The fluidized bed system or suspended silica is a powerful system containing hot sand and operating at relatively low combustion temperatures, between 450 – 650 °C in order to completely evaporate and oxidize all organic material.
The organic fraction is submerged in the bubbling sand reactor by means of a feeding system like a screw, pump or conveyor belt, depending on the physical properties (viscosity) of the waste. Prior to the insertion of the organic waste, the reactor has been heated up to a very homogeneous stand-by temperature. Once the temperature has been reached, the system can work independently without adding external energy sources.
The fluidized bed reactor contains calibrated sand which is brought in a liquid-like state (suspended particles) by the injection of air and gas.
In this condition, the suspended silica sand becomes a very powerful reactor, in which a fast and complex physiochemical process will evaporate the slugde very fast. Water and liquids in the sludge are immediately evaporated when they come into contact with the hot sand. All organic compounds are strongly oxidized and completely gasified.
The flue gases of an incinerator installation are routed to a flue gas cleaning installation. The so-called after burner is operating at a constant temperature of 850 to 1100°C. All orangic pollutants (odor, VOC, ...) are stronly oxidized to CO2, H2O, ...
For classic VOC’s a combustion temperature between 750 and 1000 °C is sufficient. Environmentally-harmful gases need a temperature between 1000 °C and 1200 °C in order to ensure that these components are destroyed.
The further treatment of the flue gases contains an ultra-performant and temperature resistant ceramic filter, which collects dust to less than 5 mg/Nm³ in the emissions. A lime injection installation is necessary to remove halogens and sulphur-containing compounds in the flue gas, to absorbe components (Chlorine, Fluorine,...).
A heat exchanger can be installed to recover the heat from the flue gas treatment, which can be used as a fuel or for the production of hot water or steam. The high temperature of the flue gases is reduced, by exchanging the heat from the flue gases to another medium.
Consequently the temperature of the exhaust is sufficiently lowered before filtering. The ceramic filter installation ensures that dust and all inorganic fraction is captured. The fan finally exhausts the cleaned flue gases into the atmosphere through the chimney.