Details

Title:

Combined Fermentation and Gasification of Biomass in a New Concept for Decentralised Power Generation

Author(s):

Methling, T., Armbrust, N., Speidel, M., Poboss, N., Zieba, M., Scheffknecht, G., Sterr, Y., Schliessmann, U., Braun-Unkhoff, M., Riedel, U., Kraaij, G., Wörner, A.

Document(s):

Abstract:

Currently, it is discussed to which extent future energy demands can be satisfied by biomass and by­products, without any concurrence to food production. Whereas fossil fuels are converted to energy in large scale power plants with high electric efficiencies, biomass feedstock exists widespread and in small amounts and is usually converted in small scale power generation. To keep up with future energy demands, it is essential to develop decentralised biomass conversion processes with high electrical efficiencies. One option, to meet these requirements is the proposed concept of combined fermentation and gasification with subsequent utilisation of the product gases in a hybrid power plant. In our concept, wet biomass is fermented and the dried residues are gasified in a two­stage fluidised bed gasifier, with CO2 separation. The biogas and syngas are fed into a solid oxide fuel cell (SOFC) and the fuel cell off­gas – still containing combustible – is burned in a gas turbine (GT). The aim of the present work is to give a detailed overview on the overall concept with regard to the coupling of the sub­processes. The specific fermentation and gasification processes are investigated. The compositions of the product gases are determined experimentally. Selected combustion properties of the SOFC off­gas are characterised to enable a more efficient design of fuel flexible combustion chambers for reliable GT operation at low emission levels. Therefore, laminar flame speeds are simulated with several chemical kinetic reaction models and ignition delay times are discussed. The simulation of the process chain predicts a high overall electric efficiency of 42 %. Therefore, the concept of the present work is considered a promising approach for a future decentralised power generation using biomass.

Keywords:

fermentation, gasification, sewage sludge, fuel cell, gas turbine, decentralised

Topic:

R&D on Biomass Conversion Technologies for Heating, Electricity and Chemicals

Subtopic:

Gasification for power, CHP and polygeneration

Event:

21st European Biomass Conference and Exhibition

Session:

2CV.3.20

Pages:

808 - 813

ISBN:

978-88-89407-53-0

Paper DOI:

10.5071/21stEUBCE2013-2CV.3.20

Price:

FREE