Project meeting of STEP at the site of the company ATS - Agro Trading & Solutions in Hardegsen (Photo: DBFZ)

Validation market potential Biomass gasification Biomass furnace

Project ID 03KB091

FlexiTorr - Flexibilization of energy supply in small bioenergy generation systems due to the use of torrefied fuels

Torrefied woodchip pellets (Photo: DBFZ)


  • 01.09.2013 – 31.12.2016


DBFZ Deutsches Biomasseforschungszentrum gemeinnützige GmbH
Torgauer Straße 116
04347 Leipzig

André Herrmann – project coordinator
Telephone: +49 (0)341 2434-573

Kay Schaubach – former colleague


03KB091B - Burkhardt GmbH

Associated partners

Cooperation partners



Results are only available in German.


The project deals with the suitability of torrefied fuels for the use in small bioenergy generation systems. This implies more precisely the energy supply through small-scale gasification plants and small-scale furnaces. Background is the intention to make the technology of torrefaction usable for small decentralized applications and appears supremely promising.


The aim is to identify the suitability of torrefied biomass pellets for energy supply through small-scale gasification plants and small-scale furnaces. Possible effects on the contribution and flexibility of small bioenergy generation systems on demand-oriented decentralized electricity and/or heat supply are examined as well as the ecological and economic potential of these conversion paths. The analysis of the market potential is part of a final road-map-report.



The first step is to acquire and characterise the needed fuels. Furthermore torrefied fuels are needed in three different torrefaction rates. Feedstock selection and fuel production is supervised and material samples are taken by the DBFZ.

Combustion experiments are performed in a boiler plant (< 100 kW) under full load and in two boiler plants (< 100 kW) under different load conditions. Lab analysis will show the thermochemical behavior of torrefied fuels depending on different properties.

The thermochemical behavior of the innovative fuel is examined in comparison to wood pellets as a reference. Experiments based on fixed-bed gasification will enable statements on practical applications (plants < 250 kW).

Chosen biomass supply chains based on torrefaction and non-torrefaction biomass contrary to reference systems are analyzed in technical, economic and ecological terms.

Finally the evaluation of the results will be carried out:

  • Classification of feasibility of the different thermochemical conversion paths
  • Determination of the most promising gasification plants and furnaces
  • Illustration of the market potential of torrefied pellets for existing and new plants at the small plant segment in Germany
  • Writing a road-map-report

Burkhardt GmbH

Trials in a 90 kWth Burkhardt pilot plant will be conducted. In regard to process parameters primarily the gasification temperature and the composition of the syngas as well as the amounts of supplied torrefied biomass, of residues and of syngas will be determined. Additionally the composition of gasification residues will be analyzed, aiming at an energy and mass balancing. To determine relevant parameters the DBFZ will give support e.g. in the identification of hydrocarbons and in the ash analysis. Based on these data and results from the DBFZ essential gasification parameters can be validated and the transferability of the results between the used gasification technologies fixed bed (laboratory gasifier) and floating bed (Burkhardt pilot gasifier) can be verified. Also first information about the capability of long-term operation of the pilot and commercial gasifier will be gathered.

Based on the before-mentioned trials in a laboratory gasifier and a pilot plant, additional trials in a commercial gasifier (180 kWel) will be performed, using chosen torrefied biomass. The main research topic is the long-term operation behavior. To enable a comparison of this commercial gasifier with the laboratory and pilot gasifier, the DBFZ supports the record and analysis of relevant process parameters during long-term operation. In this way the impact of several parameters and the used gasifier technology on transferability can be verified. Besides, recommendations regarding the transfer of results to other currently operating small-scale gasifiers can be developed. Furthermore, long-term related effects on gas cleaning of the generated syngas (especially tar formation) originated by the use of torrefied biomass will be compared with common wood pellets. The main focus lies on the amount and kind of residues (ash and condensate).



  • Gasification
  • Torrefaction
  • Wood pellets

Burkhardt GmbH

  • Gasifier temperature
  • Slag formation
  • Gas power
  • Losses due to fuel feeding (leads to an increased share of fine particles)


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