76
3 Advanced Technologies (Biological and Thermochemical) …
The project targets to process 500–2000 lb/h of grass straw for syngas production. As
planned, the produced syngas after cleaning will be used to generate electricity using
a 300 KW reciprocating engine/generator. It is also planning to convert the syngas
into liquid fuels, and it was estimated to produce 60 gallons of fuel from a ton of
straw. In Denmark, a 1.5 MW e demonstration plant using wood chips as the feedstock
in an updraft gasifier began operating in 1994 to generate syngas for district heating
purposes. They started to generate electricity since 2005 by burning the produced
syngas in two gas engines. A commercial plant producing 3 MW e electricity from
gasification of wood chips is planned by the company. A demonstration plant was
commissioned in 2006 in France for gasification of wood waste and distillery residue
in a “pseudo updraft” gasifier. The produced syngas is cleaned and burned to produce
1 MW e of power. There is also another 12.5 MW e commercial-scale project under
development. At the Lahden Lämpövomia Oy’s Kymijärvi power plant in Lahti,
Finland, an air-blown circulating bed gasifier has been used since 2002 to gasify
a variety of biomass/wastes including paper and textiles, wood and peat, shredded
tires, plastics and municipal solid waste. The producer gas is then co-fired with coal
to produce electricity and district heat in a maximum capacity of 167 MW e . A gasification plant in Austria has been operational since 2008, using wood as the feedstock
in a circulating fluidized-bed gasifier. The heat produced from the gasifier is recovered using the Organic Rankine Cycle to generate electricity, and bio-methane is
produced as the main product from the gasifier [65].
3.2 Biochemical Conversion Technologies
Biochemcial conversion methods are the processes that use microorganisms and
enzymes in addition to heat and other chemicals to breakdown the biomass into
gaseous or liquid fuels. The most popular biochemical conversion methods are
anaerobic digestion and fermentation.
3.2.1 Anaerobic Digestion
Anaerobic Digestion (AD) is a biological process for stabilization of organic waste
in the absence of air resulting in the reduction of Volatile Solids (VS) and production
of biogas (mainly methane) and digestate (as the by-product). Biogas can be used
as a gaseous fuel to produce electricity and heat (co-generation) in a gas turbine or
engine or in a boiler or furnace, or cleaned and used as a natural gas substitute [66].
Digestate can be processed to produce liquor and fibrous material. The liquor can
be used as fertilizer due to high levels of nutrients, while the fibrous material can be
used as a soil conditioner as it has a low level of nutrients [67]. Organic waste from
various sources such as MSW, animal manure, poultry litter, food waste, sewage
3 Advanced Technologies (Biological and Thermochemical) …
The project targets to process 500–2000 lb/h of grass straw for syngas production. As
planned, the produced syngas after cleaning will be used to generate electricity using
a 300 KW reciprocating engine/generator. It is also planning to convert the syngas
into liquid fuels, and it was estimated to produce 60 gallons of fuel from a ton of
straw. In Denmark, a 1.5 MW e demonstration plant using wood chips as the feedstock
in an updraft gasifier began operating in 1994 to generate syngas for district heating
purposes. They started to generate electricity since 2005 by burning the produced
syngas in two gas engines. A commercial plant producing 3 MW e electricity from
gasification of wood chips is planned by the company. A demonstration plant was
commissioned in 2006 in France for gasification of wood waste and distillery residue
in a “pseudo updraft” gasifier. The produced syngas is cleaned and burned to produce
1 MW e of power. There is also another 12.5 MW e commercial-scale project under
development. At the Lahden Lämpövomia Oy’s Kymijärvi power plant in Lahti,
Finland, an air-blown circulating bed gasifier has been used since 2002 to gasify
a variety of biomass/wastes including paper and textiles, wood and peat, shredded
tires, plastics and municipal solid waste. The producer gas is then co-fired with coal
to produce electricity and district heat in a maximum capacity of 167 MW e . A gasification plant in Austria has been operational since 2008, using wood as the feedstock
in a circulating fluidized-bed gasifier. The heat produced from the gasifier is recovered using the Organic Rankine Cycle to generate electricity, and bio-methane is
produced as the main product from the gasifier [65].
3.2 Biochemical Conversion Technologies
Biochemcial conversion methods are the processes that use microorganisms and
enzymes in addition to heat and other chemicals to breakdown the biomass into
gaseous or liquid fuels. The most popular biochemical conversion methods are
anaerobic digestion and fermentation.
3.2.1 Anaerobic Digestion
Anaerobic Digestion (AD) is a biological process for stabilization of organic waste
in the absence of air resulting in the reduction of Volatile Solids (VS) and production
of biogas (mainly methane) and digestate (as the by-product). Biogas can be used
as a gaseous fuel to produce electricity and heat (co-generation) in a gas turbine or
engine or in a boiler or furnace, or cleaned and used as a natural gas substitute [66].
Digestate can be processed to produce liquor and fibrous material. The liquor can
be used as fertilizer due to high levels of nutrients, while the fibrous material can be
used as a soil conditioner as it has a low level of nutrients [67]. Organic waste from
various sources such as MSW, animal manure, poultry litter, food waste, sewage