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In the bio-based economy concept, any biomass should not be used directly for energy purposes without considering the possibility of using it for bioproducts with higher added value. Extractable phytochemicals found in lignocellulosic biomass of perennial industrial crops (PIC) are used in the pharmaceutical, cosmetics, chemical, food and feed industries. Therefore, these compounds should be obtained first, and only the so-called PIC extraction biomass should be used, for example, for the production of bioenergy. An efficient low-energy and environmentally friendly method of extracting phytochemicals from the plant biomass is supercritical carbon dioxide (scCO2) extraction. The aim of the study was to assess the thermophysical properties and chemical composition of 19 types of PIC biomass previously subjected to two types of scCO2 extraction compared to the biomass before extraction. The biomass after pure scCO2 and scCO2/H2O (1 wt%) extraction contained less ash (by 4.9 and 11.3%), carbon (by 3.1 and 7.8%), hydrogen (by 5.8 and 8.9%), nitrogen (by 4.5 and 6.8%), sulfur (by 3.8 and 3.8%), lignin (by 5.4 and 1.1%), hemicellulose (by 14.4%) and more chlorine (by 4.7 and 15.3%) compared to the biomass before extraction. In addition, the biomass after extraction with pure scCO2 contained more cellulose and was characterized by lower moisture content and higher heating value and lower heating value. However, the biomass after scCO2/H2O extraction contained more substances soluble in cold and hot water. Generally, the bark of four short-rotation coppice (SRC) species was characterized by a high content of nitrogen, sulfur, substances soluble in cold and hot water, other soluble substances and at the same time low cellulose content (26–28% d.m.). In turn, the wood of all SRC species was characterized by a high cellulose content (51–56% d.m.). However, all herbaceous crops and grasses contained more chlorine, hemicellulose and generally less lignin compared to the SRC biomass. To assess the practical suitability of the PIC biomass extraction for the production of bioenergy (solid, liquid or gaseous biofuels), further research is needed. [ABSTRACT FROM AUTHOR]

Solid biomass is a promising alternative to traditional energy resources, able to successfully reduce the negative effects of climate change. The structure of energy production from renewable sources shows that solid biofuels have the largest share in Poland and the EU28. Thus, solid biofuels constitute an important and interesting alternative to solid fossil fuels. However, due to its wide variety of origin, logistics and processing technology, the properties and quality of solid biofuels may vary. Therefore, the aim of the study was to determine the thermophysical properties and elemental composition of solid biofuels of agricultural and forestry origin compared to solid fossil fuels. The research material were 20 types of solid fuel, including 16 renewable and 4 fossil fuels obtained from plantations of the University of Warmia and Mazury in Olsztyn and from two heat generation and distribution enterprises (Olsztyn and Grudziądz). The experiment confirmed that selected solid biofuels from agriculture and forestry are a good alternative to fossil fuels like coal in terms of some thermophysical properties and elemental compositions. The content of ash in coal fuels was 3- to16-fold higher than in agricultural and forest origin biofuels. Moreover, the content of sulphur in coal fuels was from 5- to 31-fold higher than in agricultural and forest biofuels. Considering the above, the use of solid biofuels for energy generation may create a less negative effect on the environment than coal fuels. [ABSTRACT FROM AUTHOR]

The energy values of spelt (Triticum spelta) and emmer (T. dicoccon) chaff were determined and compared to wheat and barley straw. The thermophysical parameters (moisture content, lower calorific value, gross calorific value, content of fixed carbon, volatile matter, and ash) and elemental composition (content of C, H, S, N, and O) of spelt and emmer chaff were determined. Spelt and emmer chaff were characterized by higher gross calorific value (18.75 GJ/Mg vs. 18.31 GJ/Mg), higher lower calorific value (16.74 GJ/Mg vs. 16.35 GJ/Mg), noticeably lower ash content (3.79% vs. 6.16%) and lower content of volatile matter (70.3% vs. 74.9%) than wheat and barley straw. Emmer chaff contained noticeably more sulfur (0.148%), nitrogen (2.20%) and hydrogen (7.50%) than both types of straw (0.064%, 0.66% and 5.55% on average, respectively) and spelt chaff (0.071%, 0.80%, and 7.06%, respectively). Despite the fact that the relatively high sulfur content in emmer chaff is not desirable, the results of this study indicate that the chaff of hulled wheat had considerable energy potential and that hulled wheats could be effectively used as renewable sources of energy in the region of their production. [ABSTRACT FROM AUTHOR]