Anaerobic digestion of microalgae:potential, bottleneck and solution

doi:10.16085/j.issn.1000-6613.2018-0567

Abstract

Abstract: Anaerobic digestion of microalgae for methane productions is an important way to realize microalgal biofuels production, but there are problems such as incomplete digestion and low methane conversion ratio. By calculating the theoretical methane potential, it is revealed that all types of microalgal biomass have great methane production potential, which is generally higher than typical biomass, such as activated sludge, and is equivalent to energy-rich kitchen waste. However, the methane conversion ratio of most microalgal biomass is below 50%, making their actual methane yield even lower than that of activated sludge. Difficulty in breaking the cell wall and low C/N ratio of microalgal biomass are the main reasons for the low methane conversion ratio. Various methods for enhancing anaerobic digestion of microalgae are summarized from aspects of pretreatment and co-digestion. Among them, low-temperature thermal treatment is currently the most economically and technically feasible pretreatment method. Co-digestion with carbon-rich substrates is an effective way to solve the low C/N ratio problem, but its effect appears only at high organic loading rates. Excess sludge alone is not a suitable co-digestion substrative for microalgae. Finally, it is suggested to further explore the synergistic effect of pretreatment and co-digestion and to focus on the practical performance of anaerobic digestion of microalgae under continuous operating conditions.

Key words: microalgae, anaerobic digestion, pretreatment, co-digestion

摘要： 厌氧消化产甲烷是实现微藻生物质能生产的重要方式，但存在消化不彻底、甲烷转化率偏低等问题。本文从理论产甲烷潜力入手，揭示了各类微藻生物质均具有良好的产甲烷潜力，普遍高于活性污泥等典型生物质，与富含能量的厨余垃圾相当。然而大部分微藻生物质的甲烷转化率都低于50%，使其实际甲烷产率处于甚至低于活性污泥的水平。微藻破壁困难和C/N比低是其甲烷转化率低的主要原因。文章从预处理和共消化两方面总结归纳了强化微藻厌氧消化的各种方法。其中低温热处理是目前最具经济技术可行性的预处理方法。与高含碳基质共消化是解决C/N比低的有效手段，但其作用需在高有机负荷下才能显现。剩余污泥不宜单独作为微藻的共消化基质。最后建议进一步探究预处理与共消化的协同作用以及重点考察连续运行工况下微藻厌氧消化的实际效果。

关键词: 微藻, 厌氧消化, 预处理, 共消化

CLC Number:

X703

WU Yuhan, ZHANG Xiaoran, HU Yuansheng. Anaerobic digestion of microalgae:potential, bottleneck and solution[J]. Chemical Industry and Engineering Progress, 2018, 37(11): 4237-4249.

吴宇涵, 张晓然, 胡沅胜. 微藻厌氧消化产甲烷：潜能、瓶颈及解决方案[J]. 化工进展, 2018, 37(11): 4237-4249.

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