Effect of particle size on pyrolysis characteristics of Elbistan lignite

Thermal behavior and the evolution of char structure during co-pyrolysis of platanus wood blends with different rank coals from northern China

“…Because of its cross-linked structure, lignin decomposed at higher temperature and more slowly than holocellulose [28]. The thermal events during pyrolysis of PZ were mainly composed of four stages: the stage of moisture evaporation, removal of adsorbed gases, and release of low volatile species including mainly low molecular compounds and free radicals in the temperature below 200°C [29]; the initial pyrolysis stage from 286 to 320°C in which decarboxylation reaction may occur; pyrolysis stage between 320 and 600°C during which mainly the decomposition reaction occured; and the last stage at temperatures above 600°C during which polycondensation took place. The pyrolysis temperature range of PZ lignite was consistent with results obtained from pyrolysis of other lignite [16].…”

Pyrolysis of superfine pulverized coal. Part 2. Mechanisms of carbon monoxide formation

“…Hence, the lower-rank superfine pulverized coals with the critical particle sizes take more advantage for inhibiting the NO x formation. On the other hand, chemical reactions as well as physical changes are important for pyrolysis [28]. With further decreases in the particle sizes, the intraparticle mass concentration and temperature gradients are diminished.…”

“…Therefore, the ether and hydroxyl functionalities are the precursors for the high-temperature CO evolution during coal pyrolysis. In addition, the cleavage of heterocyclic oxygen-containing structures might also contribute to the release of this late CO [11,23,28]. These structures split off CO only at high temperatures (%700°C) [15].…”

Combustion and Pollutant Emission Characteristics of Lignite Dried by Low Temperature Air

“…The third peak can be observed at about 900 C. The third region, ranging from 800 to 1000 C, is mainly attributed to the thermal decomposition of mineral matter in lignite, especially carbonates. [39] As seen in Fig. 11a, the mass losses of the dried coals are greater than that of the parent coal, which means that the dried coals have higher volatile yields.…”

“…[37,38] It is known that decarboxylation occurs between 200 and 300 C and then tar formation begins between 300 and 400 C with the dissociation and breakdown of aromatic compounds. [39] The peak temperature representing the maximum mass loss is about 450 C. As the temperature was increased to 500-750 C, the aromatic ring condensation occurred and led to the release of secondary gases and the formation of coke. The third peak can be observed at about 900 C. The third region, ranging from 800 to 1000 C, is mainly attributed to the thermal decomposition of mineral matter in lignite, especially carbonates.…”