钢渣与活性炭协同脱硝的性能研究
发布时间：2018-11-03 10:16
【摘要】：随着国家环保法规的日益严格,冶金行业NO_x的排放也将严格控制。目前,部分钢铁冶金行业烧结工序采用活性炭法同时脱除SO2、NO_x、二VA英等多种有害气体,但活性炭脱硫脱硝成本较大。冶金行业不仅氮氧化物排放量高,产生的固废量巨大,如钢渣累积量大,但利用率低。钢渣中仍含有一定量的未被利用的铁氧化物,众多学者研究表明,铁基催化剂具有廉价易得、脱硝活性窗口宽、抗毒能力强等特点,其在选择性催化还原SCR脱硝工艺中具有良好的应用前景。因此,若以钢渣为原料与活性炭制备复合吸收剂,不仅为钢渣找到一条新的利用途径,而且可以利用钢渣与活性炭联合脱硝实现催化协同吸附的共同作用,亦可降低活性炭的脱硝成本,这对于实际工程应用将具有重要的意义。收集宝钢不同种类的钢渣与煤基活性炭样品经过预处理制备成不同掺混比例的混合物(以下简称“复合吸收剂”),并于电加热石英玻璃管反应器进行钢渣/活性炭复合吸收剂的最佳配比实验研究同时进行了复合吸收剂脱硝性能的实验研究,并综合考虑了反应温度、NO浓度、氧气浓度、钢渣种类等的影响。基于响应面法优化了实验运行条件及工作参数并预测了实验的最佳反应工况点及效率。在最佳反应工况点分别对不同铁含量钢渣制备的复合吸收剂进行了实验研究,进行了BET、XRF、SEM表征及TG分析,并分析了复合吸收剂的脱硝过程。实验发现复合吸收剂的最佳活性掺混比例为活性炭/钢渣=2:1。活性炭和钢渣均有脱硝活性,其中活性炭脱硝率较高可达36%,但随着温度的升高效率逐渐降低。钢渣脱硝率随着温度升高而升高,最高为13%。活性炭钢渣掺混制备的复合吸收剂的脱硝率大于同样反应条件下活性炭的脱硝率,且在低温区复合吸收剂的脱硝率大于活性炭和钢渣的脱硝率之和,说明活性炭与钢渣制备的复合吸收剂存在协同脱硝作用。实验结果表明反应温度与NO初始浓度对复合吸收剂脱硝率的影响为“负相关”,烟气中氧含量对复合吸收剂脱硝率的影响为“正相关”。结合响应面法复合吸收剂反应条件优化实验结果可知温度、NO浓度、氧含量等三因素对吸收剂效率的影响均显著,其中温度与氧含量二者的交互作用明显。优化器预测的最佳工况点为反应温度116℃、O2含量12%、NO浓度400ppm,最大效率为72.5%,复合吸收剂最佳工况点的实验验证结果为71.4%。通过对活性炭、钢渣、复合吸收剂进行表征分析(包括TG、XRF、BET、SEM分析等),表明活性炭具有一定的热稳定性,单质铁含量是影响复合吸收剂效率的主要内在因素,初步分析复合吸收剂脱硝过程存在活性炭吸附作用以及钢渣催化作用。
[Abstract]:With the increasingly strict national environmental protection regulations, metallurgical industry NO_x emissions will be strictly controlled. At present, activated carbon is used to remove many kinds of harmful gases such as SO2,NO_x, and VA in some iron and steel metallurgical industry simultaneously, but the cost of desulfurization and denitrification of activated carbon is high. The metallurgical industry not only has high nitrogen oxide emissions, but also produces a large amount of solid waste, such as large accumulative amount of steel slag, but low utilization rate. Steel slag still contains a certain amount of unused iron oxides. Many scholars have shown that iron based catalysts are cheap, easy to obtain, wide denitrification active window, strong ability to resist toxicity, etc. It has a good application prospect in selective catalytic reduction of SCR denitrification process. Therefore, if the composite absorbent is prepared from steel slag and activated carbon, it can not only find a new way for the utilization of steel slag, but also make use of the combined denitrification of steel slag and activated carbon to achieve the cooperative catalytic adsorption. It can also reduce the denitrification cost of activated carbon, which will be of great significance for practical engineering application. The samples of steel slag and coal-based activated carbon of Baosteel were pretreated to produce a mixture of different blending ratios (hereinafter referred to as "composite absorbent"). The optimum ratio of steel slag / activated carbon composite absorbent was studied in an electrically heated quartz glass tube reactor. The denitrification performance of the composite absorber was also studied. The reaction temperature, NO concentration and oxygen concentration were taken into account. The influence of steel slag types, etc. Based on the response surface method, the operating conditions and operating parameters of the experiment were optimized and the optimum reaction conditions and efficiency of the experiment were predicted. At the optimum reaction condition, the composite absorbent prepared from steel slag with different iron content was experimentally studied, characterized by BET,XRF,SEM and analyzed by TG, and the denitrification process of composite absorber was analyzed. It is found that the optimum ratio of active carbon to steel slag is 2: 1. Both activated carbon and steel slag have denitrification activity. The denitrification rate of activated carbon is higher than that of steel slag, but the efficiency decreases with the increase of temperature. The denitrification rate of steel slag increases with the increase of temperature, and the highest is 13%. The denitrification rate of the composite absorber prepared by mixing the steel slag with activated carbon is higher than that of the activated carbon under the same reaction conditions, and the denitrification rate of the composite absorber at low temperature is greater than the sum of the denitrification rate of the activated carbon and the steel slag. It shows that the composite absorbent prepared by activated carbon and steel slag has synergistic denitrification effect. The experimental results show that the effect of reaction temperature and initial concentration of NO on denitrification rate of composite absorber is "negative", and the effect of oxygen content in flue gas on denitrification rate of compound absorber is "positive correlation". The experimental results show that the effects of temperature, NO concentration and oxygen content on the absorbent efficiency are significant, and the interaction between temperature and oxygen content is obvious. The optimum operating conditions predicted by the optimizer are reaction temperature 116 鈩，
本文编号：2307494
[Abstract]:With the increasingly strict national environmental protection regulations, metallurgical industry NO_x emissions will be strictly controlled. At present, activated carbon is used to remove many kinds of harmful gases such as SO2,NO_x, and VA in some iron and steel metallurgical industry simultaneously, but the cost of desulfurization and denitrification of activated carbon is high. The metallurgical industry not only has high nitrogen oxide emissions, but also produces a large amount of solid waste, such as large accumulative amount of steel slag, but low utilization rate. Steel slag still contains a certain amount of unused iron oxides. Many scholars have shown that iron based catalysts are cheap, easy to obtain, wide denitrification active window, strong ability to resist toxicity, etc. It has a good application prospect in selective catalytic reduction of SCR denitrification process. Therefore, if the composite absorbent is prepared from steel slag and activated carbon, it can not only find a new way for the utilization of steel slag, but also make use of the combined denitrification of steel slag and activated carbon to achieve the cooperative catalytic adsorption. It can also reduce the denitrification cost of activated carbon, which will be of great significance for practical engineering application. The samples of steel slag and coal-based activated carbon of Baosteel were pretreated to produce a mixture of different blending ratios (hereinafter referred to as "composite absorbent"). The optimum ratio of steel slag / activated carbon composite absorbent was studied in an electrically heated quartz glass tube reactor. The denitrification performance of the composite absorber was also studied. The reaction temperature, NO concentration and oxygen concentration were taken into account. The influence of steel slag types, etc. Based on the response surface method, the operating conditions and operating parameters of the experiment were optimized and the optimum reaction conditions and efficiency of the experiment were predicted. At the optimum reaction condition, the composite absorbent prepared from steel slag with different iron content was experimentally studied, characterized by BET,XRF,SEM and analyzed by TG, and the denitrification process of composite absorber was analyzed. It is found that the optimum ratio of active carbon to steel slag is 2: 1. Both activated carbon and steel slag have denitrification activity. The denitrification rate of activated carbon is higher than that of steel slag, but the efficiency decreases with the increase of temperature. The denitrification rate of steel slag increases with the increase of temperature, and the highest is 13%. The denitrification rate of the composite absorber prepared by mixing the steel slag with activated carbon is higher than that of the activated carbon under the same reaction conditions, and the denitrification rate of the composite absorber at low temperature is greater than the sum of the denitrification rate of the activated carbon and the steel slag. It shows that the composite absorbent prepared by activated carbon and steel slag has synergistic denitrification effect. The experimental results show that the effect of reaction temperature and initial concentration of NO on denitrification rate of composite absorber is "negative", and the effect of oxygen content in flue gas on denitrification rate of compound absorber is "positive correlation". The experimental results show that the effects of temperature, NO concentration and oxygen content on the absorbent efficiency are significant, and the interaction between temperature and oxygen content is obvious. The optimum operating conditions predicted by the optimizer are reaction temperature 116 鈩，
本文编号：2307494
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