Biorefinery models - Green biorefinery
Publication
date: 05/04/2016
Last
update: 05/04/2016
ABOUT
THE SERIES OF POSTS “BIOREFINERY MODELS”
This
post belongs to a series called “Biorefinery Models”. This series is devoted to
briefly describe the models or concepts of advanced biorefineries which have
emerged in the last few years and that are rising currently. These models are
simplified representations which enable us to understand in a simple way the
structure and characteristics of a general biorefinery type. Some of these models
refer to the type of feedstock while other focus on the technologies involved.
A biorefinery may resemble these models or be the result of variations and
combinations of them.
It
should be noted that although these paradigms are very useful and instructive,
they show limitations in describing and classifying complex systems with high
level of integration. In order to define and describe a specific complex case,
the blog recommends use the classification proposed by IEA Bioenergy Task 42
(Feedstocks / Products / Platforms / Technologies). You can learn more about
the general notion of biorefinery and the different biorefinery classifications
in this section of the blog: BIOREFINERY
CONCEPT.
GREEN
BIOREFINERY MODEL 1,2,3,4,5,6
Green
biomass has become a surplus raw material in many EU regions due to the significant
changes of the dairy farming and meat production sector in the last decade.
Therefore, the interest in alternative uses of grass biomass is currently a
very relevant issue to the agricultural sector. In this sense, the technological
concept of green biorefinery represents an innovative approach that offers new
utilization pathways of green biomass.
One
of the groups that have been working more actively in the development of the
concept, have proposed the following definition (Reference 2): “Green
Biorefineries (GBRs) are complex systems based on ecological technology for
comprehensive (holistic), material and energy utilization of renewable
resources and natural materials using green and waste biomass and focalising on
sustainable regional land utilization”.
The
main features that define the green biorefinery model are shown in the
following factsheet:
Green biorefinery
factsheet
|
|
Feedstocks
|
Fresh wet biomass (green biomass)
Green
biomass is:
• Green grass from the cultivation
of permanent grass lands, closure fields and nature conservation areas.
• Green crops: alfalfa, clover,
sugar beet leaf, potato leaf, immature cereals from extensive land
cultivation.
Green
harvests generate more biomass and proteins per hectare and year than mature
harvests or grain harvests.
The
loss of resources by translocation is minimized if the crops are harvested before
flowering.
|
Primary fractionation
|
Direct
processing of green biomass through thermochemical and biological processes
is complicated due to its high water content and fiber concentration.
Its
initial fractionation represents an essential operation for the green
biorefinery concept. Usually, it is carried out by pressing. Other means of preprocessing
have been studied as thermomechanical dewatering or hydrothermal
conditioning.
|
Main streams
|
Wet
biomass is fractionated by pressing to obtain two streams (Organic Solutions
Platform):
1.
Nutrient-rich juice organic solution (press juice): contains valuable compounds
such as proteins, free amino acids, organic acids, minerals, hormones and
enzymes.
2.
Fibre-rich lignocellulosic press cake (press cake). Beside cellulose and
starch, the press cake contains valuable dyes and pigments, crude drugs and
other organics.
|
Valorization
pathways and products of the press juice
|
• Separation technologies
(centrifugation, agglomeration membrane technology, decantation,
purification, drying, nanofiltration, electrodialysis, chromatography…):
proteins, amino acids mixtures, enzymes, carbohydrates, flavourings,
coulorings…
• Fermentation: ethanol, lactic acid
and its derivatives, organic acids...
After the separation of proteins and other
high value products from press juice, the supernatant can be used as
fermentation media.
|
Valorization
pathways and products of the press cake
|
• Direct use: green feed pellets and
solid fuels.
• Upgrading to fibre products:
insulation materials, fiber boards, horticultural substrates, biocomposites, pulp
& paper…
• Feedstock for lignocellulosic biorefineries:
hydrolysis and fermentation to obtain biofuels, organic acids and
biopolymers.
• Thermochemical conversion
(gasification, hydrothermal liquefaction, pyrolysis…): biofuels.
Thermochemical conversion processes are promising
methods of converting the press cake for energy purposes.
|
Valorization
pathways and products of the residues
|
• Anaerobic digestion: biogas (CHP
or gas-grid biofuel).
The residues generated after processing the
main streams of the green biorefinery are suitable for the production of
biogas.
|
Figure
1. Schematic diagram of the Green Biorefinery Upper Austria in Utzenaich
(extracted from Reference 3)
BIOREFINERIES
AT COMMERCIAL, DEMONSTRATION AND PILOT SCALE 3,6,7,8,9,10,11,12
The table below summarizes the key
information about the main projects related to the green biorefinery model. As can
be appreciated on the table, the industrial efforts to develop the model are
located in Europe.
|
Plant
or technology
|
Location
|
Description
|
Status
|
|
Biowert – The grass factory
|
Brensbach (Germany)
|
Rural green
biorefinery based on grass. Grass fibers are processed to get insulation
material or reinforced composites. Depleted grass juice is used for biogas
generation.
|
Commercial scale
biorefinery
|
|
Green Biorefinery – Havelland type
|
Havelland (Germany)
|
Primary fractionation of
green biomasses and production
of proteins, fermentation media, animal feed and
biogas.
|
Demonstration plant. Annual capacity of 20,000 tons
of alfalfa and grass.
|
|
Green Biorefinery Upper Austria
|
Utzenaich (Austria)
|
Upgrading grass silage to lactic acid, amino acids
and biogas.
|
Pilot plant.
Start-up: 2008.
|
|
Mobile unit
(Netherlands)
|
High-value sustainable protein and fibre based
products from grasses and protein-rich agro-residues (beet leafs).
|
Mobile, small-scale modular process
installation. Capacity of 1-5 tons fresh materials
per hour.
|
|
|
Gramitherm® process
|
Austria
|
The Gramitherm® process extracts cellulose fibres
and juice from raw grass. The fibres are used to produce Gramitherm® (thermal
insulating boards) and the juice to obtain biogas or nutritive concentrate
for animal food.
|
Pilot plant
|
Figure
2. Biowert factory (extracted from Reference 8)
_________________________________________________________________________________
REFERENCES
1 B. Kamm,
M. Kamm: “Principles of biorefineries”.
Appl Microbiol Biotechnol (2004) 64: 137–145.
2 B. Kamm,
P. Schönicke, M. Kamm: “Biorefining of
green biomass – technical and energetic considerations”. CLEAN 37 (1),
(2009) 27-30.
3 M.
Mandl: “Green Biorefinery - An overview”
(Presentation). Danish Crop Production Conference, Herning, 11/01/2012.
4 “Biorrefinerías.
Situación Actual y Perspectivas de Futuro”. Genoma España /CIEMAT.
5 “The
European Biorefinery 2030 Vision”. Star-COLI BRI -Strategic Targets
for 2020 – Collaboration Initiative on Biorefineries.
6 S. Xiu, A.
Shahbazi: “Development of Green
Biorefinery for Biomass Utilization: A Review”. Tr Ren Energy, 2015, Vol.1, No.1, 4-15.
7 IEA
Bioenergy Task 42 Biorefining. Sustainable
and synergetic processing of biomass into marketable food & feed
ingredients, products (chemicals, materials) and energy (fuels, power, heat). Wageningen, the Netherlands, August 2014.
8 www.biowert.de (accessed on 3rd April 2016).
9 B. Kamm,
Ch. Hille, P. Schönicke, G. Dautzenberg: “Green
Biorefinery Demonstration in Havelland/Germany”. Biofuels Bioprod. Bioref.,
Special Issue Biorefinery 4 (2010) 253-262.
10 M. Schaffenberger,
J. Ecker, R. Essl, W. Koschuh, M. Mandl, H. Schnitzer: “Green biorefinery - Production of amino acids from grass silage juice”,
CHISA 2012 - 20th International Congress of Chemical and Process Engineering
and PRES 2012 - 15th Conference PRES (Prague, Czech Republic 25-29/8/2012).
11 grassa.nl (accessed on 3rd April 2016).
12 gramitherm.ch
(accessed on 4th April 2016).
