Stena Line

Innovation needed to eliminate SOx and NOx emissions from ship engine exhausts while burning high sulfur fuels so Sulfur Emission Control Area requirements are met.

What's the innovation challenge?

The ideal solution to this challenge would be one that would half the total cost of capital and installation compared to that of traditional closed-loop, in-line wet scrubber systems. And one that could easily be retrofitted onto cargo ships, passenger and freight ferries currently operating in the Sulfur Emission Control Areas (SECA).

Current practice

Historically, Stena Line ships run on a wide range of fuel types, with sulfur concentrations up to 3.5%, and under a wide range of engine operating conditions.

Recent changes to SECA fuel sulfur limits (from 3.5% to 0.1%) mean Stena have to either purchase costly low-sulfur fuel, or install SOx scrubbers to eliminate the equivalent amount of sulfur from ship engine exhausts.

Stena has had good success recently using closed-loop, in-line wet scrubber systems. However, the cost of these systems prevent rapid, broad adoption across fleet operating in Sulfur Emission Control Areas.

Key barriers encountered in reducing the cost of installing scrubbers include:

  • Current open loop systems which include many components, tanks, pumps, and associated piping spread across several compartments. This results system complexity and higher installation costs.
  • The corrosive environment within the scrubber which requires expense materials of construction.
  • The fact that scrubbers require large volume to provide sufficient contact time between the exhaust gas and wash water droplets.
  • Current systems that require large volumes of sea water, requiring large pumps and piping.
  • Closed loop systems which need a cooling step using large volumes of sea water. Open loop systems require large volumes of sea water to capture SOx from the exhaust gas.

Routes to Consider

Stena is keen to hear about novel designs for wet scrubber systems that are cheaper, have more compact, are less complex, and are easier to install on existing vessels. Any solution would need to be consistent with the practical space limitations of existing vessels, and not need the input of specialized skills or extensive training of operating personnel.

Areas to think about include:

  • Alternate locations for exhaust scrubbing outside the exhaust funnel (e.g., engine room).
  • Closed loop scrubbers that don’t require a wash water cooling step.
  • Open loop scrubbers with wash water cleaning to meet anticipated future environmental limits (e.g., pH, turbidity, PAH).
  • Plug-and-play or single compartment designs.
  • Emerging technologies for SOx and NOx reduction based on alternative modes of operation including dry absorption systems with manageable pressure drop and dry chemistry logistics and cold plasma. 

Evaluation Criteria

  • Technical Viability - Solutions proposed must be based on sound scientific principles and have laboratory or pilot scale data that demonstrate efficacy.
  • Scale up Potential - Solutions proposed must have a clear pathway to be application on commercial ships within 1-2 years. Solutions already practiced in marine markets have higher value. The ideal partner would be able to lead the design and installation of full-scale systems.
  • Costs - solutions would need to provide reasonable return on investment, consistent with the anticipated annual savings of using high sulfur fuels in place of more costly low sulfur fuels.
  • Ownership - Solutions covered by patents have higher value. At a minimum, proposed solutions must not be prohibited by other patents in the field.

Stena are inviting concise, non-confidential proposals that will describe the technical approach. Information included should focus on the technological readiness of the proposal, proof of concept data, reference to any peer reviewed publications, and potential route to commercialization.

Closing date for proposals 31 January 2019.

How to apply

Send your questions and proposals to Alan Gordon at Stena Line