Gas Treatment

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Prodesa is an engineering company specialized in the supply of turnkey plants for treatment of volatile organic compounds (VOCs).


  • Risk analysis (HAZOP)
  • Energy recovery systems
  • Plants revamping
  • Plant efficiency optimisation: performance and consumptions

Available Technologies

  • Regenerative thermal oxidation
  • Rotoconcentrator

Regenerative thermal oxidizers

Regenerative thermal oxidizers consist of several vertical prism towers, partially filled with ceramic material, and an oxidation chamber which joins the towers.

The gas flow goes through one tower and absorbs energy from the filling (heated in prior cycles). These gases reach the oxidation chamber where the reaction takes place. Afterwards they go through another tower giving off heat to the filling.

Several watertight valves switch cyclically in a way that allows the gas to enter always through a warm bed.

The inversion of the flux direction would cause a little waste gas emission through the stack. In order to avoid this, a third tower takes part in the purge process by re-circulating a bit of flow to the fan.

Regenerative thermal oxidation characteristics:

  • Gas flows from 1.000 Nm3/h
  • Reaction temperature: 750 – 1100 ºC
  • It allows an energy efficiency up to 95%
  • If the inlet concentration of the waste gas is lower than 2,5 g/Nm3, it is designed a system with 2 towers. For higher concentrations, it is designed a system with 3 towers.
  • It works without fuel from 1,5 – 2 g/Nm3 depending on the organic compounds LHV
  • Suitable for large gas flows with low VOC concentration
  • It enables working with concentrations up to 25 % LEL
  • High VOC destruction ranges> 99%


This technology is based on the adsorption properties of activated carbon or zeolites. Thanks to their porosity, they can adsorb a great part of the organic compounds in the gas.

It consists of a rotary drum which allows the concentrator to have always an area on absorption phase, another on regeneration phase and another one on refrigeration.

VOCs are kept on the adsorbent material and come out purified to the atmosphere. In order to regenerate the zeolite, a low warm air flow circulates through it. This air contains a high VOC concentration and is sent to a thermal treatment or to recuperation with low operational costs.