Division 1.10.1.5 VOC, PAH, and PCDD/F emissions
United Kingdom
| Technique | Description |
|---|---|
| Afterburner or thermal oxidiser | Combustion system in which the pollutant within the exhaust gas stream reacts with oxygen in a temperature-controlled environment to create an oxidation reaction |
| Regenerative thermal oxidiser | Combustion system that employs a regenerative process to utilise the thermal energy in the gas and carbon compounds by using refractory support beds. A manifold system is needed to change the direction of the gas flow to clean the bed. It is also known as a regenerative afterburner |
| Catalytic thermal oxidiser | Combustion system where the decomposition is carried out on a metal catalyst surface at lower temperatures, typically from 350 °C to 400 °C. It is also known as a catalytic afterburner |
| Biofilter | It consists of a bed of organic or inert material, where pollutants from off-gas streams are biologically oxidised by microorganisms |
| Bioscrubber | It combines wet gas scrubbing (absorption) and biodegradation, the scrubbing water containing a population of microorganisms suitable to oxidise the noxious gas components |
| Select and feed the raw materials according to the furnace and the abatement techniques used | The raw materials are selected in such a way that the furnace and the abatement system used to achieve the required abatement performance can treat the contaminants contained in the feed properly |
| Optimise combustion conditions to reduce the emissions of organic compounds | Good mixing of air or oxygen and carbon content, control of the temperature of the gases and residence time at high temperatures to oxidise the organic carbon comprising PCDD/F. It can also include the use of enriched air or pure oxygen |
| Use charging systems, for a semi-closed furnace, to give small additions of raw material | Add raw material in small portions in semi-closed furnaces to reduce the furnace cooling effect during charging. This maintains a higher gas temperature and prevents the reformation of PCDD/F |
| Internal burner system | The exhaust gas is directed through the burner flame and the organic carbon is converted with oxygen to CO2 |
| Avoid exhaust systems with a high dust build-up for temperatures > 250 °C | The presence of dust at temperatures above 250 °C promotes the formation of PCDD/F by de novo synthesis |
| Injection of adsorption agent in combination with efficient dust collection system | PCDD/F may be adsorbed onto dust and hence emissions can be reduced using an efficient dust filtration system. The use of a specific adsorption agent promotes this process and reduces the emissions of PCDD/F |
| Rapid quenching | PCDD/F de novo synthesis is prevented by rapid gas cooling from 400 °C to 200 °C |