Detailed modeling of soot formation in hydrocarbon pyrolysis

Experimental study of soot formation from a diesel fuel surrogate in a shock tube

Shock-tube pyrolysis of chlorinated hydrocarbons: Formation of soot

Formation of carbon nanoparticles from the gas phase in shock wave pyrolysis processes

The soot formation in the pyrolysis of benzene/acetylene mixtures and acetylene/hydrogen mixtures diluted in argon was measured behind reflected shock waves using a light absorption technique. For this process, the induction period τ, the soot growth rate constant kf, and the soot yield SY were determined. The experiments were performed in the temperature range between 1560 and 2580 K at pressures of 6 and 60 bar, for different carbon concentrations (1–16×10−6 mol/cm3) and different ratios of the components. For the benzene/acetylene mixtures, the induction times did not show a significant effect related to pressure or mixture ratio and were placed between the induction times for the pure substances. Increasing the benzene/acetylene ratio considerably increases the soot growth rate constant kf at high temperatures. The previously observed bell shape of the soot yield curves as a function of temperature could be confirmed for all mixtures, with maximum soot yields at a temperature of about 1800 K. The soot yield data obtained for benzene/acetylene mixtures show a remarkable synergistic effect. Increasing the pressure or the benzene/acetylene ratio in benzene-rich mixtures decreases the soot yield. In the case of acetylene/hydrogen mixtures, a considerable suppressive influence of the hydrogen additive on the soot yield was observed. Soot particle diameters were determined by transmission electron microscopy and can be described by a narrow, log-normal size distribution function. The average particle diameters are in the range of 20±5 nm for all conditions of temperature and pressure employed in this study and they show a tendency to increase with increasing carbon concentration. Assuming spherical particles, final particle number densities in the range of 1011–1013/cm3 were obtained.

A.J. Gosling

Papers

A shock-tube study of induction times in the formation of carbon particles by pyrolysis of the C2 hydrocarbons