Page 352 - Solid Waste Analysis and Minimization a Systems Approach

330 AGRICULTURAL, FORESTRY, AND FISHING APPLICATIONS

Most commonly, biomass refers to plant matter grown for use as biofuel, but it also
includes plant or animal matter used for production of fibers, chemicals or heat.
Biomass may also include biodegradable wastes that can be burned as fuel.
Biomass is grown from several plants, including miscanthus, switch grass, hemp,
corn, poplar, willow, sugarcane, and palm oil. The particular plant used is usually not
very important to the end products, but it does affect the processing of the raw material.
Production of biomass is a growing industry as interest in sustainable fuel sources is
growing.
Biomass that is not simply burned as fuel may be processed in other ways such as
corn. Low-tech biomass processes are

■ Composting (to make soil conditioners and fertilizers)
■ Anaerobic digestion (decaying biomass to produce methane gas and sludge as a
fertilizer)
■ Fermentation and distillation (both produce ethyl alcohol)

More-high-tech processes are

■ Pyrolysis (heating organic wastes in the absence of air to produce gas and char;
both are combustible).
■ Hydro-gasification (produces methane and ethane).
■ Hydrogenation (converts biomass to oil using carbon monoxide and steam under
high pressures and temperatures).
■ Destructive distillation (produces methyl alcohol from high-cellulose organic wastes).
■ Acid hydrolysis (treatment of wood wastes to produce sugars, which can be distilled).
■ Burning biomass, or the fuel products produced from it, may be used for heat or
electricity production.

Other uses of biomass besides fuel and compost include

■ Building materials
■ Biodegradable plastics and paper (using cellulose fibers)

Most biomass is converted to energy the same way it always has been—by burning
it. The heat can be used directly for heating buildings, crop drying, dairy operations,
and industrial processes. It can also be used to produce steam and generate electricity.
For example, many electric generators and businesses burn biomass by itself or with
other fuels in conventional power plants.
Biomass can also be converted into liquids or gases to produce electricity or trans-
portation fuels. Ethanol is typically produced through fermentation and distillation, in
a process much like that used to make beer. Soybean and canola oils can be chemically
converted into a liquid fuel called biodiesel. These fuels can be used in conventional
engines with little, if any, modification.