The bubbling bed combustion system
is the heart of every thermal sewage
sludge treatment plant. It ensures
stable, autothermal combustion even
with varying fuel properties.
Thanks to staged air supply with
primary and secondary air and
optional flue gas recirculation,
low primary emissions and high
burnout can be achieved. Today’s
high requirements for ash quality,
emissions and availability are met by
Doosan Lentjes’ adiabatic bubbling
bed furnace with staged combustion
thanks to the high variability of air
preheating and distribution. This
enables stabilisation of the bed and
freeboard temperatures without shortterm
readjustment of fuel moisture.
Our technology is characterised by
high availability, energy self-sufficiency
and a long service life – important
prerequisites for economical operation
and high-quality ash for subsequent
phosphorus recovery.
The optimal design of the steam
generator is crucial for the efficient
use of the energy contained in
sewage sludge. Our boiler concepts
combine high efficiency with compact
design and can be flexibly adapted
to project-specific requirements.
In the steam generator, the flue
gas is cooled from combustion
temperature to a gas temperature,
which enables downstream ash
precipitation suitable for phosphorus
recovery and a state-of-the-art
flue gas cleaning system. The
heat from combustion can be
utilised, for example, for sewage
sludge drying and/or in a water
steam cycle.
The integrated air preheater ensures
stable temperatures in the combustion
process and contributes to autothermal
combustion even with changing fuel
properties.