Sample size dependence in pyrolysis: An embarrassment, or a utility?

Cellulose Pyrolysis Kinetics: The Current State of Knowledge

“…Likewise, differential scanning calorimetry (DSC) studies have shown small samples of wood to undergo endothermic pyrolysis, whereas samples with larger particle sizes exhibit exothermic pyrolysis (Antal, 1985a). Hancox et al, (1991) propose studies of the effects of a systematic reduction in particle size on pyrolysis chemistry, with the goal of detailing the vapor-solid secondary reactions. In theory, the role of such reactions can be made negligible as the particle size decreases.…”

Effect of Porous and Nonporous Carbonaceous Substrates on Polystyrene Thermal Degradation during Fast CO2 Laser Heating

“…The thickness of the polystyrene film on Glassy Carbon particles is estimated to be 0.75 μm, equivalent to a total average sample weight of 13.2 ng (based on the assumption that polystyrene is evenly coated on each particle). This sample size is less than the 0.5 μg critical sample weight suggested by Hancox and Lehrle et al This indicates little or no transport limitation on the pyrolytic reactions, and implies that secondary reactions occurring due to higher residence time of the primary product in the polymer melt are practically nonexistent . This is also supported by examining product ratios.…”

“…To achieve these conditions, we constructed and tested the CO 2 laser pyrolysis system (shown in Figure ). − Porous (Spherocarb) and nonporous (Glassy Carbon) spherical particles were selected as the carbonaceous substrates, and polystyrene was chosen as the model polymer for these studies. Not only is polystyrene one of the most extensively studied and characterized polymers, − but also it has some degree of structural resemblance to coal in that alkylaromatic “tar” components are produced upon pyrolysis. − Hence, studying the thermal degradation behavior of polystyrene in the presence of porous and nonporous carbonaceous substrates could help shed light on the effect of porosity on the elution of similar products from coal.

1 Schematic layout of the laser pyrolysis system.

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CaCl2-Activated Carbon Nitride: Hierarchically Porous Carbons with Ultrahigh Nitrogen Content for Selective CO2 Adsorption

“…Please note that although the heating protocol (ramp rate = 10 °C/min from 30-750 °C with a 2 hour hold) was kept consistent between the TGA measurements and material synthesis, the batch sizes for the TGA-DSC and RGA analyses were necessarily orders of magnitude lower than those used in the larger-scale tube furnace, so artifacts relating to heat transfer may exist. [57][58][59][60] The TGA traces reveal a significant mass loss at around 130 °C (Figure 2a) with corresponding endothermic peaks observed by DSC ( Figure 2b) and increases in H2O (m/z = 18) signal from RGA ( Figure 2c). We attribute this event to the incongruent melting and decomposition of CaCl2*2H2O, [61][62][63] as evidenced by the increase in magnitude of this feature with increasing CaCl2*2H2O weight ratio ( Figure 2a-c and Figure S2).…”