO, diesel and LNG. “As long as you have CO2 in the exhaust, we know we can capture it,” says Jenssen.

Depending on the fuel, there will be different forms of pretreatment, because SOx, NOx and particulate matter should be removed as much as possible before the carbon capture process. The exhaust gas also needs to be cooled, as the process works optimally between 30 and 40 degrees Celsius.

A standard scrubber is used to remove the pollutants, and an absorber containing the solvent then removes the CO2 which is stripped off in a second part of the system and then liquified for storage. The system operates as a closed loop for the solvent. “We are first and foremost equipment suppliers, so we don’t plan on developing our own solvent. We are looking at open-source supply, so shipowners can source it anywhere in the world, but we are also looking at qualifying proprietary solvents. There’s a number out there from the bigger oil and chemical companies, so we will test those to make sure that they work within our system.”

With the equipment design already scoped out and ready for scaling, testing is part of the ongoing research being conducted by Wärtsilä along with determining the optimal pressures and temperatures required.

Wärtsilä Exhaust Treatment and the Norwegian shipping company Solvang have agreed on a full-scale pilot retrofit installation on Solvang’s 21,000cbm ethylene carrier Clipper Eos. The companies expect to retrofit the pilot CCS system on the Clipper Eos by 2023. The vessel has a 7MW main engine, and Jenssen is confident about up-scaling and marinizing the technology. “We don't expect problems; we have done this in the past.

“A key element to making sure this is a good solution is to recover as much of the energy as possible from the ship because the capture process requires electricity and heat. Heat recovery is one of the advantages with the process that we have chosen. Getting hold of that waste heat and utilizing it for something sensible is better than just letting it go overboard either with the exhaust or with coolant water.”

Wärtsilä aims to have a system about the same size as a SOx scrubber that will capture 70% of the CO2 in the exhaust gas. This figure also matches IMO decarbonisation targets for 2050, and would require roughly 10% of engine power to operate.

Every tonne of fuel burnt, generates approximately three tonnes of CO2. As the density of liquid CO2 is 1.1, around 1,100 cubic meters of storage would be required for every tonne of CO2. The space for this is likely to be available on many tankers, but some cargo capacity may need to be sacrificed on bulkers and container vessels, says Jenssen, but he points to the larger storage tank requirements for new fuels such as hydrogen, or even LNG. He says Wärtsilä aims to make the space sacrifices as small as possible.

Jenssen estimates that the cost of capturing CO2 would be somewhere between 50 and 70 euros per tonne.

Wärtsilä is also partnering with the LINCCS consortium to scale and create carbon capture technologies and infrastructure. Last year, the consortium received 111 million Norwegian Kroner in funding for CCS research and development. The LINCCS project is focused on reducing costs for new carbon storage facilities by 70% and advancing the development of carbon capture technologies in a range of sectors. Other project partners include SINTEF, Aker Solutions, Aize, Cognite, Equinor, Lundin, TotalEnergies, Wintershall, and Vår Energi.

We are not seeing any significant solvent degradation, but we don't really ‘‘ know yet how long the solvent will last or how big a OPEX component it will be. So far it looks very, very promising that the degradation is quite slow

8 Sigurd Jenssen, Director at Wärtsilä Exhaust Treatment