Grace introduces iron-tolerant FCC catalytic solutions

Although the supply and demand imbalance for finished products in 2022 and 2023 has led to robust refining margins across the industry, the long-term market outlook remains highly competitive for refiners. The myriad headwinds facing the industry today are not necessarily new and continue to warrant focused and clear objectives. One of these critical objectives is maximising operating and feedstock flexibility to facilitate rapid responses to market shifts.

With respect to feedstock flexibility, iron poisoning of FCC catalyst has been a challenge for catalyst suppliers, researchers, process licensors, and refinery operators for decades. Many refinery planning and economics departments have had to settle for a suboptimal crude and feedstock strategy to avoid the consequences of iron poisoning in the FCCU. With the advent of tight oils in recent years, these challenges have only been exacerbated for refiners in all regions across the world.

The effects of iron on FCC catalyst performance are becoming more widely understood, owing to increased commercial experience and continued desire to process opportunity feeds ladened with iron. Iron can react with alkali metals, silica, and other contaminant metals to form a dense barrier layer on the surface of the equilibrium FCC catalyst, blocking access to the pores and preventing oil from reaching the catalyst’s active cracking sites. As a result, a classic Fe-poisoned equilibrium FCC catalyst shows nodule formations near the catalyst surface and an instantaneous loss in Diffusivity Index, a measure of the ability for feed molecules to enter the catalyst and undergo cracking reactions. Typically, an operator may realise loss of conversion, reduced bottoms cracking, increased hydrogen transfer reactions, reduced LPG olefinicity, and/or instability in catalyst circulation. To combat these detrimental effects, researchers at Grace have continued to innovate and have introduced new FCC catalyst technologies into the marketplace, the latest of which is MIDAS^® Pro.

MIDAS Pro technology, built on Grace’s workhorse MIDAS^® catalyst platform, has been proven commercially to provide a baseline iron tolerance improvement, as well as a barrier to unexpected feed iron excursions in the FCCU. In multiple commercial applications, MIDAS Pro catalyst demonstrated sustained bottoms cracking performance despite iron excursions to values among the highest in the industry. This improved tolerance has allowed multiple refiners to not only widen their operating window in the FCCU, but also their feedstock selection criteria, which has a positive cascading effect on feed processing flexibility and overall refinery profitability.

In Figure 1 and Figure 2, data from a recent commercial application of MIDAS Pro are shown, indicating the increased added iron level attained, as well as the superior Diffusivity Index at a given added iron level relative to the incumbent catalyst.

Figure 1. The reformulation to MIDAS Pro technology enabled a sustained increase in added iron.

Figure 2. At a given added iron level, Ecat Diffusivity Index is superior for MIDAS Pro technology.

In this commercial example, the refiner was able to process feeds with a higher iron level, while sustaining activity and bottoms cracking in the FCCU. Additionally, the improved pore size distribution and enhanced macro and meso-porosity of MIDAS Pro, as reflected in the Hg-PSD plot in Figure 3 comparing MIDAS Pro Ecat vs Base Ecat, offered enhanced resilience during high iron excursions.

Figure 3. Hg-PSD plot of MIDAS Pro and Base Ecat, portraying the difference in porosity.

Overall, there are numerous causes of FCCU and refinery wide constraints, a prevalent one of which is feedstock contaminants and metals handling. A popular FCC adage states that a truly optimised FCCU operates against multiple constraints at any given time. Such optimisation requires disciplined and cross-functional collaboration among refinery operators, catalyst suppliers, and technology licensors. The use of premium technologies can move the needle even further, pushing beyond base case limits and unlocking significant value for a refiner.

In summary, the future of the refining industry remains bright, but it will continue to be shaped by the healthiest and most strategic refiners. FCC units are expected to represent a key component of future strategies given their unique flexibility to handle diverse feedstocks, including renewable and chemical recycling streams and the new challenges they might bring. As such, expanding and leveraging the full extent of the FCCU operating window – especially with respect to feed metals tolerance – will be vital to optimising refinery profitability over time.

Written by Shankhamala Kundu, Luis Bougrat and Gary Cheng, W. R. Grace & Co.-Conn.

Read the article online at: https://www.hydrocarbonengineering.com/special-reports/12102023/grace-introduces-iron-tolerant-fcc-catalytic-solutions/