Non-oxidative pyrolysis

Our interpretation of these results is summarized in the simplified mechanistic scheme shown in Figure 5. In this scheme the conversion of methane to ethane/ethylene and then to CO2 occurs by a series of consecutive reactions. The relative rates of methane and ethylene activation, and k2 in Figure 5, determine the upper limit of C2 yield. (Since ethane can convert to ethylene readily by non-oxidative pyrolysis and ethylene is more stable than ethane the rate of ethylene activation is taken to be the limiting rate.) The direct conversion of CH4 to CO2 has been ignored. Assuming this rate is negligible is the most optimistic assumption possible as far as catalysis is concerned since conversion of CH4 to CO2 cannot contribute to C2 yield. 

Smith, P.B. Snyder, A.P. (1993), Characterization of bacteria by oxidative and non-oxidative pyrolysis—gas chromatography/ion trap mass spectrometry. Journal of Analytical and Applied Pyrolysis. Vol. 24, No.3, pp.199-210, ISSN 0165-2370. 

Scrap butyl rubber inner tubes represent a source of waste rubber that is easily identified and segregated. Workers in Pakistan [19] have subjected these items to a batch non-oxidative pyrolysis process under both uncatalysed and catalysed conditions. In both cases atmospheric pressure was used, with zinc oxide being used as the catalyst in the catalysed version. The resultant product in both cases consisted of a hydrocarbon mixture and carbon black. The effects of temperature, amount of zinc oxide and reaction time on the yield of the products were studied. The hydrocarbon fraction was assessed as a fuel by carrying out tests such as flash point and aniline point. 

The result is that TGA can only be an indicative technique and other more accurate techniques (e.g. surface absorption of nitrogen - BET method, or iodine adsorption method) should be used to obtain a more definitive identification of the black present in a sample after its recovery by non-oxidative pyrolysis. 

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See also in sourсe #XX -- [ , ]

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