Langh Ship Develops Exhaust Gas Scrubber
Although the sulphur limit for ship fuel in the North Sea and Baltic Sea is 1%, Langh Ship’s m/s Laura sails in the area with whatever fuel the charterer has found in Rotterdam, no matter how high its sulphur content. This is possible because the shipping company has equipped the vessel with a closed loop scrubber that emits exhaust gas that is even cleaner than if the fuel had a sulphur content of no more than 0.1%.
Environmental regulations in this sulphur emission control area (SECA) have been tightened such that the sulphur limit for fuel will drop to 0.1% at the start of 2015. “In practice, this means that ships will have to switch to diesel, i.e. marine gas oil (MGO), unless they are equipped with exhaust scrubbers,” explains the shipping company’s Managing Director, Hans Langh. The difference in price between MGO and the low sulphur heavy fuel oil currently being used in the area is more than 300 USD per tonne, bringing a major increase in shipping costs.
Hans Langh says the company started looking into various options early on: “We requested quotations on scrubbers, but the offers we were getting were just too high to seriously consider installing them in used vessels.”
The challenge in installing exhaust scrubbers in ships, especially when it comes to retrofitting, is the lack of space. Another problem appeared to be cleaning of the emission washing water used in the scrubber.
Genuine closed loop system
Legislation allows the use of seawater in scrubbers such that instead of emission impurities being released into the air, they are discharged into the sea (i.e. open loop scrubber). “For us, however, it was important that our scrubber be based on a closed loop system, whereby the requirement is for the washing waters used in the process to be cleaned so as to separate the harmful substances,” explains Reino Verosaari, Langh Ship’s Senior Technical Adviser.
Hans Langh has extensive expertise in water treatment, as another of his family-owned companies – Industrial and Ship Cleaning Services Hans Langh – has 40 years’ experience in cleaning washing waters. This expertise served as the foundation when the company set off to develop a scrubber and washing water processing system for its ship.
And the development work paid off: while m/s Laura was docked in May, a scrubber was installed in the vessel and test runs have been carried out since then. And, upon being granted special permission from the Finnish Transport Safety Agency Trafi, high sulphur fuels have been tested, too. The results are encouraging: the exhaust gas is cleaned in line with the requirements of the upcoming regulations, and the washing waters used in the method are also cleaned. In addition, the cleaning system removes particulates from the exhaust gas, even though this is not required by legislation. The system is protected by multiple patent applications.
“We would never have been able to accomplish this without the participation of Tekes, the Finnish Funding Agency for Technology and Innovation. We put in a tremendous amount of effort into conducting research and developing and testing methods, and the support and funding we received from Tekes was crucial in that respect,” says Langh. After first building a small-scale model of the scrubber and conducting the ship’s exhaust gases to it, the cleaning of the washing water was tested using various methods. The project was started up in 2012, and now the results are in.
The scrubber is literally out of sight
“Our goal was to create a scrubber that would change the ship’s properties as little as possible and barely affect its cargo capacity,” explains Langh Ship’s Commercial Manager, Laura Langh-Lagerlöf, who was highly involved in the development team. “And on m/s Laura, we really hit the nail on the head – you can’t even see the scrubber from the outside.”
Since the scrubber does not result in any new projections from the ship, nor does the vessel’s centre of gravity change as a result of the scrubber, its sailing characteristics remain the same. The efficiency of the installation is further increased by the fact that the increase in weight is very small. The washing water cleaning system additionally ensures that on board storage of the waste destined for land does not actually reduce the vessel’s cargo capacity.
Langh Ship is planning to install scrubbers in its four other vessels. The method will also be made available to others: “This has been such a success that we believe others may be interested in it too,” says a pleased Langh-Lagerlöf.