A pilot experimental platform for control of dioxins emission from incineration has been established by State Key Laboratory of Environmental Chemistry and Ecotoxicology (SKLECE), Research Center for Eco-Environmental Sciences. The platform was built on the circulating fluidized bed incinerator with a capacity of 2×500 ton/day at a municipal incineration plant in Taian, Shandong Province. The pilot platform is comprised of feeding system, heat exchanger, reaction system, air pollution control device and automatic control system. Based on the results of experiments carried out on the pilot platform from Feb. 2010 to April 2011, the technique for inhibiting dioxins formation has recently achieved process.

Precursor pathway and de novo pathway are the two major dioxins formation mechanisms during the waste incineration and cooling of flue gas. The addition of some chemical compounds into the flue gas could suppress the dioxins formation. Calcium-based inhibitor invented by SKLECE was found to be very effective for suppressing the dioxins formation both from de novo pathway and from precursor pathway. Three national invention patents and one PCT patent on inhibition of formation of dioxins applied by SKLECE have been authorized.

The obtained results shown that the reductions of dioxins concentration by stack gas and fly ash were about 79% with the inhibitor added compared with that without inhibitor addition, while the TEQ reduction was about 70%. The combined application of calcium-based inhibitor with high efficient bag filters could reduce the dioxins emission in flue gas below the limit of Europe Union (0.1 ng TEQ Nm^-3).

The traditional pollution control technique for dioxins emitted from waste incineration was “absorbent of active carbon + bag filters for dust removal”. The reduction principle is the transfer of dioxins from stack gas into fly ash. Although the dioxins concentration emitted into air was decreased, the total dioxins occurrence in stack gas and fly ash is not reduced. The novel control technique developed by SKLECE is preventing the dioxins formation, thus decrease the dioxins emission. The obtained results show that the levels of dioxins in both stack gas and fly ash were obviously reduced. Moreover, the cost of technique is low, and the technique is easily promoted. Thus, the inhibiting technique might be promising in controlling dioxins emission from waste incineration.