典型海鲜废弃物热解特性及动力学研究

Pyrolysis characteristics and kinetics of typical seafood wastes

本研究采用热重分析手段,对鱼骨、蟹壳、虾壳三种典型海鲜废弃物的热解特性进行分析,研究不同升温速率(20、40、60℃/min)条件下热解过程的特征参数,分析原料成分组成对于海鲜废弃物热解特性的影响。基于热解特性参数对热解过程进行动力学分析,结合表观动力学参数并在对比多种机理模型的拟合效果基础上,确定了较为适宜的海鲜废弃物热解过程机理模型。结果表明,海鲜废弃物热解过程与其成分组成具有密切关联,TG-DTG曲线对比分析发现,有机质和无机盐含量是影响热解过程的重要因素。随着升温速率的提高,三种海鲜废弃物的热解特性参数具有一致的增长趋势。动力学研究发现,鱼骨主要热解过程符合一级化学反应机理,而蟹壳和虾壳在有机物分解阶段可由一段1.5级化学反应过程描述,分析认为,反应级数的差别与与海鲜废弃物中几丁质含量有关。表观活化能Ea随着升温速率的提高而增大,而活化能增量?Eα逐渐变小,可以推测采用不低于40℃/min的升温速率不会导致三种海鲜废弃物热解过程难度的增大并更具经济性。研究结果为海鲜废弃物热解处理技术的开发提供了基础过程特性数据。

Pyrolysis is an important technology for the harmless reduction of food waste. In this paper,thermogravimetric analysis was used to analyze the pyrolysis characteristics of three typical seafood wastes, namely fish bones, crab shells, and shrimp shells, and to study the characteristic parameters of the pyrolysis process at different heating rates(20, 40, and 60 ℃/min), to analyze the effect of different components on the pyrolysis characteristics of seafood waste. The kinetic analysis of the pyrolysis process was carried out based on the pyrolysis characteristic parameters, combined with the apparent kinetic parameters and the fitting effects of various mechanism models were compared, and a more suitable mechanism model for the pyrolysis process of seafood waste was determined. The results showed that the pyrolysis processes of the three seafood wastes were closely related to their components, and the comparative analysis of TG-DTG curves found that the content of organic matter and inorganic salts were important factors affecting the pyrolysis process. The pyrolysis characteristic parameters of the three seafood wastes showed a consistent increasing trend with the increase of the heating rate.The main pyrolysis process of fish bones conforms to the first-order chemical reaction mechanism, and the organic matter decomposition stage of crab shells and shrimp shells can be described by a 1.5-order chemical reaction process. The large amount of chitin in shrimp shells and crab shells is the main reason for the difference in the order of chemical reactions. The activation energy increases with the increase of the heating rate, while the increment of the activation energy gradually decreases. It could be presumed that the adoption of larger heating rates over40 ℃/min would probably not arise more severe pyrolysis condition, which would be more economical from technical view. The results achieved in this paper may provide some fundamentals for competitive technology development for seafood wastes pyrolysis and carbonization.