Background Energy demand by mankind has become one of the most important aspects of our society. A promising technology that seeks to provide part of the energy demand and to obtain high-value products is the thermochemical conversion of microalgae biomass. Inorganic species presented in microalgae biomass may act as catalysts for thermochemical reactions and are responsible for notorious ash-related issues during thermochemical decomposition. Results In this study, the freeze-dried biomass of Scenedesmus sp. was used to evaluate the lipid extraction methodology regarding a sonication bath as pretreatment technique for cell disruption followed by vortex mixing and n-hexane as solvent. It is also presented the lipid and amino acid profiles for Scenedesmus sp. The freeze-dried biomass was pyrolysed through a TGA (thermogravimetric analysis), with heating rates of 20 °C/min, from 100 to 650 °C. The ash and sulfated ash contents were accurately determined by combustion of biomass in a muffle furnace. The element component of ashes of the freeze-dried, defatted, pyrolysed and sulfated biomasses was determined by means of scanning electron microscope (SEM) fitted with energy dispersive spectroscopy (EDS). The lipid content obtained for Scenedesmus sp. dry biomass was 16.72% (± 0.03). The content of the sulfated ash obtained was 17.81 ± 0.15%. The SEM-EDS technique identified different mineral compounds in ashes, allowing to quantify Mg, P, S, K, Ca, Fe, Co and Br, as well as oxides. Conclusion The results suggest a possible strategy to evaluate in a semi-quantitative manner the ash composition of freeze-dryed, defatted, sulfated and pyrolysed biomass of Scenedesmus sp. and its feasibility in using Scenedesmus sp. biomass in different thermochemical conversion strategies to achieve processes with positive energy ratio, representing potential use both environmental and energetically.

中文翻译：

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半定量测定栅藻冻干、脱脂、硫酸化和热解生物质的灰分含量。

背景人类对能源的需求已成为我们社会最重要的方面之一。旨在提供部分能源需求并获得高价值产品的有前途的技术是微藻生物质的热化学转化。微藻生物质中存在的无机物种可能充当热化学反应的催化剂，并导致热化学分解过程中臭名昭著的灰分相关问题。结果在本研究中，栅藻的冻干生物量。用于评估脂质提取方法，将超声浴作为细胞破碎的预处理技术，然后涡旋混合和正己烷作为溶剂。它还提供了栅藻属的脂质和氨基酸谱。冷冻干燥的生物质通过 TGA（热重分析）进行热解，加热速率为 20 °C/min，从 100 到 650 °C。通过在马弗炉中燃烧生物质来准确测定灰分和硫酸化灰分含量。采用配备能谱仪(EDS)的扫描电子显微镜(SEM)测定冻干、脱脂、热​​解和硫酸化生物质灰分的元素成分。栅藻的脂质含量。干生物量为 16.72% (± 0.03)。得到的硫酸化灰分含量为 17.81 ± 0.15%。SEM-EDS 技术可识别灰烬中的不同矿物化合物，从而可以量化 Mg、P、S、K、Ca、Fe、Co 和 Br 以及氧化物。结论 该结果提出了一种可能的策略来以半定量的方式评估栅藻属的冷冻干燥、脱脂、硫酸化和热解的生物质的灰分组成。及其在使用Scenedesmus sp的可行性。生物质在不同的热化学转化策略中实现具有正能量比的过程，代表了环境和能源的潜在用途。