低脂高蛋白藻水热液化过程关键元素迁移与成油机制

Algal hydrothermal liquefaction (HTL) is a new research trend of algal bioenergy due to its advantages of no lipid-content restriction, using wet feedstocks and rapid reaction. Low-lipid high-protein algae are widely distributed in nature with high growth rate and biomass production. It is straightforward to convert these algae into biocrude oil through via HTL, having environmental and energy benefits. Due to the unclear mechanism for oil production and key elements migration, this project firstly focuses on the conversion pathway and dynamics of model proteins during HTL. The interaction transformation of proteins with other components is also investigated. Model low-lipid high-protein algae are then selected and the mass and energy balances during HTL are systematically studied through the analysis of morphology, structure, component and functional group. Furthermore, the key control factors and core chemical reactions are proposed based on the study of protein based HTL. The mechanism of biocrude production from low-lipid high-protein algae during HTL is finally interpreted by probing the footprint and morphological transformation of key elements via element tracer and NMR. This project will establish the scientific foundation for the biocrude oil production from low-lipid high-protein algae and its application.

藻类生物质水热液化直接制备生物原油因其具有不受含脂量限制、原料无需干燥、反应快等优点，是近年来藻基能源转化的一个新方向。低脂高蛋白藻广泛存在于富营养化湖泊、海岸等区域，速生高产，将其水热转化具有重要的环境价值和能源收益。针对该类藻中蛋白含量高引起的成油机制不清、关键元素迁移规律不明等问题，本项目首先研究以蛋白质为核心的模型化合物水热液化与成油过程，揭示蛋白质成油的转化路径及与其他组分(灰分、脂肪、糖等)的交互影响规律；在此基础上选取模式低脂高蛋白藻，通过形态、结构、组分与基团分析，研究模式藻解聚和转化过程的质能平衡，在阐明蛋白质成油反应路径的基础上提出低脂高蛋白藻水热液化的关键节点与主体反应。采用元素分析、NMR等方法研究藻体中碳、氮、氢等关键元素在转化过程中足迹与时空迁移规律，阐释低脂高蛋白藻水热液化成油机制。本项目将为我国低脂高蛋白藻的水热液化成油技术及应用奠定科学基础。

本项目是主要探索了高灰分滇池藻与高脂/高蛋白混合液化的研究；低脂高蛋白与高脂低蛋白微藻水热液化产油以及关键元素迁移研，研究有针对性的选取低灰分的高脂藻（Chlorella sp.，简称 Y）、高蛋白质藻（Spirulina sp.，简称 G） 的两种典型微藻进行混合液化，通过协同作用来提升水热 液化的产油率和液化率。滇池藻与高脂藻的混合液化有利协同产油；而与高蛋白质藻混合液化后更 有利于协同降解。高蛋白质藻与滇池藻的混合液化可以获得一定的产油协同效率更能得到极大的液化协同效应，且相对高脂藻 的混合液化，温度对协同效应影响不大。鸡粪沼液基小球藻藻与纯培养藻水热液化对比以及放大效应研究表明 500 mL放大实验后生物原油产率（33.20 ± 1.13%dw）高于100 mL反应釜（28.79 ± 0.86%dw）. UF小球藻HTL放大实验能保持产油率不降低，这表明该优化工艺具有较好的重复性。微藻水质预处理及微藻培养研究发现批式反应器中添加不同的吸附剂联合菌藻共生系统处理HTL废水的污染物可以提高去除效果。本项目通过元素分析研究关键元素在原料与产物中的迁移转化，揭示了藻类水热液化成油作用机理，为提高转化率与油品，实现水热液化副产物的资源化利用奠定基础。