Friday, September 21, 2018
Maritime Propulsion

Posted by June 29, 2018

The Modern Approach to NOx Reduction

Logo: ADNOX A/S,

ADNOX A/S, the R&D start-up in which Hans Jensen Lubricators A/S recently acquired the majority stake, has released details of their Advanced Diesel NOx reduction method, “ADNOX”.

 

The ADNOX System is a SCR system using diesel oil as reductant offering more than 80% NOx reduction. The oil injected is converted to heat, leaving 50% more heat for recovery.

The advantages are:

  • No need for storage tanks for the reductant.
  • No extra overall costs of reductant.
  • The waste heat can be recovered for production or electricity.
  • Significant reduction of weight and space saving, leaving more cargo space.

 

Due to the harmful effects of NOx, the emission of NOx at sea is controlled by IMO requirements besides being regulated by local NOx taxes. To comply with IMO regulations a reduction of NOx of more than 75% is required for internal combustion engines running on oil in Emission Control Areas. Selective Catalytic reduction (SCR) of NOx using urea as reductant is the standard system today for NOx reduction, especially on ships.

ADNOX A/S has developed a full IMO TIER III compliant SCR System, using only diesel oil as reductant. This means that no extra storage tanks are required, and no crystallization of the reductant is experienced. Further to this, diesel oil is non-corrosive, and the evaporation and mixing of the diesel oil with the exhaust only needs a short pipe length upstream the ADNOX Reactor.

The ADNOX SCR system uses approximately 7 % of the total oil consumption, an amount equivalent to 14 L/MWh. The oil injected is cracked on the multi functioning catalyst and takes part in the NOx reduction (NOx -> N2 and H2O) which produces heat, increasing the exhaust temperature at reactor outlet. The increased exhaust temperature means an exhaust-boiler, can be installed after the Reactor and high-quality steam can be produced and used for production of water or electricity. In the case of an exhaust-boiler present, an electricity amount in kW corresponding to 7% of the shaft power output can be produced. I.e. more than 80 % NOx reduction can be achieved, at no extra overall cost of reductant. Furthermore, the ADNOX SCR system weighs approximately 40% less than the standard SCR system of today.

On four-stroke diesel engines, the Reactor is installed after the TC-Turbine. On two-stroke diesel engines, the Reactor is installed between exhaust receiver and TC – Turbine inlet.


The ADNOX SCR system is patented and has achieved an “Approval in Principle” by DNV-GL, confirming no risk of explosion. The ADNOX SCR system is fit for both retrofit and newbuilding application.

The ADNOX SCR system is developed in Denmark and patent applied. The inventor, Ole Fanøe mentions that the development was done on requests from ship-operators for a NOx reduction system, offering the same NOx reduction degree as conventional systems, however with less operational problems.
 

conventional systemsDenmarkdiesel oil