Biorefineries characteristics

Sedlmeyer, F. B. (2011). Xylan as by-product of biorefineries Characteristics and potential use for food applications. Food Hydrocolloids, Vol. In Press, Corrected Proof, pp. ISSN 0268-005X... 

The concept biorefinery is discussed in the US National Research Council Report Biobased Industrial Products [4] and by Lynd et al. [7] in much detail. The basic idea is the processing of multiple renewable resources and the production of multiple products in a production complex. Another characteristic of biorefinery is the integration of thermal, chemical, biological and/or cataly-tical processes for an efficient and optimal processing and utilization of the raw materials. Technological, ecological and economic analysis and system design should be implemented to ensure an overall optimization of raw material conversion and product formation in a similar way as for oil refineries. 

Approximately 89 million metric t of organic chemicals and lubricants, the majority of which are fossil based, are produced annually in the United States. The development of new industrial bioproducts, for production in standalone facilities or biorefineries, has the potential to reduce our dependence on imported oil and improve energy security. Advances in biotechnology are enabling the optimization of feedstock composition and agronomic characteristics and the development of new and improved fermentation organisms for conversion of biomass to new end products or intermediates. This article reviews recent biotechnology efforts to develop new industrial bioproducts and improve renewable feedstocks and key market opportunities. 

Catalysis is thus a driver for sustainability and societal challenges [51] and for a sustainable energy [52, 53[. New demand for applications (e.g., the area of biorefineries [54, 55[) and new advances in both the ability to control catalyst characteristics through nanotechnologies [56, 57[ and to understand catalytic reactions [58-62] have greatly renewed the interest in catalysis and changed the research topics and approaches with respect to few years ago. We could thus conclude that catalysis is not only a key element for the sustainability of chemical processes but also that the recent advances in this area have further enhanced its critical role. 

On the whole, the transmitters capture eight Hnks from the senders (73% of total Hnks departing from the senders), interact within themselves through 11 Hnks (with a total absolute weight of 24), and direct 12 Hnks toward the receivers (for a total absolute weight of 26). This characteristic reflects the property of connective fabric, which is essential for the development and success of the biorefinery industry. 

Starch- and sugar-containing crops are quantitatively the most important products of today s agricultural system. Most of the existing biorefinery concepts are based on these plants and they are referred to as first-generation feedstock (vide supra), but they also constitute the backbone of human nutrition. General characteristics of this type of biorefinery are listed in Table 1.1. 

General characteristics of this type of biorefinery are listed in Table 1.2. 

The remaining lignin that is separated from the sugar stream during the pretreatment process can be used for the production of heat and power, which is done very frequently at the moment nevertheless, it could be used in the future as a source of various aromatic compounds. The effective utilization of all the three components would play a significant role in the economic viability of an integrated biorefinery. General characteristics of this type of biorefinery are listed in Table 1.3. 

Table 1.6 Overview of the main characteristics of the different biorefineries...

The knowledge transfer from the research and development level to large-scale production constitutes the first criterion to the industrialization of the vegetable oil biorefinery. Thus, pilot facilities are necessary to be able to evaluate new and innovative technologies from vegetable oil biorefineries. Other important aspects have also to be considered to allow a viable industry such as the choice of the location of the biorefinery, the study of the social and economic characteristics, and the sustainability criteria. 

Biogas is a product that is a part of the majority of biorefinery concepts. This is because of the favorable characteristics of anaerobic digestion, particularly the high energy yield from organic substances, the low cost technology of biogas production, the low demand for substrate composition and quality, and the wide application spectrum. 

Pyrolysis is a thermochemical conversion option that can play an important role in hybrid biorefinery concepts because it offers a flexible way to convert biomass and/or biomass residues into (a precursor for) value-added chemicals and products that enhance the profitability of the biorefinery. Separation/purification/upgrading of pyrolysis oil into biofuels and/or individual chemicals is challenging and poses a broad area of research that may require the development of a whole new type of chemistry, specifically devoted to the physicochemical characteristics of biomass pyrolysis oils. 

Creation of a value-added portfolio of fuels, chemicals and materials from each of the three biorefinery process streams that mimic the diverse product slate characteristic of today s petroleum refineries. Although cellulose fiber is profitably exploited by the paper industry, the hemicellulose and lignin components of wood are generally underutilized. 

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). 

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