浅议氰化氢的聚合与预防

文章总结了氰化氢聚合的条件与类别,并对预防聚合的办法进行了讨论。     

Pd(Ⅱ)、Ni(Ⅱ)金属催化剂在CO/烯烃共聚合中的发展

简要地回顾了近20年来Pd(Ⅱ)、Ni(Ⅱ)金属催化剂在CO／烯烃共聚合应用中的发展状况，并按不同结构配体类别对催化剂的结构、聚合机理等进行了简单的讨论。后过渡金属催化剂的发现，使得CO／烯烃的交替共聚合有了巨大的突破。     

结构与性能的关系：线性和星形枝化宏观结构（1）

溶液阴离子聚合可能是合成具有精确结构的聚合物分子最有用的工具。阴离子增长中心固有的稳定性，使其聚合控制水平远高于其他重要工业化价值的聚合体系。“宏观结构”这一术语用来描述聚合物链的结构特征，包括相对分子质量、相对分子质量分布及枝化的程度及类别。聚合物主链的枝化点，     

聚吡咯及其复合材料的研究进展

介绍了聚吡咯及其纳米复合材料的最新研究进展,综述了聚吡咯的聚合机理、制备方法、应用范围等,同时也介绍了聚吡咯复合材料的主要类别及应用领域,最后对聚吡咯及其复合材料的发展前景进行了展望。     

聚氧化乙烯的性质及其合成

介绍了聚氧化乙烯的主要性质，采用有机金属化合物为主体的多组分催化剂进行环氧乙烷的聚合试验，探讨了聚合收率，聚合物分子量与聚合时间的关系，催化剂浓度，聚合温度，催化剂贮存时间对环氧乙烷聚合的影响。在较佳的工艺条件下制得分子量主同于５００万的白色粒状聚氧化乙烯，聚合收率大于９５％（重量）。     

可聚合乳化剂的类型及乳液聚合（续）

介绍了一些新型的乳化剂－可聚合乳化剂，分别按亲水基类型，可聚合基因类型和可聚合基因在分子中位置等对其进行了分类。综述了各类可聚合乳化剂研究及应用情况，展望了其发展前景。     

提高丁苯橡胶聚合转化率过程中胶乳粘度的控制

针对高转化率丁苯橡胶聚合过程中所出现的随着聚合反应转化率的提高，胶乳粘度随之增加这一问题，对聚合配方进行了调整，有效地拉制了聚合后期胶乳的粘度，确保提高转化率不会因聚合后期胶乳粘度的增加而影响生产远行。     

偏氯乙烯乳液聚合

对偏氯乙烯乳液聚合配方如引发剂，乳化剂，共聚单体，pH值调节剂，聚合工艺如聚合温度、搅拌强度和聚合方式等进行了较全面的叙述。     

微乳液聚合和细乳液聚合

分别从微乳、细乳体系的形成，聚合机理及聚合特点等方断对两者进行了比较，并对各自的应用前景进行了展望。     

聚丙烯酸钠高吸水性树脂的性能改善

采用水溶液聚合法合成了聚丙烯酸钠高吸水性树脂，并通过改变聚合过程中的添加剂和进行吸水性树脂的表面交联反应处理，对产品性能进行了研究。结果表明在聚合过程中添加适当的添加剂和对产品进行表面交联反应处理，能显著地改善产品性能。     

HCN synthesis from methane and ammonia over platinum

The mechanism of the HCN formation from ammonia and methane over Pt black was investigated using a temporal analysis of products (TAPs) reactor system. At 1173 K the hydrogen cyanide production rate depends on the order of introducing the reactants. HCN is formed rapidly on the methane pulse just after introducing ammonia. However, a slow formation of HCN is observed on the ammonia pulse that follows a methane pulse. Moreover the form of the HCN response resembles closely that of the nitrogen and hydrogen also released during the ammonia pulse. Thus, the rate-determining step for the formation of HCN is the decomposition rate of ammonia. A reaction sequence based on elementary steps is proposed for the HCN synthesis. The formation of HCN after pulsing H₂ points to a pool of surface intermediate species that are hydrogenated to HCN.     

氰化氢在终冷塔中气液两相之间转移的研究

分析了煤气中氰化氢的形成,论述了氰化氢在煤气和其冷凝液中的平衡机理,讨论了影响氰化氢相平衡的因素,研究了直接终冷、间接终冷时煤气中氰化氢的转移情况。     

Adsorption of HCN and H2O vapor mixtures by activated and impregnated carbons

Adsorption isotherms for HCN-H₂O vapor mixtures have been determined on BPL grade activated carbon and on ASC whetlerite (impregnated) carbon. The results show that the adsorption of HCN by carbons which are already in equilibrium with high levels of water vapor is significant. Adsorption of HCN strongly dominates when HCN and H₂O are simultaneously adsorbed from the vapor phase. Adsorbed HCN discourages additional adsorption of water vapor.     

A generalized relationship between the normalized yields of carbon monoxide and hydrogen cyanide

Experimental studies have demonstrated that there are close correlations between the normalized yields of carbon monoxide (CO) and hydrogen cyanide (HCN) from the combustion of materials containing nitrogen. In this paper, a generalized relationship using the stoichiometric oxygen to fuel mass ratio (SOFMR) is derived to represent these correlations. Using this generalized relationship, the predicted yields of HCN for nylon in tube furnace experiments and HCN concentrations in full‐scale cable fire tests are in good agreement with the corresponding measured data. The derived relationship is used to analyse the contributions of CO from different materials in a complex fire reconstruction. The generalized relationship is then used to predict HCN concentrations in two full‐scale nylon fires and the predicted concentrations are compared with both experimental data and predictions from a flamelet model. Finally, a method to incorporate the generalized relationship within CFD fire simulations to determine HCN (or CO) concentrations based on measurements of CO (or HCN) yields is presented. Copyright © 2010 John Wiley & Sons, Ltd.     

Formation of N-containing gas-phase species from char gasification in steam

The formation of N-containing products during char-steam gasification has been investigated in a laboratory scale fixed bed reactor. Experiments were conducted at 1000 °C, 0.1-1.0 MPa, and 6-46% of H₂O in He base flow. Two very different coal chars, which were prepared from the rapid heating of Australian bituminous and sub-bituminous coals, were studied. The nitrogen-containing products released during the gasification were measured using an FTIR spectrometer (NH₃, HCN and HNCO) and gas chromatography (N₂). The major N-containing products formed during char-steam gasification are NH₃, HCN and N₂. Reactions of HCN in the same reactor were also studied; these experiments were conducted with HCN alone, HCN/steam, and HCN/steam/char. The results are consistent with a mechanism in which HCN is the primary N-containing product of the char-steam reaction, and the additional products result from further reactions of HCN either in the gas phase or promoted by the surface of the reactor or the char. Increasing concentrations of steam significantly influence the distribution of char-N to N-containing gas-phase products, resulting in the increase of NH₃ at the expense of N₂. Some differences in char behaviour are also observed, particularly on the distribution of N-containing products at 0.1 MPa total pressure.     

简化的Solomon热解模型和旋流煤粉燃烧NO生成的数值模拟

提出一种简化的Solomon热解模型, 用于模拟煤粉燃烧NO生成数值模拟中HCN的释放.用纯双流体模型、k-ε-k_p两相湍流模型、EBU-Arrhenius燃烧模型、六热流辐射模型、双方程热解模型、简化的Solomon热解模型以及NO生成湍流反应二阶矩代数模型对旋流煤粉燃烧器内两相流动、煤粉燃烧、HCN释放以及NO生成进行了数值模拟.模拟结果与文献中实验结果的对比表明,基于简化Solomon热解模型的HCN释放模型预报结果比基于双方程热解模型的HCN释放模型预报结果好.     

Formation of NOx and SOx precursors during the pyrolysis of coal and biomass. Part III. Further discussion on the formation of HCN and NH3 during pyrolysis

The formation of HCN and NH₃ from the pyrolysis of coal (and biomass) is discussed based on our experimental data as well as the data in the literature, including the pyrolysis of N-containing pyrrolic and pyridinic model compounds reported in the literature. The pyrolysis of the model compounds and the thermal cracking of coal pyrolysis volatiles appear to be in good qualitative agreement in terms of the onset decomposition temperature, the main intermediates and the final N-containing product (HCN). The formation of NH₃ requires the presence of condensed phase(s) of carbonaceous materials rich in hydrogen. Direct hydrogenation of the N-sites by the H radicals generated in situ in the pyrolysing solid is the main source of NH₃ from the solid. The initiation of the N-containing heteroaromatic ring by radical(s) is the first step for the formation of both HCN and NH₃. While the thermally less stable N-containing structures are mainly responsible for the formation of HCN, the thermally more stable N-containing structures may be hydrogenated slowly by the H radicals to NH₃. The formation of NH₃ and the formation of HCN are controlled by the local availability of radicals, particularly the H radicals, in the pyrolysing solid. The increased yield of NH₃ (and HCN) with increasing heating rate can be explained by the rapid generation of the H radicals at high heating rates, favouring the formation of NH₃ (and HCN) over the combination of N-containing ring systems within the coal/char matrix. The size of the N-containing heteroaromatic ring systems and the types of substitutional groups also play important roles in the formation of HCN and NH₃.     

造气浊水循环回用过程中HCN对空气污染的讨论

利用大气扩散模式计算造气浊水冷却过程中冷却塔尾气中HCN扩菜的空间浓度分布及下风向地面最大浓度值，并讨论HCN对厂区空间大气质量及厂邻居民区大气质量的影响，提出相应防治措施。     

含氰化氢废气治理研究进展

氰化氢（HCN）是一种危害人体健康和大气环境的剧毒污染物,任何含氮物质和含氮燃料的燃烧、化工生产、冶金、汽车尾气排放等都能释放含HCN的废气。本文综述了近年来脱除HCN方面的研究进展,评述了各种脱氰方法包括吸收、吸附、燃烧、催化氧化、催化水解等技术的原理、适用对象及各种方法的优缺点。结果表明：吸收和燃烧法具有净化效率高、工艺简单等优点,对处理高浓度含氰废气有较大优势;其它方法的脱氰剂虽起活温度高、再生较为困难,但二次污染小,适用于气体的精细脱氰。今后各种技术的联合应用不仅能实现复杂气分下工业废气中HCN的逐级净化,而且能综合回收利用尾气中高浓度CO作为燃料和化工原料气。虽然各技术的联合应用在投资成本和工艺控制方面还有一定难度,但却具有较大的发展前景,是今后含氰化氢废气脱除的新趋势。     

神木煤热解形成NOx前驱物的影响因素研究

热解是煤加工的重要基础过程，它是煤燃烧、气化的初始和伴随反应。通过固定床石英反应器研究了不同的热解方式、加热速率、气体流速和粒径对神木煤形成NO，的前驱物HCN和NH3，的影响规律，得出以下结论：终温和加热速率越高，形成的HCN和NH，的量越大；粒径的变化对HCN和NH3的影响规律不同；气体流速对HCN和NH3的形成受加热方式的影响。