Thermo-Chemical Processes for Biomass Conversion (TCP)

Marten GrauUniversity of Halle (Germany)

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Raw Materials from Agriculture and Forestry

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

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 maize2. Synthesis gas production from

wood

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Planting Requirements

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

result: chaff and wood chips

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Biological Gas Generation

fermentation of maize silage result: methane-rich gas ( 60% CH4)

Exergy flow:

Sou

rce:

K.P

urr

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Biogas: Pros and Cons+ well known technology+ almost closed nutrient cycle

B closed phyto-pathogenic cycles(fusarium spp., clostridium spp.)risk reduction through disinfection

B risk of soil contamination with inorganic pollutants (heavy

metals)

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Thermo-Chemical Gas Generation

thermo-chemical conversion of dry wood

result: synthesis gas, pyrolysis oil, pyrolysis charcoal

Exergy flow:

Sou

rce:

K.P

urr

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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)

B open nutrient cycle (ash deposits P+K loss)

B complex technologyB breakthrough in biomass gasification

still missing

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Specifications of TCP‘s 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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Fixed bed Fixed bed Fluidized bed Fluidized bedEntrained

bedOwn

development

AHT parallel flow circulating circulatingmulti-stage

processmulti-stage

process

FÖST e.V. Leuna,

Germany

Kuntschar,Germany

UMSICHT, Oberhausen,

Germany

Biomass power plant Güssing,

Austria

CHOREN, Freiberg,Germany

University of Halle,

Germany

Planned power rating

100 kW 660 kW 1 MW 8 MW 1 MW 200 kW

Gasification medium

air air air steam air air

Cold gas efficiency

51,4 % 69,7 % 56,2 % 63,8 % 80,7 % 74,5 %

Gasification Technologies

Sou

rce:

K.P

urr

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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

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

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!