IMO PPR4 on EGR and SCR:
IMO consultation PPR4 (Pollution Prevention and Response): relevant outcome for the maritime technology sector:
Last week the 4th meeting of the Pollution Prevention and Response (PPR4) of the IMO was held in London.
Relevant outcome for especially engine exhaust gas issues is listed below:
Catalyst (SCR) systems
It has been decided that there will be an adjustment of the NOx Technical code. In this adjustment, the currently used A and B scheme for engine certification and SCR systems will be harmonized; under the current regulations scheme B may be used when it is technically impracticable to use scheme A.
An unintended consequence of the current application of the 2011 SCR guidelines is that a shipyard must still sometimes act as certificate owner of the engine and SCR systems. A solution will be engineered for this, although procedurally it takes around 2 years to implement such a solution.
Furthermore, a revision was prepared for the 2011 guidelines. In this revision several technical clarifications have been included on the application of the guideline. MEPC 71 (July 2017) will still have to approve this revision.
Exhaust Gas Reciculation (EGR) systems
EGR is a method of reducing the NOx emissions from engines, and with this technique the requirements from NOx tier III can be met. NOx Tier III already applies to the United States and as of 2021 also for the North Sea and Baltic Sea.
The condensate which is created with the use of an EGR is a wasteproduct and should be treated as such. During the meeting a concept was drawn up ‘guidelines for the discard or bleed-off water from exhaust gas recirculation systems’. The concept still needs to be approved by the MEPC.
The guideline, amongst other details, sets conditions for the discharging of this water / waste mixture.
Engine Operational Profile (engine mapping)
PPR4 adopted a definition of what is an engine operational profile (‘map’). It was decided the topic will be on the agenda for these meetings, for which the aim is to examine whether it should be authorized to use multiple maps on one engine and, if allowed, what rules should apply there. An adaptation of MARPOL Annex VI and the NOx technical code is likely to follow.
We’ll keep you posted on these topics when they are discussed during the MEPC 71 coming July.