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• How can the FCC unit be upgraded to benefit petrochemical integration?

  Feb-2025

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Answers

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• Fu-Ming Lee, Shin Chuang Technology Co Ltd, fmlee@shinchuang.com

  To further upgrade the FCC unit for enhanced petrochemical integration, refiners can leverage a variety of advanced catalysts and technologies, including Magnetic Advanced Filtration System (MagAFS) and drop-in FCC catalyst additive solutions. The following case summary focuses on a technology aimed at slurry oil (SO) upgrading. SO is one of the major FCC unit products, but with low quality and very limited applications, mainly due to its significant content of small catalyst fines (3,000-6,000 µg/g).

  Worldwide SO production from FCC units is huge in quantity. For example, even 25 years ago, FCC units in China alone generated 5 million tons of SO annually. Therefore, the potential benefits of upgrading SO for petrochemical and fuel applications are substantial.

  Small catalyst fines, mostly smaller than 20 µm (10-6m), in SO are extremely difficult to remove. Conventional methods, such as gravity sedimentation, centrifugal separation, filtration, and electrostatic precipitation, are ineffective for fines removal, especially nanometer size (nm, 10-9m) particles. The development of an effective process for removing catalyst fines from SO to upgrade its quality to transportation fuels and improved petrochemical applications is not only profitable but also environmentally preferred.

  MagAFS technology has been developed to remove particles larger than 50 nm. The tests were conducted in a lab UMF unit consisting of two magnetic filtration chambers connected in series. Typical compositions of the tested SO are listed in Table 2.

  SO was fed through the lab unit at a controlled flow rate. Treated SO samples at the exit of the first and second chambers were collected for particle size distribution (PSD) analysis. Samples of solid particles removed by the first and second chambers were also collected for PSD analysis. Focusing on the nm size particles, PSD of the original SO (SO-O), treated SO (SO-1), and duplicate treated SO (SO-1A) are given in Figure 1. It shows that with original SO (SO-O), more than 64% of the solid particles were larger than 6,000 nm (or 6 µm). Only particles smaller than 44.3 nm were left in treated SO (SO-1). The result was confirmed by PSD in the duplicate treated SO (SO-1A).

  Further details of the operation are revealed in Figure 2, where SO exiting the first chamber contained mainly 6-500 nm particles, but still had 20% 6,000+ nm particles. SO exiting second chamber contained only 9-44 nm particles (no 6,000+ nm particles). Most larger particles (2,600-6,000+ nm [63.3%]) were removed by the first chamber. Smaller particles (800-6,000+ nm [33.4%]) were removed by the second chamber. Figure 3 compares the PSD of the original (SO-O), treated (SO-1), and duplicate treated (SO-1A) slurry oil, based on the analysis of all samples collected from the experiments.

  The result confirmed that any solid particles having a size larger than 50 nm (44.3 nm) were successfully removed from the slurry oil by MagAFS process technology. It is also possible to provide low-cost and convenient on-site testing by installing a small portable MagAFS unit through a slip-stream connection without disruption to normal FCC unit operations.

   

  Jan-2025