国四柴油公交车实际道路气态污染物与超细颗粒物排放特征研究

采用车载排放测试系统于上海市城区开展了一辆国四重型柴油公交车的实际道路排放测量。测试系统集成了一台Horiba公司的OBS 2200气态污染物车载排放测试和TSI公司的EEPS 3090超细颗粒物粒径谱仪。测试结果给出了被测公交车在不同道路类型上的气态污染物和颗粒物及其粒径分布的平均排放因子。测试车辆为装有SCR排放处理系统的国四公交车,实际道路NOx排放因子为8.2 g·km-1,颗粒数量和质量排放因子分别为6.4×1014个·km-1和0.36 g·km-1。颗粒物粒径总体呈单模态分布。颗粒数峰值位于70~80 nm之间。研究获得的瞬态颗粒物粒径谱排放结果为说明实际行驶工况下的颗粒物排放机理提供了可能。     

燃煤有机污染物生成排放特性与采样方法研究进展

煤燃烧过程在生成SO_2、NO_x和颗粒物等常规污染物的同时,还会产生有机污染物。我国燃煤电厂数量多,燃煤产生的非甲烷挥发性有机物(NMVOC)已经占到了人为源排放总量的1/3。然而,已有的针对有机污染物的研究主要关注的是工业源和室内环境中的挥发性有机物,对燃煤过程产生的有机污染物研究较少。由于煤的组分复杂,燃烧温度高、燃烧工况多变,且产生高尘高湿的烟气,这些特殊环境决定了煤燃烧过程有机污染物的生成排放特性及其采样方法与工业源有所不同。本文对原煤有机污染物的前体赋存形态、燃煤过程有机污染物的生成排放特性以及有机污染物的采样与分析方法进行了较全面的综述,并探讨了燃煤有机污染物相关研究的发展方向。     

PM_(2.5)在线源解析质谱监测系统在某国控站点的应用研究

首先介绍了PM_(2.5)在线源解析质谱监测系统及其管理功能和意义,其次利用系统在某国控站点进行了具体应用,结果显示,监测期间点位受机动车尾气、燃煤源和二次无机源的影响较大,点位污染天气的发生主要受到机动车尾气排放累积的影响,且PM_(2.5)污染过程主要成因为高湿的气象条件加速了气态污染物(SO_2、NO_2)向颗粒态污染物的二次转化,同时机动车尾气颗粒物不断吸湿增长,造成PM_(2.5)的显著上升。     

柴油车尾气污染物排放特征及尾气处理研究

柴油汽车性能优越,在交通领域应用广泛,但是随之而来的尾气排放问题已经成为空气污染的重要源头。柴油车尾气中的颗粒物、NO_X以及VOCs等成分给周围生态环境治理带来了极大的挑战。通过开展污染物特征分析,明确了柴油车尾气中的主要污染物成分和含量,并针对性地探讨了尾气处理措施,以期缓解环境污染问题,为同类研究提供参考。     

城市重点区域机动车排气污染特征分析及对策研究

对中心城区空气质量监测站周边道路的车辆行驶状况进行调查,根据主干道的出行特征、车辆类型及车流量等进行综合分析,结合基础排放因子和修正系数,使用源强法计算重点区域内的污染物排放量,分析不同时段、不同车型的污染物排放占比,为中心城区机动车排气污染治理提供科学有效的决策依据.     

石化企业挥发性有机物排放特征及污染潜势研究

在调查石化企业生产工艺的基础上,采用吸附管吸附-热脱附/气相色谱-质谱法,对石化企业硫磺回收工艺废气、PX工艺加热炉废气、厂区污水处理废气及厂界环境空气进行了采样分析。对各排放源的挥发性有机物(VOCs)的排放水平及源成分进行了研究,并对排放源的污染潜势进行了评估分析。结果表明,石化企业以上排放源VOCs的排放质量浓度在32~95 mg/m~3,环境质量浓度在1.5 mg/m~3左右;共定量检测出21种挥发性有机物,各排放源的排放特征与工艺密切相关。此外,芳香烃类化合物为石化企业首要光化学污染物类别,主要光化学污染物包括:甲苯、苯。     

绿色轮胎:原材料必须也要“绿”

进入2013年,笼罩了大半个中国、持续一个多月的雾霾天气,至今使人们记忆犹新。媒体将制造雾霾污染的矛头直指汽车行业。汽车尾气排放是大气污染物的主要来源之一,也是影响雾霾天气的主要因素。以北京市为例,北京市环保局的统计结果表明,北京机动车排放的NOx约占全市NOx排放总量的58%,排放的挥发性有机物约占全市挥发性有机物排放总量的40%,NOx、挥发性有机物等通过化学反应都可形成细颗粒物(PM2.5)和臭氧污染。根据专家初步测算,北京市机动车排放形成的PM2.5约占总量的22.2%。     

安庆石化车用尿素担当“环保先锋”

PM2.5,指每立方米空气含可入肺颗粒含量,是监测空气质量的重要指标,近期以来更成为各大城市环境质量的关键指数。机动车尾气排放,是PM2.5居高不下的主要原因。机动车尾气控制的催化还原剂——车用尿素溶液正担当＂环保先锋＂,成为降低PM2.5的新法宝。2012年来,中国石化安庆分公司化肥部新增车用尿素生产装置,目前首批10t车用尿素顺利完成生产任务。车用尿素,用作于柴油车尾气处理液原料,应用于柴油发动机,可有效降低柴油车尾气中氮氧化物和颗粒物（PM）,达到提高空气质量、改善环境的目的。     

燃煤有机污染物排放及其控制技术研究展望

有机污染物排放是导致大气复合型污染、诱发雾霾、产生光化学烟雾的重要诱因,是当前研究的热点问题。燃煤是有机污染物的来源之一。本文综述了燃煤有机污染物的排放特性,包括燃煤有机物的排放浓度及主要组分,影响燃煤有机物生成的因素,指出燃煤有机污染物浓度较低,苯系物是其重要组成之一。分析了烟气系统中有机物的迁移转化以及烟气处理设施（选择性催化还原脱硝、湿法脱硫、电除尘、湿式电除尘、低低温电除尘）的协同去除作用。最后基于吸附技术和催化技术的研究现状,展望了未来燃煤有机污染物控制的研究方向为：结合现有设备的协同去除作用,优化工艺条件,开发适合燃煤有机物的高效吸附剂和催化剂,开发集高效吸附/氧化/烟气协同净化技术于一体的燃煤有机物高效控制技术。     

新一批大气污染源清单编制指南发布

<正>环境保护部日前发布第二批大气污染物源排放清单编制技术指南,涉及大气可吸入颗粒物(PM10)、道路机动车、非道路移动源、生物质燃烧源、扬尘颗粒物等,以强化科技支撑大气污染防治,指导各地开展大气排放清单编制。据环保部相关负责人介绍,排放清单是识别污染来源、支撑模式模拟、分析解释观测结果和制定减排控制方案的重要基础,对于探究大气化学与气候相互作用、识别大气复合污染来源等科学问题,以及污染物总量减排、空气质量达标等环境管理问     

Evaluation of the potential air pollution from fuel combustion in industrial boilers in Kocaeli,Turkey

The potential air pollution from the fuel combustion in the uncontrolled industrial boilers in Kocaeli, the most industrialized area in Turkey, was evaluated by using the emission factors determined based on the flue gas measurements conducted at over 100 industrial plants in the area. The emissions were modeled for conventional combustion pollutants by a Gaussian dispersion model to determine the possible contribution of these emissions to the background air pollution. Results show that the emission factors calculated for the pollutants including CO, SO₂, NO₂, PM and formaldehyde are comparable with those given in literature for other countries. On the other hand, the emission factors are laid in a wide range due to the presence of many factors affecting the emission of the pollutants, including the characteristics of fuel, boiler and combustion practice. The Gaussian air dispersion model applied by using the emission factors indicated that the effect of the industrial fuel combustion on the background air pollution was low for the conventional combustion pollutants despite the high number of industrial boilers in the area, suggesting the significant contribution of other sources, i.e. residential heating and mobile sources.     

Various strategies for reducing Nox emissions of biodiesel fuel used in conventional diesel engines: A review

Energy demand, decreasing fossil fuel reserves, and health-related issues about pollutants have led researchers to search for renewable alternative fuels to either partially or fully replace fossil fuels. Among many alternative fuels, biodiesel became one of the most popular choices due to similar properties to that of conventional diesel. Biodiesel produces slightly lower brake thermal efficiency compared to that of conventional biodiesel, but has an advantage of reduced emissions of CO₂, CO, HC, and smoke. However, biodiesel shows higher NOx emission which, when used in increased biodiesel market, may become a serious problem. Various strategies were attempted by different researcher to reduce NOx emissions. In this paper, various strategies, adapted for reducing NOx emissions of biodiesel fuel used in diesel engines for automobile applications, are reviewed and discussed. The strategies are grouped into three major groups, namely combustion treatments, exhaust after-treatments, and fuel treatments. Among various strategies discussed, fuel treatments, such as low temperature combustion, mixing fuel additives and reformulating fuel composition, reduce NOx emission without compromising other emission and performance characteristics and they seem to be promising for future biodiesel fuel.     

Biodiesel blend effects on common-rail diesel combustion and emissions

Biodiesel (fatty acid methylesters) blends with fossil diesel at a mixing ratio between 0.5 and 5 vol.% are widely offered as automotive fuels in Europe. The target for the future is to bring this ratio to at least 10%, in order to increase the share of renewable energy in transport. There is however limited evidence on the effects of such blends on the combustion and emissions of diesel engines not originally designed to operate on biodiesel blends. In this study, a number of experiments with 10 vol.% (B10) biodiesel fuel of palmoil origin were performed on a light-duty common-rail Euro 3 engine. The measurements included in-cylinder pressure, pollutants emissions, and fuel consumption. Combustion effects were limited but changes in the start of ignition and heat-release rate could be identified. Emission effects included both higher and lower smoke and NOx, depending on the operation point. The results on the engine bench were compared against a Euro 3 common-rail light-duty vehicle driven on the chassis dynamometer, in order to include the effects of emission control systems (EGR and oxidation catalyst). In addition to the palm biodiesel, an RME-diesel blend was also tested to examine the effects of a fuel with different characteristics. Both biodiesel blends reduced PM emissions and only marginal effects on NOx over the certification test could be identified. The results of this study show that up to 10% biodiesels could be used on current diesel vehicles, without significantly affecting vehicle emission performance.     

PAH and other emissions from burning of JP-8 and diesel fuels in diffusion flames

Jet fuel JP-8 is of technical interest to the military aviation industry. JP-8 is now the single battlefield fuel for all US Army and Air Force equipment, replacing gasoline altogether and gradually replacing diesel fuel. Hence, emissions from the combustion of this fuel are the subject for this investigation. The emissions from the combustion of JP-8 fuel are examined and are compared to those from diesel fuel No. 2, burned under identical conditions. Combustion occurred inside a laboratory furnace in sooty diffusion flames, under adverse conditions that typically emit large amounts of products of incomplete combustion (PIC). Under such conditions, even compounds that otherwise might appear only in trace amounts were present in sufficient quantities for detection. The study reports on emissions of CO, light volatile organic compounds, semi-volatile organic compounds with an emphasis on polycyclic aromatic hydrocarbons (PAH), particulate emissions, oxides of nitrogen (NO_x) and oxides of sulfur (SO₂). Some PAH compounds are suspected of posing a threat to human health, benzo[a]pyrene being listed as a bio-accumulative toxin by the EPA. An afterburner was also used to examine the effects of longer furnace residence time. Results have demonstrated that PAH emissions from the combustion of diesel fuel were higher than those of JP-8, under most conditions examined. Moreover, as the temperature of the primary furnace was increased, in the range of 600–1000 °C, most of the emissions from both fuels increased. Particulate emissions were reduced by the afterburner, which was operated at 1000 °C, only when the primary furnace was operated at the lowest temperature (600 °C), but that condition increased the CO emissions. Overall, transient combustion of these two fuels, burning in laminar and sooty diffusion flames, did not reveal major differences in the emissions of the following PIC: C1–C4 light aliphatic hydrocarbons, PAH, CO and particulate matter.     

Sensitivity of Diesel Particulate Material Emissions and Composition to Blends of Petroleum Diesel and Biodiesel Fuel

A number of investigations have examined the impact of the use of biodiesel on the emissions of carbon dioxide and regulated emissions, but limited information exists on the chemical composition of particulate matter from diesel engines burning biodiesel blends. This study examines the composition of diesel particulate matter (DPM) emissions from a commercial agriculture tractor burning a range of biodiesel blends operating under a load that is controlled by a power take off (PTO) dynamometer. Ultra-low sulfur diesel (ULSD) fuel was blended with soybean and beef tallow based biodiesel to examine fuels containing 0% (B0), 25% (B25), 50% (B50), 75% (B75), and 100% (B100) biodiesel. Samples were then collected using a dilution source sampler to simulate atmospheric dilution. Diluted and aged exhaust was analyzed for particle mass and size distribution, PM_2.5 particle mass, PM_2.5 organic and elemental carbon, and speciated organic compounds. PM_2.5 mass emissions rates for the B25, B50, and B75 soybean oil biodiesel mixtures had 20%–30% lower emissions than the petroleum diesel, but B100 emissions were about 40% higher than the petroleum diesel. The trends in mass emission rates with the increasing biodiesel content can be explained by a significant decrease in elemental carbon (EC) emissions across all blending ranges and increasing organic carbon (OC) emissions with pure biodiesel. Beef tallow biodiesel blends showed similar trends. Nevertheless, it is important to note that the study measurements are based on low dilution rates and the OC emissions changes may be affected by ambient temperature and different dilution conditions spanning micro-environments and atmospheric conditions. The results show that the use of biodiesel fuel for economic or climate change mitigation purposes can lead to reductions in PM emissions and a co-benefit of EC emission reductions. Detailed speciation of the OC emissions were also examined and are presented to understand the sensitivity of OC emissions with respect to biodiesel fuel blends.

Copyright 2012 American Association for Aerosol Research     

Organic PM Emissions from Vehicles: Composition,O/C Ratio,and Dependence on PM Concentration

A suite of real-time instruments was used to sample vehicle emissions at the California Air Resources Board Haagen-Smit facility. Eight on-road, spark-ignition gasoline and three alternative vehicles were tested on a chassis dynamometer and the emissions were diluted to atmospherically relevant concentrations (0.5–30 μg/m³). An Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-ToF-MS) characterized the real-time behavior of the nonrefractory organic and inorganic particulate matter (PM) in vehicle emissions. It was found that the emission of particulate organic matter (POM) was strongly affected by engine temperature and engine load and that the emission concentrations could vary significantly by vehicle. Despite the small sample size, consistent trends in chemical characteristics were observed. The composition of vehicle POM was found to be related to overall PM mass concentration where the oxygen-to-carbon (O/C) ratio tended to increase at lower concentration and had an average value of 0.057 ± 0.047, with a range from 0.022 to 0.15. The corresponding fraction of particle-phase CO₂⁺, or f₄₄, ranged from 1.1% to 8.6% (average = 2.1%) and exhibited a linear variation with O/C. The average mass spectrum from all vehicles tested was also compared to those of hydrocarbon-like organic aerosol (HOA) observed in ambient air and the agreement is very high. The results of these tests offer the vehicle emissions community a first glimpse at the real-time chemical composition and variation of vehicle PM emissions for a variety of conditions and vehicle types at atmospherically relevant conditions and without chemical interferences from other primary or secondary aerosol sources.

Copyright 2015 American Association for Aerosol Research     

氨混合燃料体系的性能研究现状

氨不仅是一种成本低廉的化工原料,而且由于具有较高的能量密度、易于储运、燃烧不产生CO₂等优点被认为是一种有广泛应用前景的清洁燃料。氨燃料具有替代汽油、柴油等化石燃料的应用潜力,为解决环境污染和化石能源短缺等问题提供了新的途径。本文概述了氨燃料的理化特性、燃烧特性以及与多种材料的相容性,介绍了氨作为调合燃料的性能及应用研究进展,尤其对氨-汽油燃料、氨-柴油燃料、氨-正庚烷燃料等燃料体系的研究成果进行了总结。文章集中分析了氨作为发动机燃料的机遇和挑战,尤其指出了氨燃料的生产高能耗、毒性及腐蚀性、氨的燃烧缺陷等问题,并探讨了对应的解决方案。在碳达峰、碳中和的大背景下,氨燃料在我国的发展具有后发优势。     

Experimental investigation and mathematical modelling of wood combustion in a moving grate boiler

The use of biomass to generate energy offers significant environmental advantages for the reduction in emissions of greenhouse gases. The main objective of this study was to investigate the performance of a small scale biomass heating plant: i.e. combustion characteristics and emissions. An extensive series of experimental tests was carried out at a small scale residential biomass heating plant i.e. wood chip fired boiler. The concentrations of CO, NO_x, particulate matter in the flue gas were measured. In addition, mathematical modelling work using FLIC and FLUENT codes was carried out in order to simulate the overall performance of the wood fired heating system. Results showed that pollutant emissions from the boiler were within the relative emission limits. Mass concentration of CO emission was 550-1600 mg/m³ (10% O₂). NO_x concentration in the flue gas from the wood chips combustion varied slightly between 28 and 60 ppmv. Mass concentration of PM₁₀ in the flue gas was 205 mg/m³ (10% O₂) The modelling results showed that most of the fuel was burnt inside the furnace and little CO was released from the system due to the high flue gas temperature in the furnace. The injection of the secondary air provided adequate mixing and favourable combustion conditions in the over-bed chamber in the wood chips fired boiler. This study has shown that the use of wood heating system result in much lower CO₂ emissions than from a fossil fuel e.g. coal fired heating system.     

Sources and Health Risk of Organic Compounds in Respirable Particles in Tehran,Iran

Forty-one respirable particle (PM₄) samples were collected from October 2011 through March 2012. This timespan covered the fall and winter seasons in Tehran, Iran. The associated polycyclic aromatic hydrocarbon (PAH) and n-alkane concentrations were analyzed to investigate the sources of these compounds and health risks of the former. The average total PAH and n-alkane concentrations were 16.2 ng/m³ and 758 ng/m³, respectively. The most abundant PAHs were 2- and 3-ring compounds, while the most abundant n-alkanes were nC₁₆ and nC₁₈. The results of source identification by factor analysis (FA) are consistent with and complementary to those from diagnostic ratios (DRs). The PAH DRs indicate a dominant contribution from pyrogenic sources, in particular diesel engines from local traffic sources, while FA reveals a diesel-fuelled vehicle emission related factor, a gasoline engine emission-related factor, an industrial source factor and a wood combustion, incineration and tire tread source factor. The n-alkane DRs indicate dominant contributions from anthropogenic sources or vehicular emissions, while FA reveals a fossil fuel combustion factor and a biogenic source factor. Although the average BaP concentration was below the Iran Department of Environment's annual average standard of 1 ng/m³, the BaP-equivalent concentration of the PAHs (BaP_PEQ) indicates harmful effects cannot be ruled out. The ICR_L and ICR_U data suggests a potential cancer risk incidence of about 1–54 individuals per million in the population from a lifetime of 70 years inhalation of particle associated PAHs in Tehran. These findings highlight the importance of reducing emissions from traffic, in particular emissions from diesel-fuelled vehicles, in Tehran.     

Vegetable oils and animal fats as alternative fuels for diesel engines with dual fuel operation

Vegetable oils and animal fats are applicable as fuels in standard diesel engines after having adapted the fuel system for electronically controlled dual fuel regime oil/fat-fossil diesel. In this contribution, performance and emission characteristics of the engines running on rapeseed oil, lard, or chicken fat are given and compared to those of fossil diesel and fatty acid methyl esters. The results of engine tests of these fuels show a decrease in maximum power and maximum torque in comparison to fossil diesel due to a lower energy content of triacylglycerols. These values are influenced also by a type of the engine used at testing. When compared to fossil diesel, the opacity of oil/fat based fuels is higher for an engine with lower injection pressures while it is lower for an engine with higher injection pressures. The level of both controlled and uncontrolled emissions is low for all tested biofuels and is low also for the reference fossil diesel. The results of performance and emission tests for rapeseed oil containing 3 and 6 vol.% of anhydrous ethanol are comparable to those obtained for pure oil. In this paper, practical experiences based on long-term operation of adapted vehicle fleet fuelled with oil/fat-fossil diesel are mentioned.