Long-term monitoring of the parameters of fuel wooden residues

Abstract

Due to European Union policy aimed at limiting the use of fossil fuels for the production of electricity and heat, there are many of producers looking for suitable substitutes. In 2022 in the Czech Republic coal-fired heating and power plants were almost 47.5% of the energy mix. One of the possibilities is the replacement of coal with wood chips or wood residues from the forest harvesting. But parameters of this material are fluctuating. The article presents the results of the analysis of 403 samples representing deliveries of wood residues with a total weight of 17,473 t over a period of two years. Monitored parameters were moisture and ash content, LHV and HHV. The average values were 36.02 % of moisture content, 2.28 % of ash content, 11.1 MJ·kg-1 LHV and 12.66 MJ·kg-1 HHV. There is an influence of the year period when the wood residues with better LHV were supplied during the summer months. There are some correlations between a moisture content and LHV as well as ash content and HHV. The sample with the highest moisture content (73.58%) had the lowest LHV (3.34 MJ·kg-1). The sample with the highest ash content (18.35%) had the lowest HHV (7.07 MJ·kg-1). In a few of supply were higher content of stones, asphalt or uncrushed parts of the tree which caused problems on heating plant technology.