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| Sugar processing |
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Energy |
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What forms of energy does
a sugar factory need?
Thermal and electrical energy are needed to process sugar. Both
forms of energy are obtained in a combined heat and power plant.
Thermal energy is needed to turn the water into steam. The water
is heated using waste heat flows. |
How much energy does a sugar
factory need?
The energy requirement of a sugar factory depends on the number
of beet processed per day: At 10,000 tonnes of sugar beet per
day, the boiler will require about 1,750 MWh and drying the
slices 750.5 MWh. |
Is heavy oil or gas used
to produce steam?
The factories can use both fuels in a bivalent firing process.
The fuel that is used will depend on availability and market
price. |
Why is raw lignite also
used?
Raw lignite is a local German fuel, whose use depends on availability
and market price, as in the case of other fuels. Modern processes
ensure that the process is environmentally friendly. |
What is the contribution
of electrical energy?
A works processing 10,000 tonnes of sugar beet per day on average
will require about 250 MWh of electrical energy. The electrical
energy required is generated by a combined heat and power plant
located in the works themselves. Electricity is normally only
bought in if there are malfunctions in the power plant or turbine. |
Is waste heat used?
Thermal energy is generated in a sugar factory’s own combined
heat and power plant. The factory actually only requires heat
at one point in the process: the first stage of the evaporation
unit. The steam resulting from evaporation at this stage is
re-cycled for evaporation and heating purposes. This principle
is repeated 5 or 6 times, which means that about 75 % of a sugar
factory’s energy requirement is covered by waste heat.
Heat flows (condensates) leave the factory at a temperature
of between 30 °C and 50 °C. The utilisation of the heat
flows is subject to technical and economic limits. |
Wouldn’t it be possible
to also obtain energy from the steam that is released into the
open air at a number of points?
These are waste gases that have been mixed with a large amount
of steam. The temperature of the waste gases is less than 100
°C. The condensation temperature of steam is less than 70
°C. Significant amounts of thermal energy can only be recovered
below this temperature. The technical cost of such a process
would be very high, however. There are therefore technical and
economic limits to the use of these heat flows. |
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What comes out of the drying
tower?
Mainly steam, which results from the drying of the exhausted
slices of sugar beet. |
Why does the steam from
the chimney smell?
Because it contains traces of organic substances that were contained
in the beet itself or have been formed during processing. |
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