低阶煤与麦秆共热溶的协同效应

Study on synergistic effect of co-thermal dissolution of wheat straw and low-rank coal

通过对两种低阶煤与麦秆共热溶可溶物的分析,研究了二者在共热溶过程中的协同效应。以单一物种热溶解收率计算出的煤与麦秆混合样品的理论溶出质量低于实验溶出质量,说明两种煤与麦秆在热溶过程中存在协同效应,麦秆在热溶过程中受热分解可以产生大量的自由基,促使煤分子在低温下分解,从而提高热溶解收率。通过气相色谱-质谱联用仪分析发现,麦秆热溶可溶物以含氧类化合物为主,推测麦秆热溶过程中可以产生苯氧基自由基,苯氧基自由基进攻煤分子结构,加快煤的解聚;同时,在煤单一热溶和共热溶产物中也检测到大量的酚类化合物,这主要是乙醇中的O亲核进攻煤中的C-O键的结果。轨道阱质谱分析发现,麦秆可以促进低阶煤中的O、ON、ONS类杂原子化合物从煤的主体结构中剥离。

The synergistic effect between coal and wheat straw in the co-thermal dissolution process was studied through the analysis of the co-thermal soluble matter of two types of low-rank coal and wheat straw.The theoretical solute content of the mixed coal/straw samples calculated from the single species thermal dissolution rate was lower than the experimental solute content,indicating there was the synergistic effect between the two types of coal and straw in the thermal dissolution process.The thermolysis process could generate a large quantity of free radicals via the thermal dissolution of straw,promoting the decomposition of coal molecules at low temperature,thus enhancing the thermal dissolution yield.Gas chromatography-mass spectrometry(GC/MS)analysis showed that the thermal dissolution soluble substance of wheat straw was mainly the compound containing the oxygen.It was assumed that phenoxy radicals could be generated during the thermal dissolution process of wheat straw,which attacked the molecular structure of coal and accelerated the depolymerization of coal.Meanwhile,phenolic compounds were also detected in large quantities in the coal single dissolution and co-dissolution products,which was mainly a result of the O nucleophilic attack of ethanol on the C-O bonds in the coal.Orbitrap-MS analysis showed that straw could promote the stripping of O,ON and ONS heteroatomic compounds from the main structure of coal.