中文摘要：

采用动力学分析方法对三种海藻（龙须菜、角叉菜和马尾藻）进行了热解和动力学分析。结果表明，角叉菜热稳定性最低，龙须菜和马尾藻的热稳定性相近；与马尾松等典型陆地高等植物相比，海藻的热稳定性都较低。采用Popescu法计算表明，Avrami-Erofeev方程可以用来描述三种海藻的主要挥发分脱除过程。在三种海藻中，角叉菜的平均活化能最低，这也表明其热稳定性最低。与马尾松等陆高等植物相比，海藻热解发生在较低的温区，且主要表现为放热效应，而马尾松等陆地高等植物热解发生在较高的温区，存在明显的吸热效应。

英文摘要：

Seaweed is an abundant and multi-purpose biological resource in the ocean. Developing new seaweed bio-oil by thermolysis from certain fast-growing seaweed species or the residues from seaweed-process industry may lead to opening new fields of utilizing the weeds. Thermal analysis on three seaweed species （Gracilaria lemaneiformis, Chondrus ocellatus and Sargassum natans ） for the purpose was performed. Three characteristic stages on TG-DTG-DSC （thermogravimetry-derivative thermogravimetry-differential scanning calorimetry） profiles have been recognized. The first was a slow mass losing stage before 200℃ reflecting easy removal of thermolysis parts, such as water. The second stage was a fast mass losing between 200-400℃ （ for G. lemaneiformis） , 180-210℃ （ for C. oceUatus） and 195-350℃ （ for S. natans） indicating the depolymerization, fracturing and volatilization of macromolecules of the seaweeds and formation of semi-coke. The last stage was a slow mass losing corresponding to the semi-coke volatilization. Different temperature ranges of the second stage showed difference in thermal stability for three species：low for C. oceUatus and a little higher for G. lemaneiformis and S. natans. Compared to typical land plants such as Pinus tabulaeformis （ Chinese Red Pine）, seaweed is much lower in thermal stability. Avrami-Erofeev equation was used to describe major devolatilization of the three seaweed species, which indicating that thermolysis mechanism is a random nucleation and post nuclei growth. Results of activation energy calculated by Popescu method and Ozwa-Flynn-Wall method agree well with each other and the energy increases as conversion rate increases, which indicates that those less thermally stable components volatile first. Among the three species, C. oceUatus has the lowest activation energy in average and also the lowest thermal stability. Unlike the Chinese red pine, the thermolysis of seaweed takes place at lower temperature being mainly exothermic, whereas