FLUECHEM’S AUS40 BUFFER SOLUTION ADDITIVE AVOIDS COSTLY REPLACMENT OF OFF SPEC AUS40 ON LARGE BULK CARRIER

US40 Shelf Life

Fluechem’s team of industry experts have more than 16 years of experience in the AUS40 and Selective Catalytic Reduction (SCR) Industry and a proven track record in delivering technical and operational solutions and support across a wide range of vessel types and locations.

ISO 18611:2014 Part 3 describes best practice recommendations and requirements for handling, transportation and storage of AUS 40 necessary to preserve the specified quality of AUS 40 in order to ensure the proper function of the selective catalytic reduction (SCR) systems on board ships.

In order to avoid any impairment of the AUS 40 quality during transportation and storage, the standard details a number of conditions that should be taken into account in order to prevent decomposition of the urea, as well as the evaporation of water in the case of vented containers.

The minimum shelf life of AUS40 on ships is 18 months subject to an ambient storage temperature of 0⁰C to 25⁰C with it reducing as the temperature increases above 25⁰C. Other key factors impacting shelf life are the initial alkalinity and the difference in evaporation between vented and non-vented storage containers.

Many new build vessels who have never entered a NOx Emission Control Area (ECA) now have AUS40 onboard older than 18 months which is untested and potentially out of ISO 18611 specification which could result in damage to the SCR system and non-compliance with emission standards.

The normal solution would be to pump off the out of specification AUS40, product disposal and re-stock with new AUS40 resulting in a substantial disposal and supply cost as well as an increased environmental impact.

Background

During 2025 Fluechem developed and executed a risk based assurance program with one of its key customers, who manages over 700 ships, to ensure all vessels fitted with SCR systems had compliant AUS40 onboard. The process identified a number of vessels where the AUS40 onboard could be out of specification.

Assurance Process

• Stage 1 – Portable AUS40 refractometers were dispatched from Fluechem’s stock direct to the vessels to test the tank contents and get a representative measure of the urea content of the AUS40 in storage at standard conditions.

• Stage 2 – Where deviations were noted, samples were collected for analysis by Fluechem’s global network of independently accredited laboratories.

• Stage 3 – The output from the laboratory analysis was used to develop an AUS40 buffer solution additive to bring the current volume of AUS40 onboard within the ISO 18611 standard and any specific characteristics of the SCR system fitted on the vessel.

• Stage 4 – In collaboration with the vessel team, an onboard operational program was developed to blend the AUS40 buffer solution additive with the AUS40 stock onboard, including the test protocols and delivery process.

The Solution

Having formulated the AUS40 buffer solution additive required, the Fluechem operations team liaised with the vessel directly for the delivery place and time as well as the local blending plant to ensure the additive was available during the nominated port call.

Once the additive was safely onboard our technical team provided 24/7 support to the vessel Chief Engineer to complete the onboard operational program.

The Result

The entire stock of AUS40 onboard was returned to ISO18611 standards ready for use whilst extending shelf life thereby avoiding having to pump off the out of specification tank stock, product disposal and stock replacement operations resulting in a substantial cost saving for the vessel owner and a reduced environmental impact.

“This operation exemplifies the benefits of having a strong technical understanding of the products we sell and a team with the ability to address associated operational issues effectively when they occur” said Niall Roberts, CEO of Fluechem. “Working closely with the vessel allowed us to develop an innovative solution that not only saved money and reduced the operational impact on the vessel crew, but more importantly, avoided the environmental impact of having to dispose of the off-spec AUS40 onboard and replace it with new AUS40 underpinning our Unique Selling Points of EXPERIENCE, CUSTOMER DRIVEN SOLUTIONS and INNOVATION.”