Reducing the Carbon Footprint of Fuels and Petrochemicals DGMK Conference October 8 – 10, 2012, Berlin, Germany

Biorefineries – Prerequisite for the Realization of a Future Bioeconomy K. Wagemann DECHEMA e.V., Frankfurt a.M., Germany

The current discussion on how to establish a bioeconomy aims in particular at a significant increase of the share of renewable raw materials in the feedstock pool for the production of chemicals and materials; this share currently is around 12%. Such products can be intermediate chemicals, presently already produced from petroleum. Other chemicals, which can be components of new value chains, are also being discussed. In addition materials like biopolymers are already used directly in consumer goods.

These considerations imply a higher demand on renewable raw materials especially from plants. Biorefineries will play an important role in meeting this demand.

The German Government has decided to draw up a roadmap being established by a group of independent experts from industry and academia. This roadmap describes in a systematic way status and perspectives of the different biorefinery concepts. It takes economic and ecological aspects into considerations and analyses the R&D demand.

The following definition is taken as a basis for the analysis:

‘A biorefinery is characterised by having a dedicated, integrative overall approach, using biomass as a versatile raw material source for the sustainable production of a spectrum of different intermediates and marketable products (chemicals, materials, bioenergy and food/feed co-products) by using the biomass components as complete as possible.‘

The analysis considers the following promising concepts :

. Sugar biorefinery and Starch biorefinery . Plant oil biorefinery including Algae lipid biorefinery . Lignocellulose (Cellulose/Hemicellulose/Lignin) biorefinery including Green (green fibre/green juice) biorefinery . Synthesis gas biorefinery . Biogas biorefinery

The roadmap analyses the strengths, weaknesses, opportunities and threats of the different concepts. For several specific examples preliminary economical and ecological assessment were carried out. The lecture will also give examples how these concepts are presently implemented either top down being integrated in existing plants using renewable raw materials as feedstock or top down as standalone plants mostly on a pilot or demonstration scale.

1. Introduction

The term ‘bioeconomy’ stands for the utilization of biological resources in value chains. Such resources can take the form either of biomass, valuable, pharmaceutically active compounds or the metabolic pathways of microorganisms. The current discussion in Germany and Europe on how to establish a bioeconomy aims in particular at a significant increase in the share of renewable raw materials in the feedstock pool for the production of chemicals and materials; this share is presently around 12%. Such products may be intermediate

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chemicals, currently produced from petroleum. Other chemicals, which could become the components of new value chains, are also under discussion. In addition, materials like biopolymers are already used directly in consumer goods.

Such an increased demand for renewable raw materials, especially those from plants, must take into consideration the constraints imposed by the limited availability of agricultural and forestry land. The strong competition for land for the production of food, feed, energy materials and chemicals as well as for nature conservation reinforces the urgency of achieving not only higher yields, but also highly efficient management of biomass. Biorefineries are the key to the requirement of high resource efficiency incorporating economic and ecological aspects: they represent highly integrated processing complexes to ensure that renewables are utilised with minimum waste and maximum sustainability. In this respect a major role will be played by different sectors: agriculture and forestry for biomass production, by the chemical industry for the development of new conversion processes and innovative biobased products, and by plant and equipment engineering with respect to the export potential of technologies to resource-rich countries.

In this context, four German federal ministries, for Education and Research (BMBF), Food, Agriculture and Consumer Protection (BMELV), Economics and Technology (BMWi) and Environment, Nature Conservation and Nuclear Safety (BMU), set up a task force to draw up a ‘Biorefinery Roadmap‘ in the framework of the federal government’s action plans for utilising renewable resources for materials and energy. The Roadmap should create a substantial basis for the strategic development and implementation of biorefineries. Besides citing existing initiatives, it delineates future development options in the light of market demand, pressure on technology, and sustainability as the guiding principle.

The aim of the ‘Biorefinery Roadmap‘ is to analyse and assess prospective future developments in this field. A systematic survey of the current status is coupled with an analysis of the strengths, weaknesses, opportunities and threats of the various biorefinery concepts and their economic and ecological implications. This constitutes a basis for specific recommendations for R&D priorities to develop and operate highly efficient bioefineries by the year 2030.

2. Definition and systematic approach

The integrated production of chemicals, materials and energy based on biomass in one facility creates tremendous potential for synergies. It would permit the coupling of material flows, combined heat and power as well as joint water, wastewater and disposal management, and most importantly economies of scale. At the same time it is imperative to face the challenges resulting from the large-scale accumulation of biomass and from the decentralized and, where applicable, seasonal raw materials supply. Thus the role of raw material logistics and conditioning plays a major role. The framework conditions for the establishment of biorefineries include ensuring the long-term, sustainable supply of these resources in the appropriate quality and quantity and at a viable cost.

The following definition is taken as a basis for the analysis:

‘A biorefinery is an integrative, holistic processing facility, using biomass as a versatile raw material source for the sustainable production of a spectrum of different intermediates and marketable products (chemicals, materials, bioenergy and food/feed co-products) and utilising the biomass components as completely as possible.‘

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The analysis considers the following promising concepts:

. Sugar biorefinery and Starch biorefinery . Plant oil biorefinery, including Algae lipid biorefinery . Lignocellulose (cellulose/hemicellulose/lignin) biorefinery, including Green (green fibre/green juice) biorefinery . Synthesis gas biorefinery . Biogas biorefinery

Basically the biorefinery process chain consists of the pretreatment and processing of biomass, the separation of biomass components (primary processing) and subsequent conversion and refining steps (secondary processing).

Figure 1: Schematic of the biorefinery process chain1

Depending on the biorefinery concept concerned, primary processing involves separating the different biomass components to obtain specific intermediates (e.g. cellulose, starch, sugar, plant oil, lignin, plant fibres, synthesis gas, biogas). Whereas separation takes place centrally at the biorefinery, one or more pretreatment/conditioning processes can take place locally. In secondary processing a greater number of products are derived from the intermediates via additional conversion and refining steps. In a first conversion step the intermediates are further processed wholly or partly into precursors, which in turn are wholly or partly refined into end products at the biorefinery in a further value-added step. Biorefinery products can be semi-finished or finished products. The co-products derived from primary and/or secondary refining are further treated for process energy use or, if suitable and subject to statutory provisions, for food or feed. Biogenic feedstock can be roughly classified as follows:1 1. Renewable raw materials, biomass produced from agricultural and forestry waste which is not used for food or feed. Besides crop and woody biomass, marine biomass also falls into this category. 2. Biogenic waste from agriculture and forestry, the harvest waste from agricultural and forestry production (e.g. straw, beet leaf, forestry waste wood, manure) or biogenic waste from primary refining (e.g. beet pulp, rapeseed cake, potato pulp, corn cobs, animal by-products, black liquor from pulp production, waste algal biomass).

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3. Biogenic waste from industry, process and production residues from industrial processing, such as residual biomass from fermentation (e.g. stillage, digestate) or biogenic waste from food production (e.g. whey, stillage, fruit skins). 4. Biogenic waste accruing from used products (e.g. waste fats, food waste, biobased waste oils, biobased packaging plastic, waste timber).

Figure 2: Schematic of biobased feedstock sources1

Regarding the classification of the various types of biorefineries based on different types of biomass and with diverse product portfolios, a consensus was reached on platform chemicals as a reference point. An intermediate derived from primary refining, which represents the feedstock for secondary refining, is referred to as a biorefinery platform chemical. There are numerous options for biorefinery platform chemicals and the associated concepts; the following biorefinery routes have emerged as particularly promising.

. Sugar biorefinery or starch biorefinery . Plant oil biorefinery, including algae lipid biorefinery . Synthesis gas biorefinery . Biogas biorefinery . Lignocellulose biorefinery or Green biorefinery

In the following chapters these biorefineries will be presented in greater detail and their present implementation status and individual strengths and weaknesses will be analysed.

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3. Sugar and starch biorefinery

Based on the juice of sugar cane and sugar beet from primary refining, sucrose can be derived as a platform chemical.

Figure 3: Example of the processing routes of a sugar biorefinery

In the refinery schematic in Figure 3, the right-hand pathway depicts nothing more than classical bioethanol production. In general, higher value products, such as gluconic acid, can be obtained via the left-hand pathway. Ultimately both bioethanol and sugar production can significantly broaden their product portfolios via this scheme. The starch biorefinery uses cereals, potatoes and cassava as feedstock. Primary refining delivers starch. In this case, too, based on the platform chemical starch following its hydrolysis to glucose, bioethanol production is one pathway, and glucose-based fermentation leading to high-value products the other. By this means starch-processing companies can move ahead up the value chain, examples being the US company Cargill which, building on its starch production, meanwhile produces lactic and polylactic acid, bioethanol and sweeteners, and in Europe Roquette, which has started producing succinic acid. The chance to expand existing structures in the sugar and starch industry represents one of the main strengths of these two approaches. Moreover, the German sugar and starch industry is already well positioned in the European market, the raw material is readily available in Germany, Europe and worldwide, and there is a wealth of expertise in chemical and biotechnological conversion of carbohydrates to draw on. However, although a good academic basis exists in Germany, strategic R&D efforts are required to diversify the range of intermediates derived from secondary refining. Besides this shortcoming, it also cannot be denied that the link between the sugar and starch industry and the chemical industry is weak.

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4. Plant oil and algae lipid biorefinery

The plant oil biorefinery uses oil seeds and oleaginous fruit as feedstock. The most important oil seeds worldwide are rapeseed, sunflower seeds and soya beans, the most important oleaginous fruits include palm oil fruits and kernels, coconuts and olives. Plant oil is the product of primary refining.

Figure 4: Example of a plant oil biorefinery route

Glycerol is of key importance in secondary refining; it can be obtained both by transesterification (for instance in the production of biodiesel) and by hydrolysis. Chemical or biotechnological modifications permit a novel means of accessing products like, for instance, 1,3-propandiol or epichlorohydrin. In addition the fatty acids released by hydrolysis are suitable for further refining into lubricants. Similar to the sugar and starch biorefinery, a decisive advantage is that it is possible to build on the existing infrastructure of plant oil processing and production; here, too, the German plant oil industry is well positioned globally. Additionally, research-intensive SMEs engaged in refining plant oils also, for instance, derive components for plastics production. Furthermore intensive academic research and development efforts are being devoted to this pathway. One weakness is easy to identify: process integration is still under-developed, particularly in the case of bioenergy production, and even primary and secondary refining are rarely integrated in one processing complex. The concept of the algae lipid biorefinery is still in its infancy. The raw material basis is biomass from microalgae, unicellular and paucicellular living organisms which, although they perform photosynthesis, are not classified as plants. Under certain cultivation conditions they are able to accumulate lipids in the form of droplets of oil in the cells.

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Figure 5: Example of an algae lipid biorefinery pathway

The concept shown in Figure 5 will only be economically viable if it is possible to extract high- priced lipophilic compounds, such as carotenoids, and to utilise the residual biomass following oil extraction for energy generation. Algae oil can be further processed to produce valuable products via hydrolysis. Numerous press releases describe a completely different concept: the use of microalgae production primarily to produce fuels. In many cases, however, a realistic assessment will conclude that, given the high energy input for circulating the microalgae suspension with a very low concentration of biomass, for the delivery of CO2 together with the high level of nutrients required as well as for processing the biomass, it is not possible to demonstrate a net energy yield.

5. Synthesis gas biorefinery

Biomass-derived synthesis gas can be generated by several pathways, including straw pyrolysis with subsequent entrained-flow gasification of a pyrolysis oil slurry, wood torrefaction also with subsequent entrained-flow gasification or fluidised bed gasification of dried and suitably conditioned wood. Both chemicals and fuels can be obtained either by the methanol route or the Fischer-Tropsch process. Recently, already with industrial participation work commenced on applying fermentation processes to derive alcohols and carboxylic acid from synthesis gas.

The tremendous strengths of the synthesis gas biorefinery concept are that the lignocellulosic raw material base (agricultural and forestry waste) is not in direct competition with food and feed production and that these resources are generally available in Germany, Europe and globally. An additional bonus is Germany’s vigorous research and development activities in the field of biomass gasification and experience with coal gasification and its scale-up as well as in the chemical conversion of synthesis gas.

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On the other hand, on account of their size, economically viable plants require large amounts of feedstock, plants are highly capital-intensive to build and, for good measure, there is still a lack of product diversity. Furthermore, this concept uses the same raw material base as the lignocellulose biorefinery described in Chapter 6.

6. Lignocellulose biorefinery and green biorefinery

The raw material base is the same as that for the synthesis gas biorefinery. Whereas in the latter case all components of this type of biomass are ultimately converted into CO and H2 (and CO2), in this case nature’s synthesis capability of forming complex structures is exploited. To this end, the lignocellulose is broken down and separated into the three main components cellulose, hemicelluloses and lignin.

Figure 6: Example of a lignocellulose biorefinery pathway

As a result of disintegration, other separation processes and further conversion steps in primary refining, glucose, xylose (C5-sugar) and lignin as a potential source of aromatic compounds become accessible in secondary refining. The sugars are generally used in biotechnological processes as a C-source for the production of diverse intermediates, such as mono- and di-carboxylic acids or amino acids. Another variation is the application of these sugars to produce bioethanol; in this case a second-generation fuel is produced, the added value being created by the use of lignin as a starting material for chemicals. The advantage is that there is no competition for raw materials between food and feed production, there is adequate availability of lignocellulosic materials and there is a high standard of R&D with respect both to disintegration processes and to the chemical and biotechnological conversion of carbohydrates. A further advantage is the potential of Germany’s well-developed pulp industry.

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The weaknesses are competition with the synthesis gas biorefinery and the lack of routes to lignin utilisation for products with higher value added.

In contrast to the lignocellulose biorefinery proper, the green biorefinery depicted in Figure 7 relies on not yet lignified (woody) biomass (particularly grass).

Basically, however, by applying the appropriate, though highly complex separation processes, lactic acid and proteins in particular become available. Nevertheless it is anticipated that such plants will only be feasible with a biogas plant as the central component and chief utiliser of biomass.

Figure 7: Example of green biorefinery pathways

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7. Biogas biorefinery

As in the case of existing biogas plants, the raw material base consists of different types of biomass, provided it is not too lignified. They include wet biomass in the form of waste from agriculture and the food processing industry, communal biogenic waste and also biomass from perennial grasses and maize silage cultivated specifically for this purpose. At present the concept still tends to be theoretical and could only be meaningful under certain conditions: as an integral component of other biorefinery concepts for utilizing waste by returning the methane generated into the production cycle, for instance as a carbon source for specific fermentation processes.

8. New products

Biorefineries are set up both to produce known intermediates of existing value chains and to facilitate access to new chemicals. Access to new chemicals as the building blocks of new products, primarily biobased polymers, is a major goal of existing research activities. For this reason the Roadmap addresses a whole series of chemical compounds with different atomic numbers of C.

C1 Methanol, methane, formaldehyde, C5 Itaconic acid, levulinic acid, glutamic acid, methylamine furfural, pentanediol, isoprene C2 Ethanol, acetic acid, oxalic acid, glycolic C6 Citric acid, gluconic acid, sorbitol, acid, ethylene, ethylene oxide, vinyl hydroxymethylfurfural, adipic acid, lysine, chloride, DME isosorbide, furan-2,5-dicarboxylic acid C3 Lactic acid, 1,2- and 1,3 propandiol, > C6 Fatty acids, fatty acid alkyl ester, fatty acrylamide, 3-hydroxypropionic acid, alcohols, fatty acid amines, long-chain (Di-) acrylic acid, acrylonitrile, acrolein, carboxylic acids, epoxy carboxylic acids epichlorohydrin, propylene, acetone, triacetin C4 Succinic acid, fumaric acid, 1-butanol, Aromatic compounds, aromatic polyols, 1,4- and 2,3-butandiol, tetrahydrofuran, syringyl aldehyde, vanillin, cyclohexane, 1,3-butadiene, maleic acid, methacrylic quinone, terephtalic acid acid, isobutanol, acetoin

Thinking in terms of new chemical building blocks is not new in industry. Some companies are either already developing the production of n-butanol, isobutanol, isoprene, succinic acid, adipic acid and acrylic acid or are planning or building pilot plants. It is not easy to predict which of the chemicals listed will finally be produced on an industrial scale; besides the availability of starting materials, integrating them into existing value chains or creating new ones is highly speculative and depends, among other things, on the requirements of other sectors. For this reason the Roadmap refrains from evaluating the list of potential derivatives.

9. Availability of biomass

All biorefinery concepts are ultimately determined by the availability and price development of the raw materials on which they depend. Whereas for many years prices for agricultural feedstock generally showed a continuous downward trend, since 2005 this no longer applies. Prices have become increasingly volatile which, to a certain extent, has been caused by the market coupling and price convergence of fuels.

With regard to biomass availability, the statistics diverge significantly. From a global perspective and based on the energy content, estimates of the technical potential for biomass range from 100 to over 1500 EJ per year in 2050.2 In the case of the high values,

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the scenarios are based on optimistic assumptions regarding agricultural production efficiency (predominantly animal production). More recent studies, such as IPCC SRREN (2011)3 project more realistic figures of 100 to 300 EJ per year in 2050. If technical and ecological constraints, economic aspects and also, where applicable, socio-cultural criteria are taken into account, the outcome is a significantly lower supply potential. Recent detailed analyses in the framework of an EU project forecast a potential of approximately 10 to 25 EJ per year in 2030 compared to a total energy demand of approximately 70 to 80 EJ per year.4 Obviously this is a scarcely veiled reference to biorefineries’ main competitor for feedstock: the use for energy routes.

This competitive situation is governed not only by the use of biomass for energy, but also by the other pathways for food, feed and, in the case of wood, materials, which bring us full circle to the initial demand for optimum efficiency of all processes, from feedstock processing through to conversion into products – and always subject to the guiding principle of sustainability.

References 1 Roadmap Bioraffinerien (2012) (http://mediathek.fnr.de/roadmap-bioraffinerien.html) 2 IFEU study “Nachwachsende Rohstoffe für die chemische Industrie – Optionen und Potenziale für die Zukunft” 2007, commissioned by VCI 3 IPCC (2011): IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation 4 Rettenmaier et al. (2010): Status of Biomass Resource Assessments – Version 3. Report in the framework of the FP7 Project BEE (Biomass Energy Europe)

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