## 4 LBV of SAFs
### LBV of Bio-jet Fuel  
Due to the abundance of available biomass sources, the variety of bio-jet fuels far exceeds that of synthetic fuels. Plant oil sources (algae, camelina, jatropha, etc. ), animal fats (tallow), and waste oil are the primary raw materials for bio-jet fuel [33; 61]. The compositional standards of bio-jet fuel prepared according to different standard paradigms are not uniform, resulting in significant discrepancies in the lateral comparison of LBV performance in various studies. The LBV values of several typical bio-jet fuels are summarized in Figure 5. At approximately 1 atm and 420 K, the LBV\({}_{\_}\)max of two pure bio-jet fuels are around 62 and 55 cm/s, respectively, both lower than the LBV\({}_{\_}\)max for a blend of microalgae oil and RP-3 (80 cm/s). Furthermore, the LBV\({}_{\_}\)max of these two pure bio-jet fuels occurs at equivalence ratios of around 1.0 and 1.2, which contrasts with the trend observed for conventional aviation fuels. According to Figure 2, the range of LBV\({}_{\_}\)max for Jet A at 1 atm and for 470 K is 78-86 cm/s, the LBV\({}_{\_}\)max (84 cm/s) of bio-jet fuel from amelina also falls within this range, and bio-jet fuel prepared from corn stover lignin exhibits a lower LBV\({}_{\_}\)max (75 cm/s). At 1 atm and 480 K, the LBV\({}_{\_}\)max for a blend of microalgae oil and RP-3 is approximately 90 cm/s. According to Figure 3c, under the same conditions, the LBV\({}_{\_}\)max of RP-3 is only 81 cm/s. Therefore, based on the data from these studies, it is difficult to conclude whether traditional jet fuel or bio-jet fuel has a higher LBV. Apart from the use of different testing methods, it may also be because the production process of bio-jet fuel originates from the laboratory rather than following ASTM standards, or because the prepared bio-jet fuel has undergone component optimization to achieve performance close to that of conventional jet fuel. When various bio-jet fuels are compared to conventional fuel, significant uncertainty is observed, with some bio-jet fuels showing comparable or slightly deviating LBV values. [PERSON] et al. measured the LBV of farnesane (2,6,10-trimethyldodecane), which is produced from sugar using the Bunsen flame method at 473 K, and found LBV values close to those of Jet-A [37]. They proposed a reaction model based on these results, which showed good agreement with actual data in terms of ignition delay times and LBV. [PERSON] et al. determined the LBV of a third-generation biofuel derived from renewable feedstocks (biomass, waste cooking oil, and agricultural wastes) by the spherical flame method, finding  
Figure 5: Illustration of the LBV of several typical bio-jet fuels at atmospheric pressure (P = 1 atm) under temperatures of around 420 K (blue), 470 K (green), and 480 K (red). The LBV data are cited from microalgae oil/RP-3 [62], bio-aviation fuel [63], UOP amelina [33], third-generation biofuel [64], and rice husk fuel [65], respectively. LBV values similar to those of Jet A [64]. Their study indicated that under lean and rich conditions, the LBV is respectively increased and suppressed by chain branching reactions (O\({}_{2}\) + H =OH + O) and chain propagation reactions (and O\({}_{2}\) + H = HO\({}_{2}\) (+M)). [PERSON] et al. investigated the LBV of corn stover lignin via catalytic hydrodeoxygenation (HDO) at atmospheric pressures of 1, 2, and 4 bar and temperatures of 443 and 473 K, revealing lower LBV values for the bio-aviation fuel candidate compared to Jet A-1, RP-3, and n-decane under lean conditions, but higher values under rich conditions [63]. The bio-aviation fuel candidate they adopted contains approximately 67.29 mol% cycloparaffins, and it is believed that a high proportion of cyclic hydrocarbons is the reason for the low LBV. [PERSON] et al. measured the LBV of two high-performance hydrocarbon fuels using the Bunsen burner method at 550 K, finding LBV peak values biased towards rich conditions, resulting in a lower LBV for high-performance hydrocarbon fuels compared to Jet A under lean conditions [34].