DEMONSTRATION OF HANDLING AND LOGISTICS OF TORREFIED PELLETS

摘要

In this study torrefaction was demonstrated at a Torrec Ltd. pilot plant located in Mikkeli, easternrnFinland. The pilot plant with a nominal capacity of 10,000 tonnes/year began operation in August 2014. Therntorrefaction solution is based on a vertical reactor, where biomass material flows by gravity without drives orrnactuators and torrefaction happens by steam inertization and accurate process control. Steam is supplied from thernlocal biomass CHP plant next to the pilot plant. The product quality of torrefied pellets will be analysed by testingrnalternative local woody biomass sources, such as forest chips made from coniferous trees (spruce, pine) and broadleafrn(birch), as well as by-products such as bark. Energy density, moisture and ash content, and alkalis will be verified.rnAdditionally, the durability of pellets and grindability will be verified by means of laboratory tests. The potentialrnFinnish customers are CHP plants aiming to replace coal with pellets. In 2013 coal use was 31.2 TWh, whererncondensing was 15.3 TWh, CHP 14.2 TWh, and separate heat 1.6 TWh in Finland. If half of the current coal use inrnCHP were replaced by biocoal, then Finnish potential bio-coal markets would be 7 TWh or 1.2 million tonnes ofrnpellets/year. Aided by the results of this demonstration study and modelling of logistics it is possible to evaluate therncompetitiveness of torrefied pellets based on the local circumstances.