PTQ Q1 2025 Issue

Petrochemical integration Refineries can install downstream units such as olefin conversion units (OCUs), fractionators or propane dehy - drogenation (PDH) units that utilise the lighter products generated from the FCC. Another interesting integration is with steam cracking units (SCU) since ethylene produced by FCC can be recovered, while ethane can be further con - verted to ethylene in the SCU. Modifications to piping and the addition of heat exchangers may also be necessary to connect these units effectively to the existing FCC unit. This integration allows for a more seamless transition from refining to petrochemical production, effectively creating a more versatile and adaptable processing facility. Coprocessing biofeedstocks or lighter hydrocarbons alongside conventional feeds in the FCC unit can diversify the product slate. This method not only helps in meeting reg - ulatory requirements for renewable content but also allows for the production of unique petrochemical intermediates. Alternative feeds often require dedicated storage systems. Additional equipment modifications could include enhancing feedstock pretreatment systems to accommodate biofeed - stocks or lighter hydrocarbons. This might involve upgrading pumps and heat exchangers to handle different viscosities Coprocessing biofeedstocks or lighter hydrocarbons alongside conventional feeds in the FCC unit can diversify the product slate and properties of the new feedstocks. Additionally, FCC licensors have unique equipment modifications they can recommend for co-processing, particularly around how the alternative feedstocks are injected into the FCC. Implementing advanced process control systems can optimise the FCC unit’s performance in real-time. These systems can adjust parameters dynamically based on feed - stock variations and desired product specifications, maxi - mising yield and minimising waste. Many advance control systems are already available today in most refiners, such as real-time monitoring tools and automated control systems. This includes the installation of advanced sensors for tem - perature, pressure, and composition analysis to enable real- time adjustments and optimisation of the cracking process. Upgrades Advanced distributed control systems (DCS) upgrades can dynamically adjust operational parameters based on feed - stock characteristics and desired product yields, while upgrad - ing heat exchangers and integrating heat recovery systems can improve FCC unit energy efficiency. By capturing and reusing heat generated during the cracking process, refiner - ies can reduce overall energy consumption and enhance the economic viability of producing petrochemical products. Continuous investment in R&D can lead to the discov - ery of new catalysts, processes, and technologies that can further enhance FCC performance and its integration with

petrochemical production. Investments in new pilot plant equipment, testing equipment or modifications to existing designs are often needed to support new R&D innovations. By focusing on these upgrade strategies, refineries can - not only boost their FCC unit’s efficiency but also enhance their capability to produce a broader range of valuable pet - rochemical products, aligning with market demands and economic trends. A Carel Pouwels, Global FCC Specialist Light Olefins, carel.pouwels@ketjen.com, Ketjen For petrochemical integration, the maximisation of light olefins by the FCC unit is essential. Within a given unit con - figuration, the first choice is to enhance process conditions that maximise unit severity. Maximising reactor outlet tem - perature is one of the first independent process variables to consider; preferably, the temperature is enhanced to the range of 545-550°C. More extreme process conditions can be applied when the FCC unit is upgraded to so-called ‘high-severity’ FCC units, whereby reactor temperatures up to 600°C are possible. Depending on the metallurgy, a revamp might be needed. Due to the increased dry gas and LPG production, the refin - ery needs to address the wet gas compressor handling too. If not yet present in the current downstream configuration, the refinery needs to expand with deC2, deC3, and deC4 recovery units while also building a C₃ splitter to make chemical-grade propylene. Next to the enhanced severity by a higher reactor tem - perature, conversion can also be enhanced by increased catalytic cracking reactions through more catalyst circula - tion (or cat-to-oil ratio). Consequently, more gasoline mol - ecules are generated, which can be cracked to light olefins. Note, however, that hydrogen transfer reactions will also increase and can negatively impact C3=/LPG. The key to a high olefins yield is control of the various competing reac - tions. Hence, the reduction of hydrocarbon partial pressure through enhanced dispersion and lift steam is also of impor - tance. This way, light olefins are preserved, and reactions to paraffins by unwanted hydrogen transfer are minimised. While dedicated unit hardware and process conditions for high-severity operations are needed, the third element of importance is the FCC catalyst that is optimised for such application. While every FCC unit with its specific feed is unique, it thus requires a unique catalyst solution, prefer - ably from a repository of expertise with a wealth of industrial experience in high-severity FCC applications, ranging from the lightest to the heaviest feedstocks. With decades of sup - ply to various FCC units of all licensors, Ketjen’s max propyl - ene catalysts AFX and Denali AFX with optional usage of its DuraZOOM-MA additive, have achieved record olefins yields. Ketjen’s new ZSM-5 investment at its Bayport site will sup - port the industry in this move to petrochemical integration. A Fu-Ming Lee, Principal Author, fmlee@shinchuang. com, Shin Chuang Technology Co., Ltd, James Esteban, Sr Technical Manager, James.Esteban@unicatcatalyst. com, Unicat Catalyst Technologies, LLC To further upgrade the FCC unit for enhanced petrochemical

PTQ Q1 2025