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Teil 3 Seite 10-11
that is formed during the dehydration of fermenter outflow, as well as the elementary sul-
phur that is formed during de-sulphurisation are channelled into thermal conver-
sion/disposal. The stripped ammonia is subsequently catalytically oxidised into nitrogen.
Through the discharge of the ammonia stripper, the volume of water to be transported
outwards is significantly lower compared to animal meal production.
Operational data Applicability
Example for the results of the biogasproduction with matrial out of the Highpressuretem-
peraturehydrolysis
COD value
load
COD reduc-
tion
COD filtrated
reduction
Methane
content in the
bio gas
[kg/m³*d] [%] [%] [%] [m³/Mg]
Biogas recovery
~ 10 80 - 90 85 - 93 70 - 77 ~ 200 - 300
Economics
One tonne of raw material from the animal carcass processing sector yields between
200 and 300 m³ of biogas with an average methane content of above 70%. At an electrical
efficiency rate of 38%, 610 to 780 kWh/t of electrical energy are produced. If the electricity
is fed into the network in accordance with the Renewable Energy Law, the return is € 0,06
to 0,1 per kWh. This works out to € 36,6 to 78 per tonne. The costs for a currently required
production of animal meal, including the high energy consumption involved in the drying of
animal slurry and subsequent incineration can be saved. Only the considerably lower
quantities of mechanically dehydrated fermentation remnant needs to be dried. A feasibil-
ity study shows that, in comparison to animal meal production and subsequent incinera-
tion, a cost advantage of approx. € 50 can be attained in terms of thermal high pressure
hydrolysis.
The higher energy input during solubilisation has the consequence that the overall pro-
teins and fats are solubilised for biogas conversion. Pre-acidification, which would other-
wise take 15 days with this material, is therefore not required. In contrast to a conventional
biogas plant, in which e.g. category 3 material can be co-fermented in accordance with
the EU ordinance, a time reduction of 40% is achieved for this process.
Driving force for implementation
Compared to conventional process preconditions for category 1 material (133°C, 3 bar
and 20 min.) this results in the advantage that, per tonne of raw material, 600 kW is re-
tained. It has been established that at conventional block type thermal power stations the
ratio of electrical energy to heat is approximately 1:1. However, the heat resulting from
this is known to be difficult to utilise.
Example plants
St. Erasmus animal carcass conversion plant (technical college plant with 1000 kg/h)
Reference literature