Mixing of Biofuels in Surface Waters

地表水中生物燃料的混合

• 批准号: 1335878
• 负责人: Aline Cotel
• 金额: $ 33万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1335878&HistoricalAwards=false
• 关键词: Mixing; Biofuels; Surface; Waters

CBET 1335878 Aline CotelUniversity of Michigan Ann ArborEthanol/gasoline blends are being promoted as "clean energy" alternatives and are viewed by many policymakers as key to reducing reliance on foreign oil and lowering emissions of greenhouse gases, thereby satisfying both the energy security and environmental agendas of the U.S. However, ethanol-based biofuels can pose a risk to the aquatic environment, as large fish kills attributable to ethanol spills have already been documented. Due to its complete miscibility in water, ethanol may become mixed in the water body in high concentrations. The physics of this mixing process are complex and appear to be influenced by the production of heat and variations in interfacial tension and viscosity. This research will elucidate the physics of mixing of biofuels in surface water by conducting experiments to measure the rate of mixing and entrainment in a multiphase system using DPIT (digital particle image thermometry) and DPIV (digital particle image velocimetry). The goal is develop a correlation between the degree of mixing and the relevant nondimensional parameters. The high concentrations of ethanol may solubilize hazardous compounds such as benzene from gasoline into the water column. Due to the high organic compound loading in the water column, pesticides historically present in sediment may desorb and be re-suspended in the water column. This study will evaluate the enhancement of desorption of organochlorine pesticides from sediment that may occur in the presence of ethanol and gasoline mixtures due to cosolvency effects as well as due to possible changes in the structure in sediment organic matter. The goal is to quantify the degree of desorption as a function of the composition of the mixtures of water, ethanol and gasoline, and the properties of the sediment.In an effort to promote ethanol/gasoline blends as an alternative fuel, potentially major negative impacts on the environment have been overlooked. The assumption is the environmental impact of biofuels on surface water is negligible as "ethanol is biodegradable." Yet, large fish kills attributable to ethanol spills have already been documented. The models used for predicting concentrations of ethanol in rivers do not reflect the actual process of mixing. This research will examine the physics of mixing of ethanol/gasoline blends in water to help develop more accurate methods for predicting ethanol concentrations in rivers. Due to their solubility in ethanol, hazardous compounds present in gasoline may be solubilized in higher concentrations in a river. With a high organic contaminant concentration in the water column, pesticides historically present in sediment may desorb and be re-suspended, thus increasing their mobility. The information provided by this study will aid in the determination of the magnitude of the environmental risk posed by spills of ethanol/gasoline blends in surface waters.

CBET 1335878 Aline CotelUniversity of Michigan Ann ArborEthanol/gasoline blends正在被推广为"清洁能源"替代品，许多政策制定者认为这是减少对外国石油依赖和降低温室气体排放的关键，从而满足美国的能源安全和环境议程。因为乙醇泄漏造成的大量鱼类死亡已经有了记录。 由于其在水中的完全溶解性，乙醇可能以高浓度混合在水体中。 该混合过程的物理学是复杂的，并且似乎受到热的产生以及界面张力和粘度的变化的影响。 本研究将阐明生物燃料在地表水中的混合物理进行实验，以测量在多相系统中使用DPIT（数字粒子图像测温）和DPIV（数字粒子图像测速）的混合和夹带率。 我们的目标是开发的混合度和相关的无量纲参数之间的相关性。 高浓度的乙醇可能会溶解有害化合物，如汽油中的苯，使其进入水柱。 由于水柱中的有机化合物含量很高，历史上存在于沉积物中的农药可能会解吸并重新悬浮在水柱中。 本研究将评估增强解吸的有机氯农药从沉积物中可能会出现在乙醇和汽油的混合物的存在下，由于共溶效应，以及由于可能的变化，在沉积物中的有机物质的结构。 目的是量化的解吸程度作为一个功能的水，乙醇和汽油的混合物的组成，和沉积物的性质，在努力促进乙醇/汽油混合物作为替代燃料，对环境的潜在重大负面影响被忽视。 假设生物燃料对地表水的环境影响可以忽略不计，因为"乙醇是可生物降解的。"然而，由于乙醇泄漏造成的大量鱼类死亡已经被记录在案。 用于预测河流中乙醇浓度的模型并不能反映实际的混合过程。 这项研究将研究乙醇/汽油混合物在水中混合的物理学，以帮助开发更准确的方法来预测河流中的乙醇浓度。 由于它们在乙醇中的溶解度，汽油中存在的有害化合物可能会在河流中以更高的浓度溶解。 由于水柱中有机污染物浓度很高，以往存在于沉积物中的农药可能会解吸并重新悬浮，从而增加其流动性。 本研究提供的信息将有助于确定乙醇/汽油混合物在地表沃茨中泄漏所造成的环境风险的程度。