改性活性炭催化水解—氧化耦合法净化黄磷尾气中HCN的研究
发布时间：2019-01-10 15:37
【摘要】：HCN是一种典型的“非常规”有毒有害污染气体,是一种有苦杏仁味的剧毒物质。黄磷生产过程中会产生大量污染气体,气体成分复杂,其中就包括HCN,其浓度为400-1000mg/m3。本文在对比国内外研究净化HCN方法的基础上,针对改性活性炭催化水解-氧化耦合法净化黄磷尾气中的HCN展开研究。活性炭具有巨大的表面积和复杂的孔隙结构,其来源丰富、成本低廉、改性方法多种多样,是一种良好的催化剂载体。因此,本论文以活性炭为载体,进行了HCN催化水解-氧化耦合催化剂的研究。首先考察了单一过渡金属改性活性炭(AC)的耦合催化性能,结果表明：过渡金属改性的活性炭显著提高了对HCN的去除能力,其中Cu改性的AC-Cu催化剂表现出最好的催化活性,在250-350℃,HCN去除率大于98%。N2选择性在300℃达到48.8%。因此,本文重点选取Cu作为后续研究的活性组分。反应温度、氧含量、相对湿度以及催化剂焙烧温度都明显影响对HCN的催化活性,其中反应温度的影响最为明显。为拓宽活性炭的反应温度窗,提高HUN转化率与N2选择性,利用具有储氧活性的磺化酞菁钻及稀土金属元素Ce进一步改性负载Cu氧化物的改性活性炭催化剂。并对改性后的活性炭进行多角度表征,最后考察比较了AC-Cu与AC-Cu-CoPcS-Ce的活性稳定性,持续运行48小时,催化剂一直保持较高的活性没有受到任何影响,HCN的转化率均维持在98%以上,结果表明两种催化剂都具有较好的活性稳定性。由于AC-Cu-CoPcS-Ce的催化活性温度相比AC-Cu低,所以AC-Cu-CoPcS-Ce催化剂更具有优势。采用X射线衍射(XRD)、电感耦合等离子体-原子发射光谱(ICP-AES、N2吸脱附(BET、X射线光电子能谱(XPS)、傅里叶红外(FT-IR)、程序升温还原(H2-TPR)以及程序升温脱附(TPD)等手段对催化剂进行多角度表征,研究了催化剂的晶体结构、孔结构、形貌以及催化剂可能的催化反应原理。通过以上活性评价及表征结果,推测了可能的反应机理。根据推理,催化水解-氧化耦合过程中,HCN水解反应与HUN氧化反应相互关联相互促进,HUN水解过程产生NH3与CO, HCN氧化过程产生N2、NOx、N2O等,NH3进一步与反应系统中存在的O2反应选择性生成N2；同时,水解过程产生NH3与HCN氧化过程产生的NOx进一步发生反应生成N2,从而比较彻底的转化HCN废气。
[Abstract]:HCN is a typical "unconventional" toxic and harmful pollutant gas, and it is a highly toxic substance with bitter almond flavor. Yellow phosphorus production can produce a large amount of polluting gas, the gas composition is complex, including HCN, concentration of 400-1000 mg / m3. On the basis of comparing the domestic and foreign methods of purifying HCN, the HCN purification from yellow phosphorus tail gas by the coupling method of catalytic hydrolysis and oxidation of modified activated carbon was studied in this paper. Activated carbon has a large surface area and complex pore structure, which has rich sources, low cost and various modification methods, so it is a good catalyst carrier. Therefore, in this paper, HCN catalytic hydrolysis-oxidation coupling catalyst was studied with activated carbon as the carrier. First, the coupling catalytic performance of single transition metal modified activated carbon (AC) was investigated. The results showed that the modified activated carbon could significantly improve the removal capacity of HCN. The Cu modified AC-Cu catalyst showed the best catalytic activity, and the removal rate of HCN was higher than that of 98%.N2 at 250-350 鈩，
本文编号：2406490
[Abstract]:HCN is a typical "unconventional" toxic and harmful pollutant gas, and it is a highly toxic substance with bitter almond flavor. Yellow phosphorus production can produce a large amount of polluting gas, the gas composition is complex, including HCN, concentration of 400-1000 mg / m3. On the basis of comparing the domestic and foreign methods of purifying HCN, the HCN purification from yellow phosphorus tail gas by the coupling method of catalytic hydrolysis and oxidation of modified activated carbon was studied in this paper. Activated carbon has a large surface area and complex pore structure, which has rich sources, low cost and various modification methods, so it is a good catalyst carrier. Therefore, in this paper, HCN catalytic hydrolysis-oxidation coupling catalyst was studied with activated carbon as the carrier. First, the coupling catalytic performance of single transition metal modified activated carbon (AC) was investigated. The results showed that the modified activated carbon could significantly improve the removal capacity of HCN. The Cu modified AC-Cu catalyst showed the best catalytic activity, and the removal rate of HCN was higher than that of 98%.N2 at 250-350 鈩，
本文编号：2406490
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