Wartsila Diesel striving for further NOx, carbon dioxide reductions

Wartsila NSD recently signed a deal with John Crane-Lips, part of the TI Group in the UK, to strengthen its commercial position.

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Diesel engine of the type being installed in the Saibos FDS deepwater construction vessel.
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Wartsila NSD recently signed a deal with John Crane-Lips, part of the TI Group in the UK, to strengthen its commercial position. The coop eration agreement between the two companies will enable customers to purchase complete marine propulsion systems from a single source.

This divests them of the responsibility for combining the basic elements of the system - engine, gearbox, propellers, thrusters, controls and so on. Under the agreement with TI, Wartsila will act as the prime contractor to the shipyards and assume the role of integrator. Both companies will continue to supply their products separately to customers not wishing to adopt this new procurement approach.

Mikael Makinen compared the move with the changes seen in the offshore industry over the past several years. "It is not enough simply to supply the individual elements of the system anymore. People are looking for companies that are willing to take responsibility for functionality and to provide lifetime service support," he said.

As ship design becomes more complex and performance demands increase, Makinen believes that marine systems integration skills will become paramount. "In a commercial sense, it can help in two ways," he pointed out. "It lowers the barriers for owners to go to less sophisticated yards; for example, in China. It also enhances the competitiveness of the relatively more costly European yards, since in future they will require fewer specialist engineers working on their side."

Cleaner engines

Diesel engines have come in for considerable criticism in the past for their environmental performance, and cleaner diesel technology has been a constant focus for manufacturers, not least, Wartsila. The pressures to reduce emissions are strongest in the passenger cruise shipping market. However, when questioned about this, Makinen stressed that improvements to the engines would ultimately benefit users "across the entire marine and offshore spectrum."

For some time, Wartsila has been investing in ways of reducing the emissions from its engines of oxides of nitrogen (NOx) and sulphur (SOx), as well as carbon dioxide and smoke. The company was instrumental in the development of direct water injection technology, aimed specifically at tackling NOx levels - the first engines to incorporate the technology were the Wartsila type 46. Emitted NOx levels in the region of 4-6 g/kWh compare favorably with gas turbine engines, running on the same light fuel oil.

In addition to direct water injection, attention will be directed towards common-rail fuel injection. It is anticipated that this will further decrease NOx, reduce smoke levels below visible limits, even at low loads, and increase engine efficiency, hence improving fuel consumption and cutting carbon dioxide levels.

The common-rail fuel injection system being developed by Wartsila comprises a series of inter-connected pressure accumulators, the fuel pressure being generated by pumps driven by the engine's camshaft. Each accumulator serves the fuel injectors in two cylinders. The whole process works under close electronic control. The company envisages ultimately being able to retrofit this kind of technology to existing Wartsila engines in place of the conventional jerk-pump fuel delivery systems.

Turning to sulfur dioxide emissions, Makinen explained that that these were not simply engine-related, but depended on the grade of fuel used. Specifically addressing the advocates of gas turbine engines, he pointed out that diesels produce less sulfur dioxide than gas turbines when running on the same high-quality fuel, which the latter were forced to use.

Offshore sector

Wartsila occupies a strong position in the offshore market for diesel engines. The company was recently awarded a contract by Petrobras to supply a dual-fuel power generation package for the Petrobras P-VIII semi-submersible pro duction platform, operating in 400 meters of water in the Marimba field in the Campos Basin. The platform, which was originally built in the mid-1970s in Norway as a flotel, is being upgraded to include water injection facilities.

Two Wartsila Vasa 8R32LNGD gas-diesel generator sets will be added to the platform and the four existing diesel generators will assume a stand-by role. Each of the new units is rated at 3,700 kVA. Wartsila will also provide engine control panels, generator protection relay panels, a fuel gas conditioning package and the necessary equipment to interface the genset controls with the overall control and monitoring system onboard the platform. The work, which will be carried out while the platform remains in production, is planned to start in June and the units should be in operation by the end of the year. The P-VIII's own crane will be used to transfer the engines onto the platform and so partial dismantling of the engines will be necessary to bring the equipment within the crane's lifting capacity.

Later this year, Wartsila will deliver nine of its 16V25 gensets to Stena Offshore to power its Stena Don semisubmersible drilling rig due to enter operation in 2001. Stena's choice of these 3.6 MW units was based on a wish to have the same type of engine as those already installed in its earlier drilling rigs.

Finally, the new deepwater, multi-purpose crane and pipelaying vessel - the Saibos FDS, being built by Samsung for the joint venture company set up by Saipem and Bouygues Offshore - will be powered by Wartsila diesels. This state-of-the-art, dynamically positioned, field development vessel, which was designed to withstand the sort of sea conditions commonly experienced in the South Atlantic, is nearing completion in Korea. Power for propulsion and equipment will be provided by four Wartsila 16V26 and two 8L26 diesel engines. There will also be an emergency genset onboard, based on a Wartsila CW8L170 engine.

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