【作者】 刘波；

【导师】 郭欣；

【作者基本信息】 华中科技大学 ， 新能源科学与工程， 2023， 硕士

【摘要】 生物质热解技术可清洁高效的将生物质转化为生物油和高价值的化学品,但生物质高含氧量导致生物油具有低热值、高粘度,强腐蚀性等缺点。生物质与废塑料共热解可以改善生物油的质量、处理城市废弃物并提高资源利用效率。本文对纤维素（CE）与高密度聚乙烯（HDPE）进行实验与模拟研究对共热解协同机制进行深入探究。主要研究内容如下:（1）利用热重分析技术,研究了CE与HDPE共热解的热解特性,发现在共热解过程中可能存在协同作用,并确定了快速共热解的实验温度。在管式炉反应器中,对CE与HDPE进行快速共热解实验,研究了热解温度CE与HDPE对不同混合比例共热解相互作用的影响。结果表明快速热解温度越高共热解作用效果越强,随着温度的增加,气体产率11.1%提高到42.8%,液态产率从76.7%下降到49.3%。生物油分析结果表明共热解促进左旋葡聚糖等含氧物分解,从而提高焦油的质量。（2）升温速率是影响热解二次反应的重要因素,为了研究升温速率对CE与HDPE不同混合比例共热解相互作用的影响以及不同升温速率的热解特性,在管式炉中同时进行慢速共热解和快速共热解实验。结果表明慢速共热解可以提高液态产率,并降低气态产率和焦炭产率。在CE与HDPE为1:3时,慢速共热解相互作用最强烈,此时液态产率为95.4%。而快速共热解抑制焦油产生,在CE与HDPE为3:1时,快速共热解相互作用最强烈,此时液态产率与气态产率分别为49.3%和42.8%。（3）采用ReaxFF MD模拟研究CE与HDPE共热解反应机制。结果表明共热解时,CE分解为左旋葡聚糖等C₆产物并脱水形成羰基,同时产生大量的OH自由基并在9ps达到峰值然后快速下降,说明OH自由基反应剧烈,能促使HDPE断裂并与生成烯烃反应生成醇,HDPE产生的H自由基促进重油和轻油发生裂解产生大量CO等气体,从而减少液态产率并提高气态产率。更多还原

【Abstract】 Biomass pyrolysis technology can cleanly and efficiently convert biomass into bio-oil and high-value chemicals.However,the high oxygen content of biomass leads to bio-oil with low calorific value,high viscosity,and strong corrosiveness and other disadvantages.Co-pyrolysis of biomass and waste plastics can improve the quality of bio-oil also can effectively treat the waste to improve resource utilization efficiency.In this paper,experimental and simulation studies on cellulose and high density polyethylene were conducted simultaneously to investigate the interaction mechanism of co-pyrolysis in depth.The main studies are as follows.（1）The pyrolysis characteristics of the co-pyrolysis of cellulose and HDPE were investigated by using thermogravimetric analysis technique.It was found that there might be a synergistic effect in the co-pyrolysis process,and the experimental temperature for rapid co-pyrolysis was determined.Rapid co-pyrolysis of cellulose with HDPE was carried out in a tube furnace reactor.The results demonstrated that the effect of co-pyrolysis was deeper the higher the rapid pyrolysis temperature.As temperature rose,the yield of gases increased from11.1%to 42.8%and the yield of liquids decreased from 76.7%to 49.3%.The findings of the bio-oil study revealed that co-pyrolysis promoted the decomposition of oxygenates such as levoglucan,thus improving the quality of the tar.（2）The temperature rise rate is an important factor affecting the secondary reaction of pyrolysis.In order to investigate the effect of temperature rise rate on the co-pyrolysis interaction between CE and HDPE with different mixing ratios and the pyrolysis characteristics at different temperature rise rates.The experiments of slow co-pyrolysis and fast co-pyrolysis were carried out simultaneously in a tube furnace.The results showed that the slow co-pyrolysis could improve the liquid yield and reduce the gas and coke yields.The slow co-pyrolysis interaction was strongest at 1:3 of CE and HDPE.At this time,the liquid yield was 95.4%.The fast co-pyrolysis results were the opposite.The strongest fast co-pyrolysis interaction was observed at 3:1 CE and HDPE.The liquid and gaseous yields were49.3%and 42.8%,respectively.（3）ReaxFF MD simulations were used to study the reaction mechanism of co-pyrolysis of CE and HDPE.The results show that during co-pyrolysis,CE decomposes into C₆ products such as levoglucan and dehydrates to form carbonyl groups.At the same time,a large amount of OH radicals were generated and reached a peak at 9 ps and then decreased rapidly.The OH radicals are highly reactive and can cause HDPE to break and react with olefins to form alcohols,and the H radicals generated from HDPE promote the cracking of heavy oil and light oil to produce large amounts of CO and other gases,thus reducing the liquid yield and increasing the gas yield.更多还原