Separation, biomass conversion

Of course, the pharmaceutical industry is not the only sector in which process engineering is needed to enhance national security and homeland defense. Also, other areas of process engineering such as model development, optimization schemes, on-line control, catalyst development, new separation methods, biomass conversion, and models using multiple length scales are equally important to include in research efforts. 

Flowchart of yard waste biomass processing plant Biomass conversion leqrires a separate process to break down complex five-cait>on sugars. 

Experiments were carried out in batch-type and flow-type supercritical biomass conversion systems. The batch-type reaction system was the same as reported previously (14). In brief, it consisted of a tube reaction vessel (Inconel-625 5 mL in volume) equipped with a thermocouple and a pressure gage. For hydrolysis reaction, 1 mL of rapeseed oil mixed with 4 mL of water was fully charged into the reaction vessel. The reaction vessel was then heated with molten tin preheated at desired temperatures. It took about 12 s to reach the reaction temperature. Subsequently, the vessel was moved into a water bath to quench the reaction. Reaction time was counted from the time a mixture reached the reaction temperature to when it was quenched. The obtained product was then kept for about 30 min until the two phases separated the upper portion is the hydrolyzed product, while the lower is a mixture of water and glycerol. The upper portion was then evaporated in a vacuum evaporator to remove any water. 

The production of multiple products is generally seen as necessary to increase the economic viability of biomass conversion. This is encapsulated in the concept of a biorefmery , which according to the National Renewable Energy Laboratory (NREL) is a facility that integrates conversion processes and equipment to produce fuels, power and chemicals from biomass [23], Examples of chemicals that can be produced from biomass include ethanol, methanol, furfural, paper, lignin, vanillin, lactic acid, dimethylsulfoxide and xylitol. In many cases, using biomass as a feedstock for chemical production requires an initial step to separate or fractionate the three main components into usable fractions [20, 22], This also maximises the usage of the different biomass components. 

Figure 23.3 shows a general scheme of the processes of biomass conversion. It should be noted that the feed and separation processes are very specific and important for separating the gases from very fine particulate materials, as well as the liquid. However, they will not be described here. The study of the reactors will be discussed later. 

Not the least, catalytic/biocatalytic systems can be very simple separated and recycled by applying an external magnetic force, avoiding the complications associated with the use of rmit operations as catalyst filtration or centrifugation. Hence, several designs of the magnetical-separated com-posite/biocomposite have been developed and appHed for biomass conversion into platform molecule and further to value-added products. 

A biorefinery is the integral upstream, midstream, and downstream processing of biomass into a range of produas. In the classification system lEA Bioenergy Task 42 (described in the next chapter) has differentiated between mechanical pretreatments (extraction, fractionation, separation), thermochemical conversions, chemical conversions, enzymatic conversions, and microbial (fermentation both aerobic, anaerobic) conversions. 

Industrial actors, and their associates in the biomass conversion, are also facing sustainability challenges, and they should aim at the development of processes that are more energy efficient. For instance, the selectivity of processes has a direct influence on energy consumption and less by-product formation implies less separation steps. 

The chemical industries are looking for sustainable growth with a high-energy, efficient biomass conversion approach that can be commercialized into value-added platform chemicals to replace petroleum-derived chemicals (Menon and Rao, 2012). The industrial conversion depends on the selective syntiiesis of products at higher yields, with large-scale production, efficient separation techniques, and tire removal of impurities from renewable resources (Ruppert et al., 2012). The preferred targets of the chemical industry based on raw material, process complexity, productivity, and potential market for the top value-added platform chemicals are listed in Table 26.1. 

Particle Size Reduction. Changes in the physical characteristics of a biomass feedstock often are requited before it can be used as a fuel. Particle size reduction (qv) is performed to prepare the material for direct fuel use, for fabrication into fuel pellets, or for a conversion process. Particle size of the biomass also is reduced to reduce its storage volume, to transport the material as a slurry or pneumatically, or to faciHtate separation of the components. 

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