10000 m~3/h制氧机产能下降原因分析与处理措施

分析了10000 m3/h制氧机产能和产况下降的原因,并提出相应的处理措施,对制氧机的安全稳定生产起到了一定的实际指导作用。     

加强电力技术监督管理 提高生产安全水平

在电力生产过程中,各个环节联系紧密,任何一环出了问题,将产生由点及面,甚至到片的故障,将给企业、工农业生产带来相当严重的影响。所以,加强对电力技术监督管理,加强对电力安全生产环节的有效监督,显得尤其重要。文中从安全生产工作现状、电力技术监督管理意义及措施等方面展开了分析。     

测量水平油水层状流相含率的平行线电容传感器

提出了一种用于水平油水层状流相含率测量的平行线电容传感器。采用有限元分析方法(FEM)考察了传感器灵敏场分布,分析了传感器几何参数对灵敏场影响;构建了传感器层状流下的有限元模型,计算得到了水平油水层状流条件下的传感器静态响应特性;在设计传感器测量系统基础上进行了传感器水平油水层状流相含率测量,结果表明,平行线电容传感器输出响应与有限元模型计算结果较好吻合,且对相含率具有较高的测量线性度及灵敏度。     

Ultrasonic spray pyrolysis synthesis of Ag/TiO2 nanocomposite photocatalysts for simultaneous H2 production and CO2 reduction

Simultaneous photocatalytic hydrogen production and CO₂ reduction (to form CO and CH₄) from water using methanol as a hole scavenger were investigated using silver-modified TiO₂ (Ag/TiO₂) nanocomposite catalysts. A simple ultrasonic spray pyrolysis (SP) method was used to prepare mesoporous Ag/TiO₂ composite particles using TiO₂ (P25) and AgNO₃ as the precursors. The material properties and photocatalytic activities were compared with those prepared by a conventional wet-impregnation (WI) method. It was found that the samples prepared by the SP method had a larger specific surface area and a better dispersion of Ag nanoparticles on TiO₂ than those prepared by the WI method, and as a result, the SP samples showed much higher photocatalytic activities toward H₂ production and CO₂ reduction. The optimal Ag concentration on TiO₂ was found to be 2 wt%. The H₂ production rate of the 2% Ag/TiO₂–SP sample exhibited a six-fold enhancement compared with the 2% Ag/TiO₂–WI sample and a sixty-fold enhancement compared with bare TiO₂. The molar ratio of H₂ and CO in the final products can be tuned in the range from 2 to 10 by varying the reaction gas composition, suggesting a viable way of producing syngas (a mixture of H₂ and CO) from CO₂ and water using the prepared Ag/TiO₂ catalysts with energy input from the sun.     

Lipid production in mixotrophic cultivation of Chlorella vulgaris in a mixture of primary and secondary municipal wastewater

Microalgae's biomass productivity and oil content depend heavily on the method of its cultivation. In this study, nutrient removal from municipal wastewater by Chlorella vulgaris in batch culture was investigated. Carbon dioxide was supplied from sodium hydrogen carbonate. Effect of parameters including light intensity, sodium hydrogen carbonate concentration, and daily illumination time on the productivity of biomass and lipid was investigated. Lipid and biomass production of C. vulgaris increased at higher concentration of sodium hydrogen carbonate concentration and higher light intensity until a certain value and then decreased, but longer daily illumination time, increased both biomass and lipid productivity. Cultivation of C. vulgairs in mixotrophic mode was also studied in a mixture of primary and secondary wastewater with different ratios (25, 50 and 75 volume percent of the primary wastewater). It was observed that using 25% of the primary wastewater results in 100% COD removal, 100% ammonium removal and 82% nitrate elimination. Biomass productivity and lipid productivity of C. vulgaris in a mixture of primary (25%) and secondary wastewater were 138.76 mg/L/d and 45.49 mg/L/d, respectively.     

Cultivating the marine microalga Nannochloropsis salina under various nitrogen sources: Effect on biovolume yields,lipid content and composition,and invasive organisms

Algae can be a viable source for biofuel production, but the source of nitrogen used to cultivate could affect algae yields. Here, we observe how various nitrogen treatments can impact the growth and biovolume of microalga Nannochloropsis salina as well as invasion of undesired organisms. Invading organisms increase the likelihood of crashes of the desired microalgae culture. Experiments were conducted over 28 days in open aquaria in a greenhouse. We used five different nitrogen treatments; ammonium chloride (NH₄Cl), ammonium hydroxide (NH₄OH), sodium nitrate (NaNO₃), urea (CH₄N₂O), and a mixture of all these sources. Highest values for Maximum Sustainable Yield (MSY), a measure of potential harvest rate based on population productivity, were observed in the urea treatment, but cell size was smaller compared to other treatments. Sodium nitrate and the mixture of nitrogen sources also had high MSY values but larger cell sizes, making them the treatments with highest total biovolume. The highest percentages of lipid by weight, but also highest densities of invading organisms were observed in the mixed treatment. Our results suggest that tradeoffs between biovolume and lipid yields as well as culture success can ultimately decide what nitrogen sources to use.     

Relationships between observed and perceived deviations from normative work procedures

Deviations from anticipated courses of events are often associated with accidents, while the effects of deviations that decrease productivity but do not obviously lead to human injury are less clear. A systemic approach to production and safety is introduced, and it is proposed that production deviations have effects that may lead to safety violations and personal injury. In addition, the relationship between observed and perceived production deviations from 12 senior (60–79 years old) males' routine work using three firewood processing machines is analysed. For simple machine work, perceived deviations were positively related to observed deviations per work cycle and inversely correlated to the perception of work efficiency. For more complex machine work it was more difficult to match observers' and operators' perceptions of deviations. Despite challenges in the production deviation concept, this approach offers a holistic understanding of the performance of human–machine-environment systems and complements assessments of deviations from safe working practice.     

浅论大同市能源利用现状及策略

分析了大同市能源资源利用条件,对大同市能源利用面临的机遇和挑战做了深入的剖析,针对现状存在的问题,提出了大同市能源利用发展策略。     

An efficient ZnS-UV photocatalysts generated in situ from ZnS(en)0.5 hybrid during the H2 production in methanol–water solution

Highly active ZnS-UV was obtained in situ from ZnS(en)_0.5 hybrid during the hydrogen formation using a methanol–water solution under UV irradiation. X-ray diffraction patterns and UV spectroscopy for both ZnS-UV and ZnS-400 obtained from the calcination of the ZnS(en)_0.5 hybrid showed similar structural and photophysical properties; however, the efficiency of the ZnS-UV semiconductor was 7 times higher (4825 μmol h⁻¹ g⁻¹) compared to the ZnS-400. The highest H₂ production was obtained using a UV lamp of very low intensity (2.2 mW cm⁻¹) and it is attributed to a quantum size effect caused by the slow elimination of ethylenediamine (en) in the structural ZnS layer during the UV irradiation.