Hydrothermal processing of microalgae using alkali and organic acids
Hydrothermal processing of microalgae using alkali and organic acids
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DOI：
10.1016/j.fuel.2010.01.025
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发表时间：
2010-09-01
期刊：
影响因子：
7.4
通讯作者：
Jones, J. M.
中科院分区：
文献类型：
--
作者：
Ross, A. B.;Biller, P.;Jones, J. M.
微藻等水生生物因其生长速度快、封存CO(2) 的能力以及产生脂质的潜力而被认为是第三代生物燃料的潜在来源。水热液化转化非常适合微藻等高水分含量原料，并且涉及在存在或不存在催化剂的情况下在热压缩水中处理生物质。本研究旨在探讨从含有低脂质含量的微藻和蓝藻（包括普通小球藻和螺旋藻）生产高质量、低分子量生物原油的条件。在 300 摄氏度和 350 摄氏度的高压间歇反应器中进行了液化实验。研究了温度和催化剂类型等工艺变量的影响。使用的催化剂包括碱、氢氧化钾和碳酸钠以及有机酸、乙酸和甲酸。液化产量已确定，生物原油的 CHNOS 含量和热值已进行分析。通过 GC/MS 分析生物原油的成分，并通过热重分析 (TGA) 估算其沸点范围。通过离子交换色谱法分析水相中的典型阳离子和阴离子以及总有机碳 (TOC)。使用有机酸催化剂，生物原油的产量更高，沸点更低，流动性能得到改善。生物原油的碳含量通常为 70-75%，氧含量为 10-16%。生物原油中的氮含量通常为 4% 至 6%。较高热值 (HHV) 范围为 33.4 至 39.9 MJ kg (1)。 GC/MS 分析表明，生物原油含有芳香烃、氮杂环以及长链脂肪酸和醇。氮平衡表明大部分燃料氮（高达 50%）以铵的形式转移到水相中。其余部分分布在生物原油和气相之间，气相含有 HCN、NH(3) 和 N(2)O，具体取决于催化剂条件。有机酸的添加导致水相中氮的减少以及气相中NH(3)和HCN的相应增加。有机酸的添加对所生产的生物原油的收率和沸点分布具有有益的影响。 (C) 2010 Elsevier Ltd. 保留所有权利。
Aquatic organisms such as microalgae have been identified as a potential source of third generation biofuels due to their fast growth rate, ability to sequester CO(2) and their potential for producing lipids. Conversion by hydrothermal liquefaction is ideally suited to high moisture content feedstocks such as microalgae and involves the processing of biomass in hot compressed water with or without the presence of a catalyst. This study aims to investigate the conditions for producing high quality, low molecular weight bio-crude from microalgae and cyanobacteria containing low lipid contents including Chlorella vulgaris and Spirulina. Liquefaction experiments have been performed in a high pressure batch reactor at 300 degrees C and 350 degrees C. The influence of process variables such as temperature and catalyst type has been studied. Catalysts employed include the alkali, potassium hydroxide and sodium carbonate and the organic acids, acetic acid and formic acid. Liquefaction yields have been determined and the bio-crude has been analysed for CHNOS content and calorific value. The bio-crude has been analysed by GC/MS to examine composition and thermal gravimetric analysis (TGA) to estimate its boiling point range. The aqueous fraction has been analysed for typical cations and anions by ion exchange chromatography and for total organic carbon (TOC). The yields of bio-crude are higher using an organic acid catalyst, have a lower boiling point and improved flow properties. The bio-crude contains a carbon content of typically 70-75% and an oxygen content of 10-16%. The nitrogen content in the bio-crude typically ranges from 4% to 6%. The higher heating values (HHV) range from 33.4 to 39.9 MJ kg (1). Analysis by GC/MS indicates that the bio-crude contains aromatic hydrocarbons, nitrogen heterocycles and long chain fatty acids and alcohols. A nitrogen balance indicates that a large proportion of the fuel nitrogen (up to 50%) is transferred to the aqueous phase in the form of ammonium. The remainder is distributed between the bio-crude and the gaseous phase the latter containing HCN, NH(3) and N(2)O depending upon catalyst conditions. The addition of organic acids results in a reduction of nitrogen in the aqueous phase and a corresponding increase of NH(3) and HCN in the gas phase. The addition of organic acids has a beneficial effect on the yield and boiling point distribution of the bio-crude produced. (C) 2010 Elsevier Ltd. All rights reserved.