吡啶萃取对烟煤热解过程焦油生成特性的影响

煤中含有以非共价键结合的可萃取物,煤的萃取物和萃余物热解反应性不同。本研究首先用醋酸消除煤中静电作用力,再以吡啶萃取消除氢键作用力,通过热重和固定床研究了煤萃取物和萃余物的热解特性。相对于原煤,萃取物（E1）的H/C原子比较高,而萃余物（R1）比原煤的孔径有所增大。热重实验表明,萃取物热分解温度低,失重率大;萃余物在485℃之前失重大于原煤,温度高于485℃小于原煤。固定床氮气热解表明,萃取物（E1）的焦油产率和气体比原煤高;萃余物（R1）的焦油产率低于原煤焦油产率。而氢气气氛下,萃取残渣的焦油产率明显高于原煤,这是由于吡啶萃余物具有更开放的孔结构,有利于加氢热解过程氢向孔内扩散,减少了缩聚反应。

Effect of pyridine extraction on the tar characteristics during pyrolysis of bituminous coal

Extensive research has shown that coal has an extractable small molecular compound, which was associated with non-covalent bonding coal molecules. In addition, the reactivity of coal extract and residue is different. In this work, a bituminous coal was acid washed and extracted by pyridine to destroy the electrostatic interactions and hydrogen bonds. The pyrolysis behavior of the extracts and residue was studied by thermogravimetry (TG) and a fixed bed reactor. The H/C atomic ratio for the pyridine extract was significantly higher than that of raw coal, indicating hydrogen-rich components. The pyridine extract (E1) gave a higher tar yield of 44.4%, as well as more gas, while the tar yield of residue (R1) was lower than raw coal in an N₂ atmosphere. However, the residue gave more than two times the amount of tar under H₂ than that of N₂ because developed porous structure was formed by pyridine extraction, which would facilitate hydrogen diffusion into the pore structure and reduce the polycondensation reaction.