Effects of Metals from Flue Gas on Microalgae Biofuels and Co-products: Sustainability and Scalability

犹他州州立大学贾森·奎恩犹他州州立大学生产替代交通燃料对于满足当前的能源需求而不会导致全球气候变化至关重要。微藻被认为是一种很有前景的原料，但需要特定的资源(例如水和浓缩二氧化碳)，这些资源要么难以以高纯度和高浓度提供，要么与其他基本活动竞争，如粮食生产。已经进行了各种微藻可行性评估，这些评估假定废旧二氧化碳来源，如燃煤发电厂废气，与微藻培养无缝结合。在微藻培养阶段利用烟道气作为二氧化碳的来源，是利用微藻生产生物燃料的一种环境友好的工艺步骤。燃烧煤炭会产生一股富含二氧化碳的溪流，非常适合与微藻融合，但也含有微量的各种重金属，如砷、镉、钴、铬、铜、汞、锰、镍、铅、锑、硒、锡、碲、钛、钒和锌。在微藻培养中，烟道气体作为营养源的整合最终会将这些重金属引入到生长介质中，在那里它们可以被微藻吸收并可能被浓缩。这项研究将量化重金属的去向及其对微藻养殖的影响，以及使用烟道气作为碳源的最终产物的特征。了解重金属在微藻转化为生物燃料过程中的影响和去向将有助于更高分辨率的环境评估。本研究将探讨1)生长介质中重金属对微藻生长和脂肪含量的影响以及对生产生物柴油质量的影响；2)重金属对发酵提取脂肪的藻类生产丙酮、丁醇和乙醇的下游加工以及厌氧消化产生甲烷的影响；3)微藻对与烟气相结合的生物燃料过程的可持续性和可扩展性。完成这些任务将有助于评估废气中发现的重金属对微藻培养及其产物的影响。这项研究将调查可能发生重金属积聚的潜在过程，并量化所涉及的数量。系统模型将从实验数据中获得信息，以进行可伸缩性和环境影响评估。该项目将为微藻培养与来自工业点源二氧化碳(如燃煤电厂烟气)的环境影响提供新的见解。烟气与微藻培养相结合，不可避免地会将重金属引入到生长介质中，可以吸收和浓缩。这项研究将评估存在于微藻生长介质中的重金属的最终归宿，并调查从微藻到生物燃料过程中对生长、燃料性质和副产物的影响。从实验工作中获得的信息将被整合到一个建模工作中，以直接评估将富碳烟道气与微藻培养相结合的大规模环境影响。

CBET - 1335550Jason QuinnUtah State UniversityThe production of alternative transportation fuels is imperative to meeting current energy demands without contributing to global climate change. Microalgae are considered a promising feedstock, but require specific resources (e.g. water and concentrated carbon dioxide) that are either difficult to provide in high purity and concentration or that compete with other essential activities such as food production. A variety of microalgae feasibility assessments have been performed that assume the seamless integration of waste carbon dioxide sources, such as coal fired power plant flue gas, with microalgae cultivation. The utilization of flue gas as a source for carbon dioxide in the cultivation phase of microalgae represents an environmentally favorable process step for the production of biofuels from microalgae. The burning of coal generates a carbon dioxide rich stream ideal for integration with microalgae, but also contains trace amounts of a variety of heavy metals such as arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, nickel, lead, antimony, selenium, tin, tellurium, titanium, vanadium, and zinc. The integration of flue gases as a nutrient source in microalgae cultivation will ultimately introduce these heavy metals into the growth media where they can be absorbed and potentially concentrated by the microalgae. The fate of heavy metals and their effect on microalgal cultivation and the characteristics of end products from the use of flue gas as the carbon source will be quantified by this study. Understanding the effect and fate of heavy metals in the microalgae-to-biofuels process will enable higher resolution environmental assessments. The study will investigate 1) the effects of the presence of heavy metals in growth media on microalgae growth and lipid content and the effects on the quality of biodiesel produced, 2) the effects of heavy metals on downstream processing of the lipid extracted algae via fermentation for production of acetone, butanol and ethanol and methane production from anaerobic digestion, and 3) the sustainability and scalability of the microalgae to biofuels process integrated with flue gas. Accomplishment of these tasks will facilitate the evaluation of the effects of heavy metals found in flue gas on microalgae cultivation and resulting products. This study will investigate potential processes where heavy metal buildup could occur and quantify the amounts involved. Systems models will be informed by the experimental data for scalability and environmental impact assessments.This project will provide new insights into the environmental impacts of integrating microalgae cultivation with carbon dioxide derived from industrial point sources such as coal power plant flue gas. The integration of flue gas with microalgae cultivation will inevitably introduce heavy metals into the growth media that can be absorbed and concentrated. This study will evaluate the end fate of heavy metals present in microalgae growth media and investigate the effects on growth, fuel properties and co-products from the microalgae to biofuels process. The information learned from the experimental work will be integrated into a modeling effort to directly assess the large-scale environmental implications of integrating carbon rich flue gas with microalgae cultivation.