Rethinking Old Problems
New design improves FCC slurry pumparound
Rising global demand for transportation fuels and propylene as a chemical feedstock will require new and revamped FCC units to increase supply. Technology enhancements have historically focused on improved or new catalyst formulations, updated feed nozzles, and reactor/regenerator designs. FCC charge rate and reactor temperature are often limited by performance of the main column and bottoms system. To fully capture benefits associated with tailored catalyst formulation or new reactor/ regenerator designs, the main column and slurry pumparound system must be up to the task. For many refiners, problems in the main column and bottoms section are a common occurrence. Rapid fouling in slurry pumparound exchangers requires frequent cleanings and added maintenance costs. Coking in the slurry pumparound bed leads to poor product quality, increased column pressure drop, and
shortened run length. However, many chronic problems can be mitigated with innovative designs driven by a proper understanding of the root cause. S lurry P umparound B ed Many FCCs are expected to operate 5-7 years between planned maintenance turnarounds. Modern grid packings have been used in this severe service with success. Even so, there have been times when the combination of high temperature, high liquid rate, and high vapor rate have caused severe coking. Trough distributors have been the go-to device to distribute liquid to the slurry pumparound bed. Special design features are used to mitigate risk of catalyst and coke particle accumulation in the troughs. The features that make the distributor more forgiving also make it more sensitive to liquid gradient and out-of- levelness. Even with the most careful design, slurry beds have experienced premature coking and shortened run lengths. In order to solve old problems, sometimes new thinking is needed. The engineers at Process Consulting Services, Inc. have revamped high severity, highly-loaded slurry pumparound sections with innovative solutions. A new twist on a classic distributor design improves reliability while eliminating inherent problems of old designs. Patented solutions to highly loaded grid-beds offer needed breathing room. Contact us today to learn how PCS designs can improve your FCC.
Coked distributor and grid
3400 Bissonnet St. Suite 130 Houston, TX 77005, USA
+1 (713) 665-7046 info@revamps.com www.revamps.com
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