Choosing the right ballast treatment system

31 May 2012
Nynas-operated bitumen tanker ‘Alcedo’ was retrofitted with the PureBallast EX system

Nynas-operated bitumen tanker ‘Alcedo’ was retrofitted with the PureBallast EX system

Swedish product tanker operator Nynas has chosen Alfa Laval’s PureBallast system for two newbuildings and two retrofits which are scheduled for commissioning this year; Alfa Laval outlines the rationale behind the choice of system.

Although the IMO Ballast Water Convention is still to be finally ratified, both Alfa Laval and Nynas believe that this will happen sooner rather than later, and both companies stress the wisdom of standing prepared in advance of the expected rush to get systems fitted in the immediate post-ratification period. Alfa Laval points out that it will take just one more major shipowning nation representing 8.5% or more of the world commercial fleet gross tonnage to finally make enforcement of international law a reality.

“I think the Convention will be ratified quite soon, which means that the international regulations will most likely take effect within the next two years,” says Nynas project manager for newbuilding Björn Karlsson, echoing industry thinking. “We at Nynas began preparing for ratification about five years ago when we started investigating options for ballast water treatment onboard the bitumen tankers we charter.”

Preparedness is the main reason why Nynas decided in 2008 to purchase and install Alfa Laval PureBallast ballast water treatment systems onboard two newbuild tankers. However, the company believes that its decision to invest in the system will end up saving money in the long run.

“Our vessels typically sail in waters too shallow for ballast water exchange,” explains Karlsson. “That’s why we decided to buy ballast water treatment systems onboard two newbuild tankers. The vessels we charter have a ballast water capacity of less than 5,000m³, so we didn’t have to comply immediately. But by doing so, we avoid the costs associated with retrofitting the vessels later.”

Selecting a ballast water treatment system that meets Nynas’ criteria for health, safety, security and the environment was also important. The company has a comprehensive policy in place and employs certified management systems to ensure minimal impact of its products and operations on the people’s health and the environment.

“We assessed the other IMO-approved ballast water treatment systems available at that time,” says Karlsson. “Nynas chose PureBallast because we believe that it was the best system available. Treating ballast water with a chemical-free system is better for the environment than the other systems. Plus PureBallast came with Alfa Laval engineering support, equipment quality, and spare parts and service availability in our trading area.”

As one of the first companies to install ballast water treatment systems onboard tankers, Nynas is blazing the trail for other tanker ship owners and operators. Being the first is never easy, but Karlsson notes it has been made much easier with the support and service of a reliable partner.

“Nynas has a solid long-term business relationship with Alfa Laval that spans more than three decades,” Karlsson confides. “We appreciate the engineering expertise and support that Alfa Laval brings to the table. The two PureBallast 500 systems we ordered in 2008 for the Ardea and Mergus, for instance, were not EX-approved because such systems did not exist at that time. But together with Alfa Laval, we developed a solution for our vessels.”

Alfa Laval adapted PureBallast to Nynas’ requirements for operation in a hazardous tanker environment with cargo at temperatures ranging from 160°C up to 250°C. Rather than installing the PureBallast system below deck as on vessels carrying cargo that is not potentially explosive, Nynas and Alfa Laval decided to build a pressurised structure on the ship’s deck. A double-door construction serves as an airlock and an over-pressurised ventilation system creates a gas-free zone to ensure safe operation. This enabled system certification by Bureau Veritas.

Alfa Laval support and service continued throughout installation. In fact, says Karlsson, Alfa Laval was instrumental in allaying shipyard concerns about installation.

“The Wuhan Nanhua Huanggang Jiangbei Shipyard, which built the Ardea and Mergus, is a relatively small yard with no prior experience in working with PureBallast,” recounts Karlsson. “Alfa Laval arranged a trip to the Mawei shipyard where PureBallast was being installed on another vessel so our shipyard workers could see firsthand just how compact and easy to install PureBallast is.”

“The old adage, ‘seeing is believing,’ held true in our case,” says Karlsson. “The interaction between the shipyard crews was priceless. It provided our Wuhan Nanhua workers with full transparency of the installation requirements for the PureBallast system. Alfa Laval went the extra mile for us, which really helped us a lot.”

Alfa Laval’s Shanghai office provided a natural link to PureBallast experts in Sweden in addition to quick access to local support in China. This gives Nynas, as well as other western shipowners, close contact with experts at the Alfa Laval head office in Tumba, Sweden, while the shipyard in China has the same direct contact with Alfa Laval Shanghai. In other words, both parties have close contact with their respective compatriots, which eases collaboration. According to Karlsson, Alfa Laval’s local and global presence and broad competence gives it a competitive advantage over other ballast water treatment manufacturers which only have local agents.

At the end of February 2012, Alfa Laval Shanghai commissioned the systems onboard the Ardea and Mergus.

Once Nynas decided on PureBallast for the newbuildings it charters, the company saw no reason to change course to retrofit older vessels. In July 2011, upon recommendations from Nynas, shipowner Frederiet placed an order for two PureBallast 500 EX, generation 2.0, the second generation of the PureBallast systems, for its Alcedo and Pandion bitumen tankers.

Rather take on the challenge of managing these projects, Nynas placed the job of retrofitting the vessels in the hands of Alfa Laval subcontractor Marine Environmental Solutions AB (Mesab) for design, class approval, project management, integration to onboard systems, installation and commissioning services.

“The advantages of having a turnkey partner are obvious,” says Karlsson. “It was only natural that we place our trust in Alfa Laval and MESAB, the people who know the system best.”

Karlsson appreciates having a turnkey ballast water treatment retrofit partner. Mesab dealt directly with the Falkvarv shipyard, where the ships docked for routine service. The entire retrofit process, from pre-survey and engineering survey to installation and commissioning services, took about three weeks from start to finish.

To determine the placement of equipment, Mesab conducted a pre-survey, which resulted in a detailed written report and 3D drawing of the system layout. In contrast, the engineering survey produceda set of drawings that enabled pre-manufacturing of all major piping in order to minimise vessel downtime. Installation, startup and commissioning services ensured proper function of the system.

When asked to comment on the cooperation with Mesab, Karlsson says, “Accountability speaks volumes.”

Back in 2008 when the PureBallast systems were ordered for the newbuildings, Nynas asked Alfa Laval to develop an Ex version. PureBallast 2.0 EX comes with additional safety modifications for Zone I, group IIC and temperature class T4, making it suitable for installation aboard most vessels that carry ignition-sensitive cargo. It also features a 40% power saving and operating benefits such as automatic flow control.

Thereduced power consumption of thePureBallast 2.0 makes it easier for shipyards to work with the designed power on board,” says Karlsson. “This is especially true for our bitumen tankers where available power is at a premium.”

The modular design of PureBallast 2.0 EX enabled the re-use of existing ship ballast water equipment and pipe work, which is another advantage for shipowners.

When asked about the best way to handle onboard systems, Karlsson has three words: reliability, compatibility and convenience.

“That is the way we like to work with our onboard systems. At Nynas, we strive to have as few suppliers as possible. It is better to have a larger scope of supply from one partner and then let them take complete responsibility for the reliable operation of the equipment or system,” comments Karlsson. “Reputation and reliability matter a great deal to us. We’re not just buying equipment, we’re investing in a partnership and the know-how, expertise, resources and support that comes with it.”

So it may come as no surprise that other Alfa Laval equipment, such as purifiers, fuel oil booster unit and fresh water generator, can be found onboard the vessels that Nynas charters.

For the time being, Karlsson does not anticipate the placement of new orders for PureBallast 2.0 EX system or other Alfa Laval equipment. He plans, however, to keep a watchful eye on the four systems currently in operation. The lessons learned from installing and operating these systems put Nynas that critical step ahead and ultimately makes the company better prepared for the future.

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