Evaluating potential of organic carbon production from fibre hemp biomass

Abstract

Fibre hemp (Cannabis sativa L.) is a multifunctional plant. All parts of the plant can be usefully used in the production of various products. It is very unfortunate, but most of the fibre hemp biomass, which remains after harvesting seeds and/or inflorescences, is not used in Lithuania. It is sealed or otherwise disposed of. Fibre hemp biomass can be used to produce organic carbon (biochar). Recently, interest in organic carbon and its use for fertilization has grown significantly. Organic carbon is said to be an effective tool in cultivating soil quality, reducing its degradation and the intensity of gas emissions from the soil. Organic carbon is produced by burning biomass in an anaerobic environment. Its yield and quality depend on many factors, of which the properties of the raw material used and the heating temperature are one of the most important. The paper investigates the transformation of fibre hemp biomass into organic carbon. Differences in the conversion of different morphological parts of the plant: stem, fibre, chaff, leaves and husk are analyzed. It was found that the highest yield of organic carbon is typical for leaves (47.9%) and the lowest for fibre (30.2%). By increasing the heating temperature from 400 °C and 800 °C, the yield of organic carbon from fibre hemp biomass decreased to 26.7 - 35.2%. The conversion of fibre hemp biomass to organic carbon also had a significant effect on the ash content and calorific value of the raw material: the ash content of fibre hemp biochar increased on average 2.68 times and the calorific value 1.82 times.