Scrubber experts relayed their experience of retrofit installation, wastewater monitoring and lowering the closed-loop scrubber carbon footprint during the Marine Air Pollution, Europe conference during a session sponsored by Yara Marine Technologies
Exhaust Gas Cleaning System Association director Don Gregory set the background for the discussion, saying some potential opportunities for incremental greenhouse gas (GHG) emissions reductions were being overlooked.
“It is increasingly evident that was a major oversight by shipowners and charterers alike. Again, the (shipping) industry is on the back foot and failed to consider the incremental reduction in CO2 on a well-to-wake basis,” he said.
The evidence in the CE Delft report Comparisons of CO2 emissions of Marpol Annex VI compliance options in 2020 shows that sulphur cap-compliant fuels have a higher well-to-wake CO2 footprint than scrubbers, though both compliance methods ultimately increase overall CO2 while abating sulphur emissions.
Shipping has also become a target for unilateral action by the EU, which is bringing the industry into the European Emissions Trading System (ETS).
The inclusion of shipping into the CO2 pricing system of the ETS will “hopefully encourage shipowners and charterers to consider more holistically the impact of their IMO 2020 compliance choices,” Mr Gregory said.
What to look for in a successful scrubber retrofit
With his company’s 10 years of experience and more than 400 scrubber installations, Yara Maritime Technologies sales and public affairs director Kai Latun presented a case study of an open-loop retrofit installation offering attendees a look at the details of a successful, certified and operational installation.
“A typical installation is now 14 days,” he said. The installation took place in Yiu Lian Shekou shipyard in China, and the scrubbers were assembled in China with material from Europe or the USA. “This is to make sure we have the right quality high nickel alloys.”
The first stage is the engineering and procurement, which takes 22 weeks before installation. This stage requires all the design data, 3D scans, exact dimensions of equipment including the exhaust pipe diameter. The success of the projects rests on engaging with the project integrator and the yard and agreement on the plan. Yara’s representative noted that careful attention must be paid to the six Ps: ’Proper planning prevents poor project performance’.
In this case, the project benefited from having three Yara Marine Technologies engineers on site alongside an owner’s representative. Mr Latun noted that shipyards in China have become very proficient in scrubber and ballast water treatment system installation, which are often conducted in tandem, but that sometimes a yard will want to simplify an installation to save time. These shortcuts may manifest as operational issues at sea and he warned it is necessary to have people on site to manage the project, deal with contingencies and push-back against short-term remedies.
Regarding contingencies, he noted that often the same parts are mislaid by the yard or damaged. “We bring along spares to cover this,” he said. Special attention must be given to the wash water outlet, he said. The wash water is corrosive, which is why Yara specifies a protective surface on the hull in the area of the outlet, and the outlet is away from any intakes.
Questions about open-loop scrubber wash water
Wash water was the topic tackled by monitoring system provider Chelsea Technologies head of sales and marketing Matthew Kenney. Chelsea Technologies is the provider of the Sea Sentry IMO-compliant wash water monitoring system. He noted that around 80% of scrubbers in use are open loop, meaning that seawater is pumped into the gas desulphurisation unit and back out to sea.
“The whole issue of waste water is poised to be a more pressing issue throughout 2021,” he said. This is because the rules have not been set and “Wash water rules are sitting in the awkward guidelines space as an annex to the main regulations,” he said.
IMO rules and guidelines on wash water are drafted by the Pollution Prevention and Response sub-committee, which undertakes the work on behalf of the Marine Environment Protection Committee (MEPC). This is the body that ratifies regulations.
The key takeaway, noted Mr Kenney, is that revised guidelines for wash water, known as 2020 EGCS Guidelines are likely to be approved at MEPC 75 and come into force in May 2021.
The second key point Mr Kenney presented was the outcome of the findings of a joint group of experts on the scientific aspects of marine environmental protection, known as GESAMP. The findings were inconclusive and it is likely that further studies will be undertaken. The long-term outcome, according to Mr Kenney, is that wash water will have a greater focus at IMO, pointing toward an increase in scrutiny and stricter requirements for wash water monitoring.
Reducing fuel consumption and emissions with chemistry
Around 80% of installed scrubbers are open loop, but the remaining 20% are closed loop and hybrid types that are not using seawater and need a source of alkali. Europiren managing director Henk Don explained how his company’s natural product, derived from brucite which is a mineral form of magnesium hydroxide, could significantly lower the carbon footprint of closed and hybrid scrubbers.
In closed-loop mode, the most commonly used alkali is caustic soda, magnesium hydroxide or magnesium oxide. The advantage of using magnesium hydroxide (Brucite) is the theoretical lower fuel consumption. For a 10-MW engine consuming an average of 15 tonnes of 3.5% HSFO, the theoretical alkali consumption is: Caustic soda – 58 kg per tonne of fuel, Magnesium hydroxide – 44 kg per tonne of fuel, Magnesium hydroxide (Brucite) – 30 kg per tonne of fuel.
Magnesium hydroxide (Brucite) is a powder and needs to hydrate into a slurry. Mr Don noted that slurry-making facilities are readily available, close to most major ports. However, magnesium hydroxide is divalent, which means it only takes one ion to capture sulphur, whereas caustic soda requires two: magnesium hydroxide is more efficient in capturing sulphur.
Another important point, according to Mr Don, is that magnesium hydroxide reaches a maximum alkali of 10 pH, which is not classed as hazardous. Caustic soda reaches an alkali of 14 pH, which is harmful to humans and is classed as a hazardous product. The main advantage of caustic soda is its ready availability globally.
From an environmental viewpoint, the main advantage of magnesium hydroxide is that it is a natural substance and requires little processing compared to other alkalis used in closed loop and hybrid scrubbers. The result is a much lower carbon footprint: 1 kg milled magnesium hydroxide (Brucite) ~ 0.0085 kg CO2, 1 kg magnesium hydroxide synthetic ~ 0.68 kg CO2, 1 kg caustic soda (NaOH) 50% solution ~ 1.13 kg CO2.
In conclusion, Mr Don said, “In the paper and pulp industry, brucite has been selected for its lower carbon footprint, and we believe that also in shipping, the carbon footprint will increase in importance, especially with IMO 2030 in mind.”
Aiming for 2030
How the emissions abatement industry can help drive forward efforts to reach IMO 2030 targets was the theme of Daphne Technology head of sales and marketing Neil Anderson. His premise is that shipping does not have a holistic or fully formed idea of what decarbonisation means. He noted that the timeline of the next regulations to tackle emissions are retrospective. He called for “regulatory agnostic technology” and a rethink to future-proof assets against changing regulations.
This is the mission of Daphne Technology, he said, to produce emissions abatement technology that removes SOX, NOX and particulate matter and does this without any moving parts. The system will be designed to be installed without drydocking and without opening the sea chests. The system will produce fertiliser as a by-product.
How will this system work? The exhaust gas enters the unit with an injection of urea. At the centre of the system is a heat exchanger and humidifier, controlled by electronics. The fertiliser is collected and the NOX, SOX and particulate matter recovered. “Daphne is looking forward to eliminating more pollutants as IMO develops its strategy.”
The emissions abatement industry’s frustration with IMO was expressed by Mr Latun, “It is not possible to pick one environmental factor and try to resolve that. IMO needs to take on a more holistic approach”.