Catalysis 2022 issue

of FCC based faujasites that not only displays significantly increased porosity in the fresh zeolite but concomitantly features enhanced hydrothermal stability over stand - ard mesoporous zeolites and con - ventional stabilised USY zeolites (see Figure 6 ). Zeopore’s technologies have also been successfully applied to ZSM-5- based additives, displaying signifi - cantly increased mesopore surface area and preserved microporosity before and after steam deactiva - tion. This combination of features unlocks benefits, such as increased olefin yields (see Figure 7 ). Hydrocracking The potential of mesoporous zeolite catalysts in hydrocracking is vast. Like FCC-based faujasites, the mes - oporisation of USYs for hydropro - cessing is a core target, yet not the ultimate challenge. For the fragile high-silica faujasite zeolite frame - work, mesoporisation is easily achieved. The challenge is to com - bine the introduction of ample mes - oporosity with the preservation of intrinsic zeolite properties, such as acidity (see Figure 8 ). Zeopore’s high-quality mesop - orised zeolites enable three-way benefits in hydrocracking: gains in selectivity, activity, and stabil - ity. Other secondary benefits are lower hydrogen consumption and improved product quality (cloud point and density). Unlike other technologies, these benefits are feasible for catalysts varying from

Fresh

Deactivated

120

Conventional Zeopore

100

Microporosity Mesoporosity

Figure 7 Porous properties of ZSM-5 catalyst prepared via conventional methods – parent zeolite (orange) and Zeopore mesoporised zeolite (blue)

based on the ongoing shift from fossil to sustainable feedstocks. Also, Zeopore’s catalysts have supe - rior performance for these more demanding biomass-derived feeds than conventional zeolite based catalysts. Alcohol valorisation The production of (biomass- derived) alcohols offers significant opportunities for subsequent cat - alytic upgrading towards olefins and other platform molecules. In alcohol conversions, mesoporous zeolites have proven their value based on an increased resistance towards coke formation. In a case study on methanol-to-propyl - ene with ZSM-5-based catalysts, Zeopore has demonstrated that, in addition to the known stability benefit (lifetimes doubled or more), mesoporisation enables it to gain

low-zeolite content diesel-selective catalysts to high-zeolite content naphtha-selective catalysts. Hydro-isomerisation (dewaxing) Typically, the benefits of mesop - orisation increase as the size of the substrate molecules increases and as the size of the zeolite micropores decreases. Accordingly, in diesel and lube dewaxing using uni- directional zeolites, the benefits are even more pronounced: improved cold flow properties at an unprecedented low diesel loss (see Figure 9 ). Moreover, the reduced degree of cracking con - sumes less hydrogen, the limited LPG formation allows for a higher plant capacity, and gains in hydro - genation potential enable a lowered amount of aromatics in the product. The commercial relevance of dewaxing processes is expected to significantly increase in the future,

(b)

(a)

(c)

Diesel yield

120

100

+7 wt%

Mesoporosity / %

Acidity / %

Conversion / %

Fresh Aged

Figure 8 (a) Mesoporosity and acidity of USY zeolites prepared via conventional methods (orange), standard mesoporisation (grey), and Zeopore (blue) (b, c) Conversion and diesel yield benefits Zeopore brings over the conventional zeolite-based catalyst

Catalysis 2022 47