Variation of the coal chemical structure and determination of the char molecular size at the early stage of rapid pyrolysis

Poplar wood torrefaction: Kinetics, thermochemistry and implications

“…It was noted that the longer the torrefaction residence time, the elemental compositions of the torrefaction solid residual are closer than coal (a relatively high-quality solid fuel), these observations are in agreement with experimental data of wood briquette torrefaction obtained from Felfli et al [99]. [97] and coals [98] are also included). The energy yields of torrefied solid products decrease linearly with an increasing mass loss of torrefaction solid materials, similar to the study performed by Peng et al [103].…”

“…Figure 10 illustrates the evolution of main elements present in torrefaction solid residual and volatiles (Figure 10(a)), it also depicts the corresponding element ternary diagram of the torrefaction solid residual at different torrefaction periods (Figure 10(b)). For comparison, the results of some herbaceous biomass feedstocks [97] and coals with different ranks [98] were also included in Figure 10. The torrefaction solid residual loses much more Oxygen (O) than Carbon (C), and the corresponding evolution rate of O is much higher than that of C through the release of torrefaction volatiles, especially at the initial stage (0 -30 min at T0 = 25 o C, β = 20 o C min -1 , Tf = 275 o C).…”

“…Figure 10. (a) Evolution and evolution rate of main elements in torrefaction solid residual during poplar wood torrefaction; (b) Element ternary diagram of poplar wood and torrefaction solid residual at T0 = 25 o C, β = 20 o C min -1 , Tf = 275 o C and different torrefaction time (results of some herbaceous biomass feedstocks[97] and coals[98] are also included).…”

Pyrolysis of Low-Rank Coal: From Research to Practice

“…Moreover, because of the conjugated structure, aromatic heteroatom (such as sulfur, nitrogen and oxygen) structures are much more thermostable than aliphatic ones. And it is also reported that the fragmentation progress of LRC is more significant than higher rank of coal [25,26]. The instable structures in the macromolecules of LRC homolytic cleave into radicals, and small molecules are generated with stabilization of these radicals, while the stable structures associated with condensed products remain in char or coke.…”

Chemical and structural characterization of char development during lignocellulosic biomass pyrolysis

“…Transforms infrared (FTIR) spectroscopy. Major findings include the elimination of aliphatic groups at lower temperatures and as heating temperatures were increased, the aromatic functional groups lost their infrared activity resulting in a spectrum with no FTIR peaks(Rutherford et al, 2012;Suliman et al, 2016) Cui et al (2016). used FTIR to extract coal structural parameters which included the fraction of aromatic and aliphatic fractions.…”