Selective catalytic reduction of NOx by hydrocarbons on Pt/Al2O3 catalysts at low temperatures without the formation of N2O

The selective reduction of nitrogen oxides by hydrocarbons on a Pt catalyst has been investigated. Some variations are observed between different reductants. However, the most significant result is the observation that no N₂O is observed as a by-product when toluene is used as a reductant.     

Reactivity of steam in exhaust gas catalysis III. Steam and oxygen/steam conversions of propane on a Pd/Al2O3 catalyst

A 1% Pd catalyst (38% dispersion) was prepared by impregnating a γ-alumina with palladium acetylacetonate dissolved in acetone. The behaviour of this catalyst in oxidation and steam reforming (SR) of propane was investigated. Temperature-programmed reactions of C₃H₈ with O₂ or with O₂ + H₂O were carried out with different stoichiometric ratios S(S =[O₂]/5[C₃H₈]). The conversion profiles of C₃H₈ for the reaction carried out in substoichiometry of O₂ (S < 1) showed two discrete domains of conversion: oxidation at temperatures below 350°C and SR at temperatures above 350°C. The presence of steam in the inlet gases is not necessary for SR to occur: there is sufficient water produced in the oxidation to form H₂ and carbon oxides by this reaction. Contrary to what was observed with Pt, an apparent deactivation between 310 and 385°C could be observed with Pd in oxidation. This is due to a reduction of PdO_x into Pd⁰, which is much less active than the oxide in propane oxidation. Steam added to the reactants inhibits oxidation while it prevents the reduction of PdO_x into Pd⁰. Compared to Pt and to Rh, Pd has a higher thermal resistance: no deactivation occurred after treatment up to 700°C and limited deactivation after treatment up to 900°C, provided that the catalyst is maintained in an oxygen-rich atmosphere during the cooling.     

橡塑共混热塑性弹性体的形态结构与性能

综述了影响共混热塑性弹性体的形态结构与性能的主要因素。     

壳聚糖／聚丙烯酸钠聚离子复合膜的醇－水渗透汽化分离性能

研究了壳聚糖－醋酸溶液与聚丙烯酸钠溶液形成的复合膜用于水－乙醇混合物的渗透汽化分离，在膜组成Ｃ＝０．８０时，分离系数出现最大值，对异丙醇－水体系的分离系数为∞。溶解－扩散过程对渗透汽化过程起着重大作用。由－ＮＨ＋３…ＯＯＣ－交联的聚离子复合膜对醇－水体系具有稳定的分离性能。     

贝利阀在氨厂运行情况简介

介绍贝利阀在试车及试生产期间出现的问题及解决办法，指出维护过程中应注意的事项。     

国产活性炭在合成气净化中的应用

选择国产Ｋ０１活性炭脱除羰基铁、镍，以达到保护铑催化剂并减少副产物的目的。１年的实际应用结果表明：国产Ｋ０１活性炭能够替代进口活性炭在合成气净化中应用。     

可编程控制器在化肥散运系统上的应用

整个散运系统采用３台ＦＸ２－１２８ＭＲＰＬＣ分块控制后，使得控制结构清楚，线路简单，工作可靠性大为提高，对所有控制柜元器件进行数据库管理，极大地提高图表的准确率。     

电子自旋共振在橡胶研究中的应用

综述了电子自旋共振在橡胶的合成、加工和应用领域的应用现状及其发展前景。     

NH_4Cl水溶液在成膜过程中的致孔作用

本文以ＮＨ４Ｃｌ饱和水溶液做添加剂，对ＰＶＤＦ／ＮＭＰ体系在成膜过程中的致孔作用做了研究。铸膜液中随ＮＨ４Ｃｌ水溶液加入量的改变，膜孔径也发生变化，并出现最大值。通过Ｘ－射线衍射扫描发现制膜液中存在无机盐时膜中无定形态结构增加，表明无机盐的加入有助于膜孔形成     

光纤压力传感器微机控制与数据处理系统

本文介绍的光纤压力传感器微机控制与数据处理系统是以8098单片机为核心,配上适量的外围电路所构成。该系统直接利用8098单片机芯片内的A/D模拟输入通道和脉宽调制(PWM)功能来进行数据采集和输出控制信号。该系统还方便地实现与微型打印机的联接,以便将采集的数据保存。整个系统结构简单,成本低,可靠性高,实时控制和测试功能较强,有良好的工业应用价值。