Techno-economic analysis of autotrophic microalgae for fuel production
Techno-economic analysis of autotrophic microalgae for fuel production
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DOI：
10.1016/j.apenergy.2011.04.018
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发表时间：
2011-10-01
期刊：
影响因子：
11.2
通讯作者：
Pienkos, Philip T.
中科院分区：
文献类型：
--
作者：
Davis, Ryan;Aden, Andy;Pienkos, Philip T.
众所周知，微藻衍生的生物燃料有潜力为美国燃料市场做出重大贡献，这是由于藻类固有的几个独特特性。也就是说，与陆地油籽作物相比，自养微藻在将太阳能转化为生物质和油方面能够达到非常高的效率，同时在藻类种植所需的土地和水的质量方面表现出很大的灵活性。与今天的石油燃料市场相比，这些特性使得生产相当数量的藻类生物燃料成为可能，同时大大减轻了“食物与燃料”的担忧。然而，由于藻类生物燃料产业的初期阶段对工艺规模的不确定性和猜测，公众对藻类生物燃料的近期经济可行性普遍缺乏共识。目前的研究旨在建立两种微藻途径的基线经济学，方法是使用一组假设对在五年时间框架内可能实现的目标进行全面分析。具体途径包括通过开放池塘和封闭管式光生物反应器（PBR）系统进行自养生产。生产规模设定为每年1000万加仑的生藻油，随后通过加氢处理升级为“绿色柴油”混合原料。使用Aspen Plus模拟软件进行严格的质量平衡，并在单位层面上评估相关成本。在完成基本情景后，为实现10%的回报率，露天池塘的脂质生产成本为8.52美元/加仑，pbr为18.10美元/加仑。加氢处理生产柴油混合料的价格略微增加，分别达到9.84美元/加仑和20.53美元/加仑的柴油价格。如果能够确定能够在高脂含量下维持高生长速率的更好的微藻菌株，这些成本在未来有可能显著改善。鉴于很难同时最大化这两个参数，因此确定近期的研究应侧重于最大化脂质含量，因为相对于提高藻类生长速度，脂质含量具有更大的成本降低潜力。建立了额外的经济敏感性研究，以确定其他重要的成本驱动因素，并进行了资源评估比较，以评估水和CO(2)需求等参数。(C) 2011 Elsevier Ltd.版权所有。
It is well-established that microalgal-derived biofuels have the potential to make a significant contribution to the US fuel market, due to several unique characteristics inherent to algae. Namely, autotrophic microalgae are capable of achieving very high efficiencies in converting solar energy into biomass and oil relative to terrestrial oilseed crops, while at the same time exhibiting great flexibility in the quality of land and water required for algal cultivation. These characteristics allow for the possibility to produce appreciable amounts of algal biofuels relative to today's petroleum fuel market, while greatly mitigating "food-versus-fuel" concerns. However, there is a wide lack of public agreement on the near-term economic viability of algal biofuels, due to uncertainties and speculation on process scale-up associated with the nascent stage of the algal biofuel industry.The present study aims to establish baseline economics for two microalgae pathways, by performing a comprehensive analysis using a set of assumptions for what can plausibly be achieved within a five-year timeframe. Specific pathways include autotrophic production via both open pond and closed tubular photobioreactor (PBR) systems. The production scales were set at 10 million gallons per year of raw algal oil, subsequently upgraded to a "green diesel" blend stock via hydrotreating. Rigorous mass balances were performed using Aspen Plus simulation software, and associated costs were evaluated on a unit-level basis. Upon completing the base case scenarios, the cost of lipid production to achieve a 10% return was determined to be $8.52/gal for open ponds and $18.10/gal for PBRs. Hydrotreating to produce a diesel blend stock added onto this marginally, bringing the totals to $9.84/gal and $20.53/gal of diesel, for the respective cases. These costs have potential for significant improvement in the future if better microalgal strains can be identified that would be capable of sustaining high growth rates at high lipid content. Given that it is difficult to maximize both of these parameters simultaneously, it was determined that the near-term research should focus on maximizing lipid content as it offers more substantial cost reduction potential relative to an improved algae growth rate. Additional economic sensitivity studies were established to identify other important cost drivers, and a resource assessment comparison was made to evaluate parameters such as water and CO(2) requirements. (C) 2011 Elsevier Ltd. All rights reserved.