三元催化器损坏的批量分析

随着三元催化器在乘用车上的广泛使用,三元催化器引起的车辆后处理系统故障并不鲜见。本文通过与整车厂合作,批量分析了售后市场返回的135件三元催化器故障件,对故障类型进行分类后,有针对性的对部分故障零件进行了实验室分析。证明了三元催化器的损坏主要来自催化器封装缺陷、中毒和高温失火。其中催化器中毒和高温失火烧熔在前级催化剂较容易发生,而后级催化器的损坏大多来自封装缺陷造成的机械损坏。     

香菇鸡肝风味肠的研制

本文以猪肉为主要原料,研究猪肉与香菇、鸡肝的配比,肥瘦比例以及淀粉添加量对猪肉香肠品质风味的影响.利用单因素实验及正交试验与感观评定确定其主要原料的最佳配方:猪肉肥瘦比为1:6、香菇添加5 %、鸡肝的添加量2 %、淀粉添加量6 %.此工艺参数可研制出色泽红润、均匀,组织状态良好,香味纯正浓郁,外形完整的香菇鸡肝风味香肠.     

催化裂化催化剂铁中毒现象分析与解决方案

催化裂化作为最重要的原油二次加工手段之一,是炼厂生产轻质油品、提高经济收入的关键装置.催化装置的稳定运行直接影响炼厂的经济效益.针对某炼厂催化装置出现产品分布变差的问题,从原料性质、平衡剂性质、平衡剂评价等几方面进行了系统分析,结果表明是由催化原料铁离子含量过高引起的平衡剂重金属中毒.通过提高反应温度,降低加工量,提高...     

Deactivation of hydrodesulfurization catalysts during reactor startup

Metal sulfide catalysts for ultra-deep hydrodesulfurization of diesel generally lose a fraction of their catalytically active sites during reactor startup. The underlying mechanisms are discussed. A laboratory diagnostic tool consisting of three probe molecules is developed for testing metal sulfide catalysts' start-of-run (SOR) activity maintenance. It is found that a significant fraction of the active sites on a commercial supported catalyst are deactivated permanently, but this is not the case with a bulk metal sulfide catalyst. The SOR deactivation of the bulk catalyst is completely reversible, while that of the supported catalyst is partially reversible. The diagnostic tool may provide a basis for developing a high-throughput approach for evaluating and enhancing catalyst SOR stability, thereby increasing plant productivity.     

催化裂化催化剂铁污染研究进展

介绍近年关于FCC催化剂铁中毒现象的研究进展。平衡剂上铁存在新鲜催化剂自身铁、原油原有铁和过程铁3个来源,其中,高酸原油的过程铁含量已不容忽视。催化裂化过程中,原料油中以环烷酸铁为主的铁物种不断沉积在催化剂的表面,与催化剂中的钠、氧化硅形成低熔点共熔物,形成覆盖平衡剂表面的光滑结构,堵塞催化剂的孔道,导致汽油产率下降,严重影响装置稳定运行。根据铁中毒的机理研究,提出加强人员技术交流与培训、提高分析检测频次、应用抗铁污染催化剂、铁中毒解决方案等预防和应急措施,为加工高铁含量原料油催化裂化装置的长期稳定运行提供技术参考。     

Oxidation of CO on hydrogen-loaded palladium

The oxidation of CO adsorbed on the surface of palladium electrodes loaded with different amounts of hydrogen was studied by single potential alteration infrared reflectance spectroscopy (SPAIRS). In the absence of hydrogen, only CO₂ was detected during anodic oxidation of CO. Adsorption of CO in the presence of hydrogen in palladium led to a more negative onset of its electrooxidation, and the formation of other products, such as ethanol and formaldehyde, as well as CO_{_2}. The results indicate that hydrogen occluded in palladium contributes to the displacement of carbon monoxide from the interface; this may assist in the continual electrooxidation of organic compounds at palladium electrodes.     

Optimization of Microwave-Vacuum Drying of Button Mushrooms Using Response-Surface Methodology

Button mushrooms (Agaricus bisporous) were dried in a microwave-vacuum dryer up to a final moisture content of around 6% (d.b.). The effect of microwave power level (115 to 285 W), system pressure (6.5 to 23.5 kPa), and slice thickness (6 to 14 mm) on drying efficiency and some quality attributes (color, texture, rehydration ratio, and sensory attributes) of dehydrated mushrooms were analyzed by means of response surface methodology. A rotatable central composite design was used to develop models for the responses.Analysis of variance showed that a second-order polynomial model predicted well the experimental data. The system pressure strongly affected color, hardness, rehydration ratio, and sensory attributes of dehydrated mushrooms. A lower pressure during drying resulted in better quality products. Optimum drying conditions of 202 W microwave power level, 6.5 kPa pressure, and 7.7 mm slice thickness were established for microwave vacuum drying of button mushrooms. Separate validation experiment was conducted at the derived optimum conditions to verify the predictions and adequacy of the models.     

Hydrogen sulfide poisoning and recovery of PEMFC Pt-anodes

A simple and effective method for reactivation of H₂S poisoned Pt-anodes is described and the feasibility of the method was examined by single cell tests and 1 kW stack tests. The performance of the H₂S poisoned Pt-anode can be basically recovered by applying a high voltage pulse (1.5 V for 20 s) followed by a low voltage pulse (0.2 V for 20 s) in a single cell. During the 10 poisoning–recovery cycles, the ohmic resistance and electrochemical surface area did not change significantly. The 1 kW stack tests show that the stack performance decayed severely and the maximum power decreased to 0.366 kW (32% of the original value) after exposure to 18 ppm H₂S/H₂ for 2 h at 600 mA cm⁻². The stack performance can be significantly recovered by applying a high voltage pulse (1.5 V for 2 min) followed by a low voltage pulse (0.2 V for 2 min) to each cell. The maximum power recovered to 1.095 kW (97.5% of the original value).     

中国农药急性中毒致因探讨

目前农药急性中毒已成为世界各国共同关注的社会问题.中国为控制农药污染,防止农药中毒,加强了农药管理,完善了法律法规,但农药急性中毒的形势并未得到有效扼制.通过对近年来中国农药中毒情况的统计分析,揭示了中国农药急性中毒的主要致因和特征:中国每年发生农药急性中毒病例约5万人,死亡数千人.其中生产性农药中毒者约1万人,病死率不足1%;非生产性农药中毒者约4万人,病死率约10%.显然非生产性农药急性中毒是构成农药中毒的主要原因.生产性农药急性中毒主要发生在农村第三季度,年龄以30～50岁居多,且男性多于女性.非生产性农药急性中毒主要是由于家庭纠纷等原因引起的服毒自杀,约占非生产性农药急性中毒的80%,高发年龄段提前到20～40岁,且女性高于男性.因此防止农药急性中毒的重点是构建和谐的家庭和社会.     

长江中下游地区层控矽卡岩型铜矿床控矿地质因素新探

从物理化学流体动力学角度出发，结合野外调研及资料分析，作者认为长江中下游地区层控矽卡岩型铜矿床的形成主要是特定的透水─不透水地层系统、Ｓ形褶皱构造及蘑菇状岩体三者协调作用的结果。这一认识为本地区寻找此类矿床提供了直接的找矿依据。