Advantages and disadvantages of composition and properties of biomass in comparison with coal: An overview

Abstract

Abstract An extended overview of the advantages and disadvantages of biomass composition and properties for biofuel application was conducted based on reference peer-reviewed data plus own investigations. Initially, some general considerations and comparisons about composition and properties of biomass and coal as the most popular solid fuel are addressed. Then, some of the major advantages related to the composition and properties of biomass and/or biomass ash (BA) are discussed. They include: (1) high values of volatile matter, H, structural organic components, extractives and reactivity of biomass, water-soluble nutrient elements and alkaline-earth elements in biomass and BA, and pH of BA; and (2) low values of C, fixed C, ash, N, S, Si and initial ignition and combustion temperatures of biomass, and low contents of many trace elements including hazardous ones in biomass and BA. Further, some of the major disadvantages connected with the composition and properties of biomass and/or BA are described. They comprise: (1) high values of moisture and O in biomass, water-soluble fraction, alkaline and halogen elements, and some hazardous trace elements in biomass and BA; (2) low values of energy density (bulk density and calorific value), pH and ash-fusion temperatures of biomass, and bulk density and size of BA; (3) highly variable composition and properties of biomass and BA; and (4) indefinite availability of sustainable biomass resources for production of biofuels. Finally, a discussion about the availability of sustainable biomass resources for production of biofuels and biochemicals is given. It was found that the disadvantages of biomass for biofuel and biochemical applications prevail over the advantages; however, the major environmental, economic and social benefits appear to compensate the technological and other barriers caused by the unfavourable composition and properties of biomass.