Ecopure® RTO – Regenerative Thermal Oxidizer

First of all, the exhaust air to be treated flows through the hot thermal accumulator in the heat exchanger from the bottom to the top, where it almost reaches the combustion chamber temperature. A large proportion of the hydrocarbons are oxidized at this stage. In the combustion chamber of the Ecopure^® RTO, the exhaust air is heated to the reaction temperature of 800°C which is required for complete conversion. If necessary, a burner is used for this purpose. This allows the pollutants to be fully converted into harmless substances. The clean, hot gas then flows through another part of the thermal accumulator from the top to the bottom, where the heat is extracted from it. After this, the clean air is discharged from the system.

Ecopure^® RTO systems supplied by Dürr use less primary energy than conventional air pollution control systems, because they have a regenerative heat exchanger consisting of a ceramic thermal accumulator. A highly efficient process uses the energy in the hot exhaust gases to pre-heat the exhaust air that is being treated. 

As a result of its high internal heat recovery rate, where the concentration of pollutants is above approximately 1.5 g/Nm³, the system operates in autothermal mode. This means that the energy in the pollutants is sufficient to run the system without additional fuel (for example natural gas).

Ecopure^® RTO Air Pollution Control Systems can be made of a variable number of tanks, depending on the level of air purification required and the size of the volume flows. The exhaust gases flow through alternate tanks containing ceramic thermal accumulators. The exhaust air is pre-heated in the hot thermal accumulators, which keeps the amount of natural gas used to oxidize the air to a minimum.

A range of optional equipment is available that allows these systems to be used in almost all industrial sectors. This includes:

• Hot-gas bypass for use in over-autothermal mode
• Special materials (for example stainless steel alloy) or special coatings for corrosive media
• Bake-out function for removing deposits from regenerative heat exchangers
• Exhaust air pre-heating to reduce the relative humidity in the exhaust air inlet
• Lower explosion limit control system which adds controlled amounts of fresh air to exhaust air with high concentrations of pollutants
• Can be combined with flue gas treatment equipment to remove acidic components of flue gases, for example