Hydrogen-transferring pyrolysis of long-chain alkanes and thermal stability improvement of jet fuels by hydrogen donors

Journal Article · Tue Mar 01 04:00:00 EST 1994 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00027a011· OSTI ID:7207887

Song, C; Lai, W C; Schobert, H H ^[1]

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1. Pennsylvania State Univ., University Park, PA (United States). Fuel Science Program

Hydrogen-transferring pyrolysis refers to the thermal decomposition of hydrocarbons in the presence of hydrogen donors. Relative to the pyrolysis of pure n-tetradecane (C[sub 14]H[sub 28]) at 450 C, adding 10 vol % of H-donor tetralin suppressed n-C[sub 14] conversion by 68 % after 12 min of residence time, by about 66% after 21 min, and by 37% after 30 min. The presence of tetralin not only inhibited the n-C[sub 14] decomposition, but also altered the product distribution. The decomposition and isomerization of primary radicals are strongly suppressed, leading to a much higher ratio of the 1-alkene to n-alkane with 12 carbon atoms and slightly higher alkene/alkane ratio for the other product groups. The overall reaction mechanism for the initial stage of hydrogen-transferring pyrolysis is characterized by a one-step [beta]-scission of secondary radical followed by H-abstraction of the resulting primary radical. Moreover, desirable effects of the H-donor are also observed even after 240 min at 450 C, especially for inhibiting solid deposition. The authors also examined the effect of tetralin addition on the deposit formation from a paraffinic jet fuel JP-8 which is rich in C[sub 9]-C[sub 16] long-chain alkanes, and an aromatic compound, n-butylbenzene. Adding 10 vol % tetralin to a JP-8 jet fuel, n-C[sub 14], and n-butylbenzene reduced the formation of deposits by 90% (from 3.1 to 0.3 wt %), 77 % (from 3.0 to 0.7 wt %), and 54 % (from 5.6 to 2.6 wt %), respectively. These results suggest that, by taking advantage of H-transferring pyrolysis, hydrocarbon jet fuels may be used at high operating temperatures with little or no solid deposition.

• DOE Contract Number: FG22-92PC92104
• OSTI ID: 7207887
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Journal Issue: 3 Vol. 33:3; ISSN IECRED; ISSN 0888-5885
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
023000* -- Petroleum-- Properties & Composition
ALKANES
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
DECOMPOSITION
FUELS
HYDROCARBONS
HYDROGEN TRANSFER
JET ENGINE FUELS
KINETICS
ORGANIC COMPOUNDS
PYROLYSIS
REACTION KINETICS
STABILITY
THERMAL DEGRADATION
THERMOCHEMICAL PROCESSES
YIELDS