PTQ Q3 2025 Issue

Efficient separation technologies

A comprehensive strategy involving electrostatic precipitators when upgrading FCC and resid FCC units, leading to reduced energy consumption

Victor Scalco General Atomic Electromagnetic Systems Clifford Avery Ketjen

A s global demand for energy continues to surge, the refining sector is confronted with the dual challenge of meeting escalating demand while simultaneously reducing carbon emissions. Increased emissions and energy loss are realities when driving the FCC units at high severity to produce propylene for petrochemical production. Refiners are actively developing new solutions to decar - bonise this process and the finished products, such as transportation fuels or commodity chemicals, as part of this energy transition. As a result, refiners are now exploring the co-feeding of alternative feedstocks, including renewable and recyclable oils, as a means of lowering the carbon foot - print of their final products. Given its inherent flexibility, the FCC process has potential to lower the carbon intensity in this effort. However, these new feeds still present challenges, such as additional con - taminants, instability, and miscibility issues, and elevated acidity that can lead to a variety of operational challenges in an FCC unit.10 On the path to achieving carbon neutrality, global demand for crude oil-based gasoline and diesel is expected to decline significantly, thus forcing most refineries to shift to producing more petrochemicals, including liquid renew - ables, to remain profitable while maintaining the focus on decarbonisation. This article will discuss several challenges in the path to decarbonisation, shifting away from transpor - tation fuels within increased propylene demand by means of the FCC unit process.7 , 10 Improving efficiency to optimise yields Upgrading the FCC unit can significantly enhance the inte - gration of petrochemical processes within refineries. The unit primarily converts heavy petroleum feedstocks into lighter, more valuable products like gasoline and diesel. However, by implementing specific upgrades, refineries can optimise the FCC unit to produce higher yields of pet - rochemical feedstocks, improving overall operational effi - ciency and profitability. Implementing advanced process control systems can optimise the FCC unit’s performance in real-time. These systems can adjust parameters dynamically based on feedstock variations, desired product specifications, and product economics, minimising waste as a result to support the refineries’ net-zero goal. Benefits can also be found by upgrading heat exchangers and integrating heat recov - ery systems not only to recover heat energy losses but to

improve FCC unit energy efficiency. By capturing and reus - ing heat generated during the cracking process, refineries can reduce overall energy consumption and enhance the economic viability of producing petrochemical products.3 Another option in support of decarbonisation and increasing profits from the production of propylene is cat - alyst selection. Choosing advanced catalysts that are more selective towards lighter olefins, such as propylene and ethylene, can significantly increase the output of petro - chemical precursors while concentrating on the reduction of emissions. Maximising catalyst accessibility, which is a measure of how easily heavy oil molecules can navigate the catalyst pore structure to find active cracking sites, will result in improved primary products such as improved liq - uid petroleum (LPG) olefinicity, increased gasoline selectiv - ity, and increased light cycle oil (LCO)/slurry ratio. Reducing the rare earth on zeolite (REO/Z) will result in less hydrogen transfer and increase gasoline octanes and LPG olefinicity; however, simply reducing the REO/Z without extensive knowledge of the FCC operations and catalyst system is not wise. A thorough understanding of the FCC regenerator severity and underlying catalyst sys - tems incorporated when designing the optimum REO/Z is required. A well-designed active matrix can reduce unde - sired products like slurry and improve the primary products mentioned earlier. Mobil invented the ZSM-5 zeolite in the 1960s to increase conversion. ZSM-5 is a shape-selective zeolite known to centre-crack gasoline olefins to desired petrochemical products such as propylene, butylene, and, sometimes, eth- ylene. Catalyst companies, like Ketjen, have incorporated ZSM-5 into FCC catalyst since the early 1980s.11 Since then, they have been able to improve the use of ZSM-5, other shape-selective zeolites, and FCC catalyst synergies in support of petrochemical production. Catalyst fami - lies were developed to maximise propylene in support of increased efficiency and reduced losses. These shape-se - lective zeolites are now a common component for max - imising petrochemical precursor feedstocks in the refining industry. Focusing on catalyst alone is not complete with - out looking at the FCC optimisation and riser efficiency. Modifying the FCC unit’s riser section allows for better catalyst distribution and contact time with the feedstock. A design that promotes turbulent flow can enhance cat - alyst effectiveness by improving the distribution of cat - alyst within the unit. Modern maximum propylene riser

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PTQ Q3 2025

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