海藻生物质灰熔融特性分析

Fusing Characteristic Analysis on Seaweed Biomass Ash

通过灰成分分析、X射线衍射方法、热显微镜观察及TG-DTG-DTA联用试验,对3种海洋生物质——海藻的灰熔融过程进行了研究。研究表明:海藻灰渣中都有大量碱金属氯化物结晶相,随着灰化温度的升高,结晶相强度减弱,发生了碱金属的蒸发,因而海藻热化学转化能源利用时必须考虑碱金属的蒸发问题。海藻的灰熔点较低,我国国家标准(GB)与美国ASTM标准规定的灰化温度都不适合海藻类生物质,同时江蓠与马尾藻在较高灰化温度下,生成了较多的高熔点物,影响了灰熔点的判断。低温(530℃)下制得灰样的灰熔点更具有参考性。此外,各海藻结渣特性与灰熔融特性相差较大,江蓠与马尾藻灰的变形温度与半球温度相差很大,条浒苔则相差很小。

The ash fusing characteristics on three sorts of seaweed （a kind of marine biomass） were studied by using ash composition analysis, X-ray diffraction, thermal microscope, and simultaneous thermogravimetry/differential thermal analysis, It was found that there are lots of alkali chlorides in all seaweed ash samples. XRD analysis shows that the crystalline phase intensities of alkali chlorides reduce with the ashing temperature increasing, due to the evaporization of alkali chlorides, So, the evaporization of alkali chlorides in seaweed biomass must be considered during the thermal conversion. The low ash fusion temperatures make the ashing temperatures of seaweed biomass not be in the limit of temperature recommended by both GB and ASTM standard. At a high ashing temperature, Gracilaria cacalia and Sargassum natans will generate some high-melting matters which influence the identification of the ash fusion points. So it is more exact and referenced that the seaweed biomasses were ashcd at low temperature （such as 530℃ ）. Besides, the sintering characteristics and fusing characteristics of each sample are quite different. Gracilaria cacalia and Sargassum natans show a great range from the ash deformation temperature to hemisphere clathrata reveals a small deformation temperature and temperature, and Enteromorpha temperature difference between hemisphere temperature.