水合肼处理CaCO_3中高温净化焚烧烟气的研究

INCINERATION FLUE GAS SCRUBBING WITH HYDRAZINE HYDRATE TREATED CaCO_3 UNDER MODERATE TO HIGH TEMPERATURES

用水合肼对CaCO3进行处理,并将处理后的CaCO3用于中高温段净化焚烧烟气中的Hcl和NO。研究结果显示,因肼在加热过程中会分解甚至燃烧产生大量气体,使处理后的CaCO3在煅烧后比普通CaCO3的颗粒更细,反应活性更高,最终水合肼处理CaCO3吸收HCl气体的反应率随温度的升高而增大。当肼处理CaCO3中的肼含量在肼钙摩尔比为0．1-0．3的范围内变化到0．15时,其吸收HCl气体的反应率为最大。但当肼钙摩尔比大于0．15后,CaCO3在受热后板结而导致反应率降低。肼处理CaCO3在450-650℃范围内、烟气中氧量高于13％的条件下显示了对NO的还原效率,这是由于肼在此条件下对NO具有还原能力;而常用的还原剂氨在问样条件下对NO不具备还原能力。使用肼处理CaCO3可望实现在中高温段同时净化焚烧烟气中的酸性气体和NO。

In this paper, CaCO3 was treated with hydrazine hydrate and then used as absorbent for scrubbing HCl and NO in incineration flue gas within temperatures range of 450-650℃. For hydrazine will decompose or even deflagrate when heated and produce a large volume of gases, the treated CaCO3 will give much finer particles than common CaCO3 after calcination, which was proved by the experimental results. The researches also showed that when hydrazine/Ca ratiowas changed from 0.1 to 0.3, the treated CaCO3 corresponded to highest gaseous HC1 adsorption ability as hydrazine/Ca ratio around 0.15; at the same time higher temperature enhanced HCl absorption within the tested temperature range. But when the hydrazine/Ca ratio is over 0.15, particle aggregation happened when the treated CaCO3 was heated. Additionally, the treated CaCO3 showed a de-NOx efficiency up to 33%-35% even O2 concentration was in the range of 13%-17.5%; while ammonia, the common-used reducing agent for NOx showed none effect or even oxidized under the same conditions. Hydrazine hydrate exhibited a good potential for de-NOx under moderate to high temperatures, and the combination of hydrazine and CaCO3 will be a solution for simultaneous acid gases and NO removal from incineration flue gas under moderate to higher temperatures.