CaO表面更新对微拟球藻催化热解制备生物油的影响

Production of bio-oil by catalytic pyrolysis of Nannochloropsis sp. over renewed suface CaO catalysts

分别以水合化法和热缺陷法对CaO进行表面更新，用N2物理吸附（BET）、X射线衍射（XRD）、扫描电镜（SEM）和CO2吸附技术对表面更新后的CaO进行了结构表征，并利用制备的CaO在管式炉内对微拟球藻进行了催化热解研究。结果表明：两种更新方法均能明显提高CaO的比表面积、介孔数目及孔体积。CaO的表面更新处理没有改变基本的晶相结构，仍为立方晶型。两种更新方法均能显著提高CaO的催化活性，且改善了产物油品的性能。相比较而言，水合CaO的催化脱氧性能较高，催化热解得到的生物油产率为28.65%、含氧量为4.67%、热值高达38.600 kJ·g^-1、运动黏度低（8.011 mm2·s^-1）、含水率低（2.49%），且催化热解后的生物油以C12～C17饱和直链烷烃为主，适合进一步精制为生物柴油。

The surface of calcium oxide （CaO） was renewed by using hydration-calcination and thermal calcinations methods, respectively. The structure and property of renewed CaO was characterized by BET, XRD, SEM and CO2-TPD techniques. Meanwhile, the catalytic pyrolysis ofNannochloropsis sp. was investigated in a fixed-bed reactor. It is shown that two preparation methods for CaO obviously increase the specific surface area, meso-pore numbers, and pore volume. The renewed surface CaO catalysts were of typical face-centered structure and of higher catalyst activity, and could improve bio-oil product quantity. The yield of bio-oil produced on the hydration-calcination CaO was 28.65%, which was of higher calorific value （38.600 kJ·g^-1）, lower kinetic viscosity （8.011 mm2·s^-1）, and lower moisture content （2.49%）. The main ingredients of bio-oil from catalytic pyrolysis ofNannochloropsis sp. were C12-C17 saturated normal alkanes, which are more suitable for being upgraded to bio-diesel.