Alfa Laval PureCool – making LNG great again

To stay on topic with the previous post about emissions and what is the IMO plan to reduce greenhouse gas emission, this week, Alfa Laval launched a new maritime environmental system, Alfa Laval PureCool. The system comes to help ships in reducing the methane slips from their gas engines. Why is this important? Because methane is one of the culprits in climate change and global warming.

The PureCool was first announced to the press in June 25, 2020. In combination with WinGD’s iCER Technology, it targets an unaddressed emission source, methane slip.

A methane slip is a small percentage of unburned methane that escapes through the engine when LNG is used as fuel. Methane is the main component of LNG and as it turns out, a potent greenhouse gas, with a global warming potential higher than of carbon dioxide. This however, should not detract from the fact that LNG can play (indeed already is playing) a significant role in shipping’s decarbonisation.

Currently there is no regulation to address methane slip from LNG however this might change as more and more ships transition to LNG over traditional fuel oils.

When it comes to how methane is measured, there have been two reports in the last years that show how similar facts can give rise to different interpretations of the impact of methane emissions.  In April 2019, the consultancy thinkstep analysed the GHG (greenhouse gases) emissions impact of LNG as a marine fuel across its lifecycle. In January this year, the International Council for Clean Transport (ICCT) released a similar report. While the authors of the thinkstep study argued that ship engines using LNG emit less GHG than those burning heavy fuel oil, the authors of the ICCT report used broadly similar numbers to argue that gas engines are worse emitters than those burning conventional diesel.

As per Wartislla, it is believed that the ICCT report does not reflect the latest gas engine technology.

Regardless of the report, it is clear that in order to retain the climate benefits of LNG, methane emissions must be addressed. Alfa Laval’s PureCool seems to come to the rescue in the matter.

PureCool and iCER – how do they work?

Developed by Alfa Laval in close collaboration with WinGD, PureCool is the cascade exhaust gas cooling system at the heart of the iCER (Intelligent Control by Exhaust gas Recycling) concept. The iCER option is a standalone installation adjacent to the engine. During operation in gas mode, it improves combustion by cooling and recirculating about 50% of the exhaust gas through a low-pressure path with full turbocharger capacity. This minimizes methane slip and the PureCool system provides the vital cooling function to make it possible.

Trials have shown a reduction of methane slip up to 50%. Additionally, when combustion is improved with iCER, fuel consumption in gas mode is reduced by 3% leading to fuel and energy savings.

The International Maritime Organization (IMO) has the target of cutting vessel-related greenhouse gas emissions by at least 50 percent by 2050. As the marine industry works towards a future based on non-fossil fuels, LNG is expected to be one of the transition fuels towards decarbonization. With or without new regulations, reducing the methane slip with the iCER option with PureCool seems to have a positive impact with long term results. We will just have to wait and see how the maritime industry embraces the new technology and if IMO will decide to support this by regulating methane as well.

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