What are better scrubbers or low-sulfur fuels?

It is a well-known fact that the Marine Environment Protection Committee (MEPC) confirmed that the sulfur content in marine fuel should be at least 0.5% by January 1, 2020. Thus, shipowners have two options: to install air treatment devices on their ships or use fuel with low sulfur content.

So what is better – the installation of scrubber systems or the use of LS fuel (with 0.5% sulfur content)?


Shipowners face a difficult choice that requires several factors to be considered:

  • Fuel consumption;
  • Age of the vessel;
  • Time that the ship spends at sea;
  • Navigation area of the vessel;
  • How much space is available on the ship;
  • How much free power is available for additional equipment on the ship;
  • What type of agreement is used with the charter.


Fuel consumption

First of all, it is necessary to pay careful attention to fuel consumption. The owner of a large ship with a large fuel consumption needs to think carefully because he needs to calculate how much the ship uses high sulfur fuel per year, how much does it cost, how much low sulfur fuel will be needed per year, and calculate the difference in money. And then it is recommended to think about whether it will be more profitable to put a scrubber or better to apply LS fuel.


Age of the vessel

Age is also an important factor. Does it make sense to install an expensive system if the ship is going to be sold for scrap soon? Sometimes it is more profitable to build a new vessel with an already installed air treatment system for air pollution control than to maintain the old one according to new requirements.


Navigation area

Air pollution control of exhaust gases will only be performed in ports and the ECA (Emission Control Areas). This means that a large vessel that is located outside these areas for most time can use high sulfur fuel, therefore, it is more profitable to install a scrubber or use a hybrid system.


Installation place of the air treatment system

Each ship is unique. Passenger ships install a scrubber right in the exhaust pipe. Large bulk carriers and tankers can easily install the air treatment system both in the exhaust pipe and make an extension to it. For example, on tankers, most of the equipment is installed on the deck, instead of the engine room.


Where do ships get the power from?

The new scrubber system requires more ship power. Taking into consideration the fact that there are also requirements for the ballast system, most ships will not have enough power, that is why they put an additional generator. The additional generator means more fuel consumption, more supplies, more maintenance, and more responsibilities for the crew.


What about the charter?

The fact is that it takes about a month to install the scrubber. The ship maintenance during one month in the dock is a large minus for the shipowner and an extra headache for the charter.


What if you choose LS fuel?

To begin with, fuel tanks, fuel handling equipment, and pipes must be drained and treated from HS fuel so that it does not mix. It is difficult to imagine how much time the process will take and how long the ship will stay at the pier just for this reason.

Burning distillate fuel can lead to problems with the fuel pumps, which will cause excessive wear and scratches, as well as damage to the old engine.

Moreover, its price will increase because of the increased demand for LS fuel. From this point of view, the vessels with scrubbers will win financially.


And if you choose the scrubber?

The market offers a huge number of wet air scrubbers for air treatment, i.e. they use seawater to clean exhaust gases. These wet scrubbers are divided by the appearance: open and closed-loop, hybrid, built-in, attached type (U-type) scrubber systems.

Open-loop wet air scrubbers are suitable for vessels operating in open seas. The scrubber system takes water and pumps it through the scrubber, treating most of the sulfur from the exhaust, and then discharges the water overboard (mostly without polluting the environment).

The closed-loop scrubbers are ideal for vessels that sail in the ECA areas or frequently enter ports. The operation of this system is similar to an open cycle, only the water does not go overboard, but remains on the ship. Later, the resulting sludge is removed at a suitable port.

The hybrid scrubber system is more expensive, it combines an open and closed type, which is more convenient and economical if you look at the promising future.

Built-in wet scrubbers are installed in the main engine along with the exhaust pipe. They are often used on passenger and container ships.

U-type air treatment systems have become very popular, as they can be attached to the exhaust pipe and do not require its redevelopment. This type is installed faster than the built-in one since the installation is designed and created in advance.

The shipowner will have to go through many stages before the wet air scrubber is installed. It is necessary to choose the type of scrubber, manufacturer, which directly affects the price, delivery, and installation time.

The full installation of the open-loop wet air scrubbers varies between 3-6 million dollars. Delivery of all equipment takes from 7 months to 2 years. The price and delivery time of wet scrubbers increases due to the huge number of orders.

The next problem is to find a manufacturer in a suitable area with the opportunity to store a ship and assemble this system at a favorable price and in the shortest possible time. The shortest time to build this system is 35-40 days.

The availability of manufacturers due to the influx of people who want to install scrubbers for air pollution control is already a problem. Don’t forget that the IMO also requires installing ballast tank cleaners. For example, it is known that several Chinese factories reported that their schedule for 2019 is full.

The scrubber system must pass a series of checks and receive a certificate after its installation. The crew must take additional courses. And by the way, do not forget that ship mechanics will have more work that no one will pay for besides.

However, it has been found that scrubbers have less impact on the climate than low-sulfur fuels. 

For instance, an independent environmental research consulting company has published a new study that concludes that the use of wet air scrubbers leads to slightly lower CO2 emissions compared to the use of very low-sulfur fuels on several ships.

Previous studies have shown uncertain results regarding the environmental impact of using scrubbers, especially on what environmental impact matters, how large the impact is, and how it should be evaluated.

The new study provides a comprehensive overview of the climate impact of various options for reducing sulfur emissions. It shows that in many cases the carbon footprint from applying a scrubber is lower than using low-sulfur fuels.

The thing is that wet scrubbing systems remain the most commonly used air treatment devices that allow performing air pollution controlIf you search for the best air treatment device to improve air quality, you can buy a high-tech completely new type of wet scrubber – a Multi-Vortex wet air scrubber produced by Redwood Technology.

Redwood technology is a fast-growing vendor of wet air scrubbers. The multi-vortex scrubber can remove gas emissions, dust, vapors, and other pollutants from a gas stream. It is an innovative technology created to save water that makes it more cost-efficient and differs from other types of scrubbers.  If you have any questions or would like to purchase a multi-vortex wet air scrubber, please contact us at info@rdwd.tech

Leave a Reply

Your email address will not be published.