Green Biorefinery - Primary Processing and Utilization of Fibres from Green Biomass
Currently, the structure of agriculture in Austria is strongly changing, characterised by a decrease of grassland utilisation for production of cattle feed (milk production), thus, resulting in a steady increase of excess grassland areas. In order to keep these areas cultivated - which is essential for the highly desirable preservation of cultural landscape of Austria - new innovative utilisation pathways for green biomass are required. On new promising utilisation pathway for green biomass is offered by the technology concept of GREEN BIOREFINERIES. Today, petroleum refineries generate efficiently a multitude of products from crude-oil at a very large scale. Similarly, GREEN BIOREFINERIES process and convert the raw material "green biomass" (e.g. grass, clover, lucern) into a range of individual marketable products (multi-product-system) based on deployment of sustainable zero-waste technologies.
Products generated in a GREEN BIOREFINERY may include (cf. Fig. 1):
- Bulk chemicals (e.g. organic acids like lactic acid, solvents like ethyl-lactate).
- Fuels (e.g. ethanol, acetone, butanol, ester).
- Food / feed (e.g. amino-acids, protein products, peptides).
- Fibre products (e.g. fibreboards, biocomposites, insulation material).
- Fine chemicals (e.g. flavours, chlorophyll, pigments).
- Biogas (=> electricity + heat).
Implementation of the technology concept of GREEN BIOREFINERIES will have a strong positive impact on the economic development of rural regions (which in many cases are also disadvantaged regions), e.g. by stabilizing current grassland cultivation / current farms and by becoming attractive as location for new commercial and industrial enterprises.
Development of the GREEN BIOREFINERY technology is context-dependent, as the "one size fits all" approach is not applicable with technologies utilizing renewable resources due to regional differences with respect to climate, size and product orientation of farms, regional transport infra-structure etc. The AUSTRIAN version of the GREEN BIOREFINERY technology is characterised by the following features (cf. Fig. 2):
- production of lactic acid as key product (bulk chemical of the future): When utilising green biomass as primary resource of a GREEN BIOREFINERY, the storage-problem has to be solved, i.e. green biomass has to be conserved for longer periods of time in order to allow continuous year operation of the GREEN BIOREFINERY installation. One approach to tackle this problem - which is already well established in agriculture - is to subject green biomass to an ensilage process, in the course of which lactic acid is produced by means of appropriate micro-organisms (solid state fermentation). This lactic acid serves on the one hand as conservation agent and is, on the other hand a valuable marketable bulk chemical with an ever increasing market.
- combination of central and decentralized (localized) units: Some of the unit operations constituting the GREEN BIOREFINERY technology, will be developed such, that they can be operated in small / medium sized decentralized (localized) units as close to the biomass feedstock as possible (e.g. ensilage of green biomass, mechanical fractionation of silage), thus reducing negative impact to environment due to transportation of primary resources to a minimum. Only the remaining unit operations will be will be realized in central large scale units taking advantage of economy of scale. Combining decentralized and central units fits best to the specific conditions of agriculture in Austria (e.g. small sized farms).
- flexibility with respect to processed raw materials & generated products: As green biomass is composed of components of different levels of molecular structure, in principle, products of different molecular complexity can be derived in a GREEN BIOREFINERY: Simple molecules (e.g. lactic acid, ethanol), complex molecules (e.g. amino acids, proteins), complex structures (e.g. fibres) and energy (e.g. biogas). In order to achieve long term viability of this technology, it has to be flexible enough with respect to the primary raw materials processed as well as with respect to the range of generated products. This flexibility is required to adapt GREEN BIOREFINERIES to changing market situations. A key product at present might not be a key product of the future.
Considering the fact, that the fibre fraction (press cake) is the largest material stream encountered in a GREEN BIOREFINERY, the overall economic efficiency of a GREEN BIOREFINERY is strongly determined by the economic efficiency of converting this fibre fraction into marketable value added fibre products. However, an adequate assessment of the economic efficiency of a GREEN BIOREFINERY is essential for industrial enterprises when deciding whether to invest in a GREEN BIOREFINERY installation (pilot and/or production scale) or not. Therefore this project has the following general objectives:
- identification of possible industrial fibre products based on fibres from green biomass,
- development of fundamentals for design, construction and operation of a GREEN BIOREFINERY installation on pilot / production scale,
- assessment of the economic efficiency of a GREEN BIOREFINERY AUSTRIA.
Content and Structure of the Project
The project consists of 6 work-packages (cf. Fig. 3):
- WP1: preparation of primary raw materials & mechanical fractionation of these raw materials,
- WP2: primary processing of press cake & technologies for obtaining defined fibre fractions,
- WP3: analytics,
- WP4: fibreboards based on fibres from green biomass,
- WP5: adhesives & fillers for the construction sector based on fibres from green biomass,
- WP6: economic analysis & project coordination.
Work-package WP1 is devoted to preparation of primary raw materials "grass" and "grass silage", respectively (i.e. cultivation, harvesting, ensiling process) and to optimisation of the essential process unit "mechanical fractionation" of the previously prepared primary raw materials into a liquid phase (press juice) and a solid phase (press cake). Optimisation criteria include: (1) Maximum yields of water soluble lactic acid and amino acids in the press juice and (2) minimum damage of fibres in the press cake.
Content of work-package WP2 is performing tests with respect to technologies for primary processing of the press cake and for obtaining specific well defined fibre fractions from this press cake: Activities will concentrate on testing and optimising technologies for (1) further disintegration of the press cake in order to increase the yield of "true" fibres (i.e. reduction of fibre diameter but no reduction of fibre length), (2) fibre size classification (e.g. separation of small & large particles and of specific fibre fractions with well defined fibre length & diameter distributions), (3) reduction of odour emitted by fibres from green biomass, (4) chemical disintegration of specific fibre fractions in order to obtain well purified fibres for specific applications and (5) energy efficient drying methods for press cake.
Work-package WP3 is devoted to analytics with respect to the previously described two work packages as a pre-condition for quantification of the efficiency of the investigated process units (e.g. achievable product yields, separation degrees, conversion rates etc.). Parameters planned to be measured include: (1) Chemical composition of specific material streams, e.g. primary raw materials grass / grass silage and of press cake and press juice obtained by mechanical fractionation of the primary raw materials, (2) fibre size distribution (length & diameter), (3) morphology of fibres, (4) mechanical properties of elementary & technical fibres (e.g. linear density, tenacity, elongation) and (5) water retention behaviour.
Content of work-packages WP4 & WP5 is to carry out lab & pilot scale tests regarding optimisation of manufacturing of prototype fibreboards and adhesives & fillers for the construction sector based on well defined fibre fractions from green biomass as raw material. These tests are performed in close co-operation with well known Austrian manufacturers of these fibre products.
Finally, in work-package WP6 an economic analysis of a GREEN BIOREFINERY AUSTRIA is performed with a strong focus on respective contributions of the fibre fraction.
Expected Results (Deliverables)
- results of tests regarding the essential process unit mechanical fractionation of green biomass (grass / grass silage) and suggestions how to improve the efficiency of this process unit.
- results of pilot scale tests regarding technologies for the process unit primary processing of the press cake, e.g. technologies for further disintegration of the press cake, for separation of specific fibre fractions with well defined fibre length & diameter distributions, for reduction of odour etc.
- prototype fibreboards and prototype adhesives & fillers for the construction sector with specific fibre fractions from green biomass as raw material,
- interpretation of measured properties of these prototype fibre products based on fibres from green biomass as well as suggestions about how these properties can be improved,
- assessment of the economic efficiency of a GREEN BIOREFINERY AUSTRIA.
DI Dr. Bruno Wachter, DI Michael Mandl
Institut für Nachhaltige Techniken und Systeme (JOINTS)
Cooperation partners research
Ao. Univ.-Prof. DI Dr. Michael Narodoslawsky
TU-Graz, Institut für Ressourcenschonende und Nachhaltige Systeme (RNS)
Ao. Univ.-Prof. DI Dr. Senad Novalin
Universität für Bodenkultur, Institut für Lebensmitteltechnologie (ILMT)
Univ.-Prof. DI Dr. Ingo Marini
TU-Wien, Institut für Verfahrenstechnik, Umwelttechnik und Technische Biowissenschaften
DI Dr. Markus Neureiter
IFA-Tulln, Abteilung für Umweltbiotechnologie
Univ.-Doz. Dr. Karl Buchgraber
Bundesanstalt für Alpenländische Landwirtschaft, Institut für Pflanzenbau und Kulturlandschaft
DI Dr. Christian Krotscheck
NATAN - Techn. Büro für Verfahrenstechnik DI Dr. Christian Krotscheck
DI Dr. Stefan Kromus
BioRefSYS - BioRefinery Systems
Cooperation partners economy
DI Dr. Martin Steinwender
Fritz Egger GmbH & Co - Spanplattenwerk
Dr. Bernhard Maier
DI Werner Lorenz; GF Georg Reithmayer
LACTOPROT Alpenländische Milchindustrie und Handels AG
International cooperation partners
Assist.-Prof. Dr. Karin Stana-Kleinschek, Assist.-Prof. Dr. Majda Sfiligoj-Smole
University of Maribor, Faculty of Mechanical Engineering, Laboratory for Characterisation and Processing of Polymers (LCPP)