Biorefineries can produce chemicals and feels from biomass on several integrated platforms (Figure 14.8) (WEF, 2010).

1. The biochemical (sugar) platform, based on the biochemical conversion of biomass, focusing on sugar fermentation, and including steps dedicated to products separation and purification.

2. The thermochemical platform, based on the thermochemical conversion of biomass focusing on the gasification of carbonaceous materials and lignocellulosic biomass.

3. The microorganism platform, focusing on algae biomass cultivated in raceway type ponds or in photobioreactors.

The biorefinery concept considered by the National Renewable Energy Laboratory is based on two different primary platforms integrating various routes included in the biorefinery structure (NREL, 2009):

• The biochemical (sugar) platform performs the biomass breakdown into sugars based on chemical and biological processes:

• If lignin is the result of pretreatment and

enzymatic hydrolysis, two steps can be involved in its further transformation:

— lignin upgrading, to etherified gasoline;

— lignin pulping to high quality paper.

• If aqueous sugars result after pretreatment and enzymatic hydrolysis, they are involved in fermentation processes, resulting in ethanol, butanol, and hydrogen.

• The thermochemical platform is based on the biomass conversion onto synthesis gas through gasification, pyrolysis or hydrothermal conversion.

• Gasification results in syngas, which can be further transformed in alkanes, methanol or hydrogen by Fischer—Tropsch, catalysis, water—gas shift processes.

• Pyrolysis and hydrothermal conversion result in biooil, which is further transformed during the following processes:

— upgrading, when liquid fuel results;

— catalytic reforming, resulting in hydrogen;

— extraction, when various chemicals are obtained;

— cross-linking resulting in various (bio) materials.

The third platform—microorganism platform—has been included in the biorefineries structure by the National Renewable Energy Laboratory (WEF, 2010). This structure demonstrates that various processes can occur in a complex biorefinery, similar to a conventional oil refinery. This similarity was also graphically demon­strated by Kamm et al. (2006) (Figure 1.3).

There are also some unclassified biorefineries, which include (de Jong and van Ree, 2006) side and waste streams, MBR, most generation III biorefineries, and consortia of different industries. They are expected to play a significant role in the future, since the classic concept of biorefinery is tightly linked with the progress of agriculture, the efficiency and availability of food and feed production, with major consequences for the prime arable land (PP, 2012). Considering these problems, it is essential to promote integrated biorefinery models, which would be able to surpass the challenges address­ing retaining and recycling of phosphorous, finding new sources of soil organic carbon, maintaining biodiversity by adequate measures (PP, 2012; Star-COLIBRI, 2011). Besides, a new and challenging development began to be focused on the integrated valorization of organic waste streams, such as agrofood by-products, effluents, resulting in new value-added chemicals, biofuels, biomaterial, and water (PP, 2012; Liu et al., 2010; Visvanathan, 2010; Laufenberg et al., 2003).

This way, the integration of biorefinery platforms would be able to generate the synergism, as the underlying concept of industrial ecology. By closing material cycles and cascade utilization and recycling, it would be ensured a multilevel, explicitly integra­tive, multifunctional incorporation of raw materials, processes, and products, belonging to various industrial systems, simultaneously with preventing resource loss by source reduction and waste minimization along the entire biorefinery value chain. A full overview of the platforms, products, feedstocks and conversion pro­cesses is given in Figure 14.9 (de Jong and Marcotullio,

2010) .

Moreover, the eco-efficiency would become the lead­ing concept governing the full system, since processes for biomass treatment and conversion should be resource efficient in terms of materials and energy use and long lifetime of goods and products, along with con­sumption of auxiliaries, and should avoid adverse

Conversion Processes, Methods and Techniques Employed by Biorefineries to Transform the Raw Biomass into Commercial Products—cont’d

TABLE 14.4 Conversion Process Description Products References Fischer—Tropsch Synthesis — Catalytic conversion of sugars into liquid hydrocarbons (C1—C50) — The process in selective depending on temperature, pressure and catalysts Synthetic fuel Demirbas, 2010; Lappas and Heracleous, 2011; NREL, 2009 Hydrogenation — Hydrotreatment of biooils, resulting hydrotreated renewable jet fuels (HRJ) — Removes oxygen and others impurities from organic oils (extracted directly from feedstocks with high oil content or produced by pyrolysis) HRJ—hydrotreated renewable jet fuels, with similar properties as kerosene Conversion of Syngas to Methane (SNG) — Thermal gasification and particular Fischer—Tropsch reaction SNG—synthetic natural gas (a good substitute of the natural gas) Martin and Grossmann, 2012 Aerobic Digestion — Conversion of biodegradable waste or energy crops into a gaseous fuel biogas — Conversion efficiency is about 70% Biogas (50% methane) Martin and Grossmann, 2012 Catalytic Thermochemical Conversion — Increases the yield and optimize the composition of output products of thermochemical conversion — Helps in overcoming the problematic qualities of biooil (thermal and temporal instability) — Catalyst can be incorporated during or after the production process, or in both stages (activated alumina, silicate, Y-zeolite, ZSM-5) Pyrolysis oil (biooil) which is a chemical intermediate or directly as liquid fuel Carlson et al., 2009; de Wild, 2011; Sharara et al., 2012; Zhang et al., 2009

Optimally and flexible use of raw

materials in primary refinery

Valorization and processing of all biomass components, in

integrated and linked systems

FIGURE 14.7 Levels of integration and multifunctionality already realized in biorefineries. Source: Adapted upon Wagemann (2012). Adapted with the permission of the coordinator of "Biorefineries Roadmap as part of the German Federal Government action plans for the material and energetic utilization of renewable raw materials" brochure on behalf of The Federal Government, Professor Kurt Wagemann. (For color version of this figure, the reader is referred to the online version of this book.)

and by-products are quite numerous and diverse; a sim­ple approach for the estimation of production economics would be always opportune, so as to offer valuable in­formation about the relative feasibility of various pro­duction alternatives and routes. For example, Melin and Hurne (2011) developed an algorithm to find "the
production route with the minimum production costs for a biofuel or a chemical, for each raw material, when the process and the economic parameters occur in a known range". Other several studies have estimated biofuel production costs from corn stove through gasifi­cation and Fischer—Tropsch routes (Demirbas, 2010;

Batsi et al., 2012; Swanson et al., 2010). The objective was to compare capital investment costs and production costs for various biorefinery scenarios.

Building a bio-based economy must be able not only to solve the current economic difficulties but also to generate an economic system with minimal impact to the environment.

Even though regarded as similar to petroleum refin­ery, a comparison of the biorefinery and petrochemical value chains show some similarities but also a large number of differences. Both result in complex product trees, but one of the most relevant differences consists in compositions of fossil raw materials and biogenic raw materials (Kamm et al., 2006; Wagemann, 2012). Table 14.5 illustrates some similarities and differences between two value chains.

Consequently, for decision-making process, it is necessary to develop a methodology to drive decisions on biorefinery, with a focus on product design and pro­cess. Transition to a biorefinery economy could involve significant investments in infrastructure to produce, store and sell biorefinery products to customers (Demirbas, 2010). A number of questions related to bio­refinery diagnosis can be addressed using SWOT
analysis. Such an investigation of the opportunities and strengths, weaknesses and threats of biorefineries as developed by IEA within the Task 42 is illustrated in Table 14.6 (de Jong et al., 2009).

The concept of eco-efficiency—defined as "creating more value with less impact"—has been developed by The World Business Council to weigh and compare products and technologies in both aspects: environ­mental pressure and economic significance (WBCSD, 2000). The Organization for Economic Co-operation and Development (OECD) has defined eco-efficiency as the effectiveness with which ecological resources are used to meet human needs.

Integrating the issues concerning the environmental impacts and economic value resulting from biorefinery processes allows decision makers in the business world to evaluate and compare products and technologies simultaneously, from both points of view. Organiza­tions could be supported to establish measurable objec­tives of eco-efficiency and to facilitate comparisons between companies and business sectors by the stan­dardization of definitions and decision system for calculating and reporting eco-efficiency indicators. The environmental impact ratio, defined in Figure 14.11,

reflects how much environmental impact per environ­mental credit occurs in the product system (Hong Chua and Replace with Steinmtiller, 2010; Kim and Dale, 2004). A scenario with a greater eco-efficiency would be more sustainable, which means that it would offer more economic value per unit of environmental impact (Fig. 14.11).

Some eco-efficiency indicators were developed for different levels of biorefinery integration, following the physical flows of materials and energy (Hong Chua and Steinmtiller, 2010):

Level 1 addresses process integration and involves the key processes (receiving and preparation of feedstock, retreatment, conversion to bioproduct, and wastewater treatment system).

Level 2 refers to agriculture integration, which means that feedstocks, including agricultural waste, are supplied in the biorefinery system at the business level that is involving low costs, while biofuels, bioelectricity and biochemicals from biorefinery are sent to the agricultural sector.

Level 3 involves livestock farming integration at the business level, meaning that the organic waste from farms are supplied to the biorefinery system, while animal feed products are sent to the farm.

Estimated costs of production in biorefinery sys­tems may be hampered by a number of driving forces who can change their direction of action and/or importance in time (agricultural development, raw material costs, production scale, competing markets evolution, their demands and access, waste recovery

TABLE 14.5 Comparison of Biorefinery and Petrochemical Value Chains (Wagemann, 2012) Value Chain Biorefinery Petrochemical Raw Materials Biomasses: very complex mixture of organic compounds Mineral oil, natural gas: mixture of hydrocarbons Carbon and heteroatoms (poor in hydrogen, rich in oxygen) Carbon and hydrogen (almost no hetero atoms, poor in oxygen) Contains inorganic compounds Contains virtually no inorganic compounds Hydrous Waterless Primary Refinery Thermal and thermocatalytic (syngas) as well as biochemical (biogas) cleavage into simple molecules Distillation and thermal and thermocatalytic cleavage into simple molecules Secondary Refinery Build-up complex molecules from simple precursors (bottom-up principal) Processes Thermochemical, thermocatalytic and chemocatalytic processes Product Classes Chemicals and materials Combustibles and fuels Source: Adapted with the permission of the coordinator of "Biorefineries Roadmap as part of the German Federal Government action plans for the material and energetic utilization of renewable raw materials” brochure on behalf of The Federal Government, Professor Kurt Wagemann.

TABLE 14.6 SWOT[1] Analysis of Biorefineries Processes (de Jong et al., 2009)

Weaknesses

• Adds value to the sustainable use of biomass

• Maximizes biomass conversion efficiency—minimizing raw material requirements

• Produces a spectrum of bio-based products (food, feed, materials, and chemicals) and bioenergy (fuels, power and/or heat) feeding the full bio-based economy

• Strong knowledge of infrastructure available to tackle any nontechnical and technical issues potentially hindering the deployment trajectory

• Is not new, and in some market sectors (food, paper, etc.), it is common practice

Opportunities

• Make a significant contribution to sustainable development

• Challenging national, European and global policy goals—international focus on sustainable use of biomass for the production of bioenergy

• Biomass availability is limited so the raw material should be used as efficiently as possible—i. e. development of multipurpose biorefineries in a framework of scarce raw materials and energy

• International development of a portfolio of biorefinery concepts, including designing technical processes

• Strengthening of the economic position of various market sectors (e. g. agriculture, forestry, chemical and energy)

• Broad undefined and unclassified area

• Needs involvement of stakeholders from different market sectors (agro, energy, chemical,.) over the full biomass value chain

• Most promising biorefinery processes/concepts not clear

• Most promising biomass value chains, including current/future market volumes/prices, not clear

• Still at a stage of studying and concept development instead of real market implementation

• Variability of quality and energy density of biomass

Threats

• Biorefinery is seen as hype that still has to prove its benefits in the real market

• Economic change and drop in fossil fuel prices

• Fast implementation of other renewable energy technologies filling market needs

• No level playing field concerning bio-based products and bioenergy (assessed to a higher standard)

• Global, national and regional availability and contractibility of raw materials (e. g. climate change, policies, and logistics)

• High-investment capital for pilot and demonstration initiatives difficult to find, and existing industrial infrastructure is not depreciated yet

• Fluctuating (long-term) governmental policies

• Questioning of food/feed/fuels (land use competition) and sustainability of biomass production

• Goals of end users often focused upon single product

and recycling alternatives, storage and production costs, distribution costs, etc.), which could be associ­ated with the components of a complex system with various boundaries (Figure 14.12; Demirbas, 2010; Kim and Dale, 2004).

Life cycle assessment (LCA) is an especially useful tool to investigate the environmental performance of

product and/or technologies. The problem to be solved in the case of biorefineries is not a simple one because these systems are characterized by some particularities that need to be considered in evaluating the processes on an LCA basis and to ensure correct results in terms of eco-efficiency (for example, sometimes it is not obvious which product should be the main output;

FIGURE 14.11 Integration of economic analysis and environmental impact for eco-efficiency (ADP, abiotic resources depletion potential; GWP, global warming potential; ODP, ozone layer depletion po­tential; POCP, photochemical oxidation potential; HTP, human toxicity potential; ETP, ecological toxicity potential; AP, acidification potential; EP, eutrophica­tion potential; NPV, net present value; IRR, internal rate of return). (For color version of this figure, the reader is referred to the online version of this book.)

Environmental impact Environmental credit

Hong Chua and SteinmUller, 2010; Laser et al., 2009). Further, the system boundaries could be different if the biorefineries are nonintegrated or integrated and this can determine the selection of system boundaries, which could also affect the eco-efficiency results, while allocation issues in particular are both important and somewhat controversial (Figure 14.12). A very common approach considers that all biomass is local since this could improve the selection of crops and cropping systems for local biorefineries, reduce opportunities for agenda — driven manipulation of data and opportunities for system integration and waste utilization could be better exploited (Kim and Dale, 2004). The functional unit could be chosen as unit area of land allocated for crop biomass for a certain time period since cropping systems play an important role in the environmental performance of bio-based products, while impacts assessment could address global warming potential, nonrenewable energy, crude oil con­sumption, water use, acidification, eutrophication, biode­gradability, less toxicity, etc. (Laser et al., 2009; Demirbas,

2010) . In their study, Hong Chua and Steinmuller (2010) have identified the following main environmental influences for a biorefinery: energy consumption, material consumption, GHG emissions, acidification, and eutro­phication. The eco-efficiency indicators used to account for these environmental influences are as shown in Table 14.7.

Ensuring biorefinery eco-efficiency is one of the most relevant objectives of Task 42 of IEA in parallel with the projection of new perspectives in terms of competitive­ness, sustainability, and safety of processing routes for biogenic raw materials to guarantee the concurrent fabrication of biofuels, commodity chemicals, new mate­rials, heat and power.