中高温区碳酰肼还原NO_x和抑制二英的研究

Study on Inhibition of NO_x and Dioxin Emissions by Carbohydrazide Under Moderate to High Temperatures

试验研究了氧量为10.1%～16.7%的条件下,中高温区(450～1 050℃)碳酰肼还原烟气中NOx,及以不同方式加入焚烧炉和烧结系统时抑制二英的生成.结果表明,在烟气中氧量较高的条件下,碳酰肼在600℃和967℃左右,脱硝效率分别达到最大,850℃左右时最低,显示了双峰效应.将碳酰肼溶液喷入适当温度区域的烟气中,能明显降低二英在再合成温区(250～450℃)收集的飞灰中的二英含量;将碳酰肼混入烧结矿料中进行烧结锅试验,烧结烟气中的二英排放含量随着碳酰肼掺混量的增大而降低;当碳酰肼的掺混量(质量分数)达到0.1%时,烟气中二英的毒性当量浓度与不掺时相比降低了78.8%.研究表明碳酰肼可以多种方式加入焚烧炉和烧结炉中抑制NOx和二英的排放,是一种很有前景的NOx和二英双效抑制剂.

Experimental researches were carried out on the inhibition effects of carbohydrazide（CHZ） on NOx and dioxin emissions under moderate to high temperatures,namely De-NOx effect of CHZ was investigated in the temperature range of 450-1 050℃ with the O2concentration 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 NOx with dual temperature-linked peaks,i.e.the De-NOx efficiency peaks appeared both around 600℃ and 967℃,with a vale around 850℃.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℃ 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 NOx.