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The case for scrubbers

Chris Leigh-Jones, managing director of Krystallon, puts the commercial and environmental case for scrubbers.

Image related to: The case for scrubbersChris Leigh-JonesChris Leigh-Jones

From July 2010, ships entering northern European waters will be required to produce emissions no higher than the equivalent of burning a 1.0% sulphur marine fuel. Continuing to burn high-sulphur bunker fuel, the high-value, highly polluting fuel of choice for many years, without any form of emissions reduction technology is no longer a viable option. The International Maritime Organization (IMO) decreed in October 2008 that shipoperators in these Emission Control Areas (ECAs) have two options: to use more costly cleaner fuel, or fit scrubber technology onboard the vessel with the capability to remove sufficient sulphur (as SOx) derived from IFO180 and IFO380 to meet the new emissions regulation.

The economic angle

For owners weighing up their fuelling options, meeting environmental challenges may not be viewed with quite the same gusto as it was in January 2008, given the current financial turmoil in world markets. Yet, within what may emerge in 2010 as a new economic world order, environmental imperatives can still be achieved whilst remaining lean.

With fuelling costs in 2008 reaching more than 50% of a shipping company’s total costs, seawater scrubbing can offer many operators, owners and charterers continuity, assurance and value, as well as saving millions of dollars to boot; factors banks used to espouse. For owners looking at fuelling their fleet for the next 20 years of operation in an ECA, the maths is simple. The decision is based on assessing the premium paid for either 1% sulphur intermediate fuel oil (IFO), from 2010 to 2015 and marine diesel oil (MDO) or marine gasoil (MGO) in a 0.1% ECA thereafter, and comparing that premium to the cost of fitting a scrubber.

For ferry companies, coastal tanker operators, cruise lines and other vessels operating regularly in ECAs, fitting a retrofit scrubber is already a financially viable option. For operators entering ECAs – with one eye on the instigation of the 0.1% ECA set for 2015 – adapting a scrubber to newbuild fleets is a very compelling financial proposition. What is in little doubt is that “scrubber economics” work.

Sample costs

The take-up of scrubbing is built around huge cost savings for many types and sizes of vessels plying their trade in a variety of geographical regions. Given an indicative scrubber cost for a 34 megawatt (MW) engine is currently at $3.4 million (See Table), an expected rise in the price of bunker fuel through 2009 and into 2010, and shipyards that are increasingly adapting to new technologies, market forces continue to favour scrubbing for vessel owners. For example, a simple case study, based on a cruise ship operating in ECA conditions for 100 days a year, burning 50 tonnes a day of IFO380 high-sulphur bunker fuel per day over 1.0%, then lowsulphur bunker fuel (2010-2015), and ultimately MDO (2015-2030) provides a viable illustration.

Based on average IFO380 high-sulphur bunker fuel prices in Rotterdam of $300, a new vessel launched in 2010 with a lifespan of 20 years would save $125,000 per annum for five years (operating in a 1.0% ECA) and $1.55 million per annum for 15 years (operating in a 0.1% ECA) – a total fuel-spend saving of $23.875 million. With the International Energy Agency (IEA) predicting rising distillate fuel costs as shipping increasingly competes with other sectors for the “clean barrel”, these saving estimates are likely to be conservative. The chart above further illustrates that the larger the vessel engine, the greater the fuel cost savings over a five and 10 year period.

Image related to: The case for scrubbersThe case for scrubbers

Image related to: The case for scrubbersThe case for scrubbers

The NOx issue

In October 2008, the IMO ratified a number of changes to regulations pertaining to nitrogen oxide (NOx) emissions from ships. Tier III standards for new engines, anticipated for ECAs by 2016 and the strictest ruling ever for NOx, are expected to require dedicated NOx emission control technologies such as various forms of water induction into the combustion process (with fuel, scavenging air, or in-cylinder), exhaust gas re-circulation, or selective catalytic reduction (SCR).

There are also various systems available from aftermarket manufacturers including fuel treatment systems that reduce NOx, and some engine manufacturers claim that the combination of engine modifications and fuel treatment combined will meet MARPOL standards.

SCR is best suited to steady state load operation; the system typically does not perform well under manoeuvring conditions or at low temperatures or on high-sulphur fuels. For conventional NOx reduction technology, the majority of sulphur oxides (80%) must be removed from the emission prior to entering the SCR or the catalyst becomes blocked. This is a technical challenge the industry must face.

Shipoperators need to closely consider that achieving simultaneous SOx and NOx reduction by changing to ultra low-sulphur distillates eliminates the sulphur problem but significantly drives up the cost of the fuel and increases CO2. As we have seen from Graph 1, the cost of switching to cleaner fuels for many operators is prohibitive. The industry has two technologies – SCR for removing NOx and scrubbing for removing SOx and particulates – that perform well in isolation. The key now is to ensure they can work together to provide a single exhaust cleaning solution to remove SOx, NOx and particulates.

Limiting ozone production

One aspect not yet considered by IMO is that legislators often limit NOx in order to reduce ground-level ozone formation. By itself, ozone is a proven health hazard as well as a primary constituent of photochemical smog.

NOx contributes to ozone formation when hydrocarbons in an emission chemically react with the NOx in the presence of sunlight during hot weather. However, ozone production is hydrocarbon limited, meaning that the quantity emitted from an exhaust may, in effect, cap the potential for ozone formation assuming there are no other sources of hydrocarbons in the immediate vicinity. Sea trials have shown that Krystallon’s scrubber reduces volatile organic compounds (VOC) and hydrocarbon emissions by up to 85%. Unlike, for example, road vehicles, ocean-going vessels spend the vast majority of their time where there are virtually no other sources of hydrocarbons or they can be removed in a scrubber, so ocean-going vessels with scrubbers produce very low potential to generate smog. As a result, the reduction of hydrocarbons is essentially equivalent to a comparable reduction of NOx.

Combining solutions

As well as those listed, there are other solutions to the issue of SOx and NOx reduction compatibility and Krystallon continues to work closely with SCR experts to ensure continuity in meeting MARPOL Annex VI and NOx Tier III standards simultaneously. Successful scrubbing can be achieved with seawater, as in the Krystallon model, or with the use of additional chemicals, or a combination of both. Wartsila favours a closed-cycle freshwater scrubbing system with caustic soda addition. Clean Marine have a choice of either seawater or seawater with caustic soda as a booster while Krystallon now have four scrubbers operating with seawater. Krystallon, like other marine scrubbing companies, agrees that when operating in areas such as the northern Baltic or US Great Lakes, chemicals will always be necessary in order to achieve acceptable water-discharge conditions.

All concepts have their individual merits. Krystallon’s seawater scrubber benefits from its sheer simplicity. Manufactured from high-nickel chrome alloy steels specifically developed for the application, it fits into the funnel space being both lightweight and selfsupporting. The scrubber is designed to run cool, operating on sea water, although, under emergency conditions, it can be operated at temperatures up to 450°C. A washwater treatment system handles the full scrubber water flow and is designed to remove both the solid particulate and liquid hydrocarbon waste products. A very efficient design reduces contamination to levels measured in parts per billion. All materials are manufactured from corrosion-proof GRE.

The environmental argument

With average SOx levels from ships currently 250 times more than the world’s car fleet and reportedly killing 60,000 people prematurely annually, the need for an overhaul of ship fuelling becomes clear. Clearer still when the impact of shipping’s particulate levels are added to the equation; a deadly pollutant – almost eliminated by scrubbing – that is also contained in distillates.

There are other concerns emerging about the damage caused by soot, or black carbon, from ships traversing northern sea lanes. When the Arctic snow melts, it exposes dark land below it, further accelerating regional warming. According to Dr Charlie Zender, a climate physicist at the University of California, changing the timing of such soot emissions could play a role. “If you have to burn dirty fuel, you can do it in the fall or winter” when it will be buried under subsequent snowfall, Zender says.

However, the annual increase in meltdown may be the impetus for an accelerating doom as it opens up shipping lanes previously blocked by ice in the Arctic Sea. “Those ships are great emitters of soot,” Zender points out, adding that, “putting a locally heavy source in the Arctic in the early spring,” is virtually guaranteed, “to polish off the summer sea ice”. It is worth noting that sea lanes, such as those in the Gulf of Alaska, record 40% more soot emissions than non-shipping regions. With these lanes not anticipated to see the introduction of 0.5% sulphur fuel until 2020, and more likely 2025, only scrubbers can ensure that shipping does not sound the death knell to the ice caps.

When 100% SOx and 85% particulate can be eradicated by simply fitting a new technology to vessels – and in so doing save vessel owners, shippers and consumers billions of dollars of unnecessary fuel costs – scrubbing for marine applications stands up to thorough analysis.

At a roundtable hosted at the Sustainable Shipping forum in October 2008, the acclaimed marine environment academic Prof. James Corbett from the University of Delaware, offered a vision of how the marine market will react to scrubbing. Corbett said: “Before the US added sulphur scrubbing on power plants there was a thought that the unit cost would be $2,000 per tonne of SOx, but once the regulation was passed the price came in at $200 to $400 per tonne when the market knew what was needed … For marine scrubbers it’s likely to be a ‘good news’ story once the signal is given.”

Added 30 August 2009 in the category: Environment

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