[Study on inhibition of NO(x) and dioxin emissions by carbohydrazide under moderate to high temperatures]

Experimental researches were carried out on the inhibition effects of carbohydrazide (CHZ) on NO(x) and dioxin emissions under moderate to high temperatures, namely De-NO(x) effect of CHZ was investigated in the temperature range of 450-1 050 degrees C with the O2 concentration between 10.1% and 16.7%; and its suppression effect on dioxin emissions was studied both by spraying CHZ solution into incineration flue gases and by mixing CHZ in iron ore in the sintering pot. It was proved that CHZ could reduce NO(x) with dual temperature-linked peaks, i. e. the De-NO(x) efficiency peaks appeared both around 600 degrees C and 967 degrees C, with a vale around 850 degrees C. The results also indicated that CHZ had good suppression effect on dioxin synthesis in the fly ash precipitated in the temperature range of 250-450 degrees C when CHZ solution was sprayed into flue gases at proper temperatures; comparably, for dioxin emissions from the iron ore sintering pot, the more CHZ mixed into iron ore, the less dioxin emissions took place; when the mixture proportion of CHZ (mass fraction) was up to 0.1%, the concentration of PCDD/Fs in TEQ in sintering flue gases was decreased by 78.8% compared to the scenario without CHZ mixing, showing that CHZ is an effective inhibitors for reducing dioxin emissions in the iron ore sintering furnace. All of these results showed that CHZ is a potential inhibitor for dioxin emissions from incinerators and iron ore sintering furnaces as well as a reduction agent for NO(x).