Investigation of n-pentane pyrolysis at elevated temperatures and pressures in a variable pressure flow reactor

• Designed and built a variable pressure flow reactor that can operate at pressures up to 4 MPa at temperatures up to 1073 K.
• n-Pentane experiments done over a temperature range 923–1073 K, a pressure range 0.1–2 MPa and residence time 30 ms–40 s.
• Compared experimental data to an existing chemical kinetic mechanism. Used sensitivity analysis to identify key reactions.
• Analysis highlighted that the decomposition of pentane and the production of the main species is dependent on a few reactions.

Thermally cracking fuel in a fuel processing facility or undergoing pyrolysis in the anode channel of a fuel cell can lead to coke deposition. The formation of coke occurs via chemical kinetic pathways that are largely dependent on poly aromatic hydrocarbons (PAHs). The formation of PAH’s largely depends on species which include ethylene, acetylene, butadiene, benzene and toluene. Pentane is a relatively simple structure for modeling purposes, yet large enough that it produces some of the relevant chemistry of real fuels. Experiments were conducted in a newly designed variable pressure flow reactor (VPFR) built to process both liquid and gaseous reactants at pressures to 4.0 MPa and temperatures to 1373 K. The VPFR was initially validated via ethane pyrolysis experiments and comparing the results with existing literature data. Pentane experiments were done over a range of temperatures (923–1073 K), pressures (1–2.0 MPa) and residence times (30 ms–40 s). The product selectivity appeared to be greatest influenced by pressure and level of fuel conversion. Pressure increases ethylene production but has an inverse effect on ethane production. Soot precursors appeared at higher levels of conversion. The results of the experiments were compared to an existing chemical kinetic mechanism with good agreement.