maximises light olefins, while high REO on zeolite (FCC-a) favours H-transfer reactions, minimising light olefins. Regarding the yield of BTX, Figure 3 highlights different pathways to aromatic formation. In the case of FCC(a), the higher hydrogen transfer rate promoting the forma- tion of naphtha paraffins also increases the rate of alkane dehydrocyclisation, resulting in the highest overall yield of aromatics. In the case of FCC(d), promoting higher yields of light olefins also promotes aromatic formation through oligomerisation of light olefins. The formation of olefins is at the expense of naphtha, resulting in the highest concen - tration of aromatics in naphtha, as illustrated in Figure 4 . The FCC(d) formulation, combining both low REO on zeo - lite and an olefins functionality, allows for maximising light olefins and BTX concentration in naphtha. The impact of the operating conditions, including cat-to-oil and operating temperature, on the light olefins and BTX yields was also investigated by focusing on FCC(d). As per Figure 4, both light olefins and BTX yields can be further enhanced as the cat-to-oil and/or the operating temperature increases. The light olefins yield at 600°C, and a cat-to-oil C/O of 6.0 is rather significant, namely about 59 wt% as C₂=, C₃=, and C₄=, and can be further boosted by using higher severities, such as higher cat-to-oil (for example, >6.0) and/or higher operating temperature (for example, >600°C). Conclusion Plastic recycling has gained attention in the circular econ - omy due to its potential for making the plastics lifecycle more sustainable. As there are challenges to the mechanical recycling of all plastics waste, chemical recycling has been considered a promising alternative as a means to increase the rate of global recycling. Quantafuel produces high-quality pyrolysis from poly - olefins plastics waste, which can be considered in lieu of fossil-based feedstocks, either as co-feeding or standalone alternative feeds to be further cracked in FCC units to pro - duce lower carbon intensity finished products. It has been demonstrated that the FCC catalyst can be fine-tuned to produce more sustainable transportation fuels or chemicals via typical co-processing applications for refiners. The upgrading of this type of pyoil also appears to be a very efficient alternative to produce sustainable chem - icals, such as light olefins and aromatics, for units operating at high severities to produce petrochemical feedstocks. References 1 Hundertmark, T., et al ., 2018, How plastics-waste recycling could transform the chemical industry , McKinsey & Company, 1-11. 2 Lee, J., et al ., 2025, Current methods for plastic waste recycling, Chemosphere , 370, 1-11. 3 Sharuddin, S., et al., 2016, A review on pyrolysis of plastic wastes, Energy Conversion and Management , 115, 308-326. Olav Stadaas joined Quantafuel in 2018 to support the plastic-to-liq - uid initiatives from pilot plants to full-scale operational plants, followed by close cooperation with BASF since 2019. Stadaas earned an MSC in mechanical engineering and has broad experience as a manager in small and larger companies within technology and business develop - ment processes.
Catalytic cracking evaluation of plastic pyoil at 550°C with FCC(a), FCC(c), and FCC(d) at iso-conversion (93 wt%)
FCC(a)
FCC(c)
FCC(d)
Cat-to-oil, wt/wt Hydrocarbon yields H₂, wt%
5.4
6.3
4.3
0.04 0.89 0.52 0.97 1.94 9.45 1.53 6.45 8.42 3.84
0.06 0.75 0.51 1.17 1.26
0.03 0.28 0.27 4.34 2.04
Methane, wt% Ethane, wt% Ethylene, wt% Propane, wt% Propylene, wt% n-Butane, wt% i-Butane, wt% n-Butenes, wt% i-Butylene, wt% Naphtha, wt%
13.04
22.28
0.92 4.59
1.01 2.18
10.42
12.53
5.89
8.27
56.12
52.87
39.09
LCO, wt%
5.73 1.27 2.85
5.93 1.07 1.52
5.84 1.16 0.69
Bottoms, wt%
Coke, wt%
Calculated values Total valuable liquids * , wt% 93.46
94.91
93.24
Total dry gas, wt%
2.42
2.49
4.91
Total LPG, wt%
31.62
36.12
48.31
LPG olefinicity, wt/wt
0.69
0.81
0.89
Total C₄=, wt%
12.26
16.31
20.80
C₃ olefinicity, wt/wt C₄ olefinicity, wt/wt Total light olefins, wt%
0.83 0.61
0.91 0.75
0.92 0.87
22.68
30.53
47.42
* Total valuable liquids defined as LPG + gasoline + LCO
Table 3
zeolite, allows for achieving higher LPG olefinicity due to lower hydrogen transfer reactions and consequently higher olefins preservation compared to FCC(a). FCC(d), with its olefins functionality, allows a further boost to the selectivity of light olefins. FCC(a) promotes hydrogen transfer reactions resulting in higher activity and naphtha and coke yields compared to FCC(c). The olefin functionality in FCC(d) can help to directly convert precursors already present in this pyoil to light olefins (such as C₂=, C₃=, and C₄=), resulting in a lower coke yield compared to FCC(a) and FCC(c). FCC(d) shows fewer valuable liquids due to its higher selectivity to ethylene compared to FCC(c). FCC(d) is fully oriented towards light olefins production and exhibits lower naphtha selectivity compared to FCC(a) and FCC(c) due to its combination of low REO on zeolite and olefins functionality. The selec - tivity towards light olefins could be further boosted while operating FCC(d) at higher severity, such as higher cat-to- oil and/or higher temperature. BTX yields were also assessed with all three catalysts. The BTX yields were calculated according to the naphtha yield multiplied by the concentration of BTX in naphtha measured by detailed hydrocarbon analysis (DHA) illus - trated in Figure 3 . This shows how the yield of light ole- fins follows the expected trend, where the combination of low REO on zeolite and additional functionality (FCC-d)
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PTQ Q3 2025
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