Liquid Biofuels: Fluid Properties to Optimize Feedstock Selection, Processing, Refining/Blending, Storage/Transportation, and Combustion

As the availability of petroleum-based liquid fuels is becoming increasingly problematic, alternative renewable biofuels attract growing research and development (R&D) and industry interest. The focus is to produce fuels with desired properties in both technically and economically attractive ways to support sustainability and protect the environment. While abundant, the variety of biomass feedstocks brings a great deal of incompatibility of various biofuels and the combustion engines. A consistent theme is that better knowledge of fuel properties would lead to better designs and shorter development times of everything from fuel production facilities to emission control systems. Thermophysical properties of biofuels are required to efficiently design the processes involved in their production, distribution, and utilization. These properties are also needed to develop and validate physicochemical models, the tools employed in process design, product development, or academic research. To date, the connection between the expertise in fluid properties and an integrating knowledge of where and how these properties are employed has not been adequately developed. Accordingly, the main goal of this review is to unite and set out the potential for synergy between all of the essential steps of fuel production and applications (from feedstock selection to the end use) with the properties of the fuel at each step. An integrating approach on a broad scale is helpful for the increasing number of fuel researchers, process engineers, entrepreneurs, and end users. This review discusses the main driving forces that are likely to encourage further development and move the emerging biofuel technologies from promising ideas to competitive solutions.