Slurry Oil (MCB) Filtration

“Upgrading main column bottom product to a valuable commodity can add revenues up to $40/barrel !"

By removing catalyst fines from slurry oil, or main column bottoms, product fuel oils can be upgraded, or feedstock can be provided for production of carbon black or other products.

Royal Dahlman designs fully dressed (R)FCC Slurry Oil Filtration packages, based on field-proven filtration technology offering the following main features & benefits:

  • Highly effective in-situ gas driven element cleaning, minimizing backwash volumes and utility costs
  • Continuous solids reduction to < 50 ppm wt
  • Full process performance guarantee
  • Non-stop operation from TAR to TAR
  • Advanced PLC or DCS control system
  • Compact, skid-mounted design and delivery reducing OPEX and site installation costs


Royal Dahlman has the technology for the Oil Refiner to comply with the new IMO 2020 Marine Residual Fuels.

IMO 2020 will be effected now soon and the industry is making up for it. SOx and particulate emission (PM) controls apply to all fuel oil, as defined in regulation 2.9, combustion equipment and devices onboard and therefore include both main and all auxiliary engines together with items such as boilers and inert gas generators.

For keeping compliance some shipowners have invested lately in heavily in closed-loop or open-loop scrubber technology of which the latter technology is already banded by major (bunkering) ports such as China. China’s move on banning open-loop scrubbers follows similar regulations by Singapore, Belgium, California, Massachusetts and along Germany’s Rhine river. Other countries are also assessing whether or not to allow the technology ahead of the IMO 2020 regulations starting in a few months now. Hence, shippers will be limited having a choice to use closed loop scrubbers or bunker low Sulphur fuel oil (LSFO).

LSFO though also needs to be compliant with the ISO 8217 2017 standard if bunkered. It is not only the limitation of SOx for all marine fuel oil set by IMO regulation 14 but also for the PM emissions. Inside the Emission Control Area (ECA) the limit of SOx and PM emissions is set at 0.10% m/m (already effective since first of January 2015) and 0.50% m/m on and after first of January 2020 outside of an ECA. As of now the North America Area and the United states Caribbean Sea are legislated on SOx ánd PM while other ECA's are limited on SOx emission only.

Today the industry is heavily discussing on the Sulphur content in the bunker fuel oil while little attention is given to the cat fines content that not only cause high PM emission from combustion engines but also cause wear and tear to cylinders and pistons in the ship engine. Cat fines, small catalytic particles used in the refinery to crack residues into lighter fractions entrain from the process as they are not being separated from the hydrocarbon product streams by the cyclones simply because these can't operate efficiently at smaller particle sizes. Catalytic fines consist predominantly of Aluminum (Al) and Silicon (Si). The ISO 8217 2017 fuels standard for marine residual fuels gives for Aluminum + Silicon maximum 60 (mg/kg).

Some refiners operating an (R)FCC sell their residue from the Fluid Catalytic Cracking Unit as bunker fuel blended into a fuel pool. This is especially attractive when used for blending down Sulphur content of bunker fuels. Problem however is that cat fines concentration in the FCC Slurry Oil stream may be as high as 1000-3000 (mg/kg). Being aware of the limitations of the majority of the onboard fuel treatment systems, most ship engine manufacturers specify a maximum concentration of 15 (mg/kg) at the main engine inlet.

Royal Dahlman has developed and proven the filter technology for filtering the FCC Bottoms down to or less than the required cat fines levels. We offer the refiner the possibility to simply sending us a sample of (R)FCC Slurry oil for performance testing in our laboratories.


Slurry Oil testing related to IMO2020

For refiners, blending their slurry oil with low sulphur bunker fuels can generate significant higher revenues compared to current slurry oil destinations. Filtration of slurry oil however is required, to bring down PM below 50ppm.

Royal Dahlman has developed an elaborate slurry oil analysis and filtration test program, that provides valuable insight for the design of reliable and robust filtration systems.

Sample analysis of slurry oil seems simple when following the common available test protocols (like; ISO 10307-1) but, there is much more information to gain than the outcome of these standard tests.

With the Turn Around (TAR) interval shifting to 6 years or even longer, it is necessary to eliminate any surprise that could negatively impact the operational reliability of the (R)FCCU. Next to sample analysis, extensive testing is performed on lab scale slurry oil filters to define the filtration characteristics and determine the optimal operating parameters.

This unique analysis and testing protocol has drawn the attention of (R)FCC licensors and operators. This approach enables Royal Dahlman to provide firm guarantees on performance, filter element lifetime and operating parameters, thus ensuring client operations.