Key Laboratory of Agricultural Green and Low-carbon for North China Plain, Ministry of Agriculture and Rural Affairs, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Biorefining Research Institute (BRI) and Department of Chemical Engineering, Lakehead University, Thunder Bay, ON P7B 5E1, Canada.
Sci Total Environ. 2023 Nov 1;897:165443. doi: 10.1016/j.scitotenv.2023.165443. Epub 2023 Jul 12.
Investigation on the distribution and mechanism of co-pyrolysis products is vital to the directional control and high-value utilization of agriculture solid wastes. Co-pyrolysis, devolatilization, kinetics characteristics, and evolution paths of corn stalk (CS) and low-density-polyethylene (LDPE) were investigated via thermogravimetric experiments. The co-pyrolysis behaviors could be separated into two stages: firstly, the degradation of CS (150- 400 °C); secondly, the degradation of CS (400- 550 °C). The devolatilization index (DI) increased with the addition of LDPE. Furthermore, a combination of devolatilization chemical analysis with product analysis to analyze the intrinsic mechanism during co-pyrolysis. The results indicated that the yield of alkanes and olefin in gas products increased with the addition of LDPE. Additionally, LDPE pyrolysis maybe abstract hydrogen from CS pyrolysis and evolved into hydrogen, methane, and ethylene. Further, the co-pyrolysis kinetic parameters were computed by using model-free isoconversion methods, which showed promotion of CS pyrolysis and the reduced activation energy. All the activation energy were declined, which indicated a "bidirectional positive effect" during co-pyrolysis. The mean activation energy of P-cellulose (P-CE), P-hemicellulose (P-HM), P-lignin (P-LG), and LDPE decreased by 23.49 %, 12.89 %, 15.36 %, and 27.82 %, respectively. This study further proves the hydrogen donor transfer pathway in the co-pyrolysis process of CS and LDPE, providing theoretical support for the resource utilization of agricultural solid waste.
研究共热解产物的分布和机制对于农业固体废物的定向控制和高值化利用至关重要。通过热重实验研究了玉米秸秆（CS）和低密度聚乙烯（LDPE）的共热解、挥发分、动力学特性和演化路径。共热解行为可分为两个阶段：首先，CS（150-400°C）的降解；其次，CS（400-550°C）的降解。挥发分指数（DI）随 LDPE 的加入而增加。此外，采用挥发分化学分析与产物分析相结合的方法，分析共热解过程中的内在机制。结果表明，随着 LDPE 的加入，气体产物中烷烃和烯烃的产率增加。此外，LDPE 热解可能从 CS 热解中提取氢，并演变成氢、甲烷和乙烯。进一步，采用无模型等转化率法计算共热解动力学参数，结果表明 CS 热解得到促进，活化能降低。所有的活化能都降低了，这表明共热解过程中存在“双向正效应”。P-纤维素（P-CE）、P-半纤维素（P-HM）、P-木质素（P-LG）和 LDPE 的平均活化能分别降低了 23.49%、12.89%、15.36%和 27.82%。本研究进一步证明了 CS 和 LDPE 共热解过程中的氢供体转移途径，为农业固体废物的资源化利用提供了理论支持。
