Filter and flue gas purificationWe supply filter systems according to the 17th and 27th BImSchV (Federal Immissions Control Ordinance). We have specialised in catalytic procedures for the lowest possible quantity of low-pollutant residues.

The filter system also includes continuous emissions monitoring with on-going measurement, evaluation and registration of the key exhaust parameters.

Our emissions monitoring systems are among the first to comply with the new European standard for uniform monitoring of emissions.


Metall-Technik's 3-Clean System

The furnace exhaust is guided through the thermal oxidising chamber via the exhaust duct to the chimney and flue gas purification system. The negative pressure is controlled by direct frequency control of the suction draught fan in the filter system. An exhaust air heat exchanger provides initial rapid cooling of the flue gas.

Additional cooling injects water into the flue gas cooling system which then evaporates. A control flap is used for cooling air intake, adjusting the filter intake temperature of approx. 165°C. The dust filter is responsible for pure dust separation. No sorbent is added to avoid any concentrations of dioxin, furan or heavy metals in the residues. The residue quantity is not synthetically enlarged. The dust filters are cleaned regularly and automatically by pneumatic means, with a compressor supplying compressed air.

Finally, the flue gas then flows through the KATsorber as final purification stage, with catalytic destruction of dioxins and furans, and absorption of heavy metals on doped pellets. This process stage separates out ultra-fine particles and gaseous pollutants. The flue gas flows through the catalyser with primary destruction of dioxins and furans. The catalyser also reduces the exhaust pollutants from the incineration process, the total carbon and carbon monoxide, in addition to the thermal oxidiser chamber.

The catalyser is also capable of reducing nitrogen oxides (if this should become necessary, for example following changes in legislation). To this end, ammonia can be added in the water cooler or cremation furnace. Installation of the KATsorbers in the clean gas ensures a very long service life. The catalyser and adsorber are not exposed to raw gas dust and are even separated from the dust filter itself (no mechanical load).

The components are specially rated to operation in the temperature window of approx. 160 / 120 °C. A thermal recovery unit is integrated in the KATsorber, which is capable of recovering approx. 50 kW for heating the building. The sorbens stage then ensures optimum separation and durability at approx. 120°C.

After the KATsorber, the flue gas passes through the fan and is expelled from the system. Continuous emissions measurement and monitoring of the flue gas take place before it enters the flue. The flue gas is conveyed out through the chimney.

Filter and flue gas purification process: Metall-Technik's 3-Clean-System

The flue gas is purified in the following phases:

Limit value as per 27th BImSchV:

  • carbon monoxide, 50 mg/Nm³
  • Total-C, 20 mg/Nm³
  • Dust, 10 mg/Nm³
  • Dioxin/Furan, 0,1 ng/Nm³
  • Mercury
  • Nitrogen oxide, 200 mg/Nm³
  • 17. BImSchV

Treated by:

  • Thermal oxidiser (850 °C), furnace
  • Thermal oxidiser (850 °C), furnace
  • Dry filter
  • Catalytic destruction in catalyser and adsorption
  • Chlorination and adsorption
  • Destruction in catalyser + NH4OH
  • (Ammonia water, ammonium hydroxide)


Emission values obtained in practical operations are approx. 50% and more below the limit levels! Residues: each cremation produces approx. 200 g filter dust. The residues are automatically purified in the dry filter and collected in a container, On request, the ash can be returned in the corresponding urn.

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