BIOMASS COMPOSITION, PROPERTIES, AND CHARACTERIZATION - Biomass as a Sustainable Energy Source for the Future - page 38

TABLE 2.1 Physical properties of solid biomass and their possible effects in processing
Physical property

Effect

Bulk density Logistics (storage, transportation, handling)
Electrical conductivity Microwave processing, particle cleaning via electrostatic
precipitation (ash), or fine particulate matter repulsion by plants,
e.g., sea buckthorn (tinyurl.com/luyld2g)

Hygroscopy Logistics (storage, transportation, handling)

Particle density a

Conversion processes (e.g., segregation)

Particle porosity a Formation of fines in processing, intraparticle heat and mass transfer

impacted and so conversion

Particle shape
(distribution)

Storage behavior (dimension/shape of a heap, bridging in bunkers,
self-ignition), transportation (conveying) characteristics, mass and
heat transfer behavior in conversion processes

Particle size
(distribution)

Storage behavior (dimension/shape of a heap, bridging in bunkers,
self-ignition), transportation (conveying) characteristics, mass and
heat transfer behavior in conversion processes

Thermal conductivity Physicochemical processing (heat transfer)

a

These properties are partly linked to each other.

TABLE 2.2 Elements in solid biofuels and their possible main effects in energy
conversion processes

Element Effect

C, carbon Heating value, possible emission of CO

H, hydrogen Heating value

O, oxygen Heating value (negatively impacting)

N, nitrogen Emission of NO, NO 2 (together termed NO x ), and N 2 O

Cl, chlorine Emission of HCl and polychlorinated dibenzo-p-dioxin/furan (PCDD/F),

causing corrosion and catalyst poisoning

S, sulfur Emission of SO 2 ,SO 3 (both named SO x ), causing corrosion and catalyst

poisoning

F, fluor Emission of HF, causing corrosion

K, potassium Corrosion, ash melting, ash utilization, aerosol formation

Na, sodium Corrosion, ash melting, ash utilization, aerosol formation

Mg, magnesium Ash melting, ash utilization, deposits formation

Ca, calcium Ash melting, ash utilization, deposits formation

P, phosphorus Ash utilization, deposits formation

Trace elements Emissions, ash utilization, aerosol formation

of oxygen, which decreases with aging of the fuel. Coal and biomass have similar
ancestors, and fossil fuels in general could be marked as very old biomass. The proc-
ess of coalification starts when plant matter dies and soil covers it; then long-term
(simultaneous) effects of heat, pressure, and microbial action cause the material to
be deprived from oxygen and hydrogen so that it is gradually enriched in carbon.