Category Archives: Switchgrass

Improvements in Other Growth Aspects and Plant Protection

Improvements in other aspects of the biology of switchgrass to enable it to grow effectively in more places, including current marginal lands, while utilizing even fewer inputs, will be important to meet lignocellulosic biofuel mandates. In many of these cases, the likely candidate traits for improvement are already noteworthy in switchgrass, many of them are correlated with invasiveness (Raghu et […]

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Importance of Pretreatment

Most biofuel processes currently under development require pretreatment followed by hydrolysis to produce monomeric sugars. The goal of any pretreatment is to separate the polysaccharide matrix of cellulose and hemicellulose from lignin and to loosen the structure enabling sites for chemical or enzymatic catalysis. The polysaccharide matrix may be hydrolyzed using chemical routes (such as acid hydrolysis) or by biological […]

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Future Directions and Challenges

As users decide on which model is appropriate for their purposes, they will need to consider the level confidence in the inputs required and the appropriate level of model complexity to accomplish their goals. Process — based simulation models are split into those comprised of: 1) detailed leaf photosynthesis components that are integrated up to the leaf canopy level or […]

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Tar, NH3 and H2S

Difficulty in effective removal of syngas tars continues to be one of the biggest barriers to commercialization of gasification-based technologies for power, fuels and chemicals production. Tar is a mixture of condensable organic compound resulted from thermal degradation of biomass and is composed of mostly oxygenated aromatic hydrocarbons (Abu El-Rub, Bramer and Brem 2004). Benzene is generally not considered a […]

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Air Sparging and Agitation

Filamentous growth morphology of T. reesei results in a viscous broth rheology that affects oxygen mass transfer rate and changes the broth from a Newtonian mixture to a non-Newtonian mixture over periods of cellulolytic enzyme production. With increasing viscosity, power input requirements increase to achieve the same level of mixing. The increase in the viscosity increases the bubble size and […]

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Conclusion and Discussion

The purpose of this chapter is to identify practical issues related to the economics of developing switchgrass as a dedicated energy crop and to provide estimates of the price for delivered switchgrass biomass that would be required to compensate for the cost of inputs used to produce and deliver it to a biorefinery. As noted in the introduction, the potential […]

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Hydrodeoxygenation

Removal of oxygen from bio-oil through the addition of hydrogen is called hydrodeoxygenation (or hydrotreating and hydrogenation). Oxygen is removed in the form of water (H2O). This process takes place at temperatures of 300-400°C and pressures of 80-300 bars. The catalysts used for the dehydrogenation are Co-Mo, Ni-Mo, and their sulfides or oxides or loaded on Al2O3 (Zhang et al. […]

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Switchgrass Biology

Switchgrass has substantial variation in many phenotypic and phenological traits that allow it to be adapted to a large portion of the U. S. (Casler et al. 2004; Casler et al. 2007). There are two distinct groups of switchgrass ecotypes: the lowland ecotypes, consisting of solely octaploids, and the upland ecotypes, consisting of both octaploids and tetraploids (Hultquist et al. […]

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