SO2 Reactions over γ-Al2O3,Pt/γ-Al2O3,Sn/γ-Al2O3 and Pt–Sn/γ-Al2O3

Platinum and Platinum–tin bimetallic catalysts supported on alumina were prepared by co-impregnation of both metallic precursors on the support and used as catalysts for the oxidation of SO₂. Platinum dispersion was determined by means of H₂–O₂ titration. Tin addition (1 and 2 wt%) only slightly decreased the exposed platinum atoms suggesting that tin is mainly over the support. At temperatures lower than 300 °C, SO₂ did not react with oxygen. Nevertheless, when the temperature was increased, the SO₂ oxidation began. The ignition temperatures for SO₂ oxidation (taken at 50% conversion) were 345 °C for 1% Pt/Al₂O₃ and 520 °C for 1% Pt–2% Sn/Al₂O₃. The strong displacement on activity suggests that tin plays an important role as inhibitor of the SO₂ oxidation reaction.     

Mixed mode crack propagation of homogenized cracks by the two-dimensional DDM analysis

The crack propagation process in rock mass is numerically estimated by two-dimensional stress analysis. Rock mass typically contains numerous cracks within, with varying extent and orientation. In order to analyze the mechanical interaction of cracks, the homogenization method is introduced too in this study. In the analysis, SC-DDM (stress compensation-displacement discontinuity method) and DDCM (displacement discontinuity comparison method) are applied to the crack homogenization model, and the stress intensity factors are calculated. Then the crack propagation of the model is analyzed, using the maximum circumferential stress criterion. The influences of the mechanical interaction between cracks to the crack propagation is discussed.     

10 MN龙门剪切机液压系统设计及剪切回路仿真分析

为了提高现有废钢剪切机工作效率低、剪切频率慢等问题,在原有龙门剪的基础上设计10 MN龙门剪切机液压系统。此次设计采用了多泵耦合系统,以及间歇和连续供油相结合的方式和各剪切动作转换无时间间隔的控制方式,并用AMESim对剪切回路液压系统进行仿真分析。仿真结果显示:施加10 MN负载,除了剪切机在动作转换时液压缸流量有一定的波动外,剪切频率比原来提高了22.1%,系统的压力和流量均满足要求。     

Influence of wet and preheated coal charging on the nature of quinoline insolubles of coal tars and their derived pitches

Differences between primary quinoline insoluble (QI) material of coal tars and their derived pitches caused by preheating carbonization have been studied using microscopic techniques, Coulter Laser particle size analysis and solid-state ¹³C NMR. The selected tars were produced from the same coal using wet and preheated charging at the INCAR experimental coking test plant, which operates on a semi-industrial scale. Specific operational conditions were successfully applied not only to reduce the ash content and the QI and toluene insoluble (TI) contents in the tars produced by the preheating process, but also to modify the nature of the QI particles. In addition, structural changes in the insoluble materials formed during the pitch production from the tar have been monitored.     

高温三轴应力下无烟煤、气煤煤体渗透特性的试验研究

利用自主研制的600℃20MN伺服控制高温高压岩体三轴试验机系统,分别研究大尺寸(φ200mm×400mm)晋城无烟煤和兴隆庄气煤试样在恒定500m原岩应力(侧压系数1.2)条件下不同温度时渗透特性的演化规律。结果表明:(1)在室温～300℃中低温段,煤体渗透率随温度的变化存在一个阈值温度。当温度达到阈值温度时,渗透率降至最低值。(2)在300℃～600℃高温段,煤体渗透率随温度的变化存在一个峰值温度,峰值温度处渗透率为该温度段内的最大值。(3)煤体渗透率随温度的变化呈现阶段性:室温至阈值温度为第一阶段,渗透率随温度的增加而降低;阈值温度至峰值温度为第二阶段,渗透率随温度的升高而增加;高于峰值温度后,渗透率随温度的增加而降低。(4)渗透率随温度变化的阈值温度和峰值温度与煤阶有关。无烟煤渗透率的阈值温度是150℃～200℃,峰值温度为450℃～500℃,而气煤渗透率的阈值温度为200℃～250℃。     

Gasification of coking wastewater in supercritical water adding alkali catalyst

In this study, the influence of alkali precipitation on the gasification of coking wastewater with KOH as catalyst at 540 °C, 25 MPa was investigated. Adding the KOH increased H₂ fraction and the gas yield. The alkali is accumulated in the reactor, and the catalytic effect was further improved with reaction time prolonging. The precipitated alkali in the reactor still showed high catalytic effect on the subsequent gasification of coking wastewater without further adding the alkali. The catalytic activity was slightly reduced owning to the transformation of KOH to K₂CO₃ and KHCO₃. A novel 4-lump kinetic model for coking wastewater in SCWG including feedstock, CH₄, CO, and CO₂ lumps is proposed. The kinetic parameters are estimated for each involved reaction.     

FOM网络管理系统设计

本文介绍FOM及FOM组网的同时,具体阐述网络管理系统的设计思想,采用基于SNMP的网络管理系统设计方法-M/A模型,给出了软件的总体设计结构,针对管理站和代理,分别讨论了其数据的打包过程,发送、接收数据报文过程,信息的解析过程,以及它们的软件设计结构.