Heat and power production from straw (Produktion af kraftvarme fra halm)
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Denmark
1999
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Straw
from grain can be used as energy source in heat and power production.
Process description
The present data
refer to heat and power production at Masnedø
heat and power plant (Denmark) in
1999. The plant is dimensioned to 10 MW electricity
and 23 MJ heat/sec and is primarily fired with
straw (about 40.000 t/year). The main production processes are following:
1)
straw bales (about 0.5 t each, 10-20% water content) are delivered to the plant in trucks
and stored (capacity 1000 t) 2) straw is transported by a crane and conveyor lines to two vertical "snails" where the straw is cut into
pieces 3) the loose straw is transported to the fire chamber through an air
tight channel and burnt 4) heat from the fire is used to
produce steam which is used to produce electricity in a turbine, 5) steam is
condensed and returned to the furnace, 6) condensation heat is transferred
to a heat accumulation tank 7) heat is distributed to district
heating network when needed. The
plant is equipped with electrical filter for reduction of fly ash emission but
no SOx and NOx filtration system has been implemented. Slag is returned to agricultural land and used as fertilizer
(nutrient content, see below). Fly ash is
deposited (due to a high content of heavy metals). The plant's production is
determined by heat demand. Production is determined by heat demand.
Data collection and treatment
Data on straw, water and oil consumption and data
on heat/electricity production and slag/ash generation have been derived from Masnedø
heat and power plant's green account 2002. Data are derived from 1999 where input from other biomass than straw was relatively low (10%
in terms of mass). As an
approximation, all biomass entering the plant has been considered as straw.
Data on emissions to air have been determined from emission factors (Energistatistik,
2002 and Gasteknisk Center, 2003).
Technical scope
All processes related to heat and power production (including
administration and local wastewater treatment) are included. Use and disposal
of chemicals has not been included. Inputs and output of
seawater (for cooling purposes) has not been considered. Solid waste
generation (except slag and ash generation) has been ignored. Emissions of VOC
and heavy metals to air have been ignored due to lack of data. The plant is
established in 1996 and represents modern technology.
Representativity
All
straw used for heat and power production was fired at de-central plants like
Masnedø in 1999. However, central units are currently being installed and an increasing ratio of straw is fired in central plants (about
one forth in 2004).
Masnedø
heat an power plant is a medium sized de-central plant which provides a reasonable
representation straw/biomass fires plants in Denmark. Central plants are
installed with desulfurication and denoxification units and the emissions of
SOx and NOx per produced units of heat and power are supposedly somewhat lower
at these types of plants (no data available at the moment).
Data
on air emissions are derived from a broad spectrum of plants in Denmark
(Gasteknisk Center, 2003)
and are representative for production in Demark at decentral plants.
Validation
Data
on emissions to are validated (Gasteknisk
Center, 2003). Other data are
not.
Inputs and outputs
Inputs and outputs associated with heat and power production from straw (10-20% water content) Data
are provided per
ton
of
straw applied.
1) Phosphor (P): 0.8 -2.1% (w/w), sulphur
(S): 0.1 - 0.7% (w/w) calcium (Ca): 6-13% (w/w) nitrogen: 0.05 - 0.08 (w/w).
Videncenter for halm og flisfyring (1999).
Location
in database: Waste
Treatment/others/Energy production from straw |
References
Energistatistik (2002): Energistyrelsen.
Gasteknisk Center (2003):
"Miljøforhold kortlagt decentral fraftvarme". Nyhedsbrev fra Dansk
Gasteknisk Center (August).
Masnedø
Kraftvarmeværk, Green
account 2002 (in
Danish).
Videncenter
for halm og flisfyring
(1999): Halmasker, kemisk sammensætning (videblad nr. 146).
Videncenter
for halm og flisfyring
(1998): Halm til
energiformål - Teknik, miljø og økonomi.
Administrative information
Data URL: http://www.lcafood.dk/processes/energyconversion/heatandpowerfromstraw.htm
Version no.: 1.00
Author: Per
H. Nielsen, The Institute for Product
Development
Data entry:
Data have been entered in this format by Per H. Nielsen.
Data completed: February
2004.
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