Future Transportation Systems - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 282

In the future, SO x emissions can be decreased by:
• Global reduction of sulphur content of up to 1.0% by 2015. EU ports have
required low sulphur content fuel since January 1st, 2010;
• Global reduction of sulphur to 0.5% from 2020; and
• General use of sea water scrubbers.

A special problem of ship technology is the demand for storage of the caustic
soda produced on ships with the SCR technology through the use of sulfur-con-
taining fuels.
A further problem of fuel supply is the cost saving bunkering of future, i.e.,
alternative fuels, such as synthetic and biogenic fuels, which need additional
measures to be optimally bunkered. Alternative fuels and fossil fuels, such as
HFO, MDO, and MGO require separated tanks and sensors to monitor combustion
quality. Blended fuel requires homogenizers.

17.3.1.3 Reduction of Particles

Decreasing particle emissions is especially important in marine engines in com-
parison to other types of transportation. However, elemental carbon, such as soot, is
by far the smallest part of particles emitted by marine diesel engines. Approximately
80% of the particles are sulfur products, such as sulfates and sulfur contained ash
which are produced in the combustion process by sulfur in the fuel. The chemical
process of sulfur reaction cannot be effectively influenced by the engine [ 54 ].
MGO fuel produces the smallest environmental problems burnt in ship engines.
Typically, particle emissions from ships using MGO fuel are 30% lower than those
using HFO fuel. The best levels of particle emissions can be reached in large, slow
speed marine diesel engines. The concentration level of emissions in this case is
comparable to high speed engines in automobiles.
The consumption of lubrication oil also contributes to the particle emissions.
The amount becomes higher at high loads and high speed of the engine. Large
marine engines usually do not need to change their lubrication oil [ 55 ].
IMO requires the reduction of particles in engines operating with HFO. Reg-
ulation of the sulfur content of fuel is only the first stage. Further important
measures for lowering particle emissions are:

• Improving the injection and nozzle system, e.g., introduction of slide valves;
• Optimizing the mixing technology in the combustion chamber;
• Using intelligent catalysts, particle filters, and scrubbers; and
• Developing an entirely electronically controlled engine system.

17.3.1.4 Integrated Catalyst and Filter System

Currently, single filter system is state of the art in ship technology. In the long
term, particle filters will be integrated into catalyst system in an effort to