Thermal Sewage Sludge Recycling - Process Efficiency Information and Optimizing System

Safe and ecological disposal of wastewater sludge from sewage plants
is in discussion for years. In focus is the treatment of relics from
drugs, heave metals and recovery of natrium. The hardest difficulty to
overcome is usually to cope with the high moisture, because drying,
which allows incineration with an acceptable ammount of primary energy
is not only questionable from an economical point of view, but it also
comes along strong olfactory harassments.

The approach of this project is different. It is explicitly a high
amount of primary energy used, but this energy is used to process
synthetic fibers in a downstreamed process. The economical advantage for
the downstreamed process comes from the utilization of the additional
calorific value of the sewage sluge, which is reduced to ash.
The remaining low calorific heat is used to dry the incomming sewage
sludge thermaly. The only aim from this step is to overcome the moistures enthalpy of
evaporation, because the outlet air from this process goes directly to
furnace avoiding odor trouble. The point to overcome the moistures
enthalpy is a key technology for the economical success of this plant,
because of the high moisture and the fact that low calorific heat cannot be used in
the downstream process.

In this project we develop an open loop optimization for several
timesteps and a state estimation of the process to utilize it in a
model predictive control loop. Goal of this optimization is to reduce
the whole amount of primary energy going along with process restritions to
keep the plants operation safe and keeping exhaust gas parameters in
its boundary values.


Opens internal link in current windowThorsten Gellermann (gellermann [ a t ] math [ d o t ] uni-erlangen [ d o t ] de)

Opens internal link in current windowBjörn Geissler (bjoern.geissler[ a t ] math [ d o t ] uni-erlangen [ d o t ] de)


APE Engineering GmbH


This project is carried out is supported by the Bavarian ministry for Economics,
Infrastructures, Traffic, and Technology under grant number IUK 420/002.