IMO TIER III AND BEYOND master

IMO tier III and beyond

Some years ago, with the end of the Wärtsilä 46 product cycle in sight, Wärtsilä decided to upgrade the engine design. In 2007, two new 6-cylinder in-line Wärtsilä 46F engines were delivered to the first customer - Wagenborg Shipping - for installation in Rijnborg, an open top container carrier. More than 22,000 running hours have now been accumulated on each of this vessel’s engines.

Text: RISTO PAKARINEN Photo: -

Some years ago, with the end of the Wärtsilä 46 product cycle in sight, Wärtsilä decided to upgrade the engine design. In 2007, two new 6-cylinder in-line Wärtsilä 46F engines were delivered to the first customer - Wagenborg Shipping - for installation in Rijnborg, an open top container carrier. More than 22,000 running hours have now been accumulated on each of this vessel’s engines.

“Wärtsilä 46F engines have now completed a total of more than 360,000 hours, and it has become one of our best-selling designs,” says Mikael Troberg, Director R&D, Testing and Performance, Wärtsilä. A total of 57 Wärtsilä 46F engines for ships and 29 for power plants have been delivered.

25-YEAR OPERATIONAL LIFECYCLE

“Since we started up the first prototype, we’ve worked hard on improving the Wärtsilä 46F’s performance - both efficiency and levels of emissions - and of course on validating everything,” says Troberg. “That takes time. Then we had to sell the new design, which can take up to a year, and the 12 months following that is spent on getting everything ready for delivery. After all, customers will be running their engines for 25 years or more, and they have to work as expected.”

According to Troberg, the previous Wärtsilä 46 design had reached the end of the road. Even though it was reliable, no further potential for development remained, so radical changes were required. Also, the new Tier II regulations from the International Maritime Organization (IMO) had to be met. “While the  46F is based on the previous version of 46, the engine speed was increased from 500 rpm to 600 rpm to maintain Wärtsilä’s competitiveness in this engine category,” says Troberg.

“This was quite a fundamental change, but the result was better performance and a more compact and cost-efficient design, offering higher output and improved levels of engine efficiency while meeting Tier II requirements.”

NO VISIBLE SMOKE

The changes from the previous version of 46 were substantial, the Wärtsilä 46F engine design is a new platform. “There’s still plenty of potential in terms of improving efficiency and smoke values,” says Troberg. “So there’s no reason to move to a new platform as the Wärtsilä 46F is still in the early phase of its product cycle – even if it is 10 years old.”

As is often the case, the new emissions limits initially appeared challenging. “Complying with the Tier II regulations looked to be almost impossible, but we successfully developed the required technology and now we know how to get to Tier III.”

On the Wärtsilä 46F, NOx emissions have been reduced by 20% and smoke emissions have been reduced to levels no longer visible to the naked eye. Smoke is important in the cruise business because cruise ships often sail into city harbours. “Limits are not actually placed on smoke emissions, so it’s what each customer prefers,” he says. “But the FSN (Filter Smoke Number) value of 0.3 we offer is so good that no smoke will be seen.”

DIRECT BENEFITS FOR CUSTOMERS

Development work on the new generation engine has also improved levels of fuel efficiency. “Simply adding items to comply with environmental regulations would push fuel consumption up,” says Troberg. “But we’ve been able to reach  fuel  savings of 3-4%. The challenge with tougher environmental regulations and reduced emissions levels is always to avoid increased fuel consumption. But we’ve actually managed to achieve better fuel performance.”

IMO TIER III AND BEYOND 1

While emissions levels must be complied with, improved levels of efficiency and reduced fuel consumption benefit customers directly. “Cruise ships, for example, are getting bigger and bigger, and their energy requirements are also increasing,” he says.

“Every gram of fuel consumed is important. A 1% improvement in fuel efficiency can result in annual savings of up to EUR 300,000. That’s a sizeable chunk of money, especially if a company is operating dozens of cruise ships.”

IN-HOUSE SOLUTION FOR NOX REDUCTION

The Wärtsilä orderbook is clear evidence that customers want Wärtsilä 46F engines. But when you are a technology leader, your focus is always on the horizon. By 2016, engines will have to comply with the IMO’s new Tier III standards and this initially felt like another impossible challenge. Engine manufacturers will also have to provide technology that allows switching between Tier II and Tier III operating modes while the engines are in operation.

With only a few years to go, the required levels of performance appear to be achievable, even though the difference between Tier II and Tier III emissions levels is considerable. Wärtsilä already has the necessary in-house technology.

Selective Catalytic Reduction (SCR) is a method of converting nitrogen oxides (NOX) into harmless nitrogen (N2) and water vapour (H2O) with the aid of a catalyst. Tested and proved, the technology has existed in different forms since the 1960s - it is still the most efficient method of reducing the levels of NOX emissions in engine exhaust gases.

ADDITIONAL SPACE REQUIRED

In SCR equipment, a reducing agent such as an aqueous solution of urea is injected into the high-temperature engine exhaust gases. The urea decays into ammonia, and the NOX reduction reaction takes place as the gases pass through the catalyst chamber.

According to Troberg, SCR technology actually represents an additional operational cost for customers in two ways. “While the aqueous urea solution required to operate the system is a direct cost, the SCR equipment takes up space that could otherwise be used to transport cargo. And there’s also the initial investment cost.”

“To be competitive, engines need to comply with Tier III emissions using technologies that allow for the retrofitting of existing installations. Adding SCR equipment to a ship that’s already in operation will be far from easy.”

TIER III COMPLIANCE WILL BE BUILT-IN

Wärtsilä is therefore working on developing next generation technologies for reducing NOX in laboratories. Another option is to change the fuel to LNG and thus achieve  Tier III levels , and this alternative is also available with the Wärtsilä 46F.

Time is however short. 2016 will soon be here, and customers now placing orders for vessels have to know what kind of engine technology they will be using. Initially, Wärtsilä will be offering SCR solutions while validation of all aspects of the new technology is completed, ensuring that a total package is delivered to customers.

Complying with regulations that require reduced emissions levels usually results in lower levels of efficiency - the exception is when completely-new solutions are developed. “We know how to do it,” says Troberg. “We just have to finalise the engine designs.”

 

Wärtsilä 46F

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