Combustion properties of Miscanthus x giganteus biomass - Optimization of harvest time

The importance of energy crops as replacement for fossil fuels is constantly increasing. Miscanthus x giganteus is a perennial grass which in the past ten years emerged as one of the most interesting bioenergy crops. Additionally to a number of benefits, the characteristic of Miscanthus x giganteus is that it can be harvested during the whole period of dormant vegetation. Although the lignocellulosic biomass of Miscanthus x giganteus can be used for production of second-generation bioethanol, currently it is mostly utilized as raw material for the production of electrical and/or heat energy by direct combustion process. The aim of this paper is to optimize the harvest time of Miscanthus x giganteus grass, which is based on its combustion properties of harvested biomass. Based on the analyses of the biomass from three different harvest times established are significant variations in biomass moisture content, carbon hydrogen, oxygen, nitrogen and sulphur content. All other analysed parameters are in accordance with or within expected differences from the values stated in the literature and/or CEN/TS 14961 norm for solid fuels. Delayed harvest enhances the quality of biomass in terms of combustion process, primarily through lowering moisture content.