US EPA

6151343 

Journal Article 

Soot formation during isothermal pyrolysis of carbon tetrachloride and methane-carbon tetrachloride mixture 

Shurupov, SV; Tesner, PA 

1998 

0 

Symposium (International) on Combustion
ISSN: 0082-0784 

27 

1 

1581-1588 

10.1016/S0082-0784(98)80567-5 

http://www.sciencedirect.com/science/article/pii/S0082078498805675
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Soot formation during near isothermal pyrolysis of carbon tetrachloride for the nominal temperatures of 1423–1623 K, as well as of methane-carbon tetrachloride mixture at 1573 K, was investigated. The induction periods of soot formation from carbon tetrachloride were measured. Equations to calculate the induction period of soot formation (τind, s), the soot particle number density (N, cm−3), and the soot surface area (Ar, m2/g) were obtained for carbon tetrachloride as follows: τind=(4.5±0.2)×10−9 [CCl4]−0.9 exp(18,700/T) N=(5.5±0.5)×1023 [CCl4] exp(−47,000/T) Ar=(7.0±0.5)×105 exp(−15,700/T) The apparent activation energy of soot aerosol formation during pyrolysis of CCl4 was found to be 390 kJ/mol, a value higher than activation energies obtained previously during isothermal pyrolysis of other hydrocarbons. The high apparent activation energy of soot aerosol formation during pyrolysis of CCl4 can be attributed to radicals generation and validates the free-radical mechanism of soot nucleation. The sooting tendency of CCl4 was shown to be seven times higher than that of methane when pyrolyzed at 1623 K and resulting in the same soot yield (i.e., 60 wt. %). Inhibition of soot particle nucleation was observed during isothermal pyrolysis of CCl4/CH4/He mixtures. As a result, soot particle nuclei were generated by CCl4 only, whereas methane was consumed by the particles during heterogeneous growth.