(80g) Production of Biofuel From Biomass Via Fast Pyrolysis and Hydrotreatment Processes

Depletion of fossil oil resources, global climate change and national security concerns have put the development of alternative energy to the central stage. Compared to the other alternative energy choices, the production of energy and chemicals from biorenewable resources, such as biomass, has attracted increasing research interests in recent years due to the vast potential availability of biomass materials and the availability of existing technologies that potentially enable the production of energy and chemicals in commercial scales in shorter time period in the future. Center for Sustainable Environmental Technologies (CSET) is a research center at Iowa State University (ISU) that has been working on promoting, developing and demonstrating the thermochemical technologies such as gasification and fast pyrolysis, and catalytic upgrading processes, for the production of fuels, chemicals, and energy from biomass. This presentation is to report the current work at CSET on a process of production of liquid fuels from biomass by using a combination of fast pyrolysis and catalytic upgrading technologies. In the process, cellulosic biomass is first fast-pyrolyzed to produce a liquid, typically called fast pyrolytic oil or bio-oil, as the primary product. Resembling petroleum crude oil in appearance, bio-oil is highly viscous reactive concoction of organic compounds, derived from biomass components (cellulose, hemicelluloses, and lignin) and is not only heterogeneous but also thermally and chemically unstable. Like petroleum crude, bio-oil needs to be further processed in order to be used for final applications (e.g. transportation fuels), however the chemical properties of bio-oil makes it more challenging to process, compared to the fossil-derived oil. The elemental composition of bio-oil contains significant amounts of oxygen as high as 35-40% with 54-58% carbon and about 5.5-7% hydrogen, which make bio-oil reactive and has lower energy content compared to petroleum-derived oil. Moreover bio-oil is represented by approximately more than 300 compounds of various classes. Many bio-oil components are highly polar compounds (such as acetic acid, furfural and hydroxyacetaldehyde). The presence of phenols, furans and carbohydrates (sugars) are also highly pronounced. The high oxygen content of bio-oil may be reduced by using the hydrodeoxygenation process, typically used in petroleum refineries; however not without significant modification of the process. The catalytic upgrading of bio-oil requires a multi-dimensional approach which involves both chemistry (including catalyst synthesis) and engineering approaches. At ISU, one engineering approach has been developed by the way of producing bio-oil, in which bio-oil produced from fast pyrolysis process is collected in fractions. This approach enables bio-oil components that cause bio-oil reactivity and instability, such as organic acids and water, to be separated out from the primary bio-oil components to be catalytically upgraded. At present, the catalytic upgrading work by using selected bio-oil fractions produced at Iowa State Unviersity is being performed . It is reported that the current work on hydrodeoxygenation of bio-oil focuses on the following four main steps. (i) Complete characterization of bio-oil employing complementary techniques such as GC-MS, HPLC and TGA. (ii) Synthesis and characterization of novel catalysts employing XRD, TGA, Chemisorption, BET and TEM. (iii) Study of model compounds such as acetic acid, furfural and phenol which are representative of bio-oil functionality. (iv) Fractionation of bio-oil and comparing each fraction and as a whole in evaluating the efficiency of the hydrodeoxygenation.