15.0
10.0
Stable WABT during production campaign
5.0
0.0
-35
-40
-45
-50
Average product cloud point: -46°C
-55
0
2
4
6
8
10
12
Time on stream (months)
Figure 6 Liquid product cloud point and WABT during a year-long SAF production campaign
for this catalyst are, therefore, well beyond five years. Using residue and waste streams as feedstocks during this campaign resulted in significant concentrations of N-compounds in the feed, which could potentially affect the activity and stability of the HI catalyst. Hence, the observed stability also indicates that the ReNewFine HDO catalyst system upstream was effective in preventing nitrogen slip to the hydroisomerisation stage. During this campaign, total liquid product yields exceeded 90% on a litre product per litre HEFA feed basis. Table 2 presents the relevant properties of the total liquid product, along with the SAF and renewable diesel fractions obtained from it. Fractionation resulted in 74 wt% SAF, which comfortably met all product specifications, while the remaining fraction was high-quality renewable diesel. The challenge
in producing SAF is to maximise the SAF yield compared to renewable diesel while minimising yield loss to renewable naphtha or lighter products through unselective cracking. Severe isomerisation requires higher temperatures, making it even more difficult to prevent the formation of light products. The high yields obtained during this campaign demonstrate the high isomerisation selectivity of the ReNewFine catalyst system. Additionally, this selectivity prevented operational issues such as severe exotherms or excessive product vaporisation caused by uncontrolled cracking. The examples in this article vividly demonstrate the crucial role of the catalyst system in producing SAF from waste and residue oils and fats via the HEFA route. A highly selective HI catalyst is essential for achieving the deep isomerisation and selective cracking necessary for SAF production, without incurring excessive yield loss to light products. However, this catalyst can only operate at its peak efficiency when safeguarded by an effective HDO catalyst system. ReNewFine, ReNewSTAX, and NEXBTL are trademarks of Ketjen.
Total liquid
SAF
Renewable
fraction diesel fraction
product
74 wt% yield
26 wt% yield
Density (kg/m³) Cloud point (°C) Freezing point (°C) Flash point (°C)
775 -46
771
787 -30
-52 40
References S&P Global SAF Market Outlook, February 2025.
Table 2 Average properties of the total liquid product ex HI and the SAF and renewable diesel fractions obtained during a dedicated SAF production campaign
Jaap Bergwerff Jaap.Bergwerff@ketjen.com
www.decarbonisationtechnology.com
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