Page 378 - Refining Biomass Residues for Sustainable Energy and Bioproducts

342 Refining Biomass Residues for Sustainable Energy and Bioproducts

such as sodium, potassium, calcium, alumina, silica, and iron, which describes its
behavior of forming deposits in the boiler or gasifiers.
Volatile matter is the amount of matter except moisture that is liberated when
biomass is heated at high temperature in absence of air. It is the additive of con-
densable vapors and noncondensable gases. Higher amount of volatile matter sig-
nifies higher amount of liquid and gaseous biofuel. It is determined according to
the ASTM E872-82 (2013) where biomass sample is put inside the crucible with lid
to keep away from the air contact and then it is heated in a muffle furnace for devo-

latilization at temperature of 950 C for 7 min. After cooling in desiccators the
weight loss is the amount of volatile matter.
Fixed carbon is the amount the solid combustible residue that is left after elimi-
nating the moisture, ash, and volatile matter. It is calculated based on the following
equation

Fixed carbon ð%Þ 5 100 ðmoisture content 1 ash content 1 volatile matterÞ

15.3.2.2 Ultimate analysis
The ultimate analysis gives more widespread results as compared to the proximate
analysis. It determines the amount of carbon, hydrogen, nitrogen, and sulfur content
in the biomass. This analysis is performed using CHNS analyzer on a dry basis.
The amount of oxygen is calculated by subtracting the total amount of abovemen-
tioned elements from 100. The typical amount of carbon and hydrogen in agricul-
tural wastes varies from 40 to 50 and 4 to 6 wt.%, respectively.

15.3.2.3 Heating value

Heating value (calorific value) of biomass refers to the energy content, that is, the
amount of energy stored in the unit mass of biomass and it is expressed as
Megajoule/kilogram (MJ/kg). Basically, there are two types of heating value. One
is lower heating value (LHV) and the other is high heating value (HHV). LHV is
the amount of heat stored in the biomass excluding the latent heat of vaporization
of water, whereas HHV is additive of LHV and latent heat of vaporization of water.
The standard method and instrument generally used for determination of HHV are
ASTM D5865-13 and oxygen bomb calorimeter (Miller et al., 2010). Table 15.1
presents the proximate analysis, ultimate analysis, and HHV of some agricultural
wastes.

15.3.2.4 Compositional analysis
Lignocellulosic agricultural biomass comprises mainly three components, that is,
hemicelluloses, cellulose, and lignin. The quantity of each component can be deter-
mined by using Van Soest’s method, National Renewable Energy Protocol method,
or Technical Association of the Pulp and Paper Industry method. The amount of the
three components varies depending upon the nature and part of the biomass being