Biorefineries

Relatively recent interest in biofuels is rooted in the growing concern over rising global greenhouse gas emissions, energy independence, and support of agricultural industries. Although biofuels are still a small segment of the fuels industry, technologies that convert biomass into biofuels are widely being developed for industrial-scale application, and are expected to play an increasingly important role going forward. This chapter gives a broad overview of the major biofuels conversion pathways including fermentation both from plant sugars and lignocellulose-derived sugars, biodiesel, hydroprocessing of vegetable and animal oils, gasification, pyrolysis, and liquefaction. Special attention is given to hydrotreating and hydroisomerization of vegetable and animal oils due to its prevalence in industry, and its strong relationship with similar petroleum hydroprocessing covered in other chapters in this handbook. Life cycle analysis, measurement of biologically-derived carbon, and issues of integration of biofuels into fuel supplies that are still largely petroleum-based are also discussed.