Biorefinery approaches

The biorefinery approach is the most sound in terms of truly exploiting the potential of an aquatic biomass, and this concept is now becoming accepted on a worldwide basis. In the biorefinery approach, the economic and energetic value of the biomass is maximized, although it must be emphasized that fluctuations in the prices of fossil carbon (coal, oil, gas) raises uncertainty regarding the opportunity to produce biodiesel from aquatic biomass. For example, when the oil price is below US 120 per barrel it is uneconomic to produce biodiesel in this way. On the other hand, an aquatic biomass demonstrates an excellent potential for use as a source of specialty chemicals, with some components also having added value as animal feeds or fertilizers. 

Recent attempts aim at the controlled transformation of cellulose, hemicellulose, and lignin to platform molecules for a potential future biorefinery scenario. In this regard, the U.S. Department of Energy has published studies on potential future platform molecules that could be derived from renewable resources [35, 36]. Tailored transformation of biomass to these platform chemicals could serve as a starting point for biofuel production. This would allow the development of comprehensive biorefinery approaches that incorporate both the production of biofuels and chemicals. The... 

Biomass feedstocks available decentrally will be more commodious for localized biorefinery approach than the exhaustive large-scale and centralized plants driven by cost intensive technology (2). A simplified scheme of biorefinery operations is given in Figure 11.1. 

The biorefinery approach is the promising concept, ideally combining the production of food, materials, and energy from biomass. Following the International Energy... 

The intrinsic heterogeneity and complexity of biomass caU for biorefinery approaches that are adapted to the feedstock and that are impossible to match with current petrochemical technologies. An efficient (thermal) fractionation of the biomass into its main constituents is a key issue. An effective fractionation ensures that each of the main fractions is less heterogeneous than the original material and can be processed further into less complex product mixtures with higher concentrations of the desired chemicals, making their isolation from the mixture more efficient and cheaper. 

The University ofWaterloo continued the development in greater detail and showed from an economic evaluation that the process is an interesting alternative for the conventional production of ethanol. " In 1999, they compared the cost of producing ethanol from ceUulosic biomass via the hybrid thermochemical biorefinery approach, to acid hydrolysis and enzymatic hydrolysis technologies. The results indicate that the production cost of ethanol via the fast pyrolysis-based concept is competitive with the production cost via the conventional approaches. 

As can be seen from Figure 8.6, fast pyrolysis is the primary technology to convert lignocellulosic biomass into biooil, char, and gas. The biooil is feedstock for a subsequent biorefinery approach that aims to further process the biooil into a spectrum of value-added products. This elegant concept is further schematically presented in Figure 8.7. 

Figure 8.10 Lignin Biorefinery Approach (LIBRA), under development at ECN.

Proposals to implement a biorefinery approach for platform chemical production have ignited a debate on whether biorefinery feedstock production threatens food security and increases the rate of deforestation (Ravindranath et al., 2008). It s worrying because the feedstock suitable for biorefinery implementation is procured primarily from forests. Any activity such as feedstock production, which puts considerable pressure on the forest cover, endangers natural heritage and biodiversity (Achten et al., 2013). This chapter discusses various forest-based feedstocks for biorefinery. Moreover, it seeks to elaborate the industrial applications of this feedstock, their characteristics and land requirements (essentially the extent of theoretical deforestation), their production, and procurement. Clearly the influence of biorefinery on woodlands will rely on the nature of the feedstock being used. For example, Brazil utilizes deforested land for sugarcane cultivation and subsequent ethanol production. However, in the case of Indonesia, rain forests were cleared for palm oil production. All of the biorefinery processes require cellulose as the raw material, and since the major source of cellulose in nature is in the form of trees, large-scale deforestation seems to be a plausible end scenario (Gao et al., 2011). 

It can be inferred that the business as usual approach encourages deforestation (forest loss) or nation growth. But it is obvious that deforestation will never promote any country s growth rather it will lead to a loss of biodiversity, GHG emissions from biomass combustion, and human rights violations. Thus several countries contradict this model and appreciate the later model for a sustainability approach. Wicke et al. (2011) clearly demonstrate that an additional demand for feedstock for biorefinery in the future will surely lead to forest cover loss unless and until a proper policy has been framed against this sort of LUC. The same study asserted that the biorefinery approach could be carried out without further forest cover loss by a combination of converting barren land and improving yields. 

OMEGA-3 FATTY ACID PRODUCTION A BIOREFINERY APPROACH... 

Subhadra, B.G., 2010. Sustainability of algal biofuel production using integrated renewable energy park (IREP) and algal biorefinery approach. Energy RoHcy 38, 5892-5901. 

Biodiesel is currently produced mainly from oilseeds leading to the generation of sig-nificant quantities of by-product streams, namely cmde glycerol (10% w/w) and oilseed meals. These by-product streams could be recycled for the production of SCO-derived biodiesel through integrated bioprocesses employing a biorefinery approach. 

Sambusiti, C., Bellucci, M., Zabaniotou, A., Beneduce, L., Monlau, F., 2015. Algae as promising feedstocks for fermentative biohydrogen production according to a biorefinery approach a comprehensive review. Renewable and Sustainable Energy Reviews 44, 20—36. 

---