PTQ Q1 2023 Issue

grassroots projects rather than revamps of existing units because of their size difference. For the same reason, the possibility of repurposing existing facilities to construct a WPPO cleaning/conversion facility will be limited. Despite the small size of the contaminant/treatment unit, the variability and (un)availability of the WPPO feedstock could pose a significant operational concern. The waste plastic source will strongly influence unit performance, with some generating olefinic paraffins and others pro - ducing aromatic products, which may be less suitable for certain applications (such as ethylene cracking). Therefore, the refiner should be well aware of both the quality of the WPPO and the risk of disruptions in supply. Q Is it possible that refiners could be overlooking some practical solutions to increasing FCC olefins yields, such as in the gas plant/recovery section? A Michael Allegro, Technical Services Specialist, BASF, For C 3 s, propylene splitters are well-established solutions that most units concerned with C 3 = recovery have likely investigated. For C 4s, most units interested in olefin recov - ery have at least conducted a paper study to determine if a separations solution would be economical. An opportunity for optimisation could be for customers to pay closer atten- tion to ‘lost’ olefins. A potential opportunity for further recovery efforts could be that of ethylene. Many feel that FCCs do not produce enough C 2 = for it to be worth recovering. A future shift in product economics could lead to more attention being paid to fuel gas olefinicity. A Bani Cipriano, Segment Marketing Manager, Light Olefins and Stephen Amalraj, Principal Technologist,, W. R. Grace The yield of light olefins from the FCC can be increased by optimising different FCC process variables, including riser operating temperature (ROT), injection of ZSM-5 addi - tives, hydrocarbon partial pressure, and the recycle of light naphtha, C 4 or oligomer streams into the FCC. Increasing the yield of light olefins increases the load on the wet gas compressor (WGC) and the gas plant. The FCC unit can realise maximum value within unit con - straints by optimising the appropriate variables, and it is important not to overlook catalytic solutions to these con- straints. For example, by increasing the yield of light olefins via ZSM-5 additives versus ROT increase, it is possible to make more light olefins per unit of dry gas production and, The yield of light olefins from the FCC can be increased by optimising different FCC process variables

therefore, for a given unit limitation on the WGC and the gas plant. Furthermore, in high metals applications, using an appropriate coke-selective catalyst with metals trapping functionality can result in lower H 2 make, which further offloads the WGC and gas plant. In both cases, an increase in recovery of light olefins is enabled. As the cost of pro - pylene production from the FCC is lower than other pro- pylene production routes, the use of catalytic solutions or minor revamps to overcome the gas plant handling capac- ity are effective ways of realising the maximum value from the FCC. A Mel Larson, Manager, Strategic Business, Becht, mlar - This is a compound question of FCC yield and recovery. On the yield front, most units are bounded by the wet gas compressor and subsequent recovery capacity. The value and recovery of olefins are regionally specific. In the US, the difference depends on economical access to chemi- cal infrastructure for propylene vs alkylation. The US Gulf Coast has been maximising recovery within existing hard- ware and cooling limits for decades. It is the opposite in the EU market, as LNG prices have been driving plants to fuel more LPG, be it saturates or olefins. One major in the EU stated it had reduced LNG demand by 40% by fuelling LPG components. Thus ultimately, the issue is the value of olefin processing, including petrochemicals, alkylation, and/ or cat poly plant (there are a few left), and it is not a one-size-fits- all solution. Q Under what conditions do you see opportunities with the upgradation of distressed refinery products (such as vacuum resid) to higher value outlets? Are these oppor - tunities primarily outside the fuels market? A Fu-Ming Lee, Maw-Tien Lee, and Tzong-Bin Lin, all Senior Consultants, Shin-Chuang Technology, and Ricky Hsu, Founder, International Innotech, Inc., ricky_hsu@ A supercritical solvent extraction process combining an anti-solvent with multicomponent phase equilibria is suc - cessfully used to separate oil and asphaltenes in vacuum resid commercially. The supercritical or near-critical solvent used in the process exhibits key favourable characteristics for separating asphaltenes from residue:  Unique solvent behaviour, vapour density, and diffusiv - ity, which enhance asphalt phase separation.  Facilitated turbulent mixing of petroleum feedstock and solvent, which enhances mass transfer. ( Refer to: Chung, W., et al, Asphaltene removal technology produces novel cement water- proofing additive, Hydrocarbon Processing , Sep 2021 ). Upon removal of the asphaltene portion, the process produces a high yield of deasphalted, decontaminated, and decarbonised oil suitable for conventional packed-bed hydroprocessing. The novelty of the proprietary process is its unique ability to produce solid, easy-to-handle, virgin, granular asphaltenes, which can be applied to a variety of new uses and allow for the further diversification of the


PTQ Q1 2023

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