热解温度对微藻基生物质热解焦性质的影响

Pyrolysis temperature impact on the microalgal biomass char characteristics

利用立式加热炉在400~800℃下进行微藻及其脱脂藻渣热解试验,探究热解温度对微藻基生物质热解焦性质的影响规律。利用扫描电镜(SEM)、激光粒度仪、CHNS/O元素分析仪、X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)和电感耦合等离子体光谱仪(ICP)等对不同温度下的热解焦进行理化性质分析。结果表明:随着热解温度的升高,微藻和藻渣的产焦率呈下降趋势,热解焦的C/H和C/O随之增大,颗粒平均粒径先减小后增大,比表面积先增大后减小。温度升高有利于热解焦碳结构和石墨结构的形成,温度过高则会发生烧结现象,孔隙结构也随之变差。微藻和藻渣热解焦中重金属元素浓度均处于洁净水平,热解过程可以有效降低微藻基生物质中重金属的潜在生态威胁。

The pyrolysis experiments of microalgal biomass at 400-800℃were conducted in a vertical tube furnace to study the influence of temperature on the pyrolysis char.Besides,the scanning electron microscope(SEM),laser particle size analyzer,CHNS/O elemental analyzer,X-ray fluorescence spectrometer(XRF),X-ray diffractometer(XRD)and inductively coupled plasma mass spectrometry(ICP)were used to examine the physical and chemical characteristics of the pyrolysis char under different temperatures.Results show that with the increase of pyrolysis temperature,char production rate of microalgae and residue reduced,C/H and C/O of pyrolysis char become bigger,the average particle diameter decreases firstly and then increases,and the specific surface area rises firstly and then decreases.The promotion of temperature is beneficial to carbon and graphite structure formation of pyrolytic char,while the sintering will occur,and the void structure can be damaged when the temperature is too high.Finally,the concentration of heavy metal elements in pyrolysis char of microalgae and the residue is at clean level.Pyrolysis process can reduce the potential ecological threat of pyrolysis of heavy metals effectively.