Effects of synthesis methods on the performance of Pt + Rh/Ce0.6Zr0.4O2 three-way catalysts

The 0.7 wt% Pt + 0.3 wt% Rh/Ce0.6Zr0.4O2 catalysts were fabricated via different methods, including ultrasonic-assisted membrane reduction(UAMR) co-precipitation, UAMR separation precipitation, co-impregnation, and sequential impregnation. The catalysts were physico-chemically characterized by N2 adsorption, XRD, TEM, and H2-TPR techniques, and evaluated for three-way catalytic activities with simulated automobile exhaust. UAMR co-precipitation- and UAMR separation precipitationprepared catalysts exhibited a high surface area and metal dispersion, wide λ window and excellent conversion for NOx reduction under lean conditions. Both fresh and aged catalysts from UAMRprecipitation showed the high surface areas of ca. 60–67 m2/g and 18–22 m2/g, respectively, high metal dispersion of 41%–55%, and small active particle diameters of 2.1–2.7 nm. When these catalysts were aged, the catalysts prepared by the UAMR method exhibited a wider working window(Δλ = 0.284–0.287) than impregnated ones(Δλ = 0.065–0.115) as well as excellent three-way catalytic performance, and showed lower T50(169.C) and T90(195.C) for NO reduction than the aged catalysts from impregnation processes, which were at 265 and 309.C, respectively. This implied that the UAMR-separation precipitation has important potential for industrial applications to improve catalytic performance and thermal stability. The fresh and aged 0.7 wt% Pt + 0.3 wt% Rh/Ce0:6Zr0:4O2 catalysts prepared by the UAMR-separation precipitation method exhibited better catalytic performance than the corresponding catalysts prepared by conventional impregnation routes.     

生产工艺条件对菌粉爆炸特征参数的影响

利用扫描电镜及激光粒度分析仪,探究了不同生产工艺条件下医药中间体菌粉A和菌粉B的表面形状及粒径分布,并进行了热解分析,证实上述特征参数存在一定差别。在此基础上进行了爆炸特性参数研究。研究结果表明,上述两种菌粉爆炸下限处于70~90 g/m3,最大爆炸压力峰值0.4~0.5 MPa之间,爆炸性相对较弱,但也必须引起足够的重视。与菌粉B相比,菌粉A相对安全,因此条件许可时优先采用菌粉A生产工艺流程。     

某火电厂FGD工艺及其运行现状分析

某火力发电厂FGD系统采用石灰石/石膏湿法脱硫工艺,FGD系统中设置有旁路挡板,在正常运行时,其脱硫效率可以达到90%以上,二氧化硫排放低于400 mg/m3,达到国家排放要求。FGD系统运行中异常主要表现在原烟气SO2浓度超标,增压风机、GGH、吸收塔除雾器等设备易发生故障,导致脱硫效率下降,不能够达标排放,在设备运行过程中应注意防范。     

Determining distribution of heavy metal pollution in terms of ecological risk levels in soil of industrially intensive areas around Istanbul

The aims of the present study were to measure the concentrations of As, Cr, Co, Fe, and Zn in soils from two heavily industrialized areas and to assess the degree of heavy metal pollution by using the indices enrichment factor and the geo-accumulation index, as well as assessing the potential ecological risk. The concentrations of the selected elements in the environmental samples were determined by the neutron activation analysis. The pollutant concentrations in the studied areas showed that the soils were characterized by a high pollution from As and Cr due to the industrial facilities in the area. The concentrations in the Tuzla industrial area were 79–1215 mg/kg of Cr, 17–84 mg/kg of As, 22,000–54,000 mg/kg of Fe, 101–258 mg/kg of Zn, and 8–23 mg/kg of Co. The results for the Cerkezkoy industrial area were found to be 46–196 mg/kg of Cr, 6–24 mg/kg of As, 17,000–25,000 mg/kg of Fe, 67–136 mg/kg of Zn, and 7–10 mg/kg of Co. The contamination in the soils from heavy metals was assessed based on enrichment factor, geo-accumulation factors, and ecological risk indices. The results were compared with the data from other industrial areas in Turkey. It was found that the metals As and Cr showed higher concentrations in Tuzla than in other examined industrial areas. The results for Cerkezkoy industrial area indicate that the area is not as contaminated as the other industrial areas in Turkey.     

热电厂热储系统的构建和优化研究

热电厂热储系统的构建,对于废弃能源存储和废水再利用有重要意义。以吉林省桦甸市热电厂为例,通过对研究区水文地质条件和温度参数概化,利用FEFLOW软件构建桦甸市热电厂地下水-热耦合模型,用实际观测资料进行识别和验正,初步构建热储系统模型。设置不同井间距和抽水量来优化热储模型,研究结果表明:200 m井间距热贯通严重,500 m和1 000 m热贯通影响小;1 500 m~3/d的流量比1 200 m~3/d的流量在提热期温度下降更快,但提热总量显著增加;各方案提热总量对比显示,优化储热方案为井间距离500 m,储热期注水量8 400 m~3/d,热提取期抽水量1 500 m~3/d,冷水抽注水井在储热期和热提取期水量均为1 200 m~3/d,提热总量为2.27×10~(11)J/d。     

印染集控区内导热油炉中温中压蒸汽改造环境效益分析研究

"十二五"期间,石狮市实施了印染集控区内导热油炉的中温中压蒸汽改造工程,作为大气污染防治控制,保障城市空气质量的重点工作之一.以石狮市印染集控区内导热油炉中温中压蒸汽改造为研究对象,应用排放系数和物料守恒法对工程实施前后区域污染物削减情况进行测算分析.研究表明,实施工程后,石狮市印染集控区SO2、粉尘、NOx等污染物的排放量分别下降了82.1%、48.3%和62.8%,实现了大气环境质量的改善.     

铝合金表面阳极化层环境损伤失效行为研究

目的研究7B04铝合金硫酸阳极化层环境作用下的失效行为,分析单独盐雾试验和环境谱作用下阳极化层的损伤行为和影响因素。方法通过中性盐雾试验和环境谱周期性试验(盐雾试验+温度试验)研究了硫酸阳极化层在不同腐蚀时间或不同腐蚀周期下的腐蚀损伤变化过程,并采用体视显微镜和扫描电子显微镜(SEM)观察了不同腐蚀时间下或不同腐蚀周期下的表面形貌,结合有限元方法研究了阳极化层与铝合金基体热膨胀系数不匹配引起的热应力,定量分析了热应力对阳极化层失效行为的影响。结果经历中性盐雾试验和环境谱试验的硫酸阳极化层损伤失效现象是不一样的,中性盐雾试验中硫酸阳极化层主要呈鼓起开裂失效,而环境谱试验中硫酸阳极化层以开裂剥落失效为主。结论中性盐雾试验中硫酸阳极化层主要是腐蚀介质通过表面微孔进入基体,导致基体腐蚀阳极化层鼓起,而环境谱试验因温度作用产生的热应力引起了硫酸阳极化层的开裂,形成了腐蚀介质进入基体的通道,引起阳极化层的剥落。     

基于热网络模型的导弹贮存温度预计方法

目的提供一种预计空空导弹的外场贮存温度的方法,以确定空空导弹的环境适应性要求。方法基于热网络模型,预计不同环境条件下导弹的贮存温度与日高温极值。考虑各种环境因素对导弹热环境的综合影响,建立导弹内外各节点的能量守恒方程。将实测数据代入方程,利用最小二乘法拟合方程系数建立预计模型,将实测结果与模型的预计结果进行对比以验证模型的准确性。结果热网络模型预计的温度结果和实测结果较为吻合,95%置信度下实测数据与预计的日高温极值误差均值为0.3℃。结论该方法对舱内温度的预计结果较好,可用以确定空空导弹的环境适应性要求。     

环境气象因素监测分析在太阳能热发电站选址快速评估中的应用

目的对凉山州某地太阳能热发电站拟选场址的太阳能资源进行评估。方法利用环境气象因素监测设备监测太阳直接辐射、总辐射和温湿度等环境气象因素,采用经验公式估算凉山州某地全年太阳直接辐射和总辐射量,并利用实测值进行验证。结果某地在秋冬之交,直接辐射强度的平均值为5.7k W·h/(m~2·d),总辐射强度的平均值为5.1 k W·h/(m~2·d)。结论某地为太阳能资源很丰富地区,全年太阳直接辐射量大于5000 MJ/m~2,全年太阳总辐射量大于6000 MJ/m~2,2月、3月、4月和5月为太阳能热发电最佳经济运行的月份。在秋冬之交,有利因素为70%以上的天数直接辐射强度都大于经济性运行的直接辐射强度指标,利于太阳能热发电,是潜在的太阳能热发电站候选地区;不利因素为多云天气和阴天占总天数的百分比接近50%,会极大地影响太阳能热发电的发电量和发电效率。