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Sulphur cap forces choices on emission monitoring systems

Mon 06 Mar 2017

Sulphur cap forces choices on emission monitoring systems
Am EMS filter probe installed on the weather deck just above a scrubber outlet (Credit: Emsys Maritime)

Choosing the right emissions monitoring system (EMS) is essential to be certain that a ship meets the global cap on sulphur emissions, believes Simon Brown, managing director of the emission monitoring specialist, Emsys Maritime. Mr Brown was chairman of IMO’s working group of experts that revised its NOx Technical Code as part of the MARPOL Annex VI revisions in 2007-9.

In an article on the company’s website, he has outlined essential factors when choosing an EMS for an exhaust gas scrubber, which starts with its specification. “Get your requirements correct at the start,” he said, which includes confirming what equipment it is monitoring – an engine or a boiler, for example – and what local regulations the EMS should be type-approved for.

Before the EMS is installed, it should be tested, and Mr Brown recommended attending its factory acceptance test to see the system assembled and speaking to its designers. This might “bring up some items that may not have been considered at the requirements stage,” he said. He also recommended preparing a detailed onboard test plan to check the system performs to specification.

When installing the EMS, it is important to consider where the sample points and control panels will be sited. “Ensure that the probes do not become contaminated by scrubber washwater, sootblowing or turbocharger cleaning materials,” Mr Brown advised. Its control panel and analysis equipment must also be thoughtfully located so that its operators have easy access to each part of the system for maintenance.

“Shipbuilders have different selection criteria to the shipowner,” Mr Brown observed, when he turned his attention to operating costs. Yards, he said, usually focus on capital cost and ease of installation, which “may mean you end up with a system that is more expensive to operate,” he said.

Then there is maintenance. It should be well documented and relatively straightforward, he said, so “complex analytical systems that need regular servicing by specialist technicians should not be considered.”

His final advice is about training, but it is “probably the most important consideration of all,” he said. Because a ship’s crew is regularly changed, “a single training session at commissioning is not usually sufficient.” Although training is expensive and time-consuming, he said, “you cannot afford to ignore this most important aspect.”

In summary, he warns of the risk of falling for “the inkjet printer strategy of low upfront cost but back-end loaded profit in the cartridges.” In his view, “a well specified system will be reliable and cost-effective [while] a poorly specified EMS can become a significant burden to the ship’s crew and end up costing more than the system’s capital outlay if you have to switch to MGO whilst waiting for parts or service.”