Comparison of the Synergistic Effects of Hybrid Hydrogen Donors Towards Stabilization of Paraffinic Jet Fuels in the Pyrolytic Regimes Under Batch and Flow Conditions

摘要

Commercially available aviation fuels are high in paraffins, resulting in poor thermal stability at high temperatrues due to their tendency to crack under pyrolytic conditions (1,2). Hydrogen donors have beed found to stabilize the jet fuels by terminating the propagation of the free radical from thermal cracking (3,4). The pyrolytic cracking of paraffins generates both primary and secondary free radicals, where a certain hydrogen donor may favor the interaction with onlyone type of free radical.This has been indicated previously, where the effects of hydrogen donors, such as benzyl alcohol (BA) and 1,2,3,4-tetrahydro-1-naphthol (THNol), on the product distribution of pyrolytic stressed n-tetradecane were studied in batch conditions in the temperture range 425 to 475 deg C (5). Benzyl alcohol was found to reduce the amount of n-alkane cracking products ,while THNol greatly reduced the 1-alkane. Based on our previous research on radical formation (1,3) this was attributed to the observation that BA appears to target primary radicals and, correspondingly, the targeting of THNol towards secndary radicals. It was further shown that under batch reactor conditions at 450d and 475 deg C, the use of hybrid hydrogen donors produced a synergistic effect towards an improved thermal stability of the n-tetradecane (6). However, it is questionable if the previous findings using batch cnditions and isothermal stressing times of around 30 minutes reflect the actual beahvior during flow conditions. Accordingly, this paper focuses on the potential of hybrid hydrogen donors for enhanced pyrolytic stabilization of paraffinic compounds typical for jet fuels under flow conditions. Hybrid of benzyl alcohol with 1,2,3,4-tetrahydronaphth-1-ol has been studied, and the synergistic effects upon n-tetradecane has been characterized.