Numerical study on laminar burning velocity of ammonia flame with methanol addition

The combustion characteristics of ammonia/methanol mixtures were investigated numerically in this study. Methanol has a dramatic promotive effect on the laminar burning velocity (LBV) of ammonia. Three mechanisms from literature and another four self-developed mechanisms constructed in this study were evaluated using the measured laminar burning velocities of ammonia/methanol mixtures from Wang et al. (Combust.Flame. 2021). Generally, none of the selected mechanisms can precisely predict the measured laminar burning velocities at all conditions. Aiming to develop a simplified and reliable mechanism for ammonia/methanol mixtures, the constructed mechanism utilized NUI Galway mechanism (Combust.Flame. 2016) as methanol sub-mechanism and the Otomo mechanism (Int. J. Hydrogen. Energy. 2018) as ammonia sub-mechanism was optimized and reduced. The reduced mechanism entitled ‘DNO-NH3’, can accurately reproduce the measured laminar burning velocities of ammonia/methanol mixtures under all conditions. A reaction path analysis of the ammonia/methanol mixtures based on the DNO-NH3 mechanism shows that methanol is not directly involved in ammonia oxidation, instead, the produced methyl radicals from methanol oxidization contribute to the dehydrogenation of ammonia. Besides, NO_x emission analysis demonstrates that 60% methanol addition results in the highest NO_x emissions. The most important reactions dominating the NO_x consumption and production are identified in this study.     

乙烯齐聚催化剂研究进展

乙烯齐聚是合成直链低碳α-烯烃最先进的方法，直链低碳α-烯烃可用于生产低密度聚乙烯和高密度聚乙烯等多种精细化学品。本文综述了乙烯齐聚催化体系的研究进展，重点介绍了镍、锆、钛催化剂的组成以及反应时间、反应温度、溶剂、助催化剂等因素对乙烯齐聚活性和选择性的影响，并讨论了典型镍的催化机理。     

用晶种技术解决低品位石灰石配料中存在的问题

采用晶种技术，能有效地改善熟料的煅烧过程和熟料的质量。晶种和复合矿化剂的作用机理不同，在某些方面具有互补性。     

Influence of a lipid phase on steam jet agglomeration of maltodextrin powders

The contribution of an oil phase to the agglomeration mechanisms of food powders was evaluated. Maltodextrin (DE 10), palm oil stearin and two palm oil oleins (up to 25% dry mass) were used as food models. Granulation runs were carried out in a pilot plant steam jet agglomerator. The powders containing oleins were more cohesive than those with stearin and the presence of oil changed the agglomeration mechanisms. The size increase mechanism of pure maltodextrin powder was controlled by surface plasticization and agglomerates with suitable instant properties were obtained. Small amount of oil degenerated drastically the rate of dispersion in water of the powders and their agglomerates but the average size and the mechanical resistance of the agglomerates increased when the oil content of the powders increased. SEM micrographs of agglomerates indicated that higher lipid content in the powders produced compact granules, favoring sinkability but hindering their disintegration. Agglomeration enhanced considerably the flowability of the particles containing oil. The dispersion behavior of the powders with higher lipid content could be correlated with the Hausner Number. A pre-agglomeration step favored the blend of the more cohesive powders producing larger and more resistant agglomerates.     

岩土体斜(边)坡滑坡发生的机理

根据滑坡发生的初始条件、滑坡成因及方式表象,对常见的蠕变倾覆滑坡、卸荷滑坡、震动液化平推滑坡、潜蚀塌陷滑坡、溶蚀下陷滑坡、孔隙水压浮动滑坡和人工切蚀或冲(浪)蚀—加载滑坡等机理进行了分析.     

糖厂现用连续离心机的研究及生产实践

在各糖厂现用连续离心机原有生产实践基础上，对其机械吸震、加温、布温、机索结构、物料密封、机座等部件做了进一步改进，并取得可观的实效。     

关于中小型勘察设计单位转企改制问题的探讨

本文针对中小型勘察设计单位存在的所有制形式单一,经营方式落后,队伍结构不合理,负担过重,内部机制不活,抵御风险能力差等问题,阐述了改制的重要性和紧迫性,提出了建立适应社会主义市场经济要求的工程勘察设计管理体制和运行机制.     

阻燃沥青的研究进展与建议

介绍了对沥青进行阻燃处理的必要性、沥青的阻燃机理、常用阻燃剂的特性及其作用模式;参照塑料材料阻燃性能的测试手段介绍了常用的沥青材料阻燃性能的测试方法;最后分析了我国沥青阻燃的研究现状,指出了该领域存在的主要问题,并给出了相应的建议。     

石蜡光氯化合成氯蜡－70的研究──（Ⅲ）反应过程致色因素考察及生色机理研究

氯蜡－７０是—应用广泛、性能优良的精细化工产品，其色泽是—重要的技术指标，直接影响着产品的质量和应用。本文考察了合成反应过程导致生色的因素，指出原料中含有的少量环烷烃、芳烃、杂环有机物及少量无机杂质能影响产品的色泽，实验表明温度过高，光源波长选择不当也是致色的重要原因。研究了致色的过程，提出其生色历程是按照β－消除反应机理进行的，并做了具体描述。     

环氧油一步合成的反应机理和动力学研究

研究了环氧油一步合成的反应机理和动力学；结合实验结果和理论分析动力学模型，首次提出：在适当的反应条件下，油脂的一步环氧化反应动力学模型可以表示为过氧酸生成反应动力学模型；其实验动力学模型方程为：ｒ０＝ｋ［Ｈ２Ｏ２］（０．９９）［ＨＯＡｃ］（０．９７），其中ｋ与催化剂用量有关。