珠江三角洲地区工业排放变化对SO2和NOx及其二次污染物浓度的影响

在2000年珠江三角洲工业排放清单基础上,利用2003年工业能源消耗量,结合文献和实测排放系数,建立了珠江三角洲2003年工业排放清单. 比较2个工业排放清单发现,2003年珠江三角洲SO₂,NO_x的工业总排放量比2000年分别增加60%与50%;排放增加主要在东莞、佛山、广州和珠海. 利用在线大气化学模式(WRF-Chem)分别对2个工业排放清单进行数值模拟,结果表明: ρ(SO₂),ρ(NO_x)变化趋势与污染源排放的变化有较好的对应关系,ρ(SO₂)在东莞、广州和佛山增加最多,最大增值分别为180,150和150 μg/m3;ρ(NO_x)增加最多的地区也在东莞、广州和佛山,最大增值分别为60,30 和30 μg/m3. SO₄2－与NO₃－和一次污染物的高值中心不对应且变化趋势有差异,表明二次污染物的分布不仅受排放影响,同时也受污染物输送与转化的影响.      

基于卫星数据研究兰州市NO2时空分布特征以及冬季NOx排放通量

搭载在EOS AURA卫星上的OMI探测器由于其较高时空分辨率在大气痕量气体(O3,NO2,SO2)探测中得到广泛应用.利用2010~2012年OMI NO2柱浓度数据产品重构了兰州市以及周边地区NO2柱浓度分布,分析了其时空变化特征,并利用西南风场下NO2空间分布特征采用拟合方法研究了NOx冬季排放通量以及寿命.研究表明,NO2柱浓度空间分布呈现以兰州市为中心,浓度向四周扩散的特征;兰州市NO2柱浓度的年变化特征为12月达到最大浓度,8月达到最小浓度;2010~2012年NO2寿命分别为10.6,9.9,9.1h,NOx冬季排放通量分别为175.3, 183.7,179.9mol/s.其排放通量与兰州环境公报提供的氮氧化物排放通量数量级之间具有较好的一致性,说明利用卫星数据估算兰州的NOx通量方法的有效性.     

NiB2O4 (B = Mn or Co) catalysts for NH3-SCR of NOx at low-temperature in microwave field

● Microwave-assisted catalytic NH₃-SCR reaction over spinel oxides is carried out. ● SCR reaction temperature is tremendously lowered in microwave field. ● NO conversion of NiMn₂O₄ is highly up to 90.6% at 70°C under microwave heating. Microwave-assisted selective catalytic reduction of nitrogen oxides (NO_x) was investigated over Ni-based metal oxides. The NiMn₂O₄ and NiCo₂O₄ catalysts were synthesized by the co-precipitation method and their activities were evaluated as potential candidate catalysts for low-temperature NH₃-SCR in a microwave field. The physicochemical properties and structures of the catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), N₂-physisorption, NO adsorption-desorption in the microwave field, H₂-temperature programmed reduction (H₂-TPR) and NH₃-temperature programmed desorption (NH₃-TPD). The results verified that microwave radiation reduced the reaction temperature required for NH₃-SCR compared to conventional heating, which needed less energy. For the NiMn₂O₄ catalyst, the catalytic efficiency exceeded 90% at 70 °C and reached 96.8% at 110 °C in the microwave field. Meanwhile, the NiMn₂O₄ also exhibited excellent low-temperature NH₃-SCR reaction performance under conventional heating conditions, which is due to the high BET specific surface area, more suitable redox property, good NO adsorption-desorption in the microwave field and rich acidic sites.     

燃烧过程氮氧化物系统中反应和传递模型研究进展

氮氧化物是空气中主要污染物之一,随着计算燃烧学迅速发展,氮氧化物(NOx)生成反应和传递过程的模拟在燃烧反应器设计工作中所起的作用越来越重要,如何建立合理而经济的预测模型,是其中的关键问题之一。根据国内外的研究现状,本文对燃烧过程氮氧化物系统中的反应和传递模型研究进展进行了评述,讨论了各个模型的优点和不足,并提出了NOx预测模型今后的发展方向。     

华北洁净地区微量气体变化特征的初步研究

2005-05-22-2005-12-31,在中国科学院大气本底观测网兴隆站对微量气体成分进行连续测量,获得了O₃,NOx(NO,NO₂),CO₂和SO₂等气体组分的变化特征和变化规律,并得到了它们的浓度水平.初步分析表明,ψ(O₃)在6,9月出现高值,12月出现最低值;ψ(NOx)的最低值出现在8月,8-11月缓慢增长,NO在NOx中所占比例非常小;ψ(SO₂)的最低值出现在7月,之后逐渐增加;ψ(CO₂)的最低值出现在8月.观测资料表明,兴隆站空气质量最好的时间为7-8月.并对它们之间的相互作用及与辐射的关系进行了研究.      

Unraveling SO2-tolerant mechanism over Fe2（SO4）3/TiO2 catalysts for NOx reduction

Developing low-temperature SO₂-tolerant catalysts for the selective catalytic reduction of NO_x is still a challenging task. The sulfation of active metal oxides and deposition of ammonium bisulfate deactivate catalysts, due to the difficult decomposition of the as-formed sulfate species at low temperatures（<300 °C）. In recent years, metal sulfate catalysts have attracted increasing attention owing to their good catalytic activity and strong SO₂ tolerance at hi...     

火电厂氮氧化物排放量动态更新方法研究

有效控制氮氧化物是我国“十二五”环保重点工作之一,如何实现氮氧化物减排监管和核查核算显得十分重要,但是我国尚未建立科学合理的行业氮氧化物排放量核算核查方法。以火电行业为研究对象,首次系统提出火电行业氮氧化物排放量的动态更新方法。提出3种不同的污染源排放动态更新方法：源活动强度动态更新法、污染源增减动态更新法、综合排放因子动态更新法,详细分析了方法原理、计算公式和使用范围,并在2008年我国火电氮氧化物排放量基础上,分别对2009年火电氮氧化物排放量进行了动态更新核算     

基于杂多酸修饰电极NOx传感器的制备与应用

氮氧化物NOx是一类重要的环境污染物,对其进行监测十分必要。通过电化学方法制备了金钼杂多酸薄膜修饰电极,研究了该电极的电化学行为及其对酸性水溶液中NOx的电催化作用。结果表明,在5．0×10^-4-1．6×10^-2moL／L范围内NOx浓度与其氧化峰电流之间呈线性关系,检出限可达8．0×10^-5mol／L,满足环境水样中NOx的检测要求。     

Regional NOx emission inversion through a four-dimensional variational approach using SCIAMACHY tropospheric NO2 column observations

In this paper, the NOx emission scaling factors applied over the 2001 National Emissions Inventory (NEI) are estimated through a four-dimensional variational (4D-Var) approach using SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY) tropospheric NO₂ columns measured during summer 2004. In the “top-down” approach, two-month average NO₂ columns are assimilated into a regional chemical transport model (CTM), STEM, using different assimilation setups. In a basic setup, NOx emissions are adjusted by assimilating the NO₂ columns. A more general setup of emission inversion allows the initial O₃ concentrations be adjusted along with the NOx emissions. A final case is set up to assimilate both the NO₂ columns and O₃ measurement from various platforms while allowing adjustments of both the NOx emissions and the initial O₃ concentrations. It is found that the addition of O₃ measurements did not improve the NOx emission inversion. With the NOx emission at surface and upper levels being adjusted separately, results from four cases show that the elevated NOx emission reduction ranges from 8.9% to 11.4%, and the surface NOx emission reduction is up to 6.6%. All the cases show NOx emission reduction in Ohio valley and Washington, District of Columbia areas.     

火电厂脱NOx用SCR催化剂种类及工程应用

介绍了SCR法脱除氮氧化物的催化剂种类,着重介绍了商业用钛基脱硝催化剂和现阶段国内脱硝催化剂的应用情况,讨论了导致催化剂中毒的各种原因,阐述了燃煤电厂应用SCR技术中对催化剂的要求。