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借助分子反应动力学模型,基于Reax FF力场,从原子层面模拟研究了高温作用下纤维素单体纤维二糖的裂解机理。模拟结果表明,纤维二糖、1-吡喃环和4-吡喃环初始键断裂的位置分别集中在O′4-O,C5-O5和C1-O5,C′5-O′5处。纤维二糖继续分解生成了乙醇醛(CH2O H C H O)、甲酸(C H2O2)、C O2、自由基(C H O2)、1,2-二羟基乙烯(CHOH=CHOH)、H2O以及其他小分子碎片。其中乙醇醛主要是由两个吡喃环上第5个位置上的C和O原子从环上脱落形成的。甲酸和CO2多是由O′1-O′5从4-吡喃环上断裂形成。自由基CHO2由甲酸脱氢生成,也会由C1-O5从1-吡喃环上脱落生成。1,2-二羟基乙烯主要是由4-吡喃环上的两个C原子同时脱落生成。H2O主要由不同分子上的-OH和-H脱落后结合形成。裂解小分子产物可作为新的微观特征量,在变压器过热故障诊断中具有潜在应用价值。
Based on the molecular reaction kinetics model and the Reax FF field, the pyrolysis mechanism of cellulose monomer disaccharide was simulated from the atomic level. The simulation results show that the cleavage positions of the initial bonds of cellobiose, 1-pyran and 4-pyran are respectively at O’4-O, C5-O5 and C1-O5, C’5-O’5. Cellobiose continues to decompose to form CH2O H C H O, C H2O2, C O2, C H O2, 1,2-dihydroxy ethylene (CHOH = CHOH), H2O and other small molecule fragments. Among them, glycolaldehyde is mainly formed by the exfoliation of the C and O atoms at the 5th position of the two pyran rings from the ring. Most of formic acid and CO2 are formed by the cleavage of O’1-O’5 from the 4-pyran ring. Free radical CHO2 is formed by the dehydrogenation of formic acid and also formed by the exfoliation of C1-O5 from the 1-pyran ring. 1,2-dihydroxy ethylene is mainly generated by the simultaneous removal of two C atoms on the 4-pyran ring. H2O is mainly formed by the combination of -OH and -H on different molecules. Cleavage of small molecular products can be used as a new micro-features of the transformer overheating fault diagnosis has potential applications.