粉煤灰静电脱炭技术研究

本文介绍粉煤灰静电脱炭资源化利用技术的试验研究.利用YNDF-I型立式电场粉煤灰脱炭装置进行优化试验,提出电压、极板间距、摩擦分散器材料、粉尘浓度及气体流量等运行工艺特性参数与静电脱炭率的相关关系.试验结果表明,该立式电场脱炭装置在最优工艺参数条件下运行时,可使粉煤灰脱炭后的精灰含炭量降低到1.20%,脱炭率达86.74%,能够直接代替水泥用作建筑材料或修筑公路路面,具有较高的经济效益、社会效益和环境效益,为粉煤灰资源化利用提供了一种新的途径.     

液相络合-铁粉还原-酸吸收回收法脱除烟气中NO

提出了Fe2+螯合剂络合-铁粉还原-酸吸收回收法脱除烟气中NO的新工艺,重点研究了模拟烟气中O₂含量对NO络合量的影响,以及铁粉用量、铁粉粒径和搅拌速度对脱氮效率的影响,确定了最佳的铁粉脱氮工艺条件,并对铁粉和铁屑的脱氮效果进行了比较.结果表明:烟气中φ(O₂)从0增加到4.2%,NO络合量下降90.2%;脱氮效率随铁粉用量和反应器搅拌速度的增加而增加,随铁粉粒径的增加而降低;最佳工艺参数为,铁粉用量0.8 g,铁粉粒径≥200目(≤0.077 mm),搅拌速度900 r/min,在该条件下,对φ(O₂)为5%的模拟烟气在搅拌反应器中可取得90%以上的脱氮效率;用铁粉在1台搅拌反应器中取得的脱氮效率和用铁屑在2个鼓泡反应器串联时所取得的效率相当.      

Metal pollution status of Tajan River – Northern Iran

The monitoring of surface water quality of rivers is crucial to protect aquatic life and receiving water bodies of economic importance. The aim of the current study was to examine selected physicochemical parameters of River Tajan due to its ecological importance in Iran. Water samples from nine points covering the entire Tajan River and Caspian Sea estuary were collected and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), carbonates, chlorides and selected heavy metals including zinc, cadmium, lead and chromium. The pH and levels of EC, TDS, chlorides, carbonates and all metals were within the USEPA reference guidelines for surface water quality standards. Although these water quality parameters are considered safe, continuous monitoring and assessment is recommended in order to protect the coastal receiving waters of Caspian Sea which serves as a tourist attraction in northern Iran.     

Assessment of seasonal variations of carbon dioxide concentration in Iran using GOSAT data

Global warming and climate change have been identified as the most important challenges of the 21st century. Greenhouse Gases Observation Satellite (GOSAT) measures the concentrations of carbon dioxide (CO ₂) and methane (CH ₄) in the atmosphere column from the earth's surface to the upper atmosphere. In this research, GOSAT Thermal And Near Infrared Sensor for Carbon Observation – Fourier Transform Spectrometer (TANSO‐FTS) level 2 data and meteorological parameters were used in the assessment of changes in CO ₂ concentration (XCO ₂) from 2009 to 2015. We investigated the relationship between XCO ₂ and meteorological parameters (temperature and precipitation) obtained from weather stations and the Normalized Difference Vegetation Index (NDVI) in the year 2013 in Iran. The results reveal a steady increase in the mean atmospheric CO ₂ concentration, from 384.89 to 400.39 ppm. It was observed that the XCO ₂ varied significantly depending on the month, with the highest concentration of CO ₂ in April/May and the lowest concentration in August/September. The correlation between XCO ₂ and average monthly air temperature is negative, which means that a reduction in XCO ₂ with an increase in temperature is dependent on photosynthetic activities in the growing seasons. The highest and lowest correlation coefficient between the NDVI and XCO ₂ was obtained in the spring and in the fall, respectively. These findings are useful for recognizing factors that affect CO ₂ concentration in different seasons in arid and semi‐arid regions, and as an initial step toward sustainable management.     

汽车排放污染物浓度的预测

为了预测汽车排放污染物的浓度,应用简化的高斯烟团模式得到静风条件下的线源扩散预测模式。并结合高斯烟流扩散模式,建立了预测汽车污染物在任意风向下和年平均浓度的预测模式,考虑车道上存在车辆行驶的强烈机械扰动湍流和把繁忙的公路视为线源两个因素,提出了计算初始扩散参数的方法。然后,运用Turner和Pasquill扩散参数,建立了线源扩散参数的确定方法。该模式应用于预测高速公路沿途汽车污染物的浓度表明,计算值与监测值吻合较好,可用于我国公路环境影响的评价。     

汽车尾气的初期扩散与扩散参数

通过风洞模拟实验,分析研究汽车尾流区的流场特性,确定了汽车机械扰动产生的尾气初期扩散范围,提出了一种考虑初期扩散影响的确定近距离扩散参数的简易方法。现场示踪实验和实测资料的验证表明,用该方法确定尾气扩散参数是可靠的。     

溶剂萃取法提取电镀污泥氨浸出渣中的金属资源

研究硫酸浸出Ｐ５０７－煤油－硫酸体系萃取分离铁,钠皂－Ｐ２０４－煤油－硫酸体系共萃铬、铝、反萃取分离铬、铝工艺回收电镀污染氨浸渣中的金属。通过优化实验,确定了全流程的最佳工艺参数。结果表明,铁铬渣中的金属铬、铝和铁均可以高纯度盐类形式回收,可作为化学试剂使用,回收率达９５％以上。     

Perfluorocarbon background concentrations in Europe

Five studies of the background level of several perfluorocarbon compounds in Europe are here presented together with measurements from the European Tracer Experiment (ETEX). The tracers used during the two ETEX tracer releases were the perfluorocarbons (PFCs); perfluoromethylcyclohexane (C₇F₁₄, PMCH) and perfluoromethylcyclopentane (C₆F₁₂, PMCP). Their background concentrations were detected by using both passive and active sampling techniques, to define the spatial and temporal variation of the PFCs over Europe. Also the background variations of four isomers of the PFC compound perfluorodimethylcyclohexane (C₈F₁₆, PDCH) were studied. The results were compared to other PFC tracer studies in the U.S.A. and Europe. The mean and median values of the measured PFCs were found to vary slightly and randomly in space and time. They were found to be higher and to have a larger standard deviation than the measurements from the American studies. The background concentrations were still found to be low and stable enough for PFCs to be highly suitable for use in tracer studies. The following concentrations were found: PMCP; 4.6±0.3 fl ℓ^-1, PMCH: 4.6±0.8 fl ℓ^-1, ocPDCH: 0.96±0.33 fl ℓ^-1, mtPDCH: 9.3±0.8 fl ℓ^-1, mcPDCH: 8.8±0.8 fl ℓ^-1, ptPDCH: 6.1±0.8 fl ℓ^-1. A study of the correlation between the measured PFC compounds showed a significant correlation between most of the compounds, which indicate that there are no major PFC sources in Europe.     

Evaluation of the effect of meteorological data resolution on Lagrangian particle dispersion simulations using the ETEX experiment

This paper presents results from a series of numerical experiments designed to evaluate operational long-range dispersion model simulations, and to investigate the effect of different temporal and spatial resolution of meteorological data from numerical weather prediction models on these simulations. Results of Lagrangian particle dispersion simulations of the first tracer release of the European Tracer Experiment (ETEX) are presented and compared with measured tracer concentrations. The use of analyzed data of higher resolution from the European Center for Medium-Range Weather Forecasts (ECMWF) model produced significantly better agreement between the concentrations predicted with the dispersion model and the ETEX measurements than the use of lower resolution Navy Operational Global Atmospheric Prediction System (NOGAPS) forecast data. Numerical experiments were performed in which the ECMWF model data with lower vertical resolution (4 instead of 7 levels below 500 mb), lower temporal resolution (12 h instead of 6 h intervals), and lower horizontal resolution (2.5° instead of 0.5°) were used. Degrading the horizontal or temporal resolution of the ECMWF data resulted in decreased accuracy of the dispersion simulations. These results indicate that flow features resolved by the numerical weather prediction model data at approximately 45 km horizontal grid spacing and 6 h time intervals, but not resolved at 225 km spacing and 12 h intervals, made an important contribution to the long-range dispersion.     

Establishment the relationship between water quality parameter and micro plastic concentration for Adyar and Cooum estuary

Increasing micro plastic concentration in the marine environment is a severe threat to the marine ecosystem and indirectly to human society depending on the marine environment. Also, the surface and subsurface water quality parameters are the indicators of the usability of the water sources for human activities. The primary source of micro plastic is the water river systems from land to sea. This study establishes a correlation between water quality parameters and micro plastic concentration to find the most suitable quality parameter for finding the micro plastic concentration in urban coastal estuaries of Chennai coast, Tamil Nadu, India. Twenty samples from Adyar and Cooum estuaries were collected, with ten each on August 2019 and August 2020. They are tested for temperature pH, EC, Turbidity, TDS, DO, BOD, COD, Salinity and micro plastic concentrations. Correlation tests such as Pearson's and Spearman's are performed based on the initial Normality and Homogeneity test. The results show that all the parameters are significantly not correlated with the Micro plastic Concentration, and Micro plastic Concentration is considered an independent factor.