Organic Emissions from a Wood Stove and a Pellet Stove Before and After Simulated Atmospheric Aging

Logwood and pellet stoves are popular heating sources around the world. The particulate matter emitted from such stoves contains organic particulate matter (OM), soot, and ash, each of which may have significant effects on climate and health. In this study, the primary OM (POM) emitted from a wood stove and a pellet stove operated according to standard Swiss testing protocols were characterized using aerosol mass spectrometry. The POM mass spectra were found to be highly reproducible, and contained CO⁺ as the dominant ion. Because the POM emitted by such stoves is typically enhanced by the condensation of gaseous organics following atmospheric aging, the secondary OM (SOM) formation potential of these stoves was simulated using the Micro Smog Chamber (MSC) designed by Keller and Burtscher in 2012 Keller, A., and Burtscher, H. (2012). A Continuous Photo-Oxidation Flow Reactor for a Defined Measurement of the SOA Formation Potential of Wood Burning Emissions. J. Aerosol Sci., 49:9–20, doi:10.1016/j.jaerosci.2012.02.007.[Crossref], [Web of Science ®] , [Google Scholar]. In general, OM emission factors from MSC-aged aerosols were comparable to lower-time-resolution results from the literature, although the MSC exposed aerosols to much higher concentrations of oxidants and therefore produced OM that was more oxidized than expected for atmospheric samples. In addition, the logwood-stove particles remained highly aspherical even after oxidation, indicating that mixing with an external aerosol is required for these particles to become spherical. The one exception to this observation occurred when the wood failed to ignite and appeared to generate tar-ball OM particles.     

CO助燃剂的新发展

本文陈述了CO助燃剂近年来的发展概况,并介绍了国内近年新开发的铂剂及稀土复合氧化物助燃剂在实际生产中的应用情况。     

低温CO催化氧化负载型Pd催化剂研究进展

综述了低温CO催化氧化负载型Pd催化剂在制备方法、载体的选用和催化机理等方面的研究进展,并介绍了该类催化剂的最新进展.在文章末对该催化剂领域尚待深入研究的问题进行了探讨.     

Aerosol Emissions from Outdoor Firework Displays

The results of investigations on the emission of particulate matter from three outdoor firework displays are presented. During these events, possibly harmful and toxic aerosol emissions were measured. Aerosols in the size range from 30 to 450 nm were detected. The maxima in the observed particle size distribution were between 80 and 175 nm, and the highest value determined was ～1.3 · 10⁶ particles per cm³, while the highest mass concentration was approximately 1.8 mg m^–3. The time‐averaged particle mass concentration did, however, not exceed 0.7 mg m^–3 (over 15 min).     

从一氧化碳生产草酸

介绍、对比了传统的草酸生产方法－甲酸钠法和技术先进的羰基合成法。     

松木屑水热提质过程及其燃烧特性

以松木屑为原料,采用高压反应釜,在高压、液固质量比12:1、搅拌转速150 r/min、反应时间1 h的条件下,在220?260℃温度范围内进行水热提质实验,对产物进行分析,研究温度对燃料特性、燃料性能及动力学特性的影响. 结果表明,松木屑的碳含量和热值随水热提质温度升高逐渐增大,260℃时含碳量由48.10%增加到69.05%,热值由19.12 MJ/kg增加到26.66 MJ/kg. 松木屑的热值增长趋势与其它生物质相同,但增长幅度异于其它生物质. 水热提质过程中,木屑各组分发生脱羧、脱水、聚合、芳香化等反应,大分子物质分解成小分子物质如气体和有机酸等. 水热提质有助于改善着火性能,随水热温度提高,最大燃烧速率对应的温度降低,燃烧时间延长. 原木屑的燃烧反应为二级反应,水热提质后燃烧反应为一级反应,且活化能显著降低,为33.68 kJ/mol. 水热提质可显著提高木屑的能量密度,改善其燃烧性能.     

一氧化碳生产草酸

简述CO生产草酸的甲酸钠法和CO氧化偶连法,着重介绍CO氧化偶联制草酸酯的发展历史和工艺研究的进展情况,并对草酸工业的发展提出建议.     

一氧化碳生产草酸

简述CO生产草酸的甲酸钠法和CO氧化偶连法,着重介绍CO氧化偶联制草酸酯的发展历史和工艺研究的进展情况,并对草酸工业的发展提出建议。     

一氧化碳制备二甲醚的研究进展

简述了二甲醚的性质、用途,详细阐述了用一氧化碳制备二甲醚的研究进展及各合成方法的工艺特点.指出了用一氧化碳制二甲醚具有广阔的发展前景和良好的经济效益.     

Characterization of Soot Aerosol Produced from Combustion of Propane in a Shock Tube

The knowledge of yields and properties of soot from combustion of hydrocarbon fuels is crucial for accurate evaluation of the impacts of primary aerosols on air quality and climate. This study presents measurements of soot generated from combustion of propane in a shock tube, using independently adjustable fuel equivalence ratio (φ), temperature, and pressure. The characterization of soot yields inside the shock tube by in situ laser extinction is complemented with a set of comprehensive measurements of soot transferred into a fluoropolymer chamber, including particle size distributions, elemental carbon (EC) mass fraction, effective density, mass fractal dimension (Dfm), dynamic shape factor (χ), and optical properties. The properties of soot particles and the soot yield are sensitive to combustion conditions and the duration of the combustion experiment. High-temperature combustion with φ = 2.5 produces small fractal (Dfm = 2) soot particles composed mainly of EC (up to 90%), at a low mass yield. Particles from lower temperature combustion contain a significant fraction of organic material (～50%). Using rich fuel mixtures (φ = 4.0 and 8.0) significantly increases particle size and soot mass yield. At lower temperatures, compact (Dfm = 3) and nearly spherical (χ = 1.1) aggregates with high organic content are formed, whereas at higher temperatures, the particles are fractal and closely resemble those obtained using φ = 2.5. Single scattering albedo (SSA) varies from 0.15 for fractal particles to 0.75 for compact particles. For soot generated at high equivalence ratios, SSA can be used as a proxy for particle morphology and EC content.

Copyright 2012 American Association for Aerosol Research     

两步法制备竹质活性炭

结合磷酸活化法与氯化锌活化法化制备活性炭,在较低的活化温度下取得了良好的活性炭.活化总时间为60min,磷酸活化温度500 ℃与氯化锌活化温度400 ℃,浸渍率为150%的优化条件下制得的活性炭,其亚甲基蓝脱色力为19 mL,碘吸附值为861 mg/g,孔径集中在4.5 nm,并且比表面积高达1696 m2/g,大孔仅占0.381%.     

Determination of Volatility Distributions of Primary Organic Aerosol Emissions from Internal Combustion Engines Using Thermal Desorption Gas Chromatography Mass Spectrometry

A new technique for measuring the primary organic aerosol (POA) emissions from internal combustion engines is presented. The method combines thermal-optical OC/EC analysis and thermal desorption gas chromatography mass spectrometry (TD-GC-MS) of quartz filter samples collected using a dilution sampler to quantify the total emissions of low-volatility organics and to distribute them across the volatility basis set. These data can be used in conjunction with partitioning theory to predict the gas-particle partitioning and thus the total amount of POA over the entire range of atmospheric conditions. The approach is evaluated using POA emissions data from two gas-turbine engines and one diesel generator. To evaluate the new method, we directly measured the effects of temperature and concentration on gas-particle partitioning of the emissions from each. Predictions based on the volatility distributions derived from the filter analyses are consistent with the direct partitioning measurements. The new approach represents a major improvement over the traditional assumption of nonvolatile POA emissions, which over predicts actual POA emissions from these sources by a factor of 2–4 at typical ambient concentration and temperature. By using quartz filter samples, this new technique is designed to be applied to routine source test data. Volatility distributions derived using this new approach can also be applied directly to the large catalog of quartz filter data used by existing emission inventories and models. The emissions data derived from this approach are designed for use in the next generation of chemical transport models and emissions inventories that employ the volatility basis set approach to explicitly track the gas-particle partitioning of POA emissions.

Copyright 2012 American Association for Aerosol Research     

CO吸附剂制备及其吸附脱除微量CO的性能

介绍了CO吸附剂的制备方法,研究了该吸附剂在固定床温度30 ℃、CO分压为6 kPa(a)下吸附一氧化碳的动态吸附性能,测定了穿透曲线,动态吸附容量为2.138 5 mmol/g,并用BET吸附仪测定了制备的CO吸附剂比表面积,用电感耦合等离子体原子发射光谱(ICP)测定其离子交换度为52%,含铜量为9.52%(质量分数)。通过粉末X射线衍射仪(XRD)和场发射扫描电子显微镜(SEM)表征发现,水热交换法制备CO吸附剂,Cu²⁺有效地取代了NaY原粉中Na⁺,经过焙烧还原后仍然能够维持原骨架结构的完整。用NH₃-TPD考察了改性前后吸附剂酸度的变化以及用H₂-TPR考察了吸附剂合适的还原温度。采用130 ℃氮气吹扫的方法再生,再生彻底并且吸附效果稳定。     

Carbon Nanotube and Fullerene Emissions from Spark-Ignited Engines

Particles were collected from the exhaust of Indian autorickshaws with natural gas and gasoline-fueled spark-ignited engines. Transmission electron microscopy was used to determine the size and shape of 2121 systematically selected particles. Particles were largely soot agglomerates and other types documented in the literature, but approximately 10% of the nonvolatile particles were multiwalled carbon nanotubes and fullerenes, forms of crystalline carbon distinct from soot. Autorickshaw fullerenic particle number emissions can be above 10¹¹ per kg of fuel consumed. The nanotubes identified from the exhaust of autorickshaws average 168 nm in length. This is shorter than those nanotubes of greatest health concern, but given the paucity of toxicological data on carbon nanotubes and fullerenes, the potential environmental abundance from engine sources warrants closer attention. In particular, a broader range of engine types should be considered.

[Supplemental materials are available for this article. Please go to the publisher's online edition of Aerosol Science & Technology to view the online files.]

Copyright 2012 American Association for Aerosol Research     

The Catalytic Synthesis of Hydrocarbons from Carbon Monoxide and Hydrogen

The increasing demand for energy, coupled with the uncertainty and expense of crude oil imports, has renewed interest in the production of fuels and chemicals from hydrogen-deficient materials. These energy sources such as coal, residua, oil shale, and tar sands can be gasified with steam and oxygen to produce a gas containing large quantities of carbon monoxide and hydrogen. Once methane is removed from this CO/H₂ mixture it is purified to remove S poisons and then reacted over a catalyst to produce a variety of organic products. The synthesis of hydrocarbon products, with the exception of methane, is commonly referred to as the Fischer-Tropsch synthesis reaction.     

Influence of Impurities and Role of Iron Carbides in Deposition of Carbon from Carbon Monoxide

The dissociation of carbon monoxide in contact with iron oxide has been studied; the temperature range of the reaction has been determined; the composition and structure of the catalyst has been established; and factors inhibiting or accelerating the rate of reaction are discussed. Some related observations on used blast-furnace fire-clay linings are included.     

Molecular Simulations in Activated Carbons for Carbon Monoxide Removal From Wet Mixture of Hydrogen and Carbon Monoxide

Activated carbons are porous materials with a high surface area which are widely used in gases separation and catalysis. This work focuses on the understanding of the separation characteristics of activated carbons for purifying hydrogen from the wet mixture of hydrogen and carbon monoxide (in hundreds of ppm). This study would build a basic insight of the separation mechanism of the activated carbon and determine whether activated carbons are suitable for CO removal from the mixture. Systematic Grand Canonical Monte Carlo (GCMC) simulations have been carried out to assess the adsorption properties and selectivity of the activated carbon to the gaseous mixture with different gas phase compositions, temperatures, and pressures. The calculated adsorption isotherms, both for single and multi-component gas mixture, and isosteric heats of adsorption on the activated carbon showed reasonably good agreement with the experimental data available in the literature.     

Liquid Fuels from Alternative Carbon Sources Minimizing Carbon Dioxide Emissions

The energy needs of the world continue to grow, as does the resulting environmental impact. Policy makers continue to call for alternative energies to replace today's petroleum‐based liquid fuels. However, liquid fuels have significant advantages, and it is probably unwise to abandon the existing infrastructure without appropriately exploring alternatives to lessen the environmental burden of producing liquid fuels. Biomass and coal are often proposed as alternatives to petroleum‐based carbon sources, but those processes lose a significant amount of their potential product to unwanted carbon dioxide emissions. However, combining biomass and coal with cleaner natural gas yields processes with less environmental impact to produce liquid fuels with small, zero, or even negative carbon dioxide emissions. Our process synthesis approach is applied to commonly encountered liquid fuel production methods to identify promising routes and to establish feasibility limits on those less promising alternatives. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2062–2078, 2013     

利用褐煤热解制备一氧化碳的热力学以及动力学研究

褐煤是一种高水分、易挥发、低密度和中低热量的低劣煤。为了提高褐煤利用效率,采用褐煤热解制备一氧化碳。通过Ellingham图筛选出有助于褐煤热解分解制备一氧化碳的氧化物,并且利用热力学对该过程进行分析,同时对该过程的反应动力学及反应机理进行探索。通过热力学分析发现,CeO_2褐煤可以制备一氧化碳,其转化率最高可以达到99.00%。该过程主要分为两个部分:925℃以下褐煤的自身气化和高温阶段的CeO_2与C的反应,且高温对该反应有促进作用。通过Kissinger和Flynn-Wall-Ozawa(FWO)方法对CeO_2褐煤分解过程的活化能研究以及通过Coats-Redfem方法对反应机理的探索,最终确定CeO_2褐煤制备一氧化碳的反应动力学模型。该研究为褐煤热解提出一条途径。     

磷酸活化法活性炭的吸附性能和孔结构特性

采用磷酸活化法在不同操作条件下制备得到各种活性炭,实验测定了相应活性炭的亚甲蓝吸附值、氮气吸附等温线及活性炭的比表面积和孔容。分别研究了磷酸活化法制备活性炭的主要操作参数,如浸渍比、活化时间和活化温度对活性炭吸附性能和活性炭的孔结构特征的影响。实验结果表明,浸渍比是磷酸活化法制备活性炭的最重要的影响因素。综合考虑活性炭的吸附性能和孔结构特征受活化操作参数的影响规律,探讨了磷酸活化法生产木质活性炭的最优操作参数。在实验范围内,磷酸活化法制备木质活性炭的最优操作条件宜选择浸渍比为100％～150％、500℃左右活化温度和60～90min的活化时间。