SCR Systems for Marine Drive and Auxilliary Engines
Growing concern over the environmental impact of shipping has forced local, regional and global action, requiring reductions in emissions of NOx, SOx, VOCs, PM and other toxics. Johnson Matthey’s SCR system and other catalytic technology helps the largest ocean-going vessels and smaller ships comply with existing and anticipated regulations.
Globally, the International Maritime Organization (IMO) has set a progressive timetable for limiting NOx and SOx emissions. In Emission Control Areas (ECA) tighter limits and an accelerated timetable of restrictions apply to ocean up to 200 nautical miles from the coastal baselines. The number and coverage of ECAs, including those in effect for the American and Canadian coastlines, is growing.
In October 2008, the IMO adopted stringent new standards to control harmful exhaust emissions from the engines that power ships. The member states of IMO agreed to amend Annex VI to the International Convention on the Prevention of Pollution from Ships (MARPOL), adopting new Tier 3 standards to control NOx and fuel sulfur. The most stringent of these new emission standards apply to ships operating in the ECAs.
- Beginning in 2015, fuel used by all vessels operating in these areas cannot exceed 0.1 percent fuel sulfur (1000 ppm). This requirement is expected to reduce PM and SOx emissions by more than 85 percent.
- Beginning in 2016, new engines on vessels operating in these areas must use emission controls that achieve an 80 percent reduction in NOx emissions.
In most cases, ships already have the capability to store two or more fuels. However, to meet the 2015 requirement of 1,000 ppm fuel sulfur, some vessels may need to be modified for additional distillate fuel storage capacity. As an alternative to using lower sulfur fuel, ship operators may choose to equip their vessels with exhaust gas cleaning devices or scrubbers, which extract sulfur from the exhaust.
IMO regulations will have a significant impact on ship engine activity (for propulsion, auxiliary power generation, etc) in ECAs with the NOx limit restrictions (for ships launched starting in 2016) expected to require the use of after-treatment technology.
The most effective means of removing NOx is the SCR system. Nations such as Norway are using market instruments such as the NOx Fond to force a reduction in such emissions. SCR is proving to be a popular choice as the best available technology.
Johnson Matthey's SCR Systems, with urea injection, have been successfully applied to shipping to remove up to 95% of NOx. Our first SCR system was installed in 1995.
Today, more than 50 ships burning MDO, HFO, ULSA or LNG fuels are equipped with Johnson Matthey technology. That includes 163 SCR systems on marine diesel drive and APU engines and 25 SCR system on marine boilers.
Johnson Matthey manufactures the key component of the system--the catalyst—and engineers it, offering vessel owners long-term support from conceptual design through engineering through after-sales service.
In offshore processes such as LNG re-gasification, local regulations can require restrictive limits on emissions of VOCs, CO and NOx. Johnson Matthey's family of products, for example SCR in conjunction with an oxidation catalyst, have been used to meet these requirements with excellent results.
Island power systems—gensets--are also part of Johnson Matthey’s marine emissions control application expertise. Johnson Matthey has extensive experience with these packaged combinations of stationary diesel engines, generators and various ancillary devices, including base, canopy, sound attenuation, control systems, circuit breakers, jacket water heaters and starting system.
Johnson Matthey has designed, engineered, synchronized and serviced numerous of these prime power installations across the globe, which usually include at least three, and as many as 20, diesel generators.
In the U.S., EPA is addressing emissions from marine engines in two ways--through their fuels and through their emission limits.
In May 2004, as part of the Clean Air Act Nonroad Diesel Rule, EPA finalized new requirements for nonroad diesel fuel that decrease the allowable levels of sulfur in fuel used in marine vessels by 99 percent. These fuel improvements became effective in 2007.
In March 2008, EPA finalized its three-part program to dramatically reduce emissions from marine diesel engines below 30 liters per cylinder displacement.
These include marine propulsion engines used on vessels from recreational and small fishing boats to towboats, tugboats and Great Lake freighters, and marine auxiliary engines ranging from small generator sets to large generator sets on ocean-going vessels.
EPA also has proposed NOx control regulations affecting marine applications in Tier Stages 2 and 3 that will continue to become effective through 2020.
In offshore processes such as LNG re-gasification, local regulations can require restrictive limits on emissions of VOCs, CO and NOx. Johnson Matthey's technology, for example, SCR in conjunction with an oxidation catalyst, has been used to meet these requirements with excellent results.