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Alcohol, brewery
and bioethanol plants waste are different by their properties but for
their recycling one technology is used.
Alcohol plant waste
product is distillery slop, manly from corn. Also
alcohol plants use wheat, rye or grain mixture. Distillery slop
humidity is 88-94%.
Brewer’s grains are
brewery plant waste product, which is
mass after brewing and filtration of barley wort. Brewer’s
grain is thicker then distillery slops and has 78-80% humidity. O
The
brewery plant waste product can be recycled in biogas plant, such as
fermentation sediment and fermentation yeast. Bioethanol plants have
the same waste product as alcohol plants do, but
their quantity 5-10 times more that requires a lot of energy for
recycling.
The main advantage
of biogas plant in comparison with other recycling
systems is that biogas plant doesn’t consume energy but
produces it. Usually waste products quantity is sufficient to cover
company demand electricity and heat. When planning and building new brewery plant with
biogas plant as a part of it,
considerable investment costs savings are possible. As there is no need
for pipelines, electricity lines and filtration fields pipelines.
Biogas plants takes
much more less area then filtration field. Thanks to
hermetic sealing of the fermentation reactors no odour can be traced.
The organic matter in fermented biomass is reduced due to the following
factors:
1) part of organics
fermented and converted into biogas;
2) the rest of
fermented organics is separated. .
The quality of
effluent after biogas plant is better. BOD and COD
levels reduced up to 8-10 times. However it is hardly to be called as
effluent as it a valuable product – bio-fertilizer.
In past times such
waste products recycled in the way of dry feed
production, which was highly energy consumptive. Bio-fertilizer
production with 8-10 kg of total nitrogen and useful microflora content
is more economically feasible.
Biogas yield:
Substrate |
Biogas
yield m3/t
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Grain distillery slope
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70
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Molasses distillery slope
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50
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Brewery’s grain
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160
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The biomass feeding into the reactor is batched, which preserves
sensitive methane bacteria from any harm. That gives process stability
and biogas production with high methane content. For biomass mixing
hydraulic mixing system is used. Produced biogas collected to outer
gasholders.
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