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the RFCC of valuable HCO for backflush and increased

overtime due to the constant blockage of the system’s

cartridges. The new electrostatic separator utilises

FCC/RFCC feed as the backflush medium, allowing the

reactor to run at full production with the reduction of

HCO recycle.

„

The recycling of small fines showed a reduction in

catalyst uptake due to longer reaction time and

increased fluidisation within the reactor. As mentioned

earlier, catalyst savings might vary depending upon

residual units due to multiple factors, but still remain

significant. Individual cases involving deep resid cracking

benefits should be calculated based on a thorough

knowledge of the RFCC feed, operating conditions,

catalyst characteristics, etc. It is important to note that

smaller catalyst particles returned to the unit have an

inherently larger surface to volume ratio and could have

a considerably higher resid cracking activity than the

larger equilibrium catalyst held in the unit. This is an

advantage when separating with electrostatic separation

due to the ability to collect sub-micron particles, too

small for mechanical filtration, during the separation

stage.

Conclusion

The lack of new refinery construction, ongoing

environmental enforcement concerns, and mandated

product quality issues have increased capital addition and

operating costs while reducing flexibility. The challenge for

refineries is to process crude into quality oil products by

removing the impurities as efficiently as possible, while

considering the environment. Each refinery is limited by two

main factors in this area: the products that the refinery is

designed to create and the quality and characteristics of the

crude oil used to create these products. From a filtration

standpoint, slurry oil/FCC fractionator bottoms is one of

the most challenging applications for a refinery. The

electrostatic separator provides an economic and efficient

solution to removing the catalytic fines that would

otherwise devalue residual fuel oil (RFO) and feedstock

products. Every refinery with an FCC/RFCC unit has this

need to highly concentrate solids in the slurry oil into a small

volume for easy recycling, while maximising the recovery of

saleable clarified oil.

By decreasing the operating temperature and not having

to use increased pressures for back washing, the electrostatic

separation process reduces overall operational cost,

maintenance and downtime. These factors provide valuable

returns from the ‘bottom of the barrel.’

References

1. MALLER, A. and DHARIA, D., ‘Alternative Feedstocks, Shale gas Drives

new Opportunities’, Technip Stone & Webster Process Technology,

Houston, Texas, US, (February 2015).

2. MINYARD, W. F. and WOODSON, T. S., ‘Upgrade FCC Slurry Oil with

Chemical Settling Aids’,

World Refining

, (November/December 1999).

3. ELLIOTT, J. D., ‘Impact of Feed Properties and Operating Parameters on

Delayed Coker Petcoke Quality’, presented at the ERTC 2008 Coking

and Gasification Conference.

4. Platts Methodology and Specifications Guide, ‘Petroleum Product &

Gas Liquids: US Caribbean and Latin America’, (January 2012).

5. SILVERMAN, L. D., WINKLER, S., TIETHOF, J. A. and WITOSHKIN, A.,

‘Matrix effects in catalytic cracking’, presented at the 1986 NPRA

Annual Meeting, Los Angeles, California, US, (23 – 25 March 1986).

6.

www.hyd.com/IssueArticle/Optimize-value-from-FCC-bottoms.htm.

7. GUERCIO, V. J., ‘US Producing, exporting more slurry oil’,

Oil & Gas Journal

, (4 October 2010).

8. MOTAGHI, M., SHREE, K. and KRISHNAMURTHY, S., ‘Anode Grade Coke

from traditional Crudes’, PTQ, Q2, (2010).