Catalytic Combustion of Model Carbon Particles (CPs) over Pt/β-SiC Catalyst

Platinum catalyst supported on a medium surface area -SiC was successfully used for the catalytic combustion of model carbon particles and compared to a catalyst supported on a low surface area -SiC. The -SiC-based catalyst showed no deactivation as a function of cycling tests while a strong deactivation was observed on the -SiC-based catalyst. This deactivation was attributed to the progressive encapsulation of the platinum particles by a layer of silica which built up during the combustion cycle. These results render possible the use of Pt/-SiC catalyst as a diesel carbon particle catalytic filter with continuous regeneration.     

Diffusion of ellipsoidal granular particles in shear flow

The diffusion of nonspherical particles has not been well understood due to the complexity of their contact mechanics and self-organization of their orientations. We perform discrete element method simulations of monodisperse ellipsoids in a shear flow with Lees-Edwards boundary conditions to quantify the relation between the diffusion coefficient and the flow parameters. The results indicate that the particle aspect ratio strongly affects the diffusion coefficient by influencing the particle orientation and alignment. We develop a scaling law for the diffusion coefficient perpendicular to the flow direction, D_yy, which combines the influences of the shear rate , the solids fraction f, the effective particle diameter d_eff and the particle aspect ratio Z. We show that , where k_d is a dimensionless pre-factor, and a fit is obtained for the functional form of χ(f, Z). This scaling law will be useful in developing continuum transport models for applications.     

办公建筑中空调形式对室内外PM2.5浓度相关性的影响

室外PM2.5可通过新风及围护结构缝隙渗透至室内,室外PM2.5较高时尤为明显,结果导致室内空气中的PM2.5浓度上升。为了研究空调形式对室内外PM2.5浓度相关性的影响,在2015年夏季对重庆某办公建筑中采用不同空调形式的室内外PM2.5浓度进行了实测。实测结果发现：集中式空调、分体式空调和非空调房间室内外PM2.5浓度比变化范围分别为0.59～0.76、0.47～0.76、0.71～0.91。室内外PM2.5浓度相关性系数的排序为：集中式空调环境（0.94）> 非空调环境（0.92）> 分体式空调环境（0.77）,研究结果表明,办公建筑的空调形式,对室内外PM2.5浓度的相关性有影响。     

A review of the health effects and exposure-responsible relationship of diesel particulate matter for underground mines

The increasing use of diesel-powered equipment in confined spaces(underground mines) has the potential to over expose underground miners under the threat of diesel particulate matter(DPM). Miners in underground mines can be exposed to DPM concentrations far more than works in other industries. A great number of animal and epidemiological studies have shown that both short-term and long-term DPM exposure have adverse health effect. Based on reviews of related studies, especially some recent evidence, this paper investigated the long and short-term health effects based on animal studies and epidemiological studies. The exposure-response relationship studies were also explored and compared to the current DPM regulation or standards in some countries. This paper found that the DPM health effect studies specifically for miners are not sufficient to draw solid conclusions, and a recommendation limit of DPM concentration can be put in place for better protection of miners from DPM health risk. Current animal studies lack the use of species that have similar lung functions as human for understanding the cancer mode of action in human. And finally, the DPM health hazard will continue to be a challenging topic before the mode of action and reliable exposure-response relationship are established.     

PH F-101催化剂在柴油加氢装置的工业应用

介绍了PHF-101柴油加氢精制催化剂在中国石油天然气股份有限公司兰州石化分公司现有3.0Mt/a柴油加氢装置工业应用情况。装置运行情况及标定结果表明,PHF-101催化剂加氢性能优良,运转稳定性良好,完全满足企业长周期稳定生产国Ⅳ柴油并兼顾国Ⅴ质量生产能力的需求。     

藻细胞内外有机物氯消毒后典型消毒副产物的生成潜能

为探究藻细胞内外有机物氯化后典型消毒副产物的生成潜能,选取小球藻为研究对象,采用加氯消毒法研究了在不同生长时期及不同氯投加量下典型含碳类消毒副产物(THMs)和含氮类卤代消毒副产物(TCNM)的生成规律,并对二者的生成势进行了对比.结果表明:细胞外有机物(EOM)和细胞内有机物(IOM)提取液的总有机碳(TOC)和有机氮(DON)较高,而芳香结构和不饱和双键的有机质质量浓度很低;从对数生长期到衰亡期,EOM经氯化后TCNM的生成量逐渐增加,IOM的TCNM生成量则呈现先增加后降低的趋势;THMs的生成规律与TCNM相似,但其生成量明显高于TCNM.增加氯投量,EOM的TCNM生成量逐渐升高,IOM的TCNM生成量则先升高后下降;在氯投量为30 mg/L时,IOM的TCNM生成量最高;稳定生长期小球藻细胞的EOM和IOM在氯投量由20 mg/L升高到30 mg/L时,THMs的生成量稳定增加,当氯投量超过30 mg/L时,THMs的生成势显著升高,且三氯甲烷为THMs的主导物种.     

电控柴油机分缸均衡控制算法及试验

柴油机各个气缸的进气量、喷油量、燃烧等存在差异,导致气缸间存在做功差异,直接影响柴油机转速的平稳性以及排放性能等。针对位置式电控柴油机,采用PI闭环控制,通过瞬时转速信号识别并计算各缸的工作差异,利用分缸均衡控制算法对油量进行补偿修正。试验结果显示低转速稳态工况转速波动由7 r/min降至3 r/min,各缸工作不均匀度由±5 r/min降至±2 r/min,在瞬态过程和高转速3 400 r/min时该算法仍然适用有效。     

基于STAR-CCM+的防爆柴油机水冷式排气管数值模拟分析

防爆柴油机水冷式排气管是其排气装置的重要组成部分,是高温废气在排气系统各部件间流动时温度达标的重要保证。文章利用STAR-CCM+软件对两种水冷式排气管进行了网格划分和物理模型设定,通过数值模拟分析,结果表明:新结构的水冷式排气管温度分布均匀,没有出现过热区域,并且换热性能更好。     

腐殖活性污泥生化特征及处理效能

为探讨腐殖活性污泥的生物化学特征及其作用机理,对腐殖生物填料进行扫描电镜和能谱(SEM-EDAX)测定,表明填料中主要组成元素为C、O、Si,同时含有少量Al、S、Fe. 腐殖活性污泥与普通活性污泥中若干特征菌群的对比分析表明,腐殖活性污泥中的一般细菌总量、硝酸菌、亚硝酸菌、脱氮菌及放线菌含量明显高于普通活性污泥;腐殖活性污泥中有机质的质量分数比普通活性污泥低,但腐殖酸及富里酸和胡敏酸质量分数明显高于普通活性污泥;腐殖活性污泥法运行的SBR反应器对CODCr、TP和TN的去除效果优于普通SBR反应器,分别高出4％、14％和10％．     

大气颗粒物源解析监测中的质量控制

为确保石家庄市大气颗粒物源解析研究数据的准确性和精密性,首先结合城市自然环境、能源结构、大气环境质量现状等进行合理布点采样,同时在大气颗粒物样品采集、滤膜称量、化学组分分析等监测过程中实施了空白分析、实验室平行样分析、标准曲线绘制与核查、加标回收、有证标准物质核查等一系列质量保证措施,通过对这些质量保证措施实施情况的阐述与质量控制数据的统计、计算与分析,证明了该大气颗粒物源解析监测工作从样品采集及其称量到化学组分分析等全过程是真实有效的,表明了石家庄市大气颗粒物源解析监测数据的准确性和监测工作的可靠性.