Sulfur acts as an effective inhibitor of dioxins formation

and such action has been proved in laboratory studies

but few studies in actual waste incinerators are reported. To control the emission of dioxins from hazardous waste incinerator (HWI) effectively

a new pilot scale system with SO2 recycling and fly ash thermal treatment from the bypass flue gas in an actual HWI (50 t·d-1) was developed. An absorbent was used to realize SO2 recycling by which SO2 absorption was conducted by the absorbent in the flue gas and SO2 desorption was conducted in the low-temperature thermal treatment system. The capacity of SO2 accumulation and inhibition of dioxins synthesis of the system was studied

and it was found that the system could operate continuously. The system could maintain a high SO2 concentration of 100 mg·m-3 after adding a certain amount of other S-compounds and reduce more than 80% of dioxins emission factor. Therefore

the SO2 recycling inhibition technology provides guidance for dioxin emission reduction during waste treatment

and the long-term stable operation of the system will play a key role in achieving low emission of dioxins

but some relevant parameters of the pilot system still need further optimization.