Category Archives: Switchgrass

Char and other Solid Impurities

Bio-oil contains solid contaminants (ash and char), which catalyzes the polymerization and cracking reactions of the bio-oil. The alkali present in the ash such as sodium and potassium also catalyzes cracking reactions. The particulate contents depend on the type of cleaning and filtration system used following the pyrolysis reactor. Cyclone separators are generally used to reduce the particulate contents but […]

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Clemson University/SRNL Process Integration for Switchgrass and Sweet Sorghum to Ethanol

The Clemson University/SRNL Bioethanol collaborative project developed a comprehensive process to convert switchgrass (Panicum virgatum L.) and sweet sorghum (Sorghum bicolor L. including Dale and M81E) to fuel grade ethanol. The project was conducted by Clemson University and the Savannah River National Laboratory (SRNL) originally funded in October of 2008 with continued research through September 2012. In 2010 the research […]

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Improvements in Biomass and Biofuel Outputs

Conventional, molecular, and transgenic breeding efforts will be required to increase biomass and ethanol yields necessary to reach government — mandated fuel benchmark (Gressel 2008; Jakob et al. 2009). Conventional breeding, and to a lesser extent, molecular breeding, has provided modern — day switchgrass cultivars via selection of typically high biomass individuals from native populations. In reality, the domestication process […]

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Stress Resistance

Along with large-scale, intensive production of switchgrass, agronomic trait improvement, such as disease and insect resistance, will become more and more important (Gressel 2008). Native switchgrass has extensive genetic diversity with fair resistance to the majority of potential pathogens (Bouton 2007). However, without knowledge of the genetic basis of disease resistance in switchgrass and the structure of pathogen populations, current […]

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Biofuel Production Processes: Pretreatment

Cellulosic ethanol production process involves a series of steps including preprocessing of feedstock (transportation, grinding, sieving), pretreatment (chemical or biological to remove lignin), enzyme hydrolysis (to produce fermentable sugars), fermentation (for production of ethanol, biomass) and downstream processing (separation of biomass from product, distillation, purification). The cost of ethanol production using lignocellulosic feedstock is relatively high with lower yield based […]

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Modeling Climate Change

In addition to considering environmental sustainability, long-term sustainable biofuel production from switchgrass requires that high levels of biomass production be maintained over time. Field trials have shown that switchgrass yields are sensitive to spatial variation in temperature and precipitation (Casler and Boe 2003; Casler et al. 2004). Future climate change may similarly alter the capacity of biofuel production. Therefore, modeling […]

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Particulates

Particulates of the syngas include ash and char. Ash is composed of minerals such as metal oxides, whereas char is composed of carbon. The most commonly used technology for particulate removal is cyclone separator. Cyclone separator removes particulate by applying centrifugal force on the particle and letting it move downward for collection. Several designs such as 1D-2D (1 dimension width […]

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PH and Temperature Control

The composition of cellulolytic enzymes produced by T. reesei Rut C-30 is influenced by changing pH (Juhasz et al. 2004). An increase in p-glucosidase activity has been reported at pH 6 in comparison with a lower pH range of 4-5 (Tangnu et al. 1981; Nagieb et al. 1985). The purpose of supplied chemicals for the pH control is not limited […]

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Cost Estimates from Model

A summary of estimated costs for supplying a biorefinery with a flow of switchgrass biomass feedstock is provided in Table 11. For the average net yield of 10 Mg/ha, the estimated cost to deliver a flow of switchgrass is $60/Mg (Table 11). This cost is less than the conventional budget estimate reported in Table 5 of $79/Mg based on a […]

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Many Functional Groups

Bio-oil is a mixture of many compounds with different functions groups. Acids, alcohols, aldehydes, esters, ketones, sugars, phenols, gicaols, syringols, furans, lignin derived phenols and extractible terpene with multiple functional groups comprise most of the bio-oil (Mohan et al. 2006; Lee et al. 2008; Guo et al. 2011).

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