Numerical evaluation of the effectiveness of NO2 and N2O5 generation during the NO ozonation process

Wet scrubbing combined with ozone oxidation has become a promising technology for simultaneous removal of SO₂ and NO_x in exhaust gas. In this paper, a new 20-species, 76-step detailed kinetic mechanism was proposed between O₃ and NO_x. The concentration of N₂O₅ was measured using an in-situ IR spectrometer. The numerical evaluation results kept good pace with both the public experiment results and our experiment results. Key reaction parameters for the generation of NO₂ and N₂O₅ during the NO ozonation process were investigated by a numerical simulation method. The effect of temperature on producing NO₂ was found to be negligible. To produce NO₂, the optimal residence time was 1.25 sec and the molar ratio of O₃/NO about 1. For the generation of N₂O₅, the residence time should be about 8 sec while the temperature of the exhaust gas should be strictly controlled and the molar ratio of O₃/NO about 1.75. This study provided detailed investigations on the reaction parameters of ozonation of NO_x by a numerical simulation method, and the results obtained should be helpful for the design and optimization of ozone oxidation combined with the wet flue gas desulfurization methods (WFGD) method for the removal of NO_x.     

基于功能安全标准的安全仪表系统可靠性评估软件

介绍了以功能安全国际标准IEC61508和IEC61511工程应用要求为依据,集安全仪表系统的安全仪表功能安全完整性等级(SIL)分配、安全要求规范(SRS)制定、SIL验证、可靠性数据管理等多功能为一体的安全仪表系统可靠性专用评估软件。     

传感技术用于甲醛测定的研究

甲醛是一种重要的工业原料,在化工、食品、建材等方面有着广泛的应用。由于甲醛毒性大,且被怀疑具有致癌作用,目前已被认为是工厂区和室内空气中最重要的污染物之一。随着人们对空气污染的日益关注,对甲醛的准确及时检测显得更加重要。基于传感器技术而研制出的甲醛测定仪,让我们看到传感技术运用于甲醛测定领域的发展前景。本文就测定甲醛的传感器技术如电化学传感器、光化学传感器、金属氧化物传感器、电子鼻以及声表面波式传感器的一些重要应用进行了阐述。     

芳香烃清洁硝化催化剂

综述了国内外有关芳香烃硝化过程中替代硫酸的催化剂的研究进展;介绍了沸石类催化剂、粘土类催化剂、离子交换树脂催化剂、固载化液体酸催化剂、金属氧化物及金属盐催化剂、杂多酸催化剂以及固体超强酸催化剂的合成及催化效率与优缺点.     

低pH值对大型溞（Daphnia magna Straus）存活、生长和生殖的影响

在静置换水条件下,研究了低pH值对大型存活、生长和生殖的影响。结果表明,在25±1℃下,急性试验低pH值对大型的24h和48hLL50值及其95％可信限分别为pH值4.66±0.19和4.94±0.20。慢性试验进行了14天,对存活和生长,pH值1.75有影响,pH值5.0没有影响;对生殖,pH值5.0有影响,pH值5.5没有影响。显示出低pH值对大型的毒性阈限在pH值5.00－5.50之间。     

釜溪河自贡城区段季节性低氧成因研究

釜溪河为沱江一级支流,在自贡城区段设有国考碳研所断面。收集碳研所断面近10年来水质自动站数据,分析溶解氧(DO)变化特征,采样调查釜溪河自贡城区段水质及河道底泥污染状况,采用相关性分析、数值模拟等,研究分析釜溪河自贡城区段溶解氧分布特征及碳研所断面季节性低氧成因。研究结果表明,碳研所断面的溶解氧质量浓度变化特征呈现春末夏初最低,白天高晚上低的特征。釜溪河碳研所断面河水耗氧类污染物质量浓度较沱江流域内其他断面高,耗氧强度较大,溶解氧质量浓度较沱江流域其他断面偏低;其次,研究河段中釜溪河污水厂以下河段受污水厂低氧水排入和金子凼堰底层低氧水下泄影响,其溶解氧水平整体较污水厂以上河段低;最后,河段底泥有机质含量较高,春夏季气温升高将导致微生物分解活性增强大量消耗溶解氧,同时,闸坝和外来水体排入的水文扰动造成污水厂以下河段水温梯度弱,表层溶解氧易受底层低氧水影响,促使断面形成季节性低氧现象。溶解氧预测模型结果也进一步证实了温度变化和垂向温度梯度弱是碳研所断面溶解氧质量浓度季节性偏低的主要因素。     

辽宁省港口邻近区域海运废气排放测算

为准确测算沿海地区船舶废气排放量,基于试验数据确定了NO_x、CO、HC和CO₂排放因子;结合文献资料和海事局进出港船舶签证数据,采用基于船舶活动过程的方法测算了2014年辽宁省港口邻近区域〔距港口减速区外边界25 n mile(1 n mile=1 852 m)以外的边界线与港口陆地岸线所围成的区域〕海运废气排放清单. 结果表明:2014年辽宁省港口邻近区域海运NO_x、CO、HC、CO₂、SO₂和PM(颗粒物)的排放量分别为11 827.1、971.4、399.6、1 097 426.5、11 654.1和959.2 t;散货船、集装箱船和油船3种主要类型船舶的NO_x、CO、HC、CO₂、SO₂和PM的分担率之和分别为74.7%、77.8%、70.8%、68.0%、70.9%和70.6%;主机NO_x、CO、HC、CO₂、SO₂和PM的分担率最大,分别为63.7%、63.0%、46.0%、40.4%、46.4%和45.3%;停泊工况下的NO_x、CO、HC、CO₂、SO₂和PM排放量分别为3 318.3、281.7、168.3、520 194.9、4 894.0和411.5 t. 船舶降速运行、减少停港时间、燃用低硫油和向船舶供应岸电等措施能降低港口邻近区域海运废气排放. 基础数据缺乏或数据代表性不足给废气排放清单带来了一定的不确定性.      

东北玉米热量指数预测方法研究(Ⅲ)——GM(1,1)预测方法

GM(1,1)是开展时间序列环境要素变化趋势预测的有效方法之一。通过对东北地区玉米热量指数的分析,建立了热量指数时间变化趋势的GM(1,1)预测模型,各模型的平均预测精度虽低于逐步回归统计模型,但也都达91%以上,可以应用该模型的预测结果指导农业生产。     

New advances in plant growth-promoting rhizobacteria for bioremediation

Plant growth-promoting rhizobacteria (PGPR) are bacteria capable of promoting plant growth by colonizing the plant root. For a long period PGPR were mainly used for assisting plants to uptake nutrients from the environment or preventing plant diseases. Phytoremediation is a new and promising approach to remove contaminants in the environment. But using plants alone for remediation confronts many limitations. Recently, the application of PGPR has been extended to remediate contaminated soils in association with plants. Of all the present contaminants, the profound impacts of organic and heavy metal pollutants have attracted world wide attention. Here we review the progress of PGPR for remediation of soils contaminated with these two sources.     

Ecological selection of bacterial taxa with larger genome sizes in response to polycyclic aromatic hydrocarbons stress

Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous priority pollutants that cause great damage to the natural environment and health. Average genome size in a community is critical for shedding light on microbiome’s functional response to pollution stress within an environment. Here, microcosms under different concentrations were performed to evaluate the selection of PAHs stress on the average genome size in a community. We found the distinct communities of significantly larger genome size w...