Components of biomass mainly refer to all the organic materials and substances that constitute biomass. They primarily constitute lignocellulosic content (cellulose, hemicellulose, and lignin), followed by proteins, starch and sugars.
A carbohydrate polymer comprises of glucose units. It is mainly found in seeds, tubers, and stems. It is a storage form of plant energy and can be readily broken down into glucose molecules through enzymatic hydrolysis. Glucose, a derivative of starch, can be fermented to produce ethanol or used as a feedstock for industrial purposes.
Proteins are complex macromolecules comprises of amino acids link together and play a crucial role in living organisms’ growth, development and metabolism. It can be use as a feedstock to produce biofuels and other valuable components.
Biomass derived from sugar-rich plants like sugarcane or beets contain sugar derivatives like glucose, fructose and sucrose. These sugars can be extracted and used as raw material for various fermentation processes to produce bioethanol or other chemicals.
Lignocellulosic composition of various Biomasses (Li et al., 2019)
Physicochemical characteristics of biomass
Heating value or calorific value
The heating value of biomass indicates the energy available in the fuel per unit mass (MJ/kg). It represents the amount of heat release when a given quantity of fuel burns completely, besides signifying the energy available for heat transfer.
Calorific content of various biomasses (Clarke & Preto, 2011)
It is the amount of water present in the biomass; and depends on the type of biomass, weather condition, storage and handling. In general, biomass with high moisture content reports reduced calorific content, and vice versa in the case of dried biomass. As a result, freshly harvested biomass has low energy value due to its high moisture content; hence, it needs to be dried before any processing into fuel to enhance its calorific content.
Moisture content in various biomasses (www.vt.tuwien.ac.at/biobib)
Any uncombusted residues during fuel combustion are taken as ash and primarily composed of minerals like calcium, potassium, silica, and trace elements. It is an important parameter to consider because the ash content of the biomass affects its overall combustion efficiency, its performance in heating systems, and its emission characteristics. Moreover, the ash content varies with biomass.
Ash content in various biomasses (Clarke & Preto, 2011)
The carbon content of biomass is around 45%. Higher carbon content leads to higher heating values. However, this value can range from as low as 40% to as high as 60%, depending on the specific composition of the biomass.
Carbon content in various biomasses (AURI, 2005; Preto, 2010)
It is an essential element for growth of plants and serves as a building block of various components of proteins, nucleic acid and other organic materials. In general, biomasses with high nitrogen content are responsible for emitting high nitrogen oxide (NOx) emissions during their combustion; but reduce with decreasing levels of nitrogen content.
Nitrogen content in various biomasses (Clarke & Preto, 2011)
It is always necessary to study this organic sulphur content in biomasses, as they can form sulfur dioxide (SOx) emissions. However, biomass usually has negligible sulfur content; therefore, its combustion does not significantly contribute to any SOx emissions.
Sulfur content in various biomasses (Clarke & Preto, 2011)
Li, H., Wang, L., Ji, Y., Xue, S. and Wang, Z., 2019. Study on the mechanism of gas component release for biomass pyrolysis. In E3S Web of Conferences (Vol. 118, p. 03058). EDP Sciences.
Clarke, S. and Preto, F., 2011. Biomass burn characteristics (pp. 11-033). Guelph, ON, Canada: Ministry of Agriculture, Food and Rural Affairs)
AURI. 2005. Agricultural renewable solid fuels data. Retrieved from Agricultural Utilization Research Institute Fuels Initiative website.
Preto, F., 2010. Properties of the 13 common biomass fuels in Ontario. Natural Resource Canada(NRCan), Ottawa, ON.