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ELIMINATION OF MATERIAL RELATED PROBLEMS IN NOx REDUCTION ON LARGE BORE DIESEL ENGINES BY INJECTING A REDUCING AGENT INTO THE CYLINDER

Objective


The main results can be summarized as follows:

Materials were identified which allow the design of injection nozzles for urea solution under high temperatures and pressures.
State-of-the-art common-rail injectors for diesel fuel-injection are not suited for injection of water or reducing-agent-solution due to their high leakage rates and wear.
Standard diesel injection nozzles can successfully be operated with water if
a sufficient amount of a suitable lubricant is added to the water,
- injection pressure is not too high,
- the nozzle is not used as a control device as is the case with certain common rail injectors.
The wear characteristics can be improved by suitable materials.
The NOx-reduction rate achieved with RAI is not sufficient. RAI is thus not economic.
A theoretical model for RAI has been developed which is able to explain the failure of this method.
With the combination of DWI + EGR + FWE it is possible to reduce NOx by more than 80 % while keeping reasonable smoke limits.
A filter system has been developed which is able to clean exhaust gases of diesel engines operated on HFO with an efficiency of 98 % with respect to SOx and 80 % with respect to particulates.
This filtering efficiency is however not sufficient to make possible the long term EGR operation of an engine burning HFO.
Materials for piston rings and cylinder liner have been developed which are able to provide state-of-the-art or even better wear results in an engine running with DWI.
For reduction of NOx from large Diesel engines in ships power stations the selective catalytic reduction (SCR) is assigned technology. It has several severe disadvantages, economically and technically as well as ecologically. To overcome this a package of engine modifications including reducing agent injection and exhaust gas recirculation has been developed which, however, is not yet applicable because of very high wear of engine components. It is the aim of this project to remove this obstacle by the application of new materials.

The main objectives for this purpose are the following:

A) Getting further insight into the mechanisms underlying the exorbitant wear phenomena observed in connection with reducing agent injection so as to improve the basis on which the questions of materials can be defined.

B) Finding a compromise between the NOx reduction and the wear involved.

C) Adaptation of the engine and the reducing agent injection system, in terms of design and materials used, to the higher corrosive attack, relying on the know-how as per A).

D) Testing of filtering systems that are capable of cleaning ash-bearing exhaust gases and that could be for filtering the gases in the exhaust gas recycling system.

A reduction of additional costs for NOx reduction of 30% is expected.

Funding Scheme

CSC - Cost-sharing contracts
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Coordinator

MAN B & W Diesel GmbH
Address
Stadtbachstraße 1
86153 Augsburg
Germany

Participants (4)

Industriale Srl
Italy
Address
Via San Quirico 19
16163 Genova
SEMT PIELSTICK
France
Address
Quai De Seine
93202 Saint-denis
STE
Germany
Address
Eupener Straße 150
5000 Köln
TECHNISCHE UNIVERSITÄT HAMBURG-HARBURG
Germany
Address
Denickestraße 15
2100 Hamburg