50 55 65 60 75 70 80 85
35 40 50 45 60 55 65 70
0.00 0.05 0.15 0.10 0.25 0.20 0.30 0.35
1.0
2.0
3.0
4.0
5.0
1.0
2.0
3.0
4.0
5.0
1.0
2.0
3.0
4.0
5.0
Cat to oil
Cat to oil
Cat to oil
VGO feed
PDPO A
PDPO B
2.5
0 1 3 2 5 4 6
15 10 25 20 30 35
2.0
1.5
1.0
0.5
0 5
0.0
1.0
2.0
3.0
4.0
5.0
1.0
2.0
3.0
4.0
5.0
1.0
2.0
3.0
4.0
5.0
Cat to oil
Cat to oil
Cat to oil
Figure 4 Conversion/yield responses for VGO and PDPO A and B feed samples from SR-SCT MAT testing
that contribute to reducing the carbon footprint. With its commitment to a sustainable world and the vision to be a global energy company that relies on innovation, efficiency, and respect to create sustainable value in the service of soci- etal progress, 2 Repsol believes that the current energy tran- sition should be urgently rethought and a new, fairer model set up so as to involve all of society and leave no one behind. 3 In connection with the company’s vision for the energy transition, Repsol is considering the potential of process- ing lower carbon intensity feedstocks in FCC units. Such feedstocks can be of biogenic origin or waste-derived feedstocks. Repsol and Grace collaborated on the assessment of yield structure effects of waste plastics-derived feedstocks. The refining company provided two plastics-derived pyrol - ysis oil samples (PDPO A and PDPO B) to support an initial techno-economic assessment (TEA) of processing such feed streams in an FCC unit (see Table 1 ). Though unconventional feedstocks like bio- or waste-de- rived feed streams are co-processed in the refinery, the yield structure from such feed streams is of high interest in assessing the respective margin uplift. In most cases, pilot plant co-processing experiments in blends with fossil feed components are performed to assess the incremental yields from the alternative feed component. 4 However, testing the alternative feedstock pure allows for similar information, if not limited by processing challenges in FCC pilot plant equipment. Test programme Waste plastics, when cracked, might yield more light olefins or aromatic compounds depending on the polymer type. To evaluate the crackability and resulting yield effects of cracking the plastics-derived pyrolysis oil samples, Grace’s proprietary single-receiver short-contact microactivity test
unit (SR-SCT MAT) 5 was selected. The SR-SCT MAT unit has proven its versatility in screening unconventional FCC feedstocks where impacts on testing equipment and pro- cess cannot be ruled out. The respective samples of PDPO were compared to a typical vacuum gas oil (VGO) reference feed and converted in the SR-SCT MAT unit using a standard equilibrium cata- lyst sample from a VGO processing FCC unit. Test results The catalytic testing of the pure PDPO samples in compar- ison to a typical VGO highlights the different nature of the
SR-SCT MAT results from VGO and PDPO A and B samples at constant C/O
Standard VGO
PDPO A
PDPO B
Conversion (wt%FF) Dry gas (wt%FF) Propylene (wt%FF)
62.6
79.5
79.3
0.9 3.6 2.7 1.2
1.0 3.6 1.6 1.3
1.3 4.7 3.2 2.2
i-C 4 (wt%FF) i-C 4 = (wt%FF) LPG (wt%FF)
12.4
10.7
16.5
LPG olefinicity (%) Gasoline (wt%FF)
71
78
74
47.3 18.6 18.9
64.2 15.4
57.8 16.6
LCO (wt%FF)
Bottoms (wt%FF)
5.1 3.6
4.1 3.7
Coke (wt%FF) CO x (wt%FF) G-CON RON G-CON MON
1.9
0.03 88.8 78.4
0.29 84.7 76.0
0.09 84.9 74.9
Gasoline benzene Content (wt%)
0.2
2.7
0.3
Table 2
17
Catalysis 2025
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