Thermo-Chemical Processes
for Biomass Conversion (TCP)
Marten Grau
University of Halle (Germany)
Raw Materials from Agriculture and Forestry

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primary raw materials (straw, wood, …)
secondary raw materials (manure,
digestates, …)
nearly every kind of biomass contains a
potential for energy production and/or
material use
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Differences between Organic Materials
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different composition and
concentration of ingredients
wide spectrum of physical and chemical
characteristics
process flows have to adapt
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Examples
1. Biogas production from maize
2. Synthesis gas production from wood
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Planting Requirements
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maize
 annual plant
 intensive arable crop (fertilization,
crop protection, …)
wood (fast growing trees)
 perennial plant, long-term plantation
 extensive crop management
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Harvest

maize and wood (willow, poplar)
harvest with self propelled forage
harvesters
both process chains similar
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result: chaff and wood chips
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Biological Gas Generation
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fermentation of maize silage
result: methane-rich gas (̴ 60% CH4)
Source: K.Purr
Exergy flow:
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Biogas: Pros and Cons
+ well known technology
+ almost closed nutrient cycle
̵
̵ closed phyto-pathogenic cycles
(fusarium spp., clostridium spp.)
risk reduction through disinfection
risk of soil contamination with
inorganic pollutants (heavy metals)
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Thermo-Chemical Gas Generation
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thermo-chemical conversion of dry wood
result: synthesis gas, pyrolysis oil,
pyrolysis charcoal
Source: K.Purr
Exergy flow:
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TCP: Pros and Cons
+
+
+
+
wide range of input materials
higher rate of conversion
higher exergy output
separation of pollutants (organic + inorganic)
̵ open nutrient cycle (ash deposits  P+K loss)
̵ complex technology
̵ breakthrough in biomass gasification
still missing
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Specifications of TCP‘s
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decomposition of organic compounds by heat
trace elements in biomass  influence on
process management
depending on reactor design  varying
gasification products and quality thereof
further use of products requires adapted
technology
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Gasification Technologies
Fixed bed
Fixed bed
Fluidized bed
Fluidized bed
Entrained bed
Own
development
AHT
parallel flow
circulating
circulating
multi-stage
process
multi-stage
process
FÖST e.V. Leuna,
Germany
Kuntschar,
Germany
UMSICHT,
Oberhausen,
Germany
Biomass power
plant Güssing,
Austria
CHOREN,
Freiberg,
Germany
University of
Halle,
Germany
1 MW
200 kW
air
air
80,7 %
74,5 %
Planned power rating
100 kW
660 kW
1 MW
8 MW
Gasification medium
air
air
air
steam
51,4 %
69,7 %
56,2 %
63,8 %
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Source: K.Purr
Cold gas efficiency
Integration of TCP‘s in Agricultural
Value Chains
 highest value added for producers requires short
„pathways“ between producer and consumer
 decentralized solutions for heat and electricity
generation can achieve that
 but: often small plants  higher specific costs
use of secondary effects can increase benefits
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Secondary Effects, Dual-Use
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use of non-conventional raw materials
(solid manure, contaminated wood, …)
fertilizer production by gasification of
sludge
…
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Example 1: Polluted Raw Material

wood coming from phytoremediation
processes (removal of heavy metals and
organic pollutants by plants)
contaminated soils
 risk for farmers: loss of production area
 risk for consumers: pollutants in food or
forage
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Example 1: Polluted Raw Material
 using TCP‘s  pollutants can be separated
from TCP-products
 generating a clean gas, ready for combustion
in gas engines
 after-treatment of residues (ash, eluates)
 recycling of nutrients possible (macro and
micro, current state: expensive)
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Example 1: Polluted Raw Material
current own project:
„Phytoremediation of contaminated
floodplain soils in the Volga River
catchment”
 safe conversion of contaminated
material in a 200kW TCP reactor was
successful
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Example 2: Gasification of Sludge
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closing nutrient cycles (P,K)
process has been established (Ash Dec™)
production of granulated fertilizer
conc. of pollutants < mineral fertilizer
 enhances sustainability
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Take-Home-Message
TCP‘s are ready for many raw materials from
agriculture, forestry and municipalities
decentralized plants for generating poor gas
can be managed by farmers
TCP‘s can be part of closed nutrient cycles
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Thank You for Your Attention!
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