ROXITHERM Regenerative thermal oxidation (RTO) for the mechanical-biological treatment of waste (MBT)

Posing the tasks

For the mechanical-biological systems for the treatment of waste, the high demands of the 30th BImSchV with regard to emission values must be complied with. Continuous emission measurements monitor a maximum emission exceedance of 96 h/a. Additionally, an official requirement for a minimum dwell time in the combustion chamber of 2 s exists.

Solution / Highlight

Preliminary studies and comparable applications show that a combination of an acid washer and subsequent oxidation in a 3-chamber RTO system will fulfil the emission requirements of the 30th BImSchV. Ammoniac is separated in the acid washer so that nitrous oxide will not form in the combustion chamber of the RTO. The 3-chamber RTO system, model ROXITHERM RTK, reduces the hydrocarbons to values far lower than the TA-Luft values.

In order to achieve availability demands, a redundant system design is necessary. In this case, later system enhancements resulted even in a 3-level arrangement. This makes possible the switching off of a complete line without reducing the total volume flow, which has proven to be very advantageous.

Organosilicon compounds are found in the exhaust air of waste treatment systems, which necessarily oxidise to the dust-form solid, SiO2, in the combustion chamber. This solid matter can clog the heat exchanger, which will have to be cleaned at specific time intervals.

In addition to the normal gas burners with gas lances in the combustion chambers, the 3 lines are outfitted for using the available landfill gas available on the premises. Depending on the demand, a selection can be made between two different combustion gases.