Future Transportation Systems - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 280

100

80

60

40

20

0

emulsion
with 20% H 2

emulsion and
late injection

exhaust gas
recirculation 10%

water injection
with 50% H O 2

SRC

Fig. 17.12 Decreasing diesel nitrogen oxide emissions from ships

17.3.1 Near Future Phases of Development

New developments in all types of ships, such as bulk carriers, tankers, container
ships, cruise ships or freighters, etc., will increase their safety, economy, power,
durability, and flexibility. Besides the development with fossil fuels in the con-
ventional way, continuous development will be possible if new types of fuels and
renewable energy sources such as wind and sun energy will be used with higher
efficiency. Complementary new propulsion technology will become more

important.
Decreasing exhaust gas emissions with internal and external measures will be
more important in the future. The inherent advantage of the slow speed marine
diesel engine is its high efficiency. The amount of HC and CO in the engine's
output is usually very small. However, the concentration of particles has to be
decreased with a special exhaust gas after treatment system behind the engine,
particularly when heavy fuel with high sulfur concentration is burnt. Marine
exhaust gas after treatment technology is important for decreasing SO x ,NO x , and
particle emission concentrations.

17.3.1.1 Reduction of NO x Emissions

There are increasingly strict requirements for decreasing emissions from the
engine and the exhaust gas after treatment device in marine technology. NO x
emission values must be lowered to MARPOL 73/78 Convention, Annex VI limits
between 2.0 and 3.5 g kWh -1 , i.e., 21.0 9 10 -6 and 36.8 9 10 -6 oz BTU -1 for
ships launched after January 1st, 2011 [ 45 ]. A further stage is the 80% reduction of
emissions with Tier 3 limits applicable from 2015/2016 [ 46 ].
NO x can be reduced by approximately 30-40% by injecting a direct water
emulsion and through further measures, e.g., late injection; see Fig. 17.12 .