Fluidized bed incinerator
The fast incineration in a fluidized bed incinerator makes this technology attractive for the treatment of large volumes of non-recyclable waste. The ovens have been built to recover energy efficiently. The heat that comes from the thermal treatment is recovered in a vertical steam boiler. The steam produced is fed into a turbine generator and converted into electricity, which is supplied to the public electricity grid.
The wood waste is stored in a hall where it is fed through an automatic system for preliminary treatment. In this preliminary treatment phase, any metals are removed and the pieces of wood that are too large are sifted out and broken down using a breaker. We clean the scrap fraction so that we can re-use it.
The wood fraction which has been broken down is then stored in the buffer silos before being fed into the incinerator.
E-Wood’s fluidized bed incinerator has 2 pairs of feed screws which feed wood waste into the fluidized bed gradually. The incineration process takes place in a strong rotating (swirling) bed of sand at a temperature of 850 °C minimum. The wood mixes with the hot sand, gasifies and combusts. The high temperature and the efficient heat transfer ensure proper incineration. The flue gases, along with the fly ash, go via the post-combustion chamber to the steam boiler.
Screws remove the sand and bottom ash from the incinerator. The sand is sifted and put back into the fluidized bed. The bottom ash is stored in containers and treated in an external facility where the different fractions are recovered as much as possible.
The fluidized bed incinerator is equipped with intensive flue gas cleaning. A large part of the facility is the filter systems for optimum purification of the incinerator gases. Cyclones remove a large part of the fly ash. In the reactor, lime is injected to capture the Cl and S components and activated carbon is injected to remove heavy metals and dioxins. The baghouse filters separate out the reacted lime and activated carbon together with the last fly ash. The flue gas purification residues are solidified first if necessary, and then landfilled in a class 1 landfill.
In addition to using techniques that limit the formation of dioxins and NOx (nitrogen oxides), urea is also injected into the incinerator to mitigate the impact on the environment. Continual monitoring of the emissions guarantees that the purified flue gases that leave the chimney, always meet the strictest environmental standards and we remain (far) below the limits.