Slow uptake hinders NOx technology progress

08 Aug 2017
WinGD's high-pressure SCR unit with a 6X72 engine on shop test with Hyundai Heavy Industries

WinGD's high-pressure SCR unit with a 6X72 engine on shop test with Hyundai Heavy Industries

Equipment manufacturers have yet to reap the rewards of investment in Tier III NOx abatement technologies, according to updates from the two leading low-speed engine designers.

Since the first NOX emission control areas were established in January 2016, MAN Diesel & Turbo and Winterthur Gas & Diesel (WinGD) have logged just over 150 orders for engines employing selective catalytic reduction (SCR) or exhaust gas recirculation (EGR) to meet Tier III NOx limits - an orderbook that does not come close to paying back the millions in research and development dollars still being spent on adapting NOx technologies for two-stroke engines.

As of 20 June, two-stroke market leader MAN Diesel & Turbo has 61 engines with selective catalytic reduction (SCR) on order, of which nine are already in service. Of these, 35 engines will be used with high-pressure SCR, with the unit installed upstream of the turbocharger. A further 48 engines, four of which are already in service, employ exhaust gas recirculation (EGR) to meet Tier III NOx limits.

Winterthur Gas & Diesel reports that some 45 engines are on order with SCR, 25 of which will be high-pressure units. Five engines with high-pressure SCR are already in service, the company said. The first engine with a low-pressure unit will be shop tested later this year and the company is investigating and applying test applications for EGR on its dual-fuel and diesel engines

Tier III NOx limits currently only apply to vessels plying the North American and Caribbean ECAs, where vessels with keels laid before 1 January 2016 must meet lower NOX emission levels. The current slow newbuilding market, and a pre-emptive rush by owners to lay keels before the new requirements entered into force, mean that so far there is low demand for Tier III compliant vessels.

The small number of orders has meant low returns for suppliers investing in the technology, and also appears to have impeded the development of products from other suppliers. To date, only three out of seven SCR suppliers for MAN engines – Hitachi Zosen and Hyundai Heavy Industries for high pressure, Doosan Engine for low pressure – have units in service. Of those, only Hitachi’s system is fully approved.

As reported, MAN Diesel & Turbo’s own high-pressure SCR system has only recently passed its engine shop test. The other suppliers are Hudong Heavy Machinery and Sunrui Engineering for high-pressure SCR systems, and Hyundai Heavy Industries and SMDERI for low-pressure units.

Meanwhile MAN has reported it is working on third generation advances of its EGR technology, including reducing the cost of its high-sulphur fuel version and exploring combined EGR and scrubber water treatment.

Engine developers’ orders may not provide a comprehensive view of the Tier III market, according to class society DNV GL. In its recent NOx Tier III Update the company noted numerous reports of companies ordering Tier II compliant engines, and then authorising an independent SCR maker to apply for Tier III approval for the combined system.

“In these cases the SCR maker is obliged to get a written agreement from the engine manufacturer that engine-specific data can be used for the Tier III certification of the combined system or for establishment of a Tier III engine group,” the class society noted. “In cases where this written agreement is missing (or the engine manufacturer has refused to issue its agreement), certification of the combined system is a challenge, because it can be difficult to obtain the required data.”

Meanwhile suppliers including engine developers are working on other NOx abatement technologies that could eventually eliminate the need for SCR and EGR units. These technologies - including water injection, emulsion fuels and intake air humidification - focus on lowering combustion temperature to reduce NOx production, but cannot yet reach Tier III reduction levels. Faster uptake of Tier III technologies could spur development of these less costly and space consuming solutions.

The uptake of Tier III technology is expected to increase from 2021, when the Baltic Sea and North Sea NOx ECAs will come into effect.

Orderbook: MAN B&W engines, Tier III NOx with SCR, delivery in 2018