Heat recovery systems may be added in the field or included with the purchase order when originally ordered.  Nacah Tech systems are designed with the optimum operating costs in mind and target the customer’s objectives.  If minimizing fuel costs is the priority, an offgas preheater or combustion air preheater is incorporated.  If capturing the heat that would otherwise exit up the stack via another method such as producing steam, hot water, or hot oil (as shown in photos), that heat recovery method is included.  Sometimes, these methods are combined in the system to increase the heat recovered and increase the plant’s sustainability and lessen its carbon footprint.  RTOs use ceramic media to preheat the incoming offgas, recuperative thermal oxidizers regularly use gas to gas heat exchangers for preheating, and those applications with high heat release or dirtier gas may require different options like the boiler or oil heater.  

Retrofits and upgrades also increase the efficiency of systems, reduce plant fuel consumption, and increase the life of the whole system.



  • Basic design of systems including estimation of nature and quantity of VOC’s provides comfort level for plant engineers/operators.
  • Optimising choice of Activated Carbon usage due to vast experience in the field. Saves initial costs, assures proper capture, and optimizes operating costs.
  • Individually designed systems to suit particular applications depending on type and quantities of VOC ‘s. Optimizes costs and operation success.

Air Pollution Control

& other Systems

Fuel efficient, progressive and cost sensitive

In a Fluid Bed Concentrator System, exhaust enters through a series of perforated trays containing media. The media adsorbs VOCs and is continually removed from the trays, regenerated, and returned.


This is the easiest and most basic form of VOC control,
wherein a particular grade of Carbon is chosen based on tests on the streams and on experience. The VOC’s are then passed through the Carbon bed to adsorb them and
to ensure that the vapours coming out are harmless to the atmosphere. This is carried out in Carbon canisters or Tanks, depending on the flow and the site conditions. Basically, a Fixed Bed or a Fluidised Bed option is possible.


Popular for higher VOC concentrations, thermal oxidation will combust the VOC gases to achieve very high levels of purity of the vented air. Obvious advantages are non-replacement of the spent carbon bed.

Nacah tech LLC


Volatile Organic Compounds ( VOC ), are generated in streams where oils are present in refinery and petrochemical effluents or streams. These regularly consist of BTEX (Benzenes, Toluenes, Xylenes etc.), and other organic compounds which add to the odour and are often required to be controlled whereas they may have been previously vented into the atmosphere.


All VOC generating points such as oil sumps, storage tanks for slop and feed oils, separator tanks like API’S, TPI’s, DAF systems, etc. need to be fitted with the VOC control system. This control may be either by Carbon adsorption and subsequent desorption, or by use of thermal oxidiser systems, to ensure that the vapours escaping from these units are controlled to contain the VOC’s.