Category Archives: Pretreatment Techniques for Biofuels and Biorefineries

Pretreatment Effect on the Structure of Lignocellulose

Most of the chemical pretreatment technologies that have been described herein are effective on one or more factors that contribute to lignocellulosic recalcitrance, as shown in Table 8.6. Table 8.7 summarizes the main advantages and disadvantages of these pretreatment technologies. Each method discussed shows the ability to take the complex carbohydrate and depolymerize the substrate to a lower fraction for […]

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Independent Components Models

Independent components models incorporate the notion of ‘pseudo-component’. Fig­ure 11.2d gives a typical example of pyrolysis with multiple decomposition levels. The combination of ‘pure’ components decomposing in the same system at differ­ent temperatures would be equivalent to the reaction pattern in Fig. 11.2b. As the temperature of the biomass particles increases, the stability of the solid macromolec­ular matrices changes accordingly. […]

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Alternating Current Plasma Torches

AC plasma torches are more promising for industrial applications and technologies requiring relatively high powers (e. g., waste treatment). Figure 12.3a represents the typical schematic diagram of a power-supply circuit. The power-supply system in this case is essentially cheaper and more reliable, rather than power-supply systems of DC plasma torches. Their maintenance is easier. The thermal efficiency of AC

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Pretreatment with Solid Acid Catalysts

Solid acids are widely used for the study of biomass hydrolysis that will be introduced in Sect. 15.3 in detail. The hydrolysis mechanistic route of a water-soluble polysac­charide consists of the following steps: (1) The soluble polysaccharide diffuses onto the surface acidic sites of a solid acid; (2) в-1,4 glycosidic bonds access to the acidic sites; and (3) These bonds […]

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Enzymatic Hydrolysis of Pretreated SB/SL

Inherent properties of SB/SL cell wall make them resistant to cellulase mediated act for releasing monomeric sugars from hemicelluloses or cellulose. Pretreatment of SB/SL increase the accessible surface area and crystallinity of holocellulose which ameliorates the enzymatic action, in turn yielding optimum sugars recovery [14]. Table 16.4 summarizes the enzymatic hydrolysis profile of SB/SL after various kinds of pretreatment methods […]

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Characterization of Pretreated Pine Sawdust Samples

Effect of pretreatment (organosolv extraction, ultrasonic treatment, and NaOH treat­ment) on the microstructure of pine sawdust was analyzed using SEM. Comparison of the changes in microstructure of pine sawdust before and after the organosolv extraction pretreatment is shown in Fig. 19.1a-d. The SEM pictures clearly show that the microstructure of pine sawdust changed after pretreatments. Compared with the nicely presented […]

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Gasifier Reaction Modeling

Gasifier performance could be expressed in terms of gasification efficiency and product quality, such as heating value and the amount of desired product gas. Math­ematical modeling and simulation of the gasification process provides qualitative information on the gasifier performance, such as the effect of feedstock, design pa­rameters, and operating conditions of the process even though it is not very accurate. […]

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Operability

Biomass particles are generally difficult to fluidize, such that a denser and more homogeneous inert particle media (generally sand) is employed as a fluidization media to improve transport phenomena. Bench and pilot-scale continuous operation of a pyrolysis BFB has been demonstrated by Dynamotive. Char removal from the reactor can be an issue: if char is very fragile, its particle size […]

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