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研究了固定床上生物质热解过程中碱及碱土金属的迁徙规律,并结合扫描电镜–能谱分析对热解焦颗粒表面的相关无机元素富集状态进行了探索。研究发现在低温下钾的析出量较少,高温时则析出量迅速增加。钾的析出量与焦炭的堆积状态和生物质中的硅含量有较大关系。由于与焦炭的结合能力较弱,钠的析出比例较大。钙、镁在较低的热解温度下主要为有机钙、镁组分的分解,而在高温下则主要以较为稳定的形式存在于焦炭中。扫描电镜–能谱分析研究结果表明高温下生物质焦的形态稳定性与硅含量有关,钾元素的富集量与Cl存在明显的相关性。在焦炭的外表面,钾元素主要以硅酸盐形式存在,在焦炭的内表面,则主要以氯化钾形式存在。
The migration regularity of alkali and alkaline earth metals during the pyrolysis of biomass on fixed bed was studied, and the relevant inorganic element enrichment state on pyrolysis coke particles was explored by SEM-EDS. The study found that the precipitation of potassium at low temperatures less, the rapid increase in precipitation at high temperatures. The amount of potassium precipitated has a great relationship with the accumulation of coke and the silicon content in biomass. Due to the weak binding capacity with coke, sodium precipitation rate is larger. Calcium and magnesium are mainly decomposed of organic calcium and magnesium components at lower pyrolysis temperature, while coke is mainly present in a relatively stable form at high temperature. The results of SEM and EDS show that the morphological stability of biomass coke at high temperature is related to the silicon content, and the enrichment of potassium is obviously related to Cl. On the outer surface of the coke, the potassium element mainly exists in the form of a silicate, and on the inner surface of the coke, it is mainly in the form of potassium chloride.