Evaluation of the Processing of Multi-Crop Plants into Pelletized Biofuel and Its Use for Energy Conversion

Multi-crop plants (fibrous hemp, maize, and faba bean) can potentially be an alternative to wood biomass pellets, but there is no detailed knowledge to support the suitability of this biomass for solid biofuel production. The aim of this study is to analyze and justify the suitability of multi-crop plant biomass for the production of biofuel pellets and to assess the environmental impact of burning them. This paper presents studies of physical-mechanical, thermal, and chemical characteristics of biofuel pellets from multi-crop plants and emissions during their combustion under laboratory conditions. The main parameters of the produced pellets were determined according to international standards, which are detailed in the methodology part. The length of the produced pellets ranged from 17.6 to 26.6 mm, and the diameter was about 6 mm. The density of wet pellets varied from 1077.67 to 1249.78 kg m−3. The amount of ash in the pellets varied from 5.75% to 8.02%. Determined lower calorific value of all pellets was close to 17.1 MJ kg−1. The lowest CO and CxHy emissions were determined when burning MIX2-1 pellets (biomass of the binary crop); their values were 572 and 29 ppm, respectively. The lowest content of CO2 was determined when burning S-Mz pellets (mono crop biomass), and it was 3.5%. The lowest NOx emissions were also determined when burning the pellets of this sample, with a value of 124 ppm. Research results show that multi-crop plants are a suitable raw material for the production of solid biofuel, the burning of which does not cause negative consequences for the environment