上海市区道路地面氮氧化物污染现场调查

为了解城市道路地面NOx污染的状况和特征，对上海典型道路路边NOx污染进行现场实测。结果表明：在交通繁忙的路段，路边NOx污染严重。调查发现：路边NOx的浓度与交通状况有关，车流量越大，车辆阻塞时间越长，NOx的浓度越高；不同类型车辆对路边NOx的贡献不同，大型车和中型车的贡献要比小型车、摩托车和助动车大得多；路边空气污染和影响因素与传统空气监测数据有较大差别。     

程序升温条件下铁及其氧化物在CO存在时对N_2O的还原机理

应用热综合分析仪 (TG FTIR)研究了在还原性气氛下Fe及其氧化物对N2 O的催化还原作用 .研究发现铁氧化物对氮氧化物的催化还原能力相当弱 ,而Fe可以高效地降低N2 O分解的初始温度和提高N2 O向N2 的转化率 .在Fe和CO的作用下 ,N2 O的初始分解温度为 92 0K和 10 0 0K .在 112 3K时 ,N2 O的转化率达到 95 %和 80 % .TG/DSC曲线表明了在Fe与N2 O反应过程中CO的作用表现为通过与N2 O在反应表面的竞争吸附使铁氧化物还原为金属铁 ,X射线衍射证明Fe与N2 O反应后的氧化物为Fe2 O3 ;扫描电镜对反应后Fe表面物理形态的研究发现 ,在CO作用下 ,Fe的表面呈松散结构 ,可以保证Fe对氮氧化物反应的连续进行     

Emission of nitrous oxide from rice-wheat systems of Indo-Gangetic plains of India

Nitrous oxide (N₂O) accounts for 5%of the total enhanced greenhouse effect and responsiblefor the destruction of the stratospheric ozone. The rice-wheat cropping system occupying 26 million ha ofproductive land in Asia could be a major source ofN₂O as most of the fertilizer N in this region isconsumed by this system. Emission of N₂O asinfluenced by application of urea, urea plus farm yardmanure (FYM), and urea plus dicyandiamide (DCD), anitrification inhibitor, was studied in rice-wheatsystems of Indo-Gangetic plains of India. Total emissionof N₂O-N from the rice-wheat systems varied between654 g ha^-1 in unfertilized plots and 1570 g ha^-1 in urea fertilized plots. Application of FYM and DCDreduced emission of N₂O-N in rice. The magnitude ofreduction was higher with DCD. In wheat also N₂O-Nemission was reduced by DCD. FYM applied in rice had noresidual effect on N₂O-N emission in wheat. In riceintermittent wetting and drying condition of soilresulted in higher N₂O-N emission than that ofsaturated soil condition. Treatments with 5 irrigationsgave higher emissions in wheat than those with 3irrigations. In rice-wheat system, typical of a farmer'sfield in Indo-Gangetic plains, where 240 kg N isgenerally applied through urea, N₂O-N emission is1570 g ha^-1 (0.38% of applied N) and application ofFYM and DCD reduced it to 1415 and 1096 g ha^-1,respectively.     

The Kyoto Protocol and non-CO2 Greenhouse Gases and Carbon Sinks

Many trace constituents other than carbon dioxide affect the radiative budget of the atmosphere. The existing international agreement to limit greenhouse gases, the Kyoto Protocol, includes carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆) and credit for some carbon sinks. We investigate technological options for reducing emissions of these gases and the economic implications of including other greenhouse gases and sinks in the climate change control policy. We conduct an integreated assessment of costs using the MIT Emissions Prediction and Policy Analysis (EPPA) model combined with estimates of abatement costs for non-CO₂ greenhouse gases and sinks. We find that failure to take advantage of the other gas and sink flexibility would nearly double aggregate Annex B costs. Including all the GHGs and sinks is actually cheaper than if only CO₂ had been included in the Protocol and their inclusion achieves greater overall abatement. There remains considerable uncertainty in these estimates, the magnitude of the savings depends heavily on reference projections of emissions, for example, but these uncertainties do not change the overall conclusion that non-CO₂ GHGs are an important part of a climate control policy.     

城市污水A~2/O处理系统好氧池N_2O和NO的释放特征及影响因素

以某污水处理厂好氧曝气池为研究对象,利用N_2O和NO在线检测仪,监测好氧池不同空间位置处N_2O和NO的释放量,考察了氮素浓度、溶解氧及p H值对N_2O和NO释放量的影响.该污水处理厂好氧池DO浓度在0.24~1.12mg/L之间,且大多处于0.6mg/L左右,较低的DO导致NO2--N浓度沿水流推流方向不断积累;相应的,N_2O和NO释放量沿水流推流方向不断升高,并于好氧池末段达到最高值.NO释放NO2--N量与浓度显著正相关,N_2O释放量与NO2--N浓度也有一定的相关性,但没有NO显著.基于空间检测数据估算获得该污水处理厂N_2O释放量占进水NH_4+-N比例为6.34%~8.83%,NO释放量占进水NH4+-N比例为0.033%~0.034%.     

Impact of dicyandiamide on emissions of nitrous oxide, nitric oxide and ammonia from agricultural field in the North China Plain

Nitrous oxide(N_2O), nitric oxide(NO) and ammonia(NH_3) emissions from an agricultural field in the North China Plain were compared for three treatments during a whole maize growing period from 26 June to 11 October, 2012. Compared with the control treatment(without fertilization, designated as CK), remarkable pulse emissions of N_2O, NO and NH_3 were observed from the normal fertilization treatment(designated as NP) just after fertilization, whereas only N_2O and NH_3 pulse emissions were evident from the nitrification inhibitor treatment(designated as ND). The reduction proportions of N_2O and NO emissions from the ND treatment compared to those from the NP treatment during the whole maize growing period were 31% and 100%, respectively. A measurable increase of NH_3 emission from the ND treatment was found with a cumulative NH_3 emission of 3.8 ± 1.2 kg N/ha,which was 1.4 times greater than that from the NP treatment(2.7 ± 0.7 kg N/ha).     

On-board measurements of gaseous pollutant emission characteristics under real driving conditions from light-duty diesel vehicles in Chinese cities

A total of 15 light-duty diesel vehicles(LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons(HC) and nitrogen oxides(NOx) at different speeds, chemical species profiles and ozone formation potential(OFP) of volatile organic compounds(VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOxhad been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOxemissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%–45.2%, followed by aromatics and alkenes. The most abundant species were propene,ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity(MIR)method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%–91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene.     

池火灾评价法在环氧乙烷罐区的应用研究

以某石油化工厂区为工程应用背景,通过对环氧乙烷储罐区计算模型的建立,应用池火灾评价法对环氧乙烷储罐发生池火灾的热辐射伤害区域进行了定量计算,得出环氧乙烷罐区发生池火灾的各级影响半径和造成的伤害程度。结果表明,只有当人员撤离罐区67.35 m范围外方可避免受到热辐射伤害。从环氧乙烷罐区的整体安全性出发,提出了具体的防护措施和建议,为企业的安全管理工作提供参考依据。     

石墨烯修饰的二氧化钛纳米管电极光电催化去除铜氰络合物研究

首先采用阳极氧化法制备了二氧化钛纳米管电极,进一步通过电化学循环伏安法制备了石墨烯(GO)修饰的二氧化钛纳米管电极.同时,采用SEM对电极的形貌进行了表征分析.光电化学测试分析结果表明,石墨烯修饰二氧化钛纳米管电极的电极光电响应性能得到了提高.最后,采用制备的电极为光阳极,通过光电催化氧化方法对铜氰络合物进行了去除研究.结果表明:在电压为2.0 V的条件下,采用二氧化钛纳米管电极,反应120 min后,剩余总氰的含量及铜的回收率分别为4.0%和96.3%;采用石墨烯修饰的二氧化钛纳米管,反应60 min后,剩余总氰的含量及Cu的回收率分别为0.3%和99%.可以看出,经石墨烯修饰的二氧化钛纳米管显示出了较好的光电催化去除铜氰络合物的效果.     

三合一脱硝技术在中小型燃水煤浆锅炉上的应用研究

中小型燃煤锅炉燃烧化石燃料过程中释放的氮氧化物,对环境造成的污染早就已经变成万众瞩目的焦点话题.而中小型锅炉又是当前大部分聚酯厂家的首选,解决这类型的锅炉的脱销难题,对于聚酯行业在当前环保指标压力下,研究中下锅炉脱销技术效果及组合应用,具有较强的现实意义.当前对于NOx的治理方法,有低氮燃烧、选择性非催化还原法(SNCR)和选择性催化还原法(SCR)等.本文就是在此背景下综述三合一脱硝技术在中小型燃水煤浆锅炉上的应用研究,及在工厂实际改造的工程运用案例.通过对氮氧化物的形成机理,工厂实际工况,选择脱销方法的考虑角度,以及实际采取的解决办法,并且对比脱销前后的指标数据的分析等方面,详细的阐述了三合一技术的充分可靠性,以及经济适用性.