The patented SynGas CHP module is characterized by its particularly high, electrical energy recovery from the dried sewage sludge. The synthesis gas generated in the fluidized bed reactor is converted into electricity and heat in a highly efficient combined heat and power plant (CHP) after a treatment stage. The excess electricity can be fed to the wastewater treatment plant and the heat to sludge drying.
Since a large part of the energy contained in the syngas is converted into electricity in the SynGas CHP module, less heat energy is available for drying the sewage sludge.
This energy deficit can be covered by using the available energy from digester gas. The waste heat from the drying process is in turn available for heating the digestion towers.
Thus, the overall system remains thermally self-sufficient and the use of additional energy sources is avoided.
If heat has to be extracted for heating the digesters, the digesters can henceforth be heated using the recoverable low-temperature waste heat from the sewage sludge drying process. Thus, the entire system remains thermally self-sufficient without the need for an additional energy source.
Advantages of the SynGas CHP Module:
utilization of the high efficiencies of CHP units
compact exhaust gas cleaning due to small air mass flow during gas generation
in combination with an anaerobic sludge digestion plant can lead to an energy self-sufficient wastewater treatment plant
Process description: CHP Module
1) Sewage sludge with a dry matter content of 85-95 %.
2) Limestone for admixture as the first desulfurization stage.
3) splitting of the chemical compounds of the sewage sludge in the thermolysis corner to produce thermolysis gas, carbon and ash – stage 1
4) substochiometric combustion of carbon at 870 °C to produce synthesis gas – stage 2. Destruction of all organic toxins.
5) discharge and cooling of the phosphorus-rich and virtually carbon-free ash pellets.
Synthesis gas purification and cooling
6) coarse dedusting of syngas in a cyclone separator
7) Heat recovery from syngas for supply in stage 1
8) Heat recovery from flue gas for supply in stage 1
9) Fine dust removal from synthesis gas
10-12) Synthesis gas scrubbing: further cooling of the synthesis gas and separation of dust residues, tar and pollutant gases
13-15) Activated carbon filter for removal of heavy metals and remaining pollutants
16) Utilization of the purified synthesis gas in a combined heat and power plant for the generation of electricity and process heat
17) Exhaust gas cleaning with urea