Chemical Composition of Biomass

The simplest way of describing the ehemieal nature of biomass is by its elemental composition. For marine phytoplankton as primary producers a relationship was found to the nutrients available in seawater whieh led to the definition of the Redfield ratio as C N P = 106 16 1 (Redfield et al. 1963). Derived from this is an average molecular formula of phytoplankton organic matter related to the general process of phytosynthesis (of which the reverse signifies remineralization)  

Nueleie aeids, as ribonueleie aeids (RNA) or desoxy-ribonueleie aeids (DNA), are biologieal maeromolecules eany ing genetie information. They eonsist of a regular sequenee of phosphate, sugar (pentose) and a small variety of base units, i.e. nitrogen-bearing heterocyclie 

Lignin is a structural component of plant tissues where it ocems as a three-dimensional network together with cellulose. Lignin is a macromolecular condensation product of three different propenyl (C3-substituted) phenols (one type of few biogenic aromatic compoimds). It is preserved, even dining transport from land to ocean and during sedimentation to the seafloor where it occurs predominantly in hiunic organic matter of deltaic environments. 

Cutin and suberin are lipid biopolymers of variable composition which are part of the protective outer coatings of all higher plants. Chemically, cutin and suberin are closely related polyesters composed of long-chain fatty and hydroxy fatty acid monomers. Both types of biopolymers represent labile, easily metabolizable terrigenous organic matter because they are sensitive to hydrolysis. After sedimentation, they have only a moderate preservation potential. 

Cjj) in contrast to the acids and alcohols which show an even-carbon-number predominance. 

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Yields of the different pyrolysis products (i.e. char, bio-oil, and gases) are dependent on the chemical composition of biomass. Biomass with high lignin content produces more char compared to biomass with lower content [20], Furthermore, biomass with high alkali and alkali earth metal concentrations generates less bio-oil and instead more char and gases [14, 15, 21]. Prior to pyrolysis, it is beneficial to dry the biomass to less than 10 wt% moisture in order to minimize the water content in the bio-oil [14],... 

CHEMICAL COMPOSITION OF BIOMASS FAST PYROL YSIS UQUID... 

The chemical composition of biomass with respect to carbon, hydrogen and oxygen can be approximated by the formula C6H9O4, that is biomass contains a little less... 

The chemical composition of biomass materials is generally discussed in terms of cell wall polysaccharides (cellulose and hemicelluloses), phenolics (lignin and polyphenols), extractives, and ash content. Wood normally contains small amounts of ash (1 percent) and various quantities of extractives... 

VassUev SV, Baxter D, Andersen LK, VassUeva CG. (2010). An overview of the chemical composition of biomass. Fuel, 89(5), 913-933. 

Alen R. Structure and chemical composition of biomass feedstocks. In Alen R, editor. Biorefining forest resources. Helsinki (Finland) Paper Engineers Association/Paperi ja Puu 2011.p. 17—54. 

For anabolic reactions, which result in the production of new cells, it is important to know the approximate chemical composition of the biomass. The bacterial protoplasm comprises 75 to 80% water. The solid material is composed of several complex organic molecules, such as proteins, carbohydrates, and DNA. The mean composition of these molecules can be approximated by a relatively simple empirical formula, C60H87O23N12P, or in an even more simple form as C5H7O2N10.Numerous other elements such as sulfur, sodium, potassium, calcium, magnesium,... 

Complex pyrolysis chemistry takes place in the conversion system of any conventional solid-fuel combustion system. The pyrolytic properties of biomass are controlled by the chemical composition of its major components, namely cellulose, hemicellulose, and lignin. Pyrolysis of these biopolymers proceeds through a series of complex, concurrent and consecutive reactions and provides a variety of products which can be divided into char, volatile (non-condensible) organic compounds (VOC), condensible organic compounds (tar), and permanent gases (water vapour, nitrogen oxides, carbon dioxide). The pyrolysis products should finally be completely oxidised in the combustion system (Figure 14). Emission problems arise as a consequence of bad control over the combustion system. 

Particle physical properties typically change under the impact of smoke plume but these changes may not be specific for the wildfire smoke. In addition to biomass burning, particle mass or number concentration can increase due to the biogenic or other anthropogenic sources, e.g., traffic or industrial emissions. Chemical composition of particles is more unique to particle source, however, particles with similar chemistry can have different origin. Physical and chemical properties of the LRT biomass burning particles observed in Northern Europe are discussed below. Physical properties and the chemical components measured from the smoke particles are summarized in Table 2. The measurements of PM mass concentrations are excluded from Table 2 as nearly all the studies had some measurements of particle mass. 

After release from fires, organic and some inorganic components undergo rapid or more delayed chemical transformation in the atmosphere. The physical properties as well as chemical composition of smoke particles may alter on the way from the source areas (biomass burning areas) to the measurement sites in Northern Europe. There are several reasons why particle properties change. Chemical components can, e.g., become oxidized or substituted in particles, but also the condensation of secondary material onto the LRT particles during the transport changes the particle properties. 

Saarikoski S, Sillanpaa M, Sofiev M, Timonen H, Saamio K, Teinila K, Karppinen A, Kukkonen J, Hillamo R (2007) Chemical composition of aerosols during a major biomass burning episode over northern Europe in spring 2006 experimental and modelling assessments. Atmos Environ 41 3577-3589... 

Anttila P, Makkonen U, Hellen H, Kyllonen K, Leppanen S, Saari H, Hakola H (2008) Impact of the open biomass fires in spring and summer of 2006 on the chemical composition of background air in south-eastern Finland. Atmos Environ 42 6472-6486... 

Table 1.4 General chemical compositions of selected biomass components and petroleum (Pun et ah, 2007)...

Zagreba ED, Savenkov V, Ginovska M (1990) IR-spectrophotometric control of chemical composition of microbial biomass. In Microbial conversion - fundamental aspects. Zinatne, Riga, Latvia, p 139... 

Fig- 33.14. Chemical composition of five commercial biomass feedstocks showing the variance in number and concentration of constituents. 

Black carbon is a general denomination for materials such as soot, graphitic carbon and carbon black. The incomplete combustion of fossil fuels and biomass releases enormous quantities of these materials into the atmosphere, about 13Tgyear 1 on a global basis [55]. Both natural and anthropogenic processes contribute to this input. The chemical composition of the carbonaceous particles in the atmosphere is highly variable, as it depends on their formation process and ageing. 

Schneider, G. (1988). Chemical composition and biomass parameters of the common jellyfish Hwrc/w aurita. Helgolaender Meeresuntersuchungen 42, 319—327. 

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