污泥水热处理过程中氮元素的迁移转化

采用高温高压反应釜在不同温度下进行了污泥水热实验。主要考察污泥中氮元素在水热过程中的迁移转化以及水热温度的影响,并对水热过程中氮元素的迁移路径进行了系统分析。结果表明,氮元素主要分布在固相和液相产物中,并随着水热温度的升高,分布在液相产物中的氮元素逐渐增加。在水热过程中,污泥中的无机氮形态几乎全部转换为氨氮和硝酸盐氮形态;不稳定性蛋白质氮分解为有机氮和氨氮,有机氮可进一步分解为氨氮;而稳定性蛋白质可转变为吡啶氮、吡咯氮、季氮以及腈氮形态,在较高的水热温度下均可再分解为氨氮。因此,随着水热处理温度的升高,污泥中氮元素逐渐从固相中转移到液相中,在液相产物中主要以有机氮和氨氮形态赋存。     

渣油在加氢处理中的氮分布和氮类型变化

采用氮分布和酸电位滴定分析技术对渣油在加氢处理中试装置上的氮含量及氮类型变化进行定量研究,结果表明：氮的总脱除率为42.36%,在上流式和固定床两个阶段的脱除率分别为26.76%和15.60%。焦化蜡油和减压渣油混合成的原料渣油的氮含量呈＂U＂型分布。随着加氢深度增加,芳香分中的氮含量降低,而胶质和沥青质中的氮含量增加。氮在渣油四组分中的分布规律是芳香分组分〉胶质组分〉沥青质组分。在加氢处理过程中,总氮、碱性氮和非碱性氮含量逐渐降低,但非碱性氮占总氮的质量分数呈降低趋势,而碱性氮占总氮质量分数呈增加趋势。     

石油化工常压及低压储罐的氮封系统设计

阐述合理设定氮封系统中各阀(氮封阀、泄氮阀、呼吸阀)的压力,可避免氮封失效。泄氮阀和氮封阀分别起"呼"、"吸"作用,呼吸阀仅起安全保护作用。分别从氮封系统适用工况、设计原则、供气量计算、注意事项等方面进行了详细阐述,通过对氮封系统的合理设计,可规避安全风险、降低事故概率。     

氮掺杂碳材料的制备及其化学活性位点研究

为了找出比较优异的非铂电极材料,并分析得出其最佳活性位点,分别从氮掺杂碳和碳载过渡金属氮材料催化剂在阴极催化的两个方向进行了探究。现如今通过X射线光电子能谱分析(XPS)可以检测出吡啶型氮、吡咯型氮和石墨型氮三种主要的氮掺杂活性位点。氮掺杂碳(G-N),氮掺杂碳纳米管(NCNT)以及氮掺杂石墨烯-氮掺杂碳纳米管(N-GO1@CNTs2)三种典型的氮掺杂碳材料进行分析。由此可见碳载过渡金属氮催化剂材料的催化活性位点很有可能主要是氮化金属化合物起作用。     

陶瓷前驱体聚硅氮烷的制备研究进展

综述了合成Si-C-N陶瓷前体聚硅氮烷的一些方法,着重介绍了含金属聚硅氮烷的制备方法,如:含钛聚硅氮烷、铝基聚硅氮烷、铁基聚硅氮烷、锆基聚硅氮烷、硼基聚硅氮烷、钇基聚硅氮烷、铜基聚硅氮烷的制备方法;其次介绍了使用共聚法、超支化法、倍半硅氮烷水解法制备聚硅氮烷的方法。     

肥料中各种形态氮的测定方法

论述了肥料中铵态氮、硝态氮、酰胺态氮和有机质氮等各种形态氮的测定意义,系统地介绍了肥料中各种形态氮的测定方法以及应用情况。     

硝态氮浓度对短程反硝化的反硝化速率影响研究

短程反硝化的反硝化过程是将水中的硝态氮反硝化控制在亚硝态氮阶段,亚硝态氮被直接还原成氮气的过程。硝态氮是亚硝态氮积累的来源,是影响短程反硝化过程的重要因素。通过改变硝态氮浓度,研究了不同浓度条件下的亚硝态氮的积累率,以及以短程反硝化的反硝化速率。结果表明,随着硝态氮浓度增加,亚硝态氮积累率先增大后趋于稳定,反硝化速率先增大再降低后趋于稳定,硝态氮浓度影响亚硝酸根积累率从而影响反硝化速率。实验采用双Monod方程模拟其反硝化过程动力学,根据方程可以预判不同硝态氮浓度下的反硝化速率。     

考察WSQ-5型脱氮剂在络合脱氮—白土精制工艺中的效果

以糠醛精制油和糠醛抽出油为原料,选用WSQ-5型脱氮剂,在实验室中进行络合脱氮—白土补充精制组合工艺试验,考察脱氮剂在该工艺中的脱氮效果。试验结果表明:WSQ-5型脱氮剂对氮含量较低的原料具有显著的脱氮效果,且主要是脱除原料中的碱性氮化合物。     

施氮量及控释氮比例对小麦定位效应研究

研究豫东潮土小麦适宜施氮量和控释氮施用比例。结果表明:小麦适宜的施氮量在210~285kg/hm~2,以施氮285 kg/hm~2的小麦产量和效益最高;小麦产量随控释氮比例的增加先增加后减少,以40%控释氮质量比例、施氮量210 kg/hm~2的处理较高。     

六元氮杂芳环构建方法及含能材料合成研究

综述了吡啶,哒嗪、嘧啶、吡嗪环、三嗪以及四嗪等六元氮杂芳环骨架构建方法,探讨了相应的六元氮杂芳环环化反应机理,概述了典型含能材料的物化与爆轰性能;重点从合成角度总结了缩合反应与环加成反应在构建六元氮杂芳环结构中的应用,讨论了在相应氮原子中心位点实现氮氧化或氮氨化反应的方式。其中,六元氮杂芳环氮氧化片段的引入主要包括两类途径：一是以氧化剂与氮杂芳环中氮原子中心发生反应,形成N-氧化物片段;另一类是利用环化反应,将相应的氮氧双键等结构转化为N-氧化物片段。附参考文献91篇。     

Reduction of nitrogen dioxide by propene over acidic mordenites: influence of acid site concentration, formation of by-products and mechanism

The reduction of nitrogen dioxide to nitrogen by propene was studied over a variety of acidic mordenite zeolites differing in their Si : Al ratio and thus, in their concentration of acid sites. The formation of by-products was monitored applying an ion–molecule reaction (IMR) mass spectrometer. It was found that at fixed conditions the yield of nitrogen increases with increasing concentration of acid sites, confirming that acid sites are the active catalytic centres in the reaction. Apart from nitrogen and nitric oxide, acrylonitrile and ammonia are formed as nitrogen containing gas-phase products in the reaction. In separate experiments, it was shown that acrylonitrile is hydrolysed by water over the acidic zeolites to yield ammonia and acrylic acid. When acrylonitrile is used as reducing agent for nitrogen dioxide, formation of nitrogen is strongly enhanced in the presence of water. Water also has a promoting effect on the formation of nitrogen in the reaction between nitrogen dioxide and propene. Acrylonitrile and its product of hydrolysis, ammonia, are considered to be intermediates of nitrogen dioxide reduction to nitrogen by propene over acidic zeolites.     

Miniaturized method for separation and quantification of nitrogen species in petroleum distillates

The properties of nitrogen compounds are a subject of interest to petroleum refiners due to the detrimental role, these compounds play in catalyst deactivation and product stability. It is thought that basic nitrogen is a major contributor to these phenomena, and therefore identification and quantification of nitrogen species by type would be of great importance.A practical miniaturized method for quantitative separation of nitrogen compounds by type in petroleum distillates is described. Solid phase extraction methodology was used to concentrate the nitrogen compounds and to separate them further into neutral and basic types. The basic nitrogen compounds could not be fully recovered, while full recovery was achieved for the neutral nitrogen types. The amount of basic nitrogen was calculated by difference, and boiling point distribution profiles were produced. For identification of nitrogen compounds in separated fractions, a combined GC-MS/AED method with retention time locking was used. Carbazole and its substituted derivatives methyl, dimethyl, and trimethylcarbazoles were identified in the product from fluid catalytic cracking.     

相对压强对白炭黑氮吸附表面积测试稳定性的影响

研究相对压强对白炭黑氮吸附表面积测试稳定性的影响。结果表明:在相同液氮纯度、脱气温度、脱气时间、氮吸附点数量条件下,与相对压强范围为0.05~0.1时相比,相对压强范围为0.05~0.2时白炭黑的氮吸附表面积测量值偏低,且差值随氮吸附表面积的增大呈增大趋势;相对压强范围较小时,氮吸附表面积测试结果的线性相关因数较大,再现性较好,测试结果较稳定。     

Removal of nitrogen compounds from lubricating base stocks with complexing of oxalic acid

A new method to remove the nitrogen compounds from lubricating base stocks was revealed by using the complexing and crystallization of oxalic acid and nitrogen compounds in this paper. The data indicated that the reaction and filtration temperatures obviously influence the nitrogen removal efficiency. The suitable reaction temperature was 100–130 °C and the reaction time is more than 20 min. The crystal water in oxalic acid can lower the removal efficiency, which can be improved when inert gas is introduced to take out the crystal water in oxalic acid. When clay was used in the reaction system, the nitrogen removal efficiency was improved and the filtration temperature was also elevated. Oxalic acid can remove more than 98% of basic nitrogen compounds and more than 70% of nonbasic nitrogen compounds from the lubricating base stocks. The removal of basic nitrogen showed a linear relationship with the removal of nonbasic nitrogen.     

悬浮填料床同步硝化反硝化脱氮试验研究

在好氧条件下,向反应器中装填悬浮填料进行脱氮试验,考察生物膜法对氨氮和总氮的去除效果.结果表明：DO为3.0 mg.L-1时,氨氮平均去除率达到89.52％、总氮平均去除率达到29.46％.在好氧条件下,生物膜脱氮效果明显,硝酸盐氮的积累使反硝化过程成为脱氮的制约因素之一.     

Nitrogen functionality in coals and coal-tar pitch determined by X-ray photoelectron spectroscopy

The forms of nitrogen in several Australian coals, a coal-tar pitch, mesophase prepared from the coal-tar pitch, and the isotropic phase in equilibrium with the mesophase, have been determined by X-ray photoelectron spectroscopy. In agreement with previous studies, nitrogen in the coals was found to be present predominantly in pyrrolic and pyridinic forms, with the proportion of pyrrolic being greater than pyridinic in each case. A N(1s) component near 401.5 eV was assigned to a protonated or oxide form of pyridinic nitrogen. On this basis, the total proportion of pyridinic nitrogen is comparable with the reported value determined by X-ray absorption near-edge structure spectroscopy for a US bituminous coal. Pyrrolic nitrogen was also found to be the predominant form of nitrogen in coal-tar pitch. The nitrogen content, and the ratio of pyrrolic to pyridinic functional forms, were essentially the same in coal-tar pitch mesophase as in the precursor pitch from which it was prepared. It was concluded that mesogens do not discriminate against the inclusion of nitrogen in 5- or 6-membered rings, but that other nitrogen functionalities such as amines appear to be excluded.     

沸石-炭复相材料对氨氮吸附性能研究

研究以沸石粉为主要原料,添加木屑、淀粉等有机物为碳化结合剂,通过造粒、氮气气氛低温热处理制备得到了粒度为0.5~1 cm的沸石-炭复相材料水处理剂颗粒,研究了不同碳化结合剂含量和不同热处理温度等氨氮超标污水的吸附性能影响。采用场发射扫描电镜对沸石-炭复相材料进行了显微形貌观察。通过氨氮吸附实验得出,相同质量条件下沸石-炭复相材料水处理剂颗粒在吸附速率上弱与沸石粉体,在足够吸附时间下对氨氮的吸附量同沸石粉体吸附量接近。5%碳化结合剂添加量样品有最优氨氮吸附性能,起始浓度为15 mg/L氨氮溶液被吸附24 h后氨氮溶液浓度降为4.69 mg/L,氨氮吸附量为1.03 mg/g;吸附100 h后氨氮溶液浓度降为1.35 mg/L,氨氮吸附量为1.36 mg/g。     

浮法生产线空分设备增产降耗改造

通过对现有空分设备进行改造,提高氮气产量,并对相关管道进行联网,用二线一套制氮机组供应浮法一线锡槽用氮气,用二线另一套制氮机组再加上原一线一套制氮机组供应二线锡槽用氮气,与改造前相比少开启一套制氮机组.以达到节约氮站电耗和备件消耗,同时提高二线氮气提取率的目的.     

Determinants of nitrogen surplus at farm level in Swiss agriculture

This paper investigated the determinants of nitrogen surplus, also denoted as nitrogen balance, at farm level in Swiss agriculture. Our analysis was based on a cross-section of 210 farms from the year 2010. The nitrogen surplus of each farm was estimated according to the OECD soil-surface approach and decomposed in two components—nitrogen intensity and nitrogen inefficiency. The average nitrogen surplus of the farms investigated amounted to 89 kg/ha, resulting from an average nitrogen intensity of 255 kg/ha and an average nitrogen inefficiency of 34%. The determinants of nitrogen surplus and its two components were analyzed by means of a three-equation regression model estimated using a robust seemingly unrelated regression approach. Farm size, part-time farming, organic farming, arable cropping and farmer’s age were found to decrease nitrogen surplus, whereas dairy, pig and poultry farming were associated with an increase in nitrogen surplus.