Valorisation of low grade Biomass to substitute fossil Fuels in a thermal Power Plant

Published 2010

Citation: Kern S, Halwachs M, Hofbauer H, Kampichler G. Valorisation of low grade Biomass to substitute fossil Fuels in a thermal Power Plant, WasteEng 2010, 17th-19th of May 2010, Peking, China.

Abstract

Minimizing carbon dioxide emissions whereas keeping up the high living standard of today is only possible by increasing the efficiency of energy consumption and the change to a mix of renewable fuels. Huge amounts of unused biomass in terms of agricultural residues like straw, that is a cheap and local feedstock, are often available. But as a reason of the high amount of corrosive ash elements (K, Cl, S), the residues are not suitable for co-firing in a thermal power plant. Therefore the feedstock is converted by low temperature pyrolysis into pyrolysis gases and charcoal. The aim of this work is to obtain fundamentals for an advanced pyrolysis model approach by the results of the pilot plant for co-firing the pyrolysis gases in a thermal power plant. A 3 MW pyrolysis pilot plant is being operated since 2008. For the process, an externally heated rotary kiln reactor with a design fuel power of 3 MW is used. Several mass and energy balances have been calculated based on measured plant data for different operating points of the pilot plant. The high amount of pyrolysis oil in the gas has positive effects to the heating value of the pyrolysis gases. As a reason of that, cold gas efficiencies of more than 70 % are possible. Based on these results, a scale up to a next scale pyrolysis reactor with a capacity of 30 MWth fuel input is currently investigated.