Assessment of the quality of secondary production from different agricultural crops used as primary material for densified solid biofuels

Abstract

The quality of densified solid biofuels is directly influenced by the biomass characteristics used as feedstock. Under the conditions of the Republic of Moldova, the main source of raw material used in the production of briquettes and pellets is represented by agricultural residues and those from the food industry. For this reason, it is important to know the qualitative characteristics of these residues. The purpose of this study is to highlight the main qualitative parameters of agricultural residues used as energy sources specific for the Republic of Moldova. The issue of research refers to the estimation of the possibilities of using indigenous agricultural residues as a raw material for the production of densified solid biofuels with ENPlus 3 characteristics. The investigative methodology is based on a complex study, organized and realized in the Solid Biofuels Laboratory of the State Agrarian University of Moldova. The paper presents the results of the research regarding the estimation of the calorific value, the moisture content, the ash content and the chemical analysis of the main agricultural residues from the agrarian sector depending on their origin and specificity, emphasizing on herbaceous, arboreal and vines residues. The study showed that only about 10% of the residues from agricultural activities can be used directly to produce bio briquettes and pellets with qualitative indicators according to the requirements of ENPlus 3. It should be noted that practically, all agricultural and vineyard residues can be used as a raw material to the production of ENPlus certified densified solid biofuels, and herbaceous residues can only be used in mixtures with other types of vegetable biomass or require pre-treatment before densification, for example, by torrefaction.